ext4 crypto: migrate into vfs's crypto engine

This patch removes the most parts of internal crypto codes.
And then, it modifies and adds some ext4-specific crypt codes to use the generic
facility.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

1 files changed, 15 insertions, 20 deletions

diff --git a/fs/ext4/symlink.c b/fs/ext4/symlink.c
index 75ed5c2f0c16..4d83d9e05f2e 100644
--- a/fs/ext4/symlink.c
+++ b/fs/ext4/symlink.c
@@ -22,23 +22,22 @@
 #include "ext4.h"
 #include "xattr.h"
 
-#ifdef CONFIG_EXT4_FS_ENCRYPTION
 static const char *ext4_encrypted_get_link(struct dentry *dentry,
 					   struct inode *inode,
 					   struct delayed_call *done)
 {
 	struct page *cpage = NULL;
 	char *caddr, *paddr = NULL;
-	struct ext4_str cstr, pstr;
-	struct ext4_encrypted_symlink_data *sd;
+	struct fscrypt_str cstr, pstr;
+	struct fscrypt_symlink_data *sd;
 	loff_t size = min_t(loff_t, i_size_read(inode), PAGE_SIZE - 1);
 	int res;
-	u32 plen, max_size = inode->i_sb->s_blocksize;
+	u32 max_size = inode->i_sb->s_blocksize;
 
 	if (!dentry)
 		return ERR_PTR(-ECHILD);
 
-	res = ext4_get_encryption_info(inode);
+	res = fscrypt_get_encryption_info(inode);
 	if (res)
 		return ERR_PTR(res);
 
@@ -54,30 +53,27 @@ static const char *ext4_encrypted_get_link(struct dentry *dentry,
 	}
 
 	/* Symlink is encrypted */
-	sd = (struct ext4_encrypted_symlink_data *)caddr;
+	sd = (struct fscrypt_symlink_data *)caddr;
 	cstr.name = sd->encrypted_path;
 	cstr.len  = le16_to_cpu(sd->len);
-	if ((cstr.len +
-	     sizeof(struct ext4_encrypted_symlink_data) - 1) >
-	    max_size) {
+	if ((cstr.len + sizeof(struct fscrypt_symlink_data) - 1) > max_size) {
 		/* Symlink data on the disk is corrupted */
 		res = -EFSCORRUPTED;
 		goto errout;
 	}
-	plen = (cstr.len < EXT4_FNAME_CRYPTO_DIGEST_SIZE*2) ?
-		EXT4_FNAME_CRYPTO_DIGEST_SIZE*2 : cstr.len;
-	paddr = kmalloc(plen + 1, GFP_NOFS);
-	if (!paddr) {
-		res = -ENOMEM;
+
+	res = fscrypt_fname_alloc_buffer(inode, cstr.len, &pstr);
+	if (res)
 		goto errout;
-	}
-	pstr.name = paddr;
-	pstr.len = plen;
-	res = _ext4_fname_disk_to_usr(inode, NULL, &cstr, &pstr);
+
+	res = fscrypt_fname_disk_to_usr(inode, 0, 0, &cstr, &pstr);
 	if (res < 0)
 		goto errout;
+
+	paddr = pstr.name;
+
 	/* Null-terminate the name */
-	if (res <= plen)
+	if (res <= pstr.len)
 		paddr[res] = '\0';
 	if (cpage)
 		put_page(cpage);
@@ -99,7 +95,6 @@ const struct inode_operations ext4_encrypted_symlink_inode_operations = {
 	.listxattr	= ext4_listxattr,
 	.removexattr	= generic_removexattr,
 };
-#endif
 
 const struct inode_operations ext4_symlink_inode_operations = {
 	.readlink	= generic_readlink,