From 377e507d1572eca6372c862483f4ce4680ad310a Mon Sep 17 00:00:00 2001 From: Chuck Lever Date: Wed, 11 Jul 2012 16:29:45 -0400 Subject: [PATCH] NFS: Fix up TEST_STATEID and FREE_STATEID return code handling The TEST_STATEID and FREE_STATEID operations can return -NFS4ERR_BAD_STATEID, -NFS4ERR_OLD_STATEID, or -NFS4ERR_DEADSESSION. nfs41_{test,free}_stateid() should not pass these errors to nfs4_handle_exception() during state recovery, since that will recursively kick off state recovery again, resulting in a deadlock. In particular, when the TEST_STATEID operation returns NFS4_OK, res.status can contain one of these errors. _nfs41_test_stateid() replaces NFS4_OK with the value in res.status, which is then returned to callers. But res.status is not passed through nfs4_stat_to_errno(), and thus is a positive NFS4ERR value. Currently callers are only interested in !NFS4_OK, and nfs4_handle_exception() ignores positive values. Thus the res.status values are currently ignored by nfs4_handle_exception() and won't cause the deadlock above. Thanks to this missing negative, it is only when these operations fail (which is very rare) that a deadlock can occur. Bryan agrees the original intent was to return res.status as a negative NFS4ERR value to callers of nfs41_test_stateid(). Signed-off-by: Chuck Lever Signed-off-by: Trond Myklebust --- fs/nfs/nfs4proc.c | 24 +++++++++++++----------- 1 file changed, 13 insertions(+), 11 deletions(-) diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c index 006e98d..af3abf9 100644 --- a/fs/nfs/nfs4proc.c +++ b/fs/nfs/nfs4proc.c @@ -6578,10 +6578,9 @@ static int _nfs41_test_stateid(struct nfs_server *server, nfs4_stateid *stateid) nfs41_init_sequence(&args.seq_args, &res.seq_res, 0); status = nfs4_call_sync_sequence(server->client, server, &msg, &args.seq_args, &res.seq_res, 1); - - if (status == NFS_OK) - return res.status; - return status; + if (status != NFS_OK) + return status; + return -res.status; } static int nfs41_test_stateid(struct nfs_server *server, nfs4_stateid *stateid) @@ -6589,9 +6588,10 @@ static int nfs41_test_stateid(struct nfs_server *server, nfs4_stateid *stateid) struct nfs4_exception exception = { }; int err; do { - err = nfs4_handle_exception(server, - _nfs41_test_stateid(server, stateid), - &exception); + err = _nfs41_test_stateid(server, stateid); + if (err != -NFS4ERR_DELAY) + break; + nfs4_handle_exception(server, err, &exception); } while (exception.retry); return err; } @@ -6609,7 +6609,8 @@ static int _nfs4_free_stateid(struct nfs_server *server, nfs4_stateid *stateid) }; nfs41_init_sequence(&args.seq_args, &res.seq_res, 0); - return nfs4_call_sync_sequence(server->client, server, &msg, &args.seq_args, &res.seq_res, 1); + return nfs4_call_sync_sequence(server->client, server, &msg, + &args.seq_args, &res.seq_res, 1); } static int nfs41_free_stateid(struct nfs_server *server, nfs4_stateid *stateid) @@ -6617,9 +6618,10 @@ static int nfs41_free_stateid(struct nfs_server *server, nfs4_stateid *stateid) struct nfs4_exception exception = { }; int err; do { - err = nfs4_handle_exception(server, - _nfs4_free_stateid(server, stateid), - &exception); + err = _nfs4_free_stateid(server, stateid); + if (err != -NFS4ERR_DELAY) + break; + nfs4_handle_exception(server, err, &exception); } while (exception.retry); return err; } -- 2.7.4