Josef Bacik wrote on 2016/04/26 10:24 -0400:
The new qgroup stuff needs the quota accounting to be run before doing the
inherit, unfortunately they need the commit root switch to happen at a specific
time for this to work properly. Fix this by delaying the inherit until after we
do the qgroup accounting, and remove the inherit and accounting dance in
create_pending_snapshot. Thanks,
Signed-off-by: Josef Bacik <jbacik@xxxxxx>
---
fs/btrfs/transaction.c | 51 ++++++++++++++++++++++++++++++--------------------
fs/btrfs/transaction.h | 1 +
2 files changed, 32 insertions(+), 20 deletions(-)
diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index 7c7671d..aa3025a 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -1353,6 +1353,7 @@ static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans,
pending->error = btrfs_find_free_objectid(tree_root, &objectid);
if (pending->error)
goto no_free_objectid;
+ pending->objectid = objectid;
/*
* Make qgroup to skip current new snapshot's qgroupid, as it is
@@ -1559,24 +1560,6 @@ static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans,
btrfs_abort_transaction(trans, root, ret);
goto fail;
}
-
- /*
- * account qgroup counters before qgroup_inherit()
- */
- ret = btrfs_qgroup_prepare_account_extents(trans, fs_info);
- if (ret)
- goto fail;
- ret = btrfs_qgroup_account_extents(trans, fs_info);
- if (ret)
- goto fail;
- ret = btrfs_qgroup_inherit(trans, fs_info,
- root->root_key.objectid,
- objectid, pending->inherit);
- if (ret) {
- btrfs_abort_transaction(trans, root, ret);
- goto fail;
- }
-
fail:
pending->error = ret;
dir_item_existed:
@@ -1599,15 +1582,35 @@ no_free_objectid:
static noinline int create_pending_snapshots(struct btrfs_trans_handle *trans,
struct btrfs_fs_info *fs_info)
{
+ struct btrfs_pending_snapshot *pending;
+ struct list_head *head = &trans->transaction->pending_snapshots;
+ int ret = 0;
+
+ list_for_each_entry(pending, head, list) {
+ ret = create_pending_snapshot(trans, fs_info, pending);
+ if (ret)
+ break;
+ }
+ return ret;
+}
+
+static noinline int inherit_pending_snapshots(struct btrfs_trans_handle *trans,
+ struct btrfs_fs_info *fs_info)
+{
struct btrfs_pending_snapshot *pending, *next;
struct list_head *head = &trans->transaction->pending_snapshots;
int ret = 0;
list_for_each_entry_safe(pending, next, head, list) {
+ struct btrfs_root *root = pending->root;
list_del(&pending->list);
- ret = create_pending_snapshot(trans, fs_info, pending);
- if (ret)
+ ret = btrfs_qgroup_inherit(trans, fs_info,
+ root->root_key.objectid,
+ pending->objectid, pending->inherit);
It's too late to call qgroup_inherit() here.
As we already inserted DIR_ITEM into parent_root.
This will cause qgroup difference, if parent_root is also the src_root.
But your fix provides a very potential fix method.
If we didn't do the DIR_ITEM insert in create_pending_snapshot, but do
the insert after all qgroup_inherit() is done,
the problem may have a better fix.
Although I am still concerning about the DIR_ITEM insert.
As we still need to account them, and since we must run qgroup
accounting before qgroup_inherit(), I'm afraid we still need to do the
commit hack though.
Thanks,
Qu
+ if (ret) {
+ btrfs_abort_transaction(trans, root, ret);
break;
+ }
}
return ret;
}
@@ -2084,6 +2087,14 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
goto scrub_continue;
}
+ /* Inherit the qgroup information for the snapshots. */
+ ret = inherit_pending_snapshots(trans, root->fs_info);
+ if (ret) {
+ mutex_unlock(&root->fs_info->reloc_mutex);
+ goto scrub_continue;
+ }
+
+
ret = commit_cowonly_roots(trans, root);
if (ret) {
mutex_unlock(&root->fs_info->tree_log_mutex);
diff --git a/fs/btrfs/transaction.h b/fs/btrfs/transaction.h
index 72be51f..c118e6e 100644
--- a/fs/btrfs/transaction.h
+++ b/fs/btrfs/transaction.h
@@ -144,6 +144,7 @@ struct btrfs_pending_snapshot {
/* block reservation for the operation */
struct btrfs_block_rsv block_rsv;
u64 qgroup_reserved;
+ u64 objectid;
/* extra metadata reseration for relocation */
int error;
bool readonly;
--
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