ref: 890f937d5373c9b76bd954253c6360f9f06bfdfb
parent: 08450828b9e7998fb4316725abc4862761f9ed75
author: ngkaho1234 <ngkaho1234@gmail.com>
date: Fri Nov 13 18:38:37 EST 2015
Journalling(JBD) support skeletal code.
--- /dev/null
+++ b/lwext4/ext4_journal.c
@@ -1,0 +1,48 @@
+/**
+ * @file ext4_journal.c
+ * @brief Journalling
+ */
+
+#include "ext4_config.h"
+#include "ext4_types.h"
+#include "ext4_fs.h"
+#include "ext4_errno.h"
+#include "ext4_blockdev.h"
+#include "ext4_crc32c.h"
+#include "ext4_debug.h"
+
+#include <string.h>
+
+int jbd_get_fs(struct ext4_fs *fs,
+ struct jbd_fs *jbd_fs)
+{+ int rc;
+ uint32_t journal_ino;
+
+ memset(jbd_fs, 0, sizeof(struct jbd_fs));
+ journal_ino = ext4_get32(&fs->sb, journal_inode_number);
+
+ rc = ext4_fs_get_inode_ref(fs,
+ journal_ino,
+ &jbd_fs->inode_ref);
+ return rc;
+}
+
+int jbd_put_fs(struct jbd_fs *jbd_fs)
+{+ int rc;
+ rc = ext4_fs_put_inode_ref(&jbd_fs->inode_ref);
+ return rc;
+}
+
+int jbd_bmap(struct jbd_fs *jbd_fs,
+ ext4_lblk_t iblock,
+ ext4_fsblk_t *fblock)
+{+ int rc = ext4_fs_get_inode_data_block_index(
+ &jbd_fs->inode_ref,
+ iblock,
+ fblock,
+ false);
+ return rc;
+}
--- a/lwext4/ext4_types.h
+++ b/lwext4/ext4_types.h
@@ -55,6 +55,8 @@
#define EXT4_CHECKSUM_CRC32C 1
+#define UUID_SIZE 16
+
/*
* Structure of the super block
*/
@@ -92,7 +94,7 @@
uint32_t features_compatible; /* Compatible feature set */
uint32_t features_incompatible; /* Incompatible feature set */
uint32_t features_read_only; /* Readonly-compatible feature set */
- uint8_t uuid[16]; /* 128-bit uuid for volume */
+ uint8_t uuid[UUID_SIZE]; /* 128-bit uuid for volume */
char volume_name[16]; /* Volume name */
char last_mounted[64]; /* Directory where last mounted */
uint32_t algorithm_usage_bitmap; /* For compression */
@@ -108,7 +110,7 @@
/*
* Journaling support valid if EXT4_FEATURE_COMPAT_HAS_JOURNAL set.
*/
- uint8_t journal_uuid[16]; /* UUID of journal superblock */
+ uint8_t journal_uuid[UUID_SIZE]; /* UUID of journal superblock */
uint32_t journal_inode_number; /* Inode number of journal file */
uint32_t journal_dev; /* Device number of journal file */
uint32_t last_orphan; /* Head of list of inodes to delete */
@@ -893,6 +895,196 @@
/*****************************************************************************/
+/*
+ * JBD stores integers in big endian.
+ */
+
+#define JBD_MAGIC_NUMBER 0xc03b3998U /* The first 4 bytes of /dev/random! */
+
+/*
+ * Descriptor block types:
+ */
+
+#define JBD_DESCRIPTOR_BLOCK 1
+#define JBD_COMMIT_BLOCK 2
+#define JBD_SUPERBLOCK 3
+#define JBD_SUPERBLOCK_V2 4
+#define JBD_REVOKE_BLOCK 5
+
+/*
+ * Standard header for all descriptor blocks:
+ */
+struct jbd_bhdr {+ uint32_t magic;
+ uint32_t blocktype;
+ uint32_t sequence;
+};
+
+/*
+ * Checksum types.
