/usr/src/kernel-patches/lustre/patches/raid5-stripe-by-stripe-handling-rhel5.patch is in linux-patch-lustre 1.8.5+dfsg-3ubuntu1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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--- linux-2.6.18-53.orig/drivers/md/raid5.c 2007-12-28 14:55:08.000000000 +0800
+++ linux-2.6.18-53/drivers/md/raid5.c 2007-12-28 18:52:08.000000000 +0800
@@ -2626,6 +2626,35 @@ static int raid5_issue_flush(request_que
return ret;
}
+static inline int raid5_expanding_overlap(raid5_conf_t *conf, struct bio *bi)
+{
+ sector_t first_sector, last_sector;
+
+ if (likely(conf->expand_progress == MaxSector))
+ return 0;
+
+ first_sector = bi->bi_sector & ~((sector_t)STRIPE_SECTORS-1);
+ last_sector = bi->bi_sector + (bi->bi_size>>9);
+
+ return (first_sector < conf->expand_progress &&
+ last_sector >= conf->expand_lo);
+}
+
+static inline int raid5_redo_bio(raid5_conf_t *conf, struct bio *bi, int disks, sector_t sector)
+{
+ int redo = 0;
+
+ if (likely(conf->expand_progress == MaxSector))
+ return 0;
+
+ spin_lock_irq(&conf->device_lock);
+ redo = (raid5_expanding_overlap(conf, bi) ||
+ (unlikely(sector < conf->expand_progress) &&
+ disks == conf->previous_raid_disks));
+ spin_unlock_irq(&conf->device_lock);
+ return redo;
+}
+
static int make_request(request_queue_t *q, struct bio * bi)
{
mddev_t *mddev = q->queuedata;
@@ -2636,6 +2665,14 @@ static int make_request(request_queue_t
struct stripe_head *sh;
const int rw = bio_data_dir(bi);
int remaining;
+ sector_t stripe, sectors, block, r_sector, b_sector;
+ int sectors_per_chunk = conf->chunk_size >> 9;
+ int stripes_per_chunk, sectors_per_block;
+ int sectors_per_stripe;
+ int i, j;
+
+ DEFINE_WAIT(w);
+ int disks, data_disks;
atomic_inc(&conf->in_reqs_in_queue);
@@ -2653,105 +2690,136 @@ static int make_request(request_queue_t
else
atomic_inc(&conf->reads_in);
-
logical_sector = bi->bi_sector & ~((sector_t)STRIPE_SECTORS-1);
last_sector = bi->bi_sector + (bi->bi_size>>9);
bi->bi_next = NULL;
bi->bi_phys_segments = 1; /* over-loaded to count active stripes */
- for (;logical_sector < last_sector; logical_sector += STRIPE_SECTORS) {
- DEFINE_WAIT(w);
- int disks, data_disks;
-
- retry:
- prepare_to_wait(&conf->wait_for_overlap, &w, TASK_UNINTERRUPTIBLE);
- if (likely(conf->expand_progress == MaxSector))
- disks = conf->raid_disks;
- else {
- /* spinlock is needed as expand_progress may be
- * 64bit on a 32bit platform, and so it might be
- * possible to see a half-updated value
- * Ofcourse expand_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);
- disks = conf->raid_disks;
- if (logical_sector >= conf->expand_progress)
- disks = conf->previous_raid_disks;
- else {
- if (logical_sector >= conf->expand_lo) {
- spin_unlock_irq(&conf->device_lock);
- schedule();
- goto retry;
- }
- }
- spin_unlock_irq(&conf->device_lock);
- }
- data_disks = disks - conf->max_degraded;
+ sectors = bi->bi_size >> 9;
+ stripes_per_chunk = conf->chunk_size / STRIPE_SIZE;
- new_sector = raid5_compute_sector(logical_sector, disks, data_disks,
- &dd_idx, &pd_idx, conf);
- PRINTK("raid5: make_request, sector %llu logical %llu\n",
- (unsigned long long)new_sector,
- (unsigned long long)logical_sector);
+redo_bio:
+ /* stripe by stripe handle needs a stable raid layout, so if this
+ * reuqest covers the expanding region, wait it over.
