Turn off some commands in Makefile
[platform/upstream/btrfs-progs.git] / volumes.c
index a923388..4c29cef 100644 (file)
--- a/volumes.c
+++ b/volumes.c
@@ -91,7 +91,7 @@ static int device_list_add(const char *path,
 
        fs_devices = find_fsid(disk_super->fsid);
        if (!fs_devices) {
-               fs_devices = kmalloc(sizeof(*fs_devices), GFP_NOFS);
+               fs_devices = kzalloc(sizeof(*fs_devices), GFP_NOFS);
                if (!fs_devices)
                        return -ENOMEM;
                INIT_LIST_HEAD(&fs_devices->devices);
@@ -119,7 +119,15 @@ static int device_list_add(const char *path,
                        kfree(device);
                        return -ENOMEM;
                }
+               device->label = kstrdup(disk_super->label, GFP_NOFS);
+               device->total_devs = btrfs_super_num_devices(disk_super);
+               device->super_bytes_used = btrfs_super_bytes_used(disk_super);
+               device->total_bytes =
+                       btrfs_stack_device_total_bytes(&disk_super->dev_item);
+               device->bytes_used =
+                       btrfs_stack_device_bytes_used(&disk_super->dev_item);
                list_add(&device->dev_list, &fs_devices->devices);
+               device->fs_devices = fs_devices;
        }
 
        if (found_transid > fs_devices->latest_trans) {
@@ -128,7 +136,6 @@ static int device_list_add(const char *path,
        }
        if (fs_devices->lowest_devid > devid) {
                fs_devices->lowest_devid = devid;
-               printk("lowest devid now %llu\n", (unsigned long long)devid);
        }
        *fs_devices_ret = fs_devices;
        return 0;
@@ -136,14 +143,24 @@ static int device_list_add(const char *path,
 
 int btrfs_close_devices(struct btrfs_fs_devices *fs_devices)
 {
-       struct list_head *head = &fs_devices->devices;
+       struct btrfs_fs_devices *seed_devices;
        struct list_head *cur;
        struct btrfs_device *device;
-
-       list_for_each(cur, head) {
+again:
+       list_for_each(cur, &fs_devices->devices) {
                device = list_entry(cur, struct btrfs_device, dev_list);
-               device->fd = 0;
+               close(device->fd);
+               device->fd = -1;
+               device->writeable = 0;
+       }
+
+       seed_devices = fs_devices->seed;
+       fs_devices->seed = NULL;
+       if (seed_devices) {
+               fs_devices = seed_devices;
+               goto again;
        }
+
        return 0;
 }
 
@@ -157,18 +174,20 @@ int btrfs_open_devices(struct btrfs_fs_devices *fs_devices, int flags)
 
        list_for_each(cur, head) {
                device = list_entry(cur, struct btrfs_device, dev_list);
+
                fd = open(device->name, flags);
-printk("opening %s devid %llu fd %d\n", device->name,
-       (unsigned long long)device->devid, fd);
                if (fd < 0) {
                        ret = -errno;
                        goto fail;
                }
+
                if (device->devid == fs_devices->latest_devid)
                        fs_devices->latest_bdev = fd;
                if (device->devid == fs_devices->lowest_devid)
                        fs_devices->lowest_bdev = fd;
                device->fd = fd;
+               if (flags == O_RDWR)
+                       device->writeable = 1;
        }
        return 0;
 fail:
@@ -184,26 +203,26 @@ int btrfs_scan_one_device(int fd, const char *path,
        char *buf;
        int ret;
        u64 devid;
+       char uuidbuf[37];
 
        buf = malloc(4096);
        if (!buf) {
                ret = -ENOMEM;
                goto error;
        }
-       ret = pread(fd, buf, 4096, super_offset);
-       if (ret != 4096) {
-               ret = -EIO;
-               goto error;
-       }
        disk_super = (struct btrfs_super_block *)buf;
-       if (strncmp((char *)(&disk_super->magic), BTRFS_MAGIC,
-           sizeof(disk_super->magic))) {
-               ret = -ENOENT;
+       ret = btrfs_read_dev_super(fd, disk_super, super_offset);
+       if (ret < 0) {
+               ret = -EIO;
                goto error_brelse;
        }
        devid = le64_to_cpu(disk_super->dev_item.devid);
-       *total_devs = btrfs_super_num_devices(disk_super);
-       printk("found device %llu on %s\n", (unsigned long long)devid, path);
+       if (btrfs_super_flags(disk_super) & BTRFS_SUPER_FLAG_METADUMP)
+               *total_devs = 1;
+       else
+               *total_devs = btrfs_super_num_devices(disk_super);
+       uuid_unparse(disk_super->fsid, uuidbuf);
+
        ret = device_list_add(path, disk_super, devid, fs_devices_ret);
 
