// SPDX-License-Identifier: GPL-2.0-only
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/quota.h>
#include <linux/quotaops.h>
#include <linux/dqblk_v1.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/module.h>
#include <asm/byteorder.h>
#include "quotaio_v1.h"
MODULE_AUTHOR("Jan Kara");
MODULE_DESCRIPTION("Old quota format support");
MODULE_LICENSE("GPL");
#define QUOTABLOCK_BITS 10
#define QUOTABLOCK_SIZE (1 << QUOTABLOCK_BITS)
static inline qsize_t v1_stoqb(qsize_t space)
{
return (space + QUOTABLOCK_SIZE - 1) >> QUOTABLOCK_BITS;
}
static inline qsize_t v1_qbtos(qsize_t blocks)
{
return blocks << QUOTABLOCK_BITS;
}
static void v1_disk2mem_dqblk(struct mem_dqblk *m, struct v1_disk_dqblk *d)
{
m->dqb_ihardlimit = d->dqb_ihardlimit;
m->dqb_isoftlimit = d->dqb_isoftlimit;
m->dqb_curinodes = d->dqb_curinodes;
m->dqb_bhardlimit = v1_qbtos(d->dqb_bhardlimit);
m->dqb_bsoftlimit = v1_qbtos(d->dqb_bsoftlimit);
m->dqb_curspace = v1_qbtos(d->dqb_curblocks);
m->dqb_itime = d->dqb_itime;
m->dqb_btime = d->dqb_btime;
}
static void v1_mem2disk_dqblk(struct v1_disk_dqblk *d, struct mem_dqblk *m)
{
d->dqb_ihardlimit = m->dqb_ihardlimit;
d->dqb_isoftlimit = m->dqb_isoftlimit;
d->dqb_curinodes = m->dqb_curinodes;
d->dqb_bhardlimit = v1_stoqb(m->dqb_bhardlimit);
d->dqb_bsoftlimit = v1_stoqb(m->dqb_bsoftlimit);
d->dqb_curblocks = v1_stoqb(m->dqb_curspace);
d->dqb_itime = m->dqb_itime;
d->dqb_btime = m->dqb_btime;
}
static int v1_read_dqblk(struct dquot *dquot)
{
int type = dquot->dq_id.type;
struct v1_disk_dqblk dqblk;
struct quota_info *dqopt = sb_dqopt(dquot->dq_sb);
if (!dqopt->files[type])
return -EINVAL;
/* Set structure to 0s in case read fails/is after end of file */
memset(&dqblk, 0, sizeof(struct v1_disk_dqblk));
dquot->dq_sb->s_op->quota_read(dquot->dq_sb, type, (char *)&dqblk,
sizeof(struct v1_disk_dqblk),
v1_dqoff(from_kqid(&init_user_ns, dquot->dq_id)));
v1_disk2mem_dqblk(&dquot->dq_dqb, &dqblk);
if (dquot->dq_dqb.dqb_bhardlimit == 0 &&
dquot->dq_dqb.dqb_bsoftlimit == 0 &&
dquot->dq_dqb.dqb_ihardlimit == 0 &&
dquot->dq_dqb.dqb_isoftlimit == 0)
set_bit(DQ_FAKE_B, &dquot->dq_flags);
dqstats_inc(DQST_READS);
return 0;
}
static int v1_commit_dqblk(struct dquot *dquot)
{
short type = dquot->dq_id.type;
ssize_t ret;
struct v1_disk_dqblk dqblk;
v1_mem2disk_dqblk(&dqblk, &dquot->dq_dqb);
if (((type == USRQUOTA) && uid_eq(dquot->dq_id.uid, GLOBAL_ROOT_UID)) ||
((type == GRPQUOTA) && gid_eq(dquot->dq_id.gid, GLOBAL_ROOT_GID))) {
dqblk.dqb_btime =
sb_dqopt(dquot->dq_sb)->info[type].dqi_bgrace;
dqblk.dqb_itime =
sb_dqopt(dquot->dq_sb)->info[type].dqi_igrace;
}
ret = 0;
if (sb_dqopt(dquot->dq_sb)->files[type])
ret = dquot->dq_sb->s_op->quota_write(dquot->dq_sb, type,
(char *)&dqblk, sizeof(struct v1_disk_dqblk),
v1_dqoff(from_kqid(&init_user_ns, dquot->dq_id)));
if (ret != sizeof(struct v1_disk_dqblk)) {
quota_error(dquot->dq_sb, "dquota write failed");
if (ret >= 0)
ret = -EIO;
goto out;
}
ret = 0;
out:
dqstats_inc(DQST_WRITES);
return ret;
}
/* Magics of new quota format */
#define V2_INITQMAGICS {\
0xd9c01f11, /* USRQUOTA */\
0xd9c01927 /* GRPQUOTA */\
}
/* Header of new quota format */
struct v2_disk_dqheader {
__le32 dqh_magic; /* Magic number identifying file */
__le32 dqh_version; /* File version */
};
static int v1_check_quota_file(struct super_block *sb, int type)
{
struct inode *inode = sb_dqopt(sb)->files[type];
ulong blocks;
size_t off;
struct v2_disk_dqheader dqhead;
ssize_t size;
loff_t isize;
static const uint quota_magics[] = V2_INITQMAGICS;
isize = i_size_read(inode);
if (!isize)
return 0;
blocks = isize >> BLOCK_SIZE_BITS;
off = isize & (BLOCK_SIZE - 1);
if ((blocks % sizeof(struct v1_disk_dqblk) * BLOCK_SIZE + off) %
sizeof(struct v1_disk_dqblk))
return 0;
/* Doublecheck whether we didn't get file with new format - with old
* quotactl() this could happen */
size = sb->s_op->quota_read(sb, type, (char *)&dqhead,
sizeof(struct v2_disk_dqheader), 0);
if (size != sizeof(struct v2_disk_dqheader))
return 1; /* Probably not new format */
if (le32_to_cpu(dqhead.dqh_magic) != quota_magics[type])
return 1; /* Definitely not new format */
printk(KERN_INFO
"VFS: %s: Refusing to turn on old quota format on given file."
