On Tue, May 14, 2013 at 11:36:55AM +0200, Stefan Behrens wrote:
> This tree is not created by mkfs.btrfs. Therefore when a filesystem
> is mounted writable and the UUID tree does not exist, this tree is
> created if required. The tree is also added to the fs_info structure
> and initialized, but this commit does not yet read or write UUID tree
> elements.
>
> Signed-off-by: Stefan Behrens <sbehr...@giantdisaster.de>
> ---
> fs/btrfs/ctree.h | 1 +
> fs/btrfs/disk-io.c | 40 +++++++++++++++++++++++++++++++++++++++-
> fs/btrfs/volumes.c | 27 +++++++++++++++++++++++++++
> fs/btrfs/volumes.h | 1 +
> 4 files changed, 68 insertions(+), 1 deletion(-)
>
> diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
> index ca9149a..6f9d760 100644
> --- a/fs/btrfs/ctree.h
> +++ b/fs/btrfs/ctree.h
> @@ -1305,6 +1305,7 @@ struct btrfs_fs_info {
> struct btrfs_root *fs_root;
> struct btrfs_root *csum_root;
> struct btrfs_root *quota_root;
> + struct btrfs_root *uuid_root;
>
> /* the log root tree is a directory of all the other log roots */
> struct btrfs_root *log_root_tree;
> diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
> index 4904d7f..3c2bf74 100644
> --- a/fs/btrfs/disk-io.c
> +++ b/fs/btrfs/disk-io.c
> @@ -1499,6 +1499,9 @@ struct btrfs_root *btrfs_read_fs_root_no_name(struct
> btrfs_fs_info *fs_info,
> if (location->objectid == BTRFS_QUOTA_TREE_OBJECTID)
> return fs_info->quota_root ? fs_info->quota_root :
> ERR_PTR(-ENOENT);
> + if (location->objectid == BTRFS_UUID_TREE_OBJECTID)
> + return fs_info->uuid_root ? fs_info->uuid_root :
> + ERR_PTR(-ENOENT);
> again:
> spin_lock(&fs_info->fs_roots_radix_lock);
> root = radix_tree_lookup(&fs_info->fs_roots_radix,
> @@ -1955,6 +1958,10 @@ static void free_root_pointers(struct btrfs_fs_info
> *info, int chunk_root)
> free_extent_buffer(info->quota_root->node);
> free_extent_buffer(info->quota_root->commit_root);
> }
> + if (info->uuid_root) {
> + free_extent_buffer(info->uuid_root->node);
> + free_extent_buffer(info->uuid_root->commit_root);
> + }
>
> info->tree_root->node = NULL;
> info->tree_root->commit_root = NULL;
> @@ -1968,6 +1975,10 @@ static void free_root_pointers(struct btrfs_fs_info
> *info, int chunk_root)
> info->quota_root->node = NULL;
> info->quota_root->commit_root = NULL;
> }
> + if (info->uuid_root) {
> + info->uuid_root->node = NULL;
> + info->uuid_root->commit_root = NULL;
> + }
>
> if (chunk_root) {
> free_extent_buffer(info->chunk_root->node);
> @@ -2029,11 +2040,13 @@ int open_ctree(struct super_block *sb,
> struct btrfs_root *chunk_root;
> struct btrfs_root *dev_root;
> struct btrfs_root *quota_root;
> + struct btrfs_root *uuid_root;
> struct btrfs_root *log_tree_root;
> int ret;
> int err = -EINVAL;
> int num_backups_tried = 0;
> int backup_index = 0;
> + bool create_uuid_tree = false;
>
> tree_root = fs_info->tree_root = btrfs_alloc_root(fs_info);
> extent_root = fs_info->extent_root = btrfs_alloc_root(fs_info);
> @@ -2041,9 +2054,10 @@ int open_ctree(struct super_block *sb,
> chunk_root = fs_info->chunk_root = btrfs_alloc_root(fs_info);
