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 int 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 extern void * __jbd_kmalloc (const char *where, size_t size, gfp_t flags, int retry);
  76 extern void * jbd_slab_alloc(size_t size, gfp_t flags);
  77 extern void jbd_slab_free(void *ptr, size_t size);
  78
  79 #define jbd_kmalloc(size, flags) \
  80         __jbd_kmalloc(__FUNCTION__, (size), (flags), journal_oom_retry)
  81 #define jbd_rep_kmalloc(size, flags) \
  82         __jbd_kmalloc(__FUNCTION__, (size), (flags), 1)
  83
  84 #define JFS_MIN_JOURNAL_BLOCKS 1024
  85
  86 #ifdef __KERNEL__
  87
  88 /**
  89  * typedef handle_t - The handle_t type represents a single atomic update being performed by some process.
  90  *
  91  * All filesystem modifications made by the process go
  92  * through this handle.  Recursive operations (such as quota operations)
  93  * are gathered into a single update.
  94  *
  95  * The buffer credits field is used to account for journaled buffers
  96  * being modified by the running process.  To ensure that there is
  97  * enough log space for all outstanding operations, we need to limit the
  98  * number of outstanding buffers possible at any time.  When the
  99  * operation completes, any buffer credits not used are credited back to
 100  * the transaction, so that at all times we know how many buffers the
 101  * outstanding updates on a transaction might possibly touch.
 102  *
 103  * This is an opaque datatype.
 104  **/
 105 typedef struct handle_s         handle_t;       /* Atomic operation type */
 106
 107
 108 /**
 109  * typedef journal_t - The journal_t maintains all of the journaling state information for a single filesystem.
 110  *
 111  * journal_t is linked to from the fs superblock structure.
 112  *
 113  * We use the journal_t to keep track of all outstanding transaction
 114  * activity on the filesystem, and to manage the state of the log
 115  * writing process.
 116  *
 117  * This is an opaque datatype.
 118  **/
 119 typedef struct journal_s        journal_t;      /* Journal control structure */
 120 #endif
 121
 122 /*
 123  * Internal structures used by the logging mechanism:
 124  */
 125
 126 #define JFS_MAGIC_NUMBER 0xc03b3998U /* The first 4 bytes of /dev/random! */
 127
 128 /*
 129  * On-disk structures
 130  */
 131
 132 /*
 133  * Descriptor block types:
 134  */
 135
 136 #define JFS_DESCRIPTOR_BLOCK    1
 137 #define JFS_COMMIT_BLOCK        2
 138 #define JFS_SUPERBLOCK_V1       3
 139 #define JFS_SUPERBLOCK_V2       4
 140 #define JFS_REVOKE_BLOCK        5
 141
 142 /*
 143  * Standard header for all descriptor blocks:
 144  */
 145 typedef struct journal_header_s
 146 {
 147         __be32          h_magic;
 148         __be32          h_blocktype;
 149         __be32          h_sequence;
 150 } journal_header_t;
 151
 152
 153 /*
 154  * The block tag: used to describe a single buffer in the journal
 155  */
 156 typedef struct journal_block_tag_s
 157 {
 158         __be32          t_blocknr;      /* The on-disk block number */
 159         __be32          t_flags;        /* See below */
 160 } journal_block_tag_t;
 161
 162 /*
 163  * The revoke descriptor: used on disk to describe a series of blocks to
 164  * be revoked from the log
 165  */
 166 typedef struct journal_revoke_header_s
 167 {
 168         journal_header_t r_header;
 169         __be32           r_count;       /* Count of bytes used in the block */
 170 } journal_revoke_header_t;
 171
 172
 173 /* Definitions for the journal tag flags word: */
 174 #define JFS_FLAG_ESCAPE         1       /* on-disk block is escaped */
 175 #define JFS_FLAG_SAME_UUID      2       /* block has same uuid as previous */
 176 #define JFS_FLAG_DELETED        4       /* block deleted by this transaction */
 177 #define JFS_FLAG_LAST_TAG       8       /* last tag in this descriptor block */
 178
 179
 180 /*
 181  * The journal superblock.  All fields are in big-endian byte order.
