File: /usr/src/linux/include/linux/fs.h

1     #ifndef _LINUX_FS_H
2     #define _LINUX_FS_H
3     
4     /*
5      * This file has definitions for some important file table
6      * structures etc.
7      */
8     
9     #include <linux/config.h>
10     #include <linux/linkage.h>
11     #include <linux/limits.h>
12     #include <linux/wait.h>
13     #include <linux/types.h>
14     #include <linux/vfs.h>
15     #include <linux/net.h>
16     #include <linux/kdev_t.h>
17     #include <linux/ioctl.h>
18     #include <linux/list.h>
19     #include <linux/dcache.h>
20     #include <linux/stat.h>
21     #include <linux/cache.h>
22     #include <linux/stddef.h>
23     #include <linux/string.h>
24     
25     #include <asm/atomic.h>
26     #include <asm/bitops.h>
27     
28     struct poll_table_struct;
29     
30     
31     /*
32      * It's silly to have NR_OPEN bigger than NR_FILE, but you can change
33      * the file limit at runtime and only root can increase the per-process
34      * nr_file rlimit, so it's safe to set up a ridiculously high absolute
35      * upper limit on files-per-process.
36      *
37      * Some programs (notably those using select()) may have to be 
38      * recompiled to take full advantage of the new limits..  
39      */
40     
41     /* Fixed constants first: */
42     #undef NR_OPEN
43     #define NR_OPEN (1024*1024)	/* Absolute upper limit on fd num */
44     #define INR_OPEN 1024		/* Initial setting for nfile rlimits */
45     
46     #define BLOCK_SIZE_BITS 10
47     #define BLOCK_SIZE (1<<BLOCK_SIZE_BITS)
48     
49     /* buffer header fixed size for the blkdev I/O through pagecache */
50     #define BUFFERED_BLOCKSIZE_BITS 10
51     #define BUFFERED_BLOCKSIZE (1 << BUFFERED_BLOCKSIZE_BITS)
52     
53     /* And dynamically-tunable limits and defaults: */
54     struct files_stat_struct {
55     	int nr_files;		/* read only */
56     	int nr_free_files;	/* read only */
57     	int max_files;		/* tunable */
58     };
59     extern struct files_stat_struct files_stat;
60     
61     struct inodes_stat_t {
62     	int nr_inodes;
63     	int nr_unused;
64     	int dummy[5];
65     };
66     extern struct inodes_stat_t inodes_stat;
67     
68     extern int leases_enable, dir_notify_enable, lease_break_time;
69     
70     #define NR_FILE  8192	/* this can well be larger on a larger system */
71     #define NR_RESERVED_FILES 10 /* reserved for root */
72     #define NR_SUPER 256
73     
74     #define MAY_EXEC 1
75     #define MAY_WRITE 2
76     #define MAY_READ 4
77     
78     #define FMODE_READ 1
79     #define FMODE_WRITE 2
80     
81     #define READ 0
82     #define WRITE 1
83     #define READA 2		/* read-ahead  - don't block if no resources */
84     #define SPECIAL 4	/* For non-blockdevice requests in request queue */
85     
86     #define SEL_IN		1
87     #define SEL_OUT		2
88     #define SEL_EX		4
89     
90     /* public flags for file_system_type */
91     #define FS_REQUIRES_DEV 1 
92     #define FS_NO_DCACHE	2 /* Only dcache the necessary things. */
93     #define FS_NO_PRELIM	4 /* prevent preloading of dentries, even if
94     			   * FS_NO_DCACHE is not set.
95     			   */
96     #define FS_SINGLE	8 /* Filesystem that can have only one superblock */
97     #define FS_NOMOUNT	16 /* Never mount from userland */
98     #define FS_LITTER	32 /* Keeps the tree in dcache */
99     #define FS_ODD_RENAME	32768	/* Temporary stuff; will go away as soon
100     				  * as nfs_rename() will be cleaned up
101     				  */
102     /*
103      * These are the fs-independent mount-flags: up to 32 flags are supported
104      */
105     #define MS_RDONLY	 1	/* Mount read-only */
106     #define MS_NOSUID	 2	/* Ignore suid and sgid bits */
107     #define MS_NODEV	 4	/* Disallow access to device special files */
108     #define MS_NOEXEC	 8	/* Disallow program execution */
109     #define MS_SYNCHRONOUS	16	/* Writes are synced at once */
110     #define MS_REMOUNT	32	/* Alter flags of a mounted FS */
111     #define MS_MANDLOCK	64	/* Allow mandatory locks on an FS */
112     #define MS_NOATIME	1024	/* Do not update access times. */
113     #define MS_NODIRATIME	2048	/* Do not update directory access times */
114     #define MS_BIND		4096
115     #define MS_NOUSER	(1<<31)
116     
117     /*
118      * Superblock flags that can be altered by MS_REMOUNT
119      */
120     #define MS_RMT_MASK	(MS_RDONLY|MS_SYNCHRONOUS|MS_MANDLOCK|MS_NOATIME|\
121     			 MS_NODIRATIME)
122     
123     /*
124      * Old magic mount flag and mask
125      */
126     #define MS_MGC_VAL 0xC0ED0000
127     #define MS_MGC_MSK 0xffff0000
128     
129     /* Inode flags - they have nothing to superblock flags now */
130     
131     #define S_SYNC		1	/* Writes are synced at once */
132     #define S_NOATIME	2	/* Do not update access times */
133     #define S_QUOTA		4	/* Quota initialized for file */
134     #define S_APPEND	8	/* Append-only file */
135     #define S_IMMUTABLE	16	/* Immutable file */
136     #define S_DEAD		32	/* removed, but still open directory */
137     #define S_NOQUOTA	64	/* Inode is not counted to quota */
138     
139     /*
140      * Note that nosuid etc flags are inode-specific: setting some file-system
141      * flags just means all the inodes inherit those flags by default. It might be
142      * possible to override it selectively if you really wanted to with some
143      * ioctl() that is not currently implemented.
144      *
145      * Exception: MS_RDONLY is always applied to the entire file system.
146      *
147      * Unfortunately, it is possible to change a filesystems flags with it mounted
148      * with files in use.  This means that all of the inodes will not have their
149      * i_flags updated.  Hence, i_flags no longer inherit the superblock mount
150      * flags, so these have to be checked separately. -- rmk@arm.uk.linux.org
151      */
152     #define __IS_FLG(inode,flg) ((inode)->i_sb->s_flags & (flg))
153     
154     #define IS_RDONLY(inode) ((inode)->i_sb->s_flags & MS_RDONLY)
155     #define IS_SYNC(inode)		(__IS_FLG(inode, MS_SYNCHRONOUS) || ((inode)->i_flags & S_SYNC))
156     #define IS_MANDLOCK(inode)	__IS_FLG(inode, MS_MANDLOCK)
157     
158     #define IS_QUOTAINIT(inode)	((inode)->i_flags & S_QUOTA)
159     #define IS_NOQUOTA(inode)	((inode)->i_flags & S_NOQUOTA)
160     #define IS_APPEND(inode)	((inode)->i_flags & S_APPEND)
161     #define IS_IMMUTABLE(inode)	((inode)->i_flags & S_IMMUTABLE)
162     #define IS_NOATIME(inode)	(__IS_FLG(inode, MS_NOATIME) || ((inode)->i_flags & S_NOATIME))
163     #define IS_NODIRATIME(inode)	__IS_FLG(inode, MS_NODIRATIME)
164     
165     #define IS_DEADDIR(inode)	((inode)->i_flags & S_DEAD)
166     
167     /* the read-only stuff doesn't really belong here, but any other place is
168        probably as bad and I don't want to create yet another include file. */
169     
170     #define BLKROSET   _IO(0x12,93)	/* set device read-only (0 = read-write) */
171     #define BLKROGET   _IO(0x12,94)	/* get read-only status (0 = read_write) */
172     #define BLKRRPART  _IO(0x12,95)	/* re-read partition table */
173     #define BLKGETSIZE _IO(0x12,96)	/* return device size /512 (long *arg) */
174     #define BLKFLSBUF  _IO(0x12,97)	/* flush buffer cache */
175     #define BLKRASET   _IO(0x12,98)	/* Set read ahead for block device */
176     #define BLKRAGET   _IO(0x12,99)	/* get current read ahead setting */
177     #define BLKFRASET  _IO(0x12,100)/* set filesystem (mm/filemap.c) read-ahead */
178     #define BLKFRAGET  _IO(0x12,101)/* get filesystem (mm/filemap.c) read-ahead */
179     #define BLKSECTSET _IO(0x12,102)/* set max sectors per request (ll_rw_blk.c) */
180     #define BLKSECTGET _IO(0x12,103)/* get max sectors per request (ll_rw_blk.c) */
181     #define BLKSSZGET  _IO(0x12,104)/* get block device sector size */
182     #if 0
183     #define BLKPG      _IO(0x12,105)/* See blkpg.h */
184     #define BLKELVGET  _IOR(0x12,106,sizeof(blkelv_ioctl_arg_t))/* elevator get */
185     #define BLKELVSET  _IOW(0x12,107,sizeof(blkelv_ioctl_arg_t))/* elevator set */
186     /* This was here just to show that the number is taken -
187        probably all these _IO(0x12,*) ioctls should be moved to blkpg.h. */
188     #endif
189     /* A jump here: 108-111 have been used for various private purposes. */
190     #define BLKBSZGET  _IOR(0x12,112,sizeof(int))
191     #define BLKBSZSET  _IOW(0x12,113,sizeof(int))
192     #define BLKGETSIZE64 _IOR(0x12,114,sizeof(u64))	/* return device size in bytes (u64 *arg) */
193     
194     #define BMAP_IOCTL 1		/* obsolete - kept for compatibility */
195     #define FIBMAP	   _IO(0x00,1)	/* bmap access */
196     #define FIGETBSZ   _IO(0x00,2)	/* get the block size used for bmap */
197     
198     #ifdef __KERNEL__
199     
200     #include <asm/semaphore.h>
201     #include <asm/byteorder.h>
202     
203     extern void update_atime (struct inode *);
204     #define UPDATE_ATIME(inode) update_atime (inode)
205     
206     extern void buffer_init(unsigned long);
207     extern void inode_init(unsigned long);
208     extern void mnt_init(unsigned long);
209     
210     /* bh state bits */
211     enum bh_state_bits {
212     	BH_Uptodate,	/* 1 if the buffer contains valid data */
213     	BH_Dirty,	/* 1 if the buffer is dirty */
214     	BH_Lock,	/* 1 if the buffer is locked */
215     	BH_Req,		/* 0 if the buffer has been invalidated */
216     	BH_Mapped,	/* 1 if the buffer has a disk mapping */
217     	BH_New,		/* 1 if the buffer is new and not yet written out */
218     	BH_Async,	/* 1 if the buffer is under end_buffer_io_async I/O */
219     	BH_Wait_IO,	/* 1 if we should throttle on this buffer */
220     
221     	BH_PrivateStart,/* not a state bit, but the first bit available
222     			 * for private allocation by other entities
223     			 */
224     };
225     
226     /*
227      * Try to keep the most commonly used fields in single cache lines (16
228      * bytes) to improve performance.  This ordering should be
229      * particularly beneficial on 32-bit processors.
