[PATCH 4/6] f2fs: don't set FI_PREALLOCATED_ALL for partial write

[Chao Yu]

In f2fs_preallocate_blocks(), if it is partial write in 4KB, it's not
necessary to call f2fs_map_blocks() and set FI_PREALLOCATED_ALL flag.

Cc: Eric Biggers <ebiggers@xxxxxxxxxx>
Signed-off-by: Chao Yu <chao@xxxxxxxxxx>
---
 fs/f2fs/file.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index 5c2f99ada6be..1a3c29a9a6a0 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -4561,13 +4561,14 @@ static int f2fs_preallocate_blocks(struct kiocb *iocb, struct iov_iter *iter,
 			return ret;
 	}
 
-	/* Do not preallocate blocks that will be written partially in 4KB. */
 	map.m_lblk = F2FS_BLK_ALIGN(pos);
 	map.m_len = F2FS_BYTES_TO_BLK(pos + count);
-	if (map.m_len > map.m_lblk)
-		map.m_len -= map.m_lblk;
-	else
-		map.m_len = 0;
+
+	/* Do not preallocate blocks that will be written partially in 4KB. */
+	if (map.m_len <= map.m_lblk)
+		return 0;
+
+	map.m_len -= map.m_lblk;
 	map.m_may_create = true;
 	if (dio) {
 		map.m_seg_type = f2fs_rw_hint_to_seg_type(inode->i_write_hint);
-- 
2.40.1