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