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initialize.c 11 KB

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  1. /* vi: set sw=4 ts=4: */
  2. /*
  3. * initialize.c --- initialize a filesystem handle given superblock
  4. * parameters. Used by mke2fs when initializing a filesystem.
  5. *
  6. * Copyright (C) 1994, 1995, 1996 Theodore Ts'o.
  7. *
  8. * %Begin-Header%
  9. * This file may be redistributed under the terms of the GNU Public
  10. * License.
  11. * %End-Header%
  12. */
  13. #include <stdio.h>
  14. #include <string.h>
  15. #if HAVE_UNISTD_H
  16. #include <unistd.h>
  17. #endif
  18. #include <fcntl.h>
  19. #include <time.h>
  20. #if HAVE_SYS_STAT_H
  21. #include <sys/stat.h>
  22. #endif
  23. #if HAVE_SYS_TYPES_H
  24. #include <sys/types.h>
  25. #endif
  26. #include "ext2_fs.h"
  27. #include "ext2fs.h"
  28. #if defined(__linux__) && defined(EXT2_OS_LINUX)
  29. #define CREATOR_OS EXT2_OS_LINUX
  30. #else
  31. #if defined(__GNU__) && defined(EXT2_OS_HURD)
  32. #define CREATOR_OS EXT2_OS_HURD
  33. #else
  34. #if defined(__FreeBSD__) && defined(EXT2_OS_FREEBSD)
  35. #define CREATOR_OS EXT2_OS_FREEBSD
  36. #else
  37. #if defined(LITES) && defined(EXT2_OS_LITES)
  38. #define CREATOR_OS EXT2_OS_LITES
  39. #else
  40. #define CREATOR_OS EXT2_OS_LINUX /* by default */
  41. #endif /* defined(LITES) && defined(EXT2_OS_LITES) */
  42. #endif /* defined(__FreeBSD__) && defined(EXT2_OS_FREEBSD) */
  43. #endif /* defined(__GNU__) && defined(EXT2_OS_HURD) */
  44. #endif /* defined(__linux__) && defined(EXT2_OS_LINUX) */
  45. /*
  46. * Note we override the kernel include file's idea of what the default
  47. * check interval (never) should be. It's a good idea to check at
  48. * least *occasionally*, specially since servers will never rarely get
  49. * to reboot, since Linux is so robust these days. :-)
  50. *
  51. * 180 days (six months) seems like a good value.
  52. */
  53. #ifdef EXT2_DFL_CHECKINTERVAL
  54. #undef EXT2_DFL_CHECKINTERVAL
  55. #endif
  56. #define EXT2_DFL_CHECKINTERVAL (86400L * 180L)
  57. /*
  58. * Calculate the number of GDT blocks to reserve for online filesystem growth.
  59. * The absolute maximum number of GDT blocks we can reserve is determined by
  60. * the number of block pointers that can fit into a single block.
  61. */
  62. static int calc_reserved_gdt_blocks(ext2_filsys fs)
  63. {
  64. struct ext2_super_block *sb = fs->super;
  65. unsigned long bpg = sb->s_blocks_per_group;
  66. unsigned int gdpb = fs->blocksize / sizeof(struct ext2_group_desc);
  67. unsigned long max_blocks = 0xffffffff;
  68. unsigned long rsv_groups;
  69. int rsv_gdb;
  70. /* We set it at 1024x the current filesystem size, or
  71. * the upper block count limit (2^32), whichever is lower.
