• Home
  • Line#
  • Scopes#
  • Navigate#
  • Raw
  • Download
1 /*
2  * linux/include/linux/jbd.h
3  *
4  * Written by Stephen C. Tweedie <sct@redhat.com>
5  *
6  * Copyright 1998-2000 Red Hat, Inc --- All Rights Reserved
7  *
8  * This file is part of the Linux kernel and is made available under
9  * the terms of the GNU General Public License, version 2, or at your
10  * option, any later version, incorporated herein by reference.
11  *
12  * Definitions for transaction data structures for the buffer cache
13  * filesystem journaling support.
14  */
15 
16 #ifndef _LINUX_JBD_H
17 #define _LINUX_JBD_H
18 
19 /* Allow this file to be included directly into e2fsprogs */
20 #ifndef __KERNEL__
21 #include "jfs_compat.h"
22 #define JFS_DEBUG
23 #define jfs_debug jbd_debug
24 #else
25 
26 #include <linux/types.h>
27 #include <linux/buffer_head.h>
28 #include <linux/journal-head.h>
29 #include <linux/stddef.h>
30 #include <linux/bit_spinlock.h>
31 #include <linux/mutex.h>
32 #include <linux/timer.h>
33 #include <linux/lockdep.h>
34 
35 #define journal_oom_retry 1
36 
37 /*
38  * Define JBD_PARANIOD_IOFAIL to cause a kernel BUG() if ext3 finds
39  * certain classes of error which can occur due to failed IOs.  Under
40  * normal use we want ext3 to continue after such errors, because
41  * hardware _can_ fail, but for debugging purposes when running tests on
42  * known-good hardware we may want to trap these errors.
43  */
44 #undef JBD_PARANOID_IOFAIL
45 
46 /*
47  * The default maximum commit age, in seconds.
48  */
49 #define JBD_DEFAULT_MAX_COMMIT_AGE 5
50 
51 #ifdef CONFIG_JBD_DEBUG
52 /*
53  * Define JBD_EXPENSIVE_CHECKING to enable more expensive internal
54  * consistency checks.  By default we don't do this unless
55  * CONFIG_JBD_DEBUG is on.
56  */
57 #define JBD_EXPENSIVE_CHECKING
58 extern u8 journal_enable_debug;
59 
60 #define jbd_debug(n, f, a...)						\
61 	do {								\
62 		if ((n) <= journal_enable_debug) {			\
63 			printk (KERN_DEBUG "(%s, %d): %s: ",		\
64 				__FILE__, __LINE__, __func__);	\
65 			printk (f, ## a);				\
66 		}							\
67 	} while (0)
68 #else
69 #define jbd_debug(f, a...)	/**/
70 #endif
71 
jbd_alloc(size_t size,gfp_t flags)72 static inline void *jbd_alloc(size_t size, gfp_t flags)
73 {
74 	return (void *)__get_free_pages(flags, get_order(size));
75 }
76 
jbd_free(void * ptr,size_t size)77 static inline void jbd_free(void *ptr, size_t size)
78 {
79 	free_pages((unsigned long)ptr, get_order(size));
80 };
81 
82 #define JFS_MIN_JOURNAL_BLOCKS 1024
83 
84 
85 /**
86  * typedef handle_t - The handle_t type represents a single atomic update being performed by some process.
87  *
88  * All filesystem modifications made by the process go
89  * through this handle.  Recursive operations (such as quota operations)
90  * are gathered into a single update.
91  *
92  * The buffer credits field is used to account for journaled buffers
93  * being modified by the running process.  To ensure that there is
94  * enough log space for all outstanding operations, we need to limit the
95  * number of outstanding buffers possible at any time.  When the
96  * operation completes, any buffer credits not used are credited back to
97  * the transaction, so that at all times we know how many buffers the
98  * outstanding updates on a transaction might possibly touch.
99  *
100  * This is an opaque datatype.
101  **/
102 typedef struct handle_s		handle_t;	/* Atomic operation type */
103 
104 
105 /**
106  * typedef journal_t - The journal_t maintains all of the journaling state information for a single filesystem.
107  *
108  * journal_t is linked to from the fs superblock structure.
109  *
110  * We use the journal_t to keep track of all outstanding transaction
111  * activity on the filesystem, and to manage the state of the log
112  * writing process.
113  *
114  * This is an opaque datatype.
115  **/
116 typedef struct journal_s	journal_t;	/* Journal control structure */
117 #endif
118 
119 /*
120  * Internal structures used by the logging mechanism:
121  */
122 
123 #define JFS_MAGIC_NUMBER 0xc03b3998U /* The first 4 bytes of /dev/random! */
124 
125 /*
126  * On-disk structures
127  */
128 
129 /*
130  * Descriptor block types:
131  */
132 
133 #define JFS_DESCRIPTOR_BLOCK	1
134 #define JFS_COMMIT_BLOCK	2
135 #define JFS_SUPERBLOCK_V1	3
136 #define JFS_SUPERBLOCK_V2	4
137 #define JFS_REVOKE_BLOCK	5
138 
139 /*
140  * Standard header for all descriptor blocks:
141  */
142 typedef struct journal_header_s
143 {
144 	__be32		h_magic;
145 	__be32		h_blocktype;
146 	__be32		h_sequence;
147 } journal_header_t;
148 
149 
150 /*
151  * The block tag: used to describe a single buffer in the journal
152  */
153 typedef struct journal_block_tag_s
154 {
155 	__be32		t_blocknr;	/* The on-disk block number */
156 	__be32		t_flags;	/* See below */
157 } journal_block_tag_t;
158 
159 /*
160  * The revoke descriptor: used on disk to describe a series of blocks to
161  * be revoked from the log
162  */
163 typedef struct journal_revoke_header_s
164 {
165 	journal_header_t r_header;
166 	__be32		 r_count;	/* Count of bytes used in the block */
167 } journal_revoke_header_t;
168 
169 
170 /* Definitions for the journal tag flags word: */
171 #define JFS_FLAG_ESCAPE		1	/* on-disk block is escaped */
172 #define JFS_FLAG_SAME_UUID	2	/* block has same uuid as previous */
173 #define JFS_FLAG_DELETED	4	/* block deleted by this transaction */
174 #define JFS_FLAG_LAST_TAG	8	/* last tag in this descriptor block */
175 
176 
177 /*
178  * The journal superblock.  All fields are in big-endian byte order.
