* [PATCH 1/2] Avoid sending disknr==0 extents when possible
2013-01-09 17:37 [PATCH 0/2] send: Avoid sending disknr==0 and PREALLOC extents when possible Alex Lyakas
@ 2013-01-09 17:39 ` Alex Lyakas
2013-01-09 17:41 ` [PATCH 2/2] On a diff-send, avoid sending PREALLOC extent Alex Lyakas
2013-01-10 3:25 ` [PATCH 0/2] send: Avoid sending disknr==0 and PREALLOC extents when possible Chen Yang
2 siblings, 0 replies; 7+ messages in thread
From: Alex Lyakas @ 2013-01-09 17:39 UTC (permalink / raw)
To: Alexander Block, Jan Schmidt, linux-btrfs; +Cc: Arne Jansen, Chen Yang
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
^ permalink raw reply related [flat|nested] 7+ messages in thread* [PATCH 2/2] On a diff-send, avoid sending PREALLOC extent
2013-01-09 17:37 [PATCH 0/2] send: Avoid sending disknr==0 and PREALLOC extents when possible Alex Lyakas
2013-01-09 17:39 ` [PATCH 1/2] Avoid sending disknr==0 " Alex Lyakas
@ 2013-01-09 17:41 ` Alex Lyakas
2013-01-14 18:45 ` Josef Bacik
2013-01-10 3:25 ` [PATCH 0/2] send: Avoid sending disknr==0 and PREALLOC extents when possible Chen Yang
2 siblings, 1 reply; 7+ messages in thread
From: Alex Lyakas @ 2013-01-09 17:41 UTC (permalink / raw)
To: Alexander Block, Jan Schmidt, linux-btrfs; +Cc: Arne Jansen
Subject: [PATCH 2/2] On a diff-send, avoid sending PREALLOC extents, if the
parent root has only PREALLOC extents on an appropriate
file range.
This does not fully avoids sending PREALLOC extents, because on full-send or
new inode we need a new send command to do that. But this patch improves
the situation by handling diff-sends.
Signed-off-by: Alex Lyakas <alex.btrfs@zadarastorage.com>
---
fs/btrfs/send.c | 150 +++++++++++++++++++++++++++++++++++++++++++++++++++++--
1 file changed, 146 insertions(+), 4 deletions(-)
diff --git a/fs/btrfs/send.c b/fs/btrfs/send.c
index 5ab584f..456bc3e 100644
--- a/fs/btrfs/send.c
+++ b/fs/btrfs/send.c
@@ -3763,6 +3763,144 @@ out:
return ret;
}
+static int is_prealloc_extent_unchanged(struct send_ctx *sctx,
+ struct btrfs_path *left_path,
+ struct btrfs_key *ekey)
+{
+ int ret = 0;
+ struct btrfs_key key;
+ struct btrfs_path *path = NULL;
+ struct extent_buffer *eb;
+ int slot;
+ struct btrfs_key found_key;
+ struct btrfs_file_extent_item *ei;
+ u64 left_len;
+ u64 right_len;
+ u8 right_type;
+
+ eb = left_path->nodes[0];
+ slot = left_path->slots[0];
+ ei = btrfs_item_ptr(eb, slot, struct btrfs_file_extent_item);
+ left_len = btrfs_file_extent_num_bytes(eb, ei);
+
+ /*
+ * The logic is similar, but much simpler than in is_extent_unchanged().
+ * We need to check extents on the parent root, and make sure that only
+ * PREALLOC extents are on the same file range as our current extent.
+ *
+ * Following comments will refer to these graphics. L is the left
+ * extents which we are checking at the moment. 1-8 are the right
+ * extents that we iterate.
+ *
+ * |-----L-----|
+ * |-1-|-2a-|-3-|-4-|-5-|-6-|
+ *
+ * |-----L-----|
+ * |--1--|-2b-|...(same as above)
+ *
+ * Alternative situation. Happens on files where extents got split.
+ * |-----L-----|
+ * |-----------7-----------|-6-|
+ *
+ * Alternative situation. Happens on files which got larger.
+ * |-----L-----|
+ * |-8-|
+ * Nothing follows after 8.
+ */
+
+ path = alloc_path_for_send();
+ if (!path)
+ return -ENOMEM;
+
+ key.objectid = ekey->objectid;
+ key.type = BTRFS_EXTENT_DATA_KEY;
+ key.offset = ekey->offset;
+ ret = btrfs_search_slot_for_read(sctx->parent_root, &key, path, 0, 0);
+ if (ret < 0)
+ goto out;
+ if (ret) {
+ ret = 0;
+ goto out;
+ }
+
+ /*
+ * Handle special case where the right side has no extents at all.
+ */
+ eb = path->nodes[0];
+ slot = path->slots[0];
+ btrfs_item_key_to_cpu(eb, &found_key, slot);
+ if (found_key.objectid != key.objectid ||
+ found_key.type != key.type) {
+ /*
+ * We need to send a "prealloc" command, which we don't have yet,
+ * just send this extent fully.