" It probably contains newer quota format.\n", sb->s_id);
return 0; /* Seems like a new format file -> refuse it */
}
static int v1_read_file_info(struct super_block *sb, int type)
{
struct quota_info *dqopt = sb_dqopt(sb);
struct v1_disk_dqblk dqblk;
unsigned int memalloc;
int ret;
down_read(&dqopt->dqio_sem);
memalloc = memalloc_nofs_save();
ret = sb->s_op->quota_read(sb, type, (char *)&dqblk,
sizeof(struct v1_disk_dqblk), v1_dqoff(0));
if (ret != sizeof(struct v1_disk_dqblk)) {
if (ret >= 0)
ret = -EIO;
goto out;
}
ret = 0;
/* limits are stored as unsigned 32-bit data */
dqopt->info[type].dqi_max_spc_limit = 0xffffffffULL << QUOTABLOCK_BITS;
dqopt->info[type].dqi_max_ino_limit = 0xffffffff;
dqopt->info[type].dqi_igrace =
dqblk.dqb_itime ? dqblk.dqb_itime : MAX_IQ_TIME;
dqopt->info[type].dqi_bgrace =
dqblk.dqb_btime ? dqblk.dqb_btime : MAX_DQ_TIME;
out:
memalloc_nofs_restore(memalloc);
up_read(&dqopt->dqio_sem);
return ret;
}
static int v1_write_file_info(struct super_block *sb, int type)
{
struct quota_info *dqopt = sb_dqopt(sb);
struct v1_disk_dqblk dqblk;
unsigned int memalloc;
int ret;
down_write(&dqopt->dqio_sem);
memalloc = memalloc_nofs_save();
ret = sb->s_op->quota_read(sb, type, (char *)&dqblk,
sizeof(struct v1_disk_dqblk), v1_dqoff(0));
if (ret != sizeof(struct v1_disk_dqblk)) {
if (ret >= 0)
ret = -EIO;
goto out;
}
spin_lock(&dq_data_lock);
dqopt->info[type].dqi_flags &= ~DQF_INFO_DIRTY;
dqblk.dqb_itime = dqopt->info[type].dqi_igrace;
dqblk.dqb_btime = dqopt->info[type].dqi_bgrace;
spin_unlock(&dq_data_lock);
ret = sb->s_op->quota_write(sb, type, (char *)&dqblk,
sizeof(struct v1_disk_dqblk), v1_dqoff(0));
if (ret == sizeof(struct v1_disk_dqblk))
ret = 0;
else if (ret >= 0)
ret = -EIO;
out:
memalloc_nofs_restore(memalloc);
up_write(&dqopt->dqio_sem);
return ret;
}
static const struct quota_format_ops v1_format_ops = {
.check_quota_file = v1_check_quota_file,
.read_file_info = v1_read_file_info,
.write_file_info = v1_write_file_info,
.read_dqblk = v1_read_dqblk,
.commit_dqblk = v1_commit_dqblk,
};
static struct quota_format_type v1_quota_format = {
.qf_fmt_id = QFMT_VFS_OLD,
.qf_ops = &v1_format_ops,
.qf_owner = THIS_MODULE
};
static int __init init_v1_quota_format(void)
{
register_quota_format(&v1_quota_format);
return 0;
}
static void __exit exit_v1_quota_format(void)
{
unregister_quota_format(&v1_quota_format);
}
module_init(init_v1_quota_format);
module_exit(exit_v1_quota_format);
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