Btrfs: Replace the big fs_mutex with a collection of other locks

Extent alloctions are still protected by a large alloc_mutex.
Objectid allocations are covered by a objectid mutex
Other btree operations are protected by a lock on individual btree nodes

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

1 files changed, 8 insertions, 0 deletions

diff --git a/fs/btrfs/inode-map.c b/fs/btrfs/inode-map.c
index a0925eabdaa2..298346ae1481 100644
--- a/fs/btrfs/inode-map.c
+++ b/fs/btrfs/inode-map.c
@@ -69,6 +69,12 @@ int btrfs_find_free_objectid(struct btrfs_trans_handle *trans,
         struct btrfs_key search_key;
         u64 search_start = dirid;
 
+        mutex_lock(&root->objectid_mutex);
+        if (root->last_inode_alloc) {
+                *objectid = ++root->last_inode_alloc;
+                mutex_unlock(&root->objectid_mutex);
+                return 0;
+        }
         path = btrfs_alloc_path();
         BUG_ON(!path);
         search_start = root->last_inode_alloc;
@@ -124,9 +130,11 @@ found:
         btrfs_release_path(root, path);
         btrfs_free_path(path);
         BUG_ON(*objectid < search_start);
+        mutex_unlock(&root->objectid_mutex);
         return 0;
 error:
         btrfs_release_path(root, path);
         btrfs_free_path(path);
+        mutex_unlock(&root->objectid_mutex);
         return ret;
 }