230      * 
231      * We use the first 16 bytes for the data which is used in searches
232      * over the block hash lists (ie. getblk() and friends).
233      * 
234      * The second 16 bytes we use for lru buffer scans, as used by
235      * sync_buffers() and refill_freelist().  -- sct
236      */
237     struct buffer_head {
238     	/* First cache line: */
239     	struct buffer_head *b_next;	/* Hash queue list */
240     	unsigned long b_blocknr;	/* block number */
241     	unsigned short b_size;		/* block size */
242     	unsigned short b_list;		/* List that this buffer appears */
243     	kdev_t b_dev;			/* device (B_FREE = free) */
244     
245     	atomic_t b_count;		/* users using this block */
246     	kdev_t b_rdev;			/* Real device */
247     	unsigned long b_state;		/* buffer state bitmap (see above) */
248     	unsigned long b_flushtime;	/* Time when (dirty) buffer should be written */
249     
250     	struct buffer_head *b_next_free;/* lru/free list linkage */
251     	struct buffer_head *b_prev_free;/* doubly linked list of buffers */
252     	struct buffer_head *b_this_page;/* circular list of buffers in one page */
253     	struct buffer_head *b_reqnext;	/* request queue */
254     
255     	struct buffer_head **b_pprev;	/* doubly linked list of hash-queue */
256     	char * b_data;			/* pointer to data block */
257     	struct page *b_page;		/* the page this bh is mapped to */
258     	void (*b_end_io)(struct buffer_head *bh, int uptodate); /* I/O completion */
259      	void *b_private;		/* reserved for b_end_io */
260     
261     	unsigned long b_rsector;	/* Real buffer location on disk */
262     	wait_queue_head_t b_wait;
263     
264     	struct inode *	     b_inode;
265     	struct list_head     b_inode_buffers;	/* doubly linked list of inode dirty buffers */
266     };
267     
268     typedef void (bh_end_io_t)(struct buffer_head *bh, int uptodate);
269     void init_buffer(struct buffer_head *, bh_end_io_t *, void *);
270     
271     #define __buffer_state(bh, state)	(((bh)->b_state & (1UL << BH_##state)) != 0)
272     
273     #define buffer_uptodate(bh)	__buffer_state(bh,Uptodate)
274     #define buffer_dirty(bh)	__buffer_state(bh,Dirty)
275     #define buffer_locked(bh)	__buffer_state(bh,Lock)
276     #define buffer_req(bh)		__buffer_state(bh,Req)
277     #define buffer_mapped(bh)	__buffer_state(bh,Mapped)
278     #define buffer_new(bh)		__buffer_state(bh,New)
279     #define buffer_async(bh)	__buffer_state(bh,Async)
280     
281     #define bh_offset(bh)		((unsigned long)(bh)->b_data & ~PAGE_MASK)
282     
283     extern void set_bh_page(struct buffer_head *bh, struct page *page, unsigned long offset);
284     
285     #define touch_buffer(bh)	SetPageReferenced(bh->b_page)
286     
287     
288     #include <linux/pipe_fs_i.h>
289     #include <linux/minix_fs_i.h>
290     #include <linux/ext2_fs_i.h>
291     #include <linux/hpfs_fs_i.h>
292     #include <linux/ntfs_fs_i.h>
293     #include <linux/msdos_fs_i.h>
294     #include <linux/umsdos_fs_i.h>
295     #include <linux/iso_fs_i.h>
296     #include <linux/nfs_fs_i.h>
297     #include <linux/sysv_fs_i.h>
298     #include <linux/affs_fs_i.h>
299     #include <linux/ufs_fs_i.h>
300     #include <linux/efs_fs_i.h>
301     #include <linux/coda_fs_i.h>
302     #include <linux/romfs_fs_i.h>
303     #include <linux/shmem_fs.h>
304     #include <linux/smb_fs_i.h>
305     #include <linux/hfs_fs_i.h>
306     #include <linux/adfs_fs_i.h>
307     #include <linux/qnx4_fs_i.h>
308     #include <linux/reiserfs_fs_i.h>
309     #include <linux/bfs_fs_i.h>
310     #include <linux/udf_fs_i.h>
311     #include <linux/ncp_fs_i.h>
312     #include <linux/proc_fs_i.h>
313     #include <linux/usbdev_fs_i.h>
314     #include <linux/jffs2_fs_i.h>
315     #include <linux/cramfs_fs_sb.h>
316     
317     /*
318      * Attribute flags.  These should be or-ed together to figure out what
319      * has been changed!
320      */
321     #define ATTR_MODE	1
322     #define ATTR_UID	2
323     #define ATTR_GID	4
324     #define ATTR_SIZE	8
325     #define ATTR_ATIME	16
326     #define ATTR_MTIME	32
327     #define ATTR_CTIME	64
328     #define ATTR_ATIME_SET	128
329     #define ATTR_MTIME_SET	256
330     #define ATTR_FORCE	512	/* Not a change, but a change it */
331     #define ATTR_ATTR_FLAG	1024
332     
333     /*
334      * This is the Inode Attributes structure, used for notify_change().  It
335      * uses the above definitions as flags, to know which values have changed.
336      * Also, in this manner, a Filesystem can look at only the values it cares
337      * about.  Basically, these are the attributes that the VFS layer can
338      * request to change from the FS layer.
339      *
340      * Derek Atkins <warlord@MIT.EDU> 94-10-20
341      */
342     struct iattr {
343     	unsigned int	ia_valid;
344     	umode_t		ia_mode;
345     	uid_t		ia_uid;
346     	gid_t		ia_gid;
347     	loff_t		ia_size;
348     	time_t		ia_atime;
349     	time_t		ia_mtime;
350     	time_t		ia_ctime;
351     	unsigned int	ia_attr_flags;
352     };
353     
354     /*
355      * This is the inode attributes flag definitions
356      */
357     #define ATTR_FLAG_SYNCRONOUS	1 	/* Syncronous write */
358     #define ATTR_FLAG_NOATIME	2 	/* Don't update atime */
359     #define ATTR_FLAG_APPEND	4 	/* Append-only file */
360     #define ATTR_FLAG_IMMUTABLE	8 	/* Immutable file */
361     #define ATTR_FLAG_NODIRATIME	16 	/* Don't update atime for directory */
362     
363     /*
364      * Includes for diskquotas and mount structures.
365      */
366     #include <linux/quota.h>
367     #include <linux/mount.h>
368     
369     /*
370      * oh the beauties of C type declarations.
