From: Michael Haggerty <mhagger@alum.mit.edu>
To: Junio C Hamano <gitster@pobox.com>
Cc: git@vger.kernel.org, Jeff King <peff@peff.net>,
David Turner <novalis@novalis.org>,
Michael Haggerty <mhagger@alum.mit.edu>
Subject: [PATCH v3 07/23] lock_ref_sha1_basic(): use raceproof_create_file()
Date: Sat, 31 Dec 2016 04:12:47 +0100 [thread overview]
Message-ID: <0145c9444cf7eb9e9897e420c9b38ddbe76d4562.1483153436.git.mhagger@alum.mit.edu> (raw)
In-Reply-To: <cover.1483153436.git.mhagger@alum.mit.edu>
Instead of coding the retry loop inline, use raceproof_create_file() to
make lock acquisition safe against directory creation/deletion races.
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
---
refs/files-backend.c | 35 +++++++++--------------------------
1 file changed, 9 insertions(+), 26 deletions(-)
diff --git a/refs/files-backend.c b/refs/files-backend.c
index 7d4658a..74de289 100644
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -1985,6 +1985,13 @@ static int remove_empty_directories(struct strbuf *path)
return remove_dir_recursively(path, REMOVE_DIR_EMPTY_ONLY);
}
+static int create_reflock(const char *path, void *cb)
+{
+ struct lock_file *lk = cb;
+
+ return hold_lock_file_for_update(lk, path, LOCK_NO_DEREF) < 0 ? -1 : 0;
+}
+
/*
* Locks a ref returning the lock on success and NULL on failure.
* On failure errno is set to something meaningful.
@@ -2002,7 +2009,6 @@ static struct ref_lock *lock_ref_sha1_basic(struct files_ref_store *refs,
int last_errno = 0;
int mustexist = (old_sha1 && !is_null_sha1(old_sha1));
int resolve_flags = RESOLVE_REF_NO_RECURSE;
- int attempts_remaining = 3;
int resolved;
assert_main_repository(&refs->base, "lock_ref_sha1_basic");
@@ -2067,35 +2073,12 @@ static struct ref_lock *lock_ref_sha1_basic(struct files_ref_store *refs,
lock->ref_name = xstrdup(refname);
- retry:
- switch (safe_create_leading_directories_const(ref_file.buf)) {
- case SCLD_OK:
- break; /* success */
- case SCLD_VANISHED:
- if (--attempts_remaining > 0)
- goto retry;
- /* fall through */
- default:
+ if (raceproof_create_file(ref_file.buf, create_reflock, lock->lk)) {
last_errno = errno;
- strbuf_addf(err, "unable to create directory for '%s'",
- ref_file.buf);
+ unable_to_lock_message(ref_file.buf, errno, err);
goto error_return;
}
- if (hold_lock_file_for_update(lock->lk, ref_file.buf, LOCK_NO_DEREF) < 0) {
- last_errno = errno;
- if (errno == ENOENT && --attempts_remaining > 0)
- /*
- * Maybe somebody just deleted one of the
- * directories leading to ref_file. Try
- * again:
- */
- goto retry;
- else {
- unable_to_lock_message(ref_file.buf, errno, err);
- goto error_return;
- }
- }
if (verify_lock(lock, old_sha1, mustexist, err)) {
last_errno = errno;
goto error_return;
--
2.9.3
next prev parent reply other threads:[~2016-12-31 3:13 UTC|newest]
Thread overview: 55+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-12-31 3:12 [PATCH v3 00/23] Delete directories left empty after ref deletion Michael Haggerty
2016-12-31 3:12 ` [PATCH v3 01/23] files_rename_ref(): tidy up whitespace Michael Haggerty
2016-12-31 3:12 ` [PATCH v3 02/23] t5505: use "for-each-ref" to test for the non-existence of references Michael Haggerty
