lib/ext2fs/kernel-jbd.h

   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/journal-head.h>
  29 #include <linux/stddef.h>
  30 #include <asm/semaphore.h>
  31 #endif
  32
  33 #define journal_oom_retry 1
  34
  35 #ifdef __STDC__
  36 #ifdef CONFIG_JBD_DEBUG
  37 /*
  38  * Define JBD_EXPENSIVE_CHECKING to enable more expensive internal
  39  * consistency checks.  By default we don't do this unless
  40  * CONFIG_JBD_DEBUG is on.
  41  */
  42 #define JBD_EXPENSIVE_CHECKING
  43 extern int journal_enable_debug;
  44
  45 #define jbd_debug(n, f, a...)                                           \
  46         do {                                                            \
  47                 if ((n) <= journal_enable_debug) {                      \
  48                         printk (KERN_DEBUG "(%s, %d): %s: ",            \
  49                                 __FILE__, __LINE__, __FUNCTION__);      \
  50                         printk (f, ## a);                               \
  51                 }                                                       \
  52         } while (0)
  53 #else
  54 #define jbd_debug(f, a...)      /**/
  55 #endif
  56 #else
  57 #define jbd_debug(x)            /* AIX doesn't do STDC */
  58 #endif
  59
  60 extern void * __jbd_kmalloc (char *where, size_t size, int flags, int retry);
  61 #define jbd_kmalloc(size, flags) \
  62         __jbd_kmalloc(__FUNCTION__, (size), (flags), journal_oom_retry)
  63 #define jbd_rep_kmalloc(size, flags) \
  64         __jbd_kmalloc(__FUNCTION__, (size), (flags), 1)
  65
  66 #define JFS_MIN_JOURNAL_BLOCKS 1024
  67
  68 #ifdef __KERNEL__
  69 typedef struct handle_s         handle_t;       /* Atomic operation type */
  70 typedef struct journal_s        journal_t;      /* Journal control structure */
  71 #endif
  72
  73 /*
  74  * Internal structures used by the logging mechanism:
  75  */
  76
  77 #define JFS_MAGIC_NUMBER 0xc03b3998U /* The first 4 bytes of /dev/random! */
  78
  79 /*
  80  * On-disk structures
  81  */
  82
  83 /*
  84  * Descriptor block types:
  85  */
  86
  87 #define JFS_DESCRIPTOR_BLOCK    1
  88 #define JFS_COMMIT_BLOCK        2
  89 #define JFS_SUPERBLOCK_V1       3
  90 #define JFS_SUPERBLOCK_V2       4
  91 #define JFS_REVOKE_BLOCK        5
  92
  93 /*
  94  * Standard header for all descriptor blocks:
  95  */
  96 typedef struct journal_header_s
  97 {
  98         __u32           h_magic;
  99         __u32           h_blocktype;
 100         __u32           h_sequence;
 101 } journal_header_t;
 102
 103
 104 /*
 105  * The block tag: used to describe a single buffer in the journal
 106  */
 107 typedef struct journal_block_tag_s
 108 {
 109         __u32           t_blocknr;      /* The on-disk block number */
 110         __u32           t_flags;        /* See below */
 111 } journal_block_tag_t;
 112
 113 /*
 114  * The revoke descriptor: used on disk to describe a series of blocks to
 115  * be revoked from the log
 116  */
 117 typedef struct journal_revoke_header_s
 118 {
 119         journal_header_t r_header;
 120         int              r_count;       /* Count of bytes used in the block */
 121 } journal_revoke_header_t;
 122
 123
 124 /* Definitions for the journal tag flags word: */
 125 #define JFS_FLAG_ESCAPE         1       /* on-disk block is escaped */
 126 #define JFS_FLAG_SAME_UUID      2       /* block has same uuid as previous */
 127 #define JFS_FLAG_DELETED        4       /* block deleted by this transaction */
 128 #define JFS_FLAG_LAST_TAG       8       /* last tag in this descriptor block */
 129
 130
 131 /*
 132  * The journal superblock.  All fields are in big-endian byte order.
