quota_v2.c

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/*
 *  vfsv0 quota IO operations on file
 */

#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/mount.h>
#include <linux/dqblk_v2.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/quotaops.h>

#include <asm/byteorder.h>

#include "quota_tree.h"
#include "quotaio_v2.h"

MODULE_AUTHOR("Jan Kara");
MODULE_DESCRIPTION("Quota format v2 support");
MODULE_LICENSE("GPL");

#define __QUOTA_V2_PARANOIA

static void v2r0_mem2diskdqb(void *dp, struct dquot *dquot);
static void v2r0_disk2memdqb(struct dquot *dquot, void *dp);
static int v2r0_is_id(void *dp, struct dquot *dquot);
static void v2r1_mem2diskdqb(void *dp, struct dquot *dquot);
static void v2r1_disk2memdqb(struct dquot *dquot, void *dp);
static int v2r1_is_id(void *dp, struct dquot *dquot);

static struct qtree_fmt_operations v2r0_qtree_ops = {
    .mem2disk_dqblk = v2r0_mem2diskdqb,
    .disk2mem_dqblk = v2r0_disk2memdqb,
    .is_id = v2r0_is_id,
};

static struct qtree_fmt_operations v2r1_qtree_ops = {
    .mem2disk_dqblk = v2r1_mem2diskdqb,
    .disk2mem_dqblk = v2r1_disk2memdqb,
    .is_id = v2r1_is_id,
};

#define QUOTABLOCK_BITS 10
#define QUOTABLOCK_SIZE (1 << QUOTABLOCK_BITS)

static inline qsize_t v2_stoqb(qsize_t space)
{
    return (space + QUOTABLOCK_SIZE - 1) >> QUOTABLOCK_BITS;
}

static inline qsize_t v2_qbtos(qsize_t blocks)
{
    return blocks << QUOTABLOCK_BITS;
}

static int v2_read_header(struct super_block *sb, int type,
              struct v2_disk_dqheader *dqhead)
{
    ssize_t size;

    size = sb->s_op->quota_read(sb, type, (char *)dqhead,
                    sizeof(struct v2_disk_dqheader), 0);
    if (size != sizeof(struct v2_disk_dqheader)) {
        quota_error(sb, "Failed header read: expected=%zd got=%zd",
                sizeof(struct v2_disk_dqheader), size);
        return 0;
    }
    return 1;
}

/* Check whether given file is really vfsv0 quotafile */
static int v2_check_quota_file(struct super_block *sb, int type)
{
    struct v2_disk_dqheader dqhead;
    static const uint quota_magics[] = V2_INITQMAGICS;
    static const uint quota_versions[] = V2_INITQVERSIONS;
 
    if (!v2_read_header(sb, type, &dqhead))
        return 0;
    if (le32_to_cpu(dqhead.dqh_magic) != quota_magics[type] ||
        le32_to_cpu(dqhead.dqh_version) > quota_versions[type])
        return 0;
    return 1;
}

/* Read information header from quota file */
static int v2_read_file_info(struct super_block *sb, int type)
{
    struct v2_disk_dqinfo dinfo;
    struct v2_disk_dqheader dqhead;
    struct mem_dqinfo *info = sb_dqinfo(sb, type);
    struct qtree_mem_dqinfo *qinfo;
    ssize_t size;
    unsigned int version;

    if (!v2_read_header(sb, type, &dqhead))
        return -1;
    version = le32_to_cpu(dqhead.dqh_version);
    if ((info->dqi_fmt_id == QFMT_VFS_V0 && version != 0) ||
        (info->dqi_fmt_id == QFMT_VFS_V1 && version != 1))
        return -1;

