1 files changed, 83 insertions, 7 deletions

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 72dc1314925fc..14c19a38cd4fb 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -483,15 +483,73 @@ static void ext4_map_blocks_es_recheck(handle_t *handle,
 }
 #endif /* ES_AGGRESSIVE_TEST */
 
+static int ext4_map_query_blocks_next_in_leaf(handle_t *handle,
+			struct inode *inode, struct ext4_map_blocks *map,
+			unsigned int orig_mlen)
+{
+	struct ext4_map_blocks map2;
+	unsigned int status, status2;
+	int retval;
+
+	status = map->m_flags & EXT4_MAP_UNWRITTEN ?
+		EXTENT_STATUS_UNWRITTEN : EXTENT_STATUS_WRITTEN;
+
+	WARN_ON_ONCE(!(map->m_flags & EXT4_MAP_QUERY_LAST_IN_LEAF));
+	WARN_ON_ONCE(orig_mlen <= map->m_len);
+
+	/* Prepare map2 for lookup in next leaf block */
+	map2.m_lblk = map->m_lblk + map->m_len;
+	map2.m_len = orig_mlen - map->m_len;
+	map2.m_flags = 0;
+	retval = ext4_ext_map_blocks(handle, inode, &map2, 0);
+
+	if (retval <= 0) {
+		ext4_es_insert_extent(inode, map->m_lblk, map->m_len,
+				      map->m_pblk, status, false);
+		return map->m_len;
+	}
+
+	if (unlikely(retval != map2.m_len)) {
+		ext4_warning(inode->i_sb,
+			     "ES len assertion failed for inode "
+			     "%lu: retval %d != map->m_len %d",
+			     inode->i_ino, retval, map2.m_len);
+		WARN_ON(1);
+	}
+
+	status2 = map2.m_flags & EXT4_MAP_UNWRITTEN ?
+		EXTENT_STATUS_UNWRITTEN : EXTENT_STATUS_WRITTEN;
+
+	/*
+	 * If map2 is contiguous with map, then let's insert it as a single
+	 * extent in es cache and return the combined length of both the maps.
+	 */
+	if (map->m_pblk + map->m_len == map2.m_pblk &&
+			status == status2) {
+		ext4_es_insert_extent(inode, map->m_lblk,
+				      map->m_len + map2.m_len, map->m_pblk,
+				      status, false);
+		map->m_len += map2.m_len;
+	} else {
+		ext4_es_insert_extent(inode, map->m_lblk, map->m_len,
+				      map->m_pblk, status, false);
+	}
+
+	return map->m_len;
+}
+
 static int ext4_map_query_blocks(handle_t *handle, struct inode *inode,
 				 struct ext4_map_blocks *map, int flags)
 {
 	unsigned int status;
 	int retval;
+	unsigned int orig_mlen = map->m_len;
+	unsigned int query_flags = flags & EXT4_GET_BLOCKS_QUERY_LAST_IN_LEAF;
 
 	flags &= EXT4_EX_FILTER;
 	if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
-		retval = ext4_ext_map_blocks(handle, inode, map, flags);
+		retval = ext4_ext_map_blocks(handle, inode, map,
+					     flags | query_flags);
 	else
 		retval = ext4_ind_map_blocks(handle, inode, map, flags);
 
@@ -506,11 +564,23 @@ static int ext4_map_query_blocks(handle_t *handle, struct inode *inode,
 		WARN_ON(1);
 	}
 
-	status = map->m_flags & EXT4_MAP_UNWRITTEN ?
-			EXTENT_STATUS_UNWRITTEN : EXTENT_STATUS_WRITTEN;
-	ext4_es_insert_extent(inode, map->m_lblk, map->m_len,
-			      map->m_pblk, status, false);
-	return retval;
+	/*
+	 * No need to query next in leaf:
+	 * - if returned extent is not last in leaf or
+	 * - if the last in leaf is the full requested range
+	 */
+	if (!(map->m_flags & EXT4_MAP_QUERY_LAST_IN_LEAF) ||
+			((map->m_flags & EXT4_MAP_QUERY_LAST_IN_LEAF) &&
+			 (map->m_len == orig_mlen))) {
+		status = map->m_flags & EXT4_MAP_UNWRITTEN ?
+				EXTENT_STATUS_UNWRITTEN : EXTENT_STATUS_WRITTEN;
+		ext4_es_insert_extent(inode, map->m_lblk, map->m_len,
+				      map->m_pblk, status, false);
+		return retval;
+	}
+
+	return ext4_map_query_blocks_next_in_leaf(handle, inode, map,
+						  orig_mlen);
 }
 
 static int ext4_map_create_blocks(handle_t *handle, struct inode *inode,
@@ -624,6 +694,7 @@ int ext4_map_blocks(handle_t *handle, struct inode *inode,
 	struct extent_status es;
 	int retval;
 	int ret = 0;
+	unsigned int orig_mlen = map->m_len;
 #ifdef ES_AGGRESSIVE_TEST
 	struct ext4_map_blocks orig_map;
 
@@ -685,7 +756,12 @@ int ext4_map_blocks(handle_t *handle, struct inode *inode,
 		ext4_map_blocks_es_recheck(handle, inode, map,
 					   &orig_map, flags);
 #endif
-		goto found;
+		if (!(flags & EXT4_GET_BLOCKS_QUERY_LAST_IN_LEAF) ||
+				orig_mlen == map->m_len)
+			goto found;
+
+		if (flags & EXT4_GET_BLOCKS_QUERY_LAST_IN_LEAF)
+			map->m_len = orig_mlen;
 	}
 	/*
 	 * In the query cache no-wait mode, nothing we can do more if we