 133  */
 134 typedef struct journal_superblock_s
 135 {
 136 /* 0x0000 */
 137         journal_header_t s_header;
 138
 139 /* 0x000C */
 140         /* Static information describing the journal */
 141         __u32   s_blocksize;            /* journal device blocksize */
 142         __u32   s_maxlen;               /* total blocks in journal file */
 143         __u32   s_first;                /* first block of log information */
 144
 145 /* 0x0018 */
 146         /* Dynamic information describing the current state of the log */
 147         __u32   s_sequence;             /* first commit ID expected in log */
 148         __u32   s_start;                /* blocknr of start of log */
 149
 150 /* 0x0020 */
 151         /* Error value, as set by journal_abort(). */
 152         __s32   s_errno;
 153
 154 /* 0x0024 */
 155         /* Remaining fields are only valid in a version-2 superblock */
 156         __u32   s_feature_compat;       /* compatible feature set */
 157         __u32   s_feature_incompat;     /* incompatible feature set */
 158         __u32   s_feature_ro_compat;    /* readonly-compatible feature set */
 159 /* 0x0030 */
 160         __u8    s_uuid[16];             /* 128-bit uuid for journal */
 161
 162 /* 0x0040 */
 163         __u32   s_nr_users;             /* Nr of filesystems sharing log */
 164
 165         __u32   s_dynsuper;             /* Blocknr of dynamic superblock copy*/
 166
 167 /* 0x0048 */
 168         __u32   s_max_transaction;      /* Limit of journal blocks per trans.*/
 169         __u32   s_max_trans_data;       /* Limit of data blocks per trans. */
 170
 171 /* 0x0050 */
 172         __u32   s_padding[44];
 173
 174 /* 0x0100 */
 175         __u8    s_users[16*48];         /* ids of all fs'es sharing the log */
 176 /* 0x0400 */
 177 } journal_superblock_t;
 178
 179 #define JFS_HAS_COMPAT_FEATURE(j,mask)                                  \
 180         ((j)->j_format_version >= 2 &&                                  \
 181          ((j)->j_superblock->s_feature_compat & cpu_to_be32((mask))))
 182 #define JFS_HAS_RO_COMPAT_FEATURE(j,mask)                               \
 183         ((j)->j_format_version >= 2 &&                                  \
 184          ((j)->j_superblock->s_feature_ro_compat & cpu_to_be32((mask))))
 185 #define JFS_HAS_INCOMPAT_FEATURE(j,mask)                                \
 186         ((j)->j_format_version >= 2 &&                                  \
 187          ((j)->j_superblock->s_feature_incompat & cpu_to_be32((mask))))
 188
 189 #define JFS_FEATURE_INCOMPAT_REVOKE     0x00000001
 190
 191 /* Features known to this kernel version: */
 192 #define JFS_KNOWN_COMPAT_FEATURES       0
 193 #define JFS_KNOWN_ROCOMPAT_FEATURES     0
 194 #define JFS_KNOWN_INCOMPAT_FEATURES     JFS_FEATURE_INCOMPAT_REVOKE
 195
 196 #ifdef __KERNEL__
 197
 198 #include <linux/fs.h>
 199 #include <linux/sched.h>
 200
 201 #define JBD_ASSERTIONS
 202 #ifdef JBD_ASSERTIONS
 203 #define J_ASSERT(assert)                                                \
 204 do {                                                                    \
 205         if (!(assert)) {                                                \
 206                 printk (KERN_EMERG                                      \
 207                         "Assertion failure in %s() at %s:%d: \"%s\"\n", \
 208                         __FUNCTION__, __FILE__, __LINE__, # assert);    \
 209                 BUG();                                                  \
 210         }                                                               \
 211 } while (0)
 212
 213 #if defined(CONFIG_BUFFER_DEBUG)
 214 void buffer_assertion_failure(struct buffer_head *bh);
 215 #define J_ASSERT_BH(bh, expr)                                           \
 216         do {                                                            \
 217                 if (!(expr))                                            \
 218                         buffer_assertion_failure(bh);                   \
 219                 J_ASSERT(expr);                                         \
 220         } while (0)
 221 #define J_ASSERT_JH(jh, expr)   J_ASSERT_BH(jh2bh(jh), expr)
 222 #else
 223 #define J_ASSERT_BH(bh, expr)   J_ASSERT(expr)
 224 #define J_ASSERT_JH(jh, expr)   J_ASSERT(expr)
 225 #endif
 226
 227 #else
 228 #define J_ASSERT(assert)
 229 #endif          /* JBD_ASSERTIONS */
 230
 231 enum jbd_state_bits {
 232         BH_JWrite
 233           = BH_PrivateStart,    /* 1 if being written to log (@@@ DEBUGGING) */
 234         BH_Freed,               /* 1 if buffer has been freed (truncated) */
 235         BH_Revoked,             /* 1 if buffer has been revoked from the log */
 236         BH_RevokeValid,         /* 1 if buffer revoked flag is valid */
 237         BH_JBDDirty,            /* 1 if buffer is dirty but journaled */
 238 };
 239
 240 /* Return true if the buffer is one which JBD is managing */
 241 static inline int buffer_jbd(struct buffer_head *bh)
 242 {
 243         return __buffer_state(bh, JBD);
 244 }
 245
 246 static inline struct buffer_head *jh2bh(struct journal_head *jh)
 247 {
 248         return jh->b_bh;
 249 }
 250
 251 static inline struct journal_head *bh2jh(struct buffer_head *bh)
 252 {
 253         return bh->b_private;
 254 }
 255
 256 struct jbd_revoke_table_s;
 257
 258 /* The handle_t type represents a single atomic update being performed
 259  * by some process.  All filesystem modifications made by the process go
 260  * through this handle.  Recursive operations (such as quota operations)
 261  * are gathered into a single update.
