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From: Michal Suchanek <msuchanek@suse.de>
To: git@vger.kernel.org
Cc: "Michal Suchanek" <msuchanek@suse.de>,
	"Eric Sunshine" <sunshine@sunshineco.com>,
	"Marketa Calabkova" <mcalabkova@suse.cz>,
	"Nguyễn Thái Ngọc Duy" <pclouds@gmail.com>,
	"Junio C Hamano" <gitster@pobox.com>
Subject: [PATCH 1/2] worktree: fix worktree add race.
Date: Mon, 18 Feb 2019 18:04:56 +0100	[thread overview]
Message-ID: <c7c66ca1f954e20dad8eeec3fb10c53ad844c800.1550508544.git.msuchanek@suse.de> (raw)
In-Reply-To: <cover.1550508544.git.msuchanek@suse.de>

Git runs a stat loop to find a worktree name that's available and then does
mkdir on the found name. Turn it to mkdir loop to avoid another invocation of
worktree add finding the same free name and creating the directory first.

Signed-off-by: Michal Suchanek <msuchanek@suse.de>
---
v2:
- simplify loop exit condition
- exit early if the mkdir fails for reason other than already present
worktree
- make counter unsigned
---
 builtin/worktree.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/builtin/worktree.c b/builtin/worktree.c
index 3f9907fcc994..85a604cfe98c 100644
--- a/builtin/worktree.c
+++ b/builtin/worktree.c
@@ -268,10 +268,10 @@ static int add_worktree(const char *path, const char *refname,
 	struct strbuf sb_git = STRBUF_INIT, sb_repo = STRBUF_INIT;
 	struct strbuf sb = STRBUF_INIT;
 	const char *name;
-	struct stat st;
 	struct child_process cp = CHILD_PROCESS_INIT;
 	struct argv_array child_env = ARGV_ARRAY_INIT;
-	int counter = 0, len, ret;
+	unsigned int counter = 0;
+	int len, ret;
 	struct strbuf symref = STRBUF_INIT;
 	struct commit *commit = NULL;
 	int is_branch = 0;
@@ -295,8 +295,12 @@ static int add_worktree(const char *path, const char *refname,
 	if (safe_create_leading_directories_const(sb_repo.buf))
 		die_errno(_("could not create leading directories of '%s'"),
 			  sb_repo.buf);
-	while (!stat(sb_repo.buf, &st)) {
+
+	while (mkdir(sb_repo.buf, 0777)) {
 		counter++;
+		if ((errno != EEXIST) || !counter /* overflow */)
+			die_errno(_("could not create directory of '%s'"),
+				  sb_repo.buf);
 		strbuf_setlen(&sb_repo, len);
 		strbuf_addf(&sb_repo, "%d", counter);
 	}
@@ -306,8 +310,6 @@ static int add_worktree(const char *path, const char *refname,
 	atexit(remove_junk);
 	sigchain_push_common(remove_junk_on_signal);
 
-	if (mkdir(sb_repo.buf, 0777))
-		die_errno(_("could not create directory of '%s'"), sb_repo.buf);
 	junk_git_dir = xstrdup(sb_repo.buf);
 	is_junk = 1;
 
-- 
2.20.1


  reply	other threads:[~2019-02-18 17:05 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-02-18 17:04 [PATCH 0/2] worktree add race fix Michal Suchanek
2019-02-18 17:04 ` Michal Suchanek [this message]
2019-02-18 17:04 ` [PATCH 2/2] setup: don't fail if commondir reference is deleted Michal Suchanek
2019-02-18 21:00   ` Eric Sunshine
2019-02-21 10:50   ` Duy Nguyen
2019-02-21 13:50     ` Michal Suchánek
2019-02-21 17:07       ` Phillip Wood
2019-02-21 17:12         ` Eric Sunshine
2019-02-21 17:27           ` Phillip Wood
2019-03-04 13:30             ` Michal Suchánek
2019-02-21 17:33           ` Michal Suchánek
2019-02-22  9:32         ` Duy Nguyen
2019-02-22 10:20           ` Phillip Wood
2019-02-22  9:26       ` Duy Nguyen
2019-02-20 16:16 ` [PATCH v3 1/2] worktree: fix worktree add race Michal Suchanek
2019-02-20 16:34   ` Eric Sunshine
2019-02-20 17:29     ` Michal Suchánek
2019-03-08  9:20   ` Duy Nguyen
2019-03-08  9:37     ` Eric Sunshine
2019-03-11  1:55     ` Junio C Hamano
2019-02-20 16:16 ` [PATCH v3 2/2] setup: don't fail if commondir reference is deleted Michal Suchanek
2019-02-20 16:55   ` Eric Sunshine
2019-02-20 17:16     ` Michal Suchánek
2019-02-20 18:35       ` Eric Sunshine
2019-02-21  9:27         ` Eric Sunshine
2019-02-21 11:13           ` Michal Suchánek
2019-02-21 11:19         ` Michal Suchánek
  -- strict thread matches above, loose matches on Subject: below --
2019-02-15 18:16 [PATCH 1/2] worktree: fix worktree add race Michal Suchanek
2019-02-15 18:59 ` Junio C Hamano
2019-02-16  0:18   ` Michal Suchánek
2019-02-17  7:05   ` Eric Sunshine

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