xref: /openbmc/linux/fs/quota/quota.c (revision 95298d63)
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 	ret = security_quotactl(Q_SYNC, type, 0, NULL);
64 	if (!ret)
65 		iterate_supers(quota_sync_one, &type);
66 	return ret;
67 }
68 
69 unsigned int qtype_enforce_flag(int type)
70 {
71 	switch (type) {
72 	case USRQUOTA:
73 		return FS_QUOTA_UDQ_ENFD;
74 	case GRPQUOTA:
75 		return FS_QUOTA_GDQ_ENFD;
76 	case PRJQUOTA:
77 		return FS_QUOTA_PDQ_ENFD;
78 	}
79 	return 0;
80 }
81 
82 static int quota_quotaon(struct super_block *sb, int type, qid_t id,
83 		         const struct path *path)
84 {
85 	if (!sb->s_qcop->quota_on && !sb->s_qcop->quota_enable)
86 		return -ENOSYS;
87 	if (sb->s_qcop->quota_enable)
88 		return sb->s_qcop->quota_enable(sb, qtype_enforce_flag(type));
89 	if (IS_ERR(path))
90 		return PTR_ERR(path);
91 	return sb->s_qcop->quota_on(sb, type, id, path);
92 }
93 
94 static int quota_quotaoff(struct super_block *sb, int type)
95 {
96 	if (!sb->s_qcop->quota_off && !sb->s_qcop->quota_disable)
97 		return -ENOSYS;
98 	if (sb->s_qcop->quota_disable)
99 		return sb->s_qcop->quota_disable(sb, qtype_enforce_flag(type));
100 	return sb->s_qcop->quota_off(sb, type);
101 }
102 
103 static int quota_getfmt(struct super_block *sb, int type, void __user *addr)
104 {
105 	__u32 fmt;
106 
107 	if (!sb_has_quota_active(sb, type))
108 		return -ESRCH;
109 	fmt = sb_dqopt(sb)->info[type].dqi_format->qf_fmt_id;
110 	if (copy_to_user(addr, &fmt, sizeof(fmt)))
111 		return -EFAULT;
112 	return 0;
113 }
114 
115 static int quota_getinfo(struct super_block *sb, int type, void __user *addr)
116 {
117 	struct qc_state state;
118 	struct qc_type_state *tstate;
119 	struct if_dqinfo uinfo;
120 	int ret;
121 
122 	if (!sb->s_qcop->get_state)
123 		return -ENOSYS;
124 	ret = sb->s_qcop->get_state(sb, &state);
125 	if (ret)
126 		return ret;
127 	tstate = state.s_state + type;
128 	if (!(tstate->flags & QCI_ACCT_ENABLED))
129 		return -ESRCH;
130 	memset(&uinfo, 0, sizeof(uinfo));
131 	uinfo.dqi_bgrace = tstate->spc_timelimit;
132 	uinfo.dqi_igrace = tstate->ino_timelimit;
133 	if (tstate->flags & QCI_SYSFILE)
134 		uinfo.dqi_flags |= DQF_SYS_FILE;
135 	if (tstate->flags & QCI_ROOT_SQUASH)
136 		uinfo.dqi_flags |= DQF_ROOT_SQUASH;
137 	uinfo.dqi_valid = IIF_ALL;
138 	if (copy_to_user(addr, &uinfo, sizeof(uinfo)))
139 		return -EFAULT;
140 	return 0;
141 }
142 
143 static int quota_setinfo(struct super_block *sb, int type, void __user *addr)
144 {
145 	struct if_dqinfo info;
146 	struct qc_info qinfo;
147 
148 	if (copy_from_user(&info, addr, sizeof(info)))
149 		return -EFAULT;
150 	if (!sb->s_qcop->set_info)
151 		return -ENOSYS;
152 	if (info.dqi_valid & ~(IIF_FLAGS | IIF_BGRACE | IIF_IGRACE))
153 		return -EINVAL;
154 	memset(&qinfo, 0, sizeof(qinfo));
155 	if (info.dqi_valid & IIF_FLAGS) {
156 		if (info.dqi_flags & ~DQF_SETINFO_MASK)
157 			return -EINVAL;
158 		if (info.dqi_flags & DQF_ROOT_SQUASH)
159 			qinfo.i_flags |= QCI_ROOT_SQUASH;
160 		qinfo.i_fieldmask |= QC_FLAGS;
161 	}
162 	if (info.dqi_valid & IIF_BGRACE) {
163 		qinfo.i_spc_timelimit = info.dqi_bgrace;
164 		qinfo.i_fieldmask |= QC_SPC_TIMER;
165 	}
166 	if (info.dqi_valid & IIF_IGRACE) {
167 		qinfo.i_ino_timelimit = info.dqi_igrace;
168 		qinfo.i_fieldmask |= QC_INO_TIMER;
169 	}
170 	return sb->s_qcop->set_info(sb, type, &qinfo);
171 }
172 
173 static inline qsize_t qbtos(qsize_t blocks)
174 {
175 	return blocks << QIF_DQBLKSIZE_BITS;
176 }
177 
178 static inline qsize_t stoqb(qsize_t space)
179 {
180 	return (space + QIF_DQBLKSIZE - 1) >> QIF_DQBLKSIZE_BITS;
181 }
182 
183 static void copy_to_if_dqblk(struct if_dqblk *dst, struct qc_dqblk *src)
184 {
185 	memset(dst, 0, sizeof(*dst));
186 	dst->dqb_bhardlimit = stoqb(src->d_spc_hardlimit);
187 	dst->dqb_bsoftlimit = stoqb(src->d_spc_softlimit);
188 	dst->dqb_curspace = src->d_space;
189 	dst->dqb_ihardlimit = src->d_ino_hardlimit;
190 	dst->dqb_isoftlimit = src->d_ino_softlimit;
191 	dst->dqb_curinodes = src->d_ino_count;
192 	dst->dqb_btime = src->d_spc_timer;
193 	dst->dqb_itime = src->d_ino_timer;
194 	dst->dqb_valid = QIF_ALL;
195 }
196 
197 static int quota_getquota(struct super_block *sb, int type, qid_t id,
198 			  void __user *addr)
199 {
200 	struct kqid qid;
201 	struct qc_dqblk fdq;
202 	struct if_dqblk idq;
203 	int ret;
204 
205 	if (!sb->s_qcop->get_dqblk)
206 		return -ENOSYS;
207 	qid = make_kqid(current_user_ns(), type, id);
208 	if (!qid_has_mapping(sb->s_user_ns, qid))
209 		return -EINVAL;
210 	ret = sb->s_qcop->get_dqblk(sb, qid, &fdq);
211 	if (ret)
212 		return ret;
213 	copy_to_if_dqblk(&idq, &fdq);
214 	if (copy_to_user(addr, &idq, sizeof(idq)))
215 		return -EFAULT;
216 	return 0;
217 }
218 
219 /*
220  * Return quota for next active quota >= this id, if any exists,
221  * otherwise return -ENOENT via ->get_nextdqblk
222  */
223 static int quota_getnextquota(struct super_block *sb, int type, qid_t id,
224 			  void __user *addr)
225 {
226 	struct kqid qid;
227 	struct qc_dqblk fdq;
228 	struct if_nextdqblk idq;
229 	int ret;
230 
231 	if (!sb->s_qcop->get_nextdqblk)
232 		return -ENOSYS;
233 	qid = make_kqid(current_user_ns(), type, id);
234 	if (!qid_has_mapping(sb->s_user_ns, qid))
235 		return -EINVAL;
236 	ret = sb->s_qcop->get_nextdqblk(sb, &qid, &fdq);
237 	if (ret)
238 		return ret;
239 	/* struct if_nextdqblk is a superset of struct if_dqblk */
240 	copy_to_if_dqblk((struct if_dqblk *)&idq, &fdq);
241 	idq.dqb_id = from_kqid(current_user_ns(), qid);
242 	if (copy_to_user(addr, &idq, sizeof(idq)))
243 		return -EFAULT;
244 	return 0;
245 }
246 
247 static void copy_from_if_dqblk(struct qc_dqblk *dst, struct if_dqblk *src)
248 {
249 	dst->d_spc_hardlimit = qbtos(src->dqb_bhardlimit);
250 	dst->d_spc_softlimit = qbtos(src->dqb_bsoftlimit);
251 	dst->d_space = src->dqb_curspace;
252 	dst->d_ino_hardlimit = src->dqb_ihardlimit;
253 	dst->d_ino_softlimit = src->dqb_isoftlimit;
254 	dst->d_ino_count = src->dqb_curinodes;
255 	dst->d_spc_timer = src->dqb_btime;
256 	dst->d_ino_timer = src->dqb_itime;
257 
258 	dst->d_fieldmask = 0;
259 	if (src->dqb_valid & QIF_BLIMITS)
260 		dst->d_fieldmask |= QC_SPC_SOFT | QC_SPC_HARD;
261 	if (src->dqb_valid & QIF_SPACE)
262 		dst->d_fieldmask |= QC_SPACE;
263 	if (src->dqb_valid & QIF_ILIMITS)
264 		dst->d_fieldmask |= QC_INO_SOFT | QC_INO_HARD;
265 	if (src->dqb_valid & QIF_INODES)
266 		dst->d_fieldmask |= QC_INO_COUNT;
267 	if (src->dqb_valid & QIF_BTIME)
268 		dst->d_fieldmask |= QC_SPC_TIMER;
269 	if (src->dqb_valid & QIF_ITIME)
270 		dst->d_fieldmask |= QC_INO_TIMER;
271 }
272 
273 static int quota_setquota(struct super_block *sb, int type, qid_t id,
274 			  void __user *addr)
275 {
276 	struct qc_dqblk fdq;
