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
34 #include <asm/semaphore.h>
35 #endif
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 int 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 extern void * __jbd_kmalloc (const char *where, size_t size, gfp_t flags, int retry);
75 extern void * jbd_slab_alloc(size_t size, gfp_t flags);
76 extern void jbd_slab_free(void *ptr, size_t size);
77
78 #define jbd_kmalloc(size, flags) \
79 __jbd_kmalloc(__FUNCTION__, (size), (flags), journal_oom_retry)
80 #define jbd_rep_kmalloc(size, flags) \
81 __jbd_kmalloc(__FUNCTION__, (size), (flags), 1)
82
83 #define JFS_MIN_JOURNAL_BLOCKS 1024
84
85 #ifdef __KERNEL__
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 JBD_ASSERTIONS
250 #ifdef JBD_ASSERTIONS
251 #define J_ASSERT(assert) \
252 do { \
253 if (!(assert)) { \
254 printk (KERN_EMERG \
255 "Assertion failure in %s() at %s:%d: \"%s\"\n", \
256 __FUNCTION__, __FILE__, __LINE__, # assert); \
257 BUG(); \
258 } \
259 } while (0)
260
261 #if defined(CONFIG_BUFFER_DEBUG)
262 void buffer_assertion_failure(struct buffer_head *bh);
263 #define J_ASSERT_BH(bh, expr) \
264 do { \
265 if (!(expr)) \
266 buffer_assertion_failure(bh); \
267 J_ASSERT(expr); \
268 } while (0)
269 #define J_ASSERT_JH(jh, expr) J_ASSERT_BH(jh2bh(jh), expr)
270 #else
271 #define J_ASSERT_BH(bh, expr) J_ASSERT(expr)
272 #define J_ASSERT_JH(jh, expr) J_ASSERT(expr)
273 #endif
274
275 #else
276 #define J_ASSERT(assert) do { } while (0)
277 #endif /* JBD_ASSERTIONS */
278
279 #if defined(JBD_PARANOID_IOFAIL)
280 #define J_EXPECT(expr, why...) J_ASSERT(expr)
281 #define J_EXPECT_BH(bh, expr, why...) J_ASSERT_BH(bh, expr)
282 #define J_EXPECT_JH(jh, expr, why...) J_ASSERT_JH(jh, expr)
283 #else
284 #define __journal_expect(expr, why...) \
285 ({ \
286 int val = (expr); \
287 if (!val) { \
288 printk(KERN_ERR \
289 "EXT3-fs unexpected failure: %s;\n",# expr); \
290 printk(KERN_ERR why "\n"); \
291 } \
292 val; \
293 })
294 #define J_EXPECT(expr, why...) __journal_expect(expr, ## why)
295 #define J_EXPECT_BH(bh, expr, why...) __journal_expect(expr, ## why)
296 #define J_EXPECT_JH(jh, expr, why...) __journal_expect(expr, ## why)
297 #endif
298
299 enum jbd_state_bits {
300 BH_JBD /* Has an attached ext3 journal_head */
301 = BH_PrivateStart,
302 BH_JWrite, /* Being written to log (@@@ DEBUGGING) */
303 BH_Freed, /* Has been freed (truncated) */
304 BH_Revoked, /* Has been revoked from the log */
305 BH_RevokeValid, /* Revoked flag is valid */
306 BH_JBDDirty, /* Is dirty but journaled */
307 BH_State, /* Pins most journal_head state */
308 BH_JournalHead, /* Pins bh->b_private and jh->b_bh */
309 BH_Unshadow, /* Dummy bit, for BJ_Shadow wakeup filtering */
310 };
311
BUFFER_FNS(JBD,jbd)312 BUFFER_FNS(JBD, jbd)
313 BUFFER_FNS(JWrite, jwrite)
314 BUFFER_FNS(JBDDirty, jbddirty)
315 TAS_BUFFER_FNS(JBDDirty, jbddirty)
316 BUFFER_FNS(Revoked, revoked)
317 TAS_BUFFER_FNS(Revoked, revoked)
318 BUFFER_FNS(RevokeValid, revokevalid)
319 TAS_BUFFER_FNS(RevokeValid, revokevalid)
320 BUFFER_FNS(Freed, freed)
321
322 static inline struct buffer_head *jh2bh(struct journal_head *jh)
323 {
324 return jh->b_bh;
325 }
326
bh2jh(struct buffer_head * bh)327 static inline struct journal_head *bh2jh(struct buffer_head *bh)
