linux-kernel - [PATCH] NFSv3: FIx bug when using chacl and chmod to change acl

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Date:   Wed, 25 Dec 2019 11:37:57 +0800
From:   Su Yanjun <suyanjun218@...il.com>
To:     Trond Myklebust <trond.myklebust@...merspace.com>,
        Anna Schumaker <anna.schumaker@...app.com>
Cc:     "linux-nfs@...r.kernel.org" <linux-nfs@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: [PATCH] NFSv3: FIx bug when using chacl and chmod to change acl

We find a bug when running test under nfsv3  as below.
1)
chacl u::r--,g::rwx,o:rw- file1
2)
chmod u+w file1
3)
chacl -l file1

We expect u::rw-, but it shows u::r--, more likely it returns the
cached acl in inode.

We dig the code find that the code path is different.

chacl->..->__nfs3_proc_setacls->nfs_zap_acl_cache
Then nfs_zap_acl_cache clears the NFS_INO_INVALID_ACL in
NFS_I(inode)->cache_validity.

chmod->..->nfs3_proc_setattr
Because NFS_INO_INVALID_ACL has been cleared by chacl path,
nfs_zap_acl_cache wont be called.

nfs_setattr_update_inode will set NFS_INO_INVALID_ACL so let it
before nfs_zap_acl_cache call.

Signed-off-by: Su Yanjun <suyanjun218@...il.com>
---
 fs/nfs/nfs3proc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/nfs/nfs3proc.c b/fs/nfs/nfs3proc.c
index 9eb2f1a503ab..6d736f0ac811 100644
--- a/fs/nfs/nfs3proc.c
+++ b/fs/nfs/nfs3proc.c
@@ -140,9 +140,9 @@ nfs3_proc_setattr(struct dentry *dentry, struct nfs_fattr *fattr,
     nfs_fattr_init(fattr);
     status = rpc_call_sync(NFS_CLIENT(inode), &msg, 0);
     if (status == 0) {
+        nfs_setattr_update_inode(inode, sattr, fattr);
         if (NFS_I(inode)->cache_validity & NFS_INO_INVALID_ACL)
             nfs_zap_acl_cache(inode);
-        nfs_setattr_update_inode(inode, sattr, fattr);
     }
     dprintk("NFS reply setattr: %d\n", status);
     return status;

-- 
2.17.1