1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  *	vfsv0 quota IO operations on file
4  */
5 
6 #include <linux/errno.h>
7 #include <linux/fs.h>
8 #include <linux/mount.h>
9 #include <linux/dqblk_v2.h>
10 #include <linux/kernel.h>
11 #include <linux/init.h>
12 #include <linux/module.h>
13 #include <linux/slab.h>
14 #include <linux/quotaops.h>
15 
16 #include <asm/byteorder.h>
17 
18 #include "quota_tree.h"
19 #include "quotaio_v2.h"
20 
21 MODULE_AUTHOR("Jan Kara");
22 MODULE_DESCRIPTION("Quota format v2 support");
23 MODULE_LICENSE("GPL");
24 
25 static void v2r0_mem2diskdqb(void *dp, struct dquot *dquot);
26 static void v2r0_disk2memdqb(struct dquot *dquot, void *dp);
27 static int v2r0_is_id(void *dp, struct dquot *dquot);
28 static void v2r1_mem2diskdqb(void *dp, struct dquot *dquot);
29 static void v2r1_disk2memdqb(struct dquot *dquot, void *dp);
30 static int v2r1_is_id(void *dp, struct dquot *dquot);
31 
32 static const struct qtree_fmt_operations v2r0_qtree_ops = {
33 	.mem2disk_dqblk = v2r0_mem2diskdqb,
34 	.disk2mem_dqblk = v2r0_disk2memdqb,
35 	.is_id = v2r0_is_id,
36 };
37 
38 static const struct qtree_fmt_operations v2r1_qtree_ops = {
39 	.mem2disk_dqblk = v2r1_mem2diskdqb,
40 	.disk2mem_dqblk = v2r1_disk2memdqb,
41 	.is_id = v2r1_is_id,
42 };
43 
44 #define QUOTABLOCK_BITS 10
45 #define QUOTABLOCK_SIZE (1 << QUOTABLOCK_BITS)
46 
v2_stoqb(qsize_t space)47 static inline qsize_t v2_stoqb(qsize_t space)
48 {
49 	return (space + QUOTABLOCK_SIZE - 1) >> QUOTABLOCK_BITS;
50 }
51 
v2_qbtos(qsize_t blocks)52 static inline qsize_t v2_qbtos(qsize_t blocks)
53 {
54 	return blocks << QUOTABLOCK_BITS;
55 }
56 
v2_read_header(struct super_block * sb,int type,struct v2_disk_dqheader * dqhead)57 static int v2_read_header(struct super_block *sb, int type,
58 			  struct v2_disk_dqheader *dqhead)
59 {
60 	ssize_t size;
61 
62 	size = sb->s_op->quota_read(sb, type, (char *)dqhead,
63 				    sizeof(struct v2_disk_dqheader), 0);
64 	if (size != sizeof(struct v2_disk_dqheader)) {
65 		quota_error(sb, "Failed header read: expected=%zd got=%zd",
66 			    sizeof(struct v2_disk_dqheader), size);
67 		if (size < 0)
68 			return size;
69 		return -EIO;
70 	}
71 	return 0;
72 }
73 
74 /* Check whether given file is really vfsv0 quotafile */
v2_check_quota_file(struct super_block * sb,int type)75 static int v2_check_quota_file(struct super_block *sb, int type)
76 {
77 	struct v2_disk_dqheader dqhead;
78 	static const uint quota_magics[] = V2_INITQMAGICS;
79 	static const uint quota_versions[] = V2_INITQVERSIONS;
80 
81 	if (v2_read_header(sb, type, &dqhead))
82 		return 0;
83 	if (le32_to_cpu(dqhead.dqh_magic) != quota_magics[type] ||
84 	    le32_to_cpu(dqhead.dqh_version) > quota_versions[type])
85 		return 0;
86 	return 1;
87 }
88 
89 /* Read information header from quota file */
v2_read_file_info(struct super_block * sb,int type)90 static int v2_read_file_info(struct super_block *sb, int type)
91 {
92 	struct v2_disk_dqinfo dinfo;
93 	struct v2_disk_dqheader dqhead;
94 	struct quota_info *dqopt = sb_dqopt(sb);
95 	struct mem_dqinfo *info = &dqopt->info[type];
96 	struct qtree_mem_dqinfo *qinfo;
97 	ssize_t size;
98 	unsigned int version;
99 	int ret;
100 
