diff options
Diffstat (limited to 'fs/libfs.c')
| -rw-r--r-- | fs/libfs.c | 359 |
1 files changed, 228 insertions, 131 deletions
diff --git a/fs/libfs.c b/fs/libfs.c index a3accdf528a..88e3e00e2ec 100644 --- a/fs/libfs.c +++ b/fs/libfs.c @@ -3,19 +3,28 @@ * Library for filesystems writers. */ -#include <linux/module.h> +#include <linux/blkdev.h> +#include <linux/export.h> #include <linux/pagemap.h> #include <linux/slab.h> #include <linux/mount.h> #include <linux/vfs.h> #include <linux/quotaops.h> #include <linux/mutex.h> +#include <linux/namei.h> #include <linux/exportfs.h> #include <linux/writeback.h> -#include <linux/buffer_head.h> +#include <linux/buffer_head.h> /* sync_mapping_buffers */ #include <asm/uaccess.h> +#include "internal.h" + +static inline int simple_positive(struct dentry *dentry) +{ + return dentry->d_inode && !d_unhashed(dentry); +} + int simple_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat) { @@ -24,6 +33,7 @@ int simple_getattr(struct vfsmount *mnt, struct dentry *dentry, stat->blocks = inode->i_mapping->nrpages << (PAGE_CACHE_SHIFT - 9); return 0; } +EXPORT_SYMBOL(simple_getattr); int simple_statfs(struct dentry *dentry, struct kstatfs *buf) { @@ -32,59 +42,67 @@ int simple_statfs(struct dentry *dentry, struct kstatfs *buf) buf->f_namelen = NAME_MAX; return 0; } +EXPORT_SYMBOL(simple_statfs); /* * Retaining negative dentries for an in-memory filesystem just wastes * memory and lookup time: arrange for them to be deleted immediately. */ -static int simple_delete_dentry(struct dentry *dentry) +int always_delete_dentry(const struct dentry *dentry) { return 1; } +EXPORT_SYMBOL(always_delete_dentry); + +const struct dentry_operations simple_dentry_operations = { + .d_delete = always_delete_dentry, +}; +EXPORT_SYMBOL(simple_dentry_operations); /* * Lookup the data. This is trivial - if the dentry didn't already * exist, we know it is negative. Set d_op to delete negative dentries. */ -struct dentry *simple_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd) +struct dentry *simple_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags) { - static const struct dentry_operations simple_dentry_operations = { - .d_delete = simple_delete_dentry, - }; - if (dentry->d_name.len > NAME_MAX) return ERR_PTR(-ENAMETOOLONG); - dentry->d_op = &simple_dentry_operations; + if (!dentry->d_sb->s_d_op) + d_set_d_op(dentry, &simple_dentry_operations); d_add(dentry, NULL); return NULL; } +EXPORT_SYMBOL(simple_lookup); int dcache_dir_open(struct inode *inode, struct file *file) { - static struct qstr cursor_name = {.len = 1, .name = "."}; + static struct qstr cursor_name = QSTR_INIT(".", 1); file->private_data = d_alloc(file->f_path.dentry, &cursor_name); return file->private_data ? 0 : -ENOMEM; } +EXPORT_SYMBOL(dcache_dir_open); int dcache_dir_close(struct inode *inode, struct file *file) { dput(file->private_data); return 0; } +EXPORT_SYMBOL(dcache_dir_close); -loff_t dcache_dir_lseek(struct file *file, loff_t offset, int origin) +loff_t dcache_dir_lseek(struct file *file, loff_t offset, int whence) { - mutex_lock(&file->f_path.dentry->d_inode->i_mutex); - switch (origin) { + struct dentry *dentry = file->f_path.dentry; + mutex_lock(&dentry->d_inode->i_mutex); + switch (whence) { case 1: offset += file->f_pos; case 0: if (offset >= 0) break; default: - mutex_unlock(&file->f_path.dentry->d_inode->i_mutex); + mutex_unlock(&dentry->d_inode->i_mutex); return -EINVAL; } if (offset != file->f_pos) { @@ -94,23 +112,27 @@ loff_t dcache_dir_lseek(struct file *file, loff_t offset, int origin) struct dentry *cursor = file->private_data; loff_t n = file->f_pos - 2; - spin_lock(&dcache_lock); + spin_lock(&dentry->d_lock); + /* d_lock not required for cursor */ list_del(&cursor->d_u.d_child); - p = file->f_path.dentry->d_subdirs.next; - while (n && p != &file->f_path.dentry->d_subdirs) { + p = dentry->d_subdirs.next; + while (n && p != &dentry->d_subdirs) { struct dentry *next; next = list_entry(p, struct dentry, d_u.d_child); - if (!d_unhashed(next) && next->d_inode) + spin_lock_nested(&next->d_lock, DENTRY_D_LOCK_NESTED); + if (simple_positive(next)) n--; + spin_unlock(&next->d_lock); p = p->next; } list_add_tail(&cursor->d_u.d_child, p); - spin_unlock(&dcache_lock); + spin_unlock(&dentry->d_lock); } } - mutex_unlock(&file->f_path.dentry->d_inode->i_mutex); + mutex_unlock(&dentry->d_inode->i_mutex); return offset; } +EXPORT_SYMBOL(dcache_dir_lseek); /* Relationship between i_mode and the DT_xxx types */ static inline unsigned char dt_type(struct inode *inode) @@ -124,74 +146,64 @@ static inline unsigned char dt_type(struct inode *inode) * both impossible due to the lock on directory. */ -int dcache_readdir(struct file * filp, void * dirent, filldir_t filldir) +int dcache_readdir(struct file *file, struct dir_context *ctx) { - struct dentry *dentry = filp->f_path.dentry; - struct dentry *cursor = filp->private_data; + struct dentry *dentry = file->f_path.dentry; + struct dentry *cursor = file->private_data; struct list_head *p, *q = &cursor->d_u.d_child; - ino_t ino; - int i = filp->f_pos; - switch (i) { - case 0: - ino = dentry->d_inode->i_ino; - if (filldir(dirent, ".", 1, i, ino, DT_DIR) < 0) - break; - filp->f_pos++; - i++; - /* fallthrough */ - case 1: - ino = parent_ino(dentry); - if (filldir(dirent, "..", 2, i, ino, DT_DIR) < 0) - break; - filp->f_pos++; - i++; - /* fallthrough */ - default: - spin_lock(&dcache_lock); - if (filp->f_pos == 2) - list_move(q, &dentry->d_subdirs); + if (!dir_emit_dots(file, ctx)) + return 0; + spin_lock(&dentry->d_lock); + if (ctx->pos == 2) + list_move(q, &dentry->d_subdirs); + + for (p = q->next; p != &dentry->d_subdirs; p = p->next) { + struct dentry *next = list_entry(p, struct dentry, d_u.d_child); + spin_lock_nested(&next->d_lock, DENTRY_D_LOCK_NESTED); + if (!simple_positive(next)) { + spin_unlock(&next->d_lock); + continue; + } - for (p=q->next; p != &dentry->d_subdirs; p=p->next) { - struct dentry *next; - next = list_entry(p, struct dentry, d_u.d_child); - if (d_unhashed(next) || !next->d_inode) - continue; - - spin_unlock(&dcache_lock); - if (filldir(dirent, next->d_name.name, - next->d_name.len, filp->f_pos, - next->d_inode->i_ino, - dt_type(next->d_inode)) < 0) - return 0; - spin_lock(&dcache_lock); - /* next is still alive */ - list_move(q, p); - p = q; - filp->f_pos++; - } - spin_unlock(&dcache_lock); + spin_unlock(&next->d_lock); + spin_unlock(&dentry->d_lock); + if (!dir_emit(ctx, next->d_name.name, next->d_name.len, + next->d_inode->i_ino, dt_type(next->d_inode))) + return 0; + spin_lock(&dentry->d_lock); + spin_lock_nested(&next->d_lock, DENTRY_D_LOCK_NESTED); + /* next is still alive */ + list_move(q, p); + spin_unlock(&next->d_lock); + p = q; + ctx->pos++; } + spin_unlock(&dentry->d_lock); return 0; } +EXPORT_SYMBOL(dcache_readdir); ssize_t generic_read_dir(struct file *filp, char __user *buf, size_t siz, loff_t *ppos) { return -EISDIR; } +EXPORT_SYMBOL(generic_read_dir); const struct file_operations simple_dir_operations = { .open = dcache_dir_open, .release = dcache_dir_close, .llseek = dcache_dir_lseek, .read = generic_read_dir, - .readdir = dcache_readdir, + .iterate = dcache_readdir, .fsync = noop_fsync, }; +EXPORT_SYMBOL(simple_dir_operations); const struct