Quelle  quota_v2.c   Sprache: C

// SPDX-License-Identifier: GPL-2.0-only
/*
 * 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");

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

static const 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);
  if (size < 0)
   return size;
  return -EIO;
 }
 return 0;
}

/* 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 quota_info *dqopt = sb_dqopt(sb);
 struct mem_dqinfo *info = &dqopt->info[type];
 struct qtree_mem_dqinfo *qinfo;
 ssize_t size;
 unsigned int version;
 unsigned int memalloc;
 int ret;

 down_read(&dqopt->dqio_sem);
 memalloc = memalloc_nofs_save();
 ret = v2_read_header(sb, type, &dqhead);
 if (ret < 0)
  goto out;
 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)) {
  ret = -EINVAL;
  goto out;
 }

 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");
  if (size < 0)
   ret = size;
  else
   ret = -EIO;
  goto out;
 }
 info->dqi_priv = kmalloc(sizeof(struct qtree_mem_dqinfo), GFP_KERNEL);
 if (!info->dqi_priv) {
  ret = -ENOMEM;
  goto out;
 }
 qinfo = info->dqi_priv;
 if (version == 0) {
  /* limits are stored as unsigned 32-bit data */
  info->dqi_max_spc_limit = 0xffffffffLL << QUOTABLOCK_BITS;
  info->dqi_max_ino_limit = 0xffffffff;
 } else {
  /*
 * Used space is stored as unsigned 64-bit value in bytes but
 * quota core supports only signed 64-bit values so use that
 * as a limit
 */
  info->dqi_max_spc_limit = 0x7fffffffffffffffLL; /* 2^63-1 */
  info->dqi_max_ino_limit = 0x7fffffffffffffffLL;
 }
 info->dqi_bgrace = le32_to_cpu(dinfo.dqi_bgrace);
 info->dqi_igrace = le32_to_cpu(dinfo.dqi_igrace);
 /* No flags currently supported */
 info->dqi_flags = 0;
 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;
 }
 ret = -EUCLEAN;
 /* Some sanity checks of the read headers... */
 if ((loff_t)qinfo->dqi_blocks << qinfo->dqi_blocksize_bits >
     i_size_read(sb_dqopt(sb)->files[type])) {
  quota_error(sb, "Number of blocks too big for quota file size (%llu > %llu).",
      (loff_t)qinfo->dqi_blocks << qinfo->dqi_blocksize_bits,
      i_size_read(sb_dqopt(sb)->files[type]));
  goto out_free;
 }
 if (qinfo->dqi_free_blk && (qinfo->dqi_free_blk <= QT_TREEOFF ||
     qinfo->dqi_free_blk >= qinfo->dqi_blocks)) {
  quota_error(sb, "Free block number %u out of range (%u, %u).",
       qinfo->dqi_free_blk, QT_TREEOFF, qinfo->dqi_blocks);
  goto out_free;
 }
 if (qinfo->dqi_free_entry && (qinfo->dqi_free_entry <= QT_TREEOFF ||
     qinfo->dqi_free_entry >= qinfo->dqi_blocks)) {
  quota_error(sb, "Block with free entry %u out of range (%u, %u).",
       qinfo->dqi_free_entry, QT_TREEOFF,
       qinfo->dqi_blocks);
  goto out_free;
 }
 ret = 0;
out_free:
 if (ret) {
  kfree(info->dqi_priv);
  info->dqi_priv = NULL;
 }
out:
 memalloc_nofs_restore(memalloc);
 up_read(&dqopt->dqio_sem);
 return ret;
}

/* Write information header to quota file */
static int v2_write_file_info(struct super_block *sb, int type)
{
 struct v2_disk_dqinfo dinfo;
 struct quota_info *dqopt = sb_dqopt(sb);
 struct mem_dqinfo *info = &dqopt->info[type];
 struct qtree_mem_dqinfo *qinfo = info->dqi_priv;
 ssize_t size;
 unsigned int memalloc;

 down_write(&dqopt->dqio_sem);
 memalloc = memalloc_nofs_save();
 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);
 /* No flags currently supported */
 dinfo.dqi_flags = cpu_to_le32(0);
 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);
 memalloc_nofs_restore(memalloc);
 up_write(&dqopt->dqio_sem);
 if (size != sizeof(struct v2_disk_dqinfo)) {
  quota_error(sb, "Can't write info structure");
  return size < 0 ? size : -EIO;
 }
 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));
 d->dqb_pad = 0;
 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)
{
 struct quota_info *dqopt = sb_dqopt(dquot->dq_sb);
 int ret;
 unsigned int memalloc;

 down_read(&dqopt->dqio_sem);
 memalloc = memalloc_nofs_save();
 ret = qtree_read_dquot(
   sb_dqinfo(dquot->dq_sb, dquot->dq_id.type)->dqi_priv,
   dquot);
 memalloc_nofs_restore(memalloc);
 up_read(&dqopt->dqio_sem);
 return ret;
}

static int v2_write_dquot(struct dquot *dquot)
{
 struct quota_info *dqopt = sb_dqopt(dquot->dq_sb);
 int ret;
 bool alloc = false;
 unsigned int memalloc;

 /*
 * If space for dquot is already allocated, we don't need any
 * protection as we'll only overwrite the place of dquot. We are
 * still protected by concurrent writes of the same dquot by
 * dquot->dq_lock.
 */
 if (!dquot->dq_off) {
  alloc = true;
  down_write(&dqopt->dqio_sem);
 } else {
  down_read(&dqopt->dqio_sem);
 }
 memalloc = memalloc_nofs_save();
 ret = qtree_write_dquot(
   sb_dqinfo(dquot->dq_sb, dquot->dq_id.type)->dqi_priv,
   dquot);
 memalloc_nofs_restore(memalloc);
 if (alloc)
  up_write(&dqopt->dqio_sem);
 else
  up_read(&dqopt->dqio_sem);
 return ret;
}

static int v2_release_dquot(struct dquot *dquot)
{
 struct quota_info *dqopt = sb_dqopt(dquot->dq_sb);
 unsigned int memalloc;
 int ret;

 down_write(&dqopt->dqio_sem);
 memalloc = memalloc_nofs_save();
 ret = qtree_release_dquot(sb_dqinfo(dquot->dq_sb, dquot->dq_id.type)->dqi_priv, dquot);
 memalloc_nofs_restore(memalloc);
 up_write(&dqopt->dqio_sem);

 return ret;
}

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

static int v2_get_next_id(struct super_block *sb, struct kqid *qid)
{
 struct quota_info *dqopt = sb_dqopt(sb);
 unsigned int memalloc;
 int ret;

 down_read(&dqopt->dqio_sem);
 memalloc = memalloc_nofs_save();
 ret = qtree_get_next_id(sb_dqinfo(sb, qid->type)->dqi_priv, qid);
 memalloc_nofs_restore(memalloc);
 up_read(&dqopt->dqio_sem);
 return ret;
}

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,
 .get_next_id  = v2_get_next_id,
};

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)
{
 register_quota_format(&v2r0_quota_format);
 register_quota_format(&v2r1_quota_format);
 return 0;
}

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);