+ writeback-fix-false-warning-in-inode_to_wb.patch added to mm-new branch

[Andrew Morton <akpm@linux-foundation.org>]

The patch titled
     Date: Sat, 12 Apr 2025 18:39:12 +0200
has been added to the -mm mm-new branch.  Its filename is
     writeback-fix-false-warning-in-inode_to_wb.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/writeback-fix-false-warning-in-inode_to_wb.patch

This patch will later appear in the mm-new branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------

Subject: writeback: Fix false warning in inode_to_wb()
Date: Sat, 12 Apr 2025 18:39:12 +0200

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
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Reviewed-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 include/linux/backing-dev.h |    1 +
 1 file changed, 1 insertion(+)

--- a/include/linux/backing-dev.h~writeback-fix-false-warning-in-inode_to_wb
+++ a/include/linux/backing-dev.h
@@ -249,6 +249,7 @@ static inline struct bdi_writeback *inod
 {
 #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)));
_

Patches currently in -mm which might be from jack@suse.cz are