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[PATCH v2] dir.c: ignore paths containing .git when invalidating untracked cache

From
Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Date
Feb 7, 2018, 09:21 UTC
Message-ID
<20180207092141.4312-2-pclouds@gmail.com>
In-Reply-To
<20180207092141.4312-1-pclouds@gmail.com>

read_directory() code ignores all paths named ".git" even if it's not a valid git repository. See treat_path() for details. Since ".git" is basically invisible to read_directory(), when we are asked to invalidate a path that contains ".git", we can safely ignore it because the slow path would not consider it anyway.

This helps when fsmonitor is used and we have a real ".git" repo at worktree top. Occasionally .git/index will be updated and if the fsmonitor hook does not filter it, untracked cache is asked to invalidate the path ".git/index".

Without this patch, we invalidate the root directory unncessarily, which:

- makes read_directory() fall back to slow path for root directory
  (slower)
- makes the index dirty (because UNTR extension is updated). Depending
  on the index size, writing it down could also be slow.

A note about the new "safe_path" knob. Since this new check could be relatively expensive, avoid it when we know it's not needed. If the path comes from the index, it can't contain ".git". If it does contain, we may be screwed up at many more levels, not just this one.

Noticed-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 My v1 was rubbish. It's no wonder Ben didn't see my intention. v2
 corrects the "is .git in a given path?" logic and adds a test to
 verify it.
 dir.c                       | 10 ++++++----
 dir.h                       |  2 +-
 fsmonitor.c                 |  2 +-
 fsmonitor.h                 |  2 +-
 t/t7519-status-fsmonitor.sh | 39 +++++++++++++++++++++++++++++++++++++
 unpack-trees.c              |  2 +-
 6 files changed, 49 insertions(+), 8 deletions(-)
diff --git a/dir.c b/dir.c
index 7c4b45e30e..fce45fc55e 100644
--- a/dir.c
+++ b/dir.c
@@ -1773,7 +1773,7 @@ static enum path_treatment treat_path(struct dir_struct *dir,
 	if (!de)
 		return treat_path_fast(dir, untracked, cdir, istate, path,
 				       baselen, pathspec);
-	if (is_dot_or_dotdot(de->d_name) || !strcmp(de->d_name, ".git"))
+	if (is_dot_or_dotdot(de->d_name) || !fspathcmp(de->d_name, ".git"))
 		return path_none;
 	strbuf_setlen(path, baselen);
 	strbuf_addstr(path, de->d_name);
@@ -2968,10 +2968,12 @@ static int invalidate_one_component(struct untracked_cache *uc,
 }
 
 void untracked_cache_invalidate_path(struct index_state *istate,
-				     const char *path)
+				     const char *path, int safe_path)
 {
 	if (!istate->untracked || !istate->untracked->root)
 		return;
+	if (!safe_path && !verify_path(path))
+		return;
 	invalidate_one_component(istate->untracked, istate->untracked->root,
 				 path, strlen(path));
 }
@@ -2979,13 +2981,13 @@ void untracked_cache_invalidate_path(struct index_state *istate,
 void untracked_cache_remove_from_index(struct index_state *istate,
 				       const char *path)
 {
-	untracked_cache_invalidate_path(istate, path);
+	untracked_cache_invalidate_path(istate, path, 1);
 }
 
 void untracked_cache_add_to_index(struct index_state *istate,
 				  const char *path)
 {
-	untracked_cache_invalidate_path(istate, path);
+	untracked_cache_invalidate_path(istate, path, 1);
 }
 
 /* Update gitfile and core.worktree setting to connect work tree and git dir */
diff --git a/dir.h b/dir.h
index 11a047ba48..06df057054 100644
--- a/dir.h
+++ b/dir.h
@@ -350,7 +350,7 @@ static inline int dir_path_match(const struct dir_entry *ent,
 int cmp_dir_entry(const void *p1, const void *p2);
 int check_dir_entry_contains(const struct dir_entry *out, const struct dir_entry *in);
 
-void untracked_cache_invalidate_path(struct index_state *, const char *);
+void untracked_cache_invalidate_path(struct index_state *, const char *, int safe_path);
 void untracked_cache_remove_from_index(struct index_state *, const char *);
 void untracked_cache_add_to_index(struct index_state *, const char *);
 
diff --git a/fsmonitor.c b/fsmonitor.c
index 0af7c4edba..6d7bcd5d0e 100644
--- a/fsmonitor.c
+++ b/fsmonitor.c
@@ -130,7 +130,7 @@ static void fsmonitor_refresh_callback(struct index_state *istate, const char *n
 	 * as it could be a new untracked file.
 	 */
 	trace_printf_key(&trace_fsmonitor, "fsmonitor_refresh_callback '%s'", name);
-	untracked_cache_invalidate_path(istate, name);
+	untracked_cache_invalidate_path(istate, name, 0);
 }
 
