debugfs: add -b and -e options to the inode_dump command

Teach the inode_dump command to dump out just the i_block array and
the extra space in the inode, as a convenience to someone
investigating a corrupted inode.

Signed-off-by: Theodore Ts'o <tytso@mit.edu>

3 files changed, 57 insertions, 11 deletions

diff --git a/debugfs/debugfs.8.in b/debugfs/debugfs.8.in
index 4b5f472e..358f802b 100644
--- a/debugfs/debugfs.8.in
+++ b/debugfs/debugfs.8.in
@@ -424,8 +424,16 @@ showing its tree structure.
 Print a listing of the inodes which use the one or more blocks specified
 on the command line.
 .TP
-.BI inode_dump " filespec"
+.BI inode_dump " [-b]|[-e] filespec"
 Print the contents of the inode data structure in hex and ASCII format.
+The
+.I \-b
+option causes the command to only dump the contents of the
+.B i_blocks
+array.  The
+.I \-e
+option causes the command to only dump the contents of the extra inode
+space, which is used to store in-line extended attributes.
 .TP
 .BI imap " filespec"
 Print the location of the inode data structure (in the inode table)
diff --git a/debugfs/debugfs.c b/debugfs/debugfs.c
index 905c8cdc..3780d394 100644
--- a/debugfs/debugfs.c
+++ b/debugfs/debugfs.c
@@ -2097,15 +2097,30 @@ void do_imap(int argc, char *argv[])
 
 void do_idump(int argc, char *argv[])
 {
+	struct ext2_inode_large *inode;
 	ext2_ino_t	ino;
 	unsigned char	*buf;
 	errcode_t	err;
-	int		isize;
+	unsigned int	isize, size, offset = 0;
+	int		c, mode = 0;
 
-	if (common_args_process(argc, argv, 2, 2, argv[0],
-				"<file>", 0))
+	reset_getopt();
+	while ((c = getopt (argc, argv, "be")) != EOF) {
+		if (mode || c == '?') {
+		print_usage:
+			com_err(argv[0], 0,
+				"Usage: inode_dump [-b]|[-e] <file>");
+			return;
+		}
+		mode = c;
+	}
+	if (optind != argc-1)
 		return;
-	ino = string_to_inode(argv[1]);
+
+	if (check_fs_open(argv[0]))
+		return;
+
+	ino = string_to_inode(argv[optind]);
 	if (!ino)
 		return;
 
@@ -2123,7 +2138,26 @@ void do_idump(int argc, char *argv[])
 		goto err;
 	}
 
-	do_byte_hexdump(stdout, buf, isize);
+	inode = (struct ext2_inode_large *) buf;
+	size = isize;
+	switch (mode) {
+	case 'b':
+		offset = ((char *) (&inode->i_block)) - ((char *) buf);
+		size = sizeof(inode->i_block);
+		break;
+	case 'e':
+		if (size <= EXT2_GOOD_OLD_INODE_SIZE) {
+		no_extra_space:
+			com_err(argv[0], 0, "No extra space in inode");
+			goto err;
+		}
+		offset = EXT2_GOOD_OLD_INODE_SIZE + inode->i_extra_isize;
+		if (offset > size)
+			goto err;
+		size -= offset;
+		break;
+	}
+	do_byte_hexdump(stdout, buf + offset, size);
 err:
 	ext2fs_free_mem(&buf);
 }
diff --git a/debugfs/zap.c b/debugfs/zap.c
index 0a1ae9b9..047e7856 100644
--- a/debugfs/zap.c
+++ b/debugfs/zap.c
@@ -234,29 +234,33 @@ errout:
 
 void do_byte_hexdump(FILE *fp, unsigned char *buf, size_t bufsize)
 {
-	size_t		i, j;
+	size_t		i, j, max;
 	int		suppress = -1;
 
 	for (i = 0; i < bufsize; i += 16) {
+		max = (bufsize - i > 16) ? 16 : bufsize - i;
 		if (suppress < 0) {
-			if (i && memcmp(buf + i, buf + i - 16, 16) == 0) {
+			if (i && memcmp(buf + i, buf + i - max, max) == 0) {
 				suppress = i;
 				fprintf(fp, "*\n");
 				continue;
 			}
 		} else {
-			if (memcmp(buf + i, buf + suppress, 16) == 0)
+			if (memcmp(buf + i, buf + suppress, max) == 0)
 				continue;
 			suppress = -1;
 		}
 		fprintf(fp, "%04o  ", (unsigned int)i);
 		for (j = 0; j < 16; j++) {
-			fprintf(fp, "%02x", buf[i+j]);
+			if (j < max)
+				fprintf(fp, "%02x", buf[i+j]);
+			else
+				fprintf(fp, "  ");
 			if ((j % 2) == 1)
 				fprintf(fp, " ");
 		}
 		fprintf(fp, " ");
-		for (j = 0; j < 16; j++)
+		for (j = 0; j < max; j++)
 			fprintf(fp, "%c", isprint(buf[i+j]) ? buf[i+j] : '.');
 		fprintf(fp, "\n");
 	}