diff options
| author | Josef Bacik <jbacik@fb.com> | 2014-03-28 17:16:01 -0400 |
|---|---|---|
| committer | Chris Mason <clm@fb.com> | 2014-04-07 09:08:39 -0700 |
| commit | 3f8a18cc53bd1be26eb5b5247e1386ad0e21b623 (patch) | |
| tree | 266eeb3baf38b968ae2186575ae70ef431cf159f /fs/btrfs/ctree.c | |
| parent | 9e351cc862b098d8ec8f8022d110932490794925 (diff) | |
| download | linux-0-day-3f8a18cc53bd1be26eb5b5247e1386ad0e21b623.tar.gz linux-0-day-3f8a18cc53bd1be26eb5b5247e1386ad0e21b623.tar.xz | |
Btrfs: hold the commit_root_sem when getting the commit root during send
We currently rely too heavily on roots being read-only to save us from just
accessing root->commit_root. We can easily balance blocks out from underneath a
read only root, so to save us from getting screwed make sure we only access
root->commit_root under the commit root sem. Thanks,
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
Diffstat (limited to 'fs/btrfs/ctree.c')
| -rw-r--r-- | fs/btrfs/ctree.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c index 9d89c1648e8ed..1bcfcdb23cf4c 100644 --- a/fs/btrfs/ctree.c +++ b/fs/btrfs/ctree.c @@ -2769,9 +2769,13 @@ again: * the commit roots are read only * so we always do read locks */ + if (p->need_commit_sem) + down_read(&root->fs_info->commit_root_sem); b = root->commit_root; extent_buffer_get(b); level = btrfs_header_level(b); + if (p->need_commit_sem) + up_read(&root->fs_info->commit_root_sem); if (!p->skip_locking) btrfs_tree_read_lock(b); } else { @@ -5436,6 +5440,7 @@ int btrfs_compare_trees(struct btrfs_root *left_root, * the right if possible or go up and right. */ + down_read(&left_root->fs_info->commit_root_sem); left_level = btrfs_header_level(left_root->commit_root); left_root_level = left_level; left_path->nodes[left_level] = left_root->commit_root; @@ -5445,6 +5450,7 @@ int btrfs_compare_trees(struct btrfs_root *left_root, right_root_level = right_level; right_path->nodes[right_level] = right_root->commit_root; extent_buffer_get(right_path->nodes[right_level]); + up_read(&left_root->fs_info->commit_root_sem); if (left_level == 0) btrfs_item_key_to_cpu(left_path->nodes[left_level], |