Add patch_io manager support to resize2fs and e2fsck

e2fsck/e2fsck.8.in

@@ -345,6 +345,12 @@ or
 .B \-p
 options.
 .TP
+.BI \-T " patch_file"
+Do not apply changes to the real filesystem; write updates into a sparse file
+named 'patch_file' to safely apply them later with e2patch(8) utility.
+You'll also be able to create a backup before applying patch and safely
+restore it in case of power outage or system crash.
+.TP
 .BI \-z " undo_file"
 Before overwriting a file system block, write the old contents of the block to
 an undo file.  This undo file can be used with e2undo(8) to restore the old

e2fsck/e2fsck.h

@@ -391,6 +391,9 @@ struct e2fsck_struct {
 	 */
 	ext2fs_inode_bitmap inodes_to_rebuild;
 
+	/* Patch file */
+	char *patch_file;
+
 	/* Undo file */
 	char *undo_file;
 };

e2fsck/unix.c

@@ -76,7 +76,7 @@ static void usage(e2fsck_t ctx)
 	fprintf(stderr,
 		_("Usage: %s [-panyrcdfktvDFV] [-b superblock] [-B blocksize]\n"
 		"\t\t[-l|-L bad_blocks_file] [-C fd] [-j external_journal]\n"
-		"\t\t[-E extended-options] [-z undo_file] device\n"),
+		"\t\t[-E extended-options] [-T patch_file] [-z undo_file] device\n"),
 		ctx->program_name);
 
 	fprintf(stderr, "%s", _("\nEmergency help:\n"
@@ -92,6 +92,7 @@ static void usage(e2fsck_t ctx)
 		" -j external_journal  Set location of the external journal\n"
 		" -l bad_blocks_file   Add to badblocks list\n"
 		" -L bad_blocks_file   Set badblocks list\n"
+		" -T patch_file        Create a patch file instead of applying changes to real FS\n"
 		" -z undo_file         Create an undo file\n"
 		));
 
@@ -804,7 +805,7 @@ static errcode_t PRS(int argc, char *argv[], e2fsck_t *ret_ctx)
 
 	phys_mem_kb = get_memory_size() / 1024;
 	ctx->readahead_kb = ~0ULL;
-	while ((c = getopt(argc, argv, "panyrcC:B:dE:fvtFVM:b:I:j:P:l:L:N:SsDkz:")) != EOF)
+	while ((c = getopt(argc, argv, "panyrcC:B:dE:fvtFVM:b:I:j:P:l:L:N:SsDkT:z:")) != EOF)
 		switch (c) {
 		case 'C':
 			ctx->progress = e2fsck_update_progress;
@@ -936,6 +937,9 @@ static errcode_t PRS(int argc, char *argv[], e2fsck_t *ret_ctx)
 		case 'k':
 			keep_bad_blocks++;
 			break;
+		case 'T':
+			ctx->patch_file = optarg;
+			break;
 		case 'z':
 			ctx->undo_file = optarg;
 			break;
@@ -1233,6 +1237,19 @@ check_error:
 	return retval;
 }
 
+static int e2fsck_setup_patch(e2fsck_t ctx, io_manager *io_ptr)
+{
+	set_patch_io_backing_manager(*io_ptr);
+	set_patch_io_patch_file(ctx->patch_file);
+	*io_ptr = patch_io_manager;
+	printf(_("To make backup before applying changes run:\n"
+		"  e2patch backup %s %s %s.backup\n"
+		"Then, to apply the operation to the real filesystem run:\n"
+		"  e2patch apply %s %s\n"),
+		ctx->device_name, ctx->patch_file, ctx->patch_file, ctx->device_name, ctx->patch_file);
+	return 0;
+}
+
 static int e2fsck_setup_tdb(e2fsck_t ctx, io_manager *io_ptr)
 {
 	errcode_t retval = ENOMEM;
@@ -1430,7 +1447,11 @@ restart:
 			flags &= ~EXT2_FLAG_EXCLUSIVE;
 	}
 
