From 8a17cd810fa6cbe7b11139ff0f6f24e7bacd318b Mon Sep 17 00:00:00 2001 From: Volker Lendecke Date: Mon, 13 Jul 2009 17:04:29 +0200 Subject: Make gencache more stable This provides a compromise between stability and performance: gencache is a persistent database these days that for performance reasons can not use tdb transactions for all writes. This patch splits up gencache into gencache.tdb and gencache_notrans.tdb. gencache_notrans is used with CLEAR_IF_FIRST, writes to it don't use transactions. By default every 5 minutes and when a program exits, all entries from _notrans.tdb are transferred to gencache.tdb in one transaction. --- source3/include/proto.h | 1 + source3/lib/gencache.c | 283 +++++++++++++++++++++++++++++++++++++++++--- source3/nmbd/nmbd.c | 2 + source3/smbd/server.c | 1 + source3/utils/net.c | 2 + source3/utils/net_cache.c | 23 ++++ source3/winbindd/winbindd.c | 2 + 7 files changed, 299 insertions(+), 15 deletions(-) diff --git a/source3/include/proto.h b/source3/include/proto.h index 23bd22aadc..dd49e53338 100644 --- a/source3/include/proto.h +++ b/source3/include/proto.h @@ -519,6 +519,7 @@ bool gencache_set(const char *keystr, const char *value, time_t timeout); bool gencache_del(const char *keystr); bool gencache_get(const char *keystr, char **valstr, time_t *timeout); bool gencache_get_data_blob(const char *keystr, DATA_BLOB *blob, bool *expired); +bool gencache_stabilize(void); bool gencache_set_data_blob(const char *keystr, const DATA_BLOB *blob, time_t timeout); void gencache_iterate(void (*fn)(const char* key, const char *value, time_t timeout, void* dptr), void* data, const char* keystr_pattern); diff --git a/source3/lib/gencache.c b/source3/lib/gencache.c index 06eb29345b..73f433c1c0 100644 --- a/source3/lib/gencache.c +++ b/source3/lib/gencache.c @@ -32,6 +32,7 @@ #define BLOB_TYPE_LEN 9 static struct tdb_context *cache; +static struct tdb_context *cache_notrans; /** * @file gencache.c @@ -52,6 +53,7 @@ static struct tdb_context *cache; static bool gencache_init(void) { char* cache_fname = NULL; + int open_flags = O_RDWR|O_CREAT; /* skip file open if it's already opened */ if (cache) return True; @@ -60,11 +62,12 @@ static bool gencache_init(void) DEBUG(5, ("Opening cache file at %s\n", cache_fname)); - cache = tdb_open_log(cache_fname, 0, TDB_DEFAULT, - O_RDWR|O_CREAT, 0644); + cache = tdb_open_log(cache_fname, 0, TDB_DEFAULT, open_flags, 0644); if (!cache && (errno == EACCES)) { - cache = tdb_open_log(cache_fname, 0, TDB_DEFAULT, O_RDONLY, 0644); + open_flags = O_RDONLY; + cache = tdb_open_log(cache_fname, 0, TDB_DEFAULT, open_flags, + 0644); if (cache) { DEBUG(5, ("gencache_init: Opening cache file %s read-only.\n", cache_fname)); } @@ -74,9 +77,30 @@ static bool gencache_init(void) DEBUG(5, ("Attempt to open gencache.tdb has failed.\n")); return False; } + + cache_fname = lock_path("gencache_notrans.tdb"); + + DEBUG(5, ("Opening cache file at %s\n", cache_fname)); + + cache_notrans = tdb_open_log(cache_fname, 0, TDB_CLEAR_IF_FIRST, + open_flags, 0644); + if (cache_notrans == NULL) { + DEBUG(5, ("Opening %s failed: %s\n", cache_fname, + strerror(errno))); + tdb_close(cache); + return false; + } + return True; } +static TDB_DATA last_stabilize_key(void) +{ + TDB_DATA result; + result.dptr = (uint8_t *)"@LAST_STABILIZED"; + result.dsize = 17; + return result; +} /** * Set an entry in the cache file. If there's no such @@ -95,6 +119,13 @@ bool gencache_set(const char *keystr, const char *value, time_t timeout) int