Add support for on-line resizing to resize2fs

If the filesystem is mounted, attempt to use the on-line resizing
ioctls to resize the filesystem.

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

1 files changed, 141 insertions, 0 deletions

diff --git a/resize/online.c b/resize/online.c
new file mode 100644
index 00000000..45262b12
--- /dev/null
+++ b/resize/online.c
@@ -0,0 +1,141 @@
+/*
+ * online.c --- Do on-line resizing of the ext3 filesystem
+ *
+ * Copyright (C) 2006 by Theodore Ts'o 
+ * 
+ * %Begin-Header%
+ * This file may be redistributed under the terms of the GNU Public
+ * License.
+ * %End-Header%
+ */
+
+#include "resize2fs.h"
+#ifdef HAVE_SYS_IOCTL_H
+#include <sys/ioctl.h>
+#endif
+#include <sys/stat.h>
+#include <fcntl.h>
+
+extern char *program_name;
+
+errcode_t online_resize_fs(ext2_filsys fs, const char *mtpt, 
+			   blk_t *new_size, int flags)
+{
+	struct ext2_new_group_input input;
+	struct ext2_super_block *sb = fs->super;
+	ext2_filsys 		new_fs;
+	errcode_t 		retval;
+	dgrp_t			i;
+	blk_t			size;
+	int			fd, r_frac, overhead;
+
+	printf(_("Filesystem at %s is mounted on %s; "
+		 "on-line resizing required\n"), fs->device_name, mtpt);
+
+	if (*new_size < sb->s_blocks_count) {
+		printf(_("On-line shrinking from %u to %u not supported.\n"),
+		       sb->s_blocks_count, *new_size);
+		exit(1);
+	}
+
+	fd = open(mtpt, O_RDONLY);
+	if (fd < 0) {
+		com_err(program_name, errno, 
+			_("while trying to open mountpoint %s"), mtpt);
+		exit(1);
+	}
+
+	size=sb->s_blocks_count;
+	if (ioctl(fd, EXT2_IOC_GROUP_EXTEND, &size)) {
+		if (errno == EPERM)
+			com_err(program_name, 0, 
+				_("Permission denied to resize filesystem"));
+		else if (errno == ENOTTY)
+			com_err(program_name, 0, 
+			_("Filesystem does not support online resizing"));
+		else 
+			com_err(program_name, errno, 
+			_("While checking for on-line resizing support"));
+		exit(1);
+	}
+
+	r_frac = ((100 * sb->s_r_blocks_count) + sb->s_blocks_count-1) /
+		sb->s_blocks_count;
+
+	retval = ext2fs_read_bitmaps(fs);
+	if (retval)
+		return retval;
+
+	retval = ext2fs_dup_handle(fs, &new_fs);
+	if (retval)
+		return retval;
+
+	retval = adjust_fs_info(new_fs, fs, *new_size);
+	if (retval)
+		return retval;
+
+	printf(_("Performing an on-line resize of %s to %d (%dk) blocks.\n"), 
+	       fs->device_name, *new_size, fs->blocksize / 1024);
+
+	size = fs->group_desc_count * sb->s_blocks_per_group + 
+		sb->s_first_data_block;
+	if (size > *new_size)
+		size = *new_size;
+
+	if (ioctl(fd, EXT2_IOC_GROUP_EXTEND, &size)) {
+		com_err(program_name, errno, 
+			_("While trying to extend the last group"));
+		exit(1);
+	}
+
+	for (i = fs->group_desc_count;
+	     i < new_fs->group_desc_count; i++) {
+
+		overhead = (int) (2 + new_fs->inode_blocks_per_group);
+
+		if (ext2fs_bg_has_super(new_fs, new_fs->group_desc_count - 1))
+			overhead += 1 + new_fs->desc_blocks + 
+				new_fs->super->s_reserved_gdt_blocks;
+
+		input.group = i;
+		input.block_bitmap = new_fs->group_desc[i].bg_block_bitmap;
+		input.inode_bitmap = new_fs->group_desc[i].bg_inode_bitmap;
+		input.inode_table = new_fs->group_desc[i].bg_inode_table;
+		input.blocks_count = sb->s_blocks_per_group;
+		if (i == new_fs->group_desc_count-1) {
+			input.blocks_count = new_fs->super->s_blocks_count -
+				sb->s_first_data_block - 
+				(i * sb->s_blocks_per_group);
+		}
+		input.reserved_blocks = input.blocks_count * r_frac / 100;
+
+#if 0
+		printf("new block bitmap is at 0x%04x\n", input.block_bitmap);
+		printf("new inode bitmap is at 0x%04x\n", input.inode_bitmap);
+		printf("new inode table is at 0x%04x-0x%04x\n", 
+		       input.inode_table,
+		       input.inode_table + new_fs->inode_blocks_per_group-1);
+		printf("new group has %d blocks\n", input.blocks_count);
+		printf("new group will reserve %d blocks\n", 
+		       input.reserved_blocks);
+		printf("new group has %d free blocks\n", 
+		       new_fs->group_desc[i].bg_free_blocks_count);
+		printf("new group has %d free inodes (%d blocks)\n",
+		       new_fs->group_desc[i].bg_free_inodes_count, 
+		       new_fs->inode_blocks_per_group);
+		printf("Adding group #%d\n", input.group);
+#endif
+
+		if (ioctl(fd, EXT2_IOC_GROUP_ADD, &input) < 0) {
+			com_err(program_name, errno, 
+				_("While trying to add group #%d"), 
+				input.group);
+			exit(1);
+		}
+	}
+
+	ext2fs_free(new_fs);
+	close(fd);
+
+	return 0;
+}