34b37a67bb16c6c936bd725e5fa79e76ffb2ddc0
[linux-2.6.git] / 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
14 MODULE_AUTHOR("Jan Kara");
15 MODULE_DESCRIPTION("Old quota format support");
16 MODULE_LICENSE("GPL");
17
18 #define QUOTABLOCK_BITS 10
19 #define QUOTABLOCK_SIZE (1 << QUOTABLOCK_BITS)
20
21 static inline qsize_t v1_stoqb(qsize_t space)
22 {
23         return (space + QUOTABLOCK_SIZE - 1) >> QUOTABLOCK_BITS;
24 }
25
26 static inline qsize_t v1_qbtos(qsize_t blocks)
27 {
28         return blocks << QUOTABLOCK_BITS;
29 }
30
31 static 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
43 static 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
55 static 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
79 static 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
105 out:
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 */
118 struct v2_disk_dqheader {
119         __le32 dqh_magic;        /* Magic number identifying file */
120         __le32 dqh_version;      /* File version */
121 };
122
123 static 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
155 static 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;
176 out:
177         return ret;
178 }
179
180 static 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;
202 out:
203         return ret;
204 }
205
206 static 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
215 static 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
221 static int __init init_v1_quota_format(void)
222 {
223         return register_quota_format(&v1_quota_format);
224 }
225
226 static void __exit exit_v1_quota_format(void)
227 {
228         unregister_quota_format(&v1_quota_format);
229 }
230
231 module_init(init_v1_quota_format);
232 module_exit(exit_v1_quota_format);
233