/* * Copyright (C) 2004 SUSE LINUX Products GmbH. All rights reserved. * Copyright (C) 2004 Red Hat, Inc. All rights reserved. * * This file is released under the GPL. * * Multipath support for EMC CLARiiON AX/CX-series hardware. */ #include "dm.h" #include "dm-hw-handler.h" #include <scsi/scsi.h> #include <scsi/scsi_cmnd.h> #define DM_MSG_PREFIX "multipath emc" struct emc_handler { spinlock_t lock; /* Whether we should send the short trespass command (FC-series) * or the long version (default for AX/CX CLARiiON arrays). */ unsigned short_trespass; /* Whether or not to honor SCSI reservations when initiating a * switch-over. Default: Don't. */ unsigned hr; unsigned char sense[SCSI_SENSE_BUFFERSIZE]; }; #define TRESPASS_PAGE 0x22 #define EMC_FAILOVER_TIMEOUT (60 * HZ) /* Code borrowed from dm-lsi-rdac by Mike Christie */ static inline void free_bio(struct bio *bio) { __free_page(bio->bi_io_vec[0].bv_page); bio_put(bio); } static int emc_endio(struct bio *bio, unsigned int bytes_done, int error) { struct dm_path *path = bio->bi_private; if (bio->bi_size) return 1; /* We also need to look at the sense keys here whether or not to * switch to the next PG etc. * * For now simple logic: either it works or it doesn't. */ if (error) dm_pg_init_complete(path, MP_FAIL_PATH); else dm_pg_init_complete(path, 0); /* request is freed in block layer */ free_bio(bio); return 0; } static struct bio *get_failover_bio(struct dm_path *path, unsigned data_size) { struct bio *bio; struct page *page; bio = bio_alloc(GFP_ATOMIC, 1); if (!bio) { DMERR("get_failover_bio: bio_alloc() failed."); return NULL; } bio->bi_rw |= (1 << BIO_RW); bio->bi_bdev = path->dev->bdev; bio->bi_sector = 0; bio->bi_private = path; bio->bi_end_io = emc_endio; page = alloc_page(GFP_ATOMIC); if (!page) { DMERR("get_failover_bio: alloc_page() failed."); bio_put(bio); return NULL; } if (bio_add_page(bio, page, data_size, 0) != data_size) { DMERR("get_failover_bio: alloc_page() failed."); __free_page(page); bio_put(bio); return NULL; } return bio; } static struct request *get_failover_req(struct emc_handler *h, struct bio *bio, struct dm_path *path) { struct request *rq; struct block_device *bdev = bio->bi_bdev; struct request_queue *q = bdev_get_queue(bdev); /* FIXME: Figure out why it fails with GFP_ATOMIC. */ rq = blk_get_request(q, WRITE, __GFP_WAIT); if (!rq) { DMERR("get_failover_req: blk_get_request failed"); return NULL; } rq->bio = rq->biotail = bio; blk_rq_bio_prep(q, rq, bio); rq->rq_disk = bdev->bd_contains->bd_disk; /* bio backed don't set data */ rq->buffer = rq->data = NULL; /* rq data_len used for pc cmd's request_bufflen */ rq->data_len = bio->bi_size; rq->sense = h->sense; memset(rq->sense, 0, SCSI_SENSE_BUFFERSIZE); rq->sense_len = 0; memset(&rq->cmd, 0, BLK_MAX_CDB); rq->timeout = EMC_FAILOVER_TIMEOUT; rq->cmd_type = REQ_TYPE_BLOCK_PC; rq->cmd_flags |= REQ_FAILFAST | REQ_NOMERGE; return rq; } static struct request *emc_trespass_get(struct emc_handler *h, struct dm_path *path) { struct bio *bio; struct request *rq; unsigned char *page22; unsigned char long_trespass_pg[] = { 0, 0, 0, 0, TRESPASS_PAGE, /* Page code */ 0x09, /* Page length - 2 */ h->hr ? 0x01 : 0x81, /* Trespass code + Honor reservation bit */ 0xff, 0xff, /* Trespass target */ 0, 0, 0, 0, 0, 0 /* Reserved bytes / unknown */ }; unsigned char short_trespass_pg[] = { 0, 0, 0, 0, TRESPASS_PAGE, /* Page code */ 0x02, /* Page length - 2 */ h->hr ? 