 void refresh_fsmonitor(struct index_state *istate)
diff --git a/fsmonitor.h b/fsmonitor.h
index cd3cc0ccf2..65f3743636 100644
--- a/fsmonitor.h
+++ b/fsmonitor.h
@@ -65,7 +65,7 @@ static inline void mark_fsmonitor_invalid(struct index_state *istate, struct cac
 {
 	if (core_fsmonitor) {
 		ce->ce_flags &= ~CE_FSMONITOR_VALID;
-		untracked_cache_invalidate_path(istate, ce->name);
+		untracked_cache_invalidate_path(istate, ce->name, 1);
 		trace_printf_key(&trace_fsmonitor, "mark_fsmonitor_invalid '%s'", ce->name);
 	}
 }
diff --git a/t/t7519-status-fsmonitor.sh b/t/t7519-status-fsmonitor.sh
index eb2d13bbcf..756beb0d8e 100755
--- a/t/t7519-status-fsmonitor.sh
+++ b/t/t7519-status-fsmonitor.sh
@@ -314,4 +314,43 @@ test_expect_success 'splitting the index results in the same state' '
 	test_cmp expect actual
 '
 
+test_expect_success UNTRACKED_CACHE 'ignore .git changes when invalidating UNTR' '
+	test_create_repo dot-git &&
+	(
+		cd dot-git &&
+		mkdir -p .git/hooks &&
+		: >tracked &&
+		: >modified &&
+		mkdir dir1 &&
+		: >dir1/tracked &&
+		: >dir1/modified &&
+		mkdir dir2 &&
+		: >dir2/tracked &&
+		: >dir2/modified &&
+		write_integration_script &&
+		git config core.fsmonitor .git/hooks/fsmonitor-test &&
+		git update-index --untracked-cache &&
+		git update-index --fsmonitor &&
+		GIT_TRACE_UNTRACKED_STATS="$TRASH_DIRECTORY/trace-before" \
+		git status &&
+		test-dump-untracked-cache >../before
+	) &&
+	cat >>dot-git/.git/hooks/fsmonitor-test <<-\EOF &&
+	printf ".git\0"
+	printf ".git/index\0"
+	printf "dir1/.git\0"
+	printf "dir1/.git/index\0"
+	EOF
+	(
+		cd dot-git &&
+		GIT_TRACE_UNTRACKED_STATS="$TRASH_DIRECTORY/trace-after" \
+		git status &&
+		test-dump-untracked-cache >../after
+	) &&
+	grep "directory invalidation" trace-before >>before &&
+	grep "directory invalidation" trace-after >>after &&
+	# UNTR extension unchanged, dir invalidation count unchanged
+	test_cmp before after
+'
+
 test_done
diff --git a/unpack-trees.c b/unpack-trees.c
index 96c3327f19..9a327696c5 100644
--- a/unpack-trees.c
+++ b/unpack-trees.c
@@ -1506,7 +1506,7 @@ static void invalidate_ce_path(const struct cache_entry *ce,
 	if (!ce)
 		return;
 	cache_tree_invalidate_path(o->src_index, ce->name);
-	untracked_cache_invalidate_path(o->src_index, ce->name);
+	untracked_cache_invalidate_path(o->src_index, ce->name, 1);
 }
 
 /*

-- 
2.16.1.207.gedba492059
Previous: Nguyễn Thái Ngọc DuyNext: Ben Peart
Message 22 of 30 in “Some rough edges of core.fsmonitor”
  1. Ævar Arnfjörð BjarmasonJan 27, 2018
  2. Duy NguyenJan 27, 2018
  3. trace: measure where the time is spent in the index-heavy operationsNguyễn Thái Ngọc Duy, Jan 27, 2018
  4. Thomas GummererJan 27, 2018
  5. trace: measure where the time is spent in the index-heavy operationsNguyễn Thái Ngọc Duy, Jan 27, 2018
  6. Ævar Arnfjörð BjarmasonJan 27, 2018
  7. Duy NguyenJan 27, 2018
  8. Duy NguyenJan 27, 2018
  9. Ævar Arnfjörð BjarmasonJan 27, 2018
  10. Ben PeartJan 30, 2018
  11. Duy NguyenJan 29, 2018
  12. Ben PeartJan 29, 2018
  13. Duy NguyenFeb 1, 2018
  14. Johannes SchindelinJan 28, 2018
  15. Ævar Arnfjörð BjarmasonJan 28, 2018
  16. Ben PeartJan 30, 2018
  17. Duy NguyenJan 31, 2018
  18. dir.c: ignore paths containing .git when invalidating untracked cacheNguyễn Thái Ngọc Duy, Feb 4, 2018
  19. Ben PeartFeb 5, 2018
  20. Duy NguyenFeb 6, 2018
  21. dir.c: ignore paths containing .git when invalidating untracked cacheNguyễn Thái Ngọc Duy, Feb 7, 2018
  22. dir.c: ignore paths containing .git when invalidating untracked cacheNguyễn Thái Ngọc Duy, Feb 7, 2018
  23. Ben PeartFeb 7, 2018
  24. Duy NguyenFeb 13, 2018
  25. Junio C HamanoFeb 13, 2018
  26. Duy NguyenFeb 14, 2018
  27. Junio C HamanoFeb 14, 2018
  28. Ben PeartJan 30, 2018
  29. Ævar Arnfjörð BjarmasonJan 30, 2018
  30. Ben PeartJan 31, 2018

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