Btrfs: leave spinning on lookup and map the leaf
On lookup we only want to read the inode item, so leave the path spinning. Also
we're just wholesale reading the leaf off, so map the leaf so we don't do a
bunch of kmap/kunmaps. Thanks,
Signed-off-by: Josef Bacik <josef@redhat.com>
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 6228a30..dc8fb2b 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -2493,6 +2493,7 @@
path = btrfs_alloc_path();
BUG_ON(!path);
+ path->leave_spinning = 1;
memcpy(&location, &BTRFS_I(inode)->location, sizeof(location));
ret = btrfs_lookup_inode(NULL, root, path, &location, 0);
@@ -2502,6 +2503,12 @@
leaf = path->nodes[0];
inode_item = btrfs_item_ptr(leaf, path->slots[0],
struct btrfs_inode_item);
+ if (!leaf->map_token)
+ map_private_extent_buffer(leaf, (unsigned long)inode_item,
+ sizeof(struct btrfs_inode_item),
+ &leaf->map_token, &leaf->kaddr,
+ &leaf->map_start, &leaf->map_len,
+ KM_USER1);
inode->i_mode = btrfs_inode_mode(leaf, inode_item);
inode->i_nlink = btrfs_inode_nlink(leaf, inode_item);
@@ -2539,6 +2546,11 @@
if (!maybe_acls)
cache_no_acl(inode);
+ if (leaf->map_token) {
+ unmap_extent_buffer(leaf, leaf->map_token, KM_USER1);
+ leaf->map_token = NULL;
+ }
+
btrfs_free_path(path);
inode_item = NULL;