Alex Lyakas
2013-Jan-09 17:39 UTC
[PATCH 1/2] Avoid sending disknr==0 extents when possible
Subject: [PATCH 1/2] Avoid sending disknr==0 extents in the following cases: 1) full send 2) new inode in a diff-send 3) when disknr==0 extents are added to the end of an inode Original-version-by: Chen Yang <chenyang.fnst@cn.fujitsu.com> Signed-off-by: Alex Lyakas <alex.btrfs@zadarastorage.com> --- fs/btrfs/send.c | 28 ++++++++++++++++++++++++++-- 1 file changed, 26 insertions(+), 2 deletions(-) diff --git a/fs/btrfs/send.c b/fs/btrfs/send.c index 5445454..5ab584f 100644 --- a/fs/btrfs/send.c +++ b/fs/btrfs/send.c @@ -3844,7 +3844,8 @@ static int is_extent_unchanged(struct send_ctx *sctx, btrfs_item_key_to_cpu(eb, &found_key, slot); if (found_key.objectid != key.objectid || found_key.type != key.type) { - ret = 0; + /* No need to send a no-data extent it in this case */ + ret = (left_disknr == 0) ? 1 : 0; goto out; } @@ -3870,7 +3871,8 @@ static int is_extent_unchanged(struct send_ctx *sctx, * This may only happen on the first iteration. */ if (found_key.offset + right_len <= ekey->offset) { - ret = 0; + /* No need to send a no-data extent it in this case */ + ret = (left_disknr == 0) ? 1 : 0; goto out; } @@ -3951,6 +3953,28 @@ static int process_extent(struct send_ctx *sctx, ret = 0; goto out; } + } else { + struct extent_buffer *eb; + struct btrfs_file_extent_item *ei; + u8 extent_type; + u64 extent_disknr; + + eb = path->nodes[0]; + ei = btrfs_item_ptr(eb, path->slots[0], + struct btrfs_file_extent_item); + + extent_type = btrfs_file_extent_type(eb, ei); + extent_disknr = btrfs_file_extent_disk_bytenr(eb, ei); + if (extent_type == BTRFS_FILE_EXTENT_REG && extent_disknr == 0) { + /* + * This is disknr=0 extent in a full-send or a new inode + * in a diff-send. Since we will send truncate command + * in finish_inode_if_needed anyways, the inode size will be + * correct, and we don''t have to send all-zero data. + */ + ret = 0; + goto out; + } } ret = find_extent_clone(sctx, path, key->objectid, key->offset, -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html