1 files changed, 516 insertions, 0 deletions

diff --git a/fs/xfs/scrub/btree.c b/fs/xfs/scrub/btree.c
new file mode 100644
index 000000000000..df0766132ace
--- /dev/null
+++ b/fs/xfs/scrub/btree.c
@@ -0,0 +1,516 @@
+/*
+ * Copyright (C) 2017 Oracle.  All Rights Reserved.
+ *
+ * Author: Darrick J. Wong <darrick.wong@oracle.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it would be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write the Free Software Foundation,
+ * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+#include "xfs.h"
+#include "xfs_fs.h"
+#include "xfs_shared.h"
+#include "xfs_format.h"
+#include "xfs_trans_resv.h"
+#include "xfs_mount.h"
+#include "xfs_defer.h"
+#include "xfs_btree.h"
+#include "xfs_bit.h"
+#include "xfs_log_format.h"
+#include "xfs_trans.h"
+#include "xfs_sb.h"
+#include "xfs_inode.h"
+#include "xfs_alloc.h"
+#include "scrub/scrub.h"
+#include "scrub/common.h"
+#include "scrub/btree.h"
+#include "scrub/trace.h"
+
+/* btree scrubbing */
+
+/*
+ * Check for btree operation errors.  See the section about handling
+ * operational errors in common.c.
+ */
+bool
+xfs_scrub_btree_process_error(
+	struct xfs_scrub_context	*sc,
+	struct xfs_btree_cur		*cur,
+	int				level,
+	int				*error)
+{
+	if (*error == 0)
+		return true;
+
+	switch (*error) {
+	case -EDEADLOCK:
+		/* Used to restart an op with deadlock avoidance. */
+		trace_xfs_scrub_deadlock_retry(sc->ip, sc->sm, *error);
+		break;
+	case -EFSBADCRC:
+	case -EFSCORRUPTED:
+		/* Note the badness but don't abort. */
+		sc->sm->sm_flags |= XFS_SCRUB_OFLAG_CORRUPT;
+		*error = 0;
+		/* fall through */
+	default:
+		if (cur->bc_flags & XFS_BTREE_ROOT_IN_INODE)
+			trace_xfs_scrub_ifork_btree_op_error(sc, cur, level,
+					*error, __return_address);
+		else
+			trace_xfs_scrub_btree_op_error(sc, cur, level,
+					*error, __return_address);
+		break;
+	}
+	return false;
+}
+
+/* Record btree block corruption. */
+void
+xfs_scrub_btree_set_corrupt(
+	struct xfs_scrub_context	*sc,
+	struct xfs_btree_cur		*cur,
+	int				level)
+{
+	sc->sm->sm_flags |= XFS_SCRUB_OFLAG_CORRUPT;
+
+	if (cur->bc_flags & XFS_BTREE_ROOT_IN_INODE)
+		trace_xfs_scrub_ifork_btree_error(sc, cur, level,
+				__return_address);
+	else
+		trace_xfs_scrub_btree_error(sc, cur, level,
+				__return_address);
+}
+
+/*
+ * Make sure this record is in order and doesn't stray outside of the parent
+ * keys.
