Enhnaced the get backup superblock function so that it does

the right thing if the filesystem superblock is unavailable; 
it will search for the superblock by iterating over possible
blocksizes.

TODO

@@ -40,11 +40,6 @@ Add chmod command to debugfs.
 
 ------------------------------------------
 
-fix up get_backup_sb, so that it doesn't choose something bogus if
-fs->super->.... is ridiculous
-
-----------------------------------
-
 Maybe a bug in debugfs v.1.14:
 if a file has more than one hardlink, only the first filename is shown when
 using command
@@ -200,12 +195,6 @@ TODO list.
 check_if_mounted() should check to see if the file is in /proc/swaps,
 to avoid mkfs's or checking a active swap partition.
 
-----------------------------------------------------------------
-
-Add a check in configure.in on Linux systems making sure that
-/usr/include/linux and /usr/include/asm exist.  Otherwise you can have
-some very obscure errors!
-
 -----------------------------------------------------------------
 
 Debugfs's link command should set the file type information

e2fsck/ChangeLog

 2001-12-23  Theodore Tso  <tytso@valinux.com>
 
+	* util.c (get_backup_sb): This function now searches for the
+		backup superblock by iterating over possible blocksizes
+		instead of defaulting a guess of 8193 if the superblock
+		isn't available.
+
+	* message.c (expand_percent_expression), unix.c (main): Pass in
+		new parameters to get_backup_sb.  Also, in unix.c, use the
+		blocksize paramter in the e2fsck context structure instead
+		of using a static variable, since get_backup_sb wants to
+		be able to set the blocksize paramter.
+
+	* e2fsck.h: Update function prototype for get_backup_sb; also add
+		the blocksize parameter to the e2fsck context structure.
+
 	* Makefile.in, jfs_user.h: Move linux/jbd.h to
 		ext2fs/kernel-jbd.h, to avoid using the system header
 		file version of hbd.h when using diet glibc (since it

e2fsck/e2fsck.h

@@ -148,6 +148,7 @@ struct e2fsck_struct {
 	int	options;
 	blk_t	use_superblock;	/* sb requested by user */
 	blk_t	superblock;	/* sb used to open fs */
+	int	blocksize;	/* blocksize */
 	blk_t	num_blocks;	/* Total number of blocks */
 
 #ifdef HAVE_SETJMP_H
@@ -363,7 +364,8 @@ extern void e2fsck_write_inode(e2fsck_t ctx, unsigned long ino,
 #ifdef MTRACE
 extern void mtrace_print(char *mesg);
 #endif
-extern blk_t get_backup_sb(ext2_filsys fs);
+extern blk_t get_backup_sb(e2fsck_t ctx, ext2_filsys fs,
+			   const char *name, io_manager manager);
 extern int ext2_file_type(unsigned int mode);
 
 /* unix.c */

e2fsck/message.c

@@ -396,7 +396,7 @@ static _INLINE_ void expand_percent_expression(ext2_filsys fs, char ch,
 		print_pathname(fs, ctx->dir, ctx->ino);
 		break;
 	case 'S':
-		printf("%d", get_backup_sb(fs));
+		printf("%d", get_backup_sb(NULL, fs, NULL, NULL));
 		break;
 	case 's':
 		printf("%s", ctx->str ? ctx->str : "NULL");

e2fsck/unix.c

@@ -42,7 +42,6 @@ extern int optind;
 #include "../version.h"
 
 /* Command line options */
-static int blocksize = 0;
 static int swapfs = 0;
 static int normalize_swapfs = 0;
 static int cflag = 0;		/* check disk */
@@ -523,7 +522,7 @@ static errcode_t PRS(int argc, char *argv[], e2fsck_t *ret_ctx)
 			ctx->flags |= E2F_FLAG_SB_SPECIFIED;
 			break;
 		case 'B':
-			blocksize = atoi(optarg);
+			ctx->blocksize = atoi(optarg);
 			break;
 		case 'I':
 			ctx->inode_buffer_blocks = atoi(optarg);
@@ -731,9 +730,10 @@ restart:
 	if ((ctx->options & E2F_OPT_READONLY) == 0)
 		flags |= EXT2_FLAG_RW;
 
