Merge branch 'for-chris-4.5' of git://git.kernel.org/pub/scm/linux/kernel/git/fdmanan...

[karo-tx-linux.git] / fs / btrfs / volumes.c

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 54d2d2cc2c928077ad649fac00ce8bccb0a36231..a37cc0478bb21534d930f44feb926fd89f2a67cc 100644 (file)
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -4825,20 +4825,32 @@ int btrfs_finish_chunk_alloc(struct btrfs_trans_handle *trans,
                goto out;
        }
 
+       /*
+        * Take the device list mutex to prevent races with the final phase of
+        * a device replace operation that replaces the device object associated
+        * with the map's stripes, because the device object's id can change
+        * at any time during that final phase of the device replace operation
+        * (dev-replace.c:btrfs_dev_replace_finishing()).
+        */
+       mutex_lock(&chunk_root->fs_info->fs_devices->device_list_mutex);
        for (i = 0; i < map->num_stripes; i++) {
                device = map->stripes[i].dev;
                dev_offset = map->stripes[i].physical;
 
                ret = btrfs_update_device(trans, device);
                if (ret)
-                       goto out;
+                       break;
                ret = btrfs_alloc_dev_extent(trans, device,
                                             chunk_root->root_key.objectid,
                                             BTRFS_FIRST_CHUNK_TREE_OBJECTID,
                                             chunk_offset, dev_offset,
                                             stripe_size);
                if (ret)
-                       goto out;
+                       break;
+       }
+       if (ret) {
+               mutex_unlock(&chunk_root->fs_info->fs_devices->device_list_mutex);
+               goto out;
        }
 
        stripe = &chunk->stripe;
@@ -4851,6 +4863,7 @@ int btrfs_finish_chunk_alloc(struct btrfs_trans_handle *trans,
                memcpy(stripe->dev_uuid, device->uuid, BTRFS_UUID_SIZE);
                stripe++;
        }
+       mutex_unlock(&chunk_root->fs_info->fs_devices->device_list_mutex);
 
        btrfs_set_stack_chunk_length(chunk, chunk_size);
        btrfs_set_stack_chunk_owner(chunk, extent_root->root_key.objectid);