toollib: process different devices for duplicate pvsdev-dct-pvdup-split2

This hacks the lvmcache before processing the PV so that
the PV appears to be from the duplicate devices instead
of pv->dev.  lvmcache state is returned to the way it
was after process_single.

With two duplicate devices, loop0 and loop3:

  # pvs
  Found duplicate PV XhLbpVo0hmuwrMQLjfxuAvPFUFZqD4vr: using /dev/loop3 not /dev/loop0
  PV         VG           Fmt  Attr PSize   PFree
  /dev/loop3 loopa        lvm2 a--   12.00m  12.00m

  # pvs /dev/loop3
  Found duplicate PV XhLbpVo0hmuwrMQLjfxuAvPFUFZqD4vr: using /dev/loop3 not /dev/loop0
  PV         VG    Fmt  Attr PSize  PFree
  /dev/loop3 loopa lvm2 a--  12.00m 12.00m

  # pvs /dev/loop0
  Found duplicate PV XhLbpVo0hmuwrMQLjfxuAvPFUFZqD4vr: using /dev/loop3 not /dev/loop0
  PV         VG    Fmt  Attr PSize  PFree
  /dev/loop3 loopa lvm2 a--  12.00m 12.00m

  # pvs /dev/loop0 /dev/loop3
  Found duplicate PV XhLbpVo0hmuwrMQLjfxuAvPFUFZqD4vr: using /dev/loop3 not /dev/loop0
  PV         VG    Fmt  Attr PSize  PFree
  /dev/loop0 loopa lvm2 a--  12.00m 12.00m
  /dev/loop3 loopa lvm2 a--  12.00m 12.00m

  # pvs -o+dev_size /dev/loop0 /dev/loop3
  Found duplicate PV XhLbpVo0hmuwrMQLjfxuAvPFUFZqD4vr: using /dev/loop3 not /dev/loop0
  PV         VG    Fmt  Attr PSize  PFree  DevSize
  /dev/loop0 loopa lvm2 a--  12.00m 12.00m  16.00m
  /dev/loop3 loopa lvm2 a--  12.00m 12.00m  32.00m

With three duplicate devices, loop0, loop1, loop3:

  # pvs -o+dev_size
  Found duplicate PV XhLbpVo0hmuwrMQLjfxuAvPFUFZqD4vr: using /dev/loop1 not /dev/loop0
  Found duplicate PV XhLbpVo0hmuwrMQLjfxuAvPFUFZqD4vr: using /dev/loop3 not /dev/loop1
  PV         VG           Fmt  Attr PSize   PFree   DevSize
  /dev/loop3 loopa        lvm2 a--   12.00m  12.00m  32.00m

  # pvs -o+dev_size /dev/loop3
  Found duplicate PV XhLbpVo0hmuwrMQLjfxuAvPFUFZqD4vr: using /dev/loop1 not /dev/loop0
  Found duplicate PV XhLbpVo0hmuwrMQLjfxuAvPFUFZqD4vr: using /dev/loop3 not /dev/loop1
  PV         VG    Fmt  Attr PSize  PFree  DevSize
  /dev/loop3 loopa lvm2 a--  12.00m 12.00m  32.00m

  # pvs -o+dev_size /dev/loop0
  Found duplicate PV XhLbpVo0hmuwrMQLjfxuAvPFUFZqD4vr: using /dev/loop1 not /dev/loop0
  Found duplicate PV XhLbpVo0hmuwrMQLjfxuAvPFUFZqD4vr: using /dev/loop3 not /dev/loop1
  PV         VG    Fmt  Attr PSize  PFree  DevSize
  /dev/loop3 loopa lvm2 a--  12.00m 12.00m  32.00m

  # pvs -o+dev_size /dev/loop1
  Found duplicate PV XhLbpVo0hmuwrMQLjfxuAvPFUFZqD4vr: using /dev/loop1 not /dev/loop0
  Found duplicate PV XhLbpVo0hmuwrMQLjfxuAvPFUFZqD4vr: using /dev/loop3 not /dev/loop1
  PV         VG    Fmt  Attr PSize  PFree  DevSize
  /dev/loop3 loopa lvm2 a--  12.00m 12.00m  32.00m

  # pvs -o+dev_size /dev/loop3 /dev/loop0
  Found duplicate PV XhLbpVo0hmuwrMQLjfxuAvPFUFZqD4vr: using /dev/loop1 not /dev/loop0
  Found duplicate PV XhLbpVo0hmuwrMQLjfxuAvPFUFZqD4vr: using /dev/loop3 not /dev/loop1
  PV         VG    Fmt  Attr PSize  PFree  DevSize
  /dev/loop0 loopa lvm2 a--  12.00m 12.00m  16.00m
  /dev/loop3 loopa lvm2 a--  12.00m 12.00m  32.00m

