source: MondoRescue/branches/stable/mindi-busybox/e2fsprogs/ext2fs/res_gdt.c @ 821

Last change on this file since 821 was 821, checked in by Bruno Cornec, 14 years ago

Addition of busybox 1.2.1 as a mindi-busybox new package
This should avoid delivering binary files in mindi not built there (Fedora and Debian are quite serious about that)

File size: 5.7 KB
Line 
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_mem(2 * fs->blocksize, (void *)&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 = 3 + sb->s_reserved_gdt_blocks +
97            fs->desc_blocks + fs->inode_blocks_per_group;
98
99        retval = ext2fs_alloc_block(fs, goal, 0, &dindir_blk);
100        if (retval)
101            goto out_free;
102        inode.i_mode = LINUX_S_IFREG | 0600;
103        inode.i_links_count = 1;
104        inode.i_block[EXT2_DIND_BLOCK] = dindir_blk;
105        inode.i_blocks = rsv_add;
106        memset(dindir_buf, 0, fs->blocksize);
107#ifdef RES_GDT_DEBUG
108        printf("allocated GDT dindir %u\n", dindir_blk);
109#endif
110        dindir_dirty = inode_dirty = 1;
111        inode_size = apb*apb + apb + EXT2_NDIR_BLOCKS;
112        inode_size *= fs->blocksize;
113        inode.i_size = inode_size & 0xFFFFFFFF;
114        inode.i_size_high = (inode_size >> 32) & 0xFFFFFFFF;
115        if(inode.i_size_high) {
116            sb->s_feature_ro_compat |=
117                EXT2_FEATURE_RO_COMPAT_LARGE_FILE;
118        }
119        inode.i_ctime = time(0);
120    }
121
122    for (rsv_off = 0, gdt_off = fs->desc_blocks,
123         gdt_blk = sb->s_first_data_block + 1 + fs->desc_blocks;
124         rsv_off < sb->s_reserved_gdt_blocks;
125         rsv_off++, gdt_off++, gdt_blk++) {
126        unsigned int three = 1, five = 5, seven = 7;
127        unsigned int grp, last = 0;
128        int gdt_dirty = 0;
129
130        gdt_off %= apb;
131        if (!dindir_buf[gdt_off]) {
132            /* FIXME XXX XXX
133            blk_t new_blk;
134
135            retval = ext2fs_new_block(fs, gdt_blk, 0, &new_blk);
136            if (retval)
137                goto out_free;
138            if (new_blk != gdt_blk) {
139                // XXX free block
140                retval = -1; // XXX
141            }
142            */
143            gdt_dirty = dindir_dirty = inode_dirty = 1;
144            memset(gdt_buf, 0, fs->blocksize);
145            dindir_buf[gdt_off] = gdt_blk;
146            inode.i_blocks += rsv_add;
147#ifdef RES_GDT_DEBUG
148            printf("added primary GDT block %u at %u[%u]\n",
149                   gdt_blk, dindir_blk, gdt_off);
150#endif
151        } else if (dindir_buf[gdt_off] == gdt_blk) {
152#ifdef RES_GDT_DEBUG
153            printf("reading primary GDT block %u\n", gdt_blk);
154#endif
155            retval = ext2fs_read_ind_block(fs, gdt_blk, gdt_buf);
156            if (retval)
157                goto out_dindir;
158        } else {
159#ifdef RES_GDT_DEBUG
160            printf("bad primary GDT %u != %u at %u[%u]\n",
161                   dindir_buf[gdt_off], gdt_blk,dindir_blk,gdt_off);
162#endif
163            retval = EXT2_ET_RESIZE_INODE_CORRUPT;
164            goto out_dindir;
165        }
166
167        while ((grp = list_backups(fs, &three, &five, &seven)) <
168               fs->group_desc_count) {
169            blk_t expect = gdt_blk + grp * sb->s_blocks_per_group;
170
171            if (!gdt_buf[last]) {
172#ifdef RES_GDT_DEBUG
173                printf("added backup GDT %u grp %u@%u[%u]\n",
174                       expect, grp, gdt_blk, last);
175#endif
176                gdt_buf[last] = expect;
177                inode.i_blocks += rsv_add;
178                gdt_dirty = inode_dirty = 1;
179            } else if (gdt_buf[last] != expect) {
180#ifdef RES_GDT_DEBUG
181                printf("bad backup GDT %u != %u at %u[%u]\n",
182                       gdt_buf[last], expect, gdt_blk, last);
183#endif
184                retval = EXT2_ET_RESIZE_INODE_CORRUPT;
185                goto out_dindir;
186            }
187            last++;
188        }
189        if (gdt_dirty) {
190#ifdef RES_GDT_DEBUG
191            printf("writing primary GDT block %u\n", gdt_blk);
192#endif
193            retval = ext2fs_write_ind_block(fs, gdt_blk, gdt_buf);
194            if (retval)
195                goto out_dindir;
196        }
197    }
198
199out_dindir:
200    if (dindir_dirty) {
201        retval2 = ext2fs_write_ind_block(fs, dindir_blk, dindir_buf);
202        if (!retval)
203            retval = retval2;
204    }
205out_inode:
206#ifdef RES_GDT_DEBUG
207    printf("inode.i_blocks = %u, i_size = %u\n", inode.i_blocks,
208           inode.i_size);
209#endif
210    if (inode_dirty) {
211        inode.i_atime = inode.i_mtime = time(0);
212        retval2 = ext2fs_write_inode(fs, EXT2_RESIZE_INO, &inode);
213        if (!retval)
214            retval = retval2;
215    }
216out_free:
217    ext2fs_free_mem((void *)&dindir_buf);
218    return retval;
219}
220
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