277 	struct if_dqblk idq;
278 	struct kqid qid;
279 
280 	if (copy_from_user(&idq, addr, sizeof(idq)))
281 		return -EFAULT;
282 	if (!sb->s_qcop->set_dqblk)
283 		return -ENOSYS;
284 	qid = make_kqid(current_user_ns(), type, id);
285 	if (!qid_has_mapping(sb->s_user_ns, qid))
286 		return -EINVAL;
287 	copy_from_if_dqblk(&fdq, &idq);
288 	return sb->s_qcop->set_dqblk(sb, qid, &fdq);
289 }
290 
291 static int quota_enable(struct super_block *sb, void __user *addr)
292 {
293 	__u32 flags;
294 
295 	if (copy_from_user(&flags, addr, sizeof(flags)))
296 		return -EFAULT;
297 	if (!sb->s_qcop->quota_enable)
298 		return -ENOSYS;
299 	return sb->s_qcop->quota_enable(sb, flags);
300 }
301 
302 static int quota_disable(struct super_block *sb, void __user *addr)
303 {
304 	__u32 flags;
305 
306 	if (copy_from_user(&flags, addr, sizeof(flags)))
307 		return -EFAULT;
308 	if (!sb->s_qcop->quota_disable)
309 		return -ENOSYS;
310 	return sb->s_qcop->quota_disable(sb, flags);
311 }
312 
313 static int quota_state_to_flags(struct qc_state *state)
314 {
315 	int flags = 0;
316 
317 	if (state->s_state[USRQUOTA].flags & QCI_ACCT_ENABLED)
318 		flags |= FS_QUOTA_UDQ_ACCT;
319 	if (state->s_state[USRQUOTA].flags & QCI_LIMITS_ENFORCED)
320 		flags |= FS_QUOTA_UDQ_ENFD;
321 	if (state->s_state[GRPQUOTA].flags & QCI_ACCT_ENABLED)
322 		flags |= FS_QUOTA_GDQ_ACCT;
323 	if (state->s_state[GRPQUOTA].flags & QCI_LIMITS_ENFORCED)
324 		flags |= FS_QUOTA_GDQ_ENFD;
325 	if (state->s_state[PRJQUOTA].flags & QCI_ACCT_ENABLED)
326 		flags |= FS_QUOTA_PDQ_ACCT;
327 	if (state->s_state[PRJQUOTA].flags & QCI_LIMITS_ENFORCED)
328 		flags |= FS_QUOTA_PDQ_ENFD;
329 	return flags;
330 }
331 
332 static int quota_getstate(struct super_block *sb, int type,
333 			  struct fs_quota_stat *fqs)
334 {
335 	struct qc_state state;
336 	int ret;
337 
338 	memset(&state, 0, sizeof (struct qc_state));
339 	ret = sb->s_qcop->get_state(sb, &state);
340 	if (ret < 0)
341 		return ret;
342 
343 	memset(fqs, 0, sizeof(*fqs));
344 	fqs->qs_version = FS_QSTAT_VERSION;
345 	fqs->qs_flags = quota_state_to_flags(&state);
346 	/* No quota enabled? */
347 	if (!fqs->qs_flags)
348 		return -ENOSYS;
349 	fqs->qs_incoredqs = state.s_incoredqs;
350 
351 	fqs->qs_btimelimit = state.s_state[type].spc_timelimit;
352 	fqs->qs_itimelimit = state.s_state[type].ino_timelimit;
353 	fqs->qs_rtbtimelimit = state.s_state[type].rt_spc_timelimit;
354 	fqs->qs_bwarnlimit = state.s_state[type].spc_warnlimit;
355 	fqs->qs_iwarnlimit = state.s_state[type].ino_warnlimit;
356 
357 	/* Inodes may be allocated even if inactive; copy out if present */
358 	if (state.s_state[USRQUOTA].ino) {
359 		fqs->qs_uquota.qfs_ino = state.s_state[USRQUOTA].ino;
360 		fqs->qs_uquota.qfs_nblks = state.s_state[USRQUOTA].blocks;
361 		fqs->qs_uquota.qfs_nextents = state.s_state[USRQUOTA].nextents;
362 	}
363 	if (state.s_state[GRPQUOTA].ino) {
364 		fqs->qs_gquota.qfs_ino = state.s_state[GRPQUOTA].ino;
365 		fqs->qs_gquota.qfs_nblks = state.s_state[GRPQUOTA].blocks;
366 		fqs->qs_gquota.qfs_nextents = state.s_state[GRPQUOTA].nextents;
367 	}
368 	if (state.s_state[PRJQUOTA].ino) {
369 		/*
370 		 * Q_XGETQSTAT doesn't have room for both group and project
371 		 * quotas.  So, allow the project quota values to be copied out
372 		 * only if there is no group quota information available.
