NFS/filelayout: Fix racy setting of fl->dsaddr in filelayout_check_deviceid()

[karo-tx-linux.git] / fs / nfs / filelayout / filelayout.c

diff --git a/fs/nfs/filelayout/filelayout.c b/fs/nfs/filelayout/filelayout.c
index 1cf85d65b7489bd56c69447d618360263febc52c..44c638b7876cfd5824d2d6287731e4411ea02052 100644 (file)
--- a/fs/nfs/filelayout/filelayout.c
+++ b/fs/nfs/filelayout/filelayout.c
@@ -126,32 +126,13 @@ static int filelayout_async_handle_error(struct rpc_task *task,
 {
        struct pnfs_layout_hdr *lo = lseg->pls_layout;
        struct inode *inode = lo->plh_inode;
-       struct nfs_server *mds_server = NFS_SERVER(inode);
        struct nfs4_deviceid_node *devid = FILELAYOUT_DEVID_NODE(lseg);
-       struct nfs_client *mds_client = mds_server->nfs_client;
        struct nfs4_slot_table *tbl = &clp->cl_session->fc_slot_table;
 
        if (task->tk_status >= 0)
                return 0;
 
        switch (task->tk_status) {
-       /* MDS state errors */
-       case -NFS4ERR_DELEG_REVOKED:
-       case -NFS4ERR_ADMIN_REVOKED:
-       case -NFS4ERR_BAD_STATEID:
-       case -NFS4ERR_OPENMODE:
-               if (state == NULL)
-                       break;
-               if (nfs4_schedule_stateid_recovery(mds_server, state) < 0)
-                       goto out_bad_stateid;
-               goto wait_on_recovery;
-       case -NFS4ERR_EXPIRED:
-               if (state != NULL) {
-                       if (nfs4_schedule_stateid_recovery(mds_server, state) < 0)
-                               goto out_bad_stateid;
-               }
-               nfs4_schedule_lease_recovery(mds_client);
-               goto wait_on_recovery;
        /* DS session errors */
        case -NFS4ERR_BADSESSION:
        case -NFS4ERR_BADSLOT:
@@ -172,6 +153,7 @@ static int filelayout_async_handle_error(struct rpc_task *task,
        case -NFS4ERR_RETRY_UNCACHED_REP:
                break;
        /* Invalidate Layout errors */
+       case -NFS4ERR_ACCESS:
        case -NFS4ERR_PNFS_NO_LAYOUT:
        case -ESTALE:           /* mapped NFS4ERR_STALE */
        case -EBADHANDLE:       /* mapped NFS4ERR_BADHANDLE */
@@ -202,26 +184,17 @@ static int filelayout_async_handle_error(struct rpc_task *task,
                        task->tk_status);
                nfs4_mark_deviceid_unavailable(devid);
                pnfs_error_mark_layout_for_return(inode, lseg);
+               pnfs_set_lo_fail(lseg);
                rpc_wake_up(&tbl->slot_tbl_waitq);
                /* fall through */
        default:
-               pnfs_set_lo_fail(lseg);
 reset:
                dprintk("%s Retry through MDS. Error %d\n", __func__,
                        task->tk_status);
                return -NFS4ERR_RESET_TO_MDS;
        }
-out:
        task->tk_status = 0;
        return -EAGAIN;
-out_bad_stateid:
-       task->tk_status = -EIO;
-       return 0;
-wait_on_recovery:
-       rpc_sleep_on(&mds_client->cl_rpcwaitq, task, NULL);
-       if (test_bit(NFS4CLNT_MANAGER_RUNNING, &mds_client->cl_state) == 0)
-               rpc_wake_up_queued_task(&mds_client->cl_rpcwaitq, task);
-       goto out;
 }
 
 /* NFS_PROTO call done callback routines */
@@ -569,6 +542,10 @@ filelayout_check_deviceid(struct pnfs_layout_hdr *lo,
        struct nfs4_file_layout_dsaddr *dsaddr;
        int status = -EINVAL;
 
+       /* Is the deviceid already set? If so, we're good. */
+       if (fl->dsaddr != NULL)
+               return 0;
+
        /* find and reference the deviceid */
        d = nfs4_find_get_deviceid(NFS_SERVER(lo->plh_inode), &fl->deviceid,
                        lo->plh_lc_cred, gfp_flags);
@@ -580,8 +557,6 @@ filelayout_check_deviceid(struct pnfs_layout_hdr *lo,
        if (filelayout_test_devid_unavailable(&dsaddr->id_node))
                goto out_put;
 
-       fl->dsaddr = dsaddr;
-
        if (fl->first_stripe_index >= dsaddr->stripe_count) {
                dprintk("%s Bad first_stripe_index %u\n",
                                __func__, fl->first_stripe_index);
@@ -597,6 +572,13 @@ filelayout_check_deviceid(struct pnfs_layout_hdr *lo,
                goto out_put;
        }
        status = 0;
+
+       /*
+        * Atomic compare and xchange to ensure we don't scribble
+        * over a non-NULL pointer.
+        */
+       if (cmpxchg(&fl->dsaddr, NULL, dsaddr) != NULL)
+               goto out_put;
 out:
        return status;
 out_put: