1 files changed, 79 insertions, 118 deletions

diff --git a/drivers/md/bcache/request.c b/drivers/md/bcache/request.c
index e5ff12e52d5b..786a1a4f74d8 100644
--- a/drivers/md/bcache/request.c
+++ b/drivers/md/bcache/request.c
@@ -10,6 +10,7 @@
 #include "btree.h"
 #include "debug.h"
 #include "request.h"
+#include "writeback.h"
 
 #include <linux/cgroup.h>
 #include <linux/module.h>
@@ -21,8 +22,6 @@
 
 #define CUTOFF_CACHE_ADD        95
 #define CUTOFF_CACHE_READA      90
-#define CUTOFF_WRITEBACK        50
-#define CUTOFF_WRITEBACK_SYNC   75
 
 struct kmem_cache *bch_search_cache;
 
@@ -489,6 +488,12 @@ static void bch_insert_data_loop(struct closure *cl)
                 bch_queue_gc(op->c);
         }
 
+        /*
+         * Journal writes are marked REQ_FLUSH; if the original write was a
+         * flush, it'll wait on the journal write.
+         */
+        bio->bi_rw &= ~(REQ_FLUSH|REQ_FUA);
+
         do {
                 unsigned i;
                 struct bkey *k;
@@ -510,10 +515,6 @@ static void bch_insert_data_loop(struct closure *cl)
                         goto err;
 
                 n = bch_bio_split(bio, KEY_SIZE(k), GFP_NOIO, split);
-                if (!n) {
-                        __bkey_put(op->c, k);
-                        continue_at(cl, bch_insert_data_loop, bcache_wq);
-                }
 
                 n->bi_end_io    = bch_insert_data_endio;
                 n->bi_private   = cl;
@@ -530,10 +531,9 @@ static void bch_insert_data_loop(struct closure *cl)
                 if (KEY_CSUM(k))
                         bio_csum(n, k);
 
-                pr_debug("%s", pkey(k));
+                trace_bcache_cache_insert(k);
                 bch_keylist_push(&op->keys);
 
-                trace_bcache_cache_insert(n, n->bi_sector, n->bi_bdev);
                 n->bi_rw |= REQ_WRITE;
                 bch_submit_bbio(n, op->c, k, 0);
         } while (n != bio);
@@ -716,7 +716,7 @@ static struct search *search_alloc(struct bio *bio, struct bcache_device *d)
         s->task                 = current;
         s->orig_bio             = bio;
         s->write                = (bio->bi_rw & REQ_WRITE) != 0;
-        s->op.flush_journal     = (bio->bi_rw & REQ_FLUSH) != 0;
+        s->op.flush_journal     = (bio->bi_rw & (REQ_FLUSH|REQ_FUA)) != 0;
         s->op.skip              = (bio->bi_rw & REQ_DISCARD) != 0;
         s->recoverable          = 1;
         s->start_time           = jiffies;
@@ -784,11 +784,8 @@ static void request_read_error(struct closure *cl)
         int i;
 
         if (s->recoverable) {
-                /* The cache read failed, but we can retry from the backing
-                 * device.
-                 */
-                pr_debug("recovering at sector %llu",
-                         (uint64_t) s->orig_bio->bi_sector);
+                /* Retry from the backing device: */
+                trace_bcache_read_retry(s->orig_bio);
 
                 s->error = 0;
                 bv = s->bio.bio.bi_io_vec;
@@ -806,7 +803,6 @@ static void request_read_error(struct closure *cl)
 
                 /* XXX: invalidate cache */
 
-                trace_bcache_read_retry(&s->bio.bio);
                 closure_bio_submit(&s->bio.bio, &s->cl, s->d);
         }
 
@@ -827,53 +823,13 @@ static void request_read_done(struct closure *cl)
          */
 
         if (s->op.cache_bio) {
-                struct bio_vec *src, *dst;
-                unsigned src_offset, dst_offset, bytes;
-                void *dst_ptr;
-
                 bio_reset(s->op.cache_bio);
                 s->op.cache_bio->bi_sector      = s->cache_miss->bi_sector;
                 s->op.cache_bio->bi_bdev        = s->cache_miss->bi_bdev;
                 s->op.cache_bio->bi_size        = s->cache_bio_sectors << 9;
                 bch_bio_map(s->op.cache_bio, NULL);
 
