[PATCH] f2fs: allow direct read for zoned device

[Jaegeuk Kim]

This reverts dbf8e63f48af ("f2fs: remove device type check for direct IO"),
and apply the below first version, since it contributed out-of-order DIO writes.

For zoned devices, f2fs forbids direct IO and forces buffered IO
to serialize write IOs. However, the constraint does not apply to
read IOs.

Cc: stable@xxxxxxxxxxxxxxx
Fixes: dbf8e63f48af ("f2fs: remove device type check for direct IO")
Signed-off-by: Eunhee Rho <eunhee83.rho@xxxxxxxxxxx>
Signed-off-by: Jaegeuk Kim <jaegeuk@xxxxxxxxxx>
---
 fs/f2fs/f2fs.h | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 2ed00111a399..a0b2c8626a75 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -4535,7 +4535,12 @@ static inline bool f2fs_force_buffered_io(struct inode *inode,
 	/* disallow direct IO if any of devices has unaligned blksize */
 	if (f2fs_is_multi_device(sbi) && !sbi->aligned_blksize)
 		return true;
-
+	/*
+	 * for blkzoned device, fallback direct IO to buffered IO, so
+	 * all IOs can be serialized by log-structured write.
+	 */
+	if (f2fs_sb_has_blkzoned(sbi) && (rw == WRITE))
+		return true;
 	if (f2fs_lfs_mode(sbi) && (rw == WRITE)) {
 		if (block_unaligned_IO(inode, iocb, iter))
 			return true;
-- 
2.38.0.rc1.362.ged0d419d3c-goog