Btrfs: Make the resizer work based on shrinking and growing devices
Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index c63a982..a2c56de1 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -77,7 +77,7 @@
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 @@
* 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 @@
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 @@
btrfs_free_path(path);
return ret;
}
+
int btrfs_update_device(struct btrfs_trans_handle *trans,
struct btrfs_device *device)
{
@@ -606,6 +638,254 @@
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 @@
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 @@
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 @@
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 @@
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 @@
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 @@
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;
