diff options
| -rw-r--r-- | fsmonitor.c | 35 |
1 files changed, 32 insertions, 3 deletions
diff --git a/fsmonitor.c b/fsmonitor.c index 64deeda597..e12214b300 100644 --- a/fsmonitor.c +++ b/fsmonitor.c @@ -343,16 +343,45 @@ void refresh_fsmonitor(struct index_state *istate) istate->fsmonitor_last_update = strbuf_detach(&last_update_token, NULL); } +/* + * The caller wants to turn on FSMonitor. And when the caller writes + * the index to disk, a FSMonitor extension should be included. This + * requires that `istate->fsmonitor_last_update` not be NULL. But we + * have not actually talked to a FSMonitor process yet, so we don't + * have an initial value for this field. + * + * For a protocol V1 FSMonitor process, this field is a formatted + * "nanoseconds since epoch" field. However, for a protocol V2 + * FSMonitor process, this field is an opaque token. + * + * Historically, `add_fsmonitor()` has initialized this field to the + * current time for protocol V1 processes. There are lots of race + * conditions here, but that code has shipped... + * + * The only true solution is to use a V2 FSMonitor and get a current + * or default token value (that it understands), but we cannot do that + * until we have actually talked to an instance of the FSMonitor process + * (but the protocol requires that we send a token first...). + * + * For simplicity, just initialize like we have a V1 process and require + * that V2 processes adapt. + */ +static void initialize_fsmonitor_last_update(struct index_state *istate) +{ + struct strbuf last_update = STRBUF_INIT; + + strbuf_addf(&last_update, "%"PRIu64"", getnanotime()); + istate->fsmonitor_last_update = strbuf_detach(&last_update, NULL); +} + void add_fsmonitor(struct index_state *istate) { unsigned int i; - struct strbuf last_update = STRBUF_INIT; if (!istate->fsmonitor_last_update) { trace_printf_key(&trace_fsmonitor, "add fsmonitor"); istate->cache_changed |= FSMONITOR_CHANGED; - strbuf_addf(&last_update, "%"PRIu64"", getnanotime()); - istate->fsmonitor_last_update = strbuf_detach(&last_update, NULL); + initialize_fsmonitor_last_update(istate); /* reset the fsmonitor state */ for (i = 0; i < istate->cache_nr; i++) |