0x01 : 0x81, /* Trespass code + Honor reservation bit */ 0xff, /* Trespass target */ }; unsigned data_size = h->short_trespass ? sizeof(short_trespass_pg) : sizeof(long_trespass_pg); /* get bio backing */ if (data_size > PAGE_SIZE) /* this should never happen */ return NULL; bio = get_failover_bio(path, data_size); if (!bio) { DMERR("emc_trespass_get: no bio"); return NULL; } page22 = (unsigned char *)bio_data(bio); memset(page22, 0, data_size); memcpy(page22, h->short_trespass ? short_trespass_pg : long_trespass_pg, data_size); /* get request for block layer packet command */ rq = get_failover_req(h, bio, path); if (!rq) { DMERR("emc_trespass_get: no rq"); free_bio(bio); return NULL; } /* Prepare the command. */ rq->cmd[0] = MODE_SELECT; rq->cmd[1] = 0x10; rq->cmd[4] = data_size; rq->cmd_len = COMMAND_SIZE(rq->cmd[0]); return rq; } static void emc_pg_init(struct hw_handler *hwh, unsigned bypassed, struct dm_path *path) { struct request *rq; struct request_queue *q = bdev_get_queue(path->dev->bdev); /* * We can either blindly init the pg (then look at the sense), * or we can send some commands to get the state here (then * possibly send the fo cmnd), or we can also have the * initial state passed into us and then get an update here. */ if (!q) { DMINFO("emc_pg_init: no queue"); goto fail_path; } /* FIXME: The request should be pre-allocated. */ rq = emc_trespass_get(hwh->context, path); if (!rq) { DMERR("emc_pg_init: no rq"); goto fail_path; } DMINFO("emc_pg_init: sending switch-over command"); elv_add_request(q, rq, ELEVATOR_INSERT_FRONT, 1); return; fail_path: dm_pg_init_complete(path, MP_FAIL_PATH); } static struct emc_handler *alloc_emc_handler(void) { struct emc_handler *h = kmalloc(sizeof(*h), GFP_KERNEL); if (h) { memset(h, 0, sizeof(*h)); spin_lock_init(&h->lock); } return h; } static int emc_create(struct hw_handler *hwh, unsigned argc, char **argv) { struct emc_handler *h; unsigned hr, short_trespass; if (argc == 0) { /* No arguments: use defaults */ hr = 0; short_trespass = 0; } else if (argc != 2) { DMWARN("incorrect number of arguments"); return -EINVAL; } else { if ((sscanf(argv[0], "%u", &short_trespass) != 1) || (short_trespass > 1)) { DMWARN("invalid trespass mode selected"); return -EINVAL; } if ((sscanf(argv[1], "%u", &hr) != 1) || (hr > 1)) { DMWARN("invalid honor reservation flag selected"); return -EINVAL; } } h = alloc_emc_handler(); if (!h) return -ENOMEM; hwh->context = h; if ((h->short_trespass = short_trespass)) DMWARN("short trespass command will be send"); else DMWARN("long trespass command will be send"); if ((h->hr = hr)) DMWARN("honor reservation bit will be set"); else DMWARN("honor reservation bit will not be set (default)"); return 0; } static void emc_destroy(struct hw_handler *hwh) { struct emc_handler *h = (struct emc_handler *) hwh->context; kfree(h); hwh->context = NULL; } static unsigned emc_error(struct hw_handler *hwh, struct bio *bio) { /* FIXME: Patch from axboe still missing */ #if 0 int sense; if (bio->bi_error & BIO_SENSE) { sense = bio->bi_error & 0xffffff; /* sense key / asc / ascq */ if (sense == 0x020403) { /* LUN Not Ready - Manual Intervention Required * indicates this is a passive path. * * FIXME: However, if this is seen and EVPD C0 * indicates that this is due to a NDU in * progress, we should set FAIL_PATH too. * This indicates we might have to do a SCSI * inquiry in the end_io path. Ugh. */ return MP_BYPASS_PG | MP_RETRY_IO; } else if (sense == 0x052501) { /* An array based copy is in progress. Do not * fail the path, do not bypass to another PG, * do not retry. Fail the IO immediately. * (Actually this is the same conclusion as in * the default handler, but lets make sure.) */ return 0; } else if (sense == 0x062900) { /* Unit Attention Code. This is the first IO * to the new path, so just retry. */ return MP_RETRY_IO; } } #endif /* Try default handler */ return dm_scsi_err_handler(hwh, bio); } static struct hw_handler_type emc_hwh = { .name = "emc", .module = THIS_MODULE, .create = emc_create, .destroy = emc_destroy, .pg_init = emc_pg_init, .error = emc_error, }; static int __init dm_emc_init(void) { int r = dm_register_hw_handler(&emc_hwh); if (r < 0) DMERR("register failed %d", r); DMINFO("version 0.0.3 loaded"); return r; } static void __exit dm_emc_exit(void) { int r = dm_unregister_hw_handler(&emc_hwh); if (r < 0) DMERR("unregister failed %d", r); } module_init(dm_emc_init); module_exit(dm_emc_exit); MODULE_DESCRIPTION(DM_NAME " EMC CX/AX/FC-family multipath"); MODULE_AUTHOR("Lars Marowsky-Bree <lmb@suse.de>"); MODULE_LICENSE("GPL");