Add -p switch to "zpool get"
[zfs.git] / module / zfs / vdev_label.c
index 8b40087..1fe36fe 100644 (file)
  *
  * CDDL HEADER END
  */
+
 /*
  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2012 by Delphix. All rights reserved.
  */
 
 /*
  *     txg             Transaction group in which this label was written
  *     pool_guid       Unique identifier for this pool
  *     vdev_tree       An nvlist describing vdev tree.
+ *     features_for_read
+ *                     An nvlist of the features necessary for reading the MOS.
  *
  * Each leaf device label also contains the following:
  *
@@ -212,7 +216,7 @@ vdev_config_generate(spa_t *spa, vdev_t *vd, boolean_t getstats,
 {
        nvlist_t *nv = NULL;
 
-       VERIFY(nvlist_alloc(&nv, NV_UNIQUE_NAME, KM_SLEEP) == 0);
+       VERIFY(nvlist_alloc(&nv, NV_UNIQUE_NAME, KM_PUSHPAGE) == 0);
 
        VERIFY(nvlist_add_string(nv, ZPOOL_CONFIG_TYPE,
            vd->vdev_ops->vdev_op_type) == 0);
@@ -319,7 +323,7 @@ vdev_config_generate(spa_t *spa, vdev_t *vd, boolean_t getstats,
                ASSERT(!vd->vdev_ishole);
 
                child = kmem_alloc(vd->vdev_children * sizeof (nvlist_t *),
-                   KM_SLEEP);
+                   KM_PUSHPAGE);
 
                for (c = 0, idx = 0; c < vd->vdev_children; c++) {
                        vdev_t *cvd = vd->vdev_child[c];
@@ -408,7 +412,7 @@ vdev_top_config_generate(spa_t *spa, nvlist_t *config)
        uint64_t *array;
        uint_t c, idx;
 
-       array = kmem_alloc(rvd->vdev_children * sizeof (uint64_t), KM_SLEEP);
+       array = kmem_alloc(rvd->vdev_children * sizeof (uint64_t), KM_PUSHPAGE);
 
        for (c = 0, idx = 0; c < rvd->vdev_children; c++) {
                vdev_t *tvd = rvd->vdev_child[c];
@@ -428,13 +432,23 @@ vdev_top_config_generate(spa_t *spa, nvlist_t *config)
        kmem_free(array, rvd->vdev_children * sizeof (uint64_t));
 }
 
+/*
+ * Returns the configuration from the label of the given vdev. For vdevs
+ * which don't have a txg value stored on their label (i.e. spares/cache)
+ * or have not been completely initialized (txg = 0) just return
+ * the configuration from the first valid label we find. Otherwise,
+ * find the most up-to-date label that does not exceed the specified
+ * 'txg' value.
+ */
 nvlist_t *
-vdev_label_read_config(vdev_t *vd)
+vdev_label_read_config(vdev_t *vd, uint64_t txg)
 {
        spa_t *spa = vd->vdev_spa;
        nvlist_t *config = NULL;
        vdev_phys_t *vp;
        zio_t *zio;
+       uint64_t best_txg = 0;
+       int error = 0;
        int flags = ZIO_FLAG_CONFIG_WRITER | ZIO_FLAG_CANFAIL |
            ZIO_FLAG_SPECULATIVE;
        int l;
@@ -448,6 +462,7 @@ vdev_label_read_config(vdev_t *vd)
 
 retry:
        for (l = 0; l < VDEV_LABELS; l++) {
+               nvlist_t *label = NULL;
 
                zio = zio_root(spa, NULL, NULL, flags);
 
@@ -457,12 +472,31 @@ retry:
 
                if (zio_wait(zio) == 0 &&
                    nvlist_unpack(vp->vp_nvlist, sizeof (vp->vp_nvlist),
-                   &config, 0) == 0)
-                       break;
+                   &label, 0) == 0) {
+                       uint64_t label_txg = 0;
+
+                       /*
+                        * Auxiliary vdevs won't have txg values in their
+                        * labels and newly added vdevs may not have been
+                        * completely initialized so just return the
+                        * configuration from the first valid label we
+                        * encounter.
+                        */
+                       error = nvlist_lookup_uint64(label,
+                           ZPOOL_CONFIG_POOL_TXG, &label_txg);
+                       if ((error || label_txg == 0) && !config) {
+                               config = label;
+                               break;
+                       } else if (label_txg <= txg && label_txg > best_txg) {
+                               best_txg = label_txg;
+                               nvlist_free(config);
+                               config = fnvlist_dup(label);
+                       }
+               }
 
-               if (config != NULL) {
-                       nvlist_free(config);
-                       config = NULL;
+               if (label != NULL) {
+                       nvlist_free(label);
+                       label = NULL;
                }
        }
 