+ */
+#define JBD_CRC32_CHKSUM 1
+#define JBD_MD5_CHKSUM 2
+#define JBD_SHA1_CHKSUM 3
+#define JBD_CRC32C_CHKSUM 4
+
+#define JBD_CRC32_CHKSUM_SIZE 4
+
+#define JBD_CHECKSUM_BYTES (32 / sizeof(uint32_t))
+/*
+ * 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.
+ *
+ * If FEATURE_INCOMPAT_CSUM_V3 is set, the descriptor block uses
+ * journal_block_tag3_t to store a full 32-bit checksum. Everything else
+ * is the same as v2.
+ *
+ * Checksum v1, v2, and v3 are mutually exclusive features.
+ */
+struct jbd_commit_header {+ struct jbd_bhdr header;
+ uint8_t chksum_type;
+ uint8_t chksum_size;
+ uint8_t padding[2];
+ uint32_t chksum[JBD_CHECKSUM_BYTES];
+ uint64_t commit_sec;
+ uint32_t commit_nsec;
+};
+
+/*
+ * The block tag: used to describe a single buffer in the journal
+ */
+struct jbd_block_tag3 {+ uint32_t blocknr; /* The on-disk block number */
+ uint32_t flags; /* See below */
+ uint32_t blocknr_high; /* most-significant high 32bits. */
+ uint32_t checksum; /* crc32c(uuid+seq+block) */
+};
+
+struct jbd_block_tag {+ uint32_t blocknr; /* The on-disk block number */
+ uint16_t checksum; /* truncated crc32c(uuid+seq+block) */
+ uint16_t flags; /* See below */
+ uint32_t blocknr_high; /* most-significant high 32bits. */
+};
+
+/* Tail of descriptor block, for checksumming */
+struct jbd_block_tail {+ uint32_t checksum;
+};
+
+/*
+ * The revoke descriptor: used on disk to describe a series of blocks to
+ * be revoked from the log
+ */
+struct jbd_revoke_header {+ struct jbd_bhdr header;
+ uint32_t count; /* Count of bytes used in the block */
+};
+
+/* Tail of revoke block, for checksumming */
+struct jbd_revoke_tail {+ uint32_t checksum;
+};
+
+#define JBD_USERS_MAX 48
+#define JBD_USERS_SIZE (UUID_SIZE * JBD_USERS_MAX)
+
+/*
+ * The journal superblock. All fields are in big-endian byte order.
+ */
+struct jbd_sb {+/* 0x0000 */
+ struct jbd_bhdr header;
+
+/* 0x000C */
+ /* Static information describing the journal */
+ uint32_t blocksize; /* journal device blocksize */
+ uint32_t maxlen; /* total blocks in journal file */
+ uint32_t first; /* first block of log information */
+
+/* 0x0018 */
+ /* Dynamic information describing the current state of the log */
+ uint32_t sequence; /* first commit ID expected in log */
+ uint32_t start; /* blocknr of start of log */
+
+/* 0x0020 */
+ /* Error value, as set by journal_abort(). */
+ int32_t error_val;
+
+/* 0x0024 */
+ /* Remaining fields are only valid in a version-2 superblock */
+ uint32_t feature_compat; /* compatible feature set */
+ uint32_t feature_incompat; /* incompatible feature set */
+ uint32_t feature_ro_compat; /* readonly-compatible feature set */
+/* 0x0030 */
+ uint8_t uuid[UUID_SIZE]; /* 128-bit uuid for journal */
+
+/* 0x0040 */
+ uint32_t nr_users; /* Nr of filesystems sharing log */
