e2fsprogs/lib/ext2fs/res_gdt.c - backupdr - Git at Google

 /*
  * res_gdt.c --- reserve blocks for growing the group descriptor table
  *               during online resizing.
  *
  * Copyright (C) 2002 Andreas Dilger
  *
  * %Begin-Header%
  * This file may be redistributed under the terms of the GNU Library
  * General Public License, version 2.
  * %End-Header%
  */

 #include "config.h"
 #include <stdio.h>
 #include <string.h>
 #include <time.h>
 #include "ext2_fs.h"
 #include "ext2fs.h"

 /*
  * Iterate through the groups which hold BACKUP superblock/GDT copies in an
  * ext3 filesystem.  The counters should be initialized to 1, 5, and 7 before
  * calling this for the first time.  In a sparse filesystem it will be the
  * sequence of powers of 3, 5, and 7: 1, 3, 5, 7, 9, 25, 27, 49, 81, ...
  * For a non-sparse filesystem it will be every group: 1, 2, 3, 4, ...
  */
 static unsigned int list_backups(ext2_filsys fs, unsigned int *three,
 				 unsigned int *five, unsigned int *seven)
 {
 	unsigned int *min = three;
 	int mult = 3;
 	unsigned int ret;

 	if (ext2fs_has_feature_sparse_super2(fs->super)) {
 		if (*min == 1) {
 			*min += 1;
 			if (fs->super->s_backup_bgs[0])
 				return fs->super->s_backup_bgs[0];
 		}
 		if (*min == 2) {
 			*min += 1;
 			if (fs->super->s_backup_bgs[1])
 				return fs->super->s_backup_bgs[1];
 		}
 		return fs->group_desc_count;
 	}
 	if (!ext2fs_has_feature_sparse_super(fs->super)) {
 		ret = *min;
 		*min += 1;
 		return ret;
 	}

 	if (*five < *min) {
 		min = five;
 		mult = 5;
 	}
 	if (*seven < *min) {
 		min = seven;
 		mult = 7;
 	}

 	ret = *min;
 	*min *= mult;

 	return ret;
 }

 /*
  * This code assumes that the reserved blocks have already been marked in-use
  * during ext2fs_initialize(), so that they are not allocated for other
  * uses before we can add them to the resize inode (which has to come
  * after the creation of the inode table).
  */
 errcode_t ext2fs_create_resize_inode(ext2_filsys fs)
 {
 	errcode_t		retval, retval2;
 	struct ext2_super_block	*sb;
 	struct ext2_inode	inode;
 	__u32			*dindir_buf, *gdt_buf;
 	unsigned long long	apb, inode_size;
 	/* FIXME-64 - can't deal with extents */
 	blk_t			dindir_blk, rsv_off, gdt_off, gdt_blk;
 	int			dindir_dirty = 0, inode_dirty = 0, sb_blk = 0;

 	EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);

 	sb = fs->super;

 	retval = ext2fs_get_array(2, fs->blocksize, &dindir_buf);
 	if (retval)
 		return retval;
 	gdt_buf = (__u32 *)((char *)dindir_buf + fs->blocksize);

 	retval = ext2fs_read_inode(fs, EXT2_RESIZE_INO, &inode);
 	if (retval)
 		goto out_free;

 	/*
 	 * File systems with a blocksize of 1024 and bigalloc have
 	 * sb->s_first_data_block of 0; yet the superblock is still at
 	 * block #1.  We compensate for it here.
 	 */
 	sb_blk = sb->s_first_data_block;
 	if (fs->blocksize == 1024 && sb_blk == 0)
 		sb_blk = 1;

 	/* Maximum possible file size (we donly use the dindirect blocks) */
 	apb = EXT2_ADDR_PER_BLOCK(sb);
 	if ((dindir_blk = inode.i_block[EXT2_DIND_BLOCK])) {
 #ifdef RES_GDT_DEBUG
 		printf("reading GDT dindir %u\n", dindir_blk);
 #endif
 		retval = ext2fs_read_ind_block(fs, dindir_blk, dindir_buf);
 		if (retval)
 			goto out_inode;
 	} else {
 		blk_t goal = sb_blk + fs->desc_blocks +
 			sb->s_reserved_gdt_blocks + 2 +
 			fs->inode_blocks_per_group;