+ */
+STATIC void
+xfs_scrub_btree_rec(
+	struct xfs_scrub_btree	*bs)
+{
+	struct xfs_btree_cur	*cur = bs->cur;
+	union xfs_btree_rec	*rec;
+	union xfs_btree_key	key;
+	union xfs_btree_key	hkey;
+	union xfs_btree_key	*keyp;
+	struct xfs_btree_block	*block;
+	struct xfs_btree_block	*keyblock;
+	struct xfs_buf		*bp;
+
+	block = xfs_btree_get_block(cur, 0, &bp);
+	rec = xfs_btree_rec_addr(cur, cur->bc_ptrs[0], block);
+
+	trace_xfs_scrub_btree_rec(bs->sc, cur, 0);
+
+	/* If this isn't the first record, are they in order? */
+	if (!bs->firstrec && !cur->bc_ops->recs_inorder(cur, &bs->lastrec, rec))
+		xfs_scrub_btree_set_corrupt(bs->sc, cur, 0);
+	bs->firstrec = false;
+	memcpy(&bs->lastrec, rec, cur->bc_ops->rec_len);
+
+	if (cur->bc_nlevels == 1)
+		return;
+
+	/* Is this at least as large as the parent low key? */
+	cur->bc_ops->init_key_from_rec(&key, rec);
+	keyblock = xfs_btree_get_block(cur, 1, &bp);
+	keyp = xfs_btree_key_addr(cur, cur->bc_ptrs[1], keyblock);
+	if (cur->bc_ops->diff_two_keys(cur, &key, keyp) < 0)
+		xfs_scrub_btree_set_corrupt(bs->sc, cur, 1);
+
+	if (!(cur->bc_flags & XFS_BTREE_OVERLAPPING))
+		return;
+
+	/* Is this no larger than the parent high key? */
+	cur->bc_ops->init_high_key_from_rec(&hkey, rec);
+	keyp = xfs_btree_high_key_addr(cur, cur->bc_ptrs[1], keyblock);
+	if (cur->bc_ops->diff_two_keys(cur, keyp, &hkey) < 0)
+		xfs_scrub_btree_set_corrupt(bs->sc, cur, 1);
+}
+
+/*
+ * Make sure this key is in order and doesn't stray outside of the parent
+ * keys.
+ */
+STATIC void
+xfs_scrub_btree_key(
+	struct xfs_scrub_btree	*bs,
+	int			level)
+{
+	struct xfs_btree_cur	*cur = bs->cur;
+	union xfs_btree_key	*key;
+	union xfs_btree_key	*keyp;
+	struct xfs_btree_block	*block;
+	struct xfs_btree_block	*keyblock;
+	struct xfs_buf		*bp;
+
+	block = xfs_btree_get_block(cur, level, &bp);
+	key = xfs_btree_key_addr(cur, cur->bc_ptrs[level], block);
+
+	trace_xfs_scrub_btree_key(bs->sc, cur, level);
+
+	/* If this isn't the first key, are they in order? */
+	if (!bs->firstkey[level] &&
+	    !cur->bc_ops->keys_inorder(cur, &bs->lastkey[level], key))
+		xfs_scrub_btree_set_corrupt(bs->sc, cur, level);
+	bs->firstkey[level] = false;
+	memcpy(&bs->lastkey[level], key, cur->bc_ops->key_len);
+
+	if (level + 1 >= cur->bc_nlevels)
+		return;
+
+	/* Is this at least as large as the parent low key? */
+	keyblock = xfs_btree_get_block(cur, level + 1, &bp);
+	keyp = xfs_btree_key_addr(cur, cur->bc_ptrs[level + 1], keyblock);
+	if (cur->bc_ops->diff_two_keys(cur, key, keyp) < 0)
+		xfs_scrub_btree_set_corrupt(bs->sc, cur, level);
+
+	if (!(cur->bc_flags & XFS_BTREE_OVERLAPPING))
+		return;
+
+	/* Is this no larger than the parent high key? */
+	key = xfs_btree_high_key_addr(cur, cur->bc_ptrs[level], block);
+	keyp = xfs_btree_high_key_addr(cur, cur->bc_ptrs[level + 1], keyblock);
+	if (cur->bc_ops->diff_two_keys(cur, keyp, key) < 0)
+		xfs_scrub_btree_set_corrupt(bs->sc, cur, level);
+}
+
+/*
+ * Check a btree pointer.  Returns true if it's ok to use this pointer.
+ * Callers do not need to set the corrupt flag.
