reiserfs_fs.h

linux得一些常用命令,以及linux环境下的c编程

   our papers.)*/

#define MAX_FREE_BLOCK 7	/* size of the array of buffers to free at end of do_balance */

/* maximum number of FEB blocknrs on a single level */
#define MAX_AMOUNT_NEEDED 2

/* someday somebody will prefix every field in this struct with tb_ */
struct tree_balance
{
  int tb_mode;
  int need_balance_dirty;
  struct super_block * tb_sb;
  struct reiserfs_transaction_handle *transaction_handle ;
  struct path * tb_path;
  struct buffer_head * L[MAX_HEIGHT];        /* array of left neighbors of nodes in the path */
  struct buffer_head * R[MAX_HEIGHT];        /* array of right neighbors of nodes in the path*/
  struct buffer_head * FL[MAX_HEIGHT];       /* array of fathers of the left  neighbors      */
  struct buffer_head * FR[MAX_HEIGHT];       /* array of fathers of the right neighbors      */
  struct buffer_head * CFL[MAX_HEIGHT];      /* array of common parents of center node and its left neighbor  */
  struct buffer_head * CFR[MAX_HEIGHT];      /* array of common parents of center node and its right neighbor */

  struct buffer_head * FEB[MAX_FEB_SIZE]; /* array of empty buffers. Number of buffers in array equals
					     cur_blknum. */
  struct buffer_head * used[MAX_FEB_SIZE];
  struct buffer_head * thrown[MAX_FEB_SIZE];
  int lnum[MAX_HEIGHT];	/* array of number of items which must be
			   shifted to the left in order to balance the
			   current node; for leaves includes item that
			   will be partially shifted; for internal
			   nodes, it is the number of child pointers
			   rather than items. It includes the new item
			   being created. The code sometimes subtracts
			   one to get the number of wholly shifted
			   items for other purposes. */
  int rnum[MAX_HEIGHT];	/* substitute right for left in comment above */
  int lkey[MAX_HEIGHT];               /* array indexed by height h mapping the key delimiting L[h] and
					       S[h] to its item number within the node CFL[h] */
  int rkey[MAX_HEIGHT];               /* substitute r for l in comment above */
  int insert_size[MAX_HEIGHT];        /* the number of bytes by we are trying to add or remove from
					       S[h]. A negative value means removing.  */
  int blknum[MAX_HEIGHT];             /* number of nodes that will replace node S[h] after
					       balancing on the level h of the tree.  If 0 then S is
					       being deleted, if 1 then S is remaining and no new nodes
					       are being created, if 2 or 3 then 1 or 2 new nodes is
					       being created */

  /* fields that are used only for balancing leaves of the tree */
  int cur_blknum;	/* number of empty blocks having been already allocated			*/
  int s0num;             /* number of items that fall into left most  node when S[0] splits	*/
  int s1num;             /* number of items that fall into first  new node when S[0] splits	*/
  int s2num;             /* number of items that fall into second new node when S[0] splits	*/
  int lbytes;            /* number of bytes which can flow to the left neighbor from the	left	*/
  /* most liquid item that cannot be shifted from S[0] entirely		*/
  /* if -1 then nothing will be partially shifted */
  int rbytes;            /* number of bytes which will flow to the right neighbor from the right	*/
  /* most liquid item that cannot be shifted from S[0] entirely		*/
  /* if -1 then nothing will be partially shifted                           */
  int s1bytes;		/* number of bytes which flow to the first  new node when S[0] splits	*/
            			/* note: if S[0] splits into 3 nodes, then items do not need to be cut	*/
  int s2bytes;
  struct buffer_head * buf_to_free[MAX_FREE_BLOCK]; /* buffers which are to be freed after do_balance finishes by unfix_nodes */
  char * vn_buf;		/* kmalloced memory. Used to create
				   virtual node and keep map of
				   dirtied bitmap blocks */
  int vn_buf_size;		/* size of the vn_buf */
  struct virtual_node * tb_vn;	/* VN starts after bitmap of bitmap blocks */

  int fs_gen;                  /* saved value of `reiserfs_generation' counter
			          see FILESYSTEM_CHANGED() macro in reiserfs_fs.h */
#ifdef DISPLACE_NEW_PACKING_LOCALITIES
  struct key  key;	      /* key pointer, to pass to block allocator or
				 another low-level subsystem */
#endif
} ;

