1/* vi: set sw=4 ts=4: */ 2/* 3 * res_gdt.c --- reserve blocks for growing the group descriptor table 4 * during online resizing. 5 * 6 * Copyright (C) 2002 Andreas Dilger 7 * 8 * %Begin-Header% 9 * This file may be redistributed under the terms of the GNU Public 10 * License. 11 * %End-Header% 12 */ 13 14#include <stdio.h> 15#include <string.h> 16#include <time.h> 17#include "ext2_fs.h" 18#include "ext2fs.h" 19 20/* 21 * Iterate through the groups which hold BACKUP superblock/GDT copies in an 22 * ext3 filesystem. The counters should be initialized to 1, 5, and 7 before 23 * calling this for the first time. In a sparse filesystem it will be the 24 * sequence of powers of 3, 5, and 7: 1, 3, 5, 7, 9, 25, 27, 49, 81, ... 25 * For a non-sparse filesystem it will be every group: 1, 2, 3, 4, ... 26 */ 27static unsigned int list_backups(ext2_filsys fs, unsigned int *three, 28 unsigned int *five, unsigned int *seven) 29{ 30 unsigned int *min = three; 31 int mult = 3; 32 unsigned int ret; 33 34 if (!(fs->super->s_feature_ro_compat & 35 EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER)) { 36 ret = *min; 37 *min += 1; 38 return ret; 39 } 40 41 if (*five < *min) { 42 min = five; 43 mult = 5; 44 } 45 if (*seven < *min) { 46 min = seven; 47 mult = 7; 48 } 49 50 ret = *min; 51 *min *= mult; 52 53 return ret; 54} 55 56/* 57 * This code assumes that the reserved blocks have already been marked in-use 58 * during ext2fs_initialize(), so that they are not allocated for other 59 * uses before we can add them to the resize inode (which has to come 60 * after the creation of the inode table). 61 */ 62errcode_t ext2fs_create_resize_inode(ext2_filsys fs) 63{ 64 errcode_t retval, retval2; 65 struct ext2_super_block *sb; 66 struct ext2_inode inode; 67 __u32 *dindir_buf, *gdt_buf; 68 int rsv_add; 69 unsigned long long apb, inode_size; 70 blk_t dindir_blk, rsv_off, gdt_off, gdt_blk; 71 int dindir_dirty = 0, inode_dirty = 0; 72 73 EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS); 74 75 sb = fs->super; 76 77 retval = ext2fs_get_mem(2 * fs->blocksize, (void *)&dindir_buf); 78 if (retval) 79 goto out_free; 80 gdt_buf = (__u32 *)((char *)dindir_buf + fs->blocksize); 81 82 retval = ext2fs_read_inode(fs, EXT2_RESIZE_INO, &inode); 83 if (retval) 84 goto out_free; 85 86 /* Maximum possible file size (we donly use the dindirect blocks) */ 87 apb = EXT2_ADDR_PER_BLOCK(sb); 88 rsv_add = fs->blocksize / 512; 89 if ((dindir_blk = inode.i_block[EXT2_DIND_BLOCK])) { 90#ifdef RES_GDT_DEBUG 91 printf("reading GDT dindir %u\n", dindir_blk); 92#endif 93 retval = ext2fs_read_ind_block(fs, dindir_blk, dindir_buf); 94 if (retval) 95 goto out_inode; 96 } else { 97 blk_t goal = 3 + sb->s_reserved_gdt_blocks + 98 fs->desc_blocks + fs->inode_blocks_per_group; 99 100 retval = ext2fs_alloc_block(fs, goal, 0, &dindir_blk); 101 if (retval) 102 goto out_free; 103 inode.i_mode = LINUX_S_IFREG | 0600; 104 inode.i_links_count = 1; 105 inode.i_block[EXT2_DIND_BLOCK] = dindir_blk; 106 inode.i_blocks = rsv_add; 107 memset(dindir_buf, 0, fs->blocksize); 108#ifdef RES_GDT_DEBUG 109 printf("allocated GDT dindir %u\n", dindir_blk); 110#endif 111 dindir_dirty = inode_dirty = 1; 112 inode_size = apb*apb + apb + EXT2_NDIR_BLOCKS; 113 inode_size *= fs->blocksize; 114 inode.i_size = inode_size & 0xFFFFFFFF; 115 inode.i_size_high = (inode_size >> 32) & 0xFFFFFFFF; 116 if(inode.i_size_high) { 117 sb->s_feature_ro_compat |= 118 EXT2_FEATURE_RO_COMPAT_LARGE_FILE; 119 } 120 inode.i_ctime = time(0); 121 } 122 123 for (rsv_off = 0, gdt_off = fs->desc_blocks, 124 gdt_blk = sb->s_first_data_block + 1 + fs->desc_blocks; 125 rsv_off < sb->s_reserved_gdt_blocks; 126 rsv_off++, gdt_off++, gdt_blk++) { 127 unsigned int three = 1, five = 5, seven = 7; 128 unsigned int grp, last = 0; 129 int gdt_dirty = 0; 130 131 gdt_off %= apb; 132 if (!dindir_buf[gdt_off]) { 133 gdt_dirty = dindir_dirty = inode_dirty = 1; 134 memset(gdt_buf, 0, fs->blocksize); 135 dindir_buf[gdt_off] = gdt_blk; 136 inode.i_blocks += rsv_add; 137#ifdef RES_GDT_DEBUG 138 printf("added primary GDT block %u at %u[%u]\n", 139 gdt_blk, dindir_blk, gdt_off); 140#endif 141 } else if (dindir_buf[gdt_off] == gdt_blk) { 142#ifdef RES_GDT_DEBUG 143 printf("reading primary GDT block %u\n", gdt_blk); 144#endif 145 retval = ext2fs_read_ind_block(fs, gdt_blk, gdt_buf); 146 if (retval) 147 goto out_dindir; 148 } else { 149#ifdef RES_GDT_DEBUG 150 printf("bad primary GDT %u != %u at %u[%u]\n", 151 dindir_buf[gdt_off], gdt_blk,dindir_blk,gdt_off); 152#endif 153 retval = EXT2_ET_RESIZE_INODE_CORRUPT; 154 goto out_dindir; 155 } 156 157 while ((grp = list_backups(fs, &three, &five, &seven)) < 158 fs->group_desc_count) { 159 blk_t expect = gdt_blk + grp * sb->s_blocks_per_group; 160 161 if (!gdt_buf[last]) { 162#ifdef RES_GDT_DEBUG 163 printf("added backup GDT %u grp %u@%u[%u]\n", 164 expect, grp, gdt_blk, last); 165#endif 166 gdt_buf[last] = expect; 167 inode.i_blocks += rsv_add; 168 gdt_dirty = inode_dirty = 1; 169 } else if (gdt_buf[last] != expect) { 170#ifdef RES_GDT_DEBUG 171 printf("bad backup GDT %u != %u at %u[%u]\n", 172 gdt_buf[last], expect, gdt_blk, last); 173#endif 174 retval = EXT2_ET_RESIZE_INODE_CORRUPT; 175 goto out_dindir; 176 } 177 last++; 178 } 179 if (gdt_dirty) { 180#ifdef RES_GDT_DEBUG 181 printf("writing primary GDT block %u\n", gdt_blk); 182#endif 183 retval = ext2fs_write_ind_block(fs, gdt_blk, gdt_buf); 184 if (retval) 185 goto out_dindir; 186 } 187 } 188 189out_dindir: 190 if (dindir_dirty) { 191 retval2 = ext2fs_write_ind_block(fs, dindir_blk, dindir_buf); 192 if (!retval) 193 retval = retval2; 194 } 195out_inode: 196#ifdef RES_GDT_DEBUG 197 printf("inode.i_blocks = %u, i_size = %u\n", inode.i_blocks, 198 inode.i_size); 199#endif 200 if (inode_dirty) { 201 inode.i_atime = inode.i_mtime = time(0); 202 retval2 = ext2fs_write_inode(fs, EXT2_RESIZE_INO, &inode); 203 if (!retval) 204 retval = retval2; 205 } 206out_free: 207 ext2fs_free_mem((void *)&dindir_buf); 208 return retval; 209} 210