From: Jan Kara <jack@xxxxxxx>
inode_to_wb() is used also for filesystems that don't support cgroup
writeback. For these filesystems inode->i_wb is stable during the
lifetime of the inode (it points to bdi->wb) and there's no need to hold
locks protecting the inode->i_wb dereference. Improve the warning in
inode_to_wb() to not trigger for these filesystems.
Signed-off-by: Jan Kara <jack@xxxxxxx>
Reviewed-by: Andreas Gruenbacher <agruenba@xxxxxxxxxx>
---
include/linux/backing-dev.h | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/include/linux/backing-dev.h b/include/linux/backing-dev.h
index 8e7af9a03b41..b503a9a4fa65 100644
--- a/include/linux/backing-dev.h
+++ b/include/linux/backing-dev.h
@@ -245,10 +245,11 @@ wb_get_create_current(struct backing_dev_info *bdi, gfp_t gfp)
* holding either @inode->i_lock, the i_pages lock, or the
* associated wb's list_lock.
*/
-static inline struct bdi_writeback *inode_to_wb(const struct inode *inode)
+static inline struct bdi_writeback *inode_to_wb(struct inode *inode)
{
#ifdef CONFIG_LOCKDEP
WARN_ON_ONCE(debug_locks &&
+ (inode->i_sb->s_iflags & SB_I_CGROUPWB) &&
(!lockdep_is_held(&inode->i_lock) &&
!lockdep_is_held(&inode->i_mapping->i_pages.xa_lock) &&
!lockdep_is_held(&inode->i_wb->list_lock)));
--
2.48.1
