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Merge remote branch 'origin/mdb.master'

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This commit is contained in:
Howard Chu 2013-04-30 23:18:01 -07:00
commit 054812517f
2 changed files with 194 additions and 121 deletions
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58
libraries/liblmdb/lmdb.h
View file

@ -66,6 +66,7 @@
*
* - A thread can only use one transaction at a time, plus any child
* transactions. Each transaction belongs to one thread. See below.
* The #MDB_NOTLS flag changes this for read-only transactions.
*
* - Use an MDB_env* in the process which opened it, without fork()ing.
*
@ -249,6 +250,8 @@ typedef void (MDB_rel_func)(MDB_val *item, void *oldptr, void *newptr, void *rel
#define MDB_WRITEMAP 0x80000
/** use asynchronous msync when MDB_WRITEMAP is used */
#define MDB_MAPASYNC 0x100000
/** tie reader locktable slots to #MDB_txn objects instead of to threads */
#define MDB_NOTLS 0x200000
/** @} */
/** @defgroup mdb_dbi_open Database Flags
@ -370,7 +373,9 @@ typedef enum MDB_cursor_op {
#define MDB_MAP_RESIZED (-30785)
/** Database flags changed or would change */
#define MDB_INCOMPATIBLE (-30784)
#define MDB_LAST_ERRCODE MDB_INCOMPATIBLE
/** Invalid reuse of reader locktable slot */
#define MDB_BAD_RSLOT (-30783)
#define MDB_LAST_ERRCODE MDB_BAD_RSLOT
/** @} */
/** @brief Statistics for a database in the environment */
@ -390,8 +395,8 @@ typedef struct MDB_envinfo {
size_t me_mapsize; /**< Size of the data memory map */
size_t me_last_pgno; /**< ID of the last used page */
size_t me_last_txnid; /**< ID of the last committed transaction */
unsigned int me_maxreaders; /**< maximum number of threads for the environment */
unsigned int me_numreaders; /**< maximum number of threads used in the environment */
unsigned int me_maxreaders; /**< max reader slots in the environment */
unsigned int me_numreaders; /**< max reader slots used in the environment */
} MDB_envinfo;
/** @brief Return the mdb library version information.
@ -490,6 +495,15 @@ int mdb_env_create(MDB_env **env);
* database or lose the last transactions. Calling #mdb_env_sync()
* ensures on-disk database integrity until next commit.
* This flag may be changed at any time using #mdb_env_set_flags().
* <li>#MDB_NOTLS
* Don't use Thread-Local Storage. Tie reader locktable slots to
* #MDB_txn objects instead of to threads. I.e. #mdb_txn_reset() keeps
* the slot reseved for the #MDB_txn object. A thread may use parallel
* read-only transactions. A read-only transaction may span threads if
* the user synchronizes its use. Applications that multiplex many
* user threads over individual OS threads need this option. Such an
* application must also serialize the write transactions in an OS
* thread, since MDB's write locking is unaware of the user threads.
* </ul>
* @param[in] mode The UNIX permissions to set on created files. This parameter
* is ignored on Windows.
@ -624,13 +638,17 @@ int mdb_env_get_path(MDB_env *env, const char **path);
*/
int mdb_env_set_mapsize(MDB_env *env, size_t size);
/** @brief Set the maximum number of threads for the environment.
/** @brief Set the maximum number of threads/reader slots for the environment.
*
* This defines the number of slots in the lock table that is used to track readers in the
* the environment. The default is 126.
* Starting a read-only transaction normally ties a lock table slot to the
* current thread until the environment closes or the thread exits. If
* MDB_NOTLS is in use, #mdb_txn_begin() instead ties the slot to the
* MDB_txn object until it or the #MDB_env object is destroyed.
* This function may only be called after #mdb_env_create() and before #mdb_env_open().
* @param[in] env An environment handle returned by #mdb_env_create()
* @param[in] readers The maximum number of threads
* @param[in] readers The maximum number of reader lock table slots
* @return A non-zero error value on failure and 0 on success. Some possible
* errors are:
* <ul>
@ -639,7 +657,7 @@ int mdb_env_set_mapsize(MDB_env *env, size_t size);
*/
int mdb_env_set_maxreaders(MDB_env *env, unsigned int readers);
/** @brief Get the maximum number of threads for the environment.
