fs.h

嵌入式ARM的一些源代码

#ifndef _LINUX_FS_H
#define _LINUX_FS_H

/*
 * This file has definitions for some important file table
 * structures etc.
 */

#include <linux/config.h>
#include <linux/linkage.h>
#include <linux/limits.h>
#include <linux/wait.h>
#include <linux/types.h>
#include <linux/vfs.h>
#include <linux/net.h>
#include <linux/kdev_t.h>
#include <linux/ioctl.h>

/*
 * It's silly to have NR_OPEN bigger than NR_FILE, but I'll fix
 * that later. Anyway, now the file code is no longer dependent
 * on bitmaps in unsigned longs, but uses the new fd_set structure..
 *
 * Some programs (notably those using select()) may have to be 
 * recompiled to take full advantage of the new limits..
 */

/* Fixed constants first: */
#undef NR_OPEN

#ifdef CONFIG_REDUCED_MEMORY
/* Originally 256: 116 would be neat because a files_struct becomes exactly 500 bytes,
   a relatively cool figure for kmalloc, but problems reducing fd_select made this not worth it.
   Currently 128. */
#define NR_OPEN 128 /*256*/

#define NR_SUPER 8 /*64*/

#else /* !CONFIG_REDUCED_MEMORY */

#define NR_OPEN 256

#define NR_SUPER 64
#endif /* !CONFIG_REDUCED_MEMORY */
#define BLOCK_SIZE 1024
#define BLOCK_SIZE_BITS 10

/* And dynamically-tunable limits and defaults: */
extern int max_inodes, nr_inodes;
extern int max_files, nr_files;

#ifdef CONFIG_REDUCED_MEMORY
#define NR_INODE 200/*64*/ /*3072*/
#define NR_FILE 128/*116*/ /*1024*/
#else /* !CONFIG_REDUCED_MEMORY */
#define NR_INODE 3072	/* this should be bigger than NR_FILE */
#define NR_FILE 1024	/* this can well be larger on a larger system */
#endif /* !CONFIG_REDUCED_MEMORY */

#define MAY_EXEC 1
#define MAY_WRITE 2
#define MAY_READ 4

#define FMODE_READ 1
#define FMODE_WRITE 2

#define READ 0
#define WRITE 1
#define READA 2		/* read-ahead  - don't block if no resources */
#define WRITEA 3	/* write-ahead - don't block if no resources */

#ifndef NULL
#define NULL ((void *) 0)
#endif

#define NIL_FILP	((struct file *)0)
#define SEL_IN		1
#define SEL_OUT		2
#define SEL_EX		4

/*
 * These are the fs-independent mount-flags: up to 16 flags are supported
 */
#define MS_RDONLY	 1	/* Mount read-only */
#define MS_NOSUID	 2	/* Ignore suid and sgid bits */
#define MS_NODEV	 4	/* Disallow access to device special files */
#define MS_NOEXEC	 8	/* Disallow program execution */
#define MS_SYNCHRONOUS	16	/* Writes are synced at once */
#define MS_REMOUNT	32	/* Alter flags of a mounted FS */
#define MS_MANDLOCK	64	/* Allow mandatory locks on an FS */
#define S_WRITE		128	/* Write on file/directory/symlink */
#define S_APPEND	256	/* Append-only file */
#define S_IMMUTABLE	512	/* Immutable file */
#define MS_NOATIME	1024	/* Do not update access times. */
#define S_BAD_INODE	2048	/* Marker for unreadable inodes */

/*
 * Flags that can be altered by MS_REMOUNT
 */
#define MS_RMT_MASK (MS_RDONLY|MS_NOSUID|MS_NODEV|MS_NOEXEC|MS_SYNCHRONOUS|MS_MANDLOCK|MS_NOATIME)

/*
 * Magic mount flag number. Has to be or-ed to the flag values.
 */
#define MS_MGC_VAL 0xC0ED0000	/* magic flag number to indicate "new" flags */
#define MS_MGC_MSK 0xffff0000	/* magic flag number mask */

/*
 * Note that read-only etc flags are inode-specific: setting some file-system
 * flags just means all the inodes inherit those flags by default. It might be
 * possible to override it selectively if you really wanted to with some
 * ioctl() that is not currently implemented.
 *
 * Exception: MS_RDONLY is always applied to the entire file system.
 */
#define IS_RDONLY(inode) (((inode)->i_sb) && ((inode)->i_sb->s_flags & MS_RDONLY))
#define IS_NOSUID(inode) ((inode)->i_flags & MS_NOSUID)
#define IS_NODEV(inode) ((inode)->i_flags & MS_NODEV)
#define IS_NOEXEC(inode) ((inode)->i_flags & MS_NOEXEC)
#define IS_SYNC(inode) ((inode)->i_flags & MS_SYNCHRONOUS)
#define IS_MANDLOCK(inode) ((inode)->i_flags & MS_MANDLOCK)