 error_brelse:
@@ -243,6 +262,10 @@ static int find_free_dev_extent(struct btrfs_trans_handle *trans,
         * so we make sure to start at an offset of at least 1MB
         */
        search_start = max((u64)1024 * 1024, search_start);
+
+       if (root->fs_info->alloc_start + num_bytes <= device->total_bytes)
+               search_start = max(root->fs_info->alloc_start, search_start);
+
        key.objectid = device->devid;
        key.offset = search_start;
        key.type = BTRFS_DEV_EXTENT_KEY;
@@ -465,7 +488,7 @@ int btrfs_add_device(struct btrfs_trans_handle *trans,
        struct extent_buffer *leaf;
        struct btrfs_key key;
        unsigned long ptr;
-       u64 free_devid;
+       u64 free_devid = 0;
 
        root = root->fs_info->chunk_root;
 
@@ -491,6 +514,7 @@ int btrfs_add_device(struct btrfs_trans_handle *trans,
 
        device->devid = free_devid;
        btrfs_set_device_id(leaf, dev_item, device->devid);
+       btrfs_set_device_generation(leaf, dev_item, 0);
        btrfs_set_device_type(leaf, dev_item, device->type);
        btrfs_set_device_io_align(leaf, dev_item, device->io_align);
        btrfs_set_device_io_width(leaf, dev_item, device->io_width);
@@ -500,9 +524,12 @@ int btrfs_add_device(struct btrfs_trans_handle *trans,
        btrfs_set_device_group(leaf, dev_item, 0);
        btrfs_set_device_seek_speed(leaf, dev_item, 0);
        btrfs_set_device_bandwidth(leaf, dev_item, 0);
+       btrfs_set_device_start_offset(leaf, dev_item, 0);
 
        ptr = (unsigned long)btrfs_device_uuid(dev_item);
        write_extent_buffer(leaf, device->uuid, ptr, BTRFS_UUID_SIZE);
+       ptr = (unsigned long)btrfs_device_fsid(dev_item);
+       write_extent_buffer(leaf, root->fs_info->fsid, ptr, BTRFS_UUID_SIZE);
        btrfs_mark_buffer_dirty(leaf);
        ret = 0;
 
@@ -581,6 +608,26 @@ int btrfs_add_system_chunk(struct btrfs_trans_handle *trans,
        return 0;
 }
 
