xref: /linux/fs/quota/quota.c (revision c0e297dc61f8d4453e07afbea1fa8d0e67cd4a34)
1 /*
2  * Quota code necessary even when VFS quota support is not compiled
3  * into the kernel.  The interesting stuff is over in dquot.c, here
4  * we have symbols for initial quotactl(2) handling, the sysctl(2)
5  * variables, etc - things needed even when quota support disabled.
6  */
7 
8 #include <linux/fs.h>
9 #include <linux/namei.h>
10 #include <linux/slab.h>
11 #include <asm/current.h>
12 #include <linux/uaccess.h>
13 #include <linux/kernel.h>
14 #include <linux/security.h>
15 #include <linux/syscalls.h>
16 #include <linux/capability.h>
17 #include <linux/quotaops.h>
18 #include <linux/types.h>
19 #include <linux/writeback.h>
20 
21 static int check_quotactl_permission(struct super_block *sb, int type, int cmd,
22 				     qid_t id)
23 {
24 	switch (cmd) {
25 	/* these commands do not require any special privilegues */
26 	case Q_GETFMT:
27 	case Q_SYNC:
28 	case Q_GETINFO:
29 	case Q_XGETQSTAT:
30 	case Q_XGETQSTATV:
31 	case Q_XQUOTASYNC:
32 		break;
33 	/* allow to query information for dquots we "own" */
34 	case Q_GETQUOTA:
35 	case Q_XGETQUOTA:
36 		if ((type == USRQUOTA && uid_eq(current_euid(), make_kuid(current_user_ns(), id))) ||
37 		    (type == GRPQUOTA && in_egroup_p(make_kgid(current_user_ns(), id))))
38 			break;
39 		/*FALLTHROUGH*/
40 	default:
41 		if (!capable(CAP_SYS_ADMIN))
42 			return -EPERM;
43 	}
44 
45 	return security_quotactl(cmd, type, id, sb);
46 }
47 
48 static void quota_sync_one(struct super_block *sb, void *arg)
49 {
50 	int type = *(int *)arg;
51 
52 	if (sb->s_qcop && sb->s_qcop->quota_sync &&
53 	    (sb->s_quota_types & (1 << type)))
54 		sb->s_qcop->quota_sync(sb, type);
55 }
56 
57 static int quota_sync_all(int type)
58 {
59 	int ret;
60 
61 	if (type >= MAXQUOTAS)
62 		return -EINVAL;
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, int cmd, qid_t id,
83 		         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 	mutex_lock(&sb_dqopt(sb)->dqonoff_mutex);
108 	if (!sb_has_quota_active(sb, type)) {
109 		mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
110 		return -ESRCH;
111 	}
112 	fmt = sb_dqopt(sb)->info[type].dqi_format->qf_fmt_id;
113 	mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
114 	if (copy_to_user(addr, &fmt, sizeof(fmt)))
115 		return -EFAULT;
116 	return 0;
117 }
118 
119 static int quota_getinfo(struct super_block *sb, int type, void __user *addr)
120 {
121 	struct qc_state state;
122 	struct qc_type_state *tstate;
123 	struct if_dqinfo uinfo;
124 	int ret;
125 
126 	/* This checks whether qc_state has enough entries... */
127 	BUILD_BUG_ON(MAXQUOTAS > XQM_MAXQUOTAS);
128 	if (!sb->s_qcop->get_state)
129 		return -ENOSYS;
130 	ret = sb->s_qcop->get_state(sb, &state);
131 	if (ret)
132 		return ret;
133 	tstate = state.s_state + type;
134 	if (!(tstate->flags & QCI_ACCT_ENABLED))
135 		return -ESRCH;
136 	memset(&uinfo, 0, sizeof(uinfo));
137 	uinfo.dqi_bgrace = tstate->spc_timelimit;
138 	uinfo.dqi_igrace = tstate->ino_timelimit;
139 	if (tstate->flags & QCI_SYSFILE)
140 		uinfo.dqi_flags |= DQF_SYS_FILE;
141 	if (tstate->flags & QCI_ROOT_SQUASH)
142 		uinfo.dqi_flags |= DQF_ROOT_SQUASH;
143 	uinfo.dqi_valid = IIF_ALL;
144 	if (!ret && copy_to_user(addr, &uinfo, sizeof(uinfo)))
145 		return -EFAULT;
146 	return ret;
147 }
148 
149 static int quota_setinfo(struct super_block *sb, int type, void __user *addr)
150 {