371      */
372     struct page;
373     struct address_space;
374     struct kiobuf;
375     
376     struct address_space_operations {
377     	int (*writepage)(struct page *);
378     	int (*readpage)(struct file *, struct page *);
379     	int (*sync_page)(struct page *);
380     	int (*prepare_write)(struct file *, struct page *, unsigned, unsigned);
381     	int (*commit_write)(struct file *, struct page *, unsigned, unsigned);
382     	/* Unfortunately this kludge is needed for FIBMAP. Don't use it */
383     	int (*bmap)(struct address_space *, long);
384     #define KERNEL_HAS_O_DIRECT /* this is for modules out of the kernel */
385     	int (*direct_IO)(int, struct inode *, struct kiobuf *, unsigned long, int);
386     };
387     
388     struct address_space {
389     	struct list_head	clean_pages;	/* list of clean pages */
390     	struct list_head	dirty_pages;	/* list of dirty pages */
391     	struct list_head	locked_pages;	/* list of locked pages */
392     	unsigned long		nrpages;	/* number of total pages */
393     	struct address_space_operations *a_ops;	/* methods */
394     	struct inode		*host;		/* owner: inode, block_device */
395     	struct vm_area_struct	*i_mmap;	/* list of private mappings */
396     	struct vm_area_struct	*i_mmap_shared; /* list of shared mappings */
397     	spinlock_t		i_shared_lock;  /* and spinlock protecting it */
398     	int			gfp_mask;	/* how to allocate the pages */
399     };
400     
401     struct char_device {
402     	struct list_head	hash;
403     	atomic_t		count;
404     	dev_t			dev;
405     	atomic_t		openers;
406     	struct semaphore	sem;
407     };
408     
409     struct block_device {
410     	struct list_head	bd_hash;
411     	atomic_t		bd_count;
412     	struct inode *		bd_inode;
413     	dev_t			bd_dev;  /* not a kdev_t - it's a search key */
414     	int			bd_openers;
415     	const struct block_device_operations *bd_op;
416     	struct semaphore	bd_sem;	/* open/close mutex */
417     	struct list_head	bd_inodes;
418     };
419     
420     struct inode {
421     	struct list_head	i_hash;
422     	struct list_head	i_list;
423     	struct list_head	i_dentry;
424     	
425     	struct list_head	i_dirty_buffers;
426     	struct list_head	i_dirty_data_buffers;
427     
428     	unsigned long		i_ino;
429     	atomic_t		i_count;
430     	kdev_t			i_dev;
431     	umode_t			i_mode;
432     	nlink_t			i_nlink;
433     	uid_t			i_uid;
434     	gid_t			i_gid;
435     	kdev_t			i_rdev;
436     	loff_t			i_size;
437     	time_t			i_atime;
438     	time_t			i_mtime;
439     	time_t			i_ctime;
440     	unsigned long		i_blksize;
441     	unsigned long		i_blocks;
442     	unsigned long		i_version;
443     	struct semaphore	i_sem;
444     	struct semaphore	i_zombie;
445     	struct inode_operations	*i_op;
446     	struct file_operations	*i_fop;	/* former ->i_op->default_file_ops */
447     	struct super_block	*i_sb;
448     	wait_queue_head_t	i_wait;
449     	struct file_lock	*i_flock;
450     	struct address_space	*i_mapping;
451     	struct address_space	i_data;
452     	struct dquot		*i_dquot[MAXQUOTAS];
453     	/* These three should probably be a union */
454     	struct list_head	i_devices;
455     	struct pipe_inode_info	*i_pipe;
456     	struct block_device	*i_bdev;
457     	struct char_device	*i_cdev;
458     
459     	unsigned long		i_dnotify_mask; /* Directory notify events */
460     	struct dnotify_struct	*i_dnotify; /* for directory notifications */
461     
462     	unsigned long		i_state;
463     
464     	unsigned int		i_flags;
465     	unsigned char		i_sock;
466     
467     	atomic_t		i_writecount;
468     	unsigned int		i_attr_flags;
469     	__u32			i_generation;
470     	union {
471     		struct minix_inode_info		minix_i;
472     		struct ext2_inode_info		ext2_i;
473     		struct hpfs_inode_info		hpfs_i;
474     		struct ntfs_inode_info		ntfs_i;
475     		struct msdos_inode_info		msdos_i;
476     		struct umsdos_inode_info	umsdos_i;
477     		struct iso_inode_info		isofs_i;
478     		struct nfs_inode_info		nfs_i;
479     		struct sysv_inode_info		sysv_i;
480     		struct affs_inode_info		affs_i;
481     		struct ufs_inode_info		ufs_i;
482     		struct efs_inode_info		efs_i;
483     		struct romfs_inode_info		romfs_i;
484     		struct shmem_inode_info		shmem_i;
485     		struct coda_inode_info		coda_i;
486     		struct smb_inode_info		smbfs_i;
487     		struct hfs_inode_info		hfs_i;
488     		struct adfs_inode_info		adfs_i;
489     		struct qnx4_inode_info		qnx4_i;
490     		struct reiserfs_inode_info	reiserfs_i;
491     		struct bfs_inode_info		bfs_i;
492     		struct udf_inode_info		udf_i;
493     		struct ncp_inode_info		ncpfs_i;
494     		struct proc_inode_info		proc_i;
495     		struct socket			socket_i;
496     		struct usbdev_inode_info        usbdev_i;
497     		struct jffs2_inode_info		jffs2_i;
498     		void				*generic_ip;
499     	} u;
500     };
501     
502     struct fown_struct {
503     	int pid;		/* pid or -pgrp where SIGIO should be sent */
504     	uid_t uid, euid;	/* uid/euid of process setting the owner */
505     	int signum;		/* posix.1b rt signal to be delivered on IO */
506     };
507     
508     struct file {
509     	struct list_head	f_list;
510     	struct dentry		*f_dentry;
511     	struct vfsmount         *f_vfsmnt;
512     	struct file_operations	*f_op;
513     	atomic_t		f_count;
514     	unsigned int 		f_flags;
515     	mode_t			f_mode;
516     	loff_t			f_pos;
517     	unsigned long 		f_reada, f_ramax, f_raend, f_ralen, f_rawin;
518     	struct fown_struct	f_owner;
519     	unsigned int		f_uid, f_gid;
520     	int			f_error;
521     
522     	unsigned long		f_version;
523     
524     	/* needed for tty driver, and maybe others */
525     	void			*private_data;
526     
527     	/* preallocated helper kiobuf to speedup O_DIRECT */
528     	struct kiobuf		*f_iobuf;
529     	long			f_iobuf_lock;
530     };
531     extern spinlock_t files_lock;
532     #define file_list_lock() spin_lock(&files_lock);
533     #define file_list_unlock() spin_unlock(&files_lock);
534     
535     #define get_file(x)	atomic_inc(&(x)->f_count)
536     #define file_count(x)	atomic_read(&(x)->f_count)
537     
538     extern int init_private_file(struct file *, struct dentry *, int);
539     
540     #define	MAX_NON_LFS	((1UL<<31) - 1)
541     
542     #define FL_POSIX	1
543     #define FL_FLOCK	2
544     #define FL_BROKEN	4	/* broken flock() emulation */
545     #define FL_ACCESS	8	/* for processes suspended by mandatory locking */
546     #define FL_LOCKD	16	/* lock held by rpc.lockd */
547     #define FL_LEASE	32	/* lease held on this file */
548     
549     /*
550      * The POSIX file lock owner is determined by
551      * the "struct files_struct" in the thread group
552      * (or NULL for no owner - BSD locks).
553      *
554      * Lockd stuffs a "host" pointer into this.
