linux-ext4 - [PATCH 2/4] tune2fs: prevent stable_inodes feature from being cleared

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Message-Id: <20200401203239.163679-3-ebiggers@kernel.org>
Date:   Wed,  1 Apr 2020 13:32:37 -0700
From:   Eric Biggers <ebiggers@...nel.org>
To:     linux-ext4@...r.kernel.org
Cc:     linux-fscrypt@...r.kernel.org
Subject: [PATCH 2/4] tune2fs: prevent stable_inodes feature from being cleared

From: Eric Biggers <ebiggers@...gle.com>

Similar to encrypt and verity, once the stable_inodes feature has been
enabled there may be files anywhere on the filesystem that require this
feature.  Therefore, in general it's unsafe to allow clearing it.  Don't
allow tune2fs to do so.  Like encrypt and verity, it can still be
cleared with debugfs if someone really knows what they're doing.

Signed-off-by: Eric Biggers <ebiggers@...gle.com>
---
 misc/tune2fs.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/misc/tune2fs.c b/misc/tune2fs.c
index ca06c98b..81f90cbf 100644
--- a/misc/tune2fs.c
+++ b/misc/tune2fs.c
@@ -181,8 +181,7 @@ static __u32 clear_ok_features[3] = {
 	EXT3_FEATURE_COMPAT_HAS_JOURNAL |
 		EXT2_FEATURE_COMPAT_RESIZE_INODE |
 		EXT2_FEATURE_COMPAT_DIR_INDEX |
-		EXT4_FEATURE_COMPAT_FAST_COMMIT |
-		EXT4_FEATURE_COMPAT_STABLE_INODES,
+		EXT4_FEATURE_COMPAT_FAST_COMMIT,
 	/* Incompat */
 	EXT2_FEATURE_INCOMPAT_FILETYPE |
 		EXT4_FEATURE_INCOMPAT_FLEX_BG |
-- 
2.26.0.rc2.310.g2932bb562d-goog