activation: flag temporary LVs internally

Add LV_TEMPORARY flag for LVs with limited existence during command
execution. Such LVs are temporary in way that they need to be activated,
some action done and then removed immediately. Such LVs are just like
any normal LV - the only difference is that they are removed during
LVM command execution. This is also the case for LVs representing
future pool metadata spare LVs which we need to initialize by using
the usual LV before they are declared as pool metadata spare.

We can optimize some other parts like udev to do a better job if
it knows that the LV is temporary and any processing on it is just
useless.

This flag is orthogonal to LV_NOSCAN flag introduced recently
as LV_NOSCAN flag is primarily used to mark an LV for the scanning
to be avoided before the zeroing of the device happens. The LV_TEMPORARY
flag makes a difference between a full-fledged LV visible in the system
and the LV just used as a temporary overlay for some action that needs to
be done on underlying PVs.

For example: lvcreate --thinpool POOL --zero n -L 1G vg

- first, the usual LV is created to do a clean up for pool metadata
  spare. The LV is activated, zeroed, deactivated.

- between "activated" and "zeroed" stage, the LV_NOSCAN flag is used
  to avoid any scanning in udev

- betwen "zeroed" and "deactivated" stage, we need to avoid the WATCH
  udev rule, but since the LV is just a usual LV, we can't make a
  difference. The LV_TEMPORARY internal LV flag helps here. If we
  create the LV with this flag, the DM_UDEV_DISABLE_DISK_RULES
  and DM_UDEV_DISABLE_OTHER_RULES flag are set (just like as it is
  with "invisible" and non-top-level LVs) - udev is directed to
  skip WATCH rule use.

- if the LV_TEMPORARY flag was not used, there would normally be
  a WATCH event generated once the LV is closed after "zeroed"
  stage. This will make problems with immediated deactivation that
  follows.

diff --git a/WHATS_NEW b/WHATS_NEW
index 7cfa87c50161ba9b926447073c9f4b8d493af5f9..49f37a4489b341ecad3e8d731399f12c1a9d7c03 100644 (file)
--- a/WHATS_NEW
+++ b/WHATS_NEW
@@ -1,5 +1,6 @@
 Version 2.02.104
 ===================================
+  Add internal flag for temporary LVs to properly direct udev to not interfere.
   Fix endless loop in blkdeactivate <device>... if unable to umount/deactivate.
   Add dev-block-<major>:<minor>.device systemd alias for complete PV tracking.
   Use major:minor as short form of --major and --minor arg for pvscan --cache.

diff --git a/daemons/clvmd/lvm-functions.c b/daemons/clvmd/lvm-functions.c
index f544218f37849ca567cc176b8727575f2037ff77..b15732fb0f01a00fdf6be774962a5bfea5ffbb6c 100644 (file)
--- a/daemons/clvmd/lvm-functions.c
+++ b/daemons/clvmd/lvm-functions.c
@@ -401,7 +401,7 @@ static int do_activate_lv(char *resource, unsigned char command, unsigned char l
        }
 
        /* Now activate it */
-       if (!lv_activate(cmd, resource, exclusive, 0, NULL))
+       if (!lv_activate(cmd, resource, exclusive, 0, 0, NULL))
                goto error;
 
        return 0;

diff --git a/lib/activate/activate.c b/lib/activate/activate.c
index 131a09325edda50c0b5a6094c366cbc71649036f..006681e12fe6bf19b5232dada4cf6659794cd819 100644 (file)
--- a/lib/activate/activate.c
+++ b/lib/activate/activate.c
@@ -338,12 +338,12 @@ int lv_activation_filter(struct cmd_context *cmd, const char *lvid_s,
        return 1;
 }
 int lv_activate(struct cmd_context *cmd, const char *lvid_s, int exclusive, int noscan,
-               struct logical_volume *lv)
+               int temporary, struct logical_volume *lv)
 {
        return 1;
 }
 int lv_activate_with_filter(struct cmd_context *cmd, const char *lvid_s, int exclusive,
-                           int noscan, struct logical_volume *lv)
+                           int noscan, int temporary, struct logical_volume *lv)
 {
        return 1;
 }
@@ -2055,10 +2055,11 @@ static int _lv_activate(struct cmd_context *cmd, const char *lvid_s,
        if (filter)
                laopts->read_only = _passes_readonly_filter(cmd, lv);
 
-       log_debug_activation("Activating %s/%s%s%s%s.", lv->vg->name, lv->name,
+       log_debug_activation("Activating %s/%s%s%s%s%s.", lv->vg->name, lv->name,
                             laopts->exclusive ? " exclusively" : "",
                             laopts->read_only ? " read-only" : "",
-                            laopts->noscan ? " noscan" : "");
+                            laopts->noscan ? " noscan" : "",
+                            laopts->temporary ? " temporary" : "");
 
        if (!lv_info(cmd, lv, 0, &info, 0, 0))
                goto_out;
@@ -2096,9 +2097,11 @@ out:
 
