Patch "NFSD: Save location of NFSv4 COMPOUND status" has been added to the 5.15-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    NFSD: Save location of NFSv4 COMPOUND status

to the 5.15-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     nfsd-save-location-of-nfsv4-compound-status.patch
and it can be found in the queue-5.15 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit d568a1615f0155001b0decebbd94d8563f20217b
Author: Chuck Lever <chuck.lever@xxxxxxxxxx>
Date:   Wed Oct 13 10:40:59 2021 -0400

    NFSD: Save location of NFSv4 COMPOUND status
    
    [ Upstream commit 3b0ebb255fdc49a3d340846deebf045ef58ec744 ]
    
    Refactor: Currently nfs4svc_encode_compoundres() relies on the NFS
    dispatcher to pass in the buffer location of the COMPOUND status.
    Instead, save that buffer location in struct nfsd4_compoundres.
    
    The compound tag follows immediately after.
    
    Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
    Signed-off-by: J. Bruce Fields <bfields@xxxxxxxxxx>
    Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>

diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
index bc7ae9a8604ec..002473c59fc6f 100644
--- a/fs/nfsd/nfs4proc.c
+++ b/fs/nfsd/nfs4proc.c
@@ -2462,11 +2462,11 @@ nfsd4_proc_compound(struct svc_rqst *rqstp)
 	__be32		status;
 
 	resp->xdr = &rqstp->rq_res_stream;
+	resp->statusp = resp->xdr->p;
 
 	/* reserve space for: NFS status code */
 	xdr_reserve_space(resp->xdr, XDR_UNIT);
 
-	resp->tagp = resp->xdr->p;
 	/* reserve space for: taglen, tag, and opcnt */
 	xdr_reserve_space(resp->xdr, XDR_UNIT * 2 + args->taglen);
 	resp->taglen = args->taglen;
diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index 9fcaf5f93f75d..e94f57f174f12 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -5436,11 +5436,16 @@ nfs4svc_encode_compoundres(struct svc_rqst *rqstp, __be32 *p)
 	WARN_ON_ONCE(buf->len != buf->head[0].iov_len + buf->page_len +
 				 buf->tail[0].iov_len);
 
-	*p = resp->cstate.status;
+	/*
+	 * Send buffer space for the following items is reserved
+	 * at the top of nfsd4_proc_compound().
+	 */
+	p = resp->statusp;
+
+	*p++ = resp->cstate.status;
 
 	rqstp->rq_next_page = resp->xdr->page_ptr + 1;
 
-	p = resp->tagp;
 	*p++ = htonl(resp->taglen);
 	memcpy(p, resp->tag, resp->taglen);
 	p += XDR_QUADLEN(resp->taglen);
diff --git a/fs/nfsd/xdr4.h b/fs/nfsd/xdr4.h
index 50242d8cd09e8..f20c1ae97fec5 100644
--- a/fs/nfsd/xdr4.h
+++ b/fs/nfsd/xdr4.h
@@ -703,10 +703,11 @@ struct nfsd4_compoundres {
 	struct xdr_stream		*xdr;
 	struct svc_rqst *		rqstp;
 
+	__be32				*statusp;
 	u32				taglen;
 	char *				tag;
 	u32				opcnt;
-	__be32 *			tagp; /* tag, opcount encode location */
+
 	struct nfsd4_compound_state	cstate;
 };