151 	struct if_dqinfo info;
152 	struct qc_info qinfo;
153 
154 	if (copy_from_user(&info, addr, sizeof(info)))
155 		return -EFAULT;
156 	if (!sb->s_qcop->set_info)
157 		return -ENOSYS;
158 	if (info.dqi_valid & ~(IIF_FLAGS | IIF_BGRACE | IIF_IGRACE))
159 		return -EINVAL;
160 	memset(&qinfo, 0, sizeof(qinfo));
161 	if (info.dqi_valid & IIF_FLAGS) {
162 		if (info.dqi_flags & ~DQF_SETINFO_MASK)
163 			return -EINVAL;
164 		if (info.dqi_flags & DQF_ROOT_SQUASH)
165 			qinfo.i_flags |= QCI_ROOT_SQUASH;
166 		qinfo.i_fieldmask |= QC_FLAGS;
167 	}
168 	if (info.dqi_valid & IIF_BGRACE) {
169 		qinfo.i_spc_timelimit = info.dqi_bgrace;
170 		qinfo.i_fieldmask |= QC_SPC_TIMER;
171 	}
172 	if (info.dqi_valid & IIF_IGRACE) {
173 		qinfo.i_ino_timelimit = info.dqi_igrace;
174 		qinfo.i_fieldmask |= QC_INO_TIMER;
175 	}
176 	return sb->s_qcop->set_info(sb, type, &qinfo);
177 }
178 
179 static inline qsize_t qbtos(qsize_t blocks)
180 {
181 	return blocks << QIF_DQBLKSIZE_BITS;
182 }
183 
184 static inline qsize_t stoqb(qsize_t space)
185 {
186 	return (space + QIF_DQBLKSIZE - 1) >> QIF_DQBLKSIZE_BITS;
187 }
188 
189 static void copy_to_if_dqblk(struct if_dqblk *dst, struct qc_dqblk *src)
190 {
191 	memset(dst, 0, sizeof(*dst));
192 	dst->dqb_bhardlimit = stoqb(src->d_spc_hardlimit);
193 	dst->dqb_bsoftlimit = stoqb(src->d_spc_softlimit);
194 	dst->dqb_curspace = src->d_space;
195 	dst->dqb_ihardlimit = src->d_ino_hardlimit;
196 	dst->dqb_isoftlimit = src->d_ino_softlimit;
197 	dst->dqb_curinodes = src->d_ino_count;
198 	dst->dqb_btime = src->d_spc_timer;
199 	dst->dqb_itime = src->d_ino_timer;
200 	dst->dqb_valid = QIF_ALL;
201 }
202 
203 static int quota_getquota(struct super_block *sb, int type, qid_t id,
204 			  void __user *addr)
205 {
206 	struct kqid qid;
207 	struct qc_dqblk fdq;
208 	struct if_dqblk idq;
209 	int ret;
210 
211 	if (!sb->s_qcop->get_dqblk)
212 		return -ENOSYS;
213 	qid = make_kqid(current_user_ns(), type, id);
214 	if (!qid_valid(qid))
215 		return -EINVAL;
216 	ret = sb->s_qcop->get_dqblk(sb, qid, &fdq);
217 	if (ret)
218 		return ret;
219 	copy_to_if_dqblk(&idq, &fdq);
220 	if (copy_to_user(addr, &idq, sizeof(idq)))
221 		return -EFAULT;
222 	return 0;
223 }
224 
225 static void copy_from_if_dqblk(struct qc_dqblk *dst, struct if_dqblk *src)
226 {
227 	dst->d_spc_hardlimit = qbtos(src->dqb_bhardlimit);
228 	dst->d_spc_softlimit = qbtos(src->dqb_bsoftlimit);
229 	dst->d_space = src->dqb_curspace;
230 	dst->d_ino_hardlimit = src->dqb_ihardlimit;
231 	dst->d_ino_softlimit = src->dqb_isoftlimit;
232 	dst->d_ino_count = src->dqb_curinodes;
233 	dst->d_spc_timer = src->dqb_btime;
234 	dst->d_ino_timer = src->dqb_itime;
235 
236 	dst->d_fieldmask = 0;
237 	if (src->dqb_valid & QIF_BLIMITS)
238 		dst->d_fieldmask |= QC_SPC_SOFT | QC_SPC_HARD;
239 	if (src->dqb_valid & QIF_SPACE)
240 		dst->d_fieldmask |= QC_SPACE;
241 	if (src->dqb_valid & QIF_ILIMITS)
242 		dst->d_fieldmask |= QC_INO_SOFT | QC_INO_HARD;
243 	if (src->dqb_valid & QIF_INODES)
244 		dst->d_fieldmask |= QC_INO_COUNT;
245 	if (src->dqb_valid & QIF_BTIME)
246 		dst->d_fieldmask |= QC_SPC_TIMER;
247 	if (src->dqb_valid & QIF_ITIME)
248 		dst->d_fieldmask |= QC_INO_TIMER;
249 }
250 
251 static int quota_setquota(struct super_block *sb, int type, qid_t id,
252 			  void __user *addr)
253 {
254 	struct qc_dqblk fdq;
255 	struct if_dqblk idq;
256 	struct kqid qid;
257 
258 	if (copy_from_user(&idq, addr, sizeof(idq)))
