[PATCH v3 06/22] ext4: pass out extent seq counter when mapping da blocks

[Zhang Yi]

From: Zhang Yi <yi.zhang@xxxxxxxxxx>

The iomap buffered write path does not hold any locks between querying
inode extent mapping information and performing buffered writes. It
relies on the sequence counter saved in the inode to detect stale
mappings.

Commit 07c440e8da8f ("ext4: pass out extent seq counter when mapping
blocks") added the m_seq field to ext4_map_blocks to pass out extent
sequence numbers, but it missed two callsites within
ext4_da_map_blocks(). These callsites are on the delayed allocation
path, which is also used in the iomap buffered write path. Pass out the
sequence counter to ensure stale mappings can be detected.

Signed-off-by: Zhang Yi <yi.zhang@xxxxxxxxxx>
---
 fs/ext4/inode.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index df21f6870ec4..5ffd6aeb3485 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -1929,7 +1929,7 @@ static int ext4_da_map_blocks(struct inode *inode, struct ext4_map_blocks *map)
 	ext4_check_map_extents_env(inode);
 
 	/* Lookup extent status tree firstly */
-	if (ext4_es_lookup_extent(inode, map->m_lblk, NULL, &es, NULL)) {
+	if (ext4_es_lookup_extent(inode, map->m_lblk, NULL, &es, &map->m_seq)) {
 		map->m_len = min_t(unsigned int, map->m_len,
 				   es.es_len - (map->m_lblk - es.es_lblk));
 
@@ -1982,7 +1982,7 @@ static int ext4_da_map_blocks(struct inode *inode, struct ext4_map_blocks *map)
 	 * is held in write mode, before inserting a new da entry in
 	 * the extent status tree.
 	 */
-	if (ext4_es_lookup_extent(inode, map->m_lblk, NULL, &es, NULL)) {
+	if (ext4_es_lookup_extent(inode, map->m_lblk, NULL, &es, &map->m_seq)) {
 		map->m_len = min_t(unsigned int, map->m_len,
 				   es.es_len - (map->m_lblk - es.es_lblk));
 
-- 
2.52.0