[PATCHv2 0/3] ext4/crypto: Move out crypto related ops to crypto.c

[PATCHv2 0/3] ext4/crypto: Move out crypto related ops to crypto.c

[Ritesh Harjani]

Hello,

This is 1st in the series to cleanup ext4/super.c, since it has grown quite
large. This moves out crypto related ops and few fs encryption related
definitions to fs/ext4/crypto.c

I have tested "-g encrypt" xfstests group and don't see any surprises there.
The changes are relatively straight forward since it is just moving/refactoring.

Currently these patches apply cleanly on ext4 tree's dev branch.
Since in these series test_dummy_encryption related changes are dropped, hence
I don't think that this should give any major conflict with Eric's series.


NOTE: I noticed we could move both ext4 & f2fs to use uuid_t lib API from
include/linux/uuid.h for managing sb->s_encrypt_pw_salt.
That should kill custom implementations of uuid_is_zero()/uuid_is_nonzero().
But since I noticed it while writing this cover letter, so I would like to
do those changes in a seperate patch series if that is ok. That way maybe we
could cleanup tree wide changes in fs/ (if there are others too).


RFC -> v2
==========
1. Dropped all test_dummy_encryption related changes
   (Eric has separately submitted a v3 for fixing more general problems with
    that mount option).
2. Addressed Eric comments to:-
	1. rename ext4_crypto.c -> crypto.c
	2. Refactor out ext4_ioc_get_encryption_pwsalt() into crypto.c
3. Made ext4_fname_from_fscrypt_name() static since it is only being called
   from within crypto.c functions.

[RFC] - https://lore.kernel.org/linux-ext4/cover.1650517532.git.ritesh.list@gmail.com/

Ritesh Harjani (3):
  ext4: Move ext4 crypto code to its own file crypto.c
  ext4: Cleanup function defs from ext4.h into crypto.c
  ext4: Refactor and move ext4_ioc_get_encryption_pwsalt()

 fs/ext4/Makefile |   1 +
 fs/ext4/crypto.c | 245 +++++++++++++++++++++++++++++++++++++++++++++++
 fs/ext4/ext4.h   |  79 ++++-----------
 fs/ext4/ioctl.c  |  58 +----------
 fs/ext4/super.c  | 122 -----------------------
 5 files changed, 264 insertions(+), 241 deletions(-)
 create mode 100644 fs/ext4/crypto.c

--
2.31.1

[PATCHv2 1/3] ext4: Move ext4 crypto code to its own file crypto.c

[Ritesh Harjani]

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

Signed-off-by: Ritesh Harjani <ritesh.list@gmail.com>
---
 fs/ext4/Makefile |   1 +
 fs/ext4/crypto.c | 127 +++++++++++++++++++++++++++++++++++++++++++++++
 fs/ext4/ext4.h   |   3 ++
 fs/ext4/super.c  | 122 ---------------------------------------------
 4 files changed, 131 insertions(+), 122 deletions(-)
 create mode 100644 fs/ext4/crypto.c

diff --git a/fs/ext4/Makefile b/fs/ext4/Makefile
index 7d89142e1421..72206a292676 100644
--- a/fs/ext4/Makefile
+++ b/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
diff --git a/fs/ext4/crypto.c b/fs/ext4/crypto.c
new file mode 100644
index 000000000000..e5413c0970ee
--- /dev/null
+++ b/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,
+};
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index a743b1e3b89e..9100f0ba4a52 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -2731,6 +2731,9 @@ extern int ext4_fname_setup_ci_filename(struct inode *dir,
 					 struct ext4_filename *fname);
 #endif
 
+/* ext4 encryption related stuff goes here crypto.c */
+extern const struct fscrypt_operations ext4_cryptops;
+
 #ifdef CONFIG_FS_ENCRYPTION
 static inline void ext4_fname_from_fscrypt_name(struct ext4_filename *dst,
 						const struct fscrypt_name *src)
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 1847b46af808..e6cfd338712c 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -1492,128 +1492,6 @@ 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])
-- 
2.31.1

[PATCHv2 2/3] ext4: Cleanup function defs from ext4.h into crypto.c

[Ritesh Harjani]

Some of these functions when CONFIG_FS_ENCRYPTION is enabled are not
really inline (let compiler be the best judge of it).
Remove inline and move them into crypto.c where they should be present.