+ */
+static bool
+xfs_scrub_btree_ptr_ok(
+	struct xfs_scrub_btree		*bs,
+	int				level,
+	union xfs_btree_ptr		*ptr)
+{
+	bool				res;
+
+	/* A btree rooted in an inode has no block pointer to the root. */
+	if ((bs->cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) &&
+	    level == bs->cur->bc_nlevels)
+		return true;
+
+	/* Otherwise, check the pointers. */
+	if (bs->cur->bc_flags & XFS_BTREE_LONG_PTRS)
+		res = xfs_btree_check_lptr(bs->cur, be64_to_cpu(ptr->l), level);
+	else
+		res = xfs_btree_check_sptr(bs->cur, be32_to_cpu(ptr->s), level);
+	if (!res)
+		xfs_scrub_btree_set_corrupt(bs->sc, bs->cur, level);
+
+	return res;
+}
+
+/* Check that a btree block's sibling matches what we expect it. */
+STATIC int
+xfs_scrub_btree_block_check_sibling(
+	struct xfs_scrub_btree		*bs,
+	int				level,
+	int				direction,
+	union xfs_btree_ptr		*sibling)
+{
+	struct xfs_btree_cur		*cur = bs->cur;
+	struct xfs_btree_block		*pblock;
+	struct xfs_buf			*pbp;
+	struct xfs_btree_cur		*ncur = NULL;
+	union xfs_btree_ptr		*pp;
+	int				success;
+	int				error;
+
+	error = xfs_btree_dup_cursor(cur, &ncur);
+	if (!xfs_scrub_btree_process_error(bs->sc, cur, level + 1, &error) ||
+	    !ncur)
+		return error;
+
+	/*
+	 * If the pointer is null, we shouldn't be able to move the upper
+	 * level pointer anywhere.
+	 */
+	if (xfs_btree_ptr_is_null(cur, sibling)) {
+		if (direction > 0)
+			error = xfs_btree_increment(ncur, level + 1, &success);
+		else
+			error = xfs_btree_decrement(ncur, level + 1, &success);
+		if (error == 0 && success)
+			xfs_scrub_btree_set_corrupt(bs->sc, cur, level);
+		error = 0;
+		goto out;
+	}
+
+	/* Increment upper level pointer. */
+	if (direction > 0)
+		error = xfs_btree_increment(ncur, level + 1, &success);
+	else
+		error = xfs_btree_decrement(ncur, level + 1, &success);
+	if (!xfs_scrub_btree_process_error(bs->sc, cur, level + 1, &error))
+		goto out;
+	if (!success) {
+		xfs_scrub_btree_set_corrupt(bs->sc, cur, level + 1);
+		goto out;
+	}
+
+	/* Compare upper level pointer to sibling pointer. */
+	pblock = xfs_btree_get_block(ncur, level + 1, &pbp);
+	pp = xfs_btree_ptr_addr(ncur, ncur->bc_ptrs[level + 1], pblock);
+	if (!xfs_scrub_btree_ptr_ok(bs, level + 1, pp))
+		goto out;
+
+	if (xfs_btree_diff_two_ptrs(cur, pp, sibling))
+		xfs_scrub_btree_set_corrupt(bs->sc, cur, level);
+out:
+	xfs_btree_del_cursor(ncur, XFS_BTREE_ERROR);
+	return error;
+}
+
+/* Check the siblings of a btree block. */
+STATIC int
+xfs_scrub_btree_block_check_siblings(
+	struct xfs_scrub_btree		*bs,
+	struct xfs_btree_block		*block)
+{
+	struct xfs_btree_cur		*cur = bs->cur;
+	union xfs_btree_ptr		leftsib;
+	union xfs_btree_ptr		rightsib;
+	int				level;
+	int				error = 0;
+
+	xfs_btree_get_sibling(cur, block, &leftsib, XFS_BB_LEFTSIB);
+	xfs_btree_get_sibling(cur, block, &rightsib, XFS_BB_RIGHTSIB);
+	level = xfs_btree_get_level(block);
+
+	/* Root block should never have siblings. */
+	if (level == cur->bc_nlevels - 1) {
+		if (!xfs_btree_ptr_is_null(cur, &leftsib) ||
+		    !xfs_btree_ptr_is_null(cur, &rightsib))
+			xfs_scrub_btree_set_corrupt(bs->sc, cur, level);
+		goto out;
+	}
+
+	/*
+	 * Does the left & right sibling pointers match the adjacent
+	 * parent level pointers?