 182  */
 183 typedef struct journal_superblock_s
 184 {
 185 /* 0x0000 */
 186         journal_header_t s_header;
 187
 188 /* 0x000C */
 189         /* Static information describing the journal */
 190         __be32  s_blocksize;            /* journal device blocksize */
 191         __be32  s_maxlen;               /* total blocks in journal file */
 192         __be32  s_first;                /* first block of log information */
 193
 194 /* 0x0018 */
 195         /* Dynamic information describing the current state of the log */
 196         __be32  s_sequence;             /* first commit ID expected in log */
 197         __be32  s_start;                /* blocknr of start of log */
 198
 199 /* 0x0020 */
 200         /* Error value, as set by journal_abort(). */
 201         __be32  s_errno;
 202
 203 /* 0x0024 */
 204         /* Remaining fields are only valid in a version-2 superblock */
 205         __be32  s_feature_compat;       /* compatible feature set */
 206         __be32  s_feature_incompat;     /* incompatible feature set */
 207         __be32  s_feature_ro_compat;    /* readonly-compatible feature set */
 208 /* 0x0030 */
 209         __u8    s_uuid[16];             /* 128-bit uuid for journal */
 210
 211 /* 0x0040 */
 212         __be32  s_nr_users;             /* Nr of filesystems sharing log */
 213
 214         __be32  s_dynsuper;             /* Blocknr of dynamic superblock copy*/
 215
 216 /* 0x0048 */
 217         __be32  s_max_transaction;      /* Limit of journal blocks per trans.*/
 218         __be32  s_max_trans_data;       /* Limit of data blocks per trans. */
 219
 220 /* 0x0050 */
 221         __u32   s_padding[44];
 222
 223 /* 0x0100 */
 224         __u8    s_users[16*48];         /* ids of all fs'es sharing the log */
 225 /* 0x0400 */
 226 } journal_superblock_t;
 227
 228 #define JFS_HAS_COMPAT_FEATURE(j,mask)                                  \
 229         ((j)->j_format_version >= 2 &&                                  \
 230          ((j)->j_superblock->s_feature_compat & cpu_to_be32((mask))))
 231 #define JFS_HAS_RO_COMPAT_FEATURE(j,mask)                               \
 232         ((j)->j_format_version >= 2 &&                                  \
 233          ((j)->j_superblock->s_feature_ro_compat & cpu_to_be32((mask))))
 234 #define JFS_HAS_INCOMPAT_FEATURE(j,mask)                                \
 235         ((j)->j_format_version >= 2 &&                                  \
 236          ((j)->j_superblock->s_feature_incompat & cpu_to_be32((mask))))
 237
 238 #define JFS_FEATURE_INCOMPAT_REVOKE     0x00000001
 239
 240 /* Features known to this kernel version: */
 241 #define JFS_KNOWN_COMPAT_FEATURES       0
 242 #define JFS_KNOWN_ROCOMPAT_FEATURES     0
 243 #define JFS_KNOWN_INCOMPAT_FEATURES     JFS_FEATURE_INCOMPAT_REVOKE
 244
 245 #ifdef __KERNEL__
 246
 247 #include <linux/fs.h>
 248 #include <linux/sched.h>
 249
 250 #define JBD_ASSERTIONS
 251 #ifdef JBD_ASSERTIONS
 252 #define J_ASSERT(assert)                                                \
 253 do {                                                                    \
 254         if (!(assert)) {                                                \
 255                 printk (KERN_EMERG                                      \
 256                         "Assertion failure in %s() at %s:%d: \"%s\"\n", \
 257                         __FUNCTION__, __FILE__, __LINE__, # assert);    \
 258                 BUG();                                                  \
 259         }                                                               \
 260 } while (0)
 261
 262 #if defined(CONFIG_BUFFER_DEBUG)
 263 void buffer_assertion_failure(struct buffer_head *bh);
 264 #define J_ASSERT_BH(bh, expr)                                           \
 265         do {                                                            \
 266                 if (!(expr))                                            \
 267                         buffer_assertion_failure(bh);                   \
 268                 J_ASSERT(expr);                                         \
 269         } while (0)
 270 #define J_ASSERT_JH(jh, expr)   J_ASSERT_BH(jh2bh(jh), expr)
 271 #else
 272 #define J_ASSERT_BH(bh, expr)   J_ASSERT(expr)
 273 #define J_ASSERT_JH(jh, expr)   J_ASSERT(expr)
 274 #endif
 275
 276 #else
 277 #define J_ASSERT(assert)        do { } while (0)
 278 #endif          /* JBD_ASSERTIONS */
 279
 280 #if defined(JBD_PARANOID_IOFAIL)
 281 #define J_EXPECT(expr, why...)          J_ASSERT(expr)
 282 #define J_EXPECT_BH(bh, expr, why...)   J_ASSERT_BH(bh, expr)
 283 #define J_EXPECT_JH(jh, expr, why...)   J_ASSERT_JH(jh, expr)
 284 #else
 285 #define __journal_expect(expr, why...)                                       \
 286         ({                                                                   \
 287                 int val = (expr);                                            \
 288                 if (!val) {                                                  \
 289                         printk(KERN_ERR                                      \
 290                                 "EXT3-fs unexpected failure: %s;\n",# expr); \
