fs/ocfs2/ocfs2.h

   1 /* -*- mode: c; c-basic-offset: 8; -*-
   2  * vim: noexpandtab sw=8 ts=8 sts=0:
   3  *
   4  * ocfs2.h
   5  *
   6  * Defines macros and structures used in OCFS2
   7  *
   8  * Copyright (C) 2002, 2004 Oracle.  All rights reserved.
   9  *
  10  * This program is free software; you can redistribute it and/or
  11  * modify it under the terms of the GNU General Public
  12  * License as published by the Free Software Foundation; either
  13  * version 2 of the License, or (at your option) any later version.
  14  *
  15  * This program is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  18  * General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU General Public
  21  * License along with this program; if not, write to the
  22  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  23  * Boston, MA 021110-1307, USA.
  24  */
  25
  26 #ifndef OCFS2_H
  27 #define OCFS2_H
  28
  29 #include <linux/spinlock.h>
  30 #include <linux/sched.h>
  31 #include <linux/wait.h>
  32 #include <linux/list.h>
  33 #include <linux/rbtree.h>
  34 #include <linux/workqueue.h>
  35 #include <linux/kref.h>
  36 #include <linux/mutex.h>
  37 #ifndef CONFIG_OCFS2_COMPAT_JBD
  38 # include <linux/jbd2.h>
  39 #else
  40 # include <linux/jbd.h>
  41 # include "ocfs2_jbd_compat.h"
  42 #endif
  43
  44 /* For union ocfs2_dlm_lksb */
  45 #include "stackglue.h"
  46
  47 #include "ocfs2_fs.h"
  48 #include "ocfs2_lockid.h"
  49
  50 /* Most user visible OCFS2 inodes will have very few pieces of
  51  * metadata, but larger files (including bitmaps, etc) must be taken
  52  * into account when designing an access scheme. We allow a small
  53  * amount of inlined blocks to be stored on an array and grow the
  54  * structure into a rb tree when necessary. */
  55 #define OCFS2_INODE_MAX_CACHE_ARRAY 2
  56
  57 struct ocfs2_caching_info {
  58         unsigned int            ci_num_cached;
  59         union {
  60                 sector_t        ci_array[OCFS2_INODE_MAX_CACHE_ARRAY];
  61                 struct rb_root  ci_tree;
  62         } ci_cache;
  63 };
  64
  65 /* this limits us to 256 nodes
  66  * if we need more, we can do a kmalloc for the map */
  67 #define OCFS2_NODE_MAP_MAX_NODES    256
  68 struct ocfs2_node_map {
  69         u16 num_nodes;
  70         unsigned long map[BITS_TO_LONGS(OCFS2_NODE_MAP_MAX_NODES)];
  71 };
  72
  73 enum ocfs2_ast_action {
  74         OCFS2_AST_INVALID = 0,
  75         OCFS2_AST_ATTACH,
  76         OCFS2_AST_CONVERT,
  77         OCFS2_AST_DOWNCONVERT,
  78 };
  79
  80 /* actions for an unlockast function to take. */
  81 enum ocfs2_unlock_action {
  82         OCFS2_UNLOCK_INVALID = 0,
  83         OCFS2_UNLOCK_CANCEL_CONVERT,
  84         OCFS2_UNLOCK_DROP_LOCK,
  85 };
  86
  87 /* ocfs2_lock_res->l_flags flags. */
  88 #define OCFS2_LOCK_ATTACHED      (0x00000001) /* have we initialized
  89                                                * the lvb */
  90 #define OCFS2_LOCK_BUSY          (0x00000002) /* we are currently in
  91                                                * dlm_lock */
  92 #define OCFS2_LOCK_BLOCKED       (0x00000004) /* blocked waiting to
  93                                                * downconvert*/
  94 #define OCFS2_LOCK_LOCAL         (0x00000008) /* newly created inode */
  95 #define OCFS2_LOCK_NEEDS_REFRESH (0x00000010)
  96 #define OCFS2_LOCK_REFRESHING    (0x00000020)
  97 #define OCFS2_LOCK_INITIALIZED   (0x00000040) /* track initialization
  98                                                * for shutdown paths */
  99 #define OCFS2_LOCK_FREEING       (0x00000080) /* help dlmglue track
 100                                                * when to skip queueing
 101                                                * a lock because it's
 102                                                * about to be
 103                                                * dropped. */
 104 #define OCFS2_LOCK_QUEUED        (0x00000100) /* queued for downconvert */
 105 #define OCFS2_LOCK_NOCACHE       (0x00000200) /* don't use a holder count */