328 {
329 return bh->b_private;
330 }
331
jbd_lock_bh_state(struct buffer_head * bh)332 static inline void jbd_lock_bh_state(struct buffer_head *bh)
333 {
334 bit_spin_lock(BH_State, &bh->b_state);
335 }
336
jbd_trylock_bh_state(struct buffer_head * bh)337 static inline int jbd_trylock_bh_state(struct buffer_head *bh)
338 {
339 return bit_spin_trylock(BH_State, &bh->b_state);
340 }
341
jbd_is_locked_bh_state(struct buffer_head * bh)342 static inline int jbd_is_locked_bh_state(struct buffer_head *bh)
343 {
344 return bit_spin_is_locked(BH_State, &bh->b_state);
345 }
346
jbd_unlock_bh_state(struct buffer_head * bh)347 static inline void jbd_unlock_bh_state(struct buffer_head *bh)
348 {
349 bit_spin_unlock(BH_State, &bh->b_state);
350 }
351
jbd_lock_bh_journal_head(struct buffer_head * bh)352 static inline void jbd_lock_bh_journal_head(struct buffer_head *bh)
353 {
354 bit_spin_lock(BH_JournalHead, &bh->b_state);
355 }
356
jbd_unlock_bh_journal_head(struct buffer_head * bh)357 static inline void jbd_unlock_bh_journal_head(struct buffer_head *bh)
358 {
359 bit_spin_unlock(BH_JournalHead, &bh->b_state);
360 }
361
362 struct jbd_revoke_table_s;
363
364 /**
365 * struct handle_s - The handle_s type is the concrete type associated with
366 * handle_t.
367 * @h_transaction: Which compound transaction is this update a part of?
368 * @h_buffer_credits: Number of remaining buffers we are allowed to dirty.
369 * @h_ref: Reference count on this handle
370 * @h_err: Field for caller's use to track errors through large fs operations
371 * @h_sync: flag for sync-on-close
372 * @h_jdata: flag to force data journaling
373 * @h_aborted: flag indicating fatal error on handle
374 **/
375
376 /* Docbook can't yet cope with the bit fields, but will leave the documentation
377 * in so it can be fixed later.
378 */
379
380 struct handle_s
381 {
382 /* Which compound transaction is this update a part of? */
383 transaction_t *h_transaction;
384
385 /* Number of remaining buffers we are allowed to dirty: */
386 int h_buffer_credits;
387
388 /* Reference count on this handle */
389 int h_ref;
390
391 /* Field for caller's use to track errors through large fs */
392 /* operations */
393 int h_err;
394
395 /* Flags [no locking] */
396 unsigned int h_sync: 1; /* sync-on-close */
397 unsigned int h_jdata: 1; /* force data journaling */
398 unsigned int h_aborted: 1; /* fatal error on handle */
399 };
400
401
402 /* The transaction_t type is the guts of the journaling mechanism. It
403 * tracks a compound transaction through its various states:
404 *
405 * RUNNING: accepting new updates
406 * LOCKED: Updates still running but we don't accept new ones
407 * RUNDOWN: Updates are tidying up but have finished requesting
408 * new buffers to modify (state not used for now)
409 * FLUSH: All updates complete, but we are still writing to disk
410 * COMMIT: All data on disk, writing commit record
411 * FINISHED: We still have to keep the transaction for checkpointing.
412 *
413 * The transaction keeps track of all of the buffers modified by a
414 * running transaction, and all of the buffers committed but not yet
415 * flushed to home for finished transactions.
416 */
417
418 /*
419 * Lock ranking:
420 *
421 * j_list_lock
422 * ->jbd_lock_bh_journal_head() (This is "innermost")
423 *
424 * j_state_lock
425 * ->jbd_lock_bh_state()
426 *
427 * jbd_lock_bh_state()
428 * ->j_list_lock
429 *
430 * j_state_lock
431 * ->t_handle_lock
432 *
433 * j_state_lock
434 * ->j_list_lock (journal_unmap_buffer)
435 *
436 */
437
438 struct transaction_s
439 {
440 /* Pointer to the journal for this transaction. [no locking] */
441 journal_t *t_journal;
442
443 /* Sequence number for this transaction [no locking] */
444 tid_t t_tid;
445
446 /*
447 * Transaction's current state
448 * [no locking - only kjournald alters this]
449 * FIXME: needs barriers
450 * KLUDGE: [use j_state_lock]
451 */
452 enum {
453 T_RUNNING,
454 T_LOCKED,
455 T_RUNDOWN,
456 T_FLUSH,
457 T_COMMIT,
458 T_FINISHED
459 } t_state;
460
461 /*
462 * Where in the log does this transaction's commit start? [no locking]
463 */
464 unsigned long t_log_start;
465
466 /* Number of buffers on the t_buffers list [j_list_lock] */
467 int t_nr_buffers;
468
469 /*
470 * Doubly-linked circular list of all buffers reserved but not yet
471 * modified by this transaction [j_list_lock]
472 */
473 struct journal_head *t_reserved_list;
474
475 /*
476 * Doubly-linked circular list of all buffers under writeout during
477 * commit [j_list_lock]
478 */
479 struct journal_head *t_locked_list;
480
481 /*
482 * Doubly-linked circular list of all metadata buffers owned by this
483 * transaction [j_list_lock]
484 */
485 struct journal_head *t_buffers;
486
487 /*
488 * Doubly-linked circular list of all data buffers still to be
489 * flushed before this transaction can be committed [j_list_lock]
490 */
491 struct journal_head *t_sync_datalist;
492
493 /*
494 * Doubly-linked circular list of all forget buffers (superseded
495 * buffers which we can un-checkpoint once this transaction commits)
496 * [j_list_lock]
497 */
498 struct journal_head *t_forget;
499
500 /*
501 * Doubly-linked circular list of all buffers still to be flushed before
502 * this transaction can be checkpointed. [j_list_lock]
503 */
504 struct journal_head *t_checkpoint_list;
505
506 /*
507 * Doubly-linked circular list of all buffers submitted for IO while
508 * checkpointing. [j_list_lock]
509 */
510 struct journal_head *t_checkpoint_io_list;
511
512 /*
513 * Doubly-linked circular list of temporary buffers currently undergoing
514 * IO in the log [j_list_lock]
515 */
516 struct journal_head *t_iobuf_list;
517
518 /*
519 * Doubly-linked circular list of metadata buffers being shadowed by log
520 * IO. The IO buffers on the iobuf list and the shadow buffers on this
521 * list match each other one for one at all times. [j_list_lock]
522 */
523 struct journal_head *t_shadow_list;
524
525 /*
526 * Doubly-linked circular list of control buffers being written to the
527 * log. [j_list_lock]
528 */
529 struct journal_head *t_log_list;
530
531 /*
532 * Protects info related to handles
533 */
534 spinlock_t t_handle_lock;
535
536 /*
537 * Number of outstanding updates running on this transaction
538 * [t_handle_lock]
539 */
540 int t_updates;
541
542 /*
543 * Number of buffers reserved for use by all handles in this transaction
544 * handle but not yet modified. [t_handle_lock]
545 */
546 int t_outstanding_credits;
547
548 /*
549 * Forward and backward links for the circular list of all transactions
550 * awaiting checkpoint. [j_list_lock]
551 */
552 transaction_t *t_cpnext, *t_cpprev;
553
554 /*
555 * When will the transaction expire (become due for commit), in jiffies?
556 * [no locking]
557 */
558 unsigned long t_expires;
559
560 /*
561 * How many handles used this transaction? [t_handle_lock]
562 */
563 int t_handle_count;
564
565 };
566
567 /**
568 * struct journal_s - The journal_s type is the concrete type associated with
569 * journal_t.
570 * @j_flags: General journaling state flags
571 * @j_errno: Is there an outstanding uncleared error on the journal (from a
572 * prior abort)?