-	if (ctx->undo_file) {
+	if (ctx->patch_file) {
+		retval = e2fsck_setup_patch(ctx, &io_ptr);
+		if (retval)
+			exit(FSCK_ERROR);
+	} else if (ctx->undo_file) {
 		retval = e2fsck_setup_tdb(ctx, &io_ptr);
 		if (retval)
 			exit(FSCK_ERROR);

resize/main.c

@@ -47,7 +47,7 @@ static char *device_name, *io_options;
 static void usage (char *prog)
 {
 	fprintf (stderr, _("Usage: %s [-d debug_flags] [-f] [-F] [-M] [-P] "
-			   "[-p] device [-b|-s|new_size] [-z undo_file]\n\n"),
+			   "[-p] device [-b|-s|new_size] [-T patch_file] [-z undo_file]\n\n"),
 		 prog);
 
 	exit (1);
@@ -167,6 +167,20 @@ static void bigalloc_check(ext2_filsys fs, int force)
 	}
 }
 
+static int resize2fs_setup_patch(const char *device, char *patch_file,
+			       io_manager *io_ptr)
+{
+	set_patch_io_backing_manager(*io_ptr);
+	set_patch_io_patch_file(patch_file);
+	*io_ptr = patch_io_manager;
+	printf(_("To make backup before applying changes run:\n"
+		"  e2patch backup %s %s %s.backup\n"
+		"Then, to apply the operation to the real filesystem run:\n"
+		"  e2patch apply %s %s\n"),
+		device, patch_file, patch_file, device, patch_file);
+	return 0;
+}
+
 static int resize2fs_setup_tdb(const char *device, char *undo_file,
 			       io_manager *io_ptr)
 {
@@ -267,7 +281,7 @@ int main (int argc, char ** argv)
 	unsigned int	blocksize;
 	long		sysval;
 	int		len, mount_flags;
-	char		*mtpt, *undo_file = NULL;
+	char		*mtpt, *undo_file = NULL, *patch_file = NULL;
 
 #ifdef ENABLE_NLS
 	setlocale(LC_MESSAGES, "");
@@ -284,7 +298,7 @@ int main (int argc, char ** argv)
 	if (argc && *argv)
 		program_name = *argv;
 
-	while ((c = getopt(argc, argv, "d:fFhMPpS:bsz:")) != EOF) {
+	while ((c = getopt(argc, argv, "d:fFhMPpS:bsT:z:")) != EOF) {
 		switch (c) {
 		case 'h':
 			usage(program_name);
@@ -316,6 +330,9 @@ int main (int argc, char ** argv)
 		case 's':
 			flags |= RESIZE_DISABLE_64BIT;
 			break;
+		case 'T':
+			patch_file = optarg;
+			break;
 		case 'z':
 			undo_file = optarg;
 			break;
@@ -402,7 +419,11 @@ int main (int argc, char ** argv)
 		io_flags = EXT2_FLAG_RW | EXT2_FLAG_EXCLUSIVE;
 
 	io_flags |= EXT2_FLAG_64BITS;
-	if (undo_file) {
+	if (patch_file) {
+		retval = resize2fs_setup_patch(device_name, patch_file, &io_ptr);
+		if (retval)
+			exit(1);
+	} else if (undo_file) {
 		retval = resize2fs_setup_tdb(device_name, undo_file, &io_ptr);
 		if (retval)
 			exit(1);

resize/resize2fs.8.in

@@ -159,6 +159,12 @@ program will heuristically determine the RAID stride that was specified
 when the filesystem was created.  This option allows the user to
 explicitly specify a RAID stride setting to be used by resize2fs instead.
 .TP
+.BI \-T " patch_file"
+Do not apply changes to the real filesystem; write updates into a sparse file
+named 'patch_file' to safely apply them later with e2patch(8) utility.
+You'll also be able to create a backup before applying patch and safely
+restore it in case of power outage or system crash.
+.TP
 .BI \-z " undo_file"
 Before overwriting a file system block, write the old contents of the block to
 an undo file.  This undo file can be used with e2undo(8) to restore the old