101 	down_read(&dqopt->dqio_sem);
102 	ret = v2_read_header(sb, type, &dqhead);
103 	if (ret < 0)
104 		goto out;
105 	version = le32_to_cpu(dqhead.dqh_version);
106 	if ((info->dqi_fmt_id == QFMT_VFS_V0 && version != 0) ||
107 	    (info->dqi_fmt_id == QFMT_VFS_V1 && version != 1)) {
108 		ret = -EINVAL;
109 		goto out;
110 	}
111 
112 	size = sb->s_op->quota_read(sb, type, (char *)&dinfo,
113 	       sizeof(struct v2_disk_dqinfo), V2_DQINFOOFF);
114 	if (size != sizeof(struct v2_disk_dqinfo)) {
115 		quota_error(sb, "Can't read info structure");
116 		if (size < 0)
117 			ret = size;
118 		else
119 			ret = -EIO;
120 		goto out;
121 	}
122 	info->dqi_priv = kmalloc(sizeof(struct qtree_mem_dqinfo), GFP_NOFS);
123 	if (!info->dqi_priv) {
124 		ret = -ENOMEM;
125 		goto out;
126 	}
127 	qinfo = info->dqi_priv;
128 	if (version == 0) {
129 		/* limits are stored as unsigned 32-bit data */
130 		info->dqi_max_spc_limit = 0xffffffffLL << QUOTABLOCK_BITS;
131 		info->dqi_max_ino_limit = 0xffffffff;
132 	} else {
133 		/*
134 		 * Used space is stored as unsigned 64-bit value in bytes but
135 		 * quota core supports only signed 64-bit values so use that
136 		 * as a limit
137 		 */
138 		info->dqi_max_spc_limit = 0x7fffffffffffffffLL; /* 2^63-1 */
139 		info->dqi_max_ino_limit = 0x7fffffffffffffffLL;
140 	}
141 	info->dqi_bgrace = le32_to_cpu(dinfo.dqi_bgrace);
142 	info->dqi_igrace = le32_to_cpu(dinfo.dqi_igrace);
143 	/* No flags currently supported */
144 	info->dqi_flags = 0;
145 	qinfo->dqi_sb = sb;
146 	qinfo->dqi_type = type;
147 	qinfo->dqi_blocks = le32_to_cpu(dinfo.dqi_blocks);
148 	qinfo->dqi_free_blk = le32_to_cpu(dinfo.dqi_free_blk);
149 	qinfo->dqi_free_entry = le32_to_cpu(dinfo.dqi_free_entry);
150 	qinfo->dqi_blocksize_bits = V2_DQBLKSIZE_BITS;
151 	qinfo->dqi_usable_bs = 1 << V2_DQBLKSIZE_BITS;
152 	qinfo->dqi_qtree_depth = qtree_depth(qinfo);
153 	if (version == 0) {
154 		qinfo->dqi_entry_size = sizeof(struct v2r0_disk_dqblk);
155 		qinfo->dqi_ops = &v2r0_qtree_ops;
156 	} else {
157 		qinfo->dqi_entry_size = sizeof(struct v2r1_disk_dqblk);
158 		qinfo->dqi_ops = &v2r1_qtree_ops;
159 	}
160 	ret = -EUCLEAN;
161 	/* Some sanity checks of the read headers... */
162 	if ((loff_t)qinfo->dqi_blocks << qinfo->dqi_blocksize_bits >
163 	    i_size_read(sb_dqopt(sb)->files[type])) {
164 		quota_error(sb, "Number of blocks too big for quota file size (%llu > %llu).",
165 		    (loff_t)qinfo->dqi_blocks << qinfo->dqi_blocksize_bits,
166 		    i_size_read(sb_dqopt(sb)->files[type]));
167 		goto out_free;
168 	}
169 	if (qinfo->dqi_free_blk >= qinfo->dqi_blocks) {
170 		quota_error(sb, "Free block number too big (%u >= %u).",
171 			    qinfo->dqi_free_blk, qinfo->dqi_blocks);
172 		goto out_free;
173 	}
174 	if (qinfo->dqi_free_entry >= qinfo->dqi_blocks) {
175 		quota_error(sb, "Block with free entry too big (%u >= %u).",
176 			    qinfo->dqi_free_entry, qinfo->dqi_blocks);
177 		goto out_free;
178 	}
179 	ret = 0;
180 out_free:
181 	if (ret) {
182 		kfree(info->dqi_priv);
183 		info->dqi_priv = NULL;
184 	}
185 out:
186 	up_read(&dqopt->dqio_sem);
187 	return ret;
188 }
189 
190 /* Write information header to quota file */
