public inbox for git@vger.kernel.org 
 help / color / mirror / Atom feed
From: Junio C Hamano <gitster@pobox•com>
To: Stefan Beller <sbeller@google•com>
Cc: ronniesahlberg@gmail•com, mhagger@alum•mit.edu,
	jrnieder@gmail•com, sunshine@sunshineco•com, git@vger•kernel.org,
	Ronnie Sahlberg <sahlberg@google•com>
Subject: Re: [PATCHv3 4/6] receive-pack.c: use a single ref_transaction for atomic pushes
Date: Wed, 17 Dec 2014 15:26:14 -0800	[thread overview]
Message-ID: <xmqqa92l97u1.fsf@gitster.dls.corp.google.com> (raw)
In-Reply-To: <1418841177-12152-5-git-send-email-sbeller@google.com> (Stefan Beller's message of "Wed, 17 Dec 2014 10:32:55 -0800")

Stefan Beller <sbeller@google•com> writes:

> @@ -1086,8 +1100,25 @@ static void execute_commands(struct command *commands,
>  
>  		if (cmd->skip_update)
>  			continue;
> -
> +		if (!use_atomic) {
> +			transaction = ref_transaction_begin(&err);
> +			if (!transaction) {
> +				rp_error("%s", err.buf);
> +				strbuf_release(&err);
> +				cmd->error_string = "failed to start transaction";
> +				return;
> +			}
> +		}
>  		cmd->error_string = update(cmd, si);
> +		if (!use_atomic)
> +			if (ref_transaction_commit(transaction, &err)) {
> +				ref_transaction_free(transaction);
> +				rp_error("%s", err.buf);
> +				strbuf_release(&err);
> +				cmd->error_string = "failed to update ref";
> +				return;
> +			}

Hmm, should the code even attempt to commit if update() returned a
non NULL, signaling a failure?

Or would we want to do this instead?

	if (cmd->error_string)
        	goto transaction_abort;
	else if (!use_atomic) {
		if (ref_transaction_commit(...)) {
			...
                        cmd->error_string = "...";
                        return;
        	}
	}

and then ...

>  		if (shallow_update && !cmd->error_string &&
>  		    si->shallow_ref[cmd->index]) {
>  			error("BUG: connectivity check has not been run on ref %s",
> @@ -1096,10 +1127,32 @@ static void execute_commands(struct command *commands,
>  		}
>  	}
>  
> +	if (use_atomic) {
> +		/*
> +		 * update(...) may abort early (i.e. because the hook refused to
> +		 * update that ref) which then doesn't even record a transaction
> +		 * regarding that ref. Make sure all commands are without error
> +		 * and then commit atomically.
> +		 */
> +		for (cmd = commands; cmd; cmd = cmd->next)
> +			if (cmd->error_string)
> +				break;
> +		if (cmd) {
> +			for (cmd = commands; cmd; cmd = cmd->next)
> +				if (!cmd->error_string)
> +					cmd->error_string = "atomic push failure";
> +		} else if (ref_transaction_commit(transaction, &err)) {
> +			rp_error("%s", err.buf);
> +			for (cmd = commands; cmd; cmd = cmd->next)
> +				cmd->error_string = err.buf;
> +		}

... have the label to jump to here:

	transaction_abort:

> +		ref_transaction_free(transaction);

I was confused by the fact that you did not have any call to
transaction-abort, until I realized that there is no such API
function and ref_transaction_free() serves that "don't commit,
roll it back" purpose.

> +	}
>  	if (shallow_update && !checked_connectivity)
>  		error("BUG: run 'git fsck' for safety.\n"
>  		      "If there are errors, try to remove "
>  		      "the reported refs above");
> +	strbuf_release(&err);
>  }
>  
>  static struct command **queue_command(struct command **tail,

  reply	other threads:[~2014-12-17 23:26 UTC|newest]

