git@vger.kernel.org mailing list mirror (one of many)
 help / color / mirror / code / Atom feed
From: Duy Nguyen <pclouds@gmail.com>
To: Michal Suchanek <msuchanek@suse.de>
Cc: Git Mailing List <git@vger.kernel.org>,
	Eric Sunshine <sunshine@sunshineco.com>,
	Marketa Calabkova <mcalabkova@suse.cz>,
	Junio C Hamano <gitster@pobox.com>
Subject: Re: [PATCH 2/2] setup: don't fail if commondir reference is deleted.
Date: Thu, 21 Feb 2019 17:50:38 +0700	[thread overview]
Message-ID: <CACsJy8AWezO7TFq8ne1a2pSAJZoc6oYqnNNxmVW_FkA9--ntbQ@mail.gmail.com> (raw)
In-Reply-To: <6f9c8775817117c2b36539eb048e2462a650ab8f.1550508544.git.msuchanek@suse.de>

On Tue, Feb 19, 2019 at 12:05 AM Michal Suchanek <msuchanek@suse.de> wrote:
>
> When adding wotktrees git can die in get_common_dir_noenv while
> examining existing worktrees because the commondir file does not exist.
> Rather than testing if the file exists before reading it handle ENOENT.

I don't think we could go around fixing every access to incomplete
worktrees like this. If this is because of racy 'worktree add', then
perhaps a better solution is make it absolutely clear it's not ready
for anybody to access.

For example, we can suffix the worktree directory name with ".lock"
and make sure get_worktrees() ignores entries ending with ".lock".
That should protect other commands while 'worktree add' is still
running. Only when the worktree is complete that 'worktree add' should
rename the directory to lose ".lock" and run external commands like
git-checkout to populate the worktree.

> Signed-off-by: Michal Suchanek <msuchanek@suse.de>
> ---
> v2:
> - do not test file existence first, just read it and handle ENOENT.
> - handle zero size file correctly
> ---
>  setup.c | 16 +++++++++++-----
>  1 file changed, 11 insertions(+), 5 deletions(-)
>
> diff --git a/setup.c b/setup.c
> index ca9e8a949ed8..dd865f280d34 100644
> --- a/setup.c
> +++ b/setup.c
> @@ -270,12 +270,20 @@ int get_common_dir_noenv(struct strbuf *sb, const char *gitdir)
>  {
>         struct strbuf data = STRBUF_INIT;
>         struct strbuf path = STRBUF_INIT;
> -       int ret = 0;
> +       int ret;
>
>         strbuf_addf(&path, "%s/commondir", gitdir);
> -       if (file_exists(path.buf)) {
> -               if (strbuf_read_file(&data, path.buf, 0) <= 0)
> +       ret = strbuf_read_file(&data, path.buf, 0);
> +       if (ret <= 0) {
> +               /*
> +                * if file is missing or zero size (just being written)
> +                * assume default, bail otherwise
> +                */
> +               if (ret && errno != ENOENT)
>                         die_errno(_("failed to read %s"), path.buf);
> +               strbuf_addstr(sb, gitdir);
> +               ret = 0;
> +       } else {
>                 while (data.len && (data.buf[data.len - 1] == '\n' ||
>                                     data.buf[data.len - 1] == '\r'))
>                         data.len--;
> @@ -286,8 +294,6 @@ int get_common_dir_noenv(struct strbuf *sb, const char *gitdir)
>                 strbuf_addbuf(&path, &data);
>                 strbuf_add_real_path(sb, path.buf);
>                 ret = 1;
> -       } else {
> -               strbuf_addstr(sb, gitdir);
>         }
>
>         strbuf_release(&data);
> --
> 2.20.1
>


-- 
Duy

  parent reply	other threads:[~2019-02-21 10:51 UTC|newest]

Thread overview: 27+ 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 ` [PATCH 1/2] worktree: fix worktree add race Michal Suchanek
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 [this message]
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

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

  List information: http://vger.kernel.org/majordomo-info.html

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=CACsJy8AWezO7TFq8ne1a2pSAJZoc6oYqnNNxmVW_FkA9--ntbQ@mail.gmail.com \
    --to=pclouds@gmail.com \
    --cc=git@vger.kernel.org \
    --cc=gitster@pobox.com \
    --cc=mcalabkova@suse.cz \
    --cc=msuchanek@suse.de \
    --cc=sunshine@sunshineco.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
Code repositories for project(s) associated with this public inbox

	https://80x24.org/mirrors/git.git

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).