+static u64 div_factor(u64 num, int factor)
+{
+       if (factor == 10)
+               return num;
+       num *= factor;
+       return num / 10;
+}
+
+static u64 chunk_bytes_by_type(u64 type, u64 calc_size, int num_stripes,
+                              int sub_stripes)
+{
+       if (type & (BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_DUP))
+               return calc_size;
+       else if (type & BTRFS_BLOCK_GROUP_RAID10)
+               return calc_size * (num_stripes / sub_stripes);
+       else
+               return calc_size * num_stripes;
+}
+
+
 int btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
                      struct btrfs_root *extent_root, u64 *start,
                      u64 *num_bytes, u64 type)
@@ -595,12 +642,15 @@ int btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
        struct list_head *dev_list = &extent_root->fs_info->fs_devices->devices;
        struct list_head *cur;
        struct map_lookup *map;
-       u64 physical;
+       int min_stripe_size = 1 * 1024 * 1024;
        u64 calc_size = 8 * 1024 * 1024;
-       u64 min_free = calc_size;
+       u64 min_free;
+       u64 max_chunk_size = 4 * calc_size;
        u64 avail;
        u64 max_avail = 0;
+       u64 percent_max;
        int num_stripes = 1;
+       int min_stripes = 1;
        int sub_stripes = 0;
        int looped = 0;
        int ret;
@@ -615,52 +665,96 @@ int btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
        if (type & (BTRFS_BLOCK_GROUP_RAID0 | BTRFS_BLOCK_GROUP_RAID1 |
                    BTRFS_BLOCK_GROUP_RAID10 |
                    BTRFS_BLOCK_GROUP_DUP)) {
-               if (type & BTRFS_BLOCK_GROUP_SYSTEM)
-                       calc_size = 128 * 1024 * 1024;
-               else
+               if (type & BTRFS_BLOCK_GROUP_SYSTEM) {
+                       calc_size = 8 * 1024 * 1024;
+                       max_chunk_size = calc_size * 2;
+                       min_stripe_size = 1 * 1024 * 1024;
+               } else if (type & BTRFS_BLOCK_GROUP_DATA) {
                        calc_size = 1024 * 1024 * 1024;
+                       max_chunk_size = 10 * calc_size;
+                       min_stripe_size = 64 * 1024 * 1024;
+               } else if (type & BTRFS_BLOCK_GROUP_METADATA) {
+                       calc_size = 1024 * 1024 * 1024;
+                       max_chunk_size = 4 * calc_size;
+                       min_stripe_size = 32 * 1024 * 1024;
+               }
        }
        if (type & BTRFS_BLOCK_GROUP_RAID1) {
                num_stripes = min_t(u64, 2,
                                  btrfs_super_num_devices(&info->super_copy));
+               if (num_stripes < 2)
+                       return -ENOSPC;
+               min_stripes = 2;
        }
-       if (type & BTRFS_BLOCK_GROUP_DUP)
+       if (type & BTRFS_BLOCK_GROUP_DUP) {
                num_stripes = 2;
-       if (type & (BTRFS_BLOCK_GROUP_RAID0))
+               min_stripes = 2;
+       }
+       if (type & (BTRFS_BLOCK_GROUP_RAID0)) {
                num_stripes = btrfs_super_num_devices(&info->super_copy);
+               min_stripes = 2;
+       }
        if (type & (BTRFS_BLOCK_GROUP_RAID10)) {
                num_stripes = btrfs_super_num_devices(&info->super_copy);
                if (num_stripes < 4)
                        return -ENOSPC;
                num_stripes &= ~(u32)1;
                sub_stripes = 2;
+               min_stripes = 4;
        }
+
+       /* we don't want a chunk larger than 10% of the FS */
+       percent_max = div_factor(btrfs_super_total_bytes(&info->super_copy), 1);
+       max_chunk_size = min(percent_max, max_chunk_size);
+
 again:
+       if (chunk_bytes_by_type(type, calc_size, num_stripes, sub_stripes) >
+           max_chunk_size) {
+               calc_size = max_chunk_size;
+               calc_size /= num_stripes;
+               calc_size /= stripe_len;
+               calc_size *= stripe_len;
+       }
+       /* we don't want tiny stripes */
+       calc_size = max_t(u64, calc_size, min_stripe_size);
+
+       calc_size /= stripe_len;
+       calc_size *= stripe_len;
        INIT_LIST_HEAD(&private_devs);
        cur = dev_list->next;
        index = 0;
 
        if (type & BTRFS_BLOCK_GROUP_DUP)
                min_free = calc_size * 2;
+       else
+               min_free = calc_size;
 
        /* build a private list of devices we will allocate from */
        while(index < num_stripes) {
                device = list_entry(cur, struct btrfs_device, dev_list);
                avail = device->total_bytes - device->bytes_used;
                cur = cur->next;
-               if (avail > max_avail)
-                       max_avail = avail;
                if (avail >= min_free) {
                        list_move_tail(&device->dev_list, &private_devs);
                        index++;
                        if (type & BTRFS_BLOCK_GROUP_DUP)
                                index++;
-               }
+               } else if (avail > max_avail)
+                       max_avail = avail;
                if (cur == dev_list)
                        break;
        }
        if (index < num_stripes) {
                list_splice(&private_devs, dev_list);
+               if (index >= min_stripes) {
+                       num_stripes = index;
+                       if (type & (BTRFS_BLOCK_GROUP_RAID10)) {
+                               num_stripes /= sub_stripes;
+                               num_stripes *= sub_stripes;
+                       }
+                       looped = 1;
+                       goto again;
+               }
                if (!looped && max_avail > 0) {
                        looped = 1;
                        calc_size = max_avail;
@@ -668,7 +762,6 @@ again:
                }
                return -ENOSPC;
        }
-
        key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
        key.type = BTRFS_CHUNK_ITEM_KEY;
        ret = find_next_chunk(chunk_root, BTRFS_FIRST_CHUNK_TREE_OBJECTID,
@@ -687,16 +780,9 @@ again:
        }
 
