blob: 75621649dbd76dd997aa96462d5d2b6c2124e5a9 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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>
Jeff Liuf3da9312012-05-28 23:40:17 +080012#include <linux/uaccess.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070013#include <linux/kernel.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070014#include <linux/security.h>
15#include <linux/syscalls.h>
Randy Dunlap16f7e0f2006-01-11 12:17:46 -080016#include <linux/capability.h>
Adrian Bunkbe586ba2005-11-07 00:59:35 -080017#include <linux/quotaops.h>
Vasily Tarasovb7163952007-07-15 23:41:12 -070018#include <linux/types.h>
Christoph Hellwig8c4e4ac2010-02-16 03:44:51 -050019#include <linux/writeback.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070020
Christoph Hellwigc988afb2010-02-16 03:44:50 -050021static int check_quotactl_permission(struct super_block *sb, int type, int cmd,
22 qid_t id)
Linus Torvalds1da177e2005-04-16 15:20:36 -070023{
Christoph Hellwigc988afb2010-02-16 03:44:50 -050024 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:
Chandra Seetharamanaf30cb42013-08-06 17:27:07 -050030 case Q_XGETQSTATV:
Christoph Hellwigc988afb2010-02-16 03:44:50 -050031 case Q_XQUOTASYNC:
32 break;
33 /* allow to query information for dquots we "own" */
34 case Q_GETQUOTA:
35 case Q_XGETQUOTA:
Eric W. Biederman74a8a102012-09-16 02:07:49 -070036 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))))
Christoph Hellwigc988afb2010-02-16 03:44:50 -050038 break;
39 /*FALLTHROUGH*/
40 default:
Linus Torvalds1da177e2005-04-16 15:20:36 -070041 if (!capable(CAP_SYS_ADMIN))
42 return -EPERM;
43 }
44
Christoph Hellwigc988afb2010-02-16 03:44:50 -050045 return security_quotactl(cmd, type, id, sb);
Linus Torvalds1da177e2005-04-16 15:20:36 -070046}
47
Al Viro01a05b32010-03-23 06:06:58 -040048static void quota_sync_one(struct super_block *sb, void *arg)
49{
50 if (sb->s_qcop && sb->s_qcop->quota_sync)
Jan Karaceed1722012-07-03 16:45:28 +020051 sb->s_qcop->quota_sync(sb, *(int *)arg);
Al Viro01a05b32010-03-23 06:06:58 -040052}
53
Christoph Hellwig6ae09572010-02-16 03:44:49 -050054static int quota_sync_all(int type)
Linus Torvalds1da177e2005-04-16 15:20:36 -070055{
Christoph Hellwig6ae09572010-02-16 03:44:49 -050056 int ret;
57
58 if (type >= MAXQUOTAS)
59 return -EINVAL;
60 ret = security_quotactl(Q_SYNC, type, 0, NULL);
Al Viro01a05b32010-03-23 06:06:58 -040061 if (!ret)
62 iterate_supers(quota_sync_one, &type);
63 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -070064}
65
Christoph Hellwigc411e5f2010-02-16 03:44:47 -050066static int quota_quotaon(struct super_block *sb, int type, int cmd, qid_t id,
Jan Karaf00c9e42010-09-15 17:38:58 +020067 struct path *path)
Christoph Hellwigc411e5f2010-02-16 03:44:47 -050068{
Jan Karaf00c9e42010-09-15 17:38:58 +020069 if (!sb->s_qcop->quota_on && !sb->s_qcop->quota_on_meta)
70 return -ENOSYS;
71 if (sb->s_qcop->quota_on_meta)
72 return sb->s_qcop->quota_on_meta(sb, type, id);
73 if (IS_ERR(path))
74 return PTR_ERR(path);
75 return sb->s_qcop->quota_on(sb, type, id, path);
Christoph Hellwigc411e5f2010-02-16 03:44:47 -050076}
77
