[PATCH] nfsacl: Solaris VxFS compatibility fix

Here is a compatibility fix between Linux and Solaris when used with VxFS
filesystems: Solaris usually accepts acl entries in any order, but with
VxFS it replies with NFSERR_INVAL when it sees a four-entry acl that is not
in canonical form.  It may also fail with other non-canonical acls -- I
can't tell, because that case never triggers: We only send non-canonical
acls when we fake up an ACL_MASK entry.

Instead of adding fake ACL_MASK entries at the end, inserting them in the
correct position makes Solaris+VxFS happy.  The Linux client and server
sides don't care about entry order.  The three-entry-acl special case in
which we need a fake ACL_MASK entry was handled in xdr_nfsace_encode.  The
patch moves this into nfsacl_encode.

Signed-off-by: Andreas Gruenbacher <agruen@suse.de>
Acked-by: Trond Myklebust <trond.myklebust@fys.uio.no>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/fs/nfs_common/nfsacl.c b/fs/nfs_common/nfsacl.c
index 251e5a1..0c2be8c 100644 (file)
--- a/fs/nfs_common/nfsacl.c
+++ b/fs/nfs_common/nfsacl.c
@@ -48,43 +48,26 @@ xdr_nfsace_encode(struct xdr_array2_desc *desc, void *elem)
                (struct nfsacl_encode_desc *) desc;
        u32 *p = (u32 *) elem;
 
-       if (nfsacl_desc->count < nfsacl_desc->acl->a_count) {
-               struct posix_acl_entry *entry =
-                       &nfsacl_desc->acl->a_entries[nfsacl_desc->count++];
+       struct posix_acl_entry *entry =
+               &nfsacl_desc->acl->a_entries[nfsacl_desc->count++];
 
-               *p++ = htonl(entry->e_tag | nfsacl_desc->typeflag);
-               switch(entry->e_tag) {
-                       case ACL_USER_OBJ:
-                               *p++ = htonl(nfsacl_desc->uid);
-                               break;
-                       case ACL_GROUP_OBJ:
-                               *p++ = htonl(nfsacl_desc->gid);
-                               break;
-                       case ACL_USER:
-                       case ACL_GROUP:
-                               *p++ = htonl(entry->e_id);
-                               break;
-                       default:  /* Solaris depends on that! */
-                               *p++ = 0;
-                               break;
-               }
-               *p++ = htonl(entry->e_perm & S_IRWXO);
-       } else {
-               const struct posix_acl_entry *pa, *pe;
-               int group_obj_perm = ACL_READ|ACL_WRITE|ACL_EXECUTE;
-
-               FOREACH_ACL_ENTRY(pa, nfsacl_desc->acl, pe) {
-                       if (pa->e_tag == ACL_GROUP_OBJ) {
-                               group_obj_perm = pa->e_perm & S_IRWXO;
-                               break;
-                       }
-               }
-               /* fake up ACL_MASK entry */
-               *p++ = htonl(ACL_MASK | nfsacl_desc->typeflag);
-               *p++ = htonl(0);
-               *p++ = htonl(group_obj_perm);
+       *p++ = htonl(entry->e_tag | nfsacl_desc->typeflag);
+       switch(entry->e_tag) {
+               case ACL_USER_OBJ:
+                       *p++ = htonl(nfsacl_desc->uid);
+                       break;
+               case ACL_GROUP_OBJ:
+                       *p++ = htonl(nfsacl_desc->gid);
+                       break;
+               case ACL_USER:
+               case ACL_GROUP:
+                       *p++ = htonl(entry->e_id);
+                       break;
+               default:  /* Solaris depends on that! */
+                       *p++ = 0;
+                       break;
        }
-
+       *p++ = htonl(entry->e_perm & S_IRWXO);
        return 0;
 }
 
@@ -105,11 +88,28 @@ nfsacl_encode(struct xdr_buf *buf, unsigned int base, struct inode *inode,
                .gid = inode->i_gid,
        };
        int err;
+       struct posix_acl *acl2 = NULL;
 
        if (entries > NFS_ACL_MAX_ENTRIES ||
            xdr_encode_word(buf, base, entries))
                return -EINVAL;
+       if (encode_entries && acl && acl->a_count == 3) {
+               /* Fake up an ACL_MASK entry. */
+               acl2 = posix_acl_alloc(4, GFP_KERNEL);
+               if (!acl2)
+                       return -ENOMEM;
+               /* Insert entries in canonical order: other orders seem
+                to confuse Solaris VxFS. */
+               acl2->a_entries[0] = acl->a_entries[0];  /* ACL_USER_OBJ */
+               acl2->a_entries[1] = acl->a_entries[1];  /* ACL_GROUP_OBJ */
+               acl2->a_entries[2] = acl->a_entries[1];  /* ACL_MASK */
+               acl2->a_entries[2].e_tag = ACL_MASK;
+               acl2->a_entries[3] = acl->a_entries[2];  /* ACL_OTHER */
+               nfsacl_desc.acl = acl2;
+       }
        err = xdr_encode_array2(buf, base + 4, &nfsacl_desc.desc);
+       if (acl2)
+               posix_acl_release(acl2);
        if (!err)
                err = 8 + nfsacl_desc.desc.elem_size *
                          nfsacl_desc.desc.array_len;