+ */
+ ret = 0;
+ goto out;
+ }
+
+ key = found_key;
+ while (key.offset < ekey->offset + left_len) {
+ ei = btrfs_item_ptr(eb, slot, struct btrfs_file_extent_item);
+ right_type = btrfs_file_extent_type(eb, ei);
+ right_len = btrfs_file_extent_num_bytes(eb, ei);
+
+ if (right_type != BTRFS_FILE_EXTENT_PREALLOC) {
+ ret = 0;
+ goto out;
+ }
+
+ /*
+ * Are we at extent 8? If yes, we know the extent is changed.
+ * This may only happen on the first iteration.
+ */
+ if (found_key.offset + right_len <= ekey->offset) {
+ /*
+ * We need to send a "prealloc" command, which we don't have yet,
+ * just send this extent fully.
+ */
+ ret = 0;
+ goto out;
+ }
+
+ /* The right extent is also PREALLOC, so up to here we are ok,
continue checking */
+
+ ret = btrfs_next_item(sctx->parent_root, path);
+ if (ret < 0)
+ goto out;
+ if (!ret) {
+ eb = path->nodes[0];
+ slot = path->slots[0];
+ btrfs_item_key_to_cpu(eb, &found_key, slot);
+ }
+ if (ret || found_key.objectid != key.objectid ||
+ found_key.type != key.type) {
+ key.offset += right_len;
+ break;
+ } else {
+ if (found_key.offset != key.offset + right_len) {
+ /* Should really not happen */
+ ret = -EIO;
+ goto out;
+ }
+ }
+ key = found_key;
+ }
+
+ /*
+ * We're now behind the left extent (treat as unchanged) or at the end
+ * of the right side (treat as changed).
+ */
+ if (key.offset >= ekey->offset + left_len)
+ ret = 1;
+ else
+ ret = 0;
+
+out:
+ btrfs_free_path(path);
+ return ret;
+}
+
static int is_extent_unchanged(struct send_ctx *sctx,
struct btrfs_path *left_path,
struct btrfs_key *ekey)
@@ -3786,15 +3924,15 @@ static int is_extent_unchanged(struct send_ctx *sctx,
u8 left_type;
u8 right_type;
- path = alloc_path_for_send();
- if (!path)
- return -ENOMEM;
-
eb = left_path->nodes[0];
slot = left_path->slots[0];
ei = btrfs_item_ptr(eb, slot, struct btrfs_file_extent_item);
left_type = btrfs_file_extent_type(eb, ei);
+ if (left_type == BTRFS_FILE_EXTENT_PREALLOC) {
+ ret = is_prealloc_extent_unchanged(sctx, left_path, ekey);
+ goto out;
+ }
if (left_type != BTRFS_FILE_EXTENT_REG) {
ret = 0;
goto out;
@@ -3825,6 +3963,10 @@ static int is_extent_unchanged(struct send_ctx *sctx,
* Nothing follows after 8.
*/
+ path = alloc_path_for_send();
+ if (!path)
+ return -ENOMEM;
+
key.objectid = ekey->objectid;
key.type = BTRFS_EXTENT_DATA_KEY;
key.offset = ekey->offset;
--
1.7.9.5
^ permalink raw reply related [flat|nested] 7+ messages in thread* Re: [PATCH 0/2] send: Avoid sending disknr==0 and PREALLOC extents when possible
2013-01-09 17:37 [PATCH 0/2] send: Avoid sending disknr==0 and PREALLOC extents when possible Alex Lyakas
2013-01-09 17:39 ` [PATCH 1/2] Avoid sending disknr==0 " Alex Lyakas
2013-01-09 17:41 ` [PATCH 2/2] On a diff-send, avoid sending PREALLOC extent Alex Lyakas
@ 2013-01-10 3:25 ` Chen Yang
2013-01-10 8:46 ` Alex Lyakas
2 siblings, 1 reply; 7+ messages in thread
From: Chen Yang @ 2013-01-10 3:25 UTC (permalink / raw)
To: Alex Lyakas; +Cc: Alexander Block, Jan Schmidt, linux-btrfs, Arne Jansen
Hi, Alex
The patches can only solve part of questions, but some like "punch holes" problems
as Alexander wrote are still unsolved. So I think these patches are unnecessary
if adding new command would help to solve all the questions.
Chen.
On 2013-1-9 4:11, Alex Lyakas wrote:
> These two patches address the issue of sending unneeded zero data for
> disknr==0 and PREALLOC extents.
> There is room for additional improvement for PREALLOC extents, but it
> requires adding a new command, so for
> now this is not addressed.
>
> Please review and comment.
>
> Thanks,
> Alex.
>
> Alex Lyakas (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
> On a diff-send, avoid sending PREALLOC extents, if the parent root
> has only PREALLOC extents on an appropriate file range.
>
> fs/btrfs/send.c | 178 +++++++++++++++++++++++++++++++++++++++++++++++++++++--
> 1 file changed, 172 insertions(+), 6 deletions(-)
>
> --
> 1.7.9.5
>
^ permalink raw reply [flat|nested] 7+ messages in thread