Links to snapshots/subvols are similar to normal directories.
The main difference is snapshots/subvols use root back & forward
references instead of inode back references. This patch adds code
that handles back & forward references for rename and rmdir.
Signed-off-by: Yan Zheng <zheng.yan@xxxxxxxxxx>
---
diff -urp 2/fs/btrfs/ctree.h 3/fs/btrfs/ctree.h
--- 2/fs/btrfs/ctree.h 2009-08-24 10:36:46.212099000 +0800
+++ 3/fs/btrfs/ctree.h 2009-08-24 10:38:34.280386024 +0800
@@ -2102,12 +2102,15 @@ int btrfs_drop_subtree(struct btrfs_tran
struct extent_buffer *parent);
/* root-item.c */
int btrfs_find_root_ref(struct btrfs_root *tree_root,
- struct btrfs_path *path,
- u64 root_id, u64 ref_id);
+ struct btrfs_path *path,
+ u64 root_id, u64 ref_id);
int btrfs_add_root_ref(struct btrfs_trans_handle *trans,
struct btrfs_root *tree_root,
- u64 root_id, u8 type, u64 ref_id,
- u64 dirid, u64 sequence,
+ u64 root_id, u64 ref_id, u64 dirid, u64 sequence,
+ const char *name, int name_len);
+int btrfs_del_root_ref(struct btrfs_trans_handle *trans,
+ struct btrfs_root *tree_root,
+ u64 root_id, u64 ref_id, u64 dirid, u64 *sequence,
const char *name, int name_len);
int btrfs_del_root(struct btrfs_trans_handle *trans, struct btrfs_root *root,
struct btrfs_key *key);
@@ -2140,6 +2143,10 @@ btrfs_lookup_dir_index_item(struct btrfs
struct btrfs_path *path, u64 dir,
u64 objectid, const char *name, int name_len,
int mod);
+struct btrfs_dir_item *
+btrfs_search_dir_index_item(struct btrfs_root *root,
+ struct btrfs_path *path, u64 dirid,
+ const char *name, int name_len);
struct btrfs_dir_item *btrfs_match_dir_item_name(struct btrfs_root *root,
struct btrfs_path *path,
const char *name, int name_len);
@@ -2234,6 +2241,10 @@ int btrfs_unlink_inode(struct btrfs_tran
int btrfs_add_link(struct btrfs_trans_handle *trans,
struct inode *parent_inode, struct inode *inode,
const char *name, int name_len, int add_backref, u64 index);
+int btrfs_unlink_subvol(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root,
+ struct inode *dir, struct inode *inode,
+ const char *name, int name_len);
int btrfs_truncate_inode_items(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct inode *inode, u64 new_size,
diff -urp 2/fs/btrfs/dir-item.c 3/fs/btrfs/dir-item.c
--- 2/fs/btrfs/dir-item.c 2009-08-24 10:36:46.213099000 +0800
+++ 3/fs/btrfs/dir-item.c 2009-08-24 10:38:34.281099463 +0800
@@ -281,6 +281,53 @@ btrfs_lookup_dir_index_item(struct btrfs
return btrfs_match_dir_item_name(root, path, name, name_len);
}
+struct btrfs_dir_item *
+btrfs_search_dir_index_item(struct btrfs_root *root,
+ struct btrfs_path *path, u64 dirid,
+ const char *name, int name_len)
+{
+ struct extent_buffer *leaf;
+ struct btrfs_dir_item *di;
+ struct btrfs_key key;
+ u32 nritems;
+ int ret;
+
+ key.objectid = dirid;
+ key.type = BTRFS_DIR_INDEX_KEY;
+ key.offset = 0;
+
+ ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
+ if (ret < 0)
+ return ERR_PTR(ret);
+
+ leaf = path->nodes[0];
+ nritems = btrfs_header_nritems(leaf);
+
+ while (1) {
+ if (path->slots[0] >= nritems) {
+ ret = btrfs_next_leaf(root, path);
+ if (ret < 0)
+ return ERR_PTR(ret);
+ if (ret > 0)
+ break;
+ leaf = path->nodes[0];
