[linux-lvm] LVM1 on top of DRBD

[Heinz J . Mauelshagen]

On Wed, Aug 20, 2003 at 04:49:47PM +0200, Joachim Banzhaf wrote:
> Am Mittwoch, 20. August 2003 15:31 schrieb Heinz J . Mauelshagen:
> > On Wed, Aug 20, 2003 at 01:54:36PM +0200, Joachim Banzhaf wrote:
> > > Am Mittwoch, 20. August 2003 12:46 schrieb Heinz J . Mauelshagen:
> 
> > > > DRBD devices are just some other "local" ones for it.
> > >
> > > OK, but as i stated, I used them that way. LVM1 just seems to use the
> > > lower level devices drbd works on instead. That's what's bothering me.
> >
> > Ah, missed that point :(
> > LVM2 is your better option because it supports device name filters
> > in a config file rather than hard-coded ones.
> 
> Well, I guess I have to - and hope for the best. Since I thought I had that 
> filter implemented in LVM1 (see attached patch) and that did not work, my 
> expectations aren't too high...

Well, what you implemented is a subset of what the LVM2 device name filters,
which are regular expression based can do for you :)

> 
> > > Again, to clear the ground: Should it be possible at all to use pv's on
> > > top of drbd devices or am I forced to use drbd devices on top of lv's and
> > > loose things like online resize feature?
> > >
> > > Have you - or anybody reading the list - ever sucessfully used that
> > > scenario?
> >
> > I don't. List ?
> 
> 
> 
> 

> --- LVM/1.0.6/tools/lib/lvm_dir_cache.c	2002-04-26 09:52:49.000000000 +0200
> +++ LVM/1.0.6/tools/lib/lvm_dir_cache.with.ignore.c	2003-08-20 04:05:46.000000000 +0200
> @@ -45,6 +45,7 @@
>   *    07/07/2001 - realloc now doubles the size of the cache [JT]
>   *    17/12/2001 - make it find loop devices again [HM]
>   *    01/22/2002 - fix broken whole device support [HM]
> + *    08/18/2003 - add ignore devices feature for lvm on drbd [jbanzhaf at ngi.de]
>   *
>   */
>  
> @@ -52,6 +53,14 @@
>  #include <liblvm.h>
>  
>  
> +#define IGNOREDFILE "/etc/lvmconf/ignored_devices"
> +
> +typedef struct ignored_dev {
> +	char *name;
> +	struct ignored_dev *next;
> +} ignored_dev_t;
> +
> +
>  static void _scan_partitions();
>  static void _scan_devs(int);
>  static int _add(char *directory, char *devname);
> @@ -59,12 +68,17 @@
>  static int _alloc();
>  static int _is_present(dev_t rdev);
>  static void _collapse_slashes(char *str);
> -
> +static void _read_ignored();
> +static void _free_ignored(ignored_dev_t **node);
> +static int _ignore(char *str);
>  
>  static dir_cache_t *_dir_cache;
>  static int _cache_size;
>  static int _array_size;
>  
> +static ignored_dev_t *_ignored_head = NULL;
> +
> +
>  /* devices *not* showing up in /proc/partitions must be scanned anyway */
>  static char *_noprocdir[] = {
>  	LVM_DIR_PREFIX "loop",
> @@ -99,11 +113,13 @@
>  	}
>  
>  	if (!_dir_cache) {
> +		_read_ignored();
>  		_scan_partitions();
>  		if(!_cache_size)
>  			_scan_devs( TRUE);
>  		else
>  			_scan_devs( FALSE);
> +		_free_ignored(&_ignored_head);
>  	}
>  
>  	*dir_cache_ptr = _dir_cache;
> @@ -255,6 +271,9 @@
>  
>  	debug_enter("lvm_add_dir_cache -- CALLED with %s\n", devpath);
>  
> +	if (_ignore(devpath))
> +		goto out;
> +
>  	if (stat(devpath, &stat_b) == -1)
>  		goto out;
>  
> @@ -348,3 +367,78 @@
>  
>  	*str = *ptr;
>  }
> +
> +static void _add_ignored(char *line, ignored_dev_t ***list_tail)
> +{
> +	int len;
> +	int add = 1;
> +	ignored_dev_t *new_node;
> +	
> +	len = strlen(line);
> +	if (line[len - 1] == '\n') {
> +		line[len - 1] = '\0';
> +		len--;
> +	}
> +	
> +	debug_enter("_add_ignored -- CALLED with %s\n", line);
> +	
> +	new_node = (ignored_dev_t *)malloc(sizeof(ignored_dev_t));
> +	if (new_node) {
> +		new_node->name = strdup(line);
> +		if (new_node->name) {
> +			new_node->next = NULL;
> +			**list_tail = new_node;
> +			*list_tail = &new_node->next;
> +		} else {
> +			free(new_node);
> +			add = 0;
> +		}
> +	} else {
> +		add = 0;
> +	}
> +	
> +	debug_leave("_add_ignored '%s' -- LEAVING with ret: %s\n", line, add ? "OK" : "ERROR");
> +}
> +
> +static void _read_ignored()
> +{
> +	FILE	       *f;
> +	char	        line[NAME_LEN];
> +	ignored_dev_t **list_tail = &_ignored_head;
> +	
> +	if ( (f=fopen(IGNOREDFILE, "r")) != NULL ) {
> +		while(fgets(line, sizeof(line), f)) {
> +			if (line[0] != '\0' && line[0] != '\n' && line[0] != '#') {
> +				_add_ignored(line, &list_tail);
> +			}
> +		}	
> +		fclose(f);
> +	}
> +}
> +
> +static void _free_ignored(ignored_dev_t **curr)
> +{
> +	if( *curr )
> +	{
> +		_free_ignored(&(*curr)->next);
> +		free((*curr)->name);
> +		free(*curr);
> +		*curr = NULL;
> +	}	
> +}
> +
> +static int _ignore(char *str)
> +{
> +	int rc = 0;
> +	ignored_dev_t *curr = _ignored_head;
> +
> +	while (curr) {
> +		if (!strcmp(str, curr->name)) {
> +			rc = 1;
> +			break;
> +		}
> +		curr = curr->next;
> +	}
> +	return rc;
> +}
> +


-- 

Regards,
Heinz    -- The LVM Guy --

*** Software bugs are stupid.
    Nevertheless it needs not so stupid people to solve them ***

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Heinz Mauelshagen                                 Sistina Software Inc.
Senior Consultant/Developer                       Am Sonnenhang 11
                                                  56242 Marienrachdorf
                                                  Germany
Mauelshagen at Sistina.com                           +49 2626 141200
                                                       FAX 924446
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