HWPOISON: Refactor truncate to allow direct truncating of page v2
Nick Piggin [Wed, 16 Sep 2009 09:50:12 +0000 (11:50 +0200)]
Extract out truncate_inode_page() out of the truncate path so that
it can be used by memory-failure.c

[AK: description, headers, fix typos]
v2: Some white space changes from Fengguang Wu

Signed-off-by: Andi Kleen <ak@linux.intel.com>

include/linux/mm.h
mm/truncate.c

index 082b68c..8cbc0aa 100644 (file)
@@ -794,6 +794,8 @@ static inline void unmap_shared_mapping_range(struct address_space *mapping,
 extern int vmtruncate(struct inode * inode, loff_t offset);
 extern int vmtruncate_range(struct inode * inode, loff_t offset, loff_t end);
 
+int truncate_inode_page(struct address_space *mapping, struct page *page);
+
 #ifdef CONFIG_MMU
 extern int handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma,
                        unsigned long address, unsigned int flags);
index ccc3ecf..2519a7c 100644 (file)
@@ -93,11 +93,11 @@ EXPORT_SYMBOL(cancel_dirty_page);
  * 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
+static int
 truncate_complete_page(struct address_space *mapping, struct page *page)
 {
        if (page->mapping != mapping)
-               return;
+               return -EIO;
 
        if (page_has_private(page))
                do_invalidatepage(page, 0);
@@ -108,6 +108,7 @@ truncate_complete_page(struct address_space *mapping, struct page *page)
        remove_from_page_cache(page);
        ClearPageMappedToDisk(page);
        page_cache_release(page);       /* pagecache ref */
+       return 0;
 }
 
 /*
@@ -135,6 +136,16 @@ invalidate_complete_page(struct address_space *mapping, struct page *page)
        return ret;
 }
 
+int truncate_inode_page(struct address_space *mapping, struct page *page)
+{
+       if (page_mapped(page)) {
+               unmap_mapping_range(mapping,
+                                  (loff_t)page->index << PAGE_CACHE_SHIFT,
+                                  PAGE_CACHE_SIZE, 0);
+       }
+       return truncate_complete_page(mapping, page);
+}
+
 /**
  * truncate_inode_pages - truncate range of pages specified by start & end byte offsets
  * @mapping: mapping to truncate
@@ -196,12 +207,7 @@ void truncate_inode_pages_range(struct address_space *mapping,
                                unlock_page(page);
                                continue;
                        }
-                       if (page_mapped(page)) {
-                               unmap_mapping_range(mapping,
-                                 (loff_t)page_index<<PAGE_CACHE_SHIFT,
-                                 PAGE_CACHE_SIZE, 0);
-                       }
-                       truncate_complete_page(mapping, page);
+                       truncate_inode_page(mapping, page);
                        unlock_page(page);
                }
                pagevec_release(&pvec);
@@ -238,15 +244,10 @@ void truncate_inode_pages_range(struct address_space *mapping,
                                break;
                        lock_page(page);
                        wait_on_page_writeback(page);
-                       if (page_mapped(page)) {
-                               unmap_mapping_range(mapping,
-                                 (loff_t)page->index<<PAGE_CACHE_SHIFT,
-                                 PAGE_CACHE_SIZE, 0);
-                       }
+                       truncate_inode_page(mapping, page);
                        if (page->index > next)
                                next = page->index;
                        next++;
-                       truncate_complete_page(mapping, page);
                        unlock_page(page);
                }
                pagevec_release(&pvec);