From: Trond Myklebust <trond.myklebust@hammerspace.com>
Date: Mon, 5 Nov 2018 16:10:50 +0000 (-0500)
Subject: NFSv4: Don't exit the state manager without clearing NFS4CLNT_MANAGER_RUNNING
X-Git-Tag: v5.15~7579^2~4
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=21a446cf186570168b7281b154b1993968598aca;p=platform%2Fkernel%2Flinux-starfive.git

NFSv4: Don't exit the state manager without clearing NFS4CLNT_MANAGER_RUNNING

If we exit the NFSv4 state manager due to a umount, then we can end up
leaving the NFS4CLNT_MANAGER_RUNNING flag set. If another mount causes
the nfs4_client to be rereferenced before it is destroyed, then we end
up never being able to recover state.

Fixes: 47c2199b6eb5 ("NFSv4.1: Ensure state manager thread dies on last ...")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: stable@vger.kernel.org # v4.15+
---

diff --git a/fs/nfs/nfs4state.c b/fs/nfs/nfs4state.c
index 62ae0fd..98d1b6a 100644
--- a/fs/nfs/nfs4state.c
+++ b/fs/nfs/nfs4state.c
@@ -2601,11 +2601,12 @@ static void nfs4_state_manager(struct nfs_client *clp)
 		nfs4_clear_state_manager_bit(clp);
 		/* Did we race with an attempt to give us more work? */
 		if (clp->cl_state == 0)
-			break;
+			return;
 		if (test_and_set_bit(NFS4CLNT_MANAGER_RUNNING, &clp->cl_state) != 0)
-			break;
+			return;
 	} while (refcount_read(&clp->cl_count) > 1);
-	return;
+	goto out_drain;
+
 out_error:
 	if (strlen(section))
 		section_sep = ": ";
@@ -2613,6 +2614,7 @@ out_error:
 			" with error %d\n", section_sep, section,
 			clp->cl_hostname, -status);
 	ssleep(1);
+out_drain:
 	nfs4_end_drain_session(clp);
 	nfs4_clear_state_manager_bit(clp);
 }