On Sun 30-11-14 00:37:38, Lino Sanfilippo wrote:
> Before flag FAN_ONDIR was implicitly set in a marks ignored mask. This led to
> some inconsistent behaviour:
>
> 1. It was not possible to remove the flag from the ignored mask, once it was
> set
> (implicitly) with a call like
>
> fanotify_mark(fd, FAN_MARK_ADD, FAN_OPEN, AT_FDCWD, "dir");
>
> This was since the needed flag FAN_MARK_ONDIR was only honored when setting a
> marks mask, but not when removing it. Now FAN_ONDIR is only set when
> explicitly
> passed in the masks parameter. It now is also possible to remove it again:
>
> fanotify_mark(fd, FAN_MARK_ADD, FAN_OPEN | FAN_ONDIR , AT_FDCWD, "dir");
> fanotify_mark(fd, FAN_MARK_REMOVE, FAN_ONDIR , AT_FDCWD, "dir");
>
> 2. Subsequent calls to fanotify_mark for a mark that had FAN_ONDIR already set
> in its mask removed the flag, if it was not specified in the mask parameter
> again. Thus
>
> fanotify_mark(fd, FAN_MARK_ADD, FAN_OPEN | FAN_ONDIR , AT_FDCWD, "dir");
> fanotify_mark(fd, FAN_MARK_ADD, FAN_CLOSE, AT_FDCWD, "dir");
>
> set FAN_ONDIR in the first call on the marks mask but also on the ignored
> mask in the second call. So the first request for DIR events was overwritten.
> Since the flag is now not set implicitly any longer this cant happen any more.
Ugh, I have to say I don't understand the changelog. From the code I
think I understood that instead of always adding FAN_ONDIR to ignore mask
you require FAN_ONDIR to be set in the normal mask. That makes sense to me
but please make the changelog more comprehensible. Also please add a
testcase to LTP fanotify() coverage for FAN_ONDIR behavior so that we can
easily see how userspace visible behavior changed / didn't change. Thanks!
Honza
> Signed-off-by: Lino Sanfilippo <linosanfili...@gmx.de>
> ---
> fs/notify/fanotify/fanotify.c | 2 +-
> fs/notify/fanotify/fanotify_user.c | 24 ++++++++++++++++--------
> 2 files changed, 17 insertions(+), 9 deletions(-)
>
> diff --git a/fs/notify/fanotify/fanotify.c b/fs/notify/fanotify/fanotify.c
> index 30d3add..51ceb81 100644
> --- a/fs/notify/fanotify/fanotify.c
> +++ b/fs/notify/fanotify/fanotify.c
> @@ -140,7 +140,7 @@ static bool fanotify_should_send_event(struct
> fsnotify_mark *inode_mark,
> }
>
> if (S_ISDIR(path->dentry->d_inode->i_mode) &&
> - (marks_ignored_mask & FS_ISDIR))
> + !(marks_mask & FS_ISDIR & ~marks_ignored_mask))
> return false;
>
> if (event_mask & marks_mask & ~marks_ignored_mask)
> diff --git a/fs/notify/fanotify/fanotify_user.c
> b/fs/notify/fanotify/fanotify_user.c
> index 3afd8bb..e62463e 100644
> --- a/fs/notify/fanotify/fanotify_user.c
> +++ b/fs/notify/fanotify/fanotify_user.c
> @@ -493,10 +493,17 @@ static __u32 fanotify_mark_remove_from_mask(struct
> fsnotify_mark *fsn_mark,
>
> spin_lock(&fsn_mark->lock);
> if (!(flags & FAN_MARK_IGNORED_MASK)) {
> + __u32 tmask = fsn_mark->mask & ~mask;
> + if (flags & FAN_MARK_ONDIR)
> + tmask &= ~FAN_ONDIR;
> +
> oldmask = fsn_mark->mask;
> - fsnotify_set_mark_mask_locked(fsn_mark, (oldmask & ~mask));
> + fsnotify_set_mark_mask_locked(fsn_mark, tmask);
> } else {
> __u32 tmask = fsn_mark->ignored_mask & ~mask;
> + if (flags & FAN_MARK_ONDIR)
> + tmask &= ~FAN_ONDIR;
> +
> fsnotify_set_mark_ignored_mask_locked(fsn_mark, tmask);
> }
> new_mask = fsn_mark->mask;
> @@ -573,20 +580,21 @@ static __u32 fanotify_mark_add_to_mask(struct
> fsnotify_mark *fsn_mark,
>
> spin_lock(&fsn_mark->lock);
> if (!(flags & FAN_MARK_IGNORED_MASK)) {
> + __u32 tmask = fsn_mark->mask | mask;
> + if (flags & FAN_MARK_ONDIR)
> + tmask |= FAN_ONDIR;
> +
> oldmask = fsn_mark->mask;
> - fsnotify_set_mark_mask_locked(fsn_mark, (oldmask | mask));
> + fsnotify_set_mark_mask_locked(fsn_mark, tmask);
> } else {
> __u32 tmask = fsn_mark->ignored_mask | mask;
> + if (flags & FAN_MARK_ONDIR)
> + tmask |= FAN_ONDIR;
> +
> fsnotify_set_mark_ignored_mask_locked(fsn_mark, tmask);
> if (flags & FAN_MARK_IGNORED_SURV_MODIFY)
> fsn_mark->flags |=
> FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY;
> }
> -
> - if (!(flags & FAN_MARK_ONDIR)) {
> - __u32 tmask = fsn_mark->ignored_mask | FAN_ONDIR;
> - fsnotify_set_mark_ignored_mask_locked(fsn_mark, tmask);
> - }
> -
> spin_unlock(&fsn_mark->lock);
>
> return mask & ~oldmask;
> --
> 1.9.1
>
--
Jan Kara <j...@suse.cz>
SUSE Labs, CR
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