Btrfs: fix autodefrag with compression
PATCH 1/1 Btrfs: fix autodefrag with compression
The autodefrag code skips defrag when two extents are adjacent. But one big advantage for autodefrag is cutting down on the number of small extents, even when they are adjacent. This commit changes it to defrag all small extents.
This is especially useful when trying to use compression on slowly growing log files. We usually end up writing 4K or less at a time, so the compression code isn't able to compress across multiple pages.
Signed-off-by Chris Mason <[email protected]>
--- fs/btrfs/ioctl.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-)
fs/btrfs/ioctl.c +4 -2
@@ -1019,8 +1019,10 @@ static bool defrag_check_next_extent(struct inode *inode, struct extent_map *em)return false; next =defrag_lookup_extent (inode, em->start + em->len); -if (!next || next->block_start >=EXTENT_MAP_LAST_BYTE || - (em->block_start + em->block_len == next->block_start)) +if (!next || next->block_start >=EXTENT_MAP_LAST_BYTE ) + ret = false; +else if ((em->block_start + em->block_len == next->block_start) && + (em->block_len >128 *1024 && next->block_len >128 *1024 )) ret = false;free_extent_map (next);