v2_write_file_info(struct super_block * sb,int type)191 static int v2_write_file_info(struct super_block *sb, int type)
192 {
193 	struct v2_disk_dqinfo dinfo;
194 	struct quota_info *dqopt = sb_dqopt(sb);
195 	struct mem_dqinfo *info = &dqopt->info[type];
196 	struct qtree_mem_dqinfo *qinfo = info->dqi_priv;
197 	ssize_t size;
198 
199 	down_write(&dqopt->dqio_sem);
200 	spin_lock(&dq_data_lock);
201 	info->dqi_flags &= ~DQF_INFO_DIRTY;
202 	dinfo.dqi_bgrace = cpu_to_le32(info->dqi_bgrace);
203 	dinfo.dqi_igrace = cpu_to_le32(info->dqi_igrace);
204 	/* No flags currently supported */
205 	dinfo.dqi_flags = cpu_to_le32(0);
206 	spin_unlock(&dq_data_lock);
207 	dinfo.dqi_blocks = cpu_to_le32(qinfo->dqi_blocks);
208 	dinfo.dqi_free_blk = cpu_to_le32(qinfo->dqi_free_blk);
209 	dinfo.dqi_free_entry = cpu_to_le32(qinfo->dqi_free_entry);
210 	size = sb->s_op->quota_write(sb, type, (char *)&dinfo,
211 	       sizeof(struct v2_disk_dqinfo), V2_DQINFOOFF);
212 	up_write(&dqopt->dqio_sem);
213 	if (size != sizeof(struct v2_disk_dqinfo)) {
214 		quota_error(sb, "Can't write info structure");
215 		return -1;
216 	}
217 	return 0;
218 }
219 
v2r0_disk2memdqb(struct dquot * dquot,void * dp)220 static void v2r0_disk2memdqb(struct dquot *dquot, void *dp)
221 {
222 	struct v2r0_disk_dqblk *d = dp, empty;
223 	struct mem_dqblk *m = &dquot->dq_dqb;
224 
225 	m->dqb_ihardlimit = le32_to_cpu(d->dqb_ihardlimit);
226 	m->dqb_isoftlimit = le32_to_cpu(d->dqb_isoftlimit);
227 	m->dqb_curinodes = le32_to_cpu(d->dqb_curinodes);
228 	m->dqb_itime = le64_to_cpu(d->dqb_itime);
229 	m->dqb_bhardlimit = v2_qbtos(le32_to_cpu(d->dqb_bhardlimit));
230 	m->dqb_bsoftlimit = v2_qbtos(le32_to_cpu(d->dqb_bsoftlimit));
231 	m->dqb_curspace = le64_to_cpu(d->dqb_curspace);
232 	m->dqb_btime = le64_to_cpu(d->dqb_btime);
233 	/* We need to escape back all-zero structure */
234 	memset(&empty, 0, sizeof(struct v2r0_disk_dqblk));
235 	empty.dqb_itime = cpu_to_le64(1);
236 	if (!memcmp(&empty, dp, sizeof(struct v2r0_disk_dqblk)))
237 		m->dqb_itime = 0;
238 }
239 
v2r0_mem2diskdqb(void * dp,struct dquot * dquot)240 static void v2r0_mem2diskdqb(void *dp, struct dquot *dquot)
241 {
242 	struct v2r0_disk_dqblk *d = dp;
243 	struct mem_dqblk *m = &dquot->dq_dqb;
244 	struct qtree_mem_dqinfo *info =
245 			sb_dqinfo(dquot->dq_sb, dquot->dq_id.type)->dqi_priv;
246 
247 	d->dqb_ihardlimit = cpu_to_le32(m->dqb_ihardlimit);
248 	d->dqb_isoftlimit = cpu_to_le32(m->dqb_isoftlimit);
249 	d->dqb_curinodes = cpu_to_le32(m->dqb_curinodes);
250 	d->dqb_itime = cpu_to_le64(m->dqb_itime);
251 	d->dqb_bhardlimit = cpu_to_le32(v2_stoqb(m->dqb_bhardlimit));
252 	d->dqb_bsoftlimit = cpu_to_le32(v2_stoqb(m->dqb_bsoftlimit));
253 	d->dqb_curspace = cpu_to_le64(m->dqb_curspace);
254 	d->dqb_btime = cpu_to_le64(m->dqb_btime);
255 	d->dqb_id = cpu_to_le32(from_kqid(&init_user_ns, dquot->dq_id));
256 	if (qtree_entry_unused(info, dp))
257 		d->dqb_itime = cpu_to_le64(1);
258 }
259 
v2r0_is_id(void * dp,struct dquot * dquot)260 static int v2r0_is_id(void *dp, struct dquot *dquot)
261 {
262 	struct v2r0_disk_dqblk *d = dp;
263 	struct qtree_mem_dqinfo *info =
264 			sb_dqinfo(dquot->dq_sb, dquot->dq_id.type)->dqi_priv;
265 
266 	if (qtree_entry_unused(info, dp))
