1 files changed, 61 insertions, 18 deletions

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index b83bf3308b5e..57c6dd38f071 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -1781,6 +1781,65 @@ static int ext4_bh_delay_or_unwritten(handle_t *handle, struct buffer_head *bh)
 }
 
 /*
+ * ext4_insert_delayed_block - adds a delayed block to the extents status
+ *                             tree, incrementing the reserved cluster/block
+ *                             count or making a pending reservation
+ *                             where needed
+ *
+ * @inode - file containing the newly added block
+ * @lblk - logical block to be added
+ *
+ * Returns 0 on success, negative error code on failure.
+ */
+static int ext4_insert_delayed_block(struct inode *inode, ext4_lblk_t lblk)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
+	int ret;
+	bool allocated = false;
+
+	/*
+	 * If the cluster containing lblk is shared with a delayed,
+	 * written, or unwritten extent in a bigalloc file system, it's
+	 * already been accounted for and does not need to be reserved.
+	 * A pending reservation must be made for the cluster if it's
+	 * shared with a written or unwritten extent and doesn't already
+	 * have one.  Written and unwritten extents can be purged from the
+	 * extents status tree if the system is under memory pressure, so
+	 * it's necessary to examine the extent tree if a search of the
+	 * extents status tree doesn't get a match.
+	 */
+	if (sbi->s_cluster_ratio == 1) {
+		ret = ext4_da_reserve_space(inode);
+		if (ret != 0)   /* ENOSPC */
+			goto errout;
+	} else {   /* bigalloc */
+		if (!ext4_es_scan_clu(inode, &ext4_es_is_delonly, lblk)) {
+			if (!ext4_es_scan_clu(inode,
+					      &ext4_es_is_mapped, lblk)) {
+				ret = ext4_clu_mapped(inode,
+						      EXT4_B2C(sbi, lblk));
+				if (ret < 0)
+					goto errout;
+				if (ret == 0) {
+					ret = ext4_da_reserve_space(inode);
+					if (ret != 0)   /* ENOSPC */
+						goto errout;
+				} else {
+					allocated = true;
+				}
+			} else {
+				allocated = true;
+			}
+		}
+	}
+
+	ret = ext4_es_insert_delayed_block(inode, lblk, allocated);
+
+errout:
+	return ret;
+}
+
+/*
  * This function is grabs code from the very beginning of
  * ext4_map_blocks, but assumes that the caller is from delayed write
  * time. This function looks up the requested blocks and sets the
@@ -1864,25 +1923,9 @@ add_delayed:
 		 * XXX: __block_prepare_write() unmaps passed block,
 		 * is it OK?
 		 */
-		/*
-		 * If the block was allocated from previously allocated cluster,
-		 * then we don't need to reserve it again. However we still need
-		 * to reserve metadata for every block we're going to write.
-		 */
-		if (EXT4_SB(inode->i_sb)->s_cluster_ratio == 1 ||
-		    !ext4_es_scan_clu(inode,
-				      &ext4_es_is_delayed, map->m_lblk)) {
-			ret = ext4_da_reserve_space(inode);
-			if (ret) {
-				/* not enough space to reserve */
-				retval = ret;
-				goto out_unlock;
-			}
-		}
 
-		ret = ext4_es_insert_extent(inode, map->m_lblk, map->m_len,
-					    ~0, EXTENT_STATUS_DELAYED);
-		if (ret) {
+		ret = ext4_insert_delayed_block(inode, map->m_lblk);
+		if (ret != 0) {
 			retval = ret;
 			goto out_unlock;
 		}