 106 #define OCFS2_LOCK_PENDING       (0x00000400) /* This lockres is pending a
 107                                                  call to dlm_lock.  Only
 108                                                  exists with BUSY set. */
 109
 110 struct ocfs2_lock_res_ops;
 111
 112 typedef void (*ocfs2_lock_callback)(int status, unsigned long data);
 113
 114 struct ocfs2_lock_res {
 115         void                    *l_priv;
 116         struct ocfs2_lock_res_ops *l_ops;
 117         spinlock_t               l_lock;
 118
 119         struct list_head         l_blocked_list;
 120         struct list_head         l_mask_waiters;
 121
 122         enum ocfs2_lock_type     l_type;
 123         unsigned long            l_flags;
 124         char                     l_name[OCFS2_LOCK_ID_MAX_LEN];
 125         int                      l_level;
 126         unsigned int             l_ro_holders;
 127         unsigned int             l_ex_holders;
 128         union ocfs2_dlm_lksb     l_lksb;
 129
 130         /* used from AST/BAST funcs. */
 131         enum ocfs2_ast_action    l_action;
 132         enum ocfs2_unlock_action l_unlock_action;
 133         int                      l_requested;
 134         int                      l_blocking;
 135         unsigned int             l_pending_gen;
 136
 137         wait_queue_head_t        l_event;
 138
 139         struct list_head         l_debug_list;
 140
 141 #ifdef CONFIG_OCFS2_FS_STATS
 142         unsigned long long       l_lock_num_prmode;        /* PR acquires */
 143         unsigned long long       l_lock_num_exmode;        /* EX acquires */
 144         unsigned int             l_lock_num_prmode_failed; /* Failed PR gets */
 145         unsigned int             l_lock_num_exmode_failed; /* Failed EX gets */
 146         unsigned long long       l_lock_total_prmode;      /* Tot wait for PR */
 147         unsigned long long       l_lock_total_exmode;      /* Tot wait for EX */
 148         unsigned int             l_lock_max_prmode;        /* Max wait for PR */
 149         unsigned int             l_lock_max_exmode;        /* Max wait for EX */
 150         unsigned int             l_lock_refresh;           /* Disk refreshes */
 151 #endif
 152 };
 153
 154 struct ocfs2_dlm_debug {
 155         struct kref d_refcnt;
 156         struct dentry *d_locking_state;
 157         struct list_head d_lockres_tracking;
 158 };
 159
 160 enum ocfs2_vol_state
 161 {
 162         VOLUME_INIT = 0,
 163         VOLUME_MOUNTED,
 164         VOLUME_DISMOUNTED,
 165         VOLUME_DISABLED
 166 };
 167
 168 struct ocfs2_alloc_stats
 169 {
 170         atomic_t moves;
 171         atomic_t local_data;
 172         atomic_t bitmap_data;
 173         atomic_t bg_allocs;
 174         atomic_t bg_extends;
 175 };
 176
 177 enum ocfs2_local_alloc_state
 178 {
 179         OCFS2_LA_UNUSED = 0,    /* Local alloc will never be used for
 180                                  * this mountpoint. */
 181         OCFS2_LA_ENABLED,       /* Local alloc is in use. */
 182         OCFS2_LA_THROTTLED,     /* Local alloc is in use, but number
 183                                  * of bits has been reduced. */
 184         OCFS2_LA_DISABLED       /* Local alloc has temporarily been
 185                                  * disabled. */
 186 };
 187
 188 enum ocfs2_mount_options
 189 {
 190         OCFS2_MOUNT_HB_LOCAL   = 1 << 0, /* Heartbeat started in local mode */
 191         OCFS2_MOUNT_BARRIER = 1 << 1,   /* Use block barriers */
 192         OCFS2_MOUNT_NOINTR  = 1 << 2,   /* Don't catch signals */
 193         OCFS2_MOUNT_ERRORS_PANIC = 1 << 3, /* Panic on errors */
 194         OCFS2_MOUNT_DATA_WRITEBACK = 1 << 4, /* No data ordering */
 195         OCFS2_MOUNT_LOCALFLOCKS = 1 << 5, /* No cluster aware user file locks */
 196         OCFS2_MOUNT_NOUSERXATTR = 1 << 6, /* No user xattr */
 197         OCFS2_MOUNT_INODE64 = 1 << 7,   /* Allow inode numbers > 2^32 */
 198 };
 199
 200 #define OCFS2_OSB_SOFT_RO       0x0001
 201 #define OCFS2_OSB_HARD_RO       0x0002
 202 #define OCFS2_OSB_ERROR_FS      0x0004
 203 #define OCFS2_DEFAULT_ATIME_QUANTUM     60
 204
 205 struct ocfs2_journal;
 206 struct ocfs2_slot_info;
 207 struct ocfs2_recovery_map;
 208 struct ocfs2_super
 209 {
 210         struct task_struct *commit_task;
 211         struct super_block *sb;
 212         struct inode *root_inode;
 213         struct inode *sys_root_inode;
 214         struct inode *system_inodes[NUM_SYSTEM_INODES];
 215
 216         struct ocfs2_slot_info *slot_info;
 217
 218         u32 *slot_recovery_generations;
 219
 220         spinlock_t node_map_lock;
 221
 222         u64 root_blkno;
 223         u64 system_dir_blkno;
 224         u64 bitmap_blkno;
 225         u32 bitmap_cpg;
 226         u8 *uuid;
 227         char *uuid_str;
 228         u32 uuid_hash;
 229         u8 *vol_label;
 230         u64 first_cluster_group_blkno;
 231         u32 fs_generation;
 232
 233         u32 s_feature_compat;
 234         u32 s_feature_incompat;
 235         u32 s_feature_ro_compat;
 236
 237         /* Protects s_next_generation, osb_flags and s_inode_steal_slot.
 238          * Could protect more on osb as it's very short lived.
 239          */
 240         spinlock_t osb_lock;
 241         u32 s_next_generation;
 242         unsigned long osb_flags;
 243         s16 s_inode_steal_slot;
 244         atomic_t s_num_inodes_stolen;
 245
 246         unsigned long s_mount_opt;
 247         unsigned int s_atime_quantum;
 248
 249         unsigned int max_slots;
 250         unsigned int node_num;
 251         int slot_num;
 252         int preferred_slot;
 253         int s_sectsize_bits;
 254         int s_clustersize;
 255         int s_clustersize_bits;
 256         unsigned int s_xattr_inline_size;
 257
 258         atomic_t vol_state;
 259         struct mutex recovery_lock;
 260         struct ocfs2_recovery_map *recovery_map;
 261         struct task_struct *recovery_thread_task;
 262         int disable_recovery;
 263         wait_queue_head_t checkpoint_event;
 264         atomic_t needs_checkpoint;
 265         struct ocfs2_journal *journal;
 266         unsigned long osb_commit_interval;
 267
 268         struct delayed_work             la_enable_wq;
 269
 270         /*
 271          * Must hold local alloc i_mutex and osb->osb_lock to change
 272          * local_alloc_bits. Reads can be done under either lock.
 273          */
 274         unsigned int local_alloc_bits;
 275         unsigned int local_alloc_default_bits;
 276
 277         enum ocfs2_local_alloc_state local_alloc_state; /* protected
 278                                                          * by osb_lock */
 279
 280         struct buffer_head *local_alloc_bh;
 281
 282         u64 la_last_gd;
 283
 284 #ifdef CONFIG_OCFS2_FS_STATS
 285         struct dentry *local_alloc_debug;
 286         char *local_alloc_debug_buf;
 287 #endif
 288
 289         /* Next two fields are for local node slot recovery during
 290          * mount. */
 291         int dirty;
 292         struct ocfs2_dinode *local_alloc_copy;
 293
 294         struct ocfs2_alloc_stats alloc_stats;
 295         char dev_str[20];               /* "major,minor" of the device */
 296
 297         char osb_cluster_stack[OCFS2_STACK_LABEL_LEN + 1];
 298         struct ocfs2_cluster_connection *cconn;
 299         struct ocfs2_lock_res osb_super_lockres;
 300         struct ocfs2_lock_res osb_rename_lockres;
 301         struct ocfs2_dlm_debug *osb_dlm_debug;
 302
 303         struct dentry *osb_debug_root;
 304
 305         wait_queue_head_t recovery_event;
 306
 307         spinlock_t dc_task_lock;
 308         struct task_struct *dc_task;
 309         wait_queue_head_t dc_event;
 310         unsigned long dc_wake_sequence;
 311         unsigned long dc_work_sequence;
 312
 313         /*
 314          * Any thread can add locks to the list, but the downconvert
 315          * thread is the only one allowed to remove locks. Any change
 316          * to this rule requires updating
 317          * ocfs2_downconvert_thread_do_work().
