xfs: move the legacy xfs_attr_list to xfs_ioctl.c

The old xfs_attr_list code is only used by the attrlist by handle
ioctl.  Move it to xfs_ioctl.c with its user.  Also move the
attrlist and attrlist_ent structure to xfs_fs.h, as they are exposed
user ABIs.  They are used through libattr headers with the same name
by at least xfsdump.  Also document this relation so that it doesn't
require a research project to figure out.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Chandan Rajendra <chandanrlinux@gmail.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

fs/xfs/xfs_ioctl.c

@@ -294,6 +294,111 @@ xfs_readlink_by_handle(
 	return error;
 }
 
+/*
+ * Format an attribute and copy it out to the user's buffer.
+ * Take care to check values and protect against them changing later,
+ * we may be reading them directly out of a user buffer.
+ */
+static void
+xfs_ioc_attr_put_listent(
+	struct xfs_attr_list_context *context,
+	int			flags,
+	unsigned char		*name,
+	int			namelen,
+	int			valuelen)
+{
+	struct xfs_attrlist	*alist = context->buffer;
+	struct xfs_attrlist_ent	*aep;
+	int			arraytop;
+
+	ASSERT(!context->seen_enough);
+	ASSERT(context->count >= 0);
+	ASSERT(context->count < (ATTR_MAX_VALUELEN/8));
+	ASSERT(context->firstu >= sizeof(*alist));
+	ASSERT(context->firstu <= context->bufsize);
+
+	/*
+	 * Only list entries in the right namespace.
+	 */
+	if (((context->flags & ATTR_SECURE) == 0) !=
+	    ((flags & XFS_ATTR_SECURE) == 0))
+		return;
+	if (((context->flags & ATTR_ROOT) == 0) !=
+	    ((flags & XFS_ATTR_ROOT) == 0))
+		return;
+
+	arraytop = sizeof(*alist) +
+			context->count * sizeof(alist->al_offset[0]);
+
+	/* decrement by the actual bytes used by the attr */
+	context->firstu -= round_up(offsetof(struct xfs_attrlist_ent, a_name) +
+			namelen + 1, sizeof(uint32_t));
+	if (context->firstu < arraytop) {
+		trace_xfs_attr_list_full(context);
+		alist->al_more = 1;
+		context->seen_enough = 1;
+		return;
+	}
+
+	aep = context->buffer + context->firstu;
+	aep->a_valuelen = valuelen;
+	memcpy(aep->a_name, name, namelen);
+	aep->a_name[namelen] = 0;
+	alist->al_offset[context->count++] = context->firstu;
+	alist->al_count = context->count;
+	trace_xfs_attr_list_add(context);
+}
+
+int
+xfs_ioc_attr_list(
+	struct xfs_inode		*dp,
+	char				*buffer,
+	int				bufsize,
+	int				flags,
+	struct attrlist_cursor_kern	*cursor)
+{
+	struct xfs_attr_list_context	context;
+	struct xfs_attrlist		*alist;
+	int				error;
+
+	/*
+	 * Validate the cursor.
+	 */
+	if (cursor->pad1 || cursor->pad2)
+		return -EINVAL;
+	if ((cursor->initted == 0) &&
+	    (cursor->hashval || cursor->blkno || cursor->offset))
+		return -EINVAL;
+
+	/*
+	 * Check for a properly aligned buffer.
+	 */
+	if (((long)buffer) & (sizeof(int)-1))
+		return -EFAULT;
+
+	/*
+	 * Initialize the output buffer.
+	 */
+	memset(&context, 0, sizeof(context));
+	context.dp = dp;
+	context.cursor = cursor;
+	context.resynch = 1;
+	context.flags = flags;
+	context.buffer = buffer;
+	context.bufsize = (bufsize & ~(sizeof(int)-1));  /* align */
+	context.firstu = context.bufsize;
+	context.put_listent = xfs_ioc_attr_put_listent;
+
+	alist = context.buffer;
+	alist->al_count = 0;
+	alist->al_more = 0;
+	alist->al_offset[0] = context.bufsize;
+
+	error = xfs_attr_list_int(&context);
+	ASSERT(error <= 0);
+	return error;
+}
+
 STATIC int
 xfs_attrlist_by_handle(
 	struct file		*parfilp,
@@ -310,7 +415,7 @@ xfs_attrlist_by_handle(
 		return -EPERM;
 	if (copy_from_user(&al_hreq, arg, sizeof(xfs_fsop_attrlist_handlereq_t)))
 		return -EFAULT;
-	if (al_hreq.buflen < sizeof(struct attrlist) ||
+	if (al_hreq.buflen < sizeof(struct xfs_attrlist) ||
 	    al_hreq.buflen > XFS_XATTR_LIST_MAX)
 		return -EINVAL;
 
@@ -331,7 +436,7 @@ xfs_attrlist_by_handle(
 		goto out_dput;
 
 	cursor = (attrlist_cursor_kern_t *)&al_hreq.pos;
-	error = xfs_attr_list(XFS_I(d_inode(dentry)), kbuf, al_hreq.buflen,
+	error = xfs_ioc_attr_list(XFS_I(d_inode(dentry)), kbuf, al_hreq.buflen,
 					al_hreq.flags, cursor);
 	if (error)
 		goto out_kfree;