/* These are modes of balancing */

/* When inserting an item. */
#define M_INSERT	'i'
/* When inserting into (directories only) or appending onto an already
   existant item. */
#define M_PASTE		'p'
/* When deleting an item. */
#define M_DELETE	'd'
/* When truncating an item or removing an entry from a (directory) item. */
#define M_CUT 		'c'

/* used when balancing on leaf level skipped (in reiserfsck) */
#define M_INTERNAL	'n'

/* When further balancing is not needed, then do_balance does not need
   to be called. */
#define M_SKIP_BALANCING 		's'
#define M_CONVERT	'v'

/* modes of leaf_move_items */
#define LEAF_FROM_S_TO_L 0
#define LEAF_FROM_S_TO_R 1
#define LEAF_FROM_R_TO_L 2
#define LEAF_FROM_L_TO_R 3
#define LEAF_FROM_S_TO_SNEW 4

#define FIRST_TO_LAST 0
#define LAST_TO_FIRST 1

/* used in do_balance for passing parent of node information that has
   been gotten from tb struct */
struct buffer_info {
    struct tree_balance * tb;
    struct buffer_head * bi_bh;
    struct buffer_head * bi_parent;
    int bi_position;
};


/* there are 4 types of items: stat data, directory item, indirect, direct.
+-------------------+------------+--------------+------------+
|	            |  k_offset  | k_uniqueness | mergeable? |
+-------------------+------------+--------------+------------+
|     stat data     |	0        |      0       |   no       |
+-------------------+------------+--------------+------------+
| 1st directory item| DOT_OFFSET |DIRENTRY_UNIQUENESS|   no       | 
| non 1st directory | hash value |              |   yes      |
|     item          |            |              |            |
+-------------------+------------+--------------+------------+
| indirect item     | offset + 1 |TYPE_INDIRECT |   if this is not the first indirect item of the object
+-------------------+------------+--------------+------------+
| direct item       | offset + 1 |TYPE_DIRECT   | if not this is not the first direct item of the object
+-------------------+------------+--------------+------------+
*/

struct item_operations {
    int (*bytes_number) (struct item_head * ih, int block_size);
    void (*decrement_key) (struct cpu_key *);
    int (*is_left_mergeable) (struct key * ih, unsigned long bsize);
    void (*print_item) (struct item_head *, char * item);
    void (*check_item) (struct item_head *, char * item);

    int (*create_vi) (struct virtual_node * vn, struct virtual_item * vi, 
		      int is_affected, int insert_size);
    int (*check_left) (struct virtual_item * vi, int free, 
			    int start_skip, int end_skip);
    int (*check_right) (struct virtual_item * vi, int free);
    int (*part_size) (struct virtual_item * vi, int from, int to);
    int (*unit_num) (struct virtual_item * vi);
    void (*print_vi) (struct virtual_item * vi);
};


extern struct item_operations stat_data_ops, indirect_ops, direct_ops, 
  direntry_ops;
extern struct item_operations * item_ops [TYPE_ANY + 1];

#define op_bytes_number(ih,bsize)                    item_ops[le_ih_k_type (ih)]->bytes_number (ih, bsize)
#define op_is_left_mergeable(key,bsize)              item_ops[le_key_k_type (le_key_version (key), key)]->is_left_mergeable (key, bsize)
#define op_print_item(ih,item)                       item_ops[le_ih_k_type (ih)]->print_item (ih, item)
#define op_check_item(ih,item)                       item_ops[le_ih_k_type (ih)]->check_item (ih, item)
#define op_create_vi(vn,vi,is_affected,insert_size)  item_ops[le_ih_k_type ((vi)->vi_ih)]->create_vi (vn,vi,is_affected,insert_size)
#define op_check_left(vi,free,start_skip,end_skip) item_ops[(vi)->vi_index]->check_left (vi, free, start_skip, end_skip)
#define op_check_right(vi,free)                      item_ops[(vi)->vi_index]->check_right (vi, free)
#define op_part_size(vi,from,to)                     item_ops[(vi)->vi_index]->part_size (vi, from, to)
#define op_unit_num(vi)				     item_ops[(vi)->vi_index]->unit_num (vi)
#define op_print_vi(vi)                              item_ops[(vi)->vi_index]->print_vi (vi)





#define COMP_KEYS comp_keys
#define COMP_SHORT_KEYS comp_short_keys
/*#define keys_of_same_object comp_short_keys*/

/* number of blocks pointed to by the indirect item */
#define I_UNFM_NUM(p_s_ih)	( ih_item_len(p_s_ih) / UNFM_P_SIZE )

/* the used space within the unformatted node corresponding to pos within the item pointed to by ih */
#define I_POS_UNFM_SIZE(ih,pos,size) (((pos) == I_UNFM_NUM(ih) - 1 ) ? (size) - ih_free_space(ih) : (size))

/* number of bytes contained by the direct item or the unformatted nodes the indirect item points to */


/* get the item header */ 
#define B_N_PITEM_HEAD(bh,item_num) ( (struct item_head * )((bh)->b_data + BLKH_SIZE) + (item_num) )

/* get key */
#define B_N_PDELIM_KEY(bh,item_num) ( (struct key * )((bh)->b_data + BLKH_SIZE) + (item_num) )

/* get the key */
#define B_N_PKEY(bh,item_num) ( &(B_N_PITEM_HEAD(bh,item_num)->ih_key) )

/* get item body */
#define B_N_PITEM(bh,item_num) ( (bh)->b_data + ih_location(B_N_PITEM_HEAD((bh),(item_num))))

/* get the stat data by the buffer header and the item order */
#define B_N_STAT_DATA(bh,nr) \
( (struct stat_data *)((bh)->b_data + ih_location(B_N_PITEM_HEAD((bh),(nr))) ) )

    /* following defines use reiserfs buffer header and item header */

/* get stat-data */
#define B_I_STAT_DATA(bh, ih) ( (struct stat_data * )((bh)->b_data + ih_location(ih)) )

// this is 3976 for size==4096
#define MAX_DIRECT_ITEM_LEN(size) ((size) - BLKH_SIZE - 2*IH_SIZE - SD_SIZE - UNFM_P_SIZE)

/* indirect items consist of entries which contain blocknrs, pos
   indicates which entry, and B_I_POS_UNFM_POINTER resolves to the
   blocknr contained by the entry pos points to */
#define B_I_POS_UNFM_POINTER(bh,ih,pos) le32_to_cpu(*(((unp_t *)B_I_PITEM(bh,ih)) + (pos)))
#define PUT_B_I_POS_UNFM_POINTER(bh,ih,pos, val) do {*(((unp_t *)B_I_PITEM(bh,ih)) + (pos)) = cpu_to_le32(val); } while (0)

struct reiserfs_iget4_args {
    __u32 objectid ;
} ;

/***************************************************************************/
/*                    FUNCTION DECLARATIONS                                */
/***************************************************************************/

/*#ifdef __KERNEL__*/

/* journal.c see journal.c for all the comments here */

#define JOURNAL_TRANS_HALF 1018   /* must be correct to keep the desc and commit structs at 4k */


/* first block written in a commit.  */
struct reiserfs_journal_desc {
  __u32 j_trans_id ;			/* id of commit */
  __u32 j_len ;			/* length of commit. len +1 is the commit block */
  __u32 j_mount_id ;				/* mount id of this trans*/
  __u32 j_realblock[JOURNAL_TRANS_HALF] ; /* real locations for each block */
  char j_magic[12] ;
} ;

/* last block written in a commit */
struct reiserfs_journal_commit {
  __u32 j_trans_id ;			/* must match j_trans_id from the desc block */
  __u32 j_len ;			/* ditto */
  __u32 j_realblock[JOURNAL_TRANS_HALF] ; /* real locations for each block */
  char j_digest[16] ;			/* md5 sum of all the blocks involved, including desc and commit. not used, kill it */
} ;

