win32_apply.c: Allocate space just before writing each stream
authorEric Biggers <ebiggers3@gmail.com>
Thu, 22 May 2014 19:16:01 +0000 (14:16 -0500)
committerEric Biggers <ebiggers3@gmail.com>
Thu, 22 May 2014 19:16:01 +0000 (14:16 -0500)
This seems to give better performance compared to allocating space when
each file is created.

src/win32_apply.c

index fcb2c00..421db26 100644 (file)
@@ -985,22 +985,6 @@ create_directories(struct list_head *dentry_list,
        return 0;
 }
 
-/* Gets the number of bytes to allocate for the specified inode.  */
-static void
-inode_get_allocation_size(const struct wim_inode *inode,
-                         LARGE_INTEGER *allocation_size_ret)
-{
-       const struct wim_lookup_table_entry *unnamed_stream;
-
-       /* We just count the unnamed data stream.  */
-
-       unnamed_stream = inode_unnamed_lte_resolved(inode);
-       if (unnamed_stream)
-               allocation_size_ret->QuadPart = unnamed_stream->size;
-       else
-               allocation_size_ret->QuadPart = 0;
-}
-
 /*
  * Creates the nondirectory file named by @dentry.
  *
@@ -1013,17 +997,12 @@ create_nondirectory_inode(HANDLE *h_ret, const struct wim_dentry *dentry,
                          struct win32_apply_ctx *ctx)
 {
        const struct wim_inode *inode;
-       LARGE_INTEGER allocation_size;
        ULONG attrib;
        NTSTATUS status;
        bool retried = false;
 
        inode = dentry->d_inode;
 
-       /* To increase performance, we will pre-allocate space for the file
-        * data.  */
-       inode_get_allocation_size(inode, &allocation_size);
-
        /* If the file already exists and has FILE_ATTRIBUTE_SYSTEM and/or
         * FILE_ATTRIBUTE_HIDDEN, these must be specified in order to supersede
         * the file.
@@ -1049,7 +1028,7 @@ create_nondirectory_inode(HANDLE *h_ret, const struct wim_dentry *dentry,
        build_extraction_path(dentry, ctx);
 retry:
        status = do_create_file(h_ret, GENERIC_READ | GENERIC_WRITE | DELETE,
-                               &allocation_size, attrib, FILE_SUPERSEDE,
+                               NULL, attrib, FILE_SUPERSEDE,
                                FILE_NON_DIRECTORY_FILE, ctx);
        if (NT_SUCCESS(status)) {
                int ret;
@@ -1291,7 +1270,7 @@ begin_extract_stream_instance(const struct wim_lookup_table_entry *stream,
 {
        const struct wim_inode *inode = dentry->d_inode;
        size_t stream_name_nchars = 0;
-       LARGE_INTEGER allocation_size;
+       FILE_ALLOCATION_INFORMATION alloc_info;
        HANDLE h;
        NTSTATUS status;
 
@@ -1383,10 +1362,9 @@ begin_extract_stream_instance(const struct wim_lookup_table_entry *stream,
        }
 
        /* Open a new handle  */
-       allocation_size.QuadPart = stream->size;
        status = do_create_file(&h,
                                FILE_WRITE_DATA | SYNCHRONIZE,
-                               &allocation_size, 0, FILE_OPEN_IF,
+                               NULL, 0, FILE_OPEN_IF,
                                FILE_SEQUENTIAL_ONLY |
                                        FILE_SYNCHRONOUS_IO_NONALERT,
                                ctx);
@@ -1399,6 +1377,12 @@ begin_extract_stream_instance(const struct wim_lookup_table_entry *stream,
        }
 
        ctx->open_handles[ctx->num_open_handles++] = h;
+
+       /* Allocate space for the data.  */
+       alloc_info.AllocationSize.QuadPart = stream->size;
+       (*func_NtSetInformationFile)(h, &ctx->iosb,
+                                    &alloc_info, sizeof(alloc_info),
+                                    FileAllocationInformation);
        return 0;
 }