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