Commit d1205f87 authored by Chuck Lever's avatar Chuck Lever Committed by Trond Myklebust

NFS: NFSv4 readdir loses entries

On recent 2.6.38-rc kernels, connectathon basic test 6 fails on
NFSv4 mounts of OpenSolaris with something like:

> ./test6: readdir
> 	./test6: (/mnt/klimt/matisse.test) didn't read expected 'file.12' dir entry, pass 0
> 	./test6: (/mnt/klimt/matisse.test) didn't read expected 'file.82' dir entry, pass 0
> 	./test6: (/mnt/klimt/matisse.test) didn't read expected 'file.164' dir entry, pass 0
> 	./test6: (/mnt/klimt/matisse.test) Test failed with 3 errors
> basic tests failed
> Tests failed, leaving /mnt/klimt mounted
> [cel@matisse cthon04]$

I narrowed the problem down to nfs4_decode_dirent() reporting that the
decode buffer had overflowed while decoding the entries for those
missing files.

verify_attr_len() assumes both it's pointer arguments reside on the
same page.  When these arguments point to locations on two different
pages, verify_attr_len() can report false errors.  This can happen now
that a large NFSv4 readdir result can span pages.

We have reasonably good checking in nfs4_decode_dirent() anyway, so
it should be safe to simply remove the extra checking.

At a guess, this was introduced by commit 6650239a, "NFS: Don't use
vm_map_ram() in readdir".

Cc: stable@kernel.org [2.6.37]
Signed-off-by: default avatarChuck Lever <chuck.lever@oracle.com>
Signed-off-by: default avatarTrond Myklebust <Trond.Myklebust@netapp.com>
parent c08e76d0
......@@ -6132,9 +6132,6 @@ int nfs4_decode_dirent(struct xdr_stream *xdr, struct nfs_entry *entry,
if (entry->fattr->valid & NFS_ATTR_FATTR_TYPE)
entry->d_type = nfs_umode_to_dtype(entry->fattr->mode);
if (verify_attr_len(xdr, p, len) < 0)
goto out_overflow;
return 0;
out_overflow:
......
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