Btrfs: subvolumes
Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/TODO b/fs/btrfs/TODO
index 73d4b84..4cd11a1 100644
--- a/fs/btrfs/TODO
+++ b/fs/btrfs/TODO
@@ -8,6 +8,7 @@
* Check compat and incompat flags on the inode
* Add virtual filesystems, mountable snapshots
* Get rid of struct ctree_path, limiting tree levels held at one time
+* EEXIST for dirs instead of hash overflow
* Release
* Do real tree locking
* Add extent mirroring (backup copies of blocks)
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 760fdc9..ff69162 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -301,6 +301,12 @@
int ret = 0;
printk("read_fs_root looking for %Lu %Lu %u\n", location->objectid, location->offset, location->flags);
+ root = radix_tree_lookup(&fs_info->fs_roots_radix,
+ (unsigned long)location->objectid);
+ if (root) {
+printk("found %p in cache\n", root);
+ return root;
+ }
root = kmalloc(sizeof(*root), GFP_NOFS);
if (!root) {
printk("failed1\n");
@@ -349,7 +355,8 @@
insert:
printk("inserting %p\n", root);
root->ref_cows = 1;
- ret = radix_tree_insert(&fs_info->fs_roots_radix, (unsigned long)root,
+ ret = radix_tree_insert(&fs_info->fs_roots_radix,
+ (unsigned long)root->root_key.objectid,
root);
if (ret) {
printk("radix_tree_insert gives us %d\n", ret);
@@ -460,6 +467,20 @@
return 0;
}
+static int free_fs_root(struct btrfs_fs_info *fs_info, struct btrfs_root *root)
+{
+ radix_tree_delete(&fs_info->fs_roots_radix,
+ (unsigned long)root->root_key.objectid);
+ if (root->inode)
+ iput(root->inode);
+ if (root->node)
+ brelse(root->node);
+ if (root->commit_root)
+ brelse(root->commit_root);
+ kfree(root);
+ return 0;
+}
+
int del_fs_roots(struct btrfs_fs_info *fs_info)
{
int ret;
@@ -472,19 +493,8 @@
ARRAY_SIZE(gang));
if (!ret)
break;
- for (i = 0; i < ret; i++) {
- radix_tree_delete(&fs_info->fs_roots_radix,
- (unsigned long)gang[i]);
- if (gang[i]->inode)
- iput(gang[i]->inode);
- else
- printk("no inode for root %p\n", gang[i]);
- if (gang[i]->node)
- brelse(gang[i]->node);
- if (gang[i]->commit_root)
- brelse(gang[i]->commit_root);
- kfree(gang[i]);
- }
+ for (i = 0; i < ret; i++)
+ free_fs_root(fs_info, gang[i]);
}
return 0;
}
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index b93d790..84abdde 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -495,10 +495,6 @@
return ERR_PTR(-EACCES);
if (inode->i_state & I_NEW) {
if (sub_root != root) {
- ret = radix_tree_insert(
- &root->fs_info->fs_roots_radix,
- (unsigned long)sub_root,
- sub_root);
printk("adding new root for inode %lu root %p (found %p)\n", inode->i_ino, sub_root, BTRFS_I(inode)->root);
igrab(inode);
sub_root->inode = inode;
@@ -723,22 +719,19 @@
}
static struct inode *btrfs_new_inode(struct btrfs_trans_handle *trans,
- struct inode *dir, int mode)
+ struct btrfs_root *root,
+ u64 objectid, int mode)
{
struct inode *inode;
struct btrfs_inode_item inode_item;
- struct btrfs_root *root = BTRFS_I(dir)->root;
struct btrfs_key *location;
int ret;
- u64 objectid;
- inode = new_inode(dir->i_sb);
+ inode = new_inode(root->fs_info->sb);
if (!inode)
return ERR_PTR(-ENOMEM);
- BTRFS_I(inode)->root = BTRFS_I(dir)->root;
- ret = btrfs_find_free_objectid(trans, root, dir->i_ino, &objectid);
- BUG_ON(ret);
+ BTRFS_I(inode)->root = root;
inode->i_uid = current->fsuid;
inode->i_gid = current->fsgid;
@@ -804,10 +797,18 @@
struct inode *inode;
int err;
int drop_inode = 0;
+ u64 objectid;
mutex_lock(&root->fs_info->fs_mutex);
trans = btrfs_start_transaction(root, 1);
- inode = btrfs_new_inode(trans, dir, mode);
+
+ err = btrfs_find_free_objectid(trans, root, dir->i_ino, &objectid);
+ if (err) {
+ err = -ENOSPC;
+ goto out_unlock;
+ }
+
+ inode = btrfs_new_inode(trans, root, objectid, mode);
err = PTR_ERR(inode);
if (IS_ERR(inode))
goto out_unlock;
@@ -833,9 +834,9 @@
}
static int btrfs_make_empty_dir(struct btrfs_trans_handle *trans,
- struct inode *inode, struct inode *dir)
+ struct btrfs_root *root,
+ u64 objectid, u64 dirid)
{
- struct btrfs_root *root = BTRFS_I(dir)->root;
int ret;
char buf[2];
struct btrfs_key key;
@@ -843,22 +844,20 @@
buf[0] = '.';
buf[1] = '.';
- key.objectid = inode->i_ino;
+ key.objectid = objectid;
key.offset = 0;
key.flags = 0;
btrfs_set_key_type(&key, BTRFS_INODE_ITEM_KEY);
- ret = btrfs_insert_dir_item(trans, root, buf, 1, inode->i_ino,
+ ret = btrfs_insert_dir_item(trans, root, buf, 1, objectid,
&key, 1);
if (ret)
goto error;
- key.objectid = dir->i_ino;
- ret = btrfs_insert_dir_item(trans, root, buf, 2, inode->i_ino,
+ key.objectid = dirid;
+ ret = btrfs_insert_dir_item(trans, root, buf, 2, objectid,
&key, 1);
if (ret)
goto error;
- inode->i_size = 6;
- ret = btrfs_update_inode(trans, root, inode);
error:
return ret;
}
@@ -870,6 +869,7 @@
struct btrfs_root *root = BTRFS_I(dir)->root;
int err = 0;
int drop_on_err = 0;
+ u64 objectid;
mutex_lock(&root->fs_info->fs_mutex);
trans = btrfs_start_transaction(root, 1);
@@ -877,7 +877,14 @@
err = PTR_ERR(trans);
goto out_unlock;
}
- inode = btrfs_new_inode(trans, dir, S_IFDIR | mode);
+
+ err = btrfs_find_free_objectid(trans, root, dir->i_ino, &objectid);
+ if (err) {
+ err = -ENOSPC;
+ goto out_unlock;
+ }
+
+ inode = btrfs_new_inode(trans, root, objectid, S_IFDIR | mode);
if (IS_ERR(inode)) {
err = PTR_ERR(inode);
goto out_fail;
@@ -886,7 +893,12 @@
inode->i_op = &btrfs_dir_inode_operations;
inode->i_fop = &btrfs_dir_file_operations;
- err = btrfs_make_empty_dir(trans, inode, dir);
+ err = btrfs_make_empty_dir(trans, root, inode->i_ino, dir->i_ino);
+ if (err)
+ goto out_fail;
+
+ inode->i_size = 6;
+ err = btrfs_update_inode(trans, root, inode);
if (err)
goto out_fail;
err = btrfs_add_link(trans, dentry, inode);
@@ -1666,6 +1678,102 @@
return retval;
}
+static int create_subvol(struct btrfs_root *root, char *name, int namelen)
+{
+ struct btrfs_trans_handle *trans;
+ struct btrfs_key key;
+ struct btrfs_root_item root_item;
+ struct btrfs_inode_item *inode_item;
+ struct buffer_head *subvol;
+ struct btrfs_leaf *leaf;
+ struct btrfs_root *new_root;
+ struct inode *inode;
+ int ret;
+ u64 objectid;
+ u64 new_dirid = BTRFS_FIRST_FREE_OBJECTID;
+
+ mutex_lock(&root->fs_info->fs_mutex);
+ trans = btrfs_start_transaction(root, 1);
+ BUG_ON(!trans);
+
+ subvol = btrfs_alloc_free_block(trans, root);
+ leaf = btrfs_buffer_leaf(subvol);
+ btrfs_set_header_nritems(&leaf->header, 0);
+ btrfs_set_header_level(&leaf->header, 0);
+ btrfs_set_header_blocknr(&leaf->header, subvol->b_blocknr);
+ btrfs_set_header_generation(&leaf->header, trans->transid);
+ memcpy(leaf->header.fsid, root->fs_info->disk_super->fsid,
+ sizeof(leaf->header.fsid));
+
+ inode_item = &root_item.inode;
+ memset(inode_item, 0, sizeof(*inode_item));
+ btrfs_set_inode_generation(inode_item, 1);
+ btrfs_set_inode_size(inode_item, 3);
+ btrfs_set_inode_nlink(inode_item, 1);
+ btrfs_set_inode_nblocks(inode_item, 1);
+ btrfs_set_inode_mode(inode_item, S_IFDIR | 0755);
+
+ btrfs_set_root_blocknr(&root_item, subvol->b_blocknr);
+ btrfs_set_root_refs(&root_item, 1);
+
+ mark_buffer_dirty(subvol);
+ brelse(subvol);
+ subvol = NULL;