        stripes = &chunk->stripe;
-
-       if (type & (BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_DUP))
-               *num_bytes = calc_size;
-       else if (type & BTRFS_BLOCK_GROUP_RAID10)
-               *num_bytes = calc_size * num_stripes / sub_stripes;
-       else
-               *num_bytes = calc_size * num_stripes;
-
+       *num_bytes = chunk_bytes_by_type(type, calc_size,
+                                        num_stripes, sub_stripes);
        index = 0;
-printk("new chunk type %Lu start %Lu size %Lu\n", type, key.offset, *num_bytes);
        while(index < num_stripes) {
                struct btrfs_stripe *stripe;
                BUG_ON(list_empty(&private_devs));
@@ -713,10 +799,7 @@ printk("new chunk type %Lu start %Lu size %Lu\n", type, key.offset, *num_bytes);
                             BTRFS_FIRST_CHUNK_TREE_OBJECTID, key.offset,
                             calc_size, &dev_offset);
                BUG_ON(ret);
-printk("\talloc chunk size %llu from dev %llu phys %llu\n",
-       (unsigned long long)calc_size,
-       (unsigned long long)device->devid,
-       (unsigned long long)dev_offset);
+
                device->bytes_used += calc_size;
                ret = btrfs_update_device(trans, device);
                BUG_ON(ret);
@@ -727,7 +810,6 @@ printk("\talloc chunk size %llu from dev %llu phys %llu\n",
                btrfs_set_stack_stripe_devid(stripe, device->devid);
                btrfs_set_stack_stripe_offset(stripe, dev_offset);
                memcpy(stripe->dev_uuid, device->uuid, BTRFS_UUID_SIZE);
-               physical = dev_offset;
                index++;
        }
        BUG_ON(!list_empty(&private_devs));
@@ -773,6 +855,108 @@ printk("\talloc chunk size %llu from dev %llu phys %llu\n",
        return ret;
 }
 
+int btrfs_alloc_data_chunk(struct btrfs_trans_handle *trans,
+                          struct btrfs_root *extent_root, u64 *start,
+                          u64 num_bytes, u64 type)
+{
+       u64 dev_offset;
+       struct btrfs_fs_info *info = extent_root->fs_info;
+       struct btrfs_root *chunk_root = extent_root->fs_info->chunk_root;
+       struct btrfs_stripe *stripes;
+       struct btrfs_device *device = NULL;
+       struct btrfs_chunk *chunk;
+       struct list_head *dev_list = &extent_root->fs_info->fs_devices->devices;
+       struct list_head *cur;
+       struct map_lookup *map;
+       u64 calc_size = 8 * 1024 * 1024;
+       int num_stripes = 1;
+       int sub_stripes = 0;
+       int ret;
+       int index;
+       int stripe_len = 64 * 1024;
+       struct btrfs_key key;
+
+       key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
+       key.type = BTRFS_CHUNK_ITEM_KEY;
+       ret = find_next_chunk(chunk_root, BTRFS_FIRST_CHUNK_TREE_OBJECTID,
+                             &key.offset);
+       if (ret)
+               return ret;
+
+       chunk = kmalloc(btrfs_chunk_item_size(num_stripes), GFP_NOFS);
+       if (!chunk)
+               return -ENOMEM;
+
+       map = kmalloc(map_lookup_size(num_stripes), GFP_NOFS);
+       if (!map) {
+               kfree(chunk);
+               return -ENOMEM;
+       }
+
+       stripes = &chunk->stripe;
+       calc_size = num_bytes;
+
+       index = 0;
+       cur = dev_list->next;
+       device = list_entry(cur, struct btrfs_device, dev_list);
+
+       while (index < num_stripes) {
+               struct btrfs_stripe *stripe;
+
+               ret = btrfs_alloc_dev_extent(trans, device,
+                            info->chunk_root->root_key.objectid,
+                            BTRFS_FIRST_CHUNK_TREE_OBJECTID, key.offset,
+                            calc_size, &dev_offset);
+               BUG_ON(ret);
+
+               device->bytes_used += calc_size;
+               ret = btrfs_update_device(trans, device);
+               BUG_ON(ret);
+
+               map->stripes[index].dev = device;
+               map->stripes[index].physical = dev_offset;
+               stripe = stripes + index;
+               btrfs_set_stack_stripe_devid(stripe, device->devid);
+               btrfs_set_stack_stripe_offset(stripe, dev_offset);
+               memcpy(stripe->dev_uuid, device->uuid, BTRFS_UUID_SIZE);
+               index++;
+       }
+
+       /* key was set above */
+       btrfs_set_stack_chunk_length(chunk, num_bytes);
+       btrfs_set_stack_chunk_owner(chunk, extent_root->root_key.objectid);
+       btrfs_set_stack_chunk_stripe_len(chunk, stripe_len);
+       btrfs_set_stack_chunk_type(chunk, type);
+       btrfs_set_stack_chunk_num_stripes(chunk, num_stripes);
+       btrfs_set_stack_chunk_io_align(chunk, stripe_len);
+       btrfs_set_stack_chunk_io_width(chunk, stripe_len);
+       btrfs_set_stack_chunk_sector_size(chunk, extent_root->sectorsize);
+       btrfs_set_stack_chunk_sub_stripes(chunk, sub_stripes);
+       map->sector_size = extent_root->sectorsize;
+       map->stripe_len = stripe_len;
+       map->io_align = stripe_len;
+       map->io_width = stripe_len;
+       map->type = type;
+       map->num_stripes = num_stripes;
+       map->sub_stripes = sub_stripes;
+
+       ret = btrfs_insert_item(trans, chunk_root, &key, chunk,
+                               btrfs_chunk_item_size(num_stripes));
+       BUG_ON(ret);
+       *start = key.offset;
+
+       map->ce.start = key.offset;
+       map->ce.size = num_bytes;
+
+       ret = insert_existing_cache_extent(
+                          &extent_root->fs_info->mapping_tree.cache_tree,
+                          &map->ce);
+       BUG_ON(ret);
+
+       kfree(chunk);
+       return ret;
+}
+
 void btrfs_mapping_init(struct btrfs_mapping_tree *tree)
 {
        cache_tree_init(&tree->cache_tree);
@@ -783,14 +967,12 @@ int btrfs_num_copies(struct btrfs_mapping_tree *map_tree, u64 logical, u64 len)
        struct cache_extent *ce;
        struct map_lookup *map;
        int ret;
-       u64 offset;
 