267 		return 0;
268 	return qid_eq(make_kqid(&init_user_ns, dquot->dq_id.type,
269 				le32_to_cpu(d->dqb_id)),
270 		      dquot->dq_id);
271 }
272 
v2r1_disk2memdqb(struct dquot * dquot,void * dp)273 static void v2r1_disk2memdqb(struct dquot *dquot, void *dp)
274 {
275 	struct v2r1_disk_dqblk *d = dp, empty;
276 	struct mem_dqblk *m = &dquot->dq_dqb;
277 
278 	m->dqb_ihardlimit = le64_to_cpu(d->dqb_ihardlimit);
279 	m->dqb_isoftlimit = le64_to_cpu(d->dqb_isoftlimit);
280 	m->dqb_curinodes = le64_to_cpu(d->dqb_curinodes);
281 	m->dqb_itime = le64_to_cpu(d->dqb_itime);
282 	m->dqb_bhardlimit = v2_qbtos(le64_to_cpu(d->dqb_bhardlimit));
283 	m->dqb_bsoftlimit = v2_qbtos(le64_to_cpu(d->dqb_bsoftlimit));
284 	m->dqb_curspace = le64_to_cpu(d->dqb_curspace);
285 	m->dqb_btime = le64_to_cpu(d->dqb_btime);
286 	/* We need to escape back all-zero structure */
287 	memset(&empty, 0, sizeof(struct v2r1_disk_dqblk));
288 	empty.dqb_itime = cpu_to_le64(1);
289 	if (!memcmp(&empty, dp, sizeof(struct v2r1_disk_dqblk)))
290 		m->dqb_itime = 0;
291 }
292 
v2r1_mem2diskdqb(void * dp,struct dquot * dquot)293 static void v2r1_mem2diskdqb(void *dp, struct dquot *dquot)
294 {
295 	struct v2r1_disk_dqblk *d = dp;
296 	struct mem_dqblk *m = &dquot->dq_dqb;
297 	struct qtree_mem_dqinfo *info =
298 			sb_dqinfo(dquot->dq_sb, dquot->dq_id.type)->dqi_priv;
299 
300 	d->dqb_ihardlimit = cpu_to_le64(m->dqb_ihardlimit);
301 	d->dqb_isoftlimit = cpu_to_le64(m->dqb_isoftlimit);
302 	d->dqb_curinodes = cpu_to_le64(m->dqb_curinodes);
303 	d->dqb_itime = cpu_to_le64(m->dqb_itime);
304 	d->dqb_bhardlimit = cpu_to_le64(v2_stoqb(m->dqb_bhardlimit));
305 	d->dqb_bsoftlimit = cpu_to_le64(v2_stoqb(m->dqb_bsoftlimit));
306 	d->dqb_curspace = cpu_to_le64(m->dqb_curspace);
307 	d->dqb_btime = cpu_to_le64(m->dqb_btime);
308 	d->dqb_id = cpu_to_le32(from_kqid(&init_user_ns, dquot->dq_id));
309 	d->dqb_pad = 0;
310 	if (qtree_entry_unused(info, dp))
311 		d->dqb_itime = cpu_to_le64(1);
312 }
313 
v2r1_is_id(void * dp,struct dquot * dquot)314 static int v2r1_is_id(void *dp, struct dquot *dquot)
315 {
316 	struct v2r1_disk_dqblk *d = dp;
317 	struct qtree_mem_dqinfo *info =
318 			sb_dqinfo(dquot->dq_sb, dquot->dq_id.type)->dqi_priv;
319 
320 	if (qtree_entry_unused(info, dp))
321 		return 0;
322 	return qid_eq(make_kqid(&init_user_ns, dquot->dq_id.type,
323 				le32_to_cpu(d->dqb_id)),
324 		      dquot->dq_id);
325 }
326 
v2_read_dquot(struct dquot * dquot)327 static int v2_read_dquot(struct dquot *dquot)
328 {
329 	struct quota_info *dqopt = sb_dqopt(dquot->dq_sb);
330 	int ret;
331 
332 	down_read(&dqopt->dqio_sem);
333 	ret = qtree_read_dquot(
334 			sb_dqinfo(dquot->dq_sb, dquot->dq_id.type)->dqi_priv,
335 			dquot);
336 	up_read(&dqopt->dqio_sem);
337 	return ret;
338 }
339 
v2_write_dquot(struct dquot * dquot)340 static int v2_write_dquot(struct dquot *dquot)
341 {
342 	struct quota_info *dqopt = sb_dqopt(dquot->dq_sb);
343 	int ret;
344 	bool alloc = false;
345 
346 	/*
347 	 * If space for dquot is already allocated, we don't need any
348 	 * protection as we'll only overwrite the place of dquot. We are
349 	 * still protected by concurrent writes of the same dquot by
350 	 * dquot->dq_lock.