179  */
180 typedef struct journal_superblock_s
181 {
182 /* 0x0000 */
183 	journal_header_t s_header;
184 
185 /* 0x000C */
186 	/* Static information describing the journal */
187 	__be32	s_blocksize;		/* journal device blocksize */
188 	__be32	s_maxlen;		/* total blocks in journal file */
189 	__be32	s_first;		/* first block of log information */
190 
191 /* 0x0018 */
192 	/* Dynamic information describing the current state of the log */
193 	__be32	s_sequence;		/* first commit ID expected in log */
194 	__be32	s_start;		/* blocknr of start of log */
195 
196 /* 0x0020 */
197 	/* Error value, as set by journal_abort(). */
198 	__be32	s_errno;
199 
200 /* 0x0024 */
201 	/* Remaining fields are only valid in a version-2 superblock */
202 	__be32	s_feature_compat;	/* compatible feature set */
203 	__be32	s_feature_incompat;	/* incompatible feature set */
204 	__be32	s_feature_ro_compat;	/* readonly-compatible feature set */
205 /* 0x0030 */
206 	__u8	s_uuid[16];		/* 128-bit uuid for journal */
207 
208 /* 0x0040 */
209 	__be32	s_nr_users;		/* Nr of filesystems sharing log */
210 
211 	__be32	s_dynsuper;		/* Blocknr of dynamic superblock copy*/
212 
213 /* 0x0048 */
214 	__be32	s_max_transaction;	/* Limit of journal blocks per trans.*/
215 	__be32	s_max_trans_data;	/* Limit of data blocks per trans. */
216 
217 /* 0x0050 */
218 	__u32	s_padding[44];
219 
220 /* 0x0100 */
221 	__u8	s_users[16*48];		/* ids of all fs'es sharing the log */
222 /* 0x0400 */
223 } journal_superblock_t;
224 
225 #define JFS_HAS_COMPAT_FEATURE(j,mask)					\
226 	((j)->j_format_version >= 2 &&					\
227 	 ((j)->j_superblock->s_feature_compat & cpu_to_be32((mask))))
228 #define JFS_HAS_RO_COMPAT_FEATURE(j,mask)				\
229 	((j)->j_format_version >= 2 &&					\
230 	 ((j)->j_superblock->s_feature_ro_compat & cpu_to_be32((mask))))
231 #define JFS_HAS_INCOMPAT_FEATURE(j,mask)				\
232 	((j)->j_format_version >= 2 &&					\
233 	 ((j)->j_superblock->s_feature_incompat & cpu_to_be32((mask))))
234 
235 #define JFS_FEATURE_INCOMPAT_REVOKE	0x00000001
236 
237 /* Features known to this kernel version: */
238 #define JFS_KNOWN_COMPAT_FEATURES	0
239 #define JFS_KNOWN_ROCOMPAT_FEATURES	0
240 #define JFS_KNOWN_INCOMPAT_FEATURES	JFS_FEATURE_INCOMPAT_REVOKE
241 
242 #ifdef __KERNEL__
243 
244 #include <linux/fs.h>
245 #include <linux/sched.h>
246 
247 #define J_ASSERT(assert)	BUG_ON(!(assert))
248 
249 #if defined(CONFIG_BUFFER_DEBUG)
250 void buffer_assertion_failure(struct buffer_head *bh);
251 #define J_ASSERT_BH(bh, expr)						\
252 	do {								\
253 		if (!(expr))						\
254 			buffer_assertion_failure(bh);			\
255 		J_ASSERT(expr);						\
256 	} while (0)
257 #define J_ASSERT_JH(jh, expr)	J_ASSERT_BH(jh2bh(jh), expr)
258 #else
259 #define J_ASSERT_BH(bh, expr)	J_ASSERT(expr)
260 #define J_ASSERT_JH(jh, expr)	J_ASSERT(expr)
261 #endif
262 
263 #if defined(JBD_PARANOID_IOFAIL)
264 #define J_EXPECT(expr, why...)		J_ASSERT(expr)
265 #define J_EXPECT_BH(bh, expr, why...)	J_ASSERT_BH(bh, expr)
266 #define J_EXPECT_JH(jh, expr, why...)	J_ASSERT_JH(jh, expr)
267 #else
268 #define __journal_expect(expr, why...)					     \
269 	({								     \
270 		int val = (expr);					     \
271 		if (!val) {						     \
272 			printk(KERN_ERR					     \
273 				"EXT3-fs unexpected failure: %s;\n",# expr); \
274 			printk(KERN_ERR why "\n");			     \
275 		}							     \
276 		val;							     \
277 	})
278 #define J_EXPECT(expr, why...)		__journal_expect(expr, ## why)
279 #define J_EXPECT_BH(bh, expr, why...)	__journal_expect(expr, ## why)
280 #define J_EXPECT_JH(jh, expr, why...)	__journal_expect(expr, ## why)
281 #endif
282 
283 enum jbd_state_bits {
284 	BH_JBD			/* Has an attached ext3 journal_head */
285 	  = BH_PrivateStart,
286 	BH_JWrite,		/* Being written to log (@@@ DEBUGGING) */
287 	BH_Freed,		/* Has been freed (truncated) */
288 	BH_Revoked,		/* Has been revoked from the log */
289 	BH_RevokeValid,		/* Revoked flag is valid */
290 	BH_JBDDirty,		/* Is dirty but journaled */
291 	BH_State,		/* Pins most journal_head state */
292 	BH_JournalHead,		/* Pins bh->b_private and jh->b_bh */
293 	BH_Unshadow,		/* Dummy bit, for BJ_Shadow wakeup filtering */
294 };
295 
BUFFER_FNS(JBD,jbd)296 BUFFER_FNS(JBD, jbd)
297 BUFFER_FNS(JWrite, jwrite)
298 BUFFER_FNS(JBDDirty, jbddirty)
299 TAS_BUFFER_FNS(JBDDirty, jbddirty)
300 BUFFER_FNS(Revoked, revoked)
301 TAS_BUFFER_FNS(Revoked, revoked)
302 BUFFER_FNS(RevokeValid, revokevalid)
303 TAS_BUFFER_FNS(RevokeValid, revokevalid)
304 BUFFER_FNS(Freed, freed)
305 
306 static inline struct buffer_head *jh2bh(struct journal_head *jh)
307 {
308 	return jh->b_bh;
309 }
310 
bh2jh(struct buffer_head * bh)311 static inline struct journal_head *bh2jh(struct buffer_head *bh)
312 {
313 	return bh->b_private;
314 }
315 
jbd_lock_bh_state(struct buffer_head * bh)316 static inline void jbd_lock_bh_state(struct buffer_head *bh)
317 {
318 	bit_spin_lock(BH_State, &bh->b_state);
319 }
320 
jbd_trylock_bh_state(struct buffer_head * bh)321 static inline int jbd_trylock_bh_state(struct buffer_head *bh)
322 {
323 	return bit_spin_trylock(BH_State, &bh->b_state);
324 }
325 
jbd_is_locked_bh_state(struct buffer_head * bh)326 static inline int jbd_is_locked_bh_state(struct buffer_head *bh)
327 {
328 	return bit_spin_is_locked(BH_State, &bh->b_state);
329 }
330 
jbd_unlock_bh_state(struct buffer_head * bh)331 static inline void jbd_unlock_bh_state(struct buffer_head *bh)
332 {
333 	bit_spin_unlock(BH_State, &bh->b_state);
334 }
335 
jbd_lock_bh_journal_head(struct buffer_head * bh)336 static inline void jbd_lock_bh_journal_head(struct buffer_head *bh)
337 {
338 	bit_spin_lock(BH_JournalHead, &bh->b_state);
339 }
340 
jbd_unlock_bh_journal_head(struct buffer_head * bh)341 static inline void jbd_unlock_bh_journal_head(struct buffer_head *bh)
342 {
343 	bit_spin_unlock(BH_JournalHead, &bh->b_state);
344 }
345 
346 struct jbd_revoke_table_s;
347 
348 /**
349  * struct handle_s - this is the concrete type associated with handle_t.
350  * @h_transaction: Which compound transaction is this update a part of?
351  * @h_buffer_credits: Number of remaining buffers we are allowed to dirty.
352  * @h_ref: Reference count on this handle
353  * @h_err: Field for caller's use to track errors through large fs operations
354  * @h_sync: flag for sync-on-close
355  * @h_jdata: flag to force data journaling
356  * @h_aborted: flag indicating fatal error on handle
357  * @h_lockdep_map: lockdep info for debugging lock problems
358  */
359 struct handle_s
360 {
361 	/* Which compound transaction is this update a part of? */
362 	transaction_t		*h_transaction;
363 
364 	/* Number of remaining buffers we are allowed to dirty: */
365 	int			h_buffer_credits;
366 
367 	/* Reference count on this handle */
368 	int			h_ref;
369 
370 	/* Field for caller's use to track errors through large fs */
371 	/* operations */
372 	int			h_err;
373 
374 	/* Flags [no locking] */
375 	unsigned int	h_sync:		1;	/* sync-on-close */
376 	unsigned int	h_jdata:	1;	/* force data journaling */
377 	unsigned int	h_aborted:	1;	/* fatal error on handle */
378 
379 #ifdef CONFIG_DEBUG_LOCK_ALLOC
380 	struct lockdep_map	h_lockdep_map;
381 #endif
382 };
383 
384 
385 /* The transaction_t type is the guts of the journaling mechanism.  It
386  * tracks a compound transaction through its various states:
387  *
388  * RUNNING:	accepting new updates
389  * LOCKED:	Updates still running but we don't accept new ones
390  * RUNDOWN:	Updates are tidying up but have finished requesting
391  *		new buffers to modify (state not used for now)
392  * FLUSH:       All updates complete, but we are still writing to disk
393  * COMMIT:      All data on disk, writing commit record
394  * FINISHED:	We still have to keep the transaction for checkpointing.
395  *
396  * The transaction keeps track of all of the buffers modified by a
397  * running transaction, and all of the buffers committed but not yet
398  * flushed to home for finished transactions.
399  */
400 
401 /*
402  * Lock ranking:
403  *
404  *    j_list_lock
405  *      ->jbd_lock_bh_journal_head()	(This is "innermost")
406  *
407  *    j_state_lock
408  *    ->jbd_lock_bh_state()
409  *
410  *    jbd_lock_bh_state()
411  *    ->j_list_lock
412  *
413  *    j_state_lock
414  *    ->t_handle_lock
415  *
416  *    j_state_lock
417  *    ->j_list_lock			(journal_unmap_buffer)
418  *
419  */
420 
421 struct transaction_s
422 {
423 	/* Pointer to the journal for this transaction. [no locking] */
424 	journal_t		*t_journal;
425 
426 	/* Sequence number for this transaction [no locking] */
427 	tid_t			t_tid;
428 
429 	/*
430 	 * Transaction's current state
431 	 * [no locking - only kjournald alters this]
432 	 * [j_list_lock] guards transition of a transaction into T_FINISHED
433 	 * state and subsequent call of __journal_drop_transaction()
434 	 * FIXME: needs barriers
435 	 * KLUDGE: [use j_state_lock]
436 	 */
437 	enum {
438 		T_RUNNING,
439 		T_LOCKED,
440 		T_RUNDOWN,
441 		T_FLUSH,
442 		T_COMMIT,
443 		T_FINISHED
444 	}			t_state;
445 
446 	/*
447 	 * Where in the log does this transaction's commit start? [no locking]
448 	 */
449 	unsigned long		t_log_start;
450 
451 	/* Number of buffers on the t_buffers list [j_list_lock] */
452 	int			t_nr_buffers;
453 
454 	/*
455 	 * Doubly-linked circular list of all buffers reserved but not yet
456 	 * modified by this transaction [j_list_lock]
457 	 */
458 	struct journal_head	*t_reserved_list;
459 
460 	/*
461 	 * Doubly-linked circular list of all buffers under writeout during
462 	 * commit [j_list_lock]
463 	 */
464 	struct journal_head	*t_locked_list;
465 
466 	/*
467 	 * Doubly-linked circular list of all metadata buffers owned by this
468 	 * transaction [j_list_lock]
469 	 */
470 	struct journal_head	*t_buffers;
471 
472 	/*
473 	 * Doubly-linked circular list of all data buffers still to be
474 	 * flushed before this transaction can be committed [j_list_lock]
475 	 */
476 	struct journal_head	*t_sync_datalist;
477 
478 	/*
479 	 * Doubly-linked circular list of all forget buffers (superseded
480 	 * buffers which we can un-checkpoint once this transaction commits)
481 	 * [j_list_lock]
482 	 */
483 	struct journal_head	*t_forget;
484 
485 	/*
486 	 * Doubly-linked circular list of all buffers still to be flushed before
487 	 * this transaction can be checkpointed. [j_list_lock]
488 	 */
489 	struct journal_head	*t_checkpoint_list;
490 
491 	/*
492 	 * Doubly-linked circular list of all buffers submitted for IO while
493 	 * checkpointing. [j_list_lock]
494 	 */
495 	struct journal_head	*t_checkpoint_io_list;
496 
497 	/*
498 	 * Doubly-linked circular list of temporary buffers currently undergoing
499 	 * IO in the log [j_list_lock]
500 	 */
501 	struct journal_head	*t_iobuf_list;
502 
503 	/*
504 	 * Doubly-linked circular list of metadata buffers being shadowed by log
505 	 * IO.  The IO buffers on the iobuf list and the shadow buffers on this
506 	 * list match each other one for one at all times. [j_list_lock]
507 	 */
508 	struct journal_head	*t_shadow_list;
509 
510 	/*
511 	 * Doubly-linked circular list of control buffers being written to the
512 	 * log. [j_list_lock]
513 	 */
514 	struct journal_head	*t_log_list;
515 
516 	/*
517 	 * Protects info related to handles
518 	 */
519 	spinlock_t		t_handle_lock;
520 
521 	/*
522 	 * Number of outstanding updates running on this transaction
523 	 * [t_handle_lock]
524 	 */
525 	int			t_updates;
526 
527 	/*
528 	 * Number of buffers reserved for use by all handles in this transaction
529 	 * handle but not yet modified. [t_handle_lock]
530 	 */
531 	int			t_outstanding_credits;
532 
533 	/*
534 	 * Forward and backward links for the circular list of all transactions
535 	 * awaiting checkpoint. [j_list_lock]
536 	 */
537 	transaction_t		*t_cpnext, *t_cpprev;
538 
539 	/*
540 	 * When will the transaction expire (become due for commit), in jiffies?
541 	 * [no locking]
542 	 */
543 	unsigned long		t_expires;
544 
545 	/*
546 	 * When this transaction started, in nanoseconds [no locking]
547 	 */
548 	ktime_t			t_start_time;
549 
550 	/*
551 	 * How many handles used this transaction? [t_handle_lock]
552 	 */
553 	int t_handle_count;
554 
555 };
556 
557 /**
558  * struct journal_s - this is the concrete type associated with journal_t.
559  * @j_flags:  General journaling state flags
560  * @j_errno:  Is there an outstanding uncleared error on the journal (from a
561  *     prior abort)?
562  * @j_sb_buffer: First part of superblock buffer
563  * @j_superblock: Second part of superblock buffer
564  * @j_format_version: Version of the superblock format
565  * @j_state_lock: Protect the various scalars in the journal
566  * @j_barrier_count:  Number of processes waiting to create a barrier lock
567  * @j_barrier: The barrier lock itself
568  * @j_running_transaction: The current running transaction..
569  * @j_committing_transaction: the transaction we are pushing to disk
570  * @j_checkpoint_transactions: a linked circular list of all transactions
571  *  waiting for checkpointing
572  * @j_wait_transaction_locked: Wait queue for waiting for a locked transaction
573  *  to start committing, or for a barrier lock to be released
574  * @j_wait_logspace: Wait queue for waiting for checkpointing to complete
575  * @j_wait_done_commit: Wait queue for waiting for commit to complete
576  * @j_wait_checkpoint:  Wait queue to trigger checkpointing
577  * @j_wait_commit: Wait queue to trigger commit
578  * @j_wait_updates: Wait queue to wait for updates to complete
579  * @j_checkpoint_mutex: Mutex for locking against concurrent checkpoints
580  * @j_head: Journal head - identifies the first unused block in the journal
581  * @j_tail: Journal tail - identifies the oldest still-used block in the
582  *  journal.
583  * @j_free: Journal free - how many free blocks are there in the journal?
584  * @j_first: The block number of the first usable block
585  * @j_last: The block number one beyond the last usable block
586  * @j_dev: Device where we store the journal
587  * @j_blocksize: blocksize for the location where we store the journal.
588  * @j_blk_offset: starting block offset for into the device where we store the
589  *     journal
590  * @j_fs_dev: Device which holds the client fs.  For internal journal this will
591  *     be equal to j_dev
592  * @j_maxlen: Total maximum capacity of the journal region on disk.
593  * @j_list_lock: Protects the buffer lists and internal buffer state.
594  * @j_inode: Optional inode where we store the journal.  If present, all journal
595  *     block numbers are mapped into this inode via bmap().
596  * @j_tail_sequence:  Sequence number of the oldest transaction in the log
597  * @j_transaction_sequence: Sequence number of the next transaction to grant
598  * @j_commit_sequence: Sequence number of the most recently committed
599  *  transaction
600  * @j_commit_request: Sequence number of the most recent transaction wanting
601  *     commit
602  * @j_uuid: Uuid of client object.
603  * @j_task: Pointer to the current commit thread for this journal
604  * @j_max_transaction_buffers:  Maximum number of metadata buffers to allow in a
605  *     single compound commit transaction
606  * @j_commit_interval: What is the maximum transaction lifetime before we begin
607  *  a commit?
608  * @j_commit_timer:  The timer used to wakeup the commit thread
609  * @j_revoke_lock: Protect the revoke table
610  * @j_revoke: The revoke table - maintains the list of revoked blocks in the
611  *     current transaction.
612  * @j_revoke_table: alternate revoke tables for j_revoke
613  * @j_wbuf: array of buffer_heads for journal_commit_transaction
614  * @j_wbufsize: maximum number of buffer_heads allowed in j_wbuf, the
615  *	number that will fit in j_blocksize
616  * @j_last_sync_writer: most recent pid which did a synchronous write
617  * @j_average_commit_time: the average amount of time in nanoseconds it
618  *	takes to commit a transaction to the disk.
619  * @j_private: An opaque pointer to fs-private information.
620  */
621 
622 struct journal_s
623 {
624 	/* General journaling state flags [j_state_lock] */
625 	unsigned long		j_flags;
626 
627 	/*
628 	 * Is there an outstanding uncleared error on the journal (from a prior
629 	 * abort)? [j_state_lock]
630 	 */
631 	int			j_errno;
632 
633 	/* The superblock buffer */
634 	struct buffer_head	*j_sb_buffer;
635 	journal_superblock_t	*j_superblock;
636 
637 	/* Version of the superblock format */
638 	int			j_format_version;
639 
640 	/*
641 	 * Protect the various scalars in the journal
642 	 */
643 	spinlock_t		j_state_lock;
644 
645 	/*
646 	 * Number of processes waiting to create a barrier lock [j_state_lock]
647 	 */
648 	int			j_barrier_count;
649 
650 	/* The barrier lock itself */
651 	struct mutex		j_barrier;
652 
653 	/*
654 	 * Transactions: The current running transaction...
655 	 * [j_state_lock] [caller holding open handle]
656 	 */
657 	transaction_t		*j_running_transaction;
658 
659 	/*
660 	 * the transaction we are pushing to disk
661 	 * [j_state_lock] [caller holding open handle]
662 	 */
663 	transaction_t		*j_committing_transaction;
664 
665 	/*
666 	 * ... and a linked circular list of all transactions waiting for
667 	 * checkpointing. [j_list_lock]
668 	 */
669 	transaction_t		*j_checkpoint_transactions;
670 
671 	/*
672 	 * Wait queue for waiting for a locked transaction to start committing,
673 	 * or for a barrier lock to be released
674 	 */
675 	wait_queue_head_t	j_wait_transaction_locked;
676 
677 	/* Wait queue for waiting for checkpointing to complete */
678 	wait_queue_head_t	j_wait_logspace;
679 
680 	/* Wait queue for waiting for commit to complete */
681 	wait_queue_head_t	j_wait_done_commit;
682 
683 	/* Wait queue to trigger checkpointing */
684 	wait_queue_head_t	j_wait_checkpoint;
685 
686 	/* Wait queue to trigger commit */
687 	wait_queue_head_t	j_wait_commit;
688 
689 	/* Wait queue to wait for updates to complete */
690 	wait_queue_head_t	j_wait_updates;
691 
692 	/* Semaphore for locking against concurrent checkpoints */
693 	struct mutex		j_checkpoint_mutex;
694 
695 	/*
696 	 * Journal head: identifies the first unused block in the journal.
