Btrfs: fix a bug of writting free space cache during balance

[linux-imx.git] / fs / btrfs / extent-tree.c

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 67bd12a5236927cc001157c978cee19d3f2cc304..3ca26d84cce563c1bc4430eed37e26f9ee86d258 100644 (file)
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -2903,8 +2903,13 @@ again:
        }
 
        spin_lock(&block_group->lock);
-       if (block_group->cached != BTRFS_CACHE_FINISHED) {
-               /* We're not cached, don't bother trying to write stuff out */
+       if (block_group->cached != BTRFS_CACHE_FINISHED ||
+           !btrfs_test_opt(root, SPACE_CACHE)) {
+               /*
+                * don't bother trying to write stuff out _if_
+                * a) we're not cached,
+                * b) we're with nospace_cache mount option.
+                */
                dcs = BTRFS_DC_WRITTEN;
                spin_unlock(&block_group->lock);
                goto out_put;
@@ -7614,8 +7619,21 @@ int btrfs_read_block_groups(struct btrfs_root *root)
                INIT_LIST_HEAD(&cache->list);
                INIT_LIST_HEAD(&cache->cluster_list);
 
-               if (need_clear)
+               if (need_clear) {
+                       /*
+                        * When we mount with old space cache, we need to
+                        * set BTRFS_DC_CLEAR and set dirty flag.
+                        *
+                        * a) Setting 'BTRFS_DC_CLEAR' makes sure that we
+                        *    truncate the old free space cache inode and
+                        *    setup a new one.
+                        * b) Setting 'dirty flag' makes sure that we flush
+                        *    the new space cache info onto disk.
+                        */
                        cache->disk_cache_state = BTRFS_DC_CLEAR;
+                       if (btrfs_test_opt(root, SPACE_CACHE))
+                               cache->dirty = 1;
+               }
 
                read_extent_buffer(leaf, &cache->item,
                                   btrfs_item_ptr_offset(leaf, path->slots[0]),