    size = sb->s_op->quota_read(sb, type, (char *)&dinfo,
           sizeof(struct v2_disk_dqinfo), V2_DQINFOOFF);
    if (size != sizeof(struct v2_disk_dqinfo)) {
        quota_error(sb, "Can't read info structure");
        return -1;
    }
    info->dqi_priv = kmalloc(sizeof(struct qtree_mem_dqinfo), GFP_NOFS);
    if (!info->dqi_priv) {
        printk(KERN_WARNING
               "Not enough memory for quota information structure.\n");
        return -ENOMEM;
    }
    qinfo = info->dqi_priv;
    if (version == 0) {
        /* limits are stored as unsigned 32-bit data */
        info->dqi_maxblimit = 0xffffffff;
        info->dqi_maxilimit = 0xffffffff;
    } else {
        /* used space is stored as unsigned 64-bit value */
        info->dqi_maxblimit = 0xffffffffffffffffULL;    /* 2^64-1 */
        info->dqi_maxilimit = 0xffffffffffffffffULL;
    }
    info->dqi_bgrace = le32_to_cpu(dinfo.dqi_bgrace);
    info->dqi_igrace = le32_to_cpu(dinfo.dqi_igrace);
    info->dqi_flags = le32_to_cpu(dinfo.dqi_flags);
    qinfo->dqi_sb = sb;
    qinfo->dqi_type = type;
    qinfo->dqi_blocks = le32_to_cpu(dinfo.dqi_blocks);
    qinfo->dqi_free_blk = le32_to_cpu(dinfo.dqi_free_blk);
    qinfo->dqi_free_entry = le32_to_cpu(dinfo.dqi_free_entry);
    qinfo->dqi_blocksize_bits = V2_DQBLKSIZE_BITS;
    qinfo->dqi_usable_bs = 1 << V2_DQBLKSIZE_BITS;
    qinfo->dqi_qtree_depth = qtree_depth(qinfo);
    if (version == 0) {
        qinfo->dqi_entry_size = sizeof(struct v2r0_disk_dqblk);
        qinfo->dqi_ops = &v2r0_qtree_ops;
    } else {
        qinfo->dqi_entry_size = sizeof(struct v2r1_disk_dqblk);
        qinfo->dqi_ops = &v2r1_qtree_ops;
    }
    return 0;
}

/* Write information header to quota file */
static int v2_write_file_info(struct super_block *sb, int type)
{
    struct v2_disk_dqinfo dinfo;
    struct mem_dqinfo *info = sb_dqinfo(sb, type);
    struct qtree_mem_dqinfo *qinfo = info->dqi_priv;
    ssize_t size;

    spin_lock(&dq_data_lock);
    info->dqi_flags &= ~DQF_INFO_DIRTY;
    dinfo.dqi_bgrace = cpu_to_le32(info->dqi_bgrace);
    dinfo.dqi_igrace = cpu_to_le32(info->dqi_igrace);
    dinfo.dqi_flags = cpu_to_le32(info->dqi_flags & DQF_MASK);
    spin_unlock(&dq_data_lock);
    dinfo.dqi_blocks = cpu_to_le32(qinfo->dqi_blocks);
    dinfo.dqi_free_blk = cpu_to_le32(qinfo->dqi_free_blk);
    dinfo.dqi_free_entry = cpu_to_le32(qinfo->dqi_free_entry);
    size = sb->s_op->quota_write(sb, type, (char *)&dinfo,
           sizeof(struct v2_disk_dqinfo), V2_DQINFOOFF);
    if (size != sizeof(struct v2_disk_dqinfo)) {
        quota_error(sb, "Can't write info structure");
        return -1;
    }
    return 0;
}

static void v2r0_disk2memdqb(struct dquot *dquot, void *dp)
{
    struct v2r0_disk_dqblk *d = dp, empty;
    struct mem_dqblk *m = &dquot->dq_dqb;

    m->dqb_ihardlimit = le32_to_cpu(d->dqb_ihardlimit);
    m->dqb_isoftlimit = le32_to_cpu(d->dqb_isoftlimit);
    m->dqb_curinodes = le32_to_cpu(d->dqb_curinodes);
    m->dqb_itime = le64_to_cpu(d->dqb_itime);
    m->dqb_bhardlimit = v2_qbtos(le32_to_cpu(d->dqb_bhardlimit));
    m->dqb_bsoftlimit = v2_qbtos(le32_to_cpu(d->dqb_bsoftlimit));
    m->dqb_curspace = le64_to_cpu(d->dqb_curspace);
    m->dqb_btime = le64_to_cpu(d->dqb_btime);
    /* We need to escape back all-zero structure */
    memset(&empty, 0, sizeof(struct v2r0_disk_dqblk));
    empty.dqb_itime = cpu_to_le64(1);
    if (!memcmp(&empty, dp, sizeof(struct v2r0_disk_dqblk)))
        m->dqb_itime = 0;
}

static void v2r0_mem2diskdqb(void *dp, struct dquot *dquot)
{
    struct v2r0_disk_dqblk *d = dp;
    struct mem_dqblk *m = &dquot->dq_dqb;
    struct qtree_mem_dqinfo *info =
            sb_dqinfo(dquot->dq_sb, dquot->dq_id.type)->dqi_priv;

    d->dqb_ihardlimit = cpu_to_le32(m->dqb_ihardlimit);
    d->dqb_isoftlimit = cpu_to_le32(m->dqb_isoftlimit);
    d->dqb_curinodes = cpu_to_le32(m->dqb_curinodes);
    d->dqb_itime = cpu_to_le64(m->dqb_itime);
    d->dqb_bhardlimit = cpu_to_le32(v2_stoqb(m->dqb_bhardlimit));
    d->dqb_bsoftlimit = cpu_to_le32(v2_stoqb(m->dqb_bsoftlimit));
    d->dqb_curspace = cpu_to_le64(m->dqb_curspace);
    d->dqb_btime = cpu_to_le64(m->dqb_btime);
    d->dqb_id = cpu_to_le32(from_kqid(&init_user_ns, dquot->dq_id));
    if (qtree_entry_unused(info, dp))
        d->dqb_itime = cpu_to_le64(1);
}

static int v2r0_is_id(void *dp, struct dquot *dquot)
{
    struct v2r0_disk_dqblk *d = dp;
    struct qtree_mem_dqinfo *info =
            sb_dqinfo(dquot->dq_sb, dquot->dq_id.type)->dqi_priv;

    if (qtree_entry_unused(info, dp))
        return 0;
    return qid_eq(make_kqid(&init_user_ns, dquot->dq_id.type,
                le32_to_cpu(d->dqb_id)),
              dquot->dq_id);
}

static void v2r1_disk2memdqb(struct dquot *dquot, void *dp)
{
    struct v2r1_disk_dqblk *d = dp, empty;
    struct mem_dqblk *m = &dquot->dq_dqb;

    m->dqb_ihardlimit = le64_to_cpu(d->dqb_ihardlimit);
    m->dqb_isoftlimit = le64_to_cpu(d->dqb_isoftlimit);
    m->dqb_curinodes = le64_to_cpu(d->dqb_curinodes);
    m->dqb_itime = le64_to_cpu(d->dqb_itime);
    m->dqb_bhardlimit = v2_qbtos(le64_to_cpu(d->dqb_bhardlimit));
    m->dqb_bsoftlimit = v2_qbtos(le64_to_cpu(d->dqb_bsoftlimit));
    m->dqb_curspace = le64_to_cpu(d->dqb_curspace);
    m->dqb_btime = le64_to_cpu(d->dqb_btime);
    /* We need to escape back all-zero structure */
    memset(&empty, 0, sizeof(struct v2r1_disk_dqblk));
    empty.dqb_itime = cpu_to_le64(1);
    if (!memcmp(&empty, dp, sizeof(struct v2r1_disk_dqblk)))
        m->dqb_itime = 0;
}

