[FS-1111] Counts dir entries in a dir before writing to it.

pantheon-systems · Feb 13, 2023 · 934aa78 · 934aa78
1 parent 23fb283
commit 934aa78
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diff --git a/src/fusedav.c b/src/fusedav.c
@@ -1376,6 +1376,9 @@ static int dav_mkdir(const char *path, mode_t mode) {
     long response_code = 500; // seed it as bad so we can enter the loop
     CURLcode res = CURLE_OK;
     rwp_t rwp = WRITE;
+    char *parentpath;
+    unsigned BLOCKING_THRESHOLD = 5;
+    unsigned direntcnt;
 
     if (use_readonly_mode()) {
         log_print(LOG_WARNING, SECTION_FUSEDAV_FILE, "dav_mkdir: %s aborted; in readonly mode", path);
@@ -1387,6 +1390,25 @@ static int dav_mkdir(const char *path, mode_t mode) {
 
     log_print(LOG_INFO, SECTION_FUSEDAV_DIR, "CALLBACK: %s(%s, %04o)", funcname, path, mode);
 
+    // Highly populated directory check
+    parentpath = path_parent(path);
+    if (parentpath == NULL) {
+        log_print(LOG_NOTICE, SECTION_FUSEDAV_DIR, "Stat entry for the path %s is NULL.", path);
+    } else {
+        direntcnt = log_dirent_count(config->cache, parentpath);
+        if(direntcnt > BLOCKING_THRESHOLD) {
+            log_print(LOG_NOTICE, SECTION_FUSEDAV_DIR, "dav_mkdir: %s; dirent count (%u) above threshold for %s", path, direntcnt, parentpath);
+            // TODO: This is currently just logging but not preventing the dav_mkdir operation.
+            // Once we are confident on the decision to go ahead with blocking the writes,
+            // uncomment/modify the code below to enforce it. Specific error to client TBD, ENOSPC used tentatively.
+
+            // log_print(LOG_WARNING, SECTION_FUSEDAV_DIR, "dav_mkdir: %s aborted; dirent count (%u) above threshold for %s", path, direntcnt, parentpath);
+            // g_set_error(&gerr, fusedav_quark(), ENOSPC, "aborted; dirent count above threshold");
+            // return processed_gerror("dav_mkdir: ", path, &gerr);
+        }
+    }
+    free(parentpath);
+
     snprintf(fn, sizeof(fn), "%s/", path);
 
     for (int idx = 0; idx < num_filesystem_server_nodes && (res != CURLE_OK || response_code >= 500); idx++) {
@@ -2129,6 +2151,9 @@ static int dav_create(const char *path, mode_t mode, struct fuse_file_info *info
     struct stat_cache_value value;
     GError *gerr = NULL;
     int fd;
+    char *parentpath;
+    unsigned BLOCKING_THRESHOLD = 5;
+    unsigned direntcnt;
 
     if (use_readonly_mode()) {
         log_print(LOG_WARNING, SECTION_FUSEDAV_FILE, "dav_create: %s aborted; in readonly mode", path);
@@ -2140,6 +2165,25 @@ static int dav_create(const char *path, mode_t mode, struct fuse_file_info *info
 
     log_print(LOG_INFO, SECTION_FUSEDAV_FILE, "CALLBACK: dav_create(%s, %04o)", path, mode);
 
+    // Highly populated directory check
+    parentpath = path_parent(path);
+    if (parentpath == NULL) {
+        log_print(LOG_NOTICE, SECTION_FUSEDAV_FILE, "Stat entry for the path %s is NULL.", path);
+    } else {
+        direntcnt = log_dirent_count(config->cache, parentpath);
+        if(direntcnt > BLOCKING_THRESHOLD) {
+            log_print(LOG_NOTICE, SECTION_FUSEDAV_FILE, "dav_create: %s; dirent count (%u) above threshold for %s", path, direntcnt, parentpath);
+            // TODO: This is currently just logging but not preventing the dav_create operation.
+            // Once we are confident on the decision to go ahead with blocking the writes,
+            // uncomment/modify the code below to enforce it. Specific error to client TBD, ENOSPC used tentatively.
+
+            // log_print(LOG_WARNING, SECTION_FUSEDAV_FILE, "dav_create: %s aborted; dirent count (%u) above threshold for %s", path, direntcnt, parentpath);
+            // g_set_error(&gerr, fusedav_quark(), ENOSPC, "aborted; dirent count above threshold");
+            // return processed_gerror("dav_create: ", path, &gerr);
+        }
+    }
+    free(parentpath);
+
     info->flags |= O_CREAT | O_TRUNC;
     do_open(path, info, &gerr);
 

