Re: [PATCH v10 4/5] NFSD: Implement NFSD_IO_DIRECT for NFS WRITE

[kernel test robot <lkp@intel.com>]

Hi Chuck,

kernel test robot noticed the following build errors:

[auto build test ERROR on linus/master]
[also build test ERROR on v6.18-rc5 next-20251110]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Chuck-Lever/NFSD-don-t-start-nfsd-if-sv_permsocks-is-empty/20251106-033348
base:   linus/master
patch link:    https://lore.kernel.org/r/20251105192806.77093-5-cel%40kernel.org
patch subject: [PATCH v10 4/5] NFSD: Implement NFSD_IO_DIRECT for NFS WRITE
config: mips-allyesconfig (https://download.01.org/0day-ci/archive/20251110/202511102150.Q7D6LAB6-lkp@intel.com/config)
compiler: mips-linux-gcc (GCC) 15.1.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20251110/202511102150.Q7D6LAB6-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202511102150.Q7D6LAB6-lkp@intel.com/

All errors (new ones prefixed by >>):

   fs/nfsd/vfs.c: In function 'nfsd_vfs_write':
>> fs/nfsd/vfs.c:1407:14: error: 'NFSD_IO_DIRECT' undeclared (first use in this function)
    1407 |         case NFSD_IO_DIRECT:
         |              ^~~~~~~~~~~~~~
   fs/nfsd/vfs.c:1407:14: note: each undeclared identifier is reported only once for each function it appears in
--
   fs/nfsd/debugfs.c: In function 'nfsd_io_cache_write_set':
>> fs/nfsd/debugfs.c:109:14: error: 'NFSD_IO_DIRECT' undeclared (first use in this function)
     109 |         case NFSD_IO_DIRECT:
         |              ^~~~~~~~~~~~~~
   fs/nfsd/debugfs.c:109:14: note: each undeclared identifier is reported only once for each function it appears in


