include/linux/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 /* 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
  35 #include <asm/semaphore.h>
  36 #endif
  37
  38 #define journal_oom_retry 1
  39
  40 /*
  41  * Define JBD_PARANIOD_IOFAIL to cause a kernel BUG() if ext3 finds
  42  * certain classes of error which can occur due to failed IOs.  Under
  43  * normal use we want ext3 to continue after such errors, because
  44  * hardware _can_ fail, but for debugging purposes when running tests on
  45  * known-good hardware we may want to trap these errors.
  46  */
  47 #undef JBD_PARANOID_IOFAIL
  48
  49 /*
  50  * The default maximum commit age, in seconds.
  51  */
  52 #define JBD_DEFAULT_MAX_COMMIT_AGE 5
  53
  54 #ifdef CONFIG_JBD_DEBUG
  55 /*
  56  * Define JBD_EXPENSIVE_CHECKING to enable more expensive internal
  57  * consistency checks.  By default we don't do this unless
  58  * CONFIG_JBD_DEBUG is on.
  59  */
  60 #define JBD_EXPENSIVE_CHECKING
  61 extern u8 journal_enable_debug;
  62
  63 #define jbd_debug(n, f, a...)                                           \
  64         do {                                                            \
  65                 if ((n) <= journal_enable_debug) {                      \
  66                         printk (KERN_DEBUG "(%s, %d): %s: ",            \
  67                                 __FILE__, __LINE__, __FUNCTION__);      \
  68                         printk (f, ## a);                               \
  69                 }                                                       \
  70         } while (0)
  71 #else
  72 #define jbd_debug(f, a...)      /**/
  73 #endif
  74
  75 static inline void *jbd_alloc(size_t size, gfp_t flags)
  76 {
  77         return (void *)__get_free_pages(flags, get_order(size));
  78 }
  79
  80 static inline void jbd_free(void *ptr, size_t size)
  81 {
  82         free_pages((unsigned long)ptr, get_order(size));
  83 };
  84
  85 #define JFS_MIN_JOURNAL_BLOCKS 1024
  86
  87 #ifdef __KERNEL__
  88
  89 /**
  90  * typedef handle_t - The handle_t type represents a single atomic update being performed by some process.
  91  *
  92  * All filesystem modifications made by the process go
  93  * through this handle.  Recursive operations (such as quota operations)
  94  * are gathered into a single update.
  95  *
  96  * The buffer credits field is used to account for journaled buffers
  97  * being modified by the running process.  To ensure that there is
  98  * enough log space for all outstanding operations, we need to limit the
  99  * number of outstanding buffers possible at any time.  When the
 100  * operation completes, any buffer credits not used are credited back to
 101  * the transaction, so that at all times we know how many buffers the
 102  * outstanding updates on a transaction might possibly touch.
 103  *
 104  * This is an opaque datatype.
 105  **/
 106 typedef struct handle_s         handle_t;       /* Atomic operation type */
 107
 108
 109 /**
 110  * typedef journal_t - The journal_t maintains all of the journaling state information for a single filesystem.
 111  *
 112  * journal_t is linked to from the fs superblock structure.
 113  *
 114  * We use the journal_t to keep track of all outstanding transaction
 115  * activity on the filesystem, and to manage the state of the log
 116  * writing process.
 117  *
 118  * This is an opaque datatype.
 119  **/
 120 typedef struct journal_s        journal_t;      /* Journal control structure */
 121 #endif
 122
 123 /*
 124  * Internal structures used by the logging mechanism:
 125  */
 126
 127 #define JFS_MAGIC_NUMBER 0xc03b3998U /* The first 4 bytes of /dev/random! */
 128
 129 /*
 130  * On-disk structures
 131  */
 132
 133 /*
 134  * Descriptor block types:
 135  */
 136
 137 #define JFS_DESCRIPTOR_BLOCK    1
 138 #define JFS_COMMIT_BLOCK        2
 139 #define JFS_SUPERBLOCK_V1       3
 140 #define JFS_SUPERBLOCK_V2       4
 141 #define JFS_REVOKE_BLOCK        5
 142
 143 /*
 144  * Standard header for all descriptor blocks:
 145  */
 146 typedef struct journal_header_s
 147 {
 148         __be32          h_magic;
 149         __be32          h_blocktype;
 150         __be32          h_sequence;
 151 } journal_header_t;
 152
 153
 154 /*
 155  * The block tag: used to describe a single buffer in the journal
 156  */
 157 typedef struct journal_block_tag_s
 158 {
 159         __be32          t_blocknr;      /* The on-disk block number */
 160         __be32          t_flags;        /* See below */
 161 } journal_block_tag_t;
 162
 163 /*
 164  * The revoke descriptor: used on disk to describe a series of blocks to
 165  * be revoked from the log
 166  */
 167 typedef struct journal_revoke_header_s
 168 {
 169         journal_header_t r_header;
 170         __be32           r_count;       /* Count of bytes used in the block */
 171 } journal_revoke_header_t;
 172
 173
 174 /* Definitions for the journal tag flags word: */
 175 #define JFS_FLAG_ESCAPE         1       /* on-disk block is escaped */
 176 #define JFS_FLAG_SAME_UUID      2       /* block has same uuid as previous */
 177 #define JFS_FLAG_DELETED        4       /* block deleted by this transaction */
 178 #define JFS_FLAG_LAST_TAG       8       /* last tag in this descriptor block */
 179
 180
 181 /*
 182  * The journal superblock.  All fields are in big-endian byte order.
