| From | Greg Kroah-Hartman <> | Subject | [ 25/73] block: fix max discard sectors limit | Date | Thu, 9 May 2013 15:25:15 -0700 |
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3.9-stable review patch. If anyone has any objections, please let me know.
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From: James Bottomley <JBottomley@Parallels.com>
commit 871dd9286e25330c8a581e5dacfa8b1dfe1dd641 upstream.
linux-v3.8-rc1 and later support for plug for blkdev_issue_discard with commit 0cfbcafcae8b7364b5fa96c2b26ccde7a3a296a9 (block: add plug for blkdev_issue_discard )
For example, 1) DISCARD rq-1 with size size 4GB 2) DISCARD rq-2 with size size 1GB
If these 2 discard requests get merged, final request size will be 5GB.
In this case, request's __data_len field may overflow as it can store max 4GB(unsigned int).
This issue was observed while doing mkfs.f2fs on 5GB SD card: https://lkml.org/lkml/2013/4/1/292
Info: sector size = 512 Info: total sectors = 11370496 (in 512bytes) Info: zone aligned segment0 blkaddr: 512 [ 257.789764] blk_update_request: bio idx 0 >= vcnt 0
mkfs process gets stuck in D state and I see the following in the dmesg:
[ 257.789733] __end_that: dev mmcblk0: type=1, flags=122c8081 [ 257.789764] sector 4194304, nr/cnr 2981888/4294959104 [ 257.789764] bio df3840c0, biotail df3848c0, buffer (null), len 1526726656 [ 257.789764] blk_update_request: bio idx 0 >= vcnt 0 [ 257.794921] request botched: dev mmcblk0: type=1, flags=122c8081 [ 257.794921] sector 4194304, nr/cnr 2981888/4294959104 [ 257.794921] bio df3840c0, biotail df3848c0, buffer (null), len 1526726656
This patch fixes this issue.
Reported-by: Max Filippov <jcmvbkbc@gmail.com> Signed-off-by: James Bottomley <JBottomley@Parallels.com> Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com> Tested-by: Max Filippov <jcmvbkbc@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- include/linux/blkdev.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -838,7 +838,7 @@ static inline unsigned int blk_queue_get unsigned int cmd_flags) { if (unlikely(cmd_flags & REQ_DISCARD)) - return q->limits.max_discard_sectors; + return min(q->limits.max_discard_sectors, UINT_MAX >> 9); if (unlikely(cmd_flags & REQ_WRITE_SAME)) return q->limits.max_write_same_sectors;
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