xref: /linux/fs/quota/quota.c (revision 5c35a02c545a7bbe77f3a1ae337d9e29beed079b)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Quota code necessary even when VFS quota support is not compiled
4  * into the kernel.  The interesting stuff is over in dquot.c, here
5  * we have symbols for initial quotactl(2) handling, the sysctl(2)
6  * variables, etc - things needed even when quota support disabled.
7  */
8 
9 #include <linux/fs.h>
10 #include <linux/namei.h>
11 #include <linux/slab.h>
12 #include <asm/current.h>
13 #include <linux/uaccess.h>
14 #include <linux/kernel.h>
15 #include <linux/security.h>
16 #include <linux/syscalls.h>
17 #include <linux/capability.h>
18 #include <linux/quotaops.h>
19 #include <linux/types.h>
20 #include <linux/writeback.h>
21 
22 static int check_quotactl_permission(struct super_block *sb, int type, int cmd,
23 				     qid_t id)
24 {
25 	switch (cmd) {
26 	/* these commands do not require any special privilegues */
27 	case Q_GETFMT:
28 	case Q_SYNC:
29 	case Q_GETINFO:
30 	case Q_XGETQSTAT:
31 	case Q_XGETQSTATV:
32 	case Q_XQUOTASYNC:
33 		break;
34 	/* allow to query information for dquots we "own" */
35 	case Q_GETQUOTA:
36 	case Q_XGETQUOTA:
37 		if ((type == USRQUOTA && uid_eq(current_euid(), make_kuid(current_user_ns(), id))) ||
38 		    (type == GRPQUOTA && in_egroup_p(make_kgid(current_user_ns(), id))))
39 			break;
40 		/*FALLTHROUGH*/
41 	default:
42 		if (!capable(CAP_SYS_ADMIN))
43 			return -EPERM;
44 	}
45 
46 	return security_quotactl(cmd, type, id, sb);
47 }
48 
49 static void quota_sync_one(struct super_block *sb, void *arg)
50 {
51 	int type = *(int *)arg;
52 
53 	if (sb->s_qcop && sb->s_qcop->quota_sync &&
54 	    (sb->s_quota_types & (1 << type)))
55 		sb->s_qcop->quota_sync(sb, type);
56 }
57 
58 static int quota_sync_all(int type)
59 {
60 	int ret;
61 
62 	if (type >= MAXQUOTAS)
63 		return -EINVAL;
64 	ret = security_quotactl(Q_SYNC, type, 0, NULL);
65 	if (!ret)
66 		iterate_supers(quota_sync_one, &type);
67 	return ret;
68 }
69 
70 unsigned int qtype_enforce_flag(int type)
71 {
72 	switch (type) {
73 	case USRQUOTA:
74 		return FS_QUOTA_UDQ_ENFD;
75 	case GRPQUOTA:
76 		return FS_QUOTA_GDQ_ENFD;
77 	case PRJQUOTA:
78 		return FS_QUOTA_PDQ_ENFD;
79 	}
80 	return 0;
81 }
82 
83 static int quota_quotaon(struct super_block *sb, int type, qid_t id,
84 		         const struct path *path)
85 {
86 	if (!sb->s_qcop->quota_on && !sb->s_qcop->quota_enable)
87 		return -ENOSYS;
88 	if (sb->s_qcop->quota_enable)
89 		return sb->s_qcop->quota_enable(sb, qtype_enforce_flag(type));
90 	if (IS_ERR(path))
91 		return PTR_ERR(path);
92 	return sb->s_qcop->quota_on(sb, type, id, path);
93 }
94 
95 static int quota_quotaoff(struct super_block *sb, int type)
96 {
97 	if (!sb->s_qcop->quota_off && !sb->s_qcop->quota_disable)
98 		return -ENOSYS;
99 	if (sb->s_qcop->quota_disable)
100 		return sb->s_qcop->quota_disable(sb, qtype_enforce_flag(type));
101 	return sb->s_qcop->quota_off(sb, type);
102 }
103 
104 static int quota_getfmt(struct super_block *sb, int type, void __user *addr)
105 {
106 	__u32 fmt;
107 
108 	if (!sb_has_quota_active(sb, type))
109 		return -ESRCH;
110 	fmt = sb_dqopt(sb)->info[type].dqi_format->qf_fmt_id;
111 	if (copy_to_user(addr, &fmt, sizeof(fmt)))
112 		return -EFAULT;
113 	return 0;
114 }
115 
116 static int quota_getinfo(struct super_block *sb, int type, void __user *addr)
117 {
118 	struct qc_state state;
119 	struct qc_type_state *tstate;
120 	struct if_dqinfo uinfo;
121 	int ret;
122 
123 	/* This checks whether qc_state has enough entries... */
124 	BUILD_BUG_ON(MAXQUOTAS > XQM_MAXQUOTAS);
125 	if (!sb->s_qcop->get_state)
