From 1eedf3e52c2ae8f7ad2ad9c010ce5293e0b19ae3 Mon Sep 17 00:00:00 2001 From: "Darrick J. Wong" Date: Thu, 2 Aug 2012 20:47:44 -0400 Subject: [PATCH] libext2fs: record the checksum algorithm in use in the superblock 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 Signed-off-by: Theodore Ts'o --- debugfs/set_fields.c | 1 + lib/e2p/ls.c | 15 ++++++++++++++- lib/ext2fs/csum.c | 9 +++++++++ lib/ext2fs/ext2_err.et.in | 3 +++ lib/ext2fs/ext2fs.h | 1 + lib/ext2fs/openfs.c | 12 ++++++++---- 6 files changed, 36 insertions(+), 5 deletions(-) diff --git a/debugfs/set_fields.c b/debugfs/set_fields.c index a42faa2..4126e7b 100644 --- a/debugfs/set_fields.c +++ b/debugfs/set_fields.c @@ -151,6 +151,7 @@ static struct field_set_info super_fields[] = { { "grp_quota_inum", &set_sb.s_grp_quota_inum, NULL, 4, parse_uint }, { "overhead_blocks", &set_sb.s_overhead_blocks, NULL, 4, parse_uint }, { "checksum", &set_sb.s_checksum, NULL, 4, parse_uint }, + { "checksum_type", &set_sb.s_checksum_type, NULL, 1, parse_uint }, { 0, 0, 0, 0 } }; diff --git a/lib/e2p/ls.c b/lib/e2p/ls.c index f05e16d..d2e84eb 100644 --- a/lib/e2p/ls.c +++ b/lib/e2p/ls.c @@ -196,6 +196,16 @@ static __u64 e2p_free_blocks_count(struct ext2_super_block *super) #define EXT2_GOOD_OLD_REV 0 #endif +static const char *checksum_type(__u8 type) +{ + switch (type) { + case EXT2_CRC32C_CHKSUM: + return "crc32c"; + default: + return "unknown"; + } +} + void list_super2(struct ext2_super_block * sb, FILE *f) { int inode_blocks_per_group; @@ -421,9 +431,12 @@ void list_super2(struct ext2_super_block * sb, FILE *f) fprintf(f, "Group quota inode: %u\n", sb->s_grp_quota_inum); - if (sb->s_feature_ro_compat & EXT4_FEATURE_RO_COMPAT_METADATA_CSUM) + if (sb->s_feature_ro_compat & EXT4_FEATURE_RO_COMPAT_METADATA_CSUM) { + fprintf(f, "Checksum type: %s\n", + checksum_type(sb->s_checksum_type)); fprintf(f, "Checksum: 0x%08x\n", sb->s_checksum); + } } void list_super (struct ext2_super_block * s) diff --git a/lib/ext2fs/csum.c b/lib/ext2fs/csum.c index 4cb242b..e276c5d 100644 --- a/lib/ext2fs/csum.c +++ b/lib/ext2fs/csum.c @@ -30,6 +30,15 @@ #define STATIC static #endif +int ext2fs_verify_csum_type(ext2_filsys fs, struct ext2_super_block *sb) +{ + if (!EXT2_HAS_RO_COMPAT_FEATURE(fs->super, + EXT4_FEATURE_RO_COMPAT_METADATA_CSUM)) + return 1; + + return sb->s_checksum_type == EXT2_CRC32C_CHKSUM; +} + static __u32 ext2fs_superblock_csum(ext2_filsys fs, struct ext2_super_block *sb) { int offset = offsetof(struct ext2_super_block, s_checksum); diff --git a/lib/ext2fs/ext2_err.et.in b/lib/ext2fs/ext2_err.et.in index 0580865..cb63689 100644 --- a/lib/ext2fs/ext2_err.et.in +++ b/lib/ext2fs/ext2_err.et.in @@ -467,4 +467,7 @@ ec EXT2_ET_EXT_ATTR_CSUM_INVALID, ec EXT2_ET_SB_CSUM_INVALID, "Superblock checksum does not match superblock" +ec EXT2_ET_UNKNOWN_CSUM, + "Unknown checksum algorithm" + end diff --git a/lib/ext2fs/ext2fs.h b/lib/ext2fs/ext2fs.h index a6fc7f3..383e049 100644 --- a/lib/ext2fs/ext2fs.h +++ b/lib/ext2fs/ext2fs.h @@ -943,6 +943,7 @@ extern __u32 ext2fs_crc32c_be(__u32 crc, unsigned char const *p, size_t len); extern __u32 ext2fs_crc32c_le(__u32 crc, unsigned char const *p, size_t len); /* csum.c */ +extern int ext2fs_verify_csum_type(ext2_filsys fs, struct ext2_super_block *sb); extern errcode_t ext2fs_superblock_csum_set(ext2_filsys fs, struct ext2_super_block *sb); extern int ext2fs_superblock_csum_verify(ext2_filsys fs, diff --git a/lib/ext2fs/openfs.c b/lib/ext2fs/openfs.c index 2a5c235..48c951d 100644 --- a/lib/ext2fs/openfs.c +++ b/lib/ext2fs/openfs.c @@ -195,10 +195,14 @@ errcode_t ext2fs_open2(const char *name, const char *io_options, if (fs->orig_super) memcpy(fs->orig_super, fs->super, SUPERBLOCK_SIZE); - if (!(fs->flags & EXT2_FLAG_IGNORE_CSUM_ERRORS) && - !ext2fs_superblock_csum_verify(fs, fs->super)) { - retval = EXT2_ET_SB_CSUM_INVALID; - goto cleanup; + if (!(fs->flags & EXT2_FLAG_IGNORE_CSUM_ERRORS)) { + retval = 0; + if (!ext2fs_verify_csum_type(fs, fs->super)) + retval = EXT2_ET_UNKNOWN_CSUM; + if (!ext2fs_superblock_csum_verify(fs, fs->super)) + retval = EXT2_ET_SB_CSUM_INVALID; + if (retval) + goto cleanup; } #ifdef WORDS_BIGENDIAN -- 1.8.3.1