 		retval = ext2fs_alloc_block(fs, goal, 0, &dindir_blk);
 		if (retval)
 			goto out_free;
 		inode.i_mode = LINUX_S_IFREG | 0600;
 		inode.i_links_count = 1;
 		inode.i_block[EXT2_DIND_BLOCK] = dindir_blk;
 		ext2fs_iblk_set(fs, &inode, 1);
 		memset(dindir_buf, 0, fs->blocksize);
 #ifdef RES_GDT_DEBUG
 		printf("allocated GDT dindir %u\n", dindir_blk);
 #endif
 		dindir_dirty = inode_dirty = 1;
 		inode_size = apb*apb + apb + EXT2_NDIR_BLOCKS;
 		inode_size *= fs->blocksize;
 		retval = ext2fs_inode_size_set(fs, &inode, inode_size);
 		if (retval)
 			goto out_free;
 		inode.i_ctime = fs->now ? fs->now : time(0);
 	}

 	for (rsv_off = 0, gdt_off = fs->desc_blocks,
 	     gdt_blk = sb_blk + 1 + fs->desc_blocks;
 	     rsv_off < sb->s_reserved_gdt_blocks;
 	     rsv_off++, gdt_off++, gdt_blk++) {
 		unsigned int three = 1, five = 5, seven = 7;
 		unsigned int grp, last = 0;
 		int gdt_dirty = 0;

 		gdt_off %= apb;
 		if (!dindir_buf[gdt_off]) {
 			/* FIXME XXX XXX
 			blk_t new_blk;

 			retval = ext2fs_new_block(fs, gdt_blk, 0, &new_blk);
 			if (retval)
 				goto out_free;
 			if (new_blk != gdt_blk) {
 				// XXX free block
 				retval = -1; // XXX
 			}
 			*/
 			gdt_dirty = dindir_dirty = inode_dirty = 1;
 			memset(gdt_buf, 0, fs->blocksize);
 			dindir_buf[gdt_off] = gdt_blk;
 			ext2fs_iblk_add_blocks(fs, &inode, 1);
 #ifdef RES_GDT_DEBUG
 			printf("added primary GDT block %u at %u[%u]\n",
 			       gdt_blk, dindir_blk, gdt_off);
 #endif
 		} else if (dindir_buf[gdt_off] == gdt_blk) {
 #ifdef RES_GDT_DEBUG
 			printf("reading primary GDT block %u\n", gdt_blk);
 #endif
 			retval = ext2fs_read_ind_block(fs, gdt_blk, gdt_buf);
 			if (retval)
 				goto out_dindir;
 		} else {
 #ifdef RES_GDT_DEBUG
 			printf("bad primary GDT %u != %u at %u[%u]\n",
 			       dindir_buf[gdt_off], gdt_blk,dindir_blk,gdt_off);
 #endif
 			retval = EXT2_ET_RESIZE_INODE_CORRUPT;
 			goto out_dindir;
 		}

 		while ((grp = list_backups(fs, &three, &five, &seven)) <
 		       fs->group_desc_count) {
 			blk_t expect = gdt_blk + grp * sb->s_blocks_per_group;

 			if (!gdt_buf[last]) {
 #ifdef RES_GDT_DEBUG
 				printf("added backup GDT %u grp %u@%u[%u]\n",
 				       expect, grp, gdt_blk, last);
 #endif
 				gdt_buf[last] = expect;
 				ext2fs_iblk_add_blocks(fs, &inode, 1);
 				gdt_dirty = inode_dirty = 1;
 			} else if (gdt_buf[last] != expect) {
 #ifdef RES_GDT_DEBUG
 				printf("bad backup GDT %u != %u at %u[%u]\n",
 				       gdt_buf[last], expect, gdt_blk, last);
 #endif
 				retval = EXT2_ET_RESIZE_INODE_CORRUPT;
 				goto out_dindir;
 			}
 			last++;
 		}
 		if (gdt_dirty) {
 #ifdef RES_GDT_DEBUG
 			printf("writing primary GDT block %u\n", gdt_blk);
 #endif
 			retval = ext2fs_write_ind_block(fs, gdt_blk, gdt_buf);
 			if (retval)
 				goto out_dindir;
 		}
 	}

 out_dindir:
 	if (dindir_dirty) {
 		retval2 = ext2fs_write_ind_block(fs, dindir_blk, dindir_buf);
 		if (!retval)
 			retval = retval2;
 	}
 out_inode:
 #ifdef RES_GDT_DEBUG
 	printf("inode.i_blocks = %u, i_size = %u\n", inode.i_blocks,
 	       inode.i_size);
 #endif
 	if (inode_dirty) {
 		inode.i_atime = inode.i_mtime = fs->now ? fs->now : time(0);
 		retval2 = ext2fs_write_new_inode(fs, EXT2_RESIZE_INO, &inode);
 		if (!retval)
 			retval = retval2;
 	}
 out_free:
 	ext2fs_free_mem(&dindir_buf);
 	return retval;
 }
	/*
	* res_gdt.c --- reserve blocks for growing the group descriptor table
	* during online resizing.
	*
	* Copyright (C) 2002 Andreas Dilger
	*
	* %Begin-Header%
	* This file may be redistributed under the terms of the GNU Library
	* General Public License, version 2.
	* %End-Header%
	*/

