1 files changed, 197 insertions, 22 deletions

diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 0689173fd9f5..c5439dce0295 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -551,6 +551,8 @@ static void ops_run_io(struct stripe_head *sh, struct stripe_head_state *s)
                                 rw = WRITE_FUA;
                         else
                                 rw = WRITE;
+                        if (test_bit(R5_Discard, &sh->dev[i].flags))
+                                rw |= REQ_DISCARD;
                 } else if (test_and_clear_bit(R5_Wantread, &sh->dev[i].flags))
                         rw = READ;
                 else if (test_and_clear_bit(R5_WantReplace,
@@ -1174,8 +1176,11 @@ ops_run_biodrain(struct stripe_head *sh, struct dma_async_tx_descriptor *tx)
                                         set_bit(R5_WantFUA, &dev->flags);
                                 if (wbi->bi_rw & REQ_SYNC)
                                         set_bit(R5_SyncIO, &dev->flags);
-                                tx = async_copy_data(1, wbi, dev->page,
-                                        dev->sector, tx);
+                                if (wbi->bi_rw & REQ_DISCARD)
+                                        set_bit(R5_Discard, &dev->flags);
+                                else
+                                        tx = async_copy_data(1, wbi, dev->page,
+                                                dev->sector, tx);
                                 wbi = r5_next_bio(wbi, dev->sector);
                         }
                 }
@@ -1191,7 +1196,7 @@ static void ops_complete_reconstruct(void *stripe_head_ref)
         int pd_idx = sh->pd_idx;
         int qd_idx = sh->qd_idx;
         int i;
-        bool fua = false, sync = false;
+        bool fua = false, sync = false, discard = false;
 
         pr_debug("%s: stripe %llu\n", __func__,
                 (unsigned long long)sh->sector);
@@ -1199,13 +1204,15 @@ static void ops_complete_reconstruct(void *stripe_head_ref)
         for (i = disks; i--; ) {
                 fua |= test_bit(R5_WantFUA, &sh->dev[i].flags);
                 sync |= test_bit(R5_SyncIO, &sh->dev[i].flags);
+                discard |= test_bit(R5_Discard, &sh->dev[i].flags);
         }
 
         for (i = disks; i--; ) {
                 struct r5dev *dev = &sh->dev[i];
 
                 if (dev->written || i == pd_idx || i == qd_idx) {
-                        set_bit(R5_UPTODATE, &dev->flags);
+                        if (!discard)
+                                set_bit(R5_UPTODATE, &dev->flags);
                         if (fua)
                                 set_bit(R5_WantFUA, &dev->flags);
                         if (sync)
@@ -1241,6 +1248,18 @@ ops_run_reconstruct5(struct stripe_head *sh, struct raid5_percpu *percpu,
         pr_debug("%s: stripe %llu\n", __func__,
                 (unsigned long long)sh->sector);
 
+        for (i = 0; i < sh->disks; i++) {
+                if (pd_idx == i)
+                        continue;
+                if (!test_bit(R5_Discard, &sh->dev[i].flags))
+                        break;
+        }
+        if (i >= sh->disks) {
+                atomic_inc(&sh->count);
+                set_bit(R5_Discard, &sh->dev[pd_idx].flags);
+                ops_complete_reconstruct(sh);
+                return;
+        }
         /* check if prexor is active which means only process blocks
          * that are part of a read-modify-write (written)
          */
@@ -1285,10 +1304,24 @@ ops_run_reconstruct6(struct stripe_head *sh, struct raid5_percpu *percpu,
 {
         struct async_submit_ctl submit;
         struct page **blocks = percpu->scribble;
-        int count;
+        int count, i;
 
         pr_debug("%s: stripe %llu\n", __func__, (unsigned long long)sh->sector);
 
+        for (i = 0; i < sh->disks; i++) {
+                if (sh->pd_idx == i || sh->qd_idx == i)
+                        continue;
+                if (!test_bit(R5_Discard, &sh->dev[i].flags))
+                        break;
+        }
+        if (i >= sh->disks) {
+                atomic_inc(&sh->count);
+                set_bit(R5_Discard, &sh->dev[sh->pd_idx].flags);
+                set_bit(R5_Discard, &sh->dev[sh->qd_idx].flags);
+                ops_complete_reconstruct(sh);
+                return;
+        }
+
         count = set_syndrome_sources(blocks, sh);
 
         atomic_inc(&sh->count);
@@ -2408,11 +2441,11 @@ static int add_stripe_bio(struct stripe_head *sh, struct bio *bi, int dd_idx, in
                 if (sector >= sh->dev[dd_idx].sector + STRIPE_SECTORS)
                         set_bit(R5_OVERWRITE, &sh->dev[dd_idx].flags);
         }
-        spin_unlock_irq(&sh->stripe_lock);
 