/** @brief Get the maximum number of threads/reader slots for the environment.
*
* @param[in] env An environment handle returned by #mdb_env_create()
* @param[out] readers Address of an integer to store the number of readers
@ -670,8 +688,9 @@ int mdb_env_set_maxdbs(MDB_env *env, MDB_dbi dbs);
/** @brief Create a transaction for use with the environment.
*
* The transaction handle may be discarded using #mdb_txn_abort() or #mdb_txn_commit().
* @note Transactions may not span threads; a transaction must only be used by a
* single thread. Also, a thread may only have a single transaction.
* @note A transaction and its cursors must only be used by a single
* thread, and a thread may only have a single transaction at a time.
* If #MDB_NOTLS is in use, this does not apply to read-only transactions.
* @note Cursors may not span transactions; each cursor must be opened and closed
* within a single transaction.
* @param[in] env An environment handle returned by #mdb_env_create()
@ -692,7 +711,7 @@ int mdb_env_set_maxdbs(MDB_env *env, MDB_dbi dbs);
* errors are:
* <ul>
* <li>#MDB_PANIC - a fatal error occurred earlier and the environment
- * must be shut down.
* must be shut down.
* <li>#MDB_MAP_RESIZED - another process wrote data beyond this MDB_env's
* mapsize and the environment must be shut down.
* <li>#MDB_READERS_FULL - a read-only transaction was requested and
@ -728,11 +747,13 @@ void mdb_txn_abort(MDB_txn *txn);
/** @brief Reset a read-only transaction.
*
* This releases the current reader lock but doesn't free the
* transaction handle, allowing it to be used again later by #mdb_txn_renew().
* It otherwise has the same effect as #mdb_txn_abort() but saves some memory
* allocation/deallocation overhead if a thread is going to start a new
* read-only transaction again soon.
* Abort the transaction like #mdb_txn_abort(), but keep the transaction
* handle. #mdb_txn_renew() may reuse the handle. This saves allocation
* overhead if the process will start a new read-only transaction soon,
* and also locking overhead if #MDB_NOTLS is in use. The reader table
* lock is released, but the table slot stays tied to its thread or
* #MDB_txn. Use mdb_txn_abort() to discard a reset handle, and to free
* its lock table slot if MDB_NOTLS is in use.
* All cursors opened within the transaction must be closed before the transaction
* is reset.
* Reader locks generally don't interfere with writers, but they keep old
@ -1043,8 +1064,8 @@ int mdb_del(MDB_txn *txn, MDB_dbi dbi, MDB_val *key, MDB_val *data);
/** @brief Create a cursor handle.
*
* Cursors are associated with a specific transaction and database and
* may not span threads.
* A cursor is associated with a specific transaction and database.
* It must be closed before its transaction ends.
* @param[in] txn A transaction handle returned by #mdb_txn_begin()
* @param[in] dbi A database handle returned by #mdb_dbi_open()
* @param[out] cursor Address where the new #MDB_cursor handle will be stored
@ -1065,8 +1086,9 @@ void mdb_cursor_close(MDB_cursor *cursor);
/** @brief Renew a cursor handle.
*
* Cursors are associated with a specific transaction and database and
* may not span threads. Cursors that are only used in read-only
* A cursor is associated with a specific transaction and database.
* It must be closed before its transaction ends.
* Cursors that are only used in read-only
* transactions may be re-used, to avoid unnecessary malloc/free overhead.
* The cursor may be associated with a new read-only transaction, and
* referencing the same database handle as it was created with.

257
libraries/liblmdb/mdb.c
View file

@ -406,6 +406,8 @@ typedef uint16_t indx_t;
* slot's address is saved in thread-specific data so that subsequent read
* transactions started by the same thread need no further locking to proceed.
*
* If #MDB_NOTLS is set, the slot address is not saved in thread-specific data.
*
* No reader table is used if the database is on a read-only filesystem.
*
* Since the database uses multi-version concurrency control, readers don't
@ -746,7 +748,8 @@ typedef struct MDB_db {
} MDB_db;
/** mdb_dbi_open flags */
#define PERSISTENT_FLAGS 0x7fff
#define MDB_VALID 0x8000 /**< DB handle is valid, for me_dbflags */
#define PERSISTENT_FLAGS (0xffff & ~(MDB_VALID))
#define VALID_FLAGS (MDB_REVERSEKEY|MDB_DUPSORT|MDB_INTEGERKEY|MDB_DUPFIXED|\
MDB_INTEGERDUP|MDB_REVERSEDUP|MDB_CREATE)
@ -830,8 +833,7 @@ struct MDB_txn {
#define DB_DIRTY 0x01 /**< DB was written in this txn */
#define DB_STALE 0x02 /**< DB record is older than txnID */
#define DB_NEW 0x04 /**< DB handle opened in this txn */
#define DB_VALID 0x08 /**< DB handle is valid */
#define MDB_VALID 0x8000 /**< DB handle is valid, for me_dbflags */
#define DB_VALID 0x08 /**< DB handle is valid, see also #MDB_VALID */
/** @} */
/** In write txns, array of cursors for each DB */
MDB_cursor **mt_cursors;
@ -934,10 +936,10 @@ struct MDB_env {
HANDLE me_mfd; /**< just for writing the meta pages */
/** Failed to update the meta page. Probably an I/O error. */
#define MDB_FATAL_ERROR 0x80000000U
/** Read-only Filesystem. Allow read access, no locking. */
#define MDB_ROFS 0x40000000U
/** Some fields are initialized. */
#define MDB_ENV_ACTIVE 0x20000000U
/** me_txkey is set */
#define MDB_ENV_TXKEY 0x10000000U
uint32_t me_flags; /**< @ref mdb_env */
unsigned int me_psize; /**< size of a page, from #GET_PAGESIZE */
unsigned int me_maxreaders; /**< size of the reader table */
@ -963,8 +965,8 @@ struct MDB_env {
MDB_page *me_dpages; /**< list of malloc'd blocks for re-use */
/** IDL of pages that became unused in a write txn */
MDB_IDL me_free_pgs;
/** ID2L of pages that were written during a write txn */
MDB_ID2 me_dirty_list[MDB_IDL_UM_SIZE];
/** ID2L of pages written during a write txn. Length MDB_IDL_UM_SIZE. */
MDB_ID2L me_dirty_list;
/** Max number of freelist items that can fit in a single overflow page */
unsigned int me_maxfree_1pg;
/** Max size of a node on a page */
@ -1083,6 +1085,7 @@ static char *const mdb_errstr[] = {
"MDB_PAGE_FULL: Internal error - page has no more space",
"MDB_MAP_RESIZED: Database contents grew beyond environment mapsize",
"MDB_INCOMPATIBLE: Database flags changed or would change",
"MDB_BAD_RSLOT: Invalid reuse of reader locktable slot",
};
char *
@ -1769,9 +1772,7 @@ mdb_txn_reset0(MDB_txn *txn);
/** Common code for #mdb_txn_begin() and #mdb_txn_renew().
* @param[in] txn the transaction handle to initialize
* @return 0 on success, non-zero on failure. This can only
* fail for read-only transactions, and then only if the
* reader table is full.
* @return 0 on success, non-zero on failure.
