This is a note to let you know that I've just added the patch titled
btrfs: qgroup: catch reserved space leaks at unmount time
to the 5.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
btrfs-qgroup-catch-reserved-space-leaks-at-unmount-t.patch
and it can be found in the queue-5.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit c093017f3b670ffa6b4f49d929f1973cc143cddb
Author: Qu Wenruo <wqu@xxxxxxxx>
Date: Wed Jun 10 09:04:44 2020 +0800
btrfs: qgroup: catch reserved space leaks at unmount time
[ Upstream commit 5958253cf65de42493f17f36877a901486a90365 ]
Before this patch, qgroup completely relies on per-inode extent io tree
to detect reserved data space leak.
However previous bug has already shown how release page before
btrfs_finish_ordered_io() could lead to leak, and since it's
QGROUP_RESERVED bit cleared without triggering qgroup rsv, it can't be
detected by per-inode extent io tree.
So this patch adds another (and hopefully the final) safety net to catch
qgroup data reserved space leak. At least the new safety net catches
all the leaks during development, so it should be pretty useful in the
real world.
Reviewed-by: Josef Bacik <josef@xxxxxxxxxxxxxx>
Signed-off-by: Qu Wenruo <wqu@xxxxxxxx>
Reviewed-by: David Sterba <dsterba@xxxxxxxx>
Signed-off-by: David Sterba <dsterba@xxxxxxxx>
Stable-dep-of: 8a4a0b2a3eaf ("btrfs: fix race between quota disable and relocation")
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 7e9d914369a02..d98cf8aba753b 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -4106,6 +4106,11 @@ void close_ctree(struct btrfs_fs_info *fs_info)
ASSERT(list_empty(&fs_info->delayed_iputs));
set_bit(BTRFS_FS_CLOSING_DONE, &fs_info->flags);
+ if (btrfs_check_quota_leak(fs_info)) {
+ WARN_ON(IS_ENABLED(CONFIG_BTRFS_DEBUG));
+ btrfs_err(fs_info, "qgroup reserved space leaked");
+ }
+
btrfs_free_qgroup_config(fs_info);
ASSERT(list_empty(&fs_info->delalloc_roots));
diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c
index db8f83ab55f63..7821bef061fe6 100644
--- a/fs/btrfs/qgroup.c
+++ b/fs/btrfs/qgroup.c
@@ -504,6 +504,49 @@ int btrfs_read_qgroup_config(struct btrfs_fs_info *fs_info)
return ret < 0 ? ret : 0;
}
+static u64 btrfs_qgroup_subvolid(u64 qgroupid)
+{
+ return (qgroupid & ((1ULL << BTRFS_QGROUP_LEVEL_SHIFT) - 1));
+}
+
+/*
+ * Called in close_ctree() when quota is still enabled. This verifies we don't
+ * leak some reserved space.
+ *
+ * Return false if no reserved space is left.
+ * Return true if some reserved space is leaked.
+ */
+bool btrfs_check_quota_leak(struct btrfs_fs_info *fs_info)
+{
+ struct rb_node *node;
+ bool ret = false;
+
+ if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags))
+ return ret;
+ /*
+ * Since we're unmounting, there is no race and no need to grab qgroup
+ * lock. And here we don't go post-order to provide a more user
+ * friendly sorted result.
+ */
+ for (node = rb_first(&fs_info->qgroup_tree); node; node = rb_next(node)) {
+ struct btrfs_qgroup *qgroup;
+ int i;
+
+ qgroup = rb_entry(node, struct btrfs_qgroup, node);
+ for (i = 0; i < BTRFS_QGROUP_RSV_LAST; i++) {
+ if (qgroup->rsv.values[i]) {
+ ret = true;
+ btrfs_warn(fs_info,
+ "qgroup %llu/%llu has unreleased space, type %d rsv %llu",
+ btrfs_qgroup_level(qgroup->qgroupid),
+ btrfs_qgroup_subvolid(qgroup->qgroupid),
+ i, qgroup->rsv.values[i]);
+ }
+ }
+ }
+ return ret;
+}
+
/*
* This is called from close_ctree() or open_ctree() or btrfs_quota_disable(),
* first two are in single-threaded paths.And for the third one, we have set
diff --git a/fs/btrfs/qgroup.h b/fs/btrfs/qgroup.h
index 0a2659685ad65..94bdfb89505e8 100644
--- a/fs/btrfs/qgroup.h
+++ b/fs/btrfs/qgroup.h
@@ -416,5 +416,6 @@ int btrfs_qgroup_add_swapped_blocks(struct btrfs_trans_handle *trans,
int btrfs_qgroup_trace_subtree_after_cow(struct btrfs_trans_handle *trans,
struct btrfs_root *root, struct extent_buffer *eb);
void btrfs_qgroup_destroy_extent_records(struct btrfs_transaction *trans);
+bool btrfs_check_quota_leak(struct btrfs_fs_info *fs_info);
#endif
