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222 lines
5.8 KiB
C
222 lines
5.8 KiB
C
/* vi: set sw=4 ts=4: */
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/*
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* res_gdt.c --- reserve blocks for growing the group descriptor table
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* during online resizing.
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*
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* Copyright (C) 2002 Andreas Dilger
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*
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* %Begin-Header%
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* This file may be redistributed under the terms of the GNU Public
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* License.
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* %End-Header%
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*/
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#include <stdio.h>
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#include <string.h>
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#include <time.h>
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#include "ext2_fs.h"
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#include "ext2fs.h"
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/*
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* Iterate through the groups which hold BACKUP superblock/GDT copies in an
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* ext3 filesystem. The counters should be initialized to 1, 5, and 7 before
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* calling this for the first time. In a sparse filesystem it will be the
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* sequence of powers of 3, 5, and 7: 1, 3, 5, 7, 9, 25, 27, 49, 81, ...
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* For a non-sparse filesystem it will be every group: 1, 2, 3, 4, ...
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*/
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static unsigned int list_backups(ext2_filsys fs, unsigned int *three,
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unsigned int *five, unsigned int *seven)
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{
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unsigned int *min = three;
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int mult = 3;
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unsigned int ret;
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if (!(fs->super->s_feature_ro_compat &
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EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER)) {
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ret = *min;
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*min += 1;
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return ret;
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}
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if (*five < *min) {
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min = five;
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mult = 5;
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}
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if (*seven < *min) {
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min = seven;
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mult = 7;
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}
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ret = *min;
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*min *= mult;
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return ret;
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}
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/*
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* This code assumes that the reserved blocks have already been marked in-use
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* during ext2fs_initialize(), so that they are not allocated for other
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* uses before we can add them to the resize inode (which has to come
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* after the creation of the inode table).
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*/
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errcode_t ext2fs_create_resize_inode(ext2_filsys fs)
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{
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errcode_t retval, retval2;
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struct ext2_super_block *sb;
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struct ext2_inode inode;
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__u32 *dindir_buf, *gdt_buf;
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int rsv_add;
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unsigned long long apb, inode_size;
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blk_t dindir_blk, rsv_off, gdt_off, gdt_blk;
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int dindir_dirty = 0, inode_dirty = 0;
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EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
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sb = fs->super;
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retval = ext2fs_get_mem(2 * fs->blocksize, (void *)&dindir_buf);
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if (retval)
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goto out_free;
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gdt_buf = (__u32 *)((char *)dindir_buf + fs->blocksize);
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retval = ext2fs_read_inode(fs, EXT2_RESIZE_INO, &inode);
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if (retval)
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goto out_free;
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/* Maximum possible file size (we donly use the dindirect blocks) */
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apb = EXT2_ADDR_PER_BLOCK(sb);
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rsv_add = fs->blocksize / 512;
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if ((dindir_blk = inode.i_block[EXT2_DIND_BLOCK])) {
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#ifdef RES_GDT_DEBUG
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printf("reading GDT dindir %u\n", dindir_blk);
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#endif
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retval = ext2fs_read_ind_block(fs, dindir_blk, dindir_buf);
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if (retval)
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goto out_inode;
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} else {
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blk_t goal = 3 + sb->s_reserved_gdt_blocks +
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fs->desc_blocks + fs->inode_blocks_per_group;
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retval = ext2fs_alloc_block(fs, goal, 0, &dindir_blk);
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if (retval)
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goto out_free;
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inode.i_mode = LINUX_S_IFREG | 0600;
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inode.i_links_count = 1;
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inode.i_block[EXT2_DIND_BLOCK] = dindir_blk;
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inode.i_blocks = rsv_add;
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memset(dindir_buf, 0, fs->blocksize);
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#ifdef RES_GDT_DEBUG
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printf("allocated GDT dindir %u\n", dindir_blk);
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#endif
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dindir_dirty = inode_dirty = 1;
