Btrfs: Add the ability to find and remove dead roots after a crash.

[linux-2.6-block.git] / fs / btrfs / root-tree.c

diff --git a/fs/btrfs/root-tree.c b/fs/btrfs/root-tree.c
index ac0fae7780ff18e8620ca2e98c6639392eeefd75..737e5a38d17eb920fee2bf41e85d30541e5286a6 100644 (file)
--- a/fs/btrfs/root-tree.c
+++ b/fs/btrfs/root-tree.c
@@ -18,6 +18,7 @@
 
 #include <linux/module.h>
 #include "ctree.h"
+#include "transaction.h"
 #include "disk-io.h"
 #include "print-tree.h"
 
@@ -32,7 +33,7 @@ int btrfs_find_last_root(struct btrfs_root *root, u64 objectid,
 
        search_key.objectid = objectid;
        search_key.flags = (u32)-1;
-       search_key.offset = (u32)-1;
+       search_key.offset = (u64)-1;
 
        path = btrfs_alloc_path();
        BUG_ON(!path);
@@ -50,6 +51,7 @@ int btrfs_find_last_root(struct btrfs_root *root, u64 objectid,
        memcpy(item, btrfs_item_ptr(l, slot, struct btrfs_root_item),
                sizeof(*item));
        btrfs_disk_key_to_cpu(key, &l->items[slot].key);
+printk("find last finds key %Lu %u %Lu slot %d search for obj %Lu\n", key->objectid, key->flags, key->offset, slot, objectid);
        ret = 0;
 out:
        btrfs_release_path(root, path);
@@ -93,6 +95,67 @@ int btrfs_insert_root(struct btrfs_trans_handle *trans, struct btrfs_root
        return ret;
 }
 
+int btrfs_find_dead_roots(struct btrfs_root *root)
+{
+       struct btrfs_root *dead_root;
+       struct btrfs_item *item;
+       struct btrfs_root_item *ri;
+       struct btrfs_key key;
+       struct btrfs_path *path;
+       int ret;
+       u32 nritems;
+       struct btrfs_leaf *leaf;
+       int slot;
+
+       key.objectid = 0;
+       key.flags = 0;
+       btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY);
+       key.offset = 0;
+       path = btrfs_alloc_path();
+       if (!path)
+               return -ENOMEM;
+       ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
+       if (ret < 0)
+               goto err;
+       while(1) {
+               leaf = btrfs_buffer_leaf(path->nodes[0]);
+               nritems = btrfs_header_nritems(&leaf->header);
+               slot = path->slots[0];
+               if (slot >= nritems) {
+                       ret = btrfs_next_leaf(root, path);
+                       if (ret)
+                               break;
+                       leaf = btrfs_buffer_leaf(path->nodes[0]);
+                       nritems = btrfs_header_nritems(&leaf->header);
+                       slot = path->slots[0];
+               }
+               item = leaf->items + slot;
+               btrfs_disk_key_to_cpu(&key, &item->key);
+               if (btrfs_key_type(&key) != BTRFS_ROOT_ITEM_KEY)
+                       goto next;
+               ri = btrfs_item_ptr(leaf, slot, struct btrfs_root_item);
+               if (btrfs_root_refs(ri) != 0)
+                       goto next;
+               dead_root = btrfs_read_fs_root_no_radix(root->fs_info, &key);
+               if (IS_ERR(root)) {
+                       ret = PTR_ERR(root);
+                       goto err;
+               }
+printk("found dead root %Lu %u %Lu\n", key.objectid, key.flags, key.offset);
+               ret = btrfs_add_dead_root(dead_root,
+                                         &root->fs_info->dead_roots);
+               if (ret)
+                       goto err;
+next:
+               slot++;
+               path->slots[0]++;
+       }
+       ret = 0;
+err:
+       btrfs_free_path(path);
+       return ret;
+}
+
 int btrfs_del_root(struct btrfs_trans_handle *trans, struct btrfs_root *root,
                   struct btrfs_key *key)
 {
@@ -111,14 +174,8 @@ int btrfs_del_root(struct btrfs_trans_handle *trans, struct btrfs_root *root,
                            path->slots[0], struct btrfs_root_item);
 
        refs = btrfs_root_refs(ri);
-       BUG_ON(refs == 0);
-       if (refs == 1) {
-               ret = btrfs_del_item(trans, root, path);
-       } else {
-               btrfs_set_root_refs(ri, refs - 1);
-               WARN_ON(1);
-               mark_buffer_dirty(path->nodes[0]);
-       }
+       BUG_ON(refs != 0);
+       ret = btrfs_del_item(trans, root, path);
 out:
        btrfs_release_path(root, path);
        btrfs_free_path(path);