From cae70acf2431f0c31e5c097b96fa5bd752526e6d Mon Sep 17 00:00:00 2001 From: Derrick Stolee Date: Sat, 23 Jan 2021 19:58:14 +0000 Subject: [PATCH] fsmonitor: de-duplicate BUG()s around dirty bits The index has an fsmonitor_dirty bitmap that records which index entries are "dirty" based on the response from the FSMonitor. If this bitmap ever grows larger than the index, then there was an error in how it was constructed, and it was probably a developer's bug. There are several BUG() statements that are very similar, so replace these uses with a simpler assert_index_minimum(). Since there is one caller that uses a custom 'pos' value instead of the bit_size member, we cannot simplify it too much. However, the error string is identical in each, so this simplifies things. Be sure to add one when checking if a position if valid, since the minimum is a bound on the expected size. The end result is that the code is simpler to read while also preserving these assertions for developers in the FSMonitor space. Signed-off-by: Derrick Stolee Signed-off-by: Junio C Hamano --- fsmonitor.c | 27 +++++++++++++-------------- 1 file changed, 13 insertions(+), 14 deletions(-) diff --git a/fsmonitor.c b/fsmonitor.c index ca031c3abb..fe9e9d7baf 100644 --- a/fsmonitor.c +++ b/fsmonitor.c @@ -13,14 +13,19 @@ struct trace_key trace_fsmonitor = TRACE_KEY_INIT(FSMONITOR); +static void assert_index_minimum(struct index_state *istate, size_t pos) +{ + if (pos > istate->cache_nr) + BUG("fsmonitor_dirty has more entries than the index (%"PRIuMAX" > %u)", + (uintmax_t)pos, istate->cache_nr); +} + static void fsmonitor_ewah_callback(size_t pos, void *is) { struct index_state *istate = (struct index_state *)is; struct cache_entry *ce; - if (pos >= istate->cache_nr) - BUG("fsmonitor_dirty has more entries than the index (%"PRIuMAX" >= %u)", - (uintmax_t)pos, istate->cache_nr); + assert_index_minimum(istate, pos + 1); ce = istate->cache[pos]; ce->ce_flags &= ~CE_FSMONITOR_VALID; @@ -82,10 +87,8 @@ int read_fsmonitor_extension(struct index_state *istate, const void *data, } istate->fsmonitor_dirty = fsmonitor_dirty; - if (!istate->split_index && - istate->fsmonitor_dirty->bit_size > istate->cache_nr) - BUG("fsmonitor_dirty has more entries than the index (%"PRIuMAX" > %u)", - (uintmax_t)istate->fsmonitor_dirty->bit_size, istate->cache_nr); + if (!istate->split_index) + assert_index_minimum(istate, istate->fsmonitor_dirty->bit_size); trace_printf_key(&trace_fsmonitor, "read fsmonitor extension successful"); return 0; @@ -110,10 +113,8 @@ void write_fsmonitor_extension(struct strbuf *sb, struct index_state *istate) uint32_t ewah_size = 0; int fixup = 0; - if (!istate->split_index && - istate->fsmonitor_dirty->bit_size > istate->cache_nr) - BUG("fsmonitor_dirty has more entries than the index (%"PRIuMAX" > %u)", - (uintmax_t)istate->fsmonitor_dirty->bit_size, istate->cache_nr); + if (!istate->split_index) + assert_index_minimum(istate, istate->fsmonitor_dirty->bit_size); put_be32(&hdr_version, INDEX_EXTENSION_VERSION2); strbuf_add(sb, &hdr_version, sizeof(uint32_t)); @@ -335,9 +336,7 @@ void tweak_fsmonitor(struct index_state *istate) } /* Mark all previously saved entries as dirty */ - if (istate->fsmonitor_dirty->bit_size > istate->cache_nr) - BUG("fsmonitor_dirty has more entries than the index (%"PRIuMAX" > %u)", - (uintmax_t)istate->fsmonitor_dirty->bit_size, istate->cache_nr); + assert_index_minimum(istate, istate->fsmonitor_dirty->bit_size); ewah_each_bit(istate->fsmonitor_dirty, fsmonitor_ewah_callback, istate); refresh_fsmonitor(istate);