373 		 */
374 		if (!(state.s_state[GRPQUOTA].flags & QCI_ACCT_ENABLED)) {
375 			fqs->qs_gquota.qfs_ino = state.s_state[PRJQUOTA].ino;
376 			fqs->qs_gquota.qfs_nblks =
377 					state.s_state[PRJQUOTA].blocks;
378 			fqs->qs_gquota.qfs_nextents =
379 					state.s_state[PRJQUOTA].nextents;
380 		}
381 	}
382 	return 0;
383 }
384 
385 static int quota_getxstate(struct super_block *sb, int type, void __user *addr)
386 {
387 	struct fs_quota_stat fqs;
388 	int ret;
389 
390 	if (!sb->s_qcop->get_state)
391 		return -ENOSYS;
392 	ret = quota_getstate(sb, type, &fqs);
393 	if (!ret && copy_to_user(addr, &fqs, sizeof(fqs)))
394 		return -EFAULT;
395 	return ret;
396 }
397 
398 static int quota_getstatev(struct super_block *sb, int type,
399 			   struct fs_quota_statv *fqs)
400 {
401 	struct qc_state state;
402 	int ret;
403 
404 	memset(&state, 0, sizeof (struct qc_state));
405 	ret = sb->s_qcop->get_state(sb, &state);
406 	if (ret < 0)
407 		return ret;
408 
409 	memset(fqs, 0, sizeof(*fqs));
410 	fqs->qs_version = FS_QSTAT_VERSION;
411 	fqs->qs_flags = quota_state_to_flags(&state);
412 	/* No quota enabled? */
413 	if (!fqs->qs_flags)
414 		return -ENOSYS;
415 	fqs->qs_incoredqs = state.s_incoredqs;
416 
417 	fqs->qs_btimelimit = state.s_state[type].spc_timelimit;
418 	fqs->qs_itimelimit = state.s_state[type].ino_timelimit;
419 	fqs->qs_rtbtimelimit = state.s_state[type].rt_spc_timelimit;
420 	fqs->qs_bwarnlimit = state.s_state[type].spc_warnlimit;
421 	fqs->qs_iwarnlimit = state.s_state[type].ino_warnlimit;
422 
423 	/* Inodes may be allocated even if inactive; copy out if present */
424 	if (state.s_state[USRQUOTA].ino) {
425 		fqs->qs_uquota.qfs_ino = state.s_state[USRQUOTA].ino;
426 		fqs->qs_uquota.qfs_nblks = state.s_state[USRQUOTA].blocks;
427 		fqs->qs_uquota.qfs_nextents = state.s_state[USRQUOTA].nextents;
428 	}
429 	if (state.s_state[GRPQUOTA].ino) {
430 		fqs->qs_gquota.qfs_ino = state.s_state[GRPQUOTA].ino;
431 		fqs->qs_gquota.qfs_nblks = state.s_state[GRPQUOTA].blocks;
432 		fqs->qs_gquota.qfs_nextents = state.s_state[GRPQUOTA].nextents;
433 	}
434 	if (state.s_state[PRJQUOTA].ino) {
435 		fqs->qs_pquota.qfs_ino = state.s_state[PRJQUOTA].ino;
436 		fqs->qs_pquota.qfs_nblks = state.s_state[PRJQUOTA].blocks;
437 		fqs->qs_pquota.qfs_nextents = state.s_state[PRJQUOTA].nextents;
438 	}
439 	return 0;
440 }
441 
442 static int quota_getxstatev(struct super_block *sb, int type, void __user *addr)
443 {
444 	struct fs_quota_statv fqs;
445 	int ret;
446 
447 	if (!sb->s_qcop->get_state)
448 		return -ENOSYS;
449 
450 	memset(&fqs, 0, sizeof(fqs));
451 	if (copy_from_user(&fqs, addr, 1)) /* Just read qs_version */
452 		return -EFAULT;
453 
454 	/* If this kernel doesn't support user specified version, fail */
455 	switch (fqs.qs_version) {
456 	case FS_QSTATV_VERSION1:
457 		break;
458 	default:
459 		return -EINVAL;
460 	}
461 	ret = quota_getstatev(sb, type, &fqs);
462 	if (!ret && copy_to_user(addr, &fqs, sizeof(fqs)))
463 		return -EFAULT;
464 	return ret;
465 }
466 
467 /*
468  * XFS defines BBTOB and BTOBB macros inside fs/xfs/ and we cannot move them
469  * out of there as xfsprogs rely on definitions being in that header file. So
470  * just define same functions here for quota purposes.
