gfile: Eliminate a stat() call from the file copy code

The start of the `g_file_copy()` implementation stats the source file to find all the attributes to copy onto the destination file, so it makes sense to get it to store the source file size at the same time. This saves a subsequent `stat()` call on the source FD in the btrfs reflink or splice code. Every little helps. Signed-off-by: Philip Withnall <[email protected]>
GNOME · May 9, 2023 · 0da948a · 0da948a
1 parent 63e1e83
commit 0da948a
Showing 1 changed file with 13 additions and 10 deletions.
diff --git a/gio/gfile.c b/gio/gfile.c
@@ -2807,6 +2807,11 @@ g_file_build_attribute_list_for_copy (GFile                  *file,
   first = TRUE;
   s = g_string_new ("");
 
+  /* Always query the source file size, even though we can’t set that on the
+   * destination. This is useful for the copy functions. */
+  first = FALSE;
+  g_string_append (s, G_FILE_ATTRIBUTE_STANDARD_SIZE);
+
   if (attributes)
     {
       for (i = 0; i < attributes->n_infos; i++)
@@ -3042,6 +3047,7 @@ do_splice (int     fd_in,
 
 static gboolean
 splice_stream_with_progress (GInputStream           *in,
+                             GFileInfo              *in_info,
                              GOutputStream          *out,
                              GCancellable           *cancellable,
                              GFileProgressCallback   progress_callback,
@@ -3085,10 +3091,8 @@ splice_stream_with_progress (GInputStream           *in,
   /* avoid performance impact of querying total size when it's not needed */
   if (progress_callback)
     {
-      struct stat sbuf;
-
-      if (fstat (fd_in, &sbuf) == 0)
-        total_size = sbuf.st_size;
+      g_assert (g_file_info_has_attribute (in_info, G_FILE_ATTRIBUTE_STANDARD_SIZE));
+      total_size = g_file_info_get_size (in_info);
     }
 
   if (total_size == -1)
@@ -3151,6 +3155,7 @@ splice_stream_with_progress (GInputStream           *in,
 #ifdef __linux__
 static gboolean
 btrfs_reflink_with_progress (GInputStream           *in,
+                             GFileInfo              *in_info,
                              GOutputStream          *out,
                              GFileInfo              *info,
                              GCancellable           *cancellable,
@@ -3169,10 +3174,8 @@ btrfs_reflink_with_progress (GInputStream           *in,
   /* avoid performance impact of querying total size when it's not needed */
   if (progress_callback)
     {
-      struct stat sbuf;
-
-      if (fstat (fd_in, &sbuf) == 0)
-        total_size = sbuf.st_size;
+      g_assert (g_file_info_has_attribute (in_info, G_FILE_ATTRIBUTE_STANDARD_SIZE));
+      total_size = g_file_info_get_size (in_info);
     }
 
   if (total_size == -1)
@@ -3376,7 +3379,7 @@ file_copy_fallback (GFile                  *source,
     {
       GError *reflink_err = NULL;
 
-      if (!btrfs_reflink_with_progress (in, out, info, cancellable,
+      if (!btrfs_reflink_with_progress (in, info, out, info, cancellable,
                                         progress_callback, progress_callback_data,
                                         &reflink_err))
         {
@@ -3403,7 +3406,7 @@ file_copy_fallback (GFile                  *source,
     {
       GError *splice_err = NULL;
 
-      if (!splice_stream_with_progress (in, out, cancellable,
+      if (!splice_stream_with_progress (in, info, out, cancellable,
                                         progress_callback, progress_callback_data,
                                         &splice_err))
         {