  72. */
  73. if (sb->s_blocks_count < max_blocks / 1024)
  74. max_blocks = sb->s_blocks_count * 1024;
  75. rsv_groups = (max_blocks - sb->s_first_data_block + bpg - 1) / bpg;
  76. rsv_gdb = (rsv_groups + gdpb - 1) / gdpb - fs->desc_blocks;
  77. if (rsv_gdb > EXT2_ADDR_PER_BLOCK(sb))
  78. rsv_gdb = EXT2_ADDR_PER_BLOCK(sb);
  79. #ifdef RES_GDT_DEBUG
  80. printf("max_blocks %lu, rsv_groups = %lu, rsv_gdb = %lu\n",
  81. max_blocks, rsv_groups, rsv_gdb);
  82. #endif
  83. return rsv_gdb;
  84. }
  85. errcode_t ext2fs_initialize(const char *name, int flags,
  86. struct ext2_super_block *param,
  87. io_manager manager, ext2_filsys *ret_fs)
  88. {
  89. ext2_filsys fs;
  90. errcode_t retval;
  91. struct ext2_super_block *super;
  92. int frags_per_block;
  93. unsigned int rem;
  94. unsigned int overhead = 0;
  95. blk_t group_block;
  96. unsigned int ipg;
  97. dgrp_t i;
  98. blk_t numblocks;
  99. int rsv_gdt;
  100. char *buf;
  101. if (!param || !param->s_blocks_count)
  102. return EXT2_ET_INVALID_ARGUMENT;
  103. retval = ext2fs_get_mem(sizeof(struct struct_ext2_filsys), &fs);
  104. if (retval)
  105. return retval;
  106. memset(fs, 0, sizeof(struct struct_ext2_filsys));
  107. fs->magic = EXT2_ET_MAGIC_EXT2FS_FILSYS;
  108. fs->flags = flags | EXT2_FLAG_RW;
  109. fs->umask = 022;
  110. #ifdef WORDS_BIGENDIAN
  111. fs->flags |= EXT2_FLAG_SWAP_BYTES;
  112. #endif
  113. retval = manager->open(name, IO_FLAG_RW, &fs->io);
  114. if (retval)
  115. goto cleanup;
  116. fs->image_io = fs->io;
  117. fs->io->app_data = fs;
  118. retval = ext2fs_get_mem(strlen(name)+1, &fs->device_name);
  119. if (retval)
  120. goto cleanup;
  121. strcpy(fs->device_name, name);
  122. retval = ext2fs_get_mem(SUPERBLOCK_SIZE, &super);
  123. if (retval)
  124. goto cleanup;
  125. fs->super = super;
  126. memset(super, 0, SUPERBLOCK_SIZE);
  127. #define set_field(field, default) (super->field = param->field ? \
  128. param->field : (default))
  129. super->s_magic = EXT2_SUPER_MAGIC;
  130. super->s_state = EXT2_VALID_FS;
  131. set_field(s_log_block_size, 0); /* default blocksize: 1024 bytes */
  132. set_field(s_log_frag_size, 0); /* default fragsize: 1024 bytes */
  133. set_field(s_first_data_block, super->s_log_block_size ? 0 : 1);
  134. set_field(s_max_mnt_count, EXT2_DFL_MAX_MNT_COUNT);
  135. set_field(s_errors, EXT2_ERRORS_DEFAULT);
  136. set_field(s_feature_compat, 0);
  137. set_field(s_feature_incompat, 0);
  138. set_field(s_feature_ro_compat, 0);
  139. set_field(s_first_meta_bg, 0);
  140. if (super->s_feature_incompat & ~EXT2_LIB_FEATURE_INCOMPAT_SUPP) {
  141. retval = EXT2_ET_UNSUPP_FEATURE;
  142. goto cleanup;
  143. }
  144. if (super->s_feature_ro_compat & ~EXT2_LIB_FEATURE_RO_COMPAT_SUPP) {
  145. retval = EXT2_ET_RO_UNSUPP_FEATURE;
  146. goto cleanup;
  147. }
  148. set_field(s_rev_level, EXT2_GOOD_OLD_REV);
  149. if (super->s_rev_level >= EXT2_DYNAMIC_REV) {
  150. set_field(s_first_ino, EXT2_GOOD_OLD_FIRST_INO);
  151. set_field(s_inode_size, EXT2_GOOD_OLD_INODE_SIZE);
  152. }
  153. set_field(s_checkinterval, EXT2_DFL_CHECKINTERVAL);
  154. super->s_mkfs_time = super->s_lastcheck = time(NULL);
  155. super->s_creator_os = CREATOR_OS;
  156. fs->blocksize = EXT2_BLOCK_SIZE(super);
  157. fs->fragsize = EXT2_FRAG_SIZE(super);
  158. frags_per_block = fs->blocksize / fs->fragsize;
  159. /* default: (fs->blocksize*8) blocks/group, up to 2^16 (GDT limit) */
  160. set_field(s_blocks_per_group, fs->blocksize * 8);
  161. if (super->s_blocks_per_group > EXT2_MAX_BLOCKS_PER_GROUP(super))
  162. super->s_blocks_per_group = EXT2_MAX_BLOCKS_PER_GROUP(super);
  163. super->s_frags_per_group = super->s_blocks_per_group * frags_per_block;
  164. super->s_blocks_count = param->s_blocks_count;
  165. super->s_r_blocks_count = param->s_r_blocks_count;
  166. if (super->s_r_blocks_count >= param->s_blocks_count) {
  167. retval = EXT2_ET_INVALID_ARGUMENT;
  168. goto cleanup;
  169. }
  170. /*
  171. * If we're creating an external journal device, we don't need
  172. * to bother with the rest.
