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git.proxmox.com Git - mirror_ubuntu-bionic-kernel.git/blob - fs/quota.c
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.
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/security.h>
15 #include <linux/syscalls.h>
16 #include <linux/buffer_head.h>
17 #include <linux/capability.h>
18 #include <linux/quotaops.h>
20 /* Check validity of generic quotactl commands */
21 static int generic_quotactl_valid(struct super_block
*sb
, int type
, int cmd
, qid_t id
)
23 if (type
>= MAXQUOTAS
)
25 if (!sb
&& cmd
!= Q_SYNC
)
27 /* Is operation supported? */
28 if (sb
&& !sb
->s_qcop
)
35 if (!sb
->s_qcop
->quota_on
)
39 if (!sb
->s_qcop
->quota_off
)
43 if (!sb
->s_qcop
->set_info
)
47 if (!sb
->s_qcop
->get_info
)
51 if (!sb
->s_qcop
->set_dqblk
)
55 if (!sb
->s_qcop
->get_dqblk
)
59 if (sb
&& !sb
->s_qcop
->quota_sync
)
66 /* Is quota turned on for commands which need it? */
74 /* This is just informative test so we are satisfied without a lock */
75 if (!sb_has_quota_enabled(sb
, type
))
79 /* Check privileges */
80 if (cmd
== Q_GETQUOTA
) {
81 if (((type
== USRQUOTA
&& current
->euid
!= id
) ||
82 (type
== GRPQUOTA
&& !in_egroup_p(id
))) &&
83 !capable(CAP_SYS_ADMIN
))
86 else if (cmd
!= Q_GETFMT
&& cmd
!= Q_SYNC
&& cmd
!= Q_GETINFO
)
87 if (!capable(CAP_SYS_ADMIN
))
93 /* Check validity of XFS Quota Manager commands */
94 static int xqm_quotactl_valid(struct super_block
*sb
, int type
, int cmd
, qid_t id
)
96 if (type
>= XQM_MAXQUOTAS
)
107 if (!sb
->s_qcop
->set_xstate
)
111 if (!sb
->s_qcop
->get_xstate
)
115 if (!sb
->s_qcop
->set_xquota
)
119 if (!sb
->s_qcop
->get_xquota
)
123 if (!sb
->s_qcop
->quota_sync
)
130 /* Check privileges */
131 if (cmd
== Q_XGETQUOTA
) {
132 if (((type
== XQM_USRQUOTA
&& current
->euid
!= id
) ||
133 (type
== XQM_GRPQUOTA
&& !in_egroup_p(id
))) &&
134 !capable(CAP_SYS_ADMIN
))
136 } else if (cmd
!= Q_XGETQSTAT
&& cmd
!= Q_XQUOTASYNC
) {
137 if (!capable(CAP_SYS_ADMIN
))
144 static int check_quotactl_valid(struct super_block
*sb
, int type
, int cmd
, qid_t id
)
148 if (XQM_COMMAND(cmd
))
149 error
= xqm_quotactl_valid(sb
, type
, cmd
, id
);
151 error
= generic_quotactl_valid(sb
, type
, cmd
, id
);
153 error
= security_quotactl(cmd
, type
, id
, sb
);
157 static void quota_sync_sb(struct super_block
*sb
, int type
)
161 sb
->s_qcop
->quota_sync(sb
, type
);
162 /* This is not very clever (and fast) but currently I don't know about
163 * any other simple way of getting quota data to disk and we must get
164 * them there for userspace to be visible... */
165 if (sb
->s_op
->sync_fs
)
166 sb
->s_op
->sync_fs(sb
, 1);
167 sync_blockdev(sb
->s_bdev
);
170 * Now when everything is written we can discard the pagecache so
171 * that userspace sees the changes.
