From 974c1b398711b8782c01bbd3aec959a458296da8 Mon Sep 17 00:00:00 2001 From: Jeff Hostetler Date: Fri, 25 Mar 2022 18:02:44 +0000 Subject: fsmonitor: enhance existing comments, clarify trivial response handling Signed-off-by: Jeff Hostetler Signed-off-by: Junio C Hamano --- fsmonitor.c | 64 +++++++++++++++++++++++++++++++++++++++---------------------- 1 file changed, 41 insertions(+), 23 deletions(-) (limited to 'fsmonitor.c') diff --git a/fsmonitor.c b/fsmonitor.c index ab9bfc60b3..448d0ee33f 100644 --- a/fsmonitor.c +++ b/fsmonitor.c @@ -168,29 +168,15 @@ static int query_fsmonitor(int version, const char *last_update, struct strbuf * if (result) trace2_data_intmax("fsm_hook", NULL, "query/failed", result); - else { + else trace2_data_intmax("fsm_hook", NULL, "query/response-length", query_result->len); - if (fsmonitor_is_trivial_response(query_result)) - trace2_data_intmax("fsm_hook", NULL, - "query/trivial-response", 1); - } - trace2_region_leave("fsm_hook", "query", NULL); return result; } -int fsmonitor_is_trivial_response(const struct strbuf *query_result) -{ - static char trivial_response[3] = { '\0', '/', '\0' }; - - return query_result->len >= 3 && - !memcmp(trivial_response, - &query_result->buf[query_result->len - 3], 3); -} - static void fsmonitor_refresh_callback(struct index_state *istate, char *name) { int i, len = strlen(name); @@ -238,6 +224,7 @@ void refresh_fsmonitor(struct index_state *istate) struct strbuf last_update_token = STRBUF_INIT; char *buf; unsigned int i; + int is_trivial = 0; if (!core_fsmonitor || istate->fsmonitor_has_run_once) return; @@ -283,6 +270,7 @@ void refresh_fsmonitor(struct index_state *istate) query_success = 0; } else { bol = last_update_token.len + 1; + is_trivial = query_result.buf[bol] == '/'; } } else if (hook_version < 0) { hook_version = HOOK_INTERFACE_VERSION1; @@ -294,16 +282,38 @@ void refresh_fsmonitor(struct index_state *istate) if (hook_version == HOOK_INTERFACE_VERSION1) { query_success = !query_fsmonitor(HOOK_INTERFACE_VERSION1, istate->fsmonitor_last_update, &query_result); + if (query_success) + is_trivial = query_result.buf[0] == '/'; } + if (is_trivial) + trace2_data_intmax("fsm_hook", NULL, + "query/trivial-response", 1); + trace_performance_since(last_update, "fsmonitor process '%s'", core_fsmonitor); trace_printf_key(&trace_fsmonitor, "fsmonitor process '%s' returned %s", core_fsmonitor, query_success ? "success" : "failure"); } - /* a fsmonitor process can return '/' to indicate all entries are invalid */ - if (query_success && query_result.buf[bol] != '/') { - /* Mark all entries returned by the monitor as dirty */ + /* + * The response from FSMonitor (excluding the header token) is + * either: + * + * [a] a (possibly empty) list of NUL delimited relative + * pathnames of changed paths. This list can contain + * files and directories. Directories have a trailing + * slash. + * + * [b] a single '/' to indicate the provider had no + * information and that we should consider everything + * invalid. We call this a trivial response. + */ + if (query_success && !is_trivial) { + /* + * Mark all pathnames returned by the monitor as dirty. + * + * This updates both the cache-entries and the untracked-cache. + */ buf = query_result.buf; for (i = bol; i < query_result.len; i++) { if (buf[i] != '\0') @@ -318,11 +328,16 @@ void refresh_fsmonitor(struct index_state *istate) if (istate->untracked) istate->untracked->use_fsmonitor = 1; } else { - - /* We only want to run the post index changed hook if we've actually changed entries, so keep track - * if we actually changed entries or not */ + /* + * We failed to get a response or received a trivial response, + * so invalidate everything. + * + * We only want to run the post index changed hook if + * we've actually changed entries, so keep track if we + * actually changed entries or not. + */ int is_cache_changed = 0; - /* Mark all entries invalid */ + for (i = 0; i < istate->cache_nr; i++) { if (istate->cache[i]->ce_flags & CE_FSMONITOR_VALID) { is_cache_changed = 1; @@ -330,7 +345,10 @@ void refresh_fsmonitor(struct index_state *istate) } } - /* If we're going to check every file, ensure we save the results */ + /* + * If we're going to check every file, ensure we save + * the results. + */ if (is_cache_changed) istate->cache_changed |= FSMONITOR_CHANGED; -- cgit v1.2.3