btrfs-progs: convert: Introduce new function to create converted image

Use new function, create_convert_image_v2() to create snapshot of old
filesystem.

Unlike old function which is called after copying all inodes, this
function need to be called before copying inodes.

Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: David Sterba <dsterba@suse.com>
master
Qu Wenruo 2016-01-29 13:03:25 +08:00 committed by David Sterba
parent a21cc1ca3f
commit e653d42658
1 changed files with 184 additions and 0 deletions

View File

@ -1439,6 +1439,7 @@ static int create_image_file_range(struct btrfs_trans_handle *trans,
fail:
return ret;
}
/*
* Create the fs image file.
*/
@ -1632,6 +1633,189 @@ fail:
return ret;
}
static int create_image_file_range_v2(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct cache_tree *used,
struct btrfs_inode_item *inode,
u64 ino, u64 bytenr, u64 *ret_len,
int datacsum)
{
struct cache_extent *cache;
struct btrfs_block_group_cache *bg_cache;
u64 len = *ret_len;
u64 disk_bytenr;
int ret;
BUG_ON(bytenr != round_down(bytenr, root->sectorsize));
BUG_ON(len != round_down(len, root->sectorsize));
len = min_t(u64, len, BTRFS_MAX_EXTENT_SIZE);
cache = search_cache_extent(used, bytenr);
if (cache) {
if (cache->start <= bytenr) {
/*
* |///////Used///////|
* |<--insert--->|
* bytenr
*/
len = min_t(u64, len, cache->start + cache->size -
bytenr);
disk_bytenr = bytenr;
} else {
/*
* |//Used//|
* |<-insert-->|
* bytenr
*/
len = min(len, cache->start - bytenr);
disk_bytenr = 0;
datacsum = 0;
}
} else {
/*
* |//Used//| |EOF
* |<-insert-->|
* bytenr
*/
disk_bytenr = 0;
datacsum = 0;
}
if (disk_bytenr) {
/* Check if the range is in a data block group */
bg_cache = btrfs_lookup_block_group(root->fs_info, bytenr);
if (!bg_cache)
return -ENOENT;
if (!(bg_cache->flags & BTRFS_BLOCK_GROUP_DATA))
return -EINVAL;
/* The extent should never cross block group boundary */
len = min_t(u64, len, bg_cache->key.objectid +
bg_cache->key.offset - bytenr);
}
BUG_ON(len != round_down(len, root->sectorsize));
ret = btrfs_record_file_extent(trans, root, ino, inode, bytenr,
disk_bytenr, len);
if (ret < 0)
return ret;
if (datacsum)
ret = csum_disk_extent(trans, root, bytenr, len);
*ret_len = len;
return ret;
}
static int wipe_reserved_ranges(struct cache_tree *tree, u64 min_stripe_size,
int ensure_size);
/*
* Create the fs image file of old filesystem.
*
* This is completely fs independent as we have cctx->used, only
* need to create file extents pointing to all the positions.
* TODO: Add handler for reserved ranges in next patch
*/
static int create_image_v2(struct btrfs_root *root,
struct btrfs_mkfs_config *cfg,
struct btrfs_convert_context *cctx,
u64 size, char *name, int datacsum)
{
struct btrfs_inode_item buf;
struct btrfs_trans_handle *trans;
struct btrfs_path *path = NULL;
struct btrfs_key key;
struct cache_extent *cache;
struct cache_tree used_tmp;
u64 cur;
u64 ino;
int ret;
trans = btrfs_start_transaction(root, 1);
if (!trans)
return -ENOMEM;
cache_tree_init(&used_tmp);
ret = btrfs_find_free_objectid(trans, root, BTRFS_FIRST_FREE_OBJECTID,
&ino);
if (ret < 0)
goto out;
ret = btrfs_new_inode(trans, root, ino, 0600 | S_IFREG);
if (ret < 0)
goto out;
ret = btrfs_add_link(trans, root, ino, BTRFS_FIRST_FREE_OBJECTID, name,
strlen(name), BTRFS_FT_REG_FILE, NULL, 1);
if (ret < 0)
goto out;
path = btrfs_alloc_path();
if (!path) {
ret = -ENOMEM;
goto out;
}
key.objectid = ino;
key.type = BTRFS_INODE_ITEM_KEY;
key.offset = 0;
ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
if (ret) {
ret = (ret > 0 ? -ENOENT : ret);
goto out;
}
read_extent_buffer(path->nodes[0], &buf,
btrfs_item_ptr_offset(path->nodes[0], path->slots[0]),
sizeof(buf));
btrfs_release_path(path);
/*
* Create a new used space cache, which doesn't contain the reserved
* range
*/
for (cache = first_cache_extent(&cctx->used); cache;
cache = next_cache_extent(cache)) {
ret = add_cache_extent(&used_tmp, cache->start, cache->size);
if (ret < 0)
goto out;
}
ret = wipe_reserved_ranges(&used_tmp, 0, 0);
if (ret < 0)
goto out;
/*
* Start from 1M, as 0~1M is reserved, and create_image_file_range_v2()
* can't handle bytenr 0(will consider it as a hole)
*/
cur = 1024 * 1024;
while (cur < size) {
u64 len = size - cur;
ret = create_image_file_range_v2(trans, root, &used_tmp,
&buf, ino, cur, &len, datacsum);
if (ret < 0)
goto out;
cur += len;
}
key.objectid = ino;
key.type = BTRFS_INODE_ITEM_KEY;
key.offset = 0;
ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
if (ret) {
ret = (ret > 0 ? -ENOENT : ret);
goto out;
}
btrfs_set_stack_inode_size(&buf, cfg->num_bytes);
write_extent_buffer(path->nodes[0], &buf,
btrfs_item_ptr_offset(path->nodes[0], path->slots[0]),
sizeof(buf));
out:
free_extent_cache_tree(&used_tmp);
btrfs_free_path(path);
btrfs_commit_transaction(trans, root);
return ret;
}
static struct btrfs_root * link_subvol(struct btrfs_root *root,
const char *base, u64 root_objectid)
{