diff options
Diffstat (limited to 'fs/notify')
| -rw-r--r-- | fs/notify/Kconfig | 1 | ||||
| -rw-r--r-- | fs/notify/Makefile | 4 | ||||
| -rw-r--r-- | fs/notify/dnotify/dnotify.c | 254 | ||||
| -rw-r--r-- | fs/notify/fanotify/Kconfig | 26 | ||||
| -rw-r--r-- | fs/notify/fanotify/Makefile | 1 | ||||
| -rw-r--r-- | fs/notify/fanotify/fanotify.c | 262 | ||||
| -rw-r--r-- | fs/notify/fanotify/fanotify.h | 50 | ||||
| -rw-r--r-- | fs/notify/fanotify/fanotify_user.c | 919 | ||||
| -rw-r--r-- | fs/notify/fdinfo.c | 179 | ||||
| -rw-r--r-- | fs/notify/fdinfo.h | 27 | ||||
| -rw-r--r-- | fs/notify/fsnotify.c | 255 | ||||
| -rw-r--r-- | fs/notify/fsnotify.h | 27 | ||||
| -rw-r--r-- | fs/notify/group.c | 210 | ||||
| -rw-r--r-- | fs/notify/inode_mark.c | 389 | ||||
| -rw-r--r-- | fs/notify/inotify/Kconfig | 16 | ||||
| -rw-r--r-- | fs/notify/inotify/Makefile | 1 | ||||
| -rw-r--r-- | fs/notify/inotify/inotify.c | 933 | ||||
| -rw-r--r-- | fs/notify/inotify/inotify.h | 28 | ||||
| -rw-r--r-- | fs/notify/inotify/inotify_fsnotify.c | 170 | ||||
| -rw-r--r-- | fs/notify/inotify/inotify_user.c | 571 | ||||
| -rw-r--r-- | fs/notify/mark.c | 375 | ||||
| -rw-r--r-- | fs/notify/notification.c | 323 | ||||
| -rw-r--r-- | fs/notify/vfsmount_mark.c | 200 |
23 files changed, 2990 insertions, 2231 deletions
diff --git a/fs/notify/Kconfig b/fs/notify/Kconfig index dffbb0911d0..22c629eedd8 100644 --- a/fs/notify/Kconfig +++ b/fs/notify/Kconfig @@ -3,3 +3,4 @@ config FSNOTIFY source "fs/notify/dnotify/Kconfig" source "fs/notify/inotify/Kconfig" +source "fs/notify/fanotify/Kconfig" diff --git a/fs/notify/Makefile b/fs/notify/Makefile index 0922cc826c4..96d3420d024 100644 --- a/fs/notify/Makefile +++ b/fs/notify/Makefile @@ -1,4 +1,6 @@ -obj-$(CONFIG_FSNOTIFY) += fsnotify.o notification.o group.o inode_mark.o +obj-$(CONFIG_FSNOTIFY) += fsnotify.o notification.o group.o inode_mark.o \ + mark.o vfsmount_mark.o fdinfo.o obj-y += dnotify/ obj-y += inotify/ +obj-y += fanotify/ diff --git a/fs/notify/dnotify/dnotify.c b/fs/notify/dnotify/dnotify.c index 7e54e52964d..abc8cbcfe90 100644 --- a/fs/notify/dnotify/dnotify.c +++ b/fs/notify/dnotify/dnotify.c @@ -29,17 +29,16 @@ int dir_notify_enable __read_mostly = 1; static struct kmem_cache *dnotify_struct_cache __read_mostly; -static struct kmem_cache *dnotify_mark_entry_cache __read_mostly; +static struct kmem_cache *dnotify_mark_cache __read_mostly; static struct fsnotify_group *dnotify_group __read_mostly; -static DEFINE_MUTEX(dnotify_mark_mutex); /* - * dnotify will attach one of these to each inode (i_fsnotify_mark_entries) which + * dnotify will attach one of these to each inode (i_fsnotify_marks) which * is being watched by dnotify. If multiple userspace applications are watching * the same directory with dnotify their information is chained in dn */ -struct dnotify_mark_entry { - struct fsnotify_mark_entry fsn_entry; +struct dnotify_mark { + struct fsnotify_mark fsn_mark; struct dnotify_struct *dn; }; @@ -51,27 +50,27 @@ struct dnotify_mark_entry { * it calls the fsnotify function so it can update the set of all events relevant * to this inode. */ -static void dnotify_recalc_inode_mask(struct fsnotify_mark_entry *entry) +static void dnotify_recalc_inode_mask(struct fsnotify_mark *fsn_mark) { __u32 new_mask, old_mask; struct dnotify_struct *dn; - struct dnotify_mark_entry *dnentry = container_of(entry, - struct dnotify_mark_entry, - fsn_entry); + struct dnotify_mark *dn_mark = container_of(fsn_mark, + struct dnotify_mark, + fsn_mark); - assert_spin_locked(&entry->lock); + assert_spin_locked(&fsn_mark->lock); - old_mask = entry->mask; + old_mask = fsn_mark->mask; new_mask = 0; - for (dn = dnentry->dn; dn != NULL; dn = dn->dn_next) + for (dn = dn_mark->dn; dn != NULL; dn = dn->dn_next) new_mask |= (dn->dn_mask & ~FS_DN_MULTISHOT); - entry->mask = new_mask; + fsnotify_set_mark_mask_locked(fsn_mark, new_mask); if (old_mask == new_mask) return; - if (entry->inode) - fsnotify_recalc_inode_mask(entry->inode); + if (fsn_mark->i.inode) + fsnotify_recalc_inode_mask(fsn_mark->i.inode); } /* @@ -83,29 +82,28 @@ static void dnotify_recalc_inode_mask(struct fsnotify_mark_entry *entry) * events. */ static int dnotify_handle_event(struct fsnotify_group *group, - struct fsnotify_event *event) + struct inode *inode, + struct fsnotify_mark *inode_mark, + struct fsnotify_mark *vfsmount_mark, + u32 mask, void *data, int data_type, + const unsigned char *file_name, u32 cookie) { - struct fsnotify_mark_entry *entry = NULL; - struct dnotify_mark_entry *dnentry; - struct inode *to_tell; + struct dnotify_mark *dn_mark; struct dnotify_struct *dn; struct dnotify_struct **prev; struct fown_struct *fown; - __u32 test_mask = event->mask & ~FS_EVENT_ON_CHILD; + __u32 test_mask = mask & ~FS_EVENT_ON_CHILD; - to_tell = event->to_tell; + /* not a dir, dnotify doesn't care */ + if (!S_ISDIR(inode->i_mode)) + return 0; - spin_lock(&to_tell->i_lock); - entry = fsnotify_find_mark_entry(group, to_tell); - spin_unlock(&to_tell->i_lock); + BUG_ON(vfsmount_mark); - /* unlikely since we alreay passed dnotify_should_send_event() */ - if (unlikely(!entry)) - return 0; - dnentry = container_of(entry, struct dnotify_mark_entry, fsn_entry); + dn_mark = container_of(inode_mark, struct dnotify_mark, fsn_mark); - spin_lock(&entry->lock); - prev = &dnentry->dn; + spin_lock(&inode_mark->lock); + prev = &dn_mark->dn; while ((dn = *prev) != NULL) { if ((dn->dn_mask & test_mask) == 0) { prev = &dn->dn_next; @@ -118,120 +116,78 @@ static int dnotify_handle_event(struct fsnotify_group *group, else { *prev = dn->dn_next; kmem_cache_free(dnotify_struct_cache, dn); - dnotify_recalc_inode_mask(entry); + dnotify_recalc_inode_mask(inode_mark); } } - spin_unlock(&entry->lock); - fsnotify_put_mark(entry); + spin_unlock(&inode_mark->lock); return 0; } -/* - * Given an inode and mask determine if dnotify would be interested in sending - * userspace notification for that pair. - */ -static bool dnotify_should_send_event(struct fsnotify_group *group, - struct inode *inode, __u32 mask) +static void dnotify_free_mark(struct fsnotify_mark *fsn_mark) { - struct fsnotify_mark_entry *entry; - bool send; - - /* !dir_notify_enable should never get here, don't waste time checking - if (!dir_notify_enable) - return 0; */ - - /* not a dir, dnotify doesn't care */ - if (!S_ISDIR(inode->i_mode)) - return false; - - spin_lock(&inode->i_lock); - entry = fsnotify_find_mark_entry(group, inode); - spin_unlock(&inode->i_lock); + struct dnotify_mark *dn_mark = container_of(fsn_mark, + struct dnotify_mark, + fsn_mark); - /* no mark means no dnotify watch */ - if (!entry) - return false; + BUG_ON(dn_mark->dn); - mask = (mask & ~FS_EVENT_ON_CHILD); - send = (mask & entry->mask); - - fsnotify_put_mark(entry); /* matches fsnotify_find_mark_entry */ - - return send; -} - -static void dnotify_free_mark(struct fsnotify_mark_entry *entry) -{ - struct dnotify_mark_entry *dnentry = container_of(entry, - struct dnotify_mark_entry, - fsn_entry); - - BUG_ON(dnentry->dn); - - kmem_cache_free(dnotify_mark_entry_cache, dnentry); + kmem_cache_free(dnotify_mark_cache, dn_mark); } static struct fsnotify_ops dnotify_fsnotify_ops = { .handle_event = dnotify_handle_event, - .should_send_event = dnotify_should_send_event, - .free_group_priv = NULL, - .freeing_mark = NULL, - .free_event_priv = NULL, }; /* * Called every time a file is closed. Looks first for a dnotify mark on the - * inode. If one is found run all of the ->dn entries attached to that + * inode. If one is found run all of the ->dn structures attached to that * mark for one relevant to this process closing the file and remove that * dnotify_struct. If that was the last dnotify_struct also remove the - * fsnotify_mark_entry. + * fsnotify_mark. */ void dnotify_flush(struct file *filp, fl_owner_t id) { - struct fsnotify_mark_entry *entry; - struct dnotify_mark_entry *dnentry; + struct fsnotify_mark *fsn_mark; + struct dnotify_mark *dn_mark; struct dnotify_struct *dn; struct dnotify_struct **prev; struct inode *inode; - inode = filp->f_path.dentry->d_inode; + inode = file_inode(filp); if (!S_ISDIR(inode->i_mode)) return; - spin_lock(&inode->i_lock); - entry = fsnotify_find_mark_entry(dnotify_group, inode); - spin_unlock(&inode->i_lock); - if (!entry) + fsn_mark = fsnotify_find_inode_mark(dnotify_group, inode); + if (!fsn_mark) return; - dnentry = container_of(entry, struct dnotify_mark_entry, fsn_entry); + dn_mark = container_of(fsn_mark, struct dnotify_mark, fsn_mark); - mutex_lock(&dnotify_mark_mutex); + mutex_lock(&dnotify_group->mark_mutex); - spin_lock(&entry->lock); - prev = &dnentry->dn; + spin_lock(&fsn_mark->lock); + prev = &dn_mark->dn; while ((dn = *prev) != NULL) { if ((dn->dn_owner == id) && (dn->dn_filp == filp)) { *prev = dn->dn_next; kmem_cache_free(dnotify_struct_cache, dn); - dnotify_recalc_inode_mask(entry); + dnotify_recalc_inode_mask(fsn_mark); break; } prev = &dn->dn_next; } - spin_unlock(&entry->lock); - - /* nothing else could have found us thanks to the dnotify_mark_mutex */ - if (dnentry->dn == NULL) - fsnotify_destroy_mark_by_entry(entry); + spin_unlock(&fsn_mark->lock); - fsnotify_recalc_group_mask(dnotify_group); + /* nothing else could have found us thanks to the dnotify_groups + mark_mutex */ + if (dn_mark->dn == NULL) + fsnotify_destroy_mark_locked(fsn_mark, dnotify_group); - mutex_unlock(&dnotify_mark_mutex); + mutex_unlock(&dnotify_group->mark_mutex); - fsnotify_put_mark(entry); + fsnotify_put_mark(fsn_mark); } /* this conversion is done only at watch creation */ @@ -259,16 +215,16 @@ static __u32 convert_arg(unsigned long arg) /* * If multiple processes watch the same inode with dnotify there is only one - * dnotify mark in inode->i_fsnotify_mark_entries but we chain a dnotify_struct + * dnotify mark in inode->i_fsnotify_marks but we chain a dnotify_struct * onto that mark. This function either attaches the new dnotify_struct onto * that list, or it |= the mask onto an existing dnofiy_struct. */ -static int attach_dn(struct dnotify_struct *dn, struct dnotify_mark_entry *dnentry, +static int attach_dn(struct dnotify_struct *dn, struct dnotify_mark *dn_mark, fl_owner_t id, int fd, struct file *filp, __u32 mask) { struct dnotify_struct *odn; - odn = dnentry->dn; + odn = dn_mark->dn; while (odn != NULL) { /* adding more events to existing dnofiy_struct? */ if ((odn->dn_owner == id) && (odn->dn_filp == filp)) { @@ -283,8 +239,8 @@ static int attach_dn(struct dnotify_struct *dn, struct dnotify_mark_entry *dnent dn->dn_fd = fd; dn->dn_filp = filp; dn->dn_owner = id; - dn->dn_next = dnentry->dn; - dnentry->dn = dn; + dn->dn_next = dn_mark->dn; + dn_mark->dn = dn; return 0; } @@ -296,8 +252,8 @@ static int attach_dn(struct dnotify_struct *dn, struct dnotify_mark_entry *dnent */ int fcntl_dirnotify(int fd, struct file *filp, unsigned long arg) { - struct dnotify_mark_entry *new_dnentry, *dnentry; - struct fsnotify_mark_entry *new_entry, *entry; + struct dnotify_mark *new_dn_mark, *dn_mark; + struct fsnotify_mark *new_fsn_mark, *fsn_mark; struct dnotify_struct *dn; struct inode *inode; fl_owner_t id = current->files; @@ -306,7 +262,7 @@ int fcntl_dirnotify(int fd, struct file *filp, unsigned long arg) __u32 mask; /* we use these to tell if we need to kfree */ - new_entry = NULL; + new_fsn_mark = NULL; dn = NULL; if (!dir_notify_enable) { @@ -322,7 +278,7 @@ int fcntl_dirnotify(int fd, struct file *filp, unsigned long arg) } /* dnotify only works on directories */ - inode = filp->f_path.dentry->d_inode; + inode = file_inode(filp); if (!S_ISDIR(inode->i_mode)) { error = -ENOTDIR; goto out_err; @@ -336,8 +292,8 @@ int fcntl_dirnotify(int fd, struct file *filp, unsigned long arg) } /* new fsnotify mark, we expect most fcntl calls to add a new mark */ - new_dnentry = kmem_cache_alloc(dnotify_mark_entry_cache, GFP_KERNEL); - if (!new_dnentry) { + new_dn_mark = kmem_cache_alloc(dnotify_mark_cache, GFP_KERNEL); + if (!new_dn_mark) { error = -ENOMEM; goto out_err; } @@ -345,29 +301,28 @@ int fcntl_dirnotify(int fd, struct file *filp, unsigned long arg) /* convert the userspace DN_* "arg" to the internal FS_* defines in fsnotify */ mask = convert_arg(arg); - /* set up the new_entry and new_dnentry */ - new_entry = &new_dnentry->fsn_entry; - fsnotify_init_mark(new_entry, dnotify_free_mark); - new_entry->mask = mask; - new_dnentry->dn = NULL; + /* set up the new_fsn_mark and new_dn_mark */ + new_fsn_mark = &new_dn_mark->fsn_mark; + fsnotify_init_mark(new_fsn_mark, dnotify_free_mark); + new_fsn_mark->mask = mask; + new_dn_mark->dn = NULL; /* this is needed to prevent the fcntl/close race described below */ - mutex_lock(&dnotify_mark_mutex); - - /* add the new_entry or find an old one. */ - spin_lock(&inode->i_lock); - entry = fsnotify_find_mark_entry(dnotify_group, inode); - spin_unlock(&inode->i_lock); - if (entry) { - dnentry = container_of(entry, struct dnotify_mark_entry, fsn_entry); - spin_lock(&entry->lock); + mutex_lock(&dnotify_group->mark_mutex); + + /* add the new_fsn_mark or find an old one. */ + fsn_mark = fsnotify_find_inode_mark(dnotify_group, inode); + if (fsn_mark) { + dn_mark = container_of(fsn_mark, struct dnotify_mark, fsn_mark); + spin_lock(&fsn_mark->lock); } else { - fsnotify_add_mark(new_entry, dnotify_group, inode); - spin_lock(&new_entry->lock); - entry = new_entry; - dnentry = new_dnentry; - /* we used new_entry, so don't free it */ - new_entry = NULL; + fsnotify_add_mark_locked(new_fsn_mark, dnotify_group, inode, + NULL, 0); + spin_lock(&new_fsn_mark->lock); + fsn_mark = new_fsn_mark; + dn_mark = new_dn_mark; + /* we used new_fsn_mark, so don't free it */ + new_fsn_mark = NULL; } rcu_read_lock(); @@ -376,17 +331,17 @@ int fcntl_dirnotify(int fd, struct file *filp, unsigned long arg) /* if (f != filp) means that we lost a race and another task/thread * actually closed the fd we are still playing with before we grabbed - * the dnotify_mark_mutex and entry->lock. Since closing the fd is the - * only time we clean up the mark entries we need to get our mark off - * the list. */ + * the dnotify_groups mark_mutex and fsn_mark->lock. Since closing the + * fd is the only time we clean up the marks we need to get our mark + * off the list. */ if (f != filp) { /* if we added ourselves, shoot ourselves, it's possible that - * the flush actually did shoot this entry. That's fine too + * the flush actually did shoot this fsn_mark. That's fine too * since multiple calls to destroy_mark is perfectly safe, if - * we found a dnentry already attached to the inode, just sod + * we found a dn_mark already attached to the inode, just sod * off silently as the flush at close time dealt with it. */ - if (dnentry == new_dnentry) + if (dn_mark == new_dn_mark) destroy = 1; goto out; } @@ -394,13 +349,13 @@ int fcntl_dirnotify(int fd, struct file *filp, unsigned long arg) error = __f_setown(filp, task_pid(current), PIDTYPE_PID, 0); if (error) { /* if we added, we must shoot */ - if (dnentry == new_dnentry) + if (dn_mark == new_dn_mark) destroy = 1; goto out; } - error = attach_dn(dn, dnentry, id, fd, filp, mask); - /* !error means that we attached the dn to the dnentry, so don't free it */ + error = attach_dn(dn, dn_mark, id, fd, filp, mask); + /* !error means that we attached the dn to the dn_mark, so don't free it */ if (!error) dn = NULL; /* -EEXIST means that we didn't add this new dn and used an old one. @@ -408,20 +363,18 @@ int fcntl_dirnotify(int fd, struct file *filp, unsigned long arg) else if (error == -EEXIST) error = 0; - dnotify_recalc_inode_mask(entry); + dnotify_recalc_inode_mask(fsn_mark); out: - spin_unlock(&entry->lock); + spin_unlock(&fsn_mark->lock); if (destroy) - fsnotify_destroy_mark_by_entry(entry); - - fsnotify_recalc_group_mask(dnotify_group); + fsnotify_destroy_mark_locked(fsn_mark, dnotify_group); - mutex_unlock(&dnotify_mark_mutex); - fsnotify_put_mark(entry); + mutex_unlock(&dnotify_group->mark_mutex); + fsnotify_put_mark(fsn_mark); out_err: - if (new_entry) - fsnotify_put_mark(new_entry); + if (new_fsn_mark) + fsnotify_put_mark(new_fsn_mark); if (dn) kmem_cache_free(dnotify_struct_cache, dn); return error; @@ -430,10 +383,9 @@ out_err: static int __init dnotify_init(void) { dnotify_struct_cache = KMEM_CACHE(dnotify_struct, SLAB_PANIC); - dnotify_mark_entry_cache = KMEM_CACHE(dnotify_mark_entry, SLAB_PANIC); + dnotify_mark_cache = KMEM_CACHE(dnotify_mark, SLAB_PANIC); - dnotify_group = fsnotify_obtain_group(DNOTIFY_GROUP_NUM, - 0, &dnotify_fsnotify_ops); + dnotify_group = fsnotify_alloc_group(&dnotify_fsnotify_ops); if (IS_ERR(dnotify_group)) panic("unable to allocate fsnotify group for dnotify\n"); return 0; diff --git a/fs/notify/fanotify/Kconfig b/fs/notify/fanotify/Kconfig new file mode 100644 index 00000000000..e5f911bd80d --- /dev/null +++ b/fs/notify/fanotify/Kconfig @@ -0,0 +1,26 @@ +config FANOTIFY + bool "Filesystem wide access notification" + select FSNOTIFY + select ANON_INODES + default n + ---help--- + Say Y here to enable fanotify support. fanotify is a file access + notification system which differs from inotify in that it sends + an open file descriptor to the userspace listener along with + the event. + + If unsure, say Y. + +config FANOTIFY_ACCESS_PERMISSIONS + bool "fanotify permissions checking" + depends on FANOTIFY + depends on SECURITY + default n + ---help--- + Say Y here is you want fanotify listeners to be able to make permissions + decisions concerning filesystem events. This is used by some fanotify + listeners which need to scan files before allowing the system access to + use those files. This is used by some anti-malware vendors and by some + hierarchical storage managent systems. + + If unsure, say N. diff --git a/fs/notify/fanotify/Makefile b/fs/notify/fanotify/Makefile new file mode 100644 index 00000000000..0999213e7e6 --- /dev/null +++ b/fs/notify/fanotify/Makefile @@ -0,0 +1 @@ +obj-$(CONFIG_FANOTIFY) += fanotify.o fanotify_user.o diff --git a/fs/notify/fanotify/fanotify.c b/fs/notify/fanotify/fanotify.c new file mode 100644 index 00000000000..ee9cb3795c2 --- /dev/null +++ b/fs/notify/fanotify/fanotify.c @@ -0,0 +1,262 @@ +#include <linux/fanotify.h> +#include <linux/fdtable.h> +#include <linux/fsnotify_backend.h> +#include <linux/init.h> +#include <linux/jiffies.h> +#include <linux/kernel.h> /* UINT_MAX */ +#include <linux/mount.h> +#include <linux/sched.h> +#include <linux/types.h> +#include <linux/wait.h> + +#include "fanotify.h" + +static bool should_merge(struct fsnotify_event *old_fsn, + struct fsnotify_event *new_fsn) +{ + struct fanotify_event_info *old, *new; + + pr_debug("%s: old=%p new=%p\n", __func__, old_fsn, new_fsn); + old = FANOTIFY_E(old_fsn); + new = FANOTIFY_E(new_fsn); + + if (old_fsn->inode == new_fsn->inode && old->tgid == new->tgid && + old->path.mnt == new->path.mnt && + old->path.dentry == new->path.dentry) + return true; + return false; +} + +/* and the list better be locked by something too! */ +static int fanotify_merge(struct list_head *list, struct fsnotify_event *event) +{ + struct fsnotify_event *test_event; + bool do_merge = false; + + pr_debug("%s: list=%p event=%p\n", __func__, list, event); + +#ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS + /* + * Don't merge a permission event with any other event so that we know + * the event structure we have created in fanotify_handle_event() is the + * one we should check for permission response. + */ + if (event->mask & FAN_ALL_PERM_EVENTS) + return 0; +#endif + + list_for_each_entry_reverse(test_event, list, list) { + if (should_merge(test_event, event)) { + do_merge = true; + break; + } + } + + if (!do_merge) + return 0; + + test_event->mask |= event->mask; + return 1; +} + +#ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS +static int fanotify_get_response(struct fsnotify_group *group, + struct fanotify_perm_event_info *event) +{ + int ret; + + pr_debug("%s: group=%p event=%p\n", __func__, group, event); + + wait_event(group->fanotify_data.access_waitq, event->response || + atomic_read(&group->fanotify_data.bypass_perm)); + + if (!event->response) /* bypass_perm set */ + return 0; + + /* userspace responded, convert to something usable */ + switch (event->response) { + case FAN_ALLOW: + ret = 0; + break; + case FAN_DENY: + default: + ret = -EPERM; + } + event->response = 0; + + pr_debug("%s: group=%p event=%p about to return ret=%d\n", __func__, + group, event, ret); + + return ret; +} +#endif + +static bool fanotify_should_send_event(struct fsnotify_mark *inode_mark, + struct fsnotify_mark *vfsmnt_mark, + u32 event_mask, + void *data, int data_type) +{ + __u32 marks_mask, marks_ignored_mask; + struct path *path = data; + + pr_debug("%s: inode_mark=%p vfsmnt_mark=%p mask=%x data=%p" + " data_type=%d\n", __func__, inode_mark, vfsmnt_mark, + event_mask, data, data_type); + + /* if we don't have enough info to send an event to userspace say no */ + if (data_type != FSNOTIFY_EVENT_PATH) + return false; + + /* sorry, fanotify only gives a damn about files and dirs */ + if (!S_ISREG(path->dentry->d_inode->i_mode) && + !S_ISDIR(path->dentry->d_inode->i_mode)) + return false; + + if (inode_mark && vfsmnt_mark) { + marks_mask = (vfsmnt_mark->mask | inode_mark->mask); + marks_ignored_mask = (vfsmnt_mark->ignored_mask | inode_mark->ignored_mask); + } else if (inode_mark) { + /* + * if the event is for a child and this inode doesn't care about + * events on the child, don't send it! + */ + if ((event_mask & FS_EVENT_ON_CHILD) && + !(inode_mark->mask & FS_EVENT_ON_CHILD)) + return false; + marks_mask = inode_mark->mask; + marks_ignored_mask = inode_mark->ignored_mask; + } else if (vfsmnt_mark) { + marks_mask = vfsmnt_mark->mask; + marks_ignored_mask = vfsmnt_mark->ignored_mask; + } else { + BUG(); + } + + if (S_ISDIR(path->dentry->d_inode->i_mode) && + (marks_ignored_mask & FS_ISDIR)) + return false; + + if (event_mask & marks_mask & ~marks_ignored_mask) + return true; + + return false; +} + +struct fanotify_event_info *fanotify_alloc_event(struct inode *inode, u32 mask, + struct path *path) +{ + struct fanotify_event_info *event; + +#ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS + if (mask & FAN_ALL_PERM_EVENTS) { + struct fanotify_perm_event_info *pevent; + + pevent = kmem_cache_alloc(fanotify_perm_event_cachep, + GFP_KERNEL); + if (!pevent) + return NULL; + event = &pevent->fae; + pevent->response = 0; + goto init; + } +#endif + event = kmem_cache_alloc(fanotify_event_cachep, GFP_KERNEL); + if (!event) + return NULL; +init: __maybe_unused + fsnotify_init_event(&event->fse, inode, mask); + event->tgid = get_pid(task_tgid(current)); + if (path) { + event->path = *path; + path_get(&event->path); + } else { + event->path.mnt = NULL; + event->path.dentry = NULL; + } + return event; +} + +static int fanotify_handle_event(struct fsnotify_group *group, + struct inode *inode, + struct fsnotify_mark *inode_mark, + struct fsnotify_mark *fanotify_mark, + u32 mask, void *data, int data_type, + const unsigned char *file_name, u32 cookie) +{ + int ret = 0; + struct fanotify_event_info *event; + struct fsnotify_event *fsn_event; + + BUILD_BUG_ON(FAN_ACCESS != FS_ACCESS); + BUILD_BUG_ON(FAN_MODIFY != FS_MODIFY); + BUILD_BUG_ON(FAN_CLOSE_NOWRITE != FS_CLOSE_NOWRITE); + BUILD_BUG_ON(FAN_CLOSE_WRITE != FS_CLOSE_WRITE); + BUILD_BUG_ON(FAN_OPEN != FS_OPEN); + BUILD_BUG_ON(FAN_EVENT_ON_CHILD != FS_EVENT_ON_CHILD); + BUILD_BUG_ON(FAN_Q_OVERFLOW != FS_Q_OVERFLOW); + BUILD_BUG_ON(FAN_OPEN_PERM != FS_OPEN_PERM); + BUILD_BUG_ON(FAN_ACCESS_PERM != FS_ACCESS_PERM); + BUILD_BUG_ON(FAN_ONDIR != FS_ISDIR); + + if (!fanotify_should_send_event(inode_mark, fanotify_mark, mask, data, + data_type)) + return 0; + + pr_debug("%s: group=%p inode=%p mask=%x\n", __func__, group, inode, + mask); + + event = fanotify_alloc_event(inode, mask, data); + if (unlikely(!event)) + return -ENOMEM; + + fsn_event = &event->fse; + ret = fsnotify_add_notify_event(group, fsn_event, fanotify_merge); + if (ret) { + /* Permission events shouldn't be merged */ + BUG_ON(ret == 1 && mask & FAN_ALL_PERM_EVENTS); + /* Our event wasn't used in the end. Free it. */ + fsnotify_destroy_event(group, fsn_event); + + return 0; + } + +#ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS + if (mask & FAN_ALL_PERM_EVENTS) { + ret = fanotify_get_response(group, FANOTIFY_PE(fsn_event)); + fsnotify_destroy_event(group, fsn_event); + } +#endif + return ret; +} + +static void fanotify_free_group_priv(struct fsnotify_group *group) +{ + struct user_struct *user; + + user = group->fanotify_data.user; + atomic_dec(&user->fanotify_listeners); + free_uid(user); +} + +static void fanotify_free_event(struct fsnotify_event *fsn_event) +{ + struct fanotify_event_info *event; + + event = FANOTIFY_E(fsn_event); + path_put(&event->path); + put_pid(event->tgid); +#ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS + if (fsn_event->mask & FAN_ALL_PERM_EVENTS) { + kmem_cache_free(fanotify_perm_event_cachep, + FANOTIFY_PE(fsn_event)); + return; + } +#endif + kmem_cache_free(fanotify_event_cachep, event); +} + +const struct fsnotify_ops fanotify_fsnotify_ops = { + .handle_event = fanotify_handle_event, + .free_group_priv = fanotify_free_group_priv, + .free_event = fanotify_free_event, +}; diff --git a/fs/notify/fanotify/fanotify.h b/fs/notify/fanotify/fanotify.h new file mode 100644 index 00000000000..2a5fb14115d --- /dev/null +++ b/fs/notify/fanotify/fanotify.h @@ -0,0 +1,50 @@ +#include <linux/fsnotify_backend.h> +#include <linux/path.h> +#include <linux/slab.h> + +extern struct kmem_cache *fanotify_event_cachep; +extern struct kmem_cache *fanotify_perm_event_cachep; + +/* + * Structure for normal fanotify events. It gets allocated in + * fanotify_handle_event() and freed when the information is retrieved by + * userspace + */ +struct fanotify_event_info { + struct fsnotify_event fse; + /* + * We hold ref to this path so it may be dereferenced at any point + * during this object's lifetime + */ + struct path path; + struct pid *tgid; +}; + +#ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS +/* + * Structure for permission fanotify events. It gets allocated and freed in + * fanotify_handle_event() since we wait there for user response. When the + * information is retrieved by userspace the structure is moved from + * group->notification_list to group->fanotify_data.access_list to wait for + * user response. + */ +struct fanotify_perm_event_info { + struct fanotify_event_info fae; + int response; /* userspace answer to question */ + int fd; /* fd we passed to userspace for this event */ +}; + +static inline struct fanotify_perm_event_info * +FANOTIFY_PE(struct fsnotify_event *fse) +{ + return container_of(fse, struct fanotify_perm_event_info, fae.fse); +} +#endif + +static inline struct fanotify_event_info *FANOTIFY_E(struct fsnotify_event *fse) +{ + return container_of(fse, struct fanotify_event_info, fse); +} + +struct fanotify_event_info *fanotify_alloc_event(struct inode *inode, u32 mask, + struct path *path); diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c new file mode 100644 index 00000000000..3fdc8a3e113 --- /dev/null +++ b/fs/notify/fanotify/fanotify_user.c @@ -0,0 +1,919 @@ +#include <linux/fanotify.h> +#include <linux/fcntl.h> +#include <linux/file.h> +#include <linux/fs.h> +#include <linux/anon_inodes.h> +#include <linux/fsnotify_backend.h> +#include <linux/init.h> +#include <linux/mount.h> +#include <linux/namei.h> +#include <linux/poll.h> +#include <linux/security.h> +#include <linux/syscalls.h> +#include <linux/slab.h> +#include <linux/types.h> +#include <linux/uaccess.h> +#include <linux/compat.h> + +#include <asm/ioctls.h> + +#include "../../mount.h" +#include "../fdinfo.h" +#include "fanotify.h" + +#define FANOTIFY_DEFAULT_MAX_EVENTS 16384 +#define FANOTIFY_DEFAULT_MAX_MARKS 8192 +#define FANOTIFY_DEFAULT_MAX_LISTENERS 128 + +/* + * All flags that may be specified in parameter event_f_flags of fanotify_init. + * + * Internal and external open flags are stored together in field f_flags of + * struct file. Only external open flags shall be allowed in event_f_flags. + * Internal flags like FMODE_NONOTIFY, FMODE_EXEC, FMODE_NOCMTIME shall be + * excluded. + */ +#define FANOTIFY_INIT_ALL_EVENT_F_BITS ( \ + O_ACCMODE | O_APPEND | O_NONBLOCK | \ + __O_SYNC | O_DSYNC | O_CLOEXEC | \ + O_LARGEFILE | O_NOATIME ) + +extern const struct fsnotify_ops fanotify_fsnotify_ops; + +static struct kmem_cache *fanotify_mark_cache __read_mostly; +struct kmem_cache *fanotify_event_cachep __read_mostly; +struct kmem_cache *fanotify_perm_event_cachep __read_mostly; + +/* + * Get an fsnotify notification event if one exists and is small + * enough to fit in "count". Return an error pointer if the count + * is not large enough. + * + * Called with the group->notification_mutex held. + */ +static struct fsnotify_event *get_one_event(struct fsnotify_group *group, + size_t count) +{ + BUG_ON(!mutex_is_locked(&group->notification_mutex)); + + pr_debug("%s: group=%p count=%zd\n", __func__, group, count); + + if (fsnotify_notify_queue_is_empty(group)) + return NULL; + + if (FAN_EVENT_METADATA_LEN > count) + return ERR_PTR(-EINVAL); + + /* held the notification_mutex the whole time, so this is the + * same event we peeked above */ + return fsnotify_remove_notify_event(group); +} + +static int create_fd(struct fsnotify_group *group, + struct fanotify_event_info *event, + struct file **file) +{ + int client_fd; + struct file *new_file; + + pr_debug("%s: group=%p event=%p\n", __func__, group, event); + + client_fd = get_unused_fd(); + if (client_fd < 0) + return client_fd; + + /* + * we need a new file handle for the userspace program so it can read even if it was + * originally opened O_WRONLY. + */ + /* it's possible this event was an overflow event. in that case dentry and mnt + * are NULL; That's fine, just don't call dentry open */ + if (event->path.dentry && event->path.mnt) + new_file = dentry_open(&event->path, + group->fanotify_data.f_flags | FMODE_NONOTIFY, + current_cred()); + else + new_file = ERR_PTR(-EOVERFLOW); + if (IS_ERR(new_file)) { + /* + * we still send an event even if we can't open the file. this + * can happen when say tasks are gone and we try to open their + * /proc files or we try to open a WRONLY file like in sysfs + * we just send the errno to userspace since there isn't much + * else we can do. + */ + put_unused_fd(client_fd); + client_fd = PTR_ERR(new_file); + } else { + *file = new_file; + } + + return client_fd; +} + +static int fill_event_metadata(struct fsnotify_group *group, + struct fanotify_event_metadata *metadata, + struct fsnotify_event *fsn_event, + struct file **file) +{ + int ret = 0; + struct fanotify_event_info *event; + + pr_debug("%s: group=%p metadata=%p event=%p\n", __func__, + group, metadata, fsn_event); + + *file = NULL; + event = container_of(fsn_event, struct fanotify_event_info, fse); + metadata->event_len = FAN_EVENT_METADATA_LEN; + metadata->metadata_len = FAN_EVENT_METADATA_LEN; + metadata->vers = FANOTIFY_METADATA_VERSION; + metadata->reserved = 0; + metadata->mask = fsn_event->mask & FAN_ALL_OUTGOING_EVENTS; + metadata->pid = pid_vnr(event->tgid); + if (unlikely(fsn_event->mask & FAN_Q_OVERFLOW)) + metadata->fd = FAN_NOFD; + else { + metadata->fd = create_fd(group, event, file); + if (metadata->fd < 0) + ret = metadata->fd; + } + + return ret; +} + +#ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS +static struct fanotify_perm_event_info *dequeue_event( + struct fsnotify_group *group, int fd) +{ + struct fanotify_perm_event_info *event, *return_e = NULL; + + spin_lock(&group->fanotify_data.access_lock); + list_for_each_entry(event, &group->fanotify_data.access_list, + fae.fse.list) { + if (event->fd != fd) + continue; + + list_del_init(&event->fae.fse.list); + return_e = event; + break; + } + spin_unlock(&group->fanotify_data.access_lock); + + pr_debug("%s: found return_re=%p\n", __func__, return_e); + + return return_e; +} + +static int process_access_response(struct fsnotify_group *group, + struct fanotify_response *response_struct) +{ + struct fanotify_perm_event_info *event; + int fd = response_struct->fd; + int response = response_struct->response; + + pr_debug("%s: group=%p fd=%d response=%d\n", __func__, group, + fd, response); + /* + * make sure the response is valid, if invalid we do nothing and either + * userspace can send a valid response or we will clean it up after the + * timeout + */ + switch (response) { + case FAN_ALLOW: + case FAN_DENY: + break; + default: + return -EINVAL; + } + + if (fd < 0) + return -EINVAL; + + event = dequeue_event(group, fd); + if (!event) + return -ENOENT; + + event->response = response; + wake_up(&group->fanotify_data.access_waitq); + + return 0; +} +#endif + +static ssize_t copy_event_to_user(struct fsnotify_group *group, + struct fsnotify_event *event, + char __user *buf) +{ + struct fanotify_event_metadata fanotify_event_metadata; + struct file *f; + int fd, ret; + + pr_debug("%s: group=%p event=%p\n", __func__, group, event); + + ret = fill_event_metadata(group, &fanotify_event_metadata, event, &f); + if (ret < 0) + return ret; + + fd = fanotify_event_metadata.fd; + ret = -EFAULT; + if (copy_to_user(buf, &fanotify_event_metadata, + fanotify_event_metadata.event_len)) + goto out_close_fd; + +#ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS + if (event->mask & FAN_ALL_PERM_EVENTS) + FANOTIFY_PE(event)->fd = fd; +#endif + + if (fd != FAN_NOFD) + fd_install(fd, f); + return fanotify_event_metadata.event_len; + +out_close_fd: + if (fd != FAN_NOFD) { + put_unused_fd(fd); + fput(f); + } + return ret; +} + +/* intofiy userspace file descriptor functions */ +static unsigned int fanotify_poll(struct file *file, poll_table *wait) +{ + struct fsnotify_group *group = file->private_data; + int ret = 0; + + poll_wait(file, &group->notification_waitq, wait); + mutex_lock(&group->notification_mutex); + if (!fsnotify_notify_queue_is_empty(group)) + ret = POLLIN | POLLRDNORM; + mutex_unlock(&group->notification_mutex); + + return ret; +} + +static ssize_t fanotify_read(struct file *file, char __user *buf, + size_t count, loff_t *pos) +{ + struct fsnotify_group *group; + struct fsnotify_event *kevent; + char __user *start; + int ret; + DEFINE_WAIT(wait); + + start = buf; + group = file->private_data; + + pr_debug("%s: group=%p\n", __func__, group); + + while (1) { + prepare_to_wait(&group->notification_waitq, &wait, TASK_INTERRUPTIBLE); + + mutex_lock(&group->notification_mutex); + kevent = get_one_event(group, count); + mutex_unlock(&group->notification_mutex); + + if (IS_ERR(kevent)) { + ret = PTR_ERR(kevent); + break; + } + + if (!kevent) { + ret = -EAGAIN; + if (file->f_flags & O_NONBLOCK) + break; + + ret = -ERESTARTSYS; + if (signal_pending(current)) + break; + + if (start != buf) + break; + schedule(); + continue; + } + + ret = copy_event_to_user(group, kevent, buf); + /* + * Permission events get queued to wait for response. Other + * events can be destroyed now. + */ + if (!(kevent->mask & FAN_ALL_PERM_EVENTS)) { + fsnotify_destroy_event(group, kevent); + if (ret < 0) + break; + } else { +#ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS + if (ret < 0) { + FANOTIFY_PE(kevent)->response = FAN_DENY; + wake_up(&group->fanotify_data.access_waitq); + break; + } + spin_lock(&group->fanotify_data.access_lock); + list_add_tail(&kevent->list, + &group->fanotify_data.access_list); + spin_unlock(&group->fanotify_data.access_lock); +#endif + } + buf += ret; + count -= ret; + } + + finish_wait(&group->notification_waitq, &wait); + if (start != buf && ret != -EFAULT) + ret = buf - start; + return ret; +} + +static ssize_t fanotify_write(struct file *file, const char __user *buf, size_t count, loff_t *pos) +{ +#ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS + struct fanotify_response response = { .fd = -1, .response = -1 }; + struct fsnotify_group *group; + int ret; + + group = file->private_data; + + if (count > sizeof(response)) + count = sizeof(response); + + pr_debug("%s: group=%p count=%zu\n", __func__, group, count); + + if (copy_from_user(&response, buf, count)) + return -EFAULT; + + ret = process_access_response(group, &response); + if (ret < 0) + count = ret; + + return count; +#else + return -EINVAL; +#endif +} + +static int fanotify_release(struct inode *ignored, struct file *file) +{ + struct fsnotify_group *group = file->private_data; + +#ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS + struct fanotify_perm_event_info *event, *next; + + spin_lock(&group->fanotify_data.access_lock); + + atomic_inc(&group->fanotify_data.bypass_perm); + + list_for_each_entry_safe(event, next, &group->fanotify_data.access_list, + fae.fse.list) { + pr_debug("%s: found group=%p event=%p\n", __func__, group, + event); + + list_del_init(&event->fae.fse.list); + event->response = FAN_ALLOW; + } + spin_unlock(&group->fanotify_data.access_lock); + + wake_up(&group->fanotify_data.access_waitq); +#endif + + /* matches the fanotify_init->fsnotify_alloc_group */ + fsnotify_destroy_group(group); + + return 0; +} + +static long fanotify_ioctl(struct file *file, unsigned int cmd, unsigned long arg) +{ + struct fsnotify_group *group; + struct fsnotify_event *fsn_event; + void __user *p; + int ret = -ENOTTY; + size_t send_len = 0; + + group = file->private_data; + + p = (void __user *) arg; + + switch (cmd) { + case FIONREAD: + mutex_lock(&group->notification_mutex); + list_for_each_entry(fsn_event, &group->notification_list, list) + send_len += FAN_EVENT_METADATA_LEN; + mutex_unlock(&group->notification_mutex); + ret = put_user(send_len, (int __user *) p); + break; + } + + return ret; +} + +static const struct file_operations fanotify_fops = { + .show_fdinfo = fanotify_show_fdinfo, + .poll = fanotify_poll, + .read = fanotify_read, + .write = fanotify_write, + .fasync = NULL, + .release = fanotify_release, + .unlocked_ioctl = fanotify_ioctl, + .compat_ioctl = fanotify_ioctl, + .llseek = noop_llseek, +}; + +static void fanotify_free_mark(struct fsnotify_mark *fsn_mark) +{ + kmem_cache_free(fanotify_mark_cache, fsn_mark); +} + +static int fanotify_find_path(int dfd, const char __user *filename, + struct path *path, unsigned int flags) +{ + int ret; + + pr_debug("%s: dfd=%d filename=%p flags=%x\n", __func__, + dfd, filename, flags); + + if (filename == NULL) { + struct fd f = fdget(dfd); + + ret = -EBADF; + if (!f.file) + goto out; + + ret = -ENOTDIR; + if ((flags & FAN_MARK_ONLYDIR) && + !(S_ISDIR(file_inode(f.file)->i_mode))) { + fdput(f); + goto out; + } + + *path = f.file->f_path; + path_get(path); + fdput(f); + } else { + unsigned int lookup_flags = 0; + + if (!(flags & FAN_MARK_DONT_FOLLOW)) + lookup_flags |= LOOKUP_FOLLOW; + if (flags & FAN_MARK_ONLYDIR) + lookup_flags |= LOOKUP_DIRECTORY; + + ret = user_path_at(dfd, filename, lookup_flags, path); + if (ret) + goto out; + } + + /* you can only watch an inode if you have read permissions on it */ + ret = inode_permission(path->dentry->d_inode, MAY_READ); + if (ret) + path_put(path); +out: + return ret; +} + +static __u32 fanotify_mark_remove_from_mask(struct fsnotify_mark *fsn_mark, + __u32 mask, + unsigned int flags, + int *destroy) +{ + __u32 oldmask; + + spin_lock(&fsn_mark->lock); + if (!(flags & FAN_MARK_IGNORED_MASK)) { + oldmask = fsn_mark->mask; + fsnotify_set_mark_mask_locked(fsn_mark, (oldmask & ~mask)); + } else { + oldmask = fsn_mark->ignored_mask; + fsnotify_set_mark_ignored_mask_locked(fsn_mark, (oldmask & ~mask)); + } + spin_unlock(&fsn_mark->lock); + + *destroy = !(oldmask & ~mask); + + return mask & oldmask; +} + +static int fanotify_remove_vfsmount_mark(struct fsnotify_group *group, + struct vfsmount *mnt, __u32 mask, + unsigned int flags) +{ + struct fsnotify_mark *fsn_mark = NULL; + __u32 removed; + int destroy_mark; + + mutex_lock(&group->mark_mutex); + fsn_mark = fsnotify_find_vfsmount_mark(group, mnt); + if (!fsn_mark) { + mutex_unlock(&group->mark_mutex); + return -ENOENT; + } + + removed = fanotify_mark_remove_from_mask(fsn_mark, mask, flags, + &destroy_mark); + if (destroy_mark) + fsnotify_destroy_mark_locked(fsn_mark, group); + mutex_unlock(&group->mark_mutex); + + fsnotify_put_mark(fsn_mark); + if (removed & real_mount(mnt)->mnt_fsnotify_mask) + fsnotify_recalc_vfsmount_mask(mnt); + + return 0; +} + +static int fanotify_remove_inode_mark(struct fsnotify_group *group, + struct inode *inode, __u32 mask, + unsigned int flags) +{ + struct fsnotify_mark *fsn_mark = NULL; + __u32 removed; + int destroy_mark; + + mutex_lock(&group->mark_mutex); + fsn_mark = fsnotify_find_inode_mark(group, inode); + if (!fsn_mark) { + mutex_unlock(&group->mark_mutex); + return -ENOENT; + } + + removed = fanotify_mark_remove_from_mask(fsn_mark, mask, flags, + &destroy_mark); + if (destroy_mark) + fsnotify_destroy_mark_locked(fsn_mark, group); + mutex_unlock(&group->mark_mutex); + + /* matches the fsnotify_find_inode_mark() */ + fsnotify_put_mark(fsn_mark); + if (removed & inode->i_fsnotify_mask) + fsnotify_recalc_inode_mask(inode); + + return 0; +} + +static __u32 fanotify_mark_add_to_mask(struct fsnotify_mark *fsn_mark, + __u32 mask, + unsigned int flags) +{ + __u32 oldmask = -1; + + spin_lock(&fsn_mark->lock); + if (!(flags & FAN_MARK_IGNORED_MASK)) { + oldmask = fsn_mark->mask; + fsnotify_set_mark_mask_locked(fsn_mark, (oldmask | mask)); + } else { + __u32 tmask = fsn_mark->ignored_mask | mask; + fsnotify_set_mark_ignored_mask_locked(fsn_mark, tmask); + if (flags & FAN_MARK_IGNORED_SURV_MODIFY) + fsn_mark->flags |= FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY; + } + + if (!(flags & FAN_MARK_ONDIR)) { + __u32 tmask = fsn_mark->ignored_mask | FAN_ONDIR; + fsnotify_set_mark_ignored_mask_locked(fsn_mark, tmask); + } + + spin_unlock(&fsn_mark->lock); + + return mask & ~oldmask; +} + +static struct fsnotify_mark *fanotify_add_new_mark(struct fsnotify_group *group, + struct inode *inode, + struct vfsmount *mnt) +{ + struct fsnotify_mark *mark; + int ret; + + if (atomic_read(&group->num_marks) > group->fanotify_data.max_marks) + return ERR_PTR(-ENOSPC); + + mark = kmem_cache_alloc(fanotify_mark_cache, GFP_KERNEL); + if (!mark) + return ERR_PTR(-ENOMEM); + + fsnotify_init_mark(mark, fanotify_free_mark); + ret = fsnotify_add_mark_locked(mark, group, inode, mnt, 0); + if (ret) { + fsnotify_put_mark(mark); + return ERR_PTR(ret); + } + + return mark; +} + + +static int fanotify_add_vfsmount_mark(struct fsnotify_group *group, + struct vfsmount *mnt, __u32 mask, + unsigned int flags) +{ + struct fsnotify_mark *fsn_mark; + __u32 added; + + mutex_lock(&group->mark_mutex); + fsn_mark = fsnotify_find_vfsmount_mark(group, mnt); + if (!fsn_mark) { + fsn_mark = fanotify_add_new_mark(group, NULL, mnt); + if (IS_ERR(fsn_mark)) { + mutex_unlock(&group->mark_mutex); + return PTR_ERR(fsn_mark); + } + } + added = fanotify_mark_add_to_mask(fsn_mark, mask, flags); + mutex_unlock(&group->mark_mutex); + + if (added & ~real_mount(mnt)->mnt_fsnotify_mask) + fsnotify_recalc_vfsmount_mask(mnt); + + fsnotify_put_mark(fsn_mark); + return 0; +} + +static int fanotify_add_inode_mark(struct fsnotify_group *group, + struct inode *inode, __u32 mask, + unsigned int flags) +{ + struct fsnotify_mark *fsn_mark; + __u32 added; + + pr_debug("%s: group=%p inode=%p\n", __func__, group, inode); + + /* + * If some other task has this inode open for write we should not add + * an ignored mark, unless that ignored mark is supposed to survive + * modification changes anyway. + */ + if ((flags & FAN_MARK_IGNORED_MASK) && + !(flags & FAN_MARK_IGNORED_SURV_MODIFY) && + (atomic_read(&inode->i_writecount) > 0)) + return 0; + + mutex_lock(&group->mark_mutex); + fsn_mark = fsnotify_find_inode_mark(group, inode); + if (!fsn_mark) { + fsn_mark = fanotify_add_new_mark(group, inode, NULL); + if (IS_ERR(fsn_mark)) { + mutex_unlock(&group->mark_mutex); + return PTR_ERR(fsn_mark); + } + } + added = fanotify_mark_add_to_mask(fsn_mark, mask, flags); + mutex_unlock(&group->mark_mutex); + + if (added & ~inode->i_fsnotify_mask) + fsnotify_recalc_inode_mask(inode); + + fsnotify_put_mark(fsn_mark); + return 0; +} + +/* fanotify syscalls */ +SYSCALL_DEFINE2(fanotify_init, unsigned int, flags, unsigned int, event_f_flags) +{ + struct fsnotify_group *group; + int f_flags, fd; + struct user_struct *user; + struct fanotify_event_info *oevent; + + pr_debug("%s: flags=%d event_f_flags=%d\n", + __func__, flags, event_f_flags); + + if (!capable(CAP_SYS_ADMIN)) + return -EPERM; + + if (flags & ~FAN_ALL_INIT_FLAGS) + return -EINVAL; + + if (event_f_flags & ~FANOTIFY_INIT_ALL_EVENT_F_BITS) + return -EINVAL; + + switch (event_f_flags & O_ACCMODE) { + case O_RDONLY: + case O_RDWR: + case O_WRONLY: + break; + default: + return -EINVAL; + } + + user = get_current_user(); + if (atomic_read(&user->fanotify_listeners) > FANOTIFY_DEFAULT_MAX_LISTENERS) { + free_uid(user); + return -EMFILE; + } + + f_flags = O_RDWR | FMODE_NONOTIFY; + if (flags & FAN_CLOEXEC) + f_flags |= O_CLOEXEC; + if (flags & FAN_NONBLOCK) + f_flags |= O_NONBLOCK; + + /* fsnotify_alloc_group takes a ref. Dropped in fanotify_release */ + group = fsnotify_alloc_group(&fanotify_fsnotify_ops); + if (IS_ERR(group)) { + free_uid(user); + return PTR_ERR(group); + } + + group->fanotify_data.user = user; + atomic_inc(&user->fanotify_listeners); + + oevent = fanotify_alloc_event(NULL, FS_Q_OVERFLOW, NULL); + if (unlikely(!oevent)) { + fd = -ENOMEM; + goto out_destroy_group; + } + group->overflow_event = &oevent->fse; + + if (force_o_largefile()) + event_f_flags |= O_LARGEFILE; + group->fanotify_data.f_flags = event_f_flags; +#ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS + spin_lock_init(&group->fanotify_data.access_lock); + init_waitqueue_head(&group->fanotify_data.access_waitq); + INIT_LIST_HEAD(&group->fanotify_data.access_list); + atomic_set(&group->fanotify_data.bypass_perm, 0); +#endif + switch (flags & FAN_ALL_CLASS_BITS) { + case FAN_CLASS_NOTIF: + group->priority = FS_PRIO_0; + break; + case FAN_CLASS_CONTENT: + group->priority = FS_PRIO_1; + break; + case FAN_CLASS_PRE_CONTENT: + group->priority = FS_PRIO_2; + break; + default: + fd = -EINVAL; + goto out_destroy_group; + } + + if (flags & FAN_UNLIMITED_QUEUE) { + fd = -EPERM; + if (!capable(CAP_SYS_ADMIN)) + goto out_destroy_group; + group->max_events = UINT_MAX; + } else { + group->max_events = FANOTIFY_DEFAULT_MAX_EVENTS; + } + + if (flags & FAN_UNLIMITED_MARKS) { + fd = -EPERM; + if (!capable(CAP_SYS_ADMIN)) + goto out_destroy_group; + group->fanotify_data.max_marks = UINT_MAX; + } else { + group->fanotify_data.max_marks = FANOTIFY_DEFAULT_MAX_MARKS; + } + + fd = anon_inode_getfd("[fanotify]", &fanotify_fops, group, f_flags); + if (fd < 0) + goto out_destroy_group; + + return fd; + +out_destroy_group: + fsnotify_destroy_group(group); + return fd; +} + +SYSCALL_DEFINE5(fanotify_mark, int, fanotify_fd, unsigned int, flags, + __u64, mask, int, dfd, + const char __user *, pathname) +{ + struct inode *inode = NULL; + struct vfsmount *mnt = NULL; + struct fsnotify_group *group; + struct fd f; + struct path path; + int ret; + + pr_debug("%s: fanotify_fd=%d flags=%x dfd=%d pathname=%p mask=%llx\n", + __func__, fanotify_fd, flags, dfd, pathname, mask); + + /* we only use the lower 32 bits as of right now. */ + if (mask & ((__u64)0xffffffff << 32)) + return -EINVAL; + + if (flags & ~FAN_ALL_MARK_FLAGS) + return -EINVAL; + switch (flags & (FAN_MARK_ADD | FAN_MARK_REMOVE | FAN_MARK_FLUSH)) { + case FAN_MARK_ADD: /* fallthrough */ + case FAN_MARK_REMOVE: + if (!mask) + return -EINVAL; + break; + case FAN_MARK_FLUSH: + if (flags & ~(FAN_MARK_MOUNT | FAN_MARK_FLUSH)) + return -EINVAL; + break; + default: + return -EINVAL; + } + + if (mask & FAN_ONDIR) { + flags |= FAN_MARK_ONDIR; + mask &= ~FAN_ONDIR; + } + +#ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS + if (mask & ~(FAN_ALL_EVENTS | FAN_ALL_PERM_EVENTS | FAN_EVENT_ON_CHILD)) +#else + if (mask & ~(FAN_ALL_EVENTS | FAN_EVENT_ON_CHILD)) +#endif + return -EINVAL; + + f = fdget(fanotify_fd); + if (unlikely(!f.file)) + return -EBADF; + + /* verify that this is indeed an fanotify instance */ + ret = -EINVAL; + if (unlikely(f.file->f_op != &fanotify_fops)) + goto fput_and_out; + group = f.file->private_data; + + /* + * group->priority == FS_PRIO_0 == FAN_CLASS_NOTIF. These are not + * allowed to set permissions events. + */ + ret = -EINVAL; + if (mask & FAN_ALL_PERM_EVENTS && + group->priority == FS_PRIO_0) + goto fput_and_out; + + if (flags & FAN_MARK_FLUSH) { + ret = 0; + if (flags & FAN_MARK_MOUNT) + fsnotify_clear_vfsmount_marks_by_group(group); + else + fsnotify_clear_inode_marks_by_group(group); + goto fput_and_out; + } + + ret = fanotify_find_path(dfd, pathname, &path, flags); + if (ret) + goto fput_and_out; + + /* inode held in place by reference to path; group by fget on fd */ + if (!(flags & FAN_MARK_MOUNT)) + inode = path.dentry->d_inode; + else + mnt = path.mnt; + + /* create/update an inode mark */ + switch (flags & (FAN_MARK_ADD | FAN_MARK_REMOVE)) { + case FAN_MARK_ADD: + if (flags & FAN_MARK_MOUNT) + ret = fanotify_add_vfsmount_mark(group, mnt, mask, flags); + else + ret = fanotify_add_inode_mark(group, inode, mask, flags); + break; + case FAN_MARK_REMOVE: + if (flags & FAN_MARK_MOUNT) + ret = fanotify_remove_vfsmount_mark(group, mnt, mask, flags); + else + ret = fanotify_remove_inode_mark(group, inode, mask, flags); + break; + default: + ret = -EINVAL; + } + + path_put(&path); +fput_and_out: + fdput(f); + return ret; +} + +#ifdef CONFIG_COMPAT +COMPAT_SYSCALL_DEFINE6(fanotify_mark, + int, fanotify_fd, unsigned int, flags, + __u32, mask0, __u32, mask1, int, dfd, + const char __user *, pathname) +{ + return sys_fanotify_mark(fanotify_fd, flags, +#ifdef __BIG_ENDIAN + ((__u64)mask0 << 32) | mask1, +#else + ((__u64)mask1 << 32) | mask0, +#endif + dfd, pathname); +} +#endif + +/* + * fanotify_user_setup - Our initialization function. Note that we cannot return + * error because we have compiled-in VFS hooks. So an (unlikely) failure here + * must result in panic(). + */ +static int __init fanotify_user_setup(void) +{ + fanotify_mark_cache = KMEM_CACHE(fsnotify_mark, SLAB_PANIC); + fanotify_event_cachep = KMEM_CACHE(fanotify_event_info, SLAB_PANIC); +#ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS + fanotify_perm_event_cachep = KMEM_CACHE(fanotify_perm_event_info, + SLAB_PANIC); +#endif + + return 0; +} +device_initcall(fanotify_user_setup); diff --git a/fs/notify/fdinfo.c b/fs/notify/fdinfo.c new file mode 100644 index 00000000000..238a5930cb3 --- /dev/null +++ b/fs/notify/fdinfo.c @@ -0,0 +1,179 @@ +#include <linux/file.h> +#include <linux/fs.h> +#include <linux/fsnotify_backend.h> +#include <linux/idr.h> +#include <linux/init.h> +#include <linux/inotify.h> +#include <linux/fanotify.h> +#include <linux/kernel.h> +#include <linux/namei.h> +#include <linux/sched.h> +#include <linux/types.h> +#include <linux/seq_file.h> +#include <linux/proc_fs.h> +#include <linux/exportfs.h> + +#include "inotify/inotify.h" +#include "../fs/mount.h" + +#if defined(CONFIG_PROC_FS) + +#if defined(CONFIG_INOTIFY_USER) || defined(CONFIG_FANOTIFY) + +static int show_fdinfo(struct seq_file *m, struct file *f, + int (*show)(struct seq_file *m, struct fsnotify_mark *mark)) +{ + struct fsnotify_group *group = f->private_data; + struct fsnotify_mark *mark; + int ret = 0; + + mutex_lock(&group->mark_mutex); + list_for_each_entry(mark, &group->marks_list, g_list) { + ret = show(m, mark); + if (ret) + break; + } + mutex_unlock(&group->mark_mutex); + return ret; +} + +#if defined(CONFIG_EXPORTFS) +static int show_mark_fhandle(struct seq_file *m, struct inode *inode) +{ + struct { + struct file_handle handle; + u8 pad[64]; + } f; + int size, ret, i; + + f.handle.handle_bytes = sizeof(f.pad); + size = f.handle.handle_bytes >> 2; + + ret = exportfs_encode_inode_fh(inode, (struct fid *)f.handle.f_handle, &size, 0); + if ((ret == 255) || (ret == -ENOSPC)) { + WARN_ONCE(1, "Can't encode file handler for inotify: %d\n", ret); + return 0; + } + + f.handle.handle_type = ret; + f.handle.handle_bytes = size * sizeof(u32); + + ret = seq_printf(m, "fhandle-bytes:%x fhandle-type:%x f_handle:", + f.handle.handle_bytes, f.handle.handle_type); + + for (i = 0; i < f.handle.handle_bytes; i++) + ret |= seq_printf(m, "%02x", (int)f.handle.f_handle[i]); + + return ret; +} +#else +static int show_mark_fhandle(struct seq_file *m, struct inode *inode) +{ + return 0; +} +#endif + +#ifdef CONFIG_INOTIFY_USER + +static int inotify_fdinfo(struct seq_file *m, struct fsnotify_mark *mark) +{ + struct inotify_inode_mark *inode_mark; + struct inode *inode; + int ret = 0; + + if (!(mark->flags & (FSNOTIFY_MARK_FLAG_ALIVE | FSNOTIFY_MARK_FLAG_INODE))) + return 0; + + inode_mark = container_of(mark, struct inotify_inode_mark, fsn_mark); + inode = igrab(mark->i.inode); + if (inode) { + ret = seq_printf(m, "inotify wd:%x ino:%lx sdev:%x " + "mask:%x ignored_mask:%x ", + inode_mark->wd, inode->i_ino, + inode->i_sb->s_dev, + mark->mask, mark->ignored_mask); + ret |= show_mark_fhandle(m, inode); + ret |= seq_putc(m, '\n'); + iput(inode); + } + + return ret; +} + +int inotify_show_fdinfo(struct seq_file *m, struct file *f) +{ + return show_fdinfo(m, f, inotify_fdinfo); +} + +#endif /* CONFIG_INOTIFY_USER */ + +#ifdef CONFIG_FANOTIFY + +static int fanotify_fdinfo(struct seq_file *m, struct fsnotify_mark *mark) +{ + unsigned int mflags = 0; + struct inode *inode; + int ret = 0; + + if (!(mark->flags & FSNOTIFY_MARK_FLAG_ALIVE)) + return 0; + + if (mark->flags & FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY) + mflags |= FAN_MARK_IGNORED_SURV_MODIFY; + + if (mark->flags & FSNOTIFY_MARK_FLAG_INODE) { + inode = igrab(mark->i.inode); + if (!inode) + goto out; + ret = seq_printf(m, "fanotify ino:%lx sdev:%x " + "mflags:%x mask:%x ignored_mask:%x ", + inode->i_ino, inode->i_sb->s_dev, + mflags, mark->mask, mark->ignored_mask); + ret |= show_mark_fhandle(m, inode); + ret |= seq_putc(m, '\n'); + iput(inode); + } else if (mark->flags & FSNOTIFY_MARK_FLAG_VFSMOUNT) { + struct mount *mnt = real_mount(mark->m.mnt); + + ret = seq_printf(m, "fanotify mnt_id:%x mflags:%x mask:%x " + "ignored_mask:%x\n", mnt->mnt_id, mflags, + mark->mask, mark->ignored_mask); + } +out: + return ret; +} + +int fanotify_show_fdinfo(struct seq_file *m, struct file *f) +{ + struct fsnotify_group *group = f->private_data; + unsigned int flags = 0; + + switch (group->priority) { + case FS_PRIO_0: + flags |= FAN_CLASS_NOTIF; + break; + case FS_PRIO_1: + flags |= FAN_CLASS_CONTENT; + break; + case FS_PRIO_2: + flags |= FAN_CLASS_PRE_CONTENT; + break; + } + + if (group->max_events == UINT_MAX) + flags |= FAN_UNLIMITED_QUEUE; + + if (group->fanotify_data.max_marks == UINT_MAX) + flags |= FAN_UNLIMITED_MARKS; + + seq_printf(m, "fanotify flags:%x event-flags:%x\n", + flags, group->fanotify_data.f_flags); + + return show_fdinfo(m, f, fanotify_fdinfo); +} + +#endif /* CONFIG_FANOTIFY */ + +#endif /* CONFIG_INOTIFY_USER || CONFIG_FANOTIFY */ + +#endif /* CONFIG_PROC_FS */ diff --git a/fs/notify/fdinfo.h b/fs/notify/fdinfo.h new file mode 100644 index 00000000000..556afda990e --- /dev/null +++ b/fs/notify/fdinfo.h @@ -0,0 +1,27 @@ +#ifndef __FSNOTIFY_FDINFO_H__ +#define __FSNOTIFY_FDINFO_H__ + +#include <linux/errno.h> +#include <linux/proc_fs.h> + +struct seq_file; +struct file; + +#ifdef CONFIG_PROC_FS + +#ifdef CONFIG_INOTIFY_USER +extern int inotify_show_fdinfo(struct seq_file *m, struct file *f); +#endif + +#ifdef CONFIG_FANOTIFY +extern int fanotify_show_fdinfo(struct seq_file *m, struct file *f); +#endif + +#else /* CONFIG_PROC_FS */ + +#define inotify_show_fdinfo NULL +#define fanotify_show_fdinfo NULL + +#endif /* CONFIG_PROC_FS */ + +#endif /* __FSNOTIFY_FDINFO_H__ */ diff --git a/fs/notify/fsnotify.c b/fs/notify/fsnotify.c index 037e878e03f..9d3e9c50066 100644 --- a/fs/notify/fsnotify.c +++ b/fs/notify/fsnotify.c @@ -18,12 +18,15 @@ #include <linux/dcache.h> #include <linux/fs.h> +#include <linux/gfp.h> #include <linux/init.h> #include <linux/module.h> +#include <linux/mount.h> #include <linux/srcu.h> #include <linux/fsnotify_backend.h> #include "fsnotify.h" +#include "../mount.h" /* * Clear all of the marks on an inode when it is being evicted from core @@ -34,6 +37,11 @@ void __fsnotify_inode_delete(struct inode *inode) } EXPORT_SYMBOL_GPL(__fsnotify_inode_delete); +void __fsnotify_vfsmount_delete(struct vfsmount *mnt) +{ + fsnotify_clear_marks_by_mount(mnt); +} + /* * Given an inode, first check if we care what happens to our children. Inotify * and dnotify both tell their parents about events. If we care about any event @@ -52,137 +60,234 @@ void __fsnotify_update_child_dentry_flags(struct inode *inode) /* determine if the children should tell inode about their events */ watched = fsnotify_inode_watches_children(inode); - spin_lock(&dcache_lock); + spin_lock(&inode->i_lock); /* run all of the dentries associated with this inode. Since this is a * directory, there damn well better only be one item on this list */ - list_for_each_entry(alias, &inode->i_dentry, d_alias) { + hlist_for_each_entry(alias, &inode->i_dentry, d_alias) { struct dentry *child; /* run all of the children of the original inode and fix their * d_flags to indicate parental interest (their parent is the * original inode) */ + spin_lock(&alias->d_lock); list_for_each_entry(child, &alias->d_subdirs, d_u.d_child) { if (!child->d_inode) continue; - spin_lock(&child->d_lock); + spin_lock_nested(&child->d_lock, DENTRY_D_LOCK_NESTED); if (watched) child->d_flags |= DCACHE_FSNOTIFY_PARENT_WATCHED; else child->d_flags &= ~DCACHE_FSNOTIFY_PARENT_WATCHED; spin_unlock(&child->d_lock); } + spin_unlock(&alias->d_lock); } - spin_unlock(&dcache_lock); + spin_unlock(&inode->i_lock); } /* Notify this dentry's parent about a child's events. */ -void __fsnotify_parent(struct dentry *dentry, __u32 mask) +int __fsnotify_parent(struct path *path, struct dentry *dentry, __u32 mask) { struct dentry *parent; struct inode *p_inode; - bool send = false; - bool should_update_children = false; + int ret = 0; + + if (!dentry) + dentry = path->dentry; if (!(dentry->d_flags & DCACHE_FSNOTIFY_PARENT_WATCHED)) - return; + return 0; - spin_lock(&dentry->d_lock); - parent = dentry->d_parent; + parent = dget_parent(dentry); p_inode = parent->d_inode; - if (fsnotify_inode_watches_children(p_inode)) { - if (p_inode->i_fsnotify_mask & mask) { - dget(parent); - send = true; - } - } else { - /* - * The parent doesn't care about events on it's children but - * at least one child thought it did. We need to run all the - * children and update their d_flags to let them know p_inode - * doesn't care about them any more. - */ - dget(parent); - should_update_children = true; - } - - spin_unlock(&dentry->d_lock); - - if (send) { + if (unlikely(!fsnotify_inode_watches_children(p_inode))) + __fsnotify_update_child_dentry_flags(p_inode); + else if (p_inode->i_fsnotify_mask & mask) { /* we are notifying a parent so come up with the new mask which * specifies these are events which came from a child. */ mask |= FS_EVENT_ON_CHILD; - fsnotify(p_inode, mask, dentry->d_inode, FSNOTIFY_EVENT_INODE, - dentry->d_name.name, 0); - dput(parent); + if (path) + ret = fsnotify(p_inode, mask, path, FSNOTIFY_EVENT_PATH, + dentry->d_name.name, 0); + else + ret = fsnotify(p_inode, mask, dentry->d_inode, FSNOTIFY_EVENT_INODE, + dentry->d_name.name, 0); } - if (unlikely(should_update_children)) { - __fsnotify_update_child_dentry_flags(p_inode); - dput(parent); - } + dput(parent); + + return ret; } EXPORT_SYMBOL_GPL(__fsnotify_parent); +static int send_to_group(struct inode *to_tell, + struct fsnotify_mark *inode_mark, + struct fsnotify_mark *vfsmount_mark, + __u32 mask, void *data, + int data_is, u32 cookie, + const unsigned char *file_name) +{ + struct fsnotify_group *group = NULL; + __u32 inode_test_mask = 0; + __u32 vfsmount_test_mask = 0; + + if (unlikely(!inode_mark && !vfsmount_mark)) { + BUG(); + return 0; + } + + /* clear ignored on inode modification */ + if (mask & FS_MODIFY) { + if (inode_mark && + !(inode_mark->flags & FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY)) + inode_mark->ignored_mask = 0; + if (vfsmount_mark && + !(vfsmount_mark->flags & FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY)) + vfsmount_mark->ignored_mask = 0; + } + + /* does the inode mark tell us to do something? */ + if (inode_mark) { + group = inode_mark->group; + inode_test_mask = (mask & ~FS_EVENT_ON_CHILD); + inode_test_mask &= inode_mark->mask; + inode_test_mask &= ~inode_mark->ignored_mask; + } + + /* does the vfsmount_mark tell us to do something? */ + if (vfsmount_mark) { + vfsmount_test_mask = (mask & ~FS_EVENT_ON_CHILD); + group = vfsmount_mark->group; + vfsmount_test_mask &= vfsmount_mark->mask; + vfsmount_test_mask &= ~vfsmount_mark->ignored_mask; + if (inode_mark) + vfsmount_test_mask &= ~inode_mark->ignored_mask; + } + + pr_debug("%s: group=%p to_tell=%p mask=%x inode_mark=%p" + " inode_test_mask=%x vfsmount_mark=%p vfsmount_test_mask=%x" + " data=%p data_is=%d cookie=%d\n", + __func__, group, to_tell, mask, inode_mark, + inode_test_mask, vfsmount_mark, vfsmount_test_mask, data, + data_is, cookie); + + if (!inode_test_mask && !vfsmount_test_mask) + return 0; + + return group->ops->handle_event(group, to_tell, inode_mark, + vfsmount_mark, mask, data, data_is, + file_name, cookie); +} + /* * This is the main call to fsnotify. The VFS calls into hook specific functions * in linux/fsnotify.h. Those functions then in turn call here. Here will call * out to all of the registered fsnotify_group. Those groups can then use the * notification event in whatever means they feel necessary. */ -void fsnotify(struct inode *to_tell, __u32 mask, void *data, int data_is, const char *file_name, u32 cookie) +int fsnotify(struct inode *to_tell, __u32 mask, void *data, int data_is, + const unsigned char *file_name, u32 cookie) { - struct fsnotify_group *group; - struct fsnotify_event *event = NULL; - int idx; + struct hlist_node *inode_node = NULL, *vfsmount_node = NULL; + struct fsnotify_mark *inode_mark = NULL, *vfsmount_mark = NULL; + struct fsnotify_group *inode_group, *vfsmount_group; + struct mount *mnt; + int idx, ret = 0; /* global tests shouldn't care about events on child only the specific event */ __u32 test_mask = (mask & ~FS_EVENT_ON_CHILD); - if (list_empty(&fsnotify_groups)) - return; + if (data_is == FSNOTIFY_EVENT_PATH) + mnt = real_mount(((struct path *)data)->mnt); + else + mnt = NULL; - if (!(test_mask & fsnotify_mask)) - return; - - if (!(test_mask & to_tell->i_fsnotify_mask)) - return; /* - * SRCU!! the groups list is very very much read only and the path is - * very hot. The VAST majority of events are not going to need to do - * anything other than walk the list so it's crazy to pre-allocate. + * if this is a modify event we may need to clear the ignored masks + * otherwise return if neither the inode nor the vfsmount care about + * this type of event. */ - idx = srcu_read_lock(&fsnotify_grp_srcu); - list_for_each_entry_rcu(group, &fsnotify_groups, group_list) { - if (test_mask & group->mask) { - if (!group->ops->should_send_event(group, to_tell, mask)) - continue; - if (!event) { - event = fsnotify_create_event(to_tell, mask, data, - data_is, file_name, cookie, - GFP_KERNEL); - /* shit, we OOM'd and now we can't tell, maybe - * someday someone else will want to do something - * here */ - if (!event) - break; - } - group->ops->handle_event(group, event); + if (!(mask & FS_MODIFY) && + !(test_mask & to_tell->i_fsnotify_mask) && + !(mnt && test_mask & mnt->mnt_fsnotify_mask)) + return 0; + + idx = srcu_read_lock(&fsnotify_mark_srcu); + + if ((mask & FS_MODIFY) || + (test_mask & to_tell->i_fsnotify_mask)) + inode_node = srcu_dereference(to_tell->i_fsnotify_marks.first, + &fsnotify_mark_srcu); + + if (mnt && ((mask & FS_MODIFY) || + (test_mask & mnt->mnt_fsnotify_mask))) { + vfsmount_node = srcu_dereference(mnt->mnt_fsnotify_marks.first, + &fsnotify_mark_srcu); + inode_node = srcu_dereference(to_tell->i_fsnotify_marks.first, + &fsnotify_mark_srcu); + } + + while (inode_node || vfsmount_node) { + inode_group = vfsmount_group = NULL; + + if (inode_node) { + inode_mark = hlist_entry(srcu_dereference(inode_node, &fsnotify_mark_srcu), + struct fsnotify_mark, i.i_list); + inode_group = inode_mark->group; } + + if (vfsmount_node) { + vfsmount_mark = hlist_entry(srcu_dereference(vfsmount_node, &fsnotify_mark_srcu), + struct fsnotify_mark, m.m_list); + vfsmount_group = vfsmount_mark->group; + } + + if (inode_group > vfsmount_group) { + /* handle inode */ + ret = send_to_group(to_tell, inode_mark, NULL, mask, + data, data_is, cookie, file_name); + /* we didn't use the vfsmount_mark */ + vfsmount_group = NULL; + } else if (vfsmount_group > inode_group) { + ret = send_to_group(to_tell, NULL, vfsmount_mark, mask, + data, data_is, cookie, file_name); + inode_group = NULL; + } else { + ret = send_to_group(to_tell, inode_mark, vfsmount_mark, + mask, data, data_is, cookie, + file_name); + } + + if (ret && (mask & ALL_FSNOTIFY_PERM_EVENTS)) + goto out; + + if (inode_group) + inode_node = srcu_dereference(inode_node->next, + &fsnotify_mark_srcu); + if (vfsmount_group) + vfsmount_node = srcu_dereference(vfsmount_node->next, + &fsnotify_mark_srcu); } - srcu_read_unlock(&fsnotify_grp_srcu, idx); - /* - * fsnotify_create_event() took a reference so the event can't be cleaned - * up while we are still trying to add it to lists, drop that one. - */ - if (event) - fsnotify_put_event(event); + ret = 0; +out: + srcu_read_unlock(&fsnotify_mark_srcu, idx); + + return ret; } EXPORT_SYMBOL_GPL(fsnotify); static __init int fsnotify_init(void) { - return init_srcu_struct(&fsnotify_grp_srcu); + int ret; + + BUG_ON(hweight32(ALL_FSNOTIFY_EVENTS) != 23); + + ret = init_srcu_struct(&fsnotify_mark_srcu); + if (ret) + panic("initializing fsnotify_mark_srcu"); + + return 0; } -subsys_initcall(fsnotify_init); +core_initcall(fsnotify_init); diff --git a/fs/notify/fsnotify.h b/fs/notify/fsnotify.h index 4dc240824b2..85e7d2b431d 100644 --- a/fs/notify/fsnotify.h +++ b/fs/notify/fsnotify.h @@ -6,21 +6,34 @@ #include <linux/srcu.h> #include <linux/types.h> -/* protects reads of fsnotify_groups */ -extern struct srcu_struct fsnotify_grp_srcu; -/* all groups which receive fsnotify events */ -extern struct list_head fsnotify_groups; -/* all bitwise OR of all event types (FS_*) for all fsnotify_groups */ -extern __u32 fsnotify_mask; - /* destroy all events sitting in this groups notification queue */ extern void fsnotify_flush_notify(struct fsnotify_group *group); +/* protects reads of inode and vfsmount marks list */ +extern struct srcu_struct fsnotify_mark_srcu; + +extern void fsnotify_set_inode_mark_mask_locked(struct fsnotify_mark *fsn_mark, + __u32 mask); +/* add a mark to an inode */ +extern int fsnotify_add_inode_mark(struct fsnotify_mark *mark, + struct fsnotify_group *group, struct inode *inode, + int allow_dups); +/* add a mark to a vfsmount */ +extern int fsnotify_add_vfsmount_mark(struct fsnotify_mark *mark, + struct fsnotify_group *group, struct vfsmount *mnt, + int allow_dups); + /* final kfree of a group */ extern void fsnotify_final_destroy_group(struct fsnotify_group *group); +/* vfsmount specific destruction of a mark */ +extern void fsnotify_destroy_vfsmount_mark(struct fsnotify_mark *mark); +/* inode specific destruction of a mark */ +extern void fsnotify_destroy_inode_mark(struct fsnotify_mark *mark); /* run the list of all marks associated with inode and flag them to be freed */ extern void fsnotify_clear_marks_by_inode(struct inode *inode); +/* run the list of all marks associated with vfsmount and flag them to be freed */ +extern void fsnotify_clear_marks_by_mount(struct vfsmount *mnt); /* * update the dentry->d_flags of all of inode's children to indicate if inode cares * about events that happen to its children. diff --git a/fs/notify/group.c b/fs/notify/group.c index 0e1677144bc..ad199598045 100644 --- a/fs/notify/group.c +++ b/fs/notify/group.c @@ -26,74 +26,13 @@ #include <linux/fsnotify_backend.h> #include "fsnotify.h" -#include <asm/atomic.h> - -/* protects writes to fsnotify_groups and fsnotify_mask */ -static DEFINE_MUTEX(fsnotify_grp_mutex); -/* protects reads while running the fsnotify_groups list */ -struct srcu_struct fsnotify_grp_srcu; -/* all groups registered to receive filesystem notifications */ -LIST_HEAD(fsnotify_groups); -/* bitwise OR of all events (FS_*) interesting to some group on this system */ -__u32 fsnotify_mask; - -/* - * When a new group registers or changes it's set of interesting events - * this function updates the fsnotify_mask to contain all interesting events - */ -void fsnotify_recalc_global_mask(void) -{ - struct fsnotify_group *group; - __u32 mask = 0; - int idx; - - idx = srcu_read_lock(&fsnotify_grp_srcu); - list_for_each_entry_rcu(group, &fsnotify_groups, group_list) - mask |= group->mask; - srcu_read_unlock(&fsnotify_grp_srcu, idx); - fsnotify_mask = mask; -} - -/* - * Update the group->mask by running all of the marks associated with this - * group and finding the bitwise | of all of the mark->mask. If we change - * the group->mask we need to update the global mask of events interesting - * to the system. - */ -void fsnotify_recalc_group_mask(struct fsnotify_group *group) -{ - __u32 mask = 0; - __u32 old_mask = group->mask; - struct fsnotify_mark_entry *entry; - - spin_lock(&group->mark_lock); - list_for_each_entry(entry, &group->mark_entries, g_list) - mask |= entry->mask; - spin_unlock(&group->mark_lock); - - group->mask = mask; - - if (old_mask != mask) - fsnotify_recalc_global_mask(); -} - -/* - * Take a reference to a group so things found under the fsnotify_grp_mutex - * can't get freed under us - */ -static void fsnotify_get_group(struct fsnotify_group *group) -{ - atomic_inc(&group->refcnt); -} +#include <linux/atomic.h> /* * Final freeing of a group */ void fsnotify_final_destroy_group(struct fsnotify_group *group) { - /* clear the notification queue of all events */ - fsnotify_flush_notify(group); - if (group->ops->free_group_priv) group->ops->free_group_priv(group); @@ -101,47 +40,37 @@ void fsnotify_final_destroy_group(struct fsnotify_group *group) } /* - * Trying to get rid of a group. We need to first get rid of any outstanding - * allocations and then free the group. Remember that fsnotify_clear_marks_by_group - * could miss marks that are being freed by inode and those marks could still - * hold a reference to this group (via group->num_marks) If we get into that - * situtation, the fsnotify_final_destroy_group will get called when that final - * mark is freed. + * Trying to get rid of a group. Remove all marks, flush all events and release + * the group reference. + * Note that another thread calling fsnotify_clear_marks_by_group() may still + * hold a ref to the group. */ -static void fsnotify_destroy_group(struct fsnotify_group *group) +void fsnotify_destroy_group(struct fsnotify_group *group) { - /* clear all inode mark entries for this group */ + /* clear all inode marks for this group */ fsnotify_clear_marks_by_group(group); - /* past the point of no return, matches the initial value of 1 */ - if (atomic_dec_and_test(&group->num_marks)) - fsnotify_final_destroy_group(group); -} + synchronize_srcu(&fsnotify_mark_srcu); -/* - * Remove this group from the global list of groups that will get events - * this can be done even if there are still references and things still using - * this group. This just stops the group from getting new events. - */ -static void __fsnotify_evict_group(struct fsnotify_group *group) -{ - BUG_ON(!mutex_is_locked(&fsnotify_grp_mutex)); + /* clear the notification queue of all events */ + fsnotify_flush_notify(group); + + /* + * Destroy overflow event (we cannot use fsnotify_destroy_event() as + * that deliberately ignores overflow events. + */ + if (group->overflow_event) + group->ops->free_event(group->overflow_event); - if (group->on_group_list) - list_del_rcu(&group->group_list); - group->on_group_list = 0; + fsnotify_put_group(group); } /* - * Called when a group is no longer interested in getting events. This can be - * used if a group is misbehaving or if for some reason a group should no longer - * get any filesystem events. + * Get reference to a group. */ -void fsnotify_evict_group(struct fsnotify_group *group) +void fsnotify_get_group(struct fsnotify_group *group) { - mutex_lock(&fsnotify_grp_mutex); - __fsnotify_evict_group(group); - mutex_unlock(&fsnotify_grp_mutex); + atomic_inc(&group->refcnt); } /* @@ -149,106 +78,41 @@ void fsnotify_evict_group(struct fsnotify_group *group) */ void fsnotify_put_group(struct fsnotify_group *group) { - if (!atomic_dec_and_mutex_lock(&group->refcnt, &fsnotify_grp_mutex)) - return; - - /* - * OK, now we know that there's no other users *and* we hold mutex, - * so no new references will appear - */ - __fsnotify_evict_group(group); - - /* - * now it's off the list, so the only thing we might care about is - * srcu access.... - */ - mutex_unlock(&fsnotify_grp_mutex); - synchronize_srcu(&fsnotify_grp_srcu); - - /* and now it is really dead. _Nothing_ could be seeing it */ - fsnotify_recalc_global_mask(); - fsnotify_destroy_group(group); -} - -/* - * Simply run the fsnotify_groups list and find a group which matches - * the given parameters. If a group is found we take a reference to that - * group. - */ -static struct fsnotify_group *fsnotify_find_group(unsigned int group_num, __u32 mask, - const struct fsnotify_ops *ops) -{ - struct fsnotify_group *group_iter; - struct fsnotify_group *group = NULL; - - BUG_ON(!mutex_is_locked(&fsnotify_grp_mutex)); - - list_for_each_entry_rcu(group_iter, &fsnotify_groups, group_list) { - if (group_iter->group_num == group_num) { - if ((group_iter->mask == mask) && - (group_iter->ops == ops)) { - fsnotify_get_group(group_iter); - group = group_iter; - } else - group = ERR_PTR(-EEXIST); - } - } - return group; + if (atomic_dec_and_test(&group->refcnt)) + fsnotify_final_destroy_group(group); } /* - * Either finds an existing group which matches the group_num, mask, and ops or - * creates a new group and adds it to the global group list. In either case we - * take a reference for the group returned. + * Create a new fsnotify_group and hold a reference for the group returned. */ -struct fsnotify_group *fsnotify_obtain_group(unsigned int group_num, __u32 mask, - const struct fsnotify_ops *ops) +struct fsnotify_group *fsnotify_alloc_group(const struct fsnotify_ops *ops) { - struct fsnotify_group *group, *tgroup; + struct fsnotify_group *group; - /* very low use, simpler locking if we just always alloc */ - group = kmalloc(sizeof(struct fsnotify_group), GFP_KERNEL); + group = kzalloc(sizeof(struct fsnotify_group), GFP_KERNEL); if (!group) return ERR_PTR(-ENOMEM); + /* set to 0 when there a no external references to this group */ atomic_set(&group->refcnt, 1); - - group->on_group_list = 0; - group->group_num = group_num; - group->mask = mask; + atomic_set(&group->num_marks, 0); mutex_init(&group->notification_mutex); INIT_LIST_HEAD(&group->notification_list); init_waitqueue_head(&group->notification_waitq); - group->q_len = 0; group->max_events = UINT_MAX; - spin_lock_init(&group->mark_lock); - atomic_set(&group->num_marks, 0); - INIT_LIST_HEAD(&group->mark_entries); + mutex_init(&group->mark_mutex); + INIT_LIST_HEAD(&group->marks_list); group->ops = ops; - mutex_lock(&fsnotify_grp_mutex); - tgroup = fsnotify_find_group(group_num, mask, ops); - if (tgroup) { - /* group already exists */ - mutex_unlock(&fsnotify_grp_mutex); - /* destroy the new one we made */ - fsnotify_put_group(group); - return tgroup; - } - - /* group not found, add a new one */ - list_add_rcu(&group->group_list, &fsnotify_groups); - group->on_group_list = 1; - /* being on the fsnotify_groups list holds one num_marks */ - atomic_inc(&group->num_marks); - - mutex_unlock(&fsnotify_grp_mutex); + return group; +} - if (mask) - fsnotify_recalc_global_mask(); +int fsnotify_fasync(int fd, struct file *file, int on) +{ + struct fsnotify_group *group = file->private_data; - return group; + return fasync_helper(fd, file, on, &group->fsn_fa) >= 0 ? 0 : -EIO; } diff --git a/fs/notify/inode_mark.c b/fs/notify/inode_mark.c index 3165d85aada..74825be65b7 100644 --- a/fs/notify/inode_mark.c +++ b/fs/notify/inode_mark.c @@ -16,110 +16,32 @@ * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */ -/* - * fsnotify inode mark locking/lifetime/and refcnting - * - * REFCNT: - * The mark->refcnt tells how many "things" in the kernel currently are - * referencing this object. The object typically will live inside the kernel - * with a refcnt of 2, one for each list it is on (i_list, g_list). Any task - * which can find this object holding the appropriete locks, can take a reference - * and the object itself is guarenteed to survive until the reference is dropped. - * - * LOCKING: - * There are 3 spinlocks involved with fsnotify inode marks and they MUST - * be taken in order as follows: - * - * entry->lock - * group->mark_lock - * inode->i_lock - * - * entry->lock protects 2 things, entry->group and entry->inode. You must hold - * that lock to dereference either of these things (they could be NULL even with - * the lock) - * - * group->mark_lock protects the mark_entries list anchored inside a given group - * and each entry is hooked via the g_list. It also sorta protects the - * free_g_list, which when used is anchored by a private list on the stack of the - * task which held the group->mark_lock. - * - * inode->i_lock protects the i_fsnotify_mark_entries list anchored inside a - * given inode and each entry is hooked via the i_list. (and sorta the - * free_i_list) - * - * - * LIFETIME: - * Inode marks survive between when they are added to an inode and when their - * refcnt==0. - * - * The inode mark can be cleared for a number of different reasons including: - * - The inode is unlinked for the last time. (fsnotify_inode_remove) - * - The inode is being evicted from cache. (fsnotify_inode_delete) - * - The fs the inode is on is unmounted. (fsnotify_inode_delete/fsnotify_unmount_inodes) - * - Something explicitly requests that it be removed. (fsnotify_destroy_mark_by_entry) - * - The fsnotify_group associated with the mark is going away and all such marks - * need to be cleaned up. (fsnotify_clear_marks_by_group) - * - * Worst case we are given an inode and need to clean up all the marks on that - * inode. We take i_lock and walk the i_fsnotify_mark_entries safely. For each - * mark on the list we take a reference (so the mark can't disappear under us). - * We remove that mark form the inode's list of marks and we add this mark to a - * private list anchored on the stack using i_free_list; At this point we no - * longer fear anything finding the mark using the inode's list of marks. - * - * We can safely and locklessly run the private list on the stack of everything - * we just unattached from the original inode. For each mark on the private list - * we grab the mark-> and can thus dereference mark->group and mark->inode. If - * we see the group and inode are not NULL we take those locks. Now holding all - * 3 locks we can completely remove the mark from other tasks finding it in the - * future. Remember, 10 things might already be referencing this mark, but they - * better be holding a ref. We drop our reference we took before we unhooked it - * from the inode. When the ref hits 0 we can free the mark. - * - * Very similarly for freeing by group, except we use free_g_list. - * - * This has the very interesting property of being able to run concurrently with - * any (or all) other directions. - */ - #include <linux/fs.h> #include <linux/init.h> #include <linux/kernel.h> #include <linux/module.h> #include <linux/mutex.h> -#include <linux/slab.h> #include <linux/spinlock.h> -#include <linux/writeback.h> /* for inode_lock */ -#include <asm/atomic.h> +#include <linux/atomic.h> #include <linux/fsnotify_backend.h> #include "fsnotify.h" -void fsnotify_get_mark(struct fsnotify_mark_entry *entry) -{ - atomic_inc(&entry->refcnt); -} - -void fsnotify_put_mark(struct fsnotify_mark_entry *entry) -{ - if (atomic_dec_and_test(&entry->refcnt)) - entry->free_mark(entry); -} +#include "../internal.h" /* * Recalculate the mask of events relevant to a given inode locked. */ static void fsnotify_recalc_inode_mask_locked(struct inode *inode) { - struct fsnotify_mark_entry *entry; - struct hlist_node *pos; + struct fsnotify_mark *mark; __u32 new_mask = 0; assert_spin_locked(&inode->i_lock); - hlist_for_each_entry(entry, pos, &inode->i_fsnotify_mark_entries, i_list) - new_mask |= entry->mask; + hlist_for_each_entry(mark, &inode->i_fsnotify_marks, i.i_list) + new_mask |= mark->mask; inode->i_fsnotify_mask = new_mask; } @@ -136,220 +58,184 @@ void fsnotify_recalc_inode_mask(struct inode *inode) __fsnotify_update_child_dentry_flags(inode); } -/* - * Any time a mark is getting freed we end up here. - * The caller had better be holding a reference to this mark so we don't actually - * do the final put under the entry->lock - */ -void fsnotify_destroy_mark_by_entry(struct fsnotify_mark_entry *entry) +void fsnotify_destroy_inode_mark(struct fsnotify_mark *mark) { - struct fsnotify_group *group; - struct inode *inode; - - spin_lock(&entry->lock); + struct inode *inode = mark->i.inode; - group = entry->group; - inode = entry->inode; - - BUG_ON(group && !inode); - BUG_ON(!group && inode); - - /* if !group something else already marked this to die */ - if (!group) { - spin_unlock(&entry->lock); - return; - } + BUG_ON(!mutex_is_locked(&mark->group->mark_mutex)); + assert_spin_locked(&mark->lock); - /* 1 from caller and 1 for being on i_list/g_list */ - BUG_ON(atomic_read(&entry->refcnt) < 2); - - spin_lock(&group->mark_lock); spin_lock(&inode->i_lock); - hlist_del_init(&entry->i_list); - entry->inode = NULL; - - list_del_init(&entry->g_list); - entry->group = NULL; - - fsnotify_put_mark(entry); /* for i_list and g_list */ + hlist_del_init_rcu(&mark->i.i_list); + mark->i.inode = NULL; /* - * this mark is now off the inode->i_fsnotify_mark_entries list and we + * this mark is now off the inode->i_fsnotify_marks list and we * hold the inode->i_lock, so this is the perfect time to update the * inode->i_fsnotify_mask */ fsnotify_recalc_inode_mask_locked(inode); spin_unlock(&inode->i_lock); - spin_unlock(&group->mark_lock); - spin_unlock(&entry->lock); - - /* - * Some groups like to know that marks are being freed. This is a - * callback to the group function to let it know that this entry - * is being freed. - */ - if (group->ops->freeing_mark) - group->ops->freeing_mark(entry, group); - - /* - * __fsnotify_update_child_dentry_flags(inode); - * - * I really want to call that, but we can't, we have no idea if the inode - * still exists the second we drop the entry->lock. - * - * The next time an event arrive to this inode from one of it's children - * __fsnotify_parent will see that the inode doesn't care about it's - * children and will update all of these flags then. So really this - * is just a lazy update (and could be a perf win...) - */ - - - iput(inode); - - /* - * it's possible that this group tried to destroy itself, but this - * this mark was simultaneously being freed by inode. If that's the - * case, we finish freeing the group here. - */ - if (unlikely(atomic_dec_and_test(&group->num_marks))) - fsnotify_final_destroy_group(group); } /* - * Given a group, destroy all of the marks associated with that group. + * Given an inode, destroy all of the marks associated with that inode. */ -void fsnotify_clear_marks_by_group(struct fsnotify_group *group) +void fsnotify_clear_marks_by_inode(struct inode *inode) { - struct fsnotify_mark_entry *lentry, *entry; + struct fsnotify_mark *mark, *lmark; + struct hlist_node *n; LIST_HEAD(free_list); - spin_lock(&group->mark_lock); - list_for_each_entry_safe(entry, lentry, &group->mark_entries, g_list) { - list_add(&entry->free_g_list, &free_list); - list_del_init(&entry->g_list); - fsnotify_get_mark(entry); + spin_lock(&inode->i_lock); + hlist_for_each_entry_safe(mark, n, &inode->i_fsnotify_marks, i.i_list) { + list_add(&mark->i.free_i_list, &free_list); + hlist_del_init_rcu(&mark->i.i_list); + fsnotify_get_mark(mark); } - spin_unlock(&group->mark_lock); + spin_unlock(&inode->i_lock); + + list_for_each_entry_safe(mark, lmark, &free_list, i.free_i_list) { + struct fsnotify_group *group; - list_for_each_entry_safe(entry, lentry, &free_list, free_g_list) { - fsnotify_destroy_mark_by_entry(entry); - fsnotify_put_mark(entry); + spin_lock(&mark->lock); + fsnotify_get_group(mark->group); + group = mark->group; + spin_unlock(&mark->lock); + + fsnotify_destroy_mark(mark, group); + fsnotify_put_mark(mark); + fsnotify_put_group(group); } } /* - * Given an inode, destroy all of the marks associated with that inode. + * Given a group clear all of the inode marks associated with that group. */ -void fsnotify_clear_marks_by_inode(struct inode *inode) +void fsnotify_clear_inode_marks_by_group(struct fsnotify_group *group) { - struct fsnotify_mark_entry *entry, *lentry; - struct hlist_node *pos, *n; - LIST_HEAD(free_list); - - spin_lock(&inode->i_lock); - hlist_for_each_entry_safe(entry, pos, n, &inode->i_fsnotify_mark_entries, i_list) { - list_add(&entry->free_i_list, &free_list); - hlist_del_init(&entry->i_list); - fsnotify_get_mark(entry); - } - spin_unlock(&inode->i_lock); - - list_for_each_entry_safe(entry, lentry, &free_list, free_i_list) { - fsnotify_destroy_mark_by_entry(entry); - fsnotify_put_mark(entry); - } + fsnotify_clear_marks_by_group_flags(group, FSNOTIFY_MARK_FLAG_INODE); } /* * given a group and inode, find the mark associated with that combination. * if found take a reference to that mark and return it, else return NULL */ -struct fsnotify_mark_entry *fsnotify_find_mark_entry(struct fsnotify_group *group, - struct inode *inode) +static struct fsnotify_mark *fsnotify_find_inode_mark_locked( + struct fsnotify_group *group, + struct inode *inode) { - struct fsnotify_mark_entry *entry; - struct hlist_node *pos; + struct fsnotify_mark *mark; assert_spin_locked(&inode->i_lock); - hlist_for_each_entry(entry, pos, &inode->i_fsnotify_mark_entries, i_list) { - if (entry->group == group) { - fsnotify_get_mark(entry); - return entry; + hlist_for_each_entry(mark, &inode->i_fsnotify_marks, i.i_list) { + if (mark->group == group) { + fsnotify_get_mark(mark); + return mark; } } return NULL; } /* - * Nothing fancy, just initialize lists and locks and counters. + * given a group and inode, find the mark associated with that combination. + * if found take a reference to that mark and return it, else return NULL */ -void fsnotify_init_mark(struct fsnotify_mark_entry *entry, - void (*free_mark)(struct fsnotify_mark_entry *entry)) +struct fsnotify_mark *fsnotify_find_inode_mark(struct fsnotify_group *group, + struct inode *inode) +{ + struct fsnotify_mark *mark; + spin_lock(&inode->i_lock); + mark = fsnotify_find_inode_mark_locked(group, inode); + spin_unlock(&inode->i_lock); + + return mark; +} + +/* + * If we are setting a mark mask on an inode mark we should pin the inode + * in memory. + */ +void fsnotify_set_inode_mark_mask_locked(struct fsnotify_mark *mark, + __u32 mask) { - spin_lock_init(&entry->lock); - atomic_set(&entry->refcnt, 1); - INIT_HLIST_NODE(&entry->i_list); - entry->group = NULL; - entry->mask = 0; - entry->inode = NULL; - entry->free_mark = free_mark; + struct inode *inode; + + assert_spin_locked(&mark->lock); + + if (mask && + mark->i.inode && + !(mark->flags & FSNOTIFY_MARK_FLAG_OBJECT_PINNED)) { + mark->flags |= FSNOTIFY_MARK_FLAG_OBJECT_PINNED; + inode = igrab(mark->i.inode); + /* + * we shouldn't be able to get here if the inode wasn't + * already safely held in memory. But bug in case it + * ever is wrong. + */ + BUG_ON(!inode); + } } /* - * Attach an initialized mark entry to a given group and inode. + * Attach an initialized mark to a given inode. * These marks may be used for the fsnotify backend to determine which - * event types should be delivered to which group and for which inodes. + * event types should be delivered to which group and for which inodes. These + * marks are ordered according to priority, highest number first, and then by + * the group's location in memory. */ -int fsnotify_add_mark(struct fsnotify_mark_entry *entry, - struct fsnotify_group *group, struct inode *inode) +int fsnotify_add_inode_mark(struct fsnotify_mark *mark, + struct fsnotify_group *group, struct inode *inode, + int allow_dups) { - struct fsnotify_mark_entry *lentry; + struct fsnotify_mark *lmark, *last = NULL; int ret = 0; - inode = igrab(inode); - if (unlikely(!inode)) - return -EINVAL; + mark->flags |= FSNOTIFY_MARK_FLAG_INODE; + + BUG_ON(!mutex_is_locked(&group->mark_mutex)); + assert_spin_locked(&mark->lock); - /* - * LOCKING ORDER!!!! - * entry->lock - * group->mark_lock - * inode->i_lock - */ - spin_lock(&entry->lock); - spin_lock(&group->mark_lock); spin_lock(&inode->i_lock); - lentry = fsnotify_find_mark_entry(group, inode); - if (!lentry) { - entry->group = group; - entry->inode = inode; + mark->i.inode = inode; + + /* is mark the first mark? */ + if (hlist_empty(&inode->i_fsnotify_marks)) { + hlist_add_head_rcu(&mark->i.i_list, &inode->i_fsnotify_marks); + goto out; + } + + /* should mark be in the middle of the current list? */ + hlist_for_each_entry(lmark, &inode->i_fsnotify_marks, i.i_list) { + last = lmark; - hlist_add_head(&entry->i_list, &inode->i_fsnotify_mark_entries); - list_add(&entry->g_list, &group->mark_entries); + if ((lmark->group == group) && !allow_dups) { + ret = -EEXIST; + goto out; + } - fsnotify_get_mark(entry); /* for i_list and g_list */ + if (mark->group->priority < lmark->group->priority) + continue; - atomic_inc(&group->num_marks); + if ((mark->group->priority == lmark->group->priority) && + (mark->group < lmark->group)) + continue; - fsnotify_recalc_inode_mask_locked(inode); + hlist_add_before_rcu(&mark->i.i_list, &lmark->i.i_list); + goto out; } + BUG_ON(last == NULL); + /* mark should be the last entry. last is the current last entry */ + hlist_add_after_rcu(&last->i.i_list, &mark->i.i_list); +out: + fsnotify_recalc_inode_mask_locked(inode); spin_unlock(&inode->i_lock); - spin_unlock(&group->mark_lock); - spin_unlock(&entry->lock); - - if (lentry) { - ret = -EEXIST; - iput(inode); - fsnotify_put_mark(lentry); - } else { - __fsnotify_update_child_dentry_flags(inode); - } return ret; } @@ -358,24 +244,27 @@ int fsnotify_add_mark(struct fsnotify_mark_entry *entry, * fsnotify_unmount_inodes - an sb is unmounting. handle any watched inodes. * @list: list of inodes being unmounted (sb->s_inodes) * - * Called with inode_lock held, protecting the unmounting super block's list - * of inodes, and with iprune_mutex held, keeping shrink_icache_memory() at bay. - * We temporarily drop inode_lock, however, and CAN block. + * Called during unmount with no locks held, so needs to be safe against + * concurrent modifiers. We temporarily drop inode_sb_list_lock and CAN block. */ void fsnotify_unmount_inodes(struct list_head *list) { struct inode *inode, *next_i, *need_iput = NULL; + spin_lock(&inode_sb_list_lock); list_for_each_entry_safe(inode, next_i, list, i_sb_list) { struct inode *need_iput_tmp; /* - * We cannot __iget() an inode in state I_CLEAR, I_FREEING, + * We cannot __iget() an inode in state I_FREEING, * I_WILL_FREE, or I_NEW which is fine because by that point * the inode cannot have any associated watches. */ - if (inode->i_state & (I_CLEAR|I_FREEING|I_WILL_FREE|I_NEW)) + spin_lock(&inode->i_lock); + if (inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW)) { + spin_unlock(&inode->i_lock); continue; + } /* * If i_count is zero, the inode cannot have any watches and @@ -383,8 +272,10 @@ void fsnotify_unmount_inodes(struct list_head *list) * evict all inodes with zero i_count from icache which is * unnecessarily violent and may in fact be illegal to do. */ - if (!atomic_read(&inode->i_count)) + if (!atomic_read(&inode->i_count)) { + spin_unlock(&inode->i_lock); continue; + } need_iput_tmp = need_iput; need_iput = NULL; @@ -394,22 +285,25 @@ void fsnotify_unmount_inodes(struct list_head *list) __iget(inode); else need_iput_tmp = NULL; + spin_unlock(&inode->i_lock); /* In case the dropping of a reference would nuke next_i. */ if ((&next_i->i_sb_list != list) && - atomic_read(&next_i->i_count) && - !(next_i->i_state & (I_CLEAR | I_FREEING | I_WILL_FREE))) { - __iget(next_i); - need_iput = next_i; + atomic_read(&next_i->i_count)) { + spin_lock(&next_i->i_lock); + if (!(next_i->i_state & (I_FREEING | I_WILL_FREE))) { + __iget(next_i); + need_iput = next_i; + } + spin_unlock(&next_i->i_lock); } /* - * We can safely drop inode_lock here because we hold + * We can safely drop inode_sb_list_lock here because we hold * references on both inode and next_i. Also no new inodes - * will be added since the umount has begun. Finally, - * iprune_mutex keeps shrink_icache_memory() away. + * will be added since the umount has begun. */ - spin_unlock(&inode_lock); + spin_unlock(&inode_sb_list_lock); if (need_iput_tmp) iput(need_iput_tmp); @@ -421,6 +315,7 @@ void fsnotify_unmount_inodes(struct list_head *list) iput(inode); - spin_lock(&inode_lock); + spin_lock(&inode_sb_list_lock); } + spin_unlock(&inode_sb_list_lock); } diff --git a/fs/notify/inotify/Kconfig b/fs/notify/inotify/Kconfig index 3e56dbffe72..b981fc0c837 100644 --- a/fs/notify/inotify/Kconfig +++ b/fs/notify/inotify/Kconfig @@ -1,20 +1,6 @@ -config INOTIFY - bool "Inotify file change notification support" - default n - ---help--- - Say Y here to enable legacy in kernel inotify support. Inotify is a - file change notification system. It is a replacement for dnotify. - This option only provides the legacy inotify in kernel API. There - are no in tree kernel users of this interface since it is deprecated. - You only need this if you are loading an out of tree kernel module - that uses inotify. - - For more information, see <file:Documentation/filesystems/inotify.txt> - - If unsure, say N. - config INOTIFY_USER bool "Inotify support for userspace" + select ANON_INODES select FSNOTIFY default y ---help--- diff --git a/fs/notify/inotify/Makefile b/fs/notify/inotify/Makefile index 94382817136..a380dabe09d 100644 --- a/fs/notify/inotify/Makefile +++ b/fs/notify/inotify/Makefile @@ -1,2 +1 @@ -obj-$(CONFIG_INOTIFY) += inotify.o obj-$(CONFIG_INOTIFY_USER) += inotify_fsnotify.o inotify_user.o diff --git a/fs/notify/inotify/inotify.c b/fs/notify/inotify/inotify.c deleted file mode 100644 index 40b1cf914cc..00000000000 --- a/fs/notify/inotify/inotify.c +++ /dev/null @@ -1,933 +0,0 @@ -/* - * fs/inotify.c - inode-based file event notifications - * - * Authors: - * John McCutchan <ttb@tentacle.dhs.org> - * Robert Love <rml@novell.com> - * - * Kernel API added by: Amy Griffis <amy.griffis@hp.com> - * - * Copyright (C) 2005 John McCutchan - * Copyright 2006 Hewlett-Packard Development Company, L.P. - * - * This program is free software; you can redistribute it and/or modify it - * under the terms of the GNU General Public License as published by the - * Free Software Foundation; either version 2, or (at your option) any - * later version. - * - * This program is distributed in the hope that it will be useful, but - * WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU - * General Public License for more details. - */ - -#include <linux/module.h> -#include <linux/kernel.h> -#include <linux/spinlock.h> -#include <linux/idr.h> -#include <linux/slab.h> -#include <linux/fs.h> -#include <linux/sched.h> -#include <linux/init.h> -#include <linux/list.h> -#include <linux/writeback.h> -#include <linux/inotify.h> -#include <linux/fsnotify_backend.h> - -static atomic_t inotify_cookie; - -/* - * Lock ordering: - * - * dentry->d_lock (used to keep d_move() away from dentry->d_parent) - * iprune_mutex (synchronize shrink_icache_memory()) - * inode_lock (protects the super_block->s_inodes list) - * inode->inotify_mutex (protects inode->inotify_watches and watches->i_list) - * inotify_handle->mutex (protects inotify_handle and watches->h_list) - * - * The inode->inotify_mutex and inotify_handle->mutex and held during execution - * of a caller's event handler. Thus, the caller must not hold any locks - * taken in their event handler while calling any of the published inotify - * interfaces. - */ - -/* - * Lifetimes of the three main data structures--inotify_handle, inode, and - * inotify_watch--are managed by reference count. - * - * inotify_handle: Lifetime is from inotify_init() to inotify_destroy(). - * Additional references can bump the count via get_inotify_handle() and drop - * the count via put_inotify_handle(). - * - * inotify_watch: for inotify's purposes, lifetime is from inotify_add_watch() - * to remove_watch_no_event(). Additional references can bump the count via - * get_inotify_watch() and drop the count via put_inotify_watch(). The caller - * is reponsible for the final put after receiving IN_IGNORED, or when using - * IN_ONESHOT after receiving the first event. Inotify does the final put if - * inotify_destroy() is called. - * - * inode: Pinned so long as the inode is associated with a watch, from - * inotify_add_watch() to the final put_inotify_watch(). - */ - -/* - * struct inotify_handle - represents an inotify instance - * - * This structure is protected by the mutex 'mutex'. - */ -struct inotify_handle { - struct idr idr; /* idr mapping wd -> watch */ - struct mutex mutex; /* protects this bad boy */ - struct list_head watches; /* list of watches */ - atomic_t count; /* reference count */ - u32 last_wd; /* the last wd allocated */ - const struct inotify_operations *in_ops; /* inotify caller operations */ -}; - -static inline void get_inotify_handle(struct inotify_handle *ih) -{ - atomic_inc(&ih->count); -} - -static inline void put_inotify_handle(struct inotify_handle *ih) -{ - if (atomic_dec_and_test(&ih->count)) { - idr_destroy(&ih->idr); - kfree(ih); - } -} - -/** - * get_inotify_watch - grab a reference to an inotify_watch - * @watch: watch to grab - */ -void get_inotify_watch(struct inotify_watch *watch) -{ - atomic_inc(&watch->count); -} -EXPORT_SYMBOL_GPL(get_inotify_watch); - -int pin_inotify_watch(struct inotify_watch *watch) -{ - struct super_block *sb = watch->inode->i_sb; - spin_lock(&sb_lock); - if (sb->s_count >= S_BIAS) { - atomic_inc(&sb->s_active); - spin_unlock(&sb_lock); - atomic_inc(&watch->count); - return 1; - } - spin_unlock(&sb_lock); - return 0; -} - -/** - * put_inotify_watch - decrements the ref count on a given watch. cleans up - * watch references if the count reaches zero. inotify_watch is freed by - * inotify callers via the destroy_watch() op. - * @watch: watch to release - */ -void put_inotify_watch(struct inotify_watch *watch) -{ - if (atomic_dec_and_test(&watch->count)) { - struct inotify_handle *ih = watch->ih; - - iput(watch->inode); - ih->in_ops->destroy_watch(watch); - put_inotify_handle(ih); - } -} -EXPORT_SYMBOL_GPL(put_inotify_watch); - -void unpin_inotify_watch(struct inotify_watch *watch) -{ - struct super_block *sb = watch->inode->i_sb; - put_inotify_watch(watch); - deactivate_super(sb); -} - -/* - * inotify_handle_get_wd - returns the next WD for use by the given handle - * - * Callers must hold ih->mutex. This function can sleep. - */ -static int inotify_handle_get_wd(struct inotify_handle *ih, - struct inotify_watch *watch) -{ - int ret; - - do { - if (unlikely(!idr_pre_get(&ih->idr, GFP_NOFS))) - return -ENOSPC; - ret = idr_get_new_above(&ih->idr, watch, ih->last_wd+1, &watch->wd); - } while (ret == -EAGAIN); - - if (likely(!ret)) - ih->last_wd = watch->wd; - - return ret; -} - -/* - * inotify_inode_watched - returns nonzero if there are watches on this inode - * and zero otherwise. We call this lockless, we do not care if we race. - */ -static inline int inotify_inode_watched(struct inode *inode) -{ - return !list_empty(&inode->inotify_watches); -} - -/* - * Get child dentry flag into synch with parent inode. - * Flag should always be clear for negative dentrys. - */ -static void set_dentry_child_flags(struct inode *inode, int watched) -{ - struct dentry *alias; - - spin_lock(&dcache_lock); - list_for_each_entry(alias, &inode->i_dentry, d_alias) { - struct dentry *child; - - list_for_each_entry(child, &alias->d_subdirs, d_u.d_child) { - if (!child->d_inode) - continue; - - spin_lock(&child->d_lock); - if (watched) - child->d_flags |= DCACHE_INOTIFY_PARENT_WATCHED; - else - child->d_flags &=~DCACHE_INOTIFY_PARENT_WATCHED; - spin_unlock(&child->d_lock); - } - } - spin_unlock(&dcache_lock); -} - -/* - * inotify_find_handle - find the watch associated with the given inode and - * handle - * - * Callers must hold inode->inotify_mutex. - */ -static struct inotify_watch *inode_find_handle(struct inode *inode, - struct inotify_handle *ih) -{ - struct inotify_watch *watch; - - list_for_each_entry(watch, &inode->inotify_watches, i_list) { - if (watch->ih == ih) - return watch; - } - - return NULL; -} - -/* - * remove_watch_no_event - remove watch without the IN_IGNORED event. - * - * Callers must hold both inode->inotify_mutex and ih->mutex. - */ -static void remove_watch_no_event(struct inotify_watch *watch, - struct inotify_handle *ih) -{ - list_del(&watch->i_list); - list_del(&watch->h_list); - - if (!inotify_inode_watched(watch->inode)) - set_dentry_child_flags(watch->inode, 0); - - idr_remove(&ih->idr, watch->wd); -} - -/** - * inotify_remove_watch_locked - Remove a watch from both the handle and the - * inode. Sends the IN_IGNORED event signifying that the inode is no longer - * watched. May be invoked from a caller's event handler. - * @ih: inotify handle associated with watch - * @watch: watch to remove - * - * Callers must hold both inode->inotify_mutex and ih->mutex. - */ -void inotify_remove_watch_locked(struct inotify_handle *ih, - struct inotify_watch *watch) -{ - remove_watch_no_event(watch, ih); - ih->in_ops->handle_event(watch, watch->wd, IN_IGNORED, 0, NULL, NULL); -} -EXPORT_SYMBOL_GPL(inotify_remove_watch_locked); - -/* Kernel API for producing events */ - -/* - * inotify_d_instantiate - instantiate dcache entry for inode - */ -void inotify_d_instantiate(struct dentry *entry, struct inode *inode) -{ - struct dentry *parent; - - if (!inode) - return; - - spin_lock(&entry->d_lock); - parent = entry->d_parent; - if (parent->d_inode && inotify_inode_watched(parent->d_inode)) - entry->d_flags |= DCACHE_INOTIFY_PARENT_WATCHED; - spin_unlock(&entry->d_lock); -} - -/* - * inotify_d_move - dcache entry has been moved - */ -void inotify_d_move(struct dentry *entry) -{ - struct dentry *parent; - - parent = entry->d_parent; - if (inotify_inode_watched(parent->d_inode)) - entry->d_flags |= DCACHE_INOTIFY_PARENT_WATCHED; - else - entry->d_flags &= ~DCACHE_INOTIFY_PARENT_WATCHED; -} - -/** - * inotify_inode_queue_event - queue an event to all watches on this inode - * @inode: inode event is originating from - * @mask: event mask describing this event - * @cookie: cookie for synchronization, or zero - * @name: filename, if any - * @n_inode: inode associated with name - */ -void inotify_inode_queue_event(struct inode *inode, u32 mask, u32 cookie, - const char *name, struct inode *n_inode) -{ - struct inotify_watch *watch, *next; - - if (!inotify_inode_watched(inode)) - return; - - mutex_lock(&inode->inotify_mutex); - list_for_each_entry_safe(watch, next, &inode->inotify_watches, i_list) { - u32 watch_mask = watch->mask; - if (watch_mask & mask) { - struct inotify_handle *ih= watch->ih; - mutex_lock(&ih->mutex); - if (watch_mask & IN_ONESHOT) - remove_watch_no_event(watch, ih); - ih->in_ops->handle_event(watch, watch->wd, mask, cookie, - name, n_inode); - mutex_unlock(&ih->mutex); - } - } - mutex_unlock(&inode->inotify_mutex); -} -EXPORT_SYMBOL_GPL(inotify_inode_queue_event); - -/** - * inotify_dentry_parent_queue_event - queue an event to a dentry's parent - * @dentry: the dentry in question, we queue against this dentry's parent - * @mask: event mask describing this event - * @cookie: cookie for synchronization, or zero - * @name: filename, if any - */ -void inotify_dentry_parent_queue_event(struct dentry *dentry, u32 mask, - u32 cookie, const char *name) -{ - struct dentry *parent; - struct inode *inode; - - if (!(dentry->d_flags & DCACHE_INOTIFY_PARENT_WATCHED)) - return; - - spin_lock(&dentry->d_lock); - parent = dentry->d_parent; - inode = parent->d_inode; - - if (inotify_inode_watched(inode)) { - dget(parent); - spin_unlock(&dentry->d_lock); - inotify_inode_queue_event(inode, mask, cookie, name, - dentry->d_inode); - dput(parent); - } else - spin_unlock(&dentry->d_lock); -} -EXPORT_SYMBOL_GPL(inotify_dentry_parent_queue_event); - -/** - * inotify_get_cookie - return a unique cookie for use in synchronizing events. - */ -u32 inotify_get_cookie(void) -{ - return atomic_inc_return(&inotify_cookie); -} -EXPORT_SYMBOL_GPL(inotify_get_cookie); - -/** - * inotify_unmount_inodes - an sb is unmounting. handle any watched inodes. - * @list: list of inodes being unmounted (sb->s_inodes) - * - * Called with inode_lock held, protecting the unmounting super block's list - * of inodes, and with iprune_mutex held, keeping shrink_icache_memory() at bay. - * We temporarily drop inode_lock, however, and CAN block. - */ -void inotify_unmount_inodes(struct list_head *list) -{ - struct inode *inode, *next_i, *need_iput = NULL; - - list_for_each_entry_safe(inode, next_i, list, i_sb_list) { - struct inotify_watch *watch, *next_w; - struct inode *need_iput_tmp; - struct list_head *watches; - - /* - * We cannot __iget() an inode in state I_CLEAR, I_FREEING, - * I_WILL_FREE, or I_NEW which is fine because by that point - * the inode cannot have any associated watches. - */ - if (inode->i_state & (I_CLEAR|I_FREEING|I_WILL_FREE|I_NEW)) - continue; - - /* - * If i_count is zero, the inode cannot have any watches and - * doing an __iget/iput with MS_ACTIVE clear would actually - * evict all inodes with zero i_count from icache which is - * unnecessarily violent and may in fact be illegal to do. - */ - if (!atomic_read(&inode->i_count)) - continue; - - need_iput_tmp = need_iput; - need_iput = NULL; - /* In case inotify_remove_watch_locked() drops a reference. */ - if (inode != need_iput_tmp) - __iget(inode); - else - need_iput_tmp = NULL; - /* In case the dropping of a reference would nuke next_i. */ - if ((&next_i->i_sb_list != list) && - atomic_read(&next_i->i_count) && - !(next_i->i_state & (I_CLEAR | I_FREEING | - I_WILL_FREE))) { - __iget(next_i); - need_iput = next_i; - } - - /* - * We can safely drop inode_lock here because we hold - * references on both inode and next_i. Also no new inodes - * will be added since the umount has begun. Finally, - * iprune_mutex keeps shrink_icache_memory() away. - */ - spin_unlock(&inode_lock); - - if (need_iput_tmp) - iput(need_iput_tmp); - - /* for each watch, send IN_UNMOUNT and then remove it */ - mutex_lock(&inode->inotify_mutex); - watches = &inode->inotify_watches; - list_for_each_entry_safe(watch, next_w, watches, i_list) { - struct inotify_handle *ih= watch->ih; - get_inotify_watch(watch); - mutex_lock(&ih->mutex); - ih->in_ops->handle_event(watch, watch->wd, IN_UNMOUNT, 0, - NULL, NULL); - inotify_remove_watch_locked(ih, watch); - mutex_unlock(&ih->mutex); - put_inotify_watch(watch); - } - mutex_unlock(&inode->inotify_mutex); - iput(inode); - - spin_lock(&inode_lock); - } -} -EXPORT_SYMBOL_GPL(inotify_unmount_inodes); - -/** - * inotify_inode_is_dead - an inode has been deleted, cleanup any watches - * @inode: inode that is about to be removed - */ -void inotify_inode_is_dead(struct inode *inode) -{ - struct inotify_watch *watch, *next; - - mutex_lock(&inode->inotify_mutex); - list_for_each_entry_safe(watch, next, &inode->inotify_watches, i_list) { - struct inotify_handle *ih = watch->ih; - mutex_lock(&ih->mutex); - inotify_remove_watch_locked(ih, watch); - mutex_unlock(&ih->mutex); - } - mutex_unlock(&inode->inotify_mutex); -} -EXPORT_SYMBOL_GPL(inotify_inode_is_dead); - -/* Kernel Consumer API */ - -/** - * inotify_init - allocate and initialize an inotify instance - * @ops: caller's inotify operations - */ -struct inotify_handle *inotify_init(const struct inotify_operations *ops) -{ - struct inotify_handle *ih; - - ih = kmalloc(sizeof(struct inotify_handle), GFP_KERNEL); - if (unlikely(!ih)) - return ERR_PTR(-ENOMEM); - - idr_init(&ih->idr); - INIT_LIST_HEAD(&ih->watches); - mutex_init(&ih->mutex); - ih->last_wd = 0; - ih->in_ops = ops; - atomic_set(&ih->count, 0); - get_inotify_handle(ih); - - return ih; -} -EXPORT_SYMBOL_GPL(inotify_init); - -/** - * inotify_init_watch - initialize an inotify watch - * @watch: watch to initialize - */ -void inotify_init_watch(struct inotify_watch *watch) -{ - INIT_LIST_HEAD(&watch->h_list); - INIT_LIST_HEAD(&watch->i_list); - atomic_set(&watch->count, 0); - get_inotify_watch(watch); /* initial get */ -} -EXPORT_SYMBOL_GPL(inotify_init_watch); - -/* - * Watch removals suck violently. To kick the watch out we need (in this - * order) inode->inotify_mutex and ih->mutex. That's fine if we have - * a hold on inode; however, for all other cases we need to make damn sure - * we don't race with umount. We can *NOT* just grab a reference to a - * watch - inotify_unmount_inodes() will happily sail past it and we'll end - * with reference to inode potentially outliving its superblock. Ideally - * we just want to grab an active reference to superblock if we can; that - * will make sure we won't go into inotify_umount_inodes() until we are - * done. Cleanup is just deactivate_super(). However, that leaves a messy - * case - what if we *are* racing with umount() and active references to - * superblock can't be acquired anymore? We can bump ->s_count, grab - * ->s_umount, which will almost certainly wait until the superblock is shut - * down and the watch in question is pining for fjords. That's fine, but - * there is a problem - we might have hit the window between ->s_active - * getting to 0 / ->s_count - below S_BIAS (i.e. the moment when superblock - * is past the point of no return and is heading for shutdown) and the - * moment when deactivate_super() acquires ->s_umount. We could just do - * drop_super() yield() and retry, but that's rather antisocial and this - * stuff is luser-triggerable. OTOH, having grabbed ->s_umount and having - * found that we'd got there first (i.e. that ->s_root is non-NULL) we know - * that we won't race with inotify_umount_inodes(). So we could grab a - * reference to watch and do the rest as above, just with drop_super() instead - * of deactivate_super(), right? Wrong. We had to drop ih->mutex before we - * could grab ->s_umount. So the watch could've been gone already. - * - * That still can be dealt with - we need to save watch->wd, do idr_find() - * and compare its result with our pointer. If they match, we either have - * the damn thing still alive or we'd lost not one but two races at once, - * the watch had been killed and a new one got created with the same ->wd - * at the same address. That couldn't have happened in inotify_destroy(), - * but inotify_rm_wd() could run into that. Still, "new one got created" - * is not a problem - we have every right to kill it or leave it alone, - * whatever's more convenient. - * - * So we can use idr_find(...) == watch && watch->inode->i_sb == sb as - * "grab it and kill it" check. If it's been our original watch, we are - * fine, if it's a newcomer - nevermind, just pretend that we'd won the - * race and kill the fscker anyway; we are safe since we know that its - * superblock won't be going away. - * - * And yes, this is far beyond mere "not very pretty"; so's the entire - * concept of inotify to start with. - */ - -/** - * pin_to_kill - pin the watch down for removal - * @ih: inotify handle - * @watch: watch to kill - * - * Called with ih->mutex held, drops it. Possible return values: - * 0 - nothing to do, it has died - * 1 - remove it, drop the reference and deactivate_super() - * 2 - remove it, drop the reference and drop_super(); we tried hard to avoid - * that variant, since it involved a lot of PITA, but that's the best that - * could've been done. - */ -static int pin_to_kill(struct inotify_handle *ih, struct inotify_watch *watch) -{ - struct super_block *sb = watch->inode->i_sb; - s32 wd = watch->wd; - - spin_lock(&sb_lock); - if (sb->s_count >= S_BIAS) { - atomic_inc(&sb->s_active); - spin_unlock(&sb_lock); - get_inotify_watch(watch); - mutex_unlock(&ih->mutex); - return 1; /* the best outcome */ - } - sb->s_count++; - spin_unlock(&sb_lock); - mutex_unlock(&ih->mutex); /* can't grab ->s_umount under it */ - down_read(&sb->s_umount); - if (likely(!sb->s_root)) { - /* fs is already shut down; the watch is dead */ - drop_super(sb); - return 0; - } - /* raced with the final deactivate_super() */ - mutex_lock(&ih->mutex); - if (idr_find(&ih->idr, wd) != watch || watch->inode->i_sb != sb) { - /* the watch is dead */ - mutex_unlock(&ih->mutex); - drop_super(sb); - return 0; - } - /* still alive or freed and reused with the same sb and wd; kill */ - get_inotify_watch(watch); - mutex_unlock(&ih->mutex); - return 2; -} - -static void unpin_and_kill(struct inotify_watch *watch, int how) -{ - struct super_block *sb = watch->inode->i_sb; - put_inotify_watch(watch); - switch (how) { - case 1: - deactivate_super(sb); - break; - case 2: - drop_super(sb); - } -} - -/** - * inotify_destroy - clean up and destroy an inotify instance - * @ih: inotify handle - */ -void inotify_destroy(struct inotify_handle *ih) -{ - /* - * Destroy all of the watches for this handle. Unfortunately, not very - * pretty. We cannot do a simple iteration over the list, because we - * do not know the inode until we iterate to the watch. But we need to - * hold inode->inotify_mutex before ih->mutex. The following works. - * - * AV: it had to become even uglier to start working ;-/ - */ - while (1) { - struct inotify_watch *watch; - struct list_head *watches; - struct super_block *sb; - struct inode *inode; - int how; - - mutex_lock(&ih->mutex); - watches = &ih->watches; - if (list_empty(watches)) { - mutex_unlock(&ih->mutex); - break; - } - watch = list_first_entry(watches, struct inotify_watch, h_list); - sb = watch->inode->i_sb; - how = pin_to_kill(ih, watch); - if (!how) - continue; - - inode = watch->inode; - mutex_lock(&inode->inotify_mutex); - mutex_lock(&ih->mutex); - - /* make sure we didn't race with another list removal */ - if (likely(idr_find(&ih->idr, watch->wd))) { - remove_watch_no_event(watch, ih); - put_inotify_watch(watch); - } - - mutex_unlock(&ih->mutex); - mutex_unlock(&inode->inotify_mutex); - unpin_and_kill(watch, how); - } - - /* free this handle: the put matching the get in inotify_init() */ - put_inotify_handle(ih); -} -EXPORT_SYMBOL_GPL(inotify_destroy); - -/** - * inotify_find_watch - find an existing watch for an (ih,inode) pair - * @ih: inotify handle - * @inode: inode to watch - * @watchp: pointer to existing inotify_watch - * - * Caller must pin given inode (via nameidata). - */ -s32 inotify_find_watch(struct inotify_handle *ih, struct inode *inode, - struct inotify_watch **watchp) -{ - struct inotify_watch *old; - int ret = -ENOENT; - - mutex_lock(&inode->inotify_mutex); - mutex_lock(&ih->mutex); - - old = inode_find_handle(inode, ih); - if (unlikely(old)) { - get_inotify_watch(old); /* caller must put watch */ - *watchp = old; - ret = old->wd; - } - - mutex_unlock(&ih->mutex); - mutex_unlock(&inode->inotify_mutex); - - return ret; -} -EXPORT_SYMBOL_GPL(inotify_find_watch); - -/** - * inotify_find_update_watch - find and update the mask of an existing watch - * @ih: inotify handle - * @inode: inode's watch to update - * @mask: mask of events to watch - * - * Caller must pin given inode (via nameidata). - */ -s32 inotify_find_update_watch(struct inotify_handle *ih, struct inode *inode, - u32 mask) -{ - struct inotify_watch *old; - int mask_add = 0; - int ret; - - if (mask & IN_MASK_ADD) - mask_add = 1; - - /* don't allow invalid bits: we don't want flags set */ - mask &= IN_ALL_EVENTS | IN_ONESHOT; - if (unlikely(!mask)) - return -EINVAL; - - mutex_lock(&inode->inotify_mutex); - mutex_lock(&ih->mutex); - - /* - * Handle the case of re-adding a watch on an (inode,ih) pair that we - * are already watching. We just update the mask and return its wd. - */ - old = inode_find_handle(inode, ih); - if (unlikely(!old)) { - ret = -ENOENT; - goto out; - } - - if (mask_add) - old->mask |= mask; - else - old->mask = mask; - ret = old->wd; -out: - mutex_unlock(&ih->mutex); - mutex_unlock(&inode->inotify_mutex); - return ret; -} -EXPORT_SYMBOL_GPL(inotify_find_update_watch); - -/** - * inotify_add_watch - add a watch to an inotify instance - * @ih: inotify handle - * @watch: caller allocated watch structure - * @inode: inode to watch - * @mask: mask of events to watch - * - * Caller must pin given inode (via nameidata). - * Caller must ensure it only calls inotify_add_watch() once per watch. - * Calls inotify_handle_get_wd() so may sleep. - */ -s32 inotify_add_watch(struct inotify_handle *ih, struct inotify_watch *watch, - struct inode *inode, u32 mask) -{ - int ret = 0; - int newly_watched; - - /* don't allow invalid bits: we don't want flags set */ - mask &= IN_ALL_EVENTS | IN_ONESHOT; - if (unlikely(!mask)) - return -EINVAL; - watch->mask = mask; - - mutex_lock(&inode->inotify_mutex); - mutex_lock(&ih->mutex); - - /* Initialize a new watch */ - ret = inotify_handle_get_wd(ih, watch); - if (unlikely(ret)) - goto out; - ret = watch->wd; - - /* save a reference to handle and bump the count to make it official */ - get_inotify_handle(ih); - watch->ih = ih; - - /* - * Save a reference to the inode and bump the ref count to make it - * official. We hold a reference to nameidata, which makes this safe. - */ - watch->inode = igrab(inode); - - /* Add the watch to the handle's and the inode's list */ - newly_watched = !inotify_inode_watched(inode); - list_add(&watch->h_list, &ih->watches); - list_add(&watch->i_list, &inode->inotify_watches); - /* - * Set child flags _after_ adding the watch, so there is no race - * windows where newly instantiated children could miss their parent's - * watched flag. - */ - if (newly_watched) - set_dentry_child_flags(inode, 1); - -out: - mutex_unlock(&ih->mutex); - mutex_unlock(&inode->inotify_mutex); - return ret; -} -EXPORT_SYMBOL_GPL(inotify_add_watch); - -/** - * inotify_clone_watch - put the watch next to existing one - * @old: already installed watch - * @new: new watch - * - * Caller must hold the inotify_mutex of inode we are dealing with; - * it is expected to remove the old watch before unlocking the inode. - */ -s32 inotify_clone_watch(struct inotify_watch *old, struct inotify_watch *new) -{ - struct inotify_handle *ih = old->ih; - int ret = 0; - - new->mask = old->mask; - new->ih = ih; - - mutex_lock(&ih->mutex); - - /* Initialize a new watch */ - ret = inotify_handle_get_wd(ih, new); - if (unlikely(ret)) - goto out; - ret = new->wd; - - get_inotify_handle(ih); - - new->inode = igrab(old->inode); - - list_add(&new->h_list, &ih->watches); - list_add(&new->i_list, &old->inode->inotify_watches); -out: - mutex_unlock(&ih->mutex); - return ret; -} - -void inotify_evict_watch(struct inotify_watch *watch) -{ - get_inotify_watch(watch); - mutex_lock(&watch->ih->mutex); - inotify_remove_watch_locked(watch->ih, watch); - mutex_unlock(&watch->ih->mutex); -} - -/** - * inotify_rm_wd - remove a watch from an inotify instance - * @ih: inotify handle - * @wd: watch descriptor to remove - * - * Can sleep. - */ -int inotify_rm_wd(struct inotify_handle *ih, u32 wd) -{ - struct inotify_watch *watch; - struct super_block *sb; - struct inode *inode; - int how; - - mutex_lock(&ih->mutex); - watch = idr_find(&ih->idr, wd); - if (unlikely(!watch)) { - mutex_unlock(&ih->mutex); - return -EINVAL; - } - sb = watch->inode->i_sb; - how = pin_to_kill(ih, watch); - if (!how) - return 0; - - inode = watch->inode; - - mutex_lock(&inode->inotify_mutex); - mutex_lock(&ih->mutex); - - /* make sure that we did not race */ - if (likely(idr_find(&ih->idr, wd) == watch)) - inotify_remove_watch_locked(ih, watch); - - mutex_unlock(&ih->mutex); - mutex_unlock(&inode->inotify_mutex); - unpin_and_kill(watch, how); - - return 0; -} -EXPORT_SYMBOL_GPL(inotify_rm_wd); - -/** - * inotify_rm_watch - remove a watch from an inotify instance - * @ih: inotify handle - * @watch: watch to remove - * - * Can sleep. - */ -int inotify_rm_watch(struct inotify_handle *ih, - struct inotify_watch *watch) -{ - return inotify_rm_wd(ih, watch->wd); -} -EXPORT_SYMBOL_GPL(inotify_rm_watch); - -/* - * inotify_setup - core initialization function - */ -static int __init inotify_setup(void) -{ - BUILD_BUG_ON(IN_ACCESS != FS_ACCESS); - BUILD_BUG_ON(IN_MODIFY != FS_MODIFY); - BUILD_BUG_ON(IN_ATTRIB != FS_ATTRIB); - BUILD_BUG_ON(IN_CLOSE_WRITE != FS_CLOSE_WRITE); - BUILD_BUG_ON(IN_CLOSE_NOWRITE != FS_CLOSE_NOWRITE); - BUILD_BUG_ON(IN_OPEN != FS_OPEN); - BUILD_BUG_ON(IN_MOVED_FROM != FS_MOVED_FROM); - BUILD_BUG_ON(IN_MOVED_TO != FS_MOVED_TO); - BUILD_BUG_ON(IN_CREATE != FS_CREATE); - BUILD_BUG_ON(IN_DELETE != FS_DELETE); - BUILD_BUG_ON(IN_DELETE_SELF != FS_DELETE_SELF); - BUILD_BUG_ON(IN_MOVE_SELF != FS_MOVE_SELF); - BUILD_BUG_ON(IN_Q_OVERFLOW != FS_Q_OVERFLOW); - - BUILD_BUG_ON(IN_UNMOUNT != FS_UNMOUNT); - BUILD_BUG_ON(IN_ISDIR != FS_IN_ISDIR); - BUILD_BUG_ON(IN_IGNORED != FS_IN_IGNORED); - BUILD_BUG_ON(IN_ONESHOT != FS_IN_ONESHOT); - - atomic_set(&inotify_cookie, 0); - - return 0; -} - -module_init(inotify_setup); diff --git a/fs/notify/inotify/inotify.h b/fs/notify/inotify/inotify.h index f234f3a4c8c..ed855ef6f07 100644 --- a/fs/notify/inotify/inotify.h +++ b/fs/notify/inotify/inotify.h @@ -2,21 +2,31 @@ #include <linux/inotify.h> #include <linux/slab.h> /* struct kmem_cache */ -extern struct kmem_cache *event_priv_cachep; - -struct inotify_event_private_data { - struct fsnotify_event_private_data fsnotify_event_priv_data; +struct inotify_event_info { + struct fsnotify_event fse; int wd; + u32 sync_cookie; + int name_len; + char name[]; }; -struct inotify_inode_mark_entry { - /* fsnotify_mark_entry MUST be the first thing */ - struct fsnotify_mark_entry fsn_entry; +struct inotify_inode_mark { + struct fsnotify_mark fsn_mark; int wd; }; -extern void inotify_ignored_and_remove_idr(struct fsnotify_mark_entry *entry, +static inline struct inotify_event_info *INOTIFY_E(struct fsnotify_event *fse) +{ + return container_of(fse, struct inotify_event_info, fse); +} + +extern void inotify_ignored_and_remove_idr(struct fsnotify_mark *fsn_mark, struct fsnotify_group *group); -extern void inotify_free_event_priv(struct fsnotify_event_private_data *event_priv); +extern int inotify_handle_event(struct fsnotify_group *group, + struct inode *inode, + struct fsnotify_mark *inode_mark, + struct fsnotify_mark *vfsmount_mark, + u32 mask, void *data, int data_type, + const unsigned char *file_name, u32 cookie); extern const struct fsnotify_ops inotify_fsnotify_ops; diff --git a/fs/notify/inotify/inotify_fsnotify.c b/fs/notify/inotify/inotify_fsnotify.c index 1afb0a10229..43ab1e1a07a 100644 --- a/fs/notify/inotify/inotify_fsnotify.c +++ b/fs/notify/inotify/inotify_fsnotify.c @@ -22,87 +22,107 @@ * General Public License for more details. */ +#include <linux/dcache.h> /* d_unlinked */ #include <linux/fs.h> /* struct inode */ #include <linux/fsnotify_backend.h> #include <linux/inotify.h> #include <linux/path.h> /* struct path */ #include <linux/slab.h> /* kmem_* */ #include <linux/types.h> +#include <linux/sched.h> #include "inotify.h" -static int inotify_handle_event(struct fsnotify_group *group, struct fsnotify_event *event) +/* + * Check if 2 events contain the same information. + */ +static bool event_compare(struct fsnotify_event *old_fsn, + struct fsnotify_event *new_fsn) { - struct fsnotify_mark_entry *entry; - struct inotify_inode_mark_entry *ientry; - struct inode *to_tell; - struct inotify_event_private_data *event_priv; - struct fsnotify_event_private_data *fsn_event_priv; - int wd, ret; - - to_tell = event->to_tell; - - spin_lock(&to_tell->i_lock); - entry = fsnotify_find_mark_entry(group, to_tell); - spin_unlock(&to_tell->i_lock); - /* race with watch removal? We already passes should_send */ - if (unlikely(!entry)) - return 0; - ientry = container_of(entry, struct inotify_inode_mark_entry, - fsn_entry); - wd = ientry->wd; + struct inotify_event_info *old, *new; - event_priv = kmem_cache_alloc(event_priv_cachep, GFP_KERNEL); - if (unlikely(!event_priv)) - return -ENOMEM; + if (old_fsn->mask & FS_IN_IGNORED) + return false; + old = INOTIFY_E(old_fsn); + new = INOTIFY_E(new_fsn); + if ((old_fsn->mask == new_fsn->mask) && + (old_fsn->inode == new_fsn->inode) && + (old->name_len == new->name_len) && + (!old->name_len || !strcmp(old->name, new->name))) + return true; + return false; +} - fsn_event_priv = &event_priv->fsnotify_event_priv_data; +static int inotify_merge(struct list_head *list, + struct fsnotify_event *event) +{ + struct fsnotify_event *last_event; - fsn_event_priv->group = group; - event_priv->wd = wd; + last_event = list_entry(list->prev, struct fsnotify_event, list); + return event_compare(last_event, event); +} - ret = fsnotify_add_notify_event(group, event, fsn_event_priv); - if (ret) { - inotify_free_event_priv(fsn_event_priv); - /* EEXIST says we tail matched, EOVERFLOW isn't something - * to report up the stack. */ - if ((ret == -EEXIST) || - (ret == -EOVERFLOW)) - ret = 0; +int inotify_handle_event(struct fsnotify_group *group, + struct inode *inode, + struct fsnotify_mark *inode_mark, + struct fsnotify_mark *vfsmount_mark, + u32 mask, void *data, int data_type, + const unsigned char *file_name, u32 cookie) +{ + struct inotify_inode_mark *i_mark; + struct inotify_event_info *event; + struct fsnotify_event *fsn_event; + int ret; + int len = 0; + int alloc_len = sizeof(struct inotify_event_info); + + BUG_ON(vfsmount_mark); + + if ((inode_mark->mask & FS_EXCL_UNLINK) && + (data_type == FSNOTIFY_EVENT_PATH)) { + struct path *path = data; + + if (d_unlinked(path->dentry)) + return 0; + } + if (file_name) { + len = strlen(file_name); + alloc_len += len + 1; } - /* - * If we hold the entry until after the event is on the queue - * IN_IGNORED won't be able to pass this event in the queue - */ - fsnotify_put_mark(entry); + pr_debug("%s: group=%p inode=%p mask=%x\n", __func__, group, inode, + mask); - return ret; -} + i_mark = container_of(inode_mark, struct inotify_inode_mark, + fsn_mark); -static void inotify_freeing_mark(struct fsnotify_mark_entry *entry, struct fsnotify_group *group) -{ - inotify_ignored_and_remove_idr(entry, group); -} + event = kmalloc(alloc_len, GFP_KERNEL); + if (unlikely(!event)) + return -ENOMEM; -static bool inotify_should_send_event(struct fsnotify_group *group, struct inode *inode, __u32 mask) -{ - struct fsnotify_mark_entry *entry; - bool send; + fsn_event = &event->fse; + fsnotify_init_event(fsn_event, inode, mask); + event->wd = i_mark->wd; + event->sync_cookie = cookie; + event->name_len = len; + if (len) + strcpy(event->name, file_name); - spin_lock(&inode->i_lock); - entry = fsnotify_find_mark_entry(group, inode); - spin_unlock(&inode->i_lock); - if (!entry) - return false; + ret = fsnotify_add_notify_event(group, fsn_event, inotify_merge); + if (ret) { + /* Our event wasn't used in the end. Free it. */ + fsnotify_destroy_event(group, fsn_event); + } - mask = (mask & ~FS_EVENT_ON_CHILD); - send = (entry->mask & mask); + if (inode_mark->mask & IN_ONESHOT) + fsnotify_destroy_mark(inode_mark, group); - /* find took a reference */ - fsnotify_put_mark(entry); + return 0; +} - return send; +static void inotify_freeing_mark(struct fsnotify_mark *fsn_mark, struct fsnotify_group *group) +{ + inotify_ignored_and_remove_idr(fsn_mark, group); } /* @@ -114,18 +134,18 @@ static bool inotify_should_send_event(struct fsnotify_group *group, struct inode */ static int idr_callback(int id, void *p, void *data) { - struct fsnotify_mark_entry *entry; - struct inotify_inode_mark_entry *ientry; + struct fsnotify_mark *fsn_mark; + struct inotify_inode_mark *i_mark; static bool warned = false; if (warned) return 0; warned = true; - entry = p; - ientry = container_of(entry, struct inotify_inode_mark_entry, fsn_entry); + fsn_mark = p; + i_mark = container_of(fsn_mark, struct inotify_inode_mark, fsn_mark); - WARN(1, "inotify closing but id=%d for entry=%p in group=%p still in " + WARN(1, "inotify closing but id=%d for fsn_mark=%p in group=%p still in " "idr. Probably leaking memory\n", id, p, data); /* @@ -134,35 +154,29 @@ static int idr_callback(int id, void *p, void *data) * out why we got here and the panic is no worse than the original * BUG() that was here. */ - if (entry) - printk(KERN_WARNING "entry->group=%p inode=%p wd=%d\n", - entry->group, entry->inode, ientry->wd); + if (fsn_mark) + printk(KERN_WARNING "fsn_mark->group=%p inode=%p wd=%d\n", + fsn_mark->group, fsn_mark->i.inode, i_mark->wd); return 0; } static void inotify_free_group_priv(struct fsnotify_group *group) { - /* ideally the idr is empty and we won't hit the BUG in teh callback */ + /* ideally the idr is empty and we won't hit the BUG in the callback */ idr_for_each(&group->inotify_data.idr, idr_callback, group); - idr_remove_all(&group->inotify_data.idr); idr_destroy(&group->inotify_data.idr); + atomic_dec(&group->inotify_data.user->inotify_devs); + free_uid(group->inotify_data.user); } -void inotify_free_event_priv(struct fsnotify_event_private_data *fsn_event_priv) +static void inotify_free_event(struct fsnotify_event *fsn_event) { - struct inotify_event_private_data *event_priv; - - - event_priv = container_of(fsn_event_priv, struct inotify_event_private_data, - fsnotify_event_priv_data); - - kmem_cache_free(event_priv_cachep, event_priv); + kfree(INOTIFY_E(fsn_event)); } const struct fsnotify_ops inotify_fsnotify_ops = { .handle_event = inotify_handle_event, - .should_send_event = inotify_should_send_event, .free_group_priv = inotify_free_group_priv, - .free_event_priv = inotify_free_event_priv, + .free_event = inotify_free_event, .freeing_mark = inotify_freeing_mark, }; diff --git a/fs/notify/inotify/inotify_user.c b/fs/notify/inotify/inotify_user.c index 472cdf29ef8..cc423a30a0c 100644 --- a/fs/notify/inotify/inotify_user.c +++ b/fs/notify/inotify/inotify_user.c @@ -40,22 +40,16 @@ #include <linux/wait.h> #include "inotify.h" +#include "../fdinfo.h" #include <asm/ioctls.h> /* these are configurable via /proc/sys/fs/inotify/ */ static int inotify_max_user_instances __read_mostly; static int inotify_max_queued_events __read_mostly; -int inotify_max_user_watches __read_mostly; +static int inotify_max_user_watches __read_mostly; static struct kmem_cache *inotify_inode_mark_cachep __read_mostly; -struct kmem_cache *event_priv_cachep __read_mostly; - -/* - * When inotify registers a new group it increments this and uses that - * value as an offset to set the fsnotify group "name" and priority. - */ -static atomic_t inotify_grp_num; #ifdef CONFIG_SYSCTL @@ -63,7 +57,7 @@ static atomic_t inotify_grp_num; static int zero; -ctl_table inotify_table[] = { +struct ctl_table inotify_table[] = { { .procname = "max_user_instances", .data = &inotify_max_user_instances, @@ -96,11 +90,14 @@ static inline __u32 inotify_arg_to_mask(u32 arg) { __u32 mask; - /* everything should accept their own ignored and cares about children */ - mask = (FS_IN_IGNORED | FS_EVENT_ON_CHILD); + /* + * everything should accept their own ignored, cares about children, + * and should receive events when the inode is unmounted + */ + mask = (FS_IN_IGNORED | FS_EVENT_ON_CHILD | FS_UNMOUNT); /* mask off the flags used to open the fd */ - mask |= (arg & (IN_ALL_EVENTS | IN_ONESHOT)); + mask |= (arg & (IN_ALL_EVENTS | IN_ONESHOT | IN_EXCL_UNLINK)); return mask; } @@ -126,6 +123,16 @@ static unsigned int inotify_poll(struct file *file, poll_table *wait) return ret; } +static int round_event_name_len(struct fsnotify_event *fsn_event) +{ + struct inotify_event_info *event; + + event = INOTIFY_E(fsn_event); + if (!event->name_len) + return 0; + return roundup(event->name_len + 1, sizeof(struct inotify_event)); +} + /* * Get an inotify_kernel_event if one exists and is small * enough to fit in "count". Return an error pointer if @@ -144,9 +151,9 @@ static struct fsnotify_event *get_one_event(struct fsnotify_group *group, event = fsnotify_peek_notify_event(group); - if (event->name_len) - event_size += roundup(event->name_len + 1, event_size); + pr_debug("%s: group=%p event=%p\n", __func__, group, event); + event_size += round_event_name_len(event); if (event_size > count) return ERR_PTR(-EINVAL); @@ -164,38 +171,27 @@ static struct fsnotify_event *get_one_event(struct fsnotify_group *group, * buffer we had in "get_one_event()" above. */ static ssize_t copy_event_to_user(struct fsnotify_group *group, - struct fsnotify_event *event, + struct fsnotify_event *fsn_event, char __user *buf) { struct inotify_event inotify_event; - struct fsnotify_event_private_data *fsn_priv; - struct inotify_event_private_data *priv; + struct inotify_event_info *event; size_t event_size = sizeof(struct inotify_event); - size_t name_len = 0; - - /* we get the inotify watch descriptor from the event private data */ - spin_lock(&event->lock); - fsn_priv = fsnotify_remove_priv_from_event(group, event); - spin_unlock(&event->lock); - - if (!fsn_priv) - inotify_event.wd = -1; - else { - priv = container_of(fsn_priv, struct inotify_event_private_data, - fsnotify_event_priv_data); - inotify_event.wd = priv->wd; - inotify_free_event_priv(fsn_priv); - } + size_t name_len; + size_t pad_name_len; + + pr_debug("%s: group=%p event=%p\n", __func__, group, fsn_event); + event = INOTIFY_E(fsn_event); + name_len = event->name_len; /* - * round up event->name_len so it is a multiple of event_size + * round up name length so it is a multiple of event_size * plus an extra byte for the terminating '\0'. */ - if (event->name_len) - name_len = roundup(event->name_len + 1, event_size); - inotify_event.len = name_len; - - inotify_event.mask = inotify_mask_to_arg(event->mask); + pad_name_len = round_event_name_len(fsn_event); + inotify_event.len = pad_name_len; + inotify_event.mask = inotify_mask_to_arg(fsn_event->mask); + inotify_event.wd = event->wd; inotify_event.cookie = event->sync_cookie; /* send the main event */ @@ -207,20 +203,18 @@ static ssize_t copy_event_to_user(struct fsnotify_group *group, /* * fsnotify only stores the pathname, so here we have to send the pathname * and then pad that pathname out to a multiple of sizeof(inotify_event) - * with zeros. I get my zeros from the nul_inotify_event. + * with zeros. */ - if (name_len) { - unsigned int len_to_zero = name_len - event->name_len; + if (pad_name_len) { /* copy the path name */ - if (copy_to_user(buf, event->file_name, event->name_len)) + if (copy_to_user(buf, event->name, name_len)) return -EFAULT; - buf += event->name_len; + buf += name_len; /* fill userspace with 0's */ - if (clear_user(buf, len_to_zero)) + if (clear_user(buf, pad_name_len - name_len)) return -EFAULT; - buf += len_to_zero; - event_size += name_len; + event_size += pad_name_len; } return event_size; @@ -245,12 +239,14 @@ static ssize_t inotify_read(struct file *file, char __user *buf, kevent = get_one_event(group, count); mutex_unlock(&group->notification_mutex); + pr_debug("%s: group=%p kevent=%p\n", __func__, group, kevent); + if (kevent) { ret = PTR_ERR(kevent); if (IS_ERR(kevent)) break; ret = copy_event_to_user(group, kevent, buf); - fsnotify_put_event(kevent); + fsnotify_destroy_event(group, kevent); if (ret < 0) break; buf += ret; @@ -261,7 +257,7 @@ static ssize_t inotify_read(struct file *file, char __user *buf, ret = -EAGAIN; if (file->f_flags & O_NONBLOCK) break; - ret = -EINTR; + ret = -ERESTARTSYS; if (signal_pending(current)) break; @@ -277,24 +273,14 @@ static ssize_t inotify_read(struct file *file, char __user *buf, return ret; } -static int inotify_fasync(int fd, struct file *file, int on) -{ - struct fsnotify_group *group = file->private_data; - - return fasync_helper(fd, file, on, &group->inotify_data.fa) >= 0 ? 0 : -EIO; -} - static int inotify_release(struct inode *ignored, struct file *file) { struct fsnotify_group *group = file->private_data; - struct user_struct *user = group->inotify_data.user; - fsnotify_clear_marks_by_group(group); + pr_debug("%s: group=%p\n", __func__, group); /* free this group, matching get was inotify_init->fsnotify_obtain_group */ - fsnotify_put_group(group); - - atomic_dec(&user->inotify_devs); + fsnotify_destroy_group(group); return 0; } @@ -303,8 +289,7 @@ static long inotify_ioctl(struct file *file, unsigned int cmd, unsigned long arg) { struct fsnotify_group *group; - struct fsnotify_event_holder *holder; - struct fsnotify_event *event; + struct fsnotify_event *fsn_event; void __user *p; int ret = -ENOTTY; size_t send_len = 0; @@ -312,15 +297,15 @@ static long inotify_ioctl(struct file *file, unsigned int cmd, group = file->private_data; p = (void __user *) arg; + pr_debug("%s: group=%p cmd=%u\n", __func__, group, cmd); + switch (cmd) { case FIONREAD: mutex_lock(&group->notification_mutex); - list_for_each_entry(holder, &group->notification_list, event_list) { - event = holder->event; + list_for_each_entry(fsn_event, &group->notification_list, + list) { send_len += sizeof(struct inotify_event); - if (event->name_len) - send_len += roundup(event->name_len + 1, - sizeof(struct inotify_event)); + send_len += round_event_name_len(fsn_event); } mutex_unlock(&group->notification_mutex); ret = put_user(send_len, (int __user *) p); @@ -331,12 +316,14 @@ static long inotify_ioctl(struct file *file, unsigned int cmd, } static const struct file_operations inotify_fops = { + .show_fdinfo = inotify_show_fdinfo, .poll = inotify_poll, .read = inotify_read, - .fasync = inotify_fasync, + .fasync = fsnotify_fasync, .release = inotify_release, .unlocked_ioctl = inotify_ioctl, .compat_ioctl = inotify_ioctl, + .llseek = noop_llseek, }; @@ -357,162 +344,223 @@ static int inotify_find_inode(const char __user *dirname, struct path *path, uns return error; } +static int inotify_add_to_idr(struct idr *idr, spinlock_t *idr_lock, + struct inotify_inode_mark *i_mark) +{ + int ret; + + idr_preload(GFP_KERNEL); + spin_lock(idr_lock); + + ret = idr_alloc_cyclic(idr, i_mark, 1, 0, GFP_NOWAIT); + if (ret >= 0) { + /* we added the mark to the idr, take a reference */ + i_mark->wd = ret; + fsnotify_get_mark(&i_mark->fsn_mark); + } + + spin_unlock(idr_lock); + idr_preload_end(); + return ret < 0 ? ret : 0; +} + +static struct inotify_inode_mark *inotify_idr_find_locked(struct fsnotify_group *group, + int wd) +{ + struct idr *idr = &group->inotify_data.idr; + spinlock_t *idr_lock = &group->inotify_data.idr_lock; + struct inotify_inode_mark *i_mark; + + assert_spin_locked(idr_lock); + + i_mark = idr_find(idr, wd); + if (i_mark) { + struct fsnotify_mark *fsn_mark = &i_mark->fsn_mark; + + fsnotify_get_mark(fsn_mark); + /* One ref for being in the idr, one ref we just took */ + BUG_ON(atomic_read(&fsn_mark->refcnt) < 2); + } + + return i_mark; +} + +static struct inotify_inode_mark *inotify_idr_find(struct fsnotify_group *group, + int wd) +{ + struct inotify_inode_mark *i_mark; + spinlock_t *idr_lock = &group->inotify_data.idr_lock; + + spin_lock(idr_lock); + i_mark = inotify_idr_find_locked(group, wd); + spin_unlock(idr_lock); + + return i_mark; +} + +static void do_inotify_remove_from_idr(struct fsnotify_group *group, + struct inotify_inode_mark *i_mark) +{ + struct idr *idr = &group->inotify_data.idr; + spinlock_t *idr_lock = &group->inotify_data.idr_lock; + int wd = i_mark->wd; + + assert_spin_locked(idr_lock); + + idr_remove(idr, wd); + + /* removed from the idr, drop that ref */ + fsnotify_put_mark(&i_mark->fsn_mark); +} + /* * Remove the mark from the idr (if present) and drop the reference * on the mark because it was in the idr. */ static void inotify_remove_from_idr(struct fsnotify_group *group, - struct inotify_inode_mark_entry *ientry) + struct inotify_inode_mark *i_mark) { - struct idr *idr; - struct fsnotify_mark_entry *entry; - struct inotify_inode_mark_entry *found_ientry; + spinlock_t *idr_lock = &group->inotify_data.idr_lock; + struct inotify_inode_mark *found_i_mark = NULL; int wd; - spin_lock(&group->inotify_data.idr_lock); - idr = &group->inotify_data.idr; - wd = ientry->wd; + spin_lock(idr_lock); + wd = i_mark->wd; - if (wd == -1) + /* + * does this i_mark think it is in the idr? we shouldn't get called + * if it wasn't.... + */ + if (wd == -1) { + WARN_ONCE(1, "%s: i_mark=%p i_mark->wd=%d i_mark->group=%p" + " i_mark->inode=%p\n", __func__, i_mark, i_mark->wd, + i_mark->fsn_mark.group, i_mark->fsn_mark.i.inode); goto out; + } - entry = idr_find(&group->inotify_data.idr, wd); - if (unlikely(!entry)) + /* Lets look in the idr to see if we find it */ + found_i_mark = inotify_idr_find_locked(group, wd); + if (unlikely(!found_i_mark)) { + WARN_ONCE(1, "%s: i_mark=%p i_mark->wd=%d i_mark->group=%p" + " i_mark->inode=%p\n", __func__, i_mark, i_mark->wd, + i_mark->fsn_mark.group, i_mark->fsn_mark.i.inode); goto out; + } - found_ientry = container_of(entry, struct inotify_inode_mark_entry, fsn_entry); - if (unlikely(found_ientry != ientry)) { - /* We found an entry in the idr with the right wd, but it's - * not the entry we were told to remove. eparis seriously - * fucked up somewhere. */ - WARN_ON(1); - ientry->wd = -1; + /* + * We found an mark in the idr at the right wd, but it's + * not the mark we were told to remove. eparis seriously + * fucked up somewhere. + */ + if (unlikely(found_i_mark != i_mark)) { + WARN_ONCE(1, "%s: i_mark=%p i_mark->wd=%d i_mark->group=%p " + "mark->inode=%p found_i_mark=%p found_i_mark->wd=%d " + "found_i_mark->group=%p found_i_mark->inode=%p\n", + __func__, i_mark, i_mark->wd, i_mark->fsn_mark.group, + i_mark->fsn_mark.i.inode, found_i_mark, found_i_mark->wd, + found_i_mark->fsn_mark.group, + found_i_mark->fsn_mark.i.inode); goto out; } - /* One ref for being in the idr, one ref held by the caller */ - BUG_ON(atomic_read(&entry->refcnt) < 2); - - idr_remove(idr, wd); - ientry->wd = -1; + /* + * One ref for being in the idr + * one ref held by the caller trying to kill us + * one ref grabbed by inotify_idr_find + */ + if (unlikely(atomic_read(&i_mark->fsn_mark.refcnt) < 3)) { + printk(KERN_ERR "%s: i_mark=%p i_mark->wd=%d i_mark->group=%p" + " i_mark->inode=%p\n", __func__, i_mark, i_mark->wd, + i_mark->fsn_mark.group, i_mark->fsn_mark.i.inode); + /* we can't really recover with bad ref cnting.. */ + BUG(); + } - /* removed from the idr, drop that ref */ - fsnotify_put_mark(entry); + do_inotify_remove_from_idr(group, i_mark); out: - spin_unlock(&group->inotify_data.idr_lock); + /* match the ref taken by inotify_idr_find_locked() */ + if (found_i_mark) + fsnotify_put_mark(&found_i_mark->fsn_mark); + i_mark->wd = -1; + spin_unlock(idr_lock); } /* * Send IN_IGNORED for this wd, remove this wd from the idr. */ -void inotify_ignored_and_remove_idr(struct fsnotify_mark_entry *entry, +void inotify_ignored_and_remove_idr(struct fsnotify_mark *fsn_mark, struct fsnotify_group *group) { - struct inotify_inode_mark_entry *ientry; - struct fsnotify_event *ignored_event; - struct inotify_event_private_data *event_priv; - struct fsnotify_event_private_data *fsn_event_priv; - int ret; - - ignored_event = fsnotify_create_event(NULL, FS_IN_IGNORED, NULL, - FSNOTIFY_EVENT_NONE, NULL, 0, - GFP_NOFS); - if (!ignored_event) - return; - - ientry = container_of(entry, struct inotify_inode_mark_entry, fsn_entry); - - event_priv = kmem_cache_alloc(event_priv_cachep, GFP_NOFS); - if (unlikely(!event_priv)) - goto skip_send_ignore; - - fsn_event_priv = &event_priv->fsnotify_event_priv_data; - - fsn_event_priv->group = group; - event_priv->wd = ientry->wd; - - ret = fsnotify_add_notify_event(group, ignored_event, fsn_event_priv); - if (ret) - inotify_free_event_priv(fsn_event_priv); - -skip_send_ignore: + struct inotify_inode_mark *i_mark; - /* matches the reference taken when the event was created */ - fsnotify_put_event(ignored_event); + /* Queue ignore event for the watch */ + inotify_handle_event(group, NULL, fsn_mark, NULL, FS_IN_IGNORED, + NULL, FSNOTIFY_EVENT_NONE, NULL, 0); - /* remove this entry from the idr */ - inotify_remove_from_idr(group, ientry); + i_mark = container_of(fsn_mark, struct inotify_inode_mark, fsn_mark); + /* remove this mark from the idr */ + inotify_remove_from_idr(group, i_mark); atomic_dec(&group->inotify_data.user->inotify_watches); } /* ding dong the mark is dead */ -static void inotify_free_mark(struct fsnotify_mark_entry *entry) +static void inotify_free_mark(struct fsnotify_mark *fsn_mark) { - struct inotify_inode_mark_entry *ientry = (struct inotify_inode_mark_entry *)entry; + struct inotify_inode_mark *i_mark; - kmem_cache_free(inotify_inode_mark_cachep, ientry); + i_mark = container_of(fsn_mark, struct inotify_inode_mark, fsn_mark); + + kmem_cache_free(inotify_inode_mark_cachep, i_mark); } static int inotify_update_existing_watch(struct fsnotify_group *group, struct inode *inode, u32 arg) { - struct fsnotify_mark_entry *entry; - struct inotify_inode_mark_entry *ientry; + struct fsnotify_mark *fsn_mark; + struct inotify_inode_mark *i_mark; __u32 old_mask, new_mask; __u32 mask; int add = (arg & IN_MASK_ADD); int ret; - /* don't allow invalid bits: we don't want flags set */ mask = inotify_arg_to_mask(arg); - if (unlikely(!mask)) - return -EINVAL; - spin_lock(&inode->i_lock); - entry = fsnotify_find_mark_entry(group, inode); - spin_unlock(&inode->i_lock); - if (!entry) + fsn_mark = fsnotify_find_inode_mark(group, inode); + if (!fsn_mark) return -ENOENT; - ientry = container_of(entry, struct inotify_inode_mark_entry, fsn_entry); + i_mark = container_of(fsn_mark, struct inotify_inode_mark, fsn_mark); - spin_lock(&entry->lock); + spin_lock(&fsn_mark->lock); - old_mask = entry->mask; - if (add) { - entry->mask |= mask; - new_mask = entry->mask; - } else { - entry->mask = mask; - new_mask = entry->mask; - } + old_mask = fsn_mark->mask; + if (add) + fsnotify_set_mark_mask_locked(fsn_mark, (fsn_mark->mask | mask)); + else + fsnotify_set_mark_mask_locked(fsn_mark, mask); + new_mask = fsn_mark->mask; - spin_unlock(&entry->lock); + spin_unlock(&fsn_mark->lock); if (old_mask != new_mask) { /* more bits in old than in new? */ int dropped = (old_mask & ~new_mask); - /* more bits in this entry than the inode's mask? */ + /* more bits in this fsn_mark than the inode's mask? */ int do_inode = (new_mask & ~inode->i_fsnotify_mask); - /* more bits in this entry than the group? */ - int do_group = (new_mask & ~group->mask); - /* update the inode with this new entry */ + /* update the inode with this new fsn_mark */ if (dropped || do_inode) fsnotify_recalc_inode_mask(inode); - /* update the group mask with the new mask */ - if (dropped || do_group) - fsnotify_recalc_group_mask(group); } /* return the wd */ - ret = ientry->wd; + ret = i_mark->wd; - /* match the get from fsnotify_find_mark_entry() */ - fsnotify_put_mark(entry); + /* match the get from fsnotify_find_mark() */ + fsnotify_put_mark(fsn_mark); return ret; } @@ -521,73 +569,48 @@ static int inotify_new_watch(struct fsnotify_group *group, struct inode *inode, u32 arg) { - struct inotify_inode_mark_entry *tmp_ientry; + struct inotify_inode_mark *tmp_i_mark; __u32 mask; int ret; + struct idr *idr = &group->inotify_data.idr; + spinlock_t *idr_lock = &group->inotify_data.idr_lock; - /* don't allow invalid bits: we don't want flags set */ mask = inotify_arg_to_mask(arg); - if (unlikely(!mask)) - return -EINVAL; - tmp_ientry = kmem_cache_alloc(inotify_inode_mark_cachep, GFP_KERNEL); - if (unlikely(!tmp_ientry)) + tmp_i_mark = kmem_cache_alloc(inotify_inode_mark_cachep, GFP_KERNEL); + if (unlikely(!tmp_i_mark)) return -ENOMEM; - fsnotify_init_mark(&tmp_ientry->fsn_entry, inotify_free_mark); - tmp_ientry->fsn_entry.mask = mask; - tmp_ientry->wd = -1; + fsnotify_init_mark(&tmp_i_mark->fsn_mark, inotify_free_mark); + tmp_i_mark->fsn_mark.mask = mask; + tmp_i_mark->wd = -1; ret = -ENOSPC; if (atomic_read(&group->inotify_data.user->inotify_watches) >= inotify_max_user_watches) goto out_err; -retry: - ret = -ENOMEM; - if (unlikely(!idr_pre_get(&group->inotify_data.idr, GFP_KERNEL))) - goto out_err; - spin_lock(&group->inotify_data.idr_lock); - ret = idr_get_new_above(&group->inotify_data.idr, &tmp_ientry->fsn_entry, - group->inotify_data.last_wd+1, - &tmp_ientry->wd); - spin_unlock(&group->inotify_data.idr_lock); - if (ret) { - /* idr was out of memory allocate and try again */ - if (ret == -EAGAIN) - goto retry; + ret = inotify_add_to_idr(idr, idr_lock, tmp_i_mark); + if (ret) goto out_err; - } - - /* we put the mark on the idr, take a reference */ - fsnotify_get_mark(&tmp_ientry->fsn_entry); /* we are on the idr, now get on the inode */ - ret = fsnotify_add_mark(&tmp_ientry->fsn_entry, group, inode); + ret = fsnotify_add_mark_locked(&tmp_i_mark->fsn_mark, group, inode, + NULL, 0); if (ret) { /* we failed to get on the inode, get off the idr */ - inotify_remove_from_idr(group, tmp_ientry); + inotify_remove_from_idr(group, tmp_i_mark); goto out_err; } - /* update the idr hint, who cares about races, it's just a hint */ - group->inotify_data.last_wd = tmp_ientry->wd; - /* increment the number of watches the user has */ atomic_inc(&group->inotify_data.user->inotify_watches); - /* return the watch descriptor for this new entry */ - ret = tmp_ientry->wd; - - /* match the ref from fsnotify_init_markentry() */ - fsnotify_put_mark(&tmp_ientry->fsn_entry); - - /* if this mark added a new event update the group mask */ - if (mask & ~group->mask) - fsnotify_recalc_group_mask(group); + /* return the watch descriptor for this new mark */ + ret = tmp_i_mark->wd; out_err: - if (ret < 0) - kmem_cache_free(inotify_inode_mark_cachep, tmp_ientry); + /* match the ref from fsnotify_init_mark() */ + fsnotify_put_mark(&tmp_i_mark->fsn_mark); return ret; } @@ -596,41 +619,48 @@ static int inotify_update_watch(struct fsnotify_group *group, struct inode *inod { int ret = 0; -retry: + mutex_lock(&group->mark_mutex); /* try to update and existing watch with the new arg */ ret = inotify_update_existing_watch(group, inode, arg); /* no mark present, try to add a new one */ if (ret == -ENOENT) ret = inotify_new_watch(group, inode, arg); - /* - * inotify_new_watch could race with another thread which did an - * inotify_new_watch between the update_existing and the add watch - * here, go back and try to update an existing mark again. - */ - if (ret == -EEXIST) - goto retry; + mutex_unlock(&group->mark_mutex); return ret; } -static struct fsnotify_group *inotify_new_group(struct user_struct *user, unsigned int max_events) +static struct fsnotify_group *inotify_new_group(unsigned int max_events) { struct fsnotify_group *group; - unsigned int grp_num; + struct inotify_event_info *oevent; - /* fsnotify_obtain_group took a reference to group, we put this when we kill the file in the end */ - grp_num = (INOTIFY_GROUP_NUM - atomic_inc_return(&inotify_grp_num)); - group = fsnotify_obtain_group(grp_num, 0, &inotify_fsnotify_ops); + group = fsnotify_alloc_group(&inotify_fsnotify_ops); if (IS_ERR(group)) return group; + oevent = kmalloc(sizeof(struct inotify_event_info), GFP_KERNEL); + if (unlikely(!oevent)) { + fsnotify_destroy_group(group); + return ERR_PTR(-ENOMEM); + } + group->overflow_event = &oevent->fse; + fsnotify_init_event(group->overflow_event, NULL, FS_Q_OVERFLOW); + oevent->wd = -1; + oevent->sync_cookie = 0; + oevent->name_len = 0; + group->max_events = max_events; spin_lock_init(&group->inotify_data.idr_lock); idr_init(&group->inotify_data.idr); - group->inotify_data.last_wd = 0; - group->inotify_data.user = user; - group->inotify_data.fa = NULL; + group->inotify_data.user = get_current_user(); + + if (atomic_inc_return(&group->inotify_data.user->inotify_devs) > + inotify_max_user_instances) { + fsnotify_destroy_group(group); + return ERR_PTR(-EMFILE); + } return group; } @@ -640,7 +670,6 @@ static struct fsnotify_group *inotify_new_group(struct user_struct *user, unsign SYSCALL_DEFINE1(inotify_init1, int, flags) { struct fsnotify_group *group; - struct user_struct *user; int ret; /* Check the IN_* constants for consistency. */ @@ -650,30 +679,16 @@ SYSCALL_DEFINE1(inotify_init1, int, flags) if (flags & ~(IN_CLOEXEC | IN_NONBLOCK)) return -EINVAL; - user = get_current_user(); - if (unlikely(atomic_read(&user->inotify_devs) >= - inotify_max_user_instances)) { - ret = -EMFILE; - goto out_free_uid; - } - /* fsnotify_obtain_group took a reference to group, we put this when we kill the file in the end */ - group = inotify_new_group(user, inotify_max_queued_events); - if (IS_ERR(group)) { - ret = PTR_ERR(group); - goto out_free_uid; - } - - atomic_inc(&user->inotify_devs); + group = inotify_new_group(inotify_max_queued_events); + if (IS_ERR(group)) + return PTR_ERR(group); ret = anon_inode_getfd("inotify", &inotify_fops, group, O_RDONLY | flags); - if (ret >= 0) - return ret; + if (ret < 0) + fsnotify_destroy_group(group); - atomic_dec(&user->inotify_devs); -out_free_uid: - free_uid(user); return ret; } @@ -688,16 +703,20 @@ SYSCALL_DEFINE3(inotify_add_watch, int, fd, const char __user *, pathname, struct fsnotify_group *group; struct inode *inode; struct path path; - struct file *filp; - int ret, fput_needed; + struct fd f; + int ret; unsigned flags = 0; - filp = fget_light(fd, &fput_needed); - if (unlikely(!filp)) + /* don't allow invalid bits: we don't want flags set */ + if (unlikely(!(mask & ALL_INOTIFY_BITS))) + return -EINVAL; + + f = fdget(fd); + if (unlikely(!f.file)) return -EBADF; /* verify that this is indeed an inotify instance */ - if (unlikely(filp->f_op != &inotify_fops)) { + if (unlikely(f.file->f_op != &inotify_fops)) { ret = -EINVAL; goto fput_and_out; } @@ -713,62 +732,80 @@ SYSCALL_DEFINE3(inotify_add_watch, int, fd, const char __user *, pathname, /* inode held in place by reference to path; group by fget on fd */ inode = path.dentry->d_inode; - group = filp->private_data; + group = f.file->private_data; /* create/update an inode mark */ ret = inotify_update_watch(group, inode, mask); path_put(&path); fput_and_out: - fput_light(filp, fput_needed); + fdput(f); return ret; } SYSCALL_DEFINE2(inotify_rm_watch, int, fd, __s32, wd) { struct fsnotify_group *group; - struct fsnotify_mark_entry *entry; - struct file *filp; - int ret = 0, fput_needed; + struct inotify_inode_mark *i_mark; + struct fd f; + int ret = 0; - filp = fget_light(fd, &fput_needed); - if (unlikely(!filp)) + f = fdget(fd); + if (unlikely(!f.file)) return -EBADF; /* verify that this is indeed an inotify instance */ - if (unlikely(filp->f_op != &inotify_fops)) { - ret = -EINVAL; + ret = -EINVAL; + if (unlikely(f.file->f_op != &inotify_fops)) goto out; - } - group = filp->private_data; + group = f.file->private_data; - spin_lock(&group->inotify_data.idr_lock); - entry = idr_find(&group->inotify_data.idr, wd); - if (unlikely(!entry)) { - spin_unlock(&group->inotify_data.idr_lock); - ret = -EINVAL; + ret = -EINVAL; + i_mark = inotify_idr_find(group, wd); + if (unlikely(!i_mark)) goto out; - } - fsnotify_get_mark(entry); - spin_unlock(&group->inotify_data.idr_lock); - fsnotify_destroy_mark_by_entry(entry); - fsnotify_put_mark(entry); + ret = 0; + + fsnotify_destroy_mark(&i_mark->fsn_mark, group); + + /* match ref taken by inotify_idr_find */ + fsnotify_put_mark(&i_mark->fsn_mark); out: - fput_light(filp, fput_needed); + fdput(f); return ret; } /* - * inotify_user_setup - Our initialization function. Note that we cannnot return + * inotify_user_setup - Our initialization function. Note that we cannot return * error because we have compiled-in VFS hooks. So an (unlikely) failure here * must result in panic(). */ static int __init inotify_user_setup(void) { - inotify_inode_mark_cachep = KMEM_CACHE(inotify_inode_mark_entry, SLAB_PANIC); - event_priv_cachep = KMEM_CACHE(inotify_event_private_data, SLAB_PANIC); + BUILD_BUG_ON(IN_ACCESS != FS_ACCESS); + BUILD_BUG_ON(IN_MODIFY != FS_MODIFY); + BUILD_BUG_ON(IN_ATTRIB != FS_ATTRIB); + BUILD_BUG_ON(IN_CLOSE_WRITE != FS_CLOSE_WRITE); + BUILD_BUG_ON(IN_CLOSE_NOWRITE != FS_CLOSE_NOWRITE); + BUILD_BUG_ON(IN_OPEN != FS_OPEN); + BUILD_BUG_ON(IN_MOVED_FROM != FS_MOVED_FROM); + BUILD_BUG_ON(IN_MOVED_TO != FS_MOVED_TO); + BUILD_BUG_ON(IN_CREATE != FS_CREATE); + BUILD_BUG_ON(IN_DELETE != FS_DELETE); + BUILD_BUG_ON(IN_DELETE_SELF != FS_DELETE_SELF); + BUILD_BUG_ON(IN_MOVE_SELF != FS_MOVE_SELF); + BUILD_BUG_ON(IN_UNMOUNT != FS_UNMOUNT); + BUILD_BUG_ON(IN_Q_OVERFLOW != FS_Q_OVERFLOW); + BUILD_BUG_ON(IN_IGNORED != FS_IN_IGNORED); + BUILD_BUG_ON(IN_EXCL_UNLINK != FS_EXCL_UNLINK); + BUILD_BUG_ON(IN_ISDIR != FS_ISDIR); + BUILD_BUG_ON(IN_ONESHOT != FS_IN_ONESHOT); + + BUG_ON(hweight32(ALL_INOTIFY_BITS) != 21); + + inotify_inode_mark_cachep = KMEM_CACHE(inotify_inode_mark, SLAB_PANIC); inotify_max_queued_events = 16384; inotify_max_user_instances = 128; diff --git a/fs/notify/mark.c b/fs/notify/mark.c new file mode 100644 index 00000000000..d90deaa08e7 --- /dev/null +++ b/fs/notify/mark.c @@ -0,0 +1,375 @@ +/* + * Copyright (C) 2008 Red Hat, Inc., Eric Paris <eparis@redhat.com> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2, or (at your option) + * any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; see the file COPYING. If not, write to + * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. + */ + +/* + * fsnotify inode mark locking/lifetime/and refcnting + * + * REFCNT: + * The group->recnt and mark->refcnt tell how many "things" in the kernel + * currently are referencing the objects. Both kind of objects typically will + * live inside the kernel with a refcnt of 2, one for its creation and one for + * the reference a group and a mark hold to each other. + * If you are holding the appropriate locks, you can take a reference and the + * object itself is guaranteed to survive until the reference is dropped. + * + * LOCKING: + * There are 3 locks involved with fsnotify inode marks and they MUST be taken + * in order as follows: + * + * group->mark_mutex + * mark->lock + * inode->i_lock + * + * group->mark_mutex protects the marks_list anchored inside a given group and + * each mark is hooked via the g_list. It also protects the groups private + * data (i.e group limits). + + * mark->lock protects the marks attributes like its masks and flags. + * Furthermore it protects the access to a reference of the group that the mark + * is assigned to as well as the access to a reference of the inode/vfsmount + * that is being watched by the mark. + * + * inode->i_lock protects the i_fsnotify_marks list anchored inside a + * given inode and each mark is hooked via the i_list. (and sorta the + * free_i_list) + * + * + * LIFETIME: + * Inode marks survive between when they are added to an inode and when their + * refcnt==0. + * + * The inode mark can be cleared for a number of different reasons including: + * - The inode is unlinked for the last time. (fsnotify_inode_remove) + * - The inode is being evicted from cache. (fsnotify_inode_delete) + * - The fs the inode is on is unmounted. (fsnotify_inode_delete/fsnotify_unmount_inodes) + * - Something explicitly requests that it be removed. (fsnotify_destroy_mark) + * - The fsnotify_group associated with the mark is going away and all such marks + * need to be cleaned up. (fsnotify_clear_marks_by_group) + * + * Worst case we are given an inode and need to clean up all the marks on that + * inode. We take i_lock and walk the i_fsnotify_marks safely. For each + * mark on the list we take a reference (so the mark can't disappear under us). + * We remove that mark form the inode's list of marks and we add this mark to a + * private list anchored on the stack using i_free_list; we walk i_free_list + * and before we destroy the mark we make sure that we dont race with a + * concurrent destroy_group by getting a ref to the marks group and taking the + * groups mutex. + + * Very similarly for freeing by group, except we use free_g_list. + * + * This has the very interesting property of being able to run concurrently with + * any (or all) other directions. + */ + +#include <linux/fs.h> +#include <linux/init.h> +#include <linux/kernel.h> +#include <linux/kthread.h> +#include <linux/module.h> +#include <linux/mutex.h> +#include <linux/slab.h> +#include <linux/spinlock.h> +#include <linux/srcu.h> + +#include <linux/atomic.h> + +#include <linux/fsnotify_backend.h> +#include "fsnotify.h" + +struct srcu_struct fsnotify_mark_srcu; +static DEFINE_SPINLOCK(destroy_lock); +static LIST_HEAD(destroy_list); +static DECLARE_WAIT_QUEUE_HEAD(destroy_waitq); + +void fsnotify_get_mark(struct fsnotify_mark *mark) +{ + atomic_inc(&mark->refcnt); +} + +void fsnotify_put_mark(struct fsnotify_mark *mark) +{ + if (atomic_dec_and_test(&mark->refcnt)) { + if (mark->group) + fsnotify_put_group(mark->group); + mark->free_mark(mark); + } +} + +/* + * Any time a mark is getting freed we end up here. + * The caller had better be holding a reference to this mark so we don't actually + * do the final put under the mark->lock + */ +void fsnotify_destroy_mark_locked(struct fsnotify_mark *mark, + struct fsnotify_group *group) +{ + struct inode *inode = NULL; + + BUG_ON(!mutex_is_locked(&group->mark_mutex)); + + spin_lock(&mark->lock); + + /* something else already called this function on this mark */ + if (!