351 	 */
352 	if (!dquot->dq_off) {
353 		alloc = true;
354 		down_write(&dqopt->dqio_sem);
355 	} else {
356 		down_read(&dqopt->dqio_sem);
357 	}
358 	ret = qtree_write_dquot(
359 			sb_dqinfo(dquot->dq_sb, dquot->dq_id.type)->dqi_priv,
360 			dquot);
361 	if (alloc)
362 		up_write(&dqopt->dqio_sem);
363 	else
364 		up_read(&dqopt->dqio_sem);
365 	return ret;
366 }
367 
v2_release_dquot(struct dquot * dquot)368 static int v2_release_dquot(struct dquot *dquot)
369 {
370 	struct quota_info *dqopt = sb_dqopt(dquot->dq_sb);
371 	int ret;
372 
373 	down_write(&dqopt->dqio_sem);
374 	ret = qtree_release_dquot(sb_dqinfo(dquot->dq_sb, dquot->dq_id.type)->dqi_priv, dquot);
375 	up_write(&dqopt->dqio_sem);
376 
377 	return ret;
378 }
379 
v2_free_file_info(struct super_block * sb,int type)380 static int v2_free_file_info(struct super_block *sb, int type)
381 {
382 	kfree(sb_dqinfo(sb, type)->dqi_priv);
383 	return 0;
384 }
385 
v2_get_next_id(struct super_block * sb,struct kqid * qid)386 static int v2_get_next_id(struct super_block *sb, struct kqid *qid)
387 {
388 	struct quota_info *dqopt = sb_dqopt(sb);
389 	int ret;
390 
391 	down_read(&dqopt->dqio_sem);
392 	ret = qtree_get_next_id(sb_dqinfo(sb, qid->type)->dqi_priv, qid);
393 	up_read(&dqopt->dqio_sem);
394 	return ret;
395 }
396 
397 static const struct quota_format_ops v2_format_ops = {
398 	.check_quota_file	= v2_check_quota_file,
399 	.read_file_info		= v2_read_file_info,
400 	.write_file_info	= v2_write_file_info,
401 	.free_file_info		= v2_free_file_info,
402 	.read_dqblk		= v2_read_dquot,
403 	.commit_dqblk		= v2_write_dquot,
404 	.release_dqblk		= v2_release_dquot,
405 	.get_next_id		= v2_get_next_id,
406 };
407 
408 static struct quota_format_type v2r0_quota_format = {
409 	.qf_fmt_id	= QFMT_VFS_V0,
410 	.qf_ops		= &v2_format_ops,
411 	.qf_owner	= THIS_MODULE
412 };
413 
414 static struct quota_format_type v2r1_quota_format = {
415 	.qf_fmt_id	= QFMT_VFS_V1,
416 	.qf_ops		= &v2_format_ops,
417 	.qf_owner	= THIS_MODULE
418 };
419 
init_v2_quota_format(void)420 static int __init init_v2_quota_format(void)
421 {
422 	int ret;
423 
424 	ret = register_quota_format(&v2r0_quota_format);
425 	if (ret)
426 		return ret;
427 	return register_quota_format(&v2r1_quota_format);
428 }
429 
exit_v2_quota_format(void)430 static void __exit exit_v2_quota_format(void)
431 {
432 	unregister_quota_format(&v2r0_quota_format);
433 	unregister_quota_format(&v2r1_quota_format);
434 }
435 
436 module_init(init_v2_quota_format);
437 module_exit(exit_v2_quota_format);
438