259 		return -EFAULT;
260 	if (!sb->s_qcop->set_dqblk)
261 		return -ENOSYS;
262 	qid = make_kqid(current_user_ns(), type, id);
263 	if (!qid_valid(qid))
264 		return -EINVAL;
265 	copy_from_if_dqblk(&fdq, &idq);
266 	return sb->s_qcop->set_dqblk(sb, qid, &fdq);
267 }
268 
269 static int quota_enable(struct super_block *sb, void __user *addr)
270 {
271 	__u32 flags;
272 
273 	if (copy_from_user(&flags, addr, sizeof(flags)))
274 		return -EFAULT;
275 	if (!sb->s_qcop->quota_enable)
276 		return -ENOSYS;
277 	return sb->s_qcop->quota_enable(sb, flags);
278 }
279 
280 static int quota_disable(struct super_block *sb, void __user *addr)
281 {
282 	__u32 flags;
283 
284 	if (copy_from_user(&flags, addr, sizeof(flags)))
285 		return -EFAULT;
286 	if (!sb->s_qcop->quota_disable)
287 		return -ENOSYS;
288 	return sb->s_qcop->quota_disable(sb, flags);
289 }
290 
291 static int quota_state_to_flags(struct qc_state *state)
292 {
293 	int flags = 0;
294 
295 	if (state->s_state[USRQUOTA].flags & QCI_ACCT_ENABLED)
296 		flags |= FS_QUOTA_UDQ_ACCT;
297 	if (state->s_state[USRQUOTA].flags & QCI_LIMITS_ENFORCED)
298 		flags |= FS_QUOTA_UDQ_ENFD;
299 	if (state->s_state[GRPQUOTA].flags & QCI_ACCT_ENABLED)
300 		flags |= FS_QUOTA_GDQ_ACCT;
301 	if (state->s_state[GRPQUOTA].flags & QCI_LIMITS_ENFORCED)
302 		flags |= FS_QUOTA_GDQ_ENFD;
303 	if (state->s_state[PRJQUOTA].flags & QCI_ACCT_ENABLED)
304 		flags |= FS_QUOTA_PDQ_ACCT;
305 	if (state->s_state[PRJQUOTA].flags & QCI_LIMITS_ENFORCED)
306 		flags |= FS_QUOTA_PDQ_ENFD;
307 	return flags;
308 }
309 
310 static int quota_getstate(struct super_block *sb, struct fs_quota_stat *fqs)
311 {
312 	int type;
313 	struct qc_state state;
314 	int ret;
315 
316 	ret = sb->s_qcop->get_state(sb, &state);
317 	if (ret < 0)
318 		return ret;
319 
320 	memset(fqs, 0, sizeof(*fqs));
321 	fqs->qs_version = FS_QSTAT_VERSION;
322 	fqs->qs_flags = quota_state_to_flags(&state);
323 	/* No quota enabled? */
324 	if (!fqs->qs_flags)
325 		return -ENOSYS;
326 	fqs->qs_incoredqs = state.s_incoredqs;
327 	/*
328 	 * GETXSTATE quotactl has space for just one set of time limits so
329 	 * report them for the first enabled quota type
330 	 */
331 	for (type = 0; type < XQM_MAXQUOTAS; type++)
332 		if (state.s_state[type].flags & QCI_ACCT_ENABLED)
333 			break;
334 	BUG_ON(type == XQM_MAXQUOTAS);
335 	fqs->qs_btimelimit = state.s_state[type].spc_timelimit;
336 	fqs->qs_itimelimit = state.s_state[type].ino_timelimit;
337 	fqs->qs_rtbtimelimit = state.s_state[type].rt_spc_timelimit;
338 	fqs->qs_bwarnlimit = state.s_state[type].spc_warnlimit;
339 	fqs->qs_iwarnlimit = state.s_state[type].ino_warnlimit;
340 	if (state.s_state[USRQUOTA].flags & QCI_ACCT_ENABLED) {
341 		fqs->qs_uquota.qfs_ino = state.s_state[USRQUOTA].ino;
342 		fqs->qs_uquota.qfs_nblks = state.s_state[USRQUOTA].blocks;
343 		fqs->qs_uquota.qfs_nextents = state.s_state[USRQUOTA].nextents;
344 	}
345 	if (state.s_state[GRPQUOTA].flags & QCI_ACCT_ENABLED) {
346 		fqs->qs_gquota.qfs_ino = state.s_state[GRPQUOTA].ino;
347 		fqs->qs_gquota.qfs_nblks = state.s_state[GRPQUOTA].blocks;
348 		fqs->qs_gquota.qfs_nextents = state.s_state[GRPQUOTA].nextents;
349 	}
350 	if (state.s_state[PRJQUOTA].flags & QCI_ACCT_ENABLED) {
351 		/*
352 		 * Q_XGETQSTAT doesn't have room for both group and project
353 		 * quotas.  So, allow the project quota values to be copied out
354 		 * only if there is no group quota information available.
