2013-03-03 09:02:24

by Yanchuan Nian

Subject: [PATCH] nfsd: Correct read access checking

NFS4_SHARE_ACCESS_WRITE should not be tested in access_permit_read() for this
function just tests read permission, so remove it.

Signed-off-by: Yanchuan Nian <[email protected]>
---
fs/nfsd/nfs4state.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 16d39c6..75c873d 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -3322,8 +3322,7 @@ static inline int
access_permit_read(struct nfs4_ol_stateid *stp)
{
return test_access(NFS4_SHARE_ACCESS_READ, stp) ||
- test_access(NFS4_SHARE_ACCESS_BOTH, stp) ||
- test_access(NFS4_SHARE_ACCESS_WRITE, stp);
+ test_access(NFS4_SHARE_ACCESS_BOTH, stp);
}

static inline int
--
1.8.0.1

2013-03-05 21:11:05

by J. Bruce Fields

Subject: Re: [PATCH] nfsd: Correct read access checking

On Sun, Mar 03, 2013 at 05:02:11PM +0800, Yanchuan Nian wrote:
> NFS4_SHARE_ACCESS_WRITE should not be tested in access_permit_read() for this
> function just tests read permission, so remove it.
>
> Signed-off-by: Yanchuan Nian <[email protected]>
> ---
> fs/nfsd/nfs4state.c | 3 +--
> 1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
> index 16d39c6..75c873d 100644
> --- a/fs/nfsd/nfs4state.c
> +++ b/fs/nfsd/nfs4state.c
> @@ -3322,8 +3322,7 @@ static inline int
> access_permit_read(struct nfs4_ol_stateid *stp)
> {
> return test_access(NFS4_SHARE_ACCESS_READ, stp) ||
> - test_access(NFS4_SHARE_ACCESS_BOTH, stp) ||
> - test_access(NFS4_SHARE_ACCESS_WRITE, stp);
> + test_access(NFS4_SHARE_ACCESS_BOTH, stp);
> }

This was introduced by a patch from 2005:

[PATCH] nfsd4: allow read on open for write

The rfc recommends allowing read using stateid's from opens that only
requested write access, as clients may in some cases be unable to write
without doing reads.

So I think it's correct.

That said, I don't understand why we still have this function at all:
can it ever return anything other than true?

--b.