// 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;

  	int ret;

  	down_read(&dqopt->dqio_sem);

  	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_NOFS);
  	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;
  	}
  	if (qinfo->dqi_free_blk >= qinfo->dqi_blocks) {
  		quota_error(sb, "Free block number too big (%u >= %u).",
  			    qinfo->dqi_free_blk, qinfo->dqi_blocks);
  		goto out;
  	}
  	if (qinfo->dqi_free_entry >= qinfo->dqi_blocks) {
  		quota_error(sb, "Block with free entry too big (%u >= %u).",
  			    qinfo->dqi_free_entry, qinfo->dqi_blocks);
  		goto out;
  	}

  	ret = 0;
  out:
  	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;

  	down_write(&dqopt->dqio_sem);

  	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);

  	up_write(&dqopt->dqio_sem);

  	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));

  	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;
  
  	down_read(&dqopt->dqio_sem);
  	ret = qtree_read_dquot(
  			sb_dqinfo(dquot->dq_sb, dquot->dq_id.type)->dqi_priv,
  			dquot);
  	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;
  
  	/*
  	 * 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);

  	}

  	ret = qtree_write_dquot(
  			sb_dqinfo(dquot->dq_sb, dquot->dq_id.type)->dqi_priv,
  			dquot);

  	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);
  	int ret;
  
  	down_write(&dqopt->dqio_sem);
  	ret = qtree_release_dquot(sb_dqinfo(dquot->dq_sb, dquot->dq_id.type)->dqi_priv, dquot);
  	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);
  	int ret;
  
  	down_read(&dqopt->dqio_sem);
  	ret = qtree_get_next_id(sb_dqinfo(sb, qid->type)->dqi_priv, qid);
  	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)
  {

  	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);