 291                         printk(KERN_ERR why "\n");                           \
 292                 }                                                            \
 293                 val;                                                         \
 294         })
 295 #define J_EXPECT(expr, why...)          __journal_expect(expr, ## why)
 296 #define J_EXPECT_BH(bh, expr, why...)   __journal_expect(expr, ## why)
 297 #define J_EXPECT_JH(jh, expr, why...)   __journal_expect(expr, ## why)
 298 #endif
 299
 300 enum jbd_state_bits {
 301         BH_JBD                  /* Has an attached ext3 journal_head */
 302           = BH_PrivateStart,
 303         BH_JWrite,              /* Being written to log (@@@ DEBUGGING) */
 304         BH_Freed,               /* Has been freed (truncated) */
 305         BH_Revoked,             /* Has been revoked from the log */
 306         BH_RevokeValid,         /* Revoked flag is valid */
 307         BH_JBDDirty,            /* Is dirty but journaled */
 308         BH_State,               /* Pins most journal_head state */
 309         BH_JournalHead,         /* Pins bh->b_private and jh->b_bh */
 310         BH_Unshadow,            /* Dummy bit, for BJ_Shadow wakeup filtering */
 311 };
 312
 313 BUFFER_FNS(JBD, jbd)
 314 BUFFER_FNS(JWrite, jwrite)
 315 BUFFER_FNS(JBDDirty, jbddirty)
 316 TAS_BUFFER_FNS(JBDDirty, jbddirty)
 317 BUFFER_FNS(Revoked, revoked)
 318 TAS_BUFFER_FNS(Revoked, revoked)
 319 BUFFER_FNS(RevokeValid, revokevalid)
 320 TAS_BUFFER_FNS(RevokeValid, revokevalid)
 321 BUFFER_FNS(Freed, freed)
 322
 323 static inline struct buffer_head *jh2bh(struct journal_head *jh)
 324 {
 325         return jh->b_bh;
 326 }
 327
 328 static inline struct journal_head *bh2jh(struct buffer_head *bh)
 329 {
 330         return bh->b_private;
 331 }
 332
 333 static inline void jbd_lock_bh_state(struct buffer_head *bh)
 334 {
 335         bit_spin_lock(BH_State, &bh->b_state);
 336 }
 337
 338 static inline int jbd_trylock_bh_state(struct buffer_head *bh)
 339 {
 340         return bit_spin_trylock(BH_State, &bh->b_state);
 341 }
 342
 343 static inline int jbd_is_locked_bh_state(struct buffer_head *bh)
 344 {
 345         return bit_spin_is_locked(BH_State, &bh->b_state);
 346 }
 347
 348 static inline void jbd_unlock_bh_state(struct buffer_head *bh)
 349 {
 350         bit_spin_unlock(BH_State, &bh->b_state);
 351 }
 352
 353 static inline void jbd_lock_bh_journal_head(struct buffer_head *bh)
 354 {
 355         bit_spin_lock(BH_JournalHead, &bh->b_state);
 356 }
 357
 358 static inline void jbd_unlock_bh_journal_head(struct buffer_head *bh)
 359 {
 360         bit_spin_unlock(BH_JournalHead, &bh->b_state);
 361 }
 362
 363 struct jbd_revoke_table_s;
 364
 365 /**
 366  * struct handle_s - The handle_s type is the concrete type associated with
 367  *     handle_t.
 368  * @h_transaction: Which compound transaction is this update a part of?
 369  * @h_buffer_credits: Number of remaining buffers we are allowed to dirty.
 370  * @h_ref: Reference count on this handle
 371  * @h_err: Field for caller's use to track errors through large fs operations
 372  * @h_sync: flag for sync-on-close
 373  * @h_jdata: flag to force data journaling
 374  * @h_aborted: flag indicating fatal error on handle
 375  **/
 376
 377 /* Docbook can't yet cope with the bit fields, but will leave the documentation
 378  * in so it can be fixed later.
 379  */
 380
 381 struct handle_s
 382 {
 383         /* Which compound transaction is this update a part of? */
 384         transaction_t           *h_transaction;
 385
 386         /* Number of remaining buffers we are allowed to dirty: */
 387         int                     h_buffer_credits;
 388
 389         /* Reference count on this handle */
 390         int                     h_ref;
 391
 392         /* Field for caller's use to track errors through large fs */
 393         /* operations */
 394         int                     h_err;
 395
 396         /* Flags [no locking] */
 397         unsigned int    h_sync:         1;      /* sync-on-close */
 398         unsigned int    h_jdata:        1;      /* force data journaling */
 399         unsigned int    h_aborted:      1;      /* fatal error on handle */
 400
 401 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 402         struct lockdep_map      h_lockdep_map;
 403 #endif
 404 };
 405
 406
 407 /* The transaction_t type is the guts of the journaling mechanism.  It
 408  * tracks a compound transaction through its various states:
 409  *
 410  * RUNNING:     accepting new updates
 411  * LOCKED:      Updates still running but we don't accept new ones
 412  * RUNDOWN:     Updates are tidying up but have finished requesting
 413  *              new buffers to modify (state not used for now)
 414  * FLUSH:       All updates complete, but we are still writing to disk
 415  * COMMIT:      All data on disk, writing commit record
 416  * FINISHED:    We still have to keep the transaction for checkpointing.
 417  *
 418  * The transaction keeps track of all of the buffers modified by a
 419  * running transaction, and all of the buffers committed but not yet
 420  * flushed to home for finished transactions.
 421  */
 422
 423 /*
 424  * Lock ranking:
 425  *
 426  *    j_list_lock
 427  *      ->jbd_lock_bh_journal_head()    (This is "innermost")
 428  *
 429  *    j_state_lock
 430  *    ->jbd_lock_bh_state()
 431  *
 432  *    jbd_lock_bh_state()
 433  *    ->j_list_lock
 434  *
 435  *    j_state_lock
 436  *    ->t_handle_lock
 437  *
 438  *    j_state_lock
 439  *    ->j_list_lock                     (journal_unmap_buffer)
 440  *
 441  */
 442
 443 struct transaction_s
 444 {
 445         /* Pointer to the journal for this transaction. [no locking] */
 446         journal_t               *t_journal;
 447
 448         /* Sequence number for this transaction [no locking] */
 449         tid_t                   t_tid;
 450
 451         /*
 452          * Transaction's current state
 453          * [no locking - only kjournald alters this]
 454          * FIXME: needs barriers
 455          * KLUDGE: [use j_state_lock]
 456          */
 457         enum {
 458                 T_RUNNING,
 459                 T_LOCKED,
 460                 T_RUNDOWN,
 461                 T_FLUSH,
 462                 T_COMMIT,
 463                 T_FINISHED
 464         }                       t_state;
 465
 466         /*
 467          * Where in the log does this transaction's commit start? [no locking]
 468          */
 469         unsigned long           t_log_start;
 470
 471         /* Number of buffers on the t_buffers list [j_list_lock] */
 472         int                     t_nr_buffers;
 473
 474         /*
 475          * Doubly-linked circular list of all buffers reserved but not yet
 476          * modified by this transaction [j_list_lock]
 477          */
 478         struct journal_head     *t_reserved_list;
 479
 480         /*
 481          * Doubly-linked circular list of all buffers under writeout during
 482          * commit [j_list_lock]
 483          */
 484         struct journal_head     *t_locked_list;
 485
 486         /*
 487          * Doubly-linked circular list of all metadata buffers owned by this
 488          * transaction [j_list_lock]
 489          */
 490         struct journal_head     *t_buffers;
 491
 492         /*
 493          * Doubly-linked circular list of all data buffers still to be
 494          * flushed before this transaction can be committed [j_list_lock]
 495          */
 496         struct journal_head     *t_sync_datalist;
 497
 498         /*
 499          * Doubly-linked circular list of all forget buffers (superseded
 500          * buffers which we can un-checkpoint once this transaction commits)
 501          * [j_list_lock]
 502          */
 503         struct journal_head     *t_forget;
 504
 505         /*
 506          * Doubly-linked circular list of all buffers still to be flushed before
 507          * this transaction can be checkpointed. [j_list_lock]
 508          */
 509         struct journal_head     *t_checkpoint_list;
 510
 511         /*
 512          * Doubly-linked circular list of all buffers submitted for IO while
 513          * checkpointing. [j_list_lock]
 514          */
 515         struct journal_head     *t_checkpoint_io_list;
 516
 517         /*
 518          * Doubly-linked circular list of temporary buffers currently undergoing
 519          * IO in the log [j_list_lock]
 520          */
 521         struct journal_head     *t_iobuf_list;
 522
 523         /*
 524          * Doubly-linked circular list of metadata buffers being shadowed by log
 525          * IO.  The IO buffers on the iobuf list and the shadow buffers on this
 526          * list match each other one for one at all times. [j_list_lock]
 527          */
 528         struct journal_head     *t_shadow_list;
 529
 530         /*
 531          * Doubly-linked circular list of control buffers being written to the
 532          * log. [j_list_lock]
 533          */
 534         struct journal_head     *t_log_list;
 535
 536         /*
 537          * Protects info related to handles
 538          */
 539         spinlock_t              t_handle_lock;
 540
 541         /*
 542          * Number of outstanding updates running on this transaction
 543          * [t_handle_lock]
 544          */
 545         int                     t_updates;
 546
 547         /*
 548          * Number of buffers reserved for use by all handles in this transaction
 549          * handle but not yet modified. [t_handle_lock]
 550          */
 551         int                     t_outstanding_credits;
 552
 553         /*
 554          * Forward and backward links for the circular list of all transactions
 555          * awaiting checkpoint. [j_list_lock]
 556          */
 557         transaction_t           *t_cpnext, *t_cpprev;
 558
 559         /*
 560          * When will the transaction expire (become due for commit), in jiffies?
 561          * [no locking]
 562          */
 563         unsigned long           t_expires;
 564
 565         /*
 566          * How many handles used this transaction? [t_handle_lock]
 567          */
 568         int t_handle_count;
 569
 570 };
 571
 572 /**
 573  * struct journal_s - The journal_s type is the concrete type associated with
 574  *     journal_t.
 575  * @j_flags:  General journaling state flags
 576  * @j_errno:  Is there an outstanding uncleared error on the journal (from a
 577  *     prior abort)?
 578  * @j_sb_buffer: First part of superblock buffer
 579  * @j_superblock: Second part of superblock buffer
 580  * @j_format_version: Version of the superblock format
 581  * @j_state_lock: Protect the various scalars in the journal
 582  * @j_barrier_count:  Number of processes waiting to create a barrier lock
 583  * @j_barrier: The barrier lock itself
 584  * @j_running_transaction: The current running transaction..
 585  * @j_committing_transaction: the transaction we are pushing to disk
 586  * @j_checkpoint_transactions: a linked circular list of all transactions
 587  *  waiting for checkpointing
 588  * @j_wait_transaction_locked: Wait queue for waiting for a locked transaction
 589  *  to start committing, or for a barrier lock to be released
 590  * @j_wait_logspace: Wait queue for waiting for checkpointing to complete
 591  * @j_wait_done_commit: Wait queue for waiting for commit to complete
 592  * @j_wait_checkpoint:  Wait queue to trigger checkpointing
 593  * @j_wait_commit: Wait queue to trigger commit
 594  * @j_wait_updates: Wait queue to wait for updates to complete
 595  * @j_checkpoint_mutex: Mutex for locking against concurrent checkpoints
 596  * @j_head: Journal head - identifies the first unused block in the journal
 597  * @j_tail: Journal tail - identifies the oldest still-used block in the
 598  *  journal.
