diff options
| author | Amir Goldstein <amir73il@gmail.com> | 2022-04-22 15:03:17 +0300 |
|---|---|---|
| committer | Jan Kara <jack@suse.cz> | 2022-04-25 14:37:22 +0200 |
| commit | 43b245a788e2d8f1bb742668a9bdace02fcb3e96 (patch) | |
| tree | bcd81fb80a6512f99e6b4b15ac59eafe9714fc26 /fs/notify/group.c | |
| parent | f3010343d9e119da35ee864b3a28993bb5c78ed7 (diff) | |
fsnotify: create helpers for group mark_mutex lock
Create helpers to take and release the group mark_mutex lock.
Define a flag FSNOTIFY_GROUP_NOFS in fsnotify_group that determines
if the mark_mutex lock is fs reclaim safe or not. If not safe, the
lock helpers take the lock and disable direct fs reclaim.
In that case we annotate the mutex with a different lockdep class to
express to lockdep that an allocation of mark of an fs reclaim safe group
may take the group lock of another "NOFS" group to evict inodes.
For now, converted only the callers in common code and no backend
defines the NOFS flag. It is intended to be set by fanotify for
evictable marks support.
Link: https://lore.kernel.org/r/20220422120327.3459282-7-amir73il@gmail.com
Suggested-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20220321112310.vpr7oxro2xkz5llh@quack3.lan/
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Diffstat (limited to 'fs/notify/group.c')
| -rw-r--r-- | fs/notify/group.c | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/fs/notify/group.c b/fs/notify/group.c index 18446b7b0d49..1de6631a3925 100644 --- a/fs/notify/group.c +++ b/fs/notify/group.c @@ -115,6 +115,7 @@ static struct fsnotify_group *__fsnotify_alloc_group( const struct fsnotify_ops *ops, int flags, gfp_t gfp) { + static struct lock_class_key nofs_marks_lock; struct fsnotify_group *group; group = kzalloc(sizeof(struct fsnotify_group), gfp); @@ -135,6 +136,16 @@ static struct fsnotify_group *__fsnotify_alloc_group( group->ops = ops; group->flags = flags; + /* + * For most backends, eviction of inode with a mark is not expected, + * because marks hold a refcount on the inode against eviction. + * + * Use a different lockdep class for groups that support evictable + * inode marks, because with evictable marks, mark_mutex is NOT + * fs-reclaim safe - the mutex is taken when evicting inodes. + */ + if (flags & FSNOTIFY_GROUP_NOFS) + lockdep_set_class(&group->mark_mutex, &nofs_marks_lock); return group; } |