btrfs: btrfs_multi_bio replaced with btrfs_bio

btrfs_bio is a bio abstraction able to split and not complete after the last
bio has returned (like the old btrfs_multi_bio). Additionally, btrfs_bio
tracks the mirror_num used to read data which can be used for error
correction purposes.

Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net>

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index f5be06a..119f842 100644 (file)
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -1770,18 +1770,18 @@ static int btrfs_discard_extent(struct btrfs_root *root, u64 bytenr,
 {
        int ret;
        u64 discarded_bytes = 0;
-       struct btrfs_multi_bio *multi = NULL;
+       struct btrfs_bio *bbio = NULL;
 
 
        /* Tell the block device(s) that the sectors can be discarded */
        ret = btrfs_map_block(&root->fs_info->mapping_tree, REQ_DISCARD,
-                             bytenr, &num_bytes, &multi, 0);
+                             bytenr, &num_bytes, &bbio, 0);
        if (!ret) {
-               struct btrfs_bio_stripe *stripe = multi->stripes;
+               struct btrfs_bio_stripe *stripe = bbio->stripes;
                int i;
 
 
-               for (i = 0; i < multi->num_stripes; i++, stripe++) {
+               for (i = 0; i < bbio->num_stripes; i++, stripe++) {
                        if (!stripe->dev->can_discard)
                                continue;
 
@@ -1800,7 +1800,7 @@ static int btrfs_discard_extent(struct btrfs_root *root, u64 bytenr,
                         */
                        ret = 0;
                }
-               kfree(multi);
+               kfree(bbio);
        }
 
        if (actual_bytes)

diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c
index db09f01..97142a2 100644 (file)
--- a/fs/btrfs/scrub.c
+++ b/fs/btrfs/scrub.c
@@ -572,7 +572,7 @@ static void scrub_fixup(struct scrub_bio *sbio, int ix)
        struct scrub_dev *sdev = sbio->sdev;
        struct btrfs_fs_info *fs_info = sdev->dev->dev_root->fs_info;
        struct btrfs_mapping_tree *map_tree = &fs_info->mapping_tree;
-       struct btrfs_multi_bio *multi = NULL;
+       struct btrfs_bio *bbio = NULL;
        struct scrub_fixup_nodatasum *fixup;
        u64 logical = sbio->logical + ix * PAGE_SIZE;
        u64 length;
@@ -610,8 +610,8 @@ static void scrub_fixup(struct scrub_bio *sbio, int ix)
 
        length = PAGE_SIZE;
        ret = btrfs_map_block(map_tree, REQ_WRITE, logical, &length,
-                             &multi, 0);
-       if (ret || !multi || length < PAGE_SIZE) {
+                             &bbio, 0);
+       if (ret || !bbio || length < PAGE_SIZE) {
                printk(KERN_ERR
                       "scrub_fixup: btrfs_map_block failed us for %llu\n",
                       (unsigned long long)logical);
@@ -619,19 +619,19 @@ static void scrub_fixup(struct scrub_bio *sbio, int ix)
                return;
        }
 
-       if (multi->num_stripes == 1)
+       if (bbio->num_stripes == 1)
                /* there aren't any replicas */
                goto uncorrectable;
 
        /*
         * first find a good copy
         */
-       for (i = 0; i < multi->num_stripes; ++i) {
+       for (i = 0; i < bbio->num_stripes; ++i) {
                if (i + 1 == sbio->spag[ix].mirror_num)
                        continue;
 
-               if (scrub_fixup_io(READ, multi->stripes[i].dev->bdev,
-                                  multi->stripes[i].physical >> 9,
+               if (scrub_fixup_io(READ, bbio->stripes[i].dev->bdev,
+                                  bbio->stripes[i].physical >> 9,
                                   sbio->bio->bi_io_vec[ix].bv_page)) {
                        /* I/O-error, this is not a good copy */
                        continue;
@@ -640,7 +640,7 @@ static void scrub_fixup(struct scrub_bio *sbio, int ix)
                if (scrub_fixup_check(sbio, ix) == 0)
                        break;
        }
-       if (i == multi->num_stripes)
+       if (i == bbio->num_stripes)
                goto uncorrectable;
 
        if (!sdev->readonly) {
@@ -655,7 +655,7 @@ static void scrub_fixup(struct scrub_bio *sbio, int ix)
                }
        }
 