inode_operations simple_dir_inode_operations = { .lookup = simple_lookup, }; +EXPORT_SYMBOL(simple_dir_inode_operations); static const struct super_operations simple_super_operations = { .statfs = simple_statfs, @@ -202,17 +214,18 @@ static const struct super_operations simple_super_operations = { * will never be mountable) */ struct dentry *mount_pseudo(struct file_system_type *fs_type, char *name, - const struct super_operations *ops, unsigned long magic) + const struct super_operations *ops, + const struct dentry_operations *dops, unsigned long magic) { - struct super_block *s = sget(fs_type, NULL, set_anon_super, NULL); + struct super_block *s; struct dentry *dentry; struct inode *root; - struct qstr d_name = {.name = name, .len = strlen(name)}; + struct qstr d_name = QSTR_INIT(name, strlen(name)); + s = sget(fs_type, NULL, set_anon_super, MS_NOUSER, NULL); if (IS_ERR(s)) return ERR_CAST(s); - s->s_flags = MS_NOUSER; s->s_maxbytes = MAX_LFS_FILESIZE; s->s_blocksize = PAGE_SIZE; s->s_blocksize_bits = PAGE_SHIFT; @@ -230,15 +243,14 @@ struct dentry *mount_pseudo(struct file_system_type *fs_type, char *name, root->i_ino = 1; root->i_mode = S_IFDIR | S_IRUSR | S_IWUSR; root->i_atime = root->i_mtime = root->i_ctime = CURRENT_TIME; - dentry = d_alloc(NULL, &d_name); + dentry = __d_alloc(s, &d_name); if (!dentry) { iput(root); goto Enomem; } - dentry->d_sb = s; - dentry->d_parent = dentry; d_instantiate(dentry, root); s->s_root = dentry; + s->s_d_op = dops; s->s_flags |= MS_ACTIVE; return dget(s->s_root); @@ -246,6 +258,15 @@ Enomem: deactivate_locked_super(s); return ERR_PTR(-ENOMEM); } +EXPORT_SYMBOL(mount_pseudo); + +int simple_open(struct inode *inode, struct file *file) +{ + if (inode->i_private) + file->private_data = inode->i_private; + return 0; +} +EXPORT_SYMBOL(simple_open); int simple_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry) { @@ -258,26 +279,28 @@ int simple_link(struct dentry *old_dentry, struct inode *dir, struct dentry *den d_instantiate(dentry, inode); return 0; } - -static inline int simple_positive(struct dentry *dentry) -{ - return dentry->d_inode && !d_unhashed(dentry); -} +EXPORT_SYMBOL(simple_link); int simple_empty(struct dentry *dentry) { struct dentry *child; int ret = 0; - spin_lock(&dcache_lock); - list_for_each_entry(child, &dentry->d_subdirs, d_u.d_child) - if (simple_positive(child)) + spin_lock(&dentry->d_lock); + list_for_each_entry(child, &dentry->d_subdirs, d_u.d_child) { + spin_lock_nested(&child->d_lock, DENTRY_D_LOCK_NESTED); + if (simple_positive(child)) { + spin_unlock(&child->d_lock); goto out; + } + spin_unlock(&child->d_lock); + } ret = 1; out: - spin_unlock(&dcache_lock); + spin_unlock(&dentry->d_lock); return ret; } +EXPORT_SYMBOL(simple_empty); int simple_unlink(struct inode *dir, struct dentry *dentry) { @@ -288,6 +311,7 @@ int simple_unlink(struct inode *dir, struct dentry *dentry) dput(dentry); return 0; } +EXPORT_SYMBOL(simple_unlink); int simple_rmdir(struct inode *dir, struct dentry *dentry) { @@ -299,6 +323,7 @@ int simple_rmdir(struct inode *dir, struct dentry *dentry) drop_nlink(dir); return 0; } +EXPORT_SYMBOL(simple_rmdir); int simple_rename(struct inode *old_dir, struct dentry *old_dentry, struct inode *new_dir, struct dentry *new_dentry) @@ -311,8 +336,10 @@ int simple_rename(struct inode *old_dir, struct dentry *old_dentry, if (new_dentry->d_inode) { simple_unlink(new_dir, new_dentry); - if (they_are_dirs) + if (they_are_dirs) { + drop_nlink(new_dentry->d_inode); drop_nlink(old_dir); + } } else if (they_are_dirs) { drop_nlink(old_dir); inc_nlink(new_dir); @@ -323,6 +350,7 @@ int simple_rename(struct