 599  * @j_free: Journal free - how many free blocks are there in the journal?
 600  * @j_first: The block number of the first usable block
 601  * @j_last: The block number one beyond the last usable block
 602  * @j_dev: Device where we store the journal
 603  * @j_blocksize: blocksize for the location where we store the journal.
 604  * @j_blk_offset: starting block offset for into the device where we store the
 605  *     journal
 606  * @j_fs_dev: Device which holds the client fs.  For internal journal this will
 607  *     be equal to j_dev
 608  * @j_maxlen: Total maximum capacity of the journal region on disk.
 609  * @j_list_lock: Protects the buffer lists and internal buffer state.
 610  * @j_inode: Optional inode where we store the journal.  If present, all journal
 611  *     block numbers are mapped into this inode via bmap().
 612  * @j_tail_sequence:  Sequence number of the oldest transaction in the log
 613  * @j_transaction_sequence: Sequence number of the next transaction to grant
 614  * @j_commit_sequence: Sequence number of the most recently committed
 615  *  transaction
 616  * @j_commit_request: Sequence number of the most recent transaction wanting
 617  *     commit
 618  * @j_uuid: Uuid of client object.
 619  * @j_task: Pointer to the current commit thread for this journal
 620  * @j_max_transaction_buffers:  Maximum number of metadata buffers to allow in a
 621  *     single compound commit transaction
 622  * @j_commit_interval: What is the maximum transaction lifetime before we begin
 623  *  a commit?
 624  * @j_commit_timer:  The timer used to wakeup the commit thread
 625  * @j_revoke_lock: Protect the revoke table
 626  * @j_revoke: The revoke table - maintains the list of revoked blocks in the
 627  *     current transaction.
 628  * @j_revoke_table: alternate revoke tables for j_revoke
 629  * @j_wbuf: array of buffer_heads for journal_commit_transaction
 630  * @j_wbufsize: maximum number of buffer_heads allowed in j_wbuf, the
 631  *      number that will fit in j_blocksize
 632  * @j_last_sync_writer: most recent pid which did a synchronous write
 633  * @j_private: An opaque pointer to fs-private information.
 634  */
 635
 636 struct journal_s
 637 {
 638         /* General journaling state flags [j_state_lock] */
 639         unsigned long           j_flags;
 640
 641         /*
 642          * Is there an outstanding uncleared error on the journal (from a prior
 643          * abort)? [j_state_lock]
 644          */
 645         int                     j_errno;
 646
 647         /* The superblock buffer */
 648         struct buffer_head      *j_sb_buffer;
 649         journal_superblock_t    *j_superblock;
 650
 651         /* Version of the superblock format */
 652         int                     j_format_version;
 653
 654         /*
 655          * Protect the various scalars in the journal
 656          */
 657         spinlock_t              j_state_lock;
 658
 659         /*
 660          * Number of processes waiting to create a barrier lock [j_state_lock]
 661          */
 662         int                     j_barrier_count;
 663
 664         /* The barrier lock itself */
 665         struct mutex            j_barrier;
 666
 667         /*
 668          * Transactions: The current running transaction...
 669          * [j_state_lock] [caller holding open handle]
 670          */
 671         transaction_t           *j_running_transaction;
 672
 673         /*
 674          * the transaction we are pushing to disk
 675          * [j_state_lock] [caller holding open handle]
 676          */
 677         transaction_t           *j_committing_transaction;
 678
 679         /*
 680          * ... and a linked circular list of all transactions waiting for
 681          * checkpointing. [j_list_lock]
 682          */
 683         transaction_t           *j_checkpoint_transactions;
 684
 685         /*
 686          * Wait queue for waiting for a locked transaction to start committing,
 687          * or for a barrier lock to be released
 688          */
 689         wait_queue_head_t       j_wait_transaction_locked;
 690
 691         /* Wait queue for waiting for checkpointing to complete */
 692         wait_queue_head_t       j_wait_logspace;
 693
 694         /* Wait queue for waiting for commit to complete */
 695         wait_queue_head_t       j_wait_done_commit;
 696
 697         /* Wait queue to trigger checkpointing */
 698         wait_queue_head_t       j_wait_checkpoint;
 699
 700         /* Wait queue to trigger commit */
 701         wait_queue_head_t       j_wait_commit;
 702
 703         /* Wait queue to wait for updates to complete */
 704         wait_queue_head_t       j_wait_updates;
 705
 706         /* Semaphore for locking against concurrent checkpoints */
 707         struct mutex            j_checkpoint_mutex;
 708
 709         /*
 710          * Journal head: identifies the first unused block in the journal.
 711          * [j_state_lock]
 712          */
 713         unsigned long           j_head;
 714
 715         /*
 716          * Journal tail: identifies the oldest still-used block in the journal.
