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From: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org
Subject: [PATCH] fat: Avoid oops when bdi->io_pages==0
Date: Sun, 30 Aug 2020 09:59:41 +0900	[thread overview]
Message-ID: <87ft85osn6.fsf@mail.parknet.co.jp> (raw)

On one system, there was bdi->io_pages==0. This seems to be the bug of
a driver somewhere, and should fix it though. Anyway, it is better to
avoid the divide-by-zero Oops.

So this check it.

Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Cc: <stable@vger.kernel.org>
---
 fs/fat/fatent.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/fat/fatent.c b/fs/fat/fatent.c
index f7e3304..98a1c4f 100644
--- a/fs/fat/fatent.c	2020-08-30 06:52:47.251564566 +0900
+++ b/fs/fat/fatent.c	2020-08-30 06:54:05.838319213 +0900
@@ -660,7 +660,7 @@ static void fat_ra_init(struct super_blo
 	if (fatent->entry >= ent_limit)
 		return;
 
-	if (ra_pages > sb->s_bdi->io_pages)
+	if (sb->s_bdi->io_pages && ra_pages > sb->s_bdi->io_pages)
 		ra_pages = rounddown(ra_pages, sb->s_bdi->io_pages);
 	reada_blocks = ra_pages << (PAGE_SHIFT - sb->s_blocksize_bits + 1);
 
_

-- 
OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>

             reply	other threads:[~2020-08-30  1:08 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-08-30  0:59 OGAWA Hirofumi [this message]
2020-08-30  1:21 ` [PATCH] fat: Avoid oops when bdi->io_pages==0 Matthew Wilcox
2020-08-30  1:54   ` OGAWA Hirofumi
2020-08-30  3:53     ` Matthew Wilcox
2020-08-30  9:04       ` OGAWA Hirofumi
2020-08-30 14:01 ` Sasha Levin
2020-08-30 14:16   ` OGAWA Hirofumi
2020-08-31 15:22 ` Jens Axboe
2020-08-31 16:37   ` OGAWA Hirofumi
2020-08-31 16:39     ` Jens Axboe
2020-08-31 16:56       ` Matthew Wilcox
2020-08-31 17:00         ` Jens Axboe
2020-08-31 17:39           ` OGAWA Hirofumi
2020-08-31 17:16       ` OGAWA Hirofumi
2020-08-31 17:19         ` Jens Axboe

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