471  */
472 #define XFS_BB_SHIFT 9
473 
474 static inline u64 quota_bbtob(u64 blocks)
475 {
476 	return blocks << XFS_BB_SHIFT;
477 }
478 
479 static inline u64 quota_btobb(u64 bytes)
480 {
481 	return (bytes + (1 << XFS_BB_SHIFT) - 1) >> XFS_BB_SHIFT;
482 }
483 
484 static void copy_from_xfs_dqblk(struct qc_dqblk *dst, struct fs_disk_quota *src)
485 {
486 	dst->d_spc_hardlimit = quota_bbtob(src->d_blk_hardlimit);
487 	dst->d_spc_softlimit = quota_bbtob(src->d_blk_softlimit);
488 	dst->d_ino_hardlimit = src->d_ino_hardlimit;
489 	dst->d_ino_softlimit = src->d_ino_softlimit;
490 	dst->d_space = quota_bbtob(src->d_bcount);
491 	dst->d_ino_count = src->d_icount;
492 	dst->d_ino_timer = src->d_itimer;
493 	dst->d_spc_timer = src->d_btimer;
494 	dst->d_ino_warns = src->d_iwarns;
495 	dst->d_spc_warns = src->d_bwarns;
496 	dst->d_rt_spc_hardlimit = quota_bbtob(src->d_rtb_hardlimit);
497 	dst->d_rt_spc_softlimit = quota_bbtob(src->d_rtb_softlimit);
498 	dst->d_rt_space = quota_bbtob(src->d_rtbcount);
499 	dst->d_rt_spc_timer = src->d_rtbtimer;
500 	dst->d_rt_spc_warns = src->d_rtbwarns;
501 	dst->d_fieldmask = 0;
502 	if (src->d_fieldmask & FS_DQ_ISOFT)
503 		dst->d_fieldmask |= QC_INO_SOFT;
504 	if (src->d_fieldmask & FS_DQ_IHARD)
505 		dst->d_fieldmask |= QC_INO_HARD;
506 	if (src->d_fieldmask & FS_DQ_BSOFT)
507 		dst->d_fieldmask |= QC_SPC_SOFT;
508 	if (src->d_fieldmask & FS_DQ_BHARD)
509 		dst->d_fieldmask |= QC_SPC_HARD;
510 	if (src->d_fieldmask & FS_DQ_RTBSOFT)
511 		dst->d_fieldmask |= QC_RT_SPC_SOFT;
512 	if (src->d_fieldmask & FS_DQ_RTBHARD)
513 		dst->d_fieldmask |= QC_RT_SPC_HARD;
514 	if (src->d_fieldmask & FS_DQ_BTIMER)
515 		dst->d_fieldmask |= QC_SPC_TIMER;
516 	if (src->d_fieldmask & FS_DQ_ITIMER)
517 		dst->d_fieldmask |= QC_INO_TIMER;
518 	if (src->d_fieldmask & FS_DQ_RTBTIMER)
519 		dst->d_fieldmask |= QC_RT_SPC_TIMER;
520 	if (src->d_fieldmask & FS_DQ_BWARNS)
521 		dst->d_fieldmask |= QC_SPC_WARNS;
522 	if (src->d_fieldmask & FS_DQ_IWARNS)
523 		dst->d_fieldmask |= QC_INO_WARNS;
524 	if (src->d_fieldmask & FS_DQ_RTBWARNS)
525 		dst->d_fieldmask |= QC_RT_SPC_WARNS;
526 	if (src->d_fieldmask & FS_DQ_BCOUNT)
527 		dst->d_fieldmask |= QC_SPACE;
528 	if (src->d_fieldmask & FS_DQ_ICOUNT)
529 		dst->d_fieldmask |= QC_INO_COUNT;
530 	if (src->d_fieldmask & FS_DQ_RTBCOUNT)
531 		dst->d_fieldmask |= QC_RT_SPACE;
532 }
533 
534 static void copy_qcinfo_from_xfs_dqblk(struct qc_info *dst,
535 				       struct fs_disk_quota *src)
536 {
537 	memset(dst, 0, sizeof(*dst));
538 	dst->i_spc_timelimit = src->d_btimer;
539 	dst->i_ino_timelimit = src->d_itimer;
540 	dst->i_rt_spc_timelimit = src->d_rtbtimer;
541 	dst->i_ino_warnlimit = src->d_iwarns;
542 	dst->i_spc_warnlimit = src->d_bwarns;
543 	dst->i_rt_spc_warnlimit = src->d_rtbwarns;
544 	if (src->d_fieldmask & FS_DQ_BWARNS)
545 		dst->i_fieldmask |= QC_SPC_WARNS;
546 	if (src->d_fieldmask & FS_DQ_IWARNS)
547 		dst->i_fieldmask |= QC_INO_WARNS;
548 	if (src->d_fieldmask & FS_DQ_RTBWARNS)
549 		dst->i_fieldmask |= QC_RT_SPC_WARNS;
550 	if (src->d_fieldmask & FS_DQ_BTIMER)
551 		dst->i_fieldmask |= QC_SPC_TIMER;
