This makes both git-fetch and git-push (fetch-pack and receive-pack)
safe against a possible race with aparallel git-repack -a -d that could
prune the new pack while it is not yet referenced, and remove the .keep
file after refs have been updated.
Signed-off-by: Nicolas Pitre <nico@xxxxxxx>
---
Documentation/git-index-pack.txt | 11 ++++
git-fetch.sh | 10 ++++-
index-pack.c | 38 +++++++++------
receive-pack.c | 96 +++++++++++++++++++++++++++++---------
4 files changed, 116 insertions(+), 39 deletions(-)
diff --git a/Documentation/git-index-pack.txt b/Documentation/git-index-pack.txt
index 1235416..2229ee8 100644
--- a/Documentation/git-index-pack.txt
+++ b/Documentation/git-index-pack.txt
@@ -69,6 +69,17 @@ OPTIONS
locate any which have outlived their usefulness.
+Note
+----
+
+Once the index has been created, the list of object names is sorted
+and the SHA1 hash of that list is printed to stdout. If --stdin was
+also used then this is prefixed by either "pack\t", or "keep\t" if a
+new .keep file was successfully created. This is useful to remove a
+.keep file used as a lock to prevent the race with gitlink:git-repack[1]
+mentioned above.
+
+
Author
------
Written by Sergey Vlasov <vsu@xxxxxxxxxxx>
diff --git a/git-fetch.sh b/git-fetch.sh
index 2b5538f..e8ce296 100755
--- a/git-fetch.sh
+++ b/git-fetch.sh
@@ -51,7 +51,7 @@ do
verbose=Yes
;;
-k|--k|--ke|--kee|--keep)
- keep=--keep
+ keep=-k -k
;;
--reflog-action=*)
rloga=`expr "z$1" : 'z-[^=]*=\(.*\)'`
@@ -368,6 +368,7 @@ fetch_main () {
;; # we are already done.
*)
( : subshell because we muck with IFS
+ pack_lockfile=
IFS=" $LF"
(
git-fetch-pack --thin $exec $keep "$remote" $rref || echo failed "$remote"
@@ -378,6 +379,12 @@ fetch_main () {
failed)
echo >&2 "Fetch failure: $remote"
exit 1 ;;
+ # special line coming from index-pack with the pack name
+ pack)
+ continue ;;
+ keep)
+ pack_lockfile="$GIT_OBJECT_DIRECTORY/pack/pack-$remote_name.keep"
+ continue ;;
esac
found=
single_force=
@@ -408,6 +415,7 @@ fetch_main () {
append_fetch_head "$sha1" "$remote" \
"$remote_name" "$remote_nick" "$local_name" "$not_for_merge"
done
+ if [ "$pack_lockfile" ]; then rm -f "$pack_lockfile"; fi
) || exit ;;
esac
diff --git a/index-pack.c b/index-pack.c
index 8d64a88..042aea8 100644
--- a/index-pack.c
+++ b/index-pack.c
@@ -757,6 +757,7 @@ static void final(const char *final_pack
const char *keep_name, const char *keep_msg,
unsigned char *sha1)
{
+ char *report = "pack";
char name[PATH_MAX];
int err;
@@ -767,18 +768,6 @@ static void final(const char *final_pack
if (err)
die("error while closing pack file: %s", strerror(errno));
chmod(curr_pack_name, 0444);
-
- /*
- * Let's just mimic git-unpack-objects here and write
- * the last part of the buffer to stdout.
- */
- while (input_len) {
- err = xwrite(1, input_buffer + input_offset, input_len);
- if (err <= 0)
- break;
- input_len -= err;
- input_offset += err;
- }
}
if (keep_msg) {
@@ -798,6 +787,7 @@ static void final(const char *final_pack
write_or_die(keep_fd, "\n", 1);
}
close(keep_fd);
+ report = "keep";
}
}
@@ -821,6 +811,27 @@ static void final(const char *final_pack
if (move_temp_to_file(curr_index_name, final_index_name))
die("cannot store index file");
}
+
+ if (!from_stdin) {
+ printf("%s\n", sha1_to_hex(sha1));
+ } else {
+ char buf[48];
+ int len = snprintf(buf, sizeof(buf), "%s\t%s\n",
+ report, sha1_to_hex(sha1));
+ xwrite(1, buf, len);
+
+ /*
+ * Let's just mimic git-unpack-objects here and write
+ * the last part of the input buffer to stdout.
