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

  /*
   * lcnalloc.h - Exports for NTFS kernel cluster (de)allocation.  Part of the
   *		Linux-NTFS project.
   *

   * Copyright (c) 2004-2005 Anton Altaparmakov

   */
  
  #ifndef _LINUX_NTFS_LCNALLOC_H
  #define _LINUX_NTFS_LCNALLOC_H
  
  #ifdef NTFS_RW
  
  #include <linux/fs.h>

  #include "attrib.h"

  #include "types.h"

  #include "inode.h"

  #include "runlist.h"
  #include "volume.h"
  
  typedef enum {
  	FIRST_ZONE	= 0,	/* For sanity checking. */
  	MFT_ZONE	= 0,	/* Allocate from $MFT zone. */
  	DATA_ZONE	= 1,	/* Allocate from $DATA zone. */
  	LAST_ZONE	= 1,	/* For sanity checking. */
  } NTFS_CLUSTER_ALLOCATION_ZONES;
  
  extern runlist_element *ntfs_cluster_alloc(ntfs_volume *vol,
  		const VCN start_vcn, const s64 count, const LCN start_lcn,

  		const NTFS_CLUSTER_ALLOCATION_ZONES zone,

  		const bool is_extension);

  extern s64 __ntfs_cluster_free(ntfs_inode *ni, const VCN start_vcn,

  		s64 count, ntfs_attr_search_ctx *ctx, const bool is_rollback);

  
  /**
   * ntfs_cluster_free - free clusters on an ntfs volume

   * @ni:		ntfs inode whose runlist describes the clusters to free
   * @start_vcn:	vcn in the runlist of @ni at which to start freeing clusters

   * @count:	number of clusters to free or -1 for all clusters

   * @ctx:	active attribute search context if present or NULL if not

   *
   * Free @count clusters starting at the cluster @start_vcn in the runlist

   * described by the ntfs inode @ni.

   *
   * If @count is -1, all clusters from @start_vcn to the end of the runlist are
   * deallocated.  Thus, to completely free all clusters in a runlist, use
   * @start_vcn = 0 and @count = -1.
   *

   * If @ctx is specified, it is an active search context of @ni and its base mft
   * record.  This is needed when ntfs_cluster_free() encounters unmapped runlist
   * fragments and allows their mapping.  If you do not have the mft record
   * mapped, you can specify @ctx as NULL and ntfs_cluster_free() will perform
   * the necessary mapping and unmapping.
   *
   * Note, ntfs_cluster_free() saves the state of @ctx on entry and restores it
   * before returning.  Thus, @ctx will be left pointing to the same attribute on
   * return as on entry.  However, the actual pointers in @ctx may point to
   * different memory locations on return, so you must remember to reset any
   * cached pointers from the @ctx, i.e. after the call to ntfs_cluster_free(),
   * you will probably want to do:
   *	m = ctx->mrec;
   *	a = ctx->attr;
   * Assuming you cache ctx->attr in a variable @a of type ATTR_RECORD * and that
   * you cache ctx->mrec in a variable @m of type MFT_RECORD *.
   *
   * Note, ntfs_cluster_free() does not modify the runlist, so you have to remove
   * from the runlist or mark sparse the freed runs later.

   *
   * Return the number of deallocated clusters (not counting sparse ones) on
   * success and -errno on error.
   *

   * WARNING: If @ctx is supplied, regardless of whether success or failure is

   *	    returned, you need to check IS_ERR(@ctx->mrec) and if 'true' the @ctx

   *	    is no longer valid, i.e. you need to either call
   *	    ntfs_attr_reinit_search_ctx() or ntfs_attr_put_search_ctx() on it.
   *	    In that case PTR_ERR(@ctx->mrec) will give you the error code for
   *	    why the mapping of the old inode failed.
   *

   * Locking: - The runlist described by @ni must be locked for writing on entry
   *	      and is locked on return.  Note the runlist may be modified when
   *	      needed runlist fragments need to be mapped.

   *	    - The volume lcn bitmap must be unlocked on entry and is unlocked
   *	      on return.
   *	    - This function takes the volume lcn bitmap lock for writing and
   *	      modifies the bitmap contents.

   *	    - If @ctx is NULL, the base mft record of @ni must not be mapped on
   *	      entry and it will be left unmapped on return.
   *	    - If @ctx is not NULL, the base mft record must be mapped on entry
   *	      and it will be left mapped on return.

   */

  static inline s64 ntfs_cluster_free(ntfs_inode *ni, const VCN start_vcn,

  		s64 count, ntfs_attr_search_ctx *ctx)

  {

  	return __ntfs_cluster_free(ni, start_vcn, count, ctx, false);

  }
  
  extern int ntfs_cluster_free_from_rl_nolock(ntfs_volume *vol,
  		const runlist_element *rl);
  
  /**
   * ntfs_cluster_free_from_rl - free clusters from runlist
   * @vol:	mounted ntfs volume on which to free the clusters
   * @rl:		runlist describing the clusters to free
   *
   * Free all the clusters described by the runlist @rl on the volume @vol.  In
   * the case of an error being returned, at least some of the clusters were not
   * freed.
   *
   * Return 0 on success and -errno on error.
   *

   * Locking: - This function takes the volume lcn bitmap lock for writing and
   *	      modifies the bitmap contents.
   *	    - The caller must have locked the runlist @rl for reading or
   *	      writing.

   */
  static inline int ntfs_cluster_free_from_rl(ntfs_volume *vol,
  		const runlist_element *rl)
  {
  	int ret;
  
  	down_write(&vol->lcnbmp_lock);
  	ret = ntfs_cluster_free_from_rl_nolock(vol, rl);
  	up_write(&vol->lcnbmp_lock);
  	return ret;
  }
  
  #endif /* NTFS_RW */
  
  #endif /* defined _LINUX_NTFS_LCNALLOC_H */