[PATCH AUTOSEL for 4.9 040/190] btrfs: fix a bogus warning when converting only data or metadata

From: Sasha Levin
Date: Thu Mar 08 2018 - 00:01:02 EST


From: Adam Borowski <kilobyte@xxxxxxxxxx>

[ Upstream commit 14506127979a5a3d0c5d9b4cc76ce9d4ec23b717 ]

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@xxxxxxxxxx>
Reviewed-by: Liu Bo <bo.li.liu@xxxxxxxxxx>
Signed-off-by: David Sterba <dsterba@xxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx>
---
fs/btrfs/volumes.c | 12 +++++++++---
1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 06a77e47957d..cc0f5383a55a 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -3764,6 +3764,7 @@ 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;
@@ -3860,11 +3861,16 @@ 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) {
--
2.14.1