555      */
556     typedef struct files_struct *fl_owner_t;
557     
558     struct file_lock {
559     	struct file_lock *fl_next;	/* singly linked list for this inode  */
560     	struct list_head fl_link;	/* doubly linked list of all locks */
561     	struct list_head fl_block;	/* circular list of blocked processes */
562     	fl_owner_t fl_owner;
563     	unsigned int fl_pid;
564     	wait_queue_head_t fl_wait;
565     	struct file *fl_file;
566     	unsigned char fl_flags;
567     	unsigned char fl_type;
568     	loff_t fl_start;
569     	loff_t fl_end;
570     
571     	void (*fl_notify)(struct file_lock *);	/* unblock callback */
572     	void (*fl_insert)(struct file_lock *);	/* lock insertion callback */
573     	void (*fl_remove)(struct file_lock *);	/* lock removal callback */
574     
575     	struct fasync_struct *	fl_fasync; /* for lease break notifications */
576     
577     	union {
578     		struct nfs_lock_info	nfs_fl;
579     	} fl_u;
580     };
581     
582     /* The following constant reflects the upper bound of the file/locking space */
583     #ifndef OFFSET_MAX
584     #define INT_LIMIT(x)	(~((x)1 << (sizeof(x)*8 - 1)))
585     #define OFFSET_MAX	INT_LIMIT(loff_t)
586     #define OFFT_OFFSET_MAX	INT_LIMIT(off_t)
587     #endif
588     
589     extern struct list_head file_lock_list;
590     
591     #include <linux/fcntl.h>
592     
593     extern int fcntl_getlk(unsigned int, struct flock *);
594     extern int fcntl_setlk(unsigned int, unsigned int, struct flock *);
595     
596     extern int fcntl_getlk64(unsigned int, struct flock64 *);
597     extern int fcntl_setlk64(unsigned int, unsigned int, struct flock64 *);
598     
599     /* fs/locks.c */
600     extern void locks_init_lock(struct file_lock *);
601     extern void locks_copy_lock(struct file_lock *, struct file_lock *);
602     extern void locks_remove_posix(struct file *, fl_owner_t);
603     extern void locks_remove_flock(struct file *);
604     extern struct file_lock *posix_test_lock(struct file *, struct file_lock *);
605     extern int posix_lock_file(struct file *, struct file_lock *, unsigned int);
606     extern void posix_block_lock(struct file_lock *, struct file_lock *);
607     extern void posix_unblock_lock(struct file_lock *);
608     extern int __get_lease(struct inode *inode, unsigned int flags);
609     extern time_t lease_get_mtime(struct inode *);
610     extern int lock_may_read(struct inode *, loff_t start, unsigned long count);
611     extern int lock_may_write(struct inode *, loff_t start, unsigned long count);
612     
613     struct fasync_struct {
614     	int	magic;
615     	int	fa_fd;
616     	struct	fasync_struct	*fa_next; /* singly linked list */
617     	struct	file 		*fa_file;
618     };
619     
620     #define FASYNC_MAGIC 0x4601
621     
622     /* SMP safe fasync helpers: */
623     extern int fasync_helper(int, struct file *, int, struct fasync_struct **);
624     /* can be called from interrupts */
625     extern void kill_fasync(struct fasync_struct **, int, int);
626     /* only for net: no internal synchronization */
627     extern void __kill_fasync(struct fasync_struct *, int, int);
628     
629     struct nameidata {
630     	struct dentry *dentry;
631     	struct vfsmount *mnt;
632     	struct qstr last;
633     	unsigned int flags;
634     	int last_type;
635     };
636     
637     #define DQUOT_USR_ENABLED	0x01		/* User diskquotas enabled */
638     #define DQUOT_GRP_ENABLED	0x02		/* Group diskquotas enabled */
639     
640     struct quota_mount_options
641     {
642     	unsigned int flags;			/* Flags for diskquotas on this device */
643     	struct semaphore dqio_sem;		/* lock device while I/O in progress */
644     	struct semaphore dqoff_sem;		/* serialize quota_off() and quota_on() on device */
645     	struct file *files[MAXQUOTAS];		/* fp's to quotafiles */
646     	time_t inode_expire[MAXQUOTAS];		/* expiretime for inode-quota */
647     	time_t block_expire[MAXQUOTAS];		/* expiretime for block-quota */
648     	char rsquash[MAXQUOTAS];		/* for quotas threat root as any other user */
649     };
650     
651     /*
652      *	Umount options
653      */
654     
655     #define MNT_FORCE	0x00000001	/* Attempt to forcibily umount */
656     
657     #include <linux/minix_fs_sb.h>
658     #include <linux/ext2_fs_sb.h>
659     #include <linux/hpfs_fs_sb.h>
660     #include <linux/ntfs_fs_sb.h>
661     #include <linux/msdos_fs_sb.h>
662     #include <linux/iso_fs_sb.h>
663     #include <linux/nfs_fs_sb.h>
664     #include <linux/sysv_fs_sb.h>
665     #include <linux/affs_fs_sb.h>
666     #include <linux/ufs_fs_sb.h>
667     #include <linux/efs_fs_sb.h>
668     #include <linux/romfs_fs_sb.h>
669     #include <linux/smb_fs_sb.h>
670     #include <linux/hfs_fs_sb.h>
671     #include <linux/adfs_fs_sb.h>
672     #include <linux/qnx4_fs_sb.h>
673     #include <linux/reiserfs_fs_sb.h>
674     #include <linux/bfs_fs_sb.h>
675     #include <linux/udf_fs_sb.h>
676     #include <linux/ncp_fs_sb.h>
677     #include <linux/usbdev_fs_sb.h>
678     #include <linux/cramfs_fs_sb.h>
679     #include <linux/jffs2_fs_sb.h>
680     
681     extern struct list_head super_blocks;
682     extern spinlock_t sb_lock;
683     
684     #define sb_entry(list)	list_entry((list), struct super_block, s_list)
685     #define S_BIAS (1<<30)
686     struct super_block {
687     	struct list_head	s_list;		/* Keep this first */
688     	kdev_t			s_dev;
689     	unsigned long		s_blocksize;
690     	unsigned char		s_blocksize_bits;
691     	unsigned char		s_dirt;
692     	unsigned long long	s_maxbytes;	/* Max file size */
693     	struct file_system_type	*s_type;
694     	struct super_operations	*s_op;
695     	struct dquot_operations	*dq_op;
696     	unsigned long		s_flags;
697     	unsigned long		s_magic;
698     	struct dentry		*s_root;
699     	struct rw_semaphore	s_umount;
700     	struct semaphore	s_lock;
701     	int			s_count;
702     	atomic_t		s_active;
703     
704     	struct list_head	s_dirty;	/* dirty inodes */
705     	struct list_head	s_locked_inodes;/* inodes being synced */
706     	struct list_head	s_files;
707     
708     	struct block_device	*s_bdev;
709     	struct list_head	s_instances;
710     	struct quota_mount_options s_dquot;	/* Diskquota specific options */
711     
712     	union {
713     		struct minix_sb_info	minix_sb;
714     		struct ext2_sb_info	ext2_sb;
715     		struct hpfs_sb_info	hpfs_sb;
716     		struct ntfs_sb_info	ntfs_sb;
717     		struct msdos_sb_info	msdos_sb;
718     		struct isofs_sb_info	isofs_sb;
719     		struct nfs_sb_info	nfs_sb;
720     		struct sysv_sb_info	sysv_sb;
721     		struct affs_sb_info	affs_sb;
722     		struct ufs_sb_info	ufs_sb;
723     		struct efs_sb_info	efs_sb;
724     		struct shmem_sb_info	shmem_sb;
725     		struct romfs_sb_info	romfs_sb;
726     		struct smb_sb_info	smbfs_sb;
727     		struct hfs_sb_info	hfs_sb;
728     		struct adfs_sb_info	adfs_sb;
729     		struct qnx4_sb_info	qnx4_sb;
730     		struct reiserfs_sb_info	reiserfs_sb;
731     		struct bfs_sb_info	bfs_sb;
732     		struct udf_sb_info	udf_sb;
733     		struct ncp_sb_info	ncpfs_sb;
734     		struct usbdev_sb_info   usbdevfs_sb;
735     		struct jffs2_sb_info	jffs2_sb;
736     		struct cramfs_sb_info	cramfs_sb;
737     		void			*generic_sbp;
738     	} u;
739     	/*
740     	 * The next field is for VFS *only*. No filesystems have any business
741     	 * even looking at it. You had been warned.
742     	 */
743     	struct semaphore s_vfs_rename_sem;	/* Kludge */
744     
745     	/* The next field is used by knfsd when converting a (inode number based)
746     	 * file handle into a dentry. As it builds a path in the dcache tree from
747     	 * the bottom up, there may for a time be a subpath of dentrys which is not
748     	 * connected to the main tree.  This semaphore ensure that there is only ever
749     	 * one such free path per filesystem.  Note that unconnected files (or other
750     	 * non-directories) are allowed, but not unconnected diretories.
751     	 */
752     	struct semaphore s_nfsd_free_path_sem;
753     };
754     
755     /*
756      * VFS helper functions..
757      */
758     extern int vfs_create(struct inode *, struct dentry *, int);
759     extern int vfs_mkdir(struct inode *, struct dentry *, int);
760     extern int vfs_mknod(struct inode *, struct dentry *, int, dev_t);
761     extern int vfs_symlink(struct inode *, struct dentry *, const char *);
762     extern int vfs_link(struct dentry *, struct inode *, struct dentry *);
763     extern int vfs_rmdir(struct inode *, struct dentry *);
764     extern int vfs_unlink(struct inode *, struct dentry *);
765     extern int vfs_rename(struct inode *, struct dentry *, struct inode *, struct dentry *);
766     
767     /*
768      * File types
769      */
770     #define DT_UNKNOWN	0
771     #define DT_FIFO		1
772     #define DT_CHR		2
773     #define DT_DIR		4
774     #define DT_BLK		6
775     #define DT_REG		8
776     #define DT_LNK		10
777     #define DT_SOCK		12
778     #define DT_WHT		14
779     
780     /*
781      * This is the "filldir" function type, used by readdir() to let
782      * the kernel specify what kind of dirent layout it wants to have.
