include/scsi/scsicam.h


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/*
 * scsicam.h - SCSI CAM support functions, use for HDIO_GETGEO, etc.
 *
 * Copyright 1993, 1994 Drew Eckhardt
 *      Visionary Computing 
 *      (Unix and Linux consulting and custom programming)
 *      drew@Colorado.EDU
 *	+1 (303) 786-7975
 *
 * For more information, please consult the SCSI-CAM draft.
 */

#ifndef SCSICAM_H
#define SCSICAM_H
extern int scsicam_bios_param (struct block_device *bdev, sector_t capacity, int *ip);
extern int scsi_partsize(unsigned char *buf, unsigned long capacity,
           unsigned int  *cyls, unsigned int *hds, unsigned int *secs);
extern unsigned char *scsi_bios_ptable(struct block_device *bdev);
#endif /* def SCSICAM_H */
/*
 * linux/include/linux/jbd.h
 *
 * Written by Stephen C. Tweedie <sct@redhat.com>
 *
 * Copyright 1998-2000 Red Hat, Inc --- All Rights Reserved
 *
 * This file is part of the Linux kernel and is made available under
 * the terms of the GNU General Public License, version 2, or at your
 * option, any later version, incorporated herein by reference.
 *
 * Definitions for transaction data structures for the buffer cache
 * filesystem journaling support.
 */

#ifndef _LINUX_JBD_H
#define _LINUX_JBD_H

/* Allow this file to be included directly into e2fsprogs */
#ifndef __KERNEL__
#include "jfs_compat.h"
#define JFS_DEBUG
#define jfs_debug jbd_debug
#else

#include <linux/types.h>
#include <linux/buffer_head.h>
#include <linux/journal-head.h>
#include <linux/stddef.h>
#include <linux/bit_spinlock.h>
#include <linux/mutex.h>
#include <linux/timer.h>
#include <linux/lockdep.h>
#include <linux/slab.h>

#define journal_oom_retry 1

/*
 * Define JBD_PARANOID_IOFAIL to cause a kernel BUG() if ext3 finds
 * certain classes of error which can occur due to failed IOs.  Under
 * normal use we want ext3 to continue after such errors, because
 * hardware _can_ fail, but for debugging purposes when running tests on
 * known-good hardware we may want to trap these errors.
 */
#undef JBD_PARANOID_IOFAIL

/*
 * The default maximum commit age, in seconds.
 */
#define JBD_DEFAULT_MAX_COMMIT_AGE 5

#ifdef CONFIG_JBD_DEBUG
/*
 * Define JBD_EXPENSIVE_CHECKING to enable more expensive internal
 * consistency checks.  By default we don't do this unless
 * CONFIG_JBD_DEBUG is on.
 */
#define JBD_EXPENSIVE_CHECKING
extern u8 journal_enable_debug;

#define jbd_debug(n, f, a...)						\
	do {								\
		if ((n) <= journal_enable_debug) {			\
			printk (KERN_DEBUG "(%s, %d): %s: ",		\
				__FILE__, __LINE__, __func__);	\
			printk (f, ## a);				\
		}							\
	} while (0)
#else
#define jbd_debug(f, a...)	/**/
#endif

static inline void *jbd_alloc(size_t size, gfp_t flags)
{
	return (void *)__get_free_pages(flags, get_order(size));
}

static inline void jbd_free(void *ptr, size_t size)
{
	free_pages((unsigned long)ptr, get_order(size));
};

#define JFS_MIN_JOURNAL_BLOCKS 1024


/**
 * typedef handle_t - The handle_t type represents a single atomic update being performed by some process.
 *
 * All filesystem modifications made by the process go
 * through this handle.  Recursive operations (such as quota operations)
 * are gathered into a single update.
 *
 * The buffer credits field is used to account for journaled buffers
 * being modified by the running process.  To ensure that there is
 * enough log space for all outstanding operations, we need to limit the
 * number of outstanding buffers possible at any time.  When the
 * operation completes, any buffer credits not used are credited back to
 * the transaction, so that at all times we know how many buffers the
 * outstanding updates on a transaction might possibly touch.
 *
 * This is an opaque datatype.
 **/
typedef struct handle_s		handle_t;	/* Atomic operation type */