@@ -497,7 +531,7 @@ vdev_inuse(vdev_t *vd, uint64_t crtxg, vdev_labeltype_t reason,
        /*
         * Read the label, if any, and perform some basic sanity checks.
         */
-       if ((label = vdev_label_read_config(vd)) == NULL)
+       if ((label = vdev_label_read_config(vd, -1ULL)) == NULL)
                return (B_FALSE);
 
        (void) nvlist_lookup_uint64(label, ZPOOL_CONFIG_CREATE_TXG,
@@ -612,7 +646,7 @@ vdev_label_init(vdev_t *vd, uint64_t crtxg, vdev_labeltype_t reason)
        char *buf;
        size_t buflen;
        int error;
-       uint64_t spare_guid, l2cache_guid;
+       uint64_t spare_guid = 0, l2cache_guid = 0;
        int flags = ZIO_FLAG_CONFIG_WRITER | ZIO_FLAG_CANFAIL;
        int c, l;
        vdev_t *pvd;
@@ -709,7 +743,7 @@ vdev_label_init(vdev_t *vd, uint64_t crtxg, vdev_labeltype_t reason)
                 * active hot spare (in which case we want to revert the
                 * labels).
                 */
-               VERIFY(nvlist_alloc(&label, NV_UNIQUE_NAME, KM_SLEEP) == 0);
+               VERIFY(nvlist_alloc(&label, NV_UNIQUE_NAME, KM_PUSHPAGE) == 0);
 
                VERIFY(nvlist_add_uint64(label, ZPOOL_CONFIG_VERSION,
                    spa_version(spa)) == 0);
@@ -722,7 +756,7 @@ vdev_label_init(vdev_t *vd, uint64_t crtxg, vdev_labeltype_t reason)
                /*
                 * For level 2 ARC devices, add a special label.
                 */
-               VERIFY(nvlist_alloc(&label, NV_UNIQUE_NAME, KM_SLEEP) == 0);
+               VERIFY(nvlist_alloc(&label, NV_UNIQUE_NAME, KM_PUSHPAGE) == 0);
 
                VERIFY(nvlist_add_uint64(label, ZPOOL_CONFIG_VERSION,
                    spa_version(spa)) == 0);
@@ -749,7 +783,7 @@ vdev_label_init(vdev_t *vd, uint64_t crtxg, vdev_labeltype_t reason)
        buf = vp->vp_nvlist;
        buflen = sizeof (vp->vp_nvlist);
 
-       error = nvlist_pack(label, &buf, &buflen, NV_ENCODE_XDR, KM_SLEEP);
+       error = nvlist_pack(label, &buf, &buflen, NV_ENCODE_XDR, KM_PUSHPAGE);
        if (error != 0) {
                nvlist_free(label);
                zio_buf_free(vp, sizeof (vdev_phys_t));
@@ -838,7 +872,7 @@ retry:
  * come back up, we fail to see the uberblock for txg + 1 because, say,
  * it was on a mirrored device and the replica to which we wrote txg + 1
  * is now offline.  If we then make some changes and sync txg + 1, and then
- * the missing replica comes back, then for a new seconds we'll have two
+ * the missing replica comes back, then for a few seconds we'll have two
  * conflicting uberblocks on disk with the same txg.  The solution is simple:
  * among uberblocks with equal txg, choose the one with the latest timestamp.
  */
@@ -858,47 +892,49 @@ vdev_uberblock_compare(uberblock_t *ub1, uberblock_t *ub2)
        return (0);
 }
 
+struct ubl_cbdata {
+       uberblock_t     *ubl_ubbest;    /* Best uberblock */
+       vdev_t          *ubl_vd;        /* vdev associated with the above */
+};
+
 static void
 vdev_uberblock_load_done(zio_t *zio)
 {
+       vdev_t *vd = zio->io_vd;
        spa_t *spa = zio->io_spa;
        zio_t *rio = zio->io_private;
        uberblock_t *ub = zio->io_data;
-       uberblock_t *ubbest = rio->io_private;
+       struct ubl_cbdata *cbp = rio->io_private;
 
-       ASSERT3U(zio->io_size, ==, VDEV_UBERBLOCK_SIZE(zio->io_vd));
+       ASSERT3U(zio->io_size, ==, VDEV_UBERBLOCK_SIZE(vd));
 
        if (zio->io_error == 0 && uberblock_verify(ub) == 0) {
                mutex_enter(&rio->io_lock);
                if (ub->ub_txg <= spa->spa_load_max_txg &&
-                   vdev_uberblock_compare(ub, ubbest) > 0)
-                       *ubbest = *ub;
+                   vdev_uberblock_compare(ub, cbp->ubl_ubbest) > 0) {
+                       /*
+                        * Keep track of the vdev in which this uberblock
+                        * was found. We will use this information later
+                        * to obtain the config nvlist associated with
+                        * this uberblock.
+                        */
+                       *cbp->ubl_ubbest = *ub;
+                       cbp->ubl_vd = vd;
+               }
                mutex_exit(&rio->io_lock);
        }
 