-                src = bio_iovec(s->op.cache_bio);
-                dst = bio_iovec(s->cache_miss);
-                src_offset = src->bv_offset;
-                dst_offset = dst->bv_offset;
-                dst_ptr = kmap(dst->bv_page);
-
-                while (1) {
-                        if (dst_offset == dst->bv_offset + dst->bv_len) {
-                                kunmap(dst->bv_page);
-                                dst++;
-                                if (dst == bio_iovec_idx(s->cache_miss,
-                                                s->cache_miss->bi_vcnt))
-                                        break;
-
-                                dst_offset = dst->bv_offset;
-                                dst_ptr = kmap(dst->bv_page);
-                        }
-
-                        if (src_offset == src->bv_offset + src->bv_len) {
-                                src++;
-                                if (src == bio_iovec_idx(s->op.cache_bio,
-                                                 s->op.cache_bio->bi_vcnt))
-                                        BUG();
-
-                                src_offset = src->bv_offset;
-                        }
-
-                        bytes = min(dst->bv_offset + dst->bv_len - dst_offset,
-                                    src->bv_offset + src->bv_len - src_offset);
-
-                        memcpy(dst_ptr + dst_offset,
-                               page_address(src->bv_page) + src_offset,
-                               bytes);
-
-                        src_offset      += bytes;
-                        dst_offset      += bytes;
-                }
+                bio_copy_data(s->cache_miss, s->op.cache_bio);
 
                 bio_put(s->cache_miss);
                 s->cache_miss = NULL;
@@ -899,6 +855,7 @@ static void request_read_done_bh(struct closure *cl)
         struct cached_dev *dc = container_of(s->d, struct cached_dev, disk);
 
         bch_mark_cache_accounting(s, !s->cache_miss, s->op.skip);
+        trace_bcache_read(s->orig_bio, !s->cache_miss, s->op.skip);
 
         if (s->error)
                 continue_at_nobarrier(cl, request_read_error, bcache_wq);
@@ -917,9 +874,6 @@ static int cached_dev_cache_miss(struct btree *b, struct search *s,
         struct bio *miss;
 
         miss = bch_bio_split(bio, sectors, GFP_NOIO, s->d->bio_split);
-        if (!miss)
-                return -EAGAIN;
-
         if (miss == bio)
                 s->op.lookup_done = true;
 
@@ -938,8 +892,9 @@ static int cached_dev_cache_miss(struct btree *b, struct search *s,
                 reada = min(dc->readahead >> 9,
                             sectors - bio_sectors(miss));
 
-                if (bio_end(miss) + reada > bdev_sectors(miss->bi_bdev))
-                        reada = bdev_sectors(miss->bi_bdev) - bio_end(miss);
+                if (bio_end_sector(miss) + reada > bdev_sectors(miss->bi_bdev))
+                        reada = bdev_sectors(miss->bi_bdev) -
+                                bio_end_sector(miss);
         }
 
         s->cache_bio_sectors = bio_sectors(miss) + reada;
@@ -963,13 +918,12 @@ static int cached_dev_cache_miss(struct btree *b, struct search *s,
                 goto out_put;
 
         bch_bio_map(s->op.cache_bio, NULL);
-        if (bch_bio_alloc_pages(s->op.cache_bio, __GFP_NOWARN|GFP_NOIO))
+        if (bio_alloc_pages(s->op.cache_bio, __GFP_NOWARN|GFP_NOIO))
                 goto out_put;
 
         s->cache_miss = miss;
         bio_get(s->op.cache_bio);
 
-        trace_bcache_cache_miss(s->orig_bio);
         closure_bio_submit(s->op.cache_bio, &s->cl, s->d);
 
         return ret;
@@ -1002,24 +956,13 @@ static void cached_dev_write_complete(struct closure *cl)
         cached_dev_bio_complete(cl);
 }
 
