[PATCH 1/3] ext4: Allow IO submission without io_end

[Jan Kara <jack@xxxxxxx>]

Allow submission of bio through ext4_bio_write_page() without io_end.
For the case where we are not converting unwritten extents we don't need
io_end for anything anyway.

Signed-off-by: Jan Kara <jack@xxxxxxx>
---
 fs/ext4/page-io.c | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/fs/ext4/page-io.c b/fs/ext4/page-io.c
index 208241b06662..a8a6caf4752a 100644
--- a/fs/ext4/page-io.c
+++ b/fs/ext4/page-io.c
@@ -298,23 +298,20 @@ static void ext4_end_bio(struct bio *bio)
 	ext4_io_end_t *io_end = bio->bi_private;
 	sector_t bi_sector = bio->bi_iter.bi_sector;
 
-	BUG_ON(!io_end);
 	bio->bi_end_io = NULL;
 
 	if (bio->bi_error) {
 		struct inode *inode = io_end->inode;
 
 		ext4_warning(inode->i_sb, "I/O error %d writing to inode %lu "
-			     "(offset %llu size %ld starting block %llu)",
+			     "(starting block %llu)",
 			     bio->bi_error, inode->i_ino,
-			     (unsigned long long) io_end->offset,
-			     (long) io_end->size,
 			     (unsigned long long)
 			     bi_sector >> (inode->i_blkbits - 9));
 		mapping_set_error(inode->i_mapping, bio->bi_error);
 	}
 
-	if (io_end->flag & EXT4_IO_END_UNWRITTEN) {
+	if (io_end && io_end->flag & EXT4_IO_END_UNWRITTEN) {
 		/*
 		 * Link bio into list hanging from io_end. We have to do it
 		 * atomically as bio completions can be racing against each
@@ -322,15 +319,17 @@ static void ext4_end_bio(struct bio *bio)
 		 */
 		bio->bi_private = xchg(&io_end->bio, bio);
 		ext4_put_io_end_defer(io_end);
-	} else {
+		return;
+	}
+	if (io_end) {
 		/*
 		 * Drop io_end reference early. Inode can get freed once
 		 * we finish the bio.
 		 */
 		ext4_put_io_end_defer(io_end);
-		ext4_finish_bio(bio);
-		bio_put(bio);
 	}
+	ext4_finish_bio(bio);
+	bio_put(bio);
 }
 
 void ext4_io_submit(struct ext4_io_submit *io)
@@ -366,7 +365,8 @@ static int io_submit_init_bio(struct ext4_io_submit *io,
 	bio->bi_iter.bi_sector = bh->b_blocknr * (bh->b_size >> 9);
 	bio->bi_bdev = bh->b_bdev;
 	bio->bi_end_io = ext4_end_bio;
-	bio->bi_private = ext4_get_io_end(io->io_end);
+	if (io->io_end)
+		bio->bi_private = ext4_get_io_end(io->io_end);
 	io->io_bio = bio;
 	io->io_next_block = bh->b_blocknr;
 	return 0;
-- 
2.12.0