Follow kernel code to return earlier for btrfs_previous_item() function.
Before this patch, btrfs_previous_item() doesn't use its min_objectid to
exit, this makes caller to check key to exit, and if caller doesn't
check, it will iterate all previous item.
This patch will check min_objectid and type, to early return and save
some time.
Signed-off-by: Qu Wenruo <quwenruo@xxxxxxxxxxxxxx>
---
ctree.c | 12 ++++++++++++
1 file changed, 12 insertions(+)
diff --git a/ctree.c b/ctree.c
index 079696e..a98ad18 100644
--- a/ctree.c
+++ b/ctree.c
@@ -2880,6 +2880,7 @@ int btrfs_previous_item(struct btrfs_root *root,
{
struct btrfs_key found_key;
struct extent_buffer *leaf;
+ u32 nritems;
int ret;
while(1) {
@@ -2891,9 +2892,20 @@ int btrfs_previous_item(struct btrfs_root *root,
path->slots[0]--;
}
leaf = path->nodes[0];
+ nritems = btrfs_header_nritems(leaf);
+ if (nritems == 0)
+ return 1;
+ if (path->slots[0] == nritems)
+ path->slots[0]--;
+
btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
+ if (found_key.objectid < min_objectid)
+ break;
if (found_key.type == type)
return 0;
+ if (found_key.objectid == min_objectid &&
+ found_key.type < type)
+ break;
}
return 1;
}
--
2.8.2
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