#define IS_WRITABLE(inode) ((inode)->i_flags & S_WRITE)
#define IS_APPEND(inode) ((inode)->i_flags & S_APPEND)
#define IS_IMMUTABLE(inode) ((inode)->i_flags & S_IMMUTABLE)
#define IS_NOATIME(inode) ((inode)->i_flags & MS_NOATIME)

#define UPDATE_ATIME(inode) \
	if (!IS_NOATIME(inode) && !IS_RDONLY(inode)) { \
		inode->i_atime = CURRENT_TIME; \
		inode->i_dirt = 1; \
	}

/* the read-only stuff doesn't really belong here, but any other place is
   probably as bad and I don't want to create yet another include file. */

#define BLKROSET   _IO(0x12,93)	/* set device read-only (0 = read-write) */
#define BLKROGET   _IO(0x12,94)	/* get read-only status (0 = read_write) */
#define BLKRRPART  _IO(0x12,95)	/* re-read partition table */
#define BLKGETSIZE _IO(0x12,96)	/* return device size */
#define BLKFLSBUF  _IO(0x12,97)	/* flush buffer cache */
#define BLKRASET   _IO(0x12,98)	/* Set read ahead for block device */
#define BLKRAGET   _IO(0x12,99)	/* get current read ahead setting */

#define BMAP_IOCTL 1		/* obsolete - kept for compatibility */
#define FIBMAP	   _IO(0x00,1)	/* bmap access */
#define FIGETBSZ   _IO(0x00,2)	/* get the block size used for bmap */

#ifdef __KERNEL__

#include <asm/semaphore.h>
#include <asm/bitops.h>

extern void buffer_init(void);
extern unsigned long inode_init(unsigned long start, unsigned long end);
extern unsigned long file_table_init(unsigned long start, unsigned long end);
extern unsigned long name_cache_init(unsigned long start, unsigned long end);

typedef char buffer_block[BLOCK_SIZE];

/* bh state bits */
#define BH_Uptodate	0	/* 1 if the buffer contains valid data */
#define BH_Dirty	1	/* 1 if the buffer is dirty */
#define BH_Lock		2	/* 1 if the buffer is locked */
#define BH_Req		3	/* 0 if the buffer has been invalidated */
#define BH_Touched	4	/* 1 if the buffer has been touched (aging) */
#define BH_Has_aged	5	/* 1 if the buffer has been aged (aging) */
#define BH_Protected	6	/* 1 if the buffer is protected */
#define BH_FreeOnIO	7	/* 1 to discard the buffer_head after IO */

/*
 * Try to keep the most commonly used fields in single cache lines (16
 * bytes) to improve performance.  This ordering should be
 * particularly beneficial on 32-bit processors.
 * 
 * We use the first 16 bytes for the data which is used in searches
 * over the block hash lists (ie. getblk(), find_buffer() and
 * friends).
 * 
 * The second 16 bytes we use for lru buffer scans, as used by
 * sync_buffers() and refill_freelist().  -- sct
 */
struct buffer_head {
	/* First cache line: */
	unsigned long b_blocknr;	/* block number */
	kdev_t b_dev;			/* device (B_FREE = free) */
	kdev_t b_rdev;			/* Real device */
	unsigned long b_rsector;	/* Real buffer location on disk */
	struct buffer_head * b_next;	/* Hash queue list */
	struct buffer_head * b_this_page;	/* circular list of buffers in one page */

	/* Second cache line: */
	unsigned long b_state;		/* buffer state bitmap (see above) */
	struct buffer_head * b_next_free;
	unsigned int b_count;		/* users using this block */
	unsigned long b_size;		/* block size */

	/* Non-performance-critical data follows. */
	char * b_data;			/* pointer to data block (1024 bytes) */
	unsigned int b_list;		/* List that this buffer appears */
	unsigned long b_flushtime;      /* Time when this (dirty) buffer
					 * should be written */
	unsigned long b_lru_time;       /* Time when this buffer was 
					 * last used. */
	struct wait_queue * b_wait;
	struct buffer_head * b_prev;		/* doubly linked list of hash-queue */
	struct buffer_head * b_prev_free;	/* doubly linked list of buffers */
	struct buffer_head * b_reqnext;		/* request queue */
};

static inline int buffer_uptodate(struct buffer_head * bh)
{
	return test_bit(BH_Uptodate, &bh->b_state);
}	

static inline int buffer_dirty(struct buffer_head * bh)
{
	return test_bit(BH_Dirty, &bh->b_state);
}

static inline int buffer_locked(struct buffer_head * bh)
{
	return test_bit(BH_Lock, &bh->b_state);
}

static inline int buffer_req(struct buffer_head * bh)
{
	return test_bit(BH_Req, &bh->b_state);
}

static inline int buffer_touched(struct buffer_head * bh)
{
	return test_bit(BH_Touched, &bh->b_state);
}

static inline int buffer_has_aged(struct buffer_head * bh)
{
	return test_bit(BH_Has_aged, &bh->b_state);
}

static inline int buffer_protected(struct buffer_head * bh)
{
	return test_bit(BH_Protected, &bh->b_state);
}