783      * This allows the kernel to read directories into kernel space or
784      * to have different dirent layouts depending on the binary type.
785      */
786     typedef int (*filldir_t)(void *, const char *, int, loff_t, ino_t, unsigned);
787     
788     struct block_device_operations {
789     	int (*open) (struct inode *, struct file *);
790     	int (*release) (struct inode *, struct file *);
791     	int (*ioctl) (struct inode *, struct file *, unsigned, unsigned long);
792     	int (*check_media_change) (kdev_t);
793     	int (*revalidate) (kdev_t);
794     };
795     
796     /*
797      * NOTE:
798      * read, write, poll, fsync, readv, writev can be called
799      *   without the big kernel lock held in all filesystems.
800      */
801     struct file_operations {
802     	struct module *owner;
803     	loff_t (*llseek) (struct file *, loff_t, int);
804     	ssize_t (*read) (struct file *, char *, size_t, loff_t *);
805     	ssize_t (*write) (struct file *, const char *, size_t, loff_t *);
806     	int (*readdir) (struct file *, void *, filldir_t);
807     	unsigned int (*poll) (struct file *, struct poll_table_struct *);
808     	int (*ioctl) (struct inode *, struct file *, unsigned int, unsigned long);
809     	int (*mmap) (struct file *, struct vm_area_struct *);
810     	int (*open) (struct inode *, struct file *);
811     	int (*flush) (struct file *);
812     	int (*release) (struct inode *, struct file *);
813     	int (*fsync) (struct file *, struct dentry *, int datasync);
814     	int (*fasync) (int, struct file *, int);
815     	int (*lock) (struct file *, int, struct file_lock *);
816     	ssize_t (*readv) (struct file *, const struct iovec *, unsigned long, loff_t *);
817     	ssize_t (*writev) (struct file *, const struct iovec *, unsigned long, loff_t *);
818     	ssize_t (*sendpage) (struct file *, struct page *, int, size_t, loff_t *, int);
819     	unsigned long (*get_unmapped_area)(struct file *, unsigned long, unsigned long, unsigned long, unsigned long);
820     };
821     
822     struct inode_operations {
823     	int (*create) (struct inode *,struct dentry *,int);
824     	struct dentry * (*lookup) (struct inode *,struct dentry *);
825     	int (*link) (struct dentry *,struct inode *,struct dentry *);
826     	int (*unlink) (struct inode *,struct dentry *);
827     	int (*symlink) (struct inode *,struct dentry *,const char *);
828     	int (*mkdir) (struct inode *,struct dentry *,int);
829     	int (*rmdir) (struct inode *,struct dentry *);
830     	int (*mknod) (struct inode *,struct dentry *,int,int);
831     	int (*rename) (struct inode *, struct dentry *,
832     			struct inode *, struct dentry *);
833     	int (*readlink) (struct dentry *, char *,int);
834     	int (*follow_link) (struct dentry *, struct nameidata *);
835     	void (*truncate) (struct inode *);
836     	int (*permission) (struct inode *, int);
837     	int (*revalidate) (struct dentry *);
838     	int (*setattr) (struct dentry *, struct iattr *);
839     	int (*getattr) (struct dentry *, struct iattr *);
840     };
841     
842     /*
843      * NOTE: write_inode, delete_inode, clear_inode, put_inode can be called
844      * without the big kernel lock held in all filesystems.
845      */
846     struct super_operations {
847     	void (*read_inode) (struct inode *);
848       
849       	/* reiserfs kludge.  reiserfs needs 64 bits of information to
850         	** find an inode.  We are using the read_inode2 call to get
851        	** that information.  We don't like this, and are waiting on some
852        	** VFS changes for the real solution.
853        	** iget4 calls read_inode2, iff it is defined
854        	*/
855         	void (*read_inode2) (struct inode *, void *) ;
856        	void (*dirty_inode) (struct inode *);
857     	void (*write_inode) (struct inode *, int);
858     	void (*put_inode) (struct inode *);
859     	void (*delete_inode) (struct inode *);
860     	void (*put_super) (struct super_block *);
861     	void (*write_super) (struct super_block *);
862     	void (*write_super_lockfs) (struct super_block *);
863     	void (*unlockfs) (struct super_block *);
864     	int (*statfs) (struct super_block *, struct statfs *);
865     	int (*remount_fs) (struct super_block *, int *, char *);
866     	void (*clear_inode) (struct inode *);
867     	void (*umount_begin) (struct super_block *);
868     
869     	/* Following are for knfsd to interact with "interesting" filesystems
870     	 * Currently just reiserfs, but possibly FAT and others later
871     	 *
872     	 * fh_to_dentry is given a filehandle fragement with length, and a type flag
873     	 *   and must return a dentry for the referenced object or, if "parent" is
874     	 *   set, a dentry for the parent of the object.
875     	 *   If a dentry cannot be found, a "root" dentry should be created and
876     	 *   flaged as DCACHE_NFSD_DISCONNECTED. nfsd_iget is an example implementation.
877     	 *
878     	 * dentry_to_fh is given a dentry and must generate the filesys specific
879     	 *   part of the file handle.  Available length is passed in *lenp and used
880     	 *   length should be returned therein.
881     	 *   If need_parent is set, then dentry_to_fh should encode sufficient information
882     	 *   to find the (current) parent.
883     	 *   dentry_to_fh should return a 1byte "type" which will be passed back in
884     	 *   the fhtype arguement to fh_to_dentry.  Type of 0 is reserved.
885     	 *   If filesystem was exportable before the introduction of fh_to_dentry,
886     	 *   types 1 and 2 should be used is that same way as the generic code.
887     	 *   Type 255 means error.
888     	 *
889     	 * Lengths are in units of 4bytes, not bytes.
890     	 */
891     	struct dentry * (*fh_to_dentry)(struct super_block *sb, __u32 *fh, int len, int fhtype, int parent);
892     	int (*dentry_to_fh)(struct dentry *, __u32 *fh, int *lenp, int need_parent);
893     };
894     
895     /* Inode state bits.. */
896     #define I_DIRTY_SYNC		1 /* Not dirty enough for O_DATASYNC */
897     #define I_DIRTY_DATASYNC	2 /* Data-related inode changes pending */
898     #define I_DIRTY_PAGES		4 /* Data-related inode changes pending */
899     #define I_LOCK			8
900     #define I_FREEING		16
901     #define I_CLEAR			32
902     
903     #define I_DIRTY (I_DIRTY_SYNC | I_DIRTY_DATASYNC | I_DIRTY_PAGES)
904     
905     extern void __mark_inode_dirty(struct inode *, int);
906     static inline void mark_inode_dirty(struct inode *inode)
907     {
908     	__mark_inode_dirty(inode, I_DIRTY);
909     }
910     
911     static inline void mark_inode_dirty_sync(struct inode *inode)
912     {
913     	__mark_inode_dirty(inode, I_DIRTY_SYNC);
914     }
915     
916     static inline void mark_inode_dirty_pages(struct inode *inode)
917     {
918     	__mark_inode_dirty(inode, I_DIRTY_PAGES);
919     }
920     
921     struct dquot_operations {
922     	void (*initialize) (struct inode *, short);
923     	void (*drop) (struct inode *);
924     	int (*alloc_block) (const struct inode *, unsigned long, char);
925     	int (*alloc_inode) (const struct inode *, unsigned long);
926     	void (*free_block) (const struct inode *, unsigned long);
927     	void (*free_inode) (const struct inode *, unsigned long);
928     	int (*transfer) (struct dentry *, struct iattr *);
929     };
930     
931     struct file_system_type {
932     	const char *name;
933     	int fs_flags;
934     	struct super_block *(*read_super) (struct super_block *, void *, int);
935     	struct module *owner;
936     	struct file_system_type * next;
937     	struct list_head fs_supers;
938     };
939     
940     #define DECLARE_FSTYPE(var,type,read,flags) \
941     struct file_system_type var = { \
942     	name:		type, \
943     	read_super:	read, \
944     	fs_flags:	flags, \
945     	owner:		THIS_MODULE, \
946     }
947     
948     #define DECLARE_FSTYPE_DEV(var,type,read) \
949     	DECLARE_FSTYPE(var,type,read,FS_REQUIRES_DEV)
950     
951     /* Alas, no aliases. Too much hassle with bringing module.h everywhere */
952     #define fops_get(fops) \
953     	(((fops) && (fops)->owner)	\
954     		? ( try_inc_mod_count((fops)->owner) ? (fops) : NULL ) \
955     		: (fops))
956     
957     #define fops_put(fops) \
958     do {	\
959     	if ((fops) && (fops)->owner) \
960     		__MOD_DEC_USE_COUNT((fops)->owner);	\
961     } while(0)
962     
963     extern int register_filesystem(struct file_system_type *);
964     extern int unregister_filesystem(struct file_system_type *);
965     extern struct vfsmount *kern_mount(struct file_system_type *);
966     extern int may_umount(struct vfsmount *);
967     extern long do_mount(char *, char *, char *, unsigned long, void *);
968     
969     #define kern_umount mntput
970     
971     extern int vfs_statfs(struct super_block *, struct statfs *);
972     
973     /* Return value for VFS lock functions - tells locks.c to lock conventionally
974      * REALLY kosha for root NFS and nfs_lock
975      */ 
976     #define LOCK_USE_CLNT 1
977     
978     #define FLOCK_VERIFY_READ  1
979     #define FLOCK_VERIFY_WRITE 2
980     
981     extern int locks_mandatory_locked(struct inode *);
982     extern int locks_mandatory_area(int, struct inode *, struct file *, loff_t, size_t);
983     
984     /*
985      * Candidates for mandatory locking have the setgid bit set
986      * but no group execute bit -  an otherwise meaningless combination.