/**
 * typedef journal_t - The journal_t maintains all of the journaling state information for a single filesystem.
 *
 * journal_t is linked to from the fs superblock structure.
 *
 * We use the journal_t to keep track of all outstanding transaction
 * activity on the filesystem, and to manage the state of the log
 * writing process.
 *
 * This is an opaque datatype.
 **/
typedef struct journal_s	journal_t;	/* Journal control structure */
#endif

/*
 * Internal structures used by the logging mechanism:
 */

#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_V1	3
#define JFS_SUPERBLOCK_V2	4
#define JFS_REVOKE_BLOCK	5

/*
 * Standard header for all descriptor blocks:
 */
typedef struct journal_header_s
{
	__be32		h_magic;
	__be32		h_blocktype;
	__be32		h_sequence;
} journal_header_t;


/*
 * The block tag: used to describe a single buffer in the journal
 */
typedef struct journal_block_tag_s
{
	__be32		t_blocknr;	/* The on-disk block number */
	__be32		t_flags;	/* See below */
} journal_block_tag_t;

/*
 * The revoke descriptor: used on disk to describe a series of blocks to
 * be revoked from the log
 */
typedef struct journal_revoke_header_s
{
	journal_header_t r_header;
	__be32		 r_count;	/* Count of bytes used in the block */
} journal_revoke_header_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.  All fields are in big-endian byte order.
 */
typedef struct journal_superblock_s
{
/* 0x0000 */
	journal_header_t s_header;

/* 0x000C */
	/* Static information describing the journal */
	__be32	s_blocksize;		/* journal device blocksize */
	__be32	s_maxlen;		/* total blocks in journal file */
	__be32	s_first;		/* first block of log information */

/* 0x0018 */
	/* Dynamic information describing the current state of the log */
	__be32	s_sequence;		/* first commit ID expected in log */
	__be32	s_start;		/* blocknr of start of log */

/* 0x0020 */
	/* Error value, as set by journal_abort(). */
	__be32	s_errno;

/* 0x0024 */
	/* Remaining fields are only valid in a version-2 superblock */
	__be32	s_feature_compat;	/* compatible feature set */
	__be32	s_feature_incompat;	/* incompatible feature set */
	__be32	s_feature_ro_compat;	/* readonly-compatible feature set */
/* 0x0030 */
	__u8	s_uuid[16];		/* 128-bit uuid for journal */

/* 0x0040 */
	__be32	s_nr_users;		/* Nr of filesystems sharing log */

	__be32	s_dynsuper;		/* Blocknr of dynamic superblock copy*/

/* 0x0048 */
	__be32	s_max_transaction;	/* Limit of journal blocks per trans.*/
	__be32	s_max_trans_data;	/* Limit of data blocks per trans. */

/* 0x0050 */
	__u32	s_padding[44];

/* 0x0100 */
	__u8	s_users[16*48];		/* ids of all fs'es sharing the log */
/* 0x0400 */
} journal_superblock_t;

#define JFS_HAS_COMPAT_FEATURE(j,mask)					\
	((j)->j_format_version >= 2 &&					\
	 ((j)->j_superblock->s_feature_compat & cpu_to_be32((mask))))
#define JFS_HAS_RO_COMPAT_FEATURE(j,mask)				\
	((j)->j_format_version >= 2 &&					\
	 ((j)->j_superblock->s_feature_ro_compat & cpu_to_be32((mask))))
#define JFS_HAS_INCOMPAT_FEATURE(j,mask)				\
	((j)->j_format_version >= 2 &&					\
	 ((j)->j_superblock->s_feature_incompat & cpu_to_be32((mask))))

#define JFS_FEATURE_INCOMPAT_REVOKE	0x00000001

/* Features known to this kernel version: */
#define JFS_KNOWN_COMPAT_FEATURES	0
#define JFS_KNOWN_ROCOMPAT_FEATURES	0
#define JFS_KNOWN_INCOMPAT_FEATURES	JFS_FEATURE_INCOMPAT_REVOKE

#ifdef __KERNEL__

#include <linux/fs.h>
#include <linux/sched.h>
#include <linux/jbd_common.h>

#define J_ASSERT(assert)	BUG_ON(!(assert))

#define J_ASSERT_BH(bh, expr)	J_ASSERT(expr)
#define J_ASSERT_JH(jh, expr)	J_ASSERT(expr)

