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 /* 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 */

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