*/
static int
mdb_txn_renew0(MDB_txn *txn)
@ -1786,13 +1787,17 @@ mdb_txn_renew0(MDB_txn *txn)
txn->mt_dbxs = env->me_dbxs; /* mostly static anyway */
if (txn->mt_flags & MDB_TXN_RDONLY) {
if (env->me_flags & MDB_ROFS) {
if (!env->me_txns) {
i = mdb_env_pick_meta(env);
txn->mt_txnid = env->me_metas[i]->mm_txnid;
txn->mt_u.reader = NULL;
} else {
MDB_reader *r = pthread_getspecific(env->me_txkey);
if (!r) {
MDB_reader *r = (env->me_flags & MDB_NOTLS) ? txn->mt_u.reader :
pthread_getspecific(env->me_txkey);
if (r) {
if (r->mr_pid != env->me_pid || r->mr_txnid != (txnid_t)-1)
return MDB_BAD_RSLOT;
} else {
pid_t pid = env->me_pid;
pthread_t tid = pthread_self();
@ -1812,7 +1817,8 @@ mdb_txn_renew0(MDB_txn *txn)
env->me_numreaders = env->me_txns->mti_numreaders;
UNLOCK_MUTEX_R(env);
r = &env->me_txns->mti_readers[i];
if ((rc = pthread_setspecific(env->me_txkey, r)) != 0) {
if (!(env->me_flags & MDB_NOTLS) &&
(rc = pthread_setspecific(env->me_txkey, r)) != 0) {
env->me_txns->mti_readers[i].mr_pid = 0;
return rc;
}
@ -1844,7 +1850,8 @@ mdb_txn_renew0(MDB_txn *txn)
/* Copy the DB info and flags */
memcpy(txn->mt_dbs, env->me_metas[txn->mt_toggle]->mm_dbs, 2 * sizeof(MDB_db));
for (i=2; i<txn->mt_numdbs; i++) {
txn->mt_dbs[i].md_flags = x = env->me_dbflags[i];
x = env->me_dbflags[i];
txn->mt_dbs[i].md_flags = x & PERSISTENT_FLAGS;
txn->mt_dbflags[i] = (x & MDB_VALID) ? DB_VALID|DB_STALE : 0;
}
txn->mt_dbflags[0] = txn->mt_dbflags[1] = DB_VALID;
@ -1862,7 +1869,7 @@ mdb_txn_renew(MDB_txn *txn)
{
int rc;
if (! (txn && (txn->mt_flags & MDB_TXN_RDONLY)))
if (!txn || txn->mt_numdbs || !(txn->mt_flags & MDB_TXN_RDONLY))
return EINVAL;
if (txn->mt_env->me_flags & MDB_FATAL_ERROR) {
@ -1979,6 +1986,7 @@ mdb_txn_begin(MDB_env *env, MDB_txn *parent, unsigned int flags, MDB_txn **ret)
}
/** Common code for #mdb_txn_reset() and #mdb_txn_abort().
* May be called twice for readonly txns: First reset it, then abort.
* @param[in] txn the transaction handle to reset
*/
static void
@ -1998,8 +2006,12 @@ mdb_txn_reset0(MDB_txn *txn)
}
if (F_ISSET(txn->mt_flags, MDB_TXN_RDONLY)) {
if (!(env->me_flags & MDB_ROFS))
if (txn->mt_u.reader) {
txn->mt_u.reader->mr_txnid = (txnid_t)-1;
if (!(env->me_flags & MDB_NOTLS))
txn->mt_u.reader = NULL; /* txn does not own reader */
}
txn->mt_numdbs = 0; /* mark txn as reset, do not close DBs again */
} else {
MDB_page *dp;
@ -2061,6 +2073,10 @@ mdb_txn_reset(MDB_txn *txn)
txn->mt_txnid, (txn->mt_flags & MDB_TXN_RDONLY) ? 'r' : 'w',
(void *) txn, (void *)txn->mt_env, txn->mt_dbs[MAIN_DBI].md_root);
/* This call is only valid for read-only txns */
if (!(txn->mt_flags & MDB_TXN_RDONLY))
return;
mdb_txn_reset0(txn);
}
@ -2078,6 +2094,10 @@ mdb_txn_abort(MDB_txn *txn)
mdb_txn_abort(txn->mt_child);
mdb_txn_reset0(txn);
/* Free reader slot tied to this txn (if MDB_NOTLS && writable FS) */
if ((txn->mt_flags & MDB_TXN_RDONLY) && txn->mt_u.reader)
txn->mt_u.reader->mr_pid = 0;
free(txn);
}
@ -2769,13 +2789,8 @@ mdb_env_create(MDB_env **env)
if (!e)
return ENOMEM;
e->me_free_pgs = mdb_midl_alloc();
if (!e->me_free_pgs) {
free(e);
return ENOMEM;
}
e->me_maxreaders = DEFAULT_READERS;
e->me_maxdbs = 2;
e->me_maxdbs = e->me_numdbs = 2;
e->me_fd = INVALID_HANDLE_VALUE;
e->me_lfd = INVALID_HANDLE_VALUE;
e->me_mfd = INVALID_HANDLE_VALUE;
@ -3192,65 +3207,69 @@ mdb_hash_hex(MDB_val *val, char *hexbuf)
* @param[in] lpath The pathname of the file used for the lock region.