987      */
988     #define MANDATORY_LOCK(inode) \
989     	(IS_MANDLOCK(inode) && ((inode)->i_mode & (S_ISGID | S_IXGRP)) == S_ISGID)
990     
991     static inline int locks_verify_locked(struct inode *inode)
992     {
993     	if (MANDATORY_LOCK(inode))
994     		return locks_mandatory_locked(inode);
995     	return 0;
996     }
997     
998     static inline int locks_verify_area(int read_write, struct inode *inode,
999     				    struct file *filp, loff_t offset,
1000     				    size_t count)
1001     {
1002     	if (inode->i_flock && MANDATORY_LOCK(inode))
1003     		return locks_mandatory_area(read_write, inode, filp, offset, count);
1004     	return 0;
1005     }
1006     
1007     static inline int locks_verify_truncate(struct inode *inode,
1008     				    struct file *filp,
1009     				    loff_t size)
1010     {
1011     	if (inode->i_flock && MANDATORY_LOCK(inode))
1012     		return locks_mandatory_area(
1013     			FLOCK_VERIFY_WRITE, inode, filp,
1014     			size < inode->i_size ? size : inode->i_size,
1015     			(size < inode->i_size ? inode->i_size - size
1016     			 : size - inode->i_size)
1017     		);
1018     	return 0;
1019     }
1020     
1021     static inline int get_lease(struct inode *inode, unsigned int mode)
1022     {
1023     	if (inode->i_flock && (inode->i_flock->fl_flags & FL_LEASE))
1024     		return __get_lease(inode, mode);
1025     	return 0;
1026     }
1027     
1028     /* fs/open.c */
1029     
1030     asmlinkage long sys_open(const char *, int, int);
1031     asmlinkage long sys_close(unsigned int);	/* yes, it's really unsigned */
1032     extern int do_truncate(struct dentry *, loff_t start);
1033     
1034     extern struct file *filp_open(const char *, int, int);
1035     extern struct file * dentry_open(struct dentry *, struct vfsmount *, int);
1036     extern int filp_close(struct file *, fl_owner_t id);
1037     extern char * getname(const char *);
1038     
1039     /* fs/dcache.c */
1040     extern void vfs_caches_init(unsigned long);
1041     
1042     #define __getname()	kmem_cache_alloc(names_cachep, SLAB_KERNEL)
1043     #define putname(name)	kmem_cache_free(names_cachep, (void *)(name))
1044     
1045     enum {BDEV_FILE, BDEV_SWAP, BDEV_FS, BDEV_RAW};
1046     extern int register_blkdev(unsigned int, const char *, struct block_device_operations *);
1047     extern int unregister_blkdev(unsigned int, const char *);
1048     extern struct block_device *bdget(dev_t);
1049     extern int bd_acquire(struct inode *inode);
1050     extern void bd_forget(struct inode *inode);
1051     extern void bdput(struct block_device *);
1052     extern struct char_device *cdget(dev_t);
1053     extern void cdput(struct char_device *);
1054     extern int blkdev_open(struct inode *, struct file *);
1055     extern int blkdev_close(struct inode *, struct file *);
1056     extern struct file_operations def_blk_fops;
1057     extern struct address_space_operations def_blk_aops;
1058     extern struct file_operations def_fifo_fops;
1059     extern int ioctl_by_bdev(struct block_device *, unsigned, unsigned long);
1060     extern int blkdev_get(struct block_device *, mode_t, unsigned, int);
1061     extern int blkdev_put(struct block_device *, int);
1062     
1063     /* fs/devices.c */
1064     extern const struct block_device_operations *get_blkfops(unsigned int);
1065     extern int register_chrdev(unsigned int, const char *, struct file_operations *);
1066     extern int unregister_chrdev(unsigned int, const char *);
1067     extern int chrdev_open(struct inode *, struct file *);
1068     extern const char * bdevname(kdev_t);
1069     extern const char * cdevname(kdev_t);
1070     extern const char * kdevname(kdev_t);
1071     extern void init_special_inode(struct inode *, umode_t, int);
1072     
1073     /* Invalid inode operations -- fs/bad_inode.c */
1074     extern void make_bad_inode(struct inode *);
1075     extern int is_bad_inode(struct inode *);
1076     
1077     extern struct file_operations read_fifo_fops;
1078     extern struct file_operations write_fifo_fops;
1079     extern struct file_operations rdwr_fifo_fops;
1080     extern struct file_operations read_pipe_fops;
1081     extern struct file_operations write_pipe_fops;
1082     extern struct file_operations rdwr_pipe_fops;
1083     
1084     extern int fs_may_remount_ro(struct super_block *);
1085     
1086     extern int try_to_free_buffers(struct page *, unsigned int);
1087     extern void refile_buffer(struct buffer_head * buf);
1088     extern void end_buffer_io_sync(struct buffer_head *bh, int uptodate);
1089     
1090     /* reiserfs_writepage needs this */
1091     extern void set_buffer_async_io(struct buffer_head *bh) ;
1092     
1093     #define BUF_CLEAN	0
1094     #define BUF_LOCKED	1	/* Buffers scheduled for write */
1095     #define BUF_DIRTY	2	/* Dirty buffers, not yet scheduled for write */
1096     #define NR_LIST		3
1097     
1098     static inline void get_bh(struct buffer_head * bh)
1099     {
1100             atomic_inc(&(bh)->b_count);
1101     }
1102     
1103     static inline void put_bh(struct buffer_head *bh)
1104     {
1105             smp_mb__before_atomic_dec();
1106             atomic_dec(&bh->b_count);
1107     }
1108     
1109     /*
1110      * This is called by bh->b_end_io() handlers when I/O has completed.
1111      */
1112     static inline void mark_buffer_uptodate(struct buffer_head * bh, int on)
1113     {
1114     	if (on)
1115     		set_bit(BH_Uptodate, &bh->b_state);
1116     	else
1117     		clear_bit(BH_Uptodate, &bh->b_state);
1118     }
1119     
1120     #define atomic_set_buffer_clean(bh) test_and_clear_bit(BH_Dirty, &(bh)->b_state)
1121     
1122     static inline void __mark_buffer_clean(struct buffer_head *bh)
1123     {
1124     	refile_buffer(bh);
1125     }
1126     
1127     static inline void mark_buffer_clean(struct buffer_head * bh)
1128     {
1129     	if (atomic_set_buffer_clean(bh))
1130     		__mark_buffer_clean(bh);
1131     }
1132     
1133     extern void FASTCALL(__mark_dirty(struct buffer_head *bh));
1134     extern void FASTCALL(__mark_buffer_dirty(struct buffer_head *bh));
1135     extern void FASTCALL(mark_buffer_dirty(struct buffer_head *bh));
1136     extern void FASTCALL(buffer_insert_inode_data_queue(struct buffer_head *, struct inode *));
1137     
1138     #define atomic_set_buffer_dirty(bh) test_and_set_bit(BH_Dirty, &(bh)->b_state)
1139     
1140     static inline void mark_buffer_async(struct buffer_head * bh, int on)
1141     {
1142     	if (on)
1143     		set_bit(BH_Async, &bh->b_state);
1144     	else
1145     		clear_bit(BH_Async, &bh->b_state);
1146     }
1147     
1148     /*
1149      * If an error happens during the make_request, this function
1150      * has to be recalled. It marks the buffer as clean and not
1151      * uptodate, and it notifys the upper layer about the end
1152      * of the I/O.
1153      */
1154     static inline void buffer_IO_error(struct buffer_head * bh)
1155     {
1156     	mark_buffer_clean(bh);
1157     	/*
1158     	 * b_end_io has to clear the BH_Uptodate bitflag in the error case!
