ext4: move ext4 crypto code to its own file crypto.c

This is to cleanup super.c file which has grown quite large.
So, start moving ext4 crypto related code to where it should
be in the first place i.e. fs/ext4/crypto.c

Reviewed-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Ritesh Harjani <ritesh.list@gmail.com>
Link: https://lore.kernel.org/r/7d637e093cbc34d727397e8d41a53a1b9ca7d7a4.1652595565.git.ritesh.list@gmail.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

fs/ext4/Makefile

@@ -17,3 +17,4 @@ ext4-$(CONFIG_EXT4_FS_SECURITY)		+= xattr_security.o
 ext4-inode-test-objs			+= inode-test.o
 obj-$(CONFIG_EXT4_KUNIT_TESTS)		+= ext4-inode-test.o
 ext4-$(CONFIG_FS_VERITY)		+= verity.o
+ext4-$(CONFIG_FS_ENCRYPTION)		+= crypto.o

fs/ext4/crypto.c

@@ -0,0 +1,127 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/quotaops.h>
+
+#include "ext4.h"
+#include "xattr.h"
+#include "ext4_jbd2.h"
+
+static int ext4_get_context(struct inode *inode, void *ctx, size_t len)
+{
+	return ext4_xattr_get(inode, EXT4_XATTR_INDEX_ENCRYPTION,
+				 EXT4_XATTR_NAME_ENCRYPTION_CONTEXT, ctx, len);
+}
+
+static int ext4_set_context(struct inode *inode, const void *ctx, size_t len,
+							void *fs_data)
+{
+	handle_t *handle = fs_data;
+	int res, res2, credits, retries = 0;
+
+	/*
+	 * Encrypting the root directory is not allowed because e2fsck expects
+	 * lost+found to exist and be unencrypted, and encrypting the root
+	 * directory would imply encrypting the lost+found directory as well as
+	 * the filename "lost+found" itself.
+	 */
+	if (inode->i_ino == EXT4_ROOT_INO)
+		return -EPERM;
+
+	if (WARN_ON_ONCE(IS_DAX(inode) && i_size_read(inode)))
+		return -EINVAL;
+
+	if (ext4_test_inode_flag(inode, EXT4_INODE_DAX))
+		return -EOPNOTSUPP;
+
+	res = ext4_convert_inline_data(inode);
+	if (res)
+		return res;
+
+	/*
+	 * If a journal handle was specified, then the encryption context is
+	 * being set on a new inode via inheritance and is part of a larger
+	 * transaction to create the inode.  Otherwise the encryption context is
+	 * being set on an existing inode in its own transaction.  Only in the
+	 * latter case should the "retry on ENOSPC" logic be used.
+	 */
+
+	if (handle) {
+		res = ext4_xattr_set_handle(handle, inode,
+					    EXT4_XATTR_INDEX_ENCRYPTION,
+					    EXT4_XATTR_NAME_ENCRYPTION_CONTEXT,
+					    ctx, len, 0);
+		if (!res) {
+			ext4_set_inode_flag(inode, EXT4_INODE_ENCRYPT);
+			ext4_clear_inode_state(inode,
+					EXT4_STATE_MAY_INLINE_DATA);
+			/*
+			 * Update inode->i_flags - S_ENCRYPTED will be enabled,
+			 * S_DAX may be disabled
+			 */
+			ext4_set_inode_flags(inode, false);
+		}
+		return res;
+	}
+
+	res = dquot_initialize(inode);
+	if (res)
+		return res;
+retry:
+	res = ext4_xattr_set_credits(inode, len, false /* is_create */,
+				     &credits);
+	if (res)
+		return res;
+
+	handle = ext4_journal_start(inode, EXT4_HT_MISC, credits);
+	if (IS_ERR(handle))
+		return PTR_ERR(handle);
+
+	res = ext4_xattr_set_handle(handle, inode, EXT4_XATTR_INDEX_ENCRYPTION,
+				    EXT4_XATTR_NAME_ENCRYPTION_CONTEXT,
+				    ctx, len, 0);
+	if (!res) {
+		ext4_set_inode_flag(inode, EXT4_INODE_ENCRYPT);
+		/*
+		 * Update inode->i_flags - S_ENCRYPTED will be enabled,
+		 * S_DAX may be disabled
+		 */
+		ext4_set_inode_flags(inode, false);
+		res = ext4_mark_inode_dirty(handle, inode);
+		if (res)
+			EXT4_ERROR_INODE(inode, "Failed to mark inode dirty");
+	}
+	res2 = ext4_journal_stop(handle);
+
+	if (res == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
+		goto retry;
+	if (!res)
+		res = res2;
+	return res;
+}
+
+static const union fscrypt_policy *ext4_get_dummy_policy(struct super_block *sb)
+{
+	return EXT4_SB(sb)->s_dummy_enc_policy.policy;
+}
+
+static bool ext4_has_stable_inodes(struct super_block *sb)
+{
+	return ext4_has_feature_stable_inodes(sb);
+}
+
+static void ext4_get_ino_and_lblk_bits(struct super_block *sb,
+				       int *ino_bits_ret, int *lblk_bits_ret)
+{
+	*ino_bits_ret = 8 * sizeof(EXT4_SB(sb)->s_es->s_inodes_count);
+	*lblk_bits_ret = 8 * sizeof(ext4_lblk_t);
+}
+
+const struct fscrypt_operations ext4_cryptops = {
+	.key_prefix		= "ext4:",
+	.get_context		= ext4_get_context,
+	.set_context		= ext4_set_context,
+	.get_dummy_policy	= ext4_get_dummy_policy,
+	.empty_dir		= ext4_empty_dir,
+	.has_stable_inodes	= ext4_has_stable_inodes,
+	.get_ino_and_lblk_bits	= ext4_get_ino_and_lblk_bits,
+};

fs/ext4/ext4.h

@@ -2733,7 +2733,10 @@ extern int ext4_fname_setup_ci_filename(struct inode *dir,
 					 struct ext4_filename *fname);
 #endif
 