+ * Furthermore, we may get here with partial request handled, so
+ * wait for the bi_phys_segment to be 1 also. -jay */
+ spin_lock_irq(&conf->device_lock);
+ wait_event_lock_irq(conf->wait_for_overlap,
+ (bi->bi_phys_segments == 1) &&
+ !raid5_expanding_overlap(conf, bi),
+ conf->device_lock,
+ (unplug_slaves(conf->mddev), atomic_inc(&conf->expanding_overlap)));
+
+ disks = conf->raid_disks;
+ if (unlikely(logical_sector >= conf->expand_progress))
+ disks = conf->previous_raid_disks;
+ data_disks = disks - conf->max_degraded;
+ spin_unlock_irq(&conf->device_lock);
- sh = get_active_stripe(conf, new_sector, disks, pd_idx, (bi->bi_rw&RWA_MASK));
- if (sh) {
- if (unlikely(conf->expand_progress != MaxSector)) {
- /* 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 (logical_sector < conf->expand_progress &&
- disks == conf->previous_raid_disks)
- /* mismatch, need to try again */
- must_retry = 1;
- spin_unlock_irq(&conf->device_lock);
- if (must_retry) {
- release_stripe(sh);
- goto retry;
+ /* compute the block # */
+ sectors_per_stripe = STRIPE_SECTORS * data_disks;
+ sectors_per_block = stripes_per_chunk * sectors_per_stripe;
+
+ block = logical_sector & ~((sector_t)sectors_per_block - 1);
+ sector_div(block, sectors_per_block);
+
+repeat:
+ stripe = block * (sectors_per_block / data_disks);
+ b_sector = stripe * data_disks;
+ /* iterate through all stripes in this block,
+ * where block is a set of internal stripes
+ * which covers chunk */
+
+ for (i = 0; i < stripes_per_chunk && sectors > 0; i++) {
+ r_sector = b_sector + (i * STRIPE_SECTORS);
+ sh = NULL;
+ /* iterrate through all pages in the stripe */
+ for (j = 0; j < data_disks && sectors > 0; j++) {
+ DEFINE_WAIT(w);
+
+ if (r_sector + STRIPE_SECTORS <= bi->bi_sector ||
+ r_sector >= last_sector) {
+ r_sector += sectors_per_chunk;
+ continue;
+ }
+
+retry:
+ prepare_to_wait(&conf->wait_for_overlap, &w, TASK_UNINTERRUPTIBLE);
+ new_sector = raid5_compute_sector(r_sector, disks,
+ data_disks, &dd_idx,
+ &pd_idx, conf);
+ if (sh == NULL) {
+ sh = get_active_stripe(conf, new_sector, disks, pd_idx,
+ (bi->bi_rw&RWA_MASK));
+ if (sh) {
+ /* we're handling the bio stripe by stripe, so when we found
+ * the raid layout has been changed, we have to redo the
+ * whole bio because we don't which sectors in it has been
+ * done, and which is not done. -jay */
+ if (raid5_redo_bio(conf, bi, disks, logical_sector))
+ goto redo_bio;
+
+ if (test_bit(STRIPE_EXPANDING, &sh->state)) {
+ /* Stripe is busy expanding or
+ * add failed due to overlap. Flush everything
+ * and wait a while
+ */
+ release_stripe(sh);
+ sh = NULL;
+ raid5_unplug_device(mddev->queue);
+ schedule();
+ goto retry;
+ }
+ } else {
+ /* cannot get stripe for read-ahead, just give-up */
+ finish_wait(&conf->wait_for_overlap, &w);
+ clear_bit(BIO_UPTODATE, &bi->bi_flags);
+ sectors = 0;
+ break;
}
}
+
/* FIXME what if we get a false positive because these
* are being updated.
*/
- if (logical_sector >= mddev->suspend_lo &&
- logical_sector < mddev->suspend_hi) {
+ if (r_sector >= mddev->suspend_lo &&
+ r_sector < mddev->suspend_hi) {
+ handle_stripe(sh, NULL);
release_stripe(sh);
+ sh = NULL;
schedule();
goto retry;
}
- if (test_bit(STRIPE_EXPANDING, &sh->state) ||
- !add_stripe_bio(sh, bi, dd_idx, (bi->bi_rw&RW_MASK))) {
- /* Stripe is busy expanding or
- * add failed due to overlap. Flush everything
- * and wait a while
- */
- raid5_unplug_device(mddev->queue);
+ if (!add_stripe_bio(sh, bi, dd_idx, (bi->bi_rw&RW_MASK))) {
+ handle_stripe(sh, NULL);
release_stripe(sh);
+ sh = NULL;
+ raid5_unplug_device(mddev->queue);
schedule();
goto retry;
}
finish_wait(&conf->wait_for_overlap, &w);
+
+ BUG_ON (new_sector != stripe);
+ sectors -= STRIPE_SECTORS;
+ if (bi->bi_sector > r_sector)
+ sectors += bi->bi_sector - r_sector;
+ if (r_sector + STRIPE_SECTORS > last_sector)
+ sectors += r_sector + STRIPE_SECTORS - last_sector;
+ r_sector += sectors_per_chunk;
+ }
+ if (sh) {
handle_stripe(sh, NULL);
release_stripe(sh);
- } else {
- /* cannot get stripe for read-ahead, just give-up */
- clear_bit(BIO_UPTODATE, &bi->bi_flags);
- finish_wait(&conf->wait_for_overlap, &w);
- break;
+ sh = NULL;
}
-
+ stripe += STRIPE_SECTORS;
}
+ block++;
+ if (sectors > 0)
+ goto repeat;
+
spin_lock_irq(&conf->device_lock);
remaining = --bi->bi_phys_segments;
spin_unlock_irq(&conf->device_lock);
@@ -3439,6 +3507,8 @@ static void status (struct seq_file *seq
atomic_read(&conf->active_stripes),
atomic_read(&conf->in_reqs_in_queue),
atomic_read(&conf->out_reqs_in_queue));
+ seq_printf (seq, "\t\t%u expanding overlap\n",
+ atomic_read(&conf->expanding_overlap));
#if RAID5_DEBUG
seq_printf (seq, "\n");
printall(seq, conf);
diff -pur linux-2.6.18-53.orig/include/linux/raid/raid5.h linux-2.6.18-53/include/linux/raid/raid5.h
--- linux-2.6.18-53.orig/include/linux/raid/raid5.h 2007-12-28 14:55:08.000000000 +0800
+++ linux-2.6.18-53/include/linux/raid/raid5.h 2007-12-28 18:09:37.000000000 +0800
@@ -278,6 +278,7 @@ struct raid5_private_data {
atomic_t bit_delayed;
atomic_t in_reqs_in_queue;
atomic_t out_reqs_in_queue;
+ atomic_t expanding_overlap;
};
typedef struct raid5_private_data raid5_conf_t;
|