+
+ uint32_t dynsuper; /* Blocknr of dynamic superblock copy*/
+
+/* 0x0048 */
+ uint32_t max_transaction; /* Limit of journal blocks per trans.*/
+ uint32_t max_trandata; /* Limit of data blocks per trans. */
+
+/* 0x0050 */
+ uint8_t checksum_type; /* checksum type */
+ uint8_t padding2[3];
+ uint32_t padding[42];
+ uint32_t checksum; /* crc32c(superblock) */
+
+/* 0x0100 */
+ uint8_t users[JBD_USERS_SIZE]; /* ids of all fs'es sharing the log */
+
+/* 0x0400 */
+};
+
+#define JBD_HAS_COMPAT_FEATURE(jsb,mask) \
+ ((jsb)->header.blocktype >= to_be32(2) && \
+ ((jsb)->feature_compat & to_be32((mask))))
+#define JBD_HAS_RO_COMPAT_FEATURE(jsb,mask) \
+ ((jsb)->header.blocktype >= to_be32(2) && \
+ ((jsb)->feature_ro_compat & to_be32((mask))))
+#define JBD_HAS_INCOMPAT_FEATURE(jsb,mask) \
+ ((jsb)->header.blocktype >= to_be32(2) && \
+ ((jsb)->feature_incompat & to_be32((mask))))
+
+#define JBD_FEATURE_COMPAT_CHECKSUM 0x00000001
+
+#define JBD_FEATURE_INCOMPAT_REVOKE 0x00000001
+#define JBD_FEATURE_INCOMPAT_64BIT 0x00000002
+#define JBD_FEATURE_INCOMPAT_ASYNC_COMMIT 0x00000004
+#define JBD_FEATURE_INCOMPAT_CSUM_V2 0x00000008
+#define JBD_FEATURE_INCOMPAT_CSUM_V3 0x00000010
+
+/* Features known to this kernel version: */
+#define JBD_KNOWN_COMPAT_FEATURES 0
+#define JBD_KNOWN_ROCOMPAT_FEATURES 0
+#define JBD_KNOWN_INCOMPAT_FEATURES (JBD_FEATURE_INCOMPAT_REVOKE|\
+ JBD_FEATURE_INCOMPAT_ASYNC_COMMIT|\
+ JBD_FEATURE_INCOMPAT_64BIT|\
+ JBD_FEATURE_INCOMPAT_CSUM_V2|\
+ JBD_FEATURE_INCOMPAT_CSUM_V3)
+
+struct jbd_fs {+ /* If journal block device is used, bdev will be non-null */
+ struct ext4_blockdev *bdev;
+ struct ext4_inode_ref inode_ref;
+ struct jbd_sb sb;
+};
+
+/*****************************************************************************/
+
#define EXT4_CRC32_INIT (0xFFFFFFFFUL)
/*****************************************************************************/
@@ -917,10 +1109,35 @@
return ((n & 0xff) << 8) | ((n & 0xff00) >> 8);
}
+#define to_be64(_n) _n
+#define to_be32(_n) _n
+#define to_be16(_n) _n
+
#else
#define to_le64(_n) _n
#define to_le32(_n) _n
#define to_le16(_n) _n
+
+static inline uint64_t to_be64(uint64_t n)
+{+ return ((n & 0xff) << 56) | ((n & 0xff00) << 40) |
+ ((n & 0xff0000) << 24) | ((n & 0xff000000LL) << 8) |
+ ((n & 0xff00000000LL) >> 8) | ((n & 0xff0000000000LL) >> 24) |
+ ((n & 0xff000000000000LL) >> 40) |
+ ((n & 0xff00000000000000LL) >> 56);
+}
+
+static inline uint32_t to_be32(uint32_t n)
+{+ return ((n & 0xff) << 24) | ((n & 0xff00) << 8) |
+ ((n & 0xff0000) >> 8) | ((n & 0xff000000) >> 24);
+}
+
+static inline uint16_t to_be16(uint16_t n)
+{+ return ((n & 0xff) << 8) | ((n & 0xff00) >> 8);
+}
+
#endif
/****************************Access macros to ext4 structures*****************/