78static int quota_getfmt(struct super_block *sb, int type, void __user *addr)
79{
80 __u32 fmt;
81
Niu Yawei606cdcc2014-06-04 12:19:12 +080082 mutex_lock(&sb_dqopt(sb)->dqonoff_mutex);
Christoph Hellwigc411e5f2010-02-16 03:44:47 -050083 if (!sb_has_quota_active(sb, type)) {
Niu Yawei606cdcc2014-06-04 12:19:12 +080084 mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
Christoph Hellwigc411e5f2010-02-16 03:44:47 -050085 return -ESRCH;
86 }
87 fmt = sb_dqopt(sb)->info[type].dqi_format->qf_fmt_id;
Niu Yawei606cdcc2014-06-04 12:19:12 +080088 mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
Christoph Hellwigc411e5f2010-02-16 03:44:47 -050089 if (copy_to_user(addr, &fmt, sizeof(fmt)))
90 return -EFAULT;
91 return 0;
92}
93
94static int quota_getinfo(struct super_block *sb, int type, void __user *addr)
95{
96 struct if_dqinfo info;
97 int ret;
98
Christoph Hellwigf450d4f2010-02-16 03:44:48 -050099 if (!sb->s_qcop->get_info)
100 return -ENOSYS;
Christoph Hellwigc411e5f2010-02-16 03:44:47 -0500101 ret = sb->s_qcop->get_info(sb, type, &info);
102 if (!ret && copy_to_user(addr, &info, sizeof(info)))
103 return -EFAULT;
104 return ret;
105}
106
107static int quota_setinfo(struct super_block *sb, int type, void __user *addr)
108{
109 struct if_dqinfo info;
110
111 if (copy_from_user(&info, addr, sizeof(info)))
112 return -EFAULT;
Christoph Hellwigf450d4f2010-02-16 03:44:48 -0500113 if (!sb->s_qcop->set_info)
114 return -ENOSYS;
Christoph Hellwigc411e5f2010-02-16 03:44:47 -0500115 return sb->s_qcop->set_info(sb, type, &info);
116}
117
Christoph Hellwigb9b2dd32010-05-06 17:04:58 -0400118static void copy_to_if_dqblk(struct if_dqblk *dst, struct fs_disk_quota *src)
119{
Dan Carpenter18da65e2013-11-01 13:21:54 +0300120 memset(dst, 0, sizeof(*dst));
Christoph Hellwigb9b2dd32010-05-06 17:04:58 -0400121 dst->dqb_bhardlimit = src->d_blk_hardlimit;
122 dst->dqb_bsoftlimit = src->d_blk_softlimit;
123 dst->dqb_curspace = src->d_bcount;
124 dst->dqb_ihardlimit = src->d_ino_hardlimit;
125 dst->dqb_isoftlimit = src->d_ino_softlimit;
126 dst->dqb_curinodes = src->d_icount;
127 dst->dqb_btime = src->d_btimer;
128 dst->dqb_itime = src->d_itimer;
129 dst->dqb_valid = QIF_ALL;
130}
131
Christoph Hellwigc411e5f2010-02-16 03:44:47 -0500132static int quota_getquota(struct super_block *sb, int type, qid_t id,
133 void __user *addr)
134{
Eric W. Biederman74a8a102012-09-16 02:07:49 -0700135 struct kqid qid;
Christoph Hellwigb9b2dd32010-05-06 17:04:58 -0400136 struct fs_disk_quota fdq;
Christoph Hellwigc411e5f2010-02-16 03:44:47 -0500137 struct if_dqblk idq;
138 int ret;
139
Christoph Hellwigf450d4f2010-02-16 03:44:48 -0500140 if (!sb->s_qcop->get_dqblk)
141 return -ENOSYS;
Eric W. Biederman74a8a102012-09-16 02:07:49 -0700142 qid = make_kqid(current_user_ns(), type, id);
143 if (!qid_valid(qid))
144 return -EINVAL;
145 ret = sb->s_qcop->get_dqblk(sb, qid, &fdq);
Christoph Hellwigc411e5f2010-02-16 03:44:47 -0500146 if (ret)
147 return ret;
Christoph Hellwigb9b2dd32010-05-06 17:04:58 -0400148 copy_to_if_dqblk(&idq, &fdq);
Christoph Hellwigc411e5f2010-02-16 03:44:47 -0500149 if (copy_to_user(addr, &idq, sizeof(idq)))
150 return -EFAULT;
