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-rw-r--r--e2fslib/jfs_dat.h64
1 files changed, 64 insertions, 0 deletions
diff --git a/e2fslib/jfs_dat.h b/e2fslib/jfs_dat.h
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+++ b/e2fslib/jfs_dat.h
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+/*
+ * jfs_dat.h --- stripped down header file which only contains the JFS
+ * on-disk data structures
+ */
+
+#define JFS_MAGIC_NUMBER 0xc03b3998U /* The first 4 bytes of /dev/random! */
+
+/*
+ * On-disk structures
+ */
+
+/*
+ * Descriptor block types:
+ */
+
+#define JFS_DESCRIPTOR_BLOCK 1
+#define JFS_COMMIT_BLOCK 2
+#define JFS_SUPERBLOCK 3
+
+/*
+ * Standard header for all descriptor blocks:
+ */
+typedef struct journal_header_s
+{
+ __u32 h_magic;
+ __u32 h_blocktype;
+ __u32 h_sequence;
+} journal_header_t;
+
+
+/*
+ * The block tag: used to describe a single buffer in the journal
+ */
+typedef struct journal_block_tag_s
+{
+ __u32 t_blocknr; /* The on-disk block number */
+ __u32 t_flags; /* See below */
+} journal_block_tag_t;
+
+/* Definitions for the journal tag flags word: */
+#define JFS_FLAG_ESCAPE 1 /* on-disk block is escaped */
+#define JFS_FLAG_SAME_UUID 2 /* block has same uuid as previous */
+#define JFS_FLAG_DELETED 4 /* block deleted by this transaction */
+#define JFS_FLAG_LAST_TAG 8 /* last tag in this descriptor block */
+
+
+/*
+ * The journal superblock
+ */
+typedef struct journal_superblock_s
+{
+ journal_header_t s_header;
+
+ /* Static information describing the journal */
+ __u32 s_blocksize; /* journal device blocksize */
+ __u32 s_maxlen; /* total blocks in journal file */
+ __u32 s_first; /* first block of log information */
+
+ /* Dynamic information describing the current state of the log */
+ __u32 s_sequence; /* first commit ID expected in log */
+ __u32 s_start; /* blocknr of start of log */
+
+} journal_superblock_t;
+