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