ia64/linux-2.6.18-xen.hg

view fs/quota.c @ 524:7f8b544237bf

netfront: Allow netfront in domain 0.

This is useful if your physical network device is in a utility domain.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
author Keir Fraser <keir.fraser@citrix.com>
date Tue Apr 15 15:18:58 2008 +0100 (2008-04-15)
parents 831230e53067
children
line source
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 */
8 #include <linux/fs.h>
9 #include <linux/namei.h>
10 #include <linux/slab.h>
11 #include <asm/current.h>
12 #include <asm/uaccess.h>
13 #include <linux/kernel.h>
14 #include <linux/smp_lock.h>
15 #include <linux/security.h>
16 #include <linux/syscalls.h>
17 #include <linux/buffer_head.h>
18 #include <linux/capability.h>
19 #include <linux/quotaops.h>
21 /* Check validity of generic quotactl commands */
22 static int generic_quotactl_valid(struct super_block *sb, int type, int cmd, qid_t id)
23 {
24 if (type >= MAXQUOTAS)
25 return -EINVAL;
26 if (!sb && cmd != Q_SYNC)
27 return -ENODEV;
28 /* Is operation supported? */
29 if (sb && !sb->s_qcop)
30 return -ENOSYS;
32 switch (cmd) {
33 case Q_GETFMT:
34 break;
35 case Q_QUOTAON:
36 if (!sb->s_qcop->quota_on)
37 return -ENOSYS;
38 break;
39 case Q_QUOTAOFF:
40 if (!sb->s_qcop->quota_off)
41 return -ENOSYS;
42 break;
43 case Q_SETINFO:
44 if (!sb->s_qcop->set_info)
45 return -ENOSYS;
46 break;
47 case Q_GETINFO:
48 if (!sb->s_qcop->get_info)
49 return -ENOSYS;
50 break;
51 case Q_SETQUOTA:
52 if (!sb->s_qcop->set_dqblk)
53 return -ENOSYS;
54 break;
55 case Q_GETQUOTA:
56 if (!sb->s_qcop->get_dqblk)
57 return -ENOSYS;
58 break;
59 case Q_SYNC:
60 if (sb && !sb->s_qcop->quota_sync)
61 return -ENOSYS;
62 break;
63 default:
64 return -EINVAL;
65 }
67 /* Is quota turned on for commands which need it? */
68 switch (cmd) {
69 case Q_GETFMT:
70 case Q_GETINFO:
71 case Q_QUOTAOFF:
72 case Q_SETINFO:
73 case Q_SETQUOTA:
74 case Q_GETQUOTA:
75 /* This is just informative test so we are satisfied without a lock */
76 if (!sb_has_quota_enabled(sb, type))
77 return -ESRCH;
78 }
80 /* Check privileges */
81 if (cmd == Q_GETQUOTA) {
82 if (((type == USRQUOTA && current->euid != id) ||
83 (type == GRPQUOTA && !in_egroup_p(id))) &&
84 !capable(CAP_SYS_ADMIN))
85 return -EPERM;
86 }
87 else if (cmd != Q_GETFMT && cmd != Q_SYNC && cmd != Q_GETINFO)
88 if (!capable(CAP_SYS_ADMIN))
89 return -EPERM;
91 return 0;
92 }
94 /* Check validity of XFS Quota Manager commands */
95 static int xqm_quotactl_valid(struct super_block *sb, int type, int cmd, qid_t id)
96 {
97 if (type >= XQM_MAXQUOTAS)
98 return -EINVAL;
99 if (!sb)
100 return -ENODEV;
101 if (!sb->s_qcop)
102 return -ENOSYS;
104 switch (cmd) {
105 case Q_XQUOTAON:
106 case Q_XQUOTAOFF:
107 case Q_XQUOTARM:
108 if (!sb->s_qcop->set_xstate)
109 return -ENOSYS;
110 break;
111 case Q_XGETQSTAT:
112 if (!sb->s_qcop->get_xstate)
113 return -ENOSYS;
114 break;
115 case Q_XSETQLIM:
116 if (!sb->s_qcop->set_xquota)
117 return -ENOSYS;
118 break;
119 case Q_XGETQUOTA:
120 if (!sb->s_qcop->get_xquota)
121 return -ENOSYS;
122 break;
123 case Q_XQUOTASYNC:
124 if (!sb->s_qcop->quota_sync)
125 return -ENOSYS;
126 break;
127 default:
128 return -EINVAL;
129 }
131 /* Check privileges */
132 if (cmd == Q_XGETQUOTA) {