* @param[in] mode The Unix permissions for the file, if we create it.
* @param[out] excl Resulting file lock type: -1 none, 0 shared, 1 exclusive
* @param[in,out] excl In -1, out lock type: -1 none, 0 shared, 1 exclusive
* @return 0 on success, non-zero on failure.
*/
static int
mdb_env_setup_locks(MDB_env *env, char *lpath, int mode, int *excl)
{
#ifdef _WIN32
# define MDB_ERRCODE_ROFS ERROR_WRITE_PROTECT
#else
# define MDB_ERRCODE_ROFS EROFS
#ifdef O_CLOEXEC /* Linux: Open file and set FD_CLOEXEC atomically */
# define MDB_CLOEXEC O_CLOEXEC
#else
int fdflags;
# define MDB_CLOEXEC 0
#endif
#endif
int rc;
off_t size, rsize;
*excl = -1;
#ifdef _WIN32
if ((env->me_lfd = CreateFile(lpath, GENERIC_READ|GENERIC_WRITE,
env->me_lfd = CreateFile(lpath, GENERIC_READ|GENERIC_WRITE,
FILE_SHARE_READ|FILE_SHARE_WRITE, NULL, OPEN_ALWAYS,
FILE_ATTRIBUTE_NORMAL, NULL)) == INVALID_HANDLE_VALUE) {
rc = ErrCode();
if (rc == ERROR_WRITE_PROTECT && (env->me_flags & MDB_RDONLY)) {
env->me_flags |= MDB_ROFS;
return MDB_SUCCESS;
}
goto fail_errno;
}
/* Try to get exclusive lock. If we succeed, then
* nobody is using the lock region and we should initialize it.
*/
if ((rc = mdb_env_excl_lock(env, excl))) goto fail;
size = GetFileSize(env->me_lfd, NULL);
FILE_ATTRIBUTE_NORMAL, NULL);
#else
#if !(O_CLOEXEC)
{
int fdflags;
if ((env->me_lfd = open(lpath, O_RDWR|O_CREAT, mode)) == -1) {
rc = ErrCode();
if (rc == EROFS && (env->me_flags & MDB_RDONLY)) {
env->me_flags |= MDB_ROFS;
return MDB_SUCCESS;
}
goto fail_errno;
}
/* Lose record locks when exec*() */
if ((fdflags = fcntl(env->me_lfd, F_GETFD) | FD_CLOEXEC) >= 0)
fcntl(env->me_lfd, F_SETFD, fdflags);
}
#else /* O_CLOEXEC on Linux: Open file and set FD_CLOEXEC atomically */
if ((env->me_lfd = open(lpath, O_RDWR|O_CREAT|O_CLOEXEC, mode)) == -1) {
env->me_lfd = open(lpath, O_RDWR|O_CREAT|MDB_CLOEXEC, mode);
#endif
if (env->me_lfd == INVALID_HANDLE_VALUE) {
rc = ErrCode();
if (rc == EROFS && (env->me_flags & MDB_RDONLY)) {
env->me_flags |= MDB_ROFS;
if (rc == MDB_ERRCODE_ROFS && (env->me_flags & MDB_RDONLY)) {
return MDB_SUCCESS;
}
goto fail_errno;
}
#if ! ((MDB_CLOEXEC) || defined(_WIN32))
/* Lose record locks when exec*() */
if ((fdflags = fcntl(env->me_lfd, F_GETFD) | FD_CLOEXEC) >= 0)
fcntl(env->me_lfd, F_SETFD, fdflags);
#endif
if (!(env->me_flags & MDB_NOTLS)) {
rc = pthread_key_create(&env->me_txkey, mdb_env_reader_dest);
if (rc)
goto fail;
env->me_flags |= MDB_ENV_TXKEY;
#ifdef _WIN32
/* Windows TLS callbacks need help finding their TLS info. */
if (mdb_tls_nkeys >= MAX_TLS_KEYS) {
rc = MDB_TLS_FULL;
goto fail;
}
mdb_tls_keys[mdb_tls_nkeys++] = env->me_txkey;
#endif
}
/* Try to get exclusive lock. If we succeed, then
* nobody is using the lock region and we should initialize it.