697 	 * [j_state_lock]
698 	 */
699 	unsigned long		j_head;
700 
701 	/*
702 	 * Journal tail: identifies the oldest still-used block in the journal.
703 	 * [j_state_lock]
704 	 */
705 	unsigned long		j_tail;
706 
707 	/*
708 	 * Journal free: how many free blocks are there in the journal?
709 	 * [j_state_lock]
710 	 */
711 	unsigned long		j_free;
712 
713 	/*
714 	 * Journal start and end: the block numbers of the first usable block
715 	 * and one beyond the last usable block in the journal. [j_state_lock]
716 	 */
717 	unsigned long		j_first;
718 	unsigned long		j_last;
719 
720 	/*
721 	 * Device, blocksize and starting block offset for the location where we
722 	 * store the journal.
723 	 */
724 	struct block_device	*j_dev;
725 	int			j_blocksize;
726 	unsigned long		j_blk_offset;
727 
728 	/*
729 	 * Device which holds the client fs.  For internal journal this will be
730 	 * equal to j_dev.
731 	 */
732 	struct block_device	*j_fs_dev;
733 
734 	/* Total maximum capacity of the journal region on disk. */
735 	unsigned int		j_maxlen;
736 
737 	/*
738 	 * Protects the buffer lists and internal buffer state.
739 	 */
740 	spinlock_t		j_list_lock;
741 
742 	/* Optional inode where we store the journal.  If present, all */
743 	/* journal block numbers are mapped into this inode via */
744 	/* bmap(). */
745 	struct inode		*j_inode;
746 
747 	/*
748 	 * Sequence number of the oldest transaction in the log [j_state_lock]
749 	 */
750 	tid_t			j_tail_sequence;
751 
752 	/*
753 	 * Sequence number of the next transaction to grant [j_state_lock]
754 	 */
755 	tid_t			j_transaction_sequence;
756 
757 	/*
758 	 * Sequence number of the most recently committed transaction
759 	 * [j_state_lock].
760 	 */
761 	tid_t			j_commit_sequence;
762 
763 	/*
764 	 * Sequence number of the most recent transaction wanting commit
765 	 * [j_state_lock]
766 	 */
767 	tid_t			j_commit_request;
768 
769 	/*
770 	 * Journal uuid: identifies the object (filesystem, LVM volume etc)
771 	 * backed by this journal.  This will eventually be replaced by an array
772 	 * of uuids, allowing us to index multiple devices within a single
773 	 * journal and to perform atomic updates across them.
774 	 */
775 	__u8			j_uuid[16];
776 
777 	/* Pointer to the current commit thread for this journal */
778 	struct task_struct	*j_task;
779 
780 	/*
781 	 * Maximum number of metadata buffers to allow in a single compound
782 	 * commit transaction
783 	 */
784 	int			j_max_transaction_buffers;
785 
786 	/*
787 	 * What is the maximum transaction lifetime before we begin a commit?
788 	 */
789 	unsigned long		j_commit_interval;
790 
791 	/* The timer used to wakeup the commit thread: */
792 	struct timer_list	j_commit_timer;
793 
794 	/*
795 	 * The revoke table: maintains the list of revoked blocks in the
796 	 * current transaction.  [j_revoke_lock]
797 	 */
798 	spinlock_t		j_revoke_lock;
799 	struct jbd_revoke_table_s *j_revoke;
800 	struct jbd_revoke_table_s *j_revoke_table[2];
801 
802 	/*
803 	 * array of bhs for journal_commit_transaction
804 	 */
805 	struct buffer_head	**j_wbuf;
806 	int			j_wbufsize;
807 
808 	/*
809 	 * this is the pid of the last person to run a synchronous operation
810 	 * through the journal.
811 	 */
812 	pid_t			j_last_sync_writer;
813 
814 	/*
815 	 * the average amount of time in nanoseconds it takes to commit a
816 	 * transaction to the disk.  [j_state_lock]
817 	 */
818 	u64			j_average_commit_time;
819 
820 	/*
821 	 * An opaque pointer to fs-private information.  ext3 puts its
822 	 * superblock pointer here
823 	 */
824 	void *j_private;
825 };
826 
827 /*
828  * Journal flag definitions
829  */
830 #define JFS_UNMOUNT	0x001	/* Journal thread is being destroyed */
831 #define JFS_ABORT	0x002	/* Journaling has been aborted for errors. */
832 #define JFS_ACK_ERR	0x004	/* The errno in the sb has been acked */
833 #define JFS_FLUSHED	0x008	/* The journal superblock has been flushed */
834 #define JFS_LOADED	0x010	/* The journal superblock has been loaded */
835 #define JFS_BARRIER	0x020	/* Use IDE barriers */
836 #define JFS_ABORT_ON_SYNCDATA_ERR	0x040  /* Abort the journal on file
837 						* data write error in ordered
838 						* mode */
839 
840 /*
841  * Function declarations for the journaling transaction and buffer
842  * management
843  */
844 
845 /* Filing buffers */
846 extern void journal_unfile_buffer(journal_t *, struct journal_head *);
847 extern void __journal_unfile_buffer(struct journal_head *);
848 extern void __journal_refile_buffer(struct journal_head *);
849 extern void journal_refile_buffer(journal_t *, struct journal_head *);
850 extern void __journal_file_buffer(struct journal_head *, transaction_t *, int);
851 extern void __journal_free_buffer(struct journal_head *bh);
852 extern void journal_file_buffer(struct journal_head *, transaction_t *, int);
853 extern void __journal_clean_data_list(transaction_t *transaction);
854 
855 /* Log buffer allocation */
856 extern struct journal_head * journal_get_descriptor_buffer(journal_t *);
857 int journal_next_log_block(journal_t *, unsigned long *);
858 
859 /* Commit management */
860 extern void journal_commit_transaction(journal_t *);
861 
862 /* Checkpoint list management */
863 int __journal_clean_checkpoint_list(journal_t *journal);
864 int __journal_remove_checkpoint(struct journal_head *);
865 void __journal_insert_checkpoint(struct journal_head *, transaction_t *);
866 
867 /* Buffer IO */
868 extern int
869 journal_write_metadata_buffer(transaction_t	  *transaction,
870 			      struct journal_head  *jh_in,
871 			      struct journal_head **jh_out,
872 			      unsigned long	   blocknr);
873 
874 /* Transaction locking */
875 extern void		__wait_on_journal (journal_t *);
876 
877 /*
878  * Journal locking.
