1 files changed, 48 insertions, 0 deletions

diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index c0f202741e09..cd07a9c30ec3 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -257,6 +257,15 @@ void __cold extent_io_exit(void)
 	bioset_exit(&btrfs_bioset);
 }
 
+/*
+ * For the file_extent_tree, we want to hold the inode lock when we lookup and
+ * update the disk_i_size, but lockdep will complain because our io_tree we hold
+ * the tree lock and get the inode lock when setting delalloc.  These two things
+ * are unrelated, so make a class for the file_extent_tree so we don't get the
+ * two locking patterns mixed up.
+ */
+static struct lock_class_key file_extent_tree_class;
+
 void extent_io_tree_init(struct btrfs_fs_info *fs_info,
 			 struct extent_io_tree *tree, unsigned int owner,
 			 void *private_data)
@@ -268,6 +277,8 @@ void extent_io_tree_init(struct btrfs_fs_info *fs_info,
 	spin_lock_init(&tree->lock);
 	tree->private_data = private_data;
 	tree->owner = owner;
+	if (owner == IO_TREE_INODE_FILE_EXTENT)
+		lockdep_set_class(&tree->lock, &file_extent_tree_class);
 }
 
 void extent_io_tree_release(struct extent_io_tree *tree)
@@ -1568,6 +1579,43 @@ out:
 }
 
 /**
+ * find_contiguous_extent_bit: find a contiguous area of bits
+ * @tree - io tree to check
+ * @start - offset to start the search from
+ * @start_ret - the first offset we found with the bits set
+ * @end_ret - the final contiguous range of the bits that were set
+ * @bits - bits to look for
+ *
+ * set_extent_bit and clear_extent_bit can temporarily split contiguous ranges
+ * to set bits appropriately, and then merge them again.  During this time it
+ * will drop the tree->lock, so use this helper if you want to find the actual
+ * contiguous area for given bits.  We will search to the first bit we find, and
+ * then walk down the tree until we find a non-contiguous area.  The area
+ * returned will be the full contiguous area with the bits set.
+ */
+int find_contiguous_extent_bit(struct extent_io_tree *tree, u64 start,
+			       u64 *start_ret, u64 *end_ret, unsigned bits)
+{
+	struct extent_state *state;
+	int ret = 1;
+
+	spin_lock(&tree->lock);
+	state = find_first_extent_bit_state(tree, start, bits);
+	if (state) {
+		*start_ret = state->start;
+		*end_ret = state->end;
+		while ((state = next_state(state)) != NULL) {
+			if (state->start > (*end_ret + 1))
+				break;
+			*end_ret = state->end;
+		}
+		ret = 0;
+	}
+	spin_unlock(&tree->lock);
+	return ret;
+}
+
+/**
  * find_first_clear_extent_bit - find the first range that has @bits not set.
  * This range could start before @start.
  *