fscrypt: Cleanup page locking requirements for fscrypt_{decrypt,encrypt}_page()

Rename the FS_CFLG_INPLACE_ENCRYPTION flag to FS_CFLG_OWN_PAGES which,
when set, indicates that the fs uses pages under its own control as
opposed to writeback pages which require locking and a bounce buffer for
encryption.

Signed-off-by: David Gstir <david@sigma-star.at>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

diff --git a/fs/crypto/crypto.c b/fs/crypto/crypto.c
index 8c104e712bb226ca09cb6fd512d31204110f8bcf..5ffc59436397de621de2308700e63a8c2b9c4450 100644 (file)
--- a/fs/crypto/crypto.c
+++ b/fs/crypto/crypto.c
@@ -238,7 +238,7 @@ static struct page *alloc_bounce_page(struct fscrypt_ctx *ctx, gfp_t gfp_flags)
  * fscrypt_restore_control_page() on the returned ciphertext page to
  * release the bounce buffer and the encryption context.
  *
- * In-place encryption is used by setting the FS_CFLG_INPLACE_ENCRYPTION flag in
+ * In-place encryption is used by setting the FS_CFLG_OWN_PAGES flag in
  * fscrypt_operations. Here, the input-page is returned with its content
  * encrypted.
  *
@@ -258,7 +258,7 @@ struct page *fscrypt_encrypt_page(const struct inode *inode,
 
        BUG_ON(len % FS_CRYPTO_BLOCK_SIZE != 0);
 
-       if (inode->i_sb->s_cop->flags & FS_CFLG_INPLACE_ENCRYPTION) {
+       if (inode->i_sb->s_cop->flags & FS_CFLG_OWN_PAGES) {
                /* with inplace-encryption we just encrypt the page */
                err = do_page_crypto(inode, FS_ENCRYPT, lblk_num,
                                        page, ciphertext_page,
@@ -269,6 +269,8 @@ struct page *fscrypt_encrypt_page(const struct inode *inode,
                return ciphertext_page;
        }
 
+       BUG_ON(!PageLocked(page));
+
        ctx = fscrypt_get_ctx(inode, gfp_flags);
        if (IS_ERR(ctx))
                return (struct page *)ctx;
@@ -301,7 +303,7 @@ EXPORT_SYMBOL(fscrypt_encrypt_page);
  * fscrypt_decrypt_page() - Decrypts a page in-place
  * @inode:     The corresponding inode for the page to decrypt.
  * @page:      The page to decrypt. Must be locked in case
- *             it is a writeback page.
+ *             it is a writeback page (FS_CFLG_OWN_PAGES unset).
  * @len:       Number of bytes in @page to be decrypted.
  * @offs:      Start of data in @page.
  * @lblk_num:  Logical block number.
@@ -315,6 +317,9 @@ EXPORT_SYMBOL(fscrypt_encrypt_page);
 int fscrypt_decrypt_page(const struct inode *inode, struct page *page,
                        unsigned int len, unsigned int offs, u64 lblk_num)
 {
+       if (!(inode->i_sb->s_cop->flags & FS_CFLG_OWN_PAGES))
+               BUG_ON(!PageLocked(page));
+
        return do_page_crypto(inode, FS_DECRYPT, lblk_num, page, page, len,
                        offs, GFP_NOFS);
 }

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 1485ac273bfbf85d7cee60ccf818f1782220428a..fb2b514f675b50dd4a055202fcfd833fe96f3dbb 100644 (file)
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -3744,7 +3744,6 @@ 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);
-                       BUG_ON(!PageLocked(page));
                        WARN_ON_ONCE(fscrypt_decrypt_page(page->mapping->host,
                                                page, PAGE_SIZE, 0, page->index));
                }

diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index 435590c4b341b20966771722013c13f5e1a425b9..9f0ba90b92e4aee60622322973ef80d14b24e1e6 100644 (file)
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -1194,7 +1194,6 @@ int do_write_data_page(struct f2fs_io_info *fio)
                f2fs_wait_on_encrypted_page_writeback(F2FS_I_SB(inode),
                                                        fio->old_blkaddr);
 retry_encrypt:
-               BUG_ON(!PageLocked(fio->page));
                fio->encrypted_page = fscrypt_encrypt_page(inode, fio->page,
                                                        PAGE_SIZE, 0,
                                                        fio->page->index,

diff --git a/include/linux/fscrypto.h b/include/linux/fscrypto.h
index 2d9abfa22b948d7be9de0c34c08fc3004cacfac7..188b4fa59cbf19b68445df7a01250cbd2e449cd7 100644 (file)
--- a/include/linux/fscrypto.h
+++ b/include/linux/fscrypto.h
@@ -80,7 +80,7 @@ struct fscrypt_name {
 /*
  * fscrypt superblock flags
  */
-#define FS_CFLG_INPLACE_ENCRYPTION (1U << 1)
+#define FS_CFLG_OWN_PAGES (1U << 1)
 
 /*
  * crypto opertions for filesystems