several fixes:

*) do not add event if file was used less than min_uses
*) do not rely upon event to avoid race conditions
*) ngx_open_file_lookup()
This commit is contained in:
Igor Sysoev 2007-12-25 10:46:40 +00:00
parent d02661a96b
commit 421a3b800f
2 changed files with 272 additions and 197 deletions

View File

@ -18,15 +18,21 @@
static void ngx_open_file_cache_cleanup(void *data);
static ngx_int_t ngx_open_and_stat_file(u_char *name, ngx_open_file_info_t *of,
ngx_log_t *log);
static void ngx_open_file_add_event(ngx_open_file_cache_t *cache,
ngx_cached_open_file_t *file, ngx_open_file_info_t *of, ngx_log_t *log);
static void ngx_open_file_cleanup(void *data);
static void ngx_close_cached_file(ngx_open_file_cache_t *cache,
ngx_cached_open_file_t *file, ngx_uint_t min_uses, ngx_log_t *log);
static ngx_int_t ngx_open_and_stat_file(u_char *name, ngx_open_file_info_t *of,
ngx_log_t *log);
static void ngx_open_file_del_event(ngx_cached_open_file_t *file);
static void ngx_expire_old_cached_files(ngx_open_file_cache_t *cache,
ngx_uint_t n, ngx_log_t *log);
static void ngx_open_file_cache_rbtree_insert_value(ngx_rbtree_node_t *temp,
ngx_rbtree_node_t *node, ngx_rbtree_node_t *sentinel);
static ngx_cached_open_file_t *
ngx_open_file_lookup(ngx_open_file_cache_t *cache, ngx_str_t *name,
uint32_t hash);
static void ngx_open_file_cache_remove(ngx_event_t *ev);
@ -124,11 +130,9 @@ ngx_open_cached_file(ngx_open_file_cache_t *cache, ngx_str_t *name,
time_t now;
uint32_t hash;
ngx_int_t rc;
ngx_rbtree_node_t *node, *sentinel;
ngx_pool_cleanup_t *cln;
ngx_cached_open_file_t *file;
ngx_pool_cleanup_file_t *clnf;
ngx_open_file_cache_event_t *fev;
ngx_open_file_cache_cleanup_t *ofcln;
of->err = 0;
@ -159,163 +163,147 @@ ngx_open_cached_file(ngx_open_file_cache_t *cache, ngx_str_t *name,
return NGX_ERROR;
}
hash = ngx_crc32_long(name->data, name->len);
node = cache->rbtree.root;
sentinel = cache->rbtree.sentinel;
now = ngx_time();
while (node != sentinel) {
hash = ngx_crc32_long(name->data, name->len);
if (hash < node->key) {
node = node->left;
continue;
}
file = ngx_open_file_lookup(cache, name, hash);
if (hash > node->key) {
node = node->right;
continue;
}
if (file) {
/* hash == node->key */
file->uses++;
do {
file = (ngx_cached_open_file_t *) node;
ngx_queue_remove(&file->queue);
rc = ngx_strcmp(name->data, file->name);
if (file->fd == NGX_INVALID_FILE && file->err == 0 && !file->is_dir) {
if (rc == 0) {
/* file was not used often enough to keep open */
file->uses++;
rc = ngx_open_and_stat_file(name->data, of, pool->log);
ngx_queue_remove(&file->queue);
if (file->fd == NGX_INVALID_FILE
&& file->err == 0
&& !file->is_dir)
{
/* file was not used often enough to be open */
rc = ngx_open_and_stat_file(name->data, of, pool->log);
if (rc != NGX_OK && (of->err == 0 || !of->errors)) {
goto failed;
}
goto update;
}
if (file->event || now - file->created < of->valid) {
if (file->err == 0) {
of->fd = file->fd;
of->uniq = file->uniq;
of->mtime = file->mtime;
of->size = file->size;
of->is_dir = file->is_dir;
of->is_file = file->is_file;
of->is_link = file->is_link;
of->is_exec = file->is_exec;
if (!file->is_dir) {
file->count++;
}
} else {
of->err = file->err;
}
goto found;
}
ngx_log_debug4(NGX_LOG_DEBUG_CORE, pool->log, 0,
"retest open file: %s, fd:%d, c:%d, e:%d",
file->name, file->fd, file->count, file->err);
if (file->is_dir) {
/*
* chances that directory became file are very small
* so test_dir flag allows to use a single ngx_file_info()
* syscall instead of three syscalls
*/
of->test_dir = 1;
}
rc = ngx_open_and_stat_file(name->data, of, pool->log);
if (rc != NGX_OK && (of->err == 0 || !of->errors)) {
goto failed;
}
