Patch "btrfs: handle bio_split() errors" has been added to the 6.12-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

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

    btrfs: handle bio_split() errors

to the 6.12-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-handle-bio_split-errors.patch
and it can be found in the queue-6.12 subdirectory.

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



commit a1dad7e5e16a042edb28a1b81ece21323d1ae6f5
Author: Johannes Thumshirn <johannes.thumshirn@xxxxxxx>
Date:   Mon Dec 2 23:40:22 2024 -0800

    btrfs: handle bio_split() errors
    
    [ Upstream commit c7c97ceff98cc459bf5e358e5cbd06fcb651d501 ]
    
    Commit e546fe1da9bd ("block: Rework bio_split() return value") changed
    bio_split() so that it can return errors.
    
    Add error handling for it in btrfs_split_bio() and ultimately
    btrfs_submit_chunk(). As the bio is not submitted, the bio counter must
    be decremented to pair btrfs_bio_counter_inc_blocked().
    
    Reviewed-by: John Garry <john.g.garry@xxxxxxxxxx>
    Signed-off-by: Johannes Thumshirn <johannes.thumshirn@xxxxxxx>
    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/bio.c b/fs/btrfs/bio.c
index 31f96c2d8691..5fd0b39d8c70 100644
--- a/fs/btrfs/bio.c
+++ b/fs/btrfs/bio.c
@@ -81,6 +81,9 @@ static struct btrfs_bio *btrfs_split_bio(struct btrfs_fs_info *fs_info,
 
 	bio = bio_split(&orig_bbio->bio, map_length >> SECTOR_SHIFT, GFP_NOFS,
 			&btrfs_clone_bioset);
+	if (IS_ERR(bio))
+		return ERR_CAST(bio);
+
 	bbio = btrfs_bio(bio);
 	btrfs_bio_init(bbio, fs_info, NULL, orig_bbio);
 	bbio->inode = orig_bbio->inode;
@@ -684,7 +687,8 @@ static bool btrfs_submit_chunk(struct btrfs_bio *bbio, int mirror_num)
 				&bioc, &smap, &mirror_num);
 	if (error) {
 		ret = errno_to_blk_status(error);
-		goto fail;
+		btrfs_bio_counter_dec(fs_info);
+		goto end_bbio;
 	}
 
 	map_length = min(map_length, length);
@@ -692,7 +696,15 @@ static bool btrfs_submit_chunk(struct btrfs_bio *bbio, int mirror_num)
 		map_length = btrfs_append_map_length(bbio, map_length);
 
 	if (map_length < length) {
-		bbio = btrfs_split_bio(fs_info, bbio, map_length);
+		struct btrfs_bio *split;
+
+		split = btrfs_split_bio(fs_info, bbio, map_length);
+		if (IS_ERR(split)) {
+			ret = errno_to_blk_status(PTR_ERR(split));
+			btrfs_bio_counter_dec(fs_info);
+			goto end_bbio;
+		}
+		bbio = split;
 		bio = &bbio->bio;
 	}
 
@@ -766,6 +778,7 @@ static bool btrfs_submit_chunk(struct btrfs_bio *bbio, int mirror_num)
 
 		btrfs_bio_end_io(remaining, ret);
 	}
+end_bbio:
 	btrfs_bio_end_io(bbio, ret);
 	/* Do not submit another chunk */
 	return true;