[PATCH] ceph: make sure all the files successfully put before unmounting

From: xiubli@redhat.com
To: idryomov@gmail.com, ceph-devel@vger.kernel.org
Cc: jlayton@kernel.org, khiremat@redhat.com,
	linux-fscrypt@vger.kernel.org, Xiubo Li <xiubli@redhat.com>
Subject: [PATCH] ceph: make sure all the files successfully put before unmounting
Date: Thu,  1 Dec 2022 14:58:00 +0800	[thread overview]
Message-ID: <20221201065800.18149-1-xiubli@redhat.com> (raw)

From: Xiubo Li <xiubli@redhat.com>

When close a file it will be deferred to call the fput(), which
will hold the inode's i_count. And when unmounting the mountpoint
the evict_inodes() may skip evicting some inodes.

If encrypt is enabled the kernel generate a warning when removing
the encrypt keys when the skipped inodes still hold the keyring:

WARNING: CPU: 4 PID: 168846 at fs/crypto/keyring.c:242 fscrypt_destroy_keyring+0x7e/0xd0
CPU: 4 PID: 168846 Comm: umount Tainted: G S  6.1.0-rc5-ceph-g72ead199864c #1
Hardware name: Supermicro SYS-5018R-WR/X10SRW-F, BIOS 2.0 12/17/2015
RIP: 0010:fscrypt_destroy_keyring+0x7e/0xd0
RSP: 0018:ffffc9000b277e28 EFLAGS: 00010202
RAX: 0000000000000002 RBX: ffff88810d52ac00 RCX: ffff88810b56aa00
RDX: 0000000080000000 RSI: ffffffff822f3a09 RDI: ffff888108f59000
RBP: ffff8881d394fb88 R08: 0000000000000028 R09: 0000000000000000
R10: 0000000000000001 R11: 11ff4fe6834fcd91 R12: ffff8881d394fc40
R13: ffff888108f59000 R14: ffff8881d394f800 R15: 0000000000000000
FS:  00007fd83f6f1080(0000) GS:ffff88885fd00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f918d417000 CR3: 000000017f89a005 CR4: 00000000003706e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
generic_shutdown_super+0x47/0x120
kill_anon_super+0x14/0x30
ceph_kill_sb+0x36/0x90 [ceph]
deactivate_locked_super+0x29/0x60
cleanup_mnt+0xb8/0x140
task_work_run+0x67/0xb0
exit_to_user_mode_prepare+0x23d/0x240
syscall_exit_to_user_mode+0x25/0x60
do_syscall_64+0x40/0x80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7fd83dc39e9b

URL: https://tracker.ceph.com/issues/58126
Signed-off-by: Xiubo Li <xiubli@redhat.com>
---
 fs/ceph/super.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/fs/ceph/super.c b/fs/ceph/super.c
index 3db6f95768a3..1f46db92e81f 100644
--- a/fs/ceph/super.c
+++ b/fs/ceph/super.c
@@ -9,6 +9,7 @@
 #include <linux/in6.h>
 #include <linux/module.h>
 #include <linux/mount.h>
+#include <linux/file.h>
 #include <linux/fs_context.h>
 #include <linux/fs_parser.h>
 #include <linux/sched.h>
@@ -1477,6 +1478,14 @@ static void ceph_kill_sb(struct super_block *s)
 	ceph_mdsc_pre_umount(fsc->mdsc);
 	flush_fs_workqueues(fsc);
 
+	/*
+	 * If the encrypt is enabled we need to make sure the delayed
+	 * fput to finish, which will make sure all the inodes will
+	 * be evicted before removing the encrypt keys.
+	 */
+	if (s->s_master_keys)
+		flush_delayed_fput();
+
 	kill_anon_super(s);
 
 	fsc->client->extra_mon_dispatch = NULL;
-- 
2.31.1

