[lvm-devel] LVM2/lib/metadata metadata.h thin_manip.c
zkabelac at sourceware.org
zkabelac at sourceware.org
Mon Oct 3 18:39:18 UTC 2011
CVSROOT: /cvs/lvm2
Module name: LVM2
Changes by: zkabelac at sourceware.org 2011-10-03 18:39:18
Modified files:
lib/metadata : metadata.h thin_manip.c
Log message:
Add simple function for lookup of some free device_id
Initial simple implementation for finding some free device_id.
Patches:
http://sourceware.org/cgi-bin/cvsweb.cgi/LVM2/lib/metadata/metadata.h.diff?cvsroot=lvm2&r1=1.256&r2=1.257
http://sourceware.org/cgi-bin/cvsweb.cgi/LVM2/lib/metadata/thin_manip.c.diff?cvsroot=lvm2&r1=1.4&r2=1.5
--- LVM2/lib/metadata/metadata.h 2011/09/09 01:15:18 1.256
+++ LVM2/lib/metadata/metadata.h 2011/10/03 18:39:17 1.257
@@ -374,6 +374,9 @@
/* Find pool LV segment given a thin pool data or metadata segment. */
struct lv_segment *find_pool_seg(const struct lv_segment *seg);
+/* Find some unused device_id for thin pool LV segment. */
+uint32_t get_free_pool_device_id(struct lv_segment *thin_pool_seg);
+
/*
* Remove a dev_dir if present.
*/
--- LVM2/lib/metadata/thin_manip.c 2011/09/09 01:15:18 1.4
+++ LVM2/lib/metadata/thin_manip.c 2011/10/03 18:39:17 1.5
@@ -80,3 +80,40 @@
return pool_seg;
}
+
+/*
+ * Find a free device_id for given thin_pool segment.
+ *
+ * \return
+ * Free device id, or 0 if free device_id is not found.
+ *
+ * FIXME: Improve naive search and keep the value cached
+ * and updated during VG lifetime (so no const for lv_segment)
+ */
+uint32_t get_free_pool_device_id(struct lv_segment *thin_pool_seg)
+{
+ uint32_t dev_id, max_id = 0;
+ struct dm_list *h;
+
+ if (!seg_is_thin_pool(thin_pool_seg)) {
+ log_error("Segment in %s is not a thin pool segment.",
+ pool_seg->lv->name);
+ return 0;
+ }
+
+ dm_list_iterate(h, &thin_pool_seg->lv->segs_using_this_lv) {
+ dev_id = dm_list_item(h, struct seg_list)->seg->device_id;
+ if (dev_id > max_id)
+ max_id = dev_id;
+ }
+
+ if (++max_id >= (1 << 24)) {
+ // FIXME: try to find empty holes....
+ log_error("Free device_id exhausted...");
+ return 0;
+ }
+
+ log_debug("Found free pool device_id %u.", max_id);
+
+ return max_id;
+}
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