         pr_debug("added bi b#%llu to stripe s#%llu, disk %d.\n",
                 (unsigned long long)(*bip)->bi_sector,
                 (unsigned long long)sh->sector, dd_idx);
+        spin_unlock_irq(&sh->stripe_lock);
 
         if (conf->mddev->bitmap && firstwrite) {
                 bitmap_startwrite(conf->mddev->bitmap, sh->sector,
@@ -2479,10 +2512,8 @@ handle_failed_stripe(struct r5conf *conf, struct stripe_head *sh,
                 bi = sh->dev[i].towrite;
                 sh->dev[i].towrite = NULL;
                 spin_unlock_irq(&sh->stripe_lock);
-                if (bi) {
-                        s->to_write--;
+                if (bi)
                         bitmap_end = 1;
-                }
 
                 if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
                         wake_up(&conf->wait_for_overlap);
@@ -2524,11 +2555,12 @@ handle_failed_stripe(struct r5conf *conf, struct stripe_head *sh,
                 if (!test_bit(R5_Wantfill, &sh->dev[i].flags) &&
                     (!test_bit(R5_Insync, &sh->dev[i].flags) ||
                       test_bit(R5_ReadError, &sh->dev[i].flags))) {
+                        spin_lock_irq(&sh->stripe_lock);
                         bi = sh->dev[i].toread;
                         sh->dev[i].toread = NULL;
+                        spin_unlock_irq(&sh->stripe_lock);
                         if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
                                 wake_up(&conf->wait_for_overlap);
-                        if (bi) s->to_read--;
                         while (bi && bi->bi_sector <
                                sh->dev[i].sector + STRIPE_SECTORS) {
                                 struct bio *nextbi =
@@ -2741,7 +2773,8 @@ static void handle_stripe_clean_event(struct r5conf *conf,
                 if (sh->dev[i].written) {
                         dev = &sh->dev[i];
                         if (!test_bit(R5_LOCKED, &dev->flags) &&
-                                test_bit(R5_UPTODATE, &dev->flags)) {
+                            (test_bit(R5_UPTODATE, &dev->flags) ||
+                             test_and_clear_bit(R5_Discard, &dev->flags))) {
                                 /* We can return any write requests */
                                 struct bio *wbi, *wbi2;
                                 pr_debug("Return write for disc %d\n", i);
@@ -2775,12 +2808,25 @@ static void handle_stripe_dirtying(struct r5conf *conf,
                                    int disks)
 {
         int rmw = 0, rcw = 0, i;
-        if (conf->max_degraded == 2) {
-                /* RAID6 requires 'rcw' in current implementation
-                 * Calculate the real rcw later - for now fake it
+        sector_t recovery_cp = conf->mddev->recovery_cp;
+
+        /* RAID6 requires 'rcw' in current implementation.
+         * Otherwise, check whether resync is now happening or should start.
+         * If yes, then the array is dirty (after unclean shutdown or
+         * initial creation), so parity in some stripes might be inconsistent.
+         * In this case, we need to always do reconstruct-write, to ensure
+         * that in case of drive failure or read-error correction, we
+         * generate correct data from the parity.
+         */
+        if (conf->max_degraded == 2 ||
+            (recovery_cp < MaxSector && sh->sector >= recovery_cp)) {
+                /* Calculate the real rcw later - for now make it
                  * look like rcw is cheaper
                  */
                 rcw = 1; rmw = 2;
+                pr_debug("force RCW max_degraded=%u, recovery_cp=%llu sh->sector=%llu\n",
+                         conf->max_degraded, (unsigned long long)recovery_cp,
+                         (unsigned long long)sh->sector);
         } else for (i = disks; i--; ) {
                 /* would I have to read this buffer for read_modify_write */
                 struct r5dev *dev = &sh->dev[i];
@@ -2932,7 +2978,7 @@ static void handle_parity_checks5(struct r5conf *conf, struct stripe_head *sh,
                          */
                         set_bit(STRIPE_INSYNC, &sh->state);
                 else {
-                        conf->mddev->resync_mismatches += STRIPE_SECTORS;
+                        atomic64_add(STRIPE_SECTORS, &conf->mddev->resync_mismatches);
                         if (test_bit(MD_RECOVERY_CHECK, &conf->mddev->recovery))
                                 /* don't try to repair!! */
                                 set_bit(STRIPE_INSYNC, &sh->state);
@@ -3084,7 +3130,7 @@ static void handle_parity_checks6(struct r5conf *conf, struct stripe_head *sh,
                                  */
                         }
                 } else {
-                        conf->mddev->resync_mismatches += STRIPE_SECTORS;
+                        atomic64_add(STRIPE_SECTORS, &conf->mddev->resync_mismatches);
                         if (test_bit(MD_RECOVERY_CHECK, &conf->mddev->recovery))
                                 /* don't try to repair!! */
                                 set_bit(STRIPE_INSYNC, &sh->state);
@@ -3459,10 +3505,12 @@ static void handle_stripe(struct stripe_head *sh)
         if (s.written &&
             (s.p_failed || ((test_bit(R5_Insync, &pdev->flags)
                              && !test_bit(R5_LOCKED, &pdev->flags)
-                             && test_bit(R5_UPTODATE, &pdev->flags)))) &&
+                             && (test_bit(R5_UPTODATE, &pdev->flags) ||
+                                 test_bit(R5_Discard, &pdev->flags))))) &&
             (s.q_failed || ((test_bit(R5_Insync, &qdev->flags)
                              && !test_bit(R5_LOCKED, &qdev->flags)
-                             && test_bit(R5_UPTODATE, &qdev->flags)))))
+                             && (test_bit(R5_UPTODATE, &qdev->flags) ||
+                                 test_bit(R5_Discard, &qdev->flags))))))
                 handle_stripe_clean_event(conf, sh, disks, &s.return_bi);
 