        ce = find_first_cache_extent(&map_tree->cache_tree, logical);
        BUG_ON(!ce);
        BUG_ON(ce->start > logical || ce->start + ce->size < logical);
        map = container_of(ce, struct map_lookup, ce);
 
-       offset = logical - ce->start;
        if (map->type & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1))
                ret = map->num_stripes;
        else if (map->type & BTRFS_BLOCK_GROUP_RAID10)
@@ -800,10 +982,98 @@ int btrfs_num_copies(struct btrfs_mapping_tree *map_tree, u64 logical, u64 len)
        return ret;
 }
 
+int btrfs_next_metadata(struct btrfs_mapping_tree *map_tree, u64 *logical,
+                       u64 *size)
+{
+       struct cache_extent *ce;
+       struct map_lookup *map;
+
+       ce = find_first_cache_extent(&map_tree->cache_tree, *logical);
+
+       while (ce) {
+               ce = next_cache_extent(ce);
+               if (!ce)
+                       return -ENOENT;
+
+               map = container_of(ce, struct map_lookup, ce);
+               if (map->type & BTRFS_BLOCK_GROUP_METADATA) {
+                       *logical = ce->start;
+                       *size = ce->size;
+                       return 0;
+               }
+       }
+
+       return -ENOENT;
+}
+
+int btrfs_rmap_block(struct btrfs_mapping_tree *map_tree,
+                    u64 chunk_start, u64 physical, u64 devid,
+                    u64 **logical, int *naddrs, int *stripe_len)
+{
+       struct cache_extent *ce;
+       struct map_lookup *map;
+       u64 *buf;
+       u64 bytenr;
+       u64 length;
+       u64 stripe_nr;
+       int i, j, nr = 0;
+
+       ce = find_first_cache_extent(&map_tree->cache_tree, chunk_start);
+       BUG_ON(!ce);
+       map = container_of(ce, struct map_lookup, ce);
+
+       length = ce->size;
+       if (map->type & BTRFS_BLOCK_GROUP_RAID10)
+               length = ce->size / (map->num_stripes / map->sub_stripes);
+       else if (map->type & BTRFS_BLOCK_GROUP_RAID0)
+               length = ce->size / map->num_stripes;
+
+       buf = kzalloc(sizeof(u64) * map->num_stripes, GFP_NOFS);
+
+       for (i = 0; i < map->num_stripes; i++) {
+               if (devid && map->stripes[i].dev->devid != devid)
+                       continue;
+               if (map->stripes[i].physical > physical ||
+                   map->stripes[i].physical + length <= physical)
+                       continue;
+
+               stripe_nr = (physical - map->stripes[i].physical) /
+                           map->stripe_len;
+
+               if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
+                       stripe_nr = (stripe_nr * map->num_stripes + i) /
+                                   map->sub_stripes;
+               } else if (map->type & BTRFS_BLOCK_GROUP_RAID0) {
+                       stripe_nr = stripe_nr * map->num_stripes + i;
+               }
+               bytenr = ce->start + stripe_nr * map->stripe_len;
+               for (j = 0; j < nr; j++) {
+                       if (buf[j] == bytenr)
+                               break;
+               }
+               if (j == nr)
+                       buf[nr++] = bytenr;
+       }
+
+       *logical = buf;
+       *naddrs = nr;
+       *stripe_len = map->stripe_len;
+
+       return 0;
+}
+
 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)
 {
+       return __btrfs_map_block(map_tree, rw, logical, length, NULL,
+                                multi_ret, mirror_num);
+}
+
+int __btrfs_map_block(struct btrfs_mapping_tree *map_tree, int rw,
+                   u64 logical, u64 *length, u64 *type,
+                   struct btrfs_multi_bio **multi_ret, int mirror_num)
+{
        struct cache_extent *ce;
        struct map_lookup *map;
        u64 offset;
@@ -819,16 +1089,24 @@ int btrfs_map_block(struct btrfs_mapping_tree *map_tree, int rw,
                stripes_allocated = 1;
        }
 again:
+       ce = find_first_cache_extent(&map_tree->cache_tree, logical);
+       if (!ce) {
+               if (multi)
+                       kfree(multi);
+               return -ENOENT;
+       }
+       if (ce->start > logical || ce->start + ce->size < logical) {
+               if (multi)
+                       kfree(multi);
+               return -ENOENT;
+       }
+
        if (multi_ret) {
                multi = kzalloc(btrfs_multi_bio_size(stripes_allocated),
                                GFP_NOFS);
                if (!multi)
                        return -ENOMEM;
        }
-
-       ce = find_first_cache_extent(&map_tree->cache_tree, logical);
-       BUG_ON(!ce);
-       BUG_ON(ce->start > logical || ce->start + ce->size < logical);
        map = container_of(ce, struct map_lookup, ce);
        offset = logical - ce->start;
 
@@ -892,8 +1170,6 @@ again:
                        multi->num_stripes = map->sub_stripes;
                else if (mirror_num)
                        stripe_index += mirror_num - 1;
-               else
-                       stripe_index = stripe_nr % map->sub_stripes;
 
                stripe_nr = stripe_nr / factor;
        } else if (map->type & BTRFS_BLOCK_GROUP_DUP) {
@@ -912,7 +1188,6 @@ again:
        }
        BUG_ON(stripe_index >= map->num_stripes);
 
-       BUG_ON(stripe_index != 0 && multi->num_stripes > 1);
        for (i = 0; i < multi->num_stripes; i++) {
                multi->stripes[i].physical =
                        map->stripes[stripe_index].physical + stripe_offset +
@@ -921,16 +1196,30 @@ again:
                stripe_index++;
        }
        *multi_ret = multi;
+       if (type)
+               *type = map->type;
 out:
        return 0;
 }
 
 struct btrfs_device *btrfs_find_device(struct btrfs_root *root, u64 devid,
-                                      u8 *uuid)
+                                      u8 *uuid, u8 *fsid)
 {
-       struct list_head *head = &root->fs_info->fs_devices->devices;
-
-       return __find_device(head, devid, uuid);
+       struct btrfs_device *device;
+       struct btrfs_fs_devices *cur_devices;
+
+       cur_devices = root->fs_info->fs_devices;
+       while (cur_devices) {
+               if (!fsid ||
+                   !memcmp(cur_devices->fsid, fsid, BTRFS_UUID_SIZE)) {
+                       device = __find_device(&cur_devices->devices,
+                                              devid, uuid);
+                       if (device)
+                               return device;
+               }
+               cur_devices = cur_devices->seed;
+       }
+       return NULL;
 }
 
 int btrfs_bootstrap_super_map(struct btrfs_mapping_tree *map_tree,
@@ -986,6 +1275,38 @@ int btrfs_bootstrap_super_map(struct btrfs_mapping_tree *map_tree,
        return 0;
 }
 