 262  *
 263  * The buffer credits field is used to account for journaled buffers
 264  * being modified by the running process.  To ensure that there is
 265  * enough log space for all outstanding operations, we need to limit the
 266  * number of outstanding buffers possible at any time.  When the
 267  * operation completes, any buffer credits not used are credited back to
 268  * the transaction, so that at all times we know how many buffers the
 269  * outstanding updates on a transaction might possibly touch. */
 270
 271 struct handle_s
 272 {
 273         /* Which compound transaction is this update a part of? */
 274         transaction_t         * h_transaction;
 275
 276         /* Number of remaining buffers we are allowed to dirty: */
 277         int                     h_buffer_credits;
 278
 279         /* Reference count on this handle */
 280         int                     h_ref;
 281
 282         /* Field for caller's use to track errors through large fs
 283            operations */
 284         int                     h_err;
 285
 286         /* Flags */
 287         unsigned int    h_sync:         1;      /* sync-on-close */
 288         unsigned int    h_jdata:        1;      /* force data journaling */
 289         unsigned int    h_aborted:      1;      /* fatal error on handle */
 290 };
 291
 292
 293 /* The transaction_t type is the guts of the journaling mechanism.  It
 294  * tracks a compound transaction through its various states:
 295  *
 296  * RUNNING:     accepting new updates
 297  * LOCKED:      Updates still running but we don't accept new ones
 298  * RUNDOWN:     Updates are tidying up but have finished requesting
 299  *              new buffers to modify (state not used for now)
 300  * FLUSH:       All updates complete, but we are still writing to disk
 301  * COMMIT:      All data on disk, writing commit record
 302  * FINISHED:    We still have to keep the transaction for checkpointing.
 303  *
 304  * The transaction keeps track of all of the buffers modified by a
 305  * running transaction, and all of the buffers committed but not yet
 306  * flushed to home for finished transactions.
 307  */
 308
 309 struct transaction_s
 310 {
 311         /* Pointer to the journal for this transaction. */
 312         journal_t *             t_journal;
 313
 314         /* Sequence number for this transaction */
 315         tid_t                   t_tid;
 316
 317         /* Transaction's current state */
 318         enum {
 319                 T_RUNNING,
 320                 T_LOCKED,
 321                 T_RUNDOWN,
 322                 T_FLUSH,
 323                 T_COMMIT,
 324                 T_FINISHED
 325         }                       t_state;
 326
 327         /* Where in the log does this transaction's commit start? */
 328         unsigned long           t_log_start;
 329
 330         /* Doubly-linked circular list of all inodes owned by this
 331            transaction */       /* AKPM: unused */
 332         struct inode *          t_ilist;
 333
 334         /* Number of buffers on the t_buffers list */
 335         int                     t_nr_buffers;
 336
 337         /* Doubly-linked circular list of all buffers reserved but not
 338            yet modified by this transaction */
 339         struct journal_head *   t_reserved_list;
 340
 341         /* Doubly-linked circular list of all metadata buffers owned by this
 342            transaction */
 343         struct journal_head *   t_buffers;
 344
 345         /*
 346          * Doubly-linked circular list of all data buffers still to be
 347          * flushed before this transaction can be committed.
 348          * Protected by journal_datalist_lock.
 349          */
 350         struct journal_head *   t_sync_datalist;
 351
 352         /*
 353          * Doubly-linked circular list of all writepage data buffers
 354          * still to be written before this transaction can be committed.
 355          * Protected by journal_datalist_lock.
