diff --git a/fs/dcache.c b/fs/dcache.c
index 05b75fae7ab4396dde161b3e3da4216ad995bd6b..b2ae8fb9eeb9e4c8ee110775f45d5f09bef5b86a 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -3367,3 +3367,30 @@ void __init vfs_caches_init(unsigned long mempages)
bdev_cache_init();
chrdev_init();
}
+
+void take_dentry_name_snapshot(struct name_snapshot *name, struct dentry *dentry)
+{
+ spin_lock(&dentry->d_lock);
+ if (unlikely(dname_external(dentry))) {
+ struct external_name *p = external_name(dentry);
+ atomic_inc(&p->u.count);
+ spin_unlock(&dentry->d_lock);
+ name->name = p->name;
+ } else {
+ memcpy(name->inline_name, dentry->d_iname, DNAME_INLINE_LEN);
+ spin_unlock(&dentry->d_lock);
+ name->name = name->inline_name;
+ }
+}
+EXPORT_SYMBOL(take_dentry_name_snapshot);
+
+void release_dentry_name_snapshot(struct name_snapshot *name)
+{
+ if (unlikely(name->name != name->inline_name)) {
+ struct external_name *p;
+ p = container_of(name->name, struct external_name, name[0]);
+ if (unlikely(atomic_dec_and_test(&p->u.count)))
+ kfree_rcu(p, u.head);
+ }
+}
+EXPORT_SYMBOL(release_dentry_name_snapshot);
diff --git a/fs/debugfs/inode.c b/fs/debugfs/inode.c
index 6f0ce531e2211a42535b0027196f56440b2da63d..1488e13d6221d709fd09c6d72c3b4037e589ff0c 100644
--- a/fs/debugfs/inode.c
+++ b/fs/debugfs/inode.c
@@ -620,7 +620,7 @@ struct dentry *debugfs_rename(struct dentry *old_dir, struct dentry *old_dentry,
{
int error;
struct dentry *dentry = NULL, *trap;
- const char *old_name;
+ struct name_snapshot old_name;
trap = lock_rename(new_dir, old_dir);
/* Source or destination directories don't exist? */
@@ -635,19 +635,19 @@ struct dentry *debugfs_rename(struct dentry *old_dir, struct dentry *old_dentry,
if (IS_ERR(dentry) || dentry == trap || dentry->d_inode)
goto exit;
- old_name = fsnotify_oldname_init(old_dentry->d_name.name);
+ take_dentry_name_snapshot(&old_name, old_dentry);
error = simple_rename(old_dir->d_inode, old_dentry, new_dir->d_inode,
dentry);
if (error) {
- fsnotify_oldname_free(old_name);
+ release_dentry_name_snapshot(&old_name);
goto exit;
}
d_move(old_dentry, dentry);
- fsnotify_move(old_dir->d_inode, new_dir->d_inode, old_name,
+ fsnotify_move(d_inode(old_dir), d_inode(new_dir), old_name.name,
S_ISDIR(old_dentry->d_inode->i_mode),
NULL, old_dentry);
- fsnotify_oldname_free(old_name);
+ release_dentry_name_snapshot(&old_name);
unlock_rename(new_dir, old_dir);
dput(dentry);
return old_dentry;
diff --git a/fs/namei.c b/fs/namei.c
index 5feb2d32ea35e07b15e5d08c76ba83ca1c6e4829..656b36d81d310fd6c65b6fff6a39531d2c884467 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -4177,11 +4177,11 @@ int vfs_rename2(struct vfsmount *mnt,
{
int error;
bool is_dir = d_is_dir(old_dentry);
- const unsigned char *old_name;
struct inode *source = old_dentry->d_inode;
struct inode *target = new_dentry->d_inode;
bool new_is_dir = false;
unsigned max_links = new_dir->i_sb->s_max_links;
+ struct name_snapshot old_name;
if (source == target)
return 0;
@@ -4231,7 +4231,7 @@ int vfs_rename2(struct vfsmount *mnt,
if (error)
return error;
- old_name = fsnotify_oldname_init(old_dentry->d_name.name);
