Btrfs: Use a mutex in the extent buffer for tree block locking

This replaces the use of the page cache lock bit for locking, which wasn't
suitable for block size < page size and couldn't be used recursively.

The mutexes alone don't fix either problem, but they are the first step.

Signed-off-by: Chris Mason <chris.mason@oracle.com>

1 files changed, 1 insertions, 6 deletions

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index ccd49322f793..c51cd11de206 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -1451,7 +1451,7 @@ static int pin_down_bytes(struct btrfs_root *root, u64 bytenr, u32 num_bytes,
                 struct extent_buffer *buf;
                 buf = btrfs_find_tree_block(root, bytenr, num_bytes);
                 if (buf) {
-                        if (!btrfs_try_tree_lock(buf) &&
+                        if (btrfs_try_tree_lock(buf) &&
                             btrfs_buffer_uptodate(buf, 0)) {
                                 u64 transid =
                                     root->fs_info->running_transaction->transid;
@@ -3345,11 +3345,6 @@ int btrfs_read_block_groups(struct btrfs_root *root)
                 set_state_private(block_group_cache, found_key.objectid,
                                   (unsigned long)cache);
 
-                /* hack for now */
-                if (cache->flags & BTRFS_BLOCK_GROUP_METADATA) {
-                        cache_block_group(root->fs_info->extent_root,
-                                          cache);
-                }
                 if (key.objectid >=
                     btrfs_super_total_bytes(&info->super_copy))
                         break;