--- /dev/null
+/*
+ * CDDL HEADER START
+ *
+ * The contents of this file are subject to the terms of the
+ * Common Development and Distribution License (the "License").
+ * You may not use this file except in compliance with the License.
+ *
+ * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+ * or http://www.opensolaris.org/os/licensing.
+ * See the License for the specific language governing permissions
+ * and limitations under the License.
+ *
+ * When distributing Covered Code, include this CDDL HEADER in each
+ * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+ * If applicable, add the following below this CDDL HEADER, with the
+ * fields enclosed by brackets "[]" replaced with your own identifying
+ * information: Portions Copyright [yyyy] [name of copyright owner]
+ *
+ * CDDL HEADER END
+ */
+/*
+ * Copyright 2008 Sun Microsystems, Inc. All rights reserved.
+ * Use is subject to license terms.
+ */
+
+/*
+ * ZFS fault injection
+ *
+ * To handle fault injection, we keep track of a series of zinject_record_t
+ * structures which describe which logical block(s) should be injected with a
+ * fault. These are kept in a global list. Each record corresponds to a given
+ * spa_t and maintains a special hold on the spa_t so that it cannot be deleted
+ * or exported while the injection record exists.
+ *
+ * Device level injection is done using the 'zi_guid' field. If this is set, it
+ * means that the error is destined for a particular device, not a piece of
+ * data.
+ *
+ * This is a rather poor data structure and algorithm, but we don't expect more
+ * than a few faults at any one time, so it should be sufficient for our needs.
+ */
+
+#include <sys/arc.h>
+#include <sys/zio_impl.h>
+#include <sys/zfs_ioctl.h>
+#include <sys/spa_impl.h>
+#include <sys/vdev_impl.h>
+#include <sys/fs/zfs.h>
+
+uint32_t zio_injection_enabled;
+
+typedef struct inject_handler {
+ int zi_id;
+ spa_t *zi_spa;
+ zinject_record_t zi_record;
+ list_node_t zi_link;
+} inject_handler_t;
+
+static list_t inject_handlers;
+static krwlock_t inject_lock;
+static int inject_next_id = 1;
+
+/*
+ * Returns true if the given record matches the I/O in progress.
+ */
+static boolean_t
+zio_match_handler(zbookmark_t *zb, uint64_t type,
+ zinject_record_t *record, int error)
+{
+ /*
+ * Check for a match against the MOS, which is based on type
+ */
+ if (zb->zb_objset == 0 && record->zi_objset == 0 &&
+ record->zi_object == 0) {
+ if (record->zi_type == DMU_OT_NONE ||
+ type == record->zi_type)
+ return (record->zi_freq == 0 ||
+ spa_get_random(100) < record->zi_freq);
+ else
+ return (B_FALSE);
+ }
+
+ /*
+ * Check for an exact match.
+ */
+ if (zb->zb_objset == record->zi_objset &&
+ zb->zb_object == record->zi_object &&
+ zb->zb_level == record->zi_level &&
+ zb->zb_blkid >= record->zi_start &&
+ zb->zb_blkid <= record->zi_end &&
+ error == record->zi_error)
+ return (record->zi_freq == 0 ||
+ spa_get_random(100) < record->zi_freq);
+
+ return (B_FALSE);
+}
+
+/*
+ * Determine if the I/O in question should return failure. Returns the errno
+ * to be returned to the caller.
+ */
+int
+zio_handle_fault_injection(zio_t *zio, int error)
+{
+ int ret = 0;
+ inject_handler_t *handler;
+
+ /*
+ * Ignore I/O not associated with any logical data.
+ */
+ if (zio->io_logical == NULL)
+ return (0);
+
+ /*
+ * Currently, we only support fault injection on reads.
+ */
+ if (zio->io_type != ZIO_TYPE_READ)
+ return (0);
+
+ rw_enter(&inject_lock, RW_READER);
+
+ for (handler = list_head(&inject_handlers); handler != NULL;
+ handler = list_next(&inject_handlers, handler)) {
+
+ /* Ignore errors not destined for this pool */
+ if (zio->io_spa != handler->zi_spa)
+ continue;
+
+ /* Ignore device errors */
+ if (handler->zi_record.zi_guid != 0)
+ continue;
+
+ /* If this handler matches, return EIO */
+ if (zio_match_handler(&zio->io_logical->io_bookmark,
+ zio->io_bp ? BP_GET_TYPE(zio->io_bp) : DMU_OT_NONE,
+ &handler->zi_record, error)) {
+ ret = error;
+ break;
+ }
+ }
+
+ rw_exit(&inject_lock);
+
+ return (ret);
+}
+
+/*
+ * Determine if the zio is part of a label update and has an injection
+ * handler associated with that portion of the label. Currently, we
+ * allow error injection in either the nvlist or the uberblock region of
+ * of the vdev label.
+ */
+int
+zio_handle_label_injection(zio_t *zio, int error)
+{
+ inject_handler_t *handler;
+ vdev_t *vd = zio->io_vd;
+ uint64_t offset = zio->io_offset;
+ int label;
+ int ret = 0;
+
+ if (offset + zio->io_size > VDEV_LABEL_START_SIZE &&
+ offset < vd->vdev_psize - VDEV_LABEL_END_SIZE)
+ return (0);
+
+ rw_enter(&inject_lock, RW_READER);
+
+ for (handler = list_head(&inject_handlers); handler != NULL;
+ handler = list_next(&inject_handlers, handler)) {
+ uint64_t start = handler->zi_record.zi_start;
+ uint64_t end = handler->zi_record.zi_end;
+
+ /* Ignore device only faults */
+ if (handler->zi_record.zi_start == 0)
+ continue;
+
+ /*
+ * The injection region is the relative offsets within a
+ * vdev label. We must determine the label which is being
+ * updated and adjust our region accordingly.
+ */
+ label = vdev_label_number(vd->vdev_psize, offset);
+ start = vdev_label_offset(vd->vdev_psize, label, start);
+ end = vdev_label_offset(vd->vdev_psize, label, end);
+
+ if (zio->io_vd->vdev_guid == handler->zi_record.zi_guid &&
+ (offset >= start && offset <= end)) {
+ ret = error;
+ break;
+ }
+ }
+ rw_exit(&inject_lock);
+ return (ret);
+}
+
+
+int
+zio_handle_device_injection(vdev_t *vd, int error)
+{
+ inject_handler_t *handler;
+ int ret = 0;
+
+ rw_enter(&inject_lock, RW_READER);
+
+ for (handler = list_head(&inject_handlers); handler != NULL;
+ handler = list_next(&inject_handlers, handler)) {
+
+ /* Ignore label specific faults */
+ if (handler->zi_record.zi_start != 0)
+ continue;
+
+ if (vd->vdev_guid == handler->zi_record.zi_guid) {
+ if (handler->zi_record.zi_error == error) {
+ /*
+ * For a failed open, pretend like the device
+ * has gone away.
+ */
+ if (error == ENXIO)
+ vd->vdev_stat.vs_aux =
+ VDEV_AUX_OPEN_FAILED;
+ ret = error;
+ break;
+ }
+ if (handler->zi_record.zi_error == ENXIO) {
+ ret = EIO;
+ break;
+ }
+ }
+ }
+
+ rw_exit(&inject_lock);
+
+ return (ret);
+}
+
+/*
+ * Create a new handler for the given record. We add it to the list, adding
+ * a reference to the spa_t in the process. We increment zio_injection_enabled,
+ * which is the switch to trigger all fault injection.
+ */
+int
+zio_inject_fault(char *name, int flags, int *id, zinject_record_t *record)
+{
+ inject_handler_t *handler;
+ int error;
+ spa_t *spa;
+
+ /*
+ * If this is pool-wide metadata, make sure we unload the corresponding
+ * spa_t, so that the next attempt to load it will trigger the fault.