 717          * [j_state_lock]
 718          */
 719         unsigned long           j_tail;
 720
 721         /*
 722          * Journal free: how many free blocks are there in the journal?
 723          * [j_state_lock]
 724          */
 725         unsigned long           j_free;
 726
 727         /*
 728          * Journal start and end: the block numbers of the first usable block
 729          * and one beyond the last usable block in the journal. [j_state_lock]
 730          */
 731         unsigned long           j_first;
 732         unsigned long           j_last;
 733
 734         /*
 735          * Device, blocksize and starting block offset for the location where we
 736          * store the journal.
 737          */
 738         struct block_device     *j_dev;
 739         int                     j_blocksize;
 740         unsigned long           j_blk_offset;
 741
 742         /*
 743          * Device which holds the client fs.  For internal journal this will be
 744          * equal to j_dev.
 745          */
 746         struct block_device     *j_fs_dev;
 747
 748         /* Total maximum capacity of the journal region on disk. */
 749         unsigned int            j_maxlen;
 750
 751         /*
 752          * Protects the buffer lists and internal buffer state.
 753          */
 754         spinlock_t              j_list_lock;
 755
 756         /* Optional inode where we store the journal.  If present, all */
 757         /* journal block numbers are mapped into this inode via */
 758         /* bmap(). */
 759         struct inode            *j_inode;
 760
 761         /*
 762          * Sequence number of the oldest transaction in the log [j_state_lock]
 763          */
 764         tid_t                   j_tail_sequence;
 765
 766         /*
 767          * Sequence number of the next transaction to grant [j_state_lock]
 768          */
 769         tid_t                   j_transaction_sequence;
 770
 771         /*
 772          * Sequence number of the most recently committed transaction
 773          * [j_state_lock].
 774          */
 775         tid_t                   j_commit_sequence;
 776
 777         /*
 778          * Sequence number of the most recent transaction wanting commit
 779          * [j_state_lock]
 780          */
 781         tid_t                   j_commit_request;
 782
 783         /*
 784          * Journal uuid: identifies the object (filesystem, LVM volume etc)
 785          * backed by this journal.  This will eventually be replaced by an array
 786          * of uuids, allowing us to index multiple devices within a single
 787          * journal and to perform atomic updates across them.
 788          */
 789         __u8                    j_uuid[16];
 790
 791         /* Pointer to the current commit thread for this journal */
 792         struct task_struct      *j_task;
 793
 794         /*
 795          * Maximum number of metadata buffers to allow in a single compound
 796          * commit transaction
 797          */
 798         int                     j_max_transaction_buffers;
 799
 800         /*
 801          * What is the maximum transaction lifetime before we begin a commit?
 802          */
 803         unsigned long           j_commit_interval;
 804
 805         /* The timer used to wakeup the commit thread: */
 806         struct timer_list       j_commit_timer;
 807
 808         /*
 809          * The revoke table: maintains the list of revoked blocks in the
 810          * current transaction.  [j_revoke_lock]
 811          */
 812         spinlock_t              j_revoke_lock;
 813         struct jbd_revoke_table_s *j_revoke;
 814         struct jbd_revoke_table_s *j_revoke_table[2];
 815
 816         /*
 817          * array of bhs for journal_commit_transaction
 818          */
 819         struct buffer_head      **j_wbuf;
 820         int                     j_wbufsize;
 821
 822         pid_t                   j_last_sync_writer;
 823
 824         /*
 825          * An opaque pointer to fs-private information.  ext3 puts its
 826          * superblock pointer here
 827          */
 828         void *j_private;
 829 };
 830
 831 /*
 832  * Journal flag definitions
 833  */
 834 #define JFS_UNMOUNT     0x001   /* Journal thread is being destroyed */
 835 #define JFS_ABORT       0x002   /* Journaling has been aborted for errors. */
 836 #define JFS_ACK_ERR     0x004   /* The errno in the sb has been acked */
 837 #define JFS_FLUSHED     0x008   /* The journal superblock has been flushed */
 838 #define JFS_LOADED      0x010   /* The journal superblock has been loaded */
 839 #define JFS_BARRIER     0x020   /* Use IDE barriers */
 840
 841 /*
 842  * Function declarations for the journaling transaction and buffer
 843  * management
 844  */
 845
 846 /* Filing buffers */
 847 extern void journal_unfile_buffer(journal_t *, struct journal_head *);
 848 extern void __journal_unfile_buffer(struct journal_head *);
 849 extern void __journal_refile_buffer(struct journal_head *);
 850 extern void journal_refile_buffer(journal_t *, struct journal_head *);
 851 extern void __journal_file_buffer(struct journal_head *, transaction_t *, int);
 852 extern void __journal_free_buffer(struct journal_head *bh);
 853 extern void journal_file_buffer(struct journal_head *, transaction_t *, int);
 854 extern void __journal_clean_data_list(transaction_t *transaction);
 855
 856 /* Log buffer allocation */
 857 extern struct journal_head * journal_get_descriptor_buffer(journal_t *);
 858 int journal_next_log_block(journal_t *, unsigned long *);
 859
 860 /* Commit management */
 861 extern void journal_commit_transaction(journal_t *);
 862
 863 /* Checkpoint list management */
 864 int __journal_clean_checkpoint_list(journal_t *journal);
 865 int __journal_remove_checkpoint(struct journal_head *);
 866 void __journal_insert_checkpoint(struct journal_head *, transaction_t *);
 867
 868 /* Buffer IO */
 869 extern int
 870 journal_write_metadata_buffer(transaction_t       *transaction,
 871                               struct journal_head  *jh_in,
 872                               struct journal_head **jh_out,
 873                               unsigned long        blocknr);
 874
 875 /* Transaction locking */
 876 extern void             __wait_on_journal (journal_t *);
 877
 878 /*
 879  * Journal locking.
