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linux/fs/quota/quota.c
Chandra Seetharaman af30cb446d quota: Add a new quotactl command Q_XGETQSTATV 
XFS now supports three types of quotas (user, group and project).

Current version of Q_XGETSTAT has support for only two types of quotas.
In order to support three types of quotas, the interface, specifically
struct fs_quota_stat, need to be expanded. Current version of fs_quota_stat
does not allow expansion without breaking backward compatibility.

So, a quotactl command and new fs_quota_stat structure need to be added.

This patch adds a new command Q_XGETQSTATV to quotactl() which takes
a new data structure fs_quota_statv. This new data structure provides
support for future expansion and backward compatibility.

Callers of the new quotactl command have to set the version of the data
structure being passed, and kernel will fill as much data as requested.
If the kernel does not support the user-space provided version, EINVAL
will be returned. User-space can reduce the version number and call the same
quotactl again.

Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Rich Johnston <rjohnston@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>

[v2: Applied rjohnston's suggestions as per Chandra's request. -bpm]
2013-08-20 16:53:58 -05:00

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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 <linux/uaccess.h>
#include <linux/kernel.h>
#include <linux/security.h>
#include <linux/syscalls.h>
#include <linux/capability.h>
#include <linux/quotaops.h>
#include <linux/types.h>
#include <linux/writeback.h>
static int check_quotactl_permission(struct super_block *sb, int type, int cmd,
qid_t id)
{
switch (cmd) {
/* these commands do not require any special privilegues */
case Q_GETFMT:
case Q_SYNC:
case Q_GETINFO:
case Q_XGETQSTAT:
case Q_XGETQSTATV:
case Q_XQUOTASYNC:
break;
/* allow to query information for dquots we "own" */
case Q_GETQUOTA:
case Q_XGETQUOTA:
if ((type == USRQUOTA && uid_eq(current_euid(), make_kuid(current_user_ns(), id))) ||
(type == GRPQUOTA && in_egroup_p(make_kgid(current_user_ns(), id))))
break;
/*FALLTHROUGH*/
default:
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
}
return security_quotactl(cmd, type, id, sb);
}
static void quota_sync_one(struct super_block *sb, void *arg)
{
if (sb->s_qcop && sb->s_qcop->quota_sync)
sb->s_qcop->quota_sync(sb, *(int *)arg);
}
static int quota_sync_all(int type)
{
int ret;
if (type >= MAXQUOTAS)
return -EINVAL;
ret = security_quotactl(Q_SYNC, type, 0, NULL);
if (!ret)
iterate_supers(quota_sync_one, &type);
return ret;
}
static int quota_quotaon(struct super_block *sb, int type, int cmd, qid_t id,
struct path *path)
{
if (!sb->s_qcop->quota_on && !sb->s_qcop->quota_on_meta)
return -ENOSYS;
if (sb->s_qcop->quota_on_meta)
return sb->s_qcop->quota_on_meta(sb, type, id);
if (IS_ERR(path))
return PTR_ERR(path);
return sb->s_qcop->quota_on(sb, type, id, path);
}
static int quota_getfmt(struct super_block *sb, int type, void __user *addr)
{
__u32 fmt;
down_read(&sb_dqopt(sb)->dqptr_sem);
if (!sb_has_quota_active(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;
}
static int quota_getinfo(struct super_block *sb, int type, void __user *addr)
{
struct if_dqinfo info;
int ret;
if (!sb->s_qcop->get_info)
return -ENOSYS;
ret = sb->s_qcop->get_info(sb, type, &info);
if (!ret && copy_to_user(addr, &info, sizeof(info)))
return -EFAULT;
return ret;
}
static int quota_setinfo(struct super_block *sb, int type, void __user *addr)
{
struct if_dqinfo info;
if (copy_from_user(&info, addr, sizeof(info)))
return -EFAULT;
if (!sb->s_qcop->set_info)
return -ENOSYS;
return sb->s_qcop->set_info(sb, type, &info);
