On Thu 02-07-20 15:57:39, Amir Goldstein wrote:
> MOVE_SELF event does not get reported to a parent watching children
> when a child is moved, but it can be reported to sb/mount mark with
> parent/name info if group is interested in parent/name info.
>
> Use the fsnotify_parent() helper to send a MOVE_SELF event and adjust
> fsnotify() to handle the case of an event "on child" that should not
> be sent to the watching parent's inode mark.
>
> Signed-off-by: Amir Goldstein <amir73il@xxxxxxxxx>
> ---
> fs/notify/fsnotify.c | 21 +++++++++++++++++----
> include/linux/fsnotify.h | 5 +----
> include/linux/fsnotify_backend.h | 2 +-
> 3 files changed, 19 insertions(+), 9 deletions(-)
>
> diff --git a/fs/notify/fsnotify.c b/fs/notify/fsnotify.c
> index 6683c77a5b13..0faf5b09a73e 100644
> --- a/fs/notify/fsnotify.c
> +++ b/fs/notify/fsnotify.c
> @@ -352,6 +352,7 @@ int fsnotify(struct inode *to_tell, __u32 mask, const void *data, int data_type,
> struct super_block *sb = to_tell->i_sb;
> struct inode *dir = S_ISDIR(to_tell->i_mode) ? to_tell : NULL;
> struct mount *mnt = NULL;
> + struct inode *inode = NULL;
> struct inode *child = NULL;
> int ret = 0;
> __u32 test_mask, marks_mask;
> @@ -362,6 +363,14 @@ int fsnotify(struct inode *to_tell, __u32 mask, const void *data, int data_type,
> if (mask & FS_EVENT_ON_CHILD)
> child = fsnotify_data_inode(data, data_type);
>
> + /*
> + * If event is "on child" then to_tell is a watching parent.
> + * An event "on child" may be sent to mount/sb mark with parent/name
> + * info, but not appropriate for watching parent (e.g. FS_MOVE_SELF).
> + */
> + if (!child || (mask & FS_EVENTS_POSS_ON_CHILD))
> + inode = to_tell;
I'm now confused. Don't you want to fill in FSNOTIFY_OBJ_TYPE_INODE below
for FS_MOVE_SELF event? But this condition is false for it so you won't do
it?
> +
> /*
> * Optimization: srcu_read_lock() has a memory barrier which can
> * be expensive. It protects walking the *_fsnotify_marks lists.
> @@ -369,14 +378,17 @@ int fsnotify(struct inode *to_tell, __u32 mask, const void *data, int data_type,
> * SRCU because we have no references to any objects and do not
> * need SRCU to keep them "alive".
> */
> - if (!to_tell->i_fsnotify_marks && !sb->s_fsnotify_marks &&
> + if (!sb->s_fsnotify_marks &&
> (!mnt || !mnt->mnt_fsnotify_marks) &&
> + (!inode || !inode->i_fsnotify_marks) &&
> (!child || !child->i_fsnotify_marks))
> return 0;
>
> - marks_mask = to_tell->i_fsnotify_mask | sb->s_fsnotify_mask;
> + marks_mask = sb->s_fsnotify_mask;
> if (mnt)
> marks_mask |= mnt->mnt_fsnotify_mask;
> + if (inode)
> + marks_mask |= inode->i_fsnotify_mask;
> if (child)
> marks_mask |= child->i_fsnotify_mask;
>
> @@ -390,14 +402,15 @@ int fsnotify(struct inode *to_tell, __u32 mask, const void *data, int data_type,
>
> iter_info.srcu_idx = srcu_read_lock(&fsnotify_mark_srcu);
>
> - iter_info.marks[FSNOTIFY_OBJ_TYPE_INODE] =
> - fsnotify_first_mark(&to_tell->i_fsnotify_marks);
> iter_info.marks[FSNOTIFY_OBJ_TYPE_SB] =
> fsnotify_first_mark(&sb->s_fsnotify_marks);
> if (mnt) {
> iter_info.marks[FSNOTIFY_OBJ_TYPE_VFSMOUNT] =
> fsnotify_first_mark(&mnt->mnt_fsnotify_marks);
> }
> + if (inode)
> + iter_info.marks[FSNOTIFY_OBJ_TYPE_INODE] =
> + fsnotify_first_mark(&inode->i_fsnotify_marks);
> if (child) {
> iter_info.marks[FSNOTIFY_OBJ_TYPE_CHILD] =
> fsnotify_first_mark(&child->i_fsnotify_marks);
> diff --git a/include/linux/fsnotify.h b/include/linux/fsnotify.h
> index 044cae3a0628..61dccaf21e7b 100644
> --- a/include/linux/fsnotify.h
> +++ b/include/linux/fsnotify.h
> @@ -131,7 +131,6 @@ static inline void fsnotify_move(struct inode *old_dir, struct inode *new_dir,
> u32 fs_cookie = fsnotify_get_cookie();
> __u32 old_dir_mask = FS_MOVED_FROM;
> __u32 new_dir_mask = FS_MOVED_TO;
> - __u32 mask = FS_MOVE_SELF;
> const struct qstr *new_name = &moved->d_name;
>
> if (old_dir == new_dir)
> @@ -140,7 +139,6 @@ static inline void fsnotify_move(struct inode *old_dir, struct inode *new_dir,
> if (isdir) {
> old_dir_mask |= FS_ISDIR;
> new_dir_mask |= FS_ISDIR;
> - mask |= FS_ISDIR;
> }
>
> fsnotify_name(old_dir, old_dir_mask, source, old_name, fs_cookie);
> @@ -149,8 +147,7 @@ static inline void fsnotify_move(struct inode *old_dir, struct inode *new_dir,
> if (target)
> fsnotify_link_count(target);
>
> - if (source)
> - fsnotify(source, mask, source, FSNOTIFY_EVENT_INODE, NULL, 0);
> + fsnotify_dentry(moved, FS_MOVE_SELF);
I'm somewhat unsure about this. Does this mean that 'moved' is guaranteed
to be positive or that you've made sure that all the code below
fsnotify_dentry() is actually fine with a negative dentry? I don't find
either trivial to verify so some note in a changelog or maybe even a
separate patch for this would be useful.
Honza
--
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR
