]> pilppa.org Git - linux-2.6-omap-h63xx.git/blobdiff - fs/btrfs/volumes.c
Btrfs: Make the resizer work based on shrinking and growing devices
[linux-2.6-omap-h63xx.git] / fs / btrfs / volumes.c
index 460240706505764f82169b2becea0a37b82488ce..a2c56de1548a8fb7e2c946c7588e39aa6d52c47b 100644 (file)
@@ -77,7 +77,7 @@ static struct btrfs_device *__find_device(struct list_head *head, u64 devid,
        list_for_each(cur, head) {
                dev = list_entry(cur, struct btrfs_device, dev_list);
                if (dev->devid == devid &&
-                   !memcmp(dev->uuid, uuid, BTRFS_UUID_SIZE)) {
+                   (!uuid || !memcmp(dev->uuid, uuid, BTRFS_UUID_SIZE))) {
                        return dev;
                }
        }
@@ -111,6 +111,7 @@ static int device_list_add(const char *path,
                if (!fs_devices)
                        return -ENOMEM;
                INIT_LIST_HEAD(&fs_devices->devices);
+               INIT_LIST_HEAD(&fs_devices->alloc_list);
                list_add(&fs_devices->list, &fs_uuids);
                memcpy(fs_devices->fsid, disk_super->fsid, BTRFS_FSID_SIZE);
                fs_devices->latest_devid = devid;
@@ -139,6 +140,7 @@ static int device_list_add(const char *path,
                        return -ENOMEM;
                }
                list_add(&device->dev_list, &fs_devices->devices);
+               list_add(&device->dev_alloc_list, &fs_devices->alloc_list);
                fs_devices->num_devices++;
        }
 
@@ -291,6 +293,10 @@ 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;
@@ -378,6 +384,33 @@ error:
        return ret;
 }
 
+int btrfs_free_dev_extent(struct btrfs_trans_handle *trans,
+                         struct btrfs_device *device,
+                         u64 start)
+{
+       int ret;
+       struct btrfs_path *path;
+       struct btrfs_root *root = device->dev_root;
+       struct btrfs_key key;
+
+       path = btrfs_alloc_path();
+       if (!path)
+               return -ENOMEM;
+
+       key.objectid = device->devid;
+       key.offset = start;
+       key.type = BTRFS_DEV_EXTENT_KEY;
+
+       ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
+       BUG_ON(ret);
+
+       ret = btrfs_del_item(trans, root, path);
+       BUG_ON(ret);
+
+       btrfs_free_path(path);
+       return ret;
+}
+
 int btrfs_alloc_dev_extent(struct btrfs_trans_handle *trans,
                           struct btrfs_device *device,
                           u64 chunk_tree, u64 chunk_objectid,
@@ -558,6 +591,7 @@ out:
        btrfs_free_path(path);
        return ret;
 }
+
 int btrfs_update_device(struct btrfs_trans_handle *trans,
                        struct btrfs_device *device)
 {
@@ -604,6 +638,254 @@ out:
        return ret;
 }
 
