[PATCH AUTOSEL 4.19 5/8] configfs_register_group() shouldn't be (and isn't) called in rmdirable parts

From: Sasha Levin
Date: Mon Sep 09 2019 - 18:17:00 EST


From: Al Viro <viro@xxxxxxxxxxxxxxxxxx>

[ Upstream commit f19e4ed1e1edbfa3c9ccb9fed17759b7d6db24c6 ]

revert cc57c07343bd "configfs: fix registered group removal"
It was an attempt to handle something that fundamentally doesn't
work - configfs_register_group() should never be done in a part
of tree that can be rmdir'ed. And in mainline it never had been,
so let's not borrow trouble; the fix was racy anyway, it would take
a lot more to make that work and desired semantics is not clear.

Signed-off-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
fs/configfs/dir.c | 11 -----------
1 file changed, 11 deletions(-)

diff --git a/fs/configfs/dir.c b/fs/configfs/dir.c
index 809c1edffbaf1..19c8ce2a40430 100644
--- a/fs/configfs/dir.c
+++ b/fs/configfs/dir.c
@@ -1782,16 +1782,6 @@ void configfs_unregister_group(struct config_group *group)
struct dentry *dentry = group->cg_item.ci_dentry;
struct dentry *parent = group->cg_item.ci_parent->ci_dentry;

- mutex_lock(&subsys->su_mutex);
- if (!group->cg_item.ci_parent->ci_group) {
- /*
- * The parent has already been unlinked and detached
- * due to a rmdir.
- */
- goto unlink_group;
- }
- mutex_unlock(&subsys->su_mutex);
-
inode_lock_nested(d_inode(parent), I_MUTEX_PARENT);
spin_lock(&configfs_dirent_lock);
configfs_detach_prep(dentry, NULL);
@@ -1806,7 +1796,6 @@ void configfs_unregister_group(struct config_group *group)
dput(dentry);

mutex_lock(&subsys->su_mutex);
-unlink_group:
unlink_group(group);
mutex_unlock(&subsys->su_mutex);
}
--
2.20.1