Btrfs: add a device id to device items

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

1 files changed, 20 insertions, 11 deletions

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 3ba4df20c913..06b969c14625 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -13,11 +13,13 @@
 struct dev_lookup {
         u64 block_start;
         u64 num_blocks;
+        u64 device_id;
         struct block_device *bdev;
 };
 
 int btrfs_insert_dev_radix(struct btrfs_root *root,
                            struct block_device *bdev,
+                           u64 device_id,
                            u64 block_start,
                            u64 num_blocks)
 {
@@ -31,6 +33,7 @@ int btrfs_insert_dev_radix(struct btrfs_root *root,
         lookup->block_start = block_start;
         lookup->num_blocks = num_blocks;
         lookup->bdev = bdev;
+        lookup->device_id = device_id;
 printk("inserting %s into dev radix %Lu %Lu\n", bdevname(bdev, b), block_start, num_blocks);
 
         ret = radix_tree_insert(&root->fs_info->dev_radix, block_start +
@@ -418,17 +421,14 @@ printk("all worked\n");
         return root;
 }
 
-int btrfs_open_disk(struct btrfs_root *root, u64 block_start, u64 num_blocks,
-                    char *filename, int name_len)
+static int btrfs_open_disk(struct btrfs_root *root, u64 device_id,
+                           u64 block_start, u64 num_blocks,
+                           char *filename, int name_len)
 {
         char *null_filename;
         struct block_device *bdev;
         int ret;
 
-        if (block_start == 0) {
-printk("skipping disk with block_start == 0\n");
-return 0;
-        }
         null_filename = kmalloc(name_len + 1, GFP_NOFS);
         if (!null_filename)
                 return -ENOMEM;
@@ -441,7 +441,8 @@ return 0;
                 goto out;
         }
         set_blocksize(bdev, root->fs_info->sb->s_blocksize);
-        ret = btrfs_insert_dev_radix(root, bdev, block_start, num_blocks);
+        ret = btrfs_insert_dev_radix(root, bdev, device_id,
+                                     block_start, num_blocks);
         BUG_ON(ret);
         ret = 0;
 out:
@@ -490,10 +491,14 @@ static int read_device_info(struct btrfs_root *root)
                 }
                 dev_item = btrfs_item_ptr(leaf, slot, struct btrfs_device_item);
 printk("found key %Lu %Lu\n", key.objectid, key.offset);
-                ret = btrfs_open_disk(root, key.objectid, key.offset,
-                                      (char *)(dev_item + 1),
-                                      btrfs_device_pathlen(dev_item));
-                BUG_ON(ret);
+                if (btrfs_device_id(dev_item) !=
+                    btrfs_super_device_id(root->fs_info->disk_super)) {
+                        ret = btrfs_open_disk(root, btrfs_device_id(dev_item),
+                                              key.objectid, key.offset,
+                                              (char *)(dev_item + 1),
+                                              btrfs_device_pathlen(dev_item));
+                        BUG_ON(ret);
+                }
                 path->slots[0]++;
         }
         btrfs_free_path(path);
@@ -556,6 +561,7 @@ struct btrfs_root *open_ctree(struct super_block *sb)
         dev_lookup->block_start = 0;
         dev_lookup->num_blocks = (u32)-2;
         dev_lookup->bdev = sb->s_bdev;
+        dev_lookup->device_id = 0;
         ret = radix_tree_insert(&fs_info->dev_radix, (u32)-2, dev_lookup);
         BUG_ON(ret);
         fs_info->sb_buffer = read_tree_block(tree_root,
@@ -575,6 +581,8 @@ struct btrfs_root *open_ctree(struct super_block *sb)
         radix_tree_delete(&fs_info->dev_radix, (u32)-2);
         dev_lookup->block_start = btrfs_super_device_block_start(disk_super);
         dev_lookup->num_blocks = btrfs_super_device_num_blocks(disk_super);
+        dev_lookup->device_id = btrfs_super_device_id(disk_super);
+
         ret = radix_tree_insert(&fs_info->dev_radix,
                                 dev_lookup->block_start +
                                 dev_lookup->num_blocks - 1, dev_lookup);
@@ -659,6 +667,7 @@ int del_fs_roots(struct btrfs_fs_info *fs_info)
         }
         return 0;
 }
+
 static int free_dev_radix(struct btrfs_fs_info *fs_info)
 {
         struct dev_lookup *lookup[8];