Btrfs: Make the resizer work based on shrinking and growing devices

Signed-off-by: Chris Mason <chris.mason@oracle.com>

1 files changed, 312 insertions, 12 deletions

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index c63a982e31d0..a2c56de1548a 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -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;
                 }
         }
@@ -293,6 +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;
@@ -380,6 +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,
@@ -560,6 +591,7 @@ out:
         btrfs_free_path(path);
         return ret;
 }
+
 int btrfs_update_device(struct btrfs_trans_handle *trans,
                         struct btrfs_device *device)
 {
@@ -606,6 +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,
@@ -658,6 +938,7 @@ 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;
@@ -724,6 +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);
@@ -759,11 +1044,19 @@ again:
 
                 avail = device->total_bytes - device->bytes_used;
                 cur = cur->next;
+
                 if (avail >= min_free) {
-                        list_move_tail(&device->dev_alloc_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)
@@ -785,30 +1078,37 @@ 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) {
@@ -874,6 +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;
@@ -1376,11 +1681,6 @@ int btrfs_read_sys_array(struct btrfs_root *root)
 
         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;