151 return 0;
152}
153
Christoph Hellwigc472b432010-05-06 17:05:17 -0400154static void copy_from_if_dqblk(struct fs_disk_quota *dst, struct if_dqblk *src)
155{
156 dst->d_blk_hardlimit = src->dqb_bhardlimit;
157 dst->d_blk_softlimit = src->dqb_bsoftlimit;
158 dst->d_bcount = src->dqb_curspace;
159 dst->d_ino_hardlimit = src->dqb_ihardlimit;
160 dst->d_ino_softlimit = src->dqb_isoftlimit;
161 dst->d_icount = src->dqb_curinodes;
162 dst->d_btimer = src->dqb_btime;
163 dst->d_itimer = src->dqb_itime;
164
165 dst->d_fieldmask = 0;
166 if (src->dqb_valid & QIF_BLIMITS)
167 dst->d_fieldmask |= FS_DQ_BSOFT | FS_DQ_BHARD;
168 if (src->dqb_valid & QIF_SPACE)
169 dst->d_fieldmask |= FS_DQ_BCOUNT;
170 if (src->dqb_valid & QIF_ILIMITS)
171 dst->d_fieldmask |= FS_DQ_ISOFT | FS_DQ_IHARD;
172 if (src->dqb_valid & QIF_INODES)
173 dst->d_fieldmask |= FS_DQ_ICOUNT;
174 if (src->dqb_valid & QIF_BTIME)
175 dst->d_fieldmask |= FS_DQ_BTIMER;
176 if (src->dqb_valid & QIF_ITIME)
177 dst->d_fieldmask |= FS_DQ_ITIMER;
178}
179
Christoph Hellwigc411e5f2010-02-16 03:44:47 -0500180static int quota_setquota(struct super_block *sb, int type, qid_t id,
181 void __user *addr)
182{
Christoph Hellwigc472b432010-05-06 17:05:17 -0400183 struct fs_disk_quota fdq;
Christoph Hellwigc411e5f2010-02-16 03:44:47 -0500184 struct if_dqblk idq;
Eric W. Biederman74a8a102012-09-16 02:07:49 -0700185 struct kqid qid;
Christoph Hellwigc411e5f2010-02-16 03:44:47 -0500186
187 if (copy_from_user(&idq, addr, sizeof(idq)))
188 return -EFAULT;
Christoph Hellwigf450d4f2010-02-16 03:44:48 -0500189 if (!sb->s_qcop->set_dqblk)
190 return -ENOSYS;
Eric W. Biederman74a8a102012-09-16 02:07:49 -0700191 qid = make_kqid(current_user_ns(), type, id);
192 if (!qid_valid(qid))
193 return -EINVAL;
Christoph Hellwigc472b432010-05-06 17:05:17 -0400194 copy_from_if_dqblk(&fdq, &idq);
Eric W. Biederman74a8a102012-09-16 02:07:49 -0700195 return sb->s_qcop->set_dqblk(sb, qid, &fdq);
Christoph Hellwigc411e5f2010-02-16 03:44:47 -0500196}
197
198static int quota_setxstate(struct super_block *sb, int cmd, void __user *addr)
199{
200 __u32 flags;
201
202 if (copy_from_user(&flags, addr, sizeof(flags)))
203 return -EFAULT;
Christoph Hellwigf450d4f2010-02-16 03:44:48 -0500204 if (!sb->s_qcop->set_xstate)
205 return -ENOSYS;
Christoph Hellwigc411e5f2010-02-16 03:44:47 -0500206 return sb->s_qcop->set_xstate(sb, flags, cmd);
207}
208
209static int quota_getxstate(struct super_block *sb, void __user *addr)
210{
211 struct fs_quota_stat fqs;
212 int ret;
Christoph Hellwigf450d4f2010-02-16 03:44:48 -0500213
214 if (!sb->s_qcop->get_xstate)
215 return -ENOSYS;
Christoph Hellwigc411e5f2010-02-16 03:44:47 -0500216 ret = sb->s_qcop->get_xstate(sb, &fqs);
217 if (!ret && copy_to_user(addr, &fqs, sizeof(fqs)))
218 return -EFAULT;
219 return ret;
220}
221
Chandra Seetharamanaf30cb42013-08-06 17:27:07 -0500222static int quota_getxstatev(struct super_block *sb, void __user *addr)
223{
224 struct fs_quota_statv fqs;
225 int ret;
226
227 if (!sb->s_qcop->get_xstatev)
228 return -ENOSYS;
229
230 memset(&fqs, 0, sizeof(fqs));
231 if (copy_from_user(&fqs, addr, 1)) /* Just read qs_version */