 183  */
 184 typedef struct journal_superblock_s
 185 {
 186 /* 0x0000 */
 187         journal_header_t s_header;
 188
 189 /* 0x000C */
 190         /* Static information describing the journal */
 191         __be32  s_blocksize;            /* journal device blocksize */
 192         __be32  s_maxlen;               /* total blocks in journal file */
 193         __be32  s_first;                /* first block of log information */
 194
 195 /* 0x0018 */
 196         /* Dynamic information describing the current state of the log */
 197         __be32  s_sequence;             /* first commit ID expected in log */
 198         __be32  s_start;                /* blocknr of start of log */
 199
 200 /* 0x0020 */
 201         /* Error value, as set by journal_abort(). */
 202         __be32  s_errno;
 203
 204 /* 0x0024 */
 205         /* Remaining fields are only valid in a version-2 superblock */
 206         __be32  s_feature_compat;       /* compatible feature set */
 207         __be32  s_feature_incompat;     /* incompatible feature set */
 208         __be32  s_feature_ro_compat;    /* readonly-compatible feature set */
 209 /* 0x0030 */
 210         __u8    s_uuid[16];             /* 128-bit uuid for journal */
 211
 212 /* 0x0040 */
 213         __be32  s_nr_users;             /* Nr of filesystems sharing log */
 214
 215         __be32  s_dynsuper;             /* Blocknr of dynamic superblock copy*/
 216
 217 /* 0x0048 */
 218         __be32  s_max_transaction;      /* Limit of journal blocks per trans.*/
 219         __be32  s_max_trans_data;       /* Limit of data blocks per trans. */
 220
 221 /* 0x0050 */
 222         __u32   s_padding[44];
 223
 224 /* 0x0100 */
 225         __u8    s_users[16*48];         /* ids of all fs'es sharing the log */
 226 /* 0x0400 */
 227 } journal_superblock_t;
 228
 229 #define JFS_HAS_COMPAT_FEATURE(j,mask)                                  \
 230         ((j)->j_format_version >= 2 &&                                  \
 231          ((j)->j_superblock->s_feature_compat & cpu_to_be32((mask))))
 232 #define JFS_HAS_RO_COMPAT_FEATURE(j,mask)                               \
 233         ((j)->j_format_version >= 2 &&                                  \
 234          ((j)->j_superblock->s_feature_ro_compat & cpu_to_be32((mask))))
 235 #define JFS_HAS_INCOMPAT_FEATURE(j,mask)                                \
 236         ((j)->j_format_version >= 2 &&                                  \
 237          ((j)->j_superblock->s_feature_incompat & cpu_to_be32((mask))))
 238
 239 #define JFS_FEATURE_INCOMPAT_REVOKE     0x00000001
 240
 241 /* Features known to this kernel version: */
 242 #define JFS_KNOWN_COMPAT_FEATURES       0
 243 #define JFS_KNOWN_ROCOMPAT_FEATURES     0
 244 #define JFS_KNOWN_INCOMPAT_FEATURES     JFS_FEATURE_INCOMPAT_REVOKE
 245
 246 #ifdef __KERNEL__
 247
 248 #include <linux/fs.h>
 249 #include <linux/sched.h>
 250
 251 #define J_ASSERT(assert)        BUG_ON(!(assert))
 252
 253 #if defined(CONFIG_BUFFER_DEBUG)
 254 void buffer_assertion_failure(struct buffer_head *bh);
 255 #define J_ASSERT_BH(bh, expr)                                           \
 256         do {                                                            \
 257                 if (!(expr))                                            \
 258                         buffer_assertion_failure(bh);                   \
 259                 J_ASSERT(expr);                                         \
 260         } while (0)
 261 #define J_ASSERT_JH(jh, expr)   J_ASSERT_BH(jh2bh(jh), expr)
 262 #else
 263 #define J_ASSERT_BH(bh, expr)   J_ASSERT(expr)
 264 #define J_ASSERT_JH(jh, expr)   J_ASSERT(expr)
 265 #endif
 266
 267 #if defined(JBD_PARANOID_IOFAIL)
 268 #define J_EXPECT(expr, why...)          J_ASSERT(expr)
 269 #define J_EXPECT_BH(bh, expr, why...)   J_ASSERT_BH(bh, expr)
 270 #define J_EXPECT_JH(jh, expr, why...)   J_ASSERT_JH(jh, expr)
 271 #else
 272 #define __journal_expect(expr, why...)                                       \
 273         ({                                                                   \
 274                 int val = (expr);                                            \
 275                 if (!val) {                                                  \
 276                         printk(KERN_ERR                                      \
 277                                 "EXT3-fs unexpected failure: %s;\n",# expr); \
 278                         printk(KERN_ERR why "\n");                           \
 279                 }                                                            \
 280                 val;                                                         \
 281         })
 282 #define J_EXPECT(expr, why...)          __journal_expect(expr, ## why)
 283 #define J_EXPECT_BH(bh, expr, why...)   __journal_expect(expr, ## why)