 /* Activate LV */
 int lv_activate(struct cmd_context *cmd, const char *lvid_s, int exclusive,
-               int noscan, struct logical_volume *lv)
+               int noscan, int temporary, struct logical_volume *lv)
 {
-       struct lv_activate_opts laopts = { .exclusive = exclusive, .noscan = noscan };
+       struct lv_activate_opts laopts = { .exclusive = exclusive,
+                                          .noscan = noscan,
+                                          .temporary = temporary };
 
        if (!_lv_activate(cmd, lvid_s, &laopts, 0, lv))
                return_0;
@@ -2108,9 +2111,11 @@ int lv_activate(struct cmd_context *cmd, const char *lvid_s, int exclusive,
 
 /* Activate LV only if it passes filter */
 int lv_activate_with_filter(struct cmd_context *cmd, const char *lvid_s, int exclusive,
-                           int noscan, struct logical_volume *lv)
+                           int noscan, int temporary, struct logical_volume *lv)
 {
-       struct lv_activate_opts laopts = { .exclusive = exclusive, .noscan = noscan  };
+       struct lv_activate_opts laopts = { .exclusive = exclusive,
+                                          .noscan = noscan,
+                                          .temporary = temporary };
 
        if (!_lv_activate(cmd, lvid_s, &laopts, 1, lv))
                return_0;

diff --git a/lib/activate/activate.h b/lib/activate/activate.h
index 4eac320bc810963c961569c9cd53fec50053a76f..df888cdf7687f4127989a1b15b0653752fb35a11 100644 (file)
--- a/lib/activate/activate.h
+++ b/lib/activate/activate.h
@@ -38,7 +38,18 @@ struct lv_activate_opts {
        int skip_in_use;
        unsigned revert;
        unsigned read_only;
-       unsigned noscan;
+       unsigned noscan;        /* Mark this LV to avoid its scanning. This also
+                                  directs udev to use proper udev flag to avoid
+                                  any scanning in udev. This udev flag is automatically
+                                  dropped in udev db on any spurious event that follows. */
+       unsigned temporary;     /* Mark this LV as temporary. It means, the LV
+                                * is created, used and deactivated within single
+                                * LVM command execution. Such LVs are mostly helper
+                                * LVs to do some action or cleanup before the proper
+                                * LV is created. This also directs udev to use proper
+                                * set of flags to avoid any scanning in udev. These udev
+                                * flags are persistent in udev db for any spurious event
+                                * that follows. */
 };
 
 /* target attribute flags */
@@ -81,9 +92,10 @@ int lv_suspend_if_active(struct cmd_context *cmd, const char *lvid_s, unsigned o
 int lv_resume(struct cmd_context *cmd, const char *lvid_s, unsigned origin_only, struct logical_volume *lv);
 int lv_resume_if_active(struct cmd_context *cmd, const char *lvid_s,
                        unsigned origin_only, unsigned exclusive, unsigned revert, struct logical_volume *lv);
-int lv_activate(struct cmd_context *cmd, const char *lvid_s, int exclusive, int noscan, struct logical_volume *lv);
-int lv_activate_with_filter(struct cmd_context *cmd, const char *lvid_s,
-                           int exclusive, int noscan, struct logical_volume *lv);
+int lv_activate(struct cmd_context *cmd, const char *lvid_s, int exclusive,
+               int noscan, int temporary, struct logical_volume *lv);
+int lv_activate_with_filter(struct cmd_context *cmd, const char *lvid_s, int exclusive,
+                           int noscan, int temporary, struct logical_volume *lv);
 int lv_deactivate(struct cmd_context *cmd, const char *lvid_s, struct logical_volume *lv);
 
 int lv_mknodes(struct cmd_context *cmd, const struct logical_volume *lv);

diff --git a/lib/activate/dev_manager.c b/lib/activate/dev_manager.c
index 0f5a04cce31e83d786e853f5c2f83adb6fbb1f3f..0b911f24491006451edcf3d199a3d7eeefdc7f87 100644 (file)
--- a/lib/activate/dev_manager.c
+++ b/lib/activate/dev_manager.c
@@ -1400,7 +1400,7 @@ static int _check_udev_fallback(struct cmd_context *cmd)
 #endif /* UDEV_SYNC_SUPPORT */
 
 static uint16_t _get_udev_flags(struct dev_manager *dm, struct logical_volume *lv,
-                               const char *layer, uint16_t flags)
+                               const char *layer, int noscan, int temporary)
 {
        uint16_t udev_flags = 0;
 