Signed-off-by: Ritesh Harjani <ritesh.list@gmail.com>
---
 fs/ext4/crypto.c | 65 ++++++++++++++++++++++++++++++++++++++++++++
 fs/ext4/ext4.h   | 70 +++++-------------------------------------------
 2 files changed, 71 insertions(+), 64 deletions(-)

diff --git a/fs/ext4/crypto.c b/fs/ext4/crypto.c
index e5413c0970ee..f8333927f0f6 100644
--- a/fs/ext4/crypto.c
+++ b/fs/ext4/crypto.c
@@ -6,6 +6,71 @@
 #include "xattr.h"
 #include "ext4_jbd2.h"
 
+static void ext4_fname_from_fscrypt_name(struct ext4_filename *dst,
+					 const struct fscrypt_name *src)
+{
+	memset(dst, 0, sizeof(*dst));
+
+	dst->usr_fname = src->usr_fname;
+	dst->disk_name = src->disk_name;
+	dst->hinfo.hash = src->hash;
+	dst->hinfo.minor_hash = src->minor_hash;
+	dst->crypto_buf = src->crypto_buf;
+}
+
+int ext4_fname_setup_filename(struct inode *dir, const struct qstr *iname,
+			      int lookup, struct ext4_filename *fname)
+{
+	struct fscrypt_name name;
+	int err;
+
+	err = fscrypt_setup_filename(dir, iname, lookup, &name);
+	if (err)
+		return err;
+
+	ext4_fname_from_fscrypt_name(fname, &name);
+
+#if IS_ENABLED(CONFIG_UNICODE)
+	err = ext4_fname_setup_ci_filename(dir, iname, fname);
+#endif
+	return err;
+}
+
+int ext4_fname_prepare_lookup(struct inode *dir, struct dentry *dentry,
+			      struct ext4_filename *fname)
+{
+	struct fscrypt_name name;
+	int err;
+
+	err = fscrypt_prepare_lookup(dir, dentry, &name);
+	if (err)
+		return err;
+
+	ext4_fname_from_fscrypt_name(fname, &name);
+
+#if IS_ENABLED(CONFIG_UNICODE)
+	err = ext4_fname_setup_ci_filename(dir, &dentry->d_name, fname);
+#endif
+	return err;
+}
+
+void ext4_fname_free_filename(struct ext4_filename *fname)
+{
+	struct fscrypt_name name;
+
+	name.crypto_buf = fname->crypto_buf;
+	fscrypt_free_filename(&name);
+
+	fname->crypto_buf.name = NULL;
+	fname->usr_fname = NULL;
+	fname->disk_name.name = NULL;
+
+#if IS_ENABLED(CONFIG_UNICODE)
+	kfree(fname->cf_name.name);
+	fname->cf_name.name = NULL;
+#endif
+}
+
 static int ext4_get_context(struct inode *inode, void *ctx, size_t len)
 {
 	return ext4_xattr_get(inode, EXT4_XATTR_INDEX_ENCRYPTION,
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 9100f0ba4a52..11bb0d2ee2eb 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -2735,73 +2735,15 @@ extern int ext4_fname_setup_ci_filename(struct inode *dir,
 extern const struct fscrypt_operations ext4_cryptops;
 
 #ifdef CONFIG_FS_ENCRYPTION
-static inline void ext4_fname_from_fscrypt_name(struct ext4_filename *dst,
-						const struct fscrypt_name *src)
-{
-	memset(dst, 0, sizeof(*dst));
-
-	dst->usr_fname = src->usr_fname;
-	dst->disk_name = src->disk_name;
-	dst->hinfo.hash = src->hash;
-	dst->hinfo.minor_hash = src->minor_hash;
-	dst->crypto_buf = src->crypto_buf;
-}
-
-static inline int ext4_fname_setup_filename(struct inode *dir,
-					    const struct qstr *iname,
-					    int lookup,
-					    struct ext4_filename *fname)
-{
-	struct fscrypt_name name;
-	int err;
+int ext4_fname_setup_filename(struct inode *dir,
+			      const struct qstr *iname, int lookup,
+			      struct ext4_filename *fname);
 
-	err = fscrypt_setup_filename(dir, iname, lookup, &name);
-	if (err)
-		return err;
+int ext4_fname_prepare_lookup(struct inode *dir, struct dentry *dentry,
+			      struct ext4_filename *fname);
 
-	ext4_fname_from_fscrypt_name(fname, &name);
+void ext4_fname_free_filename(struct ext4_filename *fname);
 
-#if IS_ENABLED(CONFIG_UNICODE)
-	err = ext4_fname_setup_ci_filename(dir, iname, fname);
-#endif
-	return err;
-}
-
-static inline int ext4_fname_prepare_lookup(struct inode *dir,
-					    struct dentry *dentry,
-					    struct ext4_filename *fname)
-{
-	struct fscrypt_name name;
-	int err;
-
-	err = fscrypt_prepare_lookup(dir, dentry, &name);
-	if (err)
-		return err;
-
-	ext4_fname_from_fscrypt_name(fname, &name);
-
-#if IS_ENABLED(CONFIG_UNICODE)
-	err = ext4_fname_setup_ci_filename(dir, &dentry->d_name, fname);
-#endif
-	return err;
-}
-
-static inline void ext4_fname_free_filename(struct ext4_filename *fname)
-{
-	struct fscrypt_name name;
-
-	name.crypto_buf = fname->crypto_buf;
-	fscrypt_free_filename(&name);
-
-	fname->crypto_buf.name = NULL;
-	fname->usr_fname = NULL;
-	fname->disk_name.name = NULL;
-
-#if IS_ENABLED(CONFIG_UNICODE)
-	kfree(fname->cf_name.name);
-	fname->cf_name.name = NULL;
-#endif
-}
 #else /* !CONFIG_FS_ENCRYPTION */
 static inline int ext4_fname_setup_filename(struct inode *dir,
 					    const struct qstr *iname,
-- 
2.31.1

[PATCHv2 3/3] ext4: Refactor and move ext4_ioc_get_encryption_pwsalt()

[Ritesh Harjani]

This patch move code for FS_IOC_GET_ENCRYPTION_PWSALT case into
ext4's crypto.c file, i.e. ext4_ioc_get_encryption_pwsalt()
and uuid_is_zero(). This is mostly refactoring logic and should
not affect any functionality change.

Suggested-by: Eric Biggers <ebiggers@kernel.org>
Signed-off-by: Ritesh Harjani <ritesh.list@gmail.com>
---
 fs/ext4/crypto.c | 53 +++++++++++++++++++++++++++++++++++++++++++
 fs/ext4/ext4.h   |  8 +++++++
 fs/ext4/ioctl.c  | 58 ++----------------------------------------------
 3 files changed, 63 insertions(+), 56 deletions(-)

diff --git a/fs/ext4/crypto.c b/fs/ext4/crypto.c
index f8333927f0f6..36bcfeecdb00 100644
--- a/fs/ext4/crypto.c
+++ b/fs/ext4/crypto.c
@@ -71,6 +71,59 @@ void ext4_fname_free_filename(struct ext4_filename *fname)
 #endif
 }
 
