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[PATCH v2 07/19] make sure partially read index is not changed

From
Thomas Gummerer <t.gummerer@gmail.com>
Date
Jul 12, 2013, 17:26 UTC
Message-ID
<1373650024-3001-8-git-send-email-t.gummerer@gmail.com>
In-Reply-To
<1373650024-3001-1-git-send-email-t.gummerer@gmail.com>

A partially read index file currently cannot be written to disk. Make sure that never happens, by erroring out when a caller tries to change a partially read index. The caller is responsible for reading the whole index when it's trying to change it later.

Forcing the caller to load the right part of the index file instead of re-reading it when changing it, gives a bit of a performance advantage, by avoiding to read parts of the index twice.

Signed-off-by: Thomas Gummerer <t.gummerer@gmail.com>
---
 builtin/update-index.c |  4 ++++
 cache.h                |  1 +
 read-cache-v2.c        |  2 ++
 read-cache.c           | 10 ++++++++++
 4 files changed, 17 insertions(+)
diff --git a/builtin/update-index.c b/builtin/update-index.c
index 5c7762e..4c6e3a6 100644
--- a/builtin/update-index.c
+++ b/builtin/update-index.c
@@ -49,6 +49,8 @@ static int mark_ce_flags(const char *path, int flag, int mark)
 	int namelen = strlen(path);
 	int pos = cache_name_pos(path, namelen);
 	if (0 <= pos) {
+		if (active_cache_partially_read)
+			die("BUG: Can't change a partially read index");
 		if (mark)
 			active_cache[pos]->ce_flags |= flag;
 		else
@@ -253,6 +255,8 @@ static void chmod_path(int flip, const char *path)
 	pos = cache_name_pos(path, strlen(path));
 	if (pos < 0)
 		goto fail;
+	if (active_cache_partially_read)
+		die("BUG: Can't change a partially read index");
 	ce = active_cache[pos];
 	mode = ce->ce_mode;
 	if (!S_ISREG(mode))
diff --git a/cache.h b/cache.h
index d305d21..455b772 100644
--- a/cache.h
+++ b/cache.h
@@ -311,6 +311,7 @@ extern void free_name_hash(struct index_state *istate);
 #define active_alloc (the_index.cache_alloc)
 #define active_cache_changed (the_index.cache_changed)
 #define active_cache_tree (the_index.cache_tree)
+#define active_cache_partially_read (the_index.filter_opts)
 
 #define read_cache() read_index(&the_index)
 #define read_cache_from(path) read_index_from(&the_index, (path))
diff --git a/read-cache-v2.c b/read-cache-v2.c
index 51b618f..f3c0685 100644
--- a/read-cache-v2.c
+++ b/read-cache-v2.c
@@ -479,6 +479,8 @@ static int write_index_v2(struct index_state *istate, int newfd)
 	struct stat st;
 	struct strbuf previous_name_buf = STRBUF_INIT, *previous_name;
 
+	if (istate->filter_opts)
+		die("BUG: index: cannot write a partially read index");
 	for (i = removed = extended = 0; i < entries; i++) {
 		if (cache[i]->ce_flags & CE_REMOVE)
 			removed++;
diff --git a/read-cache.c b/read-cache.c
index 9053d43..ab716ed 100644
--- a/read-cache.c
+++ b/read-cache.c
@@ -30,6 +30,8 @@ static void replace_index_entry(struct index_state *istate, int nr, struct cache
 {
 	struct cache_entry *old = istate->cache[nr];
 
+	if (istate->filter_opts)
+		die("BUG: Can't change a partially read index");
 	remove_name_hash(istate, old);
 	set_index_entry(istate, nr, ce);
 	istate->cache_changed = 1;
@@ -467,6 +469,8 @@ int remove_index_entry_at(struct index_state *istate, int pos)
 {
 	struct cache_entry *ce = istate->cache[pos];
 
+	if (istate->filter_opts)
+		die("BUG: Can't change a partially read index");
 	record_resolve_undo(istate, ce);
 	remove_name_hash(istate, ce);
 	istate->cache_changed = 1;
@@ -973,6 +977,8 @@ int add_index_entry(struct index_state *istate, struct cache_entry *ce, int opti
 {
 	int pos;
 
