1 // SPDX-License-Identifier: GPL-2.0-only
2 #include <linux/errno.h>
3 #include <linux/fs.h>
4 #include <linux/quota.h>
5 #include <linux/quotaops.h>
6 #include <linux/dqblk_v1.h>
7 #include <linux/kernel.h>
8 #include <linux/init.h>
9 #include <linux/module.h>
10
11 #include <asm/byteorder.h>
12
13 #include "quotaio_v1.h"
14
15 MODULE_AUTHOR("Jan Kara");
16 MODULE_DESCRIPTION("Old quota format support");
17 MODULE_LICENSE("GPL");
18
19 #define QUOTABLOCK_BITS 10
20 #define QUOTABLOCK_SIZE (1 << QUOTABLOCK_BITS)
21
22 static inline qsize_t v1_stoqb(qsize_t space)
23 {
24 return (space + QUOTABLOCK_SIZE - 1) >> QUOTABLOCK_BITS;
25 }
26
27 static inline qsize_t v1_qbtos(qsize_t blocks)
28 {
29 return blocks << QUOTABLOCK_BITS;
30 }
31
32 static void v1_disk2mem_dqblk(struct mem_dqblk *m, struct v1_disk_dqblk *d)
33 {
34 m->dqb_ihardlimit = d->dqb_ihardlimit;
35 m->dqb_isoftlimit = d->dqb_isoftlimit;
36 m->dqb_curinodes = d->dqb_curinodes;
37 m->dqb_bhardlimit = v1_qbtos(d->dqb_bhardlimit);
38 m->dqb_bsoftlimit = v1_qbtos(d->dqb_bsoftlimit);
39 m->dqb_curspace = v1_qbtos(d->dqb_curblocks);
40 m->dqb_itime = d->dqb_itime;
41 m->dqb_btime = d->dqb_btime;
42 }
43
44 static void v1_mem2disk_dqblk(struct v1_disk_dqblk *d, struct mem_dqblk *m)
45 {
46 d->dqb_ihardlimit = m->dqb_ihardlimit;
47 d->dqb_isoftlimit = m->dqb_isoftlimit;
48 d->dqb_curinodes = m->dqb_curinodes;
49 d->dqb_bhardlimit = v1_stoqb(m->dqb_bhardlimit);
50 d->dqb_bsoftlimit = v1_stoqb(m->dqb_bsoftlimit);
51 d->dqb_curblocks = v1_stoqb(m->dqb_curspace);
52 d->dqb_itime = m->dqb_itime;
53 d->dqb_btime = m->dqb_btime;
54 }
55
56 static int v1_read_dqblk(struct dquot *dquot)
57 {
58 int type = dquot->dq_id.type;
59 struct v1_disk_dqblk dqblk;
60 struct quota_info *dqopt = sb_dqopt(dquot->dq_sb);
61
62 if (!dqopt->files[type])
63 return -EINVAL;
64
65 /* Set structure to 0s in case read fails/is after end of file */
66 memset(&dqblk, 0, sizeof(struct v1_disk_dqblk));
67 dquot->dq_sb->s_op->quota_read(dquot->dq_sb, type, (char *)&dqblk,
68 sizeof(struct v1_disk_dqblk),
69 v1_dqoff(from_kqid(&init_user_ns, dquot->dq_id)));
70
71 v1_disk2mem_dqblk(&dquot->dq_dqb, &dqblk);
72 if (dquot->dq_dqb.dqb_bhardlimit == 0 &&
73 dquot->dq_dqb.dqb_bsoftlimit == 0 &&
74 dquot->dq_dqb.dqb_ihardlimit == 0 &&
75 dquot->dq_dqb.dqb_isoftlimit == 0)
76 set_bit(DQ_FAKE_B, &dquot->dq_flags);
77 dqstats_inc(DQST_READS);
78
79 return 0;
80 }
81
82 static int v1_commit_dqblk(struct dquot *dquot)
83 {
84 short type = dquot->dq_id.type;
85 ssize_t ret;
86 struct v1_disk_dqblk dqblk;
87
88 v1_mem2disk_dqblk(&dqblk, &dquot->dq_dqb);
89 if (((type == USRQUOTA) && uid_eq(dquot->dq_id.uid, GLOBAL_ROOT_UID)) ||
90 ((type == GRPQUOTA) && gid_eq(dquot->dq_id.gid, GLOBAL_ROOT_GID))) {
91 dqblk.dqb_btime =
92 sb_dqopt(dquot->dq_sb)->info[type].dqi_bgrace;
93 dqblk.dqb_itime =
94 sb_dqopt(dquot->dq_sb)->info[type].dqi_igrace;
95 }
96 ret = 0;
97 if (sb_dqopt(dquot->dq_sb)->files[type])
98 ret = dquot->dq_sb->s_op->quota_write(dquot->dq_sb, type,
99 (char *)&dqblk, sizeof(struct v1_disk_dqblk),
100 v1_dqoff(from_kqid(&init_user_ns, dquot->dq_id)));
101 if (ret != sizeof(struct v1_disk_dqblk)) {
102 quota_error(dquot->dq_sb, "dquota write failed");
103 if (ret >= 0)
104 ret = -EIO;
105 goto out;
106 }
107 ret = 0;
108
109 out:
110 dqstats_inc(DQST_WRITES);
111
112 return ret;
113 }
114
115 /* Magics of new quota format */
116 #define V2_INITQMAGICS {\
117 0xd9c01f11, /* USRQUOTA */\
118 0xd9c01927 /* GRPQUOTA */\
119 }
120
121 /* Header of new quota format */
122 struct v2_disk_dqheader {
123 __le32 dqh_magic; /* Magic number identifying file */
124 __le32 dqh_version; /* File version */
125 };
126
127 static int v1_check_quota_file(struct super_block *sb, int type)
128 {
129 struct inode *inode = sb_dqopt(sb)->files[type];
130 ulong blocks;
131 size_t off;
132 struct v2_disk_dqheader dqhead;
133 ssize_t size;
134 loff_t isize;
135 static const uint quota_magics[] = V2_INITQMAGICS;
136
137 isize = i_size_read(inode);
138 if (!isize)
139 return 0;
140 blocks = isize >> BLOCK_SIZE_BITS;
141 off = isize & (BLOCK_SIZE - 1);
142 if ((blocks % sizeof(struct v1_disk_dqblk) * BLOCK_SIZE + off) %
143 sizeof(struct v1_disk_dqblk))
144 return 0;
145 /* Doublecheck whether we didn't get file with new format - with old
146 * quotactl() this could happen */
147 size = sb->s_op->quota_read(sb, type, (char *)&dqhead,
148 sizeof(struct v2_disk_dqheader), 0);
149 if (size != sizeof(struct v2_disk_dqheader))
150 return 1; /* Probably not new format */
151 if (le32_to_cpu(dqhead.dqh_magic) != quota_magics[type])
152 return 1; /* Definitely not new format */
153 printk(KERN_INFO
154 "VFS: %s: Refusing to turn on old quota format on given file."