173 mutex_lock(&sb_dqopt(sb
)->dqonoff_mutex
);
174 for (cnt
= 0; cnt
< MAXQUOTAS
; cnt
++) {
175 if (type
!= -1 && cnt
!= type
)
177 if (!sb_has_quota_enabled(sb
, cnt
))
179 mutex_lock_nested(&sb_dqopt(sb
)->files
[cnt
]->i_mutex
, I_MUTEX_QUOTA
);
180 truncate_inode_pages(&sb_dqopt(sb
)->files
[cnt
]->i_data
, 0);
181 mutex_unlock(&sb_dqopt(sb
)->files
[cnt
]->i_mutex
);
183 mutex_unlock(&sb_dqopt(sb
)->dqonoff_mutex
);
186 void sync_dquots(struct super_block
*sb
, int type
)
191 if (sb
->s_qcop
->quota_sync
)
192 quota_sync_sb(sb
, type
);
198 list_for_each_entry(sb
, &super_blocks
, s_list
) {
199 /* This test just improves performance so it needn't be reliable... */
200 for (cnt
= 0, dirty
= 0; cnt
< MAXQUOTAS
; cnt
++)
201 if ((type
== cnt
|| type
== -1) && sb_has_quota_enabled(sb
, cnt
)
202 && info_any_dirty(&sb_dqopt(sb
)->info
[cnt
]))
207 spin_unlock(&sb_lock
);
208 down_read(&sb
->s_umount
);
209 if (sb
->s_root
&& sb
->s_qcop
->quota_sync
)
210 quota_sync_sb(sb
, type
);
211 up_read(&sb
->s_umount
);
213 if (__put_super_and_need_restart(sb
))
216 spin_unlock(&sb_lock
);
219 /* Copy parameters and call proper function */
220 static int do_quotactl(struct super_block
*sb
, int type
, int cmd
, qid_t id
, void __user
*addr
)
228 if (IS_ERR(pathname
= getname(addr
)))
229 return PTR_ERR(pathname
);
230 ret
= sb
->s_qcop
->quota_on(sb
, type
, id
, pathname
);
235 return sb
->s_qcop
->quota_off(sb
, type
);
240 down_read(&sb_dqopt(sb
)->dqptr_sem
);
241 if (!sb_has_quota_enabled(sb
, type
)) {
242 up_read(&sb_dqopt(sb
)->dqptr_sem
);
245 fmt
= sb_dqopt(sb
)->info
[type
].dqi_format
->qf_fmt_id
;
246 up_read(&sb_dqopt(sb
)->dqptr_sem
);
247 if (copy_to_user(addr
, &fmt
, sizeof(fmt
)))
252 struct if_dqinfo info
;
254 if ((ret
= sb
->s_qcop
->get_info(sb
, type
, &info
)))
256 if (copy_to_user(addr
, &info
, sizeof(info
)))
261 struct if_dqinfo info
;
263 if (copy_from_user(&info
, addr
, sizeof(info
)))
265 return sb
->s_qcop
->set_info(sb
, type
, &info
);
270 if ((ret
= sb
->s_qcop
->get_dqblk(sb
, type
, id
, &idq
)))
272 if (copy_to_user(addr
, &idq
, sizeof(idq
)))
279 if (copy_from_user(&idq
, addr
, sizeof(idq
)))
281 return sb
->s_qcop
->set_dqblk(sb
, type
, id
, &idq
);
284 sync_dquots(sb
, type
);
292 if (copy_from_user(&flags
, addr
, sizeof(flags
)))
294 return sb
->s_qcop
->set_xstate(sb
, flags
, cmd
);
297 struct fs_quota_stat fqs
;
299 if ((ret
= sb
->s_qcop
->get_xstate(sb
, &fqs
)))
301 if (copy_to_user(addr
, &fqs
, sizeof(fqs
)))
306 struct fs_disk_quota fdq
;
308 if (copy_from_user(&fdq
, addr
, sizeof(fdq
)))
310 return sb
->s_qcop
->set_xquota(sb
, type
, id
, &fdq
);
313 struct fs_disk_quota fdq
;
315 if ((ret
= sb
->s_qcop
->get_xquota(sb
, type
, id
, &fdq
)))
317 if (copy_to_user(addr
, &fdq
, sizeof(fdq
)))
322 return sb
->s_qcop
->quota_sync(sb
, type
);
323 /* We never reach here unless validity check is broken */
331 * look up a superblock on which quota ops will be performed
332 * - use the name of a block device to find the superblock thereon
334 static inline struct super_block
*quotactl_block(const char __user
*special
)
337 struct block_device
*bdev
;
338 struct super_block
*sb
;
339 char *tmp
= getname(special
);
342 return ERR_PTR(PTR_ERR(tmp
));
343 bdev
= lookup_bdev(tmp
);
346 return ERR_PTR(PTR_ERR(bdev
));
347 sb
= get_super(bdev
);
350 return ERR_PTR(-ENODEV
);
354 return ERR_PTR(-ENODEV
);
359 * This is the system call interface. This communicates with
360 * the user-level programs. Currently this only supports diskquota
361 * calls. Maybe we need to add the process quotas etc. in the future,
362 * but we probably should use rlimits for that.
364 asmlinkage
long sys_quotactl(unsigned int cmd
, const char __user
*special
, qid_t id
, void __user
*addr
)
367 struct super_block
*sb
= NULL
;
370 cmds
= cmd
>> SUBCMDSHIFT
;
371 type
= cmd
& SUBCMDMASK
;
373 if (cmds
!= Q_SYNC
|| special
) {
374 sb
= quotactl_block(special
);
379 ret
= check_quotactl_valid(sb
, type
, cmds
, id
);
381 ret
= do_quotactl(sb
, type
, cmds
, id
, addr
);