 356          */
 357         struct journal_head *   t_async_datalist;
 358
 359         /* Doubly-linked circular list of all forget buffers (superceded
 360            buffers which we can un-checkpoint once this transaction
 361            commits) */
 362         struct journal_head *   t_forget;
 363
 364         /*
 365          * Doubly-linked circular list of all buffers still to be
 366          * flushed before this transaction can be checkpointed.
 367          */
 368         /* Protected by journal_datalist_lock */
 369         struct journal_head *   t_checkpoint_list;
 370
 371         /* Doubly-linked circular list of temporary buffers currently
 372            undergoing IO in the log */
 373         struct journal_head *   t_iobuf_list;
 374
 375         /* Doubly-linked circular list of metadata buffers being
 376            shadowed by log IO.  The IO buffers on the iobuf list and the
 377            shadow buffers on this list match each other one for one at
 378            all times. */
 379         struct journal_head *   t_shadow_list;
 380
 381         /* Doubly-linked circular list of control buffers being written
 382            to the log. */
 383         struct journal_head *   t_log_list;
 384
 385         /* Number of outstanding updates running on this transaction */
 386         int                     t_updates;
 387
 388         /* Number of buffers reserved for use by all handles in this
 389          * transaction handle but not yet modified. */
 390         int                     t_outstanding_credits;
 391
 392         /*
 393          * Forward and backward links for the circular list of all
 394          * transactions awaiting checkpoint.
 395          */
 396         /* Protected by journal_datalist_lock */
 397         transaction_t           *t_cpnext, *t_cpprev;
 398
 399         /* When will the transaction expire (become due for commit), in
 400          * jiffies ? */
 401         unsigned long           t_expires;
 402
 403         /* How many handles used this transaction? */
 404         int t_handle_count;
 405 };
 406
 407
 408 /* The journal_t maintains all of the journaling state information for a
 409  * single filesystem.  It is linked to from the fs superblock structure.
 410  *
 411  * We use the journal_t to keep track of all outstanding transaction
 412  * activity on the filesystem, and to manage the state of the log
 413  * writing process. */
 414
 415 struct journal_s
 416 {
 417         /* General journaling state flags */
 418         unsigned long           j_flags;
 419
 420         /* Is there an outstanding uncleared error on the journal (from
 421          * a prior abort)? */
 422         int                     j_errno;
 423
 424         /* The superblock buffer */
 425         struct buffer_head *    j_sb_buffer;
 426         journal_superblock_t *  j_superblock;
 427
 428         /* Version of the superblock format */
 429         int                     j_format_version;
 430
 431         /* Number of processes waiting to create a barrier lock */
 432         int                     j_barrier_count;
 433
 434         /* The barrier lock itself */
 435         struct semaphore        j_barrier;
 436
 437         /* Transactions: The current running transaction... */
 438         transaction_t *         j_running_transaction;
 439
 440         /* ... the transaction we are pushing to disk ... */
 441         transaction_t *         j_committing_transaction;
 442
 443         /* ... and a linked circular list of all transactions waiting
 444          * for checkpointing. */
 445         /* Protected by journal_datalist_lock */
 446         transaction_t *         j_checkpoint_transactions;
 447
 448         /* Wait queue for waiting for a locked transaction to start
 449            committing, or for a barrier lock to be released */
 450         wait_queue_head_t       j_wait_transaction_locked;
 451
 452         /* Wait queue for waiting for checkpointing to complete */
 453         wait_queue_head_t       j_wait_logspace;
 454
 455         /* Wait queue for waiting for commit to complete */
 456         wait_queue_head_t       j_wait_done_commit;
 457
 458         /* Wait queue to trigger checkpointing */
 459         wait_queue_head_t       j_wait_checkpoint;
 460
 461         /* Wait queue to trigger commit */
 462         wait_queue_head_t       j_wait_commit;
 463
 464         /* Wait queue to wait for updates to complete */
 465         wait_queue_head_t       j_wait_updates;
 466
 467         /* Semaphore for locking against concurrent checkpoints */
 468         struct semaphore        j_checkpoint_sem;
 469
 470         /* The main journal lock, used by lock_journal() */
 471         struct semaphore        j_sem;
 472
 473         /* Journal head: identifies the first unused block in the journal. */
 474         unsigned long           j_head;
 475
 476         /* Journal tail: identifies the oldest still-used block in the
 477          * journal. */
 478         unsigned long           j_tail;
 479
 480         /* Journal free: how many free blocks are there in the journal? */
 481         unsigned long           j_free;
