[PATCH v2 2/5] btrfs: tree-checker: Enhance btrfs_check_node output

[Qu Wenruo <quwenruo.btrfs@gmx.com>]

Use inline function to replace macro since we don't need
stringification.
(Macro still exist until all caller get updated)

And add more info about the error.

For nr_items error, report if it's too large or too small, and output
valid value range.

For blk pointer, added a new alignment checker.

For key order, also output the next key to make the problem more
obvious.

Signed-off-by: Qu Wenruo <quwenruo.btrfs@gmx.com>
---
 fs/btrfs/tree-checker.c | 65 ++++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 61 insertions(+), 4 deletions(-)

diff --git a/fs/btrfs/tree-checker.c b/fs/btrfs/tree-checker.c
index 301243a69dea..a51f2503acc4 100644
--- a/fs/btrfs/tree-checker.c
+++ b/fs/btrfs/tree-checker.c
@@ -37,6 +37,48 @@
 		   btrfs_header_level(eb) == 0 ? "leaf" : "node",	\
 		   reason, btrfs_header_bytenr(eb), root->objectid, slot)
 
+/*
+ * Error message should follow the format below:
+ * corrupt <type>: <identifier>, <reason>[, <bad_value>]
+ *
+ * @type:	Either leaf or node
+ * @identifier:	The necessary info to locate the leaf/node.
+ * 		It's recommened to decode key.objecitd/offset if it's
+ * 		meaningful.
+ * @reason:	What's wrong
+ * @bad_value:	Optional, it's recommened to output bad value and its
+ *		expected value (range).
+ *
+ * Since comma is used to separate the components, only SPACE is allowed
+ * inside each component.
+ */
+
+/*
+ * Append the generic "corrupt leaf/node root=%llu block=%llu slot=%d: " to
+ * @fmt.
+ * Allowing user to customize their output.
+ */
+__printf(4, 5)
+static void generic_err(const struct btrfs_root *root,
+			const struct extent_buffer *eb,
+			int slot, const char *fmt, ...)
+{
+	struct va_format vaf;
+	va_list args;
+
+	va_start(args, fmt);
+
+	vaf.fmt = fmt;
+	vaf.va = &args;
+
+	btrfs_crit(root->fs_info,
+		"corrupt %s: root=%llu block=%llu slot=%d, %pV",
+		btrfs_header_level(eb) == 0 ? "leaf" : "node",
+		root->objectid, btrfs_header_bytenr(eb), slot,
+		&vaf);
+	va_end(args);
+}
+
 static int check_extent_data_item(struct btrfs_root *root,
 				  struct extent_buffer *leaf,
 				  struct btrfs_key *key, int slot)
@@ -282,8 +324,10 @@ int btrfs_check_node(struct btrfs_root *root, struct extent_buffer *node)
 
 	if (nr == 0 || nr > BTRFS_NODEPTRS_PER_BLOCK(root->fs_info)) {
 		btrfs_crit(root->fs_info,
-			   "corrupt node: block %llu root %llu nritems %lu",
-			   node->start, root->objectid, nr);
+			"corrupt node: root=%llu block=%llu, nritems too %s, have %lu expect range [1,%u]",
+			   root->objectid, node->start,
+			   nr == 0 ? "small" : "large", nr,
+			   BTRFS_NODEPTRS_PER_BLOCK(root->fs_info));
 		return -EIO;
 	}
 
@@ -293,13 +337,26 @@ int btrfs_check_node(struct btrfs_root *root, struct extent_buffer *node)
 		btrfs_node_key_to_cpu(node, &next_key, slot + 1);
 
 		if (!bytenr) {
-			CORRUPT("invalid item slot", node, root, slot);
+			generic_err(root, node, slot,
+				"invalid node pointer, have %llu shouldn't be 0",
+				bytenr);
 			ret = -EIO;
 			goto out;
 		}
+		if (!IS_ALIGNED(bytenr, root->fs_info->sectorsize)) {
+			generic_err(root, node, slot,
+				"unaligned pointer, have %llu should be aligned to %u",
+				bytenr, root->fs_info->sectorsize);
+			ret = -EUCLEAN;
+			goto out;
+		}
 
 		if (btrfs_comp_cpu_keys(&key, &next_key) >= 0) {
-			CORRUPT("bad key order", node, root, slot);
+			generic_err(root, node, slot,
+				"bad key order, current key (%llu %u %llu) next key (%llu %u %llu)",
+				key.objectid, key.type, key.offset,
+				next_key.objectid, next_key.type,
+				next_key.offset);
 			ret = -EIO;
 			goto out;
 		}
-- 
2.14.2