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 Library
9 * General Public License, version 2.
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 */
list_backups(ext2_filsys fs,unsigned int * three,unsigned int * five,unsigned int * seven)26 static 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 */
ext2fs_create_resize_inode(ext2_filsys fs)61 errcode_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 unsigned long long apb, inode_size;
68 /* FIXME-64 - can't deal with extents */
69 blk_t dindir_blk, rsv_off, gdt_off, gdt_blk;
70 int dindir_dirty = 0, inode_dirty = 0, sb_blk = 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 return retval;
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 /*
86 * File systems with a blocksize of 1024 and bigalloc have
87 * sb->s_first_data_block of 0; yet the superblock is still at
88 * block #1. We compensate for it here.
89 */
90 sb_blk = sb->s_first_data_block;
91 if (fs->blocksize == 1024 && sb_blk == 0)
92 sb_blk = 1;
93
94 /* Maximum possible file size (we donly use the dindirect blocks) */
95 apb = EXT2_ADDR_PER_BLOCK(sb);
96 if ((dindir_blk = inode.i_block[EXT2_DIND_BLOCK])) {
97 #ifdef RES_GDT_DEBUG
98 printf("reading GDT dindir %u\n", dindir_blk);
99 #endif
100 retval = ext2fs_read_ind_block(fs, dindir_blk, dindir_buf);
101 if (retval)
102 goto out_inode;
103 } else {
104 blk_t goal = sb_blk + fs->desc_blocks +
105 sb->s_reserved_gdt_blocks + 2 +
106 fs->inode_blocks_per_group;
107
108 retval = ext2fs_alloc_block(fs, goal, 0, &dindir_blk);
109 if (retval)
110 goto out_free;
111 inode.i_mode = LINUX_S_IFREG | 0600;
112 inode.i_links_count = 1;
113 inode.i_block[EXT2_DIND_BLOCK] = dindir_blk;
114 ext2fs_iblk_set(fs, &inode, 1);
115 memset(dindir_buf, 0, fs->blocksize);
116 #ifdef RES_GDT_DEBUG
117 printf("allocated GDT dindir %u\n", dindir_blk);
118 #endif
119 dindir_dirty = inode_dirty = 1;
120 inode_size = apb*apb + apb + EXT2_NDIR_BLOCKS;
121 inode_size *= fs->blocksize;
122 inode.i_size = inode_size & 0xFFFFFFFF;
123 inode.i_size_high = (inode_size >> 32) & 0xFFFFFFFF;
124 if(inode.i_size_high) {
125 sb->s_feature_ro_compat |=
126 EXT2_FEATURE_RO_COMPAT_LARGE_FILE;
127 }
128 inode.i_ctime = fs->now ? fs->now : time(0);
129 }
130
131 for (rsv_off = 0, gdt_off = fs->desc_blocks,
132 gdt_blk = sb_blk + 1 + fs->desc_blocks;
133 rsv_off < sb->s_reserved_gdt_blocks;
134 rsv_off++, gdt_off++, gdt_blk++) {
135 unsigned int three = 1, five = 5, seven = 7;
136 unsigned int grp, last = 0;
137 int gdt_dirty = 0;
138
139 gdt_off %= apb;
140 if (!dindir_buf[gdt_off]) {
141 /* FIXME XXX XXX
142 blk_t new_blk;
143
144 retval = ext2fs_new_block(fs, gdt_blk, 0, &new_blk);
145 if (retval)
146 goto out_free;
147 if (new_blk != gdt_blk) {
148 // XXX free block
149 retval = -1; // XXX
150 }
151 */
152 gdt_dirty = dindir_dirty = inode_dirty = 1;
153 memset(gdt_buf, 0, fs->blocksize);
154 dindir_buf[gdt_off] = gdt_blk;
155 ext2fs_iblk_add_blocks(fs, &inode, 1);
156 #ifdef RES_GDT_DEBUG
157 printf("added primary GDT block %u at %u[%u]\n",
158 gdt_blk, dindir_blk, gdt_off);
159 #endif
160 } else if (dindir_buf[gdt_off] == gdt_blk) {
161 #ifdef RES_GDT_DEBUG
162 printf("reading primary GDT block %u\n", gdt_blk);
163 #endif
164 retval = ext2fs_read_ind_block(fs, gdt_blk, gdt_buf);
165 if (retval)
166 goto out_dindir;
167 } else {
168 #ifdef RES_GDT_DEBUG
169 printf("bad primary GDT %u != %u at %u[%u]\n",
170 dindir_buf[gdt_off], gdt_blk,dindir_blk,gdt_off);
171 #endif
172 retval = EXT2_ET_RESIZE_INODE_CORRUPT;
173 goto out_dindir;
174 }
175
176 while ((grp = list_backups(fs, &three, &five, &seven)) <
177 fs->group_desc_count) {
178 blk_t expect = gdt_blk + grp * sb->s_blocks_per_group;
179
180 if (!gdt_buf[last]) {
181 #ifdef RES_GDT_DEBUG
182 printf("added backup GDT %u grp %u@%u[%u]\n",
183 expect, grp, gdt_blk, last);
184 #endif
185 gdt_buf[last] = expect;
186 ext2fs_iblk_add_blocks(fs, &inode, 1);
187 gdt_dirty = inode_dirty = 1;
188 } else if (gdt_buf[last] != expect) {
189 #ifdef RES_GDT_DEBUG
190 printf("bad backup GDT %u != %u at %u[%u]\n",
191 gdt_buf[last], expect, gdt_blk, last);
192 #endif
193 retval = EXT2_ET_RESIZE_INODE_CORRUPT;
194 goto out_dindir;
195 }
196 last++;
197 }
198 if (gdt_dirty) {
199 #ifdef RES_GDT_DEBUG
200 printf("writing primary GDT block %u\n", gdt_blk);
201 #endif
202 retval = ext2fs_write_ind_block(fs, gdt_blk, gdt_buf);
203 if (retval)
204 goto out_dindir;
205 }
206 }
207
208 out_dindir:
209 if (dindir_dirty) {
210 retval2 = ext2fs_write_ind_block(fs, dindir_blk, dindir_buf);
211 if (!retval)
212 retval = retval2;
213 }
214 out_inode:
215 #ifdef RES_GDT_DEBUG
216 printf("inode.i_blocks = %u, i_size = %u\n", inode.i_blocks,
217 inode.i_size);
218 #endif
219 if (inode_dirty) {
220 inode.i_atime = inode.i_mtime = fs->now ? fs->now : time(0);
221 retval2 = ext2fs_write_new_inode(fs, EXT2_RESIZE_INO, &inode);
222 if (!retval)
223 retval = retval2;
224 }
225 out_free:
226 ext2fs_free_mem(&dindir_buf);
227 return retval;
228 }
229
230