+static bool uuid_is_zero(__u8 u[16])
+{
+	int i;
+
+	for (i = 0; i < 16; i++)
+		if (u[i])
+			return false;
+	return true;
+}
+
+int ext4_ioc_get_encryption_pwsalt(struct file *filp, void __user *arg)
+{
+	struct super_block *sb = file_inode(filp)->i_sb;
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	int err, err2;
+	handle_t *handle;
+
+	if (!ext4_has_feature_encrypt(sb))
+		return -EOPNOTSUPP;
+
+	if (uuid_is_zero(sbi->s_es->s_encrypt_pw_salt)) {
+		err = mnt_want_write_file(filp);
+		if (err)
+			return err;
+		handle = ext4_journal_start_sb(sb, EXT4_HT_MISC, 1);
+		if (IS_ERR(handle)) {
+			err = PTR_ERR(handle);
+			goto pwsalt_err_exit;
+		}
+		err = ext4_journal_get_write_access(handle, sb, sbi->s_sbh,
+						    EXT4_JTR_NONE);
+		if (err)
+			goto pwsalt_err_journal;
+		lock_buffer(sbi->s_sbh);
+		generate_random_uuid(sbi->s_es->s_encrypt_pw_salt);
+		ext4_superblock_csum_set(sb);
+		unlock_buffer(sbi->s_sbh);
+		err = ext4_handle_dirty_metadata(handle, NULL, sbi->s_sbh);
+pwsalt_err_journal:
+		err2 = ext4_journal_stop(handle);
+		if (err2 && !err)
+			err = err2;
+pwsalt_err_exit:
+		mnt_drop_write_file(filp);
+		if (err)
+			return err;
+	}
+
+	if (copy_to_user(arg, sbi->s_es->s_encrypt_pw_salt, 16))
+		return -EFAULT;
+	return 0;
+}
+
 static int ext4_get_context(struct inode *inode, void *ctx, size_t len)
 {
 	return ext4_xattr_get(inode, EXT4_XATTR_INDEX_ENCRYPTION,
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 11bb0d2ee2eb..b61115fe7ffb 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -2744,6 +2744,8 @@ int ext4_fname_prepare_lookup(struct inode *dir, struct dentry *dentry,
 
 void ext4_fname_free_filename(struct ext4_filename *fname);
 
+int ext4_ioc_get_encryption_pwsalt(struct file *filp, void __user *arg);
+
 #else /* !CONFIG_FS_ENCRYPTION */
 static inline int ext4_fname_setup_filename(struct inode *dir,
 					    const struct qstr *iname,
@@ -2776,6 +2778,12 @@ static inline void ext4_fname_free_filename(struct ext4_filename *fname)
 	fname->cf_name.name = NULL;
 #endif
 }
+
+static inline int ext4_ioc_get_encryption_pwsalt(struct file *filp,
+						 void __user *arg)
+{
+	return -EOPNOTSUPP;
+}
 #endif /* !CONFIG_FS_ENCRYPTION */
 
 /* dir.c */
diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c
index ba44fa1be70a..044e65d44054 100644
--- a/fs/ext4/ioctl.c
+++ b/fs/ext4/ioctl.c
@@ -504,18 +504,6 @@ static long swap_inode_boot_loader(struct super_block *sb,
 	return err;
 }
 
-#ifdef CONFIG_FS_ENCRYPTION
-static int uuid_is_zero(__u8 u[16])
-{
-	int	i;
-
-	for (i = 0; i < 16; i++)
-		if (u[i])
-			return 0;
-	return 1;
-}
-#endif
-
 /*
  * If immutable is set and we are not clearing it, we're not allowed to change
  * anything else in the inode.  Don't error out if we're only trying to set
@@ -1432,51 +1420,9 @@ static long __ext4_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 			return -EOPNOTSUPP;
 		return fscrypt_ioctl_set_policy(filp, (const void __user *)arg);
 
-	case FS_IOC_GET_ENCRYPTION_PWSALT: {
-#ifdef CONFIG_FS_ENCRYPTION
-		int err, err2;
-		struct ext4_sb_info *sbi = EXT4_SB(sb);
-		handle_t *handle;
+	case FS_IOC_GET_ENCRYPTION_PWSALT:
+		return ext4_ioc_get_encryption_pwsalt(filp, (void __user *)arg);
 
-		if (!ext4_has_feature_encrypt(sb))
-			return -EOPNOTSUPP;
-		if (uuid_is_zero(sbi->s_es->s_encrypt_pw_salt)) {
-			err = mnt_want_write_file(filp);
-			if (err)
-				return err;
-			handle = ext4_journal_start_sb(sb, EXT4_HT_MISC, 1);
-			if (IS_ERR(handle)) {
-				err = PTR_ERR(handle);
-				goto pwsalt_err_exit;
-			}
-			err = ext4_journal_get_write_access(handle, sb,
-							    sbi->s_sbh,
-							    EXT4_JTR_NONE);
-			if (err)
-				goto pwsalt_err_journal;
-			lock_buffer(sbi->s_sbh);
-			generate_random_uuid(sbi->s_es->s_encrypt_pw_salt);
-			ext4_superblock_csum_set(sb);
-			unlock_buffer(sbi->s_sbh);
-			err = ext4_handle_dirty_metadata(handle, NULL,
-							 sbi->s_sbh);
-		pwsalt_err_journal:
-			err2 = ext4_journal_stop(handle);
-			if (err2 && !err)
-				err = err2;
-		pwsalt_err_exit:
-			mnt_drop_write_file(filp);
-			if (err)
-				return err;
-		}
-		if (copy_to_user((void __user *) arg,
-				 sbi->s_es->s_encrypt_pw_salt, 16))
-			return -EFAULT;
-		return 0;
-#else
-		return -EOPNOTSUPP;
-#endif
-	}
 	case FS_IOC_GET_ENCRYPTION_POLICY:
 		if (!ext4_has_feature_encrypt(sb))
 			return -EOPNOTSUPP;
-- 
2.31.1

Re: [PATCHv2 1/3] ext4: Move ext4 crypto code to its own file crypto.c

[Eric Biggers]

On Sat, May 14, 2022 at 10:52:46PM +0530, Ritesh Harjani wrote:
> diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
> index a743b1e3b89e..9100f0ba4a52 100644
> --- a/fs/ext4/ext4.h
> +++ b/fs/ext4/ext4.h
> @@ -2731,6 +2731,9 @@ extern int ext4_fname_setup_ci_filename(struct inode *dir,
>  					 struct ext4_filename *fname);
>  #endif
>  
> +/* ext4 encryption related stuff goes here crypto.c */
> +extern const struct fscrypt_operations ext4_cryptops;
> +
>  #ifdef CONFIG_FS_ENCRYPTION

Shouldn't the declaration of ext4_cryptops go in the CONFIG_FS_ENCRYPTION block?

Otherwise this patch looks good, thanks.

Reviewed-by: Eric Biggers <ebiggers@google.com>

- Eric

Re: [PATCHv2 2/3] ext4: Cleanup function defs from ext4.h into crypto.c

[Eric Biggers]

On Sat, May 14, 2022 at 10:52:47PM +0530, Ritesh Harjani wrote:
> diff --git a/fs/ext4/crypto.c b/fs/ext4/crypto.c
[...]
> +int ext4_fname_setup_filename(struct inode *dir, const struct qstr *iname,
> +			      int lookup, struct ext4_filename *fname)
> +{
[...]
> diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
[...]
> +int ext4_fname_setup_filename(struct inode *dir,
> +			      const struct qstr *iname, int lookup,
> +			      struct ext4_filename *fname);

Very minor nit: the above declaration can be formatted on 2 lines, the same as
the definition.

Otherwise this patch looks fine.  I think that filename handling in ext4 in
general is still greatly in need of some cleanups, considering that ext4 now has
to support all combinations of encryption and casefolding.  f2fs does it in a
somewhat cleaner way, IMO.  And it's possible that would lead us down a slightly
different path.  But this is an improvement for now.

Reviewed-by: Eric Biggers <ebiggers@google.com>

- Eric

Re: [PATCHv2 3/3] ext4: Refactor and move ext4_ioc_get_encryption_pwsalt()

[Eric Biggers]

On Sat, May 14, 2022 at 10:52:48PM +0530, Ritesh Harjani wrote:
> diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c

The include <linux/uuid.h> can be removed from this file.

> diff --git a/fs/ext4/crypto.c b/fs/ext4/crypto.c
[...]
> +int ext4_ioc_get_encryption_pwsalt(struct file *filp, void __user *arg)

ext4 has more functions named "ext4_ioctl_*" thtan "ext4_ioc_*", so it might be
worth adding those extra 2 letters for consistency.

