Fix for Debian Bug#574863: boot failure with lvm2 and snapshot volumes

@@ -420,9 +420,11 @@
 	  /* And add all the lvs to the volume group. */
 	  while (1)
 	    {
-	      int s;
+	      int s, skip_lv = 0, status_visible = 0;
 	      struct grub_lvm_lv *lv;
 	      struct grub_lvm_segment *seg;
+	      char *status = NULL, *status_end = NULL;
+	      grub_size_t status_len = 0;
 
 	      while (grub_isspace (*p))
 		p++;

@@ -431,6 +433,8 @@
 		break;
 
 	      lv = grub_malloc (sizeof (*lv));
+		skip_lv = 0; /*Flag to skip snapshots */
+		status_visible = 0; /*Flag to skip non-visible LV's */
 
 	      q = p;
 	      while (*q != ' ')

@@ -445,6 +449,25 @@
 
 	      lv->size = 0;
 
+		/* read LV status and ignore ones not listed as "VISIBLE" */
+		p = grub_strstr (p, "status = ");
+		if (p == NULL)
+			goto lvs_fail;
+		status_end = grub_strchr(p, ']');
+		if (status_end == NULL)
+			goto lvs_fail;
+		status_len = (status_end - p) + 1;
+		status = grub_malloc(status_len + 1);
+		if (status == NULL)
+			goto lvs_fail;
+		grub_memcpy(status, p, status_len);
+		status[status_len] = '\0';
+		if (grub_strstr(status, "VISIBLE") != NULL)
+			status_visible = 1;
+		grub_free(status);
+		if (!status_visible)
+			goto lv_parsed;  /* don't bother parsing this one */
+
 	      lv->segment_count = grub_lvm_getvalue (&p, "segment_count = ");
 	      if (p == NULL)
 		goto lvs_fail;

@@ -465,6 +488,18 @@
 		  seg->extent_count = grub_lvm_getvalue (&p, "extent_count = ");
 		  if (p == NULL)
 		    goto lvs_segment_fail;
+
+			/* Skip LV's that have snapshot segments */
+			p = grub_strstr (p, "type = ");
+			if (p == NULL)
+				goto lvs_segment_fail;
+			p += sizeof("type = ") - 1;
+			if (!grub_strncmp(p, "\"snapshot\"", 10)) {
+				/* Found a snapshot, give up and move on */
+				skip_lv=1;
+				break;
+			}
+
 		  seg->stripe_count = grub_lvm_getvalue (&p, "stripe_count = ");
 		  if (p == NULL)
 		    goto lvs_segment_fail;

@@ -531,12 +566,19 @@
 		  goto fail4;
 		}
 
+	    lv_parsed: /* all done with parsing this LV, seek to the end */
 	      if (p != NULL)
 		p = grub_strchr (p, '}');
 	      if (p == NULL)
 		goto lvs_fail;
 	      p += 3;
 
+		if (skip_lv || ! status_visible) {
+			grub_free (lv->name);
+			grub_free (lv);
+			continue;
+		}
+
 	      lv->number = lv_count++;
 	      lv->vg = vg;
 	      lv->next = vg->lvs;

@@ -420,9 +420,11 @@
 	  /* And add all the lvs to the volume group. */
 	  while (1)
 	    {
-	      int s;
+	      int s, skip_lv = 0, status_visible = 0;
 	      struct grub_lvm_lv *lv;
 	      struct grub_lvm_segment *seg;
+	      char *status = NULL, *status_end = NULL;
+	      grub_size_t status_len = 0;
 
 	      while (grub_isspace (*p))
 		p++;

@@ -431,6 +433,8 @@
 		break;
 
 	      lv = grub_malloc (sizeof (*lv));
+	      skip_lv = 0; /*Flag to skip snapshots */
+	      status_visible = 0; /*Flag to skip non-visible LV's */
 
 	      q = p;
 	      while (*q != ' ')

@@ -445,6 +449,25 @@
 
 	      lv->size = 0;
 
+	      /* read LV status and ignore ones not listed as "VISIBLE" */
+	      p = grub_strstr (p, "status = ");
+	      if (p == NULL)
+	        goto lvs_fail;
+	      status_end = grub_strchr (p, ']');
+	      if (status_end == NULL)
+	        goto lvs_fail;
+	      status_len = (status_end - p) + 1;
+	      status = grub_malloc (status_len + 1);
+	      if (status == NULL)
+	        goto lvs_fail;
+	      grub_memcpy (status, p, status_len);
+	      status[status_len] = '\0';
+	      if (grub_strstr (status, "VISIBLE") != NULL)
+	        status_visible = 1;
+	      grub_free (status);
+	      if (!status_visible)
+	        goto lv_parsed;  /* don't bother parsing this one */
+
 	      lv->segment_count = grub_lvm_getvalue (&p, "segment_count = ");
 	      if (p == NULL)
 		goto lvs_fail;

