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