[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>

1 files changed, 35 insertions, 35 deletions

diff --git a/fs/nfs_common/nfsacl.c b/fs/nfs_common/nfsacl.c
index 251e5a1bb1c4..0c2be8c0307d 100644
--- 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;