btrfs: delete chunk allocation attemp when setting block group ro
authorShaohua Li <shli@fb.com>
Fri, 9 Jan 2015 18:40:15 +0000 (10:40 -0800)
committerChris Mason <clm@fb.com>
Tue, 3 Feb 2015 03:25:20 +0000 (19:25 -0800)
commit2f0810880f082fa8ba66ab2c33b02e4ff9770a5e
treed6c4885a3890158235431db66fe625604b239974
parent289454ad26a2d752e04b07234a175feda9ec0f4e
btrfs: delete chunk allocation attemp when setting block group ro

Below test will fail currently:
      mkfs.ext4 -F /dev/sda
      btrfs-convert /dev/sda
      mount /dev/sda /mnt
      btrfs device add -f /dev/sdb /mnt
      btrfs balance start -v -dconvert=raid1 -mconvert=raid1 /mnt

The reason is there are some block groups with usage 0, but the whole
disk hasn't free space to allocate new chunk, so we even can't set such
block group readonly. This patch deletes the chunk allocation when
setting block group ro. For META, we already have reserve. But for
SYSTEM, we don't have, so the check_system_chunk is still required.

Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
fs/btrfs/extent-tree.c