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Protect updating of router when rotating.

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When rotating, all state variables of router are now updated while
protected by the router->binlog_lock lock.
This commit is contained in:
Johan Wikman
2016-01-28 14:17:57 +02:00
parent 0deffbf2f2
commit d9b022db10
3 changed files with 77 additions and 40 deletions
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100
server/modules/routing/binlog/blr_file.c
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@ -189,59 +189,77 @@ blr_file_rotate(ROUTER_INSTANCE *router, char *file, uint64_t pos)
* binlog files need an initial 4 magic bytes at the start. blr_file_add_magic()
* adds them.
*
* @param router The router instance
* @param fd file descriptor to the open binlog file
* @return Nothing
* @param fd file descriptor to the open binlog file
* @return True if the magic string could be written to the file.
*/
static void
blr_file_add_magic(ROUTER_INSTANCE *router, int fd)
static bool
blr_file_add_magic(int fd)
{
unsigned char magic[] = BINLOG_MAGIC;
static const unsigned char magic[] = BINLOG_MAGIC;
write(fd, magic, 4);
router->current_pos = 4; /* Initial position after the magic number */
router->binlog_position = 4; /* Initial position after the magic number */
router->current_safe_event = 4;
router->last_written = 0;
ssize_t written = write(fd, magic, BINLOG_MAGIC_SIZE);
return written == BINLOG_MAGIC_SIZE;
}
/**
* Create a new binlog file for the router to use.
*
* @param router The router instance
* @param file The binlog file name
* @return Non-zero if the fie creation succeeded
* @param router The router instance
* @param file The binlog file name
* @return Non-zero if the fie creation succeeded
*/
static int
blr_file_create(ROUTER_INSTANCE *router, char *file)
{
char path[PATH_MAX + 1] = "";
int fd;
int created = 0;
char err_msg[STRERROR_BUFLEN];
strcpy(path, router->binlogdir);
strcat(path, "/");
strcat(path, file);
char path[PATH_MAX + 1] = "";
if ((fd = open(path, O_RDWR|O_CREAT, 0666)) != -1)
{
blr_file_add_magic(router,fd);
}
else
{
char err_msg[STRERROR_BUFLEN];
strcpy(path, router->binlogdir);
strcat(path, "/");
strcat(path, file);
MXS_ERROR("%s: Failed to create binlog file %s, %s.",
int fd = open(path, O_RDWR|O_CREAT, 0666);
if (fd != -1)
{
if (blr_file_add_magic(fd))
{
close(router->binlog_fd);
spinlock_acquire(&router->binlog_lock);
strncpy(router->binlog_name, file, BINLOG_FNAMELEN);
router->binlog_fd = fd;
router->current_pos = BINLOG_MAGIC_SIZE; /* Initial position after the magic number */
router->binlog_position = BINLOG_MAGIC_SIZE;
router->current_safe_event = BINLOG_MAGIC_SIZE;
router->last_written = 0;
spinlock_release(&router->binlog_lock);
created = 1;
}
else
{
MXS_ERROR("%s: Failed to write magic string to created binlog file %s, %s.",
router->service->name, path, strerror_r(errno, err_msg, sizeof(err_msg)));
close(fd);
if (!unlink(path))
{
MXS_ERROR("%s: Failed to delete file %s, %s.",
router->service->name, path, strerror_r(errno, err_msg, sizeof(err_msg)));
return 0;
}
fsync(fd);
close(router->binlog_fd);
spinlock_acquire(&router->binlog_lock);
strncpy(router->binlog_name, file, BINLOG_FNAMELEN);
router->binlog_fd = fd;
spinlock_release(&router->binlog_lock);
return 1;
}
}
}
else
{
MXS_ERROR("%s: Failed to create binlog file %s, %s.",
router->service->name, path, strerror_r(errno, err_msg, sizeof(err_msg)));
}
return created;
}
/**
@ -273,7 +291,15 @@ int fd;
router->current_pos = lseek(fd, 0L, SEEK_END);
if (router->current_pos < 4) {
if (router->current_pos == 0) {
blr_file_add_magic(router, fd);
if (blr_file_add_magic(fd))
{
router->current_pos = BINLOG_MAGIC_SIZE;
router->binlog_position = BINLOG_MAGIC_SIZE;
router->current_safe_event = BINLOG_MAGIC_SIZE;
router->last_written = 0;
} else {
MXS_ERROR("%s: Could not write magic to binlog file.", router->service->name);
}
} else {
/* If for any reason the file's length is between 1 and 3 bytes
* then report an error. */