@@ -1449,9 +1449,14 @@ static uint16_t _get_udev_flags(struct dev_manager *dm, struct logical_volume *l
                              DM_UDEV_DISABLE_SUBSYSTEM_RULES_FLAG;
 
        /*
-        * Firmly set requested flags.
+        * LVM subsystem specific flags.
         */
-       udev_flags |= flags;
+       if (noscan)
+               udev_flags |= DM_SUBSYSTEM_UDEV_FLAG0;
+
+       if (temporary)
+               udev_flags |= DM_UDEV_DISABLE_DISK_RULES_FLAG |
+                             DM_UDEV_DISABLE_OTHER_RULES_FLAG;
 
        return udev_flags;
 }
@@ -1499,7 +1504,7 @@ static int _add_dev_to_dtree(struct dev_manager *dm, struct dm_tree *dtree,
        }
 
        if (info.exists && !dm_tree_add_dev_with_udev_flags(dtree, info.major, info.minor,
-                                                       _get_udev_flags(dm, lv, layer, 0))) {
+                                                       _get_udev_flags(dm, lv, layer, 0, 0))) {
                log_error("Failed to add device (%" PRIu32 ":%" PRIu32") to dtree",
                          info.major, info.minor);
                return 0;
@@ -2340,7 +2345,7 @@ static int _set_udev_flags_for_children(struct dev_manager *dm,
                }
 
                dm_tree_node_set_udev_flags(child,
-                                           _get_udev_flags(dm, lvl->lv, NULL, 0));
+                                           _get_udev_flags(dm, lvl->lv, NULL, 0, 0));
        }
 
        return 1;
@@ -2417,8 +2422,7 @@ static int _add_new_lv_to_dtree(struct dev_manager *dm, struct dm_tree *dtree,
                                             read_only_lv(lv, laopts),
                                             ((lv->vg->status & PRECOMMITTED) | laopts->revert) ? 1 : 0,
                                             lvlayer,
-                                            _get_udev_flags(dm, lv, layer,
-                                               laopts->noscan ? LVM_UDEV_NOSCAN_FLAG : 0))))
+                                            _get_udev_flags(dm, lv, layer, laopts->noscan, laopts->temporary))))
                return_0;
 
        /* Store existing name so we can do rename later */

diff --git a/lib/format_text/flags.c b/lib/format_text/flags.c
index a27b791d9b7e85a9e99b8caf13c2ff7143e85726..e31429e25d168e002dd3c7fcbef27c362a5cc86b 100644 (file)
--- a/lib/format_text/flags.c
+++ b/lib/format_text/flags.c
@@ -62,6 +62,7 @@ static const struct flag _lv_flags[] = {
        {LV_WRITEMOSTLY, "WRITEMOSTLY", STATUS_FLAG},
        {LV_ACTIVATION_SKIP, "ACTIVATION_SKIP", COMPATIBLE_FLAG},
        {LV_NOSCAN, NULL, 0},
+       {LV_TEMPORARY, NULL, 0},
        {POOL_METADATA_SPARE, NULL, 0},
        {RAID, NULL, 0},
        {RAID_META, NULL, 0},

diff --git a/lib/locking/file_locking.c b/lib/locking/file_locking.c
index b6b2b109c48014dd6130dec31924f067fcd587c8..ab3dabd38867a17727f56bcd4df256ae0669fc65 100644 (file)
--- a/lib/locking/file_locking.c
+++ b/lib/locking/file_locking.c
@@ -305,7 +305,8 @@ static int _file_lock_resource(struct cmd_context *cmd, const char *resource,
                        break;
                case LCK_READ:
                        log_very_verbose("Locking LV %s (R)", resource);
-                       if (!lv_activate_with_filter(cmd, resource, 0, lv->status & LV_NOSCAN ? 1 : 0, lv_ondisk(lv)))
+                       if (!lv_activate_with_filter(cmd, resource, 0, lv->status & LV_NOSCAN ? 1 : 0,
+                                                    lv->status & LV_TEMPORARY ? 1 : 0, lv_ondisk(lv)))
                                return 0;
                        break;
                case LCK_PREAD:
@@ -318,7 +319,8 @@ static int _file_lock_resource(struct cmd_context *cmd, const char *resource,
                        break;
                case LCK_EXCL:
                        log_very_verbose("Locking LV %s (EX)", resource);
-                       if (!lv_activate_with_filter(cmd, resource, 1, lv->status & LV_NOSCAN ? 1 : 0, lv_ondisk(lv)))
+                       if (!lv_activate_with_filter(cmd, resource, 1, lv->status & LV_NOSCAN ? 1 : 0,
+                                                    lv->status & LV_TEMPORARY ? 1 : 0, lv_ondisk(lv)))
                                return 0;
                        break;
                default:

diff --git a/lib/locking/no_locking.c b/lib/locking/no_locking.c
index 4772706648621107166d5fb0d14de90dcab970f3..dac2f808559004cfbbaa1ff8769ec0e81cc06661 100644 (file)
--- a/lib/locking/no_locking.c
+++ b/lib/locking/no_locking.c
@@ -48,11 +48,13 @@ static int _no_lock_resource(struct cmd_context *cmd, const char *resource,
                case LCK_UNLOCK:
                        return lv_resume_if_active(cmd, resource, (flags & LCK_ORIGIN_ONLY) ? 1: 0, 0, (flags & LCK_REVERT) ? 1 : 0, lv_ondisk(lv));
                case LCK_READ:
-                       return lv_activate_with_filter(cmd, resource, 0, lv->status & LV_NOSCAN ? 1 : 0, lv_ondisk(lv));
+                       return lv_activate_with_filter(cmd, resource, 0, lv->status & LV_NOSCAN ? 1 : 0,
+                                                      lv->status & LV_TEMPORARY ? 1 : 0, lv_ondisk(lv));
                case LCK_WRITE:
                        return lv_suspend_if_active(cmd, resource, (flags & LCK_ORIGIN_ONLY) ? 1 : 0, 0, lv_ondisk(lv), lv);
                case LCK_EXCL:
-                       return lv_activate_with_filter(cmd, resource, 1, lv->status & LV_NOSCAN ? 1 : 0, lv_ondisk(lv));
+                       return lv_activate_with_filter(cmd, resource, 1, lv->status & LV_NOSCAN ? 1 : 0,
+                                                      lv->status & LV_TEMPORARY ? 1 : 0, lv_ondisk(lv));
                default:
                        break;
                }

diff --git a/lib/metadata/lv_manip.c b/lib/metadata/lv_manip.c
index 383bab1a9c56b8285b2db93964a1c152f721e9df..88fceb2b7a898bf29c7cfce3e2267010d2599f4d 100644 (file)
--- a/lib/metadata/lv_manip.c
+++ b/lib/metadata/lv_manip.c
@@ -5987,6 +5987,9 @@ static struct logical_volume *_lv_create_an_lv(struct volume_group *vg,
        if (lp->zero)
                lv->status |= LV_NOSCAN;
 
+       if (lp->temporary)
+               lv->status |= LV_TEMPORARY;
+
        if (lv_is_thin_pool(lv)) {
                if (is_change_activating(lp->activate)) {
                        if (vg_is_clustered(lv->vg)) {

diff --git a/lib/metadata/metadata-exported.h b/lib/metadata/metadata-exported.h
index 1e9543ac89bad4a4868316d04602ae2a6889de47..c00e4e580da029c9d2dd9790470b05cc1405e879 100644 (file)
--- a/lib/metadata/metadata-exported.h
+++ b/lib/metadata/metadata-exported.h
@@ -102,7 +102,12 @@
 #define LV_WRITEMOSTLY         UINT64_C(0x0000020000000000)    /* LV (RAID1) */
 
 #define LV_ACTIVATION_SKIP     UINT64_C(0x0000040000000000)    /* LV */
-#define LV_NOSCAN              UINT64_C(0x0000080000000000)    /* LV */
+#define LV_NOSCAN              UINT64_C(0x0000080000000000)    /* LV - internal use only - the LV
+                                                                       should not be scanned */
+#define LV_TEMPORARY           UINT64_C(0x0000100000000000)    /* LV - internal use only - the LV
+                                                                       is supposed to be created and
+                                                                       removed during single LVM
+                                                                       command execution. */
 
 /* Format features flags */
 #define FMT_SEGMENTS           0x00000001U     /* Arbitrary segment params? */
@@ -721,6 +726,7 @@ struct lvcreate_params {
        int log_count; /* mirror */
        int nosync; /* mirror */
        int poolmetadataspare; /* thin pool */
+       int temporary; /* temporary LV */
 #define ACTIVATION_SKIP_SET            0x01 /* request to set LV activation skip flag state */
 #define ACTIVATION_SKIP_SET_ENABLED    0x02 /* set the LV activation skip flag state to 'enabled' */
 #define ACTIVATION_SKIP_IGNORE         0x04 /* request to ignore LV activation skip flag (if any) */

diff --git a/lib/metadata/thin_manip.c b/lib/metadata/thin_manip.c
index a6e0fc24614d5f7abd70584f72ed032400e73e05..bd5b117f3194de4bf8d01733188847c9c5eba20b 100644 (file)
--- a/lib/metadata/thin_manip.c
+++ b/lib/metadata/thin_manip.c
@@ -809,6 +809,7 @@ static struct logical_volume *_alloc_pool_metadata_spare(struct volume_group *vg
                .stripes = 1,
                .vg_name = vg->name,
                .zero = 1,
+               .temporary = 1,
        };
 
        dm_list_init(&lp.tags);