126 		return -ENOSYS;
127 	ret = sb->s_qcop->get_state(sb, &state);
128 	if (ret)
129 		return ret;
130 	tstate = state.s_state + type;
131 	if (!(tstate->flags & QCI_ACCT_ENABLED))
132 		return -ESRCH;
133 	memset(&uinfo, 0, sizeof(uinfo));
134 	uinfo.dqi_bgrace = tstate->spc_timelimit;
135 	uinfo.dqi_igrace = tstate->ino_timelimit;
136 	if (tstate->flags & QCI_SYSFILE)
137 		uinfo.dqi_flags |= DQF_SYS_FILE;
138 	if (tstate->flags & QCI_ROOT_SQUASH)
139 		uinfo.dqi_flags |= DQF_ROOT_SQUASH;
140 	uinfo.dqi_valid = IIF_ALL;
141 	if (copy_to_user(addr, &uinfo, sizeof(uinfo)))
142 		return -EFAULT;
143 	return 0;
144 }
145 
146 static int quota_setinfo(struct super_block *sb, int type, void __user *addr)
147 {
148 	struct if_dqinfo info;
149 	struct qc_info qinfo;
150 
151 	if (copy_from_user(&info, addr, sizeof(info)))
152 		return -EFAULT;
153 	if (!sb->s_qcop->set_info)
154 		return -ENOSYS;
155 	if (info.dqi_valid & ~(IIF_FLAGS | IIF_BGRACE | IIF_IGRACE))
156 		return -EINVAL;
157 	memset(&qinfo, 0, sizeof(qinfo));
158 	if (info.dqi_valid & IIF_FLAGS) {
159 		if (info.dqi_flags & ~DQF_SETINFO_MASK)
160 			return -EINVAL;
161 		if (info.dqi_flags & DQF_ROOT_SQUASH)
162 			qinfo.i_flags |= QCI_ROOT_SQUASH;
163 		qinfo.i_fieldmask |= QC_FLAGS;
164 	}
165 	if (info.dqi_valid & IIF_BGRACE) {
166 		qinfo.i_spc_timelimit = info.dqi_bgrace;
167 		qinfo.i_fieldmask |= QC_SPC_TIMER;
168 	}
169 	if (info.dqi_valid & IIF_IGRACE) {
170 		qinfo.i_ino_timelimit = info.dqi_igrace;
171 		qinfo.i_fieldmask |= QC_INO_TIMER;
172 	}
173 	return sb->s_qcop->set_info(sb, type, &qinfo);
174 }
175 
176 static inline qsize_t qbtos(qsize_t blocks)
177 {
178 	return blocks << QIF_DQBLKSIZE_BITS;
179 }
180 
181 static inline qsize_t stoqb(qsize_t space)
182 {
183 	return (space + QIF_DQBLKSIZE - 1) >> QIF_DQBLKSIZE_BITS;
184 }
185 
186 static void copy_to_if_dqblk(struct if_dqblk *dst, struct qc_dqblk *src)
187 {
188 	memset(dst, 0, sizeof(*dst));
189 	dst->dqb_bhardlimit = stoqb(src->d_spc_hardlimit);
190 	dst->dqb_bsoftlimit = stoqb(src->d_spc_softlimit);
191 	dst->dqb_curspace = src->d_space;
192 	dst->dqb_ihardlimit = src->d_ino_hardlimit;
193 	dst->dqb_isoftlimit = src->d_ino_softlimit;
194 	dst->dqb_curinodes = src->d_ino_count;
195 	dst->dqb_btime = src->d_spc_timer;
196 	dst->dqb_itime = src->d_ino_timer;
197 	dst->dqb_valid = QIF_ALL;
198 }
199 
200 static int quota_getquota(struct super_block *sb, int type, qid_t id,
201 			  void __user *addr)
202 {
203 	struct kqid qid;
204 	struct qc_dqblk fdq;
205 	struct if_dqblk idq;
206 	int ret;
207 
208 	if (!sb->s_qcop->get_dqblk)
209 		return -ENOSYS;
210 	qid = make_kqid(current_user_ns(), type, id);
211 	if (!qid_has_mapping(sb->s_user_ns, qid))
212 		return -EINVAL;
213 	ret = sb->s_qcop->get_dqblk(sb, qid, &fdq);
214 	if (ret)
215 		return ret;
216 	copy_to_if_dqblk(&idq, &fdq);
217 	if (copy_to_user(addr, &idq, sizeof(idq)))
218 		return -EFAULT;
219 	return 0;
220 }
221 
222 /*
223  * Return quota for next active quota >= this id, if any exists,
224  * otherwise return -ENOENT via ->get_nextdqblk
225  */
226 static int quota_getnextquota(struct super_block *sb, int type, qid_t id,
227 			  void __user *addr)
228 {
229 	struct kqid qid;
230 	struct qc_dqblk fdq;
231 	struct if_nextdqblk idq;
232 	int ret;
233 
234 	if (!sb->s_qcop->get_nextdqblk)
235 		return -ENOSYS;
236 	qid = make_kqid(current_user_ns(), type, id);
237 	if (!qid_has_mapping(sb->s_user_ns, qid))
238 		return -EINVAL;
239 	ret = sb->s_qcop->get_nextdqblk(sb, &qid, &fdq);
240 	if (ret)
241 		return ret;
242 	/* struct if_nextdqblk is a superset of struct if_dqblk */
243 	copy_to_if_dqblk((struct if_dqblk *)&idq, &fdq);
