On 03/03/2015 11:35 AM, David Sterba wrote:
On Tue, Mar 03, 2015 at 07:02:58PM +0800, Liu Bo wrote:
On Mon, Mar 02, 2015 at 12:46:55PM -0500, Josef Bacik wrote:
Dave could hit this assert consistently running btrfs/078. This is because
when we update the block groups we could truncate the free space, which would
try to delete the csums for that range and dirty the csum root. For this to
happen we have to have already written out the csum root so it's kind of hard to
hit this case. This patch fixes this by changing the logic to only write the
dirty block groups if the dirty_cowonly_roots list is empty. This will get us
the same effect as before since we add the extent root last, and will cover the
case that we dirty some other root again but not the extent root. Thanks,
Free space inode is NODATASUM, so its searching csum tree in
__btrfs_free_extent() is really unnecessary, by skipping that, csum tree
won't be inserted into dirty_cowonly_roots list again, so it also passed btrfs/078,
at least on my box.
I can hit the bug [1] even with Josef's patch, I'm can test your fix if you
want.
MKFS_OPTIONS -- -O skinny-metadata,extref -m single -d single --mixed /dev/sdc1
MOUNT_OPTIONS -- -o enospc_debug,space_cache,noatime /dev/sdc1 /mnt/a2
on top of 3.19-rc5 with Chris' for-linus.
Can you try this on top of this patch and send me the logs? Thanks,
Josef
diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index 9936421..a54f9b5 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -219,6 +219,7 @@ static void add_root_to_dirty_list(struct btrfs_root *root)
spin_lock(&root->fs_info->trans_lock);
if (!test_and_set_bit(BTRFS_ROOT_DIRTY, &root->state)) {
+ printk(KERN_ERR "dirtying root %llu\n", root->objectid);
/* Want the extent tree to be the last on the list */
if (root->objectid == BTRFS_EXTENT_TREE_OBJECTID)
list_move_tail(&root->dirty_list,
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index b7f0502..2488a35 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -5369,6 +5369,8 @@ static int update_block_group(struct btrfs_trans_handle *trans,
spin_lock(&trans->transaction->dirty_bgs_lock);
if (list_empty(&cache->dirty_list)) {
+ printk(KERN_ERR "dirtying bg %llu\n",
+ cache->key.objectid);
list_add_tail(&cache->dirty_list,
&trans->transaction->dirty_bgs);
btrfs_get_block_group(cache);
diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index e1a96af..ec50d17 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -1027,6 +1027,10 @@ static int update_cowonly_root(struct btrfs_trans_handle *trans,
old_root_used = btrfs_root_used(&root->root_item);
+ printk(KERN_ERR "writing root %llu, dirty cowonly roots empty %d, "
+ "dirty bgs empty %d\n", root->objectid,
+ list_empty(&fs_info->dirty_cowonly_roots),
+ list_empty(&trans->transaction->dirty_bgs));
while (1) {
old_root_bytenr = btrfs_root_bytenr(&root->root_item);
@@ -1050,6 +1054,7 @@ static int update_cowonly_root(struct btrfs_trans_handle *trans,
old_root_used = btrfs_root_used(&root->root_item);
if (list_empty(&fs_info->dirty_cowonly_roots)) {
+ printk(KERN_ERR "writing dirty block groups\n");
ret = btrfs_write_dirty_block_groups(trans, root);
if (ret)
return ret;
@@ -1123,6 +1128,7 @@ static noinline int commit_cowonly_roots(struct btrfs_trans_handle *trans,
return ret;
}
+ printk(KERN_ERR "done writy dirty cowonly roots\n");
list_add_tail(&fs_info->extent_root->dirty_list,
&trans->transaction->switch_commits);
btrfs_after_dev_replace_commit(fs_info);
@@ -2000,6 +2006,14 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
switch_commit_roots(cur_trans, root->fs_info);
assert_qgroups_uptodate(trans);
+ if (!list_empty(&cur_trans->dirty_bgs)) {
+ struct btrfs_block_group_cache *cache;
+
+ cache = list_first_entry(&cur_trans->dirty_bgs,
+ struct btrfs_block_group_cache,
+ bg_list);
+ printk(KERN_ERR "bg %llu still dirty\n", cache->key.objectid);
+ }
ASSERT(list_empty(&cur_trans->dirty_bgs));
update_super_roots(root);
