[PATCH] zonefs: do not use append if device does not support it

[Andreas Hindborg <nmi@metaspace.dk>]

From: "Andreas Hindborg (Samsung)" <nmi@metaspace.dk>

Zonefs will try to use `zonefs_file_dio_append()` for direct sync writes even if
device `max_zone_append_sectors` is zero. This will cause the IO to fail as the
io vector is truncated to zero. It also causes a call to
`invalidate_inode_pages2_range()` with end set to UINT_MAX, which is probably
not intentional. Thus, do not use append when device does not support it.

Signed-off-by: Andreas Hindborg (Samsung) <nmi@metaspace.dk>
---
 fs/zonefs/file.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/fs/zonefs/file.c b/fs/zonefs/file.c
index 132f01d3461f..c97fe2aa20b0 100644
--- a/fs/zonefs/file.c
+++ b/fs/zonefs/file.c
@@ -536,9 +536,11 @@ static ssize_t zonefs_write_checks(struct kiocb *iocb, struct iov_iter *from)
 static ssize_t zonefs_file_dio_write(struct kiocb *iocb, struct iov_iter *from)
 {
 	struct inode *inode = file_inode(iocb->ki_filp);
+	struct block_device *bdev = inode->i_sb->s_bdev;
 	struct zonefs_inode_info *zi = ZONEFS_I(inode);
 	struct zonefs_zone *z = zonefs_inode_zone(inode);
 	struct super_block *sb = inode->i_sb;
+	unsigned int max_append = bdev_max_zone_append_sectors(bdev);
 	bool sync = is_sync_kiocb(iocb);
 	bool append = false;
 	ssize_t ret, count;
@@ -581,7 +583,7 @@ static ssize_t zonefs_file_dio_write(struct kiocb *iocb, struct iov_iter *from)
 		append = sync;
 	}
 
-	if (append) {
+	if (append && max_append) {
 		ret = zonefs_file_dio_append(iocb, from);
 	} else {
 		/*

base-commit: 45a3e24f65e90a047bef86f927ebdc4c710edaa1
-- 
2.41.0