552 	if (src->d_fieldmask & FS_DQ_ITIMER)
553 		dst->i_fieldmask |= QC_INO_TIMER;
554 	if (src->d_fieldmask & FS_DQ_RTBTIMER)
555 		dst->i_fieldmask |= QC_RT_SPC_TIMER;
556 }
557 
558 static int quota_setxquota(struct super_block *sb, int type, qid_t id,
559 			   void __user *addr)
560 {
561 	struct fs_disk_quota fdq;
562 	struct qc_dqblk qdq;
563 	struct kqid qid;
564 
565 	if (copy_from_user(&fdq, addr, sizeof(fdq)))
566 		return -EFAULT;
567 	if (!sb->s_qcop->set_dqblk)
568 		return -ENOSYS;
569 	qid = make_kqid(current_user_ns(), type, id);
570 	if (!qid_has_mapping(sb->s_user_ns, qid))
571 		return -EINVAL;
572 	/* Are we actually setting timer / warning limits for all users? */
573 	if (from_kqid(sb->s_user_ns, qid) == 0 &&
574 	    fdq.d_fieldmask & (FS_DQ_WARNS_MASK | FS_DQ_TIMER_MASK)) {
575 		struct qc_info qinfo;
576 		int ret;
577 
578 		if (!sb->s_qcop->set_info)
579 			return -EINVAL;
580 		copy_qcinfo_from_xfs_dqblk(&qinfo, &fdq);
581 		ret = sb->s_qcop->set_info(sb, type, &qinfo);
582 		if (ret)
583 			return ret;
584 		/* These are already done */
585 		fdq.d_fieldmask &= ~(FS_DQ_WARNS_MASK | FS_DQ_TIMER_MASK);
586 	}
587 	copy_from_xfs_dqblk(&qdq, &fdq);
588 	return sb->s_qcop->set_dqblk(sb, qid, &qdq);
589 }
590 
591 static void copy_to_xfs_dqblk(struct fs_disk_quota *dst, struct qc_dqblk *src,
592 			      int type, qid_t id)
593 {
594 	memset(dst, 0, sizeof(*dst));
595 	dst->d_version = FS_DQUOT_VERSION;
596 	dst->d_id = id;
597 	if (type == USRQUOTA)
598 		dst->d_flags = FS_USER_QUOTA;
599 	else if (type == PRJQUOTA)
600 		dst->d_flags = FS_PROJ_QUOTA;
601 	else
602 		dst->d_flags = FS_GROUP_QUOTA;
603 	dst->d_blk_hardlimit = quota_btobb(src->d_spc_hardlimit);
604 	dst->d_blk_softlimit = quota_btobb(src->d_spc_softlimit);
605 	dst->d_ino_hardlimit = src->d_ino_hardlimit;
606 	dst->d_ino_softlimit = src->d_ino_softlimit;
607 	dst->d_bcount = quota_btobb(src->d_space);
608 	dst->d_icount = src->d_ino_count;
609 	dst->d_itimer = src->d_ino_timer;
610 	dst->d_btimer = src->d_spc_timer;
611 	dst->d_iwarns = src->d_ino_warns;
612 	dst->d_bwarns = src->d_spc_warns;
613 	dst->d_rtb_hardlimit = quota_btobb(src->d_rt_spc_hardlimit);
614 	dst->d_rtb_softlimit = quota_btobb(src->d_rt_spc_softlimit);
615 	dst->d_rtbcount = quota_btobb(src->d_rt_space);
616 	dst->d_rtbtimer = src->d_rt_spc_timer;
617 	dst->d_rtbwarns = src->d_rt_spc_warns;
618 }
619 
620 static int quota_getxquota(struct super_block *sb, int type, qid_t id,
621 			   void __user *addr)
622 {
623 	struct fs_disk_quota fdq;
624 	struct qc_dqblk qdq;
625 	struct kqid qid;
626 	int ret;
627 
628 	if (!sb->s_qcop->get_dqblk)
629 		return -ENOSYS;
630 	qid = make_kqid(current_user_ns(), type, id);
631 	if (!qid_has_mapping(sb->s_user_ns, qid))
632 		return -EINVAL;
633 	ret = sb->s_qcop->get_dqblk(sb, qid, &qdq);
634 	if (ret)
635 		return ret;
636 	copy_to_xfs_dqblk(&fdq, &qdq, type, id);
637 	if (copy_to_user(addr, &fdq, sizeof(fdq)))
638 		return -EFAULT;
639 	return ret;
640 }
641 
642 /*
643  * Return quota for next active quota >= this id, if any exists,
644  * otherwise return -ENOENT via ->get_nextdqblk.
