[PATCH] md/raid5: Ensure stripe_fill happens on non-read IO with journal

[PATCH] md/raid5: Ensure stripe_fill happens on non-read IO with journal

[Logan Gunthorpe]

When doing degrade/recover tests using the journal a kernel BUG
is hit at drivers/md/raid5.c:4381 in handle_parity_checks5():

  BUG_ON(!test_bit(R5_UPTODATE, &dev->flags));

This was found to occur because handle_stripe_fill() was skipped
for stripes in the journal due to a condition in that function.
Thus blocks were not fetched and R5_UPTODATE was not set when
the code reached handle_parity_checks5().

To fix this, don't skip handle_stripe_fill() unless the stripe is
for read.

Fixes: 07e83364845e ("md/r5cache: shift complex rmw from read path to write path")
Link: https://lore.kernel.org/linux-raid/e05c4239-41a9-d2f7-3cfa-4aa9d2cea8c1@deltatee.com/
Suggested-by: Song Liu <song@kernel.org>
Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
---
 drivers/md/raid5.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 31a0cbf63384..4ec33fd62018 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -4047,7 +4047,7 @@ static void handle_stripe_fill(struct stripe_head *sh,
 		 * back cache (prexor with orig_page, and then xor with
 		 * page) in the read path
 		 */
-		if (s->injournal && s->failed) {
+		if (s->to_read && s->injournal && s->failed) {
 			if (test_bit(STRIPE_R5C_CACHING, &sh->state))
 				r5c_make_stripe_write_out(sh);
 			goto out;

base-commit: ba5f3643ff6eed7300fd0cfb327ecb48a8be3fb6
--
2.30.2

Re: [PATCH] md/raid5: Ensure stripe_fill happens on non-read IO with journal

[Song Liu]

On Thu, Aug 25, 2022 at 8:46 AM Logan Gunthorpe <logang@deltatee.com> wrote:
>
> When doing degrade/recover tests using the journal a kernel BUG
> is hit at drivers/md/raid5.c:4381 in handle_parity_checks5():
>
>   BUG_ON(!test_bit(R5_UPTODATE, &dev->flags));
>
> This was found to occur because handle_stripe_fill() was skipped
> for stripes in the journal due to a condition in that function.
> Thus blocks were not fetched and R5_UPTODATE was not set when
> the code reached handle_parity_checks5().
>
> To fix this, don't skip handle_stripe_fill() unless the stripe is
> for read.
>
> Fixes: 07e83364845e ("md/r5cache: shift complex rmw from read path to write path")
> Link: https://lore.kernel.org/linux-raid/e05c4239-41a9-d2f7-3cfa-4aa9d2cea8c1@deltatee.com/
> Suggested-by: Song Liu <song@kernel.org>
> Signed-off-by: Logan Gunthorpe <logang@deltatee.com>

Applied to md-next. Thanks!

Song

> ---
>  drivers/md/raid5.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
> index 31a0cbf63384..4ec33fd62018 100644
> --- a/drivers/md/raid5.c
> +++ b/drivers/md/raid5.c
> @@ -4047,7 +4047,7 @@ static void handle_stripe_fill(struct stripe_head *sh,
>                  * back cache (prexor with orig_page, and then xor with
>                  * page) in the read path
>                  */
> -               if (s->injournal && s->failed) {
> +               if (s->to_read && s->injournal && s->failed) {
>                         if (test_bit(STRIPE_R5C_CACHING, &sh->state))
>                                 r5c_make_stripe_write_out(sh);
>                         goto out;
>
> base-commit: ba5f3643ff6eed7300fd0cfb327ecb48a8be3fb6
> --
> 2.30.2