}
static void copy_to_if_dqblk(struct if_dqblk *dst, struct fs_disk_quota *src)
{
dst->dqb_bhardlimit = src->d_blk_hardlimit;
dst->dqb_bsoftlimit = src->d_blk_softlimit;
dst->dqb_curspace = src->d_bcount;
dst->dqb_ihardlimit = src->d_ino_hardlimit;
dst->dqb_isoftlimit = src->d_ino_softlimit;
dst->dqb_curinodes = src->d_icount;
dst->dqb_btime = src->d_btimer;
dst->dqb_itime = src->d_itimer;
dst->dqb_valid = QIF_ALL;
}
static int quota_getquota(struct super_block *sb, int type, qid_t id,
void __user *addr)
{
struct kqid qid;
struct fs_disk_quota fdq;
struct if_dqblk idq;
int ret;
if (!sb->s_qcop->get_dqblk)
return -ENOSYS;
qid = make_kqid(current_user_ns(), type, id);
if (!qid_valid(qid))
return -EINVAL;
ret = sb->s_qcop->get_dqblk(sb, qid, &fdq);
if (ret)
return ret;
copy_to_if_dqblk(&idq, &fdq);
if (copy_to_user(addr, &idq, sizeof(idq)))
return -EFAULT;
return 0;
}
static void copy_from_if_dqblk(struct fs_disk_quota *dst, struct if_dqblk *src)
{
dst->d_blk_hardlimit = src->dqb_bhardlimit;
dst->d_blk_softlimit = src->dqb_bsoftlimit;
dst->d_bcount = src->dqb_curspace;
dst->d_ino_hardlimit = src->dqb_ihardlimit;
dst->d_ino_softlimit = src->dqb_isoftlimit;
dst->d_icount = src->dqb_curinodes;
dst->d_btimer = src->dqb_btime;
dst->d_itimer = src->dqb_itime;
dst->d_fieldmask = 0;
if (src->dqb_valid & QIF_BLIMITS)
dst->d_fieldmask |= FS_DQ_BSOFT | FS_DQ_BHARD;
if (src->dqb_valid & QIF_SPACE)
dst->d_fieldmask |= FS_DQ_BCOUNT;
if (src->dqb_valid & QIF_ILIMITS)
dst->d_fieldmask |= FS_DQ_ISOFT | FS_DQ_IHARD;
if (src->dqb_valid & QIF_INODES)
dst->d_fieldmask |= FS_DQ_ICOUNT;
if (src->dqb_valid & QIF_BTIME)
dst->d_fieldmask |= FS_DQ_BTIMER;
if (src->dqb_valid & QIF_ITIME)
dst->d_fieldmask |= FS_DQ_ITIMER;
}
static int quota_setquota(struct super_block *sb, int type, qid_t id,
void __user *addr)
{
struct fs_disk_quota fdq;
struct if_dqblk idq;
struct kqid qid;
if (copy_from_user(&idq, addr, sizeof(idq)))
return -EFAULT;
if (!sb->s_qcop->set_dqblk)
return -ENOSYS;
qid = make_kqid(current_user_ns(), type, id);
if (!qid_valid(qid))
return -EINVAL;
copy_from_if_dqblk(&fdq, &idq);
return sb->s_qcop->set_dqblk(sb, qid, &fdq);
}
static int quota_setxstate(struct super_block *sb, int cmd, void __user *addr)
{
__u32 flags;
if (copy_from_user(&flags, addr, sizeof(flags)))
return -EFAULT;
if (!sb->s_qcop->set_xstate)
return -ENOSYS;
return sb->s_qcop->set_xstate(sb, flags, cmd);
}
static int quota_getxstate(struct super_block *sb, void __user *addr)
{
struct fs_quota_stat fqs;
int ret;
if (!sb->s_qcop->get_xstate)
return -ENOSYS;
ret = sb->s_qcop->get_xstate(sb, &fqs);
if (!ret && copy_to_user(addr, &fqs, sizeof(fqs)))
return -EFAULT;
return ret;
}
static int quota_getxstatev(struct super_block *sb, void __user *addr)
{
struct fs_quota_statv fqs;
int ret;
if (!sb->s_qcop->get_xstatev)
return -ENOSYS;
memset(&fqs, 0, sizeof(fqs));
if (copy_from_user(&fqs, addr, 1)) /* Just read qs_version */
return -EFAULT;
/* If this kernel doesn't support user specified version, fail */
switch (fqs.qs_version) {
case FS_QSTATV_VERSION1:
break;
default:
return -EINVAL;
}
ret = sb->s_qcop->get_xstatev(sb, &fqs);
if (!ret && copy_to_user(addr, &fqs, sizeof(fqs)))
return -EFAULT;
return ret;
}
static int quota_setxquota(struct super_block *sb, int type, qid_t id,
void __user *addr)
{
struct fs_disk_quota fdq;
struct kqid qid;
if (copy_from_user(&fdq, addr, sizeof(fdq)))
return -EFAULT;
if (!sb->s_qcop->set_dqblk)
return -ENOSYS;
qid = make_kqid(current_user_ns(), type, id);
if (!qid_valid(qid))
return -EINVAL;
return sb->s_qcop->set_dqblk(sb, qid, &fdq);
}
static int quota_getxquota(struct super_block *sb, int type, qid_t id,
void __user *addr)
{
struct fs_disk_quota fdq;
struct kqid qid;
int ret;
if (!sb->s_qcop->get_dqblk)
return -ENOSYS;
qid = make_kqid(current_user_ns(), type, id);
if (!qid_valid(qid))
return -EINVAL;
ret = sb->s_qcop->get_dqblk(sb, qid, &fdq);
if (!ret && copy_to_user(addr, &fdq, sizeof(fdq)))
return -EFAULT;
return ret;
}
/* Copy parameters and call proper function */
static int do_quotactl(struct super_block *sb, int type, int cmd, qid_t id,
void __user *addr, struct path *path)
{
int ret;
if (type >= (XQM_COMMAND(cmd) ? XQM_MAXQUOTAS : MAXQUOTAS))
return -EINVAL;
if (!sb->s_qcop)
return -ENOSYS;
ret = check_quotactl_permission(sb, type, cmd, id);
if (ret < 0)
return ret;
switch (cmd) {
case Q_QUOTAON:
return quota_quotaon(sb, type, cmd, id, path);
case Q_QUOTAOFF:
if (!sb->s_qcop->quota_off)
return -ENOSYS;
return sb->s_qcop->quota_off(sb, type);
case Q_GETFMT:
return quota_getfmt(sb, type, addr);
case Q_GETINFO:
return quota_getinfo(sb, type, addr);
case Q_SETINFO:
return quota_setinfo(sb, type, addr);
case Q_GETQUOTA:
return quota_getquota(sb, type, id, addr);
case Q_SETQUOTA:
return quota_setquota(sb, type, id, addr);
case Q_SYNC:
if (!sb->s_qcop->quota_sync)
return -ENOSYS;
return sb->s_qcop->quota_sync(sb, type);
case Q_XQUOTAON:
case Q_XQUOTAOFF:
case Q_XQUOTARM:
return quota_setxstate(sb, cmd, addr);
case Q_XGETQSTAT:
return quota_getxstate(sb, addr);
case Q_XGETQSTATV:
return quota_getxstatev(sb, addr);
case Q_XSETQLIM:
return quota_setxquota(sb, type, id, addr);
case Q_XGETQUOTA:
return quota_getxquota(sb, type, id, addr);
case Q_XQUOTASYNC:
if (sb->s_flags & MS_RDONLY)
return -EROFS;
/* XFS quotas are fully coherent now, making this call a noop */
return 0;
default:
return -EINVAL;
}
}
#ifdef CONFIG_BLOCK
/* Return 1 if 'cmd' will block on frozen filesystem */
static int quotactl_cmd_write(int cmd)
{
switch (cmd) {
case Q_GETFMT:
case Q_GETINFO:
case Q_SYNC:
case Q_XGETQSTAT:
case Q_XGETQSTATV:
case Q_XGETQUOTA:
case Q_XQUOTASYNC:
return 0;
}
return 1;
}
#endif /* CONFIG_BLOCK */
/*
* look up a superblock on which quota ops will be performed
* - use the name of a block device to find the superblock thereon
*/
static struct super_block *quotactl_block(const char __user *special, int cmd)
{
#ifdef CONFIG_BLOCK
struct block_device *bdev;
struct super_block *sb;
struct filename *tmp = getname(special);
if (IS_ERR(tmp))
return ERR_CAST(tmp);
bdev = lookup_bdev(tmp->name);
putname(tmp);
if (IS_ERR(bdev))
return ERR_CAST(bdev);
if (quotactl_cmd_write(cmd))
sb = get_super_thawed(bdev);
else
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.
*/
SYSCALL_DEFINE4(quotactl, unsigned int, cmd, const char __user *, special,
qid_t, id, void __user *, addr)
{
uint cmds, type;
struct super_block *sb = NULL;
struct path path, *pathp = NULL;
int ret;
cmds = cmd >> SUBCMDSHIFT;
type = cmd & SUBCMDMASK;
/*
* As a special case Q_SYNC can be called without a specific device.
* It will iterate all superblocks that have quota enabled and call
* the sync action on each of them.
*/
if (!special) {
if (cmds == Q_SYNC)
return quota_sync_all(type);
return -ENODEV;
}
/*
* Path for quotaon has to be resolved before grabbing superblock
* because that gets s_umount sem which is also possibly needed by path
* resolution (think about autofs) and thus deadlocks could arise.
*/
if (cmds == Q_QUOTAON) {
ret = user_path_at(AT_FDCWD, addr, LOOKUP_FOLLOW|LOOKUP_AUTOMOUNT, &path);
if (ret)
pathp = ERR_PTR(ret);
else
pathp = &path;
}
sb = quotactl_block(special, cmds);
if (IS_ERR(sb)) {
ret = PTR_ERR(sb);
goto out;
}
ret = do_quotactl(sb, type, cmds, id, addr, pathp);
drop_super(sb);
out:
if (pathp && !IS_ERR(pathp))
path_put(pathp);
return ret;
}
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