diff options
Diffstat (limited to 'fs/ntfs/lcnalloc.h')
| -rw-r--r-- | fs/ntfs/lcnalloc.h | 40 |
1 files changed, 35 insertions, 5 deletions
diff --git a/fs/ntfs/lcnalloc.h b/fs/ntfs/lcnalloc.h index a6a8827882e..aa0518509cd 100644 --- a/fs/ntfs/lcnalloc.h +++ b/fs/ntfs/lcnalloc.h @@ -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, |