@@ -465,6 +488,19 @@
 		  seg->extent_count = grub_lvm_getvalue (&p, "extent_count = ");
 		  if (p == NULL)
 		    goto lvs_segment_fail;
+
+		  /* Skip LV's that have snapshot segments */
+		  p = grub_strstr (p, "type = ");
+		  if (p == NULL)
+		    goto lvs_segment_fail;
+		  p += sizeof ("type = ") - 1;
+		  if (!grub_strncmp (p, "\"snapshot\"", 10))
+		    {
+		      /* Found a snapshot, give up and move on */
+		      skip_lv=1;
+		      break;
+		    }
+
 		  seg->stripe_count = grub_lvm_getvalue (&p, "stripe_count = ");
 		  if (p == NULL)
 		    goto lvs_segment_fail;

@@ -531,12 +567,20 @@
 		  goto fail4;
 		}
 
+	    lv_parsed: /* all done with parsing this LV, seek to the end */
 	      if (p != NULL)
 		p = grub_strchr (p, '}');
 	      if (p == NULL)
 		goto lvs_fail;
 	      p += 3;
 
+	      if (skip_lv || ! status_visible)
+	        {
+	          grub_free (lv->name);
+	          grub_free (lv);
+	          continue;
+	        }
+
 	      lv->number = lv_count++;
 	      lv->vg = vg;
 	      lv->next = vg->lvs;

@@ -46,6 +46,52 @@ grub_lvm_getvalue (char **p, char *str)
 }
 
 static int
+grub_lvm_checkvalue (char **p, char *str, char *tmpl)
+{
+  int tmpllen = grub_strlen (tmpl);
+  *p = grub_strstr (*p, str);
+  if (! *p)
+    return 0;
+  *p += grub_strlen (str);
+  if (**p != '"')
+    return 0;
+  return (grub_memcmp (*p + 1, tmpl, tmpllen) == 0 && (*p)[tmpllen + 1] == '"');
+}
+
+static int
+grub_lvm_check_flag (char *p, char *str, char *flag)
+{
+  int len_str = grub_strlen (str), len_flag = grub_strlen (flag);
+  while (1)
+    {
+      char *q;
+      p = grub_strstr (p, str);
+      if (! p)
+	return 0;
+      p += len_str;
+      if (grub_memcmp (p, " = [", sizeof (" = [") - 1) != 0)
+	continue;
+      q = p + sizeof (" = [") - 1;
+      while (1)
+	{
+	  while (grub_isspace (*q))
+	    q++;
+	  if (*q != '"')
+	    return 0;
+	  q++;
+	  if (grub_memcmp (q, flag, len_flag) == 0 && q[len_flag] == '"')
+	    return 1;
+	  while (*q != '"')
+	    q++;
+	  q++;
+	  if (*q == ']')
+	    return 0;
+	  q++;
+	}
+    }
+}
+
+static int
 grub_lvm_iterate (int (*hook) (const char *name))
 {
   struct grub_lvm_vg *vg;

@@ -421,6 +467,7 @@ grub_lvm_scan_device (const char *name)
 	  while (1)
 	    {
 	      int s;
+	      int skip_lv = 0;
 	      struct grub_lvm_lv *lv;
 	      struct grub_lvm_segment *seg;
 

@@ -445,6 +492,12 @@ grub_lvm_scan_device (const char *name)
 
 	      lv->size = 0;
 
+	      if (!grub_lvm_check_flag (p, "status", "VISIBLE"))
+		{
+		  skip_lv = 1;
+		  goto lv_parsed;
+		}
+
 	      lv->segment_count = grub_lvm_getvalue (&p, "segment_count = ");
 	      if (p == NULL)
 		goto lvs_fail;

@@ -465,6 +518,14 @@ grub_lvm_scan_device (const char *name)
 		  seg->extent_count = grub_lvm_getvalue (&p, "extent_count = ");
 		  if (p == NULL)
 		    goto lvs_segment_fail;
+
+		  if (grub_lvm_checkvalue (&p, "type = ", "snapshot"))
+		    {
+		      /* Found a snapshot, give up and move on. */
+		      skip_lv = 1;
+		      break;
+		    }
+
 		  seg->stripe_count = grub_lvm_getvalue (&p, "stripe_count = ");
 		  if (p == NULL)
 		    goto lvs_segment_fail;

@@ -531,12 +592,20 @@ grub_lvm_scan_device (const char *name)
 		  goto fail4;
 		}
 
+	    lv_parsed:
 	      if (p != NULL)
 		p = grub_strchr (p, '}');
 	      if (p == NULL)
 		goto lvs_fail;
 	      p += 3;
 
+	      if (skip_lv)
+		{
+		  grub_free (lv->name);
+		  grub_free (lv);
+		  continue;
+		}
+
 	      lv->number = lv_count++;
 	      lv->vg = vg;
 	      lv->next = vg->lvs;