diff options
Diffstat (limited to 'fs/autofs4/root.c')
| -rw-r--r-- | fs/autofs4/root.c | 1067 |
1 files changed, 573 insertions, 494 deletions
diff --git a/fs/autofs4/root.c b/fs/autofs4/root.c index 2a771ec6695..cc87c1abac9 100644 --- a/fs/autofs4/root.c +++ b/fs/autofs4/root.c @@ -4,7 +4,7 @@ * * Copyright 1997-1998 Transmeta Corporation -- All Rights Reserved * Copyright 1999-2000 Jeremy Fitzhardinge <jeremy@goop.org> - * Copyright 2001-2003 Ian Kent <raven@themaw.net> + * Copyright 2001-2006 Ian Kent <raven@themaw.net> * * This file is part of the Linux kernel and is made available under * the terms of the GNU General Public License, version 2, or at your @@ -12,41 +12,52 @@ * * ------------------------------------------------------------------------- */ +#include <linux/capability.h> #include <linux/errno.h> #include <linux/stat.h> +#include <linux/slab.h> #include <linux/param.h> #include <linux/time.h> -#include <linux/smp_lock.h> +#include <linux/compat.h> +#include <linux/mutex.h> + #include "autofs_i.h" static int autofs4_dir_symlink(struct inode *,struct dentry *,const char *); static int autofs4_dir_unlink(struct inode *,struct dentry *); static int autofs4_dir_rmdir(struct inode *,struct dentry *); -static int autofs4_dir_mkdir(struct inode *,struct dentry *,int); -static int autofs4_root_ioctl(struct inode *, struct file *,unsigned int,unsigned long); +static int autofs4_dir_mkdir(struct inode *,struct dentry *,umode_t); +static long autofs4_root_ioctl(struct file *,unsigned int,unsigned long); +#ifdef CONFIG_COMPAT +static long autofs4_root_compat_ioctl(struct file *,unsigned int,unsigned long); +#endif static int autofs4_dir_open(struct inode *inode, struct file *file); -static int autofs4_dir_close(struct inode *inode, struct file *file); -static int autofs4_dir_readdir(struct file * filp, void * dirent, filldir_t filldir); -static int autofs4_root_readdir(struct file * filp, void * dirent, filldir_t filldir); -static struct dentry *autofs4_lookup(struct inode *,struct dentry *, struct nameidata *); -static int autofs4_dcache_readdir(struct file *, void *, filldir_t); +static struct dentry *autofs4_lookup(struct inode *,struct dentry *, unsigned int); +static struct vfsmount *autofs4_d_automount(struct path *); +static int autofs4_d_manage(struct dentry *, bool); +static void autofs4_dentry_release(struct dentry *); -struct file_operations autofs4_root_operations = { +const struct file_operations autofs4_root_operations = { .open = dcache_dir_open, .release = dcache_dir_close, .read = generic_read_dir, - .readdir = autofs4_root_readdir, - .ioctl = autofs4_root_ioctl, + .iterate = dcache_readdir, + .llseek = dcache_dir_lseek, + .unlocked_ioctl = autofs4_root_ioctl, +#ifdef CONFIG_COMPAT + .compat_ioctl = autofs4_root_compat_ioctl, +#endif }; -struct file_operations autofs4_dir_operations = { +const struct file_operations autofs4_dir_operations = { .open = autofs4_dir_open, - .release = autofs4_dir_close, + .release = dcache_dir_close, .read = generic_read_dir, - .readdir = autofs4_dir_readdir, + .iterate = dcache_readdir, + .llseek = dcache_dir_lseek, }; -struct inode_operations autofs4_root_inode_operations = { +const struct inode_operations autofs4_dir_inode_operations = { .lookup = autofs4_lookup, .unlink = autofs4_dir_unlink, .symlink = autofs4_dir_symlink, @@ -54,121 +65,48 @@ struct inode_operations autofs4_root_inode_operations = { .rmdir = autofs4_dir_rmdir, }; -struct inode_operations autofs4_dir_inode_operations = { - .lookup = autofs4_lookup, - .unlink = autofs4_dir_unlink, - .symlink = autofs4_dir_symlink, - .mkdir = autofs4_dir_mkdir, - .rmdir = autofs4_dir_rmdir, +const struct dentry_operations autofs4_dentry_operations = { + .d_automount = autofs4_d_automount, + .d_manage = autofs4_d_manage, + .d_release = autofs4_dentry_release, }; -static int autofs4_root_readdir(struct file *file, void *dirent, - filldir_t filldir) +static void autofs4_add_active(struct dentry *dentry) { - struct autofs_sb_info *sbi = autofs4_sbi(file->f_dentry->d_sb); - int oz_mode = autofs4_oz_mode(sbi); - - DPRINTK("called, filp->f_pos = %lld", file->f_pos); - - /* - * Don't set reghost flag if: - * 1) f_pos is larger than zero -- we've already been here. - * 2) we haven't even enabled reghosting in the 1st place. - * 3) this is the daemon doing a readdir - */ - if (oz_mode && file->f_pos == 0 && sbi->reghost_enabled) - sbi->needs_reghost = 1; - - DPRINTK("needs_reghost = %d", sbi->needs_reghost); - - return autofs4_dcache_readdir(file, dirent, filldir); -} - -/* Update usage from here to top of tree, so that scan of - top-level directories will give a useful result */ -static void autofs4_update_usage(struct dentry *dentry) -{ - struct dentry *top = dentry->d_sb->s_root; - - spin_lock(&dcache_lock); - for(; dentry != top; dentry = dentry->d_parent) { - struct autofs_info *ino = autofs4_dentry_ino(dentry); - - if (ino) { - update_atime(dentry->d_inode); - ino->last_used = jiffies; + struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb); + struct autofs_info *ino = autofs4_dentry_ino(dentry); + if (ino) { + spin_lock(&sbi->lookup_lock); + if (!ino->active_count) { + if (list_empty(&ino->active)) + list_add(&ino->active, &sbi->active_list); } + ino->active_count++; + spin_unlock(&sbi->lookup_lock); } - spin_unlock(&dcache_lock); + return; } -/* - * From 2.4 kernel readdir.c - */ -static int autofs4_dcache_readdir(struct file * filp, void * dirent, filldir_t filldir) +static void autofs4_del_active(struct dentry *dentry) { - int i; - struct dentry *dentry = filp->f_dentry; - - i = filp->f_pos; - switch (i) { - case 0: - if (filldir(dirent, ".", 1, i, dentry->d_inode->i_ino, DT_DIR) < 0) - break; - i++; - filp->f_pos++; - /* fallthrough */ - case 1: - if (filldir(dirent, "..", 2, i, dentry->d_parent->d_inode->i_ino, DT_DIR) < 0) - break; - i++; - filp->f_pos++; - /* fallthrough */ - default: { - struct list_head *list; - int j = i-2; - - spin_lock(&dcache_lock); - list = dentry->d_subdirs.next; - - for (;;) { - if (list == &dentry->d_subdirs) { - spin_unlock(&dcache_lock); - return 0; - } - if (!j) - break; - j--; - list = list->next; - } - - while(1) { - struct dentry *de = list_entry(list, struct dentry, d_child); - - if (!d_unhashed(de) && de->d_inode) { - spin_unlock(&dcache_lock); - if (filldir(dirent, de->d_name.name, de->d_name.len, filp->f_pos, de->d_inode->i_ino, DT_UNKNOWN) < 0) - break; - spin_lock(&dcache_lock); - } - filp->f_pos++; - list = list->next; - if (list != &dentry->d_subdirs) - continue; - spin_unlock(&dcache_lock); - break; - } + struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb); + struct autofs_info *ino = autofs4_dentry_ino(dentry); + if (ino) { + spin_lock(&sbi->lookup_lock); + ino->active_count--; + if (!ino->active_count) { + if (!list_empty(&ino->active)) + list_del_init(&ino->active); } + spin_unlock(&sbi->lookup_lock); } - return 0; + return; } static int autofs4_dir_open(struct inode *inode, struct file *file) { - struct dentry *dentry = file->f_dentry; - struct vfsmount *mnt = file->f_vfsmnt; + struct dentry *dentry = file->f_path.dentry; struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb); - int status; DPRINTK("file=%p dentry=%p %.*s", file, dentry, dentry->d_name.len, dentry->d_name.name); @@ -176,348 +114,404 @@ static int autofs4_dir_open(struct inode *inode, struct file *file) if (autofs4_oz_mode(sbi)) goto out; - if (autofs4_ispending(dentry)) { - DPRINTK("dentry busy"); - return -EBUSY; + /* + * An empty directory in an autofs file system is always a + * mount point. The daemon must have failed to mount this + * during lookup so it doesn't exist. This can happen, for + * example, if user space returns an incorrect status for a + * mount request. Otherwise we're doing a readdir on the + * autofs file system so just let the libfs routines handle + * it. + */ + spin_lock(&sbi->lookup_lock); + if (!d_mountpoint(dentry) && simple_empty(dentry)) { + spin_unlock(&sbi->lookup_lock); + return -ENOENT; } + spin_unlock(&sbi->lookup_lock); - if (!d_mountpoint(dentry) && dentry->d_op && dentry->d_op->d_revalidate) { - struct nameidata nd; - int empty; +out: + return dcache_dir_open(inode, file); +} - /* In case there are stale directory dentrys from a failed mount */ - spin_lock(&dcache_lock); - empty = list_empty(&dentry->d_subdirs); - spin_unlock(&dcache_lock); +static void autofs4_dentry_release(struct dentry *de) +{ + struct autofs_info *ino = autofs4_dentry_ino(de); + struct autofs_sb_info *sbi = autofs4_sbi(de->d_sb); - if (!empty) - d_invalidate(dentry); + DPRINTK("releasing %p", de); - nd.flags = LOOKUP_DIRECTORY; - status = (dentry->d_op->d_revalidate)(dentry, &nd); + if (!ino) + return; - if (!status) - return -ENOENT; + if (sbi) { + spin_lock(&sbi->lookup_lock); + if (!list_empty(&ino->active)) + list_del(&ino->active); + if (!list_empty(&ino->expiring)) + list_del(&ino->expiring); + spin_unlock(&sbi->lookup_lock); } - if (d_mountpoint(dentry)) { - struct file *fp = NULL; - struct vfsmount *fp_mnt = mntget(mnt); - struct dentry *fp_dentry = dget(dentry); - - if (!autofs4_follow_mount(&fp_mnt, &fp_dentry)) { - dput(fp_dentry); - mntput(fp_mnt); - return -ENOENT; - } + autofs4_free_ino(ino); +} - fp = dentry_open(fp_dentry, fp_mnt, file->f_flags); - status = PTR_ERR(fp); - if (IS_ERR(fp)) { - file->private_data = NULL; - return status; +static struct dentry *autofs4_lookup_active(struct dentry *dentry) +{ + struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb); + struct dentry *parent = dentry->d_parent; + struct qstr *name = &dentry->d_name; + unsigned int len = name->len; + unsigned int hash = name->hash; + const unsigned char *str = name->name; + struct list_head *p, *head; + + spin_lock(&sbi->lookup_lock); + head = &sbi->active_list; + list_for_each(p, head) { + struct autofs_info *ino; + struct dentry *active; + struct qstr *qstr; + + ino = list_entry(p, struct autofs_info, active); + active = ino->dentry; + + spin_lock(&active->d_lock); + + /* Already gone? */ + if ((int) d_count(active) <= 0) + goto next; + + qstr = &active->d_name; + + if (active->d_name.hash != hash) + goto next; + if (active->d_parent != parent) + goto next; + + if (qstr->len != len) + goto next; + if (memcmp(qstr->name, str, len)) + goto next; + + if (d_unhashed(active)) { + dget_dlock(active); + spin_unlock(&active->d_lock); + spin_unlock(&sbi->lookup_lock); + return active; } - file->private_data = fp; +next: + spin_unlock(&active->d_lock); } -out: - return 0; + spin_unlock(&sbi->lookup_lock); + + return NULL; } -static int autofs4_dir_close(struct inode *inode, struct file *file) +static struct dentry *autofs4_lookup_expiring(struct dentry *dentry) { - struct dentry *dentry = file->f_dentry; struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb); + struct dentry *parent = dentry->d_parent; + struct qstr *name = &dentry->d_name; + unsigned int len = name->len; + unsigned int hash = name->hash; + const unsigned char *str = name->name; + struct list_head *p, *head; + + spin_lock(&sbi->lookup_lock); + head = &sbi->expiring_list; + list_for_each(p, head) { + struct autofs_info *ino; + struct dentry *expiring; + struct qstr *qstr; + + ino = list_entry(p, struct autofs_info, expiring); + expiring = ino->dentry; + + spin_lock(&expiring->d_lock); + + /* We've already been dentry_iput or unlinked */ + if (!expiring->d_inode) + goto next; + + qstr = &expiring->d_name; + + if (expiring->d_name.hash != hash) + goto next; + if (expiring->d_parent != parent) + goto next; + + if (qstr->len != len) + goto next; + if (memcmp(qstr->name, str, len)) + goto next; + + if (d_unhashed(expiring)) { + dget_dlock(expiring); + spin_unlock(&expiring->d_lock); + spin_unlock(&sbi->lookup_lock); + return expiring; + } +next: + spin_unlock(&expiring->d_lock); + } + spin_unlock(&sbi->lookup_lock); - DPRINTK("file=%p dentry=%p %.*s", - file, dentry, dentry->d_name.len, dentry->d_name.name); + return NULL; +} - if (autofs4_oz_mode(sbi)) - goto out; +static int autofs4_mount_wait(struct dentry *dentry) +{ + struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb); + struct autofs_info *ino = autofs4_dentry_ino(dentry); + int status = 0; - if (autofs4_ispending(dentry)) { - DPRINTK("dentry busy"); - return -EBUSY; + if (ino->flags & AUTOFS_INF_PENDING) { + DPRINTK("waiting for mount name=%.*s", + dentry->d_name.len, dentry->d_name.name); + status = autofs4_wait(sbi, dentry, NFY_MOUNT); + DPRINTK("mount wait done status=%d", status); } + ino->last_used = jiffies; + return status; +} - if (d_mountpoint(dentry)) { - struct file *fp = file->private_data; - - if (!fp) - return -ENOENT; +static int do_expire_wait(struct dentry *dentry) +{ + struct dentry *expiring; - filp_close(fp, current->files); - file->private_data = NULL; + expiring = autofs4_lookup_expiring(dentry); + if (!expiring) + return autofs4_expire_wait(dentry); + else { + /* + * If we are racing with expire the request might not + * be quite complete, but the directory has been removed + * so it must have been successful, just wait for it. + */ + autofs4_expire_wait(expiring); + autofs4_del_expiring(expiring); + dput(expiring); } -out: return 0; } -static int autofs4_dir_readdir(struct file *file, void *dirent, filldir_t filldir) +static struct dentry *autofs4_mountpoint_changed(struct path *path) { - struct dentry *dentry = file->f_dentry; + struct dentry *dentry = path->dentry; struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb); - int status; - DPRINTK("file=%p dentry=%p %.*s", - file, dentry, dentry->d_name.len, dentry->d_name.name); - - if (autofs4_oz_mode(sbi)) - goto out; - - if (autofs4_ispending(dentry)) { - DPRINTK("dentry busy"); - return -EBUSY; + /* + * If this is an indirect mount the dentry could have gone away + * as a result of an expire and a new one created. + */ + if (autofs_type_indirect(sbi->type) && d_unhashed(dentry)) { + struct dentry *parent = dentry->d_parent; + struct autofs_info *ino; + struct dentry *new = d_lookup(parent, &dentry->d_name); + if (!new) + return NULL; + ino = autofs4_dentry_ino(new); + ino->last_used = jiffies; + dput(path->dentry); + path->dentry = new; } + return path->dentry; +} - if (d_mountpoint(dentry)) { - struct file *fp = file->private_data; +static struct vfsmount *autofs4_d_automount(struct path *path) +{ + struct dentry *dentry = path->dentry; + struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb); + struct autofs_info *ino = autofs4_dentry_ino(dentry); + int status; - if (!fp) - return -ENOENT; + DPRINTK("dentry=%p %.*s", + dentry, dentry->d_name.len, dentry->d_name.name); - if (!fp->f_op || !fp->f_op->readdir) - goto out; + /* The daemon never triggers a mount. */ + if (autofs4_oz_mode(sbi)) + return NULL; - status = vfs_readdir(fp, filldir, dirent); - file->f_pos = fp->f_pos; + /* + * If an expire request is pending everyone must wait. + * If the expire fails we're still mounted so continue + * the follow and return. A return of -EAGAIN (which only + * happens with indirect mounts) means the expire completed + * and the directory was removed, so just go ahead and try + * the mount. + */ + status = do_expire_wait(dentry); + if (status && status != -EAGAIN) + return NULL; + + /* Callback to the daemon to perform the mount or wait */ + spin_lock(&sbi->fs_lock); + if (ino->flags & AUTOFS_INF_PENDING) { + spin_unlock(&sbi->fs_lock); + status = autofs4_mount_wait(dentry); if (status) - autofs4_copy_atime(file, fp); - return status; + return ERR_PTR(status); + goto done; } -out: - return autofs4_dcache_readdir(file, dirent, filldir); -} -static int try_to_fill_dentry(struct dentry *dentry, - struct super_block *sb, - struct autofs_sb_info *sbi, int flags) -{ - struct autofs_info *de_info = autofs4_dentry_ino(dentry); - int status = 0; + /* + * If the dentry is a symlink it's equivalent to a directory + * having d_mountpoint() true, so there's no need to call back + * to the daemon. + */ + if (dentry->d_inode && S_ISLNK(dentry->d_inode->i_mode)) { + spin_unlock(&sbi->fs_lock); + goto done; + } - /* Block on any pending expiry here; invalidate the dentry - when expiration is done to trigger mount request with a new - dentry */ - if (de_info && (de_info->flags & AUTOFS_INF_EXPIRING)) { - DPRINTK("waiting for expire %p name=%.*s", - dentry, dentry->d_name.len, dentry->d_name.name); - - status = autofs4_wait(sbi, dentry, NFY_NONE); - - DPRINTK("expire done status=%d", status); - + if (!d_mountpoint(dentry)) { /* - * If the directory still exists the mount request must - * continue otherwise it can't be followed at the right - * time during the walk. + * It's possible that user space hasn't removed directories + * after umounting a rootless multi-mount, although it + * should. For v5 have_submounts() is sufficient to handle + * this because the leaves of the directory tree under the + * mount never trigger mounts themselves (they have an autofs + * trigger mount mounted on them). But v4 pseudo direct mounts + * do need the leaves to to trigger mounts. In this case we + * have no choice but to use the list_empty() check and + * require user space behave. */ - status = d_invalidate(dentry); - if (status != -EBUSY) - return 0; - } - - DPRINTK("dentry=%p %.*s ino=%p", - dentry, dentry->d_name.len, dentry->d_name.name, dentry->d_inode); - - /* Wait for a pending mount, triggering one if there isn't one already */ - if (dentry->d_inode == NULL) { - DPRINTK("waiting for mount name=%.*s", - dentry->d_name.len, dentry->d_name.name); - - status = autofs4_wait(sbi, dentry, NFY_MOUNT); - - DPRINTK("mount done status=%d", status); - - if (status && dentry->d_inode) - return 0; /* Try to get the kernel to invalidate this dentry */ - - /* Turn this into a real negative dentry? */ - if (status == -ENOENT) { - dentry->d_time = jiffies + AUTOFS_NEGATIVE_TIMEOUT; - spin_lock(&dentry->d_lock); - dentry->d_flags &= ~DCACHE_AUTOFS_PENDING; - spin_unlock(&dentry->d_lock); - return 1; - } else if (status) { - /* Return a negative dentry, but leave it "pending" */ - return 1; + if (sbi->version > 4) { + if (have_submounts(dentry)) { + spin_unlock(&sbi->fs_lock); + goto done; + } + } else { + if (!simple_empty(dentry)) { + spin_unlock(&sbi->fs_lock); + goto done; + } } - /* Trigger mount for path component or follow link */ - } else if (flags & (LOOKUP_CONTINUE | LOOKUP_DIRECTORY) || - current->link_count) { - DPRINTK("waiting for mount name=%.*s", - dentry->d_name.len, dentry->d_name.name); - - spin_lock(&dentry->d_lock); - dentry->d_flags |= DCACHE_AUTOFS_PENDING; - spin_unlock(&dentry->d_lock); - status = autofs4_wait(sbi, dentry, NFY_MOUNT); - - DPRINTK("mount done status=%d", status); - + ino->flags |= AUTOFS_INF_PENDING; + spin_unlock(&sbi->fs_lock); + status = autofs4_mount_wait(dentry); + spin_lock(&sbi->fs_lock); + ino->flags &= ~AUTOFS_INF_PENDING; if (status) { - spin_lock(&dentry->d_lock); - dentry->d_flags &= ~DCACHE_AUTOFS_PENDING; - spin_unlock(&dentry->d_lock); - return 0; + spin_unlock(&sbi->fs_lock); + return ERR_PTR(status); } } + spin_unlock(&sbi->fs_lock); +done: + /* Mount succeeded, check if we ended up with a new dentry */ + dentry = autofs4_mountpoint_changed(path); + if (!dentry) + return ERR_PTR(-ENOENT); - /* We don't update the usages for the autofs daemon itself, this - is necessary for recursive autofs mounts */ - if (!autofs4_oz_mode(sbi)) - autofs4_update_usage(dentry); - - spin_lock(&dentry->d_lock); - dentry->d_flags &= ~DCACHE_AUTOFS_PENDING; - spin_unlock(&dentry->d_lock); - return 1; + return NULL; } -/* - * Revalidate is called on every cache lookup. Some of those - * cache lookups may actually happen while the dentry is not - * yet completely filled in, and revalidate has to delay such - * lookups.. - */ -static int autofs4_revalidate(struct dentry * dentry, struct nameidata *nd) +static int autofs4_d_manage(struct dentry *dentry, bool rcu_walk) { - struct inode * dir = dentry->d_parent->d_inode; - struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb); - int oz_mode = autofs4_oz_mode(sbi); - int flags = nd ? nd->flags : 0; - int status = 1; - - /* Pending dentry */ - if (autofs4_ispending(dentry)) { - if (!oz_mode) - status = try_to_fill_dentry(dentry, dir->i_sb, sbi, flags); - return status; - } - - /* Negative dentry.. invalidate if "old" */ - if (dentry->d_inode == NULL) - return (dentry->d_time - jiffies <= AUTOFS_NEGATIVE_TIMEOUT); - - /* Check for a non-mountpoint directory with no contents */ - spin_lock(&dcache_lock); - if (S_ISDIR(dentry->d_inode->i_mode) && - !d_mountpoint(dentry) && - list_empty(&dentry->d_subdirs)) { - DPRINTK("dentry=%p %.*s, emptydir", - dentry, dentry->d_name.len, dentry->d_name.name); - spin_unlock(&dcache_lock); - if (!oz_mode) - status = try_to_fill_dentry(dentry, dir->i_sb, sbi, flags); - return status; - } - spin_unlock(&dcache_lock); - - /* Update the usage list */ - if (!oz_mode) - autofs4_update_usage(dentry); + struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb); + struct autofs_info *ino = autofs4_dentry_ino(dentry); + int status; - return 1; -} + DPRINTK("dentry=%p %.*s", + dentry, dentry->d_name.len, dentry->d_name.name); -static void autofs4_dentry_release(struct dentry *de) -{ - struct autofs_info *inf; + /* The daemon never waits. */ + if (autofs4_oz_mode(sbi)) { + if (rcu_walk) + return 0; + if (!d_mountpoint(dentry)) + return -EISDIR; + return 0; + } - DPRINTK("releasing %p", de); + /* We need to sleep, so we need pathwalk to be in ref-mode */ + if (rcu_walk) + return -ECHILD; - inf = autofs4_dentry_ino(de); - de->d_fsdata = NULL; + /* Wait for pending expires */ + do_expire_wait(dentry); - if (inf) { - inf->dentry = NULL; - inf->inode = NULL; + /* + * This dentry may be under construction so wait on mount + * completion. + */ + status = autofs4_mount_wait(dentry); + if (status) + return status; - autofs4_free_ino(inf); + spin_lock(&sbi->fs_lock); + /* + * If the dentry has been selected for expire while we slept + * on the lock then it might go away. We'll deal with that in + * ->d_automount() and wait on a new mount if the expire + * succeeds or return here if it doesn't (since there's no + * mount to follow with a rootless multi-mount). + */ + if (!(ino->flags & AUTOFS_INF_EXPIRING)) { + /* + * Any needed mounting has been completed and the path + * updated so check if this is a rootless multi-mount so + * we can avoid needless calls ->d_automount() and avoid + * an incorrect ELOOP error return. + */ + if ((!d_mountpoint(dentry) && !simple_empty(dentry)) || + (dentry->d_inode && S_ISLNK(dentry->d_inode->i_mode))) + status = -EISDIR; } -} - -/* For dentries of directories in the root dir */ -static struct dentry_operations autofs4_root_dentry_operations = { - .d_revalidate = autofs4_revalidate, - .d_release = autofs4_dentry_release, -}; + spin_unlock(&sbi->fs_lock); -/* For other dentries */ -static struct dentry_operations autofs4_dentry_operations = { - .d_revalidate = autofs4_revalidate, - .d_release = autofs4_dentry_release, -}; + return status; +} /* Lookups in the root directory */ -static struct dentry *autofs4_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd) +static struct dentry *autofs4_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags) { struct autofs_sb_info *sbi; - int oz_mode; + struct autofs_info *ino; + struct dentry *active; - DPRINTK("name = %.*s", - dentry->d_name.len, dentry->d_name.name); + DPRINTK("name = %.*s", dentry->d_name.len, dentry->d_name.name); + /* File name too long to exist */ if (dentry->d_name.len > NAME_MAX) - return ERR_PTR(-ENAMETOOLONG);/* File name too long to exist */ + return ERR_PTR(-ENAMETOOLONG); sbi = autofs4_sbi(dir->i_sb); - oz_mode = autofs4_oz_mode(sbi); DPRINTK("pid = %u, pgrp = %u, catatonic = %d, oz_mode = %d", - current->pid, process_group(current), sbi->catatonic, oz_mode); + current->pid, task_pgrp_nr(current), sbi->catatonic, + autofs4_oz_mode(sbi)); - /* - * Mark the dentry incomplete, but add it. This is needed so - * that the VFS layer knows about the dentry, and we can count - * on catching any lookups through the revalidate. - * - * Let all the hard work be done by the revalidate function that - * needs to be able to do this anyway.. - * - * We need to do this before we release the directory semaphore. - */ - dentry->d_op = &autofs4_root_dentry_operations; + active = autofs4_lookup_active(dentry); + if (active) { + return active; + } else { + /* + * A dentry that is not within the root can never trigger a + * mount operation, unless the directory already exists, so we + * can return fail immediately. The daemon however does need + * to create directories within the file system. + */ + if (!autofs4_oz_mode(sbi) && !IS_ROOT(dentry->d_parent)) + return ERR_PTR(-ENOENT); - if (!oz_mode) { - spin_lock(&dentry->d_lock); - dentry->d_flags |= DCACHE_AUTOFS_PENDING; - spin_unlock(&dentry->d_lock); - } - dentry->d_fsdata = NULL; - d_add(dentry, NULL); + /* Mark entries in the root as mount triggers */ + if (autofs_type_indirect(sbi->type) && IS_ROOT(dentry->d_parent)) + __managed_dentry_set_managed(dentry); - if (dentry->d_op && dentry->d_op->d_revalidate) { - up(&dir->i_sem); - (dentry->d_op->d_revalidate)(dentry, nd); - down(&dir->i_sem); - } + ino = autofs4_new_ino(sbi); + if (!ino) + return ERR_PTR(-ENOMEM); - /* - * If we are still pending, check if we had to handle - * a signal. If so we can force a restart.. - */ - if (dentry->d_flags & DCACHE_AUTOFS_PENDING) { - /* See if we were interrupted */ - if (signal_pending(current)) { - sigset_t *sigset = ¤t->pending.signal; - if (sigismember (sigset, SIGKILL) || - sigismember (sigset, SIGQUIT) || - sigismember (sigset, SIGINT)) { - return ERR_PTR(-ERESTARTNOINTR); - } - } - } + dentry->d_fsdata = ino; + ino->dentry = dentry; - /* - * If this dentry is unhashed, then we shouldn't honour this - * lookup even if the dentry is positive. Returning ENOENT here - * doesn't do the right thing for all system calls, but it should - * be OK for the operations we permit from an autofs. - */ - if ( dentry->d_inode && d_unhashed(dentry) ) - return ERR_PTR(-ENOENT); + autofs4_add_active(dentry); + d_instantiate(dentry, NULL); + } return NULL; } @@ -527,7 +521,9 @@ static int autofs4_dir_symlink(struct inode *dir, { struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb); struct autofs_info *ino = autofs4_dentry_ino(dentry); + struct autofs_info *p_ino; struct inode *inode; + size_t size = strlen(symname); char *cp; DPRINTK("%s <- %.*s", symname, @@ -536,31 +532,34 @@ static int autofs4_dir_symlink(struct inode *dir, if (!autofs4_oz_mode(sbi)) return -EACCES; - ino = autofs4_init_ino(ino, sbi, S_IFLNK | 0555); - if (ino == NULL) - return -ENOSPC; + BUG_ON(!ino); - ino->size = strlen(symname); - ino->u.symlink = cp = kmalloc(ino->size + 1, GFP_KERNEL); + autofs4_clean_ino(ino); - if (cp == NULL) { - kfree(ino); - return -ENOSPC; - } + autofs4_del_active(dentry); - strcpy(cp, symname); + cp = kmalloc(size + 1, GFP_KERNEL); + if (!cp) + return -ENOMEM; - inode = autofs4_get_inode(dir->i_sb, ino); - d_instantiate(dentry, inode); + strcpy(cp, symname); - if (dir == dir->i_sb->s_root->d_inode) - dentry->d_op = &autofs4_root_dentry_operations; - else - dentry->d_op = &autofs4_dentry_operations; + inode = autofs4_get_inode(dir->i_sb, S_IFLNK | 0555); + if (!inode) { + kfree(cp); + if (!dentry->d_fsdata) + kfree(ino); + return -ENOMEM; + } + inode->i_private = cp; + inode->i_size = size; + d_add(dentry, inode); - dentry->d_fsdata = ino; - ino->dentry = dget(dentry); - ino->inode = inode; + dget(dentry); + atomic_inc(&ino->count); + p_ino = autofs4_dentry_ino(dentry->d_parent); + if (p_ino && !IS_ROOT(dentry)) + atomic_inc(&p_ino->count); dir->i_mtime = CURRENT_TIME; @@ -573,9 +572,9 @@ static int autofs4_dir_symlink(struct inode *dir, * Normal filesystems would do a "d_delete()" to tell the VFS dcache * that the file no longer exists. However, doing that means that the * VFS layer can turn the dentry into a negative dentry. We don't want - * this, because since the unlink is probably the result of an expire. - * We simply d_drop it, which allows the dentry lookup to remount it - * if necessary. + * this, because the unlink is probably the result of an expire. + * We simply d_drop it and add it to a expiring list in the super block, + * which allows the dentry lookup to check for an incomplete expire. * * If a process is blocked on the dentry waiting for the expire to finish, * it will invalidate the dentry and try to mount with a new one. @@ -586,97 +585,193 @@ static int autofs4_dir_unlink(struct inode *dir, struct dentry *dentry) { struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb); struct autofs_info *ino = autofs4_dentry_ino(dentry); + struct autofs_info *p_ino; /* This allows root to remove symlinks */ - if ( !autofs4_oz_mode(sbi) && !capable(CAP_SYS_ADMIN) ) - return -EACCES; + if (!autofs4_oz_mode(sbi) && !capable(CAP_SYS_ADMIN)) + return -EPERM; + if (atomic_dec_and_test(&ino->count)) { + p_ino = autofs4_dentry_ino(dentry->d_parent); + if (p_ino && !IS_ROOT(dentry)) + atomic_dec(&p_ino->count); + } dput(ino->dentry); dentry->d_inode->i_size = 0; - dentry->d_inode->i_nlink = 0; + clear_nlink(dentry->d_inode); dir->i_mtime = CURRENT_TIME; + spin_lock(&sbi->lookup_lock); + __autofs4_add_expiring(dentry); d_drop(dentry); + spin_unlock(&sbi->lookup_lock); return 0; } +/* + * Version 4 of autofs provides a pseudo direct mount implementation + * that relies on directories at the leaves of a directory tree under + * an indirect mount to trigger mounts. To allow for this we need to + * set the DMANAGED_AUTOMOUNT and DMANAGED_TRANSIT flags on the leaves + * of the directory tree. There is no need to clear the automount flag + * following a mount or restore it after an expire because these mounts + * are always covered. However, it is necessary to ensure that these + * flags are clear on non-empty directories to avoid unnecessary calls + * during path walks. + */ +static void autofs_set_leaf_automount_flags(struct dentry *dentry) +{ + struct dentry *parent; + + /* root and dentrys in the root are already handled */ + if (IS_ROOT(dentry->d_parent)) + return; + + managed_dentry_set_managed(dentry); + + parent = dentry->d_parent; + /* only consider parents below dentrys in the root */ + if (IS_ROOT(parent->d_parent)) + return; + managed_dentry_clear_managed(parent); + return; +} + +static void autofs_clear_leaf_automount_flags(struct dentry *dentry) +{ + struct list_head *d_child; + struct dentry *parent; + + /* flags for dentrys in the root are handled elsewhere */ + if (IS_ROOT(dentry->d_parent)) + return; + + managed_dentry_clear_managed(dentry); + + parent = dentry->d_parent; + /* only consider parents below dentrys in the root */ + if (IS_ROOT(parent->d_parent)) + return; + d_child = &dentry->d_u.d_child; + /* Set parent managed if it's becoming empty */ + if (d_child->next == &parent->d_subdirs && + d_child->prev == &parent->d_subdirs) + managed_dentry_set_managed(parent); + return; +} + static int autofs4_dir_rmdir(struct inode *dir, struct dentry *dentry) { struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb); struct autofs_info *ino = autofs4_dentry_ino(dentry); + struct autofs_info *p_ino; + DPRINTK("dentry %p, removing %.*s", + dentry, dentry->d_name.len, dentry->d_name.name); + if (!autofs4_oz_mode(sbi)) return -EACCES; - spin_lock(&dcache_lock); - if (!list_empty(&dentry->d_subdirs)) { - spin_unlock(&dcache_lock); + spin_lock(&sbi->lookup_lock); + if (!simple_empty(dentry)) { + spin_unlock(&sbi->lookup_lock); return -ENOTEMPTY; } - spin_lock(&dentry->d_lock); - __d_drop(dentry); - spin_unlock(&dentry->d_lock); - spin_unlock(&dcache_lock); + __autofs4_add_expiring(dentry); + d_drop(dentry); + spin_unlock(&sbi->lookup_lock); - dput(ino->dentry); + if (sbi->version < 5) + autofs_clear_leaf_automount_flags(dentry); + if (atomic_dec_and_test(&ino->count)) { + p_ino = autofs4_dentry_ino(dentry->d_parent); + if (p_ino && dentry->d_parent != dentry) + atomic_dec(&p_ino->count); + } + dput(ino->dentry); dentry->d_inode->i_size = 0; - dentry->d_inode->i_nlink = 0; + clear_nlink(dentry->d_inode); if (dir->i_nlink) - dir->i_nlink--; + drop_nlink(dir); return 0; } -static int autofs4_dir_mkdir(struct inode *dir, struct dentry *dentry, int mode) +static int autofs4_dir_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode) { struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb); struct autofs_info *ino = autofs4_dentry_ino(dentry); + struct autofs_info *p_ino; struct inode *inode; - if ( !autofs4_oz_mode(sbi) ) + if (!autofs4_oz_mode(sbi)) return -EACCES; DPRINTK("dentry %p, creating %.*s", dentry, dentry->d_name.len, dentry->d_name.name); - ino = autofs4_init_ino(ino, sbi, S_IFDIR | 0555); - if (ino == NULL) - return -ENOSPC; + BUG_ON(!ino); - inode = autofs4_get_inode(dir->i_sb, ino); - d_instantiate(dentry, inode); + autofs4_clean_ino(ino); - if (dir == dir->i_sb->s_root->d_inode) - dentry->d_op = &autofs4_root_dentry_operations; - else - dentry->d_op = &autofs4_dentry_operations; + autofs4_del_active(dentry); + + inode = autofs4_get_inode(dir->i_sb, S_IFDIR | 0555); + if (!inode) + return -ENOMEM; + d_add(dentry, inode); + + if (sbi->version < 5) + autofs_set_leaf_automount_flags(dentry); - dentry->d_fsdata = ino; - ino->dentry = dget(dentry); - ino->inode = inode; - dir->i_nlink++; + dget(dentry); + atomic_inc(&ino->count); + p_ino = autofs4_dentry_ino(dentry->d_parent); + if (p_ino && !IS_ROOT(dentry)) + atomic_inc(&p_ino->count); + inc_nlink(dir); dir->i_mtime = CURRENT_TIME; return 0; } /* Get/set timeout ioctl() operation */ +#ifdef CONFIG_COMPAT +static inline int autofs4_compat_get_set_timeout(struct autofs_sb_info *sbi, + compat_ulong_t __user *p) +{ + int rv; + unsigned long ntimeout; + + if ((rv = get_user(ntimeout, p)) || + (rv = put_user(sbi->exp_timeout/HZ, p))) + return rv; + + if (ntimeout > UINT_MAX/HZ) + sbi->exp_timeout = 0; + else + sbi->exp_timeout = ntimeout * HZ; + + return 0; +} +#endif + static inline int autofs4_get_set_timeout(struct autofs_sb_info *sbi, unsigned long __user *p) { int rv; unsigned long ntimeout; - if ( (rv = get_user(ntimeout, p)) || - (rv = put_user(sbi->exp_timeout/HZ, p)) ) + if ((rv = get_user(ntimeout, p)) || + (rv = put_user(sbi->exp_timeout/HZ, p))) return rv; - if ( ntimeout > ULONG_MAX/HZ ) + if (ntimeout > ULONG_MAX/HZ) sbi->exp_timeout = 0; else sbi->exp_timeout = ntimeout * HZ; @@ -697,51 +792,13 @@ static inline int autofs4_get_protosubver(struct autofs_sb_info *sbi, int __user } /* - * Tells the daemon whether we need to reghost or not. Also, clears - * the reghost_needed flag. - */ -static inline int autofs4_ask_reghost(struct autofs_sb_info *sbi, int __user *p) -{ - int status; - - DPRINTK("returning %d", sbi->needs_reghost); - - status = put_user(sbi->needs_reghost, p); - if ( status ) - return status; - - sbi->needs_reghost = 0; - return 0; -} - -/* - * Enable / Disable reghosting ioctl() operation - */ -static inline int autofs4_toggle_reghost(struct autofs_sb_info *sbi, int __user *p) -{ - int status; - int val; - - status = get_user(val, p); - - DPRINTK("reghost = %d", val); - - if (status) - return status; - - /* turn on/off reghosting, with the val */ - sbi->reghost_enabled = val; - return 0; -} - -/* * Tells the daemon whether it can umount the autofs mount. */ static inline int autofs4_ask_umount(struct vfsmount *mnt, int __user *p) { int status = 0; - if (may_umount(mnt) == 0) + if (may_umount(mnt)) status = 1; DPRINTK("returning %d", status); @@ -758,8 +815,7 @@ static inline int autofs4_ask_umount(struct vfsmount *mnt, int __user *p) int is_autofs4_dentry(struct dentry *dentry) { return dentry && dentry->d_inode && - (dentry->d_op == &autofs4_root_dentry_operations || - dentry->d_op == &autofs4_dentry_operations) && + dentry->d_op == &autofs4_dentry_operations && dentry->d_fsdata != NULL; } @@ -767,20 +823,20 @@ int is_autofs4_dentry(struct dentry *dentry) * ioctl()'s on the root directory is the chief method for the daemon to * generate kernel reactions */ -static int autofs4_root_ioctl(struct inode *inode, struct file *filp, - unsigned int cmd, unsigned long arg) +static int autofs4_root_ioctl_unlocked(struct inode *inode, struct file *filp, + unsigned int cmd, unsigned long arg) { struct autofs_sb_info *sbi = autofs4_sbi(inode->i_sb); void __user *p = (void __user *)arg; DPRINTK("cmd = 0x%08x, arg = 0x%08lx, sbi = %p, pgrp = %u", - cmd,arg,sbi,process_group(current)); + cmd,arg,sbi,task_pgrp_nr(current)); - if ( _IOC_TYPE(cmd) != _IOC_TYPE(AUTOFS_IOC_FIRST) || - _IOC_NR(cmd) - _IOC_NR(AUTOFS_IOC_FIRST) >= AUTOFS_IOC_COUNT ) + if (_IOC_TYPE(cmd) != _IOC_TYPE(AUTOFS_IOC_FIRST) || + _IOC_NR(cmd) - _IOC_NR(AUTOFS_IOC_FIRST) >= AUTOFS_IOC_COUNT) return -ENOTTY; - if ( !autofs4_oz_mode(sbi) && !capable(CAP_SYS_ADMIN) ) + if (!autofs4_oz_mode(sbi) && !capable(CAP_SYS_ADMIN)) return -EPERM; switch(cmd) { @@ -797,23 +853,46 @@ static int autofs4_root_ioctl(struct inode *inode, struct file *filp, return autofs4_get_protosubver(sbi, p); case AUTOFS_IOC_SETTIMEOUT: return autofs4_get_set_timeout(sbi, p); - - case AUTOFS_IOC_TOGGLEREGHOST: - return autofs4_toggle_reghost(sbi, p); - case AUTOFS_IOC_ASKREGHOST: - return autofs4_ask_reghost(sbi, p); +#ifdef CONFIG_COMPAT + case AUTOFS_IOC_SETTIMEOUT32: + return autofs4_compat_get_set_timeout(sbi, p); +#endif case AUTOFS_IOC_ASKUMOUNT: - return autofs4_ask_umount(filp->f_vfsmnt, p); + return autofs4_ask_umount(filp->f_path.mnt, p); /* return a single thing to expire */ case AUTOFS_IOC_EXPIRE: - return autofs4_expire_run(inode->i_sb,filp->f_vfsmnt,sbi, p); + return autofs4_expire_run(inode->i_sb,filp->f_path.mnt,sbi, p); /* same as above, but can send multiple expires through pipe */ case AUTOFS_IOC_EXPIRE_MULTI: - return autofs4_expire_multi(inode->i_sb,filp->f_vfsmnt,sbi, p); + return autofs4_expire_multi(inode->i_sb,filp->f_path.mnt,sbi, p); default: return -ENOSYS; } } + +static long autofs4_root_ioctl(struct file *filp, + unsigned int cmd, unsigned long arg) +{ + struct inode *inode = file_inode(filp); + return autofs4_root_ioctl_unlocked(inode, filp, cmd, arg); +} + +#ifdef CONFIG_COMPAT +static long autofs4_root_compat_ioctl(struct file *filp, + unsigned int cmd, unsigned long arg) +{ + struct inode *inode = file_inode(filp); + int ret; + + if (cmd == AUTOFS_IOC_READY || cmd == AUTOFS_IOC_FAIL) + ret = autofs4_root_ioctl_unlocked(inode, filp, cmd, arg); + else + ret = autofs4_root_ioctl_unlocked(inode, filp, cmd, + (unsigned long)compat_ptr(arg)); + + return ret; +} +#endif |