1159     	 */
1160     	bh->b_end_io(bh, 0);
1161     }
1162     
1163     extern void buffer_insert_inode_queue(struct buffer_head *, struct inode *);
1164     static inline void mark_buffer_dirty_inode(struct buffer_head *bh, struct inode *inode)
1165     {
1166     	mark_buffer_dirty(bh);
1167     	buffer_insert_inode_queue(bh, inode);
1168     }
1169     
1170     extern void balance_dirty(void);
1171     extern int check_disk_change(kdev_t);
1172     extern int invalidate_inodes(struct super_block *);
1173     extern int invalidate_device(kdev_t, int);
1174     extern void invalidate_inode_pages(struct inode *);
1175     extern void invalidate_inode_pages2(struct address_space *);
1176     extern void invalidate_inode_buffers(struct inode *);
1177     #define invalidate_buffers(dev)	__invalidate_buffers((dev), 0, 0)
1178     #define destroy_buffers(dev)	__invalidate_buffers((dev), 1, 0)
1179     #define update_buffers(dev)			\
1180     do {						\
1181     	__invalidate_buffers((dev), 0, 1);	\
1182     	__invalidate_buffers((dev), 0, 2);	\
1183     } while (0)
1184     extern void __invalidate_buffers(kdev_t dev, int, int);
1185     extern void sync_inodes(kdev_t);
1186     extern void sync_unlocked_inodes(void);
1187     extern void write_inode_now(struct inode *, int);
1188     extern int sync_buffers(kdev_t, int);
1189     extern void sync_dev(kdev_t);
1190     extern int fsync_dev(kdev_t);
1191     extern int fsync_super(struct super_block *);
1192     extern int fsync_no_super(kdev_t);
1193     extern void sync_inodes_sb(struct super_block *);
1194     extern int osync_inode_buffers(struct inode *);
1195     extern int osync_inode_data_buffers(struct inode *);
1196     extern int fsync_inode_buffers(struct inode *);
1197     extern int fsync_inode_data_buffers(struct inode *);
1198     extern int inode_has_buffers(struct inode *);
1199     extern void filemap_fdatasync(struct address_space *);
1200     extern void filemap_fdatawait(struct address_space *);
1201     extern void sync_supers(kdev_t);
1202     extern int bmap(struct inode *, int);
1203     extern int notify_change(struct dentry *, struct iattr *);
1204     extern int permission(struct inode *, int);
1205     extern int vfs_permission(struct inode *, int);
1206     extern int get_write_access(struct inode *);
1207     extern int deny_write_access(struct file *);
1208     static inline void put_write_access(struct inode * inode)
1209     {
1210     	atomic_dec(&inode->i_writecount);
1211     }
1212     static inline void allow_write_access(struct file *file)
1213     {
1214     	if (file)
1215     		atomic_inc(&file->f_dentry->d_inode->i_writecount);
1216     }
1217     extern int do_pipe(int *);
1218     
1219     extern int open_namei(const char *, int, int, struct nameidata *);
1220     
1221     extern int kernel_read(struct file *, unsigned long, char *, unsigned long);
1222     extern struct file * open_exec(const char *);
1223      
1224     /* fs/dcache.c -- generic fs support functions */
1225     extern int is_subdir(struct dentry *, struct dentry *);
1226     extern ino_t find_inode_number(struct dentry *, struct qstr *);
1227     
1228     /*
1229      * Kernel pointers have redundant information, so we can use a
1230      * scheme where we can return either an error code or a dentry
1231      * pointer with the same return value.
1232      *
1233      * This should be a per-architecture thing, to allow different
1234      * error and pointer decisions.
1235      */
1236     static inline void *ERR_PTR(long error)
1237     {
1238     	return (void *) error;
1239     }
1240     
1241     static inline long PTR_ERR(const void *ptr)
1242     {
1243     	return (long) ptr;
1244     }
1245     
1246     static inline long IS_ERR(const void *ptr)
1247     {
1248     	return (unsigned long)ptr > (unsigned long)-1000L;
1249     }
1250     
1251     /*
1252      * The bitmask for a lookup event:
1253      *  - follow links at the end
1254      *  - require a directory
1255      *  - ending slashes ok even for nonexistent files
1256      *  - internal "there are more path compnents" flag
1257      */
1258     #define LOOKUP_FOLLOW		(1)
1259     #define LOOKUP_DIRECTORY	(2)
1260     #define LOOKUP_CONTINUE		(4)
1261     #define LOOKUP_POSITIVE		(8)
1262     #define LOOKUP_PARENT		(16)
1263     #define LOOKUP_NOALT		(32)
1264     /*
1265      * Type of the last component on LOOKUP_PARENT
1266      */
1267     enum {LAST_NORM, LAST_ROOT, LAST_DOT, LAST_DOTDOT, LAST_BIND};
1268     
1269     /*
1270      * "descriptor" for what we're up to with a read for sendfile().
1271      * This allows us to use the same read code yet
1272      * have multiple different users of the data that
1273      * we read from a file.
1274      *
1275      * The simplest case just copies the data to user
1276      * mode.
1277      */
1278     typedef struct {
1279     	size_t written;
1280     	size_t count;
1281     	char * buf;
1282     	int error;
1283     } read_descriptor_t;
1284     
1285     typedef int (*read_actor_t)(read_descriptor_t *, struct page *, unsigned long, unsigned long);
1286     
1287     /* needed for stackable file system support */
1288     extern loff_t default_llseek(struct file *file, loff_t offset, int origin);
1289     
1290     extern int __user_walk(const char *, unsigned, struct nameidata *);
1291     extern int path_init(const char *, unsigned, struct nameidata *);
1292     extern int path_walk(const char *, struct nameidata *);
1293     extern void path_release(struct nameidata *);
1294     extern int follow_down(struct vfsmount **, struct dentry **);
1295     extern int follow_up(struct vfsmount **, struct dentry **);
1296     extern struct dentry * lookup_one_len(const char *, struct dentry *, int);
1297     extern struct dentry * lookup_hash(struct qstr *, struct dentry *);
1298     #define user_path_walk(name,nd)	 __user_walk(name, LOOKUP_FOLLOW|LOOKUP_POSITIVE, nd)
1299     #define user_path_walk_link(name,nd) __user_walk(name, LOOKUP_POSITIVE, nd)
1300     
1301     extern void iput(struct inode *);
1302     extern void force_delete(struct inode *);
1303     extern struct inode * igrab(struct inode *);
1304     extern ino_t iunique(struct super_block *, ino_t);
1305     
1306     typedef int (*find_inode_t)(struct inode *, unsigned long, void *);
1307     extern struct inode * iget4(struct super_block *, unsigned long, find_inode_t, void *);
1308     static inline struct inode *iget(struct super_block *sb, unsigned long ino)
1309     {
1310     	return iget4(sb, ino, NULL, NULL);
1311     }
1312     
1313     extern void clear_inode(struct inode *);
1314     extern struct inode * get_empty_inode(void);
1315     static inline struct inode * new_inode(struct super_block *sb)
1316     {
1317     	struct inode *inode = get_empty_inode();
1318     	if (inode) {
1319     		inode->i_sb = sb;
1320     		inode->i_dev = sb->s_dev;
1321     	}
1322     	return inode;
1323     }
1324     extern void remove_suid(struct inode *inode);
1325     
1326     extern void insert_inode_hash(struct inode *);
1327     extern void remove_inode_hash(struct inode *);
1328     extern struct file * get_empty_filp(void);
1329     extern void file_move(struct file *f, struct list_head *list);
1330     extern struct buffer_head * get_hash_table(kdev_t, int, int);
1331     extern struct buffer_head * getblk(kdev_t, int, int);
1332     extern void ll_rw_block(int, int, struct buffer_head * bh[]);
1333     extern void submit_bh(int, struct buffer_head *);
1334     extern int is_read_only(kdev_t);
1335     extern void __brelse(struct buffer_head *);
1336     static inline void brelse(struct buffer_head *buf)
1337     {
1338     	if (buf)
1339     		__brelse(buf);
1340     }
1341     extern void __bforget(struct buffer_head *);
1342     static inline void bforget(struct buffer_head *buf)
1343     {
1344     	if (buf)
1345     		__bforget(buf);
1346     }
1347     extern void set_blocksize(kdev_t, int);
1348     extern struct buffer_head * bread(kdev_t, int, int);
1349     extern void wakeup_bdflush(void);
1350     
1351     extern int brw_page(int, struct page *, kdev_t, int [], int);
1352     
1353     typedef int (get_block_t)(struct inode*,long,struct buffer_head*,int);
1354     
1355     /* Generic buffer handling for block filesystems.. */
1356     extern int discard_bh_page(struct page *, unsigned long, int);
1357     #define block_flushpage(page, offset) discard_bh_page(page, offset, 1)