244 	idq.dqb_id = from_kqid(current_user_ns(), qid);
245 	if (copy_to_user(addr, &idq, sizeof(idq)))
246 		return -EFAULT;
247 	return 0;
248 }
249 
250 static void copy_from_if_dqblk(struct qc_dqblk *dst, struct if_dqblk *src)
251 {
252 	dst->d_spc_hardlimit = qbtos(src->dqb_bhardlimit);
253 	dst->d_spc_softlimit = qbtos(src->dqb_bsoftlimit);
254 	dst->d_space = src->dqb_curspace;
255 	dst->d_ino_hardlimit = src->dqb_ihardlimit;
256 	dst->d_ino_softlimit = src->dqb_isoftlimit;
257 	dst->d_ino_count = src->dqb_curinodes;
258 	dst->d_spc_timer = src->dqb_btime;
259 	dst->d_ino_timer = src->dqb_itime;
260 
261 	dst->d_fieldmask = 0;
262 	if (src->dqb_valid & QIF_BLIMITS)
263 		dst->d_fieldmask |= QC_SPC_SOFT | QC_SPC_HARD;
264 	if (src->dqb_valid & QIF_SPACE)
265 		dst->d_fieldmask |= QC_SPACE;
266 	if (src->dqb_valid & QIF_ILIMITS)
267 		dst->d_fieldmask |= QC_INO_SOFT | QC_INO_HARD;
268 	if (src->dqb_valid & QIF_INODES)
269 		dst->d_fieldmask |= QC_INO_COUNT;
270 	if (src->dqb_valid & QIF_BTIME)
271 		dst->d_fieldmask |= QC_SPC_TIMER;
272 	if (src->dqb_valid & QIF_ITIME)
273 		dst->d_fieldmask |= QC_INO_TIMER;
274 }
275 
276 static int quota_setquota(struct super_block *sb, int type, qid_t id,
277 			  void __user *addr)
278 {
279 	struct qc_dqblk fdq;
280 	struct if_dqblk idq;
281 	struct kqid qid;
282 
283 	if (copy_from_user(&idq, addr, sizeof(idq)))
284 		return -EFAULT;
285 	if (!sb->s_qcop->set_dqblk)
286 		return -ENOSYS;
287 	qid = make_kqid(current_user_ns(), type, id);
288 	if (!qid_has_mapping(sb->s_user_ns, qid))
289 		return -EINVAL;
290 	copy_from_if_dqblk(&fdq, &idq);
291 	return sb->s_qcop->set_dqblk(sb, qid, &fdq);
292 }
293 
294 static int quota_enable(struct super_block *sb, void __user *addr)
295 {
296 	__u32 flags;
297 
298 	if (copy_from_user(&flags, addr, sizeof(flags)))
299 		return -EFAULT;
300 	if (!sb->s_qcop->quota_enable)
301 		return -ENOSYS;
302 	return sb->s_qcop->quota_enable(sb, flags);
303 }
304 
305 static int quota_disable(struct super_block *sb, void __user *addr)
306 {
307 	__u32 flags;
308 
309 	if (copy_from_user(&flags, addr, sizeof(flags)))
310 		return -EFAULT;
311 	if (!sb->s_qcop->quota_disable)
312 		return -ENOSYS;
313 	return sb->s_qcop->quota_disable(sb, flags);
314 }
315 
316 static int quota_state_to_flags(struct qc_state *state)
317 {
318 	int flags = 0;
319 
320 	if (state->s_state[USRQUOTA].flags & QCI_ACCT_ENABLED)
321 		flags |= FS_QUOTA_UDQ_ACCT;
322 	if (state->s_state[USRQUOTA].flags & QCI_LIMITS_ENFORCED)
323 		flags |= FS_QUOTA_UDQ_ENFD;
324 	if (state->s_state[GRPQUOTA].flags & QCI_ACCT_ENABLED)
325 		flags |= FS_QUOTA_GDQ_ACCT;
326 	if (state->s_state[GRPQUOTA].flags & QCI_LIMITS_ENFORCED)
327 		flags |= FS_QUOTA_GDQ_ENFD;
328 	if (state->s_state[PRJQUOTA].flags & QCI_ACCT_ENABLED)
329 		flags |= FS_QUOTA_PDQ_ACCT;
330 	if (state->s_state[PRJQUOTA].flags & QCI_LIMITS_ENFORCED)
331 		flags |= FS_QUOTA_PDQ_ENFD;
332 	return flags;
333 }
334 
335 static int quota_getstate(struct super_block *sb, struct fs_quota_stat *fqs)
336 {
337 	int type;
338 	struct qc_state state;
339 	int ret;
340 
341 	memset(&state, 0, sizeof (struct qc_state));
342 	ret = sb->s_qcop->get_state(sb, &state);
343 	if (ret < 0)
344 		return ret;
345 
346 	memset(fqs, 0, sizeof(*fqs));
347 	fqs->qs_version = FS_QSTAT_VERSION;
348 	fqs->qs_flags = quota_state_to_flags(&state);
349 	/* No quota enabled? */
350 	if (!fqs->qs_flags)
351 		return -ENOSYS;
352 	fqs->qs_incoredqs = state.s_incoredqs;
353 	/*
354 	 * GETXSTATE quotactl has space for just one set of time limits so
355 	 * report them for the first enabled quota type
356 	 */
357 	for (type = 0; type < XQM_MAXQUOTAS; type++)
358 		if (state.s_state[type].flags & QCI_ACCT_ENABLED)
359 			break;
360 	BUG_ON(type == XQM_MAXQUOTAS);
361 	fqs->qs_btimelimit = state.s_state[type].spc_timelimit;
362 	fqs->qs_itimelimit = state.s_state[type].ino_timelimit;
363 	fqs->qs_rtbtimelimit = state.s_state[type].rt_spc_timelimit;
364 	fqs->qs_bwarnlimit = state.s_state[type].spc_warnlimit;
365 	fqs->qs_iwarnlimit = state.s_state[type].ino_warnlimit;
366 
367 	/* Inodes may be allocated even if inactive; copy out if present */
368 	if (state.s_state[USRQUOTA].ino) {
369 		fqs->qs_uquota.qfs_ino = state.s_state[USRQUOTA].ino;
370 		fqs->qs_uquota.qfs_nblks = state.s_state[USRQUOTA].blocks;
371 		fqs->qs_uquota.qfs_nextents = state.s_state[USRQUOTA].nextents;
372 	}
373 	if (state.s_state[GRPQUOTA].ino) {
374 		fqs->qs_gquota.qfs_ino = state.s_state[GRPQUOTA].ino;
375 		fqs->qs_gquota.qfs_nblks = state.s_state[GRPQUOTA].blocks;
376 		fqs->qs_gquota.qfs_nextents = state.s_state[GRPQUOTA].nextents;
377 	}
378 	if (state.s_state[PRJQUOTA].ino) {
379 		/*
380 		 * Q_XGETQSTAT doesn't have room for both group and project
381 		 * quotas.  So, allow the project quota values to be copied out
382 		 * only if there is no group quota information available.
383 		 */
384 		if (!(state.s_state[GRPQUOTA].flags & QCI_ACCT_ENABLED)) {
385 			fqs->qs_gquota.qfs_ino = state.s_state[PRJQUOTA].ino;
386 			fqs->qs_gquota.qfs_nblks =
387 					state.s_state[PRJQUOTA].blocks;
388 			fqs->qs_gquota.qfs_nextents =
389 					state.s_state[PRJQUOTA].nextents;
390 		}
391 	}
392 	return 0;
393 }
394 
395 static int quota_getxstate(struct super_block *sb, void __user *addr)
396 {
397 	struct fs_quota_stat fqs;
398 	int ret;
399 
400 	if (!sb->s_qcop->get_state)
401 		return -ENOSYS;
402 	ret = quota_getstate(sb, &fqs);
403 	if (!ret && copy_to_user(addr, &fqs, sizeof(fqs)))
404 		return -EFAULT;
405 	return ret;
406 }
407 
408 static int quota_getstatev(struct super_block *sb, struct fs_quota_statv *fqs)
409 {
410 	int type;
411 	struct qc_state state;
412 	int ret;
413 
414 	memset(&state, 0, sizeof (struct qc_state));
415 	ret = sb->s_qcop->get_state(sb, &state);
416 	if (ret < 0)
417 		return ret;
418 
419 	memset(fqs, 0, sizeof(*fqs));
420 	fqs->qs_version = FS_QSTAT_VERSION;
421 	fqs->qs_flags = quota_state_to_flags(&state);
422 	/* No quota enabled? */
423 	if (!fqs->qs_flags)
424 		return -ENOSYS;
425 	fqs->qs_incoredqs = state.s_incoredqs;
426 	/*
427 	 * GETXSTATV quotactl has space for just one set of time limits so
428 	 * report them for the first enabled quota type
429 	 */
430 	for (type = 0; type < XQM_MAXQUOTAS; type++)
431 		if (state.s_state[type].flags & QCI_ACCT_ENABLED)
432 			break;
433 	BUG_ON(type == XQM_MAXQUOTAS);
434 	fqs->qs_btimelimit = state.s_state[type].spc_timelimit;
435 	fqs->qs_itimelimit = state.s_state[type].ino_timelimit;
436 	fqs->qs_rtbtimelimit = state.s_state[type].rt_spc_timelimit;
437 	fqs->qs_bwarnlimit = state.s_state[type].spc_warnlimit;
438 	fqs->qs_iwarnlimit = state.s_state[type].ino_warnlimit;
439 
440 	/* Inodes may be allocated even if inactive; copy out if present */
441 	if (state.s_state[USRQUOTA].ino) {
442 		fqs->qs_uquota.qfs_ino = state.s_state[USRQUOTA].ino;
443 		fqs->qs_uquota.qfs_nblks = state.s_state[USRQUOTA].blocks;
444 		fqs->qs_uquota.qfs_nextents = state.s_state[USRQUOTA].nextents;
445 	}
446 	if (state.s_state[GRPQUOTA].ino) {
447 		fqs->qs_gquota.qfs_ino = state.s_state[GRPQUOTA].ino;
448 		fqs->qs_gquota.qfs_nblks = state.s_state[GRPQUOTA].blocks;
449 		fqs->qs_gquota.qfs_nextents = state.s_state[GRPQUOTA].nextents;
450 	}
451 	if (state.s_state[PRJQUOTA].ino) {
452 		fqs->qs_pquota.qfs_ino = state.s_state[PRJQUOTA].ino;
453 		fqs->qs_pquota.qfs_nblks = state.s_state[PRJQUOTA].blocks;
454 		fqs->qs_pquota.qfs_nextents = state.s_state[PRJQUOTA].nextents;
455 	}
456 	return 0;
457 }
458 
459 static int quota_getxstatev(struct super_block *sb, void __user *addr)
460 {
461 	struct fs_quota_statv fqs;
462 	int ret;
463 
464 	if (!sb->s_qcop->get_state)
465 		return -ENOSYS;
466 
467 	memset(&fqs, 0, sizeof(fqs));
468 	if (copy_from_user(&fqs, addr, 1)) /* Just read qs_version */
469 		return -EFAULT;
470 
471 	/* If this kernel doesn't support user specified version, fail */
472 	switch (fqs.qs_version) {
473 	case FS_QSTATV_VERSION1:
474 		break;
475 	default:
476 		return -EINVAL;
477 	}
478 	ret = quota_getstatev(sb, &fqs);
479 	if (!ret && copy_to_user(addr, &fqs, sizeof(fqs)))
480 		return -EFAULT;
481 	return ret;
482 }
483 
484 /*
485  * XFS defines BBTOB and BTOBB macros inside fs/xfs/ and we cannot move them
486  * out of there as xfsprogs rely on definitions being in that header file. So
487  * just define same functions here for quota purposes.
488  */
489 #define XFS_BB_SHIFT 9
490 
491 static inline u64 quota_bbtob(u64 blocks)
492 {
493 	return blocks << XFS_BB_SHIFT;
494 }
495 
496 static inline u64 quota_btobb(u64 bytes)
497 {
498 	return (bytes + (1 << XFS_BB_SHIFT) - 1) >> XFS_BB_SHIFT;
499 }
500 
501 static void copy_from_xfs_dqblk(struct qc_dqblk *dst, struct fs_disk_quota *src)
502 {
503 	dst->d_spc_hardlimit = quota_bbtob(src->d_blk_hardlimit);
504 	dst->d_spc_softlimit = quota_bbtob(src->d_blk_softlimit);
505 	dst->d_ino_hardlimit = src->d_ino_hardlimit;
506 	dst->d_ino_softlimit = src->d_ino_softlimit;
507 	dst->d_space = quota_bbtob(src->d_bcount);
508 	dst->d_ino_count = src->d_icount;
509 	dst->d_ino_timer = src->d_itimer;
510 	dst->d_spc_timer = src->d_btimer;
511 	dst->d_ino_warns = src->d_iwarns;
512 	dst->d_spc_warns = src->d_bwarns;
513 	dst->d_rt_spc_hardlimit = quota_bbtob(src->d_rtb_hardlimit);
514 	dst->d_rt_spc_softlimit = quota_bbtob(src->d_rtb_softlimit);
515 	dst->d_rt_space = quota_bbtob(src->d_rtbcount);
516 	dst->d_rt_spc_timer = src->d_rtbtimer;
517 	dst->d_rt_spc_warns = src->d_rtbwarns;
518 	dst->d_fieldmask = 0;
519 	if (src->d_fieldmask & FS_DQ_ISOFT)
520 		dst->d_fieldmask |= QC_INO_SOFT;
521 	if (src->d_fieldmask & FS_DQ_IHARD)
522 		dst->d_fieldmask |= QC_INO_HARD;
523 	if (src->d_fieldmask & FS_DQ_BSOFT)
524 		dst->d_fieldmask |= QC_SPC_SOFT;
525 	if (src->d_fieldmask & FS_DQ_BHARD)
526 		dst->d_fieldmask |= QC_SPC_HARD;
527 	if (src->d_fieldmask & FS_DQ_RTBSOFT)
528 		dst->d_fieldmask |= QC_RT_SPC_SOFT;
529 	if (src->d_fieldmask & FS_DQ_RTBHARD)
530 		dst->d_fieldmask |= QC_RT_SPC_HARD;
531 	if (src->d_fieldmask & FS_DQ_BTIMER)
532 		dst->d_fieldmask |= QC_SPC_TIMER;
533 	if (src->d_fieldmask & FS_DQ_ITIMER)
534 		dst->d_fieldmask |= QC_INO_TIMER;
535 	if (src->d_fieldmask & FS_DQ_RTBTIMER)
536 		dst->d_fieldmask |= QC_RT_SPC_TIMER;
537 	if (src->d_fieldmask & FS_DQ_BWARNS)
538 		dst->d_fieldmask |= QC_SPC_WARNS;
539 	if (src->d_fieldmask & FS_DQ_IWARNS)
540 		dst->d_fieldmask |= QC_INO_WARNS;
541 	if (src->d_fieldmask & FS_DQ_RTBWARNS)
542 		dst->d_fieldmask |= QC_RT_SPC_WARNS;
543 	if (src->d_fieldmask & FS_DQ_BCOUNT)
544 		dst->d_fieldmask |= QC_SPACE;
545 	if (src->d_fieldmask & FS_DQ_ICOUNT)
546 		dst->d_fieldmask |= QC_INO_COUNT;
547 	if (src->d_fieldmask & FS_DQ_RTBCOUNT)
548 		dst->d_fieldmask |= QC_RT_SPACE;
549 }
550 
551 static void copy_qcinfo_from_xfs_dqblk(struct qc_info *dst,
552 				       struct fs_disk_quota *src)
553 {
554 	memset(dst, 0, sizeof(*dst));
555 	dst->i_spc_timelimit = src->d_btimer;
556 	dst->i_ino_timelimit = src->d_itimer;
557 	dst->i_rt_spc_timelimit = src->d_rtbtimer;
558 	dst->i_ino_warnlimit = src->d_iwarns;
559 	dst->i_spc_warnlimit = src->d_bwarns;
560 	dst->i_rt_spc_warnlimit = src->d_rtbwarns;
561 	if (src->d_fieldmask & FS_DQ_BWARNS)
562 		dst->i_fieldmask |= QC_SPC_WARNS;
563 	if (src->d_fieldmask & FS_DQ_IWARNS)
564 		dst->i_fieldmask |= QC_INO_WARNS;
565 	if (src->d_fieldmask & FS_DQ_RTBWARNS)
566 		dst->i_fieldmask |= QC_RT_SPC_WARNS;
567 	if (src->d_fieldmask & FS_DQ_BTIMER)
568 		dst->i_fieldmask |= QC_SPC_TIMER;
569 	if (src->d_fieldmask & FS_DQ_ITIMER)
570 		dst->i_fieldmask |= QC_INO_TIMER;
571 	if (src->d_fieldmask & FS_DQ_RTBTIMER)
572 		dst->i_fieldmask |= QC_RT_SPC_TIMER;
573 }
574 
575 static int quota_setxquota(struct super_block *sb, int type, qid_t id,
576 			   void __user *addr)
577 {
578 	struct fs_disk_quota fdq;
579 	struct qc_dqblk qdq;
580 	struct kqid qid;
581 
582 	if (copy_from_user(&fdq, addr, sizeof(fdq)))
583 		return -EFAULT;
584 	if (!sb->s_qcop->set_dqblk)
585 		return -ENOSYS;
586 	qid = make_kqid(current_user_ns(), type, id);
587 	if (!qid_has_mapping(sb->s_user_ns, qid))
588 		return -EINVAL;
589 	/* Are we actually setting timer / warning limits for all users? */
590 	if (from_kqid(sb->s_user_ns, qid) == 0 &&
591 	    fdq.d_fieldmask & (FS_DQ_WARNS_MASK | FS_DQ_TIMER_MASK)) {
592 		struct qc_info qinfo;
593 		int ret;
594 
595 		if (!sb->s_qcop->set_info)
596 			return -EINVAL;
597 		copy_qcinfo_from_xfs_dqblk(&qinfo, &fdq);
598 		ret = sb->s_qcop->set_info(sb, type, &qinfo);
599 		if (ret)
600 			return ret;
601 		/* These are already done */
602 		fdq.d_fieldmask &= ~(FS_DQ_WARNS_MASK | FS_DQ_TIMER_MASK);
603 	}
604 	copy_from_xfs_dqblk(&qdq, &fdq);
605 	return sb->s_qcop->set_dqblk(sb, qid, &qdq);
606 }
607 
608 static void copy_to_xfs_dqblk(struct fs_disk_quota *dst, struct qc_dqblk *src,
609 			      int type, qid_t id)
610 {
611 	memset(dst, 0, sizeof(*dst));
612 	dst->d_version = FS_DQUOT_VERSION;
613 	dst->d_id = id;
614 	if (type == USRQUOTA)
615 		dst->d_flags = FS_USER_QUOTA;
616 	else if (type == PRJQUOTA)
617 		dst->d_flags = FS_PROJ_QUOTA;
618 	else
619 		dst->d_flags = FS_GROUP_QUOTA;
620 	dst->d_blk_hardlimit = quota_btobb(src->d_spc_hardlimit);
621 	dst->d_blk_softlimit = quota_btobb(src->d_spc_softlimit);
622 	dst->d_ino_hardlimit = src->d_ino_hardlimit;
623 	dst->d_ino_softlimit = src->d_ino_softlimit;
624 	dst->d_bcount = quota_btobb(src->d_space);
625 	dst->d_icount = src->d_ino_count;
626 	dst->d_itimer = src->d_ino_timer;
627 	dst->d_btimer = src->d_spc_timer;
628 	dst->d_iwarns = src->d_ino_warns;
629 	dst->d_bwarns = src->d_spc_warns;
630 	dst->d_rtb_hardlimit = quota_btobb(src->d_rt_spc_hardlimit);
631 	dst->d_rtb_softlimit = quota_btobb(src->d_rt_spc_softlimit);
632 	dst->d_rtbcount = quota_btobb(src->d_rt_space);
633 	dst->d_rtbtimer = src->d_rt_spc_timer;
634 	dst->d_rtbwarns = src->d_rt_spc_warns;
635 }
636 
637 static int quota_getxquota(struct super_block *sb, int type, qid_t id,
638 			   void __user *addr)
639 {
640 	struct fs_disk_quota fdq;
641 	struct qc_dqblk qdq;
642 	struct kqid qid;
643 	int ret;
644 
645 	if (!sb->s_qcop->get_dqblk)
646 		return -ENOSYS;
647 	qid = make_kqid(current_user_ns(), type, id);
648 	if (!qid_has_mapping(sb->s_user_ns, qid))
649 		return -EINVAL;
650 	ret = sb->s_qcop->get_dqblk(sb, qid, &qdq);
651 	if (ret)
652 		return ret;
653 	copy_to_xfs_dqblk(&fdq, &qdq, type, id);
654 	if (copy_to_user(addr, &fdq, sizeof(fdq)))
655 		return -EFAULT;
656 	return ret;
657 }
658 
659 /*
660  * Return quota for next active quota >= this id, if any exists,
661  * otherwise return -ENOENT via ->get_nextdqblk.
662  */
663 static int quota_getnextxquota(struct super_block *sb, int type, qid_t id,
664 			    void __user *addr)
665 {
666 	struct fs_disk_quota fdq;
667 	struct qc_dqblk qdq;
668 	struct kqid qid;
669 	qid_t id_out;
670 	int ret;
671 
672 	if (!sb->s_qcop->get_nextdqblk)
673 		return -ENOSYS;
674 	qid = make_kqid(current_user_ns(), type, id);
675 	if (!qid_has_mapping(sb->s_user_ns, qid))
676 		return -EINVAL;
677 	ret = sb->s_qcop->get_nextdqblk(sb, &qid, &qdq);
678 	if (ret)
679 		return ret;
680 	id_out = from_kqid(current_user_ns(), qid);
681 	copy_to_xfs_dqblk(&fdq, &qdq, type, id_out);
682 	if (copy_to_user(addr, &fdq, sizeof(fdq)))
683 		return -EFAULT;
684 	return ret;
685 }
686 
687 static int quota_rmxquota(struct super_block *sb, void __user *addr)
688 {
689 	__u32 flags;
690 
691 	if (copy_from_user(&flags, addr, sizeof(flags)))
692 		return -EFAULT;
693 	if (!sb->s_qcop->rm_xquota)
694 		return -ENOSYS;
695 	return sb->s_qcop->rm_xquota(sb, flags);
696 }
697 
698 /* Copy parameters and call proper function */
699 static int do_quotactl(struct super_block *sb, int type, int cmd, qid_t id,
700 		       void __user *addr, const struct path *path)
701 {
702 	int ret;
703 
704 	if (type >= (XQM_COMMAND(cmd) ? XQM_MAXQUOTAS : MAXQUOTAS))
705 		return -EINVAL;
706 	/*
707 	 * Quota not supported on this fs? Check this before s_quota_types
708 	 * since they needn't be set if quota is not supported at all.
709 	 */
710 	if (!sb->s_qcop)
711 		return -ENOSYS;
712 	if (!(sb->s_quota_types & (1 << type)))
713 		return -EINVAL;
714 
715 	ret = check_quotactl_permission(sb, type, cmd, id);
716 	if (ret < 0)
717 		return ret;
718 
719 	switch (cmd) {
720 	case Q_QUOTAON:
721 		return quota_quotaon(sb, type, id, path);
722 	case Q_QUOTAOFF:
723 		return quota_quotaoff(sb, type);
724 	case Q_GETFMT:
725 		return quota_getfmt(sb, type, addr);
726 	case Q_GETINFO:
727 		return quota_getinfo(sb, type, addr);
728 	case Q_SETINFO:
729 		return quota_setinfo(sb, type, addr);
730 	case Q_GETQUOTA:
731 		return quota_getquota(sb, type, id, addr);
732 	case Q_GETNEXTQUOTA:
733 		return quota_getnextquota(sb, type, id, addr);
734 	case Q_SETQUOTA:
735 		return quota_setquota(sb, type, id, addr);
736 	case Q_SYNC:
737 		if (!sb->s_qcop->quota_sync)
738 			return -ENOSYS;
739 		return sb->s_qcop->quota_sync(sb, type);
740 	case Q_XQUOTAON:
741 		return quota_enable(sb, addr);
742 	case Q_XQUOTAOFF:
743 		return quota_disable(sb, addr);
744 	case Q_XQUOTARM:
745 		return quota_rmxquota(sb, addr);
746 	case Q_XGETQSTAT:
747 		return quota_getxstate(sb, addr);
748 	case Q_XGETQSTATV:
749 		return quota_getxstatev(sb, addr);
750 	case Q_XSETQLIM:
751 		return quota_setxquota(sb, type, id, addr);
752 	case Q_XGETQUOTA:
753 		return quota_getxquota(sb, type, id, addr);
754 	case Q_XGETNEXTQUOTA:
755 		return quota_getnextxquota(sb, type, id, addr);
756 	case Q_XQUOTASYNC:
757 		if (sb_rdonly(sb))
758 			return -EROFS;
759 		/* XFS quotas are fully coherent now, making this call a noop */
760 		return 0;
761 	default:
762 		return -EINVAL;
763 	}
764 }
765 
766 #ifdef CONFIG_BLOCK
767 
768 /* Return 1 if 'cmd' will block on frozen filesystem */
769 static int quotactl_cmd_write(int cmd)
770 {
771 	/*
772 	 * We cannot allow Q_GETQUOTA and Q_GETNEXTQUOTA without write access
773 	 * as dquot_acquire() may allocate space for new structure and OCFS2
774 	 * needs to increment on-disk use count.