 482
 483         /* Journal start and end: the block numbers of the first usable
 484          * block and one beyond the last usable block in the journal. */
 485         unsigned long           j_first, j_last;
 486
 487         /* Device, blocksize and starting block offset for the location
 488          * where we store the journal. */
 489         kdev_t                  j_dev;
 490         int                     j_blocksize;
 491         unsigned int            j_blk_offset;
 492
 493         /* Device which holds the client fs.  For internal journal this
 494          * will be equal to j_dev. */
 495         kdev_t                  j_fs_dev;
 496
 497         /* Total maximum capacity of the journal region on disk. */
 498         unsigned int            j_maxlen;
 499
 500         /* Optional inode where we store the journal.  If present, all
 501          * journal block numbers are mapped into this inode via
 502          * bmap(). */
 503         struct inode *          j_inode;
 504
 505         /* Sequence number of the oldest transaction in the log */
 506         tid_t                   j_tail_sequence;
 507         /* Sequence number of the next transaction to grant */
 508         tid_t                   j_transaction_sequence;
 509         /* Sequence number of the most recently committed transaction */
 510         tid_t                   j_commit_sequence;
 511         /* Sequence number of the most recent transaction wanting commit */
 512         tid_t                   j_commit_request;
 513
 514         /* Journal uuid: identifies the object (filesystem, LVM volume
 515          * etc) backed by this journal.  This will eventually be
 516          * replaced by an array of uuids, allowing us to index multiple
 517          * devices within a single journal and to perform atomic updates
 518          * across them.  */
 519
 520         __u8                    j_uuid[16];
 521
 522         /* Pointer to the current commit thread for this journal */
 523         struct task_struct *    j_task;
 524
 525         /* Maximum number of metadata buffers to allow in a single
 526          * compound commit transaction */
 527         int                     j_max_transaction_buffers;
 528
 529         /* What is the maximum transaction lifetime before we begin a
 530          * commit? */
 531         unsigned long           j_commit_interval;
 532
 533         /* The timer used to wakeup the commit thread: */
 534         struct timer_list *     j_commit_timer;
 535         int                     j_commit_timer_active;
 536
 537         /* Link all journals together - system-wide */
 538         struct list_head        j_all_journals;
 539
 540         /* The revoke table: maintains the list of revoked blocks in the
 541            current transaction. */
 542         struct jbd_revoke_table_s *j_revoke;
 543 };
 544
 545 /*
 546  * Journal flag definitions
 547  */
 548 #define JFS_UNMOUNT     0x001   /* Journal thread is being destroyed */
 549 #define JFS_ABORT       0x002   /* Journaling has been aborted for errors. */
 550 #define JFS_ACK_ERR     0x004   /* The errno in the sb has been acked */
 551 #define JFS_FLUSHED     0x008   /* The journal superblock has been flushed */
 552 #define JFS_LOADED      0x010   /* The journal superblock has been loaded */
 553
 554 /*
 555  * Function declarations for the journaling transaction and buffer
 556  * management
 557  */
 558
 559 /* Filing buffers */
 560 extern void __journal_unfile_buffer(struct journal_head *);
 561 extern void journal_unfile_buffer(struct journal_head *);
 562 extern void __journal_refile_buffer(struct journal_head *);
 563 extern void journal_refile_buffer(struct journal_head *);
 564 extern void __journal_file_buffer(struct journal_head *, transaction_t *, int);
 565 extern void __journal_free_buffer(struct journal_head *bh);
 566 extern void journal_file_buffer(struct journal_head *, transaction_t *, int);
 567 extern void __journal_clean_data_list(transaction_t *transaction);
 568
 569 /* Log buffer allocation */
 570 extern struct journal_head * journal_get_descriptor_buffer(journal_t *);
 571 extern unsigned long journal_next_log_block(journal_t *);
 572
 573 /* Commit management */
 574 extern void journal_commit_transaction(journal_t *);
 575
 576 /* Checkpoint list management */
 577 int __journal_clean_checkpoint_list(journal_t *journal);
 578 extern void journal_remove_checkpoint(struct journal_head *);
 579 extern void __journal_remove_checkpoint(struct journal_head *);
 580 extern void journal_insert_checkpoint(struct journal_head *, transaction_t *);
 581 extern void __journal_insert_checkpoint(struct journal_head *,transaction_t *);
 582
 583 /* Buffer IO */
 584 extern int
 585 journal_write_metadata_buffer(transaction_t       *transaction,
 586                               struct journal_head  *jh_in,
 587                               struct journal_head **jh_out,
 588                               int                  blocknr);
 589
 590 /* Transaction locking */
 591 extern void             __wait_on_journal (journal_t *);
 592
 593 /*
 594  * Journal locking.
