ecryptfs: clean up page flag handling

The functions that eventually call down to ecryptfs_read_lower(),
ecryptfs_decrypt_page(), and ecryptfs_copy_up_encrypted_with_header()
should have the responsibility of managing the page Uptodate
status. This patch gets rid of some of the ugliness that resulted from
trying to push some of the page flag setting too far down the stack.

Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 21 insertions, 7 deletions

diff --git a/fs/ecryptfs/mmap.c b/fs/ecryptfs/mmap.c
index 4eb09c1753c6..16a7a555f392 100644
--- a/fs/ecryptfs/mmap.c
+++ b/fs/ecryptfs/mmap.c
@@ -37,23 +37,27 @@
 struct kmem_cache *ecryptfs_lower_page_cache;
 
 /**
- * ecryptfs_get1page
+ * ecryptfs_get_locked_page
  *
  * Get one page from cache or lower f/s, return error otherwise.
  *
- * Returns unlocked and up-to-date page (if ok), with increased
+ * Returns locked and up-to-date page (if ok), with increased
  * refcnt.
  */
-struct page *ecryptfs_get1page(struct file *file, loff_t index)
+struct page *ecryptfs_get_locked_page(struct file *file, loff_t index)
 {
 	struct dentry *dentry;
 	struct inode *inode;
 	struct address_space *mapping;
+	struct page *page;
 
 	dentry = file->f_path.dentry;
 	inode = dentry->d_inode;
 	mapping = inode->i_mapping;
-	return read_mapping_page(mapping, index, (void *)file);
+	page = read_mapping_page(mapping, index, (void *)file);
+	if (!IS_ERR(page))
+		lock_page(page);
+	return page;
 }
 
 /**
@@ -146,12 +150,10 @@ ecryptfs_copy_up_encrypted_with_header(struct page *page,
 			kunmap_atomic(page_virt, KM_USER0);
 			flush_dcache_page(page);
 			if (rc) {
-				ClearPageUptodate(page);
 				printk(KERN_ERR "%s: Error reading xattr "
 				       "region; rc = [%d]\n", __FUNCTION__, rc);
 				goto out;
 			}
-			SetPageUptodate(page);
 		} else {
 			/* This is an encrypted data extent */
 			loff_t lower_offset =
@@ -232,6 +234,10 @@ static int ecryptfs_readpage(struct file *file, struct page *page)
 		}
 	}
 out:
+	if (rc)
+		ClearPageUptodate(page);
+	else
+		SetPageUptodate(page);
 	ecryptfs_printk(KERN_DEBUG, "Unlocking page with index = [0x%.16x]\n",
 			page->index);
 	unlock_page(page);
@@ -265,10 +271,18 @@ static int ecryptfs_prepare_write(struct file *file, struct page *page,
 	if (from == 0 && to == PAGE_CACHE_SIZE)
 		goto out;	/* If we are writing a full page, it will be
 				   up to date. */
-	if (!PageUptodate(page))
+	if (!PageUptodate(page)) {
 		rc = ecryptfs_read_lower_page_segment(page, page->index, 0,
 						      PAGE_CACHE_SIZE,
 						      page->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) {
 		loff_t end_of_prev_pg_pos =
 			(((loff_t)page->index << PAGE_CACHE_SHIFT) - 1);