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Message-Id: <20240425113746.335530-8-kernel@pankajraghav.com>
Date: Thu, 25 Apr 2024 13:37:42 +0200
From: "Pankaj Raghav (Samsung)" <kernel@...kajraghav.com>
To: willy@...radead.org,
djwong@...nel.org,
brauner@...nel.org,
david@...morbit.com,
chandan.babu@...cle.com,
akpm@...ux-foundation.org
Cc: linux-fsdevel@...r.kernel.org,
hare@...e.de,
linux-kernel@...r.kernel.org,
linux-mm@...ck.org,
linux-xfs@...r.kernel.org,
mcgrof@...nel.org,
gost.dev@...sung.com,
p.raghav@...sung.com
Subject: [PATCH v4 07/11] iomap: fix iomap_dio_zero() for fs bs > system page size
From: Pankaj Raghav <p.raghav@...sung.com>
iomap_dio_zero() will pad a fs block with zeroes if the direct IO size
< fs block size. iomap_dio_zero() has an implicit assumption that fs block
size < page_size. This is true for most filesystems at the moment.
If the block size > page size, this will send the contents of the page
next to zero page(as len > PAGE_SIZE) to the underlying block device,
causing FS corruption.
iomap is a generic infrastructure and it should not make any assumptions
about the fs block size and the page size of the system.
Signed-off-by: Pankaj Raghav <p.raghav@...sung.com>
Reviewed-by: Darrick J. Wong <djwong@...nel.org>
---
fs/iomap/direct-io.c | 13 +++++++++++--
1 file changed, 11 insertions(+), 2 deletions(-)
diff --git a/fs/iomap/direct-io.c b/fs/iomap/direct-io.c
index f3b43d223a46..5f481068de5b 100644
--- a/fs/iomap/direct-io.c
+++ b/fs/iomap/direct-io.c
@@ -239,14 +239,23 @@ static void iomap_dio_zero(const struct iomap_iter *iter, struct iomap_dio *dio,
struct page *page = ZERO_PAGE(0);
struct bio *bio;
- bio = iomap_dio_alloc_bio(iter, dio, 1, REQ_OP_WRITE | REQ_SYNC | REQ_IDLE);
+ WARN_ON_ONCE(len > (BIO_MAX_VECS * PAGE_SIZE));
+
+ bio = iomap_dio_alloc_bio(iter, dio, BIO_MAX_VECS,
+ REQ_OP_WRITE | REQ_SYNC | REQ_IDLE);
fscrypt_set_bio_crypt_ctx(bio, inode, pos >> inode->i_blkbits,
GFP_KERNEL);
+
bio->bi_iter.bi_sector = iomap_sector(&iter->iomap, pos);
bio->bi_private = dio;
bio->bi_end_io = iomap_dio_bio_end_io;
- __bio_add_page(bio, page, len, 0);
+ while (len) {
+ unsigned int io_len = min_t(unsigned int, len, PAGE_SIZE);
+
+ __bio_add_page(bio, page, io_len, 0);
+ len -= io_len;
+ }
iomap_dio_submit_bio(iter, dio, bio, pos);
}
--
2.34.1
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