232 return -EFAULT;
233
234 /* If this kernel doesn't support user specified version, fail */
235 switch (fqs.qs_version) {
236 case FS_QSTATV_VERSION1:
237 break;
238 default:
239 return -EINVAL;
240 }
241 ret = sb->s_qcop->get_xstatev(sb, &fqs);
242 if (!ret && copy_to_user(addr, &fqs, sizeof(fqs)))
243 return -EFAULT;
244 return ret;
245}
246
Christoph Hellwigc411e5f2010-02-16 03:44:47 -0500247static int quota_setxquota(struct super_block *sb, int type, qid_t id,
248 void __user *addr)
249{
250 struct fs_disk_quota fdq;
Eric W. Biederman74a8a102012-09-16 02:07:49 -0700251 struct kqid qid;
Christoph Hellwigc411e5f2010-02-16 03:44:47 -0500252
253 if (copy_from_user(&fdq, addr, sizeof(fdq)))
254 return -EFAULT;
Christoph Hellwigc472b432010-05-06 17:05:17 -0400255 if (!sb->s_qcop->set_dqblk)
Christoph Hellwigf450d4f2010-02-16 03:44:48 -0500256 return -ENOSYS;
Eric W. Biederman74a8a102012-09-16 02:07:49 -0700257 qid = make_kqid(current_user_ns(), type, id);
258 if (!qid_valid(qid))
259 return -EINVAL;
260 return sb->s_qcop->set_dqblk(sb, qid, &fdq);
Christoph Hellwigc411e5f2010-02-16 03:44:47 -0500261}
262
263static int quota_getxquota(struct super_block *sb, int type, qid_t id,
264 void __user *addr)
265{
266 struct fs_disk_quota fdq;
Eric W. Biederman74a8a102012-09-16 02:07:49 -0700267 struct kqid qid;
Christoph Hellwigc411e5f2010-02-16 03:44:47 -0500268 int ret;
269
Christoph Hellwigb9b2dd32010-05-06 17:04:58 -0400270 if (!sb->s_qcop->get_dqblk)
Christoph Hellwigf450d4f2010-02-16 03:44:48 -0500271 return -ENOSYS;
Eric W. Biederman74a8a102012-09-16 02:07:49 -0700272 qid = make_kqid(current_user_ns(), type, id);
273 if (!qid_valid(qid))
274 return -EINVAL;
275 ret = sb->s_qcop->get_dqblk(sb, qid, &fdq);
Christoph Hellwigc411e5f2010-02-16 03:44:47 -0500276 if (!ret && copy_to_user(addr, &fdq, sizeof(fdq)))
277 return -EFAULT;
278 return ret;
279}
280
Eric Sandeen9da93f92014-05-05 17:25:50 +1000281static int quota_rmxquota(struct super_block *sb, void __user *addr)
282{
283 __u32 flags;
284
285 if (copy_from_user(&flags, addr, sizeof(flags)))
286 return -EFAULT;
287 if (!sb->s_qcop->rm_xquota)
288 return -ENOSYS;
289 return sb->s_qcop->rm_xquota(sb, flags);
290}
291
Linus Torvalds1da177e2005-04-16 15:20:36 -0700292/* Copy parameters and call proper function */
Jan Kara268157b2009-01-27 15:47:22 +0100293static int do_quotactl(struct super_block *sb, int type, int cmd, qid_t id,
Jan Karaf00c9e42010-09-15 17:38:58 +0200294 void __user *addr, struct path *path)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700295{
Christoph Hellwigc988afb2010-02-16 03:44:50 -0500296 int ret;
297
298 if (type >= (XQM_COMMAND(cmd) ? XQM_MAXQUOTAS : MAXQUOTAS))
299 return -EINVAL;
300 if (!sb->s_qcop)
301 return -ENOSYS;
302
303 ret = check_quotactl_permission(sb, type, cmd, id);
304 if (ret < 0)
305 return ret;
306
Linus Torvalds1da177e2005-04-16 15:20:36 -0700307 switch (cmd) {
Christoph Hellwigc411e5f2010-02-16 03:44:47 -0500308 case Q_QUOTAON:
Jan Karaf00c9e42010-09-15 17:38:58 +0200309 return quota_quotaon(sb, type, cmd, id, path);
Christoph Hellwigc411e5f2010-02-16 03:44:47 -0500310 case Q_QUOTAOFF:
