sector >= reshape_sector;
}
+enum stripe_result {
+ STRIPE_SUCCESS = 0,
+ STRIPE_RETRY,
+ STRIPE_SCHEDULE_AND_RETRY,
+ STRIPE_FAIL,
+};
+
+struct stripe_request_ctx {
+ /* the request had REQ_PREFLUSH, cleared after the first stripe_head */
+ bool do_flush;
+};
+
+static enum stripe_result make_stripe_request(struct mddev *mddev,
+ struct r5conf *conf, struct stripe_request_ctx *ctx,
+ sector_t logical_sector, struct bio *bi, int seq)
+{
+ const int rw = bio_data_dir(bi);
+ enum stripe_result ret;
+ struct stripe_head *sh;
+ sector_t new_sector;
+ int previous = 0;
+ int dd_idx;
+
+ if (unlikely(conf->reshape_progress != MaxSector)) {
+ /*
+ * Spinlock is needed as reshape_progress may be
+ * 64bit on a 32bit platform, and so it might be
+ * possible to see a half-updated value
+ * Of course reshape_progress could change after
+ * the lock is dropped, so once we get a reference
+ * to the stripe that we think it is, we will have
+ * to check again.
+ */
+ spin_lock_irq(&conf->device_lock);
+ if (ahead_of_reshape(mddev, logical_sector,
+ conf->reshape_progress)) {
+ previous = 1;
+ } else {
+ if (ahead_of_reshape(mddev, logical_sector,
+ conf->reshape_safe)) {
+ spin_unlock_irq(&conf->device_lock);
+ return STRIPE_SCHEDULE_AND_RETRY;
+ }
+ }
+ spin_unlock_irq(&conf->device_lock);
+ }
+
+ new_sector = raid5_compute_sector(conf, logical_sector, previous,
+ &dd_idx, NULL);
+ pr_debug("raid456: %s, sector %llu logical %llu\n", __func__,
+ new_sector, logical_sector);
+
+ sh = raid5_get_active_stripe(conf, new_sector, previous,
+ (bi->bi_opf & REQ_RAHEAD), 0);
+ if (unlikely(!sh)) {
+ /* cannot get stripe, just give-up */
+ bi->bi_status = BLK_STS_IOERR;
+ return STRIPE_FAIL;
+ }
+
+ if (unlikely(previous)) {
+ /*
+ * Expansion might have moved on while waiting for a
+ * stripe, so we must do the range check again.
+ * Expansion could still move past after this
+ * test, but as we are holding a reference to
+ * 'sh', we know that if that happens,
+ * STRIPE_EXPANDING will get set and the expansion
+ * won't proceed until we finish with the stripe.
+ */
+ int must_retry = 0;
+ spin_lock_irq(&conf->device_lock);
+ if (!ahead_of_reshape(mddev, logical_sector,
+ conf->reshape_progress))
+ /* mismatch, need to try again */
+ must_retry = 1;
+ spin_unlock_irq(&conf->device_lock);
+ if (must_retry) {
+ ret = STRIPE_SCHEDULE_AND_RETRY;
+ goto out_release;
+ }
+ }
+
+ if (read_seqcount_retry(&conf->gen_lock, seq)) {
+ /* Might have got the wrong stripe_head by accident */
+ ret = STRIPE_RETRY;
+ goto out_release;
+ }
+
+ if (test_bit(STRIPE_EXPANDING, &sh->state) ||
+ !add_stripe_bio(sh, bi, dd_idx, rw, previous)) {
+ /*
+ * Stripe is busy expanding or add failed due to
+ * overlap. Flush everything and wait a while.
