sysfs: don't remove existing directory on update failure

sysfs: don't remove existing directory on update failure

When sysfs_update_group() is called for a named group and create_files()
fails (e.g. -ENOMEM), internal_create_group() calls kernfs_remove(kn) on
the group directory.  In the update path, kn was obtained via
kernfs_find_and_get() and refers to a directory that already existed
before this call.  Removing it silently destroys a sysfs group that the
caller did not create.

Only remove the directory if we created it ourselves.  On update failure
the directory remains as it is left empty by remove_files() inside
create_files(), but can be repopulated by a retry.

Cc: Rajat Jain <rajatja@google.com>
Fixes: c855cf2759d2 ("sysfs: Fix internal_create_group() for named group updates")
Cc: stable <stable@kernel.org>
Assisted-by: gkh_clanker_t1000
Reviewed-by: Rafael J. Wysocki (Intel) <rafael@kernel.org>
Reviewed-by: Danilo Krummrich <dakr@kernel.org>
Link: https://patch.msgid.link/2026052003-uniquely-hastily-c093@gregkh
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>