 880  *
 881  * We need to lock the journal during transaction state changes so that nobody
 882  * ever tries to take a handle on the running transaction while we are in the
 883  * middle of moving it to the commit phase.  j_state_lock does this.
 884  *
 885  * Note that the locking is completely interrupt unsafe.  We never touch
 886  * journal structures from interrupts.
 887  */
 888
 889 static inline handle_t *journal_current_handle(void)
 890 {
 891         return current->journal_info;
 892 }
 893
 894 /* The journaling code user interface:
 895  *
 896  * Create and destroy handles
 897  * Register buffer modifications against the current transaction.
 898  */
 899
 900 extern handle_t *journal_start(journal_t *, int nblocks);
 901 extern int       journal_restart (handle_t *, int nblocks);
 902 extern int       journal_extend (handle_t *, int nblocks);
 903 extern int       journal_get_write_access(handle_t *, struct buffer_head *);
 904 extern int       journal_get_create_access (handle_t *, struct buffer_head *);
 905 extern int       journal_get_undo_access(handle_t *, struct buffer_head *);
 906 extern int       journal_dirty_data (handle_t *, struct buffer_head *);
 907 extern int       journal_dirty_metadata (handle_t *, struct buffer_head *);
 908 extern void      journal_release_buffer (handle_t *, struct buffer_head *);
 909 extern int       journal_forget (handle_t *, struct buffer_head *);
 910 extern void      journal_sync_buffer (struct buffer_head *);
 911 extern void      journal_invalidatepage(journal_t *,
 912                                 struct page *, unsigned long);
 913 extern int       journal_try_to_free_buffers(journal_t *, struct page *, gfp_t);
 914 extern int       journal_stop(handle_t *);
 915 extern int       journal_flush (journal_t *);
 916 extern void      journal_lock_updates (journal_t *);
 917 extern void      journal_unlock_updates (journal_t *);
 918
 919 extern journal_t * journal_init_dev(struct block_device *bdev,
 920                                 struct block_device *fs_dev,
 921                                 int start, int len, int bsize);
 922 extern journal_t * journal_init_inode (struct inode *);
 923 extern int         journal_update_format (journal_t *);
 924 extern int         journal_check_used_features
 925                    (journal_t *, unsigned long, unsigned long, unsigned long);
 926 extern int         journal_check_available_features
 927                    (journal_t *, unsigned long, unsigned long, unsigned long);
 928 extern int         journal_set_features
 929                    (journal_t *, unsigned long, unsigned long, unsigned long);
 930 extern int         journal_create     (journal_t *);
 931 extern int         journal_load       (journal_t *journal);
 932 extern void        journal_destroy    (journal_t *);
 933 extern int         journal_recover    (journal_t *journal);
 934 extern int         journal_wipe       (journal_t *, int);
 935 extern int         journal_skip_recovery        (journal_t *);
 936 extern void        journal_update_superblock    (journal_t *, int);
 937 extern void        __journal_abort_hard (journal_t *);
 938 extern void        journal_abort      (journal_t *, int);
 939 extern int         journal_errno      (journal_t *);
 940 extern void        journal_ack_err    (journal_t *);
 941 extern int         journal_clear_err  (journal_t *);
 942 extern int         journal_bmap(journal_t *, unsigned long, unsigned long *);
 943 extern int         journal_force_commit(journal_t *);
 944
 945 /*
 946  * journal_head management
 947  */
 948 struct journal_head *journal_add_journal_head(struct buffer_head *bh);
 949 struct journal_head *journal_grab_journal_head(struct buffer_head *bh);
 950 void journal_remove_journal_head(struct buffer_head *bh);
 951 void journal_put_journal_head(struct journal_head *jh);
 952
 953 /*
 954  * handle management
 955  */
 956 extern struct kmem_cache *jbd_handle_cache;
 957
 958 static inline handle_t *jbd_alloc_handle(gfp_t gfp_flags)
 959 {
 960         return kmem_cache_alloc(jbd_handle_cache, gfp_flags);
 961 }
 962
 963 static inline void jbd_free_handle(handle_t *handle)
 964 {
 965         kmem_cache_free(jbd_handle_cache, handle);
 966 }
 967
 968 /* Primary revoke support */
 969 #define JOURNAL_REVOKE_DEFAULT_HASH 256
 970 extern int         journal_init_revoke(journal_t *, int);
 971 extern void        journal_destroy_revoke_caches(void);
 972 extern int         journal_init_revoke_caches(void);
 973
 974 extern void        journal_destroy_revoke(journal_t *);
 975 extern int         journal_revoke (handle_t *,
 976                                 unsigned long, struct buffer_head *);
 977 extern int         journal_cancel_revoke(handle_t *, struct journal_head *);
 978 extern void        journal_write_revoke_records(journal_t *, transaction_t *);
 979
 980 /* Recovery revoke support */
 981 extern int      journal_set_revoke(journal_t *, unsigned long, tid_t);
 982 extern int      journal_test_revoke(journal_t *, unsigned long, tid_t);
 983 extern void     journal_clear_revoke(journal_t *);
 984 extern void     journal_switch_revoke_table(journal_t *journal);
 985
 986 /*
 987  * The log thread user interface:
 988  *
 989  * Request space in the current transaction, and force transaction commit
 990  * transitions on demand.
