X-Git-Url: http://pilppa.org/gitweb/gitweb.cgi?a=blobdiff_plain;f=mm%2Ftruncate.c;h=0f4b6d18ab0ed663360e0fba11f46f23e8c6b5b3;hb=96681355929d47151696c47fbba02b394224db04;hp=4a38dd1a4ce85efffaa8275ccaaf1b42251f0ae9;hpb=5f2a105d5e33a038a717995d2738434f9c25aed2;p=linux-2.6-omap-h63xx.git

diff --git a/mm/truncate.c b/mm/truncate.c
index 4a38dd1a4ce..0f4b6d18ab0 100644
--- a/mm/truncate.c
+++ b/mm/truncate.c
@@ -51,21 +51,32 @@ static inline void truncate_partial_page(struct page *page, unsigned partial)
 		do_invalidatepage(page, partial);
 }
 
+/*
+ * This cancels just the dirty bit on the kernel page itself, it
+ * does NOT actually remove dirty bits on any mmap's that may be
+ * around. It also leaves the page tagged dirty, so any sync
+ * activity will still find it on the dirty lists, and in particular,
+ * clear_page_dirty_for_io() will still look at the dirty bits in
+ * the VM.
+ *
+ * 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"? Tought you could.
+ */
 void cancel_dirty_page(struct page *page, unsigned int account_size)
 {
-	/* If we're cancelling the page, it had better not be mapped any more */
-	if (page_mapped(page)) {
-		static unsigned int warncount;
-
-		WARN_ON(++warncount < 5);
-	}
-		
-	if (TestClearPageDirty(page) && account_size &&
-			mapping_cap_account_dirty(page->mapping)) {
-		dec_zone_page_state(page, NR_FILE_DIRTY);
-		task_io_account_cancelled_write(account_size);
+	if (TestClearPageDirty(page)) {
+		struct address_space *mapping = page->mapping;
+		if (mapping && mapping_cap_account_dirty(mapping)) {
+			dec_zone_page_state(page, NR_FILE_DIRTY);
+			if (account_size)
+				task_io_account_cancelled_write(account_size);
+		}
 	}
 }
+EXPORT_SYMBOL(cancel_dirty_page);
 
 /*
  * If truncate cannot remove the fs-private metadata from the page, the page
@@ -74,7 +85,7 @@ void cancel_dirty_page(struct page *page, unsigned int account_size)
  *
  * We need to bale out if page->mapping is no longer equal to the original
  * mapping.  This happens a) when the VM reclaimed the page while we waited on
- * its lock, b) when a concurrent invalidate_inode_pages got there first and
+ * its lock, b) when a concurrent invalidate_mapping_pages got there first and
  * c) when tmpfs swizzles a page between a tmpfs inode and swapper_space.
  */
 static void
@@ -95,7 +106,7 @@ truncate_complete_page(struct address_space *mapping, struct page *page)
 }
 
 /*
- * This is for invalidate_inode_pages().  That function can be called at
+ * This is for invalidate_mapping_pages().  That function can be called at
  * any time, and is not supposed to throw away dirty pages.  But pages can
  * be marked dirty at any time too, so use remove_mapping which safely
  * discards clean, unused pages.
@@ -299,12 +310,7 @@ unlock:
 	}
 	return ret;
 }
-
-unsigned long invalidate_inode_pages(struct address_space *mapping)
-{
-	return invalidate_mapping_pages(mapping, 0, ~0UL);
-}
-EXPORT_SYMBOL(invalidate_inode_pages);
+EXPORT_SYMBOL(invalidate_mapping_pages);
 
 /*
  * This is like invalidate_complete_page(), except it ignores the page's
@@ -337,6 +343,15 @@ failed:
 	return 0;
 }
 
+static int do_launder_page(struct address_space *mapping, struct page *page)
+{
+	if (!PageDirty(page))
+		return 0;
+	if (page->mapping != mapping || mapping->a_ops->launder_page == NULL)
+		return 0;
+	return mapping->a_ops->launder_page(page);
+}
+
 /**
  * invalidate_inode_pages2_range - remove range of pages from an address_space
  * @mapping: the address_space
@@ -360,10 +375,10 @@ int invalidate_inode_pages2_range(struct address_space *mapping,
 
 	pagevec_init(&pvec, 0);
 	next = start;
-	while (next <= end && !ret && !wrapped &&
+	while (next <= end && !wrapped &&
 		pagevec_lookup(&pvec, mapping, next,
 			min(end - next, (pgoff_t)PAGEVEC_SIZE - 1) + 1)) {
-		for (i = 0; !ret && i < pagevec_count(&pvec); i++) {
+		for (i = 0; i < pagevec_count(&pvec); i++) {
 			struct page *page = pvec.pages[i];
 			pgoff_t page_index;
 
@@ -401,14 +416,14 @@ int invalidate_inode_pages2_range(struct address_space *mapping,
 					  PAGE_CACHE_SIZE, 0);
 				}
 			}
-			if (!invalidate_complete_page2(mapping, page))
+			ret = do_launder_page(mapping, page);
+			if (ret == 0 && !invalidate_complete_page2(mapping, page))
 				ret = -EIO;
 			unlock_page(page);
 		}
 		pagevec_release(&pvec);
 		cond_resched();
 	}
-	WARN_ON_ONCE(ret);
 	return ret;
 }
 EXPORT_SYMBOL_GPL(invalidate_inode_pages2_range);