#if defined(JBD_PARANOID_IOFAIL)
#define J_EXPECT(expr, why...)		J_ASSERT(expr)
#define J_EXPECT_BH(bh, expr, why...)	J_ASSERT_BH(bh, expr)
#define J_EXPECT_JH(jh, expr, why...)	J_ASSERT_JH(jh, expr)
#else
#define __journal_expect(expr, why...)					     \
	({								     \
		int val = (expr);					     \
		if (!val) {						     \
			printk(KERN_ERR					     \
				"EXT3-fs unexpected failure: %s;\n",# expr); \
			printk(KERN_ERR why "\n");			     \
		}							     \
		val;							     \
	})
#define J_EXPECT(expr, why...)		__journal_expect(expr, ## why)
#define J_EXPECT_BH(bh, expr, why...)	__journal_expect(expr, ## why)
#define J_EXPECT_JH(jh, expr, why...)	__journal_expect(expr, ## why)
#endif

struct jbd_revoke_table_s;

/**
 * struct handle_s - this is the concrete type associated with handle_t.
 * @h_transaction: Which compound transaction is this update a part of?
 * @h_buffer_credits: Number of remaining buffers we are allowed to dirty.
 * @h_ref: Reference count on this handle
 * @h_err: Field for caller's use to track errors through large fs operations
 * @h_sync: flag for sync-on-close
 * @h_jdata: flag to force data journaling
 * @h_aborted: flag indicating fatal error on handle
 * @h_lockdep_map: lockdep info for debugging lock problems
 */
struct handle_s
{
	/* Which compound transaction is this update a part of? */
	transaction_t		*h_transaction;

	/* Number of remaining buffers we are allowed to dirty: */
	int			h_buffer_credits;

	/* Reference count on this handle */
	int			h_ref;

	/* Field for caller's use to track errors through large fs */
	/* operations */
	int			h_err;

	/* Flags [no locking] */
	unsigned int	h_sync:		1;	/* sync-on-close */
	unsigned int	h_jdata:	1;	/* force data journaling */
	unsigned int	h_aborted:	1;	/* fatal error on handle */

#ifdef CONFIG_DEBUG_LOCK_ALLOC
	struct lockdep_map	h_lockdep_map;
#endif
};


/* The transaction_t type is the guts of the journaling mechanism.  It
 * tracks a compound transaction through its various states:
 *
 * RUNNING:	accepting new updates
 * LOCKED:	Updates still running but we don't accept new ones
 * RUNDOWN:	Updates are tidying up but have finished requesting
 *		new buffers to modify (state not used for now)
 * FLUSH:       All updates complete, but we are still writing to disk
 * COMMIT:      All data on disk, writing commit record
 * FINISHED:	We still have to keep the transaction for checkpointing.
 *
 * The transaction keeps track of all of the buffers modified by a
 * running transaction, and all of the buffers committed but not yet
 * flushed to home for finished transactions.
 */

/*
 * Lock ranking:
 *
 *    j_list_lock
 *      ->jbd_lock_bh_journal_head()	(This is "innermost")
 *
 *    j_state_lock
 *    ->jbd_lock_bh_state()
 *
 *    jbd_lock_bh_state()
 *    ->j_list_lock
 *
 *    j_state_lock
 *    ->t_handle_lock
 *
 *    j_state_lock
 *    ->j_list_lock			(journal_unmap_buffer)
 *
 */

struct transaction_s
{
	/* Pointer to the journal for this transaction. [no locking] */
	journal_t		*t_journal;

	/* Sequence number for this transaction [no locking] */
	tid_t			t_tid;

	/*
	 * Transaction's current state
	 * [no locking - only kjournald alters this]
	 * [j_list_lock] guards transition of a transaction into T_FINISHED
	 * state and subsequent call of __journal_drop_transaction()
	 * FIXME: needs barriers
	 * KLUDGE: [use j_state_lock]
	 */
	enum {
		T_RUNNING,
		T_LOCKED,
		T_FLUSH,
		T_COMMIT,
		T_COMMIT_RECORD,
		T_FINISHED
	}			t_state;

	/*
	 * Where in the log does this transaction's commit start? [no locking]
	 */
	unsigned int		t_log_start;

	/* Number of buffers on the t_buffers list [j_list_lock] */
	int			t_nr_buffers;

	/*
	 * Doubly-linked circular list of all buffers reserved but not yet
	 * modified by this transaction [j_list_lock]
	 */
	struct journal_head	*t_reserved_list;

	/*
	 * Doubly-linked circular list of all buffers under writeout during
	 * commit [j_list_lock]
	 */
	struct journal_head	*t_locked_list;

