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/* vi: set sw=4 ts=4: */
/*
* 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 Public
* License.
* %End-Header%
*/
#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 (!(fs->super->s_feature_ro_compat &
EXT2_FEATURE_RO_COMPAT_SPARSE_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;
int rsv_add;
unsigned long long apb, inode_size;
blk_t dindir_blk, rsv_off, gdt_off, gdt_blk;
int dindir_dirty = 0, inode_dirty = 0;
EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
sb = fs->super;
retval = ext2fs_get_mem(2 * fs->blocksize, (void *)&dindir_buf);
if (retval)
goto out_free;
gdt_buf = (__u32 *)((char *)dindir_buf + fs->blocksize);
retval = ext2fs_read_inode(fs, EXT2_RESIZE_INO, &inode);
if (retval)
goto out_free;
/* Maximum possible file size (we donly use the dindirect blocks) */
apb = EXT2_ADDR_PER_BLOCK(sb);
rsv_add = fs->blocksize / 512;
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 = 3 + sb->s_reserved_gdt_blocks +
fs->desc_blocks + 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;
inode.i_blocks = rsv_add;
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;
inode.i_size = inode_size & 0xFFFFFFFF;
inode.i_size_high = (inode_size >> 32) & 0xFFFFFFFF;
if (inode.i_size_high) {
sb->s_feature_ro_compat |=
EXT2_FEATURE_RO_COMPAT_LARGE_FILE;
}
inode.i_ctime = time(NULL);
}
for (rsv_off = 0, gdt_off = fs->desc_blocks,
gdt_blk = sb->s_first_data_block + 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;
inode.i_blocks += rsv_add;
#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;
inode.i_blocks += rsv_add;
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 = time(NULL);
retval2 = ext2fs_write_inode(fs, EXT2_RESIZE_INO, &inode);
if (!retval)
retval = retval2;
}
out_free:
ext2fs_free_mem((void *)&dindir_buf);
return retval;
}
|