573 * @j_sb_buffer: First part of superblock buffer
574 * @j_superblock: Second part of superblock buffer
575 * @j_format_version: Version of the superblock format
576 * @j_state_lock: Protect the various scalars in the journal
577 * @j_barrier_count: Number of processes waiting to create a barrier lock
578 * @j_barrier: The barrier lock itself
579 * @j_running_transaction: The current running transaction..
580 * @j_committing_transaction: the transaction we are pushing to disk
581 * @j_checkpoint_transactions: a linked circular list of all transactions
582 * waiting for checkpointing
583 * @j_wait_transaction_locked: Wait queue for waiting for a locked transaction
584 * to start committing, or for a barrier lock to be released
585 * @j_wait_logspace: Wait queue for waiting for checkpointing to complete
586 * @j_wait_done_commit: Wait queue for waiting for commit to complete
587 * @j_wait_checkpoint: Wait queue to trigger checkpointing
588 * @j_wait_commit: Wait queue to trigger commit
589 * @j_wait_updates: Wait queue to wait for updates to complete
590 * @j_checkpoint_mutex: Mutex for locking against concurrent checkpoints
591 * @j_head: Journal head - identifies the first unused block in the journal
592 * @j_tail: Journal tail - identifies the oldest still-used block in the
593 * journal.
594 * @j_free: Journal free - how many free blocks are there in the journal?
595 * @j_first: The block number of the first usable block
596 * @j_last: The block number one beyond the last usable block
597 * @j_dev: Device where we store the journal
598 * @j_blocksize: blocksize for the location where we store the journal.
599 * @j_blk_offset: starting block offset for into the device where we store the
600 * journal
601 * @j_fs_dev: Device which holds the client fs. For internal journal this will
602 * be equal to j_dev
603 * @j_maxlen: Total maximum capacity of the journal region on disk.
604 * @j_list_lock: Protects the buffer lists and internal buffer state.
605 * @j_inode: Optional inode where we store the journal. If present, all journal
606 * block numbers are mapped into this inode via bmap().
607 * @j_tail_sequence: Sequence number of the oldest transaction in the log
608 * @j_transaction_sequence: Sequence number of the next transaction to grant
609 * @j_commit_sequence: Sequence number of the most recently committed
610 * transaction
611 * @j_commit_request: Sequence number of the most recent transaction wanting
612 * commit
613 * @j_uuid: Uuid of client object.
614 * @j_task: Pointer to the current commit thread for this journal
615 * @j_max_transaction_buffers: Maximum number of metadata buffers to allow in a
616 * single compound commit transaction
617 * @j_commit_interval: What is the maximum transaction lifetime before we begin
618 * a commit?
619 * @j_commit_timer: The timer used to wakeup the commit thread
620 * @j_revoke_lock: Protect the revoke table
621 * @j_revoke: The revoke table - maintains the list of revoked blocks in the
622 * current transaction.
623 * @j_revoke_table: alternate revoke tables for j_revoke
624 * @j_wbuf: array of buffer_heads for journal_commit_transaction
625 * @j_wbufsize: maximum number of buffer_heads allowed in j_wbuf, the
626 * number that will fit in j_blocksize
627 * @j_last_sync_writer: most recent pid which did a synchronous write
628 * @j_private: An opaque pointer to fs-private information.
629 */
630
631 struct journal_s
632 {
633 /* General journaling state flags [j_state_lock] */
634 unsigned long j_flags;
635
636 /*
637 * Is there an outstanding uncleared error on the journal (from a prior
638 * abort)? [j_state_lock]
639 */
640 int j_errno;
641
642 /* The superblock buffer */
643 struct buffer_head *j_sb_buffer;
644 journal_superblock_t *j_superblock;
645
646 /* Version of the superblock format */
647 int j_format_version;
648
649 /*
650 * Protect the various scalars in the journal
651 */
652 spinlock_t j_state_lock;
653
654 /*
655 * Number of processes waiting to create a barrier lock [j_state_lock]
656 */
657 int j_barrier_count;
658
659 /* The barrier lock itself */
660 struct mutex j_barrier;
661
662 /*
663 * Transactions: The current running transaction...
664 * [j_state_lock] [caller holding open handle]
665 */
666 transaction_t *j_running_transaction;
667
668 /*
669 * the transaction we are pushing to disk
670 * [j_state_lock] [caller holding open handle]
671 */
672 transaction_t *j_committing_transaction;
673
674 /*
675 * ... and a linked circular list of all transactions waiting for
676 * checkpointing. [j_list_lock]
677 */
678 transaction_t *j_checkpoint_transactions;
679
680 /*
681 * Wait queue for waiting for a locked transaction to start committing,
682 * or for a barrier lock to be released
683 */
684 wait_queue_head_t j_wait_transaction_locked;
685
686 /* Wait queue for waiting for checkpointing to complete */
687 wait_queue_head_t j_wait_logspace;
688
689 /* Wait queue for waiting for commit to complete */
690 wait_queue_head_t j_wait_done_commit;
691
692 /* Wait queue to trigger checkpointing */
693 wait_queue_head_t j_wait_checkpoint;
694
695 /* Wait queue to trigger commit */
696 wait_queue_head_t j_wait_commit;
697
698 /* Wait queue to wait for updates to complete */
699 wait_queue_head_t j_wait_updates;
700
701 /* Semaphore for locking against concurrent checkpoints */
702 struct mutex j_checkpoint_mutex;
703
704 /*
705 * Journal head: identifies the first unused block in the journal.
706 * [j_state_lock]
707 */
708 unsigned long j_head;
709
710 /*
711 * Journal tail: identifies the oldest still-used block in the journal.
712 * [j_state_lock]
713 */
714 unsigned long j_tail;
715
716 /*
717 * Journal free: how many free blocks are there in the journal?
718 * [j_state_lock]
719 */
720 unsigned long j_free;
721
722 /*
723 * Journal start and end: the block numbers of the first usable block
724 * and one beyond the last usable block in the journal. [j_state_lock]
725 */
726 unsigned long j_first;
727 unsigned long j_last;
728
729 /*
730 * Device, blocksize and starting block offset for the location where we
731 * store the journal.
732 */
733 struct block_device *j_dev;
734 int j_blocksize;
735 unsigned int j_blk_offset;
736
737 /*
738 * Device which holds the client fs. For internal journal this will be
739 * equal to j_dev.
740 */
741 struct block_device *j_fs_dev;
742
743 /* Total maximum capacity of the journal region on disk. */
744 unsigned int j_maxlen;
745
746 /*
747 * Protects the buffer lists and internal buffer state.
748 */
749 spinlock_t j_list_lock;
750
751 /* Optional inode where we store the journal. If present, all */
752 /* journal block numbers are mapped into this inode via */
753 /* bmap(). */
754 struct inode *j_inode;
755
756 /*
757 * Sequence number of the oldest transaction in the log [j_state_lock]
758 */
759 tid_t j_tail_sequence;
760
761 /*
762 * Sequence number of the next transaction to grant [j_state_lock]
763 */
764 tid_t j_transaction_sequence;
765
766 /*
767 * Sequence number of the most recently committed transaction
768 * [j_state_lock].
769 */
770 tid_t j_commit_sequence;
771
772 /*
773 * Sequence number of the most recent transaction wanting commit
774 * [j_state_lock]
775 */
776 tid_t j_commit_request;
777
778 /*
779 * Journal uuid: identifies the object (filesystem, LVM volume etc)
780 * backed by this journal. This will eventually be replaced by an array
781 * of uuids, allowing us to index multiple devices within a single
782 * journal and to perform atomic updates across them.
783 */
784 __u8 j_uuid[16];
785
786 /* Pointer to the current commit thread for this journal */
787 struct task_struct *j_task;
788
789 /*
790 * Maximum number of metadata buffers to allow in a single compound
791 * commit transaction
792 */
793 int j_max_transaction_buffers;
794
795 /*
796 * What is the maximum transaction lifetime before we begin a commit?
