[f2fs-dev] [PATCH v2] f2fs: fix to map blocks correctly for direct write

[Chao Yu via Linux-f2fs-devel <linux-f2fs-devel@lists.sourceforge.net>]

f2fs_map_blocks() supports to map continuous holes or preallocated
address, we should avoid setting F2FS_MAP_MAPPED for these cases
only, otherwise, it may fail f2fs_iomap_begin(), and make direct
write fallbacking to use buffered IO and flush, result in performance
regression.

Fixes: 9f0f6bf42714 ("f2fs: support to map continuous holes or preallocated address")
Reported-by: kernel test robot <oliver.sang@intel.com>
Closes: https://lore.kernel.org/oe-lkp/202409122103.e45aa13b-oliver.sang@intel.com
Cc: Cyril Hrubis <chrubis@suse.cz>
Signed-off-by: Chao Yu <chao@kernel.org>
---
v2:
- fix wrong commit tile
- clean up code and comment suggested by Jaegeuk
 fs/f2fs/data.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index 306b86b0595d..7d1bb9518a40 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -1676,7 +1676,8 @@ int f2fs_map_blocks(struct inode *inode, struct f2fs_map_blocks *map, int flag)
 		/* reserved delalloc block should be mapped for fiemap. */
 		if (blkaddr == NEW_ADDR)
 			map->m_flags |= F2FS_MAP_DELALLOC;
-		if (flag != F2FS_GET_BLOCK_DIO || !is_hole)
+		/* DIO READ and hole case, should not map the blocks. */
+		if (!(flag == F2FS_GET_BLOCK_DIO && is_hole && !map->m_may_create))
 			map->m_flags |= F2FS_MAP_MAPPED;
 
 		map->m_pblk = blkaddr;
-- 
2.40.1



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