[PATCH 4.1 066/159] NFSv4.1: Fix a protocol issue with CLOSE stateids

Greg Kroah-Hartman
2015-09-26T21:41:57Z

From: Trond Myklebust <trond.myklebust@primarydata.com>

commit 4a1e2feb9d246775dee0f78ed5b18826bae2b1c5 upstream.

According to RFC5661 Section 18.2.4, CLOSE is supposed to return
the zero stateid. This means that nfs_clear_open_stateid_locked()
cannot assume that the result stateid will always match the 'other'
field of the existing open stateid when trying to determine a race
with a parallel OPEN.

Instead, we look at the argument, and check for matches.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
fs/nfs/nfs4proc.c | 15 ++++++++++-----
1 file changed, 10 insertions(+), 5 deletions(-)

--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -1216,6 +1216,7 @@ static void nfs_resync_open_stateid_lock
}

static void nfs_clear_open_stateid_locked(struct nfs4_state *state,
+ nfs4_stateid *arg_stateid,
nfs4_stateid *stateid, fmode_t fmode)
{
clear_bit(NFS_O_RDWR_STATE, &state->flags);
@@ -1234,8 +1235,9 @@ static void nfs_clear_open_stateid_locke
if (stateid == NULL)
return;
/* Handle races with OPEN */
- if (!nfs4_stateid_match_other(stateid, &state->open_stateid) ||
- !nfs4_stateid_is_newer(stateid, &state->open_stateid)) {
+ if (!nfs4_stateid_match_other(arg_stateid, &state->open_stateid) ||
+ (nfs4_stateid_match_other(stateid, &state->open_stateid) &&
+ !nfs4_stateid_is_newer(stateid, &state->open_stateid))) {
nfs_resync_open_stateid_locked(state);
return;
}
@@ -1244,10 +1246,12 @@ static void nfs_clear_open_stateid_locke
nfs4_stateid_copy(&state->open_stateid, stateid);
}

-static void nfs_clear_open_stateid(struct nfs4_state *state, nfs4_stateid *stateid, fmode_t fmode)
+static void nfs_clear_open_stateid(struct nfs4_state *state,
+ nfs4_stateid *arg_stateid,
+ nfs4_stateid *stateid, fmode_t fmode)
{
write_seqlock(&state->seqlock);
- nfs_clear_open_stateid_locked(state, stateid, fmode);
+ nfs_clear_open_stateid_locked(state, arg_stateid, stateid, fmode);
write_sequnlock(&state->seqlock);
if (test_bit(NFS_STATE_RECLAIM_NOGRACE, &state->flags))
nfs4_schedule_state_manager(state->owner->so_server->nfs_client);
@@ -2672,7 +2676,8 @@ static void nfs4_close_done(struct rpc_t
goto out_release;
}
}
- nfs_clear_open_stateid(state, res_stateid, calldata->arg.fmode);
+ nfs_clear_open_stateid(state, &calldata->arg.stateid,
+ res_stateid, calldata->arg.fmode);
out_release:
nfs_release_seqid(calldata->arg.seqid);
nfs_refresh_inode(calldata->inode, calldata->res.fattr);