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authorTheodore Ts'o <tytso@mit.edu>2014-02-12 12:16:04 -0500
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-03-06 21:30:00 -0800
commitf13ea132887a8649cc6d45942e2be27f4362351f (patch)
tree880ff32e4f47c2693b8c2de58c60072fb964eb8c
parent4687eb1ebf2129cf46e636ec197173b99a4959e2 (diff)
downloadlinaro-lsk-f13ea132887a8649cc6d45942e2be27f4362351f.tar.gz
ext4: don't try to modify s_flags if the the file system is read-only
commit 23301410972330c0ae9a8afc379ba2005e249cc6 upstream. 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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--fs/ext4/super.c20
1 files changed, 13 insertions, 7 deletions
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index e4923b6a9e3..a7a5f7ea74d 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -3592,16 +3592,22 @@ 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 */