Btrfs: fix incorrect compression ratio detection
Steps to reproduce:
# mkfs.btrfs -f /dev/sdb
# mount -t btrfs /dev/sdb /mnt -o compress=lzo
# dd if=/dev/zero of=/mnt/data bs=$((33*4096)) count=1
after previous steps, inode will be detected as bad compression ratio,
and NOCOMPRESS flag will be set for that inode.
Reason is that compress have a max limit pages every time(128K), if a
132k write in, it will be splitted into two write(128k+4k), this bug
is a leftover for commit 68bb462d42a(Btrfs: don't compress for a small write)
Fix this problem by checking every time before compression, if it is a
small write(<=blocksize), we bail out and fall into nocompression directly.
Signed-off-by: Wang Shilong <wangshilong1991@gmail.com>
Reviewed-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
1 file changed