 284 #define J_EXPECT_JH(jh, expr, why...)   __journal_expect(expr, ## why)
 285 #endif
 286
 287 enum jbd_state_bits {
 288         BH_JBD                  /* Has an attached ext3 journal_head */
 289           = BH_PrivateStart,
 290         BH_JWrite,              /* Being written to log (@@@ DEBUGGING) */
 291         BH_Freed,               /* Has been freed (truncated) */
 292         BH_Revoked,             /* Has been revoked from the log */
 293         BH_RevokeValid,         /* Revoked flag is valid */
 294         BH_JBDDirty,            /* Is dirty but journaled */
 295         BH_State,               /* Pins most journal_head state */
 296         BH_JournalHead,         /* Pins bh->b_private and jh->b_bh */
 297         BH_Unshadow,            /* Dummy bit, for BJ_Shadow wakeup filtering */
 298 };
 299
 300 BUFFER_FNS(JBD, jbd)
 301 BUFFER_FNS(JWrite, jwrite)
 302 BUFFER_FNS(JBDDirty, jbddirty)
 303 TAS_BUFFER_FNS(JBDDirty, jbddirty)
 304 BUFFER_FNS(Revoked, revoked)
 305 TAS_BUFFER_FNS(Revoked, revoked)
 306 BUFFER_FNS(RevokeValid, revokevalid)
 307 TAS_BUFFER_FNS(RevokeValid, revokevalid)
 308 BUFFER_FNS(Freed, freed)
 309
 310 static inline struct buffer_head *jh2bh(struct journal_head *jh)
 311 {
 312         return jh->b_bh;
 313 }
 314
 315 static inline struct journal_head *bh2jh(struct buffer_head *bh)
 316 {
 317         return bh->b_private;
 318 }
 319
 320 static inline void jbd_lock_bh_state(struct buffer_head *bh)
 321 {
 322         bit_spin_lock(BH_State, &bh->b_state);
 323 }
 324
 325 static inline int jbd_trylock_bh_state(struct buffer_head *bh)
 326 {
 327         return bit_spin_trylock(BH_State, &bh->b_state);
 328 }
 329
 330 static inline int jbd_is_locked_bh_state(struct buffer_head *bh)
 331 {
 332         return bit_spin_is_locked(BH_State, &bh->b_state);
 333 }
 334
 335 static inline void jbd_unlock_bh_state(struct buffer_head *bh)
 336 {
 337         bit_spin_unlock(BH_State, &bh->b_state);
 338 }
 339
 340 static inline void jbd_lock_bh_journal_head(struct buffer_head *bh)
 341 {
 342         bit_spin_lock(BH_JournalHead, &bh->b_state);
 343 }
 344
 345 static inline void jbd_unlock_bh_journal_head(struct buffer_head *bh)
 346 {
 347         bit_spin_unlock(BH_JournalHead, &bh->b_state);
 348 }
 349
 350 struct jbd_revoke_table_s;
 351
 352 /**
 353  * struct handle_s - The handle_s type is the concrete type associated with
 354  *     handle_t.
 355  * @h_transaction: Which compound transaction is this update a part of?
 356  * @h_buffer_credits: Number of remaining buffers we are allowed to dirty.
 357  * @h_ref: Reference count on this handle
 358  * @h_err: Field for caller's use to track errors through large fs operations
 359  * @h_sync: flag for sync-on-close
 360  * @h_jdata: flag to force data journaling
 361  * @h_aborted: flag indicating fatal error on handle
 362  * @h_lockdep_map: lockdep info for debugging lock problems
 363  **/
 364
 365 /* Docbook can't yet cope with the bit fields, but will leave the documentation
 366  * in so it can be fixed later.
 367  */
 368
 369 struct handle_s
 370 {
 371         /* Which compound transaction is this update a part of? */
 372         transaction_t           *h_transaction;
 373
 374         /* Number of remaining buffers we are allowed to dirty: */
 375         int                     h_buffer_credits;
 376
 377         /* Reference count on this handle */
 378         int                     h_ref;
 379
 380         /* Field for caller's use to track errors through large fs */
 381         /* operations */
 382         int                     h_err;
 383
 384         /* Flags [no locking] */
 385         unsigned int    h_sync:         1;      /* sync-on-close */
 386         unsigned int    h_jdata:        1;      /* force data journaling */
 387         unsigned int    h_aborted:      1;      /* fatal error on handle */
 388
 389 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 390         struct lockdep_map      h_lockdep_map;
 391 #endif
 392 };
 393
 394
 395 /* The transaction_t type is the guts of the journaling mechanism.  It
 396  * tracks a compound transaction through its various states:
 397  *
 398  * RUNNING:     accepting new updates
 399  * LOCKED:      Updates still running but we don't accept new ones
 400  * RUNDOWN:     Updates are tidying up but have finished requesting
 401  *              new buffers to modify (state not used for now)
 402  * FLUSH:       All updates complete, but we are still writing to disk
 403  * COMMIT:      All data on disk, writing commit record
 404  * FINISHED:    We still have to keep the transaction for checkpointing.
 405  *
 406  * The transaction keeps track of all of the buffers modified by a
 407  * running transaction, and all of the buffers committed but not yet
 408  * flushed to home for finished transactions.
