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_id.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),
67			v1_dqoff(from_kqid(&init_user_ns, dquot->dq_id)));
68
69	v1_disk2mem_dqblk(&dquot->dq_dqb, &dqblk);
70	if (dquot->dq_dqb.dqb_bhardlimit == 0 &&
71	    dquot->dq_dqb.dqb_bsoftlimit == 0 &&
72	    dquot->dq_dqb.dqb_ihardlimit == 0 &&
73	    dquot->dq_dqb.dqb_isoftlimit == 0)
74		set_bit(DQ_FAKE_B, &dquot->dq_flags);
75	dqstats_inc(DQST_READS);
76
77	return 0;
78}
79
80static int v1_commit_dqblk(struct dquot *dquot)
81{
82	short type = dquot->dq_id.type;
83	ssize_t ret;
84	struct v1_disk_dqblk dqblk;
85
86	v1_mem2disk_dqblk(&dqblk, &dquot->dq_dqb);
87	if (((type == USRQUOTA) && uid_eq(dquot->dq_id.uid, GLOBAL_ROOT_UID)) ||
88	    ((type == GRPQUOTA) && gid_eq(dquot->dq_id.gid, GLOBAL_ROOT_GID))) {
89		dqblk.dqb_btime =
90			sb_dqopt(dquot->dq_sb)->info[type].dqi_bgrace;
91		dqblk.dqb_itime =
92			sb_dqopt(dquot->dq_sb)->info[type].dqi_igrace;
93	}
94	ret = 0;
95	if (sb_dqopt(dquot->dq_sb)->files[type])
96		ret = dquot->dq_sb->s_op->quota_write(dquot->dq_sb, type,
97			(char *)&dqblk, sizeof(struct v1_disk_dqblk),
98			v1_dqoff(from_kqid(&init_user_ns, dquot->dq_id)));
99	if (ret != sizeof(struct v1_disk_dqblk)) {
100		quota_error(dquot->dq_sb, "dquota write failed");
101		if (ret >= 0)
102			ret = -EIO;
103		goto out;
104	}
105	ret = 0;
106
107out:
108	dqstats_inc(DQST_WRITES);
109
110	return ret;
111}
112
113/* Magics of new quota format */
114#define V2_INITQMAGICS {\
115	0xd9c01f11,     /* USRQUOTA */\
116	0xd9c01927      /* GRPQUOTA */\
117}
118
119/* Header of new quota format */
120struct v2_disk_dqheader {
121	__le32 dqh_magic;        /* Magic number identifying file */
122	__le32 dqh_version;      /* File version */
123};
124
125static int v1_check_quota_file(struct super_block *sb, int type)
126{
127	struct inode *inode = sb_dqopt(sb)->files[type];
128	ulong blocks;
129	size_t off;
130	struct v2_disk_dqheader dqhead;
131	ssize_t size;
132	loff_t isize;
133	static const uint quota_magics[] = V2_INITQMAGICS;
134
135	isize = i_size_read(inode);
136	if (!isize)
137		return 0;
138	blocks = isize >> BLOCK_SIZE_BITS;
139	off = isize & (BLOCK_SIZE - 1);
140	if ((blocks % sizeof(struct v1_disk_dqblk) * BLOCK_SIZE + off) %
141	    sizeof(struct v1_disk_dqblk))
142		return 0;
143	/* Doublecheck whether we didn't get file with new format - with old
144	 * quotactl() this could happen */
145	size = sb->s_op->quota_read(sb, type, (char *)&dqhead,
146				    sizeof(struct v2_disk_dqheader), 0);
147	if (size != sizeof(struct v2_disk_dqheader))
148		return 1;	/* Probably not new format */
149	if (le32_to_cpu(dqhead.dqh_magic) != quota_magics[type])
150		return 1;	/* Definitely not new format */
151	printk(KERN_INFO
152	       "VFS: %s: Refusing to turn on old quota format on given file."
153	       " It probably contains newer quota format.\n", sb->s_id);
154        return 0;		/* Seems like a new format file -> refuse it */
155}
156
157static int v1_read_file_info(struct super_block *sb, int type)
158{
159	struct quota_info *dqopt = sb_dqopt(sb);
160	struct v1_disk_dqblk dqblk;
161	int ret;
162
163	ret = sb->s_op->quota_read(sb, type, (char *)&dqblk,
164				sizeof(struct v1_disk_dqblk), v1_dqoff(0));
165	if (ret != sizeof(struct v1_disk_dqblk)) {
166		if (ret >= 0)
167			ret = -EIO;
168		goto out;
169	}
170	ret = 0;
171	/* limits are stored as unsigned 32-bit data */
172	dqopt->info[type].dqi_max_spc_limit = 0xffffffffULL << QUOTABLOCK_BITS;
173	dqopt->info[type].dqi_max_ino_limit = 0xffffffff;
174	dqopt->info[type].dqi_igrace =
175			dqblk.dqb_itime ? dqblk.dqb_itime : MAX_IQ_TIME;
176	dqopt->info[type].dqi_bgrace =
177			dqblk.dqb_btime ? dqblk.dqb_btime : MAX_DQ_TIME;
178out:
179	return ret;
180}
181
182static int v1_write_file_info(struct super_block *sb, int type)
183{
184	struct quota_info *dqopt = sb_dqopt(sb);
185	struct v1_disk_dqblk dqblk;
186	int ret;
187
188	dqopt->info[type].dqi_flags &= ~DQF_INFO_DIRTY;
189	ret = sb->s_op->quota_read(sb, type, (char *)&dqblk,
190				sizeof(struct v1_disk_dqblk), v1_dqoff(0));
191	if (ret != sizeof(struct v1_disk_dqblk)) {
192		if (ret >= 0)
193			ret = -EIO;
194		goto out;
195	}
196	dqblk.dqb_itime = dqopt->info[type].dqi_igrace;
197	dqblk.dqb_btime = dqopt->info[type].dqi_bgrace;
198	ret = sb->s_op->quota_write(sb, type, (char *)&dqblk,
199	      sizeof(struct v1_disk_dqblk), v1_dqoff(0));
200	if (ret == sizeof(struct v1_disk_dqblk))
201		ret = 0;
202	else if (ret > 0)
203		ret = -EIO;
204out:
205	return ret;
206}
207
208static const struct quota_format_ops v1_format_ops = {
209	.check_quota_file	= v1_check_quota_file,
210	.read_file_info		= v1_read_file_info,
211	.write_file_info	= v1_write_file_info,
212	.free_file_info		= NULL,
213	.read_dqblk		= v1_read_dqblk,
214	.commit_dqblk		= v1_commit_dqblk,
215};
216
217static struct quota_format_type v1_quota_format = {
218	.qf_fmt_id	= QFMT_VFS_OLD,
219	.qf_ops		= &v1_format_ops,
220	.qf_owner	= THIS_MODULE
221};
222
223static int __init init_v1_quota_format(void)
224{
225        return register_quota_format(&v1_quota_format);
226}
227
228static void __exit exit_v1_quota_format(void)
229{
230        unregister_quota_format(&v1_quota_format);
231}
232
233module_init(init_v1_quota_format);
234module_exit(exit_v1_quota_format);
235
236