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| author | David Gstir <david@sigma-star.at> | 2016-11-13 22:20:44 +0100 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2016-11-13 18:47:04 -0500 |
| commit | 1c7dcf69eea3224474fe884a03b3e19b82d1101e (patch) | |
| tree | b2d64ef7305d32d4da2fc45946a980ee85a212cc | |
| parent | bc33b0ca11e3df467777a4fa7639ba488c9d4911 (diff) | |
| download | linux-1c7dcf69eea3224474fe884a03b3e19b82d1101e.tar.bz2 | |
fscrypt: Add in-place encryption mode
ext4 and f2fs require a bounce page when encrypting pages. However, not
all filesystems will need that (eg. UBIFS). This is handled via a
flag on fscrypt_operations where a fs implementation can select in-place
encryption over using a bounce page (which is the default).
Signed-off-by: David Gstir <david@sigma-star.at>
Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
| -rw-r--r-- | fs/crypto/crypto.c | 25 | ||||
| -rw-r--r-- | include/linux/fscrypto.h | 6 |
2 files changed, 21 insertions, 10 deletions
diff --git a/fs/crypto/crypto.c b/fs/crypto/crypto.c index 98f87fe8f186..f38dc8aac2fe 100644 --- a/fs/crypto/crypto.c +++ b/fs/crypto/crypto.c @@ -217,8 +217,9 @@ static struct page *alloc_bounce_page(struct fscrypt_ctx *ctx, gfp_t gfp_flags) * @plaintext_page: The page to encrypt. Must be locked. * @gfp_flags: The gfp flag for memory allocation * - * Allocates a ciphertext page and encrypts plaintext_page into it using the ctx - * encryption context. + * Encrypts plaintext_page using the ctx encryption context. If + * the filesystem supports it, encryption is performed in-place, otherwise a + * new ciphertext_page is allocated and returned. * * Called on the page write path. The caller must call * fscrypt_restore_control_page() on the returned ciphertext page to @@ -231,7 +232,7 @@ struct page *fscrypt_encrypt_page(struct inode *inode, struct page *plaintext_page, gfp_t gfp_flags) { struct fscrypt_ctx *ctx; - struct page *ciphertext_page = NULL; + struct page *ciphertext_page = plaintext_page; int err; BUG_ON(!PageLocked(plaintext_page)); @@ -240,10 +241,12 @@ struct page *fscrypt_encrypt_page(struct inode *inode, if (IS_ERR(ctx)) return (struct page *)ctx; - /* The encryption operation will require a bounce page. */ - ciphertext_page = alloc_bounce_page(ctx, gfp_flags); - if (IS_ERR(ciphertext_page)) - goto errout; + if (!(inode->i_sb->s_cop->flags & FS_CFLG_INPLACE_ENCRYPTION)) { + /* The encryption operation will require a bounce page. */ + ciphertext_page = alloc_bounce_page(ctx, gfp_flags); + if (IS_ERR(ciphertext_page)) + goto errout; + } ctx->w.control_page = plaintext_page; err = do_page_crypto(inode, FS_ENCRYPT, plaintext_page->index, @@ -253,9 +256,11 @@ struct page *fscrypt_encrypt_page(struct inode *inode, ciphertext_page = ERR_PTR(err); goto errout; } - SetPagePrivate(ciphertext_page); - set_page_private(ciphertext_page, (unsigned long)ctx); - lock_page(ciphertext_page); + if (!(inode->i_sb->s_cop->flags & FS_CFLG_INPLACE_ENCRYPTION)) { + SetPagePrivate(ciphertext_page); + set_page_private(ciphertext_page, (unsigned long)ctx); + lock_page(ciphertext_page); + } return ciphertext_page; errout: diff --git a/include/linux/fscrypto.h b/include/linux/fscrypto.h index ff8b11b26f31..5a65b0e3773f 100644 --- a/include/linux/fscrypto.h +++ b/include/linux/fscrypto.h @@ -154,9 +154,15 @@ struct fscrypt_name { #define fname_len(p) ((p)->disk_name.len) /* + * fscrypt superblock flags + */ +#define FS_CFLG_INPLACE_ENCRYPTION (1U << 1) + +/* * crypto opertions for filesystems */ struct fscrypt_operations { + unsigned int flags; int (*get_context)(struct inode *, void *, size_t); int (*key_prefix)(struct inode *, u8 **); int (*prepare_context)(struct inode *); |