/* this header block gets written whenever a transaction is considered fully flushed, and is more recent than the
** last fully flushed transaction.  fully flushed means all the log blocks and all the real blocks are on disk,
** and this transaction does not need to be replayed.
*/
struct reiserfs_journal_header {
  __u32 j_last_flush_trans_id ;		/* id of last fully flushed transaction */
  __u32 j_first_unflushed_offset ;      /* offset in the log of where to start replay after a crash */
  __u32 j_mount_id ;
} ;

extern task_queue reiserfs_commit_thread_tq ;
extern wait_queue_head_t reiserfs_commit_thread_wait ;

/* biggest tunable defines are right here */
#define JOURNAL_BLOCK_COUNT 8192 /* number of blocks in the journal */
#define JOURNAL_MAX_BATCH   900 /* max blocks to batch into one transaction, don't make this any bigger than 900 */
#define JOURNAL_MAX_COMMIT_AGE 30 
#define JOURNAL_MAX_TRANS_AGE 30
#define JOURNAL_PER_BALANCE_CNT (3 * (MAX_HEIGHT-2) + 9)

/* both of these can be as low as 1, or as high as you want.  The min is the
** number of 4k bitmap nodes preallocated on mount. New nodes are allocated
** as needed, and released when transactions are committed.  On release, if 
** the current number of nodes is > max, the node is freed, otherwise, 
** it is put on a free list for faster use later.
*/
#define REISERFS_MIN_BITMAP_NODES 10 
#define REISERFS_MAX_BITMAP_NODES 100 

#define JBH_HASH_SHIFT 13 /* these are based on journal hash size of 8192 */
#define JBH_HASH_MASK 8191

/* After several hours of tedious analysis, the following hash
 * function won.  Do not mess with it... -DaveM
 */
/* The two definitions below were borrowed from fs/buffer.c file of Linux kernel
 * sources and are not licensed by Namesys to its non-GPL license customers */
#define _jhashfn(dev,block)	\
	((((dev)<<(JBH_HASH_SHIFT - 6)) ^ ((dev)<<(JBH_HASH_SHIFT - 9))) ^ \
	 (((block)<<(JBH_HASH_SHIFT - 6)) ^ ((block) >> 13) ^ ((block) << (JBH_HASH_SHIFT - 12))))
#define journal_hash(t,dev,block) ((t)[_jhashfn((dev),(block)) & JBH_HASH_MASK])

/* finds n'th buffer with 0 being the start of this commit.  Needs to go away, j_ap_blocks has changed
** since I created this.  One chunk of code in journal.c needs changing before deleting it
*/
#define JOURNAL_BUFFER(j,n) ((j)->j_ap_blocks[((j)->j_start + (n)) % JOURNAL_BLOCK_COUNT])

void reiserfs_commit_for_inode(struct inode *) ;
void reiserfs_update_inode_transaction(struct inode *) ;
void reiserfs_wait_on_write_block(struct super_block *s) ;
void reiserfs_block_writes(struct reiserfs_transaction_handle *th) ;
void reiserfs_allow_writes(struct super_block *s) ;
void reiserfs_check_lock_depth(char *caller) ;
void reiserfs_prepare_for_journal(struct super_block *, struct buffer_head *bh, int wait) ;
void reiserfs_restore_prepared_buffer(struct super_block *, struct buffer_head *bh) ;
int journal_init(struct super_block *) ;
int journal_release(struct reiserfs_transaction_handle*, struct super_block *) ;
int journal_release_error(struct reiserfs_transaction_handle*, struct super_block *) ;
int journal_end(struct reiserfs_transaction_handle *, struct super_block *, unsigned long) ;
int journal_end_sync(struct reiserfs_transaction_handle *, struct super_block *, unsigned long) ;
int journal_mark_dirty_nolog(struct reiserfs_transaction_handle *, struct super_block *, struct buffer_head *bh) ;
int journal_mark_freed(struct reiserfs_transaction_handle *, struct super_block *, unsigned long blocknr) ;
int push_journal_writer(char *w) ;
int pop_journal_writer(int windex) ;
int journal_transaction_should_end(struct reiserfs_transaction_handle *, int) ;
int reiserfs_in_journal(struct super_block *p_s_sb, kdev_t dev, int bmap_nr, int bit_nr, int size, int searchall, unsigned int *next) ;
int journal_begin(struct reiserfs_transaction_handle *, struct super_block *p_s_sb, unsigned long) ;
struct super_block *reiserfs_get_super(kdev_t dev) ;