From 8790d502e4401a4a3a4175b83a3a47e8d595c771 Mon Sep 17 00:00:00 2001 From: Chris Mason Date: Thu, 3 Apr 2008 16:29:03 -0400 Subject: Btrfs: Add support for mirroring across drives Signed-off-by: Chris Mason --- fs/btrfs/volumes.c | 154 +++++++++++++++++++++++++++++++++++++++++++---------- 1 file changed, 126 insertions(+), 28 deletions(-) (limited to 'fs/btrfs/volumes.c') diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index 169be0f7285..bc3c0b97588 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -31,6 +31,13 @@ struct stripe { u64 physical; }; +struct multi_bio { + atomic_t stripes; + bio_end_io_t *end_io; + void *private; + int error; +}; + struct map_lookup { u64 type; int io_align; @@ -632,12 +639,12 @@ int btrfs_alloc_chunk(struct btrfs_trans_handle *trans, if (list_empty(dev_list)) return -ENOSPC; - if (type & BTRFS_BLOCK_GROUP_RAID0) + if (type & (BTRFS_BLOCK_GROUP_RAID0)) num_stripes = btrfs_super_num_devices(&info->super_copy); - if (type & BTRFS_BLOCK_GROUP_DATA) - stripe_len = 64 * 1024; - if (type & (BTRFS_BLOCK_GROUP_METADATA | BTRFS_BLOCK_GROUP_SYSTEM)) - stripe_len = 32 * 1024; + if (type & (BTRFS_BLOCK_GROUP_RAID1)) { + num_stripes = min_t(u64, 2, + btrfs_super_num_devices(&info->super_copy)); + } again: INIT_LIST_HEAD(&private_devs); cur = dev_list->next; @@ -682,7 +689,11 @@ again: stripes = &chunk->stripe; - *num_bytes = calc_size * num_stripes; + if (type & BTRFS_BLOCK_GROUP_RAID1) + *num_bytes = calc_size; + else + *num_bytes = calc_size * num_stripes; + index = 0; while(index < num_stripes) { BUG_ON(list_empty(&private_devs)); @@ -694,7 +705,7 @@ again: key.objectid, calc_size, &dev_offset); BUG_ON(ret); -printk("alloc chunk size %Lu from dev %Lu\n", calc_size, device->devid); +printk("alloc chunk start %Lu size %Lu from dev %Lu type %Lu\n", key.objectid, calc_size, device->devid, type); device->bytes_used += calc_size; ret = btrfs_update_device(trans, device); BUG_ON(ret); @@ -774,9 +785,9 @@ void btrfs_mapping_tree_free(struct btrfs_mapping_tree *tree) } } -int btrfs_map_block(struct btrfs_mapping_tree *map_tree, - u64 logical, u64 *phys, u64 *length, - struct btrfs_device **dev) +int btrfs_map_block(struct btrfs_mapping_tree *map_tree, int rw, + int dev_nr, u64 logical, u64 *phys, u64 *length, + struct btrfs_device **dev, int *total_devs) { struct extent_map *em; struct map_lookup *map; @@ -808,19 +819,39 @@ int btrfs_map_block(struct btrfs_mapping_tree *map_tree, /* stripe_offset is the offset of this block in its stripe*/ stripe_offset = offset - stripe_offset; - /* - * after this do_div call, stripe_nr is the number of stripes - * on this device we have to walk to find the data, and - * stripe_index is the number of our device in the stripe array - */ - stripe_index = do_div(stripe_nr, map->num_stripes); - + if (map->type & BTRFS_BLOCK_GROUP_RAID1) { + stripe_index = dev_nr; + if (rw & (1 << BIO_RW)) + *total_devs = map->num_stripes; + else { + int i; + u64 least = (u64)-1; + struct btrfs_device *cur; + + for (i = 0; i < map->num_stripes; i++) { + cur = map->stripes[i].dev; + spin_lock(&cur->io_lock); + if (cur->total_ios < least) { + least = cur->total_ios; + stripe_index = i; + } + spin_unlock(&cur->io_lock); + } + *total_devs = 1; + } + } else { + /* + * after this do_div call, stripe_nr is the number of stripes + * on this device