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 */
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 blk_t dindir_blk, rsv_off, gdt_off, gdt_blk;
69 int dindir_dirty = 0, inode_dirty = 0;
70
71 EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
72
73 sb = fs->super;
74
75 retval = ext2fs_get_array(2, fs->blocksize, &dindir_buf);
76 if (retval)
77 goto out_free;
78 gdt_buf = (__u32 *)((char *)dindir_buf + fs->blocksize);
79
80 retval = ext2fs_read_inode(fs, EXT2_RESIZE_INO, &inode);
81 if (retval)
82 goto out_free;
83
84 /* Maximum possible file size (we donly use the dindirect blocks) */
85 apb = EXT2_ADDR_PER_BLOCK(sb);
86 if ((dindir_blk = inode.i_block[EXT2_DIND_BLOCK])) {
87 #ifdef RES_GDT_DEBUG
88 printf("reading GDT dindir %u\n", dindir_blk);
89 #endif
90 retval = ext2fs_read_ind_block(fs, dindir_blk, dindir_buf);
91 if (retval)
92 goto out_inode;
93 } else {
94 blk_t goal = sb->s_first_data_block + fs->desc_blocks +
95 sb->s_reserved_gdt_blocks + 2 +
96 fs->inode_blocks_per_group;
97
98 retval = ext2fs_alloc_block(fs, goal, 0, &dindir_blk);
99 if (retval)
100 goto out_free;
101 inode.i_mode = LINUX_S_IFREG | 0600;
102 inode.i_links_count = 1;
103 inode.i_block[EXT2_DIND_BLOCK] = dindir_blk;
104 ext2fs_iblk_set(fs, &inode, 1);
105 memset(dindir_buf, 0, fs->blocksize);
106 #ifdef RES_GDT_DEBUG
107 printf("allocated GDT dindir %u\n", dindir_blk);
108 #endif
109 dindir_dirty = inode_dirty = 1;
110 inode_size = apb*apb + apb + EXT2_NDIR_BLOCKS;
111 inode_size *= fs->blocksize;
112 inode.i_size = inode_size & 0xFFFFFFFF;
113 inode.i_size_high = (inode_size >> 32) & 0xFFFFFFFF;
114 if(inode.i_size_high) {
115 sb->s_feature_ro_compat |=
116 EXT2_FEATURE_RO_COMPAT_LARGE_FILE;
117 }
118 inode.i_ctime = fs->now ? fs->now : time(0);
119 }
120
121 for (rsv_off = 0, gdt_off = fs->desc_blocks,
122 gdt_blk = sb->s_first_data_block + 1 + fs->desc_blocks;
123 rsv_off < sb->s_reserved_gdt_blocks;
124 rsv_off++, gdt_off++, gdt_blk++) {
125 unsigned int three = 1, five = 5, seven = 7;
126 unsigned int grp, last = 0;
127 int gdt_dirty = 0;
128
129 gdt_off %= apb;
130 if (!dindir_buf[gdt_off]) {
131 /* FIXME XXX XXX
132 blk_t new_blk;
133
134 retval = ext2fs_new_block(fs, gdt_blk, 0, &new_blk);
135 if (retval)
136 goto out_free;
137 if (new_blk != gdt_blk) {
138 // XXX free block
139 retval = -1; // XXX
140 }
141 */
142 gdt_dirty = dindir_dirty = inode_dirty = 1;
143 memset(gdt_buf, 0, fs->blocksize);
144 dindir_buf[gdt_off] = gdt_blk;
145 ext2fs_iblk_add_blocks(fs, &inode, 1);
146 #ifdef RES_GDT_DEBUG
147 printf("added primary GDT block %u at %u[%u]\n",
148 gdt_blk, dindir_blk, gdt_off);
149 #endif
150 } else if (dindir_buf[gdt_off] == gdt_blk) {
151 #ifdef RES_GDT_DEBUG
152 printf("reading primary GDT block %u\n", gdt_blk);
153 #endif
154 retval = ext2fs_read_ind_block(fs, gdt_blk, gdt_buf);
155 if (retval)
156 goto out_dindir;
157 } else {
158 #ifdef RES_GDT_DEBUG
159 printf("bad primary GDT %u != %u at %u[%u]\n",
160 dindir_buf[gdt_off], gdt_blk,dindir_blk,gdt_off);
161 #endif
162 retval = EXT2_ET_RESIZE_INODE_CORRUPT;
163 goto out_dindir;
164 }
165
166 while ((grp = list_backups(fs, &three, &five, &seven)) <
167 fs->group_desc_count) {
168 blk_t expect = gdt_blk + grp * sb->s_blocks_per_group;
169
170 if (!gdt_buf[last]) {
171 #ifdef RES_GDT_DEBUG
172 printf("added backup GDT %u grp %u@%u[%u]\n",
173 expect, grp, gdt_blk, last);
174 #endif
175 gdt_buf[last] = expect;
176 ext2fs_iblk_add_blocks(fs, &inode, 1);
177 gdt_dirty = inode_dirty = 1;
178 } else if (gdt_buf[last] != expect) {
179 #ifdef RES_GDT_DEBUG
180 printf("bad backup GDT %u != %u at %u[%u]\n",
181 gdt_buf[last], expect, gdt_blk, last);
182 #endif
183 retval = EXT2_ET_RESIZE_INODE_CORRUPT;
184 goto out_dindir;
185 }
186 last++;
187 }
188 if (gdt_dirty) {
189 #ifdef RES_GDT_DEBUG
190 printf("writing primary GDT block %u\n", gdt_blk);
191 #endif
192 retval = ext2fs_write_ind_block(fs, gdt_blk, gdt_buf);
193 if (retval)
194 goto out_dindir;
195 }
196 }
197
198 out_dindir:
199 if (dindir_dirty) {
200 retval2 = ext2fs_write_ind_block(fs, dindir_blk, dindir_buf);
201 if (!retval)
202 retval = retval2;
203 }
204 out_inode:
205 #ifdef RES_GDT_DEBUG
206 printf("inode.i_blocks = %u, i_size = %u\n", inode.i_blocks,
207 inode.i_size);
208 #endif
209 if (inode_dirty) {
210 inode.i_atime = inode.i_mtime = fs->now ? fs->now : time(0);
211 retval2 = ext2fs_write_new_inode(fs, EXT2_RESIZE_INO, &inode);
212 if (!retval)
213 retval = retval2;
214 }
215 out_free:
216 ext2fs_free_mem(&dindir_buf);
217 return retval;
218 }
219
220