linux/fs/quota/quota_v1.c
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   1#include <linux/errno.h>
   2#include <linux/fs.h>
   3#include <linux/quota.h>
   4#include <linux/quotaops.h>
   5#include <linux/dqblk_v1.h>
   6#include <linux/kernel.h>
   7#include <linux/init.h>
   8#include <linux/module.h>
   9
  10#include <asm/byteorder.h>
  11
  12#include "quotaio_v1.h"
  13
  14MODULE_AUTHOR("Jan Kara");
  15MODULE_DESCRIPTION("Old quota format support");
  16MODULE_LICENSE("GPL");
  17
  18#define QUOTABLOCK_BITS 10
  19#define QUOTABLOCK_SIZE (1 << QUOTABLOCK_BITS)
  20
  21static inline qsize_t v1_stoqb(qsize_t space)
  22{
  23        return (space + QUOTABLOCK_SIZE - 1) >> QUOTABLOCK_BITS;
  24}
  25
  26static inline qsize_t v1_qbtos(qsize_t blocks)
  27{
  28        return blocks << QUOTABLOCK_BITS;
  29}
  30
  31static void v1_disk2mem_dqblk(struct mem_dqblk *m, struct v1_disk_dqblk *d)
  32{
  33        m->dqb_ihardlimit = d->dqb_ihardlimit;
  34        m->dqb_isoftlimit = d->dqb_isoftlimit;
  35        m->dqb_curinodes = d->dqb_curinodes;
  36        m->dqb_bhardlimit = v1_qbtos(d->dqb_bhardlimit);
  37        m->dqb_bsoftlimit = v1_qbtos(d->dqb_bsoftlimit);
  38        m->dqb_curspace = v1_qbtos(d->dqb_curblocks);
  39        m->dqb_itime = d->dqb_itime;
  40        m->dqb_btime = d->dqb_btime;
  41}
  42
  43static void v1_mem2disk_dqblk(struct v1_disk_dqblk *d, struct mem_dqblk *m)
  44{
  45        d->dqb_ihardlimit = m->dqb_ihardlimit;
  46        d->dqb_isoftlimit = m->dqb_isoftlimit;
  47        d->dqb_curinodes = m->dqb_curinodes;
  48        d->dqb_bhardlimit = v1_stoqb(m->dqb_bhardlimit);
  49        d->dqb_bsoftlimit = v1_stoqb(m->dqb_bsoftlimit);
  50        d->dqb_curblocks = v1_stoqb(m->dqb_curspace);
  51        d->dqb_itime = m->dqb_itime;
  52        d->dqb_btime = m->dqb_btime;
  53}
  54
  55static int v1_read_dqblk(struct dquot *dquot)
  56{
  57        int type = dquot->dq_type;
  58        struct v1_disk_dqblk dqblk;
  59
  60        if (!sb_dqopt(dquot->dq_sb)->files[type])
  61                return -EINVAL;
  62
  63        /* Set structure to 0s in case read fails/is after end of file */
  64        memset(&dqblk, 0, sizeof(struct v1_disk_dqblk));
  65        dquot->dq_sb->s_op->quota_read(dquot->dq_sb, type, (char *)&dqblk,
  66                        sizeof(struct v1_disk_dqblk), v1_dqoff(dquot->dq_id));
  67
  68        v1_disk2mem_dqblk(&dquot->dq_dqb, &dqblk);
  69        if (dquot->dq_dqb.dqb_bhardlimit == 0 &&
  70            dquot->dq_dqb.dqb_bsoftlimit == 0 &&
  71            dquot->dq_dqb.dqb_ihardlimit == 0 &&
  72            dquot->dq_dqb.dqb_isoftlimit == 0)
  73                set_bit(DQ_FAKE_B, &dquot->dq_flags);
  74        dqstats_inc(DQST_READS);
  75
  76        return 0;
  77}
  78
  79static int v1_commit_dqblk(struct dquot *dquot)
  80{
  81        short type = dquot->dq_type;
  82        ssize_t ret;
  83        struct v1_disk_dqblk dqblk;
  84
  85        v1_mem2disk_dqblk(&dqblk, &dquot->dq_dqb);
  86        if (dquot->dq_id == 0) {
  87                dqblk.dqb_btime =
  88                        sb_dqopt(dquot->dq_sb)->info[type].dqi_bgrace;
  89                dqblk.dqb_itime =
  90                        sb_dqopt(dquot->dq_sb)->info[type].dqi_igrace;
  91        }
  92        ret = 0;
  93        if (sb_dqopt(dquot->dq_sb)->files[type])
  94                ret = dquot->dq_sb->s_op->quota_write(dquot->dq_sb, type,
  95                        (char *)&dqblk, sizeof(struct v1_disk_dqblk),
  96                        v1_dqoff(dquot->dq_id));
  97        if (ret != sizeof(struct v1_disk_dqblk)) {
  98                quota_error(dquot->dq_sb, "dquota write failed");
  99                if (ret >= 0)
 100                        ret = -EIO;
 101                goto out;
 102        }
 103        ret = 0;
 104
 105out:
 106        dqstats_inc(DQST_WRITES);
 107
 108        return ret;
 109}
 110
 111/* Magics of new quota format */
 112#define V2_INITQMAGICS {\
 113        0xd9c01f11,     /* USRQUOTA */\
 114        0xd9c01927      /* GRPQUOTA */\
 115}
 116
 117/* Header of new quota format */
 118struct v2_disk_dqheader {
 119        __le32 dqh_magic;        /* Magic number identifying file */
 120        __le32 dqh_version;      /* File version */
 121};
 122
 123static int v1_check_quota_file(struct super_block *sb, int type)
 124{