vim +/NFSD_IO_DIRECT +1407 fs/nfsd/vfs.c

  1325	
  1326	/**
  1327	 * nfsd_vfs_write - write data to an already-open file
  1328	 * @rqstp: RPC execution context
  1329	 * @fhp: File handle of file to write into
  1330	 * @nf: An open file matching @fhp
  1331	 * @offset: Byte offset of start
  1332	 * @payload: xdr_buf containing the write payload
  1333	 * @cnt: IN: number of bytes to write, OUT: number of bytes actually written
  1334	 * @stable_how: IN: Client's requested stable_how, OUT: Actual stable_how
  1335	 * @verf: NFS WRITE verifier
  1336	 *
  1337	 * Upon return, caller must invoke fh_put on @fhp.
  1338	 *
  1339	 * Return values:
  1340	 *   An nfsstat value in network byte order.
  1341	 */
  1342	__be32
  1343	nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp,
  1344		       struct nfsd_file *nf, loff_t offset,
  1345		       const struct xdr_buf *payload, unsigned long *cnt,
  1346		       u32 *stable_how, __be32 *verf)
  1347	{
  1348		struct nfsd_net		*nn = net_generic(SVC_NET(rqstp), nfsd_net_id);
  1349		struct file		*file = nf->nf_file;
  1350		struct super_block	*sb = file_inode(file)->i_sb;
  1351		u32			stable = *stable_how;
  1352		struct kiocb		kiocb;
  1353		struct svc_export	*exp;
  1354		struct iov_iter		iter;
  1355		errseq_t		since;
  1356		__be32			nfserr;
  1357		int			host_err;
  1358		unsigned long		exp_op_flags = 0;
  1359		unsigned int		pflags = current->flags;
  1360		bool			restore_flags = false;
  1361		unsigned int		nvecs;
  1362	
  1363		trace_nfsd_write_opened(rqstp, fhp, offset, *cnt);
  1364	
  1365		if (sb->s_export_op)
  1366			exp_op_flags = sb->s_export_op->flags;
  1367	
  1368		if (test_bit(RQ_LOCAL, &rqstp->rq_flags) &&
  1369		    !(exp_op_flags & EXPORT_OP_REMOTE_FS)) {
  1370			/*
  1371			 * We want throttling in balance_dirty_pages()
  1372			 * and shrink_inactive_list() to only consider
  1373			 * the backingdev we are writing to, so that nfs to
  1374			 * localhost doesn't cause nfsd to lock up due to all
  1375			 * the client's dirty pages or its congested queue.
  1376			 */
  1377			current->flags |= PF_LOCAL_THROTTLE;
  1378			restore_flags = true;
  1379		}
  1380	
  1381		exp = fhp->fh_export;
  1382	
  1383		if (!EX_ISSYNC(exp))
  1384			stable = NFS_UNSTABLE;
  1385		init_sync_kiocb(&kiocb, file);
  1386		kiocb.ki_pos = offset;
  1387		if (likely(!fhp->fh_use_wgather)) {
  1388			switch (stable) {
  1389			case NFS_FILE_SYNC:
  1390				/* persist data and timestamps */
  1391				kiocb.ki_flags |= IOCB_DSYNC | IOCB_SYNC;
  1392				break;
  1393			case NFS_DATA_SYNC:
  1394				/* persist data only */
  1395				kiocb.ki_flags |= IOCB_DSYNC;
  1396				break;
  1397			}
  1398		}
  1399	
  1400		nvecs = xdr_buf_to_bvec(rqstp->rq_bvec, rqstp->rq_maxpages, payload);
  1401	
  1402		since = READ_ONCE(file->f_wb_err);
  1403		if (verf)
  1404			nfsd_copy_write_verifier(verf, nn);
  1405	
  1406		switch (nfsd_io_cache_write) {
> 1407		case NFSD_IO_DIRECT:
  1408			host_err = nfsd_direct_write(rqstp, fhp, nf, nvecs,
  1409						     cnt, &kiocb);
  1410			break;
  1411		case NFSD_IO_DONTCACHE:
  1412			if (file->f_op->fop_flags & FOP_DONTCACHE)
  1413				kiocb.ki_flags |= IOCB_DONTCACHE;
  1414			fallthrough;
  1415		case NFSD_IO_BUFFERED:
  1416			iov_iter_bvec(&iter, ITER_SOURCE, rqstp->rq_bvec, nvecs, *cnt);
  1417			host_err = vfs_iocb_iter_write(file, &kiocb, &iter);
  1418			if (host_err < 0)
  1419				break;
  1420			*cnt = host_err;
  1421			break;
  1422		}
  1423		if (host_err < 0) {
  1424			commit_reset_write_verifier(nn, rqstp, host_err);
  1425			goto out_nfserr;
  1426		}
  1427		nfsd_stats_io_write_add(nn, exp, *cnt);
  1428		fsnotify_modify(file);
  1429		host_err = filemap_check_wb_err(file->f_mapping, since);
  1430		if (host_err < 0)
  1431			goto out_nfserr;
  1432	
  1433		if (stable && fhp->fh_use_wgather) {
  1434			host_err = wait_for_concurrent_writes(file);
  1435			if (host_err < 0)
  1436				commit_reset_write_verifier(nn, rqstp, host_err);
  1437		}
  1438	
  1439	out_nfserr:
  1440		if (host_err >= 0) {
  1441			trace_nfsd_write_io_done(rqstp, fhp, offset, *cnt);
  1442			nfserr = nfs_ok;
  1443		} else {
  1444			trace_nfsd_write_err(rqstp, fhp, offset, host_err);
  1445			nfserr = nfserrno(host_err);
  1446		}
  1447		if (restore_flags)
  1448			current_restore_flags(pflags, PF_LOCAL_THROTTLE);
  1449		return nfserr;
  1450	}
  1451	

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