+int btrfs_chunk_readonly(struct btrfs_root *root, u64 chunk_offset)
+{
+       struct cache_extent *ce;
+       struct map_lookup *map;
+       struct btrfs_mapping_tree *map_tree = &root->fs_info->mapping_tree;
+       int readonly = 0;
+       int i;
+
+       ce = find_first_cache_extent(&map_tree->cache_tree, chunk_offset);
+       BUG_ON(!ce);
+
+       map = container_of(ce, struct map_lookup, ce);
+       for (i = 0; i < map->num_stripes; i++) {
+               if (!map->stripes[i].dev->writeable) {
+                       readonly = 1;
+                       break;
+               }
+       }
+
+       return readonly;
+}
+
+static struct btrfs_device *fill_missing_device(u64 devid)
+{
+       struct btrfs_device *device;
+
+       device = kzalloc(sizeof(*device), GFP_NOFS);
+       device->devid = devid;
+       device->fd = -1;
+       return device;
+}
+
 static int read_one_chunk(struct btrfs_root *root, struct btrfs_key *key,
                          struct extent_buffer *leaf,
                          struct btrfs_chunk *chunk)
@@ -996,7 +1317,6 @@ static int read_one_chunk(struct btrfs_root *root, struct btrfs_key *key,
        u64 logical;
        u64 length;
        u64 devid;
-       u64 super_offset_diff = 0;
        u8 uuid[BTRFS_UUID_SIZE];
        int num_stripes;
        int ret;
@@ -1005,12 +1325,6 @@ static int read_one_chunk(struct btrfs_root *root, struct btrfs_key *key,
        logical = key->offset;
        length = btrfs_chunk_length(leaf, chunk);
 
-       if (logical < BTRFS_SUPER_INFO_OFFSET + BTRFS_SUPER_INFO_SIZE) {
-               super_offset_diff = BTRFS_SUPER_INFO_OFFSET +
-                       BTRFS_SUPER_INFO_SIZE - logical;
-               logical = BTRFS_SUPER_INFO_OFFSET + BTRFS_SUPER_INFO_SIZE;
-       }
-
        ce = find_first_cache_extent(&map_tree->cache_tree, logical);
 
        /* already mapped? */
@@ -1024,7 +1338,7 @@ static int read_one_chunk(struct btrfs_root *root, struct btrfs_key *key,
                return -ENOMEM;
 
        map->ce.start = logical;
-       map->ce.size = length - super_offset_diff;
+       map->ce.size = length;
        map->num_stripes = num_stripes;
        map->io_width = btrfs_chunk_io_width(leaf, chunk);
        map->io_align = btrfs_chunk_io_align(leaf, chunk);
@@ -1035,16 +1349,17 @@ static int read_one_chunk(struct btrfs_root *root, struct btrfs_key *key,
 
        for (i = 0; i < num_stripes; i++) {
                map->stripes[i].physical =
-                       btrfs_stripe_offset_nr(leaf, chunk, i) +
-                               super_offset_diff;
+                       btrfs_stripe_offset_nr(leaf, chunk, i);
                devid = btrfs_stripe_devid_nr(leaf, chunk, i);
                read_extent_buffer(leaf, uuid, (unsigned long)
                                   btrfs_stripe_dev_uuid_nr(chunk, i),
                                   BTRFS_UUID_SIZE);
-               map->stripes[i].dev = btrfs_find_device(root, devid, uuid);
+               map->stripes[i].dev = btrfs_find_device(root, devid, uuid,
+                                                       NULL);
                if (!map->stripes[i].dev) {
-                       kfree(map);
-                       return -EIO;
+                       map->stripes[i].dev = fill_missing_device(devid);
+                       printf("warning, device %llu is missing\n",
+                              (unsigned long long)devid);
                }
 
        }
@@ -1074,6 +1389,36 @@ static int fill_device_from_item(struct extent_buffer *leaf,
        return 0;
 }
 
