Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [PATCH 5.14 107/849] md/raid1: only allocate write behind bio for WriteMostly device | Date | Mon, 15 Nov 2021 17:53:10 +0100 |
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From: Guoqing Jiang <guoqing.jiang@linux.dev>
commit fd3b6975e9c11c4fa00965f82a0bfbb3b7b44101 upstream.
Commit 6607cd319b6b91bff94e90f798a61c031650b514 ("raid1: ensure write behind bio has less than BIO_MAX_VECS sectors") tried to guarantee the size of behind bio is not bigger than BIO_MAX_VECS sectors.
Unfortunately the same calltrace still could happen since an array could enable write-behind without write mostly device.
To match the manpage of mdadm (which says "write-behind is only attempted on drives marked as write-mostly"), we need to check WriteMostly flag to avoid such unexpected behavior.
[1]. https://bugzilla.kernel.org/show_bug.cgi?id=213181#c25
Cc: stable@vger.kernel.org # v5.12+ Cc: Jens Stutte <jens@chianterastutte.eu> Reported-by: Jens Stutte <jens@chianterastutte.eu> Signed-off-by: Guoqing Jiang <guoqing.jiang@linux.dev> Signed-off-by: Song Liu <songliubraving@fb.com> Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- drivers/md/raid1.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/md/raid1.c +++ b/drivers/md/raid1.c @@ -1496,7 +1496,7 @@ static void raid1_write_request(struct m if (!r1_bio->bios[i]) continue; - if (first_clone) { + if (first_clone && test_bit(WriteMostly, &rdev->flags)) { /* do behind I/O ? * Not if there are too many, or cannot * allocate memory, or a reader on WriteMostly
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