 409  */
 410
 411 /*
 412  * Lock ranking:
 413  *
 414  *    j_list_lock
 415  *      ->jbd_lock_bh_journal_head()    (This is "innermost")
 416  *
 417  *    j_state_lock
 418  *    ->jbd_lock_bh_state()
 419  *
 420  *    jbd_lock_bh_state()
 421  *    ->j_list_lock
 422  *
 423  *    j_state_lock
 424  *    ->t_handle_lock
 425  *
 426  *    j_state_lock
 427  *    ->j_list_lock                     (journal_unmap_buffer)
 428  *
 429  */
 430
 431 struct transaction_s
 432 {
 433         /* Pointer to the journal for this transaction. [no locking] */
 434         journal_t               *t_journal;
 435
 436         /* Sequence number for this transaction [no locking] */
 437         tid_t                   t_tid;
 438
 439         /*
 440          * Transaction's current state
 441          * [no locking - only kjournald alters this]
 442          * [j_list_lock] guards transition of a transaction into T_FINISHED
 443          * state and subsequent call of __journal_drop_transaction()
 444          * FIXME: needs barriers
 445          * KLUDGE: [use j_state_lock]
 446          */
 447         enum {
 448                 T_RUNNING,
 449                 T_LOCKED,
 450                 T_RUNDOWN,
 451                 T_FLUSH,
 452                 T_COMMIT,
 453                 T_FINISHED
 454         }                       t_state;
 455
 456         /*
 457          * Where in the log does this transaction's commit start? [no locking]
 458          */
 459         unsigned long           t_log_start;
 460
 461         /* Number of buffers on the t_buffers list [j_list_lock] */
 462         int                     t_nr_buffers;
 463
 464         /*
 465          * Doubly-linked circular list of all buffers reserved but not yet
 466          * modified by this transaction [j_list_lock]
 467          */
 468         struct journal_head     *t_reserved_list;
 469
 470         /*
 471          * Doubly-linked circular list of all buffers under writeout during
 472          * commit [j_list_lock]
 473          */
 474         struct journal_head     *t_locked_list;
 475
 476         /*
 477          * Doubly-linked circular list of all metadata buffers owned by this
 478          * transaction [j_list_lock]
 479          */
 480         struct journal_head     *t_buffers;
 481
 482         /*
 483          * Doubly-linked circular list of all data buffers still to be
 484          * flushed before this transaction can be committed [j_list_lock]
 485          */
 486         struct journal_head     *t_sync_datalist;
 487
 488         /*
 489          * Doubly-linked circular list of all forget buffers (superseded
 490          * buffers which we can un-checkpoint once this transaction commits)
 491          * [j_list_lock]
 492          */
 493         struct journal_head     *t_forget;
 494
 495         /*
 496          * Doubly-linked circular list of all buffers still to be flushed before
 497          * this transaction can be checkpointed. [j_list_lock]
 498          */
 499         struct journal_head     *t_checkpoint_list;
 500
 501         /*
 502          * Doubly-linked circular list of all buffers submitted for IO while
 503          * checkpointing. [j_list_lock]
 504          */
 505         struct journal_head     *t_checkpoint_io_list;
 506
 507         /*
 508          * Doubly-linked circular list of temporary buffers currently undergoing
 509          * IO in the log [j_list_lock]
 510          */
 511         struct journal_head     *t_iobuf_list;
 512
 513         /*
 514          * Doubly-linked circular list of metadata buffers being shadowed by log
 515          * IO.  The IO buffers on the iobuf list and the shadow buffers on this
 516          * list match each other one for one at all times. [j_list_lock]
 517          */
 518         struct journal_head     *t_shadow_list;
 519
 520         /*
 521          * Doubly-linked circular list of control buffers being written to the
 522          * log. [j_list_lock]
 523          */
 524         struct journal_head     *t_log_list;
 525
 526         /*
 527          * Protects info related to handles
 528          */
 529         spinlock_t              t_handle_lock;
 530
 531         /*
 532          * Number of outstanding updates running on this transaction
 533          * [t_handle_lock]
 534          */
 535         int                     t_updates;
 536
 537         /*
 538          * Number of buffers reserved for use by all handles in this transaction
 539          * handle but not yet modified. [t_handle_lock]
 540          */
 541         int                     t_outstanding_credits;
 542
 543         /*
 544          * Forward and backward links for the circular list of all transactions
 545          * awaiting checkpoint. [j_list_lock]
 546          */
 547         transaction_t           *t_cpnext, *t_cpprev;
 548
 549         /*
 550          * When will the transaction expire (become due for commit), in jiffies?
 551          * [no locking]
 552          */
 553         unsigned long           t_expires;
 554
 555         /*
 556          * How many handles used this transaction? [t_handle_lock]
 557          */
 558         int t_handle_count;
 559
 560 };
 561
 562 /**
 563  * struct journal_s - The journal_s type is the concrete type associated with
 564  *     journal_t.
 565  * @j_flags:  General journaling state flags
 566  * @j_errno:  Is there an outstanding uncleared error on the journal (from a
 567  *     prior abort)?
 568  * @j_sb_buffer: First part of superblock buffer
 569  * @j_superblock: Second part of superblock buffer
 570  * @j_format_version: Version of the superblock format
 571  * @j_state_lock: Protect the various scalars in the journal
 572  * @j_barrier_count:  Number of processes waiting to create a barrier lock
 573  * @j_barrier: The barrier lock itself
 574  * @j_running_transaction: The current running transaction..