+ nritems = btrfs_header_nritems(leaf);
+ continue;
+ }
+
+ btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
+ if (key.objectid != dirid || key.type != BTRFS_DIR_INDEX_KEY)
+ break;
+
+ di = btrfs_match_dir_item_name(root, path, name, name_len);
+ if (di)
+ return di;
+
+ path->slots[0]++;
+ }
+ return NULL;
+}
+
struct btrfs_dir_item *btrfs_lookup_xattr(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_path *path, u64 dir,
diff -urp 2/fs/btrfs/inode.c 3/fs/btrfs/inode.c
--- 2/fs/btrfs/inode.c 2009-08-24 10:36:46.217098000 +0800
+++ 3/fs/btrfs/inode.c 2009-08-24 10:38:34.284098975 +0800
@@ -2356,6 +2356,72 @@ static int btrfs_unlink(struct inode *di
return ret;
}
+int btrfs_unlink_subvol(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root,
+ struct inode *dir, struct inode *inode,
+ const char *name, int name_len)
+{
+ struct btrfs_path *path;
+ struct extent_buffer *leaf;
+ struct btrfs_dir_item *di;
+ struct btrfs_key key;
+ u64 index;
+ int ret;
+
+ WARN_ON(root == BTRFS_I(inode)->root);
+ path = btrfs_alloc_path();
+ if (!path)
+ return -ENOMEM;
+
+ di = btrfs_lookup_dir_item(trans, root, path, dir->i_ino,
+ name, name_len, -1);
+ BUG_ON(!di || IS_ERR(di));
+
+ leaf = path->nodes[0];
+ btrfs_dir_item_key_to_cpu(leaf, di, &key);
+ WARN_ON(key.type != BTRFS_ROOT_ITEM_KEY ||
+ key.objectid != BTRFS_I(inode)->root->root_key.objectid);
+ ret = btrfs_delete_one_dir_name(trans, root, path, di);
+ BUG_ON(ret);
+ btrfs_release_path(root, path);
+
+ ret = btrfs_del_root_ref(trans, root->fs_info->tree_root,
+ BTRFS_I(inode)->root->root_key.objectid,
+ root->root_key.objectid, dir->i_ino,
+ &index, name, name_len);
+ if (ret < 0) {
+ BUG_ON(ret != -ENOENT);
+ di = btrfs_search_dir_index_item(root, path, dir->i_ino,
+ name, name_len);
+ BUG_ON(!di || IS_ERR(di));
+
+ leaf = path->nodes[0];
+ btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
+ btrfs_release_path(root, path);
+ index = key.offset;
+ }
+
+ di = btrfs_lookup_dir_index_item(trans, root, path, dir->i_ino,
+ index, name, name_len, -1);
+ BUG_ON(!di || IS_ERR(di));
+
+ btrfs_dir_item_key_to_cpu(leaf, di, &key);
+ WARN_ON(key.type != BTRFS_ROOT_ITEM_KEY ||
+ key.objectid != BTRFS_I(inode)->root->root_key.objectid);
+ ret = btrfs_delete_one_dir_name(trans, root, path, di);
+ BUG_ON(ret);
+ btrfs_release_path(root, path);
+
+ btrfs_i_size_write(dir, dir->i_size - name_len * 2);
+ dir->i_mtime = dir->i_ctime = CURRENT_TIME;
+ ret = btrfs_update_inode(trans, root, dir);
+ BUG_ON(ret);
+ dir->i_sb->s_dirt = 1;
+
+ btrfs_free_path(path);
+ return 0;
+}
+
static int btrfs_rmdir(struct inode *dir, struct dentry *dentry)
{
struct inode *inode = dentry->d_inode;
@@ -2369,25 +2435,30 @@ static int btrfs_rmdir(struct inode *dir
* the FIRST_FREE_OBJECTID check makes sure we don't try to rmdir
* the root of a subvolume or snapshot
*/
- if (inode->i_size > BTRFS_EMPTY_DIR_SIZE ||
- inode->i_ino == BTRFS_FIRST_FREE_OBJECTID) {
+ if (inode->i_size > BTRFS_EMPTY_DIR_SIZE)
return -ENOTEMPTY;
- }
trans = btrfs_start_transaction(root, 1);
btrfs_set_trans_block_group(trans, dir);
+ if (unlikely(inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)) {
+ root->fs_info->last_trans_log_full_commit = trans->transid;