Thread overview: 56+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-12-15 19:56 [PATCH 0/5] Add a flag to push atomically Stefan Beller
2014-12-15 19:56 ` [PATCH 1/5] receive-pack.c: add protocol support to negotiate atomic-push Stefan Beller
2014-12-15 20:53   ` Junio C Hamano
2014-12-15 22:30     ` Stefan Beller
2014-12-15 19:56 ` [PATCH 2/5] send-pack.c: add an --atomic-push command line argument Stefan Beller
2014-12-15 21:01   ` Junio C Hamano
2014-12-15 19:56 ` [PATCH 3/5] receive-pack.c: use a single ref_transaction for atomic pushes Stefan Beller
2014-12-15 21:37   ` Junio C Hamano
2014-12-15 19:56 ` [PATCH 4/5] push.c: add an --atomic-push argument Stefan Beller
2014-12-15 21:50   ` Junio C Hamano
2014-12-15 19:56 ` [PATCH 5/5] t5543-atomic-push.sh: add basic tests for atomic pushes Stefan Beller
2014-12-15 22:29   ` Junio C Hamano
2014-12-15 22:33 ` [PATCH 0/5] Add a flag to push atomically Junio C Hamano
2014-12-16 18:49   ` [PATCHv2 1/6] receive-pack.c: add protocol support to negotiate atomic-push Stefan Beller
2014-12-16 18:49     ` [PATCHv2 2/6] send-pack: Invert the return value of ref_update_to_be_sent Stefan Beller
2014-12-16 19:14       ` Junio C Hamano
2014-12-16 18:49     ` [PATCHv2 3/6] send-pack.c: add --atomic command line argument Stefan Beller
2014-12-16 19:31       ` Junio C Hamano
2014-12-16 18:49     ` [PATCHv2 4/6] receive-pack.c: use a single ref_transaction for atomic pushes Stefan Beller
2014-12-16 19:29       ` Eric Sunshine
2014-12-16 20:30         ` Eric Sunshine
2014-12-16 19:35       ` Junio C Hamano
2014-12-16 18:49     ` [PATCHv2 5/6] push.c: add an --atomic-push argument Stefan Beller
2014-12-16 19:33       ` Eric Sunshine
2014-12-16 20:43         ` Junio C Hamano
2014-12-16 19:36       ` Junio C Hamano
2014-12-16 18:49     ` [PATCHv2 6/6] t5543-atomic-push.sh: add basic tests for atomic pushes Stefan Beller
2014-12-16 19:14       ` [PATCH] receive-pack: refuse all commands if one fails in atomic mode Stefan Beller
2014-12-16 20:32         ` Junio C Hamano
2014-12-16 19:37       ` [PATCHv2 6/6] t5543-atomic-push.sh: add basic tests for atomic pushes Eric Sunshine
2014-12-16 19:46       ` Junio C Hamano
2014-12-16 19:57         ` Stefan Beller
2014-12-16 20:46           ` Junio C Hamano
2014-12-16 20:51             ` Stefan Beller
2014-12-16 20:30       ` Junio C Hamano
2014-12-16 20:36         ` Stefan Beller
2014-12-16 19:05     ` [PATCHv2 1/6] receive-pack.c: add protocol support to negotiate atomic-push Junio C Hamano
2014-12-17 18:32   ` [PATCHv3 0/6] atomic pushes Stefan Beller
2014-12-17 18:32     ` [PATCHv3 1/6] receive-pack.c: add protocol support to negotiate atomic Stefan Beller
2014-12-19  1:05       ` Eric Sunshine
2014-12-17 18:32     ` [PATCHv3 2/6] send-pack: Rename ref_update_to_be_sent to check_to_send_update Stefan Beller
2014-12-17 22:53       ` Junio C Hamano
2014-12-17 18:32     ` [PATCHv3 3/6] send-pack.c: add --atomic command line argument Stefan Beller
2014-12-17 23:14       ` Junio C Hamano
2014-12-19  1:22       ` Eric Sunshine
2014-12-17 18:32     ` [PATCHv3 4/6] receive-pack.c: use a single ref_transaction for atomic pushes Stefan Beller
2014-12-17 23:26       ` Junio C Hamano [this message]
2014-12-17 23:58         ` Stefan Beller
2014-12-18 17:02           ` Junio C Hamano
2014-12-18 17:45             ` [PATCHv4 " Stefan Beller
2014-12-18 22:26               ` Eric Sunshine
2014-12-19  0:22                 ` [PATCHv5 " Stefan Beller
2014-12-19 10:14                   ` Eric Sunshine
2014-12-17 18:32     ` [PATCHv3 5/6] push.c: add an --atomic argument Stefan Beller
2014-12-19  1:29       ` Eric Sunshine
2014-12-17 18:32     ` [PATCHv3 6/6] t5543-atomic-push.sh: add basic tests for atomic pushes Stefan Beller

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

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

  git send-email \
    --in-reply-to=xmqqa92l97u1.fsf@gitster.dls.corp.google.com \
    --to=gitster@pobox$(echo .)com \
    --cc=git@vger$(echo .)kernel.org \
    --cc=jrnieder@gmail$(echo .)com \
    --cc=mhagger@alum$(echo .)mit.edu \
    --cc=ronniesahlberg@gmail$(echo .)com \
    --cc=sahlberg@google$(echo .)com \
    --cc=sbeller@google$(echo .)com \
    --cc=sunshine@sunshineco$(echo .)com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox