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fsnotify: get rid of fsnotify_nameremove()
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For all callers of fsnotify_{unlink,rmdir}(), we made sure that d_parent
and d_name are stable.  Therefore, fsnotify_{unlink,rmdir}() do not need
the safety measures in fsnotify_nameremove() to stabilize parent and name.
We can now simplify those hooks and get rid of fsnotify_nameremove().

Signed-off-by: Amir Goldstein <[email protected]>
Signed-off-by: Jan Kara <[email protected]>
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amir73il authored and jankara committed Jun 20, 2019
1 parent 4924646 commit 7377f5b
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Showing 3 changed files with 2 additions and 49 deletions.
41 changes: 0 additions & 41 deletions fs/notify/fsnotify.c
Original file line number Diff line number Diff line change
Expand Up @@ -94,47 +94,6 @@ void fsnotify_sb_delete(struct super_block *sb)
fsnotify_clear_marks_by_sb(sb);
}

/*
* fsnotify_nameremove - a filename was removed from a directory
*
* This is mostly called under parent vfs inode lock so name and
* dentry->d_parent should be stable. However there are some corner cases where
* inode lock is not held. So to be on the safe side and be reselient to future
* callers and out of tree users of d_delete(), we do not assume that d_parent
* and d_name are stable and we use dget_parent() and
* take_dentry_name_snapshot() to grab stable references.
*/
void fsnotify_nameremove(struct dentry *dentry, int isdir)
{
struct dentry *parent;
struct name_snapshot name;
__u32 mask = FS_DELETE;

/* d_delete() of pseudo inode? (e.g. __ns_get_path() playing tricks) */
if (IS_ROOT(dentry))
return;

if (isdir)
mask |= FS_ISDIR;

parent = dget_parent(dentry);
/* Avoid unneeded take_dentry_name_snapshot() */
if (!(d_inode(parent)->i_fsnotify_mask & FS_DELETE) &&
!(dentry->d_sb->s_fsnotify_mask & FS_DELETE))
goto out_dput;

take_dentry_name_snapshot(&name, dentry);

fsnotify(d_inode(parent), mask, d_inode(dentry), FSNOTIFY_EVENT_INODE,
&name.name, 0);

release_dentry_name_snapshot(&name);

out_dput:
dput(parent);
}
EXPORT_SYMBOL(fsnotify_nameremove);

/*
* 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
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6 changes: 2 additions & 4 deletions include/linux/fsnotify.h
Original file line number Diff line number Diff line change
Expand Up @@ -198,8 +198,7 @@ static inline void fsnotify_unlink(struct inode *dir, struct dentry *dentry)
/* Expected to be called before d_delete() */
WARN_ON_ONCE(d_is_negative(dentry));

/* TODO: call fsnotify_dirent() */
fsnotify_nameremove(dentry, 0);
fsnotify_dirent(dir, dentry, FS_DELETE);
}

/*
Expand All @@ -222,8 +221,7 @@ static inline void fsnotify_rmdir(struct inode *dir, struct dentry *dentry)
/* Expected to be called before d_delete() */
WARN_ON_ONCE(d_is_negative(dentry));

/* TODO: call fsnotify_dirent() */
fsnotify_nameremove(dentry, 1);
fsnotify_dirent(dir, dentry, FS_DELETE | FS_ISDIR);
}

/*
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4 changes: 0 additions & 4 deletions include/linux/fsnotify_backend.h
Original file line number Diff line number Diff line change
Expand Up @@ -355,7 +355,6 @@ extern int __fsnotify_parent(const struct path *path, struct dentry *dentry, __u
extern void __fsnotify_inode_delete(struct inode *inode);
extern void __fsnotify_vfsmount_delete(struct vfsmount *mnt);
extern void fsnotify_sb_delete(struct super_block *sb);
extern void fsnotify_nameremove(struct dentry *dentry, int isdir);
extern u32 fsnotify_get_cookie(void);

static inline int fsnotify_inode_watches_children(struct inode *inode)
Expand Down Expand Up @@ -525,9 +524,6 @@ static inline void __fsnotify_vfsmount_delete(struct vfsmount *mnt)
static inline void fsnotify_sb_delete(struct super_block *sb)
{}

static inline void fsnotify_nameremove(struct dentry *dentry, int isdir)
{}

static inline void fsnotify_update_flags(struct dentry *dentry)
{}

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