 575  * @j_committing_transaction: the transaction we are pushing to disk
 576  * @j_checkpoint_transactions: a linked circular list of all transactions
 577  *  waiting for checkpointing
 578  * @j_wait_transaction_locked: Wait queue for waiting for a locked transaction
 579  *  to start committing, or for a barrier lock to be released
 580  * @j_wait_logspace: Wait queue for waiting for checkpointing to complete
 581  * @j_wait_done_commit: Wait queue for waiting for commit to complete
 582  * @j_wait_checkpoint:  Wait queue to trigger checkpointing
 583  * @j_wait_commit: Wait queue to trigger commit
 584  * @j_wait_updates: Wait queue to wait for updates to complete
 585  * @j_checkpoint_mutex: Mutex for locking against concurrent checkpoints
 586  * @j_head: Journal head - identifies the first unused block in the journal
 587  * @j_tail: Journal tail - identifies the oldest still-used block in the
 588  *  journal.
 589  * @j_free: Journal free - how many free blocks are there in the journal?
 590  * @j_first: The block number of the first usable block
 591  * @j_last: The block number one beyond the last usable block
 592  * @j_dev: Device where we store the journal
 593  * @j_blocksize: blocksize for the location where we store the journal.
 594  * @j_blk_offset: starting block offset for into the device where we store the
 595  *     journal
 596  * @j_fs_dev: Device which holds the client fs.  For internal journal this will
 597  *     be equal to j_dev
 598  * @j_maxlen: Total maximum capacity of the journal region on disk.
 599  * @j_list_lock: Protects the buffer lists and internal buffer state.
 600  * @j_inode: Optional inode where we store the journal.  If present, all journal
 601  *     block numbers are mapped into this inode via bmap().
 602  * @j_tail_sequence:  Sequence number of the oldest transaction in the log
 603  * @j_transaction_sequence: Sequence number of the next transaction to grant
 604  * @j_commit_sequence: Sequence number of the most recently committed
 605  *  transaction
 606  * @j_commit_request: Sequence number of the most recent transaction wanting
 607  *     commit
 608  * @j_uuid: Uuid of client object.
 609  * @j_task: Pointer to the current commit thread for this journal
 610  * @j_max_transaction_buffers:  Maximum number of metadata buffers to allow in a
 611  *     single compound commit transaction
 612  * @j_commit_interval: What is the maximum transaction lifetime before we begin
 613  *  a commit?
 614  * @j_commit_timer:  The timer used to wakeup the commit thread
 615  * @j_revoke_lock: Protect the revoke table
 616  * @j_revoke: The revoke table - maintains the list of revoked blocks in the
 617  *     current transaction.
 618  * @j_revoke_table: alternate revoke tables for j_revoke
 619  * @j_wbuf: array of buffer_heads for journal_commit_transaction
 620  * @j_wbufsize: maximum number of buffer_heads allowed in j_wbuf, the
 621  *      number that will fit in j_blocksize
 622  * @j_last_sync_writer: most recent pid which did a synchronous write
 623  * @j_private: An opaque pointer to fs-private information.
 624  */
 625
 626 struct journal_s
 627 {
 628         /* General journaling state flags [j_state_lock] */
 629         unsigned long           j_flags;
 630
 631         /*
 632          * Is there an outstanding uncleared error on the journal (from a prior
 633          * abort)? [j_state_lock]
 634          */
 635         int                     j_errno;
 636
 637         /* The superblock buffer */
 638         struct buffer_head      *j_sb_buffer;
 639         journal_superblock_t    *j_superblock;
 640
 641         /* Version of the superblock format */
 642         int                     j_format_version;
 643
 644         /*
 645          * Protect the various scalars in the journal
 646          */
 647         spinlock_t              j_state_lock;
 648
 649         /*
 650          * Number of processes waiting to create a barrier lock [j_state_lock]
 651          */
 652         int                     j_barrier_count;
 653
 654         /* The barrier lock itself */
 655         struct mutex            j_barrier;
 656
 657         /*
 658          * Transactions: The current running transaction...
 659          * [j_state_lock] [caller holding open handle]
 660          */
 661         transaction_t           *j_running_transaction;
 662
 663         /*
 664          * the transaction we are pushing to disk
 665          * [j_state_lock] [caller holding open handle]
 666          */
 667         transaction_t           *j_committing_transaction;
 668
 669         /*
 670          * ... and a linked circular list of all transactions waiting for
 671          * checkpointing. [j_list_lock]
 672          */
 673         transaction_t           *j_checkpoint_transactions;
 674
 675         /*
 676          * Wait queue for waiting for a locked transaction to start committing,
 677          * or for a barrier lock to be released
 678          */
 679         wait_queue_head_t       j_wait_transaction_locked;
 680
 681         /* Wait queue for waiting for checkpointing to complete */
 682         wait_queue_head_t       j_wait_logspace;
 683
 684         /* Wait queue for waiting for commit to complete */
 685         wait_queue_head_t       j_wait_done_commit;
 686
 687         /* Wait queue to trigger checkpointing */
 688         wait_queue_head_t       j_wait_checkpoint;
 689
 690         /* Wait queue to trigger commit */
 691         wait_queue_head_t       j_wait_commit;
 692
 693         /* Wait queue to wait for updates to complete */
 694         wait_queue_head_t       j_wait_updates;
 695
 696         /* Semaphore for locking against concurrent checkpoints */
 697         struct mutex            j_checkpoint_mutex;
 698
 699         /*
 700          * Journal head: identifies the first unused block in the journal.
