/* * MARS Long Distance Replication Software * * This file is part of MARS project: http://schoebel.github.io/mars/ * * Copyright (C) 2010-2014 Thomas Schoebel-Theuer * Copyright (C) 2011-2014 1&1 Internet AG * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License along * with this program; if not, write to the Free Software Foundation, Inc., * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. */ /* Interface to a Linux device. * 1 Input, 0 Outputs. */ //#define BRICK_DEBUGGING //#define MARS_DEBUGGING //#define IO_DEBUGGING #define REQUEST_MERGING //#define ALWAYS_UNPLUG false // FIXME: does not work! single requests left over! #define ALWAYS_UNPLUG true #define ALWAYS_UNPLUG_FROM_EXTERNAL true #define PREFETCH_LEN PAGE_SIZE //#define FRONT_MERGE // FIXME: this does not work. //#define MODIFY_READAHEAD // don't use it, otherwise sequential IO will suffer // low-level device parameters #define USE_MAX_SECTORS (MARS_MAX_SEGMENT_SIZE >> 9) #define USE_MAX_PHYS_SEGMENTS (MARS_MAX_SEGMENT_SIZE >> 9) #define USE_MAX_SEGMENT_SIZE MARS_MAX_SEGMENT_SIZE #define USE_LOGICAL_BLOCK_SIZE 512 #define USE_SEGMENT_BOUNDARY (PAGE_SIZE-1) #define USE_CONGESTED_FN //#define DENY_READA #include #include #include #include #include #include #include #include "mars.h" #include "lib_limiter.h" // remove_this #ifdef bio_end_sector #define HAS_VOID_RELEASE #endif #ifdef __bvec_iter_bvec #define HAS_BVEC_ITER #endif /* adaptation to 4246a0b63bd8f56a1469b12eafeb875b1041a451 and 8ae126660fddbeebb9251a174e6fa45b6ad8f932 */ #ifndef bio_io_error #define HAS_BI_ERROR #else #define HAS_MERGE_BVEC #endif // end_remove_this ///////////////////////// global tuning //////////////////////// int if_nr_requests = 1024; int if_throttle_start_size = 0; // in kb EXPORT_SYMBOL_GPL(if_throttle_start_size); struct mars_limiter if_throttle = { .lim_max_rate = 5000, }; EXPORT_SYMBOL_GPL(if_throttle); ///////////////////////// own type definitions //////////////////////// #include "mars_if.h" #define IF_HASH_MAX (PAGE_SIZE / sizeof(struct if_hash_anchor)) #define IF_HASH_CHUNK (PAGE_SIZE * 32) struct if_hash_anchor { spinlock_t hash_lock; struct list_head hash_anchor; }; ///////////////////////// own static definitions //////////////////////// // TODO: check bounds, ensure that free minor numbers are recycled static int device_minor = 0; //////////////// object / aspect constructors / destructors /////////////// ///////////////////////// linux operations //////////////////////// #ifdef part_stat_lock static void _if_start_io_acct(struct if_input *input, struct bio_wrapper *biow) { struct bio *bio = biow->bio; const int rw = bio_data_dir(bio); const int cpu = part_stat_lock(); (void)cpu; part_round_stats(cpu, &input->disk->part0); part_stat_inc(cpu, &input->disk->part0, ios[rw]); // remove_this #ifdef HAS_BVEC_ITER // end_remove_this part_stat_add(cpu, &input->disk->part0, sectors[rw], bio->bi_iter.bi_size >> 9); // remove_this #else part_stat_add(cpu, &input->disk->part0, sectors[rw], bio->bi_size >> 9); #endif // end_remove_this part_inc_in_flight(&input->disk->part0, rw); part_stat_unlock(); biow->start_time = jiffies; } static void _if_end_io_acct(struct if_input *input, struct bio_wrapper *biow) { unsigned long duration = jiffies - biow->start_time; struct bio *bio = biow->bio; const int rw = bio_data_dir(bio); const int cpu = part_stat_lock(); (void)cpu; part_stat_add(cpu, &input->disk->part0, ticks[rw], duration); part_round_stats(cpu, &input->disk->part0); part_dec_in_flight(&input->disk->part0, rw); part_stat_unlock(); } #else // part_stat_lock #define _if_start_io_acct(...) do {} while (0) #define _if_end_io_acct(...) do {} while (0) #endif /* callback */ static void if_endio(struct generic_callback *cb) { struct if_mref_aspect *mref_a = cb->cb_private; struct if_input *input; int k; int rw; int error; LAST_CALLBACK(cb); if (unlikely(!mref_a || !mref_a->object)) { MARS_FAT("mref_a = %p mref = %p, something is very wrong here!\n", mref_a, mref_a->object); return; } input = mref_a->input; CHECK_PTR(input, err); mars_trace(mref_a->object, "if_endio"); mars_log_trace(mref_a->object); rw = mref_a->object->ref_rw; MARS_IO("rw = %d bio_count = %d\n", rw, mref_a->bio_count); for (k = 0; k < mref_a->bio_count; k++) { struct bio_wrapper *biow; struct bio *bio; biow = mref_a->orig_biow[k]; mref_a->orig_biow[k] = NULL; CHECK_PTR(biow, err); CHECK_ATOMIC(&biow->bi_comp_cnt, 1); if (!atomic_dec_and_test(&biow->bi_comp_cnt)) { continue; } bio = biow->bio; CHECK_PTR_NULL(bio, err); _if_end_io_acct(input, biow); error = CALLBACK_ERROR(mref_a->object); if (unlikely(error < 0)) { // remove_this #ifdef HAS_BVEC_ITER // end_remove_this int bi_size = bio->bi_iter.bi_size; // remove_this #else int bi_size = bio->bi_size; #endif // end_remove_this MARS_ERR("NYI: error=%d RETRY LOGIC %u\n", error, bi_size); } else { // bio conventions are slightly different... error = 0; // remove_this #ifdef HAS_BVEC_ITER // end_remove_this bio->bi_iter.bi_size = 0; // remove_this #else bio->bi_size = 0; #endif // end_remove_this } MARS_IO("calling end_io() rw = %d error = %d\n", rw, error); // remove_this #ifdef HAS_BI_ERROR // end_remove_this bio->bi_error = error; bio_endio(bio); // remove_this #else bio_endio(bio, error); #endif // end_remove_this bio_put(bio); brick_mem_free(biow); } atomic_dec(&input->flying_count); if (rw) { atomic_dec(&input->write_flying_count); } else { atomic_dec(&input->read_flying_count); } #ifdef IO_DEBUGGING { struct if_brick *brick = input->brick; char *txt = brick->ops->brick_statistics(brick, false); MARS_IO("%s", txt); brick_string_free(txt); } #endif MARS_IO("finished.\n"); return; err: MARS_FAT("error in callback, giving up\n"); } /* Kick off plugged mrefs */ static void _if_unplug(struct if_input *input) { //struct if_brick *brick = input->brick; LIST_HEAD(tmp_list); unsigned long flags; #ifdef CONFIG_MARS_DEBUG might_sleep(); #endif MARS_IO("plugged_count = %d\n", atomic_read(&input->plugged_count)); down(&input->kick_sem); traced_lock(&input->req_lock, flags); #ifdef USE_TIMER del_timer(&input->timer); #endif if (!list_empty(&input->plug_anchor)) { // move over the whole list list_replace_init(&input->plug_anchor, &tmp_list); atomic_set(&input->plugged_count, 0); } traced_unlock(&input->req_lock, flags); up(&input->kick_sem); while (!list_empty(&tmp_list)) { struct if_mref_aspect *mref_a; struct mref_object *mref; int hash_index; unsigned long flags; mref_a = container_of(tmp_list.next, struct if_mref_aspect, plug_head); list_del_init(&mref_a->plug_head); hash_index = mref_a->hash_index; traced_lock(&input->hash_table[hash_index].hash_lock, flags); list_del_init(&mref_a->hash_head); traced_unlock(&input->hash_table[hash_index].hash_lock, flags); mref = mref_a->object; if (unlikely(mref_a->current_len > mref_a->max_len)) { MARS_ERR("request len %d > %d\n", mref_a->current_len, mref_a->max_len); } mref->ref_len = mref_a->current_len; mars_trace(mref, "if_unplug"); atomic_inc(&input->flying_count); atomic_inc(&input->total_fire_count); if (mref->ref_rw) { atomic_inc(&input->write_flying_count); } else { atomic_inc(&input->read_flying_count); } if (mref->ref_skip_sync) atomic_inc(&input->total_skip_sync_count); GENERIC_INPUT_CALL(input, mref_io, mref); GENERIC_INPUT_CALL(input, mref_put, mref); } #ifdef IO_DEBUGGING { struct if_brick *brick = input->brick; char *txt = brick->ops->brick_statistics(brick, false); MARS_IO("%s", txt); brick_string_free(txt); } #endif } #ifndef BLK_MAX_REQUEST_COUNT #ifdef USE_TIMER static void if_timer(unsigned long data) { MARS_IO("\n"); _if_unplug((void*)data); } #endif #endif // BLK_MAX_REQUEST_COUNT /* accept a linux bio, convert to mref and call buf_io() on it. */ static // remove_this /* see dece16353ef47d8d33f5302bc158072a9d65e26f */ #ifdef BLK_QC_T_NONE // end_remove_this blk_qc_t if_make_request(struct request_queue *q, struct bio *bio) // remove_this #elif defined(BIO_CPU_AFFINE) int if_make_request(struct request_queue *q, struct bio *bio) #else void if_make_request(struct request_queue *q, struct bio *bio) #endif { struct if_input *input = q->queuedata; struct if_brick *brick = input->brick; /* Original flags of the source bio */ const int rw = bio_data_dir(bio); const int sectors = bio_sectors(bio); // adapt to different kernel versions (TBD: improve) #if defined(BIO_RW_RQ_MASK) || defined(BIO_FLUSH) const bool ahead = bio_rw_flagged(bio, BIO_RW_AHEAD) && rw == READ; const bool barrier = bio_rw_flagged(bio, BIO_RW_BARRIER); const bool syncio = bio_rw_flagged(bio, BIO_RW_SYNCIO); const bool unplug = bio_rw_flagged(bio, BIO_RW_UNPLUG); const bool meta = bio_rw_flagged(bio, BIO_RW_META); const bool discard = bio_rw_flagged(bio, BIO_RW_DISCARD); const bool noidle = bio_rw_flagged(bio, BIO_RW_NOIDLE); #elif defined(REQ_FLUSH) && defined(REQ_SYNC) #define _flagged(x) (bio->bi_rw & (x)) const bool ahead = _flagged(REQ_RAHEAD) && rw == READ; const bool barrier = _flagged(REQ_FLUSH); const bool syncio = _flagged(REQ_SYNC); const bool unplug = false; const bool meta = _flagged(REQ_META); const bool discard = _flagged(REQ_DISCARD); const bool noidle = _flagged(REQ_THROTTLED); #else #error Cannot decode the bio flags #endif const int prio = bio_prio(bio); /* Transform into MARS flags */ const int ref_prio = (prio == IOPRIO_CLASS_RT || (meta | syncio)) ? MARS_PRIO_HIGH : (prio == IOPRIO_CLASS_IDLE) ? MARS_PRIO_LOW : MARS_PRIO_NORMAL; const bool do_unplug = ALWAYS_UNPLUG | unplug | noidle; const bool do_skip_sync = brick->skip_sync && !(barrier | syncio); struct bio_wrapper *biow; struct mref_object *mref = NULL; struct if_mref_aspect *mref_a; // remove_this #ifdef HAS_BVEC_ITER // end_remove_this struct bio_vec bvec; struct bvec_iter i; loff_t pos = ((loff_t)bio->bi_iter.bi_sector) << 9; // TODO: make dynamic int total_len = bio->bi_iter.bi_size; // remove_this #else struct bio_vec *bvec; int i; loff_t pos = ((loff_t)bio->bi_sector) << 9; // TODO: make dynamic int total_len = bio->bi_size; #endif // end_remove_this bool assigned = false; int error = -EINVAL; bind_to_channel(brick->say_channel, current); MARS_IO("bio %p " "size = %d " "rw = %d " "sectors = %d " "ahead = %d " "barrier = %d " "syncio = %d " "unplug = %d " "meta = %d " "discard = %d " "noidle = %d " "prio = %d " "pos = %lldd " "total_len = %d\n", bio, bio->bi_size, rw, sectors, ahead, barrier, syncio, unplug, meta, discard, noidle, prio, pos, total_len); might_sleep(); if (unlikely(!sectors)) { _if_unplug(input); /* THINK: usually this happens only at write barriers. * We have no "barrier" operation in MARS, since * callback semantics should always denote * "writethrough accomplished". * In case of exceptional semantics, we need to do * something here. For now, we do just nothing. */ // remove_this #ifdef HAS_BI_ERROR // end_remove_this error = 0; bio->bi_error = error; bio_endio(bio); // remove_this #else bio_endio(bio, error); #endif // end_remove_this goto done; } // throttling of too big write requests if (rw && if_throttle_start_size > 0) { int kb = (total_len + 512) / 1024; if (kb >= if_throttle_start_size) mars_limit_sleep(&if_throttle, kb); } #ifdef DENY_READA // provisinary -- we should introduce an equivalent of READA also to the MARS infrastructure if (ahead) { atomic_inc(&input->total_reada_count); // remove_this #ifdef HAS_BI_ERROR // end_remove_this bio->bi_error = -EWOULDBLOCK; bio_endio(bio); // remove_this #else bio_endio(bio, -EWOULDBLOCK); #endif // end_remove_this error = 0; goto done; } #else (void)ahead; // shut up gcc #endif if (unlikely(discard)) { // NYI error = 0; // remove_this #ifdef HAS_BI_ERROR // end_remove_this bio->bi_error = error; bio_endio(bio); // remove_this #else bio_endio(bio, error); #endif // end_remove_this goto done; } biow = brick_mem_alloc(sizeof(struct bio_wrapper)); CHECK_PTR(biow, err); biow->bio = bio; atomic_set(&biow->bi_comp_cnt, 0); if (rw) { atomic_inc(&input->total_write_count); } else { atomic_inc(&input->total_read_count); } _if_start_io_acct(input, biow); /* Get a reference to the bio. * Will be released after bio_endio(). */ bio_get(bio); /* FIXME: THIS IS PROVISIONARY (use event instead) */ while (unlikely(!brick->power.led_on)) { brick_msleep(100); } down(&input->kick_sem); bio_for_each_segment(bvec, bio, i) { // remove_this #ifdef HAS_BVEC_ITER // end_remove_this struct page *page = bvec.bv_page; int bv_len = bvec.bv_len; int offset = bvec.bv_offset; // remove_this #else struct page *page = bvec->bv_page; int bv_len = bvec->bv_len; int offset = bvec->bv_offset; #endif // end_remove_this void *data; #ifdef ARCH_HAS_KMAP #error FIXME: the current infrastructure cannot deal with HIGHMEM / kmap() #endif data = page_address(page); MARS_IO("page = %p data = %p\n", page, data); error = -EINVAL; if (unlikely(!data)) break; data += offset; while (bv_len > 0) { struct list_head *tmp; int hash_index; int this_len = 0; unsigned long flags; mref = NULL; mref_a = NULL; MARS_IO("rw = %d i = %d pos = %lld bv_page = %p bv_offset = %d data = %p bv_len = %d\n", rw, i, pos, bvec->bv_page, bvec->bv_offset, data, bv_len); hash_index = (pos / IF_HASH_CHUNK) % IF_HASH_MAX; #ifdef REQUEST_MERGING traced_lock(&input->hash_table[hash_index].hash_lock, flags); for (tmp = input->hash_table[hash_index].hash_anchor.next; tmp != &input->hash_table[hash_index].hash_anchor; tmp = tmp->next) { struct if_mref_aspect *tmp_a; struct mref_object *tmp_mref; int i; tmp_a = container_of(tmp, struct if_mref_aspect, hash_head); tmp_mref = tmp_a->object; if (tmp_a->orig_page != page || tmp_mref->ref_rw != rw || tmp_a->bio_count >= MAX_BIO || tmp_a->current_len + bv_len > tmp_a->max_len) { continue; } if (tmp_mref->ref_data + tmp_a->current_len == data) { goto merge_end; #ifdef FRONT_MERGE // FIXME: this cannot work. ref_data must never be changed. pre-allocate from offset 0 instead. } else if (data + bv_len == tmp_mref->ref_data) { goto merge_front; #endif } continue; #ifdef FRONT_MERGE // FIXME: this cannot work. ref_data must never be changed. pre-allocate from offset 0 instead. merge_front: tmp_mref->ref_data = data; #endif merge_end: tmp_a->current_len += bv_len; mref = tmp_mref; mref_a = tmp_a; this_len = bv_len; if (!do_skip_sync) { mref->ref_skip_sync = false; } for (i = 0; i < mref_a->bio_count; i++) { if (mref_a->orig_biow[i]->bio == bio) { goto unlock; } } CHECK_ATOMIC(&biow->bi_comp_cnt, 0); atomic_inc(&biow->bi_comp_cnt); mref_a->orig_biow[mref_a->bio_count++] = biow; assigned = true; goto unlock; } // foreach hash collision list member unlock: traced_unlock(&input->hash_table[hash_index].hash_lock, flags); #endif if (!mref) { int prefetch_len; error = -ENOMEM; mref = if_alloc_mref(brick); if (unlikely(!mref)) { up(&input->kick_sem); goto err; } mref_a = if_mref_get_aspect(brick, mref); if (unlikely(!mref_a)) { up(&input->kick_sem); goto err; } #ifdef PREFETCH_LEN prefetch_len = PREFETCH_LEN - offset; #if 1 // TODO: this restriction is too strong to be useful for performance boosts. Do better. if (prefetch_len > total_len) { prefetch_len = total_len; } #endif if (pos + prefetch_len > brick->dev_size) { prefetch_len = brick->dev_size - pos; } if (prefetch_len < bv_len) { prefetch_len = bv_len; } #else prefetch_len = bv_len; #endif SETUP_CALLBACK(mref, if_endio, mref_a); mref_a->input = input; mref->ref_rw = mref->ref_may_write = rw; mref->ref_pos = pos; mref->ref_len = prefetch_len; mref->ref_data = data; // direct IO mref->ref_prio = ref_prio; mref_a->orig_page = page; error = GENERIC_INPUT_CALL(input, mref_get, mref); if (unlikely(error < 0)) { up(&input->kick_sem); goto err; } mars_trace(mref, "if_start"); this_len = mref->ref_len; // now may be shorter than originally requested. mref_a->max_len = this_len; if (this_len > bv_len) { this_len = bv_len; } mref_a->current_len = this_len; if (rw) { atomic_inc(&input->total_mref_write_count); } else { atomic_inc(&input->total_mref_read_count); } CHECK_ATOMIC(&biow->bi_comp_cnt, 0); atomic_inc(&biow->bi_comp_cnt); mref_a->orig_biow[0] = biow; mref_a->bio_count = 1; assigned = true; /* When a bio with multiple biovecs is split into * multiple mrefs, only the last one should be * working in synchronous writethrough mode. */ mref->ref_skip_sync = true; // remove_this #ifdef HAS_BVEC_ITER // end_remove_this if (!do_skip_sync && i.bi_idx + 1 >= bio->bi_iter.bi_idx) { mref->ref_skip_sync = false; } // remove_this #else if (!do_skip_sync && i + 1 >= bio->bi_vcnt) { mref->ref_skip_sync = false; } #endif // end_remove_this atomic_inc(&input->plugged_count); mref_a->hash_index = hash_index; traced_lock(&input->hash_table[hash_index].hash_lock, flags); list_add_tail(&mref_a->hash_head, &input->hash_table[hash_index].hash_anchor); traced_unlock(&input->hash_table[hash_index].hash_lock, flags); traced_lock(&input->req_lock, flags); list_add_tail(&mref_a->plug_head, &input->plug_anchor); traced_unlock(&input->req_lock, flags); } // !mref pos += this_len; data += this_len; bv_len -= this_len; total_len -= this_len; } // while bv_len > 