fs/quota/quota_v1.c

0001 // SPDX-License-Identifier: GPL-2.0-only
0002 #include <linux/errno.h>
0003 #include <linux/fs.h>
0004 #include <linux/quota.h>
0005 #include <linux/quotaops.h>
0006 #include <linux/dqblk_v1.h>
0007 #include <linux/kernel.h>
0008 #include <linux/init.h>
0009 #include <linux/module.h>
0010
0011 #include <asm/byteorder.h>
0012
0013 #include "quotaio_v1.h"
0014
0015 MODULE_AUTHOR("Jan Kara");
0016 MODULE_DESCRIPTION("Old quota format support");
0017 MODULE_LICENSE("GPL");
0018
0019 #define QUOTABLOCK_BITS 10
0020 #define QUOTABLOCK_SIZE (1 << QUOTABLOCK_BITS)
0021
0022 static inline qsize_t v1_stoqb(qsize_t space)
0023 {
0024     return (space + QUOTABLOCK_SIZE - 1) >> QUOTABLOCK_BITS;
0025 }
0026
0027 static inline qsize_t v1_qbtos(qsize_t blocks)
0028 {
0029     return blocks << QUOTABLOCK_BITS;
0030 }
0031
0032 static void v1_disk2mem_dqblk(struct mem_dqblk *m, struct v1_disk_dqblk *d)
0033 {
0034     m->dqb_ihardlimit = d->dqb_ihardlimit;
0035     m->dqb_isoftlimit = d->dqb_isoftlimit;
0036     m->dqb_curinodes = d->dqb_curinodes;
0037     m->dqb_bhardlimit = v1_qbtos(d->dqb_bhardlimit);
0038     m->dqb_bsoftlimit = v1_qbtos(d->dqb_bsoftlimit);
0039     m->dqb_curspace = v1_qbtos(d->dqb_curblocks);
0040     m->dqb_itime = d->dqb_itime;
0041     m->dqb_btime = d->dqb_btime;
0042 }
0043
0044 static void v1_mem2disk_dqblk(struct v1_disk_dqblk *d, struct mem_dqblk *m)
0045 {
0046     d->dqb_ihardlimit = m->dqb_ihardlimit;
0047     d->dqb_isoftlimit = m->dqb_isoftlimit;
0048     d->dqb_curinodes = m->dqb_curinodes;
0049     d->dqb_bhardlimit = v1_stoqb(m->dqb_bhardlimit);
0050     d->dqb_bsoftlimit = v1_stoqb(m->dqb_bsoftlimit);
0051     d->dqb_curblocks = v1_stoqb(m->dqb_curspace);
0052     d->dqb_itime = m->dqb_itime;
0053     d->dqb_btime = m->dqb_btime;
0054 }
0055
0056 static int v1_read_dqblk(struct dquot *dquot)
0057 {
0058     int type = dquot->dq_id.type;
0059     struct v1_disk_dqblk dqblk;
0060     struct quota_info *dqopt = sb_dqopt(dquot->dq_sb);
0061
0062     if (!dqopt->files[type])
0063         return -EINVAL;
0064
0065     /* Set structure to 0s in case read fails/is after end of file */
0066     memset(&dqblk, 0, sizeof(struct v1_disk_dqblk));
0067     dquot->dq_sb->s_op->quota_read(dquot->dq_sb, type, (char *)&dqblk,
0068             sizeof(struct v1_disk_dqblk),
0069             v1_dqoff(from_kqid(&init_user_ns, dquot->dq_id)));
0070
0071     v1_disk2mem_dqblk(&dquot->dq_dqb, &dqblk);
0072     if (dquot->dq_dqb.dqb_bhardlimit == 0 &&
0073         dquot->dq_dqb.dqb_bsoftlimit == 0 &&
0074         dquot->dq_dqb.dqb_ihardlimit == 0 &&
0075         dquot->dq_dqb.dqb_isoftlimit == 0)
0076         set_bit(DQ_FAKE_B, &dquot->dq_flags);
0077     dqstats_inc(DQST_READS);
0078
0079     return 0;
0080 }
0081
0082 static int v1_commit_dqblk(struct dquot *dquot)
0083 {
0084     short type = dquot->dq_id.type;
0085     ssize_t ret;
0086     struct v1_disk_dqblk dqblk;
0087
0088     v1_mem2disk_dqblk(&dqblk, &dquot->dq_dqb);
0089     if (((type == USRQUOTA) && uid_eq(dquot->dq_id.uid, GLOBAL_ROOT_UID)) ||
0090         ((type == GRPQUOTA) && gid_eq(dquot->dq_id.gid, GLOBAL_ROOT_GID))) {
0091         dqblk.dqb_btime =
0092             sb_dqopt(dquot->dq_sb)->info[type].dqi_bgrace;
0093         dqblk.dqb_itime =
0094             sb_dqopt(dquot->dq_sb)->info[type].dqi_igrace;
0095     }
0096     ret = 0;
0097     if (sb_dqopt(dquot->dq_sb)->files[type])
0098         ret = dquot->dq_sb->s_op->quota_write(dquot->dq_sb, type,
0099             (char *)&dqblk, sizeof(struct v1_disk_dqblk),
0100             v1_dqoff(from_kqid(&init_user_ns, dquot->dq_id)));
0101     if (ret != sizeof(struct v1_disk_dqblk)) {
0102         quota_error(dquot->dq_sb, "dquota write failed");
0103         if (ret >= 0)
0104             ret = -EIO;
0105         goto out;
0106     }
0107     ret = 0;
0108
0109 out:
0110     dqstats_inc(DQST_WRITES);
0111
0112     return ret;
0113 }
0114
0115 /* Magics of new quota format */
0116 #define V2_INITQMAGICS {\
0117     0xd9c01f11,     /* USRQUOTA */\
0118     0xd9c01927      /* GRPQUOTA */\
0119 }
0120
0121 /* Header of new quota format */
0122 struct v2_disk_dqheader {
0123     __le32 dqh_magic;        /* Magic number identifying file */
0124     __le32 dqh_version;      /* File version */