  173. */
  174. if (super->s_feature_incompat & EXT3_FEATURE_INCOMPAT_JOURNAL_DEV) {
  175. fs->group_desc_count = 0;
  176. ext2fs_mark_super_dirty(fs);
  177. *ret_fs = fs;
  178. return 0;
  179. }
  180. retry:
  181. fs->group_desc_count = (super->s_blocks_count -
  182. super->s_first_data_block +
  183. EXT2_BLOCKS_PER_GROUP(super) - 1)
  184. / EXT2_BLOCKS_PER_GROUP(super);
  185. if (fs->group_desc_count == 0) {
  186. retval = EXT2_ET_TOOSMALL;
  187. goto cleanup;
  188. }
  189. fs->desc_blocks = (fs->group_desc_count +
  190. EXT2_DESC_PER_BLOCK(super) - 1)
  191. / EXT2_DESC_PER_BLOCK(super);
  192. i = fs->blocksize >= 4096 ? 1 : 4096 / fs->blocksize;
  193. set_field(s_inodes_count, super->s_blocks_count / i);
  194. /*
  195. * Make sure we have at least EXT2_FIRST_INO + 1 inodes, so
  196. * that we have enough inodes for the filesystem(!)
  197. */
  198. if (super->s_inodes_count < EXT2_FIRST_INODE(super)+1)
  199. super->s_inodes_count = EXT2_FIRST_INODE(super)+1;
  200. /*
  201. * There should be at least as many inodes as the user
  202. * requested. Figure out how many inodes per group that
  203. * should be. But make sure that we don't allocate more than
  204. * one bitmap's worth of inodes each group.
  205. */
  206. ipg = (super->s_inodes_count + fs->group_desc_count - 1) /
  207. fs->group_desc_count;
  208. if (ipg > fs->blocksize * 8) {
  209. if (super->s_blocks_per_group >= 256) {
  210. /* Try again with slightly different parameters */
  211. super->s_blocks_per_group -= 8;
  212. super->s_blocks_count = param->s_blocks_count;
  213. super->s_frags_per_group = super->s_blocks_per_group *
  214. frags_per_block;
  215. goto retry;
  216. } else
  217. return EXT2_ET_TOO_MANY_INODES;
  218. }
  219. if (ipg > (unsigned) EXT2_MAX_INODES_PER_GROUP(super))
  220. ipg = EXT2_MAX_INODES_PER_GROUP(super);
  221. super->s_inodes_per_group = ipg;
  222. if (super->s_inodes_count > ipg * fs->group_desc_count)
  223. super->s_inodes_count = ipg * fs->group_desc_count;
  224. /*
  225. * Make sure the number of inodes per group completely fills
  226. * the inode table blocks in the descriptor. If not, add some
  227. * additional inodes/group. Waste not, want not...
  228. */
  229. fs->inode_blocks_per_group = (((super->s_inodes_per_group *
  230. EXT2_INODE_SIZE(super)) +
  231. EXT2_BLOCK_SIZE(super) - 1) /
  232. EXT2_BLOCK_SIZE(super));
  233. super->s_inodes_per_group = ((fs->inode_blocks_per_group *
  234. EXT2_BLOCK_SIZE(super)) /
  235. EXT2_INODE_SIZE(super));
  236. /*
  237. * Finally, make sure the number of inodes per group is a
  238. * multiple of 8. This is needed to simplify the bitmap
  239. * splicing code.
