Btrfs: add snapshot/subvolume destroy ioctl

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>

1 files changed, 9 insertions, 3 deletions

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 6ade48b227e9..bc57e236ac64 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -839,9 +839,7 @@ struct btrfs_fs_info {
         struct mutex transaction_kthread_mutex;
         struct mutex cleaner_mutex;
         struct mutex chunk_mutex;
-        struct mutex drop_mutex;
         struct mutex volume_mutex;
-        struct mutex tree_reloc_mutex;
         /*
          * this protects the ordered operations list only while we are
          * processing all of the entries on it.  This way we make
@@ -852,6 +850,10 @@ struct btrfs_fs_info {
         struct mutex ordered_operations_mutex;
         struct rw_semaphore extent_commit_sem;
 
+        struct rw_semaphore subvol_sem;
+
+        struct srcu_struct subvol_srcu;
+
         struct list_head trans_list;
         struct list_head hashers;
         struct list_head dead_roots;
@@ -2142,6 +2144,7 @@ int btrfs_find_last_root(struct btrfs_root *root, u64 objectid, struct
 int btrfs_search_root(struct btrfs_root *root, u64 search_start,
                       u64 *found_objectid);
 int btrfs_find_dead_roots(struct btrfs_root *root, u64 objectid);
+int btrfs_find_orphan_roots(struct btrfs_root *tree_root);
 int btrfs_set_root_node(struct btrfs_root_item *item,
                         struct extent_buffer *node);
 /* dir-item.c */
@@ -2273,7 +2276,7 @@ int btrfs_set_extent_delalloc(struct inode *inode, u64 start, u64 end);
 int btrfs_writepages(struct address_space *mapping,
                      struct writeback_control *wbc);
 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);
 int btrfs_merge_bio_hook(struct page *page, unsigned long offset,
                          size_t size, struct bio *bio, unsigned long bio_flags);
@@ -2289,6 +2292,7 @@ int btrfs_write_inode(struct inode *inode, int wait);
 void btrfs_dirty_inode(struct inode *inode);
 struct inode *btrfs_alloc_inode(struct super_block *sb);
 void btrfs_destroy_inode(struct inode *inode);
+void btrfs_drop_inode(struct inode *inode);
 int btrfs_init_cachep(void);
 void btrfs_destroy_cachep(void);
 long btrfs_ioctl_trans_end(struct file *file);
@@ -2306,6 +2310,8 @@ int btrfs_orphan_add(struct btrfs_trans_handle *trans, struct inode *inode);
 int btrfs_orphan_del(struct btrfs_trans_handle *trans, struct inode *inode);
 void btrfs_orphan_cleanup(struct btrfs_root *root);
 int btrfs_cont_expand(struct inode *inode, loff_t size);
+int btrfs_invalidate_inodes(struct btrfs_root *root);
+extern struct dentry_operations btrfs_dentry_operations;
 
 /* ioctl.c */
 long btrfs_ioctl(struct file *file, unsigned int cmd, unsigned long arg);