155 " It probably contains newer quota format.\n", sb->s_id);
156 return 0; /* Seems like a new format file -> refuse it */
157 }
158
159 static int v1_read_file_info(struct super_block *sb, int type)
160 {
161 struct quota_info *dqopt = sb_dqopt(sb);
162 struct v1_disk_dqblk dqblk;
163 unsigned int memalloc;
164 int ret;
165
166 down_read(&dqopt->dqio_sem);
167 memalloc = memalloc_nofs_save();
168 ret = sb->s_op->quota_read(sb, type, (char *)&dqblk,
169 sizeof(struct v1_disk_dqblk), v1_dqoff(0));
170 if (ret != sizeof(struct v1_disk_dqblk)) {
171 if (ret >= 0)
172 ret = -EIO;
173 goto out;
174 }
175 ret = 0;
176 /* limits are stored as unsigned 32-bit data */
177 dqopt->info[type].dqi_max_spc_limit = 0xffffffffULL << QUOTABLOCK_BITS;
178 dqopt->info[type].dqi_max_ino_limit = 0xffffffff;
179 dqopt->info[type].dqi_igrace =
180 dqblk.dqb_itime ? dqblk.dqb_itime : MAX_IQ_TIME;
181 dqopt->info[type].dqi_bgrace =
182 dqblk.dqb_btime ? dqblk.dqb_btime : MAX_DQ_TIME;
183 out:
184 memalloc_nofs_restore(memalloc);
185 up_read(&dqopt->dqio_sem);
186 return ret;
187 }
188
189 static int v1_write_file_info(struct super_block *sb, int type)
190 {
191 struct quota_info *dqopt = sb_dqopt(sb);
192 struct v1_disk_dqblk dqblk;
193 unsigned int memalloc;
194 int ret;
195
196 down_write(&dqopt->dqio_sem);
197 memalloc = memalloc_nofs_save();
198 ret = sb->s_op->quota_read(sb, type, (char *)&dqblk,
199 sizeof(struct v1_disk_dqblk), v1_dqoff(0));
200 if (ret != sizeof(struct v1_disk_dqblk)) {
201 if (ret >= 0)
202 ret = -EIO;
203 goto out;
204 }
205 spin_lock(&dq_data_lock);
206 dqopt->info[type].dqi_flags &= ~DQF_INFO_DIRTY;
207 dqblk.dqb_itime = dqopt->info[type].dqi_igrace;
208 dqblk.dqb_btime = dqopt->info[type].dqi_bgrace;
209 spin_unlock(&dq_data_lock);
210 ret = sb->s_op->quota_write(sb, type, (char *)&dqblk,
211 sizeof(struct v1_disk_dqblk), v1_dqoff(0));
212 if (ret == sizeof(struct v1_disk_dqblk))
213 ret = 0;
214 else if (ret >= 0)
215 ret = -EIO;
216 out:
217 memalloc_nofs_restore(memalloc);
218 up_write(&dqopt->dqio_sem);
219 return ret;
220 }
221
222 static const struct quota_format_ops v1_format_ops = {
223 .check_quota_file = v1_check_quota_file,
224 .read_file_info = v1_read_file_info,
225 .write_file_info = v1_write_file_info,
226 .read_dqblk = v1_read_dqblk,
227 .commit_dqblk = v1_commit_dqblk,
228 };
229
230 static struct quota_format_type v1_quota_format = {
231 .qf_fmt_id = QFMT_VFS_OLD,
232 .qf_ops = &v1_format_ops,
233 .qf_owner = THIS_MODULE
234 };
235
236 static int __init init_v1_quota_format(void)
237 {
238 return register_quota_format(&v1_quota_format);
239 }
240
241 static void __exit exit_v1_quota_format(void)
242 {
243 unregister_quota_format(&v1_quota_format);
244 }
245
246 module_init(init_v1_quota_format);
247 module_exit(exit_v1_quota_format);
248
249
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