  240. */
  241. super->s_inodes_per_group &= ~7;
  242. fs->inode_blocks_per_group = (((super->s_inodes_per_group *
  243. EXT2_INODE_SIZE(super)) +
  244. EXT2_BLOCK_SIZE(super) - 1) /
  245. EXT2_BLOCK_SIZE(super));
  246. /*
  247. * adjust inode count to reflect the adjusted inodes_per_group
  248. */
  249. super->s_inodes_count = super->s_inodes_per_group *
  250. fs->group_desc_count;
  251. super->s_free_inodes_count = super->s_inodes_count;
  252. /*
  253. * check the number of reserved group descriptor table blocks
  254. */
  255. if (super->s_feature_compat & EXT2_FEATURE_COMPAT_RESIZE_INODE)
  256. rsv_gdt = calc_reserved_gdt_blocks(fs);
  257. else
  258. rsv_gdt = 0;
  259. set_field(s_reserved_gdt_blocks, rsv_gdt);
  260. if (super->s_reserved_gdt_blocks > EXT2_ADDR_PER_BLOCK(super)) {
  261. retval = EXT2_ET_RES_GDT_BLOCKS;
  262. goto cleanup;
  263. }
  264. /*
  265. * Overhead is the number of bookkeeping blocks per group. It
  266. * includes the superblock backup, the group descriptor
  267. * backups, the inode bitmap, the block bitmap, and the inode
  268. * table.
  269. */
  270. overhead = (int) (2 + fs->inode_blocks_per_group);
  271. if (ext2fs_bg_has_super(fs, fs->group_desc_count - 1))
  272. overhead += 1 + fs->desc_blocks + super->s_reserved_gdt_blocks;
  273. /* This can only happen if the user requested too many inodes */
  274. if (overhead > super->s_blocks_per_group)
  275. return EXT2_ET_TOO_MANY_INODES;
  276. /*
  277. * See if the last group is big enough to support the
  278. * necessary data structures. If not, we need to get rid of
  279. * it.
  280. */
  281. rem = ((super->s_blocks_count - super->s_first_data_block) %
  282. super->s_blocks_per_group);
  283. if ((fs->group_desc_count == 1) && rem && (rem < overhead))
  284. return EXT2_ET_TOOSMALL;
  285. if (rem && (rem < overhead+50)) {
  286. super->s_blocks_count -= rem;
  287. goto retry;
  288. }
  289. /*
  290. * At this point we know how big the filesystem will be. So
  291. * we can do any and all allocations that depend on the block
  292. * count.
  293. */
  294. retval = ext2fs_get_mem(strlen(fs->device_name) + 80, &buf);
  295. if (retval)
  296. goto cleanup;
  297. sprintf(buf, "block bitmap for %s", fs->device_name);
  298. retval = ext2fs_allocate_block_bitmap(fs, buf, &fs->block_map);
  299. if (retval)
  300. goto cleanup;
  301. sprintf(buf, "inode bitmap for %s", fs->device_name);
  302. retval = ext2fs_allocate_inode_bitmap(fs, buf, &fs->inode_map);
  303. if (retval)
  304. goto cleanup;
  305. ext2fs_free_mem(&buf);
  306. retval = ext2fs_get_mem((size_t) fs->desc_blocks * fs->blocksize,
  307. &fs->group_desc);
  308. if (retval)
  309. goto cleanup;
  310. memset(fs->group_desc, 0, (size_t) fs->desc_blocks * fs->blocksize);
  311. /*
  312. * Reserve the superblock and group descriptors for each
  313. * group, and fill in the correct group statistics for group.
  314. * Note that although the block bitmap, inode bitmap, and
  315. * inode table have not been allocated (and in fact won't be
  316. * by this routine), they are accounted for nevertheless.
  317. */
  318. group_block = super->s_first_data_block;
  319. super->s_free_blocks_count = 0;
  320. for (i = 0; i < fs->group_desc_count; i++) {
  321. numblocks = ext2fs_reserve_super_and_bgd(fs, i, fs->block_map);
  322. super->s_free_blocks_count += numblocks;
  323. fs->group_desc[i].bg_free_blocks_count = numblocks;
  324. fs->group_desc[i].bg_free_inodes_count =
  325. fs->super->s_inodes_per_group;
  326. fs->group_desc[i].bg_used_dirs_count = 0;
  327. group_block += super->s_blocks_per_group;
  328. }
  329. ext2fs_mark_super_dirty(fs);
  330. ext2fs_mark_bb_dirty(fs);
  331. ext2fs_mark_ib_dirty(fs);
  332. io_channel_set_blksize(fs->io, fs->blocksize);
  333. *ret_fs = fs;
  334. return 0;
  335. cleanup:
  336. ext2fs_free(fs);
  337. return retval;
  338. }