fs/quota/quota_v1.c

   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
  14 MODULE_AUTHOR("Jan Kara");
  15 MODULE_DESCRIPTION("Old quota format support");
  16 MODULE_LICENSE("GPL");
  17
  18 #define QUOTABLOCK_BITS 10
  19 #define QUOTABLOCK_SIZE (1 << QUOTABLOCK_BITS)
  20
  21 static inline qsize_t v1_stoqb(qsize_t space)
  22 {
  23         return (space + QUOTABLOCK_SIZE - 1) >> QUOTABLOCK_BITS;
  24 }
  25
  26 static inline qsize_t v1_qbtos(qsize_t blocks)
  27 {
  28         return blocks << QUOTABLOCK_BITS;
  29 }
  30
  31 static 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
  43 static 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
  55 static 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
  80 static 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
 107 out:
 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 */
 120 struct v2_disk_dqheader {
 121         __le32 dqh_magic;        /* Magic number identifying file */
 122         __le32 dqh_version;      /* File version */
 123 };
 124
 125 static 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
 157 static 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;
 178 out:
 179         return ret;
 180 }
 181
 182 static 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;
 204 out:
 205         return ret;
 206 }
 207
 208 static 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
 217 static 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
 223 static int __init init_v1_quota_format(void)
 224 {
 225         return register_quota_format(&v1_quota_format);
 226 }
 227
 228 static void __exit exit_v1_quota_format(void)
 229 {
 230         unregister_quota_format(&v1_quota_format);
 231 }
 232
 233 module_init(init_v1_quota_format);
 234 module_exit(exit_v1_quota_format);
 235