2016-12-31 3:12 ` [PATCH v3 03/23] safe_create_leading_directories_const(): preserve errno Michael Haggerty
2016-12-31 3:12 ` [PATCH v3 04/23] safe_create_leading_directories(): set errno on SCLD_EXISTS Michael Haggerty
2016-12-31 3:12 ` [PATCH v3 05/23] raceproof_create_file(): new function Michael Haggerty
2016-12-31 6:11 ` Jeff King
2016-12-31 7:42 ` Michael Haggerty
2017-01-01 2:07 ` Junio C Hamano
2016-12-31 3:12 ` [PATCH v3 06/23] lock_ref_sha1_basic(): inline constant Michael Haggerty
2016-12-31 3:12 ` Michael Haggerty [this message]
2016-12-31 3:12 ` [PATCH v3 08/23] rename_tmp_log(): use raceproof_create_file() Michael Haggerty
2016-12-31 3:12 ` [PATCH v3 09/23] rename_tmp_log(): improve error reporting Michael Haggerty
2016-12-31 3:12 ` [PATCH v3 10/23] log_ref_write(): inline function Michael Haggerty
2017-01-01 2:09 ` Junio C Hamano
2017-01-01 8:41 ` Michael Haggerty
2016-12-31 3:12 ` [PATCH v3 11/23] log_ref_setup(): separate code for create vs non-create Michael Haggerty
2016-12-31 6:26 ` Jeff King
2016-12-31 7:52 ` Michael Haggerty
2017-01-01 3:28 ` Junio C Hamano
2017-01-01 8:45 ` Michael Haggerty
2016-12-31 3:12 ` [PATCH v3 12/23] log_ref_setup(): improve robustness against races Michael Haggerty
2016-12-31 3:12 ` [PATCH v3 13/23] log_ref_setup(): pass the open file descriptor back to the caller Michael Haggerty
2016-12-31 6:32 ` Jeff King
2016-12-31 7:58 ` Michael Haggerty
2016-12-31 17:58 ` Jeff King
2017-01-01 10:36 ` Junio C Hamano
2016-12-31 3:12 ` [PATCH v3 14/23] log_ref_write_1(): don't depend on logfile argument Michael Haggerty
2016-12-31 6:35 ` Jeff King
2016-12-31 8:01 ` Michael Haggerty
2016-12-31 3:12 ` [PATCH v3 15/23] log_ref_setup(): manage the name of the reflog file internally Michael Haggerty
2016-12-31 3:12 ` [PATCH v3 16/23] log_ref_write_1(): inline function Michael Haggerty
2016-12-31 3:12 ` [PATCH v3 17/23] delete_ref_loose(): derive loose reference path from lock Michael Haggerty
2016-12-31 3:12 ` [PATCH v3 18/23] delete_ref_loose(): inline function Michael Haggerty
2016-12-31 3:12 ` [PATCH v3 19/23] try_remove_empty_parents(): rename parameter "name" -> "refname" Michael Haggerty
2016-12-31 3:13 ` [PATCH v3 20/23] try_remove_empty_parents(): don't trash argument contents Michael Haggerty
2016-12-31 6:40 ` Jeff King
2017-01-02 16:27 ` Michael Haggerty
2017-01-02 17:10 ` Jeff King
2016-12-31 3:13 ` [PATCH v3 21/23] try_remove_empty_parents(): don't accommodate consecutive slashes Michael Haggerty
2017-01-01 2:30 ` Junio C Hamano
2017-01-01 5:59 ` Jeff King
2017-01-02 18:06 ` Michael Haggerty
2017-01-02 18:26 ` Jeff King
2016-12-31 3:13 ` [PATCH v3 22/23] try_remove_empty_parents(): teach to remove parents of reflogs, too Michael Haggerty
2016-12-31 3:13 ` [PATCH v3 23/23] files_transaction_commit(): clean up empty directories Michael Haggerty
2016-12-31 6:47 ` [PATCH v3 00/23] Delete directories left empty after ref deletion Jeff King
2017-01-01 2:32 ` Junio C Hamano
2017-01-01 9:24 ` Jacob Keller
2017-01-01 9:26 ` Jacob Keller
2017-01-01 12:43 ` Philip Oakley
2017-01-01 20:36 ` Jacob Keller
2017-01-02 4:19 ` Jeff King
2017-01-02 18:14 ` Michael Haggerty
2017-01-02 18:54 ` Jacob Keller
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