-       kfree(multi);
+       kfree(bbio);
        spin_lock(&sdev->stat_lock);
        ++sdev->stat.corrected_errors;
        spin_unlock(&sdev->stat_lock);
@@ -665,7 +665,7 @@ static void scrub_fixup(struct scrub_bio *sbio, int ix)
        return;
 
 uncorrectable:
-       kfree(multi);
+       kfree(bbio);
        spin_lock(&sdev->stat_lock);
        ++sdev->stat.uncorrectable_errors;
        spin_unlock(&sdev->stat_lock);

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index f2a4cc7..9db4d79 100644 (file)
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -2848,7 +2848,7 @@ static int find_live_mirror(struct map_lookup *map, int first, int num,
 
 static int __btrfs_map_block(struct btrfs_mapping_tree *map_tree, int rw,
                             u64 logical, u64 *length,
-                            struct btrfs_multi_bio **multi_ret,
+                            struct btrfs_bio **bbio_ret,
                             int mirror_num)
 {
        struct extent_map *em;
@@ -2866,18 +2866,18 @@ static int __btrfs_map_block(struct btrfs_mapping_tree *map_tree, int rw,
        int i;
        int num_stripes;
        int max_errors = 0;
-       struct btrfs_multi_bio *multi = NULL;
+       struct btrfs_bio *bbio = NULL;
 
-       if (multi_ret && !(rw & (REQ_WRITE | REQ_DISCARD)))
+       if (bbio_ret && !(rw & (REQ_WRITE | REQ_DISCARD)))
                stripes_allocated = 1;
 again:
-       if (multi_ret) {
-               multi = kzalloc(btrfs_multi_bio_size(stripes_allocated),
+       if (bbio_ret) {
+               bbio = kzalloc(btrfs_bio_size(stripes_allocated),
                                GFP_NOFS);
-               if (!multi)
+               if (!bbio)
                        return -ENOMEM;
 
-               atomic_set(&multi->error, 0);
+               atomic_set(&bbio->error, 0);
        }
 
        read_lock(&em_tree->lock);
@@ -2898,7 +2898,7 @@ again:
        if (mirror_num > map->num_stripes)
                mirror_num = 0;
 
-       /* if our multi bio struct is too small, back off and try again */
+       /* if our btrfs_bio struct is too small, back off and try again */
        if (rw & REQ_WRITE) {
                if (map->type & (BTRFS_BLOCK_GROUP_RAID1 |
                                 BTRFS_BLOCK_GROUP_DUP)) {
@@ -2917,11 +2917,11 @@ again:
                        stripes_required = map->num_stripes;
                }
        }
-       if (multi_ret && (rw & (REQ_WRITE | REQ_DISCARD)) &&
+       if (bbio_ret && (rw & (REQ_WRITE | REQ_DISCARD)) &&
            stripes_allocated < stripes_required) {
                stripes_allocated = map->num_stripes;
                free_extent_map(em);
-               kfree(multi);
+               kfree(bbio);
                goto again;
        }
        stripe_nr = offset;
@@ -2950,7 +2950,7 @@ again:
                *length = em->len - offset;
        }
 
-       if (!multi_ret)
+       if (!bbio_ret)
                goto out;
 
        num_stripes = 1;
@@ -2975,13 +2975,17 @@ again:
                        stripe_index = find_live_mirror(map, 0,
                                            map->num_stripes,
                                            current->pid % map->num_stripes);
+                       mirror_num = stripe_index + 1;
                }
 