797 */
798 unsigned long j_commit_interval;
799
800 /* The timer used to wakeup the commit thread: */
801 struct timer_list j_commit_timer;
802
803 /*
804 * The revoke table: maintains the list of revoked blocks in the
805 * current transaction. [j_revoke_lock]
806 */
807 spinlock_t j_revoke_lock;
808 struct jbd_revoke_table_s *j_revoke;
809 struct jbd_revoke_table_s *j_revoke_table[2];
810
811 /*
812 * array of bhs for journal_commit_transaction
813 */
814 struct buffer_head **j_wbuf;
815 int j_wbufsize;
816
817 pid_t j_last_sync_writer;
818
819 /*
820 * An opaque pointer to fs-private information. ext3 puts its
821 * superblock pointer here
822 */
823 void *j_private;
824 };
825
826 /*
827 * Journal flag definitions
828 */
829 #define JFS_UNMOUNT 0x001 /* Journal thread is being destroyed */
830 #define JFS_ABORT 0x002 /* Journaling has been aborted for errors. */
831 #define JFS_ACK_ERR 0x004 /* The errno in the sb has been acked */
832 #define JFS_FLUSHED 0x008 /* The journal superblock has been flushed */
833 #define JFS_LOADED 0x010 /* The journal superblock has been loaded */
834 #define JFS_BARRIER 0x020 /* Use IDE barriers */
835
836 /*
837 * Function declarations for the journaling transaction and buffer
838 * management
839 */
840
841 /* Filing buffers */
842 extern void __journal_temp_unlink_buffer(struct journal_head *jh);
843 extern void journal_unfile_buffer(journal_t *, struct journal_head *);
844 extern void __journal_unfile_buffer(struct journal_head *);
845 extern void __journal_refile_buffer(struct journal_head *);
846 extern void journal_refile_buffer(journal_t *, struct journal_head *);
847 extern void __journal_file_buffer(struct journal_head *, transaction_t *, int);
848 extern void __journal_free_buffer(struct journal_head *bh);
849 extern void journal_file_buffer(struct journal_head *, transaction_t *, int);
850 extern void __journal_clean_data_list(transaction_t *transaction);
851
852 /* Log buffer allocation */
853 extern struct journal_head * journal_get_descriptor_buffer(journal_t *);
854 int journal_next_log_block(journal_t *, unsigned long *);
855
856 /* Commit management */
857 extern void journal_commit_transaction(journal_t *);
858
859 /* Checkpoint list management */
860 int __journal_clean_checkpoint_list(journal_t *journal);
861 int __journal_remove_checkpoint(struct journal_head *);
862 void __journal_insert_checkpoint(struct journal_head *, transaction_t *);
863
864 /* Buffer IO */
865 extern int
866 journal_write_metadata_buffer(transaction_t *transaction,
867 struct journal_head *jh_in,
868 struct journal_head **jh_out,
869 int blocknr);
870
871 /* Transaction locking */
872 extern void __wait_on_journal (journal_t *);
873
874 /*
875 * Journal locking.
876 *
877 * We need to lock the journal during transaction state changes so that nobody
878 * ever tries to take a handle on the running transaction while we are in the
879 * middle of moving it to the commit phase. j_state_lock does this.
880 *
881 * Note that the locking is completely interrupt unsafe. We never touch
882 * journal structures from interrupts.
883 */
884
journal_current_handle(void)885 static inline handle_t *journal_current_handle(void)
886 {
887 return current->journal_info;
888 }
889
890 /* The journaling code user interface:
891 *
892 * Create and destroy handles
893 * Register buffer modifications against the current transaction.