diff --git a/src/statcache.c b/src/statcache.c
@@ -931,6 +931,58 @@ int stat_cache_enumerate(stat_cache_t *cache, const char *path_prefix, void (*f)
     return E_SC_SUCCESS;
 }
 
+// log_dirent_count is based on stat_cache_enumerate and ignores cache freshness.
+unsigned log_dirent_count(stat_cache_t *cache, const char *path_prefix) {
+    struct stat_cache_iterator *iter;
+    struct stat_cache_entry *entry;
+    unsigned found_entries = 0;
+
+    // BUMP(statcache_enumerate);
+
+    // log_print(LOG_DEBUG, SECTION_STATCACHE_ITER, "count_dir_entries(%s)", path_prefix);
+
+    //stat_cache_list_all(cache, path_prefix);
+    // if (!force) {
+    //     time_t timestamp;
+    //     time_t current_time;
+    //     // Pass NULL for gerr; not tracking error, just zero return
+    //     timestamp = stat_cache_read_updated_children(cache, path_prefix, NULL);
+
+    //     if (timestamp == 0) {
+    //         return -STAT_CACHE_NO_DATA;
+    //     }
+
+    //     // Check for cache values which are too old; but timestamp = 0 needs to trigger below
+    //     current_time = time(NULL);
+    //     if (current_time - timestamp > STAT_CACHE_NEGATIVE_TTL) {
+    //         log_print(LOG_DEBUG, SECTION_STATCACHE_ITER, "cache value too old: %s %u", path_prefix, (unsigned)timestamp);
+    //         return -STAT_CACHE_OLD_DATA;
+    //     }
+    // }
+
+    iter = stat_cache_iter_init(cache, path_prefix);
+    log_print(LOG_NOTICE, SECTION_STATCACHE_ITER, "iterator initialized with prefix: %s", iter->key_prefix);
+
+    while ((entry = stat_cache_iter_current(iter))) {
+        // log_print(LOG_NOTICE, SECTION_STATCACHE_ITER, "key: %s", entry->key);
+        // log_print(LOG_NOTICE, SECTION_STATCACHE_ITER, "fn: %s", entry->key + (iter->key_prefix_len - 1));
+        // Ignore negative (non-existent) entries, those tagged with st_mode == 0
+        if (entry->value->st.st_mode != 0) {
+            // f(path_prefix, entry->key + (iter->key_prefix_len - 1), user);
+            ++found_entries;
+        }
+        free(entry);
+        stat_cache_iter_next(iter);
+    }
+    stat_cache_iterator_free(iter);
+    log_print(LOG_NOTICE, SECTION_STATCACHE_ITER, "Done iterating: %u items.", found_entries);
+
+    // if (found_entries == 0)
+    //     return -STAT_CACHE_NO_DATA;
+
+    return found_entries;
+}
+
 void stat_cache_walk(void) {
     leveldb_readoptions_t *roptions;
     struct leveldb_iterator_t *iter;

diff --git a/src/statcache.h b/src/statcache.h
@@ -87,6 +87,7 @@ void stat_cache_delete_older(stat_cache_t *cache, const char *key_prefix, unsign
 void stat_cache_walk(void);
 int stat_cache_enumerate(stat_cache_t *cache, const char *key_prefix, void (*f) (const char *path_prefix, 
             const char *filename, void *user), void *user, bool force);
+unsigned log_dirent_count(stat_cache_t *cache, const char *key_prefix);
 bool stat_cache_dir_has_child(stat_cache_t *cache, const char *path);
 void stat_cache_prune(stat_cache_t *cache, bool first);