Patch "btrfs: sysfs: fix direct super block member reads" has been added to the 5.15-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    btrfs: sysfs: fix direct super block member reads

to the 5.15-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-sysfs-fix-direct-super-block-member-reads.patch
and it can be found in the queue-5.15 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit af9508b793a97580e29c1734b8bdcef7b4a060bc
Author: Qu Wenruo <wqu@xxxxxxxx>
Date:   Wed Dec 18 17:00:56 2024 +1030

    btrfs: sysfs: fix direct super block member reads
    
    [ Upstream commit fca432e73db2bec0fdbfbf6d98d3ebcd5388a977 ]
    
    The following sysfs entries are reading super block member directly,
    which can have a different endian and cause wrong values:
    
    - sys/fs/btrfs/<uuid>/nodesize
    - sys/fs/btrfs/<uuid>/sectorsize
    - sys/fs/btrfs/<uuid>/clone_alignment
    
    Thankfully those values (nodesize and sectorsize) are always aligned
    inside the btrfs_super_block, so it won't trigger unaligned read errors,
    just endian problems.
    
    Fix them by using the native cached members instead.
    
    Fixes: df93589a1737 ("btrfs: export more from FS_INFO to sysfs")
    CC: stable@xxxxxxxxxxxxxxx
    Reviewed-by: Naohiro Aota <naohiro.aota@xxxxxxx>
    Reviewed-by: Johannes Thumshirn <johannes.thumshirn@xxxxxxx>
    Signed-off-by: Qu Wenruo <wqu@xxxxxxxx>
    Reviewed-by: David Sterba <dsterba@xxxxxxxx>
    Signed-off-by: David Sterba <dsterba@xxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/fs/btrfs/sysfs.c b/fs/btrfs/sysfs.c
index bc8d5b4c279e..6f7f7231e34a 100644
--- a/fs/btrfs/sysfs.c
+++ b/fs/btrfs/sysfs.c
@@ -821,7 +821,7 @@ static ssize_t btrfs_nodesize_show(struct kobject *kobj,
 {
 	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 
-	return sysfs_emit(buf, "%u\n", fs_info->super_copy->nodesize);
+	return sysfs_emit(buf, "%u\n", fs_info->nodesize);
 }
 
 BTRFS_ATTR(, nodesize, btrfs_nodesize_show);
@@ -831,7 +831,7 @@ static ssize_t btrfs_sectorsize_show(struct kobject *kobj,
 {
 	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 
-	return sysfs_emit(buf, "%u\n", fs_info->super_copy->sectorsize);
+	return sysfs_emit(buf, "%u\n", fs_info->sectorsize);
 }
 
 BTRFS_ATTR(, sectorsize, btrfs_sectorsize_show);
@@ -841,7 +841,7 @@ static ssize_t btrfs_clone_alignment_show(struct kobject *kobj,
 {
 	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
 
-	return sysfs_emit(buf, "%u\n", fs_info->super_copy->sectorsize);
+	return sysfs_emit(buf, "%u\n", fs_info->sectorsize);
 }
 
 BTRFS_ATTR(, clone_alignment, btrfs_clone_alignment_show);