 595  *
 596  * We need to lock the journal during transaction state changes so that
 597  * nobody ever tries to take a handle on the running transaction while
 598  * we are in the middle of moving it to the commit phase.
 599  *
 600  * Note that the locking is completely interrupt unsafe.  We never touch
 601  * journal structures from interrupts.
 602  *
 603  * In 2.2, the BKL was required for lock_journal.  This is no longer
 604  * the case.
 605  */
 606
 607 static inline void lock_journal(journal_t *journal)
 608 {
 609         down(&journal->j_sem);
 610 }
 611
 612 /* This returns zero if we acquired the semaphore */
 613 static inline int try_lock_journal(journal_t * journal)
 614 {
 615         return down_trylock(&journal->j_sem);
 616 }
 617
 618 static inline void unlock_journal(journal_t * journal)
 619 {
 620         up(&journal->j_sem);
 621 }
 622
 623
 624 static inline handle_t *journal_current_handle(void)
 625 {
 626         return current->journal_info;
 627 }
 628
 629 /* The journaling code user interface:
 630  *
 631  * Create and destroy handles
 632  * Register buffer modifications against the current transaction.
 633  */
 634
 635 extern handle_t *journal_start(journal_t *, int nblocks);
 636 extern handle_t *journal_try_start(journal_t *, int nblocks);
 637 extern int       journal_restart (handle_t *, int nblocks);
 638 extern int       journal_extend (handle_t *, int nblocks);
 639 extern int       journal_get_write_access (handle_t *, struct buffer_head *);
 640 extern int       journal_get_create_access (handle_t *, struct buffer_head *);
 641 extern int       journal_get_undo_access (handle_t *, struct buffer_head *);
 642 extern int       journal_dirty_data (handle_t *,
 643                                 struct buffer_head *, int async);
 644 extern int       journal_dirty_metadata (handle_t *, struct buffer_head *);
 645 extern void      journal_release_buffer (handle_t *, struct buffer_head *);
 646 extern void      journal_forget (handle_t *, struct buffer_head *);
 647 extern void      journal_sync_buffer (struct buffer_head *);
 648 extern int       journal_flushpage(journal_t *, struct page *, unsigned long);
 649 extern int       journal_try_to_free_buffers(journal_t *, struct page *, int);
 650 extern int       journal_stop(handle_t *);
 651 extern int       journal_flush (journal_t *);
 652
 653 extern void      journal_lock_updates (journal_t *);
 654 extern void      journal_unlock_updates (journal_t *);
 655
 656 extern journal_t * journal_init_dev(kdev_t dev, kdev_t fs_dev,
 657                                 int start, int len, int bsize);
 658 extern journal_t * journal_init_inode (struct inode *);
 659 extern int         journal_update_format (journal_t *);
 660 extern int         journal_check_used_features
 661                    (journal_t *, unsigned long, unsigned long, unsigned long);
 662 extern int         journal_check_available_features
 663                    (journal_t *, unsigned long, unsigned long, unsigned long);
 664 extern int         journal_set_features
 665                    (journal_t *, unsigned long, unsigned long, unsigned long);
 666 extern int         journal_create     (journal_t *);
 667 extern int         journal_load       (journal_t *journal);
 668 extern void        journal_destroy    (journal_t *);
 669 extern int         journal_recover    (journal_t *journal);
 670 extern int         journal_wipe       (journal_t *, int);
 671 extern int         journal_skip_recovery (journal_t *);
 672 extern void        journal_update_superblock (journal_t *, int);
 673 extern void        __journal_abort      (journal_t *);
 674 extern void        journal_abort      (journal_t *, int);
 675 extern int         journal_errno      (journal_t *);
 676 extern void        journal_ack_err    (journal_t *);
 677 extern int         journal_clear_err  (journal_t *);
 678 extern unsigned long journal_bmap(journal_t *journal, unsigned long blocknr);
 679 extern int          journal_force_commit(journal_t *journal);
 680
 681 /*
 682  * journal_head management
 683  */
 684 extern struct journal_head
 685                 *journal_add_journal_head(struct buffer_head *bh);
 686 extern void     journal_remove_journal_head(struct buffer_head *bh);
 687 extern void     __journal_remove_journal_head(struct buffer_head *bh);
 688 extern void     journal_unlock_journal_head(struct journal_head *jh);
 689
 690 /* Primary revoke support */
 691 #define JOURNAL_REVOKE_DEFAULT_HASH 256
 692 extern int         journal_init_revoke(journal_t *, int);
 693 extern void        journal_destroy_revoke_caches(void);
 694 extern int         journal_init_revoke_caches(void);
 695
 696 extern void        journal_destroy_revoke(journal_t *);
 697 extern int         journal_revoke (handle_t *,
 698                                 unsigned long, struct buffer_head *);
 699 extern int         journal_cancel_revoke(handle_t *, struct journal_head *);
 700 extern void        journal_write_revoke_records(journal_t *, transaction_t *);
 701
 702 /* Recovery revoke support */
 703 extern int         journal_set_revoke(journal_t *, unsigned long, tid_t);
 704 extern int         journal_test_revoke(journal_t *, unsigned long, tid_t);
 705 extern void        journal_clear_revoke(journal_t *);
 706 extern void        journal_brelse_array(struct buffer_head *b[], int n);
 707
 708 /* The log thread user interface:
 709  *
 710  * Request space in the current transaction, and force transaction commit
 711  * transitions on demand.
