zed: mark disks as REMOVED when they are removed

ZED does not take any action for disk removal events if there is no
spare VDEV available. Added zpool_vdev_remove_wanted() in libzfs
and vdev_remove_wanted() in vdev.c to remove the VDEV through ZED
on removal event.  This means that if you are running zed and
remove a disk, it will be propertly marked as REMOVED.

Signed-off-by: Ameer Hamza <ahamza@ixsystems.com>

include/libzfs.h

@@ -307,6 +307,7 @@ extern int zpool_vdev_remove_cancel(zpool_handle_t *);
 extern int zpool_vdev_indirect_size(zpool_handle_t *, const char *, uint64_t *);
 extern int zpool_vdev_split(zpool_handle_t *, char *, nvlist_t **, nvlist_t *,
     splitflags_t);
+_LIBZFS_H int zpool_vdev_remove_wanted(zpool_handle_t *, const char *);
 
 extern int zpool_vdev_fault(zpool_handle_t *, uint64_t, vdev_aux_t);
 extern int zpool_vdev_degrade(zpool_handle_t *, uint64_t, vdev_aux_t);

include/os/linux/kernel/linux/blkdev_compat.h

@@ -256,6 +256,32 @@ bio_set_bi_error(struct bio *bio, int error)
 #define	BIO_END_IO(bio, error)		bio_endio(bio, error);
 #endif /* HAVE_1ARG_BIO_END_IO_T */
 
+/*
+ * 5.15 MACRO,
+ *   GD_DEAD
+ *
+ * 2.6.36 - 5.14 MACRO,
+ *   GENHD_FL_UP
+ *
+ * Check the disk status and return B_TRUE if alive
+ * otherwise B_FALSE
+ */
+static inline boolean_t
+zfs_check_disk_status(struct block_device *bdev)
+{
+#if defined(GENHD_FL_UP)
+	return (!!(bdev->bd_disk->flags & GENHD_FL_UP));
+#elif defined(GD_DEAD)
+	return (!test_bit(GD_DEAD, &bdev->bd_disk->state));
+#else
+/*
+ * This is encountered if neither GENHD_FL_UP nor GD_DEAD is available in
+ * the kernel - likely due to an MACRO change that needs to be chased down.
+ */
+#error "Unsupported kernel: no usable disk status check"
+#endif
+}
+
 /*
  * 4.1 API,
  * 3.10.0 CentOS 7.x API,

include/os/linux/spl/sys/Makefile.am

@@ -20,6 +20,7 @@ KERNEL_H = \
 	kmem.h \
 	kstat.h \
 	list.h \
+	misc.h \
 	mod_os.h \
 	mutex.h \
 	param.h \

include/os/linux/spl/sys/misc.h

@@ -0,0 +1,29 @@
+/*
+ * 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 https://opensource.org/licenses/CDDL-1.0.
+ * 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
+ */
+
+#ifndef _OS_LINUX_SPL_MISC_H
+#define	_OS_LINUX_SPL_MISC_H
+
+#include <linux/kobject.h>
+
+extern void spl_signal_kobj_evt(struct block_device *bdev);
+
+#endif

include/sys/spa.h

@@ -837,7 +837,7 @@ extern kmutex_t spa_namespace_lock;
 #define	SPA_CONFIG_UPDATE_POOL	0
 #define	SPA_CONFIG_UPDATE_VDEVS	1
 
-extern void spa_write_cachefile(spa_t *, boolean_t, boolean_t);
+extern void spa_write_cachefile(spa_t *, boolean_t, boolean_t, boolean_t);
 extern void spa_config_load(void);
 extern nvlist_t *spa_all_configs(uint64_t *);
 extern void spa_config_set(spa_t *spa, nvlist_t *config);

include/sys/vdev.h

@@ -147,6 +147,7 @@ extern int vdev_degrade(spa_t *spa, uint64_t guid, vdev_aux_t aux);
 extern int vdev_online(spa_t *spa, uint64_t guid, uint64_t flags,
     vdev_state_t *);
 extern int vdev_offline(spa_t *spa, uint64_t guid, uint64_t flags);
+extern int vdev_remove_wanted(spa_t *spa, uint64_t guid);
 extern void vdev_clear(spa_t *spa, vdev_t *vd);
 
 extern boolean_t vdev_is_dead(vdev_t *vd);
@@ -189,6 +190,8 @@ typedef enum vdev_config_flag {
 	VDEV_CONFIG_MISSING = 1 << 4
 } vdev_config_flag_t;
 
+extern void vdev_post_kobj_evt(vdev_t *vd);
+extern void vdev_clear_kobj_evt(vdev_t *vd);
 extern void vdev_top_config_generate(spa_t *spa, nvlist_t *config);
 extern nvlist_t *vdev_config_generate(spa_t *spa, vdev_t *vd,
     boolean_t getstats, vdev_config_flag_t flags);

include/sys/vdev_impl.h

@@ -69,6 +69,7 @@ extern uint32_t zfs_vdev_async_write_max_active;
  * Virtual device operations
  */
 typedef int	vdev_init_func_t(spa_t *spa, nvlist_t *nv, void **tsd);
+typedef void	vdev_kobj_post_evt_func_t(vdev_t *vd);
 typedef void	vdev_fini_func_t(vdev_t *vd);
 typedef int	vdev_open_func_t(vdev_t *vd, uint64_t *size, uint64_t *max_size,
     uint64_t *ashift, uint64_t *pshift);
@@ -123,6 +124,7 @@ typedef const struct vdev_ops {
 	vdev_config_generate_func_t	*vdev_op_config_generate;
 	vdev_nparity_func_t		*vdev_op_nparity;
 	vdev_ndisks_func_t		*vdev_op_ndisks;
+	vdev_kobj_post_evt_func_t	*vdev_op_kobj_evt_post;
 	char				vdev_op_type[16];
 	boolean_t			vdev_op_leaf;
 } vdev_ops_t;
@@ -435,6 +437,7 @@ struct vdev {
 	boolean_t	vdev_isl2cache;	/* was a l2cache device		*/
 	boolean_t	vdev_copy_uberblocks;  /* post expand copy uberblocks */
 	boolean_t	vdev_resilver_deferred;  /* resilver deferred */
+	boolean_t	vdev_kobj_flag; /* kobj event record */
 	vdev_queue_t	vdev_queue;	/* I/O deadline schedule queue	*/
 	vdev_cache_t	vdev_cache;	/* physical block cache		*/
 	spa_aux_vdev_t	*vdev_aux;	/* for l2cache and spares vdevs	*/

include/sys/zfs_context.h

@@ -51,6 +51,7 @@ extern "C" {
 #include <sys/kmem.h>
 #include <sys/kmem_cache.h>
 #include <sys/vmem.h>
+#include <sys/misc.h>
 #include <sys/taskq.h>
 #include <sys/param.h>
 #include <sys/disp.h>