diff options
author | Ronnie Sahlberg <sahlberg@google.com> | 2014-05-15 10:29:33 -0700 |
---|---|---|
committer | Junio C Hamano <gitster@pobox.com> | 2014-05-15 14:11:31 -0700 |
commit | 99edbbe41193a1c23ac3cc8b92e383dd59ebec56 (patch) | |
tree | 0e6d87866c517ec52f2ba47893313c2d71d32c01 | |
parent | 6436cba1234df1e513046fb1e79206ebb992ca84 (diff) | |
download | git-99edbbe41193a1c23ac3cc8b92e383dd59ebec56.tar.gz |
branch.c: use ref transaction for all ref updates
Change create_branch to use a ref transaction when creating the new branch.
ref_transaction_create will check that the ref does not already exist and fail
otherwise meaning that we no longer need to keep a lock on the ref during the
setup_tracking. This simplifies the code since we can now do the transaction
in one single step.
If the forcing flag is false then use ref_transaction_create since this will
fail if the ref already exist. Otherwise use ref_transaction_update.
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 existsing. 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>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
-rw-r--r-- | branch.c | 30 |
1 files changed, 16 insertions, 14 deletions
@@ -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 +291,25 @@ 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(); + if (!transaction || + ref_transaction_update(transaction, ref.buf, sha1, + null_sha1, 0, !forcing) || + ref_transaction_commit(transaction, msg, &err)) + die_errno(_("%s: failed to write ref: %s"), + ref.buf, err.buf); + } + 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); } |