+	 * (These function absorbs error codes for us.)
+	 */
+	error = xfs_scrub_btree_block_check_sibling(bs, level, -1, &leftsib);
+	if (error)
+		return error;
+	error = xfs_scrub_btree_block_check_sibling(bs, level, 1, &rightsib);
+	if (error)
+		return error;
+out:
+	return error;
+}
+
+/*
+ * Grab and scrub a btree block given a btree pointer.  Returns block
+ * and buffer pointers (if applicable) if they're ok to use.
+ */
+STATIC int
+xfs_scrub_btree_get_block(
+	struct xfs_scrub_btree		*bs,
+	int				level,
+	union xfs_btree_ptr		*pp,
+	struct xfs_btree_block		**pblock,
+	struct xfs_buf			**pbp)
+{
+	void				*failed_at;
+	int				error;
+
+	*pblock = NULL;
+	*pbp = NULL;
+
+	error = xfs_btree_lookup_get_block(bs->cur, level, pp, pblock);
+	if (!xfs_scrub_btree_process_error(bs->sc, bs->cur, level, &error) ||
+	    !*pblock)
+		return error;
+
+	xfs_btree_get_block(bs->cur, level, pbp);
+	if (bs->cur->bc_flags & XFS_BTREE_LONG_PTRS)
+		failed_at = __xfs_btree_check_lblock(bs->cur, *pblock,
+				level, *pbp);
+	else
+		failed_at = __xfs_btree_check_sblock(bs->cur, *pblock,
+				 level, *pbp);
+	if (failed_at) {
+		xfs_scrub_btree_set_corrupt(bs->sc, bs->cur, level);
+		return 0;
+	}
+
+	/*
+	 * Check the block's siblings; this function absorbs error codes
+	 * for us.
+	 */
+	return xfs_scrub_btree_block_check_siblings(bs, *pblock);
+}
+
+/*
+ * Check that the low and high keys of this block match the keys stored
+ * in the parent block.
+ */
+STATIC void
+xfs_scrub_btree_block_keys(
+	struct xfs_scrub_btree		*bs,
+	int				level,
+	struct xfs_btree_block		*block)
+{
+	union xfs_btree_key		block_keys;
+	struct xfs_btree_cur		*cur = bs->cur;
+	union xfs_btree_key		*high_bk;
+	union xfs_btree_key		*parent_keys;
+	union xfs_btree_key		*high_pk;
+	struct xfs_btree_block		*parent_block;
+	struct xfs_buf			*bp;
+
+	if (level >= cur->bc_nlevels - 1)
+		return;
+
+	/* Calculate the keys for this block. */
+	xfs_btree_get_keys(cur, block, &block_keys);
+
+	/* Obtain the parent's copy of the keys for this block. */
+	parent_block = xfs_btree_get_block(cur, level + 1, &bp);
+	parent_keys = xfs_btree_key_addr(cur, cur->bc_ptrs[level + 1],
+			parent_block);
+
+	if (cur->bc_ops->diff_two_keys(cur, &block_keys, parent_keys) != 0)
+		xfs_scrub_btree_set_corrupt(bs->sc, cur, 1);
+
+	if (!(cur->bc_flags & XFS_BTREE_OVERLAPPING))
+		return;
+
+	/* Get high keys */
+	high_bk = xfs_btree_high_key_from_key(cur, &block_keys);
+	high_pk = xfs_btree_high_key_addr(cur, cur->bc_ptrs[level + 1],
+			parent_block);
+
+	if (cur->bc_ops->diff_two_keys(cur, high_bk, high_pk) != 0)
+		xfs_scrub_btree_set_corrupt(bs->sc, cur, 1);
+}
+
+/*
+ * Visit all nodes and leaves of a btree.  Check that all pointers and
+ * records are in order, that the keys reflect the records, and use a callback
+ * so that the caller can verify individual records.
