Root/fs/quota/quota_v1.c

1#include <linux/errno.h>
2#include <linux/fs.h>
3#include <linux/quota.h>
4#include <linux/quotaops.h>
5#include <linux/dqblk_v1.h>
6#include <linux/kernel.h>
7#include <linux/init.h>
8#include <linux/module.h>
9
10#include <asm/byteorder.h>
11
12#include "quotaio_v1.h"
13
14MODULE_AUTHOR("Jan Kara");
15MODULE_DESCRIPTION("Old quota format support");
16MODULE_LICENSE("GPL");
17
18#define QUOTABLOCK_BITS 10
19#define QUOTABLOCK_SIZE (1 << QUOTABLOCK_BITS)
20
21static inline qsize_t v1_stoqb(qsize_t space)
22{
23    return (space + QUOTABLOCK_SIZE - 1) >> QUOTABLOCK_BITS;
24}
25
26static inline qsize_t v1_qbtos(qsize_t blocks)
27{
28    return blocks << QUOTABLOCK_BITS;
29}
30
31static void v1_disk2mem_dqblk(struct mem_dqblk *m, struct v1_disk_dqblk *d)
32{
33    m->dqb_ihardlimit = d->dqb_ihardlimit;
34    m->dqb_isoftlimit = d->dqb_isoftlimit;
35    m->dqb_curinodes = d->dqb_curinodes;
36    m->dqb_bhardlimit = v1_qbtos(d->dqb_bhardlimit);
37    m->dqb_bsoftlimit = v1_qbtos(d->dqb_bsoftlimit);
38    m->dqb_curspace = v1_qbtos(d->dqb_curblocks);
39    m->dqb_itime = d->dqb_itime;
40    m->dqb_btime = d->dqb_btime;
41}
42
43static void v1_mem2disk_dqblk(struct v1_disk_dqblk *d, struct mem_dqblk *m)
44{
45    d->dqb_ihardlimit = m->dqb_ihardlimit;
46    d->dqb_isoftlimit = m->dqb_isoftlimit;
47    d->dqb_curinodes = m->dqb_curinodes;
48    d->dqb_bhardlimit = v1_stoqb(m->dqb_bhardlimit);
49    d->dqb_bsoftlimit = v1_stoqb(m->dqb_bsoftlimit);
50    d->dqb_curblocks = v1_stoqb(m->dqb_curspace);
51    d->dqb_itime = m->dqb_itime;
52    d->dqb_btime = m->dqb_btime;
53}
54
55static int v1_read_dqblk(struct dquot *dquot)
56{
57    int type = dquot->dq_type;
58    struct v1_disk_dqblk dqblk;
59
60    if (!sb_dqopt(dquot->dq_sb)->files[type])
61        return -EINVAL;
62
63    /* Set structure to 0s in case read fails/is after end of file */
64    memset(&dqblk, 0, sizeof(struct v1_disk_dqblk));
65    dquot->dq_sb->s_op->quota_read(dquot->dq_sb, type, (char *)&dqblk,
66            sizeof(struct v1_disk_dqblk), v1_dqoff(dquot->dq_id));
67
68    v1_disk2mem_dqblk(&dquot->dq_dqb, &dqblk);
69    if (dquot->dq_dqb.dqb_bhardlimit == 0 &&
70        dquot->dq_dqb.dqb_bsoftlimit == 0 &&
71        dquot->dq_dqb.dqb_ihardlimit == 0 &&
72        dquot->dq_dqb.dqb_isoftlimit == 0)
73        set_bit(DQ_FAKE_B, &dquot->dq_flags);
74    dqstats_inc(DQST_READS);
75
76    return 0;
77}
78
79static int v1_commit_dqblk(struct dquot *dquot)
80{
81    short type = dquot->dq_type;
82    ssize_t ret;
83    struct v1_disk_dqblk dqblk;
84
85    v1_mem2disk_dqblk(&dqblk, &dquot->dq_dqb);
86    if (dquot->dq_id == 0) {
87        dqblk.dqb_btime =
88            sb_dqopt(dquot->dq_sb)->info[type].dqi_bgrace;
89        dqblk.dqb_itime =
90            sb_dqopt(dquot->dq_sb)->info[type].dqi_igrace;
91    }
92    ret = 0;
93    if (sb_dqopt(dquot->dq_sb)->files[type])
94        ret = dquot->dq_sb->s_op->quota_write(dquot->dq_sb, type,
95            (char *)&dqblk, sizeof(struct v1_disk_dqblk),
96            v1_dqoff(dquot->dq_id));
97    if (ret != sizeof(struct v1_disk_dqblk)) {
98        quota_error(dquot->dq_sb, "dquota write failed");
99        if (ret >= 0)
100            ret = -EIO;
101        goto out;
102    }
103    ret = 0;
104
105out:
106    dqstats_inc(DQST_WRITES);
107
108    return ret;
109}
110
111/* Magics of new quota format */
112#define V2_INITQMAGICS {\
113    0xd9c01f11, /* USRQUOTA */\
114    0xd9c01927 /* GRPQUOTA */\
115}
116
117/* Header of new quota format */
118struct v2_disk_dqheader {
119    __le32 dqh_magic; /* Magic number identifying file */
120    __le32 dqh_version; /* File version */
121};
122
123static int v1_check_quota_file(struct super_block *sb, int type)
124{
125    struct inode *inode = sb_dqopt(sb)->files[type];
126    ulong blocks;
127    size_t off;
128    struct v2_disk_dqheader dqhead;
129    ssize_t size;
130    loff_t isize;
131    static const uint quota_magics[] = V2_INITQMAGICS;
132
133    isize = i_size_read(inode);
134    if (!isize)
135        return 0;
136    blocks = isize >> BLOCK_SIZE_BITS;
137    off = isize & (BLOCK_SIZE - 1);
138    if ((blocks % sizeof(struct v1_disk_dqblk) * BLOCK_SIZE + off) %
139        sizeof(struct v1_disk_dqblk))
140        return 0;
141    /* Doublecheck whether we didn't get file with new format - with old
142     * quotactl() this could happen */
143    size = sb->s_op->quota_read(sb, type, (char *)&dqhead,
144                    sizeof(struct v2_disk_dqheader), 0);
145    if (size != sizeof(struct v2_disk_dqheader))
146        return 1; /* Probably not new format */
147    if (le32_to_cpu(dqhead.dqh_magic) != quota_magics[type])
148        return 1; /* Definitely not new format */
149    printk(KERN_INFO
150           "VFS: %s: Refusing to turn on old quota format on given file."
151           " It probably contains newer quota format.\n", sb->s_id);
152        return 0; /* Seems like a new format file -> refuse it */
153}
154
155static int v1_read_file_info(struct super_block *sb, int type)
156{
157    struct quota_info *dqopt = sb_dqopt(sb);
158    struct v1_disk_dqblk dqblk;
159    int ret;
160
161    ret = sb->s_op->quota_read(sb, type, (char *)&dqblk,
162                sizeof(struct v1_disk_dqblk), v1_dqoff(0));
163    if (ret != sizeof(struct v1_disk_dqblk)) {
164        if (ret >= 0)
165            ret = -EIO;
166        goto out;
167    }
168    ret = 0;
169    /* limits are stored as unsigned 32-bit data */
170    dqopt->info[type].dqi_maxblimit = 0xffffffff;
171    dqopt->info[type].dqi_maxilimit = 0xffffffff;
172    dqopt->info[type].dqi_igrace =
173            dqblk.dqb_itime ? dqblk.dqb_itime : MAX_IQ_TIME;
174    dqopt->info[type].dqi_bgrace =
175            dqblk.dqb_btime ? dqblk.dqb_btime : MAX_DQ_TIME;
176out:
177    return ret;
178}
179
180static int v1_write_file_info(struct super_block *sb, int type)
181{
182    struct quota_info *dqopt = sb_dqopt(sb);
183    struct v1_disk_dqblk dqblk;
184    int ret;
185
186    dqopt->info[type].dqi_flags &= ~DQF_INFO_DIRTY;
187    ret = sb->s_op->quota_read(sb, type, (char *)&dqblk,
188                sizeof(struct v1_disk_dqblk), v1_dqoff(0));
189    if (ret != sizeof(struct v1_disk_dqblk)) {
190        if (ret >= 0)
191            ret = -EIO;
192        goto out;
193    }
194    dqblk.dqb_itime = dqopt->info[type].dqi_igrace;
195    dqblk.dqb_btime = dqopt->info[type].dqi_bgrace;
196    ret = sb->s_op->quota_write(sb, type, (char *)&dqblk,
197          sizeof(struct v1_disk_dqblk), v1_dqoff(0));
198    if (ret == sizeof(struct v1_disk_dqblk))
199        ret = 0;
200    else if (ret > 0)
201        ret = -EIO;
202out:
203    return ret;
204}
205
206static const struct quota_format_ops v1_format_ops = {
207    .check_quota_file = v1_check_quota_file,
208    .read_file_info = v1_read_file_info,
209    .write_file_info = v1_write_file_info,
210    .free_file_info = NULL,
211    .read_dqblk = v1_read_dqblk,
212    .commit_dqblk = v1_commit_dqblk,
213};
214
215static struct quota_format_type v1_quota_format = {
216    .qf_fmt_id = QFMT_VFS_OLD,
217    .qf_ops = &v1_format_ops,
218    .qf_owner = THIS_MODULE
219};
220
221static int __init init_v1_quota_format(void)
222{
223        return register_quota_format(&v1_quota_format);
224}
225
226static void __exit exit_v1_quota_format(void)
227{
228        unregister_quota_format(&v1_quota_format);
229}
230
231module_init(init_v1_quota_format);
232module_exit(exit_v1_quota_format);
233
234

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