Merge tag 'v2.6.38' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6

[mv-sheeva.git] / fs / nfs_common / nfsacl.c

diff --git a/fs/nfs_common/nfsacl.c b/fs/nfs_common/nfsacl.c
index fc1c52571c03ea9eaf0d4e96a4026f119cd026e9..84c27d69d421e494c2c41359f06dd02eb2c32960 100644 (file)
--- a/fs/nfs_common/nfsacl.c
+++ b/fs/nfs_common/nfsacl.c
@@ -42,6 +42,11 @@ struct nfsacl_encode_desc {
        gid_t gid;
 };
 
+struct nfsacl_simple_acl {
+       struct posix_acl acl;
+       struct posix_acl_entry ace[4];
+};
+
 static int
 xdr_nfsace_encode(struct xdr_array2_desc *desc, void *elem)
 {
@@ -72,9 +77,20 @@ xdr_nfsace_encode(struct xdr_array2_desc *desc, void *elem)
        return 0;
 }
 
-unsigned int
-nfsacl_encode(struct xdr_buf *buf, unsigned int base, struct inode *inode,
-             struct posix_acl *acl, int encode_entries, int typeflag)
+/**
+ * nfsacl_encode - Encode an NFSv3 ACL
+ *
+ * @buf: destination xdr_buf to contain XDR encoded ACL
+ * @base: byte offset in xdr_buf where XDR'd ACL begins
+ * @inode: inode of file whose ACL this is
+ * @acl: posix_acl to encode
+ * @encode_entries: whether to encode ACEs as well
+ * @typeflag: ACL type: NFS_ACL_DEFAULT or zero
+ *
+ * Returns size of encoded ACL in bytes or a negative errno value.
+ */
+int nfsacl_encode(struct xdr_buf *buf, unsigned int base, struct inode *inode,
+                 struct posix_acl *acl, int encode_entries, int typeflag)
 {
        int entries = (acl && acl->a_count) ? max_t(int, acl->a_count, 4) : 0;
        struct nfsacl_encode_desc nfsacl_desc = {
@@ -88,17 +104,22 @@ nfsacl_encode(struct xdr_buf *buf, unsigned int base, struct inode *inode,
                .uid = inode->i_uid,
                .gid = inode->i_gid,
        };
+       struct nfsacl_simple_acl aclbuf;
        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;
+               struct posix_acl *acl2 = &aclbuf.acl;
+
+               /* Avoid the use of posix_acl_alloc().  nfsacl_encode() is
+                * invoked in contexts where a memory allocation failure is
+                * fatal.  Fortunately this fake ACL is small enough to
+                * construct on the stack. */
+               memset(acl2, 0, sizeof(acl2));
+               posix_acl_init(acl2, 4);
+
                /* Insert entries in canonical order: other orders seem
                 to confuse Solaris VxFS. */
                acl2->a_entries[0] = acl->a_entries[0];  /* ACL_USER_OBJ */
@@ -109,8 +130,6 @@ nfsacl_encode(struct xdr_buf *buf, unsigned int base, struct inode *inode,
                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;
@@ -224,9 +243,18 @@ posix_acl_from_nfsacl(struct posix_acl *acl)
        return 0;
 }
 
-unsigned int
-nfsacl_decode(struct xdr_buf *buf, unsigned int base, unsigned int *aclcnt,
-             struct posix_acl **pacl)
+/**
+ * nfsacl_decode - Decode an NFSv3 ACL
+ *
+ * @buf: xdr_buf containing XDR'd ACL data to decode
+ * @base: byte offset in xdr_buf where XDR'd ACL begins
+ * @aclcnt: count of ACEs in decoded posix_acl
+ * @pacl: buffer in which to place decoded posix_acl
+ *
+ * Returns the length of the decoded ACL in bytes, or a negative errno value.
+ */
+int nfsacl_decode(struct xdr_buf *buf, unsigned int base, unsigned int *aclcnt,
+                 struct posix_acl **pacl)
 {
        struct nfsacl_decode_desc nfsacl_desc = {
                .desc = {