diff mbox

[02/29] fscrypt: Allow fscrypt_decrypt_page() to function with non-writeback pages

Message ID 1479072072-6844-3-git-send-email-richard@nod.at
State Changes Requested
Delegated to: Richard Weinberger
Headers show

Commit Message

Richard Weinberger Nov. 13, 2016, 9:20 p.m. UTC 
From: David Gstir <david@sigma-star.at>

Some filesystem might pass pages which do not have page->mapping->host
set to the encrypted inode. We want the caller to explicitly pass the
corresponding inode.

Signed-off-by: David Gstir <david@sigma-star.at>
Signed-off-by: Richard Weinberger <richard@nod.at>
---
 fs/crypto/crypto.c       | 11 ++++++-----
 fs/ext4/inode.c          |  5 +++--
 include/linux/fscrypto.h |  5 +++--
 3 files changed, 12 insertions(+), 9 deletions(-)

Comments

Eric Biggers Nov. 15, 2016, 6:19 p.m. UTC | #1 
On Sun, Nov 13, 2016 at 10:20:45PM +0100, Richard Weinberger wrote:
>  /**
>   * f2crypt_decrypt_page() - Decrypts a page in-place
> - * @page: The page to decrypt. Must be locked.
> + * @inode: The encrypted inode to decrypt.
> + * @page:  The page to decrypt. Must be locked.

Strictly speaking, it's not the inode itself being decrypted, but rather the
data associated with it.  Could this be better expressed as something like
"The inode to which the page belongs"?

Eric
David Gstir Nov. 24, 2016, 5:43 p.m. UTC | #2 
Eric,

> On 15.11.2016, at 19:19, Eric Biggers <ebiggers@google.com> wrote:
> 
> On Sun, Nov 13, 2016 at 10:20:45PM +0100, Richard Weinberger wrote:
>> /**
>>  * f2crypt_decrypt_page() - Decrypts a page in-place
>> - * @page: The page to decrypt. Must be locked.
>> + * @inode: The encrypted inode to decrypt.
>> + * @page:  The page to decrypt. Must be locked.
> 
> Strictly speaking, it's not the inode itself being decrypted, but rather the
> data associated with it.  Could this be better expressed as something like
> "The inode to which the page belongs"?

Yes, you're right. Will address that!

Thanks,
David
diff mbox

Patch

diff --git a/fs/crypto/crypto.c b/fs/crypto/crypto.c
index f38dc8aac2fe..222a70520565 100644
--- a/fs/crypto/crypto.c
+++ b/fs/crypto/crypto.c
@@ -271,7 +271,8 @@  EXPORT_SYMBOL(fscrypt_encrypt_page);
 
 /**
  * f2crypt_decrypt_page() - Decrypts a page in-place
- * @page: The page to decrypt. Must be locked.
+ * @inode: The encrypted inode to decrypt.
+ * @page:  The page to decrypt. Must be locked.
  *
  * Decrypts page in-place using the ctx encryption context.
  *
@@ -279,12 +280,12 @@  EXPORT_SYMBOL(fscrypt_encrypt_page);
  *
  * Return: Zero on success, non-zero otherwise.
  */
-int fscrypt_decrypt_page(struct page *page)
+int fscrypt_decrypt_page(struct inode *inode, struct page *page)
 {
 	BUG_ON(!PageLocked(page));
 
-	return do_page_crypto(page->mapping->host,
-			FS_DECRYPT, page->index, page, page, GFP_NOFS);
+	return do_page_crypto(inode, FS_DECRYPT, page->index, page, page,
+			GFP_NOFS);
 }
 EXPORT_SYMBOL(fscrypt_decrypt_page);
 
@@ -419,7 +420,7 @@  static void completion_pages(struct work_struct *work)
 
 	bio_for_each_segment_all(bv, bio, i) {
 		struct page *page = bv->bv_page;
-		int ret = fscrypt_decrypt_page(page);
+		int ret = fscrypt_decrypt_page(page->mapping->host, page);
 
 		if (ret) {
 			WARN_ON_ONCE(1);
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 9c064727ed62..4b7b842ec024 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -1166,7 +1166,7 @@  static int ext4_block_write_begin(struct page *page, loff_t pos, unsigned len,
 	if (unlikely(err))
 		page_zero_new_buffers(page, from, to);
 	else if (decrypt)
-		err = fscrypt_decrypt_page(page);
+		err = fscrypt_decrypt_page(page->mapping->host, page);
 	return err;
 }
 #endif
@@ -3743,7 +3743,8 @@  static int __ext4_block_zero_page_range(handle_t *handle,
 			/* We expect the key to be set. */
 			BUG_ON(!fscrypt_has_encryption_key(inode));
 			BUG_ON(blocksize != PAGE_SIZE);
-			WARN_ON_ONCE(fscrypt_decrypt_page(page));
+			WARN_ON_ONCE(fscrypt_decrypt_page(page->mapping->host,
+						page));
 		}
 	}
 	if (ext4_should_journal_data(inode)) {
diff --git a/include/linux/fscrypto.h b/include/linux/fscrypto.h
index 5a65b0e3773f..8be8e9657c63 100644
--- a/include/linux/fscrypto.h
+++ b/include/linux/fscrypto.h
@@ -249,7 +249,7 @@  int fscrypt_initialize(void);
 extern struct fscrypt_ctx *fscrypt_get_ctx(struct inode *, gfp_t);
 extern void fscrypt_release_ctx(struct fscrypt_ctx *);
 extern struct page *fscrypt_encrypt_page(struct inode *, struct page *, gfp_t);
-extern int fscrypt_decrypt_page(struct page *);
+extern int fscrypt_decrypt_page(struct inode *, struct page *);
 extern void fscrypt_decrypt_bio_pages(struct fscrypt_ctx *, struct bio *);
 extern void fscrypt_pullback_bio_page(struct page **, bool);
 extern void fscrypt_restore_control_page(struct page *);
@@ -298,7 +298,8 @@  static inline struct page *fscrypt_notsupp_encrypt_page(struct inode *i,
 	return ERR_PTR(-EOPNOTSUPP);
 }
 
-static inline int fscrypt_notsupp_decrypt_page(struct page *p)
+static inline int fscrypt_notsupp_decrypt_page(struct inode *i,
+						struct page *p)
 {
 	return -EOPNOTSUPP;
 }