267 lines
8.2 KiB
C
267 lines
8.2 KiB
C
/*-
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* See the file LICENSE for redistribution information.
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*
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* Copyright (c) 1996, 1997
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* Sleepycat Software. All rights reserved.
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*
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* @(#)mp.h 10.14 (Sleepycat) 8/18/97
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*/
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struct __bh; typedef struct __bh BH;
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struct __db_mpreg; typedef struct __db_mpreg DB_MPREG;
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struct __mpool; typedef struct __mpool MPOOL;
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struct __mpoolfile; typedef struct __mpoolfile MPOOLFILE;
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/* Default mpool name. */
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#define DB_DEFAULT_MPOOL_FILE "__db_mpool.share"
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/*
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* We default to 128K (16 8K pages) if the user doesn't specify, and
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* require a minimum of 20K.
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*/
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#define DB_CACHESIZE_DEF (128 * 1024)
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#define DB_CACHESIZE_MIN ( 20 * 1024)
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/* Macro to return per-process address, offsets. */
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#define ADDR(base, offset) ((void *)((u_int8_t *)((base)->addr) + offset))
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#define OFFSET(base, p) ((u_int8_t *)(p) - (u_int8_t *)(base)->addr)
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#define INVALID 0 /* Invalid shared memory offset. */
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#define TEMPORARY "<tmp>" /* Temporary file name. */
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/*
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* There are two kinds of locks in the mpool code. The first is the region
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* lock, used to serialize modifications to all data structures. The second
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* is a per-buffer header lock. The locking order is as follows:
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*
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* Process searching for a buffer:
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* Acquire the region lock.
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* Find the buffer header.
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* Increment the reference count (guarantee the buffer stays).
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* If the BH_LOCKED flag is set:
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* Release the region lock.
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* Acquire the buffer lock.
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* Release the buffer lock.
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* Acquire the region lock.
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* Return the buffer.
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*
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* Process reading/writing a buffer:
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* Acquire the region lock.
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* Find/create the buffer header.
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* If reading, increment the reference count (guarantee the buffer stays).
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* Set the BH_LOCKED flag.
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* Acquire the buffer lock (guaranteed not to block).
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* Release the region lock.
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* Do the I/O and/or initialize buffer contents.
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* Acquire the region lock.
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* Clear the BH_LOCKED flag.
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* Release the region lock.
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* Release the buffer lock.
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* If reading, return the buffer.
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*
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* Pointers to DB_MPOOL, MPOOL, DB_MPOOLFILE and MPOOLFILE structures are not
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* reacquired when a region lock is reacquired because they couldn't have been
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* closed/discarded and because they never move in memory.
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*/
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#define LOCKINIT(dbmp, mutexp) \
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if (F_ISSET(dbmp, MP_LOCKHANDLE | MP_LOCKREGION)) \
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(void)__db_mutex_init(mutexp, (dbmp)->fd)
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#define LOCKHANDLE(dbmp, mutexp) \
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if (F_ISSET(dbmp, MP_LOCKHANDLE)) \
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(void)__db_mutex_lock(mutexp, (dbmp)->fd, \
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(dbmp)->dbenv == NULL ? NULL : (dbmp)->dbenv->db_yield)
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#define UNLOCKHANDLE(dbmp, mutexp) \
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if (F_ISSET(dbmp, MP_LOCKHANDLE)) \
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(void)__db_mutex_unlock(mutexp, (dbmp)->fd)
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#define LOCKREGION(dbmp) \
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if (F_ISSET(dbmp, MP_LOCKREGION)) \
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(void)__db_mutex_lock(&((RLAYOUT *)(dbmp)->mp)->lock, \
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(dbmp)->fd, \
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(dbmp)->dbenv == NULL ? NULL : (dbmp)->dbenv->db_yield)
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#define UNLOCKREGION(dbmp) \
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if (F_ISSET(dbmp, MP_LOCKREGION)) \
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(void)__db_mutex_unlock(&((RLAYOUT *)(dbmp)->mp)->lock, \
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(dbmp)->fd)
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#define LOCKBUFFER(dbmp, bhp) \
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if (F_ISSET(dbmp, MP_LOCKREGION)) \
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(void)__db_mutex_lock(&(bhp)->mutex, (dbmp)->fd, \
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(dbmp)->dbenv == NULL ? NULL : (dbmp)->dbenv->db_yield)
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#define UNLOCKBUFFER(dbmp, bhp) \
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if (F_ISSET(dbmp, MP_LOCKREGION)) \
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(void)__db_mutex_unlock(&(bhp)->mutex, (dbmp)->fd)
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/*
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* DB_MPOOL --
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* Per-process memory pool structure.
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*/
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struct __db_mpool {
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/* These fields need to be protected for multi-threaded support. */
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db_mutex_t mutex; /* Structure lock. */
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/* List of pgin/pgout routines. */
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LIST_HEAD(__db_mpregh, __db_mpreg) dbregq;
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/* List of DB_MPOOLFILE's. */
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TAILQ_HEAD(__db_mpoolfileh, __db_mpoolfile) dbmfq;
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/* These fields are not protected. */
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DB_ENV *dbenv; /* Reference to error information. */
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MPOOL *mp; /* Address of the shared MPOOL. */
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void *maddr; /* Address of mmap'd region. */
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void *addr; /* Address of shalloc() region. */
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DB_HASHTAB *htab; /* Hash table of bucket headers. */
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int fd; /* Underlying mmap'd fd. */
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#define MP_ISPRIVATE 0x01 /* Private, so local memory. */
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#define MP_LOCKHANDLE 0x02 /* Threaded, lock handles and region. */
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#define MP_LOCKREGION 0x04 /* Concurrent access, lock region. */
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u_int32_t flags;
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};
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/*
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* DB_MPREG --
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* DB_MPOOL registry of pgin/pgout functions.