we have to walk to find the data, and + * stripe_index is the number of our device in the stripe array + */ + stripe_index = do_div(stripe_nr, map->num_stripes); + } BUG_ON(stripe_index >= map->num_stripes); - *phys = map->stripes[stripe_index].physical + stripe_offset + stripe_nr * map->stripe_len; - if (map->type & BTRFS_BLOCK_GROUP_RAID0) { + if (map->type & (BTRFS_BLOCK_GROUP_RAID0 | BTRFS_BLOCK_GROUP_RAID1)) { /* we limit the length of each bio to what fits in a stripe */ *length = min_t(u64, em->len - offset, map->stripe_len - stripe_offset); @@ -833,33 +864,98 @@ int btrfs_map_block(struct btrfs_mapping_tree *map_tree, return 0; } +#if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,23) +static void end_bio_multi_stripe(struct bio *bio, int err) +#else +static int end_bio_multi_stripe(struct bio *bio, + unsigned int bytes_done, int err) +#endif +{ + struct multi_bio *multi = bio->bi_private; + +#if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,23) + if (bio->bi_size) + return 1; +#endif + if (err) + multi->error = err; + + if (atomic_dec_and_test(&multi->stripes)) { + bio->bi_private = multi->private; + bio->bi_end_io = multi->end_io; + + if (!err && multi->error) + err = multi->error; + kfree(multi); + + bio_endio(bio, err); + } else { + bio_put(bio); + } +#if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,23) + return 0; +#endif +} + int btrfs_map_bio(struct btrfs_root *root, int rw, struct bio *bio) { struct btrfs_mapping_tree *map_tree; struct btrfs_device *dev; + struct bio *first_bio = bio; u64 logical = bio->bi_sector << 9; u64 physical; u64 length = 0; u64 map_length; struct bio_vec *bvec; + struct multi_bio *multi = NULL; int i; int ret; + int dev_nr = 0; + int total_devs = 1; bio_for_each_segment(bvec, bio, i) { length += bvec->bv_len; } + map_tree = &root->fs_info->mapping_tree; map_length = length; - ret = btrfs_map_block(map_tree, logical, &physical, &map_length, &dev); - if (map_length < length) { - printk("mapping failed logical %Lu bio len %Lu physical %Lu " - "len %Lu\n", logical, length, physical, map_length); - BUG(); + while(dev_nr < total_devs) { + ret = btrfs_map_block(map_tree, rw, dev_nr, logical, + &physical, &map_length, &dev, + &total_devs); + if (map_length < length) { + printk("mapping failed logical %Lu bio len %Lu physical %Lu " + "len %Lu\n", logical, length, physical, map_length); + BUG(); + } + BUG_ON(map_length < length); + if (total_devs > 1) { + if (!multi) { + multi = kmalloc(sizeof(*multi), GFP_NOFS); + atomic_set(&multi->stripes, 1); + multi->end_io = bio->bi_end_io; + multi->private = first_bio->bi_private; + multi->error = 0; + } else { + atomic_inc(&multi->stripes); + } + 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; + } + bio->bi_sector = physical >> 9; + bio->bi_bdev = dev->bdev; + spin_lock(&dev->io_lock); + dev->total_ios++; + spin_unlock(&dev->io_lock); + submit_bio(rw, bio); + dev_nr++; } - BUG_ON(map_length < length); - bio->bi_sector = physical >> 9; - bio->bi_bdev = dev->bdev; - submit_bio(rw, bio); return 0; } @@ -982,6 +1078,8 @@ static int read_one_dev(struct btrfs_root *root, return -ENOMEM; list_add(&device->dev_list, &root->fs_info->fs_devices->devices); + device->total_ios = 0; + spin_lock_init(&device->io_lock); } fill_device_from_item(leaf, dev_item, device); -- cgit v1.2.3-70-g09d2