From 8f888ef846d4481e24c74b4a91ece771d2bcbcb5 Mon Sep 17 00:00:00 2001 From: "Darrick J. Wong" Date: Tue, 22 May 2012 22:43:41 -0400 Subject: [PATCH] jbd2: change disk layout for metadata checksumming Define flags and allocate space in on-disk journal structures to support checksumming of journal metadata. Signed-off-by: Darrick J. Wong Signed-off-by: "Theodore Ts'o" --- fs/jbd2/commit.c | 4 ++-- fs/jbd2/recovery.c | 6 +++--- include/linux/jbd2.h | 30 ++++++++++++++++++++++++++++-- 3 files changed, 33 insertions(+), 7 deletions(-) diff --git a/fs/jbd2/commit.c b/fs/jbd2/commit.c index 840f70f50792..69d780310aea 100644 --- a/fs/jbd2/commit.c +++ b/fs/jbd2/commit.c @@ -627,7 +627,7 @@ void jbd2_journal_commit_transaction(journal_t *journal) tag = (journal_block_tag_t *) tagp; write_tag_block(tag_bytes, tag, jh2bh(jh)->b_blocknr); - tag->t_flags = cpu_to_be32(tag_flag); + tag->t_flags = cpu_to_be16(tag_flag); tagp += tag_bytes; space_left -= tag_bytes; @@ -651,7 +651,7 @@ void jbd2_journal_commit_transaction(journal_t *journal) submitting the IOs. "tag" still points to the last tag we set up. */ - tag->t_flags |= cpu_to_be32(JBD2_FLAG_LAST_TAG); + tag->t_flags |= cpu_to_be16(JBD2_FLAG_LAST_TAG); start_journal_io: for (i = 0; i < bufs; i++) { diff --git a/fs/jbd2/recovery.c b/fs/jbd2/recovery.c index c1a03354a22f..980f3d6b5f88 100644 --- a/fs/jbd2/recovery.c +++ b/fs/jbd2/recovery.c @@ -193,10 +193,10 @@ static int count_tags(journal_t *journal, struct buffer_head *bh) nr++; tagp += tag_bytes; - if (!(tag->t_flags & cpu_to_be32(JBD2_FLAG_SAME_UUID))) + if (!(tag->t_flags & cpu_to_be16(JBD2_FLAG_SAME_UUID))) tagp += 16; - if (tag->t_flags & cpu_to_be32(JBD2_FLAG_LAST_TAG)) + if (tag->t_flags & cpu_to_be16(JBD2_FLAG_LAST_TAG)) break; } @@ -485,7 +485,7 @@ static int do_one_pass(journal_t *journal, unsigned long io_block; tag = (journal_block_tag_t *) tagp; - flags = be32_to_cpu(tag->t_flags); + flags = be16_to_cpu(tag->t_flags); io_block = next_log_block++; wrap(journal, next_log_block); diff --git a/include/linux/jbd2.h b/include/linux/jbd2.h index 912c30a8ddb1..809c439066c5 100644 --- a/include/linux/jbd2.h +++ b/include/linux/jbd2.h @@ -147,12 +147,24 @@ typedef struct journal_header_s #define JBD2_CRC32_CHKSUM 1 #define JBD2_MD5_CHKSUM 2 #define JBD2_SHA1_CHKSUM 3 +#define JBD2_CRC32C_CHKSUM 4 #define JBD2_CRC32_CHKSUM_SIZE 4 #define JBD2_CHECKSUM_BYTES (32 / sizeof(u32)) /* * Commit block header for storing transactional checksums: + * + * NOTE: If FEATURE_COMPAT_CHECKSUM (checksum v1) is set, the h_chksum* + * fields are used to store a checksum of the descriptor and data blocks. + * + * If FEATURE_INCOMPAT_CSUM_V2 (checksum v2) is set, then the h_chksum + * field is used to store crc32c(uuid+commit_block). Each journal metadata + * block gets its own checksum, and data block checksums are stored in + * journal_block_tag (in the descriptor). The other h_chksum* fields are + * not used. + * + * Checksum v1 and v2 are mutually exclusive features. */ struct commit_header { __be32 h_magic; @@ -175,13 +187,19 @@ struct commit_header { typedef struct journal_block_tag_s { __be32 t_blocknr; /* The on-disk block number */ - __be32 t_flags; /* See below */ + __be16 t_checksum; /* truncated crc32c(uuid+seq+block) */ + __be16 t_flags; /* See below */ __be32 t_blocknr_high; /* most-significant high 32bits. */ } journal_block_tag_t; #define JBD2_TAG_SIZE32 (offsetof(journal_block_tag_t, t_blocknr_high)) #define JBD2_TAG_SIZE64 (sizeof(journal_block_tag_t)) +/* Tail of descriptor block, for checksumming */ +struct jbd2_journal_block_tail { + __be32 t_checksum; /* crc32c(uuid+descr_block) */ +}; + /* * The revoke descriptor: used on disk to describe a series of blocks to * be revoked from the log @@ -192,6 +210,10 @@ typedef struct jbd2_journal_revoke_header_s __be32 r_count; /* Count of bytes used in the block */ } jbd2_journal_revoke_header_t; +/* Tail of revoke block, for checksumming */ +struct jbd2_journal_revoke_tail { + __be32 r_checksum; /* crc32c(uuid+revoke_block) */ +}; /* Definitions for the journal tag flags word: */ #define JBD2_FLAG_ESCAPE 1 /* on-disk block is escaped */ @@ -241,7 +263,10 @@ typedef struct journal_superblock_s __be32 s_max_trans_data; /* Limit of data blocks per trans. */ /* 0x0050 */ - __u32 s_padding[44]; + __u8 s_checksum_type; /* checksum type */ + __u8 s_padding2[3]; + __u32 s_padding[42]; + __be32 s_checksum; /* crc32c(superblock) */ /* 0x0100 */ __u8 s_users[16*48]; /* ids of all fs'es sharing the log */ @@ -263,6 +288,7 @@ typedef struct journal_superblock_s #define JBD2_FEATURE_INCOMPAT_REVOKE 0x00000001 #define JBD2_FEATURE_INCOMPAT_64BIT 0x00000002 #define JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT 0x00000004 +#define JBD2_FEATURE_INCOMPAT_CSUM_V2 0x00000008 /* Features known to this kernel version: */ #define JBD2_KNOWN_COMPAT_FEATURES JBD2_FEATURE_COMPAT_CHECKSUM -- 2.34.1