This is a note to let you know that I've just added the patch titled
btrfs: fix spurious free_space_tree remount warning
to the 5.11-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
btrfs-fix-spurious-free_space_tree-remount-warning.patch
and it can be found in the queue-5.11 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From c55a4319c4f2c3ba0a385b1ebc454fa283cfe920 Mon Sep 17 00:00:00 2001
From: Boris Burkov <boris@xxxxxx>
Date: Tue, 23 Feb 2021 10:22:32 -0800
Subject: btrfs: fix spurious free_space_tree remount warning
From: Boris Burkov <boris@xxxxxx>
commit c55a4319c4f2c3ba0a385b1ebc454fa283cfe920 upstream.
The intended logic of the check is to catch cases where the desired
free_space_tree setting doesn't match the mounted setting, and the
remount is anything but ro->rw. However, it makes the mistake of
checking equality on a masked integer (btrfs_test_opt) against a boolean
(btrfs_fs_compat_ro).
If you run the reproducer:
$ mount -o space_cache=v2 dev mnt
$ mount -o remount,ro mnt
you would expect no warning, because the remount is not attempting to
change the free space tree setting, but we do see the warning.
To fix this, add explicit bool type casts to the condition.
I tested a variety of transitions:
sudo mount -o space_cache=v2 /dev/vg0/lv0 mnt/lol
(fst enabled)
mount -o remount,ro mnt/lol
(no warning, no fst change)
sudo mount -o remount,rw,space_cache=v1,clear_cache
(no warning, ro->rw)
sudo mount -o remount,rw,space_cache=v2 mnt
(warning, rw->rw with change)
sudo mount -o remount,ro mnt
(no warning, no fst change)
sudo mount -o remount,rw,space_cache=v2 mnt
(no warning, no fst change)
Reported-by: Chris Murphy <lists@xxxxxxxxxxxxxxxxx>
CC: stable@xxxxxxxxxxxxxxx # 5.11
Signed-off-by: Boris Burkov <boris@xxxxxx>
Reviewed-by: David Sterba <dsterba@xxxxxxxx>
Signed-off-by: David Sterba <dsterba@xxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/btrfs/super.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -1919,8 +1919,8 @@ static int btrfs_remount(struct super_bl
btrfs_resize_thread_pool(fs_info,
fs_info->thread_pool_size, old_thread_pool_size);
- if (btrfs_test_opt(fs_info, FREE_SPACE_TREE) !=
- btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE) &&
+ if ((bool)btrfs_test_opt(fs_info, FREE_SPACE_TREE) !=
+ (bool)btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE) &&
(!sb_rdonly(sb) || (*flags & SB_RDONLY))) {
btrfs_warn(fs_info,
"remount supports changing free space tree only from ro to rw");
Patches currently in stable-queue which might be from boris@xxxxxx are
queue-5.11/btrfs-fix-spurious-free_space_tree-remount-warning.patch
