[Cluster-devel] [gfs2_edit PATCH] gfs2_edit: Add destroy_all_meta for fsck testing

[Bob Peterson]

Hi,

This patch adds a new option to gfs2_edit that destroys all the
metadata in a file system. Its sole purpose is for fsck testing
where multiple sets of metadata are restored to the same device,
to prevent accidental bleed-through from one to the next.
I deliberately left it off the tool "usage" so people aren't
tempted to try to misuse it (but that's open to negotiation).

Regards,

Bob Peterson
Red Hat File Systems
---
Signed-off-by: Bob Peterson <rpeterso at redhat.com>

diff --git a/gfs2/edit/hexedit.c b/gfs2/edit/hexedit.c
index 40a719e..adc6071 100644
--- a/gfs2/edit/hexedit.c
+++ b/gfs2/edit/hexedit.c
@@ -2291,6 +2291,8 @@ static void parameterpass1(int argc, char *argv[], int i)
 		details = 1;
 	else if (!strcasecmp(argv[i], "savemeta"))
 		termlines = 0;
+	else if (!strcasecmp(argv[i], "destroy_all_meta"))
+		termlines = 0;
 	else if (!strcasecmp(argv[i], "savemetaslow"))
 		termlines = 0;
 	else if (!strcasecmp(argv[i], "savergs"))
@@ -2486,6 +2488,8 @@ static void process_parameters(int argc, char *argv[], int pass)
 		else if (!strcasecmp(argv[i], "savemeta")) {
 			getgziplevel(argv, &i);
 			savemeta(argv[i+2], 0, gziplevel);
+		} else if (!strcasecmp(argv[i], "destroy_all_meta")) {
+			savemeta(argv[i+1], -1, gziplevel);
 		} else if (!strcasecmp(argv[i], "savemetaslow")) {
 			getgziplevel(argv, &i);
 			savemeta(argv[i+2], 1, gziplevel);
diff --git a/gfs2/edit/savemeta.c b/gfs2/edit/savemeta.c
index db9a947..0b60ba6 100644
--- a/gfs2/edit/savemeta.c
+++ b/gfs2/edit/savemeta.c
@@ -61,6 +61,7 @@ static uint64_t blks_saved;
 static uint64_t journal_blocks[MAX_JOURNALS_SAVED];
 static uint64_t gfs1_journal_size = 0; /* in blocks */
 static int journals_found = 0;
+static int destroy_all_meta = 0;
 int print_level = MSG_NOTICE;
 extern char *device;
 
@@ -432,6 +433,11 @@ static int save_block(int fd, struct metafd *mfd, uint64_t blk, uint64_t owner)
 		return 0; /* Not metadata, and not system file, so skip it */
 	}
 
+	if (destroy_all_meta) {
+		memset(savebh->b_data, 0, blklen);
+		bmodified(savebh);
+		goto out;
+	}
 	/* No need to save trailing zeroes */
 	for (; blklen > 0 && savebh->b_data[blklen - 1] == '\0'; blklen--);
 
@@ -459,6 +465,7 @@ static int save_block(int fd, struct metafd *mfd, uint64_t blk, uint64_t owner)
 
 	blks_saved++;
 	free(savedata);
+out:
 	brelse(savebh);
 	return blktype;
 }
@@ -795,7 +802,10 @@ void savemeta(char *out_fn, int saveoption, int gziplevel)
 
 	sbd.md.journals = 1;
 
-	mfd = savemetaopen(out_fn, gziplevel);
+	if (saveoption == -1)
+		destroy_all_meta = 1;
+	else
+		mfd = savemetaopen(out_fn, gziplevel);
 
 	blks_saved = 0;
 	if (sbd.gfs1)
@@ -820,10 +830,12 @@ void savemeta(char *out_fn, int saveoption, int gziplevel)
 		exit(1);
 
 	/* Write the savemeta file header */
-	err = save_header(&mfd, sbd.fssize * sbd.bsize);
-	if (err) {
-		perror("Failed to write metadata file header");
-		exit(1);
+	if (saveoption != -1) {
+		err = save_header(&mfd, sbd.fssize * sbd.bsize);
+		if (err) {
+			perror("Failed to write metadata file header");
+			exit(1);
+		}
 	}
 	/* Save off the superblock */
 	save_block(sbd.device_fd, &mfd, GFS2_SB_ADDR * GFS2_BASIC_BLOCK / sbd.bsize, 0);
@@ -879,7 +891,8 @@ void savemeta(char *out_fn, int saveoption, int gziplevel)
 	} else {
 		printf("(uncompressed).\n");
 	}
-	savemetaclose(&mfd);
+	if (saveoption != -1)
+		savemetaclose(&mfd);
 	close(sbd.device_fd);
 	destroy_per_node_lookup();
 	free(indirect);