        } else if (map->type & BTRFS_BLOCK_GROUP_DUP) {
-               if (rw & (REQ_WRITE | REQ_DISCARD))
+               if (rw & (REQ_WRITE | REQ_DISCARD)) {
                        num_stripes = map->num_stripes;
-               else if (mirror_num)
+               } else if (mirror_num) {
                        stripe_index = mirror_num - 1;
+               } else {
+                       mirror_num = 1;
+               }
 
        } else if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
                int factor = map->num_stripes / map->sub_stripes;
@@ -3001,6 +3005,7 @@ again:
                        stripe_index = find_live_mirror(map, stripe_index,
                                              map->sub_stripes, stripe_index +
                                              current->pid % map->sub_stripes);
+                       mirror_num = stripe_index + 1;
                }
        } else {
                /*
@@ -3009,15 +3014,16 @@ again:
                 * stripe_index is the number of our device in the stripe array
                 */
                stripe_index = do_div(stripe_nr, map->num_stripes);
+               mirror_num = stripe_index + 1;
        }
        BUG_ON(stripe_index >= map->num_stripes);
 
        if (rw & REQ_DISCARD) {
                for (i = 0; i < num_stripes; i++) {
-                       multi->stripes[i].physical =
+                       bbio->stripes[i].physical =
                                map->stripes[stripe_index].physical +
                                stripe_offset + stripe_nr * map->stripe_len;
-                       multi->stripes[i].dev = map->stripes[stripe_index].dev;
+                       bbio->stripes[i].dev = map->stripes[stripe_index].dev;
 
                        if (map->type & BTRFS_BLOCK_GROUP_RAID0) {
                                u64 stripes;
@@ -3038,16 +3044,16 @@ again:
                                }
                                stripes = stripe_nr_end - 1 - j;
                                do_div(stripes, map->num_stripes);
-                               multi->stripes[i].length = map->stripe_len *
+                               bbio->stripes[i].length = map->stripe_len *
                                        (stripes - stripe_nr + 1);
 
                                if (i == 0) {
-                                       multi->stripes[i].length -=
+                                       bbio->stripes[i].length -=
                                                stripe_offset;
                                        stripe_offset = 0;
                                }
                                if (stripe_index == last_stripe)
-                                       multi->stripes[i].length -=
+                                       bbio->stripes[i].length -=
                                                stripe_end_offset;
                        } else if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
                                u64 stripes;
@@ -3072,11 +3078,11 @@ again:
                                }
                                stripes = stripe_nr_end - 1 - j;
                                do_div(stripes, factor);
-                               multi->stripes[i].length = map->stripe_len *
+                               bbio->stripes[i].length = map->stripe_len *
                                        (stripes - stripe_nr + 1);
 
                                if (i < map->sub_stripes) {
-                                       multi->stripes[i].length -=
+                                       bbio->stripes[i].length -=
                                                stripe_offset;
                                        if (i == map->sub_stripes - 1)
                                                stripe_offset = 0;
@@ -3084,11 +3090,11 @@ again:
                                if (stripe_index >= last_stripe &&
                                    stripe_index <= (last_stripe +
                                                     map->sub_stripes - 1)) {
-                                       multi->stripes[i].length -=
+                                       bbio->stripes[i].length -=
                                                stripe_end_offset;
                                }
                        } else
-                               multi->stripes[i].length = *length;
+                               bbio->stripes[i].length = *length;
 
                        stripe_index++;
                        if (stripe_index == map->num_stripes) {
@@ -3099,19 +3105,20 @@ again:
                }
        } else {
                for (i = 0; i < num_stripes; i++) {
-                       multi->stripes[i].physical =
+                       bbio->stripes[i].physical =
                                map->stripes[stripe_index].physical +
                                stripe_offset +
                                stripe_nr * map->stripe_len;
-                       multi->stripes[i].dev =
+                       bbio->stripes[i].dev =
                                map->stripes[stripe_index].dev;
                        stripe_index++;
                }
        }
-       if (multi_ret) {
-               *multi_ret = multi;
-               multi->num_stripes = num_stripes;
-               multi->max_errors = max_errors;
+       if (bbio_ret) {
+               *bbio_ret = bbio;
+               bbio->num_stripes = num_stripes;
+               bbio->max_errors = max_errors;
+               bbio->mirror_num = mirror_num;
        }
 out:
        free_extent_map(em);
@@ -3120,9 +3127,9 @@ out:
 