879  *
880  * We need to lock the journal during transaction state changes so that nobody
881  * ever tries to take a handle on the running transaction while we are in the
882  * middle of moving it to the commit phase.  j_state_lock does this.
883  *
884  * Note that the locking is completely interrupt unsafe.  We never touch
885  * journal structures from interrupts.
886  */
887 
journal_current_handle(void)888 static inline handle_t *journal_current_handle(void)
889 {
890 	return current->journal_info;
891 }
892 
893 /* The journaling code user interface:
894  *
895  * Create and destroy handles
896  * Register buffer modifications against the current transaction.
897  */
898 
899 extern handle_t *journal_start(journal_t *, int nblocks);
900 extern int	 journal_restart (handle_t *, int nblocks);
901 extern int	 journal_extend (handle_t *, int nblocks);
902 extern int	 journal_get_write_access(handle_t *, struct buffer_head *);
903 extern int	 journal_get_create_access (handle_t *, struct buffer_head *);
904 extern int	 journal_get_undo_access(handle_t *, struct buffer_head *);
905 extern int	 journal_dirty_data (handle_t *, struct buffer_head *);
906 extern int	 journal_dirty_metadata (handle_t *, struct buffer_head *);
907 extern void	 journal_release_buffer (handle_t *, struct buffer_head *);
908 extern int	 journal_forget (handle_t *, struct buffer_head *);
909 extern void	 journal_sync_buffer (struct buffer_head *);
910 extern void	 journal_invalidatepage(journal_t *,
911 				struct page *, unsigned long);
912 extern int	 journal_try_to_free_buffers(journal_t *, struct page *, gfp_t);
913 extern int	 journal_stop(handle_t *);
914 extern int	 journal_flush (journal_t *);
915 extern void	 journal_lock_updates (journal_t *);
916 extern void	 journal_unlock_updates (journal_t *);
917 
918 extern journal_t * journal_init_dev(struct block_device *bdev,
919 				struct block_device *fs_dev,
920 				int start, int len, int bsize);
921 extern journal_t * journal_init_inode (struct inode *);
922 extern int	   journal_update_format (journal_t *);
923 extern int	   journal_check_used_features
924 		   (journal_t *, unsigned long, unsigned long, unsigned long);
925 extern int	   journal_check_available_features
926 		   (journal_t *, unsigned long, unsigned long, unsigned long);
927 extern int	   journal_set_features
928 		   (journal_t *, unsigned long, unsigned long, unsigned long);
929 extern int	   journal_create     (journal_t *);
930 extern int	   journal_load       (journal_t *journal);
931 extern int	   journal_destroy    (journal_t *);
932 extern int	   journal_recover    (journal_t *journal);
933 extern int	   journal_wipe       (journal_t *, int);
934 extern int	   journal_skip_recovery	(journal_t *);
935 extern void	   journal_update_superblock	(journal_t *, int);
936 extern void	   journal_abort      (journal_t *, int);
937 extern int	   journal_errno      (journal_t *);
938 extern void	   journal_ack_err    (journal_t *);
939 extern int	   journal_clear_err  (journal_t *);
940 extern int	   journal_bmap(journal_t *, unsigned long, unsigned long *);
941 extern int	   journal_force_commit(journal_t *);
942 
943 /*
944  * journal_head management
945  */
946 struct journal_head *journal_add_journal_head(struct buffer_head *bh);
947 struct journal_head *journal_grab_journal_head(struct buffer_head *bh);
948 void journal_remove_journal_head(struct buffer_head *bh);
949 void journal_put_journal_head(struct journal_head *jh);
950 
951 /*
952  * handle management
953  */
954 extern struct kmem_cache *jbd_handle_cache;
955 
jbd_alloc_handle(gfp_t gfp_flags)956 static inline handle_t *jbd_alloc_handle(gfp_t gfp_flags)
957 {
958 	return kmem_cache_alloc(jbd_handle_cache, gfp_flags);
959 }
960 
jbd_free_handle(handle_t * handle)961 static inline void jbd_free_handle(handle_t *handle)
962 {
963 	kmem_cache_free(jbd_handle_cache, handle);
964 }
965 
966 /* Primary revoke support */
967 #define JOURNAL_REVOKE_DEFAULT_HASH 256
968 extern int	   journal_init_revoke(journal_t *, int);
969 extern void	   journal_destroy_revoke_caches(void);
970 extern int	   journal_init_revoke_caches(void);
971 
972 extern void	   journal_destroy_revoke(journal_t *);
973 extern int	   journal_revoke (handle_t *,
974 				unsigned long, struct buffer_head *);
975 extern int	   journal_cancel_revoke(handle_t *, struct journal_head *);
976 extern void	   journal_write_revoke_records(journal_t *, transaction_t *);
977 
978 /* Recovery revoke support */
979 extern int	journal_set_revoke(journal_t *, unsigned long, tid_t);
980 extern int	journal_test_revoke(journal_t *, unsigned long, tid_t);
981 extern void	journal_clear_revoke(journal_t *);
982 extern void	journal_switch_revoke_table(journal_t *journal);
983 
984 /*
985  * The log thread user interface:
986  *
987  * Request space in the current transaction, and force transaction commit
988  * transitions on demand.