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inode_size = apb*apb + apb + EXT2_NDIR_BLOCKS;
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inode_size *= fs->blocksize;
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inode.i_size = inode_size & 0xFFFFFFFF;
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inode.i_size_high = (inode_size >> 32) & 0xFFFFFFFF;
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if(inode.i_size_high) {
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sb->s_feature_ro_compat |=
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EXT2_FEATURE_RO_COMPAT_LARGE_FILE;
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}
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inode.i_ctime = time(0);
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}
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for (rsv_off = 0, gdt_off = fs->desc_blocks,
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gdt_blk = sb->s_first_data_block + 1 + fs->desc_blocks;
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rsv_off < sb->s_reserved_gdt_blocks;
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rsv_off++, gdt_off++, gdt_blk++) {
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unsigned int three = 1, five = 5, seven = 7;
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unsigned int grp, last = 0;
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int gdt_dirty = 0;
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gdt_off %= apb;
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if (!dindir_buf[gdt_off]) {
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/* FIXME XXX XXX
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blk_t new_blk;
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retval = ext2fs_new_block(fs, gdt_blk, 0, &new_blk);
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if (retval)
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goto out_free;
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if (new_blk != gdt_blk) {
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// XXX free block
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retval = -1; // XXX
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}
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*/
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gdt_dirty = dindir_dirty = inode_dirty = 1;
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memset(gdt_buf, 0, fs->blocksize);
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dindir_buf[gdt_off] = gdt_blk;
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inode.i_blocks += rsv_add;
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#ifdef RES_GDT_DEBUG
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printf("added primary GDT block %u at %u[%u]\n",
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gdt_blk, dindir_blk, gdt_off);
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#endif
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} else if (dindir_buf[gdt_off] == gdt_blk) {
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#ifdef RES_GDT_DEBUG
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printf("reading primary GDT block %u\n", gdt_blk);
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#endif
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retval = ext2fs_read_ind_block(fs, gdt_blk, gdt_buf);
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if (retval)
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goto out_dindir;
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} else {
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#ifdef RES_GDT_DEBUG
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printf("bad primary GDT %u != %u at %u[%u]\n",
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dindir_buf[gdt_off], gdt_blk,dindir_blk,gdt_off);
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#endif
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retval = EXT2_ET_RESIZE_INODE_CORRUPT;
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goto out_dindir;
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}
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while ((grp = list_backups(fs, &three, &five, &seven)) <
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fs->group_desc_count) {
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blk_t expect = gdt_blk + grp * sb->s_blocks_per_group;
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if (!gdt_buf[last]) {
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#ifdef RES_GDT_DEBUG
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printf("added backup GDT %u grp %u@%u[%u]\n",
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expect, grp, gdt_blk, last);
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#endif
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gdt_buf[last] = expect;
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inode.i_blocks += rsv_add;
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gdt_dirty = inode_dirty = 1;
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} else if (gdt_buf[last] != expect) {
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#ifdef RES_GDT_DEBUG
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printf("bad backup GDT %u != %u at %u[%u]\n",
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gdt_buf[last], expect, gdt_blk, last);
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#endif
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retval = EXT2_ET_RESIZE_INODE_CORRUPT;
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goto out_dindir;
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}
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last++;
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}
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if (gdt_dirty) {
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#ifdef RES_GDT_DEBUG
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printf("writing primary GDT block %u\n", gdt_blk);
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#endif
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retval = ext2fs_write_ind_block(fs, gdt_blk, gdt_buf);
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if (retval)
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goto out_dindir;
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}
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}
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out_dindir:
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if (dindir_dirty) {
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retval2 = ext2fs_write_ind_block(fs, dindir_blk, dindir_buf);
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if (!retval)
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retval = retval2;
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}
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out_inode:
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#ifdef RES_GDT_DEBUG
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printf("inode.i_blocks = %u, i_size = %u\n", inode.i_blocks,
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inode.i_size);
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#endif
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if (inode_dirty) {
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inode.i_atime = inode.i_mtime = time(0);
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retval2 = ext2fs_write_inode(fs, EXT2_RESIZE_INO, &inode);
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if (!retval)
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retval = retval2;
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}
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out_free:
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ext2fs_free_mem((void *)&dindir_buf);
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return retval;
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}
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