mirror of
https://github.com/schoebel/mars
synced 2024-12-15 19:25:51 +00:00
light: fix logfile rotation
The old code had races, migitated by long timeouts. The new code has strictly no dependencies from realtime.
This commit is contained in:
Thomas Schoebel-Theuer
parent
899b0a5743
commit
a036a01188
@ -97,7 +97,6 @@ struct mars_rotate {
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struct mars_limiter file_limiter;
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struct semaphore inf_mutex;
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int inf_prev_sequence;
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long long switchover_timeout;
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long long flip_start;
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loff_t dev_size;
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loff_t total_space;
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@ -375,45 +374,6 @@ done:
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#define MARS_DELIM ','
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static
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char *_parse_versionlink(const char *str, loff_t *pos)
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{
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char *res = NULL;
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const char *tmp;
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int count;
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int status;
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*pos = 0;
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while (*str && *str++ != MARS_DELIM) {
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// empty
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}
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tmp = str;
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count = 0;
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while (*tmp && *tmp != MARS_DELIM) {
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tmp++;
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count++;
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}
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res = brick_string_alloc(count + 1);
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if (unlikely(!res)) {
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MARS_DBG("bad alloc\n");
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goto done;
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}
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strncpy(res, str, count);
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res[count] = '\0';
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status = sscanf(tmp, ",%lld", pos);
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if (unlikely(status != 1)) {
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MARS_DBG("status = %d\n", status);
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brick_string_free(res);
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res = NULL;
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}
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done:
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return res;
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}
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static int _parse_args(struct mars_dent *dent, char *str, int count)
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{
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int i;
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@ -1525,75 +1485,206 @@ void _create_new_logfile(const char *path)
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}
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}
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static
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int _check_versionlink(struct mars_global *global, const char *parent_path, int sequence, loff_t target_end_pos)
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#define skip_part(s) _skip_part(s, ',', ';')
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#define skip_sect(s) _skip_part(s, ';', 0)
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static inline
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int _skip_part(const char *str, const char del1, const char del2)
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{
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char *my_version = NULL;
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char *my_version_link = NULL;
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char *other_version = NULL;
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char *other_version_link = NULL;
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char *from_host = NULL;
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loff_t pos = 0;
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int status = -ENOMEM;
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int len = 0;
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while (str[len] && str[len] != del1 && (!del2 || str[len] != del2))
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len++;
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return len;
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}
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my_version = path_make("%s/version-%09d-%s", parent_path, sequence, my_id());
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if (!my_version) {
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MARS_WRN("out of memory");
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goto out;
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static inline
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int skip_dir(const char *str)
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{
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int len = 0;
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int res = 0;
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for (len = 0; str[len]; len++)
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if (str[len] == '/')
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res = len + 1;
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return res;
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}
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static
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int parse_logfile_name(const char *str, int *seq, const char **host)
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{
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char *_host;
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int count;
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int len = 0;
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int len_host;
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*seq = 0;
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*host = NULL;
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count = sscanf(str, "log-%d-%n", seq, &len);
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if (unlikely(count != 1)) {
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MARS_ERR("bad logfile name '%s', count=%d, len=%d\n", str, count, len);
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return 0;
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}
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status = -ENOENT;
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my_version_link = mars_readlink(my_version);
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if (!my_version_link) {
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MARS_WRN("cannot find my own version symlink '%s'\n", my_version);
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goto out;
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_host = brick_strdup(str + len);
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if (unlikely(!_host)) {
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MARS_ERR("no MEM\n");
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return 0;
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}
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from_host = _parse_versionlink(my_version_link, &pos);
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if (!from_host) {
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MARS_WRN("cannot parse '%s'\n", my_version_link);
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goto out;
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len_host = skip_part(_host);
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_host[len_host] = '\0';
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*host = _host;
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len += len_host;
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return len;
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}
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static
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const char *get_replaylink(const char *parent_path, const char *host, const char **linkpath)
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{
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const char * _linkpath = path_make("%s/replay-%s", parent_path, host);
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*linkpath = _linkpath;
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if (unlikely(!_linkpath)) {
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MARS_ERR("no MEM\n");
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return NULL;
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}
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return mars_readlink(_linkpath);
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}
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static
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const char *get_versionlink(const char *parent_path, int seq, const char *host, const char **linkpath)
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{
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const char * _linkpath = path_make("%s/version-%09d-%s", parent_path, seq, host);
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*linkpath = _linkpath;
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if (unlikely(!_linkpath)) {
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MARS_ERR("no MEM\n");
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return NULL;
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}
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return mars_readlink(_linkpath);
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}
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static
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bool is_switchover_possible(const char *parent_path, const char *old_log_path, const char *new_log_path)
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{
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const char *old_log_name = old_log_path + skip_dir(old_log_path);
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const char *new_log_name = new_log_path + skip_dir(new_log_path);
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const char *old_host = NULL;
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const char *new_host = NULL;
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const char *own_versionlink_path = NULL;
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const char *old_versionlink_path = NULL;
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const char *new_versionlink_path = NULL;
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const char *own_versionlink = NULL;
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const char *old_versionlink = NULL;
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const char *new_versionlink = NULL;
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const char *own_replaylink_path = NULL;
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const char *own_replaylink = NULL;
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int old_log_seq;
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int new_log_seq;
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int own_r_offset;
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int own_v_offset;
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int own_r_len;
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int own_v_len;
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int len1;
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int len2;
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int offs2;
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bool res = false;
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if (unlikely(!parse_logfile_name(old_log_name, &old_log_seq, &old_host)))
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goto done;
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if (unlikely(!parse_logfile_name(new_log_name, &new_log_seq, &new_host)))
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goto done;
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// check: are the sequence numbers contiguous?