*/
if ((rc = mdb_env_excl_lock(env, excl))) goto fail;
#ifdef _WIN32
size = GetFileSize(env->me_lfd, NULL);
#else
size = lseek(env->me_lfd, 0, SEEK_END);
#endif
rsize = (env->me_maxreaders-1) * sizeof(MDB_reader) + sizeof(MDB_txninfo);
@ -3406,12 +3425,12 @@ fail:
* environment and re-opening it with the new flags.
*/
#define CHANGEABLE (MDB_NOSYNC|MDB_NOMETASYNC|MDB_MAPASYNC)
#define CHANGELESS (MDB_FIXEDMAP|MDB_NOSUBDIR|MDB_RDONLY|MDB_WRITEMAP)
#define CHANGELESS (MDB_FIXEDMAP|MDB_NOSUBDIR|MDB_RDONLY|MDB_WRITEMAP|MDB_NOTLS)
int
mdb_env_open(MDB_env *env, const char *path, unsigned int flags, mdb_mode_t mode)
{
int oflags, rc, len, excl;
int oflags, rc, len, excl = -1;
char *lpath, *dpath;
if (env->me_fd!=INVALID_HANDLE_VALUE || (flags & ~(CHANGEABLE|CHANGELESS)))
@ -3436,11 +3455,27 @@ mdb_env_open(MDB_env *env, const char *path, unsigned int flags, mdb_mode_t mode
sprintf(dpath, "%s" DATANAME, path);
}
rc = MDB_SUCCESS;
flags |= env->me_flags;
/* silently ignore WRITEMAP if we're only getting read access */
if (F_ISSET(flags, MDB_RDONLY|MDB_WRITEMAP))
flags ^= MDB_WRITEMAP;
if (flags & MDB_RDONLY) {
/* silently ignore WRITEMAP when we're only getting read access */
flags &= ~MDB_WRITEMAP;
} else {
if (!((env->me_free_pgs = mdb_midl_alloc()) &&
(env->me_dirty_list = calloc(MDB_IDL_UM_SIZE, sizeof(MDB_ID2)))))
rc = ENOMEM;
}
env->me_flags = flags |= MDB_ENV_ACTIVE;
if (rc)
goto leave;
env->me_path = strdup(path);
env->me_dbxs = calloc(env->me_maxdbs, sizeof(MDB_dbx));
env->me_dbflags = calloc(env->me_maxdbs, sizeof(uint16_t));
if (!(env->me_dbxs && env->me_path && env->me_dbflags)) {
rc = ENOMEM;
goto leave;
}
rc = mdb_env_setup_locks(env, lpath, mode, &excl);
if (rc)
@ -3490,29 +3525,9 @@ mdb_env_open(MDB_env *env, const char *path, unsigned int flags, mdb_mode_t mode
}
}
DPRINTF("opened dbenv %p", (void *) env);
rc = pthread_key_create(&env->me_txkey, mdb_env_reader_dest);
if (rc)
goto leave;
env->me_numdbs = 2; /* this notes that me_txkey was set */
#ifdef _WIN32
/* Windows TLS callbacks need help finding their TLS info. */
if (mdb_tls_nkeys < MAX_TLS_KEYS)
mdb_tls_keys[mdb_tls_nkeys++] = env->me_txkey;
else {
rc = MDB_TLS_FULL;