static void v2r1_mem2diskdqb(void *dp, struct dquot *dquot)
{
    struct v2r1_disk_dqblk *d = dp;
    struct mem_dqblk *m = &dquot->dq_dqb;
    struct qtree_mem_dqinfo *info =
            sb_dqinfo(dquot->dq_sb, dquot->dq_id.type)->dqi_priv;

    d->dqb_ihardlimit = cpu_to_le64(m->dqb_ihardlimit);
    d->dqb_isoftlimit = cpu_to_le64(m->dqb_isoftlimit);
    d->dqb_curinodes = cpu_to_le64(m->dqb_curinodes);
    d->dqb_itime = cpu_to_le64(m->dqb_itime);
    d->dqb_bhardlimit = cpu_to_le64(v2_stoqb(m->dqb_bhardlimit));
    d->dqb_bsoftlimit = cpu_to_le64(v2_stoqb(m->dqb_bsoftlimit));
    d->dqb_curspace = cpu_to_le64(m->dqb_curspace);
    d->dqb_btime = cpu_to_le64(m->dqb_btime);
    d->dqb_id = cpu_to_le32(from_kqid(&init_user_ns, dquot->dq_id));
    if (qtree_entry_unused(info, dp))
        d->dqb_itime = cpu_to_le64(1);
}

static int v2r1_is_id(void *dp, struct dquot *dquot)
{
    struct v2r1_disk_dqblk *d = dp;
    struct qtree_mem_dqinfo *info =
            sb_dqinfo(dquot->dq_sb, dquot->dq_id.type)->dqi_priv;

    if (qtree_entry_unused(info, dp))
        return 0;
    return qid_eq(make_kqid(&init_user_ns, dquot->dq_id.type,
                le32_to_cpu(d->dqb_id)),
              dquot->dq_id);
}

static int v2_read_dquot(struct dquot *dquot)
{
    return qtree_read_dquot(sb_dqinfo(dquot->dq_sb, dquot->dq_id.type)->dqi_priv, dquot);
}

static int v2_write_dquot(struct dquot *dquot)
{
    return qtree_write_dquot(sb_dqinfo(dquot->dq_sb, dquot->dq_id.type)->dqi_priv, dquot);
}

static int v2_release_dquot(struct dquot *dquot)
{
    return qtree_release_dquot(sb_dqinfo(dquot->dq_sb, dquot->dq_id.type)->dqi_priv, dquot);
}

static int v2_free_file_info(struct super_block *sb, int type)
{
    kfree(sb_dqinfo(sb, type)->dqi_priv);
    return 0;
}

static const struct quota_format_ops v2_format_ops = {
    .check_quota_file   = v2_check_quota_file,
    .read_file_info     = v2_read_file_info,
    .write_file_info    = v2_write_file_info,
    .free_file_info     = v2_free_file_info,
    .read_dqblk     = v2_read_dquot,
    .commit_dqblk       = v2_write_dquot,
    .release_dqblk      = v2_release_dquot,
};

static struct quota_format_type v2r0_quota_format = {
    .qf_fmt_id  = QFMT_VFS_V0,
    .qf_ops     = &v2_format_ops,
    .qf_owner   = THIS_MODULE
};

static struct quota_format_type v2r1_quota_format = {
    .qf_fmt_id  = QFMT_VFS_V1,
    .qf_ops     = &v2_format_ops,
    .qf_owner   = THIS_MODULE
};

static int __init init_v2_quota_format(void)
{
    int ret;

    ret = register_quota_format(&v2r0_quota_format);
    if (ret)
        return ret;
    return register_quota_format(&v2r1_quota_format);
}

static void __exit exit_v2_quota_format(void)
{
    unregister_quota_format(&v2r0_quota_format);
    unregister_quota_format(&v2r1_quota_format);
}

module_init(init_v2_quota_format);
module_exit(exit_v2_quota_format);