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_id.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),
  67                        v1_dqoff(from_kqid(&init_user_ns, dquot->dq_id)));
  68
  69        v1_disk2mem_dqblk(&dquot->dq_dqb, &dqblk);
  70        if (dquot->dq_dqb.dqb_bhardlimit == 0 &&
  71            dquot->dq_dqb.dqb_bsoftlimit == 0 &&
  72            dquot->dq_dqb.dqb_ihardlimit == 0 &&
  73            dquot->dq_dqb.dqb_isoftlimit == 0)
  74                set_bit(DQ_FAKE_B, &dquot->dq_flags);
  75        dqstats_inc(DQST_READS);
  76
  77        return 0;
  78}
  79
  80static int v1_commit_dqblk(struct dquot *dquot)
  81{
  82        short type = dquot->dq_id.type;
  83        ssize_t ret;
  84        struct v1_disk_dqblk dqblk;
  85
  86        v1_mem2disk_dqblk(&dqblk, &dquot->dq_dqb);
  87        if (((type == USRQUOTA) && uid_eq(dquot->dq_id.uid, GLOBAL_ROOT_UID)) ||
  88            ((type == GRPQUOTA) && gid_eq(dquot->dq_id.gid, GLOBAL_ROOT_GID))) {
  89                dqblk.dqb_btime =
  90                        sb_dqopt(dquot->dq_sb)->info[type].dqi_bgrace;
  91                dqblk.dqb_itime =
  92                        sb_dqopt(dquot->dq_sb)->info[type].dqi_igrace;
  93        }
  94        ret = 0;
  95        if (sb_dqopt(dquot->dq_sb)->files[type])
  96                ret = dquot->dq_sb->s_op->quota_write(dquot->dq_sb, type,
  97                        (char *)&dqblk, sizeof(struct v1_disk_dqblk),
  98                        v1_dqoff(from_kqid(&init_user_ns, dquot->dq_id)));
  99        if (ret != sizeof(struct v1_disk_dqblk)) {
 100                quota_error(dquot->dq_sb, "dquota write failed");
 101                if (ret >= 0)
 102                        ret = -EIO;
 103                goto out;
 104        }
 105        ret = 0;
 106
 107out:
 108        dqstats_inc(DQST_WRITES);
 109
 110        return ret;
 111}
 112
 113/* Magics of new quota format */
 114#define V2_INITQMAGICS {\
 115        0xd9c01f11,     /* USRQUOTA */\
 116        0xd9c01927      /* GRPQUOTA */\
 117}
 118
 119/* Header of new quota format */
 120struct v2_disk_dqheader {
 121        __le32 dqh_magic;        /* Magic number identifying file */
 122        __le32 dqh_version;      /* File version */
 123};
 124
 125static int v1_check_quota_file(struct super_block *sb, int type)
 126{
 127        struct inode *inode = sb_dqopt(sb)->files[type];
 128        ulong blocks;
 129        size_t off; 
 130        struct v2_disk_dqheader dqhead;
 131        ssize_t size;
 132        loff_t isize;
 133        static const uint quota_magics[] = V2_INITQMAGICS;
 134
 135        isize = i_size_read(inode);
 136        if (!isize)
 137                return 0;
 138        blocks = isize >> BLOCK_SIZE_BITS;
 139        off = isize & (BLOCK_SIZE - 1);
 140        if ((blocks % sizeof(struct v1_disk_dqblk) * BLOCK_SIZE + off) %
 141            sizeof(struct v1_disk_dqblk))
 142                return 0;
 143        /* Doublecheck whether we didn't get file with new format - with old
 144         * quotactl() this could happen */
 145        size = sb->s_op->quota_read(sb, type, (char *)&dqhead,
 146                                    sizeof(struct v2_disk_dqheader), 0);
 147        if (size != sizeof(struct v2_disk_dqheader))
 148                return 1;       /* Probably not new format */
 149        if (le32_to_cpu(dqhead.dqh_magic) != quota_magics[type])
 150                return 1;       /* Definitely not new format */
 151        printk(KERN_INFO
 152               "VFS: %s: Refusing to turn on old quota format on given file."
 153               " It probably contains newer quota format.\n", sb->s_id);
 154        return 0;               /* Seems like a new format file -> refuse it */
 155}
 156
 157static int v1_read_file_info(struct super_block *sb, int type)
 158{
 159        struct quota_info *dqopt = sb_dqopt(sb);
 160        struct v1_disk_dqblk dqblk;
 161        int ret;
 162
 163        ret = sb->s_op->quota_read(sb, type, (char *)&dqblk,
 164                                sizeof(struct v1_disk_dqblk), v1_dqoff(0));
 165        if (ret != sizeof(struct v1_disk_dqblk)) {
 166                if (ret >= 0)
 167                        ret = -EIO;
 168                goto out;
 169        }
 170        ret = 0;
 171        /* limits are stored as unsigned 32-bit data */
 172        dqopt->info[type].dqi_maxblimit = 0xffffffff;
 173        dqopt->info[type].dqi_maxilimit = 0xffffffff;
 174        dqopt->info[type].dqi_igrace =
 175                        dqblk.dqb_itime ? dqblk.dqb_itime : MAX_IQ_TIME;
 176        dqopt->info[type].dqi_bgrace =
 177                        dqblk.dqb_btime ? dqblk.dqb_btime : MAX_DQ_TIME;
 178out:
 179        return ret;
 180}
 181
 182static int v1_write_file_info(struct super_block *sb, int type)
 183{
 184        struct quota_info *dqopt = sb_dqopt(sb);
 185        struct v1_disk_dqblk dqblk;
 186        int ret;
 187
 188        dqopt->info[type].dqi_flags &= ~DQF_INFO_DIRTY;
 189        ret = sb->s_op->quota_read(sb, type, (char *)&dqblk,
 190                                sizeof(struct v1_disk_dqblk), v1_dqoff(0));
 191        if (ret != sizeof(struct v1_disk_dqblk)) {
 192                if (ret >= 0)
 193                        ret = -EIO;
 194                goto out;
 195        }
 196        dqblk.dqb_itime = dqopt->info[type].dqi_igrace;
 197        dqblk.dqb_btime = dqopt->info[type].dqi_bgrace;
 198        ret = sb->s_op->quota_write(sb, type, (char *)&dqblk,
 199              sizeof(struct v1_disk_dqblk), v1_dqoff(0));
 200        if (ret == sizeof(struct v1_disk_dqblk))
 201                ret = 0;
 202        else if (ret > 0)
 203                ret = -EIO;
 204out:
 205        return ret;
 206}
 207
 208static const struct quota_format_ops v1_format_ops = {
 209        .check_quota_file       = v1_check_quota_file,
 210        .read_file_info         = v1_read_file_info,
 211        .write_file_info        = v1_write_file_info,
 212        .free_file_info         = NULL,
 213        .read_dqblk             = v1_read_dqblk,
 214        .commit_dqblk           = v1_commit_dqblk,
 215};
 216
 217static struct quota_format_type v1_quota_format = {
 218        .qf_fmt_id      = QFMT_VFS_OLD,
 219        .qf_ops         = &v1_format_ops,
 220        .qf_owner       = THIS_MODULE
 221};
 222
 223static int __init init_v1_quota_format(void)
 224{
 225        return register_quota_format(&v1_quota_format);
 226}
 227
 228static void __exit exit_v1_quota_format(void)
 229{
 230        unregister_quota_format(&v1_quota_format);
 231}
 232
 233module_init(init_v1_quota_format);
 234module_exit(exit_v1_quota_format);
 235
 236
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