goto leave;
}
#endif
if (excl > 0) {
rc = mdb_env_share_locks(env, &excl);
if (rc)
goto leave;
}
env->me_dbxs = calloc(env->me_maxdbs, sizeof(MDB_dbx));
env->me_dbflags = calloc(env->me_maxdbs, sizeof(uint16_t));
env->me_path = strdup(path);
if (!env->me_dbxs || !env->me_dbflags || !env->me_path)
rc = ENOMEM;
}
leave:
@ -3535,8 +3550,11 @@ mdb_env_close0(MDB_env *env, int excl)
free(env->me_dbflags);
free(env->me_dbxs);
free(env->me_path);
free(env->me_dirty_list);
if (env->me_free_pgs)
mdb_midl_free(env->me_free_pgs);
if (env->me_numdbs) {
if (env->me_flags & MDB_ENV_TXKEY) {
pthread_key_delete(env->me_txkey);
#ifdef _WIN32
/* Delete our key from the global list */
@ -3602,7 +3620,7 @@ mdb_env_close0(MDB_env *env, int excl)
close(env->me_lfd);
}
env->me_flags &= ~MDB_ENV_ACTIVE;
env->me_flags &= ~(MDB_ENV_ACTIVE|MDB_ENV_TXKEY);
}
int
@ -3661,7 +3679,7 @@ mdb_env_copy(MDB_env *env, const char *path)
if (rc)
goto leave;
if (!(env->me_flags & MDB_ROFS)) {
if (env->me_txns) {
/* We must start the actual read txn after blocking writers */
mdb_txn_reset0(txn);
@ -3686,7 +3704,7 @@ mdb_env_copy(MDB_env *env, const char *path)
rc = write(newfd, env->me_map, wsize);
rc = (rc == (int)wsize) ? MDB_SUCCESS : ErrCode();
#endif
if (! (env->me_flags & MDB_ROFS))
if (env->me_txns)
UNLOCK_MUTEX_W(env);
if (rc)
@ -3752,7 +3770,6 @@ mdb_env_close(MDB_env *env)
}
mdb_env_close0(env, 0);
mdb_midl_free(env->me_free_pgs);
free(env);
}
@ -4111,6 +4128,28 @@ mdb_page_search_root(MDB_cursor *mc, MDB_val *key, int modify)
return MDB_SUCCESS;
}
/** Search for the lowest key under the current branch page.
* This just bypasses a NUMKEYS check in the current page
* before calling mdb_page_search_root(), because the callers
* are all in situations where the current page is known to
* be underfilled.
*/
static int
mdb_page_search_lowest(MDB_cursor *mc)
{
MDB_page *mp = mc->mc_pg[mc->mc_top];
MDB_node *node = NODEPTR(mp, 0);
int rc;
if ((rc = mdb_page_get(mc->mc_txn, NODEPGNO(node), &mp)))
return rc;
mc->mc_ki[mc->mc_top] = 0;
if ((rc = mdb_cursor_push(mc, mp)))
return rc;
return mdb_page_search_root(mc, NULL, 0);
}
/** Search for the page a given key should be in.