#include <linux/pipe_fs_i.h>
#include <linux/minix_fs_i.h>
#include <linux/ext_fs_i.h>
#include <linux/ext2_fs_i.h>
#include <linux/hpfs_fs_i.h>
#include <linux/msdos_fs_i.h>
#include <linux/umsdos_fs_i.h>
#include <linux/iso_fs_i.h>
#include <linux/nfs_fs_i.h>
#include <linux/xia_fs_i.h>
#include <linux/sysv_fs_i.h>
#include <linux/affs_fs_i.h>
#include <linux/ufs_fs_i.h>
#include <linux/romfs_fs_i.h>

/*
 * Attribute flags.  These should be or-ed together to figure out what
 * has been changed!
 */
#define ATTR_MODE	1
#define ATTR_UID	2
#define ATTR_GID	4
#define ATTR_SIZE	8
#define ATTR_ATIME	16
#define ATTR_MTIME	32
#define ATTR_CTIME	64
#define ATTR_ATIME_SET	128
#define ATTR_MTIME_SET	256
#define ATTR_FORCE	512	/* Not a change, but a change it */

/*
 * This is the Inode Attributes structure, used for notify_change().  It
 * uses the above definitions as flags, to know which values have changed.
 * Also, in this manner, a Filesystem can look at only the values it cares
 * about.  Basically, these are the attributes that the VFS layer can
 * request to change from the FS layer.
 *
 * Derek Atkins <[e-mail]> 94-10-20
 */
struct iattr {
	unsigned int	ia_valid;
	umode_t		ia_mode;
	uid_t		ia_uid;
	gid_t		ia_gid;
	off_t		ia_size;
	time_t		ia_atime;
	time_t		ia_mtime;
	time_t		ia_ctime;
};

#include <linux/quota.h>

struct vm_area_struct;

struct inode {
	kdev_t		i_dev;
	unsigned long	i_ino;
	umode_t		i_mode;
	nlink_t		i_nlink;
	uid_t		i_uid;
	gid_t		i_gid;
	kdev_t		i_rdev;
	off_t		i_size;
	time_t		i_atime;
	time_t		i_mtime;
	time_t		i_ctime;
	unsigned long	i_blksize;
	unsigned long	i_blocks;
	unsigned long	i_version;
	unsigned long	i_nrpages;
	struct semaphore i_sem;
	struct inode_operations *i_op;
	struct super_block *i_sb;
	struct wait_queue *i_wait;
	struct file_lock *i_flock;
#ifndef NO_MM
	struct vm_area_struct *i_mmap;
#endif /* !NO_MM */
	struct page *i_pages;
	struct dquot *i_dquot[MAXQUOTAS];
	struct inode *i_next, *i_prev;
	struct inode *i_hash_next, *i_hash_prev;
	struct inode *i_bound_to, *i_bound_by;
	struct inode *i_mount;
	unsigned short i_count;
	unsigned short i_flags;
	unsigned char i_lock;
	unsigned char i_dirt;
	unsigned char i_pipe;
	unsigned char i_sock;
	unsigned char i_seek;
	unsigned char i_update;
	unsigned char i_condemned;
	unsigned short i_writecount;
	union {
		struct pipe_inode_info pipe_i;
		struct minix_inode_info minix_i;
		struct ext_inode_info ext_i;
		struct ext2_inode_info ext2_i;
		struct hpfs_inode_info hpfs_i;
		struct msdos_inode_info msdos_i;
		struct umsdos_inode_info umsdos_i;
		struct iso_inode_info isofs_i;
		struct nfs_inode_info nfs_i;
		struct xiafs_inode_info xiafs_i;
		struct sysv_inode_info sysv_i;
		struct affs_inode_info affs_i;
		struct ufs_inode_info ufs_i;
		struct romfs_inode_info romfs_i;
		struct socket socket_i;
		void * generic_ip;
	} u;
};

struct fown_struct {
	int pid;		/* pid or -pgrp where SIGIO should be sent */
	uid_t uid, euid;	/* uid/euid of process setting the owner */
};

struct file {
	mode_t f_mode;
	loff_t f_pos;
	unsigned short f_flags;
	unsigned short f_count;
	unsigned long f_reada, f_ramax, f_raend, f_ralen, f_rawin;
	struct file *f_next, *f_prev;
	struct fown_struct f_owner;
	struct inode * f_inode;
	struct file_operations * f_op;
	unsigned long f_version;
	void *private_data;	/* needed for tty driver, and maybe others */
};

#define FL_POSIX	1
#define FL_FLOCK	2
#define FL_BROKEN	4	/* broken flock() emulation */
#define FL_ACCESS	8	/* for processes suspended by mandatory locking */

struct file_lock {
	struct file_lock *fl_next;	/* singly linked list for this inode  */
	struct file_lock *fl_nextlink;	/* doubly linked list of all locks */
	struct file_lock *fl_prevlink;	/* used to simplify lock removal */
	struct file_lock *fl_nextblock; /* circular list of blocked processes */