1 files changed, 57 insertions, 18 deletions

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index d2358c06bbd9..be953afe804c 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -719,10 +719,9 @@ error:
  * called very infrequently and that a given device has a small number
  * of extents
  */
-static noinline int find_free_dev_extent(struct btrfs_trans_handle *trans,
-                                         struct btrfs_device *device,
-                                         u64 num_bytes, u64 *start,
-                                         u64 *max_avail)
+int find_free_dev_extent(struct btrfs_trans_handle *trans,
+                         struct btrfs_device *device, u64 num_bytes,
+                         u64 *start, u64 *max_avail)
 {
         struct btrfs_key key;
         struct btrfs_root *root = device->dev_root;
@@ -1736,6 +1735,10 @@ static int btrfs_relocate_chunk(struct btrfs_root *root,
         extent_root = root->fs_info->extent_root;
         em_tree = &root->fs_info->mapping_tree.map_tree;
 
+        ret = btrfs_can_relocate(extent_root, chunk_offset);
+        if (ret)
+                return -ENOSPC;
+
         /* step one, relocate all the extents inside this chunk */
         ret = btrfs_relocate_block_group(extent_root, chunk_offset);
         BUG_ON(ret);
@@ -1807,12 +1810,15 @@ static int btrfs_relocate_sys_chunks(struct btrfs_root *root)
         struct btrfs_key found_key;
         u64 chunk_tree = chunk_root->root_key.objectid;
         u64 chunk_type;
+        bool retried = false;
+        int failed = 0;
         int ret;
 
         path = btrfs_alloc_path();
         if (!path)
                 return -ENOMEM;
 
+again:
         key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
         key.offset = (u64)-1;
         key.type = BTRFS_CHUNK_ITEM_KEY;
@@ -1842,7 +1848,10 @@ static int btrfs_relocate_sys_chunks(struct btrfs_root *root)
                         ret = btrfs_relocate_chunk(chunk_root, chunk_tree,
                                                    found_key.objectid,
                                                    found_key.offset);
-                        BUG_ON(ret);
+                        if (ret == -ENOSPC)
+                                failed++;
+                        else if (ret)
+                                BUG();
                 }
 
                 if (found_key.offset == 0)
@@ -1850,6 +1859,14 @@ static int btrfs_relocate_sys_chunks(struct btrfs_root *root)
                 key.offset = found_key.offset - 1;
         }
         ret = 0;
+        if (failed && !retried) {
+                failed = 0;
+                retried = true;
+                goto again;
+        } else if (failed && retried) {
+                WARN_ON(1);
+                ret = -ENOSPC;
+        }
 error:
         btrfs_free_path(path);
         return ret;
@@ -1894,6 +1911,8 @@ int btrfs_balance(struct btrfs_root *dev_root)
                         continue;
 
                 ret = btrfs_shrink_device(device, old_size - size_to_free);
+                if (ret == -ENOSPC)
+                        break;
                 BUG_ON(ret);
 
                 trans = btrfs_start_transaction(dev_root, 1);
@@ -1938,9 +1957,8 @@ int btrfs_balance(struct btrfs_root *dev_root)
                 chunk = btrfs_item_ptr(path->nodes[0],
                                        path->slots[0],
                                        struct btrfs_chunk);
-                key.offset = found_key.offset;
                 /* chunk zero is special */
-                if (key.offset == 0)
+                if (found_key.offset == 0)
                         break;
 
                 btrfs_release_path(chunk_root, path);
@@ -1948,7 +1966,8 @@ int btrfs_balance(struct btrfs_root *dev_root)
                                            chunk_root->root_key.objectid,
                                            found_key.objectid,
                                            found_key.offset);
-                BUG_ON(ret);
+                BUG_ON(ret && ret != -ENOSPC);
+                key.offset = found_key.offset - 1;
         }
         ret = 0;
 error:
@@ -1974,10 +1993,13 @@ int btrfs_shrink_device(struct btrfs_device *device, u64 new_size)
         u64 chunk_offset;
         int ret;
         int slot;
+        int failed = 0;
+        bool retried = false;
         struct extent_buffer *l;
         struct btrfs_key key;
         struct btrfs_super_block *super_copy = &root->fs_info->super_copy;
         u64 old_total = btrfs_super_total_bytes(super_copy);
+        u64 old_size = device->total_bytes;
         u64 diff = device->total_bytes - new_size;
 
         if (new_size >= device->total_bytes)
@@ -1987,12 +2009,6 @@ int btrfs_shrink_device(struct btrfs_device *device, u64 new_size)
         if (!path)
                 return -ENOMEM;
 
-        trans = btrfs_start_transaction(root, 1);
-        if (!trans) {
-                ret = -ENOMEM;
-                goto done;
-        }
-
         path->reada = 2;
 
         lock_chunks(root);
@@ -2001,8 +2017,8 @@ int btrfs_shrink_device(struct btrfs_device *device, u64 new_size)
         if (device->writeable)
                 device->fs_devices->total_rw_bytes -= diff;
         unlock_chunks(root);
-        btrfs_end_transaction(trans, root);
 
+again:
         key.objectid = device->devid;
         key.offset = (u64)-1;
         key.type = BTRFS_DEV_EXTENT_KEY;
@@ -2017,6 +2033,7 @@ int btrfs_shrink_device(struct btrfs_device *device, u64 new_size)
                         goto done;
                 if (ret) {
                         ret = 0;
+                        btrfs_release_path(root, path);
                         break;
                 }
 
@@ -2024,14 +2041,18 @@ int btrfs_shrink_device(struct btrfs_device *device, u64 new_size)
                 slot = path->slots[0];
                 btrfs_item_key_to_cpu(l, &key, path->slots[0]);
 
-                if (key.objectid != device->devid)
+                if (key.objectid != device->devid) {
+                        btrfs_release_path(root, path);
                         break;
+                }
 
                 dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
                 length = btrfs_dev_extent_length(l, dev_extent);
 
-                if (key.offset + length <= new_size)
+                if (key.offset + length <= new_size) {
+                        btrfs_release_path(root, path);
                         break;
+                }
 
                 chunk_tree = btrfs_dev_extent_chunk_tree(l, dev_extent);
                 chunk_objectid = btrfs_dev_extent_chunk_objectid(l, dev_extent);
@@ -2040,8 +2061,26 @@ int btrfs_shrink_device(struct btrfs_device *device, u64 new_size)
 
                 ret = btrfs_relocate_chunk(root, chunk_tree, chunk_objectid,
                                            chunk_offset);
-                if (ret)
+                if (ret && ret != -ENOSPC)
                         goto done;
+                if (ret == -ENOSPC)
+                        failed++;
+                key.offset -= 1;
+        }
+
+        if (failed && !retried) {
+                failed = 0;
+                retried = true;
+                goto again;
+        } else if (failed && retried) {
+                ret = -ENOSPC;
+                lock_chunks(root);
+
+                device->total_bytes = old_size;
+                if (device->writeable)
+                        device->fs_devices->total_rw_bytes += diff;
+                unlock_chunks(root);
+                goto done;
         }
 
         /* Shrinking succeeded, else we would be at "done". */