@@ -3946,16 +3946,38 @@ static int process_extent(struct send_ctx *sctx,
if (sctx->parent_root && !sctx->cur_inode_new) {
ret = is_extent_unchanged(sctx, path, key);
if (ret < 0)
goto out;
if (ret) {
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,
sctx->cur_inode_size, &found_clone);
if (ret != -ENOENT && ret < 0)
goto out;
Hi Chen, Alexander, Jan, how about the following patch: it works for disknr==0 extents (to handle PREALLOC extents correctly, we need to add a new command, which will break existing btrfs-progs, because they are updated slower than the kernel side). ret = send_write_or_clone(sctx, path, key, found_clone); Thanks, Alex. On Thu, Nov 29, 2012 at 10:54 AM, Alexander Block <ablock84@gmail.com> wrote: > On Thu, Nov 29, 2012 at 4:11 AM, Chen Yang <chenyang.fnst@cn.fujitsu.com> wrote: >> when send/receive a sparse file, the holes of the original file >> will be filled with zero. The holes will be sent as ZERO streams, >> and it's unnecessary. >> >> So, I improved this by skipping the hole of file while sending. >> >> Signed-off-by: Cheng Yang <chenyang.fnst@cn.fujitsu.com> >> --- >> fs/btrfs/send.c | 6 ++++++ >> 1 files changed, 6 insertions(+), 0 deletions(-) >> >> diff --git a/fs/btrfs/send.c b/fs/btrfs/send.c >> index e78b297..1e1d59a 100644 >> --- a/fs/btrfs/send.c >> +++ b/fs/btrfs/send.c >> @@ -3718,6 +3718,7 @@ static int send_write_or_clone(struct send_ctx *sctx, >> u64 pos = 0; >> u64 len; >> u32 l; >> + u64 bytenr; >> u8 type; >> >> ei = btrfs_item_ptr(path->nodes[0], path->slots[0], >> @@ -3732,6 +3733,11 @@ static int send_write_or_clone(struct send_ctx *sctx, >> */ >> len = PAGE_CACHE_ALIGN(len); >> } else { >> + bytenr = btrfs_file_extent_disk_bytenr(path->nodes[0], ei); >> + if (bytenr == 0) { >> + ret = 0; >> + goto out; >> + } >> len = btrfs_file_extent_num_bytes(path->nodes[0], ei); >> } >> >> -- >> 1.7.7.6 >> >> -- >> 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 > > This won't work for incremental sends if I understand it correctly. If > the hole got punched into the file after the initial send, the data > will be unchanged on the receiving side when receiving incrementally. > -- > 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 -- 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