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