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if (unlikely(new_log_seq != old_log_seq + 1)) {
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MARS_INF("sequence numbers are not contiguous (%d != %d + 1), old_log_path='%s' new_log_path='%s'\n", new_log_seq, old_log_seq, old_log_path, new_log_path);
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goto done;
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}
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if (!strcmp(from_host, my_id())) {
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MARS_DBG("found version stemming from myself, no check of other version necessary.\n");
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status = 1;
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if (unlikely(pos != target_end_pos)) {
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MARS_WRN("pos = %lld != target_end_pos = %lld\n", pos, target_end_pos);
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status = 0;
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}
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goto out;
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// fetch all the versionlinks and test for their existence.
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own_versionlink = get_versionlink(parent_path, old_log_seq, my_id(), &own_versionlink_path);
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if (unlikely(!own_versionlink)) {
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MARS_INF("cannot read my own versionlink '%s'\n", SAFE_STR(own_versionlink_path));
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goto done;
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}
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old_versionlink = get_versionlink(parent_path, old_log_seq, old_host, &old_versionlink_path);
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if (unlikely(!old_versionlink)) {
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MARS_INF("cannot read old versionlink '%s'\n", SAFE_STR(old_versionlink_path));
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goto done;
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}
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new_versionlink = get_versionlink(parent_path, new_log_seq, new_host, &new_versionlink_path);
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if (unlikely(!new_versionlink)) {
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MARS_INF("new versionlink '%s' does not yet exist, we must wait for it.\n", SAFE_STR(new_versionlink_path));
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goto done;
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}
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status = -ENOMEM;
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other_version = path_make("%s/version-%09d-%s", parent_path, sequence, from_host);
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if (!other_version) {
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MARS_WRN("out of memory");
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goto out;
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// check: are the versionlinks correct?
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if (unlikely(strcmp(own_versionlink, old_versionlink))) {
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MARS_INF("old logfile is not yet completeley transferred, own_versionlink '%s' -> '%s' != old_versionlink '%s' -> '%s'\n", own_versionlink_path, own_versionlink, old_versionlink_path, old_versionlink);
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goto done;
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}
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status = -ENOENT;
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other_version_link = mars_readlink(other_version);
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if (!other_version_link) {
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MARS_WRN("cannot find other version symlink '%s'\n", other_version);
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goto out;
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// check: did I fully apply my old logfile data?