 712  */
 713
 714 extern int      log_space_left (journal_t *); /* Called with journal locked */
 715 extern tid_t    log_start_commit (journal_t *, transaction_t *);
 716 extern void     log_wait_commit (journal_t *, tid_t);
 717 extern int      log_do_checkpoint (journal_t *, int);
 718
 719 extern void     log_wait_for_space(journal_t *, int nblocks);
 720 extern void     __journal_drop_transaction(journal_t *, transaction_t *);
 721 extern int      cleanup_journal_tail(journal_t *);
 722
 723 /* Reduce journal memory usage by flushing */
 724 extern void shrink_journal_memory(void);
 725
 726 /* Debugging code only: */
 727
 728 #define jbd_ENOSYS() \
 729 do {                                                                  \
 730         printk (KERN_ERR "JBD unimplemented function " __FUNCTION__); \
 731         current->state = TASK_UNINTERRUPTIBLE;                        \
 732         schedule();                                                   \
 733 } while (1)
 734
 735 /*
 736  * is_journal_abort
 737  *
 738  * Simple test wrapper function to test the JFS_ABORT state flag.  This
 739  * bit, when set, indicates that we have had a fatal error somewhere,
 740  * either inside the journaling layer or indicated to us by the client
 741  * (eg. ext3), and that we and should not commit any further
 742  * transactions.
 743  */
 744
 745 static inline int is_journal_aborted(journal_t *journal)
 746 {
 747         return journal->j_flags & JFS_ABORT;
 748 }
 749
 750 static inline int is_handle_aborted(handle_t *handle)
 751 {
 752         if (handle->h_aborted)
 753                 return 1;
 754         return is_journal_aborted(handle->h_transaction->t_journal);
 755 }
 756
 757 static inline void journal_abort_handle(handle_t *handle)
 758 {
 759         handle->h_aborted = 1;
 760 }
 761
 762 /* Not all architectures define BUG() */
 763 #ifndef BUG
 764  #define BUG() do { \
 765         printk("kernel BUG at %s:%d!\n", __FILE__, __LINE__); \
 766         * ((char *) 0) = 0; \
 767  } while (0)
 768 #endif /* BUG */
 769
 770 #else
 771
 772 extern int         journal_recover    (journal_t *journal);
 773 extern int         journal_skip_recovery (journal_t *);
 774
 775 /* Primary revoke support */
 776 extern int         journal_init_revoke(journal_t *, int);
 777 extern void        journal_destroy_revoke_caches(void);
 778 extern int         journal_init_revoke_caches(void);
 779
 780 /* Recovery revoke support */
 781 extern int         journal_set_revoke(journal_t *, unsigned long, tid_t);
 782 extern int         journal_test_revoke(journal_t *, unsigned long, tid_t);
 783 extern void        journal_clear_revoke(journal_t *);
 784 extern void        journal_brelse_array(struct buffer_head *b[], int n);
 785
 786 extern void        journal_destroy_revoke(journal_t *);
 787 #endif /* __KERNEL__   */
 788
 789 /* Comparison functions for transaction IDs: perform comparisons using
 790  * modulo arithmetic so that they work over sequence number wraps. */
 791
 792 static inline int tid_gt(tid_t x, tid_t y)
 793 {
 794         int difference = (x - y);
 795         return (difference > 0);
 796 }
 797
 798 static inline int tid_geq(tid_t x, tid_t y)
 799 {
 800         int difference = (x - y);
 801         return (difference >= 0);
 802 }
 803
 804 extern int journal_blocks_per_page(struct inode *inode);
 805
 806 /*
 807  * Definitions which augment the buffer_head layer
 808  */
 809
 810 /* journaling buffer types */
 811 #define BJ_None         0       /* Not journaled */
 812 #define BJ_SyncData     1       /* Normal data: flush before commit */
 813 #define BJ_AsyncData    2       /* writepage data: wait on it before commit */
 814 #define BJ_Metadata     3       /* Normal journaled metadata */
 815 #define BJ_Forget       4       /* Buffer superceded by this transaction */
 816 #define BJ_IO           5       /* Buffer is for temporary IO use */
 817 #define BJ_Shadow       6       /* Buffer contents being shadowed to the log */
 818 #define BJ_LogCtl       7       /* Buffer contains log descriptors */
 819 #define BJ_Reserved     8       /* Buffer is reserved for access by journal */
 820 #define BJ_Types        9
 821
 822 extern int jbd_blocks_per_page(struct inode *inode);
 823
 824 #ifdef __KERNEL__
 825
 826 extern spinlock_t jh_splice_lock;
 827 /*
 828  * Once `expr1' has been found true, take jh_splice_lock
 829  * and then reevaluate everything.