	#include "config.h"
	#include <stdio.h>
	#include <string.h>
	#include <time.h>
	#include "ext2_fs.h"
	#include "ext2fs.h"

	/*
	* Iterate through the groups which hold BACKUP superblock/GDT copies in an
	* ext3 filesystem. The counters should be initialized to 1, 5, and 7 before
	* calling this for the first time. In a sparse filesystem it will be the
	* sequence of powers of 3, 5, and 7: 1, 3, 5, 7, 9, 25, 27, 49, 81, ...
	* For a non-sparse filesystem it will be every group: 1, 2, 3, 4, ...
	*/
	static unsigned int list_backups(ext2_filsys fs, unsigned int *three,
	unsigned int five, unsigned int seven)
	{
	unsigned int *min = three;
	int mult = 3;
	unsigned int ret;

	if (ext2fs_has_feature_sparse_super2(fs->super)) {
	if (*min == 1) {
	*min += 1;
	if (fs->super->s_backup_bgs[0])
	return fs->super->s_backup_bgs[0];
	}
	if (*min == 2) {
	*min += 1;
	if (fs->super->s_backup_bgs[1])
	return fs->super->s_backup_bgs[1];
	}
	return fs->group_desc_count;
	}
	if (!ext2fs_has_feature_sparse_super(fs->super)) {
	ret = *min;
	*min += 1;
	return ret;
	}

	if (five < min) {
	min = five;
	mult = 5;
	}
	if (seven < min) {
	min = seven;
	mult = 7;
	}

	ret = *min;
	min = mult;

	return ret;
	}

	/*
	* This code assumes that the reserved blocks have already been marked in-use
	* during ext2fs_initialize(), so that they are not allocated for other
	* uses before we can add them to the resize inode (which has to come
	* after the creation of the inode table).
	*/
	errcode_t ext2fs_create_resize_inode(ext2_filsys fs)
	{
	errcode_t retval, retval2;
	struct ext2_super_block *sb;
	struct ext2_inode inode;
	__u32 dindir_buf, gdt_buf;
	unsigned long long apb, inode_size;
	/* FIXME-64 - can't deal with extents */
	blk_t dindir_blk, rsv_off, gdt_off, gdt_blk;
	int dindir_dirty = 0, inode_dirty = 0, sb_blk = 0;

	EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);

	sb = fs->super;

	retval = ext2fs_get_array(2, fs->blocksize, &dindir_buf);
	if (retval)
	return retval;
	gdt_buf = (__u32 )((char )dindir_buf + fs->blocksize);

	retval = ext2fs_read_inode(fs, EXT2_RESIZE_INO, &inode);
	if (retval)
	goto out_free;

	/*
	* File systems with a blocksize of 1024 and bigalloc have
	* sb->s_first_data_block of 0; yet the superblock is still at
	* block #1. We compensate for it here.
	*/
	sb_blk = sb->s_first_data_block;
	if (fs->blocksize == 1024 && sb_blk == 0)
	sb_blk = 1;

	/* Maximum possible file size (we donly use the dindirect blocks) */
	apb = EXT2_ADDR_PER_BLOCK(sb);
	if ((dindir_blk = inode.i_block[EXT2_DIND_BLOCK])) {
	#ifdef RES_GDT_DEBUG
	printf("reading GDT dindir %u\n", dindir_blk);
	#endif
	retval = ext2fs_read_ind_block(fs, dindir_blk, dindir_buf);
	if (retval)
	goto out_inode;
	} else {
	blk_t goal = sb_blk + fs->desc_blocks +
	sb->s_reserved_gdt_blocks + 2 +
	fs->inode_blocks_per_group;