+ * We call spa_reset() to unload the pool appropriately.
+ */
+ if (flags & ZINJECT_UNLOAD_SPA)
+ if ((error = spa_reset(name)) != 0)
+ return (error);
+
+ if (!(flags & ZINJECT_NULL)) {
+ /*
+ * spa_inject_ref() will add an injection reference, which will
+ * prevent the pool from being removed from the namespace while
+ * still allowing it to be unloaded.
+ */
+ if ((spa = spa_inject_addref(name)) == NULL)
+ return (ENOENT);
+
+ handler = kmem_alloc(sizeof (inject_handler_t), KM_SLEEP);
+
+ rw_enter(&inject_lock, RW_WRITER);
+
+ *id = handler->zi_id = inject_next_id++;
+ handler->zi_spa = spa;
+ handler->zi_record = *record;
+ list_insert_tail(&inject_handlers, handler);
+ atomic_add_32(&zio_injection_enabled, 1);
+
+ rw_exit(&inject_lock);
+ }
+
+ /*
+ * Flush the ARC, so that any attempts to read this data will end up
+ * going to the ZIO layer. Note that this is a little overkill, but
+ * we don't have the necessary ARC interfaces to do anything else, and
+ * fault injection isn't a performance critical path.
+ */
+ if (flags & ZINJECT_FLUSH_ARC)
+ arc_flush(NULL);
+
+ return (0);
+}
+
+/*
+ * Returns the next record with an ID greater than that supplied to the
+ * function. Used to iterate over all handlers in the system.
+ */
+int
+zio_inject_list_next(int *id, char *name, size_t buflen,
+ zinject_record_t *record)
+{
+ inject_handler_t *handler;
+ int ret;
+
+ mutex_enter(&spa_namespace_lock);
+ rw_enter(&inject_lock, RW_READER);
+
+ for (handler = list_head(&inject_handlers); handler != NULL;
+ handler = list_next(&inject_handlers, handler))
+ if (handler->zi_id > *id)
+ break;
+
+ if (handler) {
+ *record = handler->zi_record;
+ *id = handler->zi_id;
+ (void) strncpy(name, spa_name(handler->zi_spa), buflen);
+ ret = 0;
+ } else {
+ ret = ENOENT;
+ }
+
+ rw_exit(&inject_lock);
+ mutex_exit(&spa_namespace_lock);
+
+ return (ret);
+}
+
+/*
+ * Clear the fault handler with the given identifier, or return ENOENT if none
+ * exists.
+ */
+int
+zio_clear_fault(int id)
+{
+ inject_handler_t *handler;
+ int ret;
+
+ rw_enter(&inject_lock, RW_WRITER);
+
+ for (handler = list_head(&inject_handlers); handler != NULL;
+ handler = list_next(&inject_handlers, handler))
+ if (handler->zi_id == id)
+ break;
+
+ if (handler == NULL) {
+ ret = ENOENT;
+ } else {
+ list_remove(&inject_handlers, handler);
+ spa_inject_delref(handler->zi_spa);
+ kmem_free(handler, sizeof (inject_handler_t));
+ atomic_add_32(&zio_injection_enabled, -1);
+ ret = 0;
+ }
+
+ rw_exit(&inject_lock);
+
+ return (ret);
+}
+
+void
+zio_inject_init(void)
+{
+ rw_init(&inject_lock, NULL, RW_DEFAULT, NULL);
+ list_create(&inject_handlers, sizeof (inject_handler_t),
+ offsetof(inject_handler_t, zi_link));
+}
+
+void
+zio_inject_fini(void)
+{
+ list_destroy(&inject_handlers);
+ rw_destroy(&inject_lock);
+}
git://git.camperquake.de / zfs.git / blobdiff