@@ -62,6 +62,15 @@ struct writeback_control {
unsigned for_writepages:1; /* This is a writepages() call */
unsigned range_cyclic:1; /* range_start is cyclic */
unsigned more_io:1; /* more io to be dispatched */
+ /*
+ * write_cache_pages() won't update wbc->nr_to_write and
+ * mapping->writeback_index if no_nrwrite_index_update
+ * is set. write_cache_pages() may write more than we
+ * requested and we want to make sure nr_to_write and
+ * writeback_index are updated in a consistent manner
+ * so we use a single control to update them
+ */
+ unsigned no_nrwrite_index_update:1;
};
/*
@@ -878,6 +878,7 @@ int write_cache_pages(struct address_spa
pgoff_t done_index;
int cycled;
int range_whole = 0;
+ long nr_to_write = wbc->nr_to_write;
if (wbc->nonblocking && bdi_write_congested(bdi)) {
wbc->encountered_congestion = 1;
@@ -985,9 +986,9 @@ continue_unlock:
}
}
- if (wbc->nr_to_write > 0) {
- wbc->nr_to_write--;
- if (wbc->nr_to_write == 0 &&
+ if (nr_to_write > 0) {
+ nr_to_write--;
+ if (nr_to_write == 0 &&
wbc->sync_mode == WB_SYNC_NONE) {
/*
* We stop writing back only if we are
@@ -1024,8 +1025,11 @@ continue_unlock:
end = writeback_index - 1;
goto retry;
}
- if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0))
- mapping->writeback_index = done_index;
+ if (!wbc->no_nrwrite_index_update) {
+ if (wbc->range_cyclic || (range_whole && nr_to_write > 0))
+ mapping->writeback_index = done_index;
+ wbc->nr_to_write = nr_to_write;
+ }
return ret;
}