* Pushes parent pages on the cursor stack. This function just sets up
* the search; it finds the root page for \b mc's database and sets this
@ -4688,19 +4727,19 @@ mdb_cursor_last(MDB_cursor *mc, MDB_val *key, MDB_val *data)
if (!(mc->mc_flags & C_EOF)) {
if (!(mc->mc_flags & C_INITIALIZED) || mc->mc_top) {
MDB_val lkey;
if (!(mc->mc_flags & C_INITIALIZED) || mc->mc_top) {
MDB_val lkey;
lkey.mv_size = MDB_MAXKEYSIZE+1;
lkey.mv_data = NULL;
rc = mdb_page_search(mc, &lkey, 0);
if (rc != MDB_SUCCESS)
return rc;
}
assert(IS_LEAF(mc->mc_pg[mc->mc_top]));
lkey.mv_size = MDB_MAXKEYSIZE+1;
lkey.mv_data = NULL;
rc = mdb_page_search(mc, &lkey, 0);
if (rc != MDB_SUCCESS)
return rc;
}
assert(IS_LEAF(mc->mc_pg[mc->mc_top]));
mc->mc_ki[mc->mc_top] = NUMKEYS(mc->mc_pg[mc->mc_top]) - 1;
}
mc->mc_flags |= C_INITIALIZED|C_EOF;
leaf = NODEPTR(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top]);
@ -5823,13 +5862,19 @@ mdb_cursor_open(MDB_txn *txn, MDB_dbi dbi, MDB_cursor **ret)
int
mdb_cursor_renew(MDB_txn *txn, MDB_cursor *mc)
{
unsigned flags;
if (txn == NULL || mc == NULL || mc->mc_dbi >= txn->mt_numdbs)
return EINVAL;
if (txn->mt_cursors)
return EINVAL;
flags = mc->mc_flags;
mdb_cursor_init(mc, txn, mc->mc_dbi, mc->mc_xcursor);
mc->mc_flags |= (flags & C_ALLOCD);
return MDB_SUCCESS;
}
@ -6001,7 +6046,7 @@ mdb_node_move(MDB_cursor *csrc, MDB_cursor *cdst)
unsigned int snum = csrc->mc_snum;
MDB_node *s2;
/* must find the lowest key below src */
mdb_page_search_root(csrc, NULL, 0);
mdb_page_search_lowest(csrc);
if (IS_LEAF2(csrc->mc_pg[csrc->mc_top])) {
key.mv_size = csrc->mc_db->md_pad;
key.mv_data = LEAF2KEY(csrc->mc_pg[csrc->mc_top], 0, key.mv_size);
@ -6024,7 +6069,7 @@ mdb_node_move(MDB_cursor *csrc, MDB_cursor *cdst)
MDB_node *s2;
MDB_val bkey;
/* must find the lowest key below dst */
mdb_page_search_root(cdst, NULL, 0);
mdb_page_search_lowest(cdst);
if (IS_LEAF2(cdst->mc_pg[cdst->mc_top])) {
bkey.mv_size = cdst->mc_db->md_pad;
bkey.mv_data = LEAF2KEY(cdst->mc_pg[cdst->mc_top], 0, bkey.mv_size);
@ -6188,7 +6233,7 @@ mdb_page_merge(MDB_cursor *csrc, MDB_cursor *cdst)
unsigned int snum = csrc->mc_snum;
MDB_node *s2;
/* must find the lowest key below src */
mdb_page_search_root(csrc, NULL, 0);
mdb_page_search_lowest(csrc);
if (IS_LEAF2(csrc->mc_pg[csrc->mc_top])) {
key.mv_size = csrc->mc_db->md_pad;
key.mv_data = LEAF2KEY(csrc->mc_pg[csrc->mc_top], 0, key.mv_size);
@ -6295,6 +6340,7 @@ mdb_rebalance(MDB_cursor *mc)
unsigned int ptop, minkeys;
MDB_cursor mn;
minkeys = 1 + (IS_BRANCH(mc->mc_pg[mc->mc_top]));
#if MDB_DEBUG
{
pgno_t pgno;
@ -6305,7 +6351,8 @@ mdb_rebalance(MDB_cursor *mc)
}
#endif
if (PAGEFILL(mc->mc_txn->mt_env, mc->mc_pg[mc->mc_top]) >= FILL_THRESHOLD) {
if (PAGEFILL(mc->mc_txn->mt_env, mc->mc_pg[mc->mc_top]) >= FILL_THRESHOLD &&
NUMKEYS(mc->mc_pg[mc->mc_top]) >= minkeys) {
#if MDB_DEBUG
pgno_t pgno;
COPY_PGNO(pgno, mc->mc_pg[mc->mc_top]->mp_pgno);
@ -6317,6 +6364,10 @@ mdb_rebalance(MDB_cursor *mc)
if (mc->mc_snum < 2) {
MDB_page *mp = mc->mc_pg[0];
if (IS_SUBP(mp)) {
DPUTS("Can't rebalance a subpage, ignoring");
return MDB_SUCCESS;
}
if (NUMKEYS(mp) == 0) {
DPUTS("tree is completely empty");
mc->mc_db->md_root = P_INVALID;