/* SPDX-License-Identifier: GPL-2.0 */

  /*
   * Copyright (C) 1995, 1996, 1997 Olaf Kirch <okir@monad.swb.de>
   *
   * This file describes the layout of the file handles as passed
   * over the wire.
   */
  #ifndef _LINUX_NFSD_NFSFH_H
  #define _LINUX_NFSD_NFSFH_H

  #include <linux/crc32.h>

  #include <linux/sunrpc/svc.h>
  #include <uapi/linux/nfsd/nfsfh.h>

  #include <linux/iversion.h>

  
  static inline __u32 ino_t_to_u32(ino_t ino)
  {
  	return (__u32) ino;
  }
  
  static inline ino_t u32_to_ino_t(__u32 uino)
  {
  	return (ino_t) uino;
  }

  /*
   * This is the internal representation of an NFS handle used in knfsd.
   * pre_mtime/post_version will be used to support wcc_attr's in NFSv3.
   */
  typedef struct svc_fh {
  	struct knfsd_fh		fh_handle;	/* FH data */

  	int			fh_maxsize;	/* max size for fh_handle */

  	struct dentry *		fh_dentry;	/* validated dentry */
  	struct svc_export *	fh_export;	/* export pointer */

  	bool			fh_locked;	/* inode locked by us */
  	bool			fh_want_write;	/* remount protection taken */

  
  #ifdef CONFIG_NFSD_V3

  	bool			fh_post_saved;	/* post-op attrs saved */
  	bool			fh_pre_saved;	/* pre-op attrs saved */

  
  	/* Pre-op attributes saved during fh_lock */
  	__u64			fh_pre_size;	/* size before operation */
  	struct timespec		fh_pre_mtime;	/* mtime before oper */
  	struct timespec		fh_pre_ctime;	/* ctime before oper */
  	/*
  	 * pre-op nfsv4 change attr: note must check IS_I_VERSION(inode)
  	 *  to find out if it is valid.
  	 */
  	u64			fh_pre_change;
  
  	/* Post-op attributes saved in fh_unlock */
  	struct kstat		fh_post_attr;	/* full attrs after operation */
  	u64			fh_post_change; /* nfsv4 change; see above */
  #endif /* CONFIG_NFSD_V3 */

  } svc_fh;

  
  enum nfsd_fsid {
  	FSID_DEV = 0,
  	FSID_NUM,
  	FSID_MAJOR_MINOR,
  	FSID_ENCODE_DEV,
  	FSID_UUID4_INUM,
  	FSID_UUID8,
  	FSID_UUID16,
  	FSID_UUID16_INUM,
  };
  
  enum fsid_source {
  	FSIDSOURCE_DEV,
  	FSIDSOURCE_FSID,
  	FSIDSOURCE_UUID,
  };
  extern enum fsid_source fsid_source(struct svc_fh *fhp);

  /*
   * This might look a little large to "inline" but in all calls except

   * one, 'vers' is constant so moste of the function disappears.

   *
   * In some cases the values are considered to be host endian and in
   * others, net endian. fsidv is always considered to be u32 as the
   * callers don't know which it will be. So we must use __force to keep
   * sparse from complaining. Since these values are opaque to the
   * client, that shouldn't be a problem.

   */
  static inline void mk_fsid(int vers, u32 *fsidv, dev_t dev, ino_t ino,
  			   u32 fsid, unsigned char *uuid)
  {
  	u32 *up;
  	switch(vers) {
  	case FSID_DEV:

  		fsidv[0] = (__force __u32)htonl((MAJOR(dev)<<16) |

  				 MINOR(dev));
  		fsidv[1] = ino_t_to_u32(ino);
  		break;
  	case FSID_NUM:
  		fsidv[0] = fsid;
  		break;
  	case FSID_MAJOR_MINOR:

  		fsidv[0] = (__force __u32)htonl(MAJOR(dev));
  		fsidv[1] = (__force __u32)htonl(MINOR(dev));

  		fsidv[2] = ino_t_to_u32(ino);
  		break;
  
  	case FSID_ENCODE_DEV:
  		fsidv[0] = new_encode_dev(dev);
  		fsidv[1] = ino_t_to_u32(ino);
  		break;
  
  	case FSID_UUID4_INUM:
  		/* 4 byte fsid and inode number */
  		up = (u32*)uuid;
  		fsidv[0] = ino_t_to_u32(ino);
  		fsidv[1] = up[0] ^ up[1] ^ up[2] ^ up[3];
  		break;
  
  	case FSID_UUID8:
  		/* 8 byte fsid  */
  		up = (u32*)uuid;
  		fsidv[0] = up[0] ^ up[2];
  		fsidv[1] = up[1] ^ up[3];
  		break;
  
  	case FSID_UUID16:
  		/* 16 byte fsid - NFSv3+ only */
  		memcpy(fsidv, uuid, 16);
  		break;
  
  	case FSID_UUID16_INUM:
  		/* 8 byte inode and 16 byte fsid */
  		*(u64*)fsidv = (u64)ino;
  		memcpy(fsidv+2, uuid, 16);
  		break;
  	default: BUG();
  	}
  }
  
  static inline int key_len(int type)
  {
  	switch(type) {
  	case FSID_DEV:		return 8;
  	case FSID_NUM: 		return 4;
  	case FSID_MAJOR_MINOR:	return 12;
  	case FSID_ENCODE_DEV:	return 8;
  	case FSID_UUID4_INUM:	return 8;
  	case FSID_UUID8:	return 8;
  	case FSID_UUID16:	return 16;
  	case FSID_UUID16_INUM:	return 24;
  	default: return 0;
  	}
  }
  
  /*
   * Shorthand for dprintk()'s
   */
  extern char * SVCFH_fmt(struct svc_fh *fhp);
  
  /*
   * Function prototypes
   */

  __be32	fh_verify(struct svc_rqst *, struct svc_fh *, umode_t, int);

  __be32	fh_compose(struct svc_fh *, struct svc_export *, struct dentry *, struct svc_fh *);
  __be32	fh_update(struct svc_fh *);
  void	fh_put(struct svc_fh *);
  
  static __inline__ struct svc_fh *
  fh_copy(struct svc_fh *dst, struct svc_fh *src)
  {
  	WARN_ON(src->fh_dentry || src->fh_locked);
  			
  	*dst = *src;
  	return dst;
  }
  
  static inline void
  fh_copy_shallow(struct knfsd_fh *dst, struct knfsd_fh *src)
  {
  	dst->fh_size = src->fh_size;
  	memcpy(&dst->fh_base, &src->fh_base, src->fh_size);
  }
  
  static __inline__ struct svc_fh *
  fh_init(struct svc_fh *fhp, int maxsize)
  {
  	memset(fhp, 0, sizeof(*fhp));
  	fhp->fh_maxsize = maxsize;
  	return fhp;
  }

  static inline bool fh_match(struct knfsd_fh *fh1, struct knfsd_fh *fh2)
  {
  	if (fh1->fh_size != fh2->fh_size)
  		return false;
  	if (memcmp(fh1->fh_base.fh_pad, fh2->fh_base.fh_pad, fh1->fh_size) != 0)
  		return false;
  	return true;
  }

  static inline bool fh_fsid_match(struct knfsd_fh *fh1, struct knfsd_fh *fh2)
  {
  	if (fh1->fh_fsid_type != fh2->fh_fsid_type)
  		return false;

  	if (memcmp(fh1->fh_fsid, fh2->fh_fsid, key_len(fh1->fh_fsid_type)) != 0)

  		return false;
  	return true;
  }

  #ifdef CONFIG_CRC32
  /**
   * knfsd_fh_hash - calculate the crc32 hash for the filehandle
   * @fh - pointer to filehandle
   *
   * returns a crc32 hash for the filehandle that is compatible with
   * the one displayed by "wireshark".
   */
  
  static inline u32
  knfsd_fh_hash(struct knfsd_fh *fh)
  {
  	return ~crc32_le(0xFFFFFFFF, (unsigned char *)&fh->fh_base, fh->fh_size);
  }
  #else
  static inline u32
  knfsd_fh_hash(struct knfsd_fh *fh)
  {
  	return 0;
  }
  #endif

  #ifdef CONFIG_NFSD_V3
  /*

   * The wcc data stored in current_fh should be cleared
   * between compound ops.
   */
  static inline void
  fh_clear_wcc(struct svc_fh *fhp)
  {

  	fhp->fh_post_saved = false;
  	fhp->fh_pre_saved = false;

  }
  
  /*

   * We could use i_version alone as the change attribute.  However,
   * i_version can go backwards after a reboot.  On its own that doesn't
   * necessarily cause a problem, but if i_version goes backwards and then
   * is incremented again it could reuse a value that was previously used
   * before boot, and a client who queried the two values might
   * incorrectly assume nothing changed.
   *
   * By using both ctime and the i_version counter we guarantee that as
   * long as time doesn't go backwards we never reuse an old value.
   */

  static inline u64 nfsd4_change_attribute(struct kstat *stat,
  					 struct inode *inode)

  {
  	u64 chattr;

  	chattr =  stat->ctime.tv_sec;

  	chattr <<= 30;

  	chattr += stat->ctime.tv_nsec;

  	chattr += inode_query_iversion(inode);

  	return chattr;
  }

  extern void fill_pre_wcc(struct svc_fh *fhp);
  extern void fill_post_wcc(struct svc_fh *fhp);

  #else

  #define fh_clear_wcc(ignored)
  #define fill_pre_wcc(ignored)

  #define fill_post_wcc(notused)
  #endif /* CONFIG_NFSD_V3 */
  
  
  /*
   * Lock a file handle/inode
   * NOTE: both fh_lock and fh_unlock are done "by hand" in
   * vfs.c:nfsd_rename as it needs to grab 2 i_mutex's at once
   * so, any changes here should be reflected there.
   */
  
  static inline void
  fh_lock_nested(struct svc_fh *fhp, unsigned int subclass)
  {
  	struct dentry	*dentry = fhp->fh_dentry;
  	struct inode	*inode;
  
  	BUG_ON(!dentry);
  
  	if (fhp->fh_locked) {

  		printk(KERN_WARNING "fh_lock: %pd2 already locked!
  ",
  			dentry);

  		return;
  	}

  	inode = d_inode(dentry);

  	inode_lock_nested(inode, subclass);

  	fill_pre_wcc(fhp);

  	fhp->fh_locked = true;

  }
  
  static inline void
  fh_lock(struct svc_fh *fhp)
  {
  	fh_lock_nested(fhp, I_MUTEX_NORMAL);
  }
  
  /*
   * Unlock a file handle/inode
   */
  static inline void
  fh_unlock(struct svc_fh *fhp)
  {

  	if (fhp->fh_locked) {
  		fill_post_wcc(fhp);

  		inode_unlock(d_inode(fhp->fh_dentry));

  		fhp->fh_locked = false;

  	}
  }

  #endif /* _LINUX_NFSD_NFSFH_H */