0 } // foreach bvec up(&input->kick_sem); if (likely(!total_len)) { error = 0; } else { MARS_ERR("bad rest len = %d\n", total_len); } err: #ifdef IO_DEBUGGING { char *txt = brick->ops->brick_statistics(brick, false); MARS_IO("%s", txt); brick_string_free(txt); } #endif if (error < 0) { MARS_ERR("cannot submit request from bio, status=%d\n", error); if (!assigned) { // remove_this #ifdef HAS_BI_ERROR // end_remove_this bio->bi_error = error; bio_endio(bio); // remove_this #else bio_endio(bio, error); #endif // end_remove_this } } if (do_unplug || (brick && brick->max_plugged > 0 && atomic_read(&input->plugged_count) > brick->max_plugged)) { _if_unplug(input); } #ifdef USE_TIMER else { unsigned long flags; traced_lock(&input->req_lock, flags); if (timer_pending(&input->timer)) { del_timer(&input->timer); } input->timer.function = if_timer; input->timer.data = (unsigned long)input; input->timer.expires = jiffies + USE_TIMER; add_timer(&input->timer); traced_unlock(&input->req_lock, flags); } #endif done: remove_binding_from(brick->say_channel, current); // remove_this /* see dece16353ef47d8d33f5302bc158072a9d65e26f */ #ifdef BLK_QC_T_NONE // end_remove_this return BLK_QC_T_NONE; // remove_this #elif defined(BIO_CPU_AFFINE) return error; #else return; #endif } #ifndef BLK_MAX_REQUEST_COUNT //static void if_unplug(struct request_queue *q) { struct if_input *input = q->queuedata; int was_plugged = 1; #if 1 spin_lock_irq(q->queue_lock); was_plugged = blk_remove_plug(q); spin_unlock_irq(q->queue_lock); #else queue_flag_clear_unlocked(QUEUE_FLAG_PLUGGED, q); #endif was_plugged += atomic_read(&input->plugged_count); MARS_IO("block layer called UNPLUG was_plugged = %d\n", was_plugged); if (ALWAYS_UNPLUG_FROM_EXTERNAL || was_plugged) { _if_unplug(input); } } #endif //static int mars_congested(void *data, int bdi_bits) { struct if_input *input = data; int ret = 0; #ifdef WB_STAT_BATCH /* changed by 4452226ea276e74fc3e252c88d9bb7e8f8e44bf0 */ if (bdi_bits & (1 << WB_sync_congested) && atomic_read(&input->read_flying_count) > 0) { ret |= (1 << WB_sync_congested); } if (bdi_bits & (1 << WB_async_congested) && atomic_read(&input->write_flying_count) > 0) { ret |= (1 << WB_async_congested); } #else /* old code */ if (bdi_bits & (1 << BDI_sync_congested) && atomic_read(&input->read_flying_count) > 0) { ret |= (1 << BDI_sync_congested); } if (bdi_bits & (1 << BDI_async_congested) && atomic_read(&input->write_flying_count) > 0) { ret |= (1 << BDI_async_congested); } #endif return ret; } // remove_this #ifdef HAS_MERGE_BVEC static int mars_merge_bvec(struct request_queue *q, struct bvec_merge_data *bvm, struct bio_vec *bvec) { unsigned int bio_size = bvm->bi_size; if (!bio_size) { return bvec->bv_len; } return 128; } #endif // end_remove_this static loff_t if_get_capacity(struct if_brick *brick) { /* Don't read always, read only when unknown. * brick->dev_size may be different from underlying sizes, * e.g. when the size symlink indicates a logically smaller * device than physically. */ if (brick->dev_size <= 0) { struct mars_info info = {}; struct if_input *input = brick->inputs[0]; int status; status = GENERIC_INPUT_CALL(input, mars_get_info, &info); if (unlikely(status < 0)) { MARS_ERR("cannot get device info, status=%d\n", status); return 0; } MARS_INF("determined default capacity: %lld bytes\n", info.current_size); brick->dev_size = info.current_size; } return