mm: fix dirty_bytes/dirty_background_bytes sysctls on 64bit arches

[sfrench/cifs-2.6.git] / mm / page-writeback.c

diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index b493db7841dc6c2db77d10eab751f6e1f62e7355..c17005e73974f780143b5ea8e7f353b37b1a75cb 100644 (file)
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -209,7 +209,7 @@ int dirty_bytes_handler(struct ctl_table *table, int write,
                struct file *filp, void __user *buffer, size_t *lenp,
                loff_t *ppos)
 {
-       int old_bytes = vm_dirty_bytes;
+       unsigned long old_bytes = vm_dirty_bytes;
        int ret;
 
        ret = proc_doulongvec_minmax(table, write, filp, buffer, lenp, ppos);
@@ -1051,13 +1051,22 @@ continue_unlock:
                                }
                        }
 
-                       if (wbc->sync_mode == WB_SYNC_NONE) {
-                               wbc->nr_to_write--;
-                               if (wbc->nr_to_write <= 0) {
-                                       done = 1;
-                                       break;
-                               }
+                       if (nr_to_write > 0)
+                               nr_to_write--;
+                       else if (wbc->sync_mode == WB_SYNC_NONE) {
+                               /*
+                                * We stop writing back only if we are not
+                                * doing integrity sync. In case of integrity
+                                * sync we have to keep going because someone
+                                * may be concurrently dirtying pages, and we
+                                * might have synced a lot of newly appeared
+                                * dirty pages, but have not synced all of the
+                                * old dirty pages.
+                                */
+                               done = 1;
+                               break;
                        }
+
                        if (wbc->nonblocking && bdi_write_congested(bdi)) {
                                wbc->encountered_congestion = 1;
                                done = 1;