+	if (istate->filter_opts)
+		die("BUG: Can't change a partially read index");
 	if (option & ADD_CACHE_JUST_APPEND)
 		pos = istate->cache_nr;
 	else {
@@ -1173,6 +1179,8 @@ int refresh_index(struct index_state *istate, unsigned int flags, const char **p
 				/* If we are doing --really-refresh that
 				 * means the index is not valid anymore.
 				 */
+				if (istate->filter_opts)
+					die("BUG: Can't change a partially read index");
 				ce->ce_flags &= ~CE_VALID;
 				istate->cache_changed = 1;
 			}
@@ -1331,6 +1339,8 @@ int read_index_filtered_from(struct index_state *istate, const char *path,
 	void *mmap;
 	size_t mmap_size;
 
+	if (istate->filter_opts)
+		die("BUG: Can't re-read partially read index");
 	errno = EBUSY;
 	if (istate->initialized)
 		return istate->cache_nr;

-- 
1.8.3.453.g1dfc63d
Previous: Duy NguyenNext: Duy Nguyen
Message 11 of 51 in “Index-v5”
  1. 00/19 Index-v5Thomas Gummerer, Jul 12, 2013
  2. 01/19 t2104: Don't fail for index versions other than [23]Thomas Gummerer, Jul 12, 2013
  3. 02/19 read-cache: split index file version specific functionalityThomas Gummerer, Jul 12, 2013
  4. 03/19 read-cache: move index v2 specific functions to their own fileThomas Gummerer, Jul 12, 2013
  5. Duy NguyenJul 14, 2013
  6. Thomas GummererJul 19, 2013
  7. 04/19 read-cache: Re-read index if index file changedThomas Gummerer, Jul 12, 2013
  8. 05/19 Add documentation for the index apiThomas Gummerer, Jul 12, 2013
  9. 06/19 read-cache: add index reading apiThomas Gummerer, Jul 12, 2013
  10. Duy NguyenJul 14, 2013
  11. 07/19 make sure partially read index is not changedThomas Gummerer, Jul 12, 2013
  12. Duy NguyenJul 14, 2013
  13. Thomas GummererJul 17, 2013
  14. 08/19 grep.c: Use index apiThomas Gummerer, Jul 12, 2013
  15. Duy NguyenJul 14, 2013
  16. Thomas GummererJul 15, 2013
  17. 09/19 ls-files.c: use index apiThomas Gummerer, Jul 12, 2013
  18. Duy NguyenJul 14, 2013
  19. Thomas GummererJul 17, 2013
  20. 10/19 documentation: add documentation of the index-v5 file formatThomas Gummerer, Jul 12, 2013
  21. Duy NguyenJul 14, 2013
  22. Thomas GummererJul 17, 2013
  23. Duy NguyenAug 4, 2013
  24. Thomas GummererAug 4, 2013
  25. 11/19 read-cache: make in-memory format aware of stat_crcThomas Gummerer, Jul 12, 2013
  26. 12/19 read-cache: read index-v5Thomas Gummerer, Jul 12, 2013
  27. Duy NguyenJul 14, 2013
  28. Thomas GummererAug 7, 2013
  29. Duy NguyenJul 15, 2013
  30. Thomas GummererJul 17, 2013
  31. Duy NguyenAug 8, 2013
  32. Thomas GummererAug 8, 2013
  33. Thomas GummererAug 9, 2013
  34. Thomas GummererAug 7, 2013
  35. Duy NguyenAug 8, 2013
  36. 13/19 read-cache: read resolve-undo dataThomas Gummerer, Jul 12, 2013
  37. 14/19 read-cache: read cache-tree in index-v5Thomas Gummerer, Jul 12, 2013
  38. 15/19 read-cache: write index-v5Thomas Gummerer, Jul 12, 2013
  39. 16/19 read-cache: write index-v5 cache-tree dataThomas Gummerer, Jul 12, 2013
  40. 17/19 read-cache: write resolve-undo data for index-v5Thomas Gummerer, Jul 12, 2013
  41. 18/19 update-index.c: rewrite index when index-version is givenThomas Gummerer, Jul 12, 2013
  42. 19/19 p0003-index.sh: add perf test for the index formatsThomas Gummerer, Jul 12, 2013
  43. Duy NguyenJul 14, 2013
  44. Thomas GummererJul 15, 2013
  45. Duy NguyenJul 15, 2013
  46. Thomas GummererJul 17, 2013
  47. Junio C HamanoJul 17, 2013
  48. Thomas GummererJul 19, 2013
  49. Junio C HamanoJul 19, 2013
  50. Ramsay JonesJul 16, 2013
  51. Thomas GummererJul 17, 2013

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