0125 };
0126
0127 static int v1_check_quota_file(struct super_block *sb, int type)
0128 {
0129     struct inode *inode = sb_dqopt(sb)->files[type];
0130     ulong blocks;
0131     size_t off;
0132     struct v2_disk_dqheader dqhead;
0133     ssize_t size;
0134     loff_t isize;
0135     static const uint quota_magics[] = V2_INITQMAGICS;
0136
0137     isize = i_size_read(inode);
0138     if (!isize)
0139         return 0;
0140     blocks = isize >> BLOCK_SIZE_BITS;
0141     off = isize & (BLOCK_SIZE - 1);
0142     if ((blocks % sizeof(struct v1_disk_dqblk) * BLOCK_SIZE + off) %
0143         sizeof(struct v1_disk_dqblk))
0144         return 0;
0145     /* Doublecheck whether we didn't get file with new format - with old
0146      * quotactl() this could happen */
0147     size = sb->s_op->quota_read(sb, type, (char *)&dqhead,
0148                     sizeof(struct v2_disk_dqheader), 0);
0149     if (size != sizeof(struct v2_disk_dqheader))
0150         return 1;   /* Probably not new format */
0151     if (le32_to_cpu(dqhead.dqh_magic) != quota_magics[type])
0152         return 1;   /* Definitely not new format */
0153     printk(KERN_INFO
0154            "VFS: %s: Refusing to turn on old quota format on given file."
0155            " It probably contains newer quota format.\n", sb->s_id);
0156         return 0;       /* Seems like a new format file -> refuse it */
0157 }
0158
0159 static int v1_read_file_info(struct super_block *sb, int type)
0160 {
0161     struct quota_info *dqopt = sb_dqopt(sb);
0162     struct v1_disk_dqblk dqblk;
0163     int ret;
0164
0165     down_read(&dqopt->dqio_sem);
0166     ret = sb->s_op->quota_read(sb, type, (char *)&dqblk,
0167                 sizeof(struct v1_disk_dqblk), v1_dqoff(0));
0168     if (ret != sizeof(struct v1_disk_dqblk)) {
0169         if (ret >= 0)
0170             ret = -EIO;
0171         goto out;
0172     }
0173     ret = 0;
0174     /* limits are stored as unsigned 32-bit data */
0175     dqopt->info[type].dqi_max_spc_limit = 0xffffffffULL << QUOTABLOCK_BITS;
0176     dqopt->info[type].dqi_max_ino_limit = 0xffffffff;
0177     dqopt->info[type].dqi_igrace =
0178             dqblk.dqb_itime ? dqblk.dqb_itime : MAX_IQ_TIME;
0179     dqopt->info[type].dqi_bgrace =
0180             dqblk.dqb_btime ? dqblk.dqb_btime : MAX_DQ_TIME;
0181 out:
0182     up_read(&dqopt->dqio_sem);
0183     return ret;
0184 }
0185
0186 static int v1_write_file_info(struct super_block *sb, int type)
0187 {
0188     struct quota_info *dqopt = sb_dqopt(sb);
0189     struct v1_disk_dqblk dqblk;
0190     int ret;
0191
0192     down_write(&dqopt->dqio_sem);
0193     ret = sb->s_op->quota_read(sb, type, (char *)&dqblk,
0194                 sizeof(struct v1_disk_dqblk), v1_dqoff(0));
0195     if (ret != sizeof(struct v1_disk_dqblk)) {
0196         if (ret >= 0)
0197             ret = -EIO;
0198         goto out;
0199     }
0200     spin_lock(&dq_data_lock);
0201     dqopt->info[type].dqi_flags &= ~DQF_INFO_DIRTY;
0202     dqblk.dqb_itime = dqopt->info[type].dqi_igrace;
0203     dqblk.dqb_btime = dqopt->info[type].dqi_bgrace;
0204     spin_unlock(&dq_data_lock);
0205     ret = sb->s_op->quota_write(sb, type, (char *)&dqblk,
0206           sizeof(struct v1_disk_dqblk), v1_dqoff(0));
0207     if (ret == sizeof(struct v1_disk_dqblk))
0208         ret = 0;
0209     else if (ret > 0)
0210         ret = -EIO;
0211 out:
0212     up_write(&dqopt->dqio_sem);
0213     return ret;
0214 }
0215
0216 static const struct quota_format_ops v1_format_ops = {
0217     .check_quota_file   = v1_check_quota_file,
0218     .read_file_info     = v1_read_file_info,
0219     .write_file_info    = v1_write_file_info,
0220     .read_dqblk     = v1_read_dqblk,
0221     .commit_dqblk       = v1_commit_dqblk,
0222 };
0223
0224 static struct quota_format_type v1_quota_format = {
0225     .qf_fmt_id  = QFMT_VFS_OLD,
0226     .qf_ops     = &v1_format_ops,
0227     .qf_owner   = THIS_MODULE
0228 };
0229
0230 static int __init init_v1_quota_format(void)
0231 {
0232         return register_quota_format(&v1_quota_format);
0233 }
0234
0235 static void __exit exit_v1_quota_format(void)
0236 {
0237         unregister_quota_format(&v1_quota_format);
0238 }
0239
0240 module_init(init_v1_quota_format);
0241 module_exit(exit_v1_quota_format);
0242