[lvm-devel] LVM2/lib/filters filter-mpath.c filter-mpath.h

[mbroz at sourceware.org]

CVSROOT:	/cvs/lvm2
Module name:	LVM2
Changes by:	mbroz at sourceware.org	2011-11-11 15:24:48

Added files:
	lib/filters    : filter-mpath.c filter-mpath.h 

Log message:
	And now add files for real.

Patches:
http://sourceware.org/cgi-bin/cvsweb.cgi/LVM2/lib/filters/filter-mpath.c.diff?cvsroot=lvm2&r1=NONE&r2=1.1
http://sourceware.org/cgi-bin/cvsweb.cgi/LVM2/lib/filters/filter-mpath.h.diff?cvsroot=lvm2&r1=NONE&r2=1.1

/cvs/lvm2/LVM2/lib/filters/filter-mpath.c,v  -->  standard output
revision 1.1
--- LVM2/lib/filters/filter-mpath.c
+++ -	2011-11-11 15:24:48.594061000 +0000
@@ -0,0 +1,190 @@
+/*
+ * Copyright (C) 2011 Red Hat, Inc. All rights reserved.
+ *
+ * This file is part of LVM2.
+ *
+ * This copyrighted material is made available to anyone wishing to use,
+ * modify, copy, or redistribute it subject to the terms and conditions
+ * of the GNU Lesser General Public License v.2.1.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#include "lib.h"
+#include "filter.h"
+#include "filter-mpath.h"
+#include "activate.h"
+
+#ifdef linux
+#include <dirent.h>
+
+#define MPATH_PREFIX "mpath-"
+
+static const char *get_sysfs_name(struct device *dev)
+{
+	const char *name;
+
+	name = strrchr(dev_name(dev), '/');
+	if (!name)
+		return NULL;
+	name++;
+
+	if (!*name)
+		return NULL;
+
+	return name;
+}
+
+static int get_sysfs_string(const char *path, char *buffer, int max_size)
+{
+	FILE *fp;
+	int r = 0;
+
+	if (!(fp = fopen(path, "r")))
+		return_0;
+
+	if (!fgets(buffer, max_size, fp))
+		stack;
+	else
+		r = 1;
+
+	if (fclose(fp))
+		stack;
+
+	return r;
+}
+
+static int get_sysfs_get_major_minor(const char *sysfs_dir, const char *kname, int *major, int *minor)
+{
+	char path[PATH_MAX], buffer[64];
+
+	if (snprintf(path, sizeof(path), "%s/block/%s/dev", sysfs_dir, kname) < 0)
+		return_0;
+
+	if (!get_sysfs_string(path, buffer, sizeof(buffer)))
+		return 0;
+
+	if (sscanf(buffer, "%d:%d", major, minor) != 2)
+		return 0;
+
+	return 1;
+}
+
+static int get_parent_mpath(const char *dir, char *name, int max_size)
+{
+	struct dirent *d;
+	DIR *dr;
+	int r = 0;
+
+	if (!(dr = opendir(dir)))
+		return_0;
+
+	*name = '\0';
+	while ((d = readdir(dr))) {
+		if (!strcmp(d->d_name, ".") || !strcmp(d->d_name, ".."))
+			continue;
+
+		/* There should be only one holder if it is multipath */
+		if (*name) {
+			r = 0;
+			break;
+		}
+
+		strncpy(name, d->d_name, max_size);
+		r = 1;
+	}
+
+	if (closedir(dr))
+		stack;
+
+	return r;
+}
+
+static int dev_is_mpath(struct dev_filter *f, struct device *dev)
+{
+	const char *name;
+	char path[PATH_MAX+1];
+	char parent_name[PATH_MAX+1];
+	struct stat info;
+	const char *sysfs_dir = f->private;
+	int major, minor, r;
+
+	/* Limit this filter only to SCSI devices */
+	if (!major_is_scsi_device(MAJOR(dev->dev)))
+		return 0;
+
+	name = get_sysfs_name(dev);
+	if (!name)
+		return_0;
+
+	r = dm_snprintf(path, PATH_MAX, "%s/block/%s/holders", sysfs_dir, name);
+	if (r < 0)
+		return_0;
+
+	/* also will filter out partitions */
+	if (stat(path, &info) == -1 || !S_ISDIR(info.st_mode))
+		return 0;
+
+	if (!get_parent_mpath(path, parent_name, PATH_MAX))
+		return 0;
+
+	if (!get_sysfs_get_major_minor(sysfs_dir, parent_name, &major, &minor))
+		return 0;
+
+	if (major != dm_major())
+		return 0;
+
+	return lvm_dm_prefix_check(sysfs_dir, major, minor, MPATH_PREFIX);
+}
+
+static int _ignore_mpath(struct dev_filter *f, struct device *dev)
+{
+	if (dev_is_mpath(f, dev) == 1) {
+		log_debug("%s: Skipping mpath component device", dev_name(dev));
+		return 0;
+	}
+
+	return 1;
+}
+
+static void _destroy(struct dev_filter *f)
+{
+	if (f->use_count)
+		log_error(INTERNAL_ERROR "Destroying mpath filter while in use %u times.", f->use_count);
+
+	dm_free(f->private);
+	dm_free(f);
+}
+
+struct dev_filter *mpath_filter_create(const char *sysfs_dir)
+{
+	struct dev_filter *f;
+
+	if (!*sysfs_dir) {
+		log_verbose("No proc filesystem found: skipping multipath filter");
+		return NULL;
+	}
+
+	if (!(f = dm_malloc(sizeof(*f)))) {
+		log_error("mpath filter allocation failed");
+		return NULL;
+	}
+
+	f->passes_filter = _ignore_mpath;
+	f->destroy = _destroy;
+	f->use_count = 0;
+	f->private = dm_strdup(sysfs_dir);
+
+	return f;
+}
+
+#else
+
+struct dev_filter *mpath_filter_create(const char *sysfs_dir __attribute__((unused)))
+{
+	return NULL;
+}
+
+#endif
/cvs/lvm2/LVM2/lib/filters/filter-mpath.h,v  -->  standard output
revision 1.1
--- LVM2/lib/filters/filter-mpath.h
+++ -	2011-11-11 15:24:48.717851000 +0000
@@ -0,0 +1,23 @@
+/*
+ * Copyright (C) 2011 Red Hat, Inc. All rights reserved.
+ *
+ * This file is part of LVM2.
+ *
+ * This copyrighted material is made available to anyone wishing to use,
+ * modify, copy, or redistribute it subject to the terms and conditions
+ * of the GNU Lesser General Public License v.2.1.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifndef _LVM_FILTER_MPATH_H
+#define _LVM_FILTER_MPATH_H
+
+#include "dev-cache.h"
+
+struct dev_filter *mpath_filter_create(const char *sysfs_dir);
+
+#endif
+