 991  */
 992
 993 int __log_space_left(journal_t *); /* Called with journal locked */
 994 int log_start_commit(journal_t *journal, tid_t tid);
 995 int __log_start_commit(journal_t *journal, tid_t tid);
 996 int journal_start_commit(journal_t *journal, tid_t *tid);
 997 int journal_force_commit_nested(journal_t *journal);
 998 int log_wait_commit(journal_t *journal, tid_t tid);
 999 int log_do_checkpoint(journal_t *journal);
1000
1001 void __log_wait_for_space(journal_t *journal);
1002 extern void     __journal_drop_transaction(journal_t *, transaction_t *);
1003 extern int      cleanup_journal_tail(journal_t *);
1004
1005 /* Debugging code only: */
1006
1007 #define jbd_ENOSYS() \
1008 do {                                                                       \
1009         printk (KERN_ERR "JBD unimplemented function %s\n", __FUNCTION__); \
1010         current->state = TASK_UNINTERRUPTIBLE;                             \
1011         schedule();                                                        \
1012 } while (1)
1013
1014 /*
1015  * is_journal_abort
1016  *
1017  * Simple test wrapper function to test the JFS_ABORT state flag.  This
1018  * bit, when set, indicates that we have had a fatal error somewhere,
1019  * either inside the journaling layer or indicated to us by the client
1020  * (eg. ext3), and that we and should not commit any further
1021  * transactions.
1022  */
1023
1024 static inline int is_journal_aborted(journal_t *journal)
1025 {
1026         return journal->j_flags & JFS_ABORT;
1027 }
1028
1029 static inline int is_handle_aborted(handle_t *handle)
1030 {
1031         if (handle->h_aborted)
1032                 return 1;
1033         return is_journal_aborted(handle->h_transaction->t_journal);
1034 }
1035
1036 static inline void journal_abort_handle(handle_t *handle)
1037 {
1038         handle->h_aborted = 1;
1039 }
1040
1041 #endif /* __KERNEL__   */
1042
1043 /* Comparison functions for transaction IDs: perform comparisons using
1044  * modulo arithmetic so that they work over sequence number wraps. */
1045
1046 static inline int tid_gt(tid_t x, tid_t y)
1047 {
1048         int difference = (x - y);
1049         return (difference > 0);
1050 }
1051
1052 static inline int tid_geq(tid_t x, tid_t y)
1053 {
1054         int difference = (x - y);
1055         return (difference >= 0);
1056 }
1057
1058 extern int journal_blocks_per_page(struct inode *inode);
1059
1060 /*
1061  * Return the minimum number of blocks which must be free in the journal
1062  * before a new transaction may be started.  Must be called under j_state_lock.
1063  */
1064 static inline int jbd_space_needed(journal_t *journal)
1065 {
1066         int nblocks = journal->j_max_transaction_buffers;
1067         if (journal->j_committing_transaction)
1068                 nblocks += journal->j_committing_transaction->
1069                                         t_outstanding_credits;
1070         return nblocks;
1071 }
1072
1073 /*
1074  * Definitions which augment the buffer_head layer
1075  */
1076
1077 /* journaling buffer types */
1078 #define BJ_None         0       /* Not journaled */
1079 #define BJ_SyncData     1       /* Normal data: flush before commit */
1080 #define BJ_Metadata     2       /* Normal journaled metadata */
1081 #define BJ_Forget       3       /* Buffer superseded by this transaction */
1082 #define BJ_IO           4       /* Buffer is for temporary IO use */
1083 #define BJ_Shadow       5       /* Buffer contents being shadowed to the log */
1084 #define BJ_LogCtl       6       /* Buffer contains log descriptors */
1085 #define BJ_Reserved     7       /* Buffer is reserved for access by journal */
1086 #define BJ_Locked       8       /* Locked for I/O during commit */
1087 #define BJ_Types        9
1088
1089 extern int jbd_blocks_per_page(struct inode *inode);
1090
1091 #ifdef __KERNEL__
1092
1093 #define buffer_trace_init(bh)   do {} while (0)
1094 #define print_buffer_fields(bh) do {} while (0)
1095 #define print_buffer_trace(bh)  do {} while (0)
1096 #define BUFFER_TRACE(bh, info)  do {} while (0)
1097 #define BUFFER_TRACE2(bh, bh2, info)    do {} while (0)
1098 #define JBUFFER_TRACE(jh, info) do {} while (0)
1099
1100 #endif  /* __KERNEL__ */
1101
1102 #endif  /* _LINUX_JBD_H */