+ */
+ while (input_len) {
+ err = xwrite(1, input_buffer + input_offset, input_len);
+ if (err <= 0)
+ break;
+ input_len -= err;
+ input_offset += err;
+ }
+ }
}
int main(int argc, char **argv)
@@ -937,8 +948,5 @@ int main(int argc, char **argv)
free(index_name_buf);
free(keep_name_buf);
- if (!from_stdin)
- printf("%s\n", sha1_to_hex(sha1));
-
return 0;
}
diff --git a/receive-pack.c b/receive-pack.c
index be4c3fb..8bb5683 100644
--- a/receive-pack.c
+++ b/receive-pack.c
@@ -3,8 +3,10 @@
#include "refs.h"
#include "pkt-line.h"
#include "run-command.h"
+#include "exec_cmd.h"
#include "commit.h"
#include "object.h"
+#include <sys/wait.h>
static const char receive_pack_usage[] = "git-receive-pack <git-dir>";
@@ -251,12 +253,13 @@ static const char *parse_pack_header(str
return NULL;
}
+static const char *pack_lockfile;
+
static const char *unpack(void)
{
struct pack_header hdr;
const char *hdr_err;
char hdr_arg[38];
- int code;
hdr_err = parse_pack_header(&hdr);
if (hdr_err)
@@ -265,33 +268,13 @@ static const char *unpack(void)
ntohl(hdr.hdr_version), ntohl(hdr.hdr_entries));
if (ntohl(hdr.hdr_entries) < unpack_limit) {
+ int code;
const char *unpacker[3];
unpacker[0] = "unpack-objects";
unpacker[1] = hdr_arg;
unpacker[2] = NULL;
code = run_command_v_opt(1, unpacker, RUN_GIT_CMD);
- } else {
- const char *keeper[6];
- char my_host[255], keep_arg[128 + 255];
-
- if (gethostname(my_host, sizeof(my_host)))
- strcpy(my_host, "localhost");
- snprintf(keep_arg, sizeof(keep_arg),
- "--keep=receive-pack %i on %s",
- getpid(), my_host);
-
- keeper[0] = "index-pack";
- keeper[1] = "--stdin";
- keeper[2] = "--fix-thin";
- keeper[3] = hdr_arg;
- keeper[4] = keep_arg;
- keeper[5] = NULL;
- code = run_command_v_opt(1, keeper, RUN_GIT_CMD);
- if (!code)
- reprepare_packed_git();
- }
-
- switch (code) {
+ switch (code) {
case 0:
return NULL;
case -ERR_RUN_COMMAND_FORK:
@@ -308,6 +291,71 @@ static const char *unpack(void)
return "unpacker died strangely";
default:
return "unpacker exited with error code";
+ }
+ } else {
+ const char *keeper[6];
+ int fd[2], s, len, status;
+ pid_t pid;
+ char keep_arg[256];
+ char packname[46];
+
+ s = sprintf(keep_arg, "--keep=receive-pack %i on ", getpid());
+ if (gethostname(keep_arg + s, sizeof(keep_arg) - s))
+ strcpy(keep_arg + s, "localhost");
+
+ keeper[0] = "index-pack";
+ keeper[1] = "--stdin";
+ keeper[2] = "--fix-thin";
+ keeper[3] = hdr_arg;
+ keeper[4] = keep_arg;
+ keeper[5] = NULL;
+
+ if (pipe(fd) < 0)
+ return "index-pack pipe failed";
+ pid = fork();
+ if (pid < 0)
+ return "index-pack fork failed";
+ if (!pid) {
+ dup2(fd[1], 1);
+ close(fd[1]);
+ close(fd[0]);
+ execv_git_cmd(keeper);
+ die("execv of index-pack failed");
+ }
+ close(fd[1]);
+
+ /*
+ * The first thing we expects from index-pack's output
+ * is "pack\t%40s\n" or "keep\t%40s\n" (46 bytes) where
+ * %40s is the newly created pack SHA1 name. In the "keep"
+ * case, we need it to remove the corresponding .keep file
+ * later on. If we don't get that then tough luck with it.
+ */
+ for (len = 0;
+ len < 46 && (s = xread(fd[0], packname+len, 46-len)) > 0;
+ len += s);
+ close(fd[0]);
+ if (len == 46 && packname[45] == '\n' &&
+ memcmp(packname, "keep\t", 5) == 0) {
+ char path[PATH_MAX];
+ packname[45] = 0;
+ snprintf(path, sizeof(path), "%s/pack/pack-%s.keep",
+ get_object_directory(), packname + 5);
+ pack_lockfile = xstrdup(path);
+ }
+
+ /* Then wrap our index-pack process. */
+ while (waitpid(pid, &status, 0) < 0)
+ if (errno != EINTR)
+ return "waitpid failed";
+ if (WIFEXITED(status)) {
+ int code = WEXITSTATUS(status);
+ if (code)
+ return "index-pack exited with error code";
+ reprepare_packed_git();
+ return NULL;
+ }
+ return "index-pack abnormal exit";
}
}
@@ -363,6 +411,8 @@ int main(int argc, char **argv)
const char *unpack_status = unpack();
if (!unpack_status)
execute_commands();
+ if (pack_lockfile)
+ unlink(pack_lockfile);
if (report_status)
report(unpack_status);
}
--
1.4.3.3.g87b2-dirty
-
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