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aha/fs/quota.c
Vasily Tarasov b716395e2b diskquota: 32bit quota tools on 64bit architectures 
OpenVZ Linux kernel team has discovered the problem with 32bit quota tools
working on 64bit architectures.  In 2.6.10 kernel sys32_quotactl() function
was replaced by sys_quotactl() with the comment "sys_quotactl seems to be
32/64bit clean, enable it for 32bit" However this isn't right.  Look at
if_dqblk structure:

struct if_dqblk {
        __u64 dqb_bhardlimit;
        __u64 dqb_bsoftlimit;
        __u64 dqb_curspace;
        __u64 dqb_ihardlimit;
        __u64 dqb_isoftlimit;
        __u64 dqb_curinodes;
        __u64 dqb_btime;
        __u64 dqb_itime;
        __u32 dqb_valid;
};

For 32 bit quota tools sizeof(if_dqblk) == 0x44.
But for 64 bit kernel its size is 0x48, 'cause of alignment!
Thus we got a problem. Attached patch reintroduce sys32_quotactl() function,
that handles this and related situations.

[michal.k.k.piotrowski@gmail.com: build fix]
[akpm@linux-foundation.org: Make it link with CONFIG_QUOTA=n]
Signed-off-by: Vasily Tarasov <vtaras@openvz.org>
Cc: Andi Kleen <ak@suse.de>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Jan Kara <jack@ucw.cz>
Cc: <linux-arch@vger.kernel.org>
Signed-off-by: Michal Piotrowski <michal.k.k.piotrowski@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-16 09:05:48 -07:00

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/*
* Quota code necessary even when VFS quota support is not compiled
* into the kernel. The interesting stuff is over in dquot.c, here
* we have symbols for initial quotactl(2) handling, the sysctl(2)
* variables, etc - things needed even when quota support disabled.
*/
#include <linux/fs.h>
#include <linux/namei.h>
#include <linux/slab.h>
#include <asm/current.h>
#include <asm/uaccess.h>
#include <linux/compat.h>
#include <linux/kernel.h>
#include <linux/security.h>
#include <linux/syscalls.h>
#include <linux/buffer_head.h>
#include <linux/capability.h>
#include <linux/quotaops.h>
#include <linux/types.h>
/* Check validity of generic quotactl commands */
static int generic_quotactl_valid(struct super_block *sb, int type, int cmd, qid_t id)
{
if (type >= MAXQUOTAS)
return -EINVAL;
if (!sb && cmd != Q_SYNC)
return -ENODEV;
/* Is operation supported? */
if (sb && !sb->s_qcop)
return -ENOSYS;
switch (cmd) {
case Q_GETFMT:
break;
case Q_QUOTAON:
if (!sb->s_qcop->quota_on)
return -ENOSYS;
break;
case Q_QUOTAOFF:
if (!sb->s_qcop->quota_off)
return -ENOSYS;
break;
case Q_SETINFO:
if (!sb->s_qcop->set_info)
return -ENOSYS;
break;
case Q_GETINFO:
if (!sb->s_qcop->get_info)
return -ENOSYS;
break;
case Q_SETQUOTA:
if (!sb->s_qcop->set_dqblk)
return -ENOSYS;
break;
case Q_GETQUOTA:
if (!sb->s_qcop->get_dqblk)
return -ENOSYS;
break;
case Q_SYNC:
if (sb && !sb->s_qcop->quota_sync)
return -ENOSYS;
break;
default:
return -EINVAL;
}
/* Is quota turned on for commands which need it? */
switch (cmd) {
case Q_GETFMT:
case Q_GETINFO:
case Q_QUOTAOFF:
case Q_SETINFO:
case Q_SETQUOTA:
case Q_GETQUOTA:
/* This is just informative test so we are satisfied without a lock */
if (!sb_has_quota_enabled(sb, type))
return -ESRCH;
}
/* Check privileges */
if (cmd == Q_GETQUOTA) {
if (((type == USRQUOTA && current->euid != id) ||
(type == GRPQUOTA && !in_egroup_p(id))) &&
!capable(CAP_SYS_ADMIN))
return -EPERM;
}