+ take_dentry_name_snapshot(&old_name, old_dentry);
dget(new_dentry);
if (!is_dir || (flags & RENAME_EXCHANGE))
lock_two_nondirectories(source, target);
@@ -4292,14 +4292,14 @@ out:
mutex_unlock(&target->i_mutex);
dput(new_dentry);
if (!error) {
- fsnotify_move(old_dir, new_dir, old_name, is_dir,
+ fsnotify_move(old_dir, new_dir, old_name.name, is_dir,
!(flags & RENAME_EXCHANGE) ? target : NULL, old_dentry);
if (flags & RENAME_EXCHANGE) {
fsnotify_move(new_dir, old_dir, old_dentry->d_name.name,
new_is_dir, NULL, new_dentry);
}
}
- fsnotify_oldname_free(old_name);
+ release_dentry_name_snapshot(&old_name);
return error;
}
diff --git a/fs/notify/fsnotify.c b/fs/notify/fsnotify.c
index 41e39102743a55aa71f41cff96405218c5a4c802..e1f24ede210ec10767e958ab33dbb053ed459b67 100644
--- a/fs/notify/fsnotify.c
+++ b/fs/notify/fsnotify.c
@@ -105,16 +105,20 @@ int __fsnotify_parent(struct path *path, struct dentry *dentry, __u32 mask)
if (unlikely(!fsnotify_inode_watches_children(p_inode)))
__fsnotify_update_child_dentry_flags(p_inode);
else if (p_inode->i_fsnotify_mask & mask) {
+ struct name_snapshot name;
+
/* 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;
+ take_dentry_name_snapshot(&name, dentry);
if (path)
ret = fsnotify(p_inode, mask, path, FSNOTIFY_EVENT_PATH,
- dentry->d_name.name, 0);
+ name.name, 0);
else
ret = fsnotify(p_inode, mask, dentry->d_inode, FSNOTIFY_EVENT_INODE,
- dentry->d_name.name, 0);
+ name.name, 0);
+ release_dentry_name_snapshot(&name);
}
dput(parent);
diff --git a/include/linux/dcache.h b/include/linux/dcache.h
index bac618aa36276c1e19d3ff93c2f5c30dd3a8b58e..331c1d695031854e5398d0dd6d97be77a3cb4a19 100644
--- a/include/linux/dcache.h
+++ b/include/linux/dcache.h
@@ -530,4 +530,11 @@ static inline struct dentry *d_backing_dentry(struct dentry *upper)
return upper;
}
+struct name_snapshot {
+ const char *name;
+ char inline_name[DNAME_INLINE_LEN];
+};
+void take_dentry_name_snapshot(struct name_snapshot *, struct dentry *);
+void release_dentry_name_snapshot(struct name_snapshot *);
+
#endif /* __LINUX_DCACHE_H */
diff --git a/include/linux/fsnotify.h b/include/linux/fsnotify.h
index 7ee1774edee51c7f872a8a9cc5c49fe0e8d83714..a7789559078bbed25b4f7ab2358368513efb1ab2 100644
--- a/include/linux/fsnotify.h
+++ b/include/linux/fsnotify.h
@@ -310,35 +310,4 @@ static inline void fsnotify_change(struct dentry *dentry, unsigned int ia_valid)
}
}
-#if defined(CONFIG_FSNOTIFY) /* notify helpers */
-
-/*
- * fsnotify_oldname_init - save off the old filename before we change it
- */
-static inline const unsigned char *fsnotify_oldname_init(const unsigned char *name)
-{
- return kstrdup(name, GFP_KERNEL);
-}
-
-/*
- * fsnotify_oldname_free - free the name we got from fsnotify_oldname_init
- */
-static inline void fsnotify_oldname_free(const unsigned char *old_name)
-{
- kfree(old_name);
-}
-
-#else /* CONFIG_FSNOTIFY */
-
-static inline const char *fsnotify_oldname_init(const unsigned char *name)
-{
- return NULL;
-}
-
-static inline void fsnotify_oldname_free(const unsigned char *old_name)
-{
-}
-
-#endif /* CONFIG_FSNOTIFY */
-
#endif /* _LINUX_FS_NOTIFY_H */