+int btrfs_grow_device(struct btrfs_trans_handle *trans,
+                     struct btrfs_device *device, u64 new_size)
+{
+       struct btrfs_super_block *super_copy =
+               &device->dev_root->fs_info->super_copy;
+       u64 old_total = btrfs_super_total_bytes(super_copy);
+       u64 diff = new_size - device->total_bytes;
+
+       btrfs_set_super_total_bytes(super_copy, old_total + diff);
+       return btrfs_update_device(trans, device);
+}
+
+static int btrfs_free_chunk(struct btrfs_trans_handle *trans,
+                           struct btrfs_root *root,
+                           u64 chunk_tree, u64 chunk_objectid,
+                           u64 chunk_offset)
+{
+       int ret;
+       struct btrfs_path *path;
+       struct btrfs_key key;
+
+       root = root->fs_info->chunk_root;
+       path = btrfs_alloc_path();
+       if (!path)
+               return -ENOMEM;
+
+       key.objectid = chunk_objectid;
+       key.offset = chunk_offset;
+       key.type = BTRFS_CHUNK_ITEM_KEY;
+
+       ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
+       BUG_ON(ret);
+
+       ret = btrfs_del_item(trans, root, path);
+       BUG_ON(ret);
+
+       btrfs_free_path(path);
+       return 0;
+}
+
+int btrfs_del_sys_chunk(struct btrfs_root *root, u64 chunk_objectid, u64
+                       chunk_offset)
+{
+       struct btrfs_super_block *super_copy = &root->fs_info->super_copy;
+       struct btrfs_disk_key *disk_key;
+       struct btrfs_chunk *chunk;
+       u8 *ptr;
+       int ret = 0;
+       u32 num_stripes;
+       u32 array_size;
+       u32 len = 0;
+       u32 cur;
+       struct btrfs_key key;
+
+       array_size = btrfs_super_sys_array_size(super_copy);
+
+       ptr = super_copy->sys_chunk_array;
+       cur = 0;
+
+       while (cur < array_size) {
+               disk_key = (struct btrfs_disk_key *)ptr;
+               btrfs_disk_key_to_cpu(&key, disk_key);
+
+               len = sizeof(*disk_key);
+
+               if (key.type == BTRFS_CHUNK_ITEM_KEY) {
+                       chunk = (struct btrfs_chunk *)(ptr + len);
+                       num_stripes = btrfs_stack_chunk_num_stripes(chunk);
+                       len += btrfs_chunk_item_size(num_stripes);
+               } else {
+                       ret = -EIO;
+                       break;
+               }
+               if (key.objectid == chunk_objectid &&
+                   key.offset == chunk_offset) {
+                       memmove(ptr, ptr + len, array_size - (cur + len));
+                       array_size -= len;
+                       btrfs_set_super_sys_array_size(super_copy, array_size);
+               } else {
+                       ptr += len;
+                       cur += len;
+               }
+       }
+       return ret;
+}
+
+
+int btrfs_relocate_chunk(struct btrfs_root *root,
+                        u64 chunk_tree, u64 chunk_objectid,
+                        u64 chunk_offset)
+{
+       struct extent_map_tree *em_tree;
+       struct btrfs_root *extent_root;
+       struct btrfs_trans_handle *trans;
+       struct extent_map *em;
+       struct map_lookup *map;
+       int ret;
+       int i;
+
+       root = root->fs_info->chunk_root;
+       extent_root = root->fs_info->extent_root;
+       em_tree = &root->fs_info->mapping_tree.map_tree;
+
+       /* step one, relocate all the extents inside this chunk */
+       ret = btrfs_shrink_extent_tree(extent_root, chunk_offset);
+       BUG_ON(ret);
+
+       trans = btrfs_start_transaction(root, 1);
+       BUG_ON(!trans);
+
+       /*
+        * step two, delete the device extents and the
+        * chunk tree entries
+        */
+       spin_lock(&em_tree->lock);
+       em = lookup_extent_mapping(em_tree, chunk_offset, 1);
+       spin_unlock(&em_tree->lock);
+
+       BUG_ON(em->start > chunk_offset || em->start + em->len < chunk_offset);
+       map = (struct map_lookup *)em->bdev;
+
+       for (i = 0; i < map->num_stripes; i++) {
+               ret = btrfs_free_dev_extent(trans, map->stripes[i].dev,
+                                           map->stripes[i].physical);
+               BUG_ON(ret);
+       }
+       ret = btrfs_free_chunk(trans, root, chunk_tree, chunk_objectid,
+                              chunk_offset);
+
+       BUG_ON(ret);
+
+       if (map->type & BTRFS_BLOCK_GROUP_SYSTEM) {
+               ret = btrfs_del_sys_chunk(root, chunk_objectid, chunk_offset);
+               BUG_ON(ret);
+               goto out;
+       }
+
+
+
+       spin_lock(&em_tree->lock);
+       remove_extent_mapping(em_tree, em);
+       kfree(map);
+       em->bdev = NULL;
+
+       /* once for the tree */
+       free_extent_map(em);
+       spin_unlock(&em_tree->lock);
+
+out:
+       /* once for us */
+       free_extent_map(em);
+
+       btrfs_end_transaction(trans, root);
+       return 0;
+}
+
+/*
+ * shrinking a device means finding all of the device extents past
+ * the new size, and then following the back refs to the chunks.
+ * The chunk relocation code actually frees the device extent
+ */
+int btrfs_shrink_device(struct btrfs_device *device, u64 new_size)
+{
+       struct btrfs_trans_handle *trans;
+       struct btrfs_root *root = device->dev_root;
+       struct btrfs_dev_extent *dev_extent = NULL;
+       struct btrfs_path *path;
+       u64 length;
+       u64 chunk_tree;
+       u64 chunk_objectid;
+       u64 chunk_offset;
+       int ret;
+       int slot;
+       struct extent_buffer *l;
+       struct btrfs_key key;
+       struct btrfs_super_block *super_copy = &root->fs_info->super_copy;
+       u64 old_total = btrfs_super_total_bytes(super_copy);
+       u64 diff = device->total_bytes - new_size;
+
+
+       path = btrfs_alloc_path();
+       if (!path)
+               return -ENOMEM;
+
+       trans = btrfs_start_transaction(root, 1);
+       if (!trans) {
+               ret = -ENOMEM;
+               goto done;
+       }
+
+       path->reada = 2;
+
+       device->total_bytes = new_size;
+       ret = btrfs_update_device(trans, device);
+       if (ret) {
+               btrfs_end_transaction(trans, root);
+               goto done;
+       }
+       WARN_ON(diff > old_total);
+       btrfs_set_super_total_bytes(super_copy, old_total - diff);
+       btrfs_end_transaction(trans, root);
+
+       key.objectid = device->devid;
+       key.offset = (u64)-1;
+       key.type = BTRFS_DEV_EXTENT_KEY;
+
+       while (1) {
+               ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
+               if (ret < 0)
+                       goto done;
+
+               ret = btrfs_previous_item(root, path, 0, key.type);
+               if (ret < 0)
+                       goto done;
+               if (ret) {
+                       ret = 0;
+                       goto done;
+               }
+
+               l = path->nodes[0];
+               slot = path->slots[0];
+               btrfs_item_key_to_cpu(l, &key, path->slots[0]);
+
+               if (key.objectid != device->devid)
+                       goto done;
+
+               dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
+               length = btrfs_dev_extent_length(l, dev_extent);
+
+               if (key.offset + length <= new_size)
+                       goto done;
+
+               chunk_tree = btrfs_dev_extent_chunk_tree(l, dev_extent);
+               chunk_objectid = btrfs_dev_extent_chunk_objectid(l, dev_extent);
+               chunk_offset = btrfs_dev_extent_chunk_offset(l, dev_extent);
+               btrfs_release_path(root, path);
+
+               ret = btrfs_relocate_chunk(root, chunk_tree, chunk_objectid,
+                                          chunk_offset);
+               if (ret)
+                       goto done;
+       }
+
+done:
+       btrfs_free_path(path);
+       return ret;
+}
+
 int btrfs_add_system_chunk(struct btrfs_trans_handle *trans,
                           struct btrfs_root *root,
                           struct btrfs_key *key,
@@ -656,11 +938,12 @@ int btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
        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_path *path;
        struct btrfs_stripe *stripes;
        struct btrfs_device *device = NULL;
        struct btrfs_chunk *chunk;
        struct list_head private_devs;
-       struct list_head *dev_list = &extent_root->fs_info->fs_devices->devices;
+       struct list_head *dev_list;
        struct list_head *cur;
        struct extent_map_tree *em_tree;
        struct map_lookup *map;
@@ -682,6 +965,7 @@ int btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
        int stripe_len = 64 * 1024;
        struct btrfs_key key;
 
