北京龙芯＆debian用户俱乐部

1. https://patchwork.kernel.org/patch/2070961/

2. http://choon.net/forum/read.php?21,791943

1:

 diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
 index d89da40..1e2abda 100644
 --- a/fs/btrfs/disk-io.c
 +++ b/fs/btrfs/disk-io.c
 @@ -2689,6 +2689,7 @@ fail_trans_kthread:
  fail_cleaner:
      kthread_stop(fs_info-cleaner_kthread);
 
 +fail_block_groups:
      /*
       * make sure we're done with the btree inode before we stop our
       * kthreads
 @@ -2696,7 +2697,6 @@ fail_cleaner:
      filemap_write_and_wait(fs_info-btree_inode-i_mapping);
      invalidate_inode_pages2(fs_info-btree_inode-i_mapping);
 
 -fail_block_groups:
      btrfs_free_block_groups(fs_info);
 
  fail_tree_roots:
 
 Just a guess; but I don't know what would have started writes already...

2:

diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 9d09a4f..35c3a2a 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -3909,6 +3909,13 @@ int extent_range_uptodate(struct extent_io_tree *tree,
while (start <= end) {
index = start >> PAGE_CACHE_SHIFT;
page = find_get_page(tree->mapping, index);
+ if (unlikely(!page)) {
+ if (printk_ratelimit())
+ printk(KERN_WARNING
+ "btrfs: NULL page in "
+ "extent_range_uptodate()\n";
+ return 1;
+ }
uptodate = PageUptodate(page);
page_cache_release(page);
if (!uptodate) {