-	if (ctx->superblock && blocksize) {
+	if (ctx->superblock && ctx->blocksize) {
 		retval = ext2fs_open(ctx->filesystem_name, flags,
-				     ctx->superblock, blocksize, io_ptr, &fs);
+				     ctx->superblock, ctx->blocksize,
+				     io_ptr, &fs);
 	} else if (ctx->superblock) {
 		for (i=0; possible_block_sizes[i]; i++) {
 			retval = ext2fs_open(ctx->filesystem_name, flags,
@@ -754,7 +754,7 @@ restart:
 			printf(_("%s trying backup blocks...\n"),
 			       retval ? _("Couldn't find ext2 superblock,") :
 			       _("Group descriptors look bad..."));
-			ctx->superblock = get_backup_sb(fs);
+			get_backup_sb(ctx, fs, ctx->filesystem_name, io_ptr);
 			if (fs)
 				ext2fs_close(fs);
 			goto restart;

e2fsck/util.c

@@ -318,11 +318,72 @@ void mtrace_print(char *mesg)
 }
 #endif
 
-blk_t get_backup_sb(ext2_filsys fs)
+blk_t get_backup_sb(e2fsck_t ctx, ext2_filsys fs, const char *name,
+		   io_manager manager)
 {
-	if (!fs || !fs->super)
-		return 8193;
-	return fs->super->s_blocks_per_group + fs->super->s_first_data_block;
+	struct ext2_super_block *sb;
+	io_channel		io = NULL;
+	void			*buf;
+	int			blocksize;
+	blk_t			superblock, ret_sb = 8193;
+	
+	if (fs && fs->super) {
+		ret_sb = (fs->super->s_blocks_per_group +
+			  fs->super->s_first_data_block);
+		if (ctx) {
+			ctx->superblock = ret_sb;
+			ctx->blocksize = fs->blocksize;
+		}
+		return ret_sb;
+	}
+		
+	if (ctx) {
+		if (ctx->blocksize) {
+			ret_sb = ctx->blocksize * 8;
+			if (ctx->blocksize == 1024)
+				ret_sb++;
+			ctx->superblock = ret_sb;
+			return ret_sb;
+		}
+		ctx->superblock = ret_sb;
+		ctx->blocksize = 1024;
+	}
+
+	if (!name || !manager)
+		goto cleanup;
+
+	if (manager->open(name, 0, &io) != 0)
+		goto cleanup;
+
+	if (ext2fs_get_mem(SUPERBLOCK_SIZE, &buf))
+		goto cleanup;
+	sb = (struct ext2_super_block *) buf;
+
+	for (blocksize=1024; blocksize <= 8192 ; blocksize = blocksize*2) {
+		superblock = blocksize*8;
+		if (blocksize == 1024)
+			superblock++;
+		io_channel_set_blksize(io, blocksize);
+		if (io_channel_read_blk(io, superblock,
+					-SUPERBLOCK_SIZE, buf))
+			continue;
+#ifdef EXT2FS_ENABLE_SWAPFS
+		if (sb->s_magic == ext2fs_swab16(EXT2_SUPER_MAGIC))
+			ext2fs_swap_super(sb);
+#endif
+		if (sb->s_magic == EXT2_SUPER_MAGIC) {
+			ret_sb = ctx->superblock = superblock;
+			ctx->blocksize = blocksize;
+			break;
+		}
+	}
+
+cleanup:
+	if (io)
+		io_channel_close(io);
+	if (buf)
+		ext2fs_free_mem(&buf);
+	return (ret_sb);
 }
 
 /*