 701          * [j_state_lock]
 702          */
 703         unsigned long           j_head;
 704
 705         /*
 706          * Journal tail: identifies the oldest still-used block in the journal.
 707          * [j_state_lock]
 708          */
 709         unsigned long           j_tail;
 710
 711         /*
 712          * Journal free: how many free blocks are there in the journal?
 713          * [j_state_lock]
 714          */
 715         unsigned long           j_free;
 716
 717         /*
 718          * Journal start and end: the block numbers of the first usable block
 719          * and one beyond the last usable block in the journal. [j_state_lock]
 720          */
 721         unsigned long           j_first;
 722         unsigned long           j_last;
 723
 724         /*
 725          * Device, blocksize and starting block offset for the location where we
 726          * store the journal.
 727          */
 728         struct block_device     *j_dev;
 729         int                     j_blocksize;
 730         unsigned long           j_blk_offset;
 731
 732         /*
 733          * Device which holds the client fs.  For internal journal this will be
 734          * equal to j_dev.
 735          */
 736         struct block_device     *j_fs_dev;
 737
 738         /* Total maximum capacity of the journal region on disk. */
 739         unsigned int            j_maxlen;
 740
 741         /*
 742          * Protects the buffer lists and internal buffer state.
 743          */
 744         spinlock_t              j_list_lock;
 745
 746         /* Optional inode where we store the journal.  If present, all */
 747         /* journal block numbers are mapped into this inode via */
 748         /* bmap(). */
 749         struct inode            *j_inode;
 750
 751         /*
 752          * Sequence number of the oldest transaction in the log [j_state_lock]
 753          */
 754         tid_t                   j_tail_sequence;
 755
 756         /*
 757          * Sequence number of the next transaction to grant [j_state_lock]
 758          */
 759         tid_t                   j_transaction_sequence;
 760
 761         /*
 762          * Sequence number of the most recently committed transaction
 763          * [j_state_lock].
 764          */
 765         tid_t                   j_commit_sequence;
 766
 767         /*
 768          * Sequence number of the most recent transaction wanting commit
 769          * [j_state_lock]
 770          */
 771         tid_t                   j_commit_request;
 772
 773         /*
 774          * Journal uuid: identifies the object (filesystem, LVM volume etc)
 775          * backed by this journal.  This will eventually be replaced by an array
 776          * of uuids, allowing us to index multiple devices within a single
 777          * journal and to perform atomic updates across them.
 778          */
 779         __u8                    j_uuid[16];
 780
 781         /* Pointer to the current commit thread for this journal */
 782         struct task_struct      *j_task;
 783
 784         /*
 785          * Maximum number of metadata buffers to allow in a single compound
 786          * commit transaction
 787          */
 788         int                     j_max_transaction_buffers;
 789
 790         /*
 791          * What is the maximum transaction lifetime before we begin a commit?
 792          */
 793         unsigned long           j_commit_interval;
 794
 795         /* The timer used to wakeup the commit thread: */
 796         struct timer_list       j_commit_timer;
 797
 798         /*
 799          * The revoke table: maintains the list of revoked blocks in the
 800          * current transaction.  [j_revoke_lock]
 801          */
 802         spinlock_t              j_revoke_lock;
 803         struct jbd_revoke_table_s *j_revoke;
 804         struct jbd_revoke_table_s *j_revoke_table[2];
 805
 806         /*
 807          * array of bhs for journal_commit_transaction
 808          */
 809         struct buffer_head      **j_wbuf;
 810         int                     j_wbufsize;
 811
 812         pid_t                   j_last_sync_writer;
 813
 814         /*
 815          * An opaque pointer to fs-private information.  ext3 puts its
 816          * superblock pointer here
 817          */
 818         void *j_private;
 819 };
 820
 821 /*
 822  * Journal flag definitions
 823  */
 824 #define JFS_UNMOUNT     0x001   /* Journal thread is being destroyed */
 825 #define JFS_ABORT       0x002   /* Journaling has been aborted for errors. */
 826 #define JFS_ACK_ERR     0x004   /* The errno in the sb has been acked */
 827 #define JFS_FLUSHED     0x008   /* The journal superblock has been flushed */
 828 #define JFS_LOADED      0x010   /* The journal superblock has been loaded */
 829 #define JFS_BARRIER     0x020   /* Use IDE barriers */
 830
 831 /*
 832  * Function declarations for the journaling transaction and buffer
 833  * management
 834  */
 835
 836 /* Filing buffers */
 837 extern void journal_unfile_buffer(journal_t *, struct journal_head *);
 838 extern void __journal_unfile_buffer(struct journal_head *);
 839 extern void __journal_refile_buffer(struct journal_head *);
 840 extern void journal_refile_buffer(journal_t *, struct journal_head *);
 841 extern void __journal_file_buffer(struct journal_head *, transaction_t *, int);
 842 extern void __journal_free_buffer(struct journal_head *bh);
 843 extern void journal_file_buffer(struct journal_head *, transaction_t *, int);
 844 extern void __journal_clean_data_list(transaction_t *transaction);
 845
 846 /* Log buffer allocation */
 847 extern struct journal_head * journal_get_descriptor_buffer(journal_t *);
 848 int journal_next_log_block(journal_t *, unsigned long *);
 849
 850 /* Commit management */
 851 extern void journal_commit_transaction(journal_t *);
 852
 853 /* Checkpoint list management */
 854 int __journal_clean_checkpoint_list(journal_t *journal);
 855 int __journal_remove_checkpoint(struct journal_head *);
 856 void __journal_insert_checkpoint(struct journal_head *, transaction_t *);
 857
 858 /* Buffer IO */
 859 extern int
 860 journal_write_metadata_buffer(transaction_t       *transaction,
 861                               struct journal_head  *jh_in,
 862                               struct journal_head **jh_out,
 863                               unsigned long        blocknr);
 864
 865 /* Transaction locking */
 866 extern void             __wait_on_journal (journal_t *);
 867
 868 /*
 869  * Journal locking.