 int btrfs_map_block(struct btrfs_mapping_tree *map_tree, int rw,
                      u64 logical, u64 *length,
-                     struct btrfs_multi_bio **multi_ret, int mirror_num)
+                     struct btrfs_bio **bbio_ret, int mirror_num)
 {
-       return __btrfs_map_block(map_tree, rw, logical, length, multi_ret,
+       return __btrfs_map_block(map_tree, rw, logical, length, bbio_ret,
                                 mirror_num);
 }
 
@@ -3191,28 +3198,28 @@ int btrfs_rmap_block(struct btrfs_mapping_tree *map_tree,
        return 0;
 }
 
-static void end_bio_multi_stripe(struct bio *bio, int err)
+static void btrfs_end_bio(struct bio *bio, int err)
 {
-       struct btrfs_multi_bio *multi = bio->bi_private;
+       struct btrfs_bio *bbio = bio->bi_private;
        int is_orig_bio = 0;
 
        if (err)
-               atomic_inc(&multi->error);
+               atomic_inc(&bbio->error);
 
-       if (bio == multi->orig_bio)
+       if (bio == bbio->orig_bio)
                is_orig_bio = 1;
 
-       if (atomic_dec_and_test(&multi->stripes_pending)) {
+       if (atomic_dec_and_test(&bbio->stripes_pending)) {
                if (!is_orig_bio) {
                        bio_put(bio);
-                       bio = multi->orig_bio;
+                       bio = bbio->orig_bio;
                }
-               bio->bi_private = multi->private;
-               bio->bi_end_io = multi->end_io;
+               bio->bi_private = bbio->private;
+               bio->bi_end_io = bbio->end_io;
                /* only send an error to the higher layers if it is
                 * beyond the tolerance of the multi-bio
                 */
-               if (atomic_read(&multi->error) > multi->max_errors) {
+               if (atomic_read(&bbio->error) > bbio->max_errors) {
                        err = -EIO;
                } else if (err) {
                        /*
@@ -3222,7 +3229,7 @@ static void end_bio_multi_stripe(struct bio *bio, int err)
                        set_bit(BIO_UPTODATE, &bio->bi_flags);
                        err = 0;
                }
-               kfree(multi);
+               kfree(bbio);
 
                bio_endio(bio, err);
        } else if (!is_orig_bio) {
@@ -3302,20 +3309,20 @@ int btrfs_map_bio(struct btrfs_root *root, int rw, struct bio *bio,
        u64 logical = (u64)bio->bi_sector << 9;
        u64 length = 0;
        u64 map_length;
-       struct btrfs_multi_bio *multi = NULL;
        int ret;
        int dev_nr = 0;
        int total_devs = 1;
+       struct btrfs_bio *bbio = NULL;
 
        length = bio->bi_size;
        map_tree = &root->fs_info->mapping_tree;
        map_length = length;
 
-       ret = btrfs_map_block(map_tree, rw, logical, &map_length, &multi,
+       ret = btrfs_map_block(map_tree, rw, logical, &map_length, &bbio,
                              mirror_num);
        BUG_ON(ret);
 
-       total_devs = multi->num_stripes;
+       total_devs = bbio->num_stripes;
        if (map_length < length) {
                printk(KERN_CRIT "mapping failed logical %llu bio len %llu "
                       "len %llu\n", (unsigned long long)logical,
@@ -3323,25 +3330,28 @@ int btrfs_map_bio(struct btrfs_root *root, int rw, struct bio *bio,
                       (unsigned long long)map_length);
                BUG();
        }
-       multi->end_io = first_bio->bi_end_io;
-       multi->private = first_bio->bi_private;
-       multi->orig_bio = first_bio;
-       atomic_set(&multi->stripes_pending, multi->num_stripes);
+
+       bbio->orig_bio = first_bio;
+       bbio->private = first_bio->bi_private;
+       bbio->end_io = first_bio->bi_end_io;
+       atomic_set(&bbio->stripes_pending, bbio->num_stripes);
 
