Hi Eryu,
On 07/24/2017 10:19 AM, Eryu Guan wrote:
> Hi all,
>
> I saw a new NFS failure in 4.13-rc2 kernel when running fstests
> generic/126 on NFSv4 mounts, 4.13-rc1 kernel passed the same test.
>
> git bisect pointed the first bad to commit bd8b2441742b.
>
> commit bd8b2441742b49c76bec707757bd9c028ea9838e
> Author: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
> Date: Tue Jul 11 17:54:34 2017 -0400
>
> NFS: Store the raw NFS access mask in the inode's access cache
>
> Signed-off-by: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
> Signed-off-by: Anna Schumaker <Anna.Schumaker@xxxxxxxxxx>
>
> I can reproduce it manually with these steps:
>
> mount -t nfs -o vers=4.1 server:/export /mnt/nfs
> cp /usr/bin/ls /mnt/nfs
> chmod 001 /mnt/nfs/ls
> chown 99:99 /mnt/nfs/ls
> su testuser -c "/mnt/nfs/ls"
>
> (testuser uid and gid are not 99.)
>
> The last command got permission denied with 4.13-rc2.
Thanks for letting me know! I think I see the problem: the patch changed how the
access system call is cached but didn't update caching for NFSv4 opens (which is why
v3 still passes). Does this patch help?
diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index e1a26c653e78..4893c9f9829b 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -2250,16 +2250,16 @@ static int nfs4_opendata_access(struct rpc_cred *cred,
*/
if (openflags & __FMODE_EXEC) {
/* ONLY check for exec rights */
- mask = MAY_EXEC;
+ mask = NFS4_ACCESS_EXECUTE;
} else if ((fmode & FMODE_READ) && !opendata->file_created)
- mask = MAY_READ;
+ mask = NFS4_ACCESS_READ;
cache.cred = cred;
cache.jiffies = jiffies;
nfs_access_set_mask(&cache, opendata->o_res.access_result);
nfs_access_add_cache(state->inode, &cache);
- if ((mask & ~cache.mask & (MAY_READ | MAY_EXEC)) == 0)
+ if ((mask & ~cache.mask & (NFS4_ACCESS_READ | NFS4_ACCESS_EXECUTE)) == 0)
return 0;
return -EACCES;
>
> Thanks,
> Eryu
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