775 	 */
776 	switch (cmd) {
777 	case Q_GETFMT:
778 	case Q_GETINFO:
779 	case Q_SYNC:
780 	case Q_XGETQSTAT:
781 	case Q_XGETQSTATV:
782 	case Q_XGETQUOTA:
783 	case Q_XGETNEXTQUOTA:
784 	case Q_XQUOTASYNC:
785 		return 0;
786 	}
787 	return 1;
788 }
789 #endif /* CONFIG_BLOCK */
790 
791 /* Return true if quotactl command is manipulating quota on/off state */
792 static bool quotactl_cmd_onoff(int cmd)
793 {
794 	return (cmd == Q_QUOTAON) || (cmd == Q_QUOTAOFF);
795 }
796 
797 /*
798  * look up a superblock on which quota ops will be performed
799  * - use the name of a block device to find the superblock thereon
800  */
801 static struct super_block *quotactl_block(const char __user *special, int cmd)
802 {
803 #ifdef CONFIG_BLOCK
804 	struct block_device *bdev;
805 	struct super_block *sb;
806 	struct filename *tmp = getname(special);
807 
808 	if (IS_ERR(tmp))
809 		return ERR_CAST(tmp);
810 	bdev = lookup_bdev(tmp->name);
811 	putname(tmp);
812 	if (IS_ERR(bdev))
813 		return ERR_CAST(bdev);
814 	if (quotactl_cmd_onoff(cmd))
815 		sb = get_super_exclusive_thawed(bdev);
816 	else if (quotactl_cmd_write(cmd))
817 		sb = get_super_thawed(bdev);
818 	else
819 		sb = get_super(bdev);
820 	bdput(bdev);
821 	if (!sb)
822 		return ERR_PTR(-ENODEV);
823 
824 	return sb;
825 #else
826 	return ERR_PTR(-ENODEV);
827 #endif
828 }
829 
830 /*
831  * This is the system call interface. This communicates with
832  * the user-level programs. Currently this only supports diskquota
833  * calls. Maybe we need to add the process quotas etc. in the future,
834  * but we probably should use rlimits for that.
835  */
836 int kernel_quotactl(unsigned int cmd, const char __user *special,
837 		    qid_t id, void __user *addr)
838 {
839 	uint cmds, type;
840 	struct super_block *sb = NULL;
841 	struct path path, *pathp = NULL;
842 	int ret;
843 
844 	cmds = cmd >> SUBCMDSHIFT;
845 	type = cmd & SUBCMDMASK;
846 
847 	/*
848 	 * As a special case Q_SYNC can be called without a specific device.
849 	 * It will iterate all superblocks that have quota enabled and call
850 	 * the sync action on each of them.
851 	 */
852 	if (!special) {
853 		if (cmds == Q_SYNC)
854 			return quota_sync_all(type);
855 		return -ENODEV;
856 	}
857 
858 	/*
859 	 * Path for quotaon has to be resolved before grabbing superblock
860 	 * because that gets s_umount sem which is also possibly needed by path
861 	 * resolution (think about autofs) and thus deadlocks could arise.
862 	 */
863 	if (cmds == Q_QUOTAON) {
864 		ret = user_path_at(AT_FDCWD, addr, LOOKUP_FOLLOW|LOOKUP_AUTOMOUNT, &path);
865 		if (ret)
866 			pathp = ERR_PTR(ret);
867 		else
868 			pathp = &path;
869 	}
870 
871 	sb = quotactl_block(special, cmds);
872 	if (IS_ERR(sb)) {
873 		ret = PTR_ERR(sb);
874 		goto out;
875 	}
876 
877 	ret = do_quotactl(sb, type, cmds, id, addr, pathp);
878 
879 	if (!quotactl_cmd_onoff(cmds))
880 		drop_super(sb);
881 	else
882 		drop_super_exclusive(sb);
883 out:
884 	if (pathp && !IS_ERR(pathp))
885 		path_put(pathp);
886 	return ret;
887 }
888 
889 SYSCALL_DEFINE4(quotactl, unsigned int, cmd, const char __user *, special,
890 		qid_t, id, void __user *, addr)
891 {
892 	return kernel_quotactl(cmd, special, id, addr);
893 }
894