  # pvs -o+dev_size /dev/loop3 /dev/loop1
  Found duplicate PV XhLbpVo0hmuwrMQLjfxuAvPFUFZqD4vr: using /dev/loop1 not /dev/loop0
  Found duplicate PV XhLbpVo0hmuwrMQLjfxuAvPFUFZqD4vr: using /dev/loop3 not /dev/loop1
  PV         VG    Fmt  Attr PSize  PFree  DevSize
  /dev/loop1 loopa lvm2 a--  12.00m 12.00m  32.00m
  /dev/loop3 loopa lvm2 a--  12.00m 12.00m  32.00m

  # pvs -o+dev_size /dev/loop0 /dev/loop1
  Found duplicate PV XhLbpVo0hmuwrMQLjfxuAvPFUFZqD4vr: using /dev/loop1 not /dev/loop0
  Found duplicate PV XhLbpVo0hmuwrMQLjfxuAvPFUFZqD4vr: using /dev/loop3 not /dev/loop1
  PV         VG    Fmt  Attr PSize  PFree  DevSize
  /dev/loop1 loopa lvm2 a--  12.00m 12.00m  32.00m
  /dev/loop3 loopa lvm2 a--  12.00m 12.00m  32.00m

  # pvs -o+dev_size /dev/loop0 /dev/loop1 /dev/loop3
  Found duplicate PV XhLbpVo0hmuwrMQLjfxuAvPFUFZqD4vr: using /dev/loop1 not /dev/loop0
  Found duplicate PV XhLbpVo0hmuwrMQLjfxuAvPFUFZqD4vr: using /dev/loop3 not /dev/loop1
  PV         VG    Fmt  Attr PSize  PFree  DevSize
  /dev/loop0 loopa lvm2 a--  12.00m 12.00m  16.00m
  /dev/loop1 loopa lvm2 a--  12.00m 12.00m  32.00m
  /dev/loop3 loopa lvm2 a--  12.00m 12.00m  32.00m

3 files changed, 33 insertions, 4 deletions

diff --git a/lib/cache/lvmcache.c b/lib/cache/lvmcache.c
index 932b1ca33..6cdf766f3 100644
--- a/lib/cache/lvmcache.c
+++ b/lib/cache/lvmcache.c
@@ -1467,6 +1467,27 @@ int lvmcache_update_vg(struct volume_group *vg, unsigned precommitted)
 	return 1;
 }
 
+/*
+ * Replace pv->dev with dev so that dev will appear for reporting.
+ */
+
+void lvmcache_replace_dev(struct cmd_context *cmd, struct physical_volume *pv,
+			  struct device *dev)
+{
+	struct lvmcache_info *info;
+	char pvid_s[ID_LEN + 1] __attribute__((aligned(8)));
+
+	strncpy(pvid_s, (char *) &pv->id, sizeof(pvid_s) - 1);
+	pvid_s[sizeof(pvid_s) - 1] = '\0';
+
+	if (!(info = lvmcache_info_from_pvid(pvid_s, 0)))
+		return;
+
+	info->dev = dev;
+	info->label->dev = dev;
+	pv->dev = dev;
+}
+
 struct lvmcache_info *lvmcache_add(struct labeller *labeller, const char *pvid,
 				   struct device *dev,
 				   const char *vgname, const char *vgid,
diff --git a/lib/cache/lvmcache.h b/lib/cache/lvmcache.h
index d43866dca..7a049175b 100644
--- a/lib/cache/lvmcache.h
+++ b/lib/cache/lvmcache.h
@@ -157,4 +157,7 @@ unsigned lvmcache_mda_count(struct lvmcache_info *info);
 int lvmcache_vgid_is_cached(const char *vgid);
 uint64_t lvmcache_smallest_mda_size(struct lvmcache_info *info);
 
+void lvmcache_replace_dev(struct cmd_context *cmd, struct physical_volume *pv,
+			struct device *dev);
+
 #endif
diff --git a/tools/toollib.c b/tools/toollib.c
index e739ecf9e..9d2b88b8c 100644
--- a/tools/toollib.c
+++ b/tools/toollib.c
@@ -2221,6 +2221,7 @@ static int _process_pvs_in_vg(struct cmd_context *cmd,
 	struct physical_volume *pv;
 	struct pv_list *pvl;
 	struct device_id_list *dil;
+	struct device *dev_orig;
 	const char *pv_name;
 	int process_pv;
 	int dev_found;
@@ -2298,17 +2299,21 @@ static int _process_pvs_in_vg(struct cmd_context *cmd,
 					_device_list_remove(arg_devices, dil->dev);
 
 					/*
-					 * This will simply display the same PV
-					 * multiple times.  Further changes would
-					 * be needed to make this display the details
-					 * of dil->dev instead of pv->dev.
+					 * Replace pv->dev with this dil->dev
+					 * in lvmcache so the duplicate dev
+					 * info will be reported.
 					 */
+					dev_orig = pv->dev;
+					lvmcache_replace_dev(cmd, pv, dil->dev);
 
 					ret = process_single_pv(cmd, vg, pv, handle);
 					if (ret != ECMD_PROCESSED)
 						stack;
 					if (ret > ret_max)
 						ret_max = ret;
+
+					/* Put the cache state back as it was. */
+					lvmcache_replace_dev(cmd, pv, dev_orig);
 				}
 			}
 		}