355 		 */
356 		if (!(state.s_state[GRPQUOTA].flags & QCI_ACCT_ENABLED)) {
357 			fqs->qs_gquota.qfs_ino = state.s_state[PRJQUOTA].ino;
358 			fqs->qs_gquota.qfs_nblks =
359 					state.s_state[PRJQUOTA].blocks;
360 			fqs->qs_gquota.qfs_nextents =
361 					state.s_state[PRJQUOTA].nextents;
362 		}
363 	}
364 	return 0;
365 }
366 
367 static int quota_getxstate(struct super_block *sb, void __user *addr)
368 {
369 	struct fs_quota_stat fqs;
370 	int ret;
371 
372 	if (!sb->s_qcop->get_state)
373 		return -ENOSYS;
374 	ret = quota_getstate(sb, &fqs);
375 	if (!ret && copy_to_user(addr, &fqs, sizeof(fqs)))
376 		return -EFAULT;
377 	return ret;
378 }
379 
380 static int quota_getstatev(struct super_block *sb, struct fs_quota_statv *fqs)
381 {
382 	int type;
383 	struct qc_state state;
384 	int ret;
385 
386 	ret = sb->s_qcop->get_state(sb, &state);
387 	if (ret < 0)
388 		return ret;
389 
390 	memset(fqs, 0, sizeof(*fqs));
391 	fqs->qs_version = FS_QSTAT_VERSION;
392 	fqs->qs_flags = quota_state_to_flags(&state);
393 	/* No quota enabled? */
394 	if (!fqs->qs_flags)
395 		return -ENOSYS;
396 	fqs->qs_incoredqs = state.s_incoredqs;
397 	/*
398 	 * GETXSTATV quotactl has space for just one set of time limits so
399 	 * report them for the first enabled quota type
400 	 */
401 	for (type = 0; type < XQM_MAXQUOTAS; type++)
402 		if (state.s_state[type].flags & QCI_ACCT_ENABLED)
403 			break;
404 	BUG_ON(type == XQM_MAXQUOTAS);
405 	fqs->qs_btimelimit = state.s_state[type].spc_timelimit;
406 	fqs->qs_itimelimit = state.s_state[type].ino_timelimit;
407 	fqs->qs_rtbtimelimit = state.s_state[type].rt_spc_timelimit;
408 	fqs->qs_bwarnlimit = state.s_state[type].spc_warnlimit;
409 	fqs->qs_iwarnlimit = state.s_state[type].ino_warnlimit;
410 	if (state.s_state[USRQUOTA].flags & QCI_ACCT_ENABLED) {
411 		fqs->qs_uquota.qfs_ino = state.s_state[USRQUOTA].ino;
412 		fqs->qs_uquota.qfs_nblks = state.s_state[USRQUOTA].blocks;
413 		fqs->qs_uquota.qfs_nextents = state.s_state[USRQUOTA].nextents;
414 	}
415 	if (state.s_state[GRPQUOTA].flags & QCI_ACCT_ENABLED) {
416 		fqs->qs_gquota.qfs_ino = state.s_state[GRPQUOTA].ino;
417 		fqs->qs_gquota.qfs_nblks = state.s_state[GRPQUOTA].blocks;
418 		fqs->qs_gquota.qfs_nextents = state.s_state[GRPQUOTA].nextents;
419 	}
420 	if (state.s_state[PRJQUOTA].flags & QCI_ACCT_ENABLED) {
421 		fqs->qs_pquota.qfs_ino = state.s_state[PRJQUOTA].ino;
422 		fqs->qs_pquota.qfs_nblks = state.s_state[PRJQUOTA].blocks;
423 		fqs->qs_pquota.qfs_nextents = state.s_state[PRJQUOTA].nextents;
424 	}
425 	return 0;
426 }
427 
