On fri, 2 Aug 2013 14:49:54 +0800, Liu Bo wrote:
> The rule originally comes from nocow writing, but snapshot-aware
> defrag is a different case, the extent has been writen and we're
> not going to change the extent but add a reference on the data.
>
> So we're able to allow such compressed extents to be merged into
> one bigger extent if they're pointing to the same data.
>
> Signed-off-by: Liu Bo <bo.li.liu@xxxxxxxxxx>
> ---
> fs/btrfs/inode.c | 13 ++++++++-----
> 1 file changed, 8 insertions(+), 5 deletions(-)
>
> diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
> index 55dda87..a7aeecc 100644
> --- a/fs/btrfs/inode.c
> +++ b/fs/btrfs/inode.c
> @@ -2229,7 +2229,7 @@ static noinline bool record_extent_backrefs(struct btrfs_path *path,
>
> static int relink_is_mergable(struct extent_buffer *leaf,
> struct btrfs_file_extent_item *fi,
> - u64 disk_bytenr)
> + u64 disk_bytenr, u8 compress)
> {
> if (btrfs_file_extent_disk_bytenr(leaf, fi) != disk_bytenr)
> return 0;
> @@ -2237,8 +2237,10 @@ static int relink_is_mergable(struct extent_buffer *leaf,
> if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_REG)
> return 0;
>
> - if (btrfs_file_extent_compression(leaf, fi) ||
> - btrfs_file_extent_encryption(leaf, fi) ||
> + if (btrfs_file_extent_compression(leaf, fi) != compress)
> + return 0;
> +
> + if (btrfs_file_extent_encryption(leaf, fi) ||
> btrfs_file_extent_other_encoding(leaf, fi))
> return 0;
>
> @@ -2382,8 +2384,9 @@ again:
> struct btrfs_file_extent_item);
> extent_len = btrfs_file_extent_num_bytes(leaf, fi);
>
> - if (relink_is_mergable(leaf, fi, new->bytenr) &&
> - extent_len + found_key.offset == start) {
> + if (extent_len + found_key.offset == start &&
> + relink_is_mergable(leaf, fi, new->bytenr,
> + new->compress_type)) {
There is a petty comment: Why not pass "new" to relink_is_mergable() directly?
The other code is OK.
Reviewed-by: Miao Xie <miaox@xxxxxxxxxxxxxx>
> btrfs_set_file_extent_num_bytes(leaf, fi,
> extent_len + len);
> btrfs_mark_buffer_dirty(leaf);
>
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