| Message ID | 20161222091538.28702-4-jack@suse.cz (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Thu, Dec 22, 2016 at 11:15 AM, Jan Kara <jack@suse.cz> wrote: > Move recalculation of inode / vfsmount notification mask under > group->mark_mutex of the mark which was modified. These are the only > places where mask recalculation happens without mark being protected > from detaching from inode / vfsmount which will cause issues with the > following patches. > What am I missing this time? dnotify_handle_event() dnotify_recalc_inode_mask() fsnotify_recalc_inode_mask() /* not under dnotify_group->mark_mutex */ -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Thu 22-12-16 18:27:11, Amir Goldstein wrote: > On Thu, Dec 22, 2016 at 11:15 AM, Jan Kara <jack@suse.cz> wrote: > > Move recalculation of inode / vfsmount notification mask under > > group->mark_mutex of the mark which was modified. These are the only > > places where mask recalculation happens without mark being protected > > from detaching from inode / vfsmount which will cause issues with the > > following patches. > > > > What am I missing this time? > > dnotify_handle_event() > dnotify_recalc_inode_mask() > fsnotify_recalc_inode_mask() /* not under dnotify_group->mark_mutex */ Dnotify uses mark->lock to protect recalculation of mask which also protects mark from being removed from the list. Honza
On Thu, Dec 22, 2016 at 7:31 PM, Jan Kara <jack@suse.cz> wrote: > On Thu 22-12-16 18:27:11, Amir Goldstein wrote: >> On Thu, Dec 22, 2016 at 11:15 AM, Jan Kara <jack@suse.cz> wrote: >> > Move recalculation of inode / vfsmount notification mask under >> > group->mark_mutex of the mark which was modified. These are the only >> > places where mask recalculation happens without mark being protected >> > from detaching from inode / vfsmount which will cause issues with the >> > following patches. >> > >> >> What am I missing this time? >> >> dnotify_handle_event() >> dnotify_recalc_inode_mask() >> fsnotify_recalc_inode_mask() /* not under dnotify_group->mark_mutex */ > > Dnotify uses mark->lock to protect recalculation of mask which also > protects mark from being removed from the list. > Right. Thanks for clarifying. Reviewed-by: Amir Goldstein <amir73il@gmail.com> -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c index 7ebfca6a1427..8dcec9eecafd 100644 --- a/fs/notify/fanotify/fanotify_user.c +++ b/fs/notify/fanotify/fanotify_user.c @@ -541,6 +541,8 @@ static int fanotify_remove_vfsmount_mark(struct fsnotify_group *group, removed = fanotify_mark_remove_from_mask(fsn_mark, mask, flags, &destroy_mark); + if (removed & real_mount(mnt)->mnt_fsnotify_mask) + fsnotify_recalc_vfsmount_mask(mnt); if (destroy_mark) fsnotify_detach_mark(fsn_mark); mutex_unlock(&group->mark_mutex); @@ -548,9 +550,6 @@ static int fanotify_remove_vfsmount_mark(struct fsnotify_group *group, fsnotify_free_mark(fsn_mark); fsnotify_put_mark(fsn_mark); - if (removed & real_mount(mnt)->mnt_fsnotify_mask) - fsnotify_recalc_vfsmount_mask(mnt); - return 0; } @@ -571,6 +570,8 @@ static int fanotify_remove_inode_mark(struct fsnotify_group *group, removed = fanotify_mark_remove_from_mask(fsn_mark, mask, flags, &destroy_mark); + if (removed & inode->i_fsnotify_mask) + fsnotify_recalc_inode_mask(inode); if (destroy_mark) fsnotify_detach_mark(fsn_mark); mutex_unlock(&group->mark_mutex); @@ -579,8 +580,6 @@ static int fanotify_remove_inode_mark(struct fsnotify_group *group, /* matches the fsnotify_find_inode_mark() */ fsnotify_put_mark(fsn_mark); - if (removed & inode->i_fsnotify_mask) - fsnotify_recalc_inode_mask(inode); return 0; } @@ -656,10 +655,9 @@ static int fanotify_add_vfsmount_mark(struct fsnotify_group *group, } } added = fanotify_mark_add_to_mask(fsn_mark, mask, flags); - mutex_unlock(&group->mark_mutex); - if (added & ~real_mount(mnt)->mnt_fsnotify_mask) fsnotify_recalc_vfsmount_mask(mnt); + mutex_unlock(&group->mark_mutex); fsnotify_put_mark(fsn_mark); return 0; @@ -694,10 +692,9 @@ static int fanotify_add_inode_mark(struct fsnotify_group *group, } } added = fanotify_mark_add_to_mask(fsn_mark, mask, flags); - mutex_unlock(&group->mark_mutex); - if (added & ~inode->i_fsnotify_mask) fsnotify_recalc_inode_mask(inode); + mutex_unlock(&group->mark_mutex); fsnotify_put_mark(fsn_mark); return 0;
Move recalculation of inode / vfsmount notification mask under group->mark_mutex of the mark which was modified. These are the only places where mask recalculation happens without mark being protected from detaching from inode / vfsmount which will cause issues with the following patches. Signed-off-by: Jan Kara <jack@suse.cz> --- fs/notify/fanotify/fanotify_user.c | 15 ++++++--------- 1 file changed, 6 insertions(+), 9 deletions(-)