[PATCH] btrfs: show correct warning if can't read data reloc tree

[PATCH] btrfs: show correct warning if can't read data reloc tree

[Mark Harmstone]

If a filesystem is missing its data reloc tree, we get something like
this in dmesg:

  BTRFS warning (device loop11): failed to read root (objectid=4): -2
  BTRFS error (device loop11): open_ctree failed: -2

objectid is BTRFS_DEV_TREE_OBJECTID, but this should actually be the
value of BTRFS_DATA_RELOC_TREE_OBJECTID.

btrfs_read_roots() prints location.objectid on failure, but this isn't
set when reading the data reloc tree. Set location.objectid to the
correct value on failure, so that the error message makes sense.

Signed-off-by: Mark Harmstone <mark@harmstone.com>
---
 fs/btrfs/disk-io.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index e5535bdc5b0c..f1e58c1d6c38 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -2221,6 +2221,7 @@ static int btrfs_read_roots(struct btrfs_fs_info *fs_info)
 				 BTRFS_DATA_RELOC_TREE_OBJECTID, true);
 	if (IS_ERR(root)) {
 		if (!btrfs_test_opt(fs_info, IGNOREBADROOTS)) {
+			location.objectid = BTRFS_DATA_RELOC_TREE_OBJECTID;
 			ret = PTR_ERR(root);
 			goto out;
 		}
-- 
2.51.2

Re: [PATCH] btrfs: show correct warning if can't read data reloc tree

[Qu Wenruo]

在 2025/12/20 04:45, Mark Harmstone 写道:
> If a filesystem is missing its data reloc tree, we get something like
> this in dmesg:
> 
>    BTRFS warning (device loop11): failed to read root (objectid=4): -2
>    BTRFS error (device loop11): open_ctree failed: -2
> 
> objectid is BTRFS_DEV_TREE_OBJECTID, but this should actually be the
> value of BTRFS_DATA_RELOC_TREE_OBJECTID.
> 
> btrfs_read_roots() prints location.objectid on failure, but this isn't
> set when reading the data reloc tree. Set location.objectid to the
> correct value on failure, so that the error message makes sense.
> 
> Signed-off-by: Mark Harmstone <mark@harmstone.com>

Reviewed-by: Qu Wenruo <wqu@suse.com>

Thanks,
Qu

> ---
>   fs/btrfs/disk-io.c | 1 +
>   1 file changed, 1 insertion(+)
> 
> diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
> index e5535bdc5b0c..f1e58c1d6c38 100644
> --- a/fs/btrfs/disk-io.c
> +++ b/fs/btrfs/disk-io.c
> @@ -2221,6 +2221,7 @@ static int btrfs_read_roots(struct btrfs_fs_info *fs_info)
>   				 BTRFS_DATA_RELOC_TREE_OBJECTID, true);
>   	if (IS_ERR(root)) {
>   		if (!btrfs_test_opt(fs_info, IGNOREBADROOTS)) {
> +			location.objectid = BTRFS_DATA_RELOC_TREE_OBJECTID;
>   			ret = PTR_ERR(root);
>   			goto out;
>   		}

Re: [PATCH] btrfs: show correct warning if can't read data reloc tree

[David Sterba]

On Fri, Dec 19, 2025 at 06:15:28PM +0000, Mark Harmstone wrote:
> If a filesystem is missing its data reloc tree, we get something like
> this in dmesg:
> 
>   BTRFS warning (device loop11): failed to read root (objectid=4): -2
>   BTRFS error (device loop11): open_ctree failed: -2
> 
> objectid is BTRFS_DEV_TREE_OBJECTID, but this should actually be the
> value of BTRFS_DATA_RELOC_TREE_OBJECTID.
> 
> btrfs_read_roots() prints location.objectid on failure, but this isn't
> set when reading the data reloc tree. Set location.objectid to the
> correct value on failure, so that the error message makes sense.
> 
> Signed-off-by: Mark Harmstone <mark@harmstone.com>

Added to for-next, thanks.