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NTFS: - Change {__,}ntfs_cluster_free() to also take an optional attribute

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search context as argument.  This allows calling it with the mft
        record mapped.  Update all callers.
      - Fix potential deadlock in ntfs_mft_data_extend_allocation_nolock()
	error handling by passing in the active search context when calling
	ntfs_cluster_free().

Signed-off-by: Anton Altaparmakov <aia21@cantab.net>
This commit is contained in:
Anton Altaparmakov
2005-10-04 14:24:21 +01:00
parent 69b41e3c02
commit 511bea5ea2
4 changed files with 86 additions and 19 deletions
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40
fs/ntfs/lcnalloc.h
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@@ -27,6 +27,7 @@
#include <linux/fs.h>
#include "attrib.h"
#include "types.h"
#include "inode.h"
#include "runlist.h"
@@ -44,13 +45,14 @@ extern runlist_element *ntfs_cluster_alloc(ntfs_volume *vol,
const NTFS_CLUSTER_ALLOCATION_ZONES zone);
extern s64 __ntfs_cluster_free(ntfs_inode *ni, const VCN start_vcn,
s64 count, const BOOL is_rollback);
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.
@@ -59,12 +61,36 @@ extern s64 __ntfs_cluster_free(ntfs_inode *ni, const VCN start_vcn,
* deallocated. Thus, to completely free all clusters in a runlist, use
* @start_vcn = 0 and @count = -1.
*
* Note, ntfs_cluster_free() does not modify the runlist at all, so the caller
* has to deal with it later.
* 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.
@@ -72,11 +98,15 @@ extern s64 __ntfs_cluster_free(ntfs_inode *ni, const VCN start_vcn,
* 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)
s64 count, ntfs_attr_search_ctx *ctx)
{
return __ntfs_cluster_free(ni, start_vcn, count, FALSE);
return __ntfs_cluster_free(ni, start_vcn, count, ctx, FALSE);
}
extern int ntfs_cluster_free_from_rl_nolock(ntfs_volume *vol,