if (of->is_dir) {
if (file->is_dir || file->err) {
goto update;
}
/* file became directory */
} else if (of->err == 0) { /* file */
if (file->is_dir || file->err) {
goto update;
}
if (of->uniq == file->uniq
&& of->mtime == file->mtime
&& of->size == file->size)
{
if (ngx_close_file(of->fd) == NGX_FILE_ERROR) {
ngx_log_error(NGX_LOG_ALERT, pool->log, ngx_errno,
ngx_close_file_n " \"%s\" failed",
name->data);
}
of->fd = file->fd;
file->count++;
goto renew;
}
/* file was changed */
} else { /* error to cache */
if (file->err || file->is_dir) {
goto update;
}
/* file was removed, etc. */
}
if (file->count == 0) {
if (ngx_close_file(file->fd) == NGX_FILE_ERROR) {
ngx_log_error(NGX_LOG_ALERT, pool->log, ngx_errno,
ngx_close_file_n " \"%s\" failed",
name->data);
}
goto update;
}
ngx_rbtree_delete(&cache->rbtree, &file->node);
cache->current--;
file->close = 1;
goto create;
if (rc != NGX_OK && (of->err == 0 || !of->errors)) {
goto failed;
}
node = (rc < 0) ? node->left : node->right;
goto add_event;
}
} while (node != sentinel && hash == node->key);
if ((file->event && file->use_event)
|| (file->event == NULL && now - file->created < of->valid))
{
if (file->err == 0) {
break;
of->fd = file->fd;
of->uniq = file->uniq;
of->mtime = file->mtime;
of->size = file->size;
of->is_dir = file->is_dir;
of->is_file = file->is_file;
of->is_link = file->is_link;
of->is_exec = file->is_exec;
if (!file->is_dir) {
file->count++;
ngx_open_file_add_event(cache, file, of, pool->log);
}
} else {
of->err = file->err;
}
goto found;
}
ngx_log_debug4(NGX_LOG_DEBUG_CORE, pool->log, 0,
"retest open file: %s, fd:%d, c:%d, e:%d",
file->name, file->fd, file->count, file->err);
if (file->is_dir) {
/*
* chances that directory became file are very small
* so test_dir flag allows to use a single syscall
* in ngx_file_info() instead of three syscalls
*/
of->test_dir = 1;
}
rc = ngx_open_and_stat_file(name->data, of, pool->log);
if (rc != NGX_OK && (of->err == 0 || !of->errors)) {
goto failed;
}
if (of->is_dir) {
if (file->is_dir || file->err) {
goto update;
}
/* file became directory */
} else if (of->err == 0) { /* file */
if (file->is_dir || file->err) {
goto add_event;
}
if (of->uniq == file->uniq
&& of->mtime == file->mtime
&& of->size == file->size)
{
if (ngx_close_file(of->fd) == NGX_FILE_ERROR) {
ngx_log_error(NGX_LOG_ALERT, pool->log, ngx_errno,
ngx_close_file_n " \"%s\" failed",
name->data);
}
of->fd = file->fd;
file->count++;
if (file->event) {
file->use_event = 1;
goto renew;
}
ngx_open_file_add_event(cache, file, of, pool->log);
goto renew;
}
/* file was changed */
} else { /* error to cache */
if (file->err || file->is_dir) {
goto update;
}
/* file was removed, etc. */
}
if (file->count == 0) {
ngx_open_file_del_event(file);
if (ngx_close_file(file->fd) == NGX_FILE_ERROR) {
ngx_log_error(NGX_LOG_ALERT, pool->log, ngx_errno,
ngx_close_file_n " \"%s\" failed",
name->data);
}
goto add_event;
}
ngx_rbtree_delete(&cache->rbtree, &file->node);
cache->current--;
file->close = 1;
goto create;
}
/* not found */
@ -356,52 +344,17 @@ create:
cache->current++;
file->count = 0;
file->uses = 1;
file->count = 0;
file->use_event = 0;
file->event = NULL;
add_event:
ngx_open_file_add_event(cache, file, of, pool->log);
update:
if (of->events
&& (ngx_event_flags & NGX_USE_VNODE_EVENT)
&& of->fd != NGX_INVALID_FILE)
{
file->event = ngx_calloc(sizeof(ngx_event_t), pool->log);
if (file->event== NULL) {
goto failed;
}
fev = ngx_alloc(sizeof(ngx_open_file_cache_event_t), pool->log);
if (fev == NULL) {
goto failed;
}
fev->fd = of->fd;
fev->file = file;
fev->cache = cache;
file->event->handler = ngx_open_file_cache_remove;
file->event->data = fev;
/*
