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authorRonnie Sahlberg <sahlberg@google.com>2014-04-16 16:21:53 -0700
committerJunio C Hamano <gitster@pobox.com>2014-09-03 10:04:13 -0700
commitd43f990fac72264c1553beb7dbc6e8e795083d42 (patch)
tree50444f39e8722dce38c4b8961e4aac9c3de2933e /branch.c
parentde7e86f522ea806ef40b3c9557e040d4109e55fb (diff)
downloadgit-d43f990fac72264c1553beb7dbc6e8e795083d42.tar.gz
branch.c: use ref transaction for all ref updates
Change create_branch to use a ref transaction when creating the new branch. This also fixes a race condition in the old code where two concurrent create_branch could race since the lock_any_ref_for_update/write_ref_sha1 did not protect against the ref already existing. I.e. one thread could end up overwriting a branch even if the forcing flag is false. Signed-off-by: Ronnie Sahlberg <sahlberg@google.com> Reviewed-by: Michael Haggerty <mhagger@alum.mit.edu> Signed-off-by: Jonathan Nieder <jrnieder@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Diffstat (limited to 'branch.c')
-rw-r--r--branch.c31
1 files changed, 17 insertions, 14 deletions
diff --git a/branch.c b/branch.c
index 660097bc29..37ac555324 100644
--- a/branch.c
+++ b/branch.c
@@ -226,7 +226,6 @@ void create_branch(const char *head,
int force, int reflog, int clobber_head,
int quiet, enum branch_track track)
{
- struct ref_lock *lock = NULL;
struct commit *commit;
unsigned char sha1[20];
char *real_ref, msg[PATH_MAX + 20];
@@ -285,15 +284,6 @@ void create_branch(const char *head,
die(_("Not a valid branch point: '%s'."), start_name);
hashcpy(sha1, commit->object.sha1);
- if (!dont_change_ref) {
- lock = lock_any_ref_for_update(ref.buf, NULL, 0, NULL);
- if (!lock)
- die_errno(_("Failed to lock ref for update"));
- }
-
- if (reflog)
- log_all_ref_updates = 1;
-
if (forcing)
snprintf(msg, sizeof msg, "branch: Reset to %s",
start_name);
@@ -301,13 +291,26 @@ void create_branch(const char *head,
snprintf(msg, sizeof msg, "branch: Created from %s",
start_name);
+ if (reflog)
+ log_all_ref_updates = 1;
+
+ if (!dont_change_ref) {
+ struct ref_transaction *transaction;
+ struct strbuf err = STRBUF_INIT;
+
+ transaction = ref_transaction_begin(&err);
+ if (!transaction ||
+ ref_transaction_update(transaction, ref.buf, sha1,
+ null_sha1, 0, !forcing, &err) ||
+ ref_transaction_commit(transaction, msg, &err))
+ die("%s", err.buf);
+ ref_transaction_free(transaction);
+ strbuf_release(&err);
+ }
+
if (real_ref && track)
setup_tracking(ref.buf + 11, real_ref, track, quiet);
- if (!dont_change_ref)
- if (write_ref_sha1(lock, sha1, msg) < 0)
- die_errno(_("Failed to write ref"));
-
strbuf_release(&ref);
free(real_ref);
}