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Btrfs: add snapshot/subvolume destroy ioctl

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This patch adds snapshot/subvolume destroy ioctl.  A subvolume that isn't being
used and doesn't contains links to other subvolumes can be destroyed.

Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
This commit is contained in:
Yan, Zheng
2009-09-21 16:00:26 -04:00
committed by Chris Mason
parent 4df27c4d5c
commit 76dda93c6a
12 changed files with 610 additions and 238 deletions
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134
fs/btrfs/inode.c
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@@ -3089,6 +3089,11 @@ void btrfs_delete_inode(struct inode *inode)
}
btrfs_wait_ordered_range(inode, 0, (u64)-1);
if (inode->i_nlink > 0) {
BUG_ON(btrfs_root_refs(&root->root_item) != 0);
goto no_delete;
}
btrfs_i_size_write(inode, 0);
trans = btrfs_join_transaction(root, 1);
@@ -3225,11 +3230,13 @@ static void inode_tree_add(struct inode *inode)
struct btrfs_inode *entry;
struct rb_node **p;
struct rb_node *parent;
again:
p = &root->inode_tree.rb_node;
parent = NULL;
if (hlist_unhashed(&inode->i_hash))
return;
spin_lock(&root->inode_lock);
while (*p) {
parent = *p;
@@ -3256,13 +3263,87 @@ again:
static void inode_tree_del(struct inode *inode)
{
struct btrfs_root *root = BTRFS_I(inode)->root;
int empty = 0;
spin_lock(&root->inode_lock);
if (!RB_EMPTY_NODE(&BTRFS_I(inode)->rb_node)) {
rb_erase(&BTRFS_I(inode)->rb_node, &root->inode_tree);
RB_CLEAR_NODE(&BTRFS_I(inode)->rb_node);
empty = RB_EMPTY_ROOT(&root->inode_tree);
}
spin_unlock(&root->inode_lock);
if (empty && btrfs_root_refs(&root->root_item) == 0) {
synchronize_srcu(&root->fs_info->subvol_srcu);
spin_lock(&root->inode_lock);
empty = RB_EMPTY_ROOT(&root->inode_tree);
spin_unlock(&root->inode_lock);
if (empty)
btrfs_add_dead_root(root);
}
}
int btrfs_invalidate_inodes(struct btrfs_root *root)
{
struct rb_node *node;
struct rb_node *prev;
struct btrfs_inode *entry;
struct inode *inode;
u64 objectid = 0;
WARN_ON(btrfs_root_refs(&root->root_item) != 0);
spin_lock(&root->inode_lock);
again:
node = root->inode_tree.rb_node;
prev = NULL;
while (node) {
prev = node;
entry = rb_entry(node, struct btrfs_inode, rb_node);
if (objectid < entry->vfs_inode.i_ino)
node = node->rb_left;
else if (objectid > entry->vfs_inode.i_ino)
node = node->rb_right;
else
break;
}
if (!node) {
while (prev) {
entry = rb_entry(prev, struct btrfs_inode, rb_node);
if (objectid <= entry->vfs_inode.i_ino) {
node = prev;
break;
}
prev = rb_next(prev);
}
}
while (node) {
entry = rb_entry(node, struct btrfs_inode, rb_node);
objectid = entry->vfs_inode.i_ino + 1;
inode = igrab(&entry->vfs_inode);
if (inode) {
spin_unlock(&root->inode_lock);
if (atomic_read(&inode->i_count) > 1)
d_prune_aliases(inode);
/*
* btrfs_drop_inode will remove it from
* the inode cache when its usage count
* hits zero.