ret; TDB_DATA databuf; char* valstr = NULL; + time_t last_stabilize; + + if (tdb_data_cmp(string_term_tdb_data(keystr), + last_stabilize_key()) == 0) { + DEBUG(10, ("Can't store %s as a key\n", keystr)); + return false; + } if ((keystr == NULL) || (value == NULL)) { return false; @@ -112,9 +143,31 @@ bool gencache_set(const char *keystr, const char *value, time_t timeout) (int)(timeout - time(NULL)), timeout > time(NULL) ? "ahead" : "in the past")); - ret = tdb_store_bystring(cache, keystr, databuf, 0); + ret = tdb_store_bystring(cache_notrans, keystr, databuf, 0); SAFE_FREE(valstr); + if (ret != 0) { + return false; + } + + /* + * Every 5 minutes, call gencache_stabilize() to not let grow + * gencache_notrans.tdb too large. + */ + + last_stabilize = 0; + databuf = tdb_fetch(cache_notrans, last_stabilize_key()); + if ((databuf.dptr != NULL) + && (databuf.dptr[databuf.dsize-1] == '\0')) { + last_stabilize = atoi((char *)databuf.dptr); + SAFE_FREE(databuf.dptr); + } + if ((last_stabilize + + lp_parm_int(-1, "gencache", "stabilize_interval", 300)) + < time(NULL)) { + gencache_stabilize(); + } + return ret == 0; } @@ -129,7 +182,9 @@ bool gencache_set(const char *keystr, const char *value, time_t timeout) bool gencache_del(const char *keystr) { - int ret; + bool exists; + bool ret = false; + char *value; if (keystr == NULL) { return false; @@ -138,11 +193,46 @@ bool gencache_del(const char *keystr) if (!gencache_init()) return False; DEBUG(10, ("Deleting cache entry (key = %s)\n", keystr)); - ret = tdb_delete_bystring(cache, keystr); - return ret == 0; + if (tdb_lock_bystring(cache_notrans, keystr) == -1) { + DEBUG(5, ("Could not lock key for %s\n", keystr)); + return false; + } + + /* + * We delete an element by setting its timeout to 0. This way we don't + * have to do a transaction on gencache.tdb every time we delete an + * element. + */ + + exists = gencache_get(keystr, &value, NULL); + if (exists) { + SAFE_FREE(value); + ret = gencache_set(keystr, "", 0); + } + tdb_unlock_bystring(cache_notrans, keystr); + return ret; } +static bool gencache_pull_timeout(char *val, time_t *pres, char **pendptr) +{ + time_t res; + char *endptr; + + res = strtol(val, &endptr, 10); + + if ((endptr == NULL) || (*endptr != '/')) { + DEBUG(2, ("Invalid gencache data format: %s\n", val)); + return false; + } + if (pres != NULL) { + *pres = res; + } + if (pendptr != NULL) { + *pendptr = endptr; + } + return true; +} /** * Get existing entry from the cache file. @@ -167,22 +257,29 @@ bool gencache_get(const char *keystr, char **valstr, time_t *timeout) return false; } + if (tdb_data_cmp(string_term_tdb_data(keystr), + last_stabilize_key()) == 0) { + DEBUG(10, ("Can't get %s as a key\n", keystr)); + return false; + } + if (!gencache_init()) { return False; } - databuf = tdb_fetch_bystring(cache, keystr); + databuf = tdb_fetch_bystring(cache_notrans, keystr); if (databuf.dptr == NULL) { - DEBUG(10, ("Cache entry with key = %s couldn't be found\n", + databuf = tdb_fetch_bystring(cache, keystr); + } + + if (databuf.dptr == NULL) { + DEBUG(10, ("Cache entry with key = %s couldn't be found \n", keystr)); return False; } - t = strtol((const char *)databuf.dptr, &endptr, 10); - - if ((endptr == NULL) || (*endptr != '/')) { - DEBUG(2, ("Invalid gencache data format: %s\n", databuf.dptr)); + if (!gencache_pull_timeout((char *)databuf.dptr, &t, &endptr)) { SAFE_FREE(databuf.dptr); return False; } @@ -191,10 +288,21 @@ bool gencache_get(const char *keystr, char **valstr, time_t *timeout) "timeout = %s", t > time(NULL) ? "valid" : "expired", keystr, endptr+1, ctime(&t))); + if (t == 0) { + /* Deleted */ + SAFE_FREE(databuf.dptr); + return False; + } + if (t <= time(NULL)) { - /* We're expired, delete the entry */ - tdb_delete_bystring(cache, keystr); + /* + * We're expired, delete the entry. We can't use gencache_del + * here, because that uses gencache_get_data_blob for checking + * the existence of a record. We know the thing exists and + * directly store an empty value with 0 timeout. + */ + gencache_set(keystr, "", 0); SAFE_FREE(databuf.dptr); return False; @@ -218,6 +326,137 @@ bool gencache_get(const char *keystr, char **valstr, time_t *timeout) return True; } +struct stabilize_state { + bool written; + bool error; +}; +static int stabilize_fn(struct tdb_context *tdb, TDB_DATA key, TDB_DATA val, + void *priv); + +/** + * Stabilize gencache + * + * Migrate the clear-if-first gencache data to the stable, + * transaction-based gencache.tdb + */ + +bool gencache_stabilize(void) +{ + struct stabilize_state state; + int res; + char *now; + + if (!gencache_init()) { + return false; + } + + res = tdb_transaction_start(cache); + if (res == -1) { + DEBUG(10, ("Could not start transaction on gencache.tdb: " + "%s\n", tdb_errorstr(cache))); + return false; + } + res = tdb_transaction_start(cache_notrans); + if (res == -1) { + tdb_transaction_cancel(cache); + DEBUG(10, ("Could not start transaction on " + "gencache_notrans.tdb: %s\n", + tdb_errorstr(cache_notrans))); + return false; + } + + state.error = false; + state.written = false; + + res = tdb_traverse(cache_notrans, stabilize_fn, &state); + if ((res == -1) || state.error) { + if ((tdb_transaction_cancel(cache_notrans) == -1) + || (tdb_transaction_cancel(cache) == -1)) { + smb_panic("tdb_transaction_cancel failed\n"); + } + return false; + } + + if (!state.written) { + if ((tdb_transaction_cancel(cache_notrans) == -1) + || (tdb_transaction_cancel(cache) == -1)) { + smb_panic("tdb_transaction_cancel failed\n"); + } + return true; + } + + res = tdb_transaction_commit(cache); + if (res == -1) { + DEBUG(10, ("tdb_transaction_commit on gencache.tdb failed: " + "%s\n", tdb_errorstr(cache))); + if (tdb_transaction_cancel(cache_notrans) == -1) { + smb_panic("tdb_transaction_cancel failed\n"); + } + return false; + } + + res = tdb_transaction_commit(cache_notrans); + if (res == -1) { + DEBUG(10, ("tdb_transaction_commit on gencache.tdb failed: " + "%s\n", tdb_errorstr(cache))); + return false; + } + + now = talloc_asprintf(talloc_tos(), "%d", (int)time(NULL)); + if (now != NULL) { + tdb_store(cache_notrans, last_stabilize_key(), + string_term_tdb_data(now), 0); + TALLOC_FREE(now); + } + + return true; +} + +static int stabilize_fn(struct tdb_context *tdb, TDB_DATA key, TDB_DATA val, + void *priv) +{ + struct stabilize_state *state = (struct stabilize_state *)priv; + int res; + time_t timeout; + + if (tdb_data_cmp(key, last_stabilize_key()) == 0) { + return 0; + } + + if (!gencache_pull_timeout((char *)val.dptr, &timeout, NULL)) { + DEBUG(10, ("Ignoring invalid entry\n")); + return 0; + } + if ((timeout < time(NULL)) || (val.dsize == 0)) { + res = tdb_delete(cache, key); + if ((res == -1) && (tdb_error(cache) == TDB_ERR_NOEXIST)) { + res = 0; + } else { + state->written = true; + } + } else { + res = tdb_store(cache, key, val, 0); + if (res == 0) { + state->written = true; + } + } + + if (res == -1) { + DEBUG(10, ("Transfer to gencache.tdb failed: %s\n", + tdb_errorstr(cache))); + state->error = true; + return -1; + } + + if (tdb_delete(cache_notrans, key) == -1) { + DEBUG(10, ("tdb_delete from gencache_notrans.tdb failed: " + "%s\n", tdb_errorstr(cache_notrans))); + state->error = true; + return -1; + } + return 0; +} + /** * Get existing entry from the cache file. * @@ -387,6 +626,7 @@ struct gencache_iterate_state { void *priv); const char *pattern; void *priv; + bool in_persistent; }; static int gencache_iterate_fn(struct tdb_context *tdb, TDB_DATA key, @@ -402,6 +642,14 @@ static int gencache_iterate_fn(struct tdb_context *tdb, TDB_DATA key, time_t timeout; char *timeout_endp; + if (tdb_data_cmp(key, last_stabilize_key()) == 0) { + return 0; + } + + if (state->in_persistent && tdb_exists(cache_notrans, key)) { + return 0; + } + if (key.dptr[key.dsize-1] == '\0') { keystr = (char *)key.dptr; } else { @@ -462,5 +710,10 @@ void gencache_iterate(void (*fn)(const char* key, const char *value, time_t time state.fn = fn; state.pattern = keystr_pattern; state.priv = data; + + state.in_persistent = false; + tdb_traverse(cache_notrans, gencache_iterate_fn, &state); + + state.in_persistent = true; tdb_traverse(cache, gencache_iterate_fn, &state); } diff --git a/source3/nmbd/nmbd.c b/source3/nmbd/nmbd.c index 848baeff3d..961e930728 100644 --- a/source3/nmbd/nmbd.c +++ b/source3/nmbd/nmbd.c @@ -82,6 +82,8 @@ static void terminate(void) /* If there was an async dns child - kill it. */ kill_async_dns_child(); + gencache_stabilize(); + pidfile_unlink(); exit(0); diff --git a/source3/smbd/server.c b/source3/smbd/server.c index 6951fac171..a1dec0327c 100644 --- a/source3/smbd/server.c +++ b/source3/smbd/server.c @@ -868,6 +868,7 @@ static void exit_server_common(enum server_exit_reason how, if (am_parent) { pidfile_unlink(); } + gencache_stabilize(); } /* if we had any open SMB connections when we exited then we diff --git a/source3/utils/net.c b/source3/utils/net.c index 0e3946f5a5..9f29ac42fe 100644 --- a/source3/utils/net.c +++ b/source3/utils/net.c @@ -762,6 +762,8 @@ static struct functable net_func[] = { DEBUG(2,("return code = %d\n", rc)); + gencache_stabilize(); + libnetapi_free(c->netapi_ctx); poptFreeContext(pc); diff --git a/source3/utils/net_cache.c b/source3/utils/net_cache.c index 74d8d29b4b..36cd12fb82 100644 --- a/source3/utils/net_cache.c +++ b/source3/utils/net_cache.c @@ -297,6 +297,21 @@ static int net_cache_flush(struct net_context *c, int argc, const char **argv) return 0; } +static int net_cache_stabilize(struct net_context *c, int argc, + const char **argv) +{ + if (c->display_usage) { + d_printf("Usage:\n" + "net cache flush\n" + " Delete all cache entries.\n"); + return 0; + } + + if (!gencache_stabilize()) { + return -1; + } + return 0; +} /** * Entry point to 'net cache' subfunctionality * @@ -362,6 +377,14 @@ int net_cache(struct net_context *c, int argc, const char **argv) "net cache flush\n" " Delete all cache entries" }, + { + "stabilize", + net_cache_stabilize, + NET_TRANSPORT_LOCAL, + "Move transient cache content to stable storage", + "net cache stabilize\n" + " Move transient cache content to stable storage" + }, {NULL, NULL, 0, NULL, NULL} }; diff --git a/source3/winbindd/winbindd.c b/source3/winbindd/winbindd.c index d617fe1f0b..34eaeb2d79 100644 --- a/source3/winbindd/winbindd.c +++ b/source3/winbindd/winbindd.c @@ -163,6 +163,8 @@ static void terminate(bool is_parent) trustdom_cache_shutdown(); + gencache_stabilize(); + #if 0 if (interactive) { TALLOC_CTX *mem_ctx = talloc_init("end_description"); -- cgit