From: Teng Liu <27rabbitlt@gmail.com>
Date: Sat, 28 Mar 2026 06:40:59 +0000 (+0100)
Subject: btrfs: replace BUG_ON() with error return in cache_save_setup()
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=30d537f723d6f37a8ddfb17fe668bb9808f5b49f;p=thirdparty%2Fkernel%2Flinux.git

btrfs: replace BUG_ON() with error return in cache_save_setup()

In cache_save_setup(), if create_free_space_inode() succeeds but the
subsequent lookup_free_space_inode() still fails on retry, the
BUG_ON(retries) will crash the kernel. This can happen due to I/O
errors or transient failures, not just programming bugs.

Replace the BUG_ON with proper error handling that returns the original
error code through the existing cleanup path. The callers already handle
this gracefully: disk_cache_state defaults to BTRFS_DC_ERROR, so the
space cache simply won't be written for that block group.

Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Teng Liu <27rabbitlt@gmail.com>
Signed-off-by: David Sterba <dsterba@suse.com>
---

diff --git a/fs/btrfs/block-group.c b/fs/btrfs/block-group.c
index fa6e49a4ba37d..e6f5a17a13e36 100644
--- a/fs/btrfs/block-group.c
+++ b/fs/btrfs/block-group.c
@@ -3381,7 +3381,13 @@ again:
 	}
 
 	if (IS_ERR(inode)) {
-		BUG_ON(retries);
+		if (retries) {
+			ret = PTR_ERR(inode);
+			btrfs_err(fs_info,
+				  "failed to lookup free space inode after creation for block group %llu: %d",
+				  block_group->start, ret);
+			goto out_free;
+		}
 		retries++;
 
 		if (block_group->ro)