 870  *
 871  * We need to lock the journal during transaction state changes so that nobody
 872  * ever tries to take a handle on the running transaction while we are in the
 873  * middle of moving it to the commit phase.  j_state_lock does this.
 874  *
 875  * Note that the locking is completely interrupt unsafe.  We never touch
 876  * journal structures from interrupts.
 877  */
 878
 879 static inline handle_t *journal_current_handle(void)
 880 {
 881         return current->journal_info;
 882 }
 883
 884 /* The journaling code user interface:
 885  *
 886  * Create and destroy handles
 887  * Register buffer modifications against the current transaction.
 888  */
 889
 890 extern handle_t *journal_start(journal_t *, int nblocks);
 891 extern int       journal_restart (handle_t *, int nblocks);
 892 extern int       journal_extend (handle_t *, int nblocks);
 893 extern int       journal_get_write_access(handle_t *, struct buffer_head *);
 894 extern int       journal_get_create_access (handle_t *, struct buffer_head *);
 895 extern int       journal_get_undo_access(handle_t *, struct buffer_head *);
 896 extern int       journal_dirty_data (handle_t *, struct buffer_head *);
 897 extern int       journal_dirty_metadata (handle_t *, struct buffer_head *);
 898 extern void      journal_release_buffer (handle_t *, struct buffer_head *);
 899 extern int       journal_forget (handle_t *, struct buffer_head *);
 900 extern void      journal_sync_buffer (struct buffer_head *);
 901 extern void      journal_invalidatepage(journal_t *,
 902                                 struct page *, unsigned long);
 903 extern int       journal_try_to_free_buffers(journal_t *, struct page *, gfp_t);
 904 extern int       journal_stop(handle_t *);
 905 extern int       journal_flush (journal_t *);
 906 extern void      journal_lock_updates (journal_t *);
 907 extern void      journal_unlock_updates (journal_t *);
 908
 909 extern journal_t * journal_init_dev(struct block_device *bdev,
 910                                 struct block_device *fs_dev,
 911                                 int start, int len, int bsize);
 912 extern journal_t * journal_init_inode (struct inode *);
 913 extern int         journal_update_format (journal_t *);
 914 extern int         journal_check_used_features
 915                    (journal_t *, unsigned long, unsigned long, unsigned long);
 916 extern int         journal_check_available_features
 917                    (journal_t *, unsigned long, unsigned long, unsigned long);
 918 extern int         journal_set_features
 919                    (journal_t *, unsigned long, unsigned long, unsigned long);
 920 extern int         journal_create     (journal_t *);
 921 extern int         journal_load       (journal_t *journal);
 922 extern void        journal_destroy    (journal_t *);
 923 extern int         journal_recover    (journal_t *journal);
 924 extern int         journal_wipe       (journal_t *, int);
 925 extern int         journal_skip_recovery        (journal_t *);
 926 extern void        journal_update_superblock    (journal_t *, int);
 927 extern void        __journal_abort_hard (journal_t *);
 928 extern void        journal_abort      (journal_t *, int);
 929 extern int         journal_errno      (journal_t *);
 930 extern void        journal_ack_err    (journal_t *);
 931 extern int         journal_clear_err  (journal_t *);
 932 extern int         journal_bmap(journal_t *, unsigned long, unsigned long *);
 933 extern int         journal_force_commit(journal_t *);
 934
 935 /*
 936  * journal_head management
 937  */
 938 struct journal_head *journal_add_journal_head(struct buffer_head *bh);
 939 struct journal_head *journal_grab_journal_head(struct buffer_head *bh);
 940 void journal_remove_journal_head(struct buffer_head *bh);
 941 void journal_put_journal_head(struct journal_head *jh);
 942
 943 /*
 944  * handle management
 945  */
 946 extern struct kmem_cache *jbd_handle_cache;
 947
 948 static inline handle_t *jbd_alloc_handle(gfp_t gfp_flags)
 949 {
 950         return kmem_cache_alloc(jbd_handle_cache, gfp_flags);
 951 }
 952
 953 static inline void jbd_free_handle(handle_t *handle)
 954 {
 955         kmem_cache_free(jbd_handle_cache, handle);
 956 }
 957
 958 /* Primary revoke support */
 959 #define JOURNAL_REVOKE_DEFAULT_HASH 256
 960 extern int         journal_init_revoke(journal_t *, int);
 961 extern void        journal_destroy_revoke_caches(void);
 962 extern int         journal_init_revoke_caches(void);
 963
 964 extern void        journal_destroy_revoke(journal_t *);
 965 extern int         journal_revoke (handle_t *,
 966                                 unsigned long, struct buffer_head *);
 967 extern int         journal_cancel_revoke(handle_t *, struct journal_head *);
 968 extern void        journal_write_revoke_records(journal_t *, transaction_t *);
 969
 970 /* Recovery revoke support */
 971 extern int      journal_set_revoke(journal_t *, unsigned long, tid_t);
 972 extern int      journal_test_revoke(journal_t *, unsigned long, tid_t);
 973 extern void     journal_clear_revoke(journal_t *);
 974 extern void     journal_switch_revoke_table(journal_t *journal);
 975
 976 /*
 977  * The log thread user interface:
 978  *
 979  * Request space in the current transaction, and force transaction commit
 980  * transitions on demand.