+ err = btrfs_unlink_subvol(trans, root, dir, dentry->d_inode,
+ dentry->d_name.name,
+ dentry->d_name.len);
+ goto out;
+ }
+
err = btrfs_orphan_add(trans, inode);
if (err)
- goto fail_trans;
+ goto out;
/* now the directory is empty */
err = btrfs_unlink_inode(trans, root, dir, dentry->d_inode,
dentry->d_name.name, dentry->d_name.len);
if (!err)
btrfs_i_size_write(inode, 0);
-
-fail_trans:
+out:
nr = trans->blocks_used;
ret = btrfs_end_transaction_throttle(trans, root);
btrfs_btree_balance_dirty(root, nr);
@@ -3674,26 +3745,36 @@ int btrfs_add_link(struct btrfs_trans_ha
struct inode *parent_inode, struct inode *inode,
const char *name, int name_len, int add_backref, u64 index)
{
- int ret;
+ int ret = 0;
struct btrfs_key key;
struct btrfs_root *root = BTRFS_I(parent_inode)->root;
- key.objectid = inode->i_ino;
- btrfs_set_key_type(&key, BTRFS_INODE_ITEM_KEY);
- key.offset = 0;
+ if (unlikely(inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)) {
+ memcpy(&key, &BTRFS_I(inode)->root->root_key, sizeof(key));
+ key.offset = (u64)-1;
+ } else {
+ key.objectid = inode->i_ino;
+ btrfs_set_key_type(&key, BTRFS_INODE_ITEM_KEY);
+ key.offset = 0;
+ }
+
+ if (unlikely(inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)) {
+ ret = btrfs_add_root_ref(trans, root->fs_info->tree_root,
+ key.objectid, root->root_key.objectid,
+ parent_inode->i_ino,
+ index, name, name_len);
+ } else if (add_backref) {
+ ret = btrfs_insert_inode_ref(trans, root,
+ name, name_len, inode->i_ino,
+ parent_inode->i_ino, index);
+ }
- ret = btrfs_insert_dir_item(trans, root, name, name_len,
- parent_inode->i_ino,
- &key, btrfs_inode_type(inode),
- index);
if (ret == 0) {
- if (add_backref) {
- ret = btrfs_insert_inode_ref(trans, root,
- name, name_len,
- inode->i_ino,
- parent_inode->i_ino,
- index);
- }
+ ret = btrfs_insert_dir_item(trans, root, name, name_len,
+ parent_inode->i_ino, &key,
+ btrfs_inode_type(inode), index);
+ BUG_ON(ret);
+
btrfs_i_size_write(parent_inode, parent_inode->i_size +
name_len * 2);
parent_inode->i_mtime = parent_inode->i_ctime = CURRENT_TIME;
@@ -4782,20 +4863,12 @@ static int btrfs_rename(struct inode *ol
int ret;
/* we're not allowed to rename between subvolumes */
- if (BTRFS_I(old_inode)->root->root_key.objectid !=
- BTRFS_I(new_dir)->root->root_key.objectid)
+ if (BTRFS_I(old_dir)->root != BTRFS_I(new_dir)->root)
return -EXDEV;
if (S_ISDIR(old_inode->i_mode) && new_inode &&
- new_inode->i_size > BTRFS_EMPTY_DIR_SIZE) {
+ new_inode->i_size > BTRFS_EMPTY_DIR_SIZE)
return -ENOTEMPTY;
- }
-
- /* to rename a snapshot or subvolume, we need to juggle the
- * backrefs. This isn't coded yet
- */
- if (old_inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)
- return -EXDEV;
ret = btrfs_check_metadata_free_space(root);
if (ret)
@@ -4812,6 +4885,11 @@ static int btrfs_rename(struct inode *ol
trans = btrfs_start_transaction(root, 1);
+ /* force full log commit if snapshot or subvolume gets involved. */
+ if (old_inode->i_ino == BTRFS_FIRST_FREE_OBJECTID ||
+ (new_inode && new_inode->i_ino == BTRFS_FIRST_FREE_OBJECTID))
+ root->fs_info->last_trans_log_full_commit = trans->transid;
+
/*
* make sure the inode gets flushed if it is replacing
* something.
