btrfs: fix a bogus warning when converting only data or metadata

If your filesystem has, eg, data:raid0 metadata:raid1, and you run "btrfs
balance -dconvert=raid1", the meta.target field will be uninitialized.
That's otherwise ok, as it's unused except for this warning.

Thus, let's use the existing set of raid levels for the comparison.

As a side effect, non-convert balances will now nag about data>metadata.

Signed-off-by: Adam Borowski <kilobyte@angband.pl>
Reviewed-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index ab8a66d852f91cb04206361a551b8c57760c9c40..02bbc4c8c755034adde891ec2006ebaec05996dd 100644 (file)
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -3755,6 +3755,7 @@ int btrfs_balance(struct btrfs_balance_control *bctl,
                  struct btrfs_ioctl_balance_args *bargs)
 {
        struct btrfs_fs_info *fs_info = bctl->fs_info;
+       u64 meta_target, data_target;
        u64 allowed;
        int mixed = 0;
        int ret;
@@ -3851,11 +3852,16 @@ int btrfs_balance(struct btrfs_balance_control *bctl,
                }
        } while (read_seqretry(&fs_info->profiles_lock, seq));
 
-       if (btrfs_get_num_tolerated_disk_barrier_failures(bctl->meta.target) <
-               btrfs_get_num_tolerated_disk_barrier_failures(bctl->data.target)) {
+       /* if we're not converting, the target field is uninitialized */
+       meta_target = (bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT) ?
+               bctl->meta.target : fs_info->avail_metadata_alloc_bits;
+       data_target = (bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT) ?
+               bctl->data.target : fs_info->avail_data_alloc_bits;
+       if (btrfs_get_num_tolerated_disk_barrier_failures(meta_target) <
+               btrfs_get_num_tolerated_disk_barrier_failures(data_target)) {
                btrfs_warn(fs_info,
                           "metadata profile 0x%llx has lower redundancy than data profile 0x%llx",
-                          bctl->meta.target, bctl->data.target);
+                          meta_target, data_target);
        }
 
        if (bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) {