linux-kernel - [PATCH] afs: Fix manually set volume location server list

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Message-ID: <155078667296.18898.13427509562134997807.stgit@warthog.procyon.org.uk>
Date:   Thu, 21 Feb 2019 22:04:32 +0000
From:   David Howells <dhowells@...hat.com>
To:     torvalds@...ux-foundation.org
Cc:     Dave Botsch <dwb7@...nell.edu>, dhowells@...hat.com,
        linux-afs@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: [PATCH] afs: Fix manually set volume location server list

When a cell with a volume location server list is added manually by echoing
the details into /proc/net/afs/cells, a record is added but the flag saying
it has been looked up isn't set.  This causes the VL server rotation code
to wait forever, with the top of /proc/pid/stack looking like:

	[<0>] afs_select_vlserver+0x3a6/0x6f3
	[<0>] afs_vl_lookup_vldb+0x4b/0x92
	[<0>] afs_create_volume+0x25/0x1b9
	...

with the thread stuck in afs_start_vl_iteration() waiting for
AFS_CELL_FL_NO_LOOKUP_YET to be cleared.

Fix this by clearing AFS_CELL_FL_NO_LOOKUP_YET when setting up a record if
that record's details were supplied manually.

Fixes: 0a5143f2f89c ("afs: Implement VL server rotation")
Reported-by: Dave Botsch <dwb7@...nell.edu>
Signed-off-by: David Howells <dhowells@...hat.com>
---

 fs/afs/cell.c |    1 +
 1 file changed, 1 insertion(+)

diff --git a/fs/afs/cell.c b/fs/afs/cell.c
index cf445dbd5f2e..9de46116c749 100644
--- a/fs/afs/cell.c
+++ b/fs/afs/cell.c
@@ -173,6 +173,7 @@ static struct afs_cell *afs_alloc_cell(struct afs_net *net,

 		rcu_assign_pointer(cell->vl_servers, vllist);
 		cell->dns_expiry = TIME64_MAX;
+		__clear_bit(AFS_CELL_FL_NO_LOOKUP_YET, &cell->flags);
 	} else {
 		cell->dns_expiry = ktime_get_real_seconds();
 	}