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*/
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struct __db_mpreg {
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LIST_ENTRY(__db_mpreg) q; /* Linked list. */
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int ftype; /* File type. */
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/* Pgin, pgout routines. */
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int (*pgin) __P((db_pgno_t, void *, DBT *));
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int (*pgout) __P((db_pgno_t, void *, DBT *));
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};
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/*
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* DB_MPOOLFILE --
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* Per-process DB_MPOOLFILE information.
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*/
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struct __db_mpoolfile {
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/* These fields need to be protected for multi-threaded support. */
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db_mutex_t mutex; /* Structure lock. */
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int fd; /* Underlying file descriptor. */
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u_int32_t pinref; /* Pinned block reference count. */
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/* These fields are not protected. */
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TAILQ_ENTRY(__db_mpoolfile) q; /* Linked list of DB_MPOOLFILE's. */
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char *path; /* Initial file path. */
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DB_MPOOL *dbmp; /* Overlying DB_MPOOL. */
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MPOOLFILE *mfp; /* Underlying MPOOLFILE. */
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void *addr; /* Address of mmap'd region. */
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size_t len; /* Length of mmap'd region. */
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#define MP_PATH_ALLOC 0x01 /* Path is allocated memory. */
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#define MP_PATH_TEMP 0x02 /* Backing file is a temporary. */
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#define MP_READONLY 0x04 /* File is readonly. */
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u_int32_t flags;
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};
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/*
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* MPOOL --
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* Shared memory pool region. One of these is allocated in shared
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* memory, and describes the pool.
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*/
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struct __mpool {
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RLAYOUT rlayout; /* General region information. */
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SH_TAILQ_HEAD(__bhq) bhq; /* LRU list of buckets. */
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SH_TAILQ_HEAD(__bhfq) bhfq; /* Free buckets. */
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SH_TAILQ_HEAD(__mpfq) mpfq; /* List of MPOOLFILEs. */
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/*
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* We make the assumption that the early pages of the file are far
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* more likely to be retrieved than the later pages, which means
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* that the top bits are more interesting for hashing since they're
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* less likely to collide. On the other hand, since 512 4K pages
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* represents a 2MB file, only the bottom 9 bits of the page number
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* are likely to be set. We XOR in the offset in the MPOOL of the
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* MPOOLFILE that backs this particular page, since that should also
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* be unique for the page.
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*/
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#define BUCKET(mp, mf_offset, pgno) \
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(((pgno) ^ ((mf_offset) << 9)) % (mp)->htab_buckets)
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size_t htab; /* Hash table offset. */
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size_t htab_buckets; /* Number of hash table entries. */
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DB_LSN lsn; /* Maximum checkpoint LSN. */
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int lsn_cnt; /* Checkpoint buffers left to write. */
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DB_MPOOL_STAT stat; /* Global mpool statistics. */
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#define MP_LSN_RETRY 0x01 /* Retry all BH_WRITE buffers. */
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u_int32_t flags;
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};
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/*
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* MPOOLFILE --
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* Shared DB_MPOOLFILE information.
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*/
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struct __mpoolfile {
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SH_TAILQ_ENTRY q; /* List of MPOOLFILEs */
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u_int32_t ref; /* Reference count. */
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int ftype; /* File type. */
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int can_mmap; /* If the file can be mmap'd. */
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int lsn_off; /* Page's LSN offset. */
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size_t path_off; /* File name location. */
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size_t fileid_off; /* File identification location. */
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size_t pgcookie_len; /* Pgin/pgout cookie length. */
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size_t pgcookie_off; /* Pgin/pgout cookie location. */
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int lsn_cnt; /* Checkpoint buffers left to write. */
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DB_MPOOL_FSTAT stat; /* Per-file mpool statistics. */
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};
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/*
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* BH --
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* Buffer header.
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*/
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struct __bh {
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db_mutex_t mutex; /* Structure lock. */
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u_int16_t ref; /* Reference count. */
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#define BH_CALLPGIN 0x001 /* Page needs to be reworked... */
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#define BH_DIRTY 0x002 /* Page was modified. */
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#define BH_DISCARD 0x004 /* Page is useless. */
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#define BH_LOCKED 0x008 /* Page is locked (I/O in progress). */
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#define BH_TRASH 0x010 /* Page is garbage. */
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#define BH_WRITE 0x020 /* Page scheduled for writing. */
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u_int16_t flags;
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SH_TAILQ_ENTRY q; /* LRU list of bucket headers. */
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SH_TAILQ_ENTRY mq; /* MPOOLFILE list of bucket headers. */
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db_pgno_t pgno; /* Underlying MPOOLFILE page number. */
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size_t mf_offset; /* Associated MPOOLFILE offset. */
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/*
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* !!!
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* This array must be size_t aligned -- the DB access methods put PAGE
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* and other structures into it, and expect to be able to access them
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* directly. (We guarantee size_t alignment in the db_mpool(3) manual
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* page as well.)
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*/
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u_int8_t buf[1]; /* Variable length data. */
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};
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#include "mp_ext.h"
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