@@ -4840,18 +4918,35 @@ static int btrfs_rename(struct inode *ol
if (old_dentry->d_parent != new_dentry->d_parent)
btrfs_record_unlink_dir(trans, old_dir, old_inode, 1);
- ret = btrfs_unlink_inode(trans, root, old_dir, old_dentry->d_inode,
- old_dentry->d_name.name,
- old_dentry->d_name.len);
+ if (unlikely(old_inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)) {
+ ret = btrfs_unlink_subvol(trans, root, old_dir,
+ old_dentry->d_inode,
+ old_dentry->d_name.name,
+ old_dentry->d_name.len);
+ } else {
+ btrfs_inc_nlink(old_dentry->d_inode);
+ ret = btrfs_unlink_inode(trans, root, old_dir,
+ old_dentry->d_inode,
+ old_dentry->d_name.name,
+ old_dentry->d_name.len);
+ }
if (ret)
goto out_fail;
if (new_inode) {
new_inode->i_ctime = CURRENT_TIME;
- ret = btrfs_unlink_inode(trans, root, new_dir,
- new_dentry->d_inode,
- new_dentry->d_name.name,
- new_dentry->d_name.len);
+ if (unlikely(new_inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)) {
+ ret = btrfs_unlink_subvol(trans, root, new_dir,
+ new_dentry->d_inode,
+ new_dentry->d_name.name,
+ new_dentry->d_name.len);
+ WARN_ON(new_inode->i_nlink == 0);
+ } else {
+ ret = btrfs_unlink_inode(trans, root, new_dir,
+ new_dentry->d_inode,
+ new_dentry->d_name.name,
+ new_dentry->d_name.len);
+ }
if (ret)
goto out_fail;
if (new_inode->i_nlink == 0) {
@@ -4859,7 +4954,6 @@ static int btrfs_rename(struct inode *ol
if (ret)
goto out_fail;
}
-
}
ret = btrfs_set_inode_index(new_dir, &index);
if (ret)
diff -urp 2/fs/btrfs/ioctl.c 3/fs/btrfs/ioctl.c
--- 2/fs/btrfs/ioctl.c 2009-08-24 10:36:46.219099000 +0800
+++ 3/fs/btrfs/ioctl.c 2009-08-24 10:38:34.286099535 +0800
@@ -323,18 +323,8 @@ static noinline int create_subvol(struct
ret = btrfs_update_inode(trans, root, dir);
BUG_ON(ret);
- /* add the backref first */
ret = btrfs_add_root_ref(trans, root->fs_info->tree_root,
- objectid, BTRFS_ROOT_BACKREF_KEY,
- root->root_key.objectid,
- dir->i_ino, index, name, namelen);
-
- BUG_ON(ret);
-
- /* now add the forward ref */
- ret = btrfs_add_root_ref(trans, root->fs_info->tree_root,
- root->root_key.objectid, BTRFS_ROOT_REF_KEY,
- objectid,
+ objectid, root->root_key.objectid,
dir->i_ino, index, name, namelen);
BUG_ON(ret);
diff -urp 2/fs/btrfs/root-tree.c 3/fs/btrfs/root-tree.c
--- 2/fs/btrfs/root-tree.c 2009-08-24 10:36:46.220099000 +0800
+++ 3/fs/btrfs/root-tree.c 2009-08-24 10:38:34.287099466 +0800
@@ -278,31 +278,57 @@ out:
return ret;
}
-#if 0 /* this will get used when snapshot deletion is implemented */
int btrfs_del_root_ref(struct btrfs_trans_handle *trans,
struct btrfs_root *tree_root,
- u64 root_id, u8 type, u64 ref_id)
+ u64 root_id, u64 ref_id, u64 dirid, u64 *sequence,
+ const char *name, int name_len)
+
{
+ struct btrfs_path *path;
+ struct btrfs_root_ref *ref;
+ struct extent_buffer *leaf;
struct btrfs_key key;
+ unsigned long ptr;
+ int err = 0;
int ret;
- struct btrfs_path *path;
path = btrfs_alloc_path();
+ if (!path)
+ return -ENOMEM;
key.objectid = root_id;
- key.type = type;
+ key.type = BTRFS_ROOT_BACKREF_KEY;
key.offset = ref_id;
-
+again:
ret = btrfs_search_slot(trans, tree_root, &key, path, -1, 1);
- BUG_ON(ret);
-
- ret = btrfs_del_item(trans, tree_root, path);
- BUG_ON(ret);
+ BUG_ON(ret < 0);
+ if (ret == 0) {
+ leaf = path->nodes[0];
+ ref = btrfs_item_ptr(leaf, path->slots[0],
+ struct btrfs_root_ref);
+
+ WARN_ON(btrfs_root_ref_dirid(leaf, ref) != dirid);
+ WARN_ON(btrfs_root_ref_name_len(leaf, ref) != name_len);
+ ptr = (unsigned long)(ref + 1);
+ WARN_ON(memcmp_extent_buffer(leaf, name, ptr, name_len));
+ *sequence = btrfs_root_ref_sequence(leaf, ref);
+
+ ret = btrfs_del_item(trans, tree_root, path);
+ BUG_ON(ret);
+ } else
+ err = -ENOENT;
+
+ if (key.type == BTRFS_ROOT_BACKREF_KEY) {
+ btrfs_release_path(tree_root, path);
+ key.objectid = ref_id;
+ key.type = BTRFS_ROOT_REF_KEY;
+ key.offset = root_id;
+ goto again;
+ }
btrfs_free_path(path);
- return ret;
+ return err;
}
-#endif
int btrfs_find_root_ref(struct btrfs_root *tree_root,
struct btrfs_path *path,
@@ -319,7 +345,6 @@ int btrfs_find_root_ref(struct btrfs_roo
return ret;
}
-
/*
* add a btrfs_root_ref item. type is either BTRFS_ROOT_REF_KEY
* or BTRFS_ROOT_BACKREF_KEY.