(mark->flags & FSNOTIFY_MARK_FLAG_ALIVE)) { + spin_unlock(&mark->lock); + return; + } + + mark->flags &= ~FSNOTIFY_MARK_FLAG_ALIVE; + + if (mark->flags & FSNOTIFY_MARK_FLAG_INODE) { + inode = mark->i.inode; + fsnotify_destroy_inode_mark(mark); + } else if (mark->flags & FSNOTIFY_MARK_FLAG_VFSMOUNT) + fsnotify_destroy_vfsmount_mark(mark); + else + BUG(); + + list_del_init(&mark->g_list); + + spin_unlock(&mark->lock); + + if (inode && (mark->flags & FSNOTIFY_MARK_FLAG_OBJECT_PINNED)) + iput(inode); + /* release lock temporarily */ + mutex_unlock(&group->mark_mutex); + + spin_lock(&destroy_lock); + list_add(&mark->destroy_list, &destroy_list); + spin_unlock(&destroy_lock); + wake_up(&destroy_waitq); + /* + * We don't necessarily have a ref on mark from caller so the above destroy + * may have actually freed it, unless this group provides a 'freeing_mark' + * function which must be holding a reference. + */ + + /* + * Some groups like to know that marks are being freed. This is a + * callback to the group function to let it know that this mark + * is being freed. + */ + if (group->ops->freeing_mark) + group->ops->freeing_mark(mark, group); + + /* + * __fsnotify_update_child_dentry_flags(inode); + * + * I really want to call that, but we can't, we have no idea if the inode + * still exists the second we drop the mark->lock. + * + * The next time an event arrive to this inode from one of it's children + * __fsnotify_parent will see that the inode doesn't care about it's + * children and will update all of these flags then. So really this + * is just a lazy update (and could be a perf win...) + */ + + atomic_dec(&group->num_marks); + + mutex_lock_nested(&group->mark_mutex, SINGLE_DEPTH_NESTING); +} + +void fsnotify_destroy_mark(struct fsnotify_mark *mark, + struct fsnotify_group *group) +{ + mutex_lock_nested(&group->mark_mutex, SINGLE_DEPTH_NESTING); + fsnotify_destroy_mark_locked(mark, group); + mutex_unlock(&group->mark_mutex); +} + +void fsnotify_set_mark_mask_locked(struct fsnotify_mark *mark, __u32 mask) +{ + assert_spin_locked(&mark->lock); + + mark->mask = mask; + + if (mark->flags & FSNOTIFY_MARK_FLAG_INODE) + fsnotify_set_inode_mark_mask_locked(mark, mask); +} + +void fsnotify_set_mark_ignored_mask_locked(struct fsnotify_mark *mark, __u32 mask) +{ + assert_spin_locked(&mark->lock); + + mark->ignored_mask = mask; +} + +/* + * Attach an initialized mark to a given group and fs object. + * These marks may be used for the fsnotify backend to determine which + * event types should be delivered to which group. + */ +int fsnotify_add_mark_locked(struct fsnotify_mark *mark, + struct fsnotify_group *group, struct inode *inode, + struct vfsmount *mnt, int allow_dups) +{ + int ret = 0; + + BUG_ON(inode && mnt); + BUG_ON(!inode && !mnt); + BUG_ON(!mutex_is_locked(&group->mark_mutex)); + + /* + * LOCKING ORDER!!!! + * group->mark_mutex + * mark->lock + * inode->i_lock + */ + spin_lock(&mark->lock); + mark->flags |= FSNOTIFY_MARK_FLAG_ALIVE; + + fsnotify_get_group(group); + mark->group = group; + list_add(&mark->g_list, &group->marks_list); + atomic_inc(&group->num_marks); + fsnotify_get_mark(mark); /* for i_list and g_list */ + + if (inode) { + ret = fsnotify_add_inode_mark(mark, group, inode, allow_dups); + if (ret) + goto err; + } else if (mnt) { + ret = fsnotify_add_vfsmount_mark(mark, group, mnt, allow_dups); + if (ret) + goto err; + } else { + BUG(); + } + + /* this will pin the object if appropriate */ + fsnotify_set_mark_mask_locked(mark, mark->mask); + spin_unlock(&mark->lock); + + if (inode) + __fsnotify_update_child_dentry_flags(inode); + + return ret; +err: + mark->flags &= ~FSNOTIFY_MARK_FLAG_ALIVE; + list_del_init(&mark->g_list); + fsnotify_put_group(group); + mark->group = NULL; + atomic_dec(&group->num_marks); + + spin_unlock(&mark->lock); + + spin_lock(&destroy_lock); + list_add(&mark->destroy_list, &destroy_list); + spin_unlock(&destroy_lock); + wake_up(&destroy_waitq); + + return ret; +} + +int fsnotify_add_mark(struct fsnotify_mark *mark, struct fsnotify_group *group, + struct inode *inode, struct vfsmount *mnt, int allow_dups) +{ + int ret; + mutex_lock(&group->mark_mutex); + ret = fsnotify_add_mark_locked(mark, group, inode, mnt, allow_dups); + mutex_unlock(&group->mark_mutex); + return ret; +} + +/* + * clear any marks in a group in which mark->flags & flags is true + */ +void fsnotify_clear_marks_by_group_flags(struct fsnotify_group *group, + unsigned int flags) +{ + struct fsnotify_mark *lmark, *mark; + + mutex_lock_nested(&group->mark_mutex, SINGLE_DEPTH_NESTING); + list_for_each_entry_safe(mark, lmark, &group->marks_list, g_list) { + if (mark->flags & flags) { + fsnotify_get_mark(mark); + fsnotify_destroy_mark_locked(mark, group); + fsnotify_put_mark(mark); + } + } + mutex_unlock(&group->mark_mutex); +} + +/* + * Given a group, destroy all of the marks associated with that group. + */ +void fsnotify_clear_marks_by_group(struct fsnotify_group *group) +{ + fsnotify_clear_marks_by_group_flags(group, (unsigned int)-1); +} + +void fsnotify_duplicate_mark(struct fsnotify_mark *new, struct fsnotify_mark *old) +{ + assert_spin_locked(&old->lock); + new->i.inode = old->i.inode; + new->m.mnt = old->m.mnt; + if (old->group) + fsnotify_get_group(old->group); + new->group = old->group; + new->mask = old->mask; + new->free_mark = old->free_mark; +} + +/* + * Nothing fancy, just initialize lists and locks and counters. + */ +void fsnotify_init_mark(struct fsnotify_mark *mark, + void (*free_mark)(struct fsnotify_mark *mark)) +{ + memset(mark, 0, sizeof(*mark)); + spin_lock_init(&mark->lock); + atomic_set(&mark->refcnt, 1); + mark->free_mark = free_mark; +} + +static int fsnotify_mark_destroy(void *ignored) +{ + struct fsnotify_mark *mark, *next; + struct list_head private_destroy_list; + + for (;;) { + spin_lock(&destroy_lock); + /* exchange the list head */ + list_replace_init(&destroy_list, &private_destroy_list); + spin_unlock(&destroy_lock); + + synchronize_srcu(&fsnotify_mark_srcu); + + list_for_each_entry_safe(mark, next, &private_destroy_list, destroy_list) { + list_del_init(&mark->destroy_list); + fsnotify_put_mark(mark); + } + + wait_event_interruptible(destroy_waitq, !list_empty(&destroy_list)); + } + + return 0; +} + +static int __init fsnotify_mark_init(void) +{ + struct task_struct *thread; + + thread = kthread_run(fsnotify_mark_destroy, NULL, + "fsnotify_mark"); + if (IS_ERR(thread)) + panic("unable to start fsnotify mark destruction thread."); + + return 0; +} +device_initcall(fsnotify_mark_init); diff --git a/fs/notify/notification.c b/fs/notify/notification.c index b8bf53b4c10..1e58402171a 100644 --- a/fs/notify/notification.c +++ b/fs/notify/notification.c @@ -18,7 +18,7 @@ /* * Basic idea behind the notification queue: An fsnotify group (like inotify) - * sends the userspace notification about events asyncronously some time after + * sends the userspace notification about events asynchronously some time after * the event happened. When inotify gets an event it will need to add that * event to the group notify queue. Since a single event might need to be on * multiple group's notification queues we can't add the event directly to each @@ -43,20 +43,11 @@ #include <linux/slab.h> #include <linux/spinlock.h> -#include <asm/atomic.h> +#include <linux/atomic.h> #include <linux/fsnotify_backend.h> #include "fsnotify.h" -static struct kmem_cache *fsnotify_event_cachep; -static struct kmem_cache *fsnotify_event_holder_cachep; -/* - * This is a magic event we send when the q is too full. Since it doesn't - * hold real event information we just keep one system wide and use it any time - * it is needed. It's refcnt is set 1 at kernel init time and will never - * get set to 0 so it will never get 'freed' - */ -static struct fsnotify_event q_overflow_event; static atomic_t fsnotify_sync_cookie = ATOMIC_INIT(0); /** @@ -76,196 +67,82 @@ bool fsnotify_notify_queue_is_empty(struct fsnotify_group *group) return list_empty(&group->notification_list) ? true : false; } -void fsnotify_get_event(struct fsnotify_event *event) -{ - atomic_inc(&event->refcnt); -} - -void fsnotify_put_event(struct fsnotify_event *event) +void fsnotify_destroy_event(struct fsnotify_group *group, + struct fsnotify_event *event) { - if (!event) + /* Overflow events are per-group and we don't want to free them */ + if (!event || event->mask == FS_Q_OVERFLOW) return; - if (atomic_dec_and_test(&event->refcnt)) { - if (event->data_type == FSNOTIFY_EVENT_PATH) - path_put(&event->path); - - BUG_ON(!list_empty(&event->private_data_list)); - - kfree(event->file_name); - kmem_cache_free(fsnotify_event_cachep, event); - } -} - -struct fsnotify_event_holder *fsnotify_alloc_event_holder(void) -{ - return kmem_cache_alloc(fsnotify_event_holder_cachep, GFP_KERNEL); -} - -void fsnotify_destroy_event_holder(struct fsnotify_event_holder *holder) -{ - kmem_cache_free(fsnotify_event_holder_cachep, holder); -} - -/* - * Find the private data that the group previously attached to this event when - * the group added the event to the notification queue (fsnotify_add_notify_event) - */ -struct fsnotify_event_private_data *fsnotify_remove_priv_from_event(struct fsnotify_group *group, struct fsnotify_event *event) -{ - struct fsnotify_event_private_data *lpriv; - struct fsnotify_event_private_data *priv = NULL; - - assert_spin_locked(&event->lock); - - list_for_each_entry(lpriv, &event->private_data_list, event_list) { - if (lpriv->group == group) { - priv = lpriv; - list_del(&priv->event_list); - break; - } - } - return priv; -} - -/* - * Check if 2 events contain the same information. We do not compare private data - * but at this moment that isn't a problem for any know fsnotify listeners. - */ -static bool event_compare(struct fsnotify_event *old, struct fsnotify_event *new) -{ - if ((old->mask == new->mask) && - (old->to_tell == new->to_tell) && - (old->data_type == new->data_type) && - (old->name_len == new->name_len)) { - switch (old->data_type) { - case (FSNOTIFY_EVENT_INODE): - /* remember, after old was put on the wait_q we aren't - * allowed to look at the inode any more, only thing - * left to check was if the file_name is the same */ - if (!old->name_len || - !strcmp(old->file_name, new->file_name)) - return true; - break; - case (FSNOTIFY_EVENT_PATH): - if ((old->path.mnt == new->path.mnt) && - (old->path.dentry == new->path.dentry)) - return true; - break; - case (FSNOTIFY_EVENT_NONE): - if (old->mask & FS_Q_OVERFLOW) - return true; - else if (old->mask & FS_IN_IGNORED) - return false; - return false; - }; - } - return false; + group->ops->free_event(event); } /* * Add an event to the group notification queue. The group can later pull this - * event off the queue to deal with. If the event is successfully added to the - * group's notification queue, a reference is taken on event. + * event off the queue to deal with. The function returns 0 if the event was + * added to the queue, 1 if the event was merged with some other queued event, + * 2 if the queue of events has overflown. */ -int fsnotify_add_notify_event(struct fsnotify_group *group, struct fsnotify_event *event, - struct fsnotify_event_private_data *priv) +int fsnotify_add_notify_event(struct fsnotify_group *group, + struct fsnotify_event *event, + int (*merge)(struct list_head *, + struct fsnotify_event *)) { - struct fsnotify_event_holder *holder = NULL; - struct list_head *list = &group->notification_list; - struct fsnotify_event_holder *last_holder; - struct fsnotify_event *last_event; int ret = 0; + struct list_head *list = &group->notification_list; - /* - * There is one fsnotify_event_holder embedded inside each fsnotify_event. - * Check if we expect to be able to use that holder. If not alloc a new - * holder. - * For the overflow event it's possible that something will use the in - * event holder before we get the lock so we may need to jump back and - * alloc a new holder, this can't happen for most events... - */ - if (!list_empty(&event->holder.event_list)) { -alloc_holder: - holder = fsnotify_alloc_event_holder(); - if (!holder) - return -ENOMEM; - } + pr_debug("%s: group=%p event=%p\n", __func__, group, event); mutex_lock(&group->notification_mutex); if (group->q_len >= group->max_events) { - event = &q_overflow_event; - ret = -EOVERFLOW; - /* sorry, no private data on the overflow event */ - priv = NULL; - } - - spin_lock(&event->lock); - - if (list_empty(&event->holder.event_list)) { - if (unlikely(holder)) - fsnotify_destroy_event_holder(holder); - holder = &event->holder; - } else if (unlikely(!holder)) { - /* between the time we checked above and got the lock the in - * event holder was used, go back and get a new one */ - spin_unlock(&event->lock); - mutex_unlock(&group->notification_mutex); - goto alloc_holder; + ret = 2; + /* Queue overflow event only if it isn't already queued */ + if (!list_empty(&group->overflow_event->list)) { + mutex_unlock(&group->notification_mutex); + return ret; + } + event = group->overflow_event; + goto queue; } - if (!list_empty(list)) { - last_holder = list_entry(list->prev, struct fsnotify_event_holder, event_list); - last_event = last_holder->event; - if (event_compare(last_event, event)) { - spin_unlock(&event->lock); + if (!list_empty(list) && merge) { + ret = merge(list, event); + if (ret) { mutex_unlock(&group->notification_mutex); - if (holder != &event->holder) - fsnotify_destroy_event_holder(holder); - return -EEXIST; + return ret; } } +queue: group->q_len++; - holder->event = event; - - fsnotify_get_event(event); - list_add_tail(&holder->event_list, list); - if (priv) - list_add_tail(&priv->event_list, &event->private_data_list); - spin_unlock(&event->lock); + list_add_tail(&event->list, list); mutex_unlock(&group->notification_mutex); wake_up(&group->notification_waitq); + kill_fasync(&group->fsn_fa, SIGIO, POLL_IN); return ret; } /* - * Remove and return the first event from the notification list. There is a - * reference held on this event since it was on the list. It is the responsibility - * of the caller to drop this reference. + * Remove and return the first event from the notification list. It is the + * responsibility of the caller to destroy the obtained event */ struct fsnotify_event *fsnotify_remove_notify_event(struct fsnotify_group *group) { struct fsnotify_event *event; - struct fsnotify_event_holder *holder; BUG_ON(!mutex_is_locked(&group->notification_mutex)); - holder = list_first_entry(&group->notification_list, struct fsnotify_event_holder, event_list); - - event = holder->event; - - spin_lock(&event->lock); - holder->event = NULL; - list_del_init(&holder->event_list); - spin_unlock(&event->lock); - - /* event == holder means we are referenced through the in event holder */ - if (holder != &event->holder) - fsnotify_destroy_event_holder(holder); + pr_debug("%s: group=%p\n", __func__, group); + event = list_first_entry(&group->notification_list, + struct fsnotify_event, list); + /* + * We need to init list head for the case of overflow event so that + * check in fsnotify_add_notify_events() works + */ + list_del_init(&event->list); group->q_len--; return event; @@ -276,15 +153,10 @@ struct fsnotify_event *fsnotify_remove_notify_event(struct fsnotify_group *group */ struct fsnotify_event *fsnotify_peek_notify_event(struct fsnotify_group *group) { - struct fsnotify_event *event; - struct fsnotify_event_holder *holder; - BUG_ON(!mutex_is_locked(&group->notification_mutex)); - holder = list_first_entry(&group->notification_list, struct fsnotify_event_holder, event_list); - event = holder->event; - - return event; + return list_first_entry(&group->notification_list, + struct fsnotify_event, list); } /* @@ -294,128 +166,31 @@ struct fsnotify_event *fsnotify_peek_notify_event(struct fsnotify_group *group) void fsnotify_flush_notify(struct fsnotify_group *group) { struct fsnotify_event *event; - struct fsnotify_event_private_data *priv; mutex_lock(&group->notification_mutex); while (!fsnotify_notify_queue_is_empty(group)) { event = fsnotify_remove_notify_event(group); - /* if they don't implement free_event_priv they better not have attached any */ - if (group->ops->free_event_priv) { - spin_lock(&event->lock); - priv = fsnotify_remove_priv_from_event(group, event); - spin_unlock(&event->lock); - if (priv) - group->ops->free_event_priv(priv); - } - fsnotify_put_event(event); /* matches fsnotify_add_notify_event */ + fsnotify_destroy_event(group, event); } mutex_unlock(&group->notification_mutex); } -static void initialize_event(struct fsnotify_event *event) -{ - event->holder.event = NULL; - INIT_LIST_HEAD(&event->holder.event_list); - atomic_set(&event->refcnt, 1); - - spin_lock_init(&event->lock); - - event->path.dentry = NULL; - event->path.mnt = NULL; - event->inode = NULL; - event->data_type = FSNOTIFY_EVENT_NONE; - - INIT_LIST_HEAD(&event->private_data_list); - - event->to_tell = NULL; - - event->file_name = NULL; - event->name_len = 0; - - event->sync_cookie = 0; -} - /* * fsnotify_create_event - Allocate a new event which will be sent to each * group's handle_event function if the group was interested in this * particular event. * - * @to_tell the inode which is supposed to receive the event (sometimes a + * @inode the inode which is supposed to receive the event (sometimes a * parent of the inode to which the event happened. * @mask what actually happened. * @data pointer to the object which was actually affected * @data_type flag indication if the data is a file, path, inode, nothing... * @name the filename, if available */ -struct fsnotify_event *fsnotify_create_event(struct inode *to_tell, __u32 mask, void *data, - int data_type, const char *name, u32 cookie, - gfp_t gfp) +void fsnotify_init_event(struct fsnotify_event *event, struct inode *inode, + u32 mask) { - struct fsnotify_event *event; - - event = kmem_cache_alloc(fsnotify_event_cachep, gfp); - if (!event) - return NULL; - - initialize_event(event); - - if (name) { - event->file_name = kstrdup(name, gfp); - if (!event->file_name) { - kmem_cache_free(fsnotify_event_cachep, event); - return NULL; - } - event->name_len = strlen(event->file_name); - } - - event->sync_cookie = cookie; - event->to_tell = to_tell; - - switch (data_type) { - case FSNOTIFY_EVENT_FILE: { - struct file *file = data; - struct path *path = &file->f_path; - event->path.dentry = path->dentry; - event->path.mnt = path->mnt; - path_get(&event->path); - event->data_type = FSNOTIFY_EVENT_PATH; - break; - } - case FSNOTIFY_EVENT_PATH: { - struct path *path = data; - event->path.dentry = path->dentry; - event->path.mnt = path->mnt; - path_get(&event->path); - event->data_type = FSNOTIFY_EVENT_PATH; - break; - } - case FSNOTIFY_EVENT_INODE: - event->inode = data; - event->data_type = FSNOTIFY_EVENT_INODE; - break; - case FSNOTIFY_EVENT_NONE: - event->inode = NULL; - event->path.dentry = NULL; - event->path.mnt = NULL; - break; - default: - BUG(); - } - + INIT_LIST_HEAD(&event->list); + event->inode = inode; event->mask = mask; - - return event; } - -__init int fsnotify_notification_init(void) -{ - fsnotify_event_cachep = KMEM_CACHE(fsnotify_event, SLAB_PANIC); - fsnotify_event_holder_cachep = KMEM_CACHE(fsnotify_event_holder, SLAB_PANIC); - - initialize_event(&q_overflow_event); - q_overflow_event.mask = FS_Q_OVERFLOW; - - return 0; -} -subsys_initcall(fsnotify_notification_init); - diff --git a/fs/notify/vfsmount_mark.c b/fs/notify/vfsmount_mark.c new file mode 100644 index 00000000000..68ca5a8704b --- /dev/null +++ b/fs/notify/vfsmount_mark.c @@ -0,0 +1,200 @@ +/* + * Copyright (C) 2008 Red Hat, Inc., Eric Paris <eparis@redhat.com> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2, or (at your option) + * any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; see the file COPYING. If not, write to + * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. + */ + +#include <linux/fs.h> +#include <linux/init.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/mount.h> +#include <linux/mutex.h> +#include <linux/spinlock.h> + +#include <linux/atomic.h> + +#include <linux/fsnotify_backend.h> +#include "fsnotify.h" +#include "../mount.h" + +void fsnotify_clear_marks_by_mount(struct vfsmount *mnt) +{ + struct fsnotify_mark *mark, *lmark; + struct hlist_node *n; + struct mount *m = real_mount(mnt); + LIST_HEAD(free_list); + + spin_lock(&mnt->mnt_root->d_lock); + hlist_for_each_entry_safe(mark, n, &m->mnt_fsnotify_marks, m.m_list) { + list_add(&mark->m.free_m_list, &free_list); + hlist_del_init_rcu(&mark->m.m_list); + fsnotify_get_mark(mark); + } + spin_unlock(&mnt->mnt_root->d_lock); + + list_for_each_entry_safe(mark, lmark, &free_list, m.free_m_list) { + struct fsnotify_group *group; + + spin_lock(&mark->lock); + fsnotify_get_group(mark->group); + group = mark->group; + spin_unlock(&mark->lock); + + fsnotify_destroy_mark(mark, group); + fsnotify_put_mark(mark); + fsnotify_put_group(group); + } +} + +void fsnotify_clear_vfsmount_marks_by_group(struct fsnotify_group *group) +{ + fsnotify_clear_marks_by_group_flags(group, FSNOTIFY_MARK_FLAG_VFSMOUNT); +} + +/* + * Recalculate the mask of events relevant to a given vfsmount locked. + */ +static void fsnotify_recalc_vfsmount_mask_locked(struct vfsmount *mnt) +{ + struct mount *m = real_mount(mnt); + struct fsnotify_mark *mark; + __u32 new_mask = 0; + + assert_spin_locked(&mnt->mnt_root->d_lock); + + hlist_for_each_entry(mark, &m->mnt_fsnotify_marks, m.m_list) + new_mask |= mark->mask; + m->mnt_fsnotify_mask = new_mask; +} + +/* + * Recalculate the mnt->mnt_fsnotify_mask, or the mask of all FS_* event types + * any notifier is interested in hearing for this mount point + */ +void fsnotify_recalc_vfsmount_mask(struct vfsmount *mnt) +{ + spin_lock(&mnt->mnt_root->d_lock); + fsnotify_recalc_vfsmount_mask_locked(mnt); + spin_unlock(&mnt->mnt_root->d_lock); +} + +void fsnotify_destroy_vfsmount_mark(struct fsnotify_mark *mark) +{ + struct vfsmount *mnt = mark->m.mnt; + + BUG_ON(!mutex_is_locked(&mark->group->mark_mutex)); + assert_spin_locked(&mark->lock); + + spin_lock(&mnt->mnt_root->d_lock); + + hlist_del_init_rcu(&mark->m.m_list); + mark->m.mnt = NULL; + + fsnotify_recalc_vfsmount_mask_locked(mnt); + + spin_unlock(&mnt->mnt_root->d_lock); +} + +static struct fsnotify_mark *fsnotify_find_vfsmount_mark_locked(struct fsnotify_group *group, + struct vfsmount *mnt) +{ + struct mount *m = real_mount(mnt); + struct fsnotify_mark *mark; + + assert_spin_locked(&mnt->mnt_root->d_lock); + + hlist_for_each_entry(mark, &m->mnt_fsnotify_marks, m.m_list) { + if (mark->group == group) { + fsnotify_get_mark(mark); + return mark; + } + } + return NULL; +} + +/* + * given a group and vfsmount, find the mark associated with that combination. + * if found take a reference to that mark and return it, else return NULL + */ +struct fsnotify_mark *fsnotify_find_vfsmount_mark(struct fsnotify_group *group, + struct vfsmount *mnt) +{ + struct fsnotify_mark *mark; + + spin_lock(&mnt->mnt_root->d_lock); + mark = fsnotify_find_vfsmount_mark_locked(group, mnt); + spin_unlock(&mnt->mnt_root->d_lock); + + return mark; +} + +/* + * Attach an initialized mark to a given group and vfsmount. + * These marks may be used for the fsnotify backend to determine which + * event types should be delivered to which groups. + */ +int fsnotify_add_vfsmount_mark(struct fsnotify_mark *mark, + struct fsnotify_group *group, struct vfsmount *mnt, + int allow_dups) +{ + struct mount *m = real_mount(mnt); + struct fsnotify_mark *lmark, *last = NULL; + int ret = 0; + + mark->flags |= FSNOTIFY_MARK_FLAG_VFSMOUNT; + + BUG_ON(!mutex_is_locked(&group->mark_mutex)); + assert_spin_locked(&mark->lock); + + spin_lock(&mnt->mnt_root->d_lock); + + mark->m.mnt = mnt; + + /* is mark the first mark? */ + if (hlist_empty(&m->mnt_fsnotify_marks)) { + hlist_add_head_rcu(&mark->m.m_list, &m->mnt_fsnotify_marks); + goto out; + } + + /* should mark be in the middle of the current list? */ + hlist_for_each_entry(lmark, &m->mnt_fsnotify_marks, m.m_list) { + last = lmark; + + if ((lmark->group == group) && !allow_dups) { + ret = -EEXIST; + goto out; + } + + if (mark->group->priority < lmark->group->priority) + continue; + + if ((mark->group->priority == lmark->group->priority) && + (mark->group < lmark->group)) + continue; + + hlist_add_before_rcu(&mark->m.m_list, &lmark->m.m_list); + goto out; + } + + BUG_ON(last == NULL); + /* mark should be the last entry. last is the current last entry */ + hlist_add_after_rcu(&last->m.m_list, &mark->m.m_list); +out: + fsnotify_recalc_vfsmount_mask_locked(mnt); + spin_unlock(&mnt->mnt_root->d_lock); + + return ret; +} |