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: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
1 file changed
