writeback: fix false warning in inode_to_wb()

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.

Link: https://lkml.kernel.org/r/20250412163914.3773459-3-agruenba@redhat.com
Fixes: aaa2cacf81 ("writeback: add lockdep annotation to inode_to_wb()")
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Reviewed-by: Andreas Gruenbacher <agruenba@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Andreas Gruenbacher 2025-04-12 18:39:12 +02:00 committed by Andrew Morton
parent fd0ad5e9d1
commit 9e888998ea

View file

@ -249,6 +249,7 @@ static inline struct bdi_writeback *inode_to_wb(const 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)));