Christoph Hellwigf450d4f2010-02-16 03:44:48 -0500311 if (!sb->s_qcop->quota_off)
312 return -ENOSYS;
Christoph Hellwig307ae182010-05-19 07:16:43 -0400313 return sb->s_qcop->quota_off(sb, type);
Christoph Hellwigc411e5f2010-02-16 03:44:47 -0500314 case Q_GETFMT:
315 return quota_getfmt(sb, type, addr);
316 case Q_GETINFO:
317 return quota_getinfo(sb, type, addr);
318 case Q_SETINFO:
319 return quota_setinfo(sb, type, addr);
320 case Q_GETQUOTA:
321 return quota_getquota(sb, type, id, addr);
322 case Q_SETQUOTA:
323 return quota_setquota(sb, type, id, addr);
324 case Q_SYNC:
Christoph Hellwig6ae09572010-02-16 03:44:49 -0500325 if (!sb->s_qcop->quota_sync)
326 return -ENOSYS;
Jan Karaceed1722012-07-03 16:45:28 +0200327 return sb->s_qcop->quota_sync(sb, type);
Christoph Hellwigc411e5f2010-02-16 03:44:47 -0500328 case Q_XQUOTAON:
329 case Q_XQUOTAOFF:
Christoph Hellwigc411e5f2010-02-16 03:44:47 -0500330 return quota_setxstate(sb, cmd, addr);
Eric Sandeen9da93f92014-05-05 17:25:50 +1000331 case Q_XQUOTARM:
332 return quota_rmxquota(sb, addr);
Christoph Hellwigc411e5f2010-02-16 03:44:47 -0500333 case Q_XGETQSTAT:
334 return quota_getxstate(sb, addr);
Chandra Seetharamanaf30cb42013-08-06 17:27:07 -0500335 case Q_XGETQSTATV:
336 return quota_getxstatev(sb, addr);
Christoph Hellwigc411e5f2010-02-16 03:44:47 -0500337 case Q_XSETQLIM:
338 return quota_setxquota(sb, type, id, addr);
339 case Q_XGETQUOTA:
340 return quota_getxquota(sb, type, id, addr);
341 case Q_XQUOTASYNC:
Christoph Hellwig8c4e4ac2010-02-16 03:44:51 -0500342 if (sb->s_flags & MS_RDONLY)
343 return -EROFS;
Christoph Hellwig4b217ed2012-02-20 02:28:18 +0000344 /* XFS quotas are fully coherent now, making this call a noop */
Christoph Hellwig8c4e4ac2010-02-16 03:44:51 -0500345 return 0;
Christoph Hellwigc411e5f2010-02-16 03:44:47 -0500346 default:
Christoph Hellwigf450d4f2010-02-16 03:44:48 -0500347 return -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700348 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700349}
350
Lee Jones56df1272012-11-03 23:02:28 +0100351#ifdef CONFIG_BLOCK
352
Jan Karadcdbed82012-02-10 11:03:01 +0100353/* Return 1 if 'cmd' will block on frozen filesystem */
354static int quotactl_cmd_write(int cmd)
355{
356 switch (cmd) {
357 case Q_GETFMT:
358 case Q_GETINFO:
359 case Q_SYNC:
360 case Q_XGETQSTAT:
Chandra Seetharamanaf30cb42013-08-06 17:27:07 -0500361 case Q_XGETQSTATV:
Jan Karadcdbed82012-02-10 11:03:01 +0100362 case Q_XGETQUOTA:
363 case Q_XQUOTASYNC:
364 return 0;
365 }
366 return 1;
367}
368
Lee Jones56df1272012-11-03 23:02:28 +0100369#endif /* CONFIG_BLOCK */
370
Linus Torvalds1da177e2005-04-16 15:20:36 -0700371/*
David Howells93614012006-09-30 20:45:40 +0200372 * look up a superblock on which quota ops will be performed
373 * - use the name of a block device to find the superblock thereon
374 */
Jan Karadcdbed82012-02-10 11:03:01 +0100375static struct super_block *quotactl_block(const char __user *special, int cmd)
David Howells93614012006-09-30 20:45:40 +0200376{
377#ifdef CONFIG_BLOCK
378 struct block_device *bdev;
379 struct super_block *sb;
Jeff Layton91a27b22012-10-10 15:25:28 -0400380 struct filename *tmp = getname(special);
David Howells93614012006-09-30 20:45:40 +0200381
382 if (IS_ERR(tmp))
David Howellse231c2e2008-02-07 00:15:26 -0800383 return ERR_CAST(tmp);
Jeff Layton91a27b22012-10-10 15:25:28 -0400384 bdev = lookup_bdev(tmp->name);
David Howells93614012006-09-30 20:45:40 +0200385 putname(tmp);
386 if (IS_ERR(bdev))
David Howellse231c2e2008-02-07 00:15:26 -0800387 return ERR_CAST(bdev);
Jan Karadcdbed82012-02-10 11:03:01 +0100388 if (quotactl_cmd_write(cmd))
389 sb = get_super_thawed(bdev);
390 else
391 sb = get_super(bdev);
David Howells93614012006-09-30 20:45:40 +0200392 bdput(bdev);
393 if (!sb)
394 return ERR_PTR(-ENODEV);
395
396 return sb;
397#else
398 return ERR_PTR(-ENODEV);
399#endif
400}
401
402/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700403 * This is the system call interface. This communicates with
404 * the user-level programs. Currently this only supports diskquota
405 * calls. Maybe we need to add the process quotas etc. in the future,
406 * but we probably should use rlimits for that.
407 */
Heiko Carstens3cdad422009-01-14 14:14:22 +0100408SYSCALL_DEFINE4(quotactl, unsigned int, cmd, const char __user *, special,
409 qid_t, id, void __user *, addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700410{
411 uint cmds, type;
412 struct super_block *sb = NULL;
Jan Karaf00c9e42010-09-15 17:38:58 +0200413 struct path path, *pathp = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700414 int ret;
415
416 cmds = cmd >> SUBCMDSHIFT;
417 type = cmd & SUBCMDMASK;
418
Christoph Hellwig6ae09572010-02-16 03:44:49 -0500419 /*
420 * As a special case Q_SYNC can be called without a specific device.
421 * It will iterate all superblocks that have quota enabled and call
422 * the sync action on each of them.
423 */
424 if (!special) {
425 if (cmds == Q_SYNC)
426 return quota_sync_all(type);
427 return -ENODEV;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700428 }
429
Jan Karaf00c9e42010-09-15 17:38:58 +0200430 /*
431 * Path for quotaon has to be resolved before grabbing superblock
432 * because that gets s_umount sem which is also possibly needed by path
433 * resolution (think about autofs) and thus deadlocks could arise.
434 */
435 if (cmds == Q_QUOTAON) {
Trond Myklebust815d4052011-09-26 20:36:09 -0400436 ret = user_path_at(AT_FDCWD, addr, LOOKUP_FOLLOW|LOOKUP_AUTOMOUNT, &path);
Jan Karaf00c9e42010-09-15 17:38:58 +0200437 if (ret)
438 pathp = ERR_PTR(ret);
439 else
440 pathp = &path;
441 }
442
Jan Karadcdbed82012-02-10 11:03:01 +0100443 sb = quotactl_block(special, cmds);
Jan Kara0aaa6182011-10-10 18:32:06 +0200444 if (IS_ERR(sb)) {
445 ret = PTR_ERR(sb);
446 goto out;
447 }
Christoph Hellwig6ae09572010-02-16 03:44:49 -0500448
Jan Karaf00c9e42010-09-15 17:38:58 +0200449 ret = do_quotactl(sb, type, cmds, id, addr, pathp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700450
Christoph Hellwig6ae09572010-02-16 03:44:49 -0500451 drop_super(sb);
Jan Kara0aaa6182011-10-10 18:32:06 +0200452out:
Jan Karaf00c9e42010-09-15 17:38:58 +0200453 if (pathp && !IS_ERR(pathp))
454 path_put(pathp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700455 return ret;
456}