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| author | Shilong Wang <wangshilong1991@gmail.com> | 2014-10-08 02:44:35 +0400 |
|---|---|---|
| committer | Chris Mason <clm@fb.com> | 2014-11-21 04:14:27 +0300 |
| commit | 4bcbb33255131adbe481c0467df26d654ce3bc78 (patch) | |
| tree | 13e3cd9b2f2cbd7e9380ffedeef1a139534ea50e /fs/btrfs/inode.c | |
| parent | 7bdcefc103849386ef7f3029dd94ecfd4a822a67 (diff) | |
| download | linux-4bcbb33255131adbe481c0467df26d654ce3bc78.tar.xz | |
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>
Diffstat (limited to 'fs/btrfs/inode.c')
| -rw-r--r-- | fs/btrfs/inode.c | 16 |
1 files changed, 8 insertions, 8 deletions
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index 6fed30c3f9ce..793e033cbd17 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -411,14 +411,6 @@ static noinline int compress_file_range(struct inode *inode, (start > 0 || end + 1 < BTRFS_I(inode)->disk_i_size)) btrfs_add_inode_defrag(NULL, inode); - /* - * skip compression for a small file range(<=blocksize) that - * isn't an inline extent, since it dosen't save disk space at all. - */ - if ((end - start + 1) <= blocksize && - (start > 0 || end + 1 < BTRFS_I(inode)->disk_i_size)) - goto cleanup_and_bail_uncompressed; - actual_end = min_t(u64, isize, end + 1); again: will_compress = 0; @@ -440,6 +432,14 @@ again: total_compressed = actual_end - start; + /* + * skip compression for a small file range(<=blocksize) that + * isn't an inline extent, since it dosen't save disk space at all. + */ + if (total_compressed <= blocksize && + (start > 0 || end + 1 < BTRFS_I(inode)->disk_i_size)) + goto cleanup_and_bail_uncompressed; + /* we want to make sure that amount of ram required to uncompress * an extent is reasonable, so we limit the total size in ram * of a compressed extent to 128k. This is a crucial number |