+ */
+ md_wakeup_thread(mddev->thread);
+ ret = STRIPE_SCHEDULE_AND_RETRY;
+ goto out_release;
+ }
+
+ if (stripe_can_batch(sh))
+ stripe_add_to_batch_list(conf, sh);
+
+ if (ctx->do_flush) {
+ set_bit(STRIPE_R5C_PREFLUSH, &sh->state);
+ /* we only need flush for one stripe */
+ ctx->do_flush = false;
+ }
+
+ set_bit(STRIPE_HANDLE, &sh->state);
+ clear_bit(STRIPE_DELAYED, &sh->state);
+ if ((!sh->batch_head || sh == sh->batch_head) &&
+ (bi->bi_opf & REQ_SYNC) &&
+ !test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
+ atomic_inc(&conf->preread_active_stripes);
+
+ release_stripe_plug(mddev, sh);
+ return STRIPE_SUCCESS;
+
+out_release:
+ raid5_release_stripe(sh);
+ return ret;
+}
+
static bool raid5_make_request(struct mddev *mddev, struct bio * bi)
{
struct r5conf *conf = mddev->private;
- int dd_idx;
- sector_t new_sector;
sector_t logical_sector, last_sector;
- struct stripe_head *sh;
+ struct stripe_request_ctx ctx = {};
const int rw = bio_data_dir(bi);
+ enum stripe_result res;
DEFINE_WAIT(w);
bool do_prepare;
- bool do_flush = false;
if (unlikely(bi->bi_opf & REQ_PREFLUSH)) {
int ret = log_handle_flush_request(conf, bi);
* if r5l_handle_flush_request() didn't clear REQ_PREFLUSH,
* we need to flush journal device
*/
- do_flush = bi->bi_opf & REQ_PREFLUSH;
+ ctx.do_flush = bi->bi_opf & REQ_PREFLUSH;
}
if (!md_write_start(mddev, bi))
md_account_bio(mddev, &bi);
prepare_to_wait(&conf->wait_for_overlap, &w, TASK_UNINTERRUPTIBLE);
for (; logical_sector < last_sector; logical_sector += RAID5_STRIPE_SECTORS(conf)) {
- int previous;
int seq;
do_prepare = false;
retry:
seq = read_seqcount_begin(&conf->gen_lock);
- previous = 0;
if (do_prepare)
prepare_to_wait(&conf->wait_for_overlap, &w,
TASK_UNINTERRUPTIBLE);
- if (unlikely(conf->reshape_progress != MaxSector)) {
- /* spinlock is needed as reshape_progress may be
- * 64bit on a 32bit platform, and so it might be
- * possible to see a half-updated value
- * Of course reshape_progress could change after
- * the lock is dropped, so once we get a reference
- * to the stripe that we think it is, we will have
- * to check again.
- */
- spin_lock_irq(&conf->device_lock);
- if (ahead_of_reshape(mddev, logical_sector,
- conf->reshape_progress)) {
- previous = 1;
- } else {
- if (ahead_of_reshape(mddev, logical_sector,
- conf->reshape_safe)) {
- spin_unlock_irq(&conf->device_lock);
- schedule();
- do_prepare = true;
- goto retry;
- }
- }
- spin_unlock_irq(&conf->device_lock);
- }
-
- new_sector = raid5_compute_sector(conf, logical_sector,
- previous,
- &dd_idx, NULL);
- pr_debug("raid456: raid5_make_request, sector %llu logical %llu\n",
- (unsigned long long)new_sector,
- (unsigned long long)logical_sector);
- sh = raid5_get_active_stripe(conf, new_sector, previous,
- (bi->bi_opf & REQ_RAHEAD), 0);
- if (unlikely(!sh)) {
- /* cannot get stripe, just give-up */
- bi->bi_status = BLK_STS_IOERR;
+ res = make_stripe_request(mddev, conf, &ctx, logical_sector,
+ bi, seq);
+ if (res == STRIPE_FAIL)
break;
- }
-
- if (unlikely(previous)) {
- /* expansion might have moved on while waiting for a
- * stripe, so we must do the range check again.
- * Expansion could still move past after this
- * test, but as we are holding a reference to
- * 'sh', we know that if that happens,
- * STRIPE_EXPANDING will get set and the expansion
- * won't proceed until we finish with the stripe.
- */
- int must_retry = 0;
- spin_lock_irq(&conf->device_lock);
- if (!ahead_of_reshape(mddev, logical_sector,
- conf->reshape_progress))
- /* mismatch, need to try again */
- must_retry = 1;
- spin_unlock_irq(&conf->device_lock);
- if (must_retry) {
- raid5_release_stripe(sh);
- schedule();
- do_prepare = true;
- goto retry;
- }
- }
- if (read_seqcount_retry(&conf->gen_lock, seq)) {
- /* Might have got the wrong stripe_head by accident */
- raid5_release_stripe(sh);
+ if (res == STRIPE_RETRY)
goto retry;
- }
- if (test_bit(STRIPE_EXPANDING, &sh->state) ||
- !add_stripe_bio(sh, bi, dd_idx, rw, previous)) {
- /*
- * Stripe is busy expanding or add failed due to
- * overlap. Flush everything and wait a while.
- */
- md_wakeup_thread(mddev->thread);
- raid5_release_stripe(sh);
+ if (res == STRIPE_SCHEDULE_AND_RETRY) {
schedule();
do_prepare = true;
goto retry;
}
-
- if (stripe_can_batch(sh))
- stripe_add_to_batch_list(conf, sh);
-
- if (do_flush) {
- set_bit(STRIPE_R5C_PREFLUSH, &sh->state);
- /* we only need flush for one stripe */
- do_flush = false;
- }
-
- set_bit(STRIPE_HANDLE, &sh->state);
- clear_bit(STRIPE_DELAYED, &sh->state);
- if ((!sh->batch_head || sh == sh->batch_head) &&
- (bi->bi_opf & REQ_SYNC) &&
- !test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
- atomic_inc(&conf->preread_active_stripes);
-
- release_stripe_plug(mddev, sh);
}
+
finish_wait(&conf->wait_for_overlap, &w);
if (rw == WRITE)
projects / kernel.git / commitdiff