Re: [PATCH] block: Fix dio_bio_alloc() to set BIO_PAGE_PINNED
From: David Hildenbrand
Date: Mon Jun 12 2023 - 14:16:36 EST
On 12.06.23 18:51, David Howells wrote:
Fix dio_bio_alloc() to set BIO_PAGE_PINNED, not BIO_PAGE_REFFED, so that
the bio code unpins the pinned pages rather than putting a ref on them.
The issue was causing:
WARNING: CPU: 6 PID: 2220 at mm/gup.c:76 try_get_folio
This can be caused by creating a file on a loopback UDF filesystem, opening
it O_DIRECT and making two writes to it from the same source buffer.
Fixes: 1ccf164ec866 ("block: Use iov_iter_extract_pages() and page pinning in direct-io.c")
Reported-by: kernel test robot <oliver.sang@xxxxxxxxx>
Closes: https://lore.kernel.org/oe-lkp/202306120931.a9606b88-oliver.sang@xxxxxxxxx
Signed-off-by: David Howells <dhowells@xxxxxxxxxx>
cc: Christoph Hellwig <hch@xxxxxxxxxxxxx>
cc: David Hildenbrand <david@xxxxxxxxxx>
cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
cc: Jens Axboe <axboe@xxxxxxxxx>
cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
cc: Jan Kara <jack@xxxxxxx>
cc: Jeff Layton <jlayton@xxxxxxxxxx>
cc: Jason Gunthorpe <jgg@xxxxxxxxxx>
cc: Logan Gunthorpe <logang@xxxxxxxxxxxx>
cc: Hillf Danton <hdanton@xxxxxxxx>
cc: Christian Brauner <brauner@xxxxxxxxxx>
cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
cc: linux-fsdevel@xxxxxxxxxxxxxxx
cc: linux-block@xxxxxxxxxxxxxxx
cc: linux-kernel@xxxxxxxxxxxxxxx
cc: linux-mm@xxxxxxxxx
---
fs/direct-io.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/fs/direct-io.c b/fs/direct-io.c
index 14049204cac8..04e810826ee8 100644
--- a/fs/direct-io.c
+++ b/fs/direct-io.c
@@ -415,7 +415,8 @@ dio_bio_alloc(struct dio *dio, struct dio_submit *sdio,
else
bio->bi_end_io = dio_bio_end_io;
/* for now require references for all pages */
Does the comment still hold?
- bio_set_flag(bio, BIO_PAGE_REFFED);
+ if (dio->need_unpin)
+ bio_set_flag(bio, BIO_PAGE_PINNED);
sdio->bio = bio;
sdio->logical_offset_in_bio = sdio->cur_page_fs_offset;
}
--
Cheers,
David / dhildenb