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[PATCH v2 2/7] sha1_file: drop free_pack_by_name

From
Jeff King <peff@peff.net>
Date
Jul 29, 2016, 04:06 UTC
Message-ID
<20160729040647.GB22408@sigill.intra.peff.net>
In-Reply-To
<20160729040422.GA19678@sigill.intra.peff.net>

The point of this function is to drop an entry from the "packed_git" cache that points to a file we might be overwriting, because our contents may not be the same (and hence the only caller was pack-objects as it moved a temporary packfile into place).

In older versions of git, this could happen because the names of packfiles were derived from the set of objects they contained, not the actual bits on disk. But since 1190a1a (pack-objects: name pack files after trailer hash, 2013-12-05), the name reflects the actual bits on disk, and any two packfiles with the same name can be used interchangeably.

Dropping this function not only saves a few lines of code, it makes the lifetime of "struct packed_git" much easier to reason about: namely, we now do not ever free these structs.

Signed-off-by: Jeff King <peff@peff.net>
---
 cache.h      |  1 -
 pack-write.c |  1 -
 sha1_file.c  | 30 ------------------------------
 3 files changed, 32 deletions(-)
diff --git a/cache.h b/cache.h
index 3855ddf..57ef726 100644
--- a/cache.h
+++ b/cache.h
@@ -1416,7 +1416,6 @@ extern unsigned char *use_pack(struct packed_git *, struct pack_window **, off_t
 extern void close_pack_windows(struct packed_git *);
 extern void close_all_packs(void);
 extern void unuse_pack(struct pack_window **);
-extern void free_pack_by_name(const char *);
 extern void clear_delta_base_cache(void);
 extern struct packed_git *add_packed_git(const char *path, size_t path_len, int local);
 
diff --git a/pack-write.c b/pack-write.c
index 33293ce..ea0b788 100644
--- a/pack-write.c
+++ b/pack-write.c
@@ -354,7 +354,6 @@ void finish_tmp_packfile(struct strbuf *name_buffer,
 		die_errno("unable to make temporary index file readable");
 
 	strbuf_addf(name_buffer, "%s.pack", sha1_to_hex(sha1));
-	free_pack_by_name(name_buffer->buf);
 
 	if (rename(pack_tmp_name, name_buffer->buf))
 		die_errno("unable to rename temporary pack file");
diff --git a/sha1_file.c b/sha1_file.c
index d5e1121..e045d2f 100644
--- a/sha1_file.c
+++ b/sha1_file.c
@@ -891,36 +891,6 @@ void close_pack_index(struct packed_git *p)
 	}
 }
 
-/*
- * This is used by git-repack in case a newly created pack happens to
- * contain the same set of objects as an existing one.  In that case
- * the resulting file might be different even if its name would be the
- * same.  It is best to close any reference to the old pack before it is
- * replaced on disk.  Of course no index pointers or windows for given pack
- * must subsist at this point.  If ever objects from this pack are requested
- * again, the new version of the pack will be reinitialized through
- * reprepare_packed_git().
- */
-void free_pack_by_name(const char *pack_name)
-{
-	struct packed_git *p, **pp = &packed_git;
-
-	while (*pp) {
-		p = *pp;
-		if (strcmp(pack_name, p->pack_name) == 0) {
-			clear_delta_base_cache();
-			close_pack(p);
-			free(p->bad_object_sha1);
-			*pp = p->next;
-			if (last_found_pack == p)
-				last_found_pack = NULL;
-			free(p);
-			return;
-		}
-		pp = &p->next;
-	}
-}
-
 static unsigned int get_max_fd_limit(void)
 {
 #ifdef RLIMIT_NOFILE
-- 
2.9.2.607.g98dce7b
Previous: Jeff KingNext: Jeff King
Message 3 of 35 in “speed up pack-objects counting with many packs”
  1. 0/7 speed up pack-objects counting with many packsJeff King, Jul 29, 2016
  2. 1/7 t/perf: add tests for many-pack scenariosJeff King, Jul 29, 2016
  3. 2/7 sha1_file: drop free_pack_by_nameJeff King, Jul 29, 2016
  4. 3/7 add generic most-recently-used listJeff King, Jul 29, 2016
  5. 4/7 find_pack_entry: replace last_found_pack with MRU cacheJeff King, Jul 29, 2016
  6. 5/7 pack-objects: break out of want_object loop earlyJeff King, Jul 29, 2016
  7. 6/7 pack-objects: compute local/ignore_pack_keep earlyJeff King, Jul 29, 2016
  8. 7/7 pack-objects: use mru list when iterating over packsJeff King, Jul 29, 2016
  9. Jeff KingJul 29, 2016
  10. Junio C HamanoJul 29, 2016
  11. Jeff KingAug 8, 2016
  12. Junio C HamanoAug 8, 2016
  13. Jeff KingAug 8, 2016
  14. Junio C HamanoAug 8, 2016
  15. Jeff KingAug 9, 2016
  16. Jeff KingAug 9, 2016
  17. Junio C HamanoAug 9, 2016
  18. Junio C HamanoAug 9, 2016
  19. 0/2 pack-objects mruJeff King, Aug 10, 2016
  20. Junio C HamanoAug 10, 2016
  21. Jeff KingAug 11, 2016
  22. 1/2 pack-objects: break delta cycles before delta-search phaseJeff King, Aug 10, 2016
  23. Junio C HamanoAug 10, 2016
  24. Jeff KingAug 11, 2016
  25. 1/2 pack-objects: break delta cycles before delta-search phaseJeff King, Aug 11, 2016
  26. Jeff KingAug 11, 2016
  27. pack-objects mruJeff King, Aug 11, 2016
  28. 1/4 provide an initializer for "struct object_info"Jeff King, Aug 11, 2016
  29. 2/4 sha1_file: make packed_object_info publicJeff King, Aug 11, 2016
  30. 3/4 pack-objects: break delta cycles before delta-search phaseJeff King, Aug 11, 2016
  31. 4/4 pack-objects: use mru list when iterating over packsJeff King, Aug 11, 2016
  32. Jeff KingAug 11, 2016
  33. Junio C HamanoAug 11, 2016
  34. Jeff KingAug 11, 2016
  35. 2/2 pack-objects: use mru list when iterating over packsJeff King, Aug 10, 2016

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