133 if (((type == XQM_USRQUOTA && current->euid != id) ||
134 (type == XQM_GRPQUOTA && !in_egroup_p(id))) &&
135 !capable(CAP_SYS_ADMIN))
136 return -EPERM;
137 } else if (cmd != Q_XGETQSTAT && cmd != Q_XQUOTASYNC) {
138 if (!capable(CAP_SYS_ADMIN))
139 return -EPERM;
140 }
142 return 0;
143 }
145 static int check_quotactl_valid(struct super_block *sb, int type, int cmd, qid_t id)
146 {
147 int error;
149 if (XQM_COMMAND(cmd))
150 error = xqm_quotactl_valid(sb, type, cmd, id);
151 else
152 error = generic_quotactl_valid(sb, type, cmd, id);
153 if (!error)
154 error = security_quotactl(cmd, type, id, sb);
155 return error;
156 }
158 static void quota_sync_sb(struct super_block *sb, int type)
159 {
160 int cnt;
161 struct inode *discard[MAXQUOTAS];
163 sb->s_qcop->quota_sync(sb, type);
164 /* This is not very clever (and fast) but currently I don't know about
165 * any other simple way of getting quota data to disk and we must get
166 * them there for userspace to be visible... */
167 if (sb->s_op->sync_fs)
168 sb->s_op->sync_fs(sb, 1);
169 sync_blockdev(sb->s_bdev);
171 /* Now when everything is written we can discard the pagecache so
172 * that userspace sees the changes. We need i_mutex and so we could
173 * not do it inside dqonoff_mutex. Moreover we need to be carefull
174 * about races with quotaoff() (that is the reason why we have own
175 * reference to inode). */
176 mutex_lock(&sb_dqopt(sb)->dqonoff_mutex);
177 for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
178 discard[cnt] = NULL;
179 if (type != -1 && cnt != type)
180 continue;
181 if (!sb_has_quota_enabled(sb, cnt))
182 continue;
183 discard[cnt] = igrab(sb_dqopt(sb)->files[cnt]);
184 }
185 mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
186 for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
187 if (discard[cnt]) {
188 mutex_lock(&discard[cnt]->i_mutex);
189 truncate_inode_pages(&discard[cnt]->i_data, 0);
190 mutex_unlock(&discard[cnt]->i_mutex);
191 iput(discard[cnt]);
192 }
193 }
194 }
196 void sync_dquots(struct super_block *sb, int type)
197 {
198 int cnt, dirty;
200 if (sb) {
201 if (sb->s_qcop->quota_sync)
202 quota_sync_sb(sb, type);
203 return;
204 }
206 spin_lock(&sb_lock);
207 restart:
208 list_for_each_entry(sb, &super_blocks, s_list) {
209 /* This test just improves performance so it needn't be reliable... */
210 for (cnt = 0, dirty = 0; cnt < MAXQUOTAS; cnt++)
211 if ((type == cnt || type == -1) && sb_has_quota_enabled(sb, cnt)
212 && info_any_dirty(&sb_dqopt(sb)->info[cnt]))
213 dirty = 1;
214 if (!dirty)
215 continue;
216 sb->s_count++;
217 spin_unlock(&sb_lock);
218 down_read(&sb->s_umount);
219 if (sb->s_root && sb->s_qcop->quota_sync)
220 quota_sync_sb(sb, type);
221 up_read(&sb->s_umount);
222 spin_lock(&sb_lock);
223 if (__put_super_and_need_restart(sb))
224 goto restart;
225 }
226 spin_unlock(&sb_lock);
227 }
229 /* Copy parameters and call proper function */
230 static int do_quotactl(struct super_block *sb, int type, int cmd, qid_t id, void __user *addr)
231 {
232 int ret;
234 switch (cmd) {
235 case Q_QUOTAON: {
236 char *pathname;
238 if (IS_ERR(pathname = getname(addr)))
239 return PTR_ERR(pathname);
240 ret = sb->s_qcop->quota_on(sb, type, id, pathname);
241 putname(pathname);
242 return ret;
243 }
244 case Q_QUOTAOFF:
