Commit 474bc334 authored by Trond Myklebust's avatar Trond Myklebust Committed by J. Bruce Fields
Browse files

nfsd: Reduce contention for the nfsd_file nf_rwsem 



When flushing out the unstable file writes as part of a COMMIT call, try
to perform most of of the data writes and waits outside the semaphore.

This means that if the client is sending the COMMIT as part of a memory
reclaim operation, then it can continue performing I/O, with contention
for the lock occurring only once the data sync is finished.

Fixes: 5011af4c ("nfsd: Fix stable writes")
Signed-off-by: default avatarTrond Myklebust <trond.myklebust@hammerspace.com>
 Tested-by: default avatarChuck Lever <chuck.lever@oracle.com>
Signed-off-by: default avatarJ. Bruce Fields <bfields@redhat.com>
parent 0ff5b50a

fs/nfsd/vfs.c

+16 −2
Original line number Diff line number Diff line
@@ -1123,6 +1123,19 @@ nfsd_write(struct svc_rqst *rqstp, struct svc_fh *fhp, loff_t offset, 
}



#ifdef CONFIG_NFSD_V3

static int

nfsd_filemap_write_and_wait_range(struct nfsd_file *nf, loff_t offset,

				  loff_t end)

{

	struct address_space *mapping = nf->nf_file->f_mapping;

	int ret = filemap_fdatawrite_range(mapping, offset, end);



	if (ret)

		return ret;

	filemap_fdatawait_range_keep_errors(mapping, offset, end);

	return 0;

}



/*

 * Commit all pending writes to stable storage.

 *
@@ -1153,9 +1166,10 @@ nfsd_commit(struct svc_rqst *rqstp, struct svc_fh *fhp, 
	if (err)

		goto out;

	if (EX_ISSYNC(fhp->fh_export)) {

		int err2;

		int err2 = nfsd_filemap_write_and_wait_range(nf, offset, end);



		down_write(&nf->nf_rwsem);

		if (!err2)

			err2 = vfs_fsync_range(nf->nf_file, offset, end, 0);

		switch (err2) {

		case 0: