xref: /openbmc/linux/fs/quota/quota.c (revision 5e012745)
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 #include <linux/nospec.h>
22 
23 static int check_quotactl_permission(struct super_block *sb, int type, int cmd,
24 				     qid_t id)
25 {
26 	switch (cmd) {
27 	/* these commands do not require any special privilegues */
28 	case Q_GETFMT:
29 	case Q_SYNC:
30 	case Q_GETINFO:
31 	case Q_XGETQSTAT:
32 	case Q_XGETQSTATV:
33 	case Q_XQUOTASYNC:
34 		break;
35 	/* allow to query information for dquots we "own" */
36 	case Q_GETQUOTA:
37 	case Q_XGETQUOTA:
38 		if ((type == USRQUOTA && uid_eq(current_euid(), make_kuid(current_user_ns(), id))) ||
39 		    (type == GRPQUOTA && in_egroup_p(make_kgid(current_user_ns(), id))))
40 			break;
41 		/*FALLTHROUGH*/
42 	default:
43 		if (!capable(CAP_SYS_ADMIN))
44 			return -EPERM;
45 	}
46 
47 	return security_quotactl(cmd, type, id, sb);
48 }
49 
50 static void quota_sync_one(struct super_block *sb, void *arg)
51 {
52 	int type = *(int *)arg;
53 
54 	if (sb->s_qcop && sb->s_qcop->quota_sync &&
55 	    (sb->s_quota_types & (1 << type)))
56 		sb->s_qcop->quota_sync(sb, type);
57 }
58 
59 static int quota_sync_all(int type)
60 {
61 	int ret;
62 
63 	if (type >= MAXQUOTAS)
64 		return -EINVAL;
65 	ret = security_quotactl(Q_SYNC, type, 0, NULL);
66 	if (!ret)
67 		iterate_supers(quota_sync_one, &type);
68 	return ret;
69 }
70 
71 unsigned int qtype_enforce_flag(int type)
72 {
73 	switch (type) {
74 	case USRQUOTA:
75 		return FS_QUOTA_UDQ_ENFD;
76 	case GRPQUOTA:
77 		return FS_QUOTA_GDQ_ENFD;
78 	case PRJQUOTA:
79 		return FS_QUOTA_PDQ_ENFD;
80 	}
81 	return 0;
82 }
83 
84 static int quota_quotaon(struct super_block *sb, int type, qid_t id,
85 		         const struct path *path)
86 {
87 	if (!sb->s_qcop->quota_on && !sb->s_qcop->quota_enable)
88 		return -ENOSYS;
89 	if (sb->s_qcop->quota_enable)
90 		return sb->s_qcop->quota_enable(sb, qtype_enforce_flag(type));
91 	if (IS_ERR(path))
92 		return PTR_ERR(path);
93 	return sb->s_qcop->quota_on(sb, type, id, path);
94 }
95 
96 static int quota_quotaoff(struct super_block *sb, int type)
97 {
98 	if (!sb->s_qcop->quota_off && !sb->s_qcop->quota_disable)
99 		return -ENOSYS;
100 	if (sb->s_qcop->quota_disable)
101 		return sb->s_qcop->quota_disable(sb, qtype_enforce_flag(type));
102 	return sb->s_qcop->quota_off(sb, type);
103 }
104 
105 static int quota_getfmt(struct super_block *sb, int type, void __user *addr)
106 {
107 	__u32 fmt;
108 
109 	if (!sb_has_quota_active(sb, type))
110 		return -ESRCH;
111 	fmt = sb_dqopt(sb)->info[type].dqi_format->qf_fmt_id;
112 	if (copy_to_user(addr, &fmt, sizeof(fmt)))
113 		return -EFAULT;
114 	return 0;
115 }
116 
117 static int quota_getinfo(struct super_block *sb, int type, void __user *addr)
118 {
119 	struct qc_state state;
120 	struct qc_type_state *tstate;
121 	struct if_dqinfo uinfo;
122 	int ret;
123 
124 	if (!sb->s_qcop->get_state)
125 		return -ENOSYS;
126 	ret = sb->s_qcop->get_state(sb, &state);
127 	if (ret)
128 		return ret;
129 	tstate = state.s_state + type;
130 	if (!(tstate->flags & QCI_ACCT_ENABLED))
131 		return -ESRCH;
132 	memset(&uinfo, 0, sizeof(uinfo));
133 	uinfo.dqi_bgrace = tstate->spc_timelimit;
134 	uinfo.dqi_igrace = tstate->ino_timelimit;
135 	if (tstate->flags & QCI_SYSFILE)
136 		uinfo.dqi_flags |= DQF_SYS_FILE;
137 	if (tstate->flags & QCI_ROOT_SQUASH)
138 		uinfo.dqi_flags |= DQF_ROOT_SQUASH;
139 	uinfo.dqi_valid = IIF_ALL;
140 	if (copy_to_user(addr, &uinfo, sizeof(uinfo)))
141 		return -EFAULT;
142 	return 0;
143 }
144 
145 static int quota_setinfo(struct super_block *sb, int type, void __user *addr)
146 {
147 	struct if_dqinfo info;
148 	struct qc_info qinfo;
149 
150 	if (copy_from_user(&info, addr, sizeof(info)))
151 		return -EFAULT;
152 	if (!sb->s_qcop->set_info)
153 		return -ENOSYS;
154 	if (info.dqi_valid & ~(IIF_FLAGS | IIF_BGRACE | IIF_IGRACE))
155 		return -EINVAL;
156 	memset(&qinfo, 0, sizeof(qinfo));
157 	if (info.dqi_valid & IIF_FLAGS) {
158 		if (info.dqi_flags & ~DQF_SETINFO_MASK)
159 			return -EINVAL;
160 		if (info.dqi_flags & DQF_ROOT_SQUASH)
161 			qinfo.i_flags |= QCI_ROOT_SQUASH;
162 		qinfo.i_fieldmask |= QC_FLAGS;
163 	}
164 	if (info.dqi_valid & IIF_BGRACE) {
165 		qinfo.i_spc_timelimit = info.dqi_bgrace;
166 		qinfo.i_fieldmask |= QC_SPC_TIMER;
167 	}
168 	if (info.dqi_valid & IIF_IGRACE) {
169 		qinfo.i_ino_timelimit = info.dqi_igrace;
170 		qinfo.i_fieldmask |= QC_INO_TIMER;
171 	}
172 	return sb->s_qcop->set_info(sb, type, &qinfo);
173 }
174 
175 static inline qsize_t qbtos(qsize_t blocks)
176 {
177 	return blocks << QIF_DQBLKSIZE_BITS;
178 }
179 
180 static inline qsize_t stoqb(qsize_t space)
181 {
182 	return (space + QIF_DQBLKSIZE - 1) >> QIF_DQBLKSIZE_BITS;
183 }
184 
185 static void copy_to_if_dqblk(struct if_dqblk *dst, struct qc_dqblk *src)
186 {
187 	memset(dst, 0, sizeof(*dst));
188 	dst->dqb_bhardlimit = stoqb(src->d_spc_hardlimit);
189 	dst->dqb_bsoftlimit = stoqb(src->d_spc_softlimit);
190 	dst->dqb_curspace = src->d_space;
191 	dst->dqb_ihardlimit = src->d_ino_hardlimit;
192 	dst->dqb_isoftlimit = src->d_ino_softlimit;
193 	dst->dqb_curinodes = src->d_ino_count;
194 	dst->dqb_btime = src->d_spc_timer;
195 	dst->dqb_itime = src->d_ino_timer;
196 	dst->dqb_valid = QIF_ALL;
197 }
198 
199 static int quota_getquota(struct super_block *sb, int type, qid_t id,
200 			  void __user *addr)
201 {
202 	struct kqid qid;
203 	struct qc_dqblk fdq;
204 	struct if_dqblk idq;
205 	int ret;
206 
207 	if (!sb->s_qcop->get_dqblk)
208 		return -ENOSYS;
209 	qid = make_kqid(current_user_ns(), type, id);
210 	if (!qid_has_mapping(sb->s_user_ns, qid))
211 		return -EINVAL;
212 	ret = sb->s_qcop->get_dqblk(sb, qid, &fdq);
213 	if (ret)
214 		return ret;
215 	copy_to_if_dqblk(&idq, &fdq);
216 	if (copy_to_user(addr, &idq, sizeof(idq)))
217 		return -EFAULT;
218 	return 0;
219 }
220 
221 /*
222  * Return quota for next active quota >= this id, if any exists,
223  * otherwise return -ENOENT via ->get_nextdqblk
224  */
225 static int quota_getnextquota(struct super_block *sb, int type, qid_t id,
226 			  void __user *addr)
227 {
228 	struct kqid qid;
229 	struct qc_dqblk fdq;
230 	struct if_nextdqblk idq;
231 	int ret;
232 
233 	if (!sb->s_qcop->get_nextdqblk)
234 		return -ENOSYS;
235 	qid = make_kqid(current_user_ns(), type, id);
236 	if (!qid_has_mapping(sb->s_user_ns, qid))
237 		return -EINVAL;
238 	ret = sb->s_qcop->get_nextdqblk(sb, &qid, &fdq);
239 	if (ret)
240 		return ret;
241 	/* struct if_nextdqblk is a superset of struct if_dqblk */
242 	copy_to_if_dqblk((struct if_dqblk *)&idq, &fdq);
243 	idq.dqb_id = from_kqid(current_user_ns(), qid);
244 	if (copy_to_user(addr, &idq, sizeof(idq)))
245 		return -EFAULT;
246 	return 0;
247 }
248 
249 static void copy_from_if_dqblk(struct qc_dqblk *dst, struct if_dqblk *src)
250 {
251 	dst->d_spc_hardlimit = qbtos(src->dqb_bhardlimit);
252 	dst->d_spc_softlimit = qbtos(src->dqb_bsoftlimit);
253 	dst->d_space = src->dqb_curspace;
254 	dst->d_ino_hardlimit = src->dqb_ihardlimit;
255 	dst->d_ino_softlimit = src->dqb_isoftlimit;
256 	dst->d_ino_count = src->dqb_curinodes;
257 	dst->d_spc_timer = src->dqb_btime;
258 	dst->d_ino_timer = src->dqb_itime;
259 
260 	dst->d_fieldmask = 0;
261 	if (src->dqb_valid & QIF_BLIMITS)
262 		dst->d_fieldmask |= QC_SPC_SOFT | QC_SPC_HARD;
263 	if (src->dqb_valid & QIF_SPACE)
264 		dst->d_fieldmask |= QC_SPACE;
265 	if (src->dqb_valid & QIF_ILIMITS)
266 		dst->d_fieldmask |= QC_INO_SOFT | QC_INO_HARD;
267 	if (src->dqb_valid & QIF_INODES)
268 		dst->d_fieldmask |= QC_INO_COUNT;
269 	if (src->dqb_valid & QIF_BTIME)
270 		dst->d_fieldmask |= QC_SPC_TIMER;
271 	if (src->dqb_valid & QIF_ITIME)
272 		dst->d_fieldmask |= QC_INO_TIMER;
273 }
274 
275 static int quota_setquota(struct super_block *sb, int type, qid_t id,
276 			  void __user *addr)
277 {
278 	struct qc_dqblk fdq;
279 	struct if_dqblk idq;
280 	struct kqid qid;
281 
282 	if (copy_from_user(&idq, addr, sizeof(idq)))
283 		return -EFAULT;
284 	if (!sb->s_qcop->set_dqblk)
285 		return -ENOSYS;
286 	qid = make_kqid(current_user_ns(), type, id);
287 	if (!qid_has_mapping(sb->s_user_ns, qid))
288 		return -EINVAL;
289 	copy_from_if_dqblk(&fdq, &idq);
290 	return sb->s_qcop->set_dqblk(sb, qid, &fdq);
291 }
292 
293 static int quota_enable(struct super_block *sb, void __user *addr)
294 {
295 	__u32 flags;
296 
297 	if (copy_from_user(&flags, addr, sizeof(flags)))
298 		return -EFAULT;
299 	if (!sb->s_qcop->quota_enable)
300 		return -ENOSYS;
301 	return sb->s_qcop->quota_enable(sb, flags);
302 }
303 
304 static int quota_disable(struct super_block *sb, void __user *addr)
305 {
306 	__u32 flags;
307 
308 	if (copy_from_user(&flags, addr, sizeof(flags)))
309 		return -EFAULT;
310 	if (!sb->s_qcop->quota_disable)
311 		return -ENOSYS;
312 	return sb->s_qcop->quota_disable(sb, flags);
313 }
314 
315 static int quota_state_to_flags(struct qc_state *state)
316 {
317 	int flags = 0;
318 
319 	if (state->s_state[USRQUOTA].flags & QCI_ACCT_ENABLED)
320 		flags |= FS_QUOTA_UDQ_ACCT;
321 	if (state->s_state[USRQUOTA].flags & QCI_LIMITS_ENFORCED)
322 		flags |= FS_QUOTA_UDQ_ENFD;
323 	if (state->s_state[GRPQUOTA].flags & QCI_ACCT_ENABLED)
324 		flags |= FS_QUOTA_GDQ_ACCT;
325 	if (state->s_state[GRPQUOTA].flags & QCI_LIMITS_ENFORCED)
326 		flags |= FS_QUOTA_GDQ_ENFD;
327 	if (state->s_state[PRJQUOTA].flags & QCI_ACCT_ENABLED)
328 		flags |= FS_QUOTA_PDQ_ACCT;
329 	if (state->s_state[PRJQUOTA].flags & QCI_LIMITS_ENFORCED)
330 		flags |= FS_QUOTA_PDQ_ENFD;
331 	return flags;
332 }
333 
334 static int quota_getstate(struct super_block *sb, int type,
335 			  struct fs_quota_stat *fqs)
336 {
337 	struct qc_state state;
338 	int ret;
339 
340 	memset(&state, 0, sizeof (struct qc_state));
341 	ret = sb->s_qcop->get_state(sb, &state);
342 	if (ret < 0)
343 		return ret;
344 
345 	memset(fqs, 0, sizeof(*fqs));
346 	fqs->qs_version = FS_QSTAT_VERSION;
347 	fqs->qs_flags = quota_state_to_flags(&state);
348 	/* No quota enabled? */
349 	if (!fqs->qs_flags)
350 		return -ENOSYS;
351 	fqs->qs_incoredqs = state.s_incoredqs;
352 
353 	fqs->qs_btimelimit = state.s_state[type].spc_timelimit;
354 	fqs->qs_itimelimit = state.s_state[type].ino_timelimit;
355 	fqs->qs_rtbtimelimit = state.s_state[type].rt_spc_timelimit;
356 	fqs->qs_bwarnlimit = state.s_state[type].spc_warnlimit;
357 	fqs->qs_iwarnlimit = state.s_state[type].ino_warnlimit;
358 
359 	/* Inodes may be allocated even if inactive; copy out if present */
360 	if (state.s_state[USRQUOTA].ino) {
361 		fqs->qs_uquota.qfs_ino = state.s_state[USRQUOTA].ino;
362 		fqs->qs_uquota.qfs_nblks = state.s_state[USRQUOTA].blocks;
363 		fqs->qs_uquota.qfs_nextents = state.s_state[USRQUOTA].nextents;
364 	}
365 	if (state.s_state[GRPQUOTA].ino) {
366 		fqs->qs_gquota.qfs_ino = state.s_state[GRPQUOTA].ino;
367 		fqs->qs_gquota.qfs_nblks = state.s_state[GRPQUOTA].blocks;
368 		fqs->qs_gquota.qfs_nextents = state.s_state[GRPQUOTA].nextents;
369 	}
370 	if (state.s_state[PRJQUOTA].ino) {
371 		/*
372 		 * Q_XGETQSTAT doesn't have room for both group and project
373 		 * quotas.  So, allow the project quota values to be copied out
374 		 * only if there is no group quota information available.
375 		 */
376 		if (!(state.s_state[GRPQUOTA].flags & QCI_ACCT_ENABLED)) {
377 			fqs->qs_gquota.qfs_ino = state.s_state[PRJQUOTA].ino;
378 			fqs->qs_gquota.qfs_nblks =
379 					state.s_state[PRJQUOTA].blocks;
380 			fqs->qs_gquota.qfs_nextents =
381 					state.s_state[PRJQUOTA].nextents;
382 		}
383 	}
384 	return 0;
385 }
386 
387 static int quota_getxstate(struct super_block *sb, int type, void __user *addr)
388 {
389 	struct fs_quota_stat fqs;
390 	int ret;
391 
392 	if (!sb->s_qcop->get_state)
393 		return -ENOSYS;
394 	ret = quota_getstate(sb, type, &fqs);
395 	if (!ret && copy_to_user(addr, &fqs, sizeof(fqs)))
396 		return -EFAULT;
397 	return ret;
398 }
399 
400 static int quota_getstatev(struct super_block *sb, int type,
401 			   struct fs_quota_statv *fqs)
402 {
403 	struct qc_state state;
404 	int ret;
405 
406 	memset(&state, 0, sizeof (struct qc_state));
407 	ret = sb->s_qcop->get_state(sb, &state);
408 	if (ret < 0)
409 		return ret;
410 
411 	memset(fqs, 0, sizeof(*fqs));
412 	fqs->qs_version = FS_QSTAT_VERSION;
413 	fqs->qs_flags = quota_state_to_flags(&state);
414 	/* No quota enabled? */
415 	if (!fqs->qs_flags)
416 		return -ENOSYS;
417 	fqs->qs_incoredqs = state.s_incoredqs;
418 
419 	fqs->qs_btimelimit = state.s_state[type].spc_timelimit;
420 	fqs->qs_itimelimit = state.s_state[type].ino_timelimit;
421 	fqs->qs_rtbtimelimit = state.s_state[type].rt_spc_timelimit;
422 	fqs->qs_bwarnlimit = state.s_state[type].spc_warnlimit;
423 	fqs->qs_iwarnlimit = state.s_state[type].ino_warnlimit;
424 
425 	/* Inodes may be allocated even if inactive; copy out if present */
426 	if (state.s_state[USRQUOTA].ino) {
427 		fqs->qs_uquota.qfs_ino = state.s_state[USRQUOTA].ino;
428 		fqs->qs_uquota.qfs_nblks = state.s_state[USRQUOTA].blocks;
429 		fqs->qs_uquota.qfs_nextents = state.s_state[USRQUOTA].nextents;
430 	}
431 	if (state.s_state[GRPQUOTA].ino) {
432 		fqs->qs_gquota.qfs_ino = state.s_state[GRPQUOTA].ino;
433 		fqs->qs_gquota.qfs_nblks = state.s_state[GRPQUOTA].blocks;
434 		fqs->qs_gquota.qfs_nextents = state.s_state[GRPQUOTA].nextents;
435 	}
436 	if (state.s_state[PRJQUOTA].ino) {
437 		fqs->qs_pquota.qfs_ino = state.s_state[PRJQUOTA].ino;
438 		fqs->qs_pquota.qfs_nblks = state.s_state[PRJQUOTA].blocks;
439 		fqs->qs_pquota.qfs_nextents = state.s_state[PRJQUOTA].nextents;
440 	}
441 	return 0;
442 }
443 
444 static int quota_getxstatev(struct super_block *sb, int type, void __user *addr)
445 {
446 	struct fs_quota_statv fqs;
447 	int ret;
448 
449 	if (!sb->s_qcop->get_state)
450 		return -ENOSYS;
451 
452 	memset(&fqs, 0, sizeof(fqs));
453 	if (copy_from_user(&fqs, addr, 1)) /* Just read qs_version */
454 		return -EFAULT;
455 
456 	/* If this kernel doesn't support user specified version, fail */
457 	switch (fqs.qs_version) {
458 	case FS_QSTATV_VERSION1:
459 		break;
460 	default:
461 		return -EINVAL;
462 	}
463 	ret = quota_getstatev(sb, type, &fqs);
464 	if (!ret && copy_to_user(addr, &fqs, sizeof(fqs)))
465 		return -EFAULT;
466 	return ret;
467 }
468 
469 /*
470  * XFS defines BBTOB and BTOBB macros inside fs/xfs/ and we cannot move them
471  * out of there as xfsprogs rely on definitions being in that header file. So
472  * just define same functions here for quota purposes.
473  */
474 #define XFS_BB_SHIFT 9
475 
476 static inline u64 quota_bbtob(u64 blocks)
477 {
478 	return blocks << XFS_BB_SHIFT;
479 }
480 
481 static inline u64 quota_btobb(u64 bytes)
482 {
483 	return (bytes + (1 << XFS_BB_SHIFT) - 1) >> XFS_BB_SHIFT;
484 }
485 
486 static void copy_from_xfs_dqblk(struct qc_dqblk *dst, struct fs_disk_quota *src)
487 {
488 	dst->d_spc_hardlimit = quota_bbtob(src->d_blk_hardlimit);
489 	dst->d_spc_softlimit = quota_bbtob(src->d_blk_softlimit);
490 	dst->d_ino_hardlimit = src->d_ino_hardlimit;
491 	dst->d_ino_softlimit = src->d_ino_softlimit;
492 	dst->d_space = quota_bbtob(src->d_bcount);
493 	dst->d_ino_count = src->d_icount;
494 	dst->d_ino_timer = src->d_itimer;
495 	dst->d_spc_timer = src->d_btimer;
496 	dst->d_ino_warns = src->d_iwarns;
497 	dst->d_spc_warns = src->d_bwarns;
498 	dst->d_rt_spc_hardlimit = quota_bbtob(src->d_rtb_hardlimit);
499 	dst->d_rt_spc_softlimit = quota_bbtob(src->d_rtb_softlimit);
500 	dst->d_rt_space = quota_bbtob(src->d_rtbcount);
501 	dst->d_rt_spc_timer = src->d_rtbtimer;
502 	dst->d_rt_spc_warns = src->d_rtbwarns;
503 	dst->d_fieldmask = 0;
504 	if (src->d_fieldmask & FS_DQ_ISOFT)
505 		dst->d_fieldmask |= QC_INO_SOFT;
506 	if (src->d_fieldmask & FS_DQ_IHARD)
507 		dst->d_fieldmask |= QC_INO_HARD;
508 	if (src->d_fieldmask & FS_DQ_BSOFT)
509 		dst->d_fieldmask |= QC_SPC_SOFT;
510 	if (src->d_fieldmask & FS_DQ_BHARD)
511 		dst->d_fieldmask |= QC_SPC_HARD;
512 	if (src->d_fieldmask & FS_DQ_RTBSOFT)
513 		dst->d_fieldmask |= QC_RT_SPC_SOFT;
514 	if (src->d_fieldmask & FS_DQ_RTBHARD)
515 		dst->d_fieldmask |= QC_RT_SPC_HARD;
516 	if (src->d_fieldmask & FS_DQ_BTIMER)
517 		dst->d_fieldmask |= QC_SPC_TIMER;
518 	if (src->d_fieldmask & FS_DQ_ITIMER)
519 		dst->d_fieldmask |= QC_INO_TIMER;
520 	if (src->d_fieldmask & FS_DQ_RTBTIMER)
521 		dst->d_fieldmask |= QC_RT_SPC_TIMER;
522 	if (src->d_fieldmask & FS_DQ_BWARNS)
523 		dst->d_fieldmask |= QC_SPC_WARNS;
524 	if (src->d_fieldmask & FS_DQ_IWARNS)
525 		dst->d_fieldmask |= QC_INO_WARNS;
526 	if (src->d_fieldmask & FS_DQ_RTBWARNS)
527 		dst->d_fieldmask |= QC_RT_SPC_WARNS;
528 	if (src->d_fieldmask & FS_DQ_BCOUNT)
529 		dst->d_fieldmask |= QC_SPACE;
530 	if (src->d_fieldmask & FS_DQ_ICOUNT)
531 		dst->d_fieldmask |= QC_INO_COUNT;
532 	if (src->d_fieldmask & FS_DQ_RTBCOUNT)
533 		dst->d_fieldmask |= QC_RT_SPACE;
534 }
535 
536 static void copy_qcinfo_from_xfs_dqblk(struct qc_info *dst,
537 				       struct fs_disk_quota *src)
538 {
539 	memset(dst, 0, sizeof(*dst));
540 	dst->i_spc_timelimit = src->d_btimer;
541 	dst->i_ino_timelimit = src->d_itimer;
542 	dst->i_rt_spc_timelimit = src->d_rtbtimer;
543 	dst->i_ino_warnlimit = src->d_iwarns;
544 	dst->i_spc_warnlimit = src->d_bwarns;
545 	dst->i_rt_spc_warnlimit = src->d_rtbwarns;
546 	if (src->d_fieldmask & FS_DQ_BWARNS)
547 		dst->i_fieldmask |= QC_SPC_WARNS;
548 	if (src->d_fieldmask & FS_DQ_IWARNS)
549 		dst->i_fieldmask |= QC_INO_WARNS;
550 	if (src->d_fieldmask & FS_DQ_RTBWARNS)
551 		dst->i_fieldmask |= QC_RT_SPC_WARNS;
552 	if (src->d_fieldmask & FS_DQ_BTIMER)
553 		dst->i_fieldmask |= QC_SPC_TIMER;
554 	if (src->d_fieldmask & FS_DQ_ITIMER)
555 		dst->i_fieldmask |= QC_INO_TIMER;
556 	if (src->d_fieldmask & FS_DQ_RTBTIMER)
557 		dst->i_fieldmask |= QC_RT_SPC_TIMER;
558 }
559 
560 static int quota_setxquota(struct super_block *sb, int type, qid_t id,
561 			   void __user *addr)
562 {
563 	struct fs_disk_quota fdq;
564 	struct qc_dqblk qdq;
565 	struct kqid qid;
566 
567 	if (copy_from_user(&fdq, addr, sizeof(fdq)))
568 		return -EFAULT;
569 	if (!sb->s_qcop->set_dqblk)
570 		return -ENOSYS;
571 	qid = make_kqid(current_user_ns(), type, id);
572 	if (!qid_has_mapping(sb->s_user_ns, qid))
573 		return -EINVAL;
574 	/* Are we actually setting timer / warning limits for all users? */
575 	if (from_kqid(sb->s_user_ns, qid) == 0 &&
576 	    fdq.d_fieldmask & (FS_DQ_WARNS_MASK | FS_DQ_TIMER_MASK)) {
577 		struct qc_info qinfo;
578 		int ret;
579 
580 		if (!sb->s_qcop->set_info)
581 			return -EINVAL;
582 		copy_qcinfo_from_xfs_dqblk(&qinfo, &fdq);
583 		ret = sb->s_qcop->set_info(sb, type, &qinfo);
584 		if (ret)
585 			return ret;
586 		/* These are already done */
587 		fdq.d_fieldmask &= ~(FS_DQ_WARNS_MASK | FS_DQ_TIMER_MASK);
588 	}
589 	copy_from_xfs_dqblk(&qdq, &fdq);
590 	return sb->s_qcop->set_dqblk(sb, qid, &qdq);
591 }
592 
593 static void copy_to_xfs_dqblk(struct fs_disk_quota *dst, struct qc_dqblk *src,
594 			      int type, qid_t id)
595 {
596 	memset(dst, 0, sizeof(*dst));
597 	dst->d_version = FS_DQUOT_VERSION;
598 	dst->d_id = id;
599 	if (type == USRQUOTA)
600 		dst->d_flags = FS_USER_QUOTA;
601 	else if (type == PRJQUOTA)
602 		dst->d_flags = FS_PROJ_QUOTA;
603 	else
604 		dst->d_flags = FS_GROUP_QUOTA;
605 	dst->d_blk_hardlimit = quota_btobb(src->d_spc_hardlimit);
606 	dst->d_blk_softlimit = quota_btobb(src->d_spc_softlimit);
607 	dst->d_ino_hardlimit = src->d_ino_hardlimit;
608 	dst->d_ino_softlimit = src->d_ino_softlimit;
609 	dst->d_bcount = quota_btobb(src->d_space);
610 	dst->d_icount = src->d_ino_count;
611 	dst->d_itimer = src->d_ino_timer;
612 	dst->d_btimer = src->d_spc_timer;
613 	dst->d_iwarns = src->d_ino_warns;
614 	dst->d_bwarns = src->d_spc_warns;
615 	dst->d_rtb_hardlimit = quota_btobb(src->d_rt_spc_hardlimit);
616 	dst->d_rtb_softlimit = quota_btobb(src->d_rt_spc_softlimit);
617 	dst->d_rtbcount = quota_btobb(src->d_rt_space);
618 	dst->d_rtbtimer = src->d_rt_spc_timer;
619 	dst->d_rtbwarns = src->d_rt_spc_warns;
620 }
621 
622 static int quota_getxquota(struct super_block *sb, int type, qid_t id,
623 			   void __user *addr)
624 {
625 	struct fs_disk_quota fdq;
626 	struct qc_dqblk qdq;
627 	struct kqid qid;
628 	int ret;
629 
630 	if (!sb->s_qcop->get_dqblk)
631 		return -ENOSYS;
632 	qid = make_kqid(current_user_ns(), type, id);
633 	if (!qid_has_mapping(sb->s_user_ns, qid))
634 		return -EINVAL;
635 	ret = sb->s_qcop->get_dqblk(sb, qid, &qdq);
636 	if (ret)
637 		return ret;
638 	copy_to_xfs_dqblk(&fdq, &qdq, type, id);
639 	if (copy_to_user(addr, &fdq, sizeof(fdq)))
640 		return -EFAULT;
641 	return ret;
642 }
643 
644 /*
645  * Return quota for next active quota >= this id, if any exists,
646  * otherwise return -ENOENT via ->get_nextdqblk.
647  */
648 static int quota_getnextxquota(struct super_block *sb, int type, qid_t id,
649 			    void __user *addr)
650 {
651 	struct fs_disk_quota fdq;
652 	struct qc_dqblk qdq;
653 	struct kqid qid;
654 	qid_t id_out;
655 	int ret;
656 
657 	if (!sb->s_qcop->get_nextdqblk)
658 		return -ENOSYS;
659 	qid = make_kqid(current_user_ns(), type, id);
660 	if (!qid_has_mapping(sb->s_user_ns, qid))
661 		return -EINVAL;
662 	ret = sb->s_qcop->get_nextdqblk(sb, &qid, &qdq);
663 	if (ret)
664 		return ret;
665 	id_out = from_kqid(current_user_ns(), qid);
666 	copy_to_xfs_dqblk(&fdq, &qdq, type, id_out);
667 	if (copy_to_user(addr, &fdq, sizeof(fdq)))
668 		return -EFAULT;
669 	return ret;
670 }
671 
672 static int quota_rmxquota(struct super_block *sb, void __user *addr)
673 {
674 	__u32 flags;
675 
676 	if (copy_from_user(&flags, addr, sizeof(flags)))
677 		return -EFAULT;
678 	if (!sb->s_qcop->rm_xquota)
679 		return -ENOSYS;
680 	return sb->s_qcop->rm_xquota(sb, flags);
681 }
682 
683 /* Copy parameters and call proper function */
684 static int do_quotactl(struct super_block *sb, int type, int cmd, qid_t id,
685 		       void __user *addr, const struct path *path)
686 {
687 	int ret;
688 
689 	if (type >= MAXQUOTAS)
690 		return -EINVAL;
691 	type = array_index_nospec(type, MAXQUOTAS);
692 	/*
693 	 * Quota not supported on this fs? Check this before s_quota_types
694 	 * since they needn't be set if quota is not supported at all.
695 	 */
696 	if (!sb->s_qcop)
697 		return -ENOSYS;
698 	if (!(sb->s_quota_types & (1 << type)))
699 		return -EINVAL;
700 
701 	ret = check_quotactl_permission(sb, type, cmd, id);
702 	if (ret < 0)
703 		return ret;
704 
705 	switch (cmd) {
706 	case Q_QUOTAON:
707 		return quota_quotaon(sb, type, id, path);
708 	case Q_QUOTAOFF:
709 		return quota_quotaoff(sb, type);
710 	case Q_GETFMT:
711 		return quota_getfmt(sb, type, addr);
712 	case Q_GETINFO:
713 		return quota_getinfo(sb, type, addr);
714 	case Q_SETINFO:
715 		return quota_setinfo(sb, type, addr);
716 	case Q_GETQUOTA:
717 		return quota_getquota(sb, type, id, addr);
718 	case Q_GETNEXTQUOTA:
719 		return quota_getnextquota(sb, type, id, addr);
720 	case Q_SETQUOTA:
721 		return quota_setquota(sb, type, id, addr);
722 	case Q_SYNC:
723 		if (!sb->s_qcop->quota_sync)
724 			return -ENOSYS;
725 		return sb->s_qcop->quota_sync(sb, type);
726 	case Q_XQUOTAON:
727 		return quota_enable(sb, addr);
728 	case Q_XQUOTAOFF:
729 		return quota_disable(sb, addr);
730 	case Q_XQUOTARM:
731 		return quota_rmxquota(sb, addr);
732 	case Q_XGETQSTAT:
733 		return quota_getxstate(sb, type, addr);
734 	case Q_XGETQSTATV:
735 		return quota_getxstatev(sb, type, addr);
736 	case Q_XSETQLIM:
737 		return quota_setxquota(sb, type, id, addr);
738 	case Q_XGETQUOTA:
739 		return quota_getxquota(sb, type, id, addr);
740 	case Q_XGETNEXTQUOTA:
741 		return quota_getnextxquota(sb, type, id, addr);
742 	case Q_XQUOTASYNC:
743 		if (sb_rdonly(sb))
744 			return -EROFS;
745 		/* XFS quotas are fully coherent now, making this call a noop */
746 		return 0;
747 	default:
748 		return -EINVAL;
749 	}
750 }
751 
752 #ifdef CONFIG_BLOCK
753 
754 /* Return 1 if 'cmd' will block on frozen filesystem */
755 static int quotactl_cmd_write(int cmd)
756 {
757 	/*
758 	 * We cannot allow Q_GETQUOTA and Q_GETNEXTQUOTA without write access
759 	 * as dquot_acquire() may allocate space for new structure and OCFS2
760 	 * needs to increment on-disk use count.