	retval = ext2fs_alloc_block(fs, goal, 0, &dindir_blk);
	if (retval)
	goto out_free;
	inode.i_mode = LINUX_S_IFREG \| 0600;
	inode.i_links_count = 1;
	inode.i_block[EXT2_DIND_BLOCK] = dindir_blk;
	ext2fs_iblk_set(fs, &inode, 1);
	memset(dindir_buf, 0, fs->blocksize);
	#ifdef RES_GDT_DEBUG
	printf("allocated GDT dindir %u\n", dindir_blk);
	#endif
	dindir_dirty = inode_dirty = 1;
	inode_size = apb*apb + apb + EXT2_NDIR_BLOCKS;
	inode_size *= fs->blocksize;
	retval = ext2fs_inode_size_set(fs, &inode, inode_size);
	if (retval)
	goto out_free;
	inode.i_ctime = fs->now ? fs->now : time(0);
	}

	for (rsv_off = 0, gdt_off = fs->desc_blocks,
	gdt_blk = sb_blk + 1 + fs->desc_blocks;
	rsv_off < sb->s_reserved_gdt_blocks;
	rsv_off++, gdt_off++, gdt_blk++) {
	unsigned int three = 1, five = 5, seven = 7;
	unsigned int grp, last = 0;
	int gdt_dirty = 0;

	gdt_off %= apb;
	if (!dindir_buf[gdt_off]) {
	/* FIXME XXX XXX
	blk_t new_blk;

	retval = ext2fs_new_block(fs, gdt_blk, 0, &new_blk);
	if (retval)
	goto out_free;
	if (new_blk != gdt_blk) {
	// XXX free block
	retval = -1; // XXX
	}
	*/
	gdt_dirty = dindir_dirty = inode_dirty = 1;
	memset(gdt_buf, 0, fs->blocksize);
	dindir_buf[gdt_off] = gdt_blk;
	ext2fs_iblk_add_blocks(fs, &inode, 1);
	#ifdef RES_GDT_DEBUG
	printf("added primary GDT block %u at %u[%u]\n",
	gdt_blk, dindir_blk, gdt_off);
	#endif
	} else if (dindir_buf[gdt_off] == gdt_blk) {
	#ifdef RES_GDT_DEBUG
	printf("reading primary GDT block %u\n", gdt_blk);
	#endif
	retval = ext2fs_read_ind_block(fs, gdt_blk, gdt_buf);
	if (retval)
	goto out_dindir;
	} else {
	#ifdef RES_GDT_DEBUG
	printf("bad primary GDT %u != %u at %u[%u]\n",
	dindir_buf[gdt_off], gdt_blk,dindir_blk,gdt_off);
	#endif
	retval = EXT2_ET_RESIZE_INODE_CORRUPT;
	goto out_dindir;
	}

	while ((grp = list_backups(fs, &three, &five, &seven)) <
	fs->group_desc_count) {
	blk_t expect = gdt_blk + grp * sb->s_blocks_per_group;

	if (!gdt_buf[last]) {
	#ifdef RES_GDT_DEBUG
	printf("added backup GDT %u grp %u@%u[%u]\n",
	expect, grp, gdt_blk, last);
	#endif
	gdt_buf[last] = expect;
	ext2fs_iblk_add_blocks(fs, &inode, 1);
	gdt_dirty = inode_dirty = 1;
	} else if (gdt_buf[last] != expect) {
	#ifdef RES_GDT_DEBUG
	printf("bad backup GDT %u != %u at %u[%u]\n",
	gdt_buf[last], expect, gdt_blk, last);
	#endif
	retval = EXT2_ET_RESIZE_INODE_CORRUPT;
	goto out_dindir;
	}
	last++;
	}
	if (gdt_dirty) {
	#ifdef RES_GDT_DEBUG
	printf("writing primary GDT block %u\n", gdt_blk);
	#endif
	retval = ext2fs_write_ind_block(fs, gdt_blk, gdt_buf);
	if (retval)
	goto out_dindir;
	}
	}

	out_dindir:
	if (dindir_dirty) {
	retval2 = ext2fs_write_ind_block(fs, dindir_blk, dindir_buf);
	if (!retval)
	retval = retval2;
	}
	out_inode:
	#ifdef RES_GDT_DEBUG
	printf("inode.i_blocks = %u, i_size = %u\n", inode.i_blocks,
	inode.i_size);
	#endif
	if (inode_dirty) {
	inode.i_atime = inode.i_mtime = fs->now ? fs->now : time(0);
	retval2 = ext2fs_write_new_inode(fs, EXT2_RESIZE_INO, &inode);
	if (!retval)
	retval = retval2;
	}
	out_free:
	ext2fs_free_mem(&dindir_buf);
	return retval;
	}