         /* Now we might consider reading some blocks, either to check/generate
@@ -3489,9 +3537,11 @@ static void handle_stripe(struct stripe_head *sh)
                 /* All the 'written' buffers and the parity block are ready to
                  * be written back to disk
                  */
-                BUG_ON(!test_bit(R5_UPTODATE, &sh->dev[sh->pd_idx].flags));
+                BUG_ON(!test_bit(R5_UPTODATE, &sh->dev[sh->pd_idx].flags) &&
+                       !test_bit(R5_Discard, &sh->dev[sh->pd_idx].flags));
                 BUG_ON(sh->qd_idx >= 0 &&
-                       !test_bit(R5_UPTODATE, &sh->dev[sh->qd_idx].flags));
+                       !test_bit(R5_UPTODATE, &sh->dev[sh->qd_idx].flags) &&
+                       !test_bit(R5_Discard, &sh->dev[sh->qd_idx].flags));
                 for (i = disks; i--; ) {
                         struct r5dev *dev = &sh->dev[i];
                         if (test_bit(R5_LOCKED, &dev->flags) &&
@@ -4072,6 +4122,88 @@ static void release_stripe_plug(struct mddev *mddev,
                 release_stripe(sh);
 }
 
+static void make_discard_request(struct mddev *mddev, struct bio *bi)
+{
+        struct r5conf *conf = mddev->private;
+        sector_t logical_sector, last_sector;
+        struct stripe_head *sh;
+        int remaining;
+        int stripe_sectors;
+
+        if (mddev->reshape_position != MaxSector)
+                /* Skip discard while reshape is happening */
+                return;
+
+        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 */
+
+        stripe_sectors = conf->chunk_sectors *
+                (conf->raid_disks - conf->max_degraded);
+        logical_sector = DIV_ROUND_UP_SECTOR_T(logical_sector,
+                                               stripe_sectors);
+        sector_div(last_sector, stripe_sectors);
+
+        logical_sector *= conf->chunk_sectors;
+        last_sector *= conf->chunk_sectors;
+
+        for (; logical_sector < last_sector;
+             logical_sector += STRIPE_SECTORS) {
+                DEFINE_WAIT(w);
+                int d;
+        again:
+                sh = get_active_stripe(conf, logical_sector, 0, 0, 0);
+                prepare_to_wait(&conf->wait_for_overlap, &w,
+                                TASK_UNINTERRUPTIBLE);
+                spin_lock_irq(&sh->stripe_lock);
+                for (d = 0; d < conf->raid_disks; d++) {
+                        if (d == sh->pd_idx || d == sh->qd_idx)
+                                continue;
+                        if (sh->dev[d].towrite || sh->dev[d].toread) {
+                                set_bit(R5_Overlap, &sh->dev[d].flags);
+                                spin_unlock_irq(&sh->stripe_lock);
+                                release_stripe(sh);
+                                schedule();
+                                goto again;
+                        }
+                }
+                finish_wait(&conf->wait_for_overlap, &w);
+                for (d = 0; d < conf->raid_disks; d++) {
+                        if (d == sh->pd_idx || d == sh->qd_idx)
+                                continue;
+                        sh->dev[d].towrite = bi;
+                        set_bit(R5_OVERWRITE, &sh->dev[d].flags);
+                        raid5_inc_bi_active_stripes(bi);
+                }
+                spin_unlock_irq(&sh->stripe_lock);
+                if (conf->mddev->bitmap) {
+                        for (d = 0;
+                             d < conf->raid_disks - conf->max_degraded;
+                             d++)
+                                bitmap_startwrite(mddev->bitmap,
+                                                  sh->sector,
+                                                  STRIPE_SECTORS,
+                                                  0);
+                        sh->bm_seq = conf->seq_flush + 1;
+                        set_bit(STRIPE_BIT_DELAY, &sh->state);
+                }
+
+                set_bit(STRIPE_HANDLE, &sh->state);
+                clear_bit(STRIPE_DELAYED, &sh->state);
+                if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
+                        atomic_inc(&conf->preread_active_stripes);
+                release_stripe_plug(mddev, sh);
+        }
+
+        remaining = raid5_dec_bi_active_stripes(bi);
+        if (remaining == 0) {
+                md_write_end(mddev);
+                bio_endio(bi, 0);
+        }
+}
+
 static void make_request(struct mddev *mddev, struct bio * bi)
 {
         struct r5conf *conf = mddev->private;
@@ -4094,6 +4226,11 @@ static void make_request(struct mddev *mddev, struct bio * bi)
              chunk_aligned_read(mddev,bi))
                 return;
 