761 	 */
762 	switch (cmd) {
763 	case Q_GETFMT:
764 	case Q_GETINFO:
765 	case Q_SYNC:
766 	case Q_XGETQSTAT:
767 	case Q_XGETQSTATV:
768 	case Q_XGETQUOTA:
769 	case Q_XGETNEXTQUOTA:
770 	case Q_XQUOTASYNC:
771 		return 0;
772 	}
773 	return 1;
774 }
775 #endif /* CONFIG_BLOCK */
776 
777 /* Return true if quotactl command is manipulating quota on/off state */
778 static bool quotactl_cmd_onoff(int cmd)
779 {
780 	return (cmd == Q_QUOTAON) || (cmd == Q_QUOTAOFF) ||
781 		 (cmd == Q_XQUOTAON) || (cmd == Q_XQUOTAOFF);
782 }
783 
784 /*
785  * look up a superblock on which quota ops will be performed
786  * - use the name of a block device to find the superblock thereon
787  */
788 static struct super_block *quotactl_block(const char __user *special, int cmd)
789 {
790 #ifdef CONFIG_BLOCK
791 	struct block_device *bdev;
792 	struct super_block *sb;
793 	struct filename *tmp = getname(special);
794 
795 	if (IS_ERR(tmp))
796 		return ERR_CAST(tmp);
797 	bdev = lookup_bdev(tmp->name);
798 	putname(tmp);
799 	if (IS_ERR(bdev))
800 		return ERR_CAST(bdev);
801 	if (quotactl_cmd_onoff(cmd))
802 		sb = get_super_exclusive_thawed(bdev);
803 	else if (quotactl_cmd_write(cmd))
804 		sb = get_super_thawed(bdev);
805 	else
806 		sb = get_super(bdev);
807 	bdput(bdev);
808 	if (!sb)
809 		return ERR_PTR(-ENODEV);
810 
811 	return sb;
812 #else
813 	return ERR_PTR(-ENODEV);
814 #endif
815 }
816 
817 /*
818  * This is the system call interface. This communicates with
819  * the user-level programs. Currently this only supports diskquota
820  * calls. Maybe we need to add the process quotas etc. in the future,
821  * but we probably should use rlimits for that.
822  */
823 int kernel_quotactl(unsigned int cmd, const char __user *special,
824 		    qid_t id, void __user *addr)
825 {
826 	uint cmds, type;
827 	struct super_block *sb = NULL;
828 	struct path path, *pathp = NULL;
829 	int ret;
830 
831 	cmds = cmd >> SUBCMDSHIFT;
832 	type = cmd & SUBCMDMASK;
833 
834 	/*
835 	 * As a special case Q_SYNC can be called without a specific device.
836 	 * It will iterate all superblocks that have quota enabled and call
837 	 * the sync action on each of them.
838 	 */
839 	if (!special) {
840 		if (cmds == Q_SYNC)
841 			return quota_sync_all(type);
842 		return -ENODEV;
843 	}
844 
845 	/*
846 	 * Path for quotaon has to be resolved before grabbing superblock
847 	 * because that gets s_umount sem which is also possibly needed by path
848 	 * resolution (think about autofs) and thus deadlocks could arise.
849 	 */
850 	if (cmds == Q_QUOTAON) {
851 		ret = user_path_at(AT_FDCWD, addr, LOOKUP_FOLLOW|LOOKUP_AUTOMOUNT, &path);
852 		if (ret)
853 			pathp = ERR_PTR(ret);
854 		else
855 			pathp = &path;
856 	}
857 
858 	sb = quotactl_block(special, cmds);
859 	if (IS_ERR(sb)) {
860 		ret = PTR_ERR(sb);
861 		goto out;
862 	}
863 
864 	ret = do_quotactl(sb, type, cmds, id, addr, pathp);
865 
866 	if (!quotactl_cmd_onoff(cmds))
867 		drop_super(sb);
868 	else
869 		drop_super_exclusive(sb);
870 out:
871 	if (pathp && !IS_ERR(pathp))
872 		path_put(pathp);
873 	return ret;
874 }
875 
876 SYSCALL_DEFINE4(quotactl, unsigned int, cmd, const char __user *, special,
877 		qid_t, id, void __user *, addr)
878 {
879 	return kernel_quotactl(cmd, special, id, addr);
880 }
881