fs/ntfs/lcnalloc.h

   1 /*
   2  * lcnalloc.h - Exports for NTFS kernel cluster (de)allocation.  Part of the
   3  *              Linux-NTFS project.
   4  *
   5  * Copyright (c) 2004-2005 Anton Altaparmakov
   6  *
   7  * This program/include file is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU General Public License as published
   9  * by the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program/include file is distributed in the hope that it will be
  13  * useful, but WITHOUT ANY WARRANTY; without even the implied warranty
  14  * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program (in the main directory of the Linux-NTFS
  19  * distribution in the file COPYING); if not, write to the Free Software
  20  * Foundation,Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  21  */
  22
  23 #ifndef _LINUX_NTFS_LCNALLOC_H
  24 #define _LINUX_NTFS_LCNALLOC_H
  25
  26 #ifdef NTFS_RW
  27
  28 #include <linux/fs.h>
  29
  30 #include "attrib.h"
  31 #include "types.h"
  32 #include "inode.h"
  33 #include "runlist.h"
  34 #include "volume.h"
  35
  36 typedef enum {
  37         FIRST_ZONE      = 0,    /* For sanity checking. */
  38         MFT_ZONE        = 0,    /* Allocate from $MFT zone. */
  39         DATA_ZONE       = 1,    /* Allocate from $DATA zone. */
  40         LAST_ZONE       = 1,    /* For sanity checking. */
  41 } NTFS_CLUSTER_ALLOCATION_ZONES;
  42
  43 extern runlist_element *ntfs_cluster_alloc(ntfs_volume *vol,
  44                 const VCN start_vcn, const s64 count, const LCN start_lcn,
  45                 const NTFS_CLUSTER_ALLOCATION_ZONES zone);
  46
  47 extern s64 __ntfs_cluster_free(ntfs_inode *ni, const VCN start_vcn,
  48                 s64 count, ntfs_attr_search_ctx *ctx, const BOOL is_rollback);
  49
  50 /**
  51  * ntfs_cluster_free - free clusters on an ntfs volume
  52  * @ni:         ntfs inode whose runlist describes the clusters to free
  53  * @start_vcn:  vcn in the runlist of @ni at which to start freeing clusters
  54  * @count:      number of clusters to free or -1 for all clusters
  55  * @ctx:        active attribute search context if present or NULL if not
  56  *
  57  * Free @count clusters starting at the cluster @start_vcn in the runlist
  58  * described by the ntfs inode @ni.
  59  *
  60  * If @count is -1, all clusters from @start_vcn to the end of the runlist are
  61  * deallocated.  Thus, to completely free all clusters in a runlist, use
  62  * @start_vcn = 0 and @count = -1.
  63  *
  64  * If @ctx is specified, it is an active search context of @ni and its base mft
  65  * record.  This is needed when ntfs_cluster_free() encounters unmapped runlist
  66  * fragments and allows their mapping.  If you do not have the mft record
  67  * mapped, you can specify @ctx as NULL and ntfs_cluster_free() will perform
  68  * the necessary mapping and unmapping.
  69  *
  70  * Note, ntfs_cluster_free() saves the state of @ctx on entry and restores it
  71  * before returning.  Thus, @ctx will be left pointing to the same attribute on
  72  * return as on entry.  However, the actual pointers in @ctx may point to
  73  * different memory locations on return, so you must remember to reset any
  74  * cached pointers from the @ctx, i.e. after the call to ntfs_cluster_free(),
  75  * you will probably want to do:
  76  *      m = ctx->mrec;
  77  *      a = ctx->attr;
  78  * Assuming you cache ctx->attr in a variable @a of type ATTR_RECORD * and that
  79  * you cache ctx->mrec in a variable @m of type MFT_RECORD *.
  80  *
  81  * Note, ntfs_cluster_free() does not modify the runlist, so you have to remove
  82  * from the runlist or mark sparse the freed runs later.
  83  *
  84  * Return the number of deallocated clusters (not counting sparse ones) on
  85  * success and -errno on error.
  86  *
  87  * WARNING: If @ctx is supplied, regardless of whether success or failure is
  88  *          returned, you need to check IS_ERR(@ctx->mrec) and if TRUE the @ctx
  89  *          is no longer valid, i.e. you need to either call
  90  *          ntfs_attr_reinit_search_ctx() or ntfs_attr_put_search_ctx() on it.
  91  *          In that case PTR_ERR(@ctx->mrec) will give you the error code for
  92  *          why the mapping of the old inode failed.
  93  *
  94  * Locking: - The runlist described by @ni must be locked for writing on entry
  95  *            and is locked on return.  Note the runlist may be modified when
  96  *            needed runlist fragments need to be mapped.
  97  *          - The volume lcn bitmap must be unlocked on entry and is unlocked
  98  *            on return.
  99  *          - This function takes the volume lcn bitmap lock for writing and
 100  *            modifies the bitmap contents.
 101  *          - If @ctx is NULL, the base mft record of @ni must not be mapped on
 102  *            entry and it will be left unmapped on return.
 103  *          - If @ctx is not NULL, the base mft record must be mapped on entry
 104  *            and it will be left mapped on return.
 105  */
 106 static inline s64 ntfs_cluster_free(ntfs_inode *ni, const VCN start_vcn,
 107                 s64 count, ntfs_attr_search_ctx *ctx)
 108 {
 109         return __ntfs_cluster_free(ni, start_vcn, count, ctx, FALSE);
 110 }
 111
 112 extern int ntfs_cluster_free_from_rl_nolock(ntfs_volume *vol,
 113                 const runlist_element *rl);
 114
 115 /**
 116  * ntfs_cluster_free_from_rl - free clusters from runlist
 117  * @vol:        mounted ntfs volume on which to free the clusters
 118  * @rl:         runlist describing the clusters to free
 119  *
 120  * Free all the clusters described by the runlist @rl on the volume @vol.  In
 121  * the case of an error being returned, at least some of the clusters were not
 122  * freed.
 123  *
 124  * Return 0 on success and -errno on error.
 125  *
 126  * Locking: - This function takes the volume lcn bitmap lock for writing and
 127  *            modifies the bitmap contents.
 128  *          - The caller must have locked the runlist @rl for reading or
 129  *            writing.
 130  */
 131 static inline int ntfs_cluster_free_from_rl(ntfs_volume *vol,
 132                 const runlist_element *rl)
 133 {
 134         int ret;
 135
 136         down_write(&vol->lcnbmp_lock);
 137         ret = ntfs_cluster_free_from_rl_nolock(vol, rl);
 138         up_write(&vol->lcnbmp_lock);
 139         return ret;
 140 }
 141
 142 #endif /* NTFS_RW */
 143
 144 #endif /* defined _LINUX_NTFS_LCNALLOC_H */