+       dev_list = &extent_root->fs_info->fs_devices->alloc_list;
        if (list_empty(dev_list))
                return -ENOSPC;
 
@@ -721,6 +1005,10 @@ int btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
                min_stripe_size = 1 * 1024 * 1024;
        }
 
+       path = btrfs_alloc_path();
+       if (!path)
+               return -ENOMEM;
+
        /* 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);
@@ -752,15 +1040,23 @@ again:
 
        /* build a private list of devices we will allocate from */
        while(index < num_stripes) {
-               device = list_entry(cur, struct btrfs_device, dev_list);
+               device = list_entry(cur, struct btrfs_device, dev_alloc_list);
 
                avail = device->total_bytes - device->bytes_used;
                cur = cur->next;
+
                if (avail >= min_free) {
-                       list_move_tail(&device->dev_list, &private_devs);
-                       index++;
-                       if (type & BTRFS_BLOCK_GROUP_DUP)
+                       u64 ignored_start = 0;
+                       ret = find_free_dev_extent(trans, device, path,
+                                                  min_free,
+                                                  &ignored_start);
+                       if (ret == 0) {
+                               list_move_tail(&device->dev_alloc_list,
+                                              &private_devs);
                                index++;
+                               if (type & BTRFS_BLOCK_GROUP_DUP)
+                                       index++;
+                       }
                } else if (avail > max_avail)
                        max_avail = avail;
                if (cur == dev_list)
@@ -782,42 +1078,49 @@ again:
                        calc_size = max_avail;
                        goto again;
                }
+               btrfs_free_path(path);
                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,
                              &key.offset);
-       if (ret)
+       if (ret) {
+               btrfs_free_path(path);
                return ret;
+       }
 
        chunk = kmalloc(btrfs_chunk_item_size(num_stripes), GFP_NOFS);
-       if (!chunk)
+       if (!chunk) {
+               btrfs_free_path(path);
                return -ENOMEM;
+       }
 
        map = kmalloc(map_lookup_size(num_stripes), GFP_NOFS);
        if (!map) {
                kfree(chunk);
+               btrfs_free_path(path);
                return -ENOMEM;
        }
+       btrfs_free_path(path);
+       path = NULL;
 
        stripes = &chunk->stripe;
        *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));
                cur = private_devs.next;
-               device = list_entry(cur, struct btrfs_device, dev_list);
+               device = list_entry(cur, struct btrfs_device, dev_alloc_list);
 