+static int open_seed_devices(struct btrfs_root *root, u8 *fsid)
+{
+       struct btrfs_fs_devices *fs_devices;
+       int ret;
+
+       fs_devices = root->fs_info->fs_devices->seed;
+       while (fs_devices) {
+               if (!memcmp(fs_devices->fsid, fsid, BTRFS_UUID_SIZE)) {
+                       ret = 0;
+                       goto out;
+               }
+               fs_devices = fs_devices->seed;
+       }
+
+       fs_devices = find_fsid(fsid);
+       if (!fs_devices) {
+               ret = -ENOENT;
+               goto out;
+       }
+
+       ret = btrfs_open_devices(fs_devices, O_RDONLY);
+       if (ret)
+               goto out;
+
+       fs_devices->seed = root->fs_info->fs_devices->seed;
+       root->fs_info->fs_devices->seed = fs_devices;
+out:
+       return ret;
+}
+
 static int read_one_dev(struct btrfs_root *root,
                        struct extent_buffer *leaf,
                        struct btrfs_dev_item *dev_item)
@@ -1081,13 +1426,24 @@ static int read_one_dev(struct btrfs_root *root,
        struct btrfs_device *device;
        u64 devid;
        int ret = 0;
+       u8 fs_uuid[BTRFS_UUID_SIZE];
        u8 dev_uuid[BTRFS_UUID_SIZE];
 
        devid = btrfs_device_id(leaf, dev_item);
        read_extent_buffer(leaf, dev_uuid,
                           (unsigned long)btrfs_device_uuid(dev_item),
                           BTRFS_UUID_SIZE);
-       device = btrfs_find_device(root, devid, dev_uuid);
+       read_extent_buffer(leaf, fs_uuid,
+                          (unsigned long)btrfs_device_fsid(dev_item),
+                          BTRFS_UUID_SIZE);
+
+       if (memcmp(fs_uuid, root->fs_info->fsid, BTRFS_UUID_SIZE)) {
+               ret = open_seed_devices(root, fs_uuid);
+               if (ret)
+                       return ret;
+       }
+
+       device = btrfs_find_device(root, devid, dev_uuid, fs_uuid);
        if (!device) {
                printk("warning devid %llu not found already\n",
                        (unsigned long long)devid);
@@ -1116,7 +1472,7 @@ int btrfs_read_super_device(struct btrfs_root *root, struct extent_buffer *buf)
 int btrfs_read_sys_array(struct btrfs_root *root)
 {
        struct btrfs_super_block *super_copy = &root->fs_info->super_copy;
-       struct extent_buffer *sb = root->fs_info->sb_buffer;
+       struct extent_buffer *sb;
        struct btrfs_disk_key *disk_key;
        struct btrfs_chunk *chunk;
        struct btrfs_key key;
@@ -1126,8 +1482,14 @@ int btrfs_read_sys_array(struct btrfs_root *root)
        u8 *ptr;
        unsigned long sb_ptr;
        u32 cur;
-       int ret;
+       int ret = 0;
 
+       sb = btrfs_find_create_tree_block(root, BTRFS_SUPER_INFO_OFFSET,
+                                         BTRFS_SUPER_INFO_SIZE);
+       if (!sb)
+               return -ENOMEM;
+       btrfs_set_buffer_uptodate(sb);
+       write_extent_buffer(sb, super_copy, 0, BTRFS_SUPER_INFO_SIZE);
        array_size = btrfs_super_sys_array_size(super_copy);
 
        /*
@@ -1151,7 +1513,8 @@ int btrfs_read_sys_array(struct btrfs_root *root)
                if (key.type == BTRFS_CHUNK_ITEM_KEY) {
                        chunk = (struct btrfs_chunk *)sb_ptr;
                        ret = read_one_chunk(root, &key, sb, chunk);
-                       BUG_ON(ret);
+                       if (ret)
+                               break;
                        num_stripes = btrfs_chunk_num_stripes(sb, chunk);
                        len = btrfs_chunk_item_size(num_stripes);
                } else {
@@ -1161,7 +1524,8 @@ int btrfs_read_sys_array(struct btrfs_root *root)
                sb_ptr += len;
                cur += len;
        }
-       return 0;
+       free_extent_buffer(sb);
+       return ret;
 }
 
 int btrfs_read_chunk_tree(struct btrfs_root *root)
@@ -1214,6 +1578,7 @@ again:
                        struct btrfs_chunk *chunk;
                        chunk = btrfs_item_ptr(leaf, slot, struct btrfs_chunk);
                        ret = read_one_chunk(root, &found_key, leaf, chunk);
+                       BUG_ON(ret);
                }
                path->slots[0]++;
        }
@@ -1229,3 +1594,7 @@ error:
        return ret;
 }
 
+struct list_head *btrfs_scanned_uuids(void)
+{
+       return &fs_uuids;
+}