1358     #define block_invalidate_page(page) discard_bh_page(page, 0, 0)
1359     extern int block_symlink(struct inode *, const char *, int);
1360     extern int block_write_full_page(struct page*, get_block_t*);
1361     extern int block_read_full_page(struct page*, get_block_t*);
1362     extern int block_prepare_write(struct page*, unsigned, unsigned, get_block_t*);
1363     extern int cont_prepare_write(struct page*, unsigned, unsigned, get_block_t*,
1364     				unsigned long *);
1365     extern int block_sync_page(struct page *);
1366     
1367     int generic_block_bmap(struct address_space *, long, get_block_t *);
1368     int generic_commit_write(struct file *, struct page *, unsigned, unsigned);
1369     int block_truncate_page(struct address_space *, loff_t, get_block_t *);
1370     extern int generic_direct_IO(int, struct inode *, struct kiobuf *, unsigned long, int, get_block_t *);
1371     extern void create_empty_buffers(struct page *, kdev_t, unsigned long);
1372     
1373     extern int waitfor_one_page(struct page*);
1374     extern int generic_file_mmap(struct file *, struct vm_area_struct *);
1375     extern int file_read_actor(read_descriptor_t * desc, struct page *page, unsigned long offset, unsigned long size);
1376     extern ssize_t generic_file_read(struct file *, char *, size_t, loff_t *);
1377     extern ssize_t generic_file_write(struct file *, const char *, size_t, loff_t *);
1378     extern void do_generic_file_read(struct file *, loff_t *, read_descriptor_t *, read_actor_t);
1379     extern loff_t no_llseek(struct file *file, loff_t offset, int origin);
1380     extern loff_t generic_file_llseek(struct file *file, loff_t offset, int origin);
1381     extern ssize_t generic_read_dir(struct file *, char *, size_t, loff_t *);
1382     extern int generic_file_open(struct inode * inode, struct file * filp);
1383     
1384     extern struct file_operations generic_ro_fops;
1385     
1386     extern int vfs_readlink(struct dentry *, char *, int, const char *);
1387     extern int vfs_follow_link(struct nameidata *, const char *);
1388     extern int page_readlink(struct dentry *, char *, int);
1389     extern int page_follow_link(struct dentry *, struct nameidata *);
1390     extern struct inode_operations page_symlink_inode_operations;
1391     
1392     extern int vfs_readdir(struct file *, filldir_t, void *);
1393     extern int dcache_readdir(struct file *, void *, filldir_t);
1394     
1395     extern struct file_system_type *get_fs_type(const char *name);
1396     extern struct super_block *get_super(kdev_t);
1397     extern void drop_super(struct super_block *sb);
1398     static inline int is_mounted(kdev_t dev)
1399     {
1400     	struct super_block *sb = get_super(dev);
1401     	if (sb) {
1402     		drop_super(sb);
1403     		return 1;
1404     	}
1405     	return 0;
1406     }
1407     unsigned long generate_cluster(kdev_t, int b[], int);
1408     unsigned long generate_cluster_swab32(kdev_t, int b[], int);
1409     extern kdev_t ROOT_DEV;
1410     extern char root_device_name[];
1411     
1412     
1413     extern void show_buffers(void);
1414     extern void mount_root(void);
1415     
1416     #ifdef CONFIG_BLK_DEV_INITRD
1417     extern kdev_t real_root_dev;
1418     extern int change_root(kdev_t, const char *);
1419     #endif
1420     
1421     extern ssize_t char_read(struct file *, char *, size_t, loff_t *);
1422     extern ssize_t block_read(struct file *, char *, size_t, loff_t *);
1423     extern int read_ahead[];
1424     
1425     extern ssize_t char_write(struct file *, const char *, size_t, loff_t *);
1426     extern ssize_t block_write(struct file *, const char *, size_t, loff_t *);
1427     
1428     extern int file_fsync(struct file *, struct dentry *, int);
1429     extern int generic_buffer_fdatasync(struct inode *inode, unsigned long start_idx, unsigned long end_idx);
1430     extern int generic_osync_inode(struct inode *, int);
1431     #define OSYNC_METADATA (1<<0)
1432     #define OSYNC_DATA (1<<1)
1433     #define OSYNC_INODE (1<<2)
1434     
1435     extern int inode_change_ok(struct inode *, struct iattr *);
1436     extern int inode_setattr(struct inode *, struct iattr *);
1437     
1438     /*
1439      * Common dentry functions for inclusion in the VFS
1440      * or in other stackable file systems.  Some of these
1441      * functions were in linux/fs/ C (VFS) files.
1442      *
1443      */
1444     
1445     /*
1446      * Locking the parent is needed to:
1447      *  - serialize directory operations
1448      *  - make sure the parent doesn't change from
1449      *    under us in the middle of an operation.
1450      *
1451      * NOTE! Right now we'd rather use a "struct inode"
1452      * for this, but as I expect things to move toward
1453      * using dentries instead for most things it is
1454      * probably better to start with the conceptually
1455      * better interface of relying on a path of dentries.
1456      */
1457     static inline struct dentry *lock_parent(struct dentry *dentry)
1458     {
1459     	struct dentry *dir = dget(dentry->d_parent);
1460     
1461     	down(&dir->d_inode->i_sem);
1462     	return dir;
1463     }
1464     
1465     static inline struct dentry *get_parent(struct dentry *dentry)
1466     {
1467     	return dget(dentry->d_parent);
1468     }
1469     
1470     static inline void unlock_dir(struct dentry *dir)
1471     {
1472     	up(&dir->d_inode->i_sem);
1473     	dput(dir);
1474     }
1475     
1476     /*
1477      * Whee.. Deadlock country. Happily there are only two VFS
1478      * operations that does this..
1479      */
1480     static inline void double_down(struct semaphore *s1, struct semaphore *s2)
1481     {
1482     	if (s1 != s2) {
1483     		if ((unsigned long) s1 < (unsigned long) s2) {
1484     			struct semaphore *tmp = s2;
1485     			s2 = s1; s1 = tmp;
1486     		}
1487     		down(s1);
1488     	}
1489     	down(s2);
1490     }
1491     
1492     /*
1493      * Ewwwwwwww... _triple_ lock. We are guaranteed that the 3rd argument is
1494      * not equal to 1st and not equal to 2nd - the first case (target is parent of
1495      * source) would be already caught, the second is plain impossible (target is
1496      * its own parent and that case would be caught even earlier). Very messy.
1497      * I _think_ that it works, but no warranties - please, look it through.
1498      * Pox on bloody lusers who mandated overwriting rename() for directories...
1499      */
1500     
1501     static inline void triple_down(struct semaphore *s1,
1502     			       struct semaphore *s2,
1503     			       struct semaphore *s3)
1504     {
1505     	if (s1 != s2) {
1506     		if ((unsigned long) s1 < (unsigned long) s2) {
1507     			if ((unsigned long) s1 < (unsigned long) s3) {
1508     				struct semaphore *tmp = s3;
1509     				s3 = s1; s1 = tmp;
1510     			}
1511     			if ((unsigned long) s1 < (unsigned long) s2) {
1512     				struct semaphore *tmp = s2;
1513     				s2 = s1; s1 = tmp;
1514     			}
1515     		} else {
1516     			if ((unsigned long) s1 < (unsigned long) s3) {
1517     				struct semaphore *tmp = s3;
1518     				s3 = s1; s1 = tmp;
1519     			}
1520     			if ((unsigned long) s2 < (unsigned long) s3) {
1521     				struct semaphore *tmp = s3;
1522     				s3 = s2; s2 = tmp;
1523     			}
1524     		}
1525     		down(s1);
1526     	} else if ((unsigned long) s2 < (unsigned long) s3) {
1527     		struct semaphore *tmp = s3;
1528     		s3 = s2; s2 = tmp;
1529     	}
1530     	down(s2);
1531     	down(s3);
1532     }
1533     
1534     static inline void double_up(struct semaphore *s1, struct semaphore *s2)
1535     {
1536     	up(s1);
1537     	if (s1 != s2)
1538     		up(s2);
1539     }
1540     
1541     static inline void triple_up(struct semaphore *s1,
1542     			     struct semaphore *s2,
1543     			     struct semaphore *s3)
1544     {
1545     	up(s1);
1546     	if (s1 != s2)
1547     		up(s2);
1548     	up(s3);
1549     }
1550     
1551     static inline void double_lock(struct dentry *d1, struct dentry *d2)
1552     {
1553     	double_down(&d1->d_inode->i_sem, &d2->d_inode->i_sem);
1554     }
1555     
1556     static inline void double_unlock(struct dentry *d1, struct dentry *d2)
1557     {
1558     	double_up(&d1->d_inode->i_sem,&d2->d_inode->i_sem);
1559     	dput(d1);
1560     	dput(d2);
1561     }
1562     
1563     #endif /* __KERNEL__ */
1564     
1565     #endif /* _LINUX_FS_H */
1566