inode *old_dir, struct dentry *old_dentry, return 0; } +EXPORT_SYMBOL(simple_rename); /** * simple_setattr - setattr for simple filesystem @@ -343,8 +371,6 @@ int simple_setattr(struct dentry *dentry, struct iattr *iattr) struct inode *inode = dentry->d_inode; int error; - WARN_ON_ONCE(inode->i_op->truncate); - error = inode_change_ok(inode, iattr); if (error) return error; @@ -365,6 +391,7 @@ int simple_readpage(struct file *file, struct page *page) unlock_page(page); return 0; } +EXPORT_SYMBOL(simple_readpage); int simple_write_begin(struct file *file, struct address_space *mapping, loff_t pos, unsigned len, unsigned flags, @@ -388,6 +415,7 @@ int simple_write_begin(struct file *file, struct address_space *mapping, } return 0; } +EXPORT_SYMBOL(simple_write_begin); /** * simple_write_end - .write_end helper for non-block-device FSes @@ -439,6 +467,7 @@ int simple_write_end(struct file *file, struct address_space *mapping, return copied; } +EXPORT_SYMBOL(simple_write_end); /* * the inodes created here are not hashed. If you use iunique to generate @@ -471,12 +500,10 @@ int simple_fill_super(struct super_block *s, unsigned long magic, inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; inode->i_op = &simple_dir_inode_operations; inode->i_fop = &simple_dir_operations; - inode->i_nlink = 2; - root = d_alloc_root(inode); - if (!root) { - iput(inode); + set_nlink(inode, 2); + root = d_make_root(inode); + if (!root) return -ENOMEM; - } for (i = 0; !files->name || files->name[0]; i++, files++) { if (!files->name) continue; @@ -491,8 +518,10 @@ int simple_fill_super(struct super_block *s, unsigned long magic, if (!dentry) goto out; inode = new_inode(s); - if (!inode) + if (!inode) { + dput(dentry); goto out; + } inode->i_mode = S_IFREG | files->mode; inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; inode->i_fop = files->ops; @@ -503,9 +532,11 @@ int simple_fill_super(struct super_block *s, unsigned long magic, return 0; out: d_genocide(root); + shrink_dcache_parent(root); dput(root); return -ENOMEM; } +EXPORT_SYMBOL(simple_fill_super); static DEFINE_SPINLOCK(pin_fs_lock); @@ -515,7 +546,7 @@ int simple_pin_fs(struct file_system_type *type, struct vfsmount **mount, int *c spin_lock(&pin_fs_lock); if (unlikely(!*mount)) { spin_unlock(&pin_fs_lock); - mnt = vfs_kern_mount(type, 0, type->name, NULL); + mnt = vfs_kern_mount(type, MS_KERNMOUNT, type->name, NULL); if (IS_ERR(mnt)) return PTR_ERR(mnt); spin_lock(&pin_fs_lock); @@ -528,6 +559,7 @@ int simple_pin_fs(struct file_system_type *type, struct vfsmount **mount, int *c mntput(mnt); return 0; } +EXPORT_SYMBOL(simple_pin_fs); void simple_release_fs(struct vfsmount **mount, int *count) { @@ -539,6 +571,7 @@ void simple_release_fs(struct vfsmount **mount, int *count) spin_unlock(&pin_fs_lock); mntput(mnt); } +EXPORT_SYMBOL(simple_release_fs); /** * simple_read_from_buffer - copy data from the buffer to user space @@ -573,6 +606,7 @@ ssize_t simple_read_from_buffer(void __user *to, size_t count, loff_t *ppos, *ppos = pos + count; return count; } +EXPORT_SYMBOL(simple_read_from_buffer); /** * simple_write_to_buffer - copy data from user space to the buffer @@ -607,6 +641,7 @@ ssize_t simple_write_to_buffer(void *to, size_t available, loff_t *ppos, *ppos = pos + count; return count; } +EXPORT_SYMBOL(simple_write_to_buffer); /** * memory_read_from_buffer - copy data from the buffer @@ -638,6 +673,7 @@ ssize_t memory_read_from_buffer(void *to, size_t count, loff_t *ppos, return count; } +EXPORT_SYMBOL(memory_read_from_buffer); /* * Transaction based IO. @@ -659,6 +695,7 @@ void simple_transaction_set(struct file *file, size_t n) smp_mb(); ar->size = n; } +EXPORT_SYMBOL(simple_transaction_set); char *simple_transaction_get(struct file *file, const char __user *buf, size_t size) { @@ -690,6 +727,7 @@ char *simple_transaction_get(struct file *file, const char __user *buf, size_t s return ar->data; } +EXPORT_SYMBOL(simple_transaction_get); ssize_t simple_transaction_read(struct file *file, char __user *buf, size_t size, loff_t *pos) { @@ -699,12 +737,14 @@ ssize_t simple_transaction_read(struct file *file, char __user *buf, size_t size return 0; return simple_read_from_buffer(buf, size, pos, ar->data, ar->size); } +EXPORT_SYMBOL(simple_transaction_read); int simple_transaction_release(struct inode *inode, struct file *file) { free_page((unsigned long)file->private_data); return 0; } +EXPORT_SYMBOL(simple_transaction_release); /* Simple attribute files */ @@ -740,12 +780,14 @@ int simple_attr_open(struct inode *inode, struct file *file, return nonseekable_open(inode, file); } +EXPORT_SYMBOL_GPL(simple_attr_open); int simple_attr_release(struct inode *inode, struct file *file) { kfree(file->private_data); return 0; } +EXPORT_SYMBOL_GPL(simple_attr_release); /* GPL-only? This? Really? */ /* read from the buffer that is filled with the get function */ ssize_t simple_attr_read(struct file *file, char __user *buf, @@ -781,6 +823,7 @@ out: mutex_unlock(&attr->mutex); return ret; } +EXPORT_SYMBOL_GPL(simple_attr_read); /* interpret the buffer as a number to call the set function with */ ssize_t simple_attr_write(struct file *file, const char __user *buf, @@ -805,7 +848,7 @@ ssize_t simple_attr_write(struct file *file, const char __user *buf, goto out; attr->set_buf[size] = '\0'; - val = simple_strtol(attr->set_buf, NULL, 0); + val = simple_strtoll(attr->set_buf, NULL, 0); ret = attr->set(attr->data, val); if (ret == 0) ret = len; /* on success, claim we got the whole input */ @@ -813,6 +856,7 @@ out: mutex_unlock(&attr->mutex); return ret; } +EXPORT_SYMBOL_GPL(simple_attr_write); /** * generic_fh_to_dentry - generic helper for the fh_to_dentry export operation @@ -847,7 +891,7 @@ struct dentry *generic_fh_to_dentry(struct super_block *sb, struct fid *fid, EXPORT_SYMBOL_GPL(generic_fh_to_dentry); /** - * generic_fh_to_dentry - generic helper for the fh_to_parent export operation + * generic_fh_to_parent - generic helper for the fh_to_parent export operation * @sb: filesystem to do the file handle conversion on * @fid: file handle to convert * @fh_len: length of the file handle in bytes @@ -880,31 +924,66 @@ struct dentry *generic_fh_to_parent(struct super_block *sb, struct fid *fid, EXPORT_SYMBOL_GPL(generic_fh_to_parent); /** - * generic_file_fsync - generic fsync implementation for simple filesystems + * __generic_file_fsync - generic fsync implementation for simple filesystems + * * @file: file to synchronize + * @start: start offset in bytes + * @end: end offset in bytes (inclusive) * @datasync: only synchronize essential metadata if true * * This is a generic implementation of the fsync method for simple * filesystems which track all non-inode metadata in the buffers list * hanging off the address_space structure. */ -int generic_file_fsync(struct file *file, int datasync) +int __generic_file_fsync(struct file *file, loff_t start, loff_t end, + int datasync) { struct inode *inode = file->f_mapping->host; int err; int ret; + err = filemap_write_and_wait_range(inode->i_mapping, start, end); + if (err) + return err; + + mutex_lock(&inode->i_mutex); ret = sync_mapping_buffers(inode->i_mapping); if (!(inode->i_state & I_DIRTY)) - return ret; + goto out; if (datasync && !