---

yaml
---
r: 61528
b: refs/heads/master
c: d00806b
h: refs/heads/master
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 589f1e81bde732dd0b1bc5d01b6bddd4bcb4527b
+refs/heads/master: d00806b183152af6d24f46f0c33f14162ca1262a

trunk/fs/gfs2/ops_file.c

@@ -364,6 +364,8 @@ static int gfs2_mmap(struct file *file, struct vm_area_struct *vma)
 	else
 		vma->vm_ops = &gfs2_vm_ops_private;
 
+	vma->vm_flags |= VM_CAN_INVALIDATE;
+
 	gfs2_glock_dq_uninit(&i_gh);
 
 	return error;

trunk/fs/gfs2/ops_vm.c

@@ -138,6 +138,8 @@ static struct page *gfs2_sharewrite_nopage(struct vm_area_struct *area,
 	if (alloc_required) {
 		error = alloc_page_backing(ip, result);
 		if (error) {
+			if (area->vm_flags & VM_CAN_INVALIDATE)
+				unlock_page(result);
 			page_cache_release(result);
 			result = NULL;
 			goto out;

trunk/fs/ncpfs/mmap.c

@@ -123,6 +123,7 @@ int ncp_mmap(struct file *file, struct vm_area_struct *vma)
 		return -EFBIG;
 
 	vma->vm_ops = &ncp_file_mmap;
+	vma->vm_flags |= VM_CAN_INVALIDATE;
 	file_accessed(file);
 	return 0;
 }

trunk/fs/ocfs2/mmap.c

@@ -226,6 +226,7 @@ int ocfs2_mmap(struct file *file, struct vm_area_struct *vma)
 	ocfs2_meta_unlock(file->f_dentry->d_inode, lock_level);
 out:
 	vma->vm_ops = &ocfs2_file_vm_ops;
+	vma->vm_flags |= VM_CAN_INVALIDATE;
 	return 0;
 }
 

trunk/fs/xfs/linux-2.6/xfs_file.c

@@ -310,6 +310,7 @@ xfs_file_mmap(
 	struct vm_area_struct *vma)
 {
 	vma->vm_ops = &xfs_file_vm_ops;
+	vma->vm_flags |= VM_CAN_INVALIDATE;
 
 #ifdef CONFIG_XFS_DMAPI
 	if (vn_from_inode(filp->f_path.dentry->d_inode)->v_vfsp->vfs_flag & VFS_DMI)

trunk/include/linux/mm.h

@@ -168,6 +168,12 @@ extern unsigned int kobjsize(const void *objp);
 #define VM_INSERTPAGE	0x02000000	/* The vma has had "vm_insert_page()" done on it */
 #define VM_ALWAYSDUMP	0x04000000	/* Always include in core dumps */
 
+#define VM_CAN_INVALIDATE 0x08000000	/* The mapping may be invalidated,
+					 * eg. truncate or invalidate_inode_*.
+					 * In this case, do_no_page must
+					 * return with the page locked.
+					 */
+
 #ifndef VM_STACK_DEFAULT_FLAGS		/* arch can override this */
 #define VM_STACK_DEFAULT_FLAGS VM_DATA_DEFAULT_FLAGS
 #endif

trunk/mm/filemap.c

@@ -1325,9 +1325,10 @@ struct page *filemap_nopage(struct vm_area_struct *area,
 	unsigned long size, pgoff;
 	int did_readaround = 0, majmin = VM_FAULT_MINOR;
 
+	BUG_ON(!(area->vm_flags & VM_CAN_INVALIDATE));
+
 	pgoff = ((address-area->vm_start) >> PAGE_CACHE_SHIFT) + area->vm_pgoff;
 
-retry_all:
 	size = (i_size_read(inode) + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
 	if (pgoff >= size)
 		goto outside_data_content;
@@ -1349,7 +1350,7 @@ struct page *filemap_nopage(struct vm_area_struct *area,
 	 * Do we have something in the page cache already?
 	 */
 retry_find:
-	page = find_get_page(mapping, pgoff);
+	page = find_lock_page(mapping, pgoff);
 	if (!page) {
 		unsigned long ra_pages;
 
@@ -1383,7 +1384,7 @@ struct page *filemap_nopage(struct vm_area_struct *area,
 				start = pgoff - ra_pages / 2;
 			do_page_cache_readahead(mapping, file, start, ra_pages);
 		}
-		page = find_get_page(mapping, pgoff);
+		page = find_lock_page(mapping, pgoff);
 		if (!page)
 			goto no_cached_page;
 	}
@@ -1392,13 +1393,19 @@ struct page *filemap_nopage(struct vm_area_struct *area,
 		ra->mmap_hit++;
 
 	/*
-	 * Ok, found a page in the page cache, now we need to check
-	 * that it's up-to-date.
+	 * We have a locked page in the page cache, now we need to check
+	 * that it's up-to-date. If not, it is going to be due to an error.
 	 */
-	if (!PageUptodate(page))
+	if (unlikely(!PageUptodate(page)))
 		goto page_not_uptodate;
 
-success:
+	/* Must recheck i_size under page lock */
+	size = (i_size_read(inode) + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
+	if (unlikely(pgoff >= size)) {
+		unlock_page(page);
+		goto outside_data_content;
+	}
+
 	/*
 	 * Found the page and have a reference on it.
 	 */
@@ -1440,6 +1447,7 @@ struct page *filemap_nopage(struct vm_area_struct *area,
 	return NOPAGE_SIGBUS;
 
 page_not_uptodate:
+	/* IO error path */
 	if (!did_readaround) {
 		majmin = VM_FAULT_MAJOR;
 		count_vm_event(PGMAJFAULT);
@@ -1451,37 +1459,15 @@ struct page *filemap_nopage(struct vm_area_struct *area,
 	 * because there really aren't any performance issues here
 	 * and we need to check for errors.
 	 */
-	lock_page(page);
-
-	/* Somebody truncated the page on us? */
-	if (!page->mapping) {
-		unlock_page(page);
-		page_cache_release(page);
-		goto retry_all;
-	}
-
-	/* Somebody else successfully read it in? */
-	if (PageUptodate(page)) {
-		unlock_page(page);
-		goto success;
-	}
 	ClearPageError(page);
 	error = mapping->a_ops->readpage(file, page);
-	if (!error) {
-		wait_on_page_locked(page);
-		if (PageUptodate(page))
-			goto success;
-	} else if (error == AOP_TRUNCATED_PAGE) {
-		page_cache_release(page);
+	page_cache_release(page);
+
+	if (!error || error == AOP_TRUNCATED_PAGE)
 		goto retry_find;
-	}
 
-	/*
-	 * Things didn't work out. Return zero to tell the
-	 * mm layer so, possibly freeing the page cache page first.
-	 */
+	/* Things didn't work out. Return zero to tell the mm layer so. */
 	shrink_readahead_size_eio(file, ra);
-	page_cache_release(page);
 	return NOPAGE_SIGBUS;
 }
 EXPORT_SYMBOL(filemap_nopage);
@@ -1674,6 +1660,7 @@ int generic_file_mmap(struct file * file, struct vm_area_struct * vma)
 		return -ENOEXEC;
 	file_accessed(file);
 	vma->vm_ops = &generic_file_vm_ops;
+	vma->vm_flags |= VM_CAN_INVALIDATE;
 	return 0;
 }