f2fs: fix data corruption issue with hardware encryption

Direct IO can be used in case of hardware encryption. The following
scenario results into data corruption issue in this path -

Thread A -                          Thread B-
-> write file#1 in direct IO
                                    -> GC gets kicked in
                                    -> GC submitted bio on meta mapping
				       for file#1, but pending completion
-> write file#1 again with new data
   in direct IO
                                    -> GC bio gets completed now
                                    -> GC writes old data to the new
                                       location and thus file#1 is
				       corrupted.

Fix this by submitting and waiting for pending io on meta mapping
for direct IO case in f2fs_map_blocks().

Signed-off-by: Sahitya Tummala <stummala@codeaurora.org>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

1 files changed, 11 insertions, 0 deletions

diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index 8a831f17503e..00b37a1bd15c 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -1053,6 +1053,11 @@ int f2fs_map_blocks(struct inode *inode, struct f2fs_map_blocks *map,
 		map->m_flags = F2FS_MAP_MAPPED;
 		if (map->m_next_extent)
 			*map->m_next_extent = pgofs + map->m_len;
+
+		/* for hardware encryption, but to avoid potential issue in future */
+		if (flag == F2FS_GET_BLOCK_DIO)
+			f2fs_wait_on_block_writeback_range(inode,
+						map->m_pblk, map->m_len);
 		goto out;
 	}
 
@@ -1211,6 +1216,12 @@ skip:
 	goto next_dnode;
 
 sync_out:
+
+	/* for hardware encryption, but to avoid potential issue in future */
+	if (flag == F2FS_GET_BLOCK_DIO && map->m_flags & F2FS_MAP_MAPPED)
+		f2fs_wait_on_block_writeback_range(inode,
+						map->m_pblk, map->m_len);
+
 	if (flag == F2FS_GET_BLOCK_PRECACHE) {
 		if (map->m_flags & F2FS_MAP_MAPPED) {
 			unsigned int ofs = start_pgofs - map->m_lblk;