Commit 43a9aa64 authored Jul 06, 2010 by Chuck Lever Committed by J. Bruce Fields Jul 07, 2010

NFSD: Fill in WCC data for REMOVE, RMDIR, MKNOD, and MKDIR



Some well-known NFSv3 clients drop their directory entry caches when
they receive replies with no WCC data.  Without this data, they
employ extra READ, LOOKUP, and GETATTR requests to ensure their
directory entry caches are up to date, causing performance to suffer
needlessly.

In order to return WCC data, our server has to have both the pre-op
and the post-op attribute data on hand when a reply is XDR encoded.
The pre-op data is filled in when the incoming fh is locked, and the
post-op data is filled in when the fh is unlocked.

Unfortunately, for REMOVE, RMDIR, MKNOD, and MKDIR, the directory fh
is not unlocked until well after the reply has been XDR encoded.  This
means that encode_wcc_data() does not have wcc_data for the parent
directory, so none is returned to the client after these operations
complete.

By unlocking the parent directory fh immediately after the internal
operations for each NFS procedure is complete, the post-op data is
filled in before XDR encoding starts, so it can be returned to the
client properly.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>

parent 6a85d6c7

fs/nfsd/nfs3proc.c

+4 −2

Original line number	Diff line number	Diff line
		@@ -271,7 +271,7 @@ nfsd3_proc_mkdir(struct svc_rqst rqstp, struct nfsd3_createargs argp,
		fh_init(&resp->fh, NFS3_FHSIZE);
		nfserr = nfsd_create(rqstp, &resp->dirfh, argp->name, argp->len,
		&argp->attrs, S_IFDIR, 0, &resp->fh);

		fh_unlock(&resp->dirfh);
		RETURN_STATUS(nfserr);
		}

		@@ -327,7 +327,7 @@ nfsd3_proc_mknod(struct svc_rqst rqstp, struct nfsd3_mknodargs argp,
		type = nfs3_ftypes[argp->ftype];
		nfserr = nfsd_create(rqstp, &resp->dirfh, argp->name, argp->len,
		&argp->attrs, type, rdev, &resp->fh);

		fh_unlock(&resp->dirfh);
		RETURN_STATUS(nfserr);
		}

		@@ -348,6 +348,7 @@ nfsd3_proc_remove(struct svc_rqst rqstp, struct nfsd3_diropargs argp,
		/* Unlink. -S_IFDIR means file must not be a directory */
		fh_copy(&resp->fh, &argp->fh);
		nfserr = nfsd_unlink(rqstp, &resp->fh, -S_IFDIR, argp->name, argp->len);
		fh_unlock(&resp->fh);
		RETURN_STATUS(nfserr);
		}

		@@ -367,6 +368,7 @@ nfsd3_proc_rmdir(struct svc_rqst rqstp, struct nfsd3_diropargs argp,

		fh_copy(&resp->fh, &argp->fh);
		nfserr = nfsd_unlink(rqstp, &resp->fh, S_IFDIR, argp->name, argp->len);
		fh_unlock(&resp->fh);
		RETURN_STATUS(nfserr);
		}

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