+
+ ret = btrfs_find_free_objectid(trans, root->fs_info->tree_root,
+ 0, &objectid);
+ BUG_ON(ret);
+
+ btrfs_set_root_dirid(&root_item, new_dirid);
+
+ key.objectid = objectid;
+ key.offset = 1;
+ key.flags = 0;
+ btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY);
+ ret = btrfs_insert_root(trans, root->fs_info->tree_root, &key,
+ &root_item);
+ BUG_ON(ret);
+
+ /*
+ * insert the directory item
+ */
+ key.offset = (u64)-1;
+ ret = btrfs_insert_dir_item(trans, root->fs_info->tree_root,
+ name, namelen,
+ root->fs_info->sb->s_root->d_inode->i_ino,
+ &key, 0);
+ BUG_ON(ret);
+
+ ret = btrfs_commit_transaction(trans, root);
+ BUG_ON(ret);
+
+ new_root = btrfs_read_fs_root(root->fs_info, &key);
+ BUG_ON(!new_root);
+
+ trans = btrfs_start_transaction(new_root, 1);
+ BUG_ON(!trans);
+
+ inode = btrfs_new_inode(trans, new_root, new_dirid, S_IFDIR | 0700);
+ inode->i_op = &btrfs_dir_inode_operations;
+ inode->i_fop = &btrfs_dir_file_operations;
+
+ ret = btrfs_make_empty_dir(trans, new_root, new_dirid, new_dirid);
+ BUG_ON(ret);
+
+ inode->i_nlink = 1;
+ inode->i_size = 6;
+ ret = btrfs_update_inode(trans, new_root, inode);
+ BUG_ON(ret);
+
+ ret = btrfs_commit_transaction(trans, new_root);
+ BUG_ON(ret);
+
+ iput(inode);
+
+ mutex_unlock(&root->fs_info->fs_mutex);
+ return 0;
+}
+
static int create_snapshot(struct btrfs_root *root, char *name, int namelen)
{
struct btrfs_trans_handle *trans;
@@ -1674,6 +1782,9 @@
int ret;
u64 objectid;
+ if (!root->ref_cows)
+ return -EINVAL;
+
mutex_lock(&root->fs_info->fs_mutex);
trans = btrfs_start_transaction(root, 1);
BUG_ON(!trans);
@@ -1685,7 +1796,6 @@
0, &objectid);
BUG_ON(ret);
- memset(&new_root_item, 0, sizeof(new_root_item));
memcpy(&new_root_item, &root->root_item,
sizeof(new_root_item));
@@ -1728,9 +1838,9 @@
struct btrfs_ioctl_vol_args vol_args;
int ret;
int namelen;
+ struct btrfs_path *path;
+ u64 root_dirid;
- if (!root->ref_cows)
- return -EINVAL;
switch (cmd) {
case BTRFS_IOC_SNAP_CREATE:
if (copy_from_user(&vol_args,
@@ -1740,7 +1850,23 @@
namelen = strlen(vol_args.name);
if (namelen > BTRFS_VOL_NAME_MAX)
return -EINVAL;
- ret = create_snapshot(root, vol_args.name, namelen);
+ path = btrfs_alloc_path();
+ if (!path)
+ return -ENOMEM;
+ root_dirid = btrfs_root_dirid(
+ &root->fs_info->tree_root->root_item);
+ mutex_lock(&root->fs_info->fs_mutex);
+ ret = btrfs_lookup_dir_item(NULL, root->fs_info->tree_root,
+ path, root_dirid,
+ vol_args.name, namelen, 0);
+ mutex_unlock(&root->fs_info->fs_mutex);
+ if (ret == 0)
+ return -EEXIST;
+
+ if (root == root->fs_info->tree_root)
+ ret = create_subvol(root, vol_args.name, namelen);
+ else
+ ret = create_snapshot(root, vol_args.name, namelen);
WARN_ON(ret);
break;
default:
diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index f64c172..e15a072 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -64,7 +64,8 @@
if (root != root->fs_info->tree_root && root->last_trans <
running_trans_id) {
radix_tree_tag_set(&root->fs_info->fs_roots_radix,
- (unsigned long)root, BTRFS_ROOT_TRANS_TAG);
+ (unsigned long)root->root_key.objectid,
+ BTRFS_ROOT_TRANS_TAG);
root->commit_root = root->node;
get_bh(root->node);
}
@@ -171,8 +172,9 @@
break;
for (i = 0; i < ret; i++) {
root = gang[i];
- radix_tree_tag_clear(radix, (unsigned long)root,
- BTRFS_ROOT_TRANS_TAG);
+ radix_tree_tag_clear(radix,
+ (unsigned long)root->root_key.objectid,
+ BTRFS_ROOT_TRANS_TAG);
if (root->commit_root == root->node) {
WARN_ON(root->node->b_blocknr !=
btrfs_root_blocknr(&root->root_item));