-static bool should_writeback(struct cached_dev *dc, struct bio *bio)
-{
-        unsigned threshold = (bio->bi_rw & REQ_SYNC)
-                ? CUTOFF_WRITEBACK_SYNC
-                : CUTOFF_WRITEBACK;
-
-        return !atomic_read(&dc->disk.detaching) &&
-                cache_mode(dc, bio) == CACHE_MODE_WRITEBACK &&
-                dc->disk.c->gc_stats.in_use < threshold;
-}
-
 static void request_write(struct cached_dev *dc, struct search *s)
 {
         struct closure *cl = &s->cl;
         struct bio *bio = &s->bio.bio;
         struct bkey start, end;
         start = KEY(dc->disk.id, bio->bi_sector, 0);
-        end = KEY(dc->disk.id, bio_end(bio), 0);
+        end = KEY(dc->disk.id, bio_end_sector(bio), 0);
 
         bch_keybuf_check_overlapping(&s->op.c->moving_gc_keys, &start, &end);
 
@@ -1034,22 +977,37 @@ static void request_write(struct cached_dev *dc, struct search *s)
         if (bio->bi_rw & REQ_DISCARD)
                 goto skip;
 
+        if (should_writeback(dc, s->orig_bio,
+                             cache_mode(dc, bio),
+                             s->op.skip)) {
+                s->op.skip = false;
+                s->writeback = true;
+        }
+
         if (s->op.skip)
                 goto skip;
 
-        if (should_writeback(dc, s->orig_bio))
-                s->writeback = true;
+        trace_bcache_write(s->orig_bio, s->writeback, s->op.skip);
 
         if (!s->writeback) {
                 s->op.cache_bio = bio_clone_bioset(bio, GFP_NOIO,
                                                    dc->disk.bio_split);
 
-                trace_bcache_writethrough(s->orig_bio);
                 closure_bio_submit(bio, cl, s->d);
         } else {
-                s->op.cache_bio = bio;
-                trace_bcache_writeback(s->orig_bio);
-                bch_writeback_add(dc, bio_sectors(bio));
+                bch_writeback_add(dc);
+
+                if (s->op.flush_journal) {
+                        /* Also need to send a flush to the backing device */
+                        s->op.cache_bio = bio_clone_bioset(bio, GFP_NOIO,
+                                                           dc->disk.bio_split);
+
+                        bio->bi_size = 0;
+                        bio->bi_vcnt = 0;
+                        closure_bio_submit(bio, cl, s->d);
+                } else {
+                        s->op.cache_bio = bio;
+                }
         }
 out:
         closure_call(&s->op.cl, bch_insert_data, NULL, cl);
@@ -1058,7 +1016,6 @@ skip:
         s->op.skip = true;
         s->op.cache_bio = s->orig_bio;
         bio_get(s->op.cache_bio);
-        trace_bcache_write_skip(s->orig_bio);
 
         if ((bio->bi_rw & REQ_DISCARD) &&
             !blk_queue_discard(bdev_get_queue(dc->bdev)))
@@ -1088,9 +1045,10 @@ static void request_nodata(struct cached_dev *dc, struct search *s)
 
 /* Cached devices - read & write stuff */
 
-int bch_get_congested(struct cache_set *c)
+unsigned bch_get_congested(struct cache_set *c)
 {
         int i;
+        long rand;
 
         if (!c->congested_read_threshold_us &&
             !c->congested_write_threshold_us)
@@ -1106,7 +1064,13 @@ int bch_get_congested(struct cache_set *c)
 
         i += CONGESTED_MAX;
 
-        return i <= 0 ? 1 : fract_exp_two(i, 6);
+        if (i > 0)
+                i = fract_exp_two(i, 6);
+
+        rand = get_random_int();
+        i -= bitmap_weight(&rand, BITS_PER_LONG);
+
+        return i > 0 ? i : 1;
 }
 
 static void add_sequential(struct task_struct *t)
@@ -1126,10 +1090,8 @@ static void check_should_skip(struct cached_dev *dc, struct search *s)
 {
         struct cache_set *c = s->op.c;
         struct bio *bio = &s->bio.bio;
-
-        long rand;
-        int cutoff = bch_get_congested(c);
         unsigned mode = cache_mode(dc, bio);
+        unsigned sectors, congested = bch_get_congested(c);
 
         if (atomic_read(&dc->disk.detaching) ||
             c->gc_stats.in_use > CUTOFF_CACHE_ADD ||
@@ -1147,17 +1109,14 @@ static void check_should_skip(struct cached_dev *dc, struct search *s)
                 goto skip;
         }
 
-        if (!cutoff) {
-                cutoff = dc->sequential_cutoff >> 9;
+        if (!congested && !dc->sequential_cutoff)
+                goto rescale;
 
-                if (!cutoff)
-                        goto rescale;
-
-                if (mode == CACHE_MODE_WRITEBACK &&
-                    (bio->bi_rw & REQ_WRITE) &&
-                    (bio->bi_rw & REQ_SYNC))
-                        goto rescale;
-        }
+        if (!congested &&
+            mode == CACHE_MODE_WRITEBACK &&
+            (bio->bi_rw & REQ_WRITE) &&
+            (bio->bi_rw & REQ_SYNC))
+                goto rescale;
 
         if (dc->sequential_merge) {
                 struct io *i;
@@ -1177,7 +1136,7 @@ found:
                 if (i->sequential + bio->bi_size > i->sequential)
                         i->sequential   += bio->bi_size;
 
-                i->last                  = bio_end(bio);
+                i->last                  = bio_end_sector(bio);
                 i->jiffies               = jiffies + msecs_to_jiffies(5000);
                 s->task->sequential_io   = i->sequential;
 
@@ -1192,12 +1151,19 @@ found:
                 add_sequential(s->task);
         }
 
-        rand = get_random_int();
-        cutoff -= bitmap_weight(&rand, BITS_PER_LONG);
+        sectors = max(s->task->sequential_io,
+                      s->task->sequential_io_avg) >> 9;
 
-        if (cutoff <= (int) (max(s->task->sequential_io,
-                                 s->task->sequential_io_avg) >> 9))
+        if (dc->sequential_cutoff &&
+            sectors >= dc->sequential_cutoff >> 9) {
+                trace_bcache_bypass_sequential(s->orig_bio);
                 goto skip;
+        }
+
+        if (congested && sectors >= congested) {
+                trace_bcache_bypass_congested(s->orig_bio);
+                goto skip;
+        }
 
 rescale:
         bch_rescale_priorities(c, bio_sectors(bio));
@@ -1288,30 +1254,25 @@ void bch_cached_dev_request_init(struct cached_dev *dc)
 static int flash_dev_cache_miss(struct btree *b, struct search *s,
                                 struct bio *bio, unsigned sectors)
 {
+        struct bio_vec *bv;
+        int i;
+
         /* Zero fill bio */
 
-        while (bio->bi_idx != bio->bi_vcnt) {
-                struct bio_vec *bv = bio_iovec(bio);
+        bio_for_each_segment(bv, bio, i) {
                 unsigned j = min(bv->bv_len >> 9, sectors);
 
                 void *p = kmap(bv->bv_page);
                 memset(p + bv->bv_offset, 0, j << 9);
                 kunmap(bv->bv_page);
 
-                bv->bv_len      -= j << 9;
-                bv->bv_offset   += j << 9;
-
-                if (bv->bv_len)
-                        return 0;
-
-                bio->bi_sector  += j;
-                bio->bi_size    -= j << 9;
-
-                bio->bi_idx++;
-                sectors         -= j;
+                sectors -= j;
         }
 
-        s->op.lookup_done = true;
+        bio_advance(bio, min(sectors << 9, bio->bi_size));
+
+        if (!bio->bi_size)
+                s->op.lookup_done = true;
 
         return 0;
 }
@@ -1338,8 +1299,8 @@ static void flash_dev_make_request(struct request_queue *q, struct bio *bio)
                 closure_call(&s->op.cl, btree_read_async, NULL, cl);
         } else if (bio_has_data(bio) || s->op.skip) {
                 bch_keybuf_check_overlapping(&s->op.c->moving_gc_keys,
-                                             &KEY(d->id, bio->bi_sector, 0),
-                                             &KEY(d->id, bio_end(bio), 0));
+                                        &KEY(d->id, bio->bi_sector, 0),
+                                        &KEY(d->id, bio_end_sector(bio), 0));
 
                 s->writeback    = true;
                 s->op.cache_bio = bio;