        zio_buf_free(zio->io_data, zio->io_size);
 }
 
-void
-vdev_uberblock_load(zio_t *zio, vdev_t *vd, uberblock_t *ubbest)
+static void
+vdev_uberblock_load_impl(zio_t *zio, vdev_t *vd, int flags,
+    struct ubl_cbdata *cbp)
 {
-       spa_t *spa = vd->vdev_spa;
-       vdev_t *rvd = spa->spa_root_vdev;
-       int flags = ZIO_FLAG_CONFIG_WRITER | ZIO_FLAG_CANFAIL |
-           ZIO_FLAG_SPECULATIVE | ZIO_FLAG_TRYHARD;
        int c, l, n;
 
-       if (vd == rvd) {
-               ASSERT(zio == NULL);
-               spa_config_enter(spa, SCL_ALL, FTAG, RW_WRITER);
-               zio = zio_root(spa, NULL, ubbest, flags);
-               bzero(ubbest, sizeof (uberblock_t));
-       }
-
-       ASSERT(zio != NULL);
-
        for (c = 0; c < vd->vdev_children; c++)
-               vdev_uberblock_load(zio, vd->vdev_child[c], ubbest);
+               vdev_uberblock_load_impl(zio, vd->vdev_child[c], flags, cbp);
 
        if (vd->vdev_ops->vdev_op_leaf && vdev_readable(vd)) {
                for (l = 0; l < VDEV_LABELS; l++) {
@@ -911,11 +947,46 @@ vdev_uberblock_load(zio_t *zio, vdev_t *vd, uberblock_t *ubbest)
                        }
                }
        }
+}
 
-       if (vd == rvd) {
-               (void) zio_wait(zio);
-               spa_config_exit(spa, SCL_ALL, FTAG);
-       }
+/*
+ * Reads the 'best' uberblock from disk along with its associated
+ * configuration. First, we read the uberblock array of each label of each
+ * vdev, keeping track of the uberblock with the highest txg in each array.
+ * Then, we read the configuration from the same vdev as the best uberblock.
+ */
+void
+vdev_uberblock_load(vdev_t *rvd, uberblock_t *ub, nvlist_t **config)
+{
+       zio_t *zio;
+       spa_t *spa = rvd->vdev_spa;
+       struct ubl_cbdata cb;
+       int flags = ZIO_FLAG_CONFIG_WRITER | ZIO_FLAG_CANFAIL |
+           ZIO_FLAG_SPECULATIVE | ZIO_FLAG_TRYHARD;
+
+       ASSERT(ub);
+       ASSERT(config);
+
+       bzero(ub, sizeof (uberblock_t));
+       *config = NULL;
+
+       cb.ubl_ubbest = ub;
+       cb.ubl_vd = NULL;
+
+       spa_config_enter(spa, SCL_ALL, FTAG, RW_WRITER);
+       zio = zio_root(spa, NULL, &cb, flags);
+       vdev_uberblock_load_impl(zio, rvd, flags, &cb);
+       (void) zio_wait(zio);
+
+       /*
+        * It's possible that the best uberblock was discovered on a label
+        * that has a configuration which was written in a future txg.
+        * Search all labels on this vdev to find the configuration that
+        * matches the txg for our uberblock.
+        */
+       if (cb.ubl_vd != NULL)
+               *config = vdev_label_read_config(cb.ubl_vd, ub->ub_txg);
+       spa_config_exit(spa, SCL_ALL, FTAG);
 }
 
 /*
@@ -1061,7 +1132,7 @@ vdev_label_sync(zio_t *zio, vdev_t *vd, int l, uint64_t txg, int flags)
        buf = vp->vp_nvlist;
        buflen = sizeof (vp->vp_nvlist);
 
-       if (nvlist_pack(label, &buf, &buflen, NV_ENCODE_XDR, KM_SLEEP) == 0) {
+       if (nvlist_pack(label, &buf, &buflen, NV_ENCODE_XDR, KM_PUSHPAGE) == 0) {
                for (; l < VDEV_LABELS; l += 2) {
                        vdev_label_write(zio, vd, l, vp,
                            offsetof(vdev_label_t, vl_vdev_phys),
@@ -1094,7 +1165,7 @@ vdev_label_sync_list(spa_t *spa, int l, uint64_t txg, int flags)
 
                ASSERT(!vd->vdev_ishole);
 
-               good_writes = kmem_zalloc(sizeof (uint64_t), KM_SLEEP);
+               good_writes = kmem_zalloc(sizeof (uint64_t), KM_PUSHPAGE);
                vio = zio_null(zio, spa, NULL,
                    (vd->vdev_islog || vd->vdev_aux != NULL) ?
                    vdev_label_sync_ignore_done : vdev_label_sync_top_done,