132 lines
4.9 KiB
C
132 lines
4.9 KiB
C
/* SPDX-License-Identifier: GPL-2.0-or-later */
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/*
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* lcnalloc.h - Exports for NTFS kernel cluster (de)allocation. Part of the
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* Linux-NTFS project.
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*
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* Copyright (c) 2004-2005 Anton Altaparmakov
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*/
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#ifndef _LINUX_NTFS_LCNALLOC_H
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#define _LINUX_NTFS_LCNALLOC_H
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#ifdef NTFS_RW
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#include <linux/fs.h>
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#include "attrib.h"
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#include "types.h"
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#include "inode.h"
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#include "runlist.h"
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#include "volume.h"
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typedef enum {
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FIRST_ZONE = 0, /* For sanity checking. */
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MFT_ZONE = 0, /* Allocate from $MFT zone. */
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DATA_ZONE = 1, /* Allocate from $DATA zone. */
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LAST_ZONE = 1, /* For sanity checking. */
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} NTFS_CLUSTER_ALLOCATION_ZONES;
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extern runlist_element *ntfs_cluster_alloc(ntfs_volume *vol,
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const VCN start_vcn, const s64 count, const LCN start_lcn,
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const NTFS_CLUSTER_ALLOCATION_ZONES zone,
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const bool is_extension);
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extern s64 __ntfs_cluster_free(ntfs_inode *ni, const VCN start_vcn,
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s64 count, ntfs_attr_search_ctx *ctx, const bool is_rollback);
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/**
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* ntfs_cluster_free - free clusters on an ntfs volume
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* @ni: ntfs inode whose runlist describes the clusters to free
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* @start_vcn: vcn in the runlist of @ni at which to start freeing clusters
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* @count: number of clusters to free or -1 for all clusters
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* @ctx: active attribute search context if present or NULL if not
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*
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* Free @count clusters starting at the cluster @start_vcn in the runlist
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* described by the ntfs inode @ni.
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*
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* If @count is -1, all clusters from @start_vcn to the end of the runlist are
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* deallocated. Thus, to completely free all clusters in a runlist, use
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* @start_vcn = 0 and @count = -1.
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*
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* If @ctx is specified, it is an active search context of @ni and its base mft
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* record. This is needed when ntfs_cluster_free() encounters unmapped runlist
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* fragments and allows their mapping. If you do not have the mft record
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* mapped, you can specify @ctx as NULL and ntfs_cluster_free() will perform
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* the necessary mapping and unmapping.
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*
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* Note, ntfs_cluster_free() saves the state of @ctx on entry and restores it
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* before returning. Thus, @ctx will be left pointing to the same attribute on
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* return as on entry. However, the actual pointers in @ctx may point to
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* different memory locations on return, so you must remember to reset any
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* cached pointers from the @ctx, i.e. after the call to ntfs_cluster_free(),
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* you will probably want to do:
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* m = ctx->mrec;
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* a = ctx->attr;
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* Assuming you cache ctx->attr in a variable @a of type ATTR_RECORD * and that
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* you cache ctx->mrec in a variable @m of type MFT_RECORD *.
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*
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* Note, ntfs_cluster_free() does not modify the runlist, so you have to remove
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* from the runlist or mark sparse the freed runs later.
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*
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* Return the number of deallocated clusters (not counting sparse ones) on
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* success and -errno on error.
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*
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* WARNING: If @ctx is supplied, regardless of whether success or failure is
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* returned, you need to check IS_ERR(@ctx->mrec) and if 'true' the @ctx
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* is no longer valid, i.e. you need to either call
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* ntfs_attr_reinit_search_ctx() or ntfs_attr_put_search_ctx() on it.
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* In that case PTR_ERR(@ctx->mrec) will give you the error code for
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* why the mapping of the old inode failed.
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*
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* Locking: - The runlist described by @ni must be locked for writing on entry
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* and is locked on return. Note the runlist may be modified when
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* needed runlist fragments need to be mapped.
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* - The volume lcn bitmap must be unlocked on entry and is unlocked
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* on return.
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* - This function takes the volume lcn bitmap lock for writing and
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* modifies the bitmap contents.
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* - If @ctx is NULL, the base mft record of @ni must not be mapped on
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* entry and it will be left unmapped on return.
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* - If @ctx is not NULL, the base mft record must be mapped on entry
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* and it will be left mapped on return.
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*/
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static inline s64 ntfs_cluster_free(ntfs_inode *ni, const VCN start_vcn,
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s64 count, ntfs_attr_search_ctx *ctx)
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{
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return __ntfs_cluster_free(ni, start_vcn, count, ctx, false);
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}
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extern int ntfs_cluster_free_from_rl_nolock(ntfs_volume *vol,
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const runlist_element *rl);
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/**
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* ntfs_cluster_free_from_rl - free clusters from runlist
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* @vol: mounted ntfs volume on which to free the clusters
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* @rl: runlist describing the clusters to free
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*
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* Free all the clusters described by the runlist @rl on the volume @vol. In
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* the case of an error being returned, at least some of the clusters were not
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* freed.
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*
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* Return 0 on success and -errno on error.
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*
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* Locking: - This function takes the volume lcn bitmap lock for writing and
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* modifies the bitmap contents.
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* - The caller must have locked the runlist @rl for reading or
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* writing.
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*/
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static inline int ntfs_cluster_free_from_rl(ntfs_volume *vol,
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const runlist_element *rl)
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{
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int ret;
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down_write(&vol->lcnbmp_lock);
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ret = ntfs_cluster_free_from_rl_nolock(vol, rl);
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up_write(&vol->lcnbmp_lock);
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return ret;
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}
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#endif /* NTFS_RW */
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#endif /* defined _LINUX_NTFS_LCNALLOC_H */
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