Btrfs: resizer: don't hold the fs_mutex for long periods of time

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

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index c390fd847a27c9658d00d713ce7493afb1ded49a..c906bb19b2114b970d6938912a758c33fd292b14 100644 (file)
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -2331,6 +2331,7 @@ int btrfs_shrink_extent_tree(struct btrfs_root *root, u64 new_size)
        struct extent_buffer *leaf;
        u32 nritems;
        int ret;
+       int progress = 0;
 
        btrfs_set_super_total_bytes(&info->super_copy, new_size);
        block_group_cache = &info->block_group_cache;
@@ -2383,6 +2384,19 @@ next:
                }
 
                btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
+
+               if (progress && need_resched()) {
+                       memcpy(&key, &found_key, sizeof(key));
+                       mutex_unlock(&root->fs_info->fs_mutex);
+                       cond_resched();
+                       mutex_lock(&root->fs_info->fs_mutex);
+                       btrfs_release_path(root, path);
+                       btrfs_search_slot(NULL, root, &key, path, 0, 0);
+                       progress = 0;
+                       goto next;
+               }
+               progress = 1;
+
                if (btrfs_key_type(&found_key) != BTRFS_EXTENT_ITEM_KEY ||
                    found_key.objectid + found_key.offset <= cur_byte) {
                        path->slots[0]++;
@@ -2442,7 +2456,7 @@ bg_next:
                         */
                        memcpy(&key, &found_key, sizeof(key));
                        btrfs_release_path(root, path);
-                       continue;
+                       goto resched_check;
                }
 
                btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
@@ -2465,6 +2479,12 @@ bg_next:
                key.objectid = found_key.objectid + 1;
                btrfs_del_item(trans, root, path);
                btrfs_release_path(root, path);
+resched_check:
+               if (need_resched()) {
+                       mutex_unlock(&root->fs_info->fs_mutex);
+                       cond_resched();
+                       mutex_lock(&root->fs_info->fs_mutex);
+               }
        }
        clear_extent_dirty(&info->free_space_cache, new_size, (u64)-1,
                           GFP_NOFS);