res_gdt.c revision 52bb0b050ab7001f92f8110c0167cedec53bdcb5
1/* 2 * res_gdt.c --- reserve blocks for growing the group descriptor table 3 * during online resizing. 4 * 5 * Copyright (C) 2002 Andreas Dilger 6 * 7 * %Begin-Header% 8 * This file may be redistributed under the terms of the GNU Public 9 * License. 10 * %End-Header% 11 */ 12 13#include <stdio.h> 14#include <string.h> 15#include <time.h> 16#include "ext2_fs.h" 17#include "ext2fs.h" 18 19/* 20 * Iterate through the groups which hold BACKUP superblock/GDT copies in an 21 * ext3 filesystem. The counters should be initialized to 1, 5, and 7 before 22 * calling this for the first time. In a sparse filesystem it will be the 23 * sequence of powers of 3, 5, and 7: 1, 3, 5, 7, 9, 25, 27, 49, 81, ... 24 * For a non-sparse filesystem it will be every group: 1, 2, 3, 4, ... 25 */ 26static unsigned int list_backups(ext2_filsys fs, unsigned int *three, 27 unsigned int *five, unsigned int *seven) 28{ 29 unsigned int *min = three; 30 int mult = 3; 31 unsigned int ret; 32 33 if (!(fs->super->s_feature_ro_compat & 34 EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER)) { 35 ret = *min; 36 *min += 1; 37 return ret; 38 } 39 40 if (*five < *min) { 41 min = five; 42 mult = 5; 43 } 44 if (*seven < *min) { 45 min = seven; 46 mult = 7; 47 } 48 49 ret = *min; 50 *min *= mult; 51 52 return ret; 53} 54 55/* 56 * This code assumes that the reserved blocks have already been marked in-use 57 * during ext2fs_initialize(), so that they are not allocated for other 58 * uses before we can add them to the resize inode (which has to come 59 * after the creation of the inode table). 60 */ 61errcode_t ext2fs_create_resize_inode(ext2_filsys fs) 62{ 63 errcode_t retval, retval2; 64 struct ext2_super_block *sb; 65 struct ext2_inode inode; 66 __u32 *dindir_buf, *gdt_buf; 67 int rsv_add; 68 unsigned long long apb, inode_size; 69 blk_t dindir_blk, rsv_off, gdt_off, gdt_blk; 70 int dindir_dirty = 0, inode_dirty = 0; 71 72 EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS); 73 74 sb = fs->super; 75 76 retval = ext2fs_get_array(2, fs->blocksize, &dindir_buf); 77 if (retval) 78 goto out_free; 79 gdt_buf = (__u32 *)((char *)dindir_buf + fs->blocksize); 80 81 retval = ext2fs_read_inode(fs, EXT2_RESIZE_INO, &inode); 82 if (retval) 83 goto out_free; 84 85 /* Maximum possible file size (we donly use the dindirect blocks) */ 86 apb = EXT2_ADDR_PER_BLOCK(sb); 87 rsv_add = fs->blocksize / 512; 88 if ((dindir_blk = inode.i_block[EXT2_DIND_BLOCK])) { 89#ifdef RES_GDT_DEBUG 90 printf("reading GDT dindir %u\n", dindir_blk); 91#endif 92 retval = ext2fs_read_ind_block(fs, dindir_blk, dindir_buf); 93 if (retval) 94 goto out_inode; 95 } else { 96 blk_t goal = sb->s_first_data_block + fs->desc_blocks + 97 sb->s_reserved_gdt_blocks + 2 + 98 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 = fs->now ? fs->now : 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 /* FIXME XXX XXX 134 blk_t new_blk; 135 136 retval = ext2fs_new_block(fs, gdt_blk, 0, &new_blk); 137 if (retval) 138 goto out_free; 139 if (new_blk != gdt_blk) { 140 // XXX free block 141 retval = -1; // XXX 142 } 143 */ 144 gdt_dirty = dindir_dirty = inode_dirty = 1; 145 memset(gdt_buf, 0, fs->blocksize); 146 dindir_buf[gdt_off] = gdt_blk; 147 inode.i_blocks += rsv_add; 148#ifdef RES_GDT_DEBUG 149 printf("added primary GDT block %u at %u[%u]\n", 150 gdt_blk, dindir_blk, gdt_off); 151#endif 152 } else if (dindir_buf[gdt_off] == gdt_blk) { 153#ifdef RES_GDT_DEBUG 154 printf("reading primary GDT block %u\n", gdt_blk); 155#endif 156 retval = ext2fs_read_ind_block(fs, gdt_blk, gdt_buf); 157 if (retval) 158 goto out_dindir; 159 } else { 160#ifdef RES_GDT_DEBUG 161 printf("bad primary GDT %u != %u at %u[%u]\n", 162 dindir_buf[gdt_off], gdt_blk,dindir_blk,gdt_off); 163#endif 164 retval = EXT2_ET_RESIZE_INODE_CORRUPT; 165 goto out_dindir; 166 } 167 168 while ((grp = list_backups(fs, &three, &five, &seven)) < 169 fs->group_desc_count) { 170 blk_t expect = gdt_blk + grp * sb->s_blocks_per_group; 171 172 if (!gdt_buf[last]) { 173#ifdef RES_GDT_DEBUG 174 printf("added backup GDT %u grp %u@%u[%u]\n", 175 expect, grp, gdt_blk, last); 176#endif 177 gdt_buf[last] = expect; 178 inode.i_blocks += rsv_add; 179 gdt_dirty = inode_dirty = 1; 180 } else if (gdt_buf[last] != expect) { 181#ifdef RES_GDT_DEBUG 182 printf("bad backup GDT %u != %u at %u[%u]\n", 183 gdt_buf[last], expect, gdt_blk, last); 184#endif 185 retval = EXT2_ET_RESIZE_INODE_CORRUPT; 186 goto out_dindir; 187 } 188 last++; 189 } 190 if (gdt_dirty) { 191#ifdef RES_GDT_DEBUG 192 printf("writing primary GDT block %u\n", gdt_blk); 193#endif 194 retval = ext2fs_write_ind_block(fs, gdt_blk, gdt_buf); 195 if (retval) 196 goto out_dindir; 197 } 198 } 199 200out_dindir: 201 if (dindir_dirty) { 202 retval2 = ext2fs_write_ind_block(fs, dindir_blk, dindir_buf); 203 if (!retval) 204 retval = retval2; 205 } 206out_inode: 207#ifdef RES_GDT_DEBUG 208 printf("inode.i_blocks = %u, i_size = %u\n", inode.i_blocks, 209 inode.i_size); 210#endif 211 if (inode_dirty) { 212 inode.i_atime = inode.i_mtime = fs->now ? fs->now : time(0); 213 retval2 = ext2fs_write_inode(fs, EXT2_RESIZE_INO, &inode); 214 if (!retval) 215 retval = retval2; 216 } 217out_free: 218 ext2fs_free_mem(&dindir_buf); 219 return retval; 220} 221 222