@@ -335,8 +360,7 @@ int btrfs_find_root_ref(struct btrfs_roo
*/
int btrfs_add_root_ref(struct btrfs_trans_handle *trans,
struct btrfs_root *tree_root,
- u64 root_id, u8 type, u64 ref_id,
- u64 dirid, u64 sequence,
+ u64 root_id, u64 ref_id, u64 dirid, u64 sequence,
const char *name, int name_len)
{
struct btrfs_key key;
@@ -346,13 +370,14 @@ int btrfs_add_root_ref(struct btrfs_tran
struct extent_buffer *leaf;
unsigned long ptr;
-
path = btrfs_alloc_path();
+ if (!path)
+ return -ENOMEM;
key.objectid = root_id;
- key.type = type;
+ key.type = BTRFS_ROOT_BACKREF_KEY;
key.offset = ref_id;
-
+again:
ret = btrfs_insert_empty_item(trans, tree_root, path, &key,
sizeof(*ref) + name_len);
BUG_ON(ret);
@@ -366,6 +391,14 @@ int btrfs_add_root_ref(struct btrfs_tran
write_extent_buffer(leaf, name, ptr, name_len);
btrfs_mark_buffer_dirty(leaf);
+ if (key.type == BTRFS_ROOT_BACKREF_KEY) {
+ btrfs_release_path(tree_root, path);
+ key.objectid = ref_id;
+ key.type = BTRFS_ROOT_REF_KEY;
+ key.offset = root_id;
+ goto again;
+ }
+
btrfs_free_path(path);
- return ret;
+ return 0;
}
diff -urp 2/fs/btrfs/transaction.c 3/fs/btrfs/transaction.c
--- 2/fs/btrfs/transaction.c 2009-08-24 10:36:46.248107000 +0800
+++ 3/fs/btrfs/transaction.c 2009-08-24 10:38:34.288098978 +0800
@@ -779,24 +779,14 @@ static noinline int finish_pending_snaps
ret = btrfs_update_inode(trans, parent_root, parent_inode);
BUG_ON(ret);
- /* add the backref first */
ret = btrfs_add_root_ref(trans, parent_root->fs_info->tree_root,
pending->root_key.objectid,
- BTRFS_ROOT_BACKREF_KEY,
parent_root->root_key.objectid,
parent_inode->i_ino, index, pending->name,
namelen);
BUG_ON(ret);
- /* now add the forward ref */
- ret = btrfs_add_root_ref(trans, parent_root->fs_info->tree_root,
- parent_root->root_key.objectid,
- BTRFS_ROOT_REF_KEY,
- pending->root_key.objectid,
- parent_inode->i_ino, index, pending->name,
- namelen);
-
inode = btrfs_lookup_dentry(parent_inode, pending->dentry);
d_instantiate(pending->dentry, inode);
fail:
diff -urp 2/fs/btrfs/tree-log.c 3/fs/btrfs/tree-log.c
--- 2/fs/btrfs/tree-log.c 2009-08-24 10:36:46.248107000 +0800
+++ 3/fs/btrfs/tree-log.c 2009-08-24 10:38:34.290099887 +0800
@@ -2885,6 +2885,11 @@ int btrfs_log_inode_parent(struct btrfs_
if (ret)
goto end_no_trans;
+ if (root != BTRFS_I(inode)->root) {
+ ret = 0;
+ goto end_no_trans;
+ }
+
start_log_trans(trans, root);
ret = btrfs_log_inode(trans, root, inode, inode_only);
@@ -2907,6 +2912,9 @@ int btrfs_log_inode_parent(struct btrfs_
break;
inode = parent->d_inode;
+ if (root != BTRFS_I(inode)->root)
+ break;
+
if (BTRFS_I(inode)->generation >
root->fs_info->last_trans_committed) {
ret = btrfs_log_inode(trans, root, inode, inode_only);
--
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