Re: [ 53/62] nfsd: fix b0rken error value for setattr on read-only mount

[Jonathan Nieder <jrnieder@gmail.com>]

Greg KH wrote:

> 3.3-stable review patch.
[...]
> commit 96f6f98501196d46ce52c2697dd758d9300c63f5 upstream.
>
> ..._want_write() returns -EROFS on failure, _not_ an NFS error value.

Here's the corresponding change for kernels without

	static inline int fh_want_write(struct svc_fh *fh)
	{
		return mnt_want_write(fh->fh_export->ex_path.mnt);
	}

from v3.3-rc1~170^2~81 ("new helpers: fh_{want,drop}_write()"),
such as the 3.0.y kernel.  Thoughts and testing welcome as usual.

-- >8 --
From: Al Viro <viro@zeniv.linux.org.uk>
Date: Thu, 12 Apr 2012 23:47:00 -0400

commit 96f6f98501196d46ce52c2697dd758d9300c63f5 upstream.

..._want_write() returns -EROFS on failure, _not_ an NFS error value.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
---
Thanks,
Jonathan

 fs/nfsd/nfs4proc.c |    7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
index 0b8830c9de73..d06a02c1b1a3 100644
--- a/fs/nfsd/nfs4proc.c
+++ b/fs/nfsd/nfs4proc.c
@@ -812,6 +812,7 @@ nfsd4_setattr(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
 	      struct nfsd4_setattr *setattr)
 {
 	__be32 status = nfs_ok;
+	int err;
 
 	if (setattr->sa_iattr.ia_valid & ATTR_SIZE) {
 		nfs4_lock_state();
@@ -823,9 +824,9 @@ nfsd4_setattr(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
 			return status;
 		}
 	}
-	status = mnt_want_write(cstate->current_fh.fh_export->ex_path.mnt);
-	if (status)
-		return status;
+	err = mnt_want_write(cstate->current_fh.fh_export->ex_path.mnt);
+	if (err)
+		return nfserrno(err);
 	status = nfs_ok;
 
 	status = check_attr_support(rqstp, cstate, setattr->sa_bmval,
-- 
1.7.10