[rfc][patch 1/5] ecryptfs new aops

[Nick Piggin <npiggin@suse.de>]

Convert ecryptfs to new aops.

Signed-off-by: Nick Piggin <npiggin@suse.de>
---
Index: linux-2.6/fs/ecryptfs/mmap.c
===================================================================
--- linux-2.6.orig/fs/ecryptfs/mmap.c
+++ linux-2.6/fs/ecryptfs/mmap.c
@@ -263,31 +263,38 @@ out:
 	return 0;
 }
 
-static int ecryptfs_prepare_write(struct file *file, struct page *page,
-				  unsigned from, unsigned to)
+static int ecryptfs_write_begin(struct file *file,
+			struct address_space *mapping,
+			loff_t pos, unsigned len, unsigned flags,
+			struct page **pagep, void **fsdata)
 {
+	pgoff_t index = pos >> PAGE_CACHE_SHIFT;
+	struct page *page;
 	int rc = 0;
 
-	if (from == 0 && to == PAGE_CACHE_SIZE)
+	page = __grab_cache_page(mapping, index);
+	if (!page)
+		return -ENOMEM;
+
+	if (flags & AOP_FLAG_UNINTERRUPTIBLE && len == PAGE_CACHE_SIZE)
 		goto out;	/* If we are writing a full page, it will be
 				   up to date. */
 	if (!PageUptodate(page)) {
-		rc = ecryptfs_read_lower_page_segment(page, page->index, 0,
+		rc = ecryptfs_read_lower_page_segment(page, index, 0,
 						      PAGE_CACHE_SIZE,
-						      page->mapping->host);
+						      mapping->host);
 		if (rc) {
 			printk(KERN_ERR "%s: Error attemping to read lower "
 			       "page segment; rc = [%d]\n", __FUNCTION__, rc);
-			ClearPageUptodate(page);
 			goto out;
 		} else
 			SetPageUptodate(page);
 	}
-	if (page->index != 0) {
+	if (index != 0) {
 		loff_t end_of_prev_pg_pos =
-			(((loff_t)page->index << PAGE_CACHE_SHIFT) - 1);
+			(((loff_t)index << PAGE_CACHE_SHIFT) - 1);
 
-		if (end_of_prev_pg_pos > i_size_read(page->mapping->host)) {
+		if (end_of_prev_pg_pos > i_size_read(mapping->host)) {
 			rc = ecryptfs_truncate(file->f_path.dentry,
 					       end_of_prev_pg_pos);
 			if (rc) {
@@ -297,7 +304,7 @@ static int ecryptfs_prepare_write(struct
 				goto out;
 			}
 		}
-		if (end_of_prev_pg_pos + 1 > i_size_read(page->mapping->host))
+		if (end_of_prev_pg_pos + 1 > i_size_read(mapping->host))
 			zero_user_page(page, 0, PAGE_CACHE_SIZE, KM_USER0);
 	}
 out:
@@ -391,21 +398,25 @@ int ecryptfs_write_inode_size_to_metadat
 }
 
 /**
- * ecryptfs_commit_write
+ * ecryptfs_write_end
  * @file: The eCryptfs file object
+ * @mapping: The eCryptfs object
+ * @pos, len: Ignored (we rotate the page IV on each write)
  * @page: The eCryptfs page
- * @from: Ignored (we rotate the page IV on each write)
- * @to: Ignored
  *
  * This is where we encrypt the data and pass the encrypted data to
  * the lower filesystem.  In OpenPGP-compatible mode, we operate on
  * entire underlying packets.
  */
-static int ecryptfs_commit_write(struct file *file, struct page *page,
-				 unsigned from, unsigned to)
-{
-	loff_t pos;
-	struct inode *ecryptfs_inode = page->mapping->host;
+static int ecryptfs_write_end(struct file *file,
+			struct address_space *mapping,
+			loff_t pos, unsigned len, unsigned copied,
+			struct page *page, void *fsdata)
+{
+	pgoff_t index = pos >> PAGE_CACHE_SHIFT;
+	unsigned from = pos & (PAGE_CACHE_SIZE - 1);
+	unsigned to = from + copied;
+	struct inode *ecryptfs_inode = mapping->host;
 	struct ecryptfs_crypt_stat *crypt_stat =
 		&ecryptfs_inode_to_private(file->f_path.dentry->d_inode)->crypt_stat;
 	int rc;
@@ -417,25 +428,22 @@ static int ecryptfs_commit_write(struct 
 	} else
 		ecryptfs_printk(KERN_DEBUG, "Not a new file\n");
 	ecryptfs_printk(KERN_DEBUG, "Calling fill_zeros_to_end_of_page"
-			"(page w/ index = [0x%.16x], to = [%d])\n", page->index,
-			to);
+			"(page w/ index = [0x%.16x], to = [%d])\n", index, to);
 	/* Fills in zeros if 'to' goes beyond inode size */
 	rc = fill_zeros_to_end_of_page(page, to);
 	if (rc) {
 		ecryptfs_printk(KERN_WARNING, "Error attempting to fill "
-				"zeros in page with index = [0x%.16x]\n",
-				page->index);
+			"zeros in page with index = [0x%.16x]\n", index);
 		goto out;
 	}
 	rc = ecryptfs_encrypt_page(page);
 	if (rc) {
 		ecryptfs_printk(KERN_WARNING, "Error encrypting page (upper "
-				"index [0x%.16x])\n", page->index);
+				"index [0x%.16x])\n", index);
 		goto out;
 	}
-	pos = (((loff_t)page->index) << PAGE_CACHE_SHIFT) + to;
-	if (pos > i_size_read(ecryptfs_inode)) {
-		i_size_write(ecryptfs_inode, pos);
+	if (pos + copied > i_size_read(ecryptfs_inode)) {
+		i_size_write(ecryptfs_inode, pos + copied);
 		ecryptfs_printk(KERN_DEBUG, "Expanded file size to "
 				"[0x%.16x]\n", i_size_read(ecryptfs_inode));
 	}
@@ -443,7 +451,11 @@ static int ecryptfs_commit_write(struct 
 	if (rc)
 		printk(KERN_ERR "Error writing inode size to metadata; "
 		       "rc = [%d]\n", rc);
+
+	rc = copied;
 out:
+	unlock_page(page);
+	page_cache_release(page);
 	return rc;
 }
 
@@ -464,7 +476,7 @@ static sector_t ecryptfs_bmap(struct add
 struct address_space_operations ecryptfs_aops = {
 	.writepage = ecryptfs_writepage,
 	.readpage = ecryptfs_readpage,
-	.prepare_write = ecryptfs_prepare_write,
-	.commit_write = ecryptfs_commit_write,
+	.write_begin = ecryptfs_write_begin,
+	.write_end = ecryptfs_write_end,
 	.bmap = ecryptfs_bmap,
 };