989  */
990 
991 int __log_space_left(journal_t *); /* Called with journal locked */
992 int log_start_commit(journal_t *journal, tid_t tid);
993 int __log_start_commit(journal_t *journal, tid_t tid);
994 int journal_start_commit(journal_t *journal, tid_t *tid);
995 int journal_force_commit_nested(journal_t *journal);
996 int log_wait_commit(journal_t *journal, tid_t tid);
997 int log_do_checkpoint(journal_t *journal);
998 
999 void __log_wait_for_space(journal_t *journal);
1000 extern void	__journal_drop_transaction(journal_t *, transaction_t *);
1001 extern int	cleanup_journal_tail(journal_t *);
1002 
1003 /* Debugging code only: */
1004 
1005 #define jbd_ENOSYS() \
1006 do {								           \
1007 	printk (KERN_ERR "JBD unimplemented function %s\n", __func__); \
1008 	current->state = TASK_UNINTERRUPTIBLE;			           \
1009 	schedule();						           \
1010 } while (1)
1011 
1012 /*
1013  * is_journal_abort
1014  *
1015  * Simple test wrapper function to test the JFS_ABORT state flag.  This
1016  * bit, when set, indicates that we have had a fatal error somewhere,
1017  * either inside the journaling layer or indicated to us by the client
1018  * (eg. ext3), and that we and should not commit any further
1019  * transactions.
1020  */
1021 
is_journal_aborted(journal_t * journal)1022 static inline int is_journal_aborted(journal_t *journal)
1023 {
1024 	return journal->j_flags & JFS_ABORT;
1025 }
1026 
is_handle_aborted(handle_t * handle)1027 static inline int is_handle_aborted(handle_t *handle)
1028 {
1029 	if (handle->h_aborted)
1030 		return 1;
1031 	return is_journal_aborted(handle->h_transaction->t_journal);
1032 }
1033 
journal_abort_handle(handle_t * handle)1034 static inline void journal_abort_handle(handle_t *handle)
1035 {
1036 	handle->h_aborted = 1;
1037 }
1038 
1039 #endif /* __KERNEL__   */
1040 
1041 /* Comparison functions for transaction IDs: perform comparisons using
1042  * modulo arithmetic so that they work over sequence number wraps. */
1043 
tid_gt(tid_t x,tid_t y)1044 static inline int tid_gt(tid_t x, tid_t y)
1045 {
1046 	int difference = (x - y);
1047 	return (difference > 0);
1048 }
1049 
tid_geq(tid_t x,tid_t y)1050 static inline int tid_geq(tid_t x, tid_t y)
1051 {
1052 	int difference = (x - y);
1053 	return (difference >= 0);
1054 }
1055 
1056 extern int journal_blocks_per_page(struct inode *inode);
1057 
1058 /*
1059  * Return the minimum number of blocks which must be free in the journal
1060  * before a new transaction may be started.  Must be called under j_state_lock.
1061  */
jbd_space_needed(journal_t * journal)1062 static inline int jbd_space_needed(journal_t *journal)
1063 {
1064 	int nblocks = journal->j_max_transaction_buffers;
1065 	if (journal->j_committing_transaction)
1066 		nblocks += journal->j_committing_transaction->
1067 					t_outstanding_credits;
1068 	return nblocks;
1069 }
1070 
1071 /*
1072  * Definitions which augment the buffer_head layer
1073  */
1074 
1075 /* journaling buffer types */
1076 #define BJ_None		0	/* Not journaled */
1077 #define BJ_SyncData	1	/* Normal data: flush before commit */
1078 #define BJ_Metadata	2	/* Normal journaled metadata */
1079 #define BJ_Forget	3	/* Buffer superseded by this transaction */
1080 #define BJ_IO		4	/* Buffer is for temporary IO use */
1081 #define BJ_Shadow	5	/* Buffer contents being shadowed to the log */
1082 #define BJ_LogCtl	6	/* Buffer contains log descriptors */
1083 #define BJ_Reserved	7	/* Buffer is reserved for access by journal */
1084 #define BJ_Locked	8	/* Locked for I/O during commit */
1085 #define BJ_Types	9
1086 
1087 extern int jbd_blocks_per_page(struct inode *inode);
1088 
1089 #ifdef __KERNEL__
1090 
1091 #define buffer_trace_init(bh)	do {} while (0)
1092 #define print_buffer_fields(bh)	do {} while (0)
1093 #define print_buffer_trace(bh)	do {} while (0)
1094 #define BUFFER_TRACE(bh, info)	do {} while (0)
1095 #define BUFFER_TRACE2(bh, bh2, info)	do {} while (0)
1096 #define JBUFFER_TRACE(jh, info)	do {} while (0)
1097 
1098 #endif	/* __KERNEL__ */
1099 
1100 #endif	/* _LINUX_JBD_H */
1101