894 */
895
896 extern handle_t *journal_start(journal_t *, int nblocks);
897 extern int journal_restart (handle_t *, int nblocks);
898 extern int journal_extend (handle_t *, int nblocks);
899 extern int journal_get_write_access(handle_t *, struct buffer_head *);
900 extern int journal_get_create_access (handle_t *, struct buffer_head *);
901 extern int journal_get_undo_access(handle_t *, struct buffer_head *);
902 extern int journal_dirty_data (handle_t *, struct buffer_head *);
903 extern int journal_dirty_metadata (handle_t *, struct buffer_head *);
904 extern void journal_release_buffer (handle_t *, struct buffer_head *);
905 extern int journal_forget (handle_t *, struct buffer_head *);
906 extern void journal_sync_buffer (struct buffer_head *);
907 extern void journal_invalidatepage(journal_t *,
908 struct page *, unsigned long);
909 extern int journal_try_to_free_buffers(journal_t *, struct page *, gfp_t);
910 extern int journal_stop(handle_t *);
911 extern int journal_flush (journal_t *);
912 extern void journal_lock_updates (journal_t *);
913 extern void journal_unlock_updates (journal_t *);
914
915 extern journal_t * journal_init_dev(struct block_device *bdev,
916 struct block_device *fs_dev,
917 int start, int len, int bsize);
918 extern journal_t * journal_init_inode (struct inode *);
919 extern int journal_update_format (journal_t *);
920 extern int journal_check_used_features
921 (journal_t *, unsigned long, unsigned long, unsigned long);
922 extern int journal_check_available_features
923 (journal_t *, unsigned long, unsigned long, unsigned long);
924 extern int journal_set_features
925 (journal_t *, unsigned long, unsigned long, unsigned long);
926 extern int journal_create (journal_t *);
927 extern int journal_load (journal_t *journal);
928 extern void journal_destroy (journal_t *);
929 extern int journal_recover (journal_t *journal);
930 extern int journal_wipe (journal_t *, int);
931 extern int journal_skip_recovery (journal_t *);
932 extern void journal_update_superblock (journal_t *, int);
933 extern void __journal_abort_hard (journal_t *);
934 extern void journal_abort (journal_t *, int);
935 extern int journal_errno (journal_t *);
936 extern void journal_ack_err (journal_t *);
937 extern int journal_clear_err (journal_t *);
938 extern int journal_bmap(journal_t *, unsigned long, unsigned long *);
939 extern int journal_force_commit(journal_t *);
940
941 /*
942 * journal_head management
943 */
944 struct journal_head *journal_add_journal_head(struct buffer_head *bh);
945 struct journal_head *journal_grab_journal_head(struct buffer_head *bh);
946 void journal_remove_journal_head(struct buffer_head *bh);
947 void journal_put_journal_head(struct journal_head *jh);
948
949 /*
950 * handle management
951 */
952 extern kmem_cache_t *jbd_handle_cache;
953
jbd_alloc_handle(gfp_t gfp_flags)954 static inline handle_t *jbd_alloc_handle(gfp_t gfp_flags)
955 {
956 return kmem_cache_alloc(jbd_handle_cache, gfp_flags);
957 }
958
jbd_free_handle(handle_t * handle)959 static inline void jbd_free_handle(handle_t *handle)
960 {
961 kmem_cache_free(jbd_handle_cache, handle);
962 }
963
964 /* Primary revoke support */
965 #define JOURNAL_REVOKE_DEFAULT_HASH 256
966 extern int journal_init_revoke(journal_t *, int);
967 extern void journal_destroy_revoke_caches(void);
968 extern int journal_init_revoke_caches(void);
969
970 extern void journal_destroy_revoke(journal_t *);
971 extern int journal_revoke (handle_t *,
972 unsigned long, struct buffer_head *);
973 extern int journal_cancel_revoke(handle_t *, struct journal_head *);
974 extern void journal_write_revoke_records(journal_t *, transaction_t *);
975
976 /* Recovery revoke support */
977 extern int journal_set_revoke(journal_t *, unsigned long, tid_t);
978 extern int journal_test_revoke(journal_t *, unsigned long, tid_t);
979 extern void journal_clear_revoke(journal_t *);
980 extern void journal_brelse_array(struct buffer_head *b[], int n);
981 extern void journal_switch_revoke_table(journal_t *journal);
982
983 /*
984 * The log thread user interface:
985 *
986 * Request space in the current transaction, and force transaction commit
987 * transitions on demand.
