[PATCH] f2fs: skip f2fs_preallocate_blocks() for overwrite case

[Chao Yu]

In f2fs_file_write_iter(), let's use f2fs_overwrite_io() to
check whethere it is overwrite case, for such case, we can skip
f2fs_preallocate_blocks() in order to avoid f2fs_do_map_lock(),
which may be blocked by checkpoint() potentially.

Signed-off-by: Chao Yu <chao@xxxxxxxxxx>
---
 fs/f2fs/file.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index 13deae03df06..51fecb2f4db5 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -4321,6 +4321,10 @@ static ssize_t f2fs_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
 		preallocated = true;
 		target_size = iocb->ki_pos + iov_iter_count(from);
 
+		if (f2fs_overwrite_io(inode, iocb->ki_pos,
+						iov_iter_count(from)))
+			goto write;
+
 		err = f2fs_preallocate_blocks(iocb, from);
 		if (err) {
 out_err:
-- 
2.32.0