Commit 4a1e2feb authored by Trond Myklebust's avatar Trond Myklebust
Browse files

NFSv4.1: Fix a protocol issue with CLOSE stateids 



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.

Cc: stable@vger.kernel.org # v4.0+
Signed-off-by: default avatarTrond Myklebust <trond.myklebust@primarydata.com>
parent 90816d1d

fs/nfs/nfs4proc.c

+10 −5
Original line number Diff line number Diff line
@@ -1231,6 +1231,7 @@ static void nfs_resync_open_stateid_locked(struct nfs4_state *state) 
}



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);
@@ -1249,8 +1250,9 @@ static void nfs_clear_open_stateid_locked(struct nfs4_state *state, 
	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;

	}
@@ -1259,10 +1261,12 @@ static void nfs_clear_open_stateid_locked(struct nfs4_state *state, 
	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);
@@ -2707,7 +2711,8 @@ static void nfs4_close_done(struct rpc_task *task, void *data) 
				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);

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