 318          */
 319         struct list_head blocked_lock_list;
 320         unsigned long blocked_lock_count;
 321
 322         wait_queue_head_t               osb_mount_event;
 323
 324         /* Truncate log info */
 325         struct inode                    *osb_tl_inode;
 326         struct buffer_head              *osb_tl_bh;
 327         struct delayed_work             osb_truncate_log_wq;
 328
 329         struct ocfs2_node_map           osb_recovering_orphan_dirs;
 330         unsigned int                    *osb_orphan_wipes;
 331         wait_queue_head_t               osb_wipe_event;
 332 };
 333
 334 #define OCFS2_SB(sb)        ((struct ocfs2_super *)(sb)->s_fs_info)
 335
 336 static inline int ocfs2_should_order_data(struct inode *inode)
 337 {
 338         if (!S_ISREG(inode->i_mode))
 339                 return 0;
 340         if (OCFS2_SB(inode->i_sb)->s_mount_opt & OCFS2_MOUNT_DATA_WRITEBACK)
 341                 return 0;
 342         return 1;
 343 }
 344
 345 static inline int ocfs2_sparse_alloc(struct ocfs2_super *osb)
 346 {
 347         if (osb->s_feature_incompat & OCFS2_FEATURE_INCOMPAT_SPARSE_ALLOC)
 348                 return 1;
 349         return 0;
 350 }
 351
 352 static inline int ocfs2_writes_unwritten_extents(struct ocfs2_super *osb)
 353 {
 354         /*
 355          * Support for sparse files is a pre-requisite
 356          */
 357         if (!ocfs2_sparse_alloc(osb))
 358                 return 0;
 359
 360         if (osb->s_feature_ro_compat & OCFS2_FEATURE_RO_COMPAT_UNWRITTEN)
 361                 return 1;
 362         return 0;
 363 }
 364
 365 static inline int ocfs2_supports_inline_data(struct ocfs2_super *osb)
 366 {
 367         if (osb->s_feature_incompat & OCFS2_FEATURE_INCOMPAT_INLINE_DATA)
 368                 return 1;
 369         return 0;
 370 }
 371
 372 static inline int ocfs2_supports_xattr(struct ocfs2_super *osb)
 373 {
 374         if (osb->s_feature_incompat & OCFS2_FEATURE_INCOMPAT_XATTR)
 375                 return 1;
 376         return 0;
 377 }
 378
 379 /* set / clear functions because cluster events can make these happen
 380  * in parallel so we want the transitions to be atomic. this also
 381  * means that any future flags osb_flags must be protected by spinlock
 382  * too! */
 383 static inline void ocfs2_set_osb_flag(struct ocfs2_super *osb,
 384                                       unsigned long flag)
 385 {
 386         spin_lock(&osb->osb_lock);
 387         osb->osb_flags |= flag;
 388         spin_unlock(&osb->osb_lock);
 389 }
 390
 391 static inline void ocfs2_set_ro_flag(struct ocfs2_super *osb,
 392                                      int hard)
 393 {
 394         spin_lock(&osb->osb_lock);
 395         osb->osb_flags &= ~(OCFS2_OSB_SOFT_RO|OCFS2_OSB_HARD_RO);
 396         if (hard)
 397                 osb->osb_flags |= OCFS2_OSB_HARD_RO;
 398         else
 399                 osb->osb_flags |= OCFS2_OSB_SOFT_RO;
 400         spin_unlock(&osb->osb_lock);
 401 }
 402
 403 static inline int ocfs2_is_hard_readonly(struct ocfs2_super *osb)
 404 {
 405         int ret;
 406
 407         spin_lock(&osb->osb_lock);
 408         ret = osb->osb_flags & OCFS2_OSB_HARD_RO;
 409         spin_unlock(&osb->osb_lock);
 410
 411         return ret;
 412 }
 413
 414 static inline int ocfs2_is_soft_readonly(struct ocfs2_super *osb)
 415 {
 416         int ret;
 417
 418         spin_lock(&osb->osb_lock);
 419         ret = osb->osb_flags & OCFS2_OSB_SOFT_RO;
 420         spin_unlock(&osb->osb_lock);
 421
 422         return ret;
 423 }
 424
 425 static inline int ocfs2_userspace_stack(struct ocfs2_super *osb)
 426 {
 427         return (osb->s_feature_incompat &
 428                 OCFS2_FEATURE_INCOMPAT_USERSPACE_STACK);
 429 }
 430
 431 static inline int ocfs2_mount_local(struct ocfs2_super *osb)
 432 {
 433         return (osb->s_feature_incompat & OCFS2_FEATURE_INCOMPAT_LOCAL_MOUNT);
