Btrfs: make send's file extent item search more efficient
Instead of looking for a file extent item, process it, release the path
and do a btree search for the next file extent item, just process all
file extent items in a leaf without intermediate btree searches. This way
we save cpu and we're not blocking other tasks or affecting concurrency on
the btree, because send's paths use the commit root and skip btree node/leaf
locking.
Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com>
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
diff --git a/fs/btrfs/send.c b/fs/btrfs/send.c
index c96e879..4d31f72 100644
--- a/fs/btrfs/send.c
+++ b/fs/btrfs/send.c
@@ -4573,17 +4573,25 @@
key.objectid = sctx->cmp_key->objectid;
key.type = BTRFS_EXTENT_DATA_KEY;
key.offset = 0;
- while (1) {
- ret = btrfs_search_slot_for_read(root, &key, path, 1, 0);
- if (ret < 0)
- goto out;
- if (ret) {
- ret = 0;
- goto out;
- }
+ ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
+ if (ret < 0)
+ goto out;
+ while (1) {
eb = path->nodes[0];
slot = path->slots[0];
+
+ if (slot >= btrfs_header_nritems(eb)) {
+ ret = btrfs_next_leaf(root, path);
+ if (ret < 0) {
+ goto out;
+ } else if (ret > 0) {
+ ret = 0;
+ break;
+ }
+ continue;
+ }
+
btrfs_item_key_to_cpu(eb, &found_key, slot);
if (found_key.objectid != key.objectid ||
@@ -4596,8 +4604,7 @@
if (ret < 0)
goto out;
- btrfs_release_path(path);
- key.offset = found_key.offset + 1;
+ path->slots[0]++;
}
out: