[PATCH 03/23] ext4: Record the checksum algorithm in use in the superblock
From: Darrick J. Wong <hidden>
Date: 2012-01-07 08:28:13
Also in:
linux-fsdevel, lkml
Subsystem:
ext4 file system, filesystems (vfs and infrastructure), the rest · Maintainers:
"Theodore Ts'o", Alexander Viro, Christian Brauner, Linus Torvalds
Record the type of checksum algorithm we're using for metadata in the superblock, in case we ever want/need to change the algorithm. Signed-off-by: Darrick J. Wong <redacted> --- fs/ext4/super.c | 18 ++++++++++++++++++ 1 files changed, 18 insertions(+), 0 deletions(-)
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 3e1329e..de9f78c 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c@@ -111,6 +111,16 @@ static struct file_system_type ext3_fs_type = { #define IS_EXT3_SB(sb) (0) #endif +static int ext4_verify_csum_type(struct super_block *sb, + struct ext4_super_block *es) +{ + if (!EXT4_HAS_RO_COMPAT_FEATURE(sb, + EXT4_FEATURE_RO_COMPAT_METADATA_CSUM)) + return 1; + + return es->s_checksum_type == EXT4_CRC32C_CHKSUM; +} + void *ext4_kvmalloc(size_t size, gfp_t flags) { void *ret;
@@ -3181,6 +3191,14 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent) goto cantfind_ext4; sbi->s_kbytes_written = le64_to_cpu(es->s_kbytes_written); + /* Check for a known checksum algorithm */ + if (!ext4_verify_csum_type(sb, es)) { + ext4_msg(sb, KERN_ERR, "VFS: Found ext4 filesystem with " + "unknown checksum algorithm."); + silent = 1; + goto cantfind_ext4; + } + /* Set defaults before we parse the mount options */ def_mount_opts = le32_to_cpu(es->s_default_mount_opts); set_opt(sb, INIT_INODE_TABLE);