From c757edbef980d4e5d70749d3c98e00279af58b96 Mon Sep 17 00:00:00 2001 From: Johannes Thumshirn Date: Mon, 26 Jan 2026 09:05:24 +0100 Subject: [PATCH] btrfs: fix copying the flags of btrfs_bio after split When a btrfs_bio gets split, only 'bbio->csum_search_commit_root' gets copied to the new btrfs_bio, all the other flags don't. When a bio is split in btrfs_submit_chunk(), btrfs_split_bio() creates the new split bio via btrfs_bio_init() which zeroes the struct with memset. Looking at btrfs_split_bio(), it copies csum_search_commit_root from the original but does not copy can_use_append. After the split, the code does: bbio = split; bio = &bbio->bio; This means the split bio (with can_use_append = false) gets submitted, not the original. In btrfs_submit_dev_bio(), the condition: if (btrfs_bio(bio)->can_use_append && btrfs_dev_is_sequential(...)) Will be false for the split bio even when writing to a sequential zone. Does the split bio need to inherit can_use_append from the original? The old code used a local variable use_append which persisted across the split. Copy the rest of the flags as well. Link: https://lore.kernel.org/linux-btrfs/20260125132120.2525146-1-clm@meta.com/ Reported-by: Chris Mason Reviewed-by: Qu Wenruo Reviewed-by: Boris Burkov Signed-off-by: Johannes Thumshirn Reviewed-by: David Sterba Signed-off-by: David Sterba --- fs/btrfs/bio.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/fs/btrfs/bio.c b/fs/btrfs/bio.c index d3475d1793624..0a69e09bfe28d 100644 --- a/fs/btrfs/bio.c +++ b/fs/btrfs/bio.c @@ -97,7 +97,13 @@ static struct btrfs_bio *btrfs_split_bio(struct btrfs_fs_info *fs_info, bbio->orig_logical = orig_bbio->orig_logical; orig_bbio->orig_logical += map_length; } + bbio->csum_search_commit_root = orig_bbio->csum_search_commit_root; + bbio->can_use_append = orig_bbio->can_use_append; + bbio->is_scrub = orig_bbio->is_scrub; + bbio->is_remap = orig_bbio->is_remap; + bbio->async_csum = orig_bbio->async_csum; + atomic_inc(&orig_bbio->pending_ios); return bbio; } -- 2.47.3