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         struct quota_info *dqopt = sb_dqopt(dquot->dq_sb);
  60
  61         if (!dqopt->files[type])
  62                 return -EINVAL;
  63
  64         /* Set structure to 0s in case read fails/is after end of file */
  65         memset(&dqblk, 0, sizeof(struct v1_disk_dqblk));
  66         dquot->dq_sb->s_op->quota_read(dquot->dq_sb, type, (char *)&dqblk,
  67                         sizeof(struct v1_disk_dqblk),
  68                         v1_dqoff(from_kqid(&init_user_ns, dquot->dq_id)));
  69
  70         v1_disk2mem_dqblk(&dquot->dq_dqb, &dqblk);
  71         if (dquot->dq_dqb.dqb_bhardlimit == 0 &&
  72             dquot->dq_dqb.dqb_bsoftlimit == 0 &&
  73             dquot->dq_dqb.dqb_ihardlimit == 0 &&
  74             dquot->dq_dqb.dqb_isoftlimit == 0)
  75                 set_bit(DQ_FAKE_B, &dquot->dq_flags);
  76         dqstats_inc(DQST_READS);
  77
  78         return 0;
  79 }
  80
  81 static int v1_commit_dqblk(struct dquot *dquot)
  82 {
  83         short type = dquot->dq_id.type;
  84         ssize_t ret;
  85         struct v1_disk_dqblk dqblk;
  86
  87         v1_mem2disk_dqblk(&dqblk, &dquot->dq_dqb);
  88         if (((type == USRQUOTA) && uid_eq(dquot->dq_id.uid, GLOBAL_ROOT_UID)) ||
  89             ((type == GRPQUOTA) && gid_eq(dquot->dq_id.gid, GLOBAL_ROOT_GID))) {
  90                 dqblk.dqb_btime =
  91                         sb_dqopt(dquot->dq_sb)->info[type].dqi_bgrace;
  92                 dqblk.dqb_itime =
  93                         sb_dqopt(dquot->dq_sb)->info[type].dqi_igrace;
  94         }
  95         ret = 0;
  96         if (sb_dqopt(dquot->dq_sb)->files[type])
  97                 ret = dquot->dq_sb->s_op->quota_write(dquot->dq_sb, type,
  98                         (char *)&dqblk, sizeof(struct v1_disk_dqblk),
  99                         v1_dqoff(from_kqid(&init_user_ns, dquot->dq_id)));
 100         if (ret != sizeof(struct v1_disk_dqblk)) {
 101                 quota_error(dquot->dq_sb, "dquota write failed");
 102                 if (ret >= 0)
 103                         ret = -EIO;
 104                 goto out;
 105         }
 106         ret = 0;
 107
 108 out:
 109         dqstats_inc(DQST_WRITES);
 110
 111         return ret;
 112 }
 113
 114 /* Magics of new quota format */
 115 #define V2_INITQMAGICS {\
 116         0xd9c01f11,     /* USRQUOTA */\
 117         0xd9c01927      /* GRPQUOTA */\
 118 }
 119
 120 /* Header of new quota format */
 121 struct v2_disk_dqheader {
 122         __le32 dqh_magic;        /* Magic number identifying file */
 123         __le32 dqh_version;      /* File version */
 124 };
 125
 126 static int v1_check_quota_file(struct super_block *sb, int type)
 127 {
 128         struct inode *inode = sb_dqopt(sb)->files[type];
 129         ulong blocks;
 130         size_t off;
 131         struct v2_disk_dqheader dqhead;
 132         ssize_t size;
 133         loff_t isize;
 134         static const uint quota_magics[] = V2_INITQMAGICS;
 135
 136         isize = i_size_read(inode);
 137         if (!isize)
 138                 return 0;
 139         blocks = isize >> BLOCK_SIZE_BITS;
 140         off = isize & (BLOCK_SIZE - 1);
 141         if ((blocks % sizeof(struct v1_disk_dqblk) * BLOCK_SIZE + off) %
 142             sizeof(struct v1_disk_dqblk))
 143                 return 0;
 144         /* Doublecheck whether we didn't get file with new format - with old
 145          * quotactl() this could happen */
 146         size = sb->s_op->quota_read(sb, type, (char *)&dqhead,
 147                                     sizeof(struct v2_disk_dqheader), 0);
 148         if (size != sizeof(struct v2_disk_dqheader))
 149                 return 1;       /* Probably not new format */
 150         if (le32_to_cpu(dqhead.dqh_magic) != quota_magics[type])
 151                 return 1;       /* Definitely not new format */
 152         printk(KERN_INFO
 153                "VFS: %s: Refusing to turn on old quota format on given file."