+ */
+int
+xfs_scrub_btree(
+	struct xfs_scrub_context	*sc,
+	struct xfs_btree_cur		*cur,
+	xfs_scrub_btree_rec_fn		scrub_fn,
+	struct xfs_owner_info		*oinfo,
+	void				*private)
+{
+	struct xfs_scrub_btree		bs = { NULL };
+	union xfs_btree_ptr		ptr;
+	union xfs_btree_ptr		*pp;
+	union xfs_btree_rec		*recp;
+	struct xfs_btree_block		*block;
+	int				level;
+	struct xfs_buf			*bp;
+	int				i;
+	int				error = 0;
+
+	/* Initialize scrub state */
+	bs.cur = cur;
+	bs.scrub_rec = scrub_fn;
+	bs.oinfo = oinfo;
+	bs.firstrec = true;
+	bs.private = private;
+	bs.sc = sc;
+	for (i = 0; i < XFS_BTREE_MAXLEVELS; i++)
+		bs.firstkey[i] = true;
+	INIT_LIST_HEAD(&bs.to_check);
+
+	/* Don't try to check a tree with a height we can't handle. */
+	if (cur->bc_nlevels > XFS_BTREE_MAXLEVELS) {
+		xfs_scrub_btree_set_corrupt(sc, cur, 0);
+		goto out;
+	}
+
+	/*
+	 * Load the root of the btree.  The helper function absorbs
+	 * error codes for us.
+	 */
+	level = cur->bc_nlevels - 1;
+	cur->bc_ops->init_ptr_from_cur(cur, &ptr);
+	if (!xfs_scrub_btree_ptr_ok(&bs, cur->bc_nlevels, &ptr))
+		goto out;
+	error = xfs_scrub_btree_get_block(&bs, level, &ptr, &block, &bp);
+	if (error || !block)
+		goto out;
+
+	cur->bc_ptrs[level] = 1;
+
+	while (level < cur->bc_nlevels) {
+		block = xfs_btree_get_block(cur, level, &bp);
+
+		if (level == 0) {
+			/* End of leaf, pop back towards the root. */
+			if (cur->bc_ptrs[level] >
+			    be16_to_cpu(block->bb_numrecs)) {
+				xfs_scrub_btree_block_keys(&bs, level, block);
+				if (level < cur->bc_nlevels - 1)
+					cur->bc_ptrs[level + 1]++;
+				level++;
+				continue;
+			}
+
+			/* Records in order for scrub? */
+			xfs_scrub_btree_rec(&bs);
+
+			/* Call out to the record checker. */
+			recp = xfs_btree_rec_addr(cur, cur->bc_ptrs[0], block);
+			error = bs.scrub_rec(&bs, recp);
+			if (error)
+				break;
+			if (xfs_scrub_should_terminate(sc, &error) ||
+			    (sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT))
+				break;
+
+			cur->bc_ptrs[level]++;
+			continue;
+		}
+
+		/* End of node, pop back towards the root. */
+		if (cur->bc_ptrs[level] > be16_to_cpu(block->bb_numrecs)) {
+			xfs_scrub_btree_block_keys(&bs, level, block);
+			if (level < cur->bc_nlevels - 1)
+				cur->bc_ptrs[level + 1]++;
+			level++;
+			continue;
+		}
+
+		/* Keys in order for scrub? */
+		xfs_scrub_btree_key(&bs, level);
+
+		/* Drill another level deeper. */
+		pp = xfs_btree_ptr_addr(cur, cur->bc_ptrs[level], block);
+		if (!xfs_scrub_btree_ptr_ok(&bs, level, pp)) {
+			cur->bc_ptrs[level]++;
+			continue;
+		}
+		level--;
+		error = xfs_scrub_btree_get_block(&bs, level, pp, &block, &bp);
+		if (error || !block)
+			goto out;
+
+		cur->bc_ptrs[level] = 1;
+	}
+
+out:
+	return error;
+}