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| author | Theodore Ts'o <tytso@mit.edu> | 2014-02-12 12:16:04 -0500 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2014-02-12 12:16:04 -0500 |
| commit | 23301410972330c0ae9a8afc379ba2005e249cc6 (patch) | |
| tree | 5931e3ca6be2f6d7b98525ce204f908c30a30936 | |
| parent | 30d29b119ef01776e0a301444ab24defe8d8bef3 (diff) | |
| download | linux-23301410972330c0ae9a8afc379ba2005e249cc6.tar.bz2 | |
ext4: don't try to modify s_flags if the the file system is read-only
If an ext4 file system is created by some tool other than mke2fs
(perhaps by someone who has a pathalogical fear of the GPL) that
doesn't set one or the other of the EXT2_FLAGS_{UN}SIGNED_HASH flags,
and that file system is then mounted read-only, don't try to modify
the s_flags field. Otherwise, if dm_verity is in use, the superblock
will change, causing an dm_verity failure.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: stable@vger.kernel.org
| -rw-r--r-- | fs/ext4/super.c | 20 |
1 files changed, 13 insertions, 7 deletions
diff --git a/fs/ext4/super.c b/fs/ext4/super.c index 1f7784de05b6..710fed2377d4 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -3695,16 +3695,22 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent) for (i = 0; i < 4; i++) sbi->s_hash_seed[i] = le32_to_cpu(es->s_hash_seed[i]); sbi->s_def_hash_version = es->s_def_hash_version; - i = le32_to_cpu(es->s_flags); - if (i & EXT2_FLAGS_UNSIGNED_HASH) - sbi->s_hash_unsigned = 3; - else if ((i & EXT2_FLAGS_SIGNED_HASH) == 0) { + if (EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_DIR_INDEX)) { + i = le32_to_cpu(es->s_flags); + if (i & EXT2_FLAGS_UNSIGNED_HASH) + sbi->s_hash_unsigned = 3; + else if ((i & EXT2_FLAGS_SIGNED_HASH) == 0) { #ifdef __CHAR_UNSIGNED__ - es->s_flags |= cpu_to_le32(EXT2_FLAGS_UNSIGNED_HASH); - sbi->s_hash_unsigned = 3; + if (!(sb->s_flags & MS_RDONLY)) + es->s_flags |= + cpu_to_le32(EXT2_FLAGS_UNSIGNED_HASH); + sbi->s_hash_unsigned = 3; #else - es->s_flags |= cpu_to_le32(EXT2_FLAGS_SIGNED_HASH); + if (!(sb->s_flags & MS_RDONLY)) + es->s_flags |= + cpu_to_le32(EXT2_FLAGS_SIGNED_HASH); #endif + } } /* Handle clustersize */ |