diff options
Diffstat (limited to 'fs/ntfs/lcnalloc.c')
| -rw-r--r-- | fs/ntfs/lcnalloc.c | 41 |
1 files changed, 35 insertions, 6 deletions
diff --git a/fs/ntfs/lcnalloc.c b/fs/ntfs/lcnalloc.c index 8e60c47fafa..75313f4307e 100644 --- a/fs/ntfs/lcnalloc.c +++ b/fs/ntfs/lcnalloc.c @@ -782,6 +782,7 @@ out: * @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 * @is_rollback: true if this is a rollback operation * * Free @count clusters starting at the cluster @start_vcn in the runlist @@ -791,15 +792,39 @@ out: * 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 *. + * * @is_rollback should always be FALSE, it is for internal use to rollback * errors. You probably want to use ntfs_cluster_free() instead. * - * Note, ntfs_cluster_free() does not modify the runlist at all, so the caller - * has to deal with it later. + * 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mrec) and if TRUE the @ctx + * is no longer valid, i.e. you need to either call + * ntfs_attr_reinit_search_ctx() or ntfs_attr_put_search_ctx() on it.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. @@ -807,9 +832,13 @@ out: * 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. */ s64 __ntfs_cluster_free(ntfs_inode *ni, const VCN start_vcn, s64 count, - const BOOL is_rollback) + ntfs_attr_search_ctx *ctx, const BOOL is_rollback) { s64 delta, to_free, total_freed, real_freed; ntfs_volume *vol; @@ -839,7 +868,7 @@ s64 __ntfs_cluster_free(ntfs_inode *ni, const VCN start_vcn, s64 count, total_freed = real_freed = 0; - rl = ntfs_attr_find_vcn_nolock(ni, start_vcn, NULL); + rl = ntfs_attr_find_vcn_nolock(ni, start_vcn, ctx); if (IS_ERR(rl)) { if (!is_rollback) ntfs_error(vol->sb, "Failed to find first runlist " @@ -893,7 +922,7 @@ s64 __ntfs_cluster_free(ntfs_inode *ni, const VCN start_vcn, s64 count, /* Attempt to map runlist. */ vcn = rl->vcn; - rl = ntfs_attr_find_vcn_nolock(ni, vcn, NULL); + rl = ntfs_attr_find_vcn_nolock(ni, vcn, ctx); if (IS_ERR(rl)) { err = PTR_ERR(rl); if (!is_rollback) @@ -961,7 +990,7 @@ err_out: * If rollback fails, set the volume errors flag, emit an error * message, and return the error code. */ - delta = __ntfs_cluster_free(ni, start_vcn, total_freed, TRUE); + delta = __ntfs_cluster_free(ni, start_vcn, total_freed, ctx, TRUE); if (delta < 0) { ntfs_error(vol->sb, "Failed to rollback (error %i). Leaving " "inconsistent metadata! Unmount and run " |