page_writeback: clean up mess around cancel_dirty_page()

[karo-tx-linux.git] / mm / page-writeback.c

diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 644bcb665773f6e53f50fe6599429595b506f0c5..0372411f38fc516dd64cd6432cce29ee613facf4 100644 (file)
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -2110,6 +2110,25 @@ void account_page_dirtied(struct page *page, struct address_space *mapping)
 }
 EXPORT_SYMBOL(account_page_dirtied);
 
+/*
+ * Helper function for deaccounting dirty page without writeback.
+ *
+ * Doing this should *normally* only ever be done when a page
+ * is truncated, and is not actually mapped anywhere at all. However,
+ * fs/buffer.c does this when it notices that somebody has cleaned
+ * out all the buffers on a page without actually doing it through
+ * the VM. Can you say "ext3 is horribly ugly"? Thought you could.
+ */
+void account_page_cleaned(struct page *page, struct address_space *mapping)
+{
+       if (mapping_cap_account_dirty(mapping)) {
+               dec_zone_page_state(page, NR_FILE_DIRTY);
+               dec_bdi_stat(inode_to_bdi(mapping->host), BDI_RECLAIMABLE);
+               task_io_account_cancelled_write(PAGE_CACHE_SIZE);
+       }
+}
+EXPORT_SYMBOL(account_page_cleaned);
+
 /*
  * For address_spaces which do not use buffers.  Just tag the page as dirty in
  * its radix tree.