428 static int quota_getxstatev(struct super_block *sb, void __user *addr)
429 {
430 	struct fs_quota_statv fqs;
431 	int ret;
432 
433 	if (!sb->s_qcop->get_state)
434 		return -ENOSYS;
435 
436 	memset(&fqs, 0, sizeof(fqs));
437 	if (copy_from_user(&fqs, addr, 1)) /* Just read qs_version */
438 		return -EFAULT;
439 
440 	/* If this kernel doesn't support user specified version, fail */
441 	switch (fqs.qs_version) {
442 	case FS_QSTATV_VERSION1:
443 		break;
444 	default:
445 		return -EINVAL;
446 	}
447 	ret = quota_getstatev(sb, &fqs);
448 	if (!ret && copy_to_user(addr, &fqs, sizeof(fqs)))
449 		return -EFAULT;
450 	return ret;
451 }
452 
453 /*
454  * XFS defines BBTOB and BTOBB macros inside fs/xfs/ and we cannot move them
455  * out of there as xfsprogs rely on definitions being in that header file. So
456  * just define same functions here for quota purposes.
457  */
458 #define XFS_BB_SHIFT 9
459 
460 static inline u64 quota_bbtob(u64 blocks)
461 {
462 	return blocks << XFS_BB_SHIFT;
463 }
464 
465 static inline u64 quota_btobb(u64 bytes)
466 {
467 	return (bytes + (1 << XFS_BB_SHIFT) - 1) >> XFS_BB_SHIFT;
468 }
469 
470 static void copy_from_xfs_dqblk(struct qc_dqblk *dst, struct fs_disk_quota *src)
471 {
472 	dst->d_spc_hardlimit = quota_bbtob(src->d_blk_hardlimit);
473 	dst->d_spc_softlimit = quota_bbtob(src->d_blk_softlimit);
474 	dst->d_ino_hardlimit = src->d_ino_hardlimit;
475 	dst->d_ino_softlimit = src->d_ino_softlimit;
476 	dst->d_space = quota_bbtob(src->d_bcount);
477 	dst->d_ino_count = src->d_icount;
478 	dst->d_ino_timer = src->d_itimer;
479 	dst->d_spc_timer = src->d_btimer;
480 	dst->d_ino_warns = src->d_iwarns;
481 	dst->d_spc_warns = src->d_bwarns;
482 	dst->d_rt_spc_hardlimit = quota_bbtob(src->d_rtb_hardlimit);
483 	dst->d_rt_spc_softlimit = quota_bbtob(src->d_rtb_softlimit);
484 	dst->d_rt_space = quota_bbtob(src->d_rtbcount);
485 	dst->d_rt_spc_timer = src->d_rtbtimer;
486 	dst->d_rt_spc_warns = src->d_rtbwarns;
487 	dst->d_fieldmask = 0;
488 	if (src->d_fieldmask & FS_DQ_ISOFT)
489 		dst->d_fieldmask |= QC_INO_SOFT;
490 	if (src->d_fieldmask & FS_DQ_IHARD)
491 		dst->d_fieldmask |= QC_INO_HARD;
492 	if (src->d_fieldmask & FS_DQ_BSOFT)
493 		dst->d_fieldmask |= QC_SPC_SOFT;
494 	if (src->d_fieldmask & FS_DQ_BHARD)
495 		dst->d_fieldmask |= QC_SPC_HARD;
496 	if (src->d_fieldmask & FS_DQ_RTBSOFT)
497 		dst->d_fieldmask |= QC_RT_SPC_SOFT;
498 	if (src->d_fieldmask & FS_DQ_RTBHARD)
499 		dst->d_fieldmask |= QC_RT_SPC_HARD;
500 	if (src->d_fieldmask & FS_DQ_BTIMER)
501 		dst->d_fieldmask |= QC_SPC_TIMER;
