[PATCH 3/4] btrfs: relocation: Check cancel request after each extent found

Qu Wenruo
2019-12-03T06:43:05Z

When relocating data block groups with tons of small extents, or
large metadata block groups, there can be over 200,000 extents.

We will iterate all extents of such block group in relocate_block_group(),
where iteration itself can be kinda time-consuming.

So when user want to cancel the balance, the extent iteration loop can
be another target.

This patch will add the cancelling check in the extent iteration loop of
relocate_block_group() to make balance cancelling faster.

Signed-off-by: Qu Wenruo <wqu@suse.com>
---
fs/btrfs/relocation.c | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
index 533481a1f962..161d66f70190 100644
--- a/fs/btrfs/relocation.c
+++ b/fs/btrfs/relocation.c
@@ -4140,6 +4140,10 @@ static noinline_for_stack int relocate_block_group(struct reloc_control *rc)
break;
}
}
+ if (should_cancel_balance(fs_info)) {
+ err = -ECANCELED;
+ break;
+ }
}
if (trans && progress && err == -ENOSPC) {
ret = btrfs_force_chunk_alloc(trans, rc->block_group->flags);
--
2.24.0