From 0ff7b35631ac5359a0adfcb0507cc08cdf94e154 Mon Sep 17 00:00:00 2001
From: Jeff Layton <jlayton@kernel.org>
Date: Thu, 30 Sep 2021 08:33:13 -0400
Subject: [PATCH] ceph: skip existing superblocks that are blocklisted or shut down when mounting
Git-commit: 98d0a6fb7303a6f4a120b8b8ed05b86ff5db53e8
Patch-mainline: v5.15-rc7
References: stable-5.14.15

commit 98d0a6fb7303a6f4a120b8b8ed05b86ff5db53e8 upstream.

Currently when mounting, we may end up finding an existing superblock
that corresponds to a blocklisted MDS client. This means that the new
mount ends up being unusable.

If we've found an existing superblock with a client that is already
blocklisted, and the client is not configured to recover on its own,
fail the match. Ditto if the superblock has been forcibly unmounted.

While we're in here, also rename "other" to the more conventional "fsc".

Cc: stable@vger.kernel.org
Url: https://bugzilla.redhat.com/show_bug.cgi?id=1901499
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Xiubo Li <xiubli@redhat.com>
Reviewed-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 fs/ceph/super.c | 17 ++++++++++++++---
 1 file changed, 14 insertions(+), 3 deletions(-)

diff --git a/fs/ceph/super.c b/fs/ceph/super.c
index 9b1b7f4cfdd4..fd8742bae847 100644
--- a/fs/ceph/super.c
+++ b/fs/ceph/super.c
@@ -1002,16 +1002,16 @@ static int ceph_compare_super(struct super_block *sb, struct fs_context *fc)
 	struct ceph_fs_client *new = fc->s_fs_info;
 	struct ceph_mount_options *fsopt = new->mount_options;
 	struct ceph_options *opt = new->client->options;
-	struct ceph_fs_client *other = ceph_sb_to_client(sb);
+	struct ceph_fs_client *fsc = ceph_sb_to_client(sb);
 
 	dout("ceph_compare_super %p\n", sb);
 
-	if (compare_mount_options(fsopt, opt, other)) {
+	if (compare_mount_options(fsopt, opt, fsc)) {
 		dout("monitor(s)/mount options don't match\n");
 		return 0;
 	}
 	if ((opt->flags & CEPH_OPT_FSID) &&
-	    ceph_fsid_compare(&opt->fsid, &other->client->fsid)) {
+	    ceph_fsid_compare(&opt->fsid, &fsc->client->fsid)) {
 		dout("fsid doesn't match\n");
 		return 0;
 	}
@@ -1019,6 +1019,17 @@ static int ceph_compare_super(struct super_block *sb, struct fs_context *fc)
 		dout("flags differ\n");
 		return 0;
 	}
+
+	if (fsc->blocklisted && !ceph_test_mount_opt(fsc, CLEANRECOVER)) {
+		dout("client is blocklisted (and CLEANRECOVER is not set)\n");
+		return 0;
+	}
+
+	if (fsc->mount_state == CEPH_MOUNT_SHUTDOWN) {
+		dout("client has been forcibly unmounted\n");
+		return 0;
+	}
+
 	return 1;
 }
 
-- 
2.26.2