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Commit 5e7dd2ab6b9bdfa60e19b8739e6b2a204fd4f477

Authored by NeilBrown
Committed by Linus Torvalds
1 parent 62de608da0
Exists in master and in 7 other branches imx_3.0.35_4.1.0, imx_3.10.17_1.0.1_ga, imx_3.10.53_1.1.0_ga, imx_3.14.28_1.0.0_ga, smarc-imx_3.10.53_1.1.0_ga, smarc-imx_3.14.28_1.0.0_ga, smarc-l5.0.0_1.0.0-ga

[PATCH] md: Fix 'rdev->nr_pending' count when retrying barrier requests 

When retrying a failed BIO_RW_BARRIER request, we need to keep the reference
in ->nr_pending over the whole retry.  Currently, we only hold the reference
if the failed request is the *last* one to finish - which is silly, because it
would normally be the first to finish.

So move the rdev_dec_pending call up into the didn't-fail branch.  As the rdev
isn't used in the later code, calling rdev_dec_pending earlier doesn't hurt.

Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

Showing 1 changed file with 4 additions and 5 deletions Side-by-side Diff

... ... @@ -319,6 +319,7 @@
319 319 set_bit(BarriersNotsupp, &conf->mirrors[mirror].rdev->flags);
320 320 set_bit(R1BIO_BarrierRetry, &r1_bio->state);
321 321 r1_bio->mddev->barriers_work = 0;
  322 + /* Don't rdev_dec_pending in this branch - keep it for the retry */
322 323 } else {
323 324 /*
324 325 * this branch is our 'one mirror IO has finished' event handler:
... ... @@ -365,6 +366,7 @@
365 366 }
366 367 }
367 368 }
  369 + rdev_dec_pending(conf->mirrors[mirror].rdev, conf->mddev);
368 370 }
369 371 /*
370 372 *
371 373  
... ... @@ -374,11 +376,9 @@
374 376 if (atomic_dec_and_test(&r1_bio->remaining)) {
375 377 if (test_bit(R1BIO_BarrierRetry, &r1_bio->state)) {
376 378 reschedule_retry(r1_bio);
377   - /* Don't dec_pending yet, we want to hold
378   - * the reference over the retry
379   - */
380 379 goto out;
381 380 }
  381 + /* it really is the end of this request */
382 382 if (test_bit(R1BIO_BehindIO, &r1_bio->state)) {
383 383 /* free extra copy of the data pages */
384 384 int i = bio->bi_vcnt;
... ... @@ -393,8 +393,6 @@
393 393 md_write_end(r1_bio->mddev);
394 394 raid_end_bio_io(r1_bio);
395 395 }
396   -
397   - rdev_dec_pending(conf->mirrors[mirror].rdev, conf->mddev);
398 396 out:
399 397 if (to_put)
400 398 bio_put(to_put);
... ... @@ -1414,6 +1412,7 @@
1414 1412 * Better resubmit without the barrier.
1415 1413 * We know which devices to resubmit for, because
1416 1414 * all others have had their bios[] entry cleared.
  1415 + * We already have a nr_pending reference on these rdevs.
1417 1416 */
1418 1417 int i;
1419 1418 clear_bit(R1BIO_BarrierRetry, &r1_bio->state);