 434 }
 435
 436 static inline int ocfs2_uses_extended_slot_map(struct ocfs2_super *osb)
 437 {
 438         return (osb->s_feature_incompat &
 439                 OCFS2_FEATURE_INCOMPAT_EXTENDED_SLOT_MAP);
 440 }
 441
 442
 443 #define OCFS2_IS_VALID_DINODE(ptr)                                      \
 444         (!strcmp((ptr)->i_signature, OCFS2_INODE_SIGNATURE))
 445
 446 #define OCFS2_RO_ON_INVALID_DINODE(__sb, __di)  do {                    \
 447         typeof(__di) ____di = (__di);                                   \
 448         ocfs2_error((__sb),                                             \
 449                 "Dinode # %llu has bad signature %.*s",                 \
 450                 (unsigned long long)le64_to_cpu((____di)->i_blkno), 7,  \
 451                 (____di)->i_signature);                                 \
 452 } while (0)
 453
 454 #define OCFS2_IS_VALID_EXTENT_BLOCK(ptr)                                \
 455         (!strcmp((ptr)->h_signature, OCFS2_EXTENT_BLOCK_SIGNATURE))
 456
 457 #define OCFS2_RO_ON_INVALID_EXTENT_BLOCK(__sb, __eb)    do {            \
 458         typeof(__eb) ____eb = (__eb);                                   \
 459         ocfs2_error((__sb),                                             \
 460                 "Extent Block # %llu has bad signature %.*s",           \
 461                 (unsigned long long)le64_to_cpu((____eb)->h_blkno), 7,  \
 462                 (____eb)->h_signature);                                 \
 463 } while (0)
 464
 465 #define OCFS2_IS_VALID_GROUP_DESC(ptr)                                  \
 466         (!strcmp((ptr)->bg_signature, OCFS2_GROUP_DESC_SIGNATURE))
 467
 468 #define OCFS2_RO_ON_INVALID_GROUP_DESC(__sb, __gd)      do {            \
 469         typeof(__gd) ____gd = (__gd);                                   \
 470                 ocfs2_error((__sb),                                     \
 471                 "Group Descriptor # %llu has bad signature %.*s",       \
 472                 (unsigned long long)le64_to_cpu((____gd)->bg_blkno), 7, \
 473                 (____gd)->bg_signature);                                \
 474 } while (0)
 475
 476 static inline unsigned long ino_from_blkno(struct super_block *sb,
 477                                            u64 blkno)
 478 {
 479         return (unsigned long)(blkno & (u64)ULONG_MAX);
 480 }
 481
 482 static inline u64 ocfs2_clusters_to_blocks(struct super_block *sb,
 483                                            u32 clusters)
 484 {
 485         int c_to_b_bits = OCFS2_SB(sb)->s_clustersize_bits -
 486                 sb->s_blocksize_bits;
 487
 488         return (u64)clusters << c_to_b_bits;
 489 }
 490
 491 static inline u32 ocfs2_blocks_to_clusters(struct super_block *sb,
 492                                            u64 blocks)
 493 {
 494         int b_to_c_bits = OCFS2_SB(sb)->s_clustersize_bits -
 495                 sb->s_blocksize_bits;
 496
 497         return (u32)(blocks >> b_to_c_bits);
 498 }
 499
 500 static inline unsigned int ocfs2_clusters_for_bytes(struct super_block *sb,
 501                                                     u64 bytes)
 502 {
 503         int cl_bits = OCFS2_SB(sb)->s_clustersize_bits;
 504         unsigned int clusters;
 505
 506         bytes += OCFS2_SB(sb)->s_clustersize - 1;
 507         /* OCFS2 just cannot have enough clusters to overflow this */
 508         clusters = (unsigned int)(bytes >> cl_bits);
 509
 510         return clusters;
 511 }
 512
 513 static inline u64 ocfs2_blocks_for_bytes(struct super_block *sb,
 514                                          u64 bytes)
 515 {
 516         bytes += sb->s_blocksize - 1;
 517         return bytes >> sb->s_blocksize_bits;
 518 }
 519
 520 static inline u64 ocfs2_clusters_to_bytes(struct super_block *sb,
 521                                           u32 clusters)
 522 {