988 */
989
990 int __log_space_left(journal_t *); /* Called with journal locked */
991 int log_start_commit(journal_t *journal, tid_t tid);
992 int __log_start_commit(journal_t *journal, tid_t tid);
993 int journal_start_commit(journal_t *journal, tid_t *tid);
994 int journal_force_commit_nested(journal_t *journal);
995 int log_wait_commit(journal_t *journal, tid_t tid);
996 int log_do_checkpoint(journal_t *journal);
997
998 void __log_wait_for_space(journal_t *journal);
999 extern void __journal_drop_transaction(journal_t *, transaction_t *);
1000 extern int cleanup_journal_tail(journal_t *);
1001
1002 /* Debugging code only: */
1003
1004 #define jbd_ENOSYS() \
1005 do { \
1006 printk (KERN_ERR "JBD unimplemented function %s\n", __FUNCTION__); \
1007 current->state = TASK_UNINTERRUPTIBLE; \
1008 schedule(); \
1009 } while (1)
1010
1011 /*
1012 * is_journal_abort
1013 *
1014 * Simple test wrapper function to test the JFS_ABORT state flag. This
1015 * bit, when set, indicates that we have had a fatal error somewhere,
1016 * either inside the journaling layer or indicated to us by the client
1017 * (eg. ext3), and that we and should not commit any further
1018 * transactions.
1019 */
1020
is_journal_aborted(journal_t * journal)1021 static inline int is_journal_aborted(journal_t *journal)
1022 {
1023 return journal->j_flags & JFS_ABORT;
1024 }
1025
is_handle_aborted(handle_t * handle)1026 static inline int is_handle_aborted(handle_t *handle)
1027 {
1028 if (handle->h_aborted)
1029 return 1;
1030 return is_journal_aborted(handle->h_transaction->t_journal);
1031 }
1032
journal_abort_handle(handle_t * handle)1033 static inline void journal_abort_handle(handle_t *handle)
1034 {
1035 handle->h_aborted = 1;
1036 }
1037
1038 #endif /* __KERNEL__ */
1039
1040 /* Comparison functions for transaction IDs: perform comparisons using
1041 * modulo arithmetic so that they work over sequence number wraps. */
1042
tid_gt(tid_t x,tid_t y)1043 static inline int tid_gt(tid_t x, tid_t y)
1044 {
1045 int difference = (x - y);
1046 return (difference > 0);
1047 }
1048
tid_geq(tid_t x,tid_t y)1049 static inline int tid_geq(tid_t x, tid_t y)
1050 {
1051 int difference = (x - y);
1052 return (difference >= 0);
1053 }
1054
1055 extern int journal_blocks_per_page(struct inode *inode);
1056
1057 /*
1058 * Return the minimum number of blocks which must be free in the journal
1059 * before a new transaction may be started. Must be called under j_state_lock.
1060 */
jbd_space_needed(journal_t * journal)1061 static inline int jbd_space_needed(journal_t *journal)
1062 {
1063 int nblocks = journal->j_max_transaction_buffers;
1064 if (journal->j_committing_transaction)
1065 nblocks += journal->j_committing_transaction->
1066 t_outstanding_credits;
1067 return nblocks;
1068 }
1069
1070 /*
1071 * Definitions which augment the buffer_head layer
1072 */
1073
1074 /* journaling buffer types */
1075 #define BJ_None 0 /* Not journaled */
1076 #define BJ_SyncData 1 /* Normal data: flush before commit */
1077 #define BJ_Metadata 2 /* Normal journaled metadata */
1078 #define BJ_Forget 3 /* Buffer superseded by this transaction */
1079 #define BJ_IO 4 /* Buffer is for temporary IO use */
1080 #define BJ_Shadow 5 /* Buffer contents being shadowed to the log */
1081 #define BJ_LogCtl 6 /* Buffer contains log descriptors */
1082 #define BJ_Reserved 7 /* Buffer is reserved for access by journal */
1083 #define BJ_Locked 8 /* Locked for I/O during commit */
1084 #define BJ_Types 9
1085
1086 extern int jbd_blocks_per_page(struct inode *inode);
1087
1088 #ifdef __KERNEL__
1089
1090 #define buffer_trace_init(bh) do {} while (0)
1091 #define print_buffer_fields(bh) do {} while (0)
1092 #define print_buffer_trace(bh) do {} while (0)
1093 #define BUFFER_TRACE(bh, info) do {} while (0)
1094 #define BUFFER_TRACE2(bh, bh2, info) do {} while (0)
1095 #define JBUFFER_TRACE(jh, info) do {} while (0)
1096
1097 #endif /* __KERNEL__ */
1098
1099 #endif /* _LINUX_JBD_H */
1100