From: Trond Myklebust <trond.myklebust@primarydata.com>
Date: Fri, 23 Jan 2015 23:06:09 +0000 (-0500)
Subject: NFSv4: More CLOSE/OPEN races
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=f95549cf24660255c880b3ea7ee2d7d08de1f5c5;p=linux-beck.git

NFSv4: More CLOSE/OPEN races

If an OPEN RPC call races with a CLOSE or OPEN_DOWNGRADE so that it
updates the nfs_state structure before the CLOSE/OPEN_DOWNGRADE has
a chance to do so, then we know that the state->flags need to be
recalculated from scratch.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
---

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 4863dec10865..a6c04a5812d0 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -1167,6 +1167,16 @@ static bool nfs_need_update_open_stateid(struct nfs4_state *state,
 	return false;
 }
 
+static void nfs_resync_open_stateid_locked(struct nfs4_state *state)
+{
+	if (state->n_wronly)
+		set_bit(NFS_O_WRONLY_STATE, &state->flags);
+	if (state->n_rdonly)
+		set_bit(NFS_O_RDONLY_STATE, &state->flags);
+	if (state->n_rdwr)
+		set_bit(NFS_O_RDWR_STATE, &state->flags);
+}
+
 static void nfs_clear_open_stateid_locked(struct nfs4_state *state,
 		nfs4_stateid *stateid, fmode_t fmode)
 {
@@ -1185,8 +1195,12 @@ static void nfs_clear_open_stateid_locked(struct nfs4_state *state,
 	}
 	if (stateid == NULL)
 		return;
-	if (!nfs_need_update_open_stateid(state, stateid))
+	/* Handle races with OPEN */
+	if (!nfs4_stateid_match_other(stateid, &state->open_stateid) ||
+	    !nfs4_stateid_is_newer(stateid, &state->open_stateid)) {
+		nfs_resync_open_stateid_locked(state);
 		return;
+	}
 	if (test_bit(NFS_DELEGATED_STATE, &state->flags) == 0)
 		nfs4_stateid_copy(&state->stateid, stateid);
 	nfs4_stateid_copy(&state->open_stateid, stateid);