 523         return (u64)clusters << OCFS2_SB(sb)->s_clustersize_bits;
 524 }
 525
 526 static inline u64 ocfs2_align_bytes_to_clusters(struct super_block *sb,
 527                                                 u64 bytes)
 528 {
 529         int cl_bits = OCFS2_SB(sb)->s_clustersize_bits;
 530         unsigned int clusters;
 531
 532         clusters = ocfs2_clusters_for_bytes(sb, bytes);
 533         return (u64)clusters << cl_bits;
 534 }
 535
 536 static inline u64 ocfs2_align_bytes_to_blocks(struct super_block *sb,
 537                                               u64 bytes)
 538 {
 539         u64 blocks;
 540
 541         blocks = ocfs2_blocks_for_bytes(sb, bytes);
 542         return blocks << sb->s_blocksize_bits;
 543 }
 544
 545 static inline unsigned long ocfs2_align_bytes_to_sectors(u64 bytes)
 546 {
 547         return (unsigned long)((bytes + 511) >> 9);
 548 }
 549
 550 static inline unsigned int ocfs2_page_index_to_clusters(struct super_block *sb,
 551                                                         unsigned long pg_index)
 552 {
 553         u32 clusters = pg_index;
 554         unsigned int cbits = OCFS2_SB(sb)->s_clustersize_bits;
 555
 556         if (unlikely(PAGE_CACHE_SHIFT > cbits))
 557                 clusters = pg_index << (PAGE_CACHE_SHIFT - cbits);
 558         else if (PAGE_CACHE_SHIFT < cbits)
 559                 clusters = pg_index >> (cbits - PAGE_CACHE_SHIFT);
 560
 561         return clusters;
 562 }
 563
 564 /*
 565  * Find the 1st page index which covers the given clusters.
 566  */
 567 static inline pgoff_t ocfs2_align_clusters_to_page_index(struct super_block *sb,
 568                                                         u32 clusters)
 569 {
 570         unsigned int cbits = OCFS2_SB(sb)->s_clustersize_bits;
 571         pgoff_t index = clusters;
 572
 573         if (PAGE_CACHE_SHIFT > cbits) {
 574                 index = (pgoff_t)clusters >> (PAGE_CACHE_SHIFT - cbits);
 575         } else if (PAGE_CACHE_SHIFT < cbits) {
 576                 index = (pgoff_t)clusters << (cbits - PAGE_CACHE_SHIFT);
 577         }
 578
 579         return index;
 580 }
 581
 582 static inline unsigned int ocfs2_pages_per_cluster(struct super_block *sb)
 583 {
 584         unsigned int cbits = OCFS2_SB(sb)->s_clustersize_bits;
 585         unsigned int pages_per_cluster = 1;
 586
 587         if (PAGE_CACHE_SHIFT < cbits)
 588                 pages_per_cluster = 1 << (cbits - PAGE_CACHE_SHIFT);
 589
 590         return pages_per_cluster;
 591 }
 592
 593 static inline unsigned int ocfs2_megabytes_to_clusters(struct super_block *sb,
 594                                                        unsigned int megs)
 595 {
 596         BUILD_BUG_ON(OCFS2_MAX_CLUSTERSIZE > 1048576);
 597
 598         return megs << (20 - OCFS2_SB(sb)->s_clustersize_bits);
 599 }
 600
 601 static inline void ocfs2_init_inode_steal_slot(struct ocfs2_super *osb)
 602 {
 603         spin_lock(&osb->osb_lock);
 604         osb->s_inode_steal_slot = OCFS2_INVALID_SLOT;
 605         spin_unlock(&osb->osb_lock);
 606         atomic_set(&osb->s_num_inodes_stolen, 0);
 607 }
 608
 609 static inline void ocfs2_set_inode_steal_slot(struct ocfs2_super *osb,
 610                                               s16 slot)
 611 {
 612         spin_lock(&osb->osb_lock);
 613         osb->s_inode_steal_slot = slot;
 614         spin_unlock(&osb->osb_lock);
 615 }
 616
 617 static inline s16 ocfs2_get_inode_steal_slot(struct ocfs2_super *osb)
 618 {
 619         s16 slot;
 620
 621         spin_lock(&osb->osb_lock);
 622         slot = osb->s_inode_steal_slot;
 623         spin_unlock(&osb->osb_lock);
 624
 625         return slot;
 626 }
 627
 628 #define ocfs2_set_bit ext2_set_bit
 629 #define ocfs2_clear_bit ext2_clear_bit
 630 #define ocfs2_test_bit ext2_test_bit
 631 #define ocfs2_find_next_zero_bit ext2_find_next_zero_bit
 632 #endif  /* OCFS2_H */
 633