502 	if (src->d_fieldmask & FS_DQ_ITIMER)
503 		dst->d_fieldmask |= QC_INO_TIMER;
504 	if (src->d_fieldmask & FS_DQ_RTBTIMER)
505 		dst->d_fieldmask |= QC_RT_SPC_TIMER;
506 	if (src->d_fieldmask & FS_DQ_BWARNS)
507 		dst->d_fieldmask |= QC_SPC_WARNS;
508 	if (src->d_fieldmask & FS_DQ_IWARNS)
509 		dst->d_fieldmask |= QC_INO_WARNS;
510 	if (src->d_fieldmask & FS_DQ_RTBWARNS)
511 		dst->d_fieldmask |= QC_RT_SPC_WARNS;
512 	if (src->d_fieldmask & FS_DQ_BCOUNT)
513 		dst->d_fieldmask |= QC_SPACE;
514 	if (src->d_fieldmask & FS_DQ_ICOUNT)
515 		dst->d_fieldmask |= QC_INO_COUNT;
516 	if (src->d_fieldmask & FS_DQ_RTBCOUNT)
517 		dst->d_fieldmask |= QC_RT_SPACE;
518 }
519 
520 static void copy_qcinfo_from_xfs_dqblk(struct qc_info *dst,
521 				       struct fs_disk_quota *src)
522 {
523 	memset(dst, 0, sizeof(*dst));
524 	dst->i_spc_timelimit = src->d_btimer;
525 	dst->i_ino_timelimit = src->d_itimer;
526 	dst->i_rt_spc_timelimit = src->d_rtbtimer;
527 	dst->i_ino_warnlimit = src->d_iwarns;
528 	dst->i_spc_warnlimit = src->d_bwarns;
529 	dst->i_rt_spc_warnlimit = src->d_rtbwarns;
530 	if (src->d_fieldmask & FS_DQ_BWARNS)
531 		dst->i_fieldmask |= QC_SPC_WARNS;
532 	if (src->d_fieldmask & FS_DQ_IWARNS)
533 		dst->i_fieldmask |= QC_INO_WARNS;
534 	if (src->d_fieldmask & FS_DQ_RTBWARNS)
535 		dst->i_fieldmask |= QC_RT_SPC_WARNS;
536 	if (src->d_fieldmask & FS_DQ_BTIMER)
537 		dst->i_fieldmask |= QC_SPC_TIMER;
538 	if (src->d_fieldmask & FS_DQ_ITIMER)
539 		dst->i_fieldmask |= QC_INO_TIMER;
540 	if (src->d_fieldmask & FS_DQ_RTBTIMER)
541 		dst->i_fieldmask |= QC_RT_SPC_TIMER;
542 }
543 
544 static int quota_setxquota(struct super_block *sb, int type, qid_t id,
545 			   void __user *addr)
546 {
547 	struct fs_disk_quota fdq;
548 	struct qc_dqblk qdq;
549 	struct kqid qid;
550 
551 	if (copy_from_user(&fdq, addr, sizeof(fdq)))
552 		return -EFAULT;
553 	if (!sb->s_qcop->set_dqblk)
554 		return -ENOSYS;
555 	qid = make_kqid(current_user_ns(), type, id);
556 	if (!qid_valid(qid))
557 		return -EINVAL;
558 	/* Are we actually setting timer / warning limits for all users? */
559 	if (from_kqid(&init_user_ns, qid) == 0 &&
560 	    fdq.d_fieldmask & (FS_DQ_WARNS_MASK | FS_DQ_TIMER_MASK)) {
561 		struct qc_info qinfo;
562 		int ret;
563 
564 		if (!sb->s_qcop->set_info)
565 			return -EINVAL;
566 		copy_qcinfo_from_xfs_dqblk(&qinfo, &fdq);
567 		ret = sb->s_qcop->set_info(sb, type, &qinfo);
568 		if (ret)
569 			return ret;
570 		/* These are already done */
571 		fdq.d_fieldmask &= ~(FS_DQ_WARNS_MASK | FS_DQ_TIMER_MASK);
572 	}