> dev_root = fs_info->dev_root = btrfs_alloc_root(fs_info);
> quota_root = fs_info->quota_root = btrfs_alloc_root(fs_info);
> + uuid_root = fs_info->uuid_root = btrfs_alloc_root(fs_info);
>
> if (!tree_root || !extent_root || !csum_root ||
> - !chunk_root || !dev_root || !quota_root) {
> + !chunk_root || !dev_root || !quota_root || !uuid_root) {
> err = -ENOMEM;
> goto fail;
> }
> @@ -2604,6 +2618,19 @@ retry_root_backup:
> fs_info->pending_quota_state = 1;
> }
>
> + ret = find_and_setup_root(tree_root, fs_info,
> + BTRFS_UUID_TREE_OBJECTID, uuid_root);
> + if (ret) {
> + if (ret != -ENOENT)
> + goto recovery_tree_root;
> +
> + kfree(uuid_root);
> + uuid_root = fs_info->uuid_root = NULL;
> + create_uuid_tree = true;
> + } else {
> + uuid_root->track_dirty = 1;
> + }
> +
> fs_info->generation = generation;
> fs_info->last_trans_committed = generation;
>
> @@ -2788,6 +2815,17 @@ retry_root_backup:
> return ret;
> }
>
> + if (create_uuid_tree) {
> + pr_info("btrfs: creating UUID tree\n");
> + ret = btrfs_create_uuid_tree(fs_info);
> + if (ret) {
> + pr_warn("btrfs: failed to create the UUID tree %d\n",
> + ret);
> + close_ctree(tree_root);
> + return ret;
> + }
> + }
> +
> return 0;
>
> fail_qgroup:
> diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
> index a191bac..e6f5b88 100644
> --- a/fs/btrfs/volumes.c
> +++ b/fs/btrfs/volumes.c
> @@ -3427,6 +3427,33 @@ int btrfs_cancel_balance(struct btrfs_fs_info *fs_info)
> return 0;
> }
>
> +int btrfs_create_uuid_tree(struct btrfs_fs_info *fs_info)
> +{
> + struct btrfs_trans_handle *trans;
> + struct btrfs_root *tree_root = fs_info->tree_root;
> + struct btrfs_root *uuid_root;
> +
> + /*
> + * 1 - root node
> + * 1 - root item
> + */
> + trans = btrfs_start_transaction(tree_root, 2);
> + if (IS_ERR(trans))
> + return PTR_ERR(trans);
> +
> + uuid_root = btrfs_create_tree(trans, fs_info,
> + BTRFS_UUID_TREE_OBJECTID);
> + if (IS_ERR(uuid_root)) {
> + btrfs_abort_transaction(trans, tree_root,
> + PTR_ERR(uuid_root));
> + return PTR_ERR(uuid_root);
> + }
> +
> + fs_info->uuid_root = uuid_root;
> + uuid_root->track_dirty = 1;
btrfs_create_tree() has already set track_dirty.
thanks,
liubo
> +
> + return btrfs_commit_transaction(trans, tree_root);
> +}
> /*
> * shrinking a device means finding all of the device extents past
> * the new size, and then following the back refs to the chunks.
> diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
> index 845ccbb..3479532 100644
> --- a/fs/btrfs/volumes.h
> +++ b/fs/btrfs/volumes.h
> @@ -295,6 +295,7 @@ int btrfs_resume_balance_async(struct btrfs_fs_info
> *fs_info);
> int btrfs_recover_balance(struct btrfs_fs_info *fs_info);
> int btrfs_pause_balance(struct btrfs_fs_info *fs_info);
> int btrfs_cancel_balance(struct btrfs_fs_info *fs_info);
> +int btrfs_create_uuid_tree(struct btrfs_fs_info *fs_info);
> int btrfs_chunk_readonly(struct btrfs_root *root, u64 chunk_offset);
> int find_free_dev_extent(struct btrfs_device *device, u64 num_bytes,
> u64 *start, u64 *max_avail);
> --
> 1.8.2.2
>
> --
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