 125        struct inode *inode = sb_dqopt(sb)->files[type];
 126        ulong blocks;
 127        size_t off; 
 128        struct v2_disk_dqheader dqhead;
 129        ssize_t size;
 130        loff_t isize;
 131        static const uint quota_magics[] = V2_INITQMAGICS;
 132
 133        isize = i_size_read(inode);
 134        if (!isize)
 135                return 0;
 136        blocks = isize >> BLOCK_SIZE_BITS;
 137        off = isize & (BLOCK_SIZE - 1);
 138        if ((blocks % sizeof(struct v1_disk_dqblk) * BLOCK_SIZE + off) %
 139            sizeof(struct v1_disk_dqblk))
 140                return 0;
 141        /* Doublecheck whether we didn't get file with new format - with old
 142         * quotactl() this could happen */
 143        size = sb->s_op->quota_read(sb, type, (char *)&dqhead,
 144                                    sizeof(struct v2_disk_dqheader), 0);
 145        if (size != sizeof(struct v2_disk_dqheader))
 146                return 1;       /* Probably not new format */
 147        if (le32_to_cpu(dqhead.dqh_magic) != quota_magics[type])
 148                return 1;       /* Definitely not new format */
 149        printk(KERN_INFO
 150               "VFS: %s: Refusing to turn on old quota format on given file."
 151               " It probably contains newer quota format.\n", sb->s_id);
 152        return 0;               /* Seems like a new format file -> refuse it */
 153}
 154
 155static int v1_read_file_info(struct super_block *sb, int type)
 156{
 157        struct quota_info *dqopt = sb_dqopt(sb);
 158        struct v1_disk_dqblk dqblk;
 159        int ret;
 160
 161        ret = sb->s_op->quota_read(sb, type, (char *)&dqblk,
 162                                sizeof(struct v1_disk_dqblk), v1_dqoff(0));
 163        if (ret != sizeof(struct v1_disk_dqblk)) {
 164                if (ret >= 0)
 165                        ret = -EIO;
 166                goto out;
 167        }
 168        ret = 0;
 169        /* limits are stored as unsigned 32-bit data */
 170        dqopt->info[type].dqi_maxblimit = 0xffffffff;
 171        dqopt->info[type].dqi_maxilimit = 0xffffffff;
 172        dqopt->info[type].dqi_igrace =
 173                        dqblk.dqb_itime ? dqblk.dqb_itime : MAX_IQ_TIME;
 174        dqopt->info[type].dqi_bgrace =
 175                        dqblk.dqb_btime ? dqblk.dqb_btime : MAX_DQ_TIME;
 176out:
 177        return ret;
 178}
 179
 180static int v1_write_file_info(struct super_block *sb, int type)
 181{
 182        struct quota_info *dqopt = sb_dqopt(sb);
 183        struct v1_disk_dqblk dqblk;
 184        int ret;
 185
 186        dqopt->info[type].dqi_flags &= ~DQF_INFO_DIRTY;
 187        ret = sb->s_op->quota_read(sb, type, (char *)&dqblk,
 188                                sizeof(struct v1_disk_dqblk), v1_dqoff(0));
 189        if (ret != sizeof(struct v1_disk_dqblk)) {
 190                if (ret >= 0)
 191                        ret = -EIO;
 192                goto out;
 193        }
 194        dqblk.dqb_itime = dqopt->info[type].dqi_igrace;
 195        dqblk.dqb_btime = dqopt->info[type].dqi_bgrace;
 196        ret = sb->s_op->quota_write(sb, type, (char *)&dqblk,
 197              sizeof(struct v1_disk_dqblk), v1_dqoff(0));
 198        if (ret == sizeof(struct v1_disk_dqblk))
 199                ret = 0;
 200        else if (ret > 0)
 201                ret = -EIO;
 202out:
 203        return ret;
 204}
 205
 206static const struct quota_format_ops v1_format_ops = {
 207        .check_quota_file       = v1_check_quota_file,
 208        .read_file_info         = v1_read_file_info,
 209        .write_file_info        = v1_write_file_info,
 210        .free_file_info         = NULL,
 211        .read_dqblk             = v1_read_dqblk,
 212        .commit_dqblk           = v1_commit_dqblk,
 213};
 214
 215static struct quota_format_type v1_quota_format = {
 216        .qf_fmt_id      = QFMT_VFS_OLD,
 217        .qf_ops         = &v1_format_ops,
 218        .qf_owner       = THIS_MODULE
 219};
 220
 221static int __init init_v1_quota_format(void)
 222{
 223        return register_quota_format(&v1_quota_format);
 224}
 225
 226static void __exit exit_v1_quota_format(void)
 227{
 228        unregister_quota_format(&v1_quota_format);
 229}
 230
 231module_init(init_v1_quota_format);
 232module_exit(exit_v1_quota_format);
 233
 234
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