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