573 	copy_from_xfs_dqblk(&qdq, &fdq);
574 	return sb->s_qcop->set_dqblk(sb, qid, &qdq);
575 }
576 
577 static void copy_to_xfs_dqblk(struct fs_disk_quota *dst, struct qc_dqblk *src,
578 			      int type, qid_t id)
579 {
580 	memset(dst, 0, sizeof(*dst));
581 	dst->d_version = FS_DQUOT_VERSION;
582 	dst->d_id = id;
583 	if (type == USRQUOTA)
584 		dst->d_flags = FS_USER_QUOTA;
585 	else if (type == PRJQUOTA)
586 		dst->d_flags = FS_PROJ_QUOTA;
587 	else
588 		dst->d_flags = FS_GROUP_QUOTA;
589 	dst->d_blk_hardlimit = quota_btobb(src->d_spc_hardlimit);
590 	dst->d_blk_softlimit = quota_btobb(src->d_spc_softlimit);
591 	dst->d_ino_hardlimit = src->d_ino_hardlimit;
592 	dst->d_ino_softlimit = src->d_ino_softlimit;
593 	dst->d_bcount = quota_btobb(src->d_space);
594 	dst->d_icount = src->d_ino_count;
595 	dst->d_itimer = src->d_ino_timer;
596 	dst->d_btimer = src->d_spc_timer;
597 	dst->d_iwarns = src->d_ino_warns;
598 	dst->d_bwarns = src->d_spc_warns;
599 	dst->d_rtb_hardlimit = quota_btobb(src->d_rt_spc_hardlimit);
600 	dst->d_rtb_softlimit = quota_btobb(src->d_rt_spc_softlimit);
601 	dst->d_rtbcount = quota_btobb(src->d_rt_space);
602 	dst->d_rtbtimer = src->d_rt_spc_timer;
603 	dst->d_rtbwarns = src->d_rt_spc_warns;
604 }
605 
606 static int quota_getxquota(struct super_block *sb, int type, qid_t id,
607 			   void __user *addr)
608 {
609 	struct fs_disk_quota fdq;
610 	struct qc_dqblk qdq;
611 	struct kqid qid;
612 	int ret;
613 
614 	if (!sb->s_qcop->get_dqblk)
615 		return -ENOSYS;
616 	qid = make_kqid(current_user_ns(), type, id);
617 	if (!qid_valid(qid))
618 		return -EINVAL;
619 	ret = sb->s_qcop->get_dqblk(sb, qid, &qdq);
620 	if (ret)
621 		return ret;
622 	copy_to_xfs_dqblk(&fdq, &qdq, type, id);
623 	if (copy_to_user(addr, &fdq, sizeof(fdq)))
624 		return -EFAULT;
625 	return ret;
626 }
627 
628 static int quota_rmxquota(struct super_block *sb, void __user *addr)
629 {
630 	__u32 flags;
631 
632 	if (copy_from_user(&flags, addr, sizeof(flags)))
633 		return -EFAULT;
634 	if (!sb->s_qcop->rm_xquota)
635 		return -ENOSYS;
636 	return sb->s_qcop->rm_xquota(sb, flags);
637 }
638 
639 /* Copy parameters and call proper function */
640 static int do_quotactl(struct super_block *sb, int type, int cmd, qid_t id,
641 		       void __user *addr, struct path *path)
642 {
643 	int ret;
644 
645 	if (type >= (XQM_COMMAND(cmd) ? XQM_MAXQUOTAS : MAXQUOTAS))
646 		return -EINVAL;
647 	/*
648 	 * Quota not supported on this fs? Check this before s_quota_types
649 	 * since they needn't be set if quota is not supported at all.