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own_replaylink = get_replaylink(parent_path, my_id(), &own_replaylink_path);
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if (unlikely(!own_replaylink)) {
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MARS_ERR("cannot read my own replaylink '%s'\n", SAFE_STR(own_replaylink_path));
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goto done;
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}
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own_r_len = skip_part(own_replaylink);
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own_v_offset = skip_part(own_versionlink);
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if (unlikely(!own_versionlink[own_v_offset++])) {
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MARS_ERR("own version link '%s' -> '%s' is malformed\n", own_versionlink_path, own_versionlink);
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goto done;
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}
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own_v_len = skip_part(own_versionlink + own_v_offset);
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if (unlikely(own_r_len != own_v_len ||
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strncmp(own_replaylink, own_versionlink + own_v_offset, own_r_len))) {
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MARS_ERR("internal problem: logfile name mismatch between '%s' and '%s'\n", own_replaylink, own_versionlink);
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goto done;
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}
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if (unlikely(!own_replaylink[own_r_len])) {
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MARS_ERR("own replay link '%s' -> '%s' is malformed\n", own_replaylink_path, own_replaylink);
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goto done;
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}
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own_r_offset = own_r_len + 1;
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if (unlikely(!own_versionlink[own_v_len])) {
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MARS_ERR("own version link '%s' -> '%s' is malformed\n", own_versionlink_path, own_versionlink);
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goto done;
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}
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own_v_offset += own_r_len + 1;
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own_r_len = skip_part(own_replaylink + own_r_offset);
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own_v_len = skip_part(own_versionlink + own_v_offset);
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if (unlikely(own_r_len != own_v_len ||
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strncmp(own_replaylink + own_r_offset, own_versionlink + own_v_offset, own_r_len))) {
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MARS_INF("log replay is not yet finished: '%s' and '%s' are reporting different positions.\n", own_replaylink, own_versionlink);
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goto done;
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}
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if (!strcmp(my_version_link, other_version_link)) {
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MARS_DBG("VERSION OK '%s'\n", my_version_link);
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status = 1;
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} else {
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MARS_WRN("VERSION MISMATCH '%s' != '%s' => check for SPLIT BRAIN!\n", my_version_link, other_version_link);
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status = 0;
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// last check: is the new versionlink based on the old one?
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len1 = skip_sect(own_versionlink);
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offs2 = skip_sect(new_versionlink) + 1;
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len2 = skip_sect(new_versionlink + offs2);
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if (unlikely(len1 != len2 ||
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strncmp(own_versionlink, new_versionlink + offs2, len1))) {
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MARS_WRN("VERSION MISMATCH old '%s' -> '%s' new '%s' -> '%s' ==(%d,%d) ===> check for SPLIT BRAIN!\n", own_versionlink_path, own_versionlink, new_versionlink_path, new_versionlink, len1, len2);
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goto done;
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}
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out:
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brick_string_free(my_version);
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brick_string_free(my_version_link);
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brick_string_free(other_version);
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brick_string_free(other_version_link);
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brick_string_free(from_host);
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return status;
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// report success
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res = true;
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MARS_DBG("VERSION OK '%s' -> '%s'\n", own_versionlink_path, own_versionlink);
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done:
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brick_string_free(old_host);
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brick_string_free(new_host);
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brick_string_free(own_versionlink_path);
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brick_string_free(old_versionlink_path);
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brick_string_free(new_versionlink_path);
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brick_string_free(own_versionlink);
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brick_string_free(old_versionlink);
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brick_string_free(new_versionlink);
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brick_string_free(own_replaylink_path);
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brick_string_free(own_replaylink);
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return res;
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}
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static
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@ -2035,17 +2126,11 @@ int _make_logging_status(struct mars_rotate *rot)
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*/
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if (!trans_brick->power.button && !trans_brick->power.led_on && trans_brick->power.led_off) {
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if (rot->next_relevant_log) {
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MARS_DBG("check switchover from '%s' to '%s' (size = %lld, next_next = %p, allow_replay = %d)\n", dent->d_path, rot->next_relevant_log->d_path, rot->next_relevant_log->new_stat.size, rot->next_next_relevant_log, rot->allow_replay);
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if ((rot->next_relevant_log->new_stat.size > 0 || rot->next_next_relevant_log || (long long)jiffies > rot->switchover_timeout + 30 * HZ) &&
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rot->allow_replay &&
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_check_versionlink(global, parent->d_path, dent->d_serial, end_pos) > 0) {
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rot->switchover_timeout = 0;
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MARS_DBG("check switchover from '%s' to '%s' (size = %lld, next_next = %p)\n", dent->d_path, rot->next_relevant_log->d_path, rot->next_relevant_log->new_stat.size, rot->next_next_relevant_log);
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if (rot->allow_replay &&
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is_switchover_possible(parent->d_path, dent->d_path, rot->next_relevant_log->d_path)) {
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MARS_DBG("switching over from '%s' to next relevant transaction log '%s'\n", dent->d_path, rot->next_relevant_log->d_path);
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_make_new_replaylink(rot, rot->next_relevant_log->d_rest, rot->next_relevant_log->d_serial, rot->next_relevant_log->new_stat.size);
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} else {
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MARS_DBG("waiting for logfile to become stable\n");
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if (!rot->switchover_timeout)
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rot->switchover_timeout = jiffies;
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}
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} else if (rot->todo_primary) {
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MARS_DBG("preparing new transaction log '%s' from version %d to %d\n", dent->d_path, dent->d_serial, dent->d_serial + 1);
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