645  */
646 static int quota_getnextxquota(struct super_block *sb, int type, qid_t id,
647 			    void __user *addr)
648 {
649 	struct fs_disk_quota fdq;
650 	struct qc_dqblk qdq;
651 	struct kqid qid;
652 	qid_t id_out;
653 	int ret;
654 
655 	if (!sb->s_qcop->get_nextdqblk)
656 		return -ENOSYS;
657 	qid = make_kqid(current_user_ns(), type, id);
658 	if (!qid_has_mapping(sb->s_user_ns, qid))
659 		return -EINVAL;
660 	ret = sb->s_qcop->get_nextdqblk(sb, &qid, &qdq);
661 	if (ret)
662 		return ret;
663 	id_out = from_kqid(current_user_ns(), qid);
664 	copy_to_xfs_dqblk(&fdq, &qdq, type, id_out);
665 	if (copy_to_user(addr, &fdq, sizeof(fdq)))
666 		return -EFAULT;
667 	return ret;
668 }
669 
670 static int quota_rmxquota(struct super_block *sb, void __user *addr)
671 {
672 	__u32 flags;
673 
674 	if (copy_from_user(&flags, addr, sizeof(flags)))
675 		return -EFAULT;
676 	if (!sb->s_qcop->rm_xquota)
677 		return -ENOSYS;
678 	return sb->s_qcop->rm_xquota(sb, flags);
679 }
680 
681 /* Copy parameters and call proper function */
682 static int do_quotactl(struct super_block *sb, int type, int cmd, qid_t id,
683 		       void __user *addr, const struct path *path)
684 {
685 	int ret;
686 
687 	type = array_index_nospec(type, MAXQUOTAS);
688 	/*
689 	 * Quota not supported on this fs? Check this before s_quota_types
690 	 * since they needn't be set if quota is not supported at all.
691 	 */
692 	if (!sb->s_qcop)
693 		return -ENOSYS;
694 	if (!(sb->s_quota_types & (1 << type)))
695 		return -EINVAL;
696 
697 	ret = check_quotactl_permission(sb, type, cmd, id);
698 	if (ret < 0)
699 		return ret;
700 
701 	switch (cmd) {
702 	case Q_QUOTAON:
703 		return quota_quotaon(sb, type, id, path);
704 	case Q_QUOTAOFF:
705 		return quota_quotaoff(sb, type);
706 	case Q_GETFMT:
707 		return quota_getfmt(sb, type, addr);
708 	case Q_GETINFO:
709 		return quota_getinfo(sb, type, addr);
710 	case Q_SETINFO:
711 		return quota_setinfo(sb, type, addr);
712 	case Q_GETQUOTA:
713 		return quota_getquota(sb, type, id, addr);
714 	case Q_GETNEXTQUOTA:
715 		return quota_getnextquota(sb, type, id, addr);
716 	case Q_SETQUOTA:
717 		return quota_setquota(sb, type, id, addr);
718 	case Q_SYNC:
719 		if (!sb->s_qcop->quota_sync)
720 			return -ENOSYS;
721 		return sb->s_qcop->quota_sync(sb, type);
722 	case Q_XQUOTAON:
723 		return quota_enable(sb, addr);
724 	case Q_XQUOTAOFF:
725 		return quota_disable(sb, addr);
726 	case Q_XQUOTARM:
727 		return quota_rmxquota(sb, addr);
728 	case Q_XGETQSTAT:
729 		return quota_getxstate(sb, type, addr);
730 	case Q_XGETQSTATV:
731 		return quota_getxstatev(sb, type, addr);
732 	case Q_XSETQLIM:
733 		return quota_setxquota(sb, type, id, addr);
734 	case Q_XGETQUOTA:
735 		return quota_getxquota(sb, type, id, addr);
736 	case Q_XGETNEXTQUOTA:
737 		return quota_getnextxquota(sb, type, id, addr);
738 	case Q_XQUOTASYNC:
739 		if (sb_rdonly(sb))
740 			return -EROFS;
741 		/* XFS quotas are fully coherent now, making this call a noop */
742 		return 0;
743 	default:
744 		return -EINVAL;
745 	}
746 }
747 
748 #ifdef CONFIG_BLOCK
749 
750 /* Return 1 if 'cmd' will block on frozen filesystem */
751 static int quotactl_cmd_write(int cmd)
752 {
753 	/*
754 	 * We cannot allow Q_GETQUOTA and Q_GETNEXTQUOTA without write access
755 	 * as dquot_acquire() may allocate space for new structure and OCFS2
756 	 * needs to increment on-disk use count.
757 	 */
758 	switch (cmd) {
759 	case Q_GETFMT:
760 	case Q_GETINFO:
761 	case Q_SYNC:
762 	case Q_XGETQSTAT:
763 	case Q_XGETQSTATV:
764 	case Q_XGETQUOTA:
765 	case Q_XGETNEXTQUOTA:
766 	case Q_XQUOTASYNC:
767 		return 0;
768 	}
769 	return 1;
770 }
771 #endif /* CONFIG_BLOCK */
772 
773 /* Return true if quotactl command is manipulating quota on/off state */
774 static bool quotactl_cmd_onoff(int cmd)
775 {
776 	return (cmd == Q_QUOTAON) || (cmd == Q_QUOTAOFF) ||
777 		 (cmd == Q_XQUOTAON) || (cmd == Q_XQUOTAOFF);
778 }
779 
780 /*
781  * look up a superblock on which quota ops will be performed
782  * - use the name of a block device to find the superblock thereon
783  */
784 static struct super_block *quotactl_block(const char __user *special, int cmd)
785 {
786 #ifdef CONFIG_BLOCK
787 	struct block_device *bdev;
788 	struct super_block *sb;
789 	struct filename *tmp = getname(special);
790 
791 	if (IS_ERR(tmp))
792 		return ERR_CAST(tmp);
793 	bdev = lookup_bdev(tmp->name);
794 	putname(tmp);
795 	if (IS_ERR(bdev))
796 		return ERR_CAST(bdev);
797 	if (quotactl_cmd_onoff(cmd))
798 		sb = get_super_exclusive_thawed(bdev);
799 	else if (quotactl_cmd_write(cmd))
800 		sb = get_super_thawed(bdev);
801 	else
802 		sb = get_super(bdev);
803 	bdput(bdev);
804 	if (!sb)
805 		return ERR_PTR(-ENODEV);
806 
807 	return sb;
808 #else
809 	return ERR_PTR(-ENODEV);
810 #endif
811 }
812 
813 /*
814  * This is the system call interface. This communicates with
815  * the user-level programs. Currently this only supports diskquota
816  * calls. Maybe we need to add the process quotas etc. in the future,
817  * but we probably should use rlimits for that.
818  */
819 int kernel_quotactl(unsigned int cmd, const char __user *special,
820 		    qid_t id, void __user *addr)
821 {
822 	uint cmds, type;
823 	struct super_block *sb = NULL;
824 	struct path path, *pathp = NULL;
825 	int ret;
826 
827 	cmds = cmd >> SUBCMDSHIFT;
828 	type = cmd & SUBCMDMASK;
829 
830 	if (type >= MAXQUOTAS)
831 		return -EINVAL;
832 
833 	/*
834 	 * As a special case Q_SYNC can be called without a specific device.
835 	 * It will iterate all superblocks that have quota enabled and call
836 	 * the sync action on each of them.
837 	 */
838 	if (!special) {
839 		if (cmds == Q_SYNC)
840 			return quota_sync_all(type);
841 		return -ENODEV;
842 	}
843 
844 	/*
845 	 * Path for quotaon has to be resolved before grabbing superblock
846 	 * because that gets s_umount sem which is also possibly needed by path
847 	 * resolution (think about autofs) and thus deadlocks could arise.
848 	 */
849 	if (cmds == Q_QUOTAON) {
850 		ret = user_path_at(AT_FDCWD, addr, LOOKUP_FOLLOW|LOOKUP_AUTOMOUNT, &path);
851 		if (ret)
852 			pathp = ERR_PTR(ret);
853 		else
854 			pathp = &path;
855 	}
856 
857 	sb = quotactl_block(special, cmds);
858 	if (IS_ERR(sb)) {
859 		ret = PTR_ERR(sb);
860 		goto out;
861 	}
862 
863 	ret = do_quotactl(sb, type, cmds, id, addr, pathp);
864 
865 	if (!quotactl_cmd_onoff(cmds))
866 		drop_super(sb);
867 	else
868 		drop_super_exclusive(sb);
869 out:
870 	if (pathp && !IS_ERR(pathp))
871 		path_put(pathp);
872 	return ret;
873 }
874 
875 SYSCALL_DEFINE4(quotactl, unsigned int, cmd, const char __user *, special,
876 		qid_t, id, void __user *, addr)
877 {
878 	return kernel_quotactl(cmd, special, id, addr);
879 }
880