[PATCH 13/35] btrfs: reset max_extent_size properly

Josef Bacik
2018-08-30T21:46:07Z

If we use up our block group before allocating a new one we'll easily
get a max_extent_size that's set really really low, which will result in
a lot of fragmentation. We need to make sure we're resetting the
max_extent_size when we add a new chunk or add new space.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
---
fs/btrfs/extent-tree.c | 7 +++++++
1 file changed, 7 insertions(+)

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 22e1f9f55f4f..f4e7caf37d6c 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -4565,6 +4565,7 @@ static int do_chunk_alloc(struct btrfs_trans_handle *trans, u64 flags,
goto out;
} else {
ret = 1;
+ space_info->max_extent_size = 0;
}

space_info->force_alloc = CHUNK_ALLOC_NO_FORCE;
@@ -8064,11 +8065,17 @@ static int __btrfs_free_reserved_extent(struct btrfs_fs_info *fs_info,
if (pin)
pin_down_extent(fs_info, cache, start, len, 1);
else {
+ struct btrfs_space_info *space_info = cache->space_info;
+
if (btrfs_test_opt(fs_info, DISCARD))
ret = btrfs_discard_extent(fs_info, start, len, NULL,
BTRFS_CLEAR_OP_DISCARD);
btrfs_add_free_space(cache, start, len);
btrfs_free_reserved_bytes(cache, len, delalloc);
+
+ spin_lock(&space_info->lock);
+ space_info->max_extent_size = 0;
+ spin_unlock(&space_info->lock);
trace_btrfs_reserved_extent_free(fs_info, start, len);
}

--
2.14.3