	/*
	 * Doubly-linked circular list of all metadata buffers owned by this
	 * transaction [j_list_lock]
	 */
	struct journal_head	*t_buffers;

	/*
	 * Doubly-linked circular list of all data buffers still to be
	 * flushed before this transaction can be committed [j_list_lock]
	 */
	struct journal_head	*t_sync_datalist;

	/*
	 * Doubly-linked circular list of all forget buffers (superseded
	 * buffers which we can un-checkpoint once this transaction commits)
	 * [j_list_lock]
	 */
	struct journal_head	*t_forget;

	/*
	 * Doubly-linked circular list of all buffers still to be flushed before
	 * this transaction can be checkpointed. [j_list_lock]
	 */
	struct journal_head	*t_checkpoint_list;

	/*
	 * Doubly-linked circular list of all buffers submitted for IO while
	 * checkpointing. [j_list_lock]
	 */
	struct journal_head	*t_checkpoint_io_list;

	/*
	 * Doubly-linked circular list of temporary buffers currently undergoing
	 * IO in the log [j_list_lock]
	 */
	struct journal_head	*t_iobuf_list;

	/*
	 * Doubly-linked circular list of metadata buffers being shadowed by log
	 * IO.  The IO buffers on the iobuf list and the shadow buffers on this
	 * list match each other one for one at all times. [j_list_lock]
	 */
	struct journal_head	*t_shadow_list;

	/*
	 * Doubly-linked circular list of control buffers being written to the
	 * log. [j_list_lock]
	 */
	struct journal_head	*t_log_list;

	/*
	 * Protects info related to handles
	 */
	spinlock_t		t_handle_lock;

	/*
	 * Number of outstanding updates running on this transaction
	 * [t_handle_lock]
	 */
	int			t_updates;

	/*
	 * Number of buffers reserved for use by all handles in this transaction
	 * handle but not yet modified. [t_handle_lock]
	 */
	int			t_outstanding_credits;

	/*
	 * Forward and backward links for the circular list of all transactions
	 * awaiting checkpoint. [j_list_lock]
	 */
	transaction_t		*t_cpnext, *t_cpprev;

	/*
	 * When will the transaction expire (become due for commit), in jiffies?
	 * [no locking]
	 */
	unsigned long		t_expires;

	/*
	 * When this transaction started, in nanoseconds [no locking]
	 */
	ktime_t			t_start_time;

	/*
	 * How many handles used this transaction? [t_handle_lock]
	 */
	int t_handle_count;
};

/**
 * struct journal_s - this is the concrete type associated with journal_t.
 * @j_flags:  General journaling state flags
 * @j_errno:  Is there an outstanding uncleared error on the journal (from a
 *     prior abort)?
 * @j_sb_buffer: First part of superblock buffer
 * @j_superblock: Second part of superblock buffer
 * @j_format_version: Version of the superblock format
 * @j_state_lock: Protect the various scalars in the journal
 * @j_barrier_count:  Number of processes waiting to create a barrier lock
 * @j_running_transaction: The current running transaction..
 * @j_committing_transaction: the transaction we are pushing to disk
 * @j_checkpoint_transactions: a linked circular list of all transactions
 *  waiting for checkpointing
 * @j_wait_transaction_locked: Wait queue for waiting for a locked transaction
 *  to start committing, or for a barrier lock to be released
 * @j_wait_logspace: Wait queue for waiting for checkpointing to complete
 * @j_wait_done_commit: Wait queue for waiting for commit to complete
 * @j_wait_checkpoint:  Wait queue to trigger checkpointing
 * @j_wait_commit: Wait queue to trigger commit
 * @j_wait_updates: Wait queue to wait for updates to complete
 * @j_checkpoint_mutex: Mutex for locking against concurrent checkpoints
 * @j_head: Journal head - identifies the first unused block in the journal
 * @j_tail: Journal tail - identifies the oldest still-used block in the
 *  journal.
 * @j_free: Journal free - how many free blocks are there in the journal?
 * @j_first: The block number of the first usable block
 * @j_last: The block number one beyond the last usable block
 * @j_dev: Device where we store the journal
 * @j_blocksize: blocksize for the location where we store the journal.
 * @j_blk_offset: starting block offset for into the device where we store the
 *     journal
 * @j_fs_dev: Device which holds the client fs.  For internal journal this will
 *     be equal to j_dev
 * @j_maxlen: Total maximum capacity of the journal region on disk.
 * @j_list_lock: Protects the buffer lists and internal buffer state.