                /* loop over this device again if we're doing a dup group */
                if (!(type & BTRFS_BLOCK_GROUP_DUP) ||
                    (index == num_stripes - 1))
-                       list_move_tail(&device->dev_list, dev_list);
+                       list_move_tail(&device->dev_alloc_list, dev_list);
 
                ret = btrfs_alloc_dev_extent(trans, device,
                             info->chunk_root->root_key.objectid,
@@ -871,6 +1174,11 @@ printk("alloc chunk start %Lu size %Lu from dev %Lu type %Lu\n", key.offset, cal
        em->len = *num_bytes;
        em->block_start = 0;
 
+       if (type & BTRFS_BLOCK_GROUP_SYSTEM) {
+               ret = btrfs_add_system_chunk(trans, chunk_root, &key,
+                                   chunk, btrfs_chunk_item_size(num_stripes));
+               BUG_ON(ret);
+       }
        kfree(chunk);
 
        em_tree = &extent_root->fs_info->mapping_tree.map_tree;
@@ -1029,19 +1337,8 @@ again:
                else if (mirror_num) {
                        stripe_index = mirror_num - 1;
                } 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);
-                       }
+                       u64 orig_stripe_nr = stripe_nr;
+                       stripe_index = do_div(orig_stripe_nr, num_stripes);
                }
        } else if (map->type & BTRFS_BLOCK_GROUP_DUP) {
                if (rw & (1 << BIO_RW))
@@ -1050,7 +1347,6 @@ again:
                        stripe_index = mirror_num - 1;
        } else if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
                int factor = map->num_stripes / map->sub_stripes;
-               int orig_stripe_nr = stripe_nr;
 
                stripe_index = do_div(stripe_nr, factor);
                stripe_index *= map->sub_stripes;
@@ -1059,8 +1355,11 @@ again:
                        num_stripes = map->sub_stripes;
                else if (mirror_num)
                        stripe_index += mirror_num - 1;
-               else
-                       stripe_index += orig_stripe_nr % map->sub_stripes;
+               else {
+                       u64 orig_stripe_nr = stripe_nr;
+                       stripe_index += do_div(orig_stripe_nr,
+                                              map->sub_stripes);
+               }
        } else {
                /*
                 * after this do_div call, stripe_nr is the number of stripes
@@ -1167,7 +1466,6 @@ int btrfs_map_bio(struct btrfs_root *root, int rw, struct bio *bio,
        int total_devs = 1;
 
        length = bio->bi_size;
-
        map_tree = &root->fs_info->mapping_tree;
        map_length = length;
 
@@ -1198,6 +1496,7 @@ int btrfs_map_bio(struct btrfs_root *root, int rw, struct bio *bio,
                }
                bio->bi_sector = multi->stripes[dev_nr].physical >> 9;
                dev = multi->stripes[dev_nr].dev;
+
                bio->bi_bdev = dev->bdev;
                spin_lock(&dev->io_lock);
                dev->total_ios++;
@@ -1338,6 +1637,8 @@ static int read_one_dev(struct btrfs_root *root,
                        return -ENOMEM;
                list_add(&device->dev_list,
                         &root->fs_info->fs_devices->devices);
+               list_add(&device->dev_alloc_list,
+                        &root->fs_info->fs_devices->alloc_list);
                device->barriers = 1;
                spin_lock_init(&device->io_lock);
        }
@@ -1369,22 +1670,17 @@ int btrfs_read_sys_array(struct btrfs_root *root)
        struct extent_buffer *sb = root->fs_info->sb_buffer;
        struct btrfs_disk_key *disk_key;
        struct btrfs_chunk *chunk;
-       struct btrfs_key key;
+       u8 *ptr;
+       unsigned long sb_ptr;
+       int ret = 0;
        u32 num_stripes;
        u32 array_size;
        u32 len = 0;
-       u8 *ptr;
-       unsigned long sb_ptr;
        u32 cur;
-       int ret;
+       struct btrfs_key key;
 
        array_size = btrfs_super_sys_array_size(super_copy);
 
-       /*
-        * we do this loop twice, once for the device items and
-        * once for all of the chunks.  This way there are device
-        * structs filled in for every chunk
-        */
        ptr = super_copy->sys_chunk_array;
        sb_ptr = offsetof(struct btrfs_super_block, sys_chunk_array);
        cur = 0;
@@ -1401,17 +1697,19 @@ 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 {
-                       BUG();
+                       ret = -EIO;
+                       break;
                }
                ptr += len;
                sb_ptr += len;
                cur += len;
        }
-       return 0;
+       return ret;
 }
 
 int btrfs_read_chunk_tree(struct btrfs_root *root)