+/* ext4 encryption related stuff goes here crypto.c */
 #ifdef CONFIG_FS_ENCRYPTION
+extern const struct fscrypt_operations ext4_cryptops;
+
 static inline void ext4_fname_from_fscrypt_name(struct ext4_filename *dst,
 						const struct fscrypt_name *src)
 {

fs/ext4/super.c

@@ -1495,128 +1495,6 @@ static int ext4_nfs_commit_metadata(struct inode *inode)
 	return ext4_write_inode(inode, &wbc);
 }
 
-#ifdef CONFIG_FS_ENCRYPTION
-static int ext4_get_context(struct inode *inode, void *ctx, size_t len)
-{
-	return ext4_xattr_get(inode, EXT4_XATTR_INDEX_ENCRYPTION,
-				 EXT4_XATTR_NAME_ENCRYPTION_CONTEXT, ctx, len);
-}
-
-static int ext4_set_context(struct inode *inode, const void *ctx, size_t len,
-							void *fs_data)
-{
-	handle_t *handle = fs_data;
-	int res, res2, credits, retries = 0;
-
-	/*
-	 * Encrypting the root directory is not allowed because e2fsck expects
-	 * lost+found to exist and be unencrypted, and encrypting the root
-	 * directory would imply encrypting the lost+found directory as well as
-	 * the filename "lost+found" itself.
-	 */
-	if (inode->i_ino == EXT4_ROOT_INO)
-		return -EPERM;
-
-	if (WARN_ON_ONCE(IS_DAX(inode) && i_size_read(inode)))
-		return -EINVAL;
-
-	if (ext4_test_inode_flag(inode, EXT4_INODE_DAX))
-		return -EOPNOTSUPP;
-
-	res = ext4_convert_inline_data(inode);
-	if (res)
-		return res;
-
-	/*
-	 * If a journal handle was specified, then the encryption context is
-	 * being set on a new inode via inheritance and is part of a larger
-	 * transaction to create the inode.  Otherwise the encryption context is
-	 * being set on an existing inode in its own transaction.  Only in the
-	 * latter case should the "retry on ENOSPC" logic be used.
-	 */
-
-	if (handle) {
-		res = ext4_xattr_set_handle(handle, inode,
-					    EXT4_XATTR_INDEX_ENCRYPTION,
-					    EXT4_XATTR_NAME_ENCRYPTION_CONTEXT,
-					    ctx, len, 0);
-		if (!res) {
-			ext4_set_inode_flag(inode, EXT4_INODE_ENCRYPT);
-			ext4_clear_inode_state(inode,
-					EXT4_STATE_MAY_INLINE_DATA);
-			/*
-			 * Update inode->i_flags - S_ENCRYPTED will be enabled,
-			 * S_DAX may be disabled
-			 */
-			ext4_set_inode_flags(inode, false);
-		}
-		return res;
-	}
-
-	res = dquot_initialize(inode);
-	if (res)
-		return res;
-retry:
-	res = ext4_xattr_set_credits(inode, len, false /* is_create */,
-				     &credits);
-	if (res)
-		return res;
-
-	handle = ext4_journal_start(inode, EXT4_HT_MISC, credits);
-	if (IS_ERR(handle))
-		return PTR_ERR(handle);
-
-	res = ext4_xattr_set_handle(handle, inode, EXT4_XATTR_INDEX_ENCRYPTION,
-				    EXT4_XATTR_NAME_ENCRYPTION_CONTEXT,
-				    ctx, len, 0);
-	if (!res) {
-		ext4_set_inode_flag(inode, EXT4_INODE_ENCRYPT);
-		/*
-		 * Update inode->i_flags - S_ENCRYPTED will be enabled,
-		 * S_DAX may be disabled
-		 */
-		ext4_set_inode_flags(inode, false);
-		res = ext4_mark_inode_dirty(handle, inode);
-		if (res)
-			EXT4_ERROR_INODE(inode, "Failed to mark inode dirty");
-	}
-	res2 = ext4_journal_stop(handle);
-
-	if (res == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
-		goto retry;
-	if (!res)
-		res = res2;
-	return res;
-}
-
-static const union fscrypt_policy *ext4_get_dummy_policy(struct super_block *sb)
-{
-	return EXT4_SB(sb)->s_dummy_enc_policy.policy;
-}
-
-static bool ext4_has_stable_inodes(struct super_block *sb)
-{
-	return ext4_has_feature_stable_inodes(sb);
-}
-
-static void ext4_get_ino_and_lblk_bits(struct super_block *sb,
-				       int *ino_bits_ret, int *lblk_bits_ret)
-{
-	*ino_bits_ret = 8 * sizeof(EXT4_SB(sb)->s_es->s_inodes_count);
-	*lblk_bits_ret = 8 * sizeof(ext4_lblk_t);
-}
-
-static const struct fscrypt_operations ext4_cryptops = {
-	.key_prefix		= "ext4:",
-	.get_context		= ext4_get_context,
-	.set_context		= ext4_set_context,
-	.get_dummy_policy	= ext4_get_dummy_policy,
-	.empty_dir		= ext4_empty_dir,
-	.has_stable_inodes	= ext4_has_stable_inodes,
-	.get_ino_and_lblk_bits	= ext4_get_ino_and_lblk_bits,
-};
-#endif
-
 #ifdef CONFIG_QUOTA
 static const char * const quotatypes[] = INITQFNAMES;
 #define QTYPE2NAME(t) (quotatypes[t])