1 files changed, 19 insertions, 6 deletions

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index afc3ac5e57d7..d133edfcd449 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -4535,16 +4535,25 @@ int btrfs_delalloc_reserve_metadata(struct inode *inode, u64 num_bytes)
         int extra_reserve = 0;
         enum btrfs_reserve_flush_enum flush = BTRFS_RESERVE_FLUSH_ALL;
         int ret;
+        bool delalloc_lock = true;
 
-        /* Need to be holding the i_mutex here if we aren't free space cache */
-        if (btrfs_is_free_space_inode(inode))
+        /* If we are a free space inode we need to not flush since we will be in
+         * the middle of a transaction commit.  We also don't need the delalloc
+         * mutex since we won't race with anybody.  We need this mostly to make
+         * lockdep shut its filthy mouth.
+         */
+        if (btrfs_is_free_space_inode(inode)) {
                 flush = BTRFS_RESERVE_NO_FLUSH;
+                delalloc_lock = false;
+        }
 
         if (flush != BTRFS_RESERVE_NO_FLUSH &&
             btrfs_transaction_in_commit(root->fs_info))
                 schedule_timeout(1);
 
-        mutex_lock(&BTRFS_I(inode)->delalloc_mutex);
+        if (delalloc_lock)
+                mutex_lock(&BTRFS_I(inode)->delalloc_mutex);
+
         num_bytes = ALIGN(num_bytes, root->sectorsize);
 
         spin_lock(&BTRFS_I(inode)->lock);
@@ -4577,7 +4586,8 @@ int btrfs_delalloc_reserve_metadata(struct inode *inode, u64 num_bytes)
                         spin_lock(&BTRFS_I(inode)->lock);
                         calc_csum_metadata_size(inode, num_bytes, 0);
                         spin_unlock(&BTRFS_I(inode)->lock);
-                        mutex_unlock(&BTRFS_I(inode)->delalloc_mutex);
+                        if (delalloc_lock)
+                                mutex_unlock(&BTRFS_I(inode)->delalloc_mutex);
                         return ret;
                 }
         }
@@ -4616,7 +4626,8 @@ int btrfs_delalloc_reserve_metadata(struct inode *inode, u64 num_bytes)
                         btrfs_qgroup_free(root, num_bytes +
                                                 nr_extents * root->leafsize);
                 }
-                mutex_unlock(&BTRFS_I(inode)->delalloc_mutex);
+                if (delalloc_lock)
+                        mutex_unlock(&BTRFS_I(inode)->delalloc_mutex);
                 return ret;
         }
 
@@ -4628,7 +4639,9 @@ int btrfs_delalloc_reserve_metadata(struct inode *inode, u64 num_bytes)
         }
         BTRFS_I(inode)->reserved_extents += nr_extents;
         spin_unlock(&BTRFS_I(inode)->lock);
-        mutex_unlock(&BTRFS_I(inode)->delalloc_mutex);
+
+        if (delalloc_lock)
+                mutex_unlock(&BTRFS_I(inode)->delalloc_mutex);
 
         if (to_reserve)
                 trace_btrfs_space_reservation(root->fs_info,"delalloc",