(inode->i_state & I_DIRTY_DATASYNC)) - return ret; + goto out; err = sync_inode_metadata(inode, 1); if (ret == 0) ret = err; + +out: + mutex_unlock(&inode->i_mutex); return ret; } +EXPORT_SYMBOL(__generic_file_fsync); + +/** + * generic_file_fsync - generic fsync implementation for simple filesystems + * with flush + * @file: file to synchronize + * @start: start offset in bytes + * @end: end offset in bytes (inclusive) + * @datasync: only synchronize essential metadata if true + * + */ + +int generic_file_fsync(struct file *file, loff_t start, loff_t end, + int datasync) +{ + struct inode *inode = file->f_mapping->host; + int err; + + err = __generic_file_fsync(file, start, end, datasync); + if (err) + return err; + return blkdev_issue_flush(inode->i_sb->s_bdev, GFP_KERNEL, NULL); +} EXPORT_SYMBOL(generic_file_fsync); /** @@ -939,42 +1018,60 @@ EXPORT_SYMBOL(generic_check_addressable); /* * No-op implementation of ->fsync for in-memory filesystems. */ -int noop_fsync(struct file *file, int datasync) +int noop_fsync(struct file *file, loff_t start, loff_t end, int datasync) { return 0; } - -EXPORT_SYMBOL(dcache_dir_close); -EXPORT_SYMBOL(dcache_dir_lseek); -EXPORT_SYMBOL(dcache_dir_open); -EXPORT_SYMBOL(dcache_readdir); -EXPORT_SYMBOL(generic_read_dir); -EXPORT_SYMBOL(mount_pseudo); -EXPORT_SYMBOL(simple_write_begin); -EXPORT_SYMBOL(simple_write_end); -EXPORT_SYMBOL(simple_dir_inode_operations); -EXPORT_SYMBOL(simple_dir_operations); -EXPORT_SYMBOL(simple_empty); -EXPORT_SYMBOL(simple_fill_super); -EXPORT_SYMBOL(simple_getattr); -EXPORT_SYMBOL(simple_link); -EXPORT_SYMBOL(simple_lookup); -EXPORT_SYMBOL(simple_pin_fs); -EXPORT_SYMBOL(simple_readpage); -EXPORT_SYMBOL(simple_release_fs); -EXPORT_SYMBOL(simple_rename); -EXPORT_SYMBOL(simple_rmdir); -EXPORT_SYMBOL(simple_statfs); EXPORT_SYMBOL(noop_fsync); -EXPORT_SYMBOL(simple_unlink); -EXPORT_SYMBOL(simple_read_from_buffer); -EXPORT_SYMBOL(simple_write_to_buffer); -EXPORT_SYMBOL(memory_read_from_buffer); -EXPORT_SYMBOL(simple_transaction_set); -EXPORT_SYMBOL(simple_transaction_get); -EXPORT_SYMBOL(simple_transaction_read); -EXPORT_SYMBOL(simple_transaction_release); -EXPORT_SYMBOL_GPL(simple_attr_open); -EXPORT_SYMBOL_GPL(simple_attr_release); -EXPORT_SYMBOL_GPL(simple_attr_read); -EXPORT_SYMBOL_GPL(simple_attr_write); + +void kfree_put_link(struct dentry *dentry, struct nameidata *nd, + void *cookie) +{ + char *s = nd_get_link(nd); + if (!IS_ERR(s)) + kfree(s); +} +EXPORT_SYMBOL(kfree_put_link); + +/* + * nop .set_page_dirty method so that people can use .page_mkwrite on + * anon inodes. + */ +static int anon_set_page_dirty(struct page *page) +{ + return 0; +}; + +/* + * A single inode exists for all anon_inode files. Contrary to pipes, + * anon_inode inodes have no associated per-instance data, so we need + * only allocate one of them. + */ +struct inode *alloc_anon_inode(struct super_block *s) +{ + static const struct address_space_operations anon_aops = { + .set_page_dirty = anon_set_page_dirty, + }; + struct inode *inode = new_inode_pseudo(s); + + if (!inode) + return ERR_PTR(-ENOMEM); + + inode->i_ino = get_next_ino(); + inode->i_mapping->a_ops = &anon_aops; + + /* + * Mark the inode dirty from the very beginning, + * that way it will never be moved to the dirty + * list because mark_inode_dirty() will think + * that it already _is_ on the dirty list. + */ + inode->i_state = I_DIRTY; + inode->i_mode = S_IRUSR | S_IWUSR; + inode->i_uid = current_fsuid(); + inode->i_gid = current_fsgid(); + inode->i_flags |= S_PRIVATE; + inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; + return inode; +} +EXPORT_SYMBOL(alloc_anon_inode); |
