linux-ext4 - [PATCH V5 6/7] ext4: Enable encryption for subpage-sized blocks

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Message-Id: <20190823132542.13434-7-chandan@linux.ibm.com>
Date:   Fri, 23 Aug 2019 18:55:41 +0530
From:   Chandan Rajendra <chandan@...ux.ibm.com>
To:     linux-fsdevel@...r.kernel.org, linux-ext4@...r.kernel.org,
        linux-fscrypt@...r.kernel.org
Cc:     Chandan Rajendra <chandan@...ux.ibm.com>, tytso@....edu,
        adilger.kernel@...ger.ca, ebiggers@...nel.org, hch@...radead.org,
        chandanrlinux@...il.com
Subject: [PATCH V5 6/7] ext4: Enable encryption for subpage-sized blocks

Now that we have the code to support encryption for subpage-sized
blocks, this commit removes the conditional check in filesystem mount
code.

The commit also changes the support statement in
Documentation/filesystems/fscrypt.rst to reflect the fact that
encryption of filesystems with blocksize less than page size now works.

Signed-off-by: Chandan Rajendra <chandan@...ux.ibm.com>
---
 Documentation/filesystems/fscrypt.rst | 4 ++--
 fs/ext4/super.c                       | 7 -------
 2 files changed, 2 insertions(+), 9 deletions(-)

diff --git a/Documentation/filesystems/fscrypt.rst b/Documentation/filesystems/fscrypt.rst
index 08c23b60e016..c3efe86bf2b2 100644
--- a/Documentation/filesystems/fscrypt.rst
+++ b/Documentation/filesystems/fscrypt.rst
@@ -213,8 +213,8 @@ Contents encryption
 -------------------
 
 For file contents, each filesystem block is encrypted independently.
-Currently, only the case where the filesystem block size is equal to
-the system's page size (usually 4096 bytes) is supported.
+Starting from Linux kernel 5.4, encryption of filesystems with block
+size less than system's page size is supported.
 
 Each block's IV is set to the logical block number within the file as
 a little endian number, except that:
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 5b92054bf8ea..d580e71ad9c7 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -4322,13 +4322,6 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
 		}
 	}
 
-	if ((DUMMY_ENCRYPTION_ENABLED(sbi) || ext4_has_feature_encrypt(sb)) &&
-	    (blocksize != PAGE_SIZE)) {
-		ext4_msg(sb, KERN_ERR,
-			 "Unsupported blocksize for fs encryption");
-		goto failed_mount_wq;
-	}
-
 	if (DUMMY_ENCRYPTION_ENABLED(sbi) && !sb_rdonly(sb) &&
 	    !ext4_has_feature_encrypt(sb)) {
 		ext4_set_feature_encrypt(sb);
-- 
2.19.1