 981  */
 982
 983 int __log_space_left(journal_t *); /* Called with journal locked */
 984 int log_start_commit(journal_t *journal, tid_t tid);
 985 int __log_start_commit(journal_t *journal, tid_t tid);
 986 int journal_start_commit(journal_t *journal, tid_t *tid);
 987 int journal_force_commit_nested(journal_t *journal);
 988 int log_wait_commit(journal_t *journal, tid_t tid);
 989 int log_do_checkpoint(journal_t *journal);
 990
 991 void __log_wait_for_space(journal_t *journal);
 992 extern void     __journal_drop_transaction(journal_t *, transaction_t *);
 993 extern int      cleanup_journal_tail(journal_t *);
 994
 995 /* Debugging code only: */
 996
 997 #define jbd_ENOSYS() \
 998 do {                                                                       \
 999         printk (KERN_ERR "JBD unimplemented function %s\n", __FUNCTION__); \
1000         current->state = TASK_UNINTERRUPTIBLE;                             \
1001         schedule();                                                        \
1002 } while (1)
1003
1004 /*
1005  * is_journal_abort
1006  *
1007  * Simple test wrapper function to test the JFS_ABORT state flag.  This
1008  * bit, when set, indicates that we have had a fatal error somewhere,
1009  * either inside the journaling layer or indicated to us by the client
1010  * (eg. ext3), and that we and should not commit any further
1011  * transactions.
1012  */
1013
1014 static inline int is_journal_aborted(journal_t *journal)
1015 {
1016         return journal->j_flags & JFS_ABORT;
1017 }
1018
1019 static inline int is_handle_aborted(handle_t *handle)
1020 {
1021         if (handle->h_aborted)
1022                 return 1;
1023         return is_journal_aborted(handle->h_transaction->t_journal);
1024 }
1025
1026 static inline void journal_abort_handle(handle_t *handle)
1027 {
1028         handle->h_aborted = 1;
1029 }
1030
1031 #endif /* __KERNEL__   */
1032
1033 /* Comparison functions for transaction IDs: perform comparisons using
1034  * modulo arithmetic so that they work over sequence number wraps. */
1035
1036 static inline int tid_gt(tid_t x, tid_t y)
1037 {
1038         int difference = (x - y);
1039         return (difference > 0);
1040 }
1041
1042 static inline int tid_geq(tid_t x, tid_t y)
1043 {
1044         int difference = (x - y);
1045         return (difference >= 0);
1046 }
1047
1048 extern int journal_blocks_per_page(struct inode *inode);
1049
1050 /*
1051  * Return the minimum number of blocks which must be free in the journal
1052  * before a new transaction may be started.  Must be called under j_state_lock.
1053  */
1054 static inline int jbd_space_needed(journal_t *journal)
1055 {
1056         int nblocks = journal->j_max_transaction_buffers;
1057         if (journal->j_committing_transaction)
1058                 nblocks += journal->j_committing_transaction->
1059                                         t_outstanding_credits;
1060         return nblocks;
1061 }
1062
1063 /*
1064  * Definitions which augment the buffer_head layer
1065  */
1066
1067 /* journaling buffer types */
1068 #define BJ_None         0       /* Not journaled */
1069 #define BJ_SyncData     1       /* Normal data: flush before commit */
1070 #define BJ_Metadata     2       /* Normal journaled metadata */
1071 #define BJ_Forget       3       /* Buffer superseded by this transaction */
1072 #define BJ_IO           4       /* Buffer is for temporary IO use */
1073 #define BJ_Shadow       5       /* Buffer contents being shadowed to the log */
1074 #define BJ_LogCtl       6       /* Buffer contains log descriptors */
1075 #define BJ_Reserved     7       /* Buffer is reserved for access by journal */
1076 #define BJ_Locked       8       /* Locked for I/O during commit */
1077 #define BJ_Types        9
1078
1079 extern int jbd_blocks_per_page(struct inode *inode);
1080
1081 #ifdef __KERNEL__
1082
1083 #define buffer_trace_init(bh)   do {} while (0)
1084 #define print_buffer_fields(bh) do {} while (0)
1085 #define print_buffer_trace(bh)  do {} while (0)
1086 #define BUFFER_TRACE(bh, info)  do {} while (0)
1087 #define BUFFER_TRACE2(bh, bh2, info)    do {} while (0)
1088 #define JBUFFER_TRACE(jh, info) do {} while (0)
1089
1090 #endif  /* __KERNEL__ */
1091
1092 #endif  /* _LINUX_JBD_H */