[PATCH] ctdb-daemon: Handle out-of-memory when setting recovery lock file

[Michael Adam]

reviewed by me (although the "and" in the commit message
would argue for splitting the patch in two..)- pushing

On 2015-01-07 at 18:14 +1100, Martin Schwenke wrote:
> Review and push appreciated, thanks.
> 
> peace & happiness,
> martin

> >From 9e9c387a87e36843acb5ad08c343ca7368190378 Mon Sep 17 00:00:00 2001
> From: Martin Schwenke <martin at meltin.net>
> Date: Tue, 9 Dec 2014 13:40:23 +1100
> Subject: [PATCH] ctdb-daemon: Handle out-of-memory when setting recovery lock
>  file
> 
> Log a message when the reclock file actually changes and avoid a
> memory allocation when it doesn't change.
> 
> Signed-off-by: Martin Schwenke <martin at meltin.net>
> ---
>  ctdb/server/ctdb_control.c | 34 ++++++++++++++++++++++++++--------
>  1 file changed, 26 insertions(+), 8 deletions(-)
> 
> diff --git a/ctdb/server/ctdb_control.c b/ctdb/server/ctdb_control.c
> index 49bc986..9d835e8 100644
> --- a/ctdb/server/ctdb_control.c
> +++ b/ctdb/server/ctdb_control.c
> @@ -519,17 +519,35 @@ static int32_t ctdb_control_dispatch(struct ctdb_context *ctdb,
>  			outdata->dsize = strlen(ctdb->recovery_lock_file) + 1;
>  		}
>  		return 0;
> -	case CTDB_CONTROL_SET_RECLOCK_FILE:
> -		ctdb->tunable.verify_recovery_lock = 0;
> -		if (ctdb->recovery_lock_file != NULL) {
> -			talloc_free(ctdb->recovery_lock_file);
> -			ctdb->recovery_lock_file = NULL;
> +	case CTDB_CONTROL_SET_RECLOCK_FILE: {
> +		char *t;
> +
> +		if (indata.dsize == 0) {
> +			TALLOC_FREE(ctdb->recovery_lock_file);
> +			return 0;
> +		}
> +
> +		/* Return silent success if unchanged.  Recovery
> +		 * master updates all nodes on each recovery - we
> +		 * don't need the extra memory allocation or log
> +		 * message each time. */
> +		if (strcmp(discard_const(indata.dptr),
> +			   ctdb->recovery_lock_file) == 0) {
> +			return 0;
>  		}
> -		if (indata.dsize > 0) {
> -			ctdb->recovery_lock_file = talloc_strdup(ctdb, discard_const(indata.dptr));
> -			ctdb->tunable.verify_recovery_lock = 1;
> +
> +		t = talloc_strdup(ctdb, discard_const(indata.dptr));
> +		if (t == NULL) {
> +			DEBUG(DEBUG_ERR, ("Out of memory in SET_RECLOCK_FILE\n"));
> +			return -1;
>  		}
> +
> +		talloc_free(ctdb->recovery_lock_file);
> +		ctdb->recovery_lock_file = t;
> +		DEBUG(DEBUG_NOTICE, ("Updated recovery lock file to %s\n", t));
> +
>  		return 0;
> +	}
>  
>  	case CTDB_CONTROL_STOP_NODE:
>  		CHECK_CONTROL_DATA_SIZE(0);
> -- 
> 2.1.4
> 

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