FAILED: patch "[PATCH] NFSD: COMMIT operations must not return NFS?ERR_INVAL" failed to apply to 4.19-stable tree

The patch below does not apply to the 4.19-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 3f965021c8bc38965ecb1924f570c4842b33d408 Mon Sep 17 00:00:00 2001
From: Chuck Lever <[email protected]>
Date: Mon, 24 Jan 2022 15:50:31 -0500
Subject: [PATCH] NFSD: COMMIT operations must not return NFS?ERR_INVAL

Since, well, forever, the Linux NFS server's nfsd_commit() function has returned nfserr_inval when the passed-in byte range arguments were non-sensical.

However, according to RFC 1813 section 3.3.21, NFSv3 COMMIT requests are permitted to return only the following non-zero status codes:

NFS3ERR_IO
NFS3ERR_STALE
NFS3ERR_BADHANDLE
NFS3ERR_SERVERFAULT

NFS3ERR_INVAL is not included in that list. Likewise, NFS4ERR_INVAL is not listed in the COMMIT row of Table 6 in RFC 8881.

RFC 7530 does permit COMMIT to return NFS4ERR_INVAL, but does not specify when it can or should be used.

Instead of dropping or failing a COMMIT request in a byte range that is not supported, turn it into a valid request by treating one or both arguments as zero. Offset zero means start-of-file, count zero means until-end-of-file, so we only ever extend the commit range. NFS servers are always allowed to commit more and sooner than requested.

The range check is no longer bounded by NFS_OFFSET_MAX, but rather by the value that is returned in the maxfilesize field of the NFSv3 FSINFO procedure or the NFSv4 maxfilesize file attribute.

Note that this change results in a new pynfs failure:

CMT4     st_commit.testCommitOverflow                             : RUNNING
CMT4     st_commit.testCommitOverflow                             : FAILURE

COMMIT with offset + count overflow should return NFS4ERR_INVAL, instead got NFS4_OK

IMO the test is not correct as written: RFC 8881 does not allow the COMMIT operation to return NFS4ERR_INVAL.

index aca38ed1526e..52ad1972cc33 100644
@@ -663,15 +663,9 @@ nfsd3_proc_commit(struct svc_rqst *rqstp)
 				argp->count,
 				(unsigned long long) argp->offset);
 
-	if (argp->offset > NFS_OFFSET_MAX) {
-		resp->status = nfserr_inval;
-		goto out;
-	}
-
 	fh_copy(&resp->fh, &argp->fh);
 	resp->status = nfsd_commit(rqstp, &resp->fh, argp->offset,
 				   argp->count, resp->verf);
-out:
 	return rpc_success;
 }
 

index 9f56dcb22ff7..2c43d10e3cab 100644
@@ -74,8 +74,8 @@ __be32		do_nfsd_create(struct svc_rqst *, struct svc_fh *,
 				char *name, int len, struct iattr *attrs,
 				struct svc_fh *res, int createmode,
 				u32 *verifier, bool *truncp, bool *created);
-__be32		nfsd_commit(struct svc_rqst *, struct svc_fh *,
-				loff_t, unsigned long, __be32 *verf);
+__be32		nfsd_commit(struct svc_rqst *rqst, struct svc_fh *fhp,
+				u64 offset, u32 count, __be32 *verf);
 #endif /* CONFIG_NFSD_V3 */
 #ifdef CONFIG_NFSD_V4
 __be32		nfsd_getxattr(struct svc_rqst *rqstp, struct svc_fh *fhp,