 154                " It probably contains newer quota format.\n", sb->s_id);
 155         return 0;               /* Seems like a new format file -> refuse it */
 156 }
 157
 158 static int v1_read_file_info(struct super_block *sb, int type)
 159 {
 160         struct quota_info *dqopt = sb_dqopt(sb);
 161         struct v1_disk_dqblk dqblk;
 162         int ret;
 163
 164         down_read(&dqopt->dqio_sem);
 165         ret = sb->s_op->quota_read(sb, type, (char *)&dqblk,
 166                                 sizeof(struct v1_disk_dqblk), v1_dqoff(0));
 167         if (ret != sizeof(struct v1_disk_dqblk)) {
 168                 if (ret >= 0)
 169                         ret = -EIO;
 170                 goto out;
 171         }
 172         ret = 0;
 173         /* limits are stored as unsigned 32-bit data */
 174         dqopt->info[type].dqi_max_spc_limit = 0xffffffffULL << QUOTABLOCK_BITS;
 175         dqopt->info[type].dqi_max_ino_limit = 0xffffffff;
 176         dqopt->info[type].dqi_igrace =
 177                         dqblk.dqb_itime ? dqblk.dqb_itime : MAX_IQ_TIME;
 178         dqopt->info[type].dqi_bgrace =
 179                         dqblk.dqb_btime ? dqblk.dqb_btime : MAX_DQ_TIME;
 180 out:
 181         up_read(&dqopt->dqio_sem);
 182         return ret;
 183 }
 184
 185 static int v1_write_file_info(struct super_block *sb, int type)
 186 {
 187         struct quota_info *dqopt = sb_dqopt(sb);
 188         struct v1_disk_dqblk dqblk;
 189         int ret;
 190
 191         down_write(&dqopt->dqio_sem);
 192         ret = sb->s_op->quota_read(sb, type, (char *)&dqblk,
 193                                 sizeof(struct v1_disk_dqblk), v1_dqoff(0));
 194         if (ret != sizeof(struct v1_disk_dqblk)) {
 195                 if (ret >= 0)
 196                         ret = -EIO;
 197                 goto out;
 198         }
 199         spin_lock(&dq_data_lock);
 200         dqopt->info[type].dqi_flags &= ~DQF_INFO_DIRTY;
 201         dqblk.dqb_itime = dqopt->info[type].dqi_igrace;
 202         dqblk.dqb_btime = dqopt->info[type].dqi_bgrace;
 203         spin_unlock(&dq_data_lock);
 204         ret = sb->s_op->quota_write(sb, type, (char *)&dqblk,
 205               sizeof(struct v1_disk_dqblk), v1_dqoff(0));
 206         if (ret == sizeof(struct v1_disk_dqblk))
 207                 ret = 0;
 208         else if (ret > 0)
 209                 ret = -EIO;
 210 out:
 211         up_write(&dqopt->dqio_sem);
 212         return ret;
 213 }
 214
 215 static const struct quota_format_ops v1_format_ops = {
 216         .check_quota_file       = v1_check_quota_file,
 217         .read_file_info         = v1_read_file_info,
 218         .write_file_info        = v1_write_file_info,
 219         .free_file_info         = NULL,
 220         .read_dqblk             = v1_read_dqblk,
 221         .commit_dqblk           = v1_commit_dqblk,
 222 };
 223
 224 static struct quota_format_type v1_quota_format = {
 225         .qf_fmt_id      = QFMT_VFS_OLD,
 226         .qf_ops         = &v1_format_ops,
 227         .qf_owner       = THIS_MODULE
 228 };
 229
 230 static int __init init_v1_quota_format(void)
 231 {
 232         return register_quota_format(&v1_quota_format);
 233 }
 234
 235 static void __exit exit_v1_quota_format(void)
 236 {
 237         unregister_quota_format(&v1_quota_format);
 238 }
 239
 240 module_init(init_v1_quota_format);
 241 module_exit(exit_v1_quota_format);
 242