245 return sb->s_qcop->quota_off(sb, type);
247 case Q_GETFMT: {
248 __u32 fmt;
250 down_read(&sb_dqopt(sb)->dqptr_sem);
251 if (!sb_has_quota_enabled(sb, type)) {
252 up_read(&sb_dqopt(sb)->dqptr_sem);
253 return -ESRCH;
254 }
255 fmt = sb_dqopt(sb)->info[type].dqi_format->qf_fmt_id;
256 up_read(&sb_dqopt(sb)->dqptr_sem);
257 if (copy_to_user(addr, &fmt, sizeof(fmt)))
258 return -EFAULT;
259 return 0;
260 }
261 case Q_GETINFO: {
262 struct if_dqinfo info;
264 if ((ret = sb->s_qcop->get_info(sb, type, &info)))
265 return ret;
266 if (copy_to_user(addr, &info, sizeof(info)))
267 return -EFAULT;
268 return 0;
269 }
270 case Q_SETINFO: {
271 struct if_dqinfo info;
273 if (copy_from_user(&info, addr, sizeof(info)))
274 return -EFAULT;
275 return sb->s_qcop->set_info(sb, type, &info);
276 }
277 case Q_GETQUOTA: {
278 struct if_dqblk idq;
280 if ((ret = sb->s_qcop->get_dqblk(sb, type, id, &idq)))
281 return ret;
282 if (copy_to_user(addr, &idq, sizeof(idq)))
283 return -EFAULT;
284 return 0;
285 }
286 case Q_SETQUOTA: {
287 struct if_dqblk idq;
289 if (copy_from_user(&idq, addr, sizeof(idq)))
290 return -EFAULT;
291 return sb->s_qcop->set_dqblk(sb, type, id, &idq);
292 }
293 case Q_SYNC:
294 sync_dquots(sb, type);
295 return 0;
297 case Q_XQUOTAON:
298 case Q_XQUOTAOFF:
299 case Q_XQUOTARM: {
300 __u32 flags;
302 if (copy_from_user(&flags, addr, sizeof(flags)))
303 return -EFAULT;
304 return sb->s_qcop->set_xstate(sb, flags, cmd);
305 }
306 case Q_XGETQSTAT: {
307 struct fs_quota_stat fqs;
309 if ((ret = sb->s_qcop->get_xstate(sb, &fqs)))
310 return ret;
311 if (copy_to_user(addr, &fqs, sizeof(fqs)))
312 return -EFAULT;
313 return 0;
314 }
315 case Q_XSETQLIM: {
316 struct fs_disk_quota fdq;
318 if (copy_from_user(&fdq, addr, sizeof(fdq)))
319 return -EFAULT;
320 return sb->s_qcop->set_xquota(sb, type, id, &fdq);
321 }
322 case Q_XGETQUOTA: {
323 struct fs_disk_quota fdq;
325 if ((ret = sb->s_qcop->get_xquota(sb, type, id, &fdq)))
326 return ret;
327 if (copy_to_user(addr, &fdq, sizeof(fdq)))
328 return -EFAULT;
329 return 0;
330 }
331 case Q_XQUOTASYNC:
332 return sb->s_qcop->quota_sync(sb, type);
333 /* We never reach here unless validity check is broken */
334 default:
335 BUG();
336 }
337 return 0;
338 }
340 /*
341 * This is the system call interface. This communicates with
342 * the user-level programs. Currently this only supports diskquota
343 * calls. Maybe we need to add the process quotas etc. in the future,
344 * but we probably should use rlimits for that.
345 */
346 asmlinkage long sys_quotactl(unsigned int cmd, const char __user *special, qid_t id, void __user *addr)
347 {
348 uint cmds, type;
349 struct super_block *sb = NULL;
350 struct block_device *bdev;
351 char *tmp;
352 int ret;
354 cmds = cmd >> SUBCMDSHIFT;
355 type = cmd & SUBCMDMASK;
357 if (cmds != Q_SYNC || special) {
358 tmp = getname(special);
359 if (IS_ERR(tmp))
360 return PTR_ERR(tmp);
361 bdev = lookup_bdev(tmp);
362 putname(tmp);
363 if (IS_ERR(bdev))
364 return PTR_ERR(bdev);
365 sb = get_super(bdev);
366 bdput(bdev);
367 if (!sb)
368 return -ENODEV;
369 }
371 ret = check_quotactl_valid(sb, type, cmds, id);
372 if (ret >= 0)
373 ret = do_quotactl(sb, type, cmds, id, addr);
374 if (sb)
375 drop_super(sb);
377 return ret;
378 }