650 	 */
651 	if (!sb->s_qcop)
652 		return -ENOSYS;
653 	if (!(sb->s_quota_types & (1 << type)))
654 		return -EINVAL;
655 
656 	ret = check_quotactl_permission(sb, type, cmd, id);
657 	if (ret < 0)
658 		return ret;
659 
660 	switch (cmd) {
661 	case Q_QUOTAON:
662 		return quota_quotaon(sb, type, cmd, id, path);
663 	case Q_QUOTAOFF:
664 		return quota_quotaoff(sb, type);
665 	case Q_GETFMT:
666 		return quota_getfmt(sb, type, addr);
667 	case Q_GETINFO:
668 		return quota_getinfo(sb, type, addr);
669 	case Q_SETINFO:
670 		return quota_setinfo(sb, type, addr);
671 	case Q_GETQUOTA:
672 		return quota_getquota(sb, type, id, addr);
673 	case Q_SETQUOTA:
674 		return quota_setquota(sb, type, id, addr);
675 	case Q_SYNC:
676 		if (!sb->s_qcop->quota_sync)
677 			return -ENOSYS;
678 		return sb->s_qcop->quota_sync(sb, type);
679 	case Q_XQUOTAON:
680 		return quota_enable(sb, addr);
681 	case Q_XQUOTAOFF:
682 		return quota_disable(sb, addr);
683 	case Q_XQUOTARM:
684 		return quota_rmxquota(sb, addr);
685 	case Q_XGETQSTAT:
686 		return quota_getxstate(sb, addr);
687 	case Q_XGETQSTATV:
688 		return quota_getxstatev(sb, addr);
689 	case Q_XSETQLIM:
690 		return quota_setxquota(sb, type, id, addr);
691 	case Q_XGETQUOTA:
692 		return quota_getxquota(sb, type, id, addr);
693 	case Q_XQUOTASYNC:
694 		if (sb->s_flags & MS_RDONLY)
695 			return -EROFS;
696 		/* XFS quotas are fully coherent now, making this call a noop */
697 		return 0;
698 	default:
699 		return -EINVAL;
700 	}
701 }
702 
703 #ifdef CONFIG_BLOCK
704 
705 /* Return 1 if 'cmd' will block on frozen filesystem */
706 static int quotactl_cmd_write(int cmd)
707 {
708 	switch (cmd) {
709 	case Q_GETFMT:
710 	case Q_GETINFO:
711 	case Q_SYNC:
712 	case Q_XGETQSTAT:
713 	case Q_XGETQSTATV:
714 	case Q_XGETQUOTA:
715 	case Q_XQUOTASYNC:
716 		return 0;
717 	}
718 	return 1;
719 }
720 
721 #endif /* CONFIG_BLOCK */
722 
723 /*
724  * look up a superblock on which quota ops will be performed
725  * - use the name of a block device to find the superblock thereon
726  */
727 static struct super_block *quotactl_block(const char __user *special, int cmd)
728 {
729 #ifdef CONFIG_BLOCK
730 	struct block_device *bdev;
731 	struct super_block *sb;
732 	struct filename *tmp = getname(special);
733 
734 	if (IS_ERR(tmp))
735 		return ERR_CAST(tmp);
736 	bdev = lookup_bdev(tmp->name);
737 	putname(tmp);
738 	if (IS_ERR(bdev))
739 		return ERR_CAST(bdev);
740 	if (quotactl_cmd_write(cmd))
741 		sb = get_super_thawed(bdev);
742 	else
743 		sb = get_super(bdev);
744 	bdput(bdev);
745 	if (!sb)
746 		return ERR_PTR(-ENODEV);
747 
748 	return sb;
749 #else
750 	return ERR_PTR(-ENODEV);
751 #endif
752 }
753 
754 /*
755  * This is the system call interface. This communicates with
756  * the user-level programs. Currently this only supports diskquota
757  * calls. Maybe we need to add the process quotas etc. in the future,
758  * but we probably should use rlimits for that.
759  */
760 SYSCALL_DEFINE4(quotactl, unsigned int, cmd, const char __user *, special,
761 		qid_t, id, void __user *, addr)
762 {
763 	uint cmds, type;
764 	struct super_block *sb = NULL;
765 	struct path path, *pathp = NULL;
766 	int ret;
767 
768 	cmds = cmd >> SUBCMDSHIFT;
769 	type = cmd & SUBCMDMASK;
770 
771 	/*
772 	 * As a special case Q_SYNC can be called without a specific device.
773 	 * It will iterate all superblocks that have quota enabled and call
774 	 * the sync action on each of them.
775 	 */
776 	if (!special) {
777 		if (cmds == Q_SYNC)
778 			return quota_sync_all(type);
779 		return -ENODEV;
780 	}
781 
782 	/*
783 	 * Path for quotaon has to be resolved before grabbing superblock
784 	 * because that gets s_umount sem which is also possibly needed by path
785 	 * resolution (think about autofs) and thus deadlocks could arise.
786 	 */
787 	if (cmds == Q_QUOTAON) {
788 		ret = user_path_at(AT_FDCWD, addr, LOOKUP_FOLLOW|LOOKUP_AUTOMOUNT, &path);
789 		if (ret)
790 			pathp = ERR_PTR(ret);
791 		else
792 			pathp = &path;
793 	}
794 
795 	sb = quotactl_block(special, cmds);
796 	if (IS_ERR(sb)) {
797 		ret = PTR_ERR(sb);
798 		goto out;
799 	}
800 
801 	ret = do_quotactl(sb, type, cmds, id, addr, pathp);
802 
803 	drop_super(sb);
804 out:
805 	if (pathp && !IS_ERR(pathp))
806 		path_put(pathp);
807 	return ret;
808 }
809