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mdbx: rework posix-lck.

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Change-Id: Icdd61731424b0d591fd28da0468b9623d079c94a
This commit is contained in:
Leo Yuriev 2017-04-23 13:52:53 +03:00
parent 6b4f92b22e
commit 11ac6a02ff
2 changed files with 68 additions and 30 deletions
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94
src/lck-posix.c
View File

@ -49,7 +49,31 @@ void __attribute__((destructor)) mdbx_global_destructor(void) {
/*----------------------------------------------------------------------------*/
/* lck */
static int mdbx_lck_op(mdbx_filehandle_t fd, int op, int lck, off_t offset);
#ifndef OFF_T_MAX
#define OFF_T_MAX (sizeof(off_t) > 4 ? INT64_MAX : INT32_MAX)
#endif
#define LCK_WHOLE OFF_T_MAX
static int mdbx_lck_op(mdbx_filehandle_t fd, int op, int lck, off_t offset,
off_t len) {
for (;;) {
int rc;
struct flock lock_op;
memset(&lock_op, 0, sizeof(lock_op));
lock_op.l_type = lck;
lock_op.l_whence = SEEK_SET;
lock_op.l_start = offset;
lock_op.l_len = len;
if ((rc = fcntl(fd, op, &lock_op)) == 0) {
if (op == F_GETLK && lock_op.l_type != F_UNLCK)
rc = -lock_op.l_pid;
} else if ((rc = errno) == EINTR) {
continue;
}
return rc;
}
}
static int mdbx_mutex_failed(MDB_env *env, pthread_mutex_t *mutex, int rc);
int mdbx_lck_init(MDB_env *env) {
@ -93,7 +117,8 @@ bailout:
void mdbx_lck_destroy(MDB_env *env) {
if (env->me_lfd != INVALID_HANDLE_VALUE) {
/* try get exclusive access */
if (env->me_txns && mdbx_lck_op(env->me_lfd, F_SETLK, F_WRLCK, 0) == 0) {
if (env->me_txns &&
mdbx_lck_op(env->me_lfd, F_SETLK, F_WRLCK, 0, LCK_WHOLE) == 0) {
/* got exclusive, drown mutexes */
int rc = pthread_mutex_destroy(&env->me_txns->mti_rmutex);
if (rc == 0)
@ -140,18 +165,20 @@ void mdbx_txn_unlock(MDB_env *env) {
mdbx_panic("%s() failed: errcode %d\n", mdbx_func_, rc);
}
int mdbx_lck_seize(MDB_env *env) {
static int internal_seize_lck(int lfd) {
assert(lfd != INVALID_HANDLE_VALUE);
/* try exclusive access */
int rc = mdbx_lck_op(env->me_lfd, F_SETLK, F_WRLCK, 0);
int rc = mdbx_lck_op(lfd, F_SETLK, F_WRLCK, 0, 1);
if (rc == 0)
/* got exclusive */
return MDBX_RESULT_TRUE;
if (rc == EAGAIN || rc == EACCES || rc == EBUSY) {
/* get shared access */
rc = mdbx_lck_op(env->me_lfd, F_SETLKW, F_RDLCK, 0);
rc = mdbx_lck_op(lfd, F_SETLKW, F_RDLCK, 0, 1);
if (rc == 0) {
/* got shared, try exclusive again */
rc = mdbx_lck_op(env->me_lfd, F_SETLK, F_WRLCK, 0);
rc = mdbx_lck_op(lfd, F_SETLK, F_WRLCK, 0, 1);
if (rc == 0)
/* now got exclusive */
return MDBX_RESULT_TRUE;
@ -160,20 +187,46 @@ int mdbx_lck_seize(MDB_env *env) {
return MDBX_RESULT_FALSE;
}
}
assert(rc != MDBX_RESULT_FALSE && rc != MDBX_RESULT_TRUE);
assert(MDBX_IS_ERROR(rc));
return rc;
}
int mdbx_lck_seize(MDB_env *env) {
assert(env->me_fd != INVALID_HANDLE_VALUE);
if (env->me_lfd == INVALID_HANDLE_VALUE) {
/* LY: without-lck mode (e.g. on read-only filesystem) */
int rc = mdbx_lck_op(env->me_fd, F_SETLK, F_RDLCK, 0, LCK_WHOLE);
if (rc != 0) {
mdbx_error("%s(%s) failed: errcode %u", mdbx_func_, "without-lck", rc);
return rc;
}
return MDBX_RESULT_FALSE;
}
if ((env->me_flags & MDB_RDONLY) == 0) {
/* Check that another process don't operates in without-lck mode. */
int rc = mdbx_lck_op(env->me_fd, F_SETLK, F_WRLCK, env->me_pid, 1);
if (rc != 0) {
mdbx_error("%s(%s) failed: errcode %u", mdbx_func_,
"lock-against-without-lck", rc);
return rc;
}
}
return internal_seize_lck(env->me_lfd);
}
int mdbx_lck_downgrade(MDB_env *env) {
return mdbx_lck_op(env->me_lfd, F_SETLK, F_RDLCK, 0);
return mdbx_lck_op(env->me_lfd, F_SETLK, F_RDLCK, 0, 1);
}
int mdbx_rpid_set(MDB_env *env) {
return mdbx_lck_op(env->me_lfd, F_SETLK, F_WRLCK, env->me_pid);
return mdbx_lck_op(env->me_lfd, F_SETLK, F_WRLCK, env->me_pid, 1);
}
int mdbx_rpid_clear(MDB_env *env) {
return mdbx_lck_op(env->me_lfd, F_SETLKW, F_UNLCK, env->me_pid);
return mdbx_lck_op(env->me_lfd, F_SETLKW, F_UNLCK, env->me_pid, 1);
}
/* Checks reader by pid.
@ -183,7 +236,7 @@ int mdbx_rpid_clear(MDB_env *env) {
* MDBX_RESULT_FALSE, if pid is dead (lock acquired)
* or otherwise the errcode. */
int mdbx_rpid_check(MDB_env *env, mdbx_pid_t pid) {
int rc = mdbx_lck_op(env->me_lfd, F_GETLK, F_WRLCK, pid);
int rc = mdbx_lck_op(env->me_lfd, F_GETLK, F_WRLCK, pid, 1);
if (rc == 0)
return MDBX_RESULT_FALSE;
if (rc < 0 && -rc == pid)
@ -191,25 +244,6 @@ int mdbx_rpid_check(MDB_env *env, mdbx_pid_t pid) {
return rc;
}
static int mdbx_lck_op(mdbx_filehandle_t fd, int op, int lck, off_t offset) {
for (;;) {
int rc;
struct flock lock_op;
memset(&lock_op, 0, sizeof(lock_op));
lock_op.l_type = lck;
lock_op.l_whence = SEEK_SET;
lock_op.l_start = offset;
lock_op.l_len = 1;
if ((rc = fcntl(fd, op, &lock_op)) == 0) {
if (op == F_GETLK && lock_op.l_type != F_UNLCK)
rc = -lock_op.l_pid;
} else if ((rc = errno) == EINTR) {
continue;
}
return rc;
}
}
#if !__GLIBC_PREREQ(2, 12) && !defined(pthread_mutex_consistent)
#define pthread_mutex_consistent(mutex) pthread_mutex_consistent_np(mutex)
#endif

4
test/base.h
View File

@ -63,5 +63,9 @@
#include <intrin.h>
#endif
#if defined(__i386__) || defined(__x86_64__)
#include <x86intrin.h>
#endif
#include "../mdbx.h"
#include "../src/defs.h"