 830  */
 831 #define SPLICE_LOCK(expr1, expr2)                               \
 832         ({                                                      \
 833                 int ret = (expr1);                              \
 834                 if (ret) {                                      \
 835                         spin_lock(&jh_splice_lock);             \
 836                         ret = (expr1) && (expr2);               \
 837                         spin_unlock(&jh_splice_lock);           \
 838                 }                                               \
 839                 ret;                                            \
 840         })
 841
 842 /*
 843  * A number of buffer state predicates.  They test for
 844  * buffer_jbd() because they are used in core kernel code.
 845  *
 846  * These will be racy on SMP unless we're *sure* that the
 847  * buffer won't be detached from the journalling system
 848  * in parallel.
 849  */
 850
 851 /* Return true if the buffer is on journal list `list' */
 852 static inline int buffer_jlist_eq(struct buffer_head *bh, int list)
 853 {
 854         return SPLICE_LOCK(buffer_jbd(bh), bh2jh(bh)->b_jlist == list);
 855 }
 856
 857 /* Return true if this bufer is dirty wrt the journal */
 858 static inline int buffer_jdirty(struct buffer_head *bh)
 859 {
 860         return buffer_jbd(bh) && __buffer_state(bh, JBDDirty);
 861 }
 862
 863 /* Return true if it's a data buffer which journalling is managing */
 864 static inline int buffer_jbd_data(struct buffer_head *bh)
 865 {
 866         return SPLICE_LOCK(buffer_jbd(bh),
 867                         bh2jh(bh)->b_jlist == BJ_SyncData ||
 868                         bh2jh(bh)->b_jlist == BJ_AsyncData);
 869 }
 870
 871 #ifdef CONFIG_SMP
 872 #define assert_spin_locked(lock)        J_ASSERT(spin_is_locked(lock))
 873 #else
 874 #define assert_spin_locked(lock)        do {} while(0)
 875 #endif
 876
 877 #define buffer_trace_init(bh)   do {} while (0)
 878 #define print_buffer_fields(bh) do {} while (0)
 879 #define print_buffer_trace(bh)  do {} while (0)
 880 #define BUFFER_TRACE(bh, info)  do {} while (0)
 881 #define BUFFER_TRACE2(bh, bh2, info)    do {} while (0)
 882 #define JBUFFER_TRACE(jh, info) do {} while (0)
 883
 884 #endif  /* __KERNEL__ */
 885
 886 #endif  /* CONFIG_JBD || CONFIG_JBD_MODULE || !__KERNEL__ */
 887
 888 /*
 889  * Compatibility no-ops which allow the kernel to compile without CONFIG_JBD
 890  * go here.
 891  */
 892
 893 #if defined(__KERNEL__) && !(defined(CONFIG_JBD) || defined(CONFIG_JBD_MODULE))
 894
 895 #define J_ASSERT(expr)                  do {} while (0)
 896 #define J_ASSERT_BH(bh, expr)           do {} while (0)
 897 #define buffer_jbd(bh)                  0
 898 #define buffer_jlist_eq(bh, val)        0
 899 #define journal_buffer_journal_lru(bh)  0
 900
 901 #endif  /* defined(__KERNEL__) && !defined(CONFIG_JBD) */
 902 #endif  /* _LINUX_JBD_H */