* although vnode event may be called while ngx_cycle->poll
* destruction; however, cleanup procedures are run before any
* memory freeing and events will be canceled.
*/
file->event->log = ngx_cycle->log;
if (ngx_add_event(file->event, NGX_VNODE_EVENT, NGX_ONESHOT_EVENT)
!= NGX_OK)
{
ngx_free(file->event->data);
ngx_free(file->event);
goto failed;
}
} else {
file->event = NULL;
}
file->fd = of->fd;
file->err = of->err;
@ -550,6 +503,72 @@ ngx_open_and_stat_file(u_char *name, ngx_open_file_info_t *of, ngx_log_t *log)
}
/*
* we ignore any possible event setting error and
* fallback to usual periodic file retests
*/
static void
ngx_open_file_add_event(ngx_open_file_cache_t *cache,
ngx_cached_open_file_t *file, ngx_open_file_info_t *of, ngx_log_t *log)
{
ngx_open_file_cache_event_t *fev;
if (!(ngx_event_flags & NGX_USE_VNODE_EVENT)
|| !of->events
|| file->event
|| of->fd == NGX_INVALID_FILE
|| file->uses < of->min_uses)
{
return;
}
file->event = ngx_calloc(sizeof(ngx_event_t), log);
if (file->event== NULL) {
return;
}
fev = ngx_alloc(sizeof(ngx_open_file_cache_event_t), log);
if (fev == NULL) {
ngx_free(file->event);
file->event = NULL;
return;
}
fev->fd = of->fd;
fev->file = file;
fev->cache = cache;
file->event->handler = ngx_open_file_cache_remove;
file->event->data = fev;
/*
* although vnode event may be called while ngx_cycle->poll
* destruction, however, cleanup procedures are run before any
* memory freeing and events will be canceled.
*/
file->event->log = ngx_cycle->log;
if (ngx_add_event(file->event, NGX_VNODE_EVENT, NGX_ONESHOT_EVENT)
!= NGX_OK)
{
ngx_free(file->event->data);
ngx_free(file->event);
file->event = NULL;
return;
}
/*
* we do not file->use_event here because there may be a race
* condition between opening file and adding event, so we rely
* upon event notification only after first file revalidation
*/
return;
}
static void
ngx_open_file_cleanup(void *data)
{
@ -585,14 +604,7 @@ ngx_close_cached_file(ngx_open_file_cache_t *cache,
}
}
if (file->event) {
(void) ngx_del_event(file->event, NGX_VNODE_EVENT,
file->count ? NGX_FLUSH_EVENT : NGX_CLOSE_EVENT);
ngx_free(file->event->data);
ngx_free(file->event);
file->event = NULL;
}
ngx_open_file_del_event(file);
if (file->count) {
return;
@ -617,6 +629,23 @@ ngx_close_cached_file(ngx_open_file_cache_t *cache,
}
static void
ngx_open_file_del_event(ngx_cached_open_file_t *file)
{
if (file->event == NULL) {
return;
}
(void) ngx_del_event(file->event, NGX_VNODE_EVENT,
file->count ? NGX_FLUSH_EVENT : NGX_CLOSE_EVENT);
ngx_free(file->event->data);
ngx_free(file->event);
file->event = NULL;
file->use_event = 0;
}
static void
ngx_expire_old_cached_files(ngx_open_file_cache_t *cache, ngx_uint_t n,
ngx_log_t *log)
@ -709,6 +738,51 @@ ngx_open_file_cache_rbtree_insert_value(ngx_rbtree_node_t *temp,
}
static ngx_cached_open_file_t *
ngx_open_file_lookup(ngx_open_file_cache_t *cache, ngx_str_t *name,
uint32_t hash)
{
ngx_int_t rc;
ngx_rbtree_node_t *node, *sentinel;
ngx_cached_open_file_t *file;
node = cache->rbtree.root;
sentinel = cache->rbtree.sentinel;
while (node != sentinel) {
if (hash < node->key) {
node = node->left;
continue;
}
if (hash > node->key) {
node = node->right;
continue;
}
/* hash == node->key */
do {
file = (ngx_cached_open_file_t *) node;
rc = ngx_strcmp(name->data, file->name);
if (rc == 0) {
return file;
}
node = (rc < 0) ? node->left : node->right;
} while (node != sentinel && hash == node->key);
break;
}
return NULL;
}
static void
ngx_open_file_cache_remove(ngx_event_t *ev)
{

View File

@ -54,6 +54,7 @@ struct ngx_cached_open_file_s {
unsigned count:24;
unsigned close:1;
unsigned use_event:1;
unsigned is_dir:1;
unsigned is_file:1;