diff options
| author | Anand Jain <asj@kernel.org> | 2026-04-27 18:18:03 +0800 |
|---|---|---|
| committer | David Sterba <dsterba@suse.com> | 2026-05-26 18:50:42 +0200 |
| commit | 2cd749334ae343446ef6d7e649698c5e40625401 (patch) | |
| tree | f02c4e3a9f3b3c910b786634f9248432ca74242b | |
| parent | 4f756ed83c32ba97506e0fb27fb920e9d66cd9bd (diff) | |
| download | linux-next-history-2cd749334ae343446ef6d7e649698c5e40625401.tar.gz | |
btrfs: use on-disk uuid for s_uuid in temp_fsid mounts
When mounting a cloned filesystem with a temporary fsuuid (temp_fsid),
layered modules like overlayfs require a persistent identifier.
While internal in-memory fs_devices->fsid must remain unique to
the kernel module, let s_uuid carry the original on-disk UUID.
Signed-off-by: Anand Jain <asj@kernel.org>
Signed-off-by: David Sterba <dsterba@suse.com>
| -rw-r--r-- | fs/btrfs/disk-io.c | 11 |
1 files changed, 10 insertions, 1 deletions
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c index a6203bcf16e28..ec13eac2b3d7b 100644 --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -3529,7 +3529,16 @@ int __cold open_ctree(struct super_block *sb, struct btrfs_fs_devices *fs_device /* Update the values for the current filesystem. */ sb->s_blocksize = sectorsize; sb->s_blocksize_bits = blksize_bits(sectorsize); - memcpy(&sb->s_uuid, fs_info->fs_devices->fsid, BTRFS_FSID_SIZE); + /* + * When temp_fsid is active, fs_devices->fsid is assigned a random UUID + * at mount. This inconsistent UUID causes issues for layered filesystems + * like OverlayFS. Since metadata_uuid may or may not be set, provide the + * on-disk UUID directly from the super_copy. + */ + if (fs_info->fs_devices->temp_fsid) + memcpy(&sb->s_uuid, fs_info->super_copy->fsid, BTRFS_FSID_SIZE); + else + memcpy(&sb->s_uuid, fs_info->fs_devices->fsid, BTRFS_FSID_SIZE); mutex_lock(&fs_info->chunk_mutex); ret = btrfs_read_sys_array(fs_info); |