        while (dev_nr < total_devs) {
-               if (total_devs > 1) {
-                       if (dev_nr < total_devs - 1) {
-                               bio = bio_clone(first_bio, GFP_NOFS);
-                               BUG_ON(!bio);
-                       } else {
-                               bio = first_bio;
-                       }
-                       bio->bi_private = multi;
-                       bio->bi_end_io = end_bio_multi_stripe;
+               if (dev_nr < total_devs - 1) {
+                       bio = bio_clone(first_bio, GFP_NOFS);
+                       BUG_ON(!bio);
+               } else {
+                       bio = first_bio;
                }
-               bio->bi_sector = multi->stripes[dev_nr].physical >> 9;
-               dev = multi->stripes[dev_nr].dev;
+               bio->bi_private = bbio;
+               bio->bi_end_io = btrfs_end_bio;
+               bio->bi_sector = bbio->stripes[dev_nr].physical >> 9;
+               dev = bbio->stripes[dev_nr].dev;
                if (dev && dev->bdev && (rw != WRITE || dev->writeable)) {
+                       pr_debug("btrfs_map_bio: rw %d, secor=%llu, dev=%lu "
+                                "(%s id %llu), size=%u\n", rw,
+                                (u64)bio->bi_sector, (u_long)dev->bdev->bd_dev,
+                                dev->name, dev->devid, bio->bi_size);
                        bio->bi_bdev = dev->bdev;
                        if (async_submit)
                                schedule_bio(root, dev, rw, bio);
@@ -3354,8 +3364,6 @@ int btrfs_map_bio(struct btrfs_root *root, int rw, struct bio *bio,
                }
                dev_nr++;
        }
-       if (total_devs == 1)
-               kfree(multi);
        return 0;
 }
 

diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
index 6d866db..71f4f3f 100644 (file)
--- a/fs/btrfs/volumes.h
+++ b/fs/btrfs/volumes.h
@@ -136,7 +136,10 @@ struct btrfs_bio_stripe {
        u64 length; /* only used for discard mappings */
 };
 
-struct btrfs_multi_bio {
+struct btrfs_bio;
+typedef void (btrfs_bio_end_io_t) (struct btrfs_bio *bio, int err);
+
+struct btrfs_bio {
        atomic_t stripes_pending;
        bio_end_io_t *end_io;
        struct bio *orig_bio;
@@ -144,6 +147,7 @@ struct btrfs_multi_bio {
        atomic_t error;
        int max_errors;
        int num_stripes;
+       int mirror_num;
        struct btrfs_bio_stripe stripes[];
 };
 
@@ -171,7 +175,7 @@ struct map_lookup {
 int btrfs_account_dev_extents_size(struct btrfs_device *device, u64 start,
                                   u64 end, u64 *length);
 
-#define btrfs_multi_bio_size(n) (sizeof(struct btrfs_multi_bio) + \
+#define btrfs_bio_size(n) (sizeof(struct btrfs_bio) + \
                            (sizeof(struct btrfs_bio_stripe) * (n)))
 
 int btrfs_alloc_dev_extent(struct btrfs_trans_handle *trans,
@@ -180,7 +184,7 @@ int btrfs_alloc_dev_extent(struct btrfs_trans_handle *trans,
                           u64 chunk_offset, u64 start, u64 num_bytes);
 int btrfs_map_block(struct btrfs_mapping_tree *map_tree, int rw,
                    u64 logical, u64 *length,
-                   struct btrfs_multi_bio **multi_ret, int mirror_num);
+                   struct btrfs_bio **bbio_ret, int mirror_num);
 int btrfs_rmap_block(struct btrfs_mapping_tree *map_tree,
                     u64 chunk_start, u64 physical, u64 devid,
                     u64 **logical, int *naddrs, int *stripe_len);