+        if (unlikely(bi->bi_rw & REQ_DISCARD)) {
+                make_discard_request(mddev, bi);
+                return;
+        }
+
         logical_sector = bi->bi_sector & ~((sector_t)STRIPE_SECTORS-1);
         last_sector = bi->bi_sector + (bi->bi_size>>9);
         bi->bi_next = NULL;
@@ -4630,8 +4767,9 @@ static int handle_active_stripes(struct r5conf *conf)
  * During the scan, completed stripes are saved for us by the interrupt
  * handler, so that they will not have to wait for our next wakeup.
  */
-static void raid5d(struct mddev *mddev)
+static void raid5d(struct md_thread *thread)
 {
+        struct mddev *mddev = thread->mddev;
         struct r5conf *conf = mddev->private;
         int handled;
         struct blk_plug plug;
@@ -5366,6 +5504,7 @@ static int run(struct mddev *mddev)
 
         if (mddev->queue) {
                 int chunk_size;
+                bool discard_supported = true;
                 /* read-ahead size must cover two whole stripes, which
                  * is 2 * (datadisks) * chunksize where 'n' is the
                  * number of raid devices
@@ -5385,13 +5524,48 @@ static int run(struct mddev *mddev)
                 blk_queue_io_min(mddev->queue, chunk_size);
                 blk_queue_io_opt(mddev->queue, chunk_size *
                                  (conf->raid_disks - conf->max_degraded));
+                /*
+                 * We can only discard a whole stripe. It doesn't make sense to
+                 * discard data disk but write parity disk
+                 */
+                stripe = stripe * PAGE_SIZE;
+                mddev->queue->limits.discard_alignment = stripe;
+                mddev->queue->limits.discard_granularity = stripe;
+                /*
+                 * unaligned part of discard request will be ignored, so can't
+                 * guarantee discard_zerors_data
+                 */
+                mddev->queue->limits.discard_zeroes_data = 0;
 
                 rdev_for_each(rdev, mddev) {
                         disk_stack_limits(mddev->gendisk, rdev->bdev,
                                           rdev->data_offset << 9);
                         disk_stack_limits(mddev->gendisk, rdev->bdev,
                                           rdev->new_data_offset << 9);
+                        /*
+                         * discard_zeroes_data is required, otherwise data
+                         * could be lost. Consider a scenario: discard a stripe
+                         * (the stripe could be inconsistent if
+                         * discard_zeroes_data is 0); write one disk of the
+                         * stripe (the stripe could be inconsistent again
+                         * depending on which disks are used to calculate
+                         * parity); the disk is broken; The stripe data of this
+                         * disk is lost.
+                         */
+                        if (!blk_queue_discard(bdev_get_queue(rdev->bdev)) ||
+                            !bdev_get_queue(rdev->bdev)->
+                                                limits.discard_zeroes_data)
+                                discard_supported = false;
                 }
+
+                if (discard_supported &&
+                   mddev->queue->limits.max_discard_sectors >= stripe &&
+                   mddev->queue->limits.discard_granularity >= stripe)
+                        queue_flag_set_unlocked(QUEUE_FLAG_DISCARD,
+                                                mddev->queue);
+                else
+                        queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD,
+                                                mddev->queue);
         }
 
         return 0;
@@ -5702,7 +5876,8 @@ static int check_reshape(struct mddev *mddev)
         if (!check_stripe_cache(mddev))
                 return -ENOSPC;
 
-        return resize_stripes(conf, conf->raid_disks + mddev->delta_disks);
+        return resize_stripes(conf, (conf->previous_raid_disks
+                                     + mddev->delta_disks));
 }
 
 static int raid5_start_reshape(struct mddev *mddev)