[Ocfs2-tools-devel] [PATCH 31/50] fsck.ocfs2: Add basic check for refcount block.

[Tao Ma]

Add basic check for refcount block.
They are RB_BLKNO, RB_GEN and RB_GEN_FIX.

Signed-off-by: Tao Ma <tao.ma at oracle.com>
---
 fsck.ocfs2/Makefile               |    1 +
 fsck.ocfs2/fsck.ocfs2.checks.8.in |   33 +++++++++++
 fsck.ocfs2/refcount.c             |  114 +++++++++++++++++++++++++++++++++++++
 3 files changed, 148 insertions(+), 0 deletions(-)
 create mode 100644 fsck.ocfs2/refcount.c

diff --git a/fsck.ocfs2/Makefile b/fsck.ocfs2/Makefile
index aa3e79e..63f86de 100644
--- a/fsck.ocfs2/Makefile
+++ b/fsck.ocfs2/Makefile
@@ -33,6 +33,7 @@ CFILES =	fsck.c		\
 		pass4.c 	\
 		pass5.c		\
 		problem.c 	\
+		refcount.c	\
 		slot_recovery.c \
 		strings.c 	\
 		util.c		\
diff --git a/fsck.ocfs2/fsck.ocfs2.checks.8.in b/fsck.ocfs2/fsck.ocfs2.checks.8.in
index f0b926c..02d60a6 100644
--- a/fsck.ocfs2/fsck.ocfs2.checks.8.in
+++ b/fsck.ocfs2/fsck.ocfs2.checks.8.in
@@ -566,6 +566,39 @@ found that a file has refcount loc while it does't have refcount flag set.
 
 Answering yes reset refcount loc to zero for the file.
 
+.SS "RB_BLKNO"
+refcount blocks contain a record of the disk block where they are located.
+An refcount block was found at a block that didn't match its recorded location.
+
+Answering yes will update the data structure in the refcount block to reflect
+its real location on disk.
+
+.SS "RB_GEN"
+Refcount blocks are created with a generation number to match the generation
+number of the volume at the time of creation.  An refcount block was found which
+contains a generation number that doesn't match.
+
+Answering yes implies that the generation number is correct and that the
+refcount block is from a previous file system.  The refcount block will be
+removed and the file that uses it will lose the refcounted information, but
+it may be regenerated later.
+
+.SS "RB_GEN_FIX"
+Refcount blocks are created with a generation number to match the generation
+number of the volume at the time of creation.  An refcount block was found which
+contains a generation number that doesn't match.
+
+Answering yes implies that the generation number in the refcount block is
+incorrect and that the refcount block is valid.  The generation number in the
+block is updated to match the generation number in the volume.
+
+.SS "RB_PARENT"
+refcount blocks contain a record of the parent this disk block belongs to.
+An refcount block was found storing a wrong parent location.
+
+Answering yes will update the data structure in the refcount block to reflect
+its parent's real location on disk.
+
 \" pass1b.c
 
 .SS "DUP_CLUSTERS_SYSFILE_CLONE"
diff --git a/fsck.ocfs2/refcount.c b/fsck.ocfs2/refcount.c
new file mode 100644
index 0000000..15687b4
--- /dev/null
+++ b/fsck.ocfs2/refcount.c
@@ -0,0 +1,114 @@
+/* -*- mode: c; c-basic-offset: 8; -*-
+ * vim: noexpandtab sw=8 ts=8 sts=0:
+ *
+ * refcount.c
+ *
+ * Copyright (C) 2009 Oracle.  All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will 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.
+ */
+
+#include <inttypes.h>
+#include "ocfs2/ocfs2.h"
+#include "problem.h"
+
+static const char *whoami = "refcount.c";
+
+static errcode_t check_rb(o2fsck_state *ost, uint64_t blkno,
+			  uint64_t root_blkno, int *is_valid)
+{
+	int changed = 0;
+	char *buf = NULL;
+	struct ocfs2_refcount_block *rb;
+	errcode_t ret;
+
+	/* XXX test that the block isn't already used */
+
+	/* we only consider a refcount block invalid if we were able to read
+	 * it and it didn't have a refcount block signature */
+	*is_valid = 1;
+
+	ret = ocfs2_malloc_block(ost->ost_fs->fs_io, &buf);
+	if (ret) {
+		com_err(whoami, ret, "while allocating a block-sized buffer "
+			"for a refcount block");
+		goto out;
+	}
+
+	ret = ocfs2_read_refcount_block_nocheck(ost->ost_fs, blkno, buf);
+	if (ret) {
+		com_err(whoami, ret, "reading refcount block at %"PRIu64" in "
+			"refcount tree %"PRIu64" for verification", blkno,
+			root_blkno);
+		if (ret == OCFS2_ET_BAD_EXTENT_BLOCK_MAGIC)
+			*is_valid = 0;
+		goto out;
+	}
+
+	rb = (struct ocfs2_refcount_block *)buf;
+
+	if (rb->rf_blkno != blkno &&
+	    prompt(ost, PY, PR_RB_BLKNO,
+		   "A refcount block at %"PRIu64" in refcount tree %"PRIu64" "
+		   "claims to be located at block %"PRIu64".  Update the "
+		   "refcount block's location?", blkno, root_blkno,
+		   (uint64_t)rb->rf_blkno)) {
+		rb->rf_blkno = blkno;
+		changed = 1;
+	}
+
+	if (rb->rf_fs_generation != ost->ost_fs_generation) {
+		if (prompt(ost, PY, PR_RB_GEN,
+			   "A refcount block at %"PRIu64" in refcount tree "
+			   "%"PRIu64" has a generation of %x which doesn't "
+			   "match the volume's generation of %x.  Consider "
+			   "this refcount block invalid?", blkno,
+			   root_blkno, rb->rf_fs_generation,
+			   ost->ost_fs_generation)) {
+
+			*is_valid = 0;
+			goto out;
+		}
+		if (prompt(ost, PY, PR_RB_GEN_FIX,
+			   "Update the refcount block's generation to match "
+			   "the volume?")) {
+			rb->rf_fs_generation = ost->ost_fs_generation;
+			changed = 1;
+		}
+	}
+
+	if (rb->rf_blkno != root_blkno &&
+	    rb->rf_parent != root_blkno &&
+	    prompt(ost, PY, PR_RB_PARENT,
+		   "A refcount block at %"PRIu64" in refcount tree %"PRIu64" "
+		   "claims to belong to tree %"PRIu64".  Update the "
+		   "parent's information?", blkno, root_blkno,
+		   (uint64_t)rb->rf_parent)) {
+		rb->rf_parent = root_blkno;
+		changed = 1;
+	}
+
+	/* XXX worry about suballoc node/bit */
+
+	if (changed) {
+		ret = ocfs2_write_refcount_block(ost->ost_fs, blkno, buf);
+		if (ret) {
+			com_err(whoami, ret, "while writing an updated "
+				"refcount block at %"PRIu64" for refcount "
+				"tree %"PRIu64,	blkno, root_blkno);
+			goto out;
+		}
+	}
+
+out:
+	if (buf)
+		ocfs2_free(&buf);
+	return 0;
+}
-- 
1.5.5