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

Signed-off-by: Chris Mason <chris.mason@oracle.com>

1 files changed, 66 insertions, 9 deletions

diff --git a/fs/btrfs/root-tree.c b/fs/btrfs/root-tree.c
index ac0fae7780ff..737e5a38d17e 100644
--- 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);