Other than the above minor nits this looks good, thanks!

Reviewed-by: Eric Biggers <ebiggers@google.com>

- Eric

Re: [PATCHv2 1/3] ext4: Move ext4 crypto code to its own file crypto.c

[Ritesh Harjani]

On 22/05/14 08:33PM, Eric Biggers wrote:
> On Sat, May 14, 2022 at 10:52:46PM +0530, Ritesh Harjani wrote:
> > diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
> > index a743b1e3b89e..9100f0ba4a52 100644
> > --- a/fs/ext4/ext4.h
> > +++ b/fs/ext4/ext4.h
> > @@ -2731,6 +2731,9 @@ extern int ext4_fname_setup_ci_filename(struct inode *dir,
> >  					 struct ext4_filename *fname);
> >  #endif
> >
> > +/* ext4 encryption related stuff goes here crypto.c */
> > +extern const struct fscrypt_operations ext4_cryptops;
> > +
> >  #ifdef CONFIG_FS_ENCRYPTION
>
> Shouldn't the declaration of ext4_cryptops go in the CONFIG_FS_ENCRYPTION block?

Sure yes. I should move that within CONFIG_FS_ENCRYPTION block.

>
> Otherwise this patch looks good, thanks.
>
> Reviewed-by: Eric Biggers <ebiggers@google.com>

Thanks for the review.

-ritesh

Re: [PATCHv2 2/3] ext4: Cleanup function defs from ext4.h into crypto.c

[Ritesh Harjani]

On 22/05/14 08:40PM, Eric Biggers wrote:
> On Sat, May 14, 2022 at 10:52:47PM +0530, Ritesh Harjani wrote:
> > diff --git a/fs/ext4/crypto.c b/fs/ext4/crypto.c
> [...]
> > +int ext4_fname_setup_filename(struct inode *dir, const struct qstr *iname,
> > +			      int lookup, struct ext4_filename *fname)
> > +{
> [...]
> > diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
> [...]
> > +int ext4_fname_setup_filename(struct inode *dir,
> > +			      const struct qstr *iname, int lookup,
> > +			      struct ext4_filename *fname);
>
> Very minor nit: the above declaration can be formatted on 2 lines, the same as
> the definition.

Thanks for spotting. I will make the change.

>
> Otherwise this patch looks fine.  I think that filename handling in ext4 in
> general is still greatly in need of some cleanups, considering that ext4 now has
> to support all combinations of encryption and casefolding.  f2fs does it in a
> somewhat cleaner way, IMO.  And it's possible that would lead us down a slightly
> different path.  But this is an improvement for now.

Some examples please which you posibly have in mind which should help in
cleanup ext4's filename handling code. I can get back to it after completing
some other items in my todo list.

>
> Reviewed-by: Eric Biggers <ebiggers@google.com>

Thanks!!

-ritesh

Re: [PATCHv2 3/3] ext4: Refactor and move ext4_ioc_get_encryption_pwsalt()

[Ritesh Harjani]

On 22/05/14 08:42PM, Eric Biggers wrote:
> On Sat, May 14, 2022 at 10:52:48PM +0530, Ritesh Harjani wrote:
> > diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c
>
> The include <linux/uuid.h> can be removed from this file.

Yes. I will remove this from ioctl.c and will add it to crypto.c
for generate_random_uuid() definition.

>
> > diff --git a/fs/ext4/crypto.c b/fs/ext4/crypto.c
> [...]
> > +int ext4_ioc_get_encryption_pwsalt(struct file *filp, void __user *arg)
>
> ext4 has more functions named "ext4_ioctl_*" thtan "ext4_ioc_*", so it might be
> worth adding those extra 2 letters for consistency.

You are right.

>
> Other than the above minor nits this looks good, thanks!
>
> Reviewed-by: Eric Biggers <ebiggers@google.com>

Thanks for a thorough review.

I will make these changes and send out a v3 soon.

-ritesh