linux-kernel - Re: [PATCH v2 3/3] fanotify: dont set FAN_ONDIR implicitly on a marks ignored mask

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Date:	Thu, 4 Dec 2014 13:30:46 +0100
From:	Jan Kara <jack@...e.cz>
To:	Lino Sanfilippo <LinoSanfilippo@....de>
Cc:	eparis@...hat.com, jack@...e.cz, linux-kernel@...r.kernel.org,
	linux-fsdevel@...r.kernel.org
Subject: Re: [PATCH v2 3/3] fanotify: dont set FAN_ONDIR implicitly on a
 marks ignored mask

On Thu 04-12-14 05:43:04, Lino Sanfilippo wrote:
> Currently FAN_ONDIR is always set on a marks ignored mask when the event mask
> is extended without FAN_MARK_ONDIR being set. This may result in events for
> directories being ignored unexpectedly for call sequences like
> 
> fanotify_mark(fd, FAN_MARK_ADD, FAN_OPEN | FAN_ONDIR , AT_FDCWD, "dir");
> fanotify_mark(fd, FAN_MARK_ADD, FAN_CLOSE, AT_FDCWD, "dir");
> 
> Also FAN_MARK_ONDIR is only honored when adding events to a marks mask, but
> not for event removal. Fix both issues.
  Looks good. Changelog is better but please also expand a bit "Fix both
issues" to something like:
Fix both issues by treating FAN_ONDIR as any other event flag and require
FAN_ONDIR to be set on a mark to send events for directories.

Also you can add:
Reviewed-by: Jan Kara <jack@...e.cz>

								Honza
> 
> Signed-off-by: Lino Sanfilippo <LinoSanfilippo@....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 ddc33fb..683d140 100644
> --- a/fs/notify/fanotify/fanotify_user.c
> +++ b/fs/notify/fanotify/fanotify_user.c
> @@ -491,10 +491,17 @@ 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);
>  	}
>  	*destroy = !(fsn_mark->mask | fsn_mark->ignored_mask);
> @@ -568,20 +575,21 @@ 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 <jack@...e.cz>
SUSE Labs, CR
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