else if (cmd != Q_GETFMT && cmd != Q_SYNC && cmd != Q_GETINFO)
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
return 0;
}
/* Check validity of XFS Quota Manager commands */
static int xqm_quotactl_valid(struct super_block *sb, int type, int cmd, qid_t id)
{
if (type >= XQM_MAXQUOTAS)
return -EINVAL;
if (!sb)
return -ENODEV;
if (!sb->s_qcop)
return -ENOSYS;
switch (cmd) {
case Q_XQUOTAON:
case Q_XQUOTAOFF:
case Q_XQUOTARM:
if (!sb->s_qcop->set_xstate)
return -ENOSYS;
break;
case Q_XGETQSTAT:
if (!sb->s_qcop->get_xstate)
return -ENOSYS;
break;
case Q_XSETQLIM:
if (!sb->s_qcop->set_xquota)
return -ENOSYS;
break;
case Q_XGETQUOTA:
if (!sb->s_qcop->get_xquota)
return -ENOSYS;
break;
case Q_XQUOTASYNC:
if (!sb->s_qcop->quota_sync)
return -ENOSYS;
break;
default:
return -EINVAL;
}
/* Check privileges */
if (cmd == Q_XGETQUOTA) {
if (((type == XQM_USRQUOTA && current->euid != id) ||
(type == XQM_GRPQUOTA && !in_egroup_p(id))) &&
!capable(CAP_SYS_ADMIN))
return -EPERM;
} else if (cmd != Q_XGETQSTAT && cmd != Q_XQUOTASYNC) {
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
}
return 0;
}
static int check_quotactl_valid(struct super_block *sb, int type, int cmd, qid_t id)
{
int error;
if (XQM_COMMAND(cmd))
error = xqm_quotactl_valid(sb, type, cmd, id);
else
error = generic_quotactl_valid(sb, type, cmd, id);
if (!error)
error = security_quotactl(cmd, type, id, sb);
return error;
}
static void quota_sync_sb(struct super_block *sb, int type)
{
int cnt;
sb->s_qcop->quota_sync(sb, type);
/* This is not very clever (and fast) but currently I don't know about
* any other simple way of getting quota data to disk and we must get
* them there for userspace to be visible... */
if (sb->s_op->sync_fs)
sb->s_op->sync_fs(sb, 1);
sync_blockdev(sb->s_bdev);
/*
* Now when everything is written we can discard the pagecache so
* that userspace sees the changes.
*/
mutex_lock(&sb_dqopt(sb)->dqonoff_mutex);
for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
if (type != -1 && cnt != type)
continue;
if (!sb_has_quota_enabled(sb, cnt))
continue;
mutex_lock_nested(&sb_dqopt(sb)->files[cnt]->i_mutex, I_MUTEX_QUOTA);
truncate_inode_pages(&sb_dqopt(sb)->files[cnt]->i_data, 0);
mutex_unlock(&sb_dqopt(sb)->files[cnt]->i_mutex);
}
mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
}
void sync_dquots(struct super_block *sb, int type)
{
int cnt, dirty;
if (sb) {
if (sb->s_qcop->quota_sync)
quota_sync_sb(sb, type);
return;
}
spin_lock(&sb_lock);
restart:
list_for_each_entry(sb, &super_blocks, s_list) {
/* This test just improves performance so it needn't be reliable... */
for (cnt = 0, dirty = 0; cnt < MAXQUOTAS; cnt++)
if ((type == cnt || type == -1) && sb_has_quota_enabled(sb, cnt)
&& info_any_dirty(&sb_dqopt(sb)->info[cnt]))
dirty = 1;
if (!dirty)
continue;
sb->s_count++;
spin_unlock(&sb_lock);
down_read(&sb->s_umount);
if (sb->s_root && sb->s_qcop->quota_sync)
quota_sync_sb(sb, type);
up_read(&sb->s_umount);
spin_lock(&sb_lock);
if (__put_super_and_need_restart(sb))
goto restart;
}
spin_unlock(&sb_lock);
}
/* Copy parameters and call proper function */
static int do_quotactl(struct super_block *sb, int type, int cmd, qid_t id, void __user *addr)
{
int ret;
switch (cmd) {
case Q_QUOTAON: {
char *pathname;
if (IS_ERR(pathname = getname(addr)))
return PTR_ERR(pathname);
ret = sb->s_qcop->quota_on(sb, type, id, pathname);
putname(pathname);
return ret;
}
case Q_QUOTAOFF:
return sb->s_qcop->quota_off(sb, type);
case Q_GETFMT: {
__u32 fmt;
down_read(&sb_dqopt(sb)->dqptr_sem);
if (!sb_has_quota_enabled(sb, type)) {
up_read(&sb_dqopt(sb)->dqptr_sem);
return -ESRCH;
}
fmt = sb_dqopt(sb)->info[type].dqi_format->qf_fmt_id;
up_read(&sb_dqopt(sb)->dqptr_sem);
if (copy_to_user(addr, &fmt, sizeof(fmt)))
return -EFAULT;
return 0;
}
case Q_GETINFO: {
struct if_dqinfo info;
if ((ret = sb->s_qcop->get_info(sb, type, &info)))
return ret;
if (copy_to_user(addr, &info, sizeof(info)))
return -EFAULT;
return 0;
}
case Q_SETINFO: {
struct if_dqinfo info;
if (copy_from_user(&info, addr, sizeof(info)))
return -EFAULT;
return sb->s_qcop->set_info(sb, type, &info);
}
case Q_GETQUOTA: {
struct if_dqblk idq;
if ((ret = sb->s_qcop->get_dqblk(sb, type, id, &idq)))
return ret;
if (copy_to_user(addr, &idq, sizeof(idq)))
return -EFAULT;
return 0;
}
case Q_SETQUOTA: {
struct if_dqblk idq;
if (copy_from_user(&idq, addr, sizeof(idq)))
return -EFAULT;
return sb->s_qcop->set_dqblk(sb, type, id, &idq);
}
case Q_SYNC:
sync_dquots(sb, type);
return 0;
case Q_XQUOTAON:
case Q_XQUOTAOFF:
case Q_XQUOTARM: {
__u32 flags;
if (copy_from_user(&flags, addr, sizeof(flags)))
return -EFAULT;
return sb->s_qcop->set_xstate(sb, flags, cmd);
}
case Q_XGETQSTAT: {
struct fs_quota_stat fqs;
if ((ret = sb->s_qcop->get_xstate(sb, &fqs)))
return ret;
if (copy_to_user(addr, &fqs, sizeof(fqs)))
return -EFAULT;
return 0;
}
case Q_XSETQLIM: {
struct fs_disk_quota fdq;
if (copy_from_user(&fdq, addr, sizeof(fdq)))
return -EFAULT;
return sb->s_qcop->set_xquota(sb, type, id, &fdq);
}
case Q_XGETQUOTA: {
struct fs_disk_quota fdq;
if ((ret = sb->s_qcop->get_xquota(sb, type, id, &fdq)))
return ret;
if (copy_to_user(addr, &fdq, sizeof(fdq)))
return -EFAULT;
return 0;
}
case Q_XQUOTASYNC:
return sb->s_qcop->quota_sync(sb, type);
/* We never reach here unless validity check is broken */
default:
BUG();
}
return 0;
}
/*
* look up a superblock on which quota ops will be performed
* - use the name of a block device to find the superblock thereon
*/
static inline struct super_block *quotactl_block(const char __user *special)
{
#ifdef CONFIG_BLOCK
struct block_device *bdev;
struct super_block *sb;
char *tmp = getname(special);
if (IS_ERR(tmp))
return ERR_PTR(PTR_ERR(tmp));
bdev = lookup_bdev(tmp);
putname(tmp);
if (IS_ERR(bdev))
return ERR_PTR(PTR_ERR(bdev));
sb = get_super(bdev);
bdput(bdev);
if (!sb)
return ERR_PTR(-ENODEV);
return sb;
#else
return ERR_PTR(-ENODEV);
#endif
}
/*
* This is the system call interface. This communicates with
* the user-level programs. Currently this only supports diskquota
* calls. Maybe we need to add the process quotas etc. in the future,
* but we probably should use rlimits for that.
*/
asmlinkage long sys_quotactl(unsigned int cmd, const char __user *special, qid_t id, void __user *addr)
{
uint cmds, type;
struct super_block *sb = NULL;
int ret;
cmds = cmd >> SUBCMDSHIFT;
type = cmd & SUBCMDMASK;
if (cmds != Q_SYNC || special) {
sb = quotactl_block(special);
if (IS_ERR(sb))
return PTR_ERR(sb);
}
ret = check_quotactl_valid(sb, type, cmds, id);
if (ret >= 0)
ret = do_quotactl(sb, type, cmds, id, addr);
if (sb)
drop_super(sb);
return ret;
}
#if defined(CONFIG_X86_64) || defined(CONFIG_IA64)
/*
* This code works only for 32 bit quota tools over 64 bit OS (x86_64, ia64)
* and is necessary due to alignment problems.
*/
struct compat_if_dqblk {
compat_u64 dqb_bhardlimit;
compat_u64 dqb_bsoftlimit;
compat_u64 dqb_curspace;
compat_u64 dqb_ihardlimit;
compat_u64 dqb_isoftlimit;
compat_u64 dqb_curinodes;
compat_u64 dqb_btime;
compat_u64 dqb_itime;
compat_uint_t dqb_valid;
};
/* XFS structures */
struct compat_fs_qfilestat {
compat_u64 dqb_bhardlimit;
compat_u64 qfs_nblks;
compat_uint_t qfs_nextents;
};
struct compat_fs_quota_stat {
__s8 qs_version;
__u16 qs_flags;
__s8 qs_pad;
struct compat_fs_qfilestat qs_uquota;
struct compat_fs_qfilestat qs_gquota;
compat_uint_t qs_incoredqs;
compat_int_t qs_btimelimit;
compat_int_t qs_itimelimit;
compat_int_t qs_rtbtimelimit;
__u16 qs_bwarnlimit;
__u16 qs_iwarnlimit;
};
asmlinkage long sys32_quotactl(unsigned int cmd, const char __user *special,
qid_t id, void __user *addr)
{
unsigned int cmds;
struct if_dqblk __user *dqblk;
struct compat_if_dqblk __user *compat_dqblk;
struct fs_quota_stat __user *fsqstat;
struct compat_fs_quota_stat __user *compat_fsqstat;
compat_uint_t data;
u16 xdata;
long ret;
cmds = cmd >> SUBCMDSHIFT;
switch (cmds) {
case Q_GETQUOTA:
dqblk = compat_alloc_user_space(sizeof(struct if_dqblk));
compat_dqblk = addr;
ret = sys_quotactl(cmd, special, id, dqblk);
if (ret)
break;
if (copy_in_user(compat_dqblk, dqblk, sizeof(*compat_dqblk)) ||
get_user(data, &dqblk->dqb_valid) ||
put_user(data, &compat_dqblk->dqb_valid))
ret = -EFAULT;
break;
case Q_SETQUOTA:
dqblk = compat_alloc_user_space(sizeof(struct if_dqblk));
compat_dqblk = addr;
ret = -EFAULT;
if (copy_in_user(dqblk, compat_dqblk, sizeof(*compat_dqblk)) ||
get_user(data, &compat_dqblk->dqb_valid) ||
put_user(data, &dqblk->dqb_valid))
break;
ret = sys_quotactl(cmd, special, id, dqblk);
break;
case Q_XGETQSTAT:
fsqstat = compat_alloc_user_space(sizeof(struct fs_quota_stat));
compat_fsqstat = addr;
ret = sys_quotactl(cmd, special, id, fsqstat);
if (ret)
break;
ret = -EFAULT;
/* Copying qs_version, qs_flags, qs_pad */
if (copy_in_user(compat_fsqstat, fsqstat,
offsetof(struct compat_fs_quota_stat, qs_uquota)))
break;
/* Copying qs_uquota */
if (copy_in_user(&compat_fsqstat->qs_uquota,
&fsqstat->qs_uquota,
sizeof(compat_fsqstat->qs_uquota)) ||
get_user(data, &fsqstat->qs_uquota.qfs_nextents) ||
put_user(data, &compat_fsqstat->qs_uquota.qfs_nextents))
break;
/* Copying qs_gquota */
if (copy_in_user(&compat_fsqstat->qs_gquota,
&fsqstat->qs_gquota,
sizeof(compat_fsqstat->qs_gquota)) ||
get_user(data, &fsqstat->qs_gquota.qfs_nextents) ||
put_user(data, &compat_fsqstat->qs_gquota.qfs_nextents))
break;
/* Copying the rest */
if (copy_in_user(&compat_fsqstat->qs_incoredqs,
&fsqstat->qs_incoredqs,
sizeof(struct compat_fs_quota_stat) -
offsetof(struct compat_fs_quota_stat, qs_incoredqs)) ||
get_user(xdata, &fsqstat->qs_iwarnlimit) ||
put_user(xdata, &compat_fsqstat->qs_iwarnlimit))
break;
ret = 0;
break;
default:
ret = sys_quotactl(cmd, special, id, addr);
}
return ret;
}
#endif
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