A local clone without hardlinks copies all objects, including dangling
ones, to the new repository. Since the mtimes are renewed, those
dangling objects cannot be pruned by "git gc --prune", even if they
would have been old enough for pruning in the original repository.
Instead, preserve mtime during copy. "git gc --prune" will then work
in the clone just like it would have in the original.
Signed-off-by: Clemens Buchacher <drizzd@xxxxxx>
---
I noticed this problem when I cloned a repo with lots of old dangling
objects onto a windows machine. git-gui immediately recommended running
git-gc, and I did. But each time I restarted git-gui, it recommended git-gc
again, because there were still plenty of dangling objects lying around
which could not be removed due to their recent mtimes.
So there is actually a problem with git-gui's recommendation. Especially on
Windows, where it only checks for 1 or more files in .git/objects/42 (as
opposed to 8 files on other platforms). The probability of that happening if
the repo contains about 100 loose objects is 1-(254/255)^100 = 32%. The
probability for the same to happen with at least 2 files is only 6% [*].
Maybe that would be a good compromise?
Alternatively, git-gc could remember the number of dangling objects, and
git-gui can adjust its recommendation accordingly, taking that number and
the date of the lastest repack into account.
Clemens
[*] The following octave script shows the probability for m or more objects
to be in .git/objects/42 for a total of n objects.
m = [1 2 8];
n = 100:100:3000;
P = zeros(length(n), length(m));
for k = 1:length(n)
P(n(k), :) = 1-binocdf(m-1, n(k), 1/255);
end
plot(n, P);
n \ m 1 2 8
100 32% 6% 0%
500 86% 58% 0%
1000 98% 90% 5%
2000 100% 100% 55%
---
builtin-clone.c | 2 +-
builtin-init-db.c | 2 +-
cache.h | 6 ++++--
copy.c | 25 ++++++++++++++++++++++---
lockfile.c | 2 +-
rerere.c | 2 +-
6 files changed, 30 insertions(+), 9 deletions(-)
diff --git a/builtin-clone.c b/builtin-clone.c
index ad04808..cb3c895 100644
--- a/builtin-clone.c
+++ b/builtin-clone.c
@@ -269,7 +269,7 @@ static void copy_or_link_directory(struct strbuf *src, struct strbuf *dest)
die_errno("failed to create link '%s'", dest->buf);
option_no_hardlinks = 1;
}
- if (copy_file(dest->buf, src->buf, 0666))
+ if (copy_file(dest->buf, src->buf, 0666, 1))
die_errno("failed to copy file to '%s'", dest->buf);
}
closedir(dir);
diff --git a/builtin-init-db.c b/builtin-init-db.c
index dd84cae..5deb81d 100644
--- a/builtin-init-db.c
+++ b/builtin-init-db.c
@@ -100,7 +100,7 @@ static void copy_templates_1(char *path, int baselen,
die_errno("cannot symlink '%s' '%s'", lnk, path);
}
else if (S_ISREG(st_template.st_mode)) {
- if (copy_file(path, template, st_template.st_mode))
+ if (copy_file(path, template, st_template.st_mode, 0))
die_errno("cannot copy '%s' to '%s'", template,
path);
}
diff --git a/cache.h b/cache.h
index 5fad24c..1875c97 100644
--- a/cache.h
+++ b/cache.h
@@ -921,8 +921,10 @@ extern const char *git_mailmap_file;
/* IO helper functions */
extern void maybe_flush_or_die(FILE *, const char *);
-extern int copy_fd(int ifd, int ofd);
-extern int copy_file(const char *dst, const char *src, int mode);
+extern int copy_fd(int ifd, int ofd, int preserve_times);
+extern int copy_file(const char *dst, const char *src, int mode, int
+ preserve_times);
+extern int copy_times(int ofd, int ifd);
extern ssize_t read_in_full(int fd, void *buf, size_t count);
extern ssize_t write_in_full(int fd, const void *buf, size_t count);
extern void write_or_die(int fd, const void *buf, size_t count);
diff --git a/copy.c b/copy.c
index e54d15a..fe0380e 100644
--- a/copy.c
+++ b/copy.c
@@ -1,6 +1,6 @@
#include "cache.h"
-int copy_fd(int ifd, int ofd)
+int copy_fd(int ifd, int ofd, int preserve_times)
{
while (1) {
char buffer[8192];
@@ -31,11 +31,18 @@ int copy_fd(int ifd, int ofd)
}
}
}
+ if (preserve_times && copy_times(ofd, ifd)) {
+ int time_error = errno;
+ close(ifd);
+ return error("copy-fd: failed to preserve times: %s",
+ strerror(time_error));
+ }
close(ifd);
return 0;
}
-int copy_file(const char *dst, const char *src, int mode)
+int copy_file(const char *dst, const char *src, int mode,
+ int preserve_times)
{
int fdi, fdo, status;
@@ -46,7 +53,7 @@ int copy_file(const char *dst, const char *src, int mode)
close(fdi);
return fdo;
}
- status = copy_fd(fdi, fdo);
+ status = copy_fd(fdi, fdo, preserve_times);
if (close(fdo) != 0)
return error("%s: close error: %s", dst, strerror(errno));
@@ -55,3 +62,15 @@ int copy_file(const char *dst, const char *src, int mode)
return status;
}
+
+int copy_times(int ofd, int ifd)
+{
+ struct stat st;
+ struct timespec times[2];
+ if (fstat(ifd, &st))
+ return -1;
+ times[0].tv_nsec = UTIME_OMIT;
+ times[1].tv_sec = st.st_mtime;
+ times[1].tv_nsec = ST_MTIME_NSEC(st);
+ return futimens(ofd, times);
+}
diff --git a/lockfile.c b/lockfile.c
index eb931ed..c7bbd4d 100644
--- a/lockfile.c
+++ b/lockfile.c
@@ -196,7 +196,7 @@ int hold_lock_file_for_append(struct lock_file *lk, const char *path, int flags)
close(fd);
return error("cannot open '%s' for copying", path);
}
- } else if (copy_fd(orig_fd, fd)) {
+ } else if (copy_fd(orig_fd, fd, 0)) {
if (flags & LOCK_DIE_ON_ERROR)
exit(128);
close(fd);
diff --git a/rerere.c b/rerere.c
index 87360dc..d25f5f1 100644
--- a/rerere.c
+++ b/rerere.c
@@ -326,7 +326,7 @@ static int do_plain_rerere(struct string_list *rr, int fd)
continue;
fprintf(stderr, "Recorded resolution for '%s'.\n", path);
- copy_file(rerere_path(name, "postimage"), path, 0666);
+ copy_file(rerere_path(name, "postimage"), path, 0666, 0);
mark_resolved:
rr->items[i].util = NULL;
}
--
1.6.4.2.266.gbaa17
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