*/
iput(inode);
cond_resched();
spin_lock(&root->inode_lock);
goto again;
}
if (cond_resched_lock(&root->inode_lock))
goto again;
node = rb_next(node);
}
spin_unlock(&root->inode_lock);
return 0;
}
static noinline void init_btrfs_i(struct inode *inode)
@@ -3379,8 +3460,11 @@ struct inode *btrfs_lookup_dentry(struct inode *dir, struct dentry *dentry)
struct btrfs_root *root = BTRFS_I(dir)->root;
struct btrfs_root *sub_root = root;
struct btrfs_key location;
int index;
int ret;
dentry->d_op = &btrfs_dentry_operations;
if (dentry->d_name.len > BTRFS_NAME_LEN)
return ERR_PTR(-ENAMETOOLONG);
@@ -3399,6 +3483,7 @@ struct inode *btrfs_lookup_dentry(struct inode *dir, struct dentry *dentry)
BUG_ON(location.type != BTRFS_ROOT_ITEM_KEY);
index = srcu_read_lock(&root->fs_info->subvol_srcu);
ret = fixup_tree_root_location(root, dir, dentry,
&location, &sub_root);
if (ret < 0) {
@@ -3409,9 +3494,24 @@ struct inode *btrfs_lookup_dentry(struct inode *dir, struct dentry *dentry)
} else {
inode = btrfs_iget(dir->i_sb, &location, sub_root);
}
srcu_read_unlock(&root->fs_info->subvol_srcu, index);
return inode;
}
static int btrfs_dentry_delete(struct dentry *dentry)
{
struct btrfs_root *root;
if (!dentry->d_inode)
return 0;
root = BTRFS_I(dentry->d_inode)->root;
if (btrfs_root_refs(&root->root_item) == 0)
return 1;
return 0;
}
static struct dentry *btrfs_lookup(struct inode *dir, struct dentry *dentry,
struct nameidata *nd)
{
@@ -4773,11 +4873,11 @@ out:
* create a new subvolume directory/inode (helper for the ioctl).
*/
int btrfs_create_subvol_root(struct btrfs_trans_handle *trans,
struct btrfs_root *new_root, struct dentry *dentry,
struct btrfs_root *new_root,
u64 new_dirid, u64 alloc_hint)
{
struct inode *inode;
int error;
int err;
u64 index = 0;
inode = btrfs_new_inode(trans, new_root, NULL, "..", 2, new_dirid,
@@ -4790,11 +4890,10 @@ int btrfs_create_subvol_root(struct btrfs_trans_handle *trans,
inode->i_nlink = 1;
btrfs_i_size_write(inode, 0);
error = btrfs_update_inode(trans, new_root, inode);
if (error)
return error;
err = btrfs_update_inode(trans, new_root, inode);
BUG_ON(err);
d_instantiate(dentry, inode);
iput(inode);
return 0;
}
@@ -4872,6 +4971,16 @@ void btrfs_destroy_inode(struct inode *inode)
kmem_cache_free(btrfs_inode_cachep, BTRFS_I(inode));
}
void btrfs_drop_inode(struct inode *inode)
{
struct btrfs_root *root = BTRFS_I(inode)->root;
if (inode->i_nlink > 0 && btrfs_root_refs(&root->root_item) == 0)
generic_delete_inode(inode);
else
generic_drop_inode(inode);
}
static void init_once(void *foo)
{
struct btrfs_inode *ei = (struct btrfs_inode *) foo;
@@ -4973,6 +5082,10 @@ static int btrfs_rename(struct inode *old_dir, struct dentry *old_dentry,
old_inode->i_size > BTRFS_ORDERED_OPERATIONS_FLUSH_LIMIT)
filemap_flush(old_inode->i_mapping);
/* close the racy window with snapshot create/destroy ioctl */
if (old_inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)
down_read(&root->fs_info->subvol_sem);
trans = btrfs_start_transaction(root, 1);
if (dest != root)
@@ -5062,6 +5175,8 @@ static int btrfs_rename(struct inode *old_dir, struct dentry *old_dentry,
btrfs_end_transaction_throttle(trans, root);
if (old_inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)
up_read(&root->fs_info->subvol_sem);
return ret;
}
@@ -5420,6 +5535,7 @@ static struct inode_operations btrfs_dir_ro_inode_operations = {
.lookup = btrfs_lookup,
.permission = btrfs_permission,
};
static struct file_operations btrfs_dir_file_operations = {
.llseek = generic_file_llseek,
.read = generic_read_dir,
@@ -5506,3 +5622,7 @@ static struct inode_operations btrfs_symlink_inode_operations = {
.listxattr = btrfs_listxattr,
.removexattr = btrfs_removexattr,
};
struct dentry_operations btrfs_dentry_operations = {
.d_delete = btrfs_dentry_delete,
};