[PATCH v2] zonefs: fix page reference and BIO leak

[Damien Le Moal <damien.lemoal@wdc.com>]

In zonefs_file_dio_append(), the pages obtained using
bio_iov_iter_get_pages() are not released on completion of the
REQ_OP_APPEND BIO, nor when bio_iov_iter_get_pages() fails.
Furthermore, a call to bio_put() is missing when
bio_iov_iter_get_pages() fails.

Fix these resource leaks by adding BIO resource release code (bio_put()i
and bio_release_pages()) at the end of the function after the BIO
execution and add a jump to this resource cleanup code in case of
bio_iov_iter_get_pages() failure.

While at it, also fix the call to task_io_account_write() to be passed
the correct BIO size instead of bio_iov_iter_get_pages() return value.

Reported-by: Christoph Hellwig <hch@lst.de>
Fixes: 02ef12a663c7 ("zonefs: use REQ_OP_ZONE_APPEND for sync DIO")
Cc: stable@vger.kernel.org
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
---
 fs/zonefs/super.c | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/fs/zonefs/super.c b/fs/zonefs/super.c
index ff5930be096c..bec47f2d074b 100644
--- a/fs/zonefs/super.c
+++ b/fs/zonefs/super.c
@@ -691,21 +691,23 @@ static ssize_t zonefs_file_dio_append(struct kiocb *iocb, struct iov_iter *from)
 		bio->bi_opf |= REQ_FUA;
 
 	ret = bio_iov_iter_get_pages(bio, from);
-	if (unlikely(ret)) {
-		bio_io_error(bio);
-		return ret;
-	}
+	if (unlikely(ret))
+		goto out_release;
+
 	size = bio->bi_iter.bi_size;
-	task_io_account_write(ret);
+	task_io_account_write(size);
 
 	if (iocb->ki_flags & IOCB_HIPRI)
 		bio_set_polled(bio, iocb);
 
 	ret = submit_bio_wait(bio);
 
+	zonefs_file_write_dio_end_io(iocb, size, ret, 0);
+
+out_release:
+	bio_release_pages(bio, false);
 	bio_put(bio);
 
-	zonefs_file_write_dio_end_io(iocb, size, ret, 0);
 	if (ret >= 0) {
 		iocb->ki_pos += size;
 		return size;
-- 
2.28.0