brick->dev_size; } static void if_set_capacity(struct if_input *input, loff_t capacity) { CHECK_PTR(input->disk, done); CHECK_PTR(input->disk->disk_name, done); MARS_INF("new capacity of '%s': %lld bytes\n", input->disk->disk_name, capacity); input->capacity = capacity; set_capacity(input->disk, capacity >> 9); if (likely(input->bdev && input->bdev->bd_inode)) { i_size_write(input->bdev->bd_inode, capacity); } done:; } static const struct block_device_operations if_blkdev_ops; static int if_switch(struct if_brick *brick) { struct if_input *input = brick->inputs[0]; struct request_queue *q; struct gendisk *disk; int minor; int status = 0; down(&brick->switch_sem); // brick is in operation if (brick->power.button && brick->power.led_on) { loff_t capacity; capacity = if_get_capacity(brick); if (capacity > 0 && capacity != input->capacity) { MARS_INF("changing capacity from %lld to %lld\n", (long long)input->capacity, (long long)capacity); if_set_capacity(input, capacity); } } // brick should be switched on if (brick->power.button && brick->power.led_off) { loff_t capacity; mars_power_led_off((void*)brick, false); brick->say_channel = get_binding(current); status = -ENOMEM; q = blk_alloc_queue(GFP_MARS); if (!q) { MARS_ERR("cannot allocate device request queue\n"); goto is_down; } q->queuedata = input; input->q = q; disk = alloc_disk(1); if (!disk) { MARS_ERR("cannot allocate gendisk\n"); goto is_down; } minor = device_minor++; //TODO: protect against races (e.g. atomic_t) set_disk_ro(disk, true); disk->queue = q; disk->major = MARS_MAJOR; //TODO: make this dynamic for >256 devices disk->first_minor = minor; disk->fops = &if_blkdev_ops; snprintf(disk->disk_name, sizeof(disk->disk_name), "mars/%s", brick->brick_name); disk->private_data = input; input->disk = disk; capacity = if_get_capacity(brick); MARS_DBG("created device name %s, capacity=%lld\n", disk->disk_name, capacity); if_set_capacity(input, capacity); blk_queue_make_request(q, if_make_request); #ifdef USE_MAX_SECTORS #ifdef MAX_SEGMENT_SIZE MARS_DBG("blk_queue_max_sectors()\n"); blk_queue_max_sectors(q, USE_MAX_SECTORS); #else MARS_DBG("blk_queue_max_hw_sectors()\n"); blk_queue_max_hw_sectors(q, USE_MAX_SECTORS); #endif #endif #ifdef USE_MAX_PHYS_SEGMENTS #ifdef MAX_SEGMENT_SIZE MARS_DBG("blk_queue_max_phys_segments()\n"); blk_queue_max_phys_segments(q, USE_MAX_PHYS_SEGMENTS); #else MARS_DBG("blk_queue_max_segments()\n"); blk_queue_max_segments(q, USE_MAX_PHYS_SEGMENTS); #endif #endif #ifdef USE_MAX_HW_SEGMENTS MARS_DBG("blk_queue_max_hw_segments()\n"); blk_queue_max_hw_segments(q, USE_MAX_HW_SEGMENTS); #endif #ifdef USE_MAX_SEGMENT_SIZE MARS_DBG("blk_queue_max_segment_size()\n"); blk_queue_max_segment_size(q, USE_MAX_SEGMENT_SIZE); #endif #ifdef USE_LOGICAL_BLOCK_SIZE MARS_DBG("blk_queue_logical_block_size()\n"); blk_queue_logical_block_size(q, USE_LOGICAL_BLOCK_SIZE); #endif #ifdef USE_SEGMENT_BOUNDARY MARS_DBG("blk_queue_segment_boundary()\n"); blk_queue_segment_boundary(q, USE_SEGMENT_BOUNDARY); #endif #ifdef QUEUE_ORDERED_DRAIN MARS_DBG("blk_queue_ordered()\n"); blk_queue_ordered(q, QUEUE_ORDERED_DRAIN, NULL); #endif MARS_DBG("blk_queue_bounce_limit()\n"); blk_queue_bounce_limit(q, BLK_BOUNCE_ANY); #ifndef BLK_MAX_REQUEST_COUNT MARS_DBG("unplug_fn\n"); q->unplug_fn = if_unplug; #endif MARS_DBG("queue_lock\n"); q->queue_lock = &input->req_lock; // needed! input->bdev = bdget(MKDEV(disk->major, minor)); /* we have no partitions. we contain only ourselves. */ input->bdev->bd_contains = input->bdev; #ifdef MODIFY_READAHEAD MARS_INF("ra_pages OLD = %lu NEW = %d\n", q->backing_dev_info.ra_pages, brick->readahead); q->backing_dev_info.ra_pages = brick->readahead; #endif #ifdef USE_CONGESTED_FN MARS_DBG("congested_fn\n"); q->backing_dev_info.congested_fn = mars_congested; q->backing_dev_info.congested_data = input; #endif // remove_this #ifdef HAS_MERGE_BVEC MARS_DBG("blk_queue_merge_bvec()\n"); blk_queue_merge_bvec(q, mars_merge_bvec); #endif // end_remove_this q->nr_requests = if_nr_requests; // point of no return MARS_DBG("add_disk()\n"); add_disk(disk); #if 1 set_disk_ro(disk, false); #else set_device_ro(input->bdev, 0); // TODO: implement modes #endif // report success mars_power_led_on((void*)brick, true); status = 0; } // brick should be switched off if (!brick->power.button && !brick->power.led_off) { int opened; int plugged; int flying; mars_power_led_on((void*)brick, false); disk = input->disk; if (!disk) goto is_down; opened = atomic_read(&brick->open_count); if (unlikely(opened > 0)) { MARS_INF("device '%s' is open %d times, cannot shutdown\n", disk->disk_name, opened); status = -EBUSY; goto done; // don't indicate "off" status } plugged = atomic_read(&input->plugged_count); if (unlikely(plugged > 0)) { MARS_INF("device '%s' has %d plugged requests, cannot shutdown\n", disk->disk_name, plugged); status = -EBUSY; goto done; // don't indicate "off" status } flying = atomic_read(&input->flying_count); if (unlikely(flying > 0)) { MARS_INF("device '%s' has %d flying requests, cannot shutdown\n", disk->disk_name, flying); status = -EBUSY; goto done; // don't indicate "off" status } MARS_DBG("calling del_gendisk()\n"); del_gendisk(input->disk); /* There might be subtle races */ while (atomic_read(&input->flying_count) > 0) { MARS_WRN("device '%s' unexpectedly has %d flying requests\n", disk->disk_name, flying); brick_msleep(1000); } if (input->bdev) { MARS_DBG("calling bdput()\n"); bdput(input->bdev); input->bdev = NULL; } MARS_DBG("calling put_disk()\n"); put_disk(input->disk); input->disk = NULL; q = input->q; if (q) { blk_cleanup_queue(q); input->q = NULL; } status = 0; is_down: mars_power_led_off((void*)brick, true); } done: up(&brick->switch_sem); return status; } //////////////// interface to the outer world (kernel) /////////////// static int if_open(struct block_device *bdev, fmode_t mode) { struct if_input *input; struct if_brick *brick; if (unlikely(!bdev || !bdev->bd_disk)) { MARS_ERR("----------------------- INVAL ------------------------------\n"); return -EINVAL; } input = bdev->bd_disk->private_data; if (unlikely(!input || !input->brick)) { MARS_ERR("----------------------- BAD IF SETUP ------------------------------\n"); return -EINVAL; } brick = input->brick; down(&brick->switch_sem); if (unlikely(!brick->power.led_on)) { MARS_INF("----------------------- BUSY %d ------------------------------\n", atomic_read(&brick->open_count)); up(&brick->switch_sem); return -EBUSY; } atomic_inc(&brick->open_count); MARS_INF("----------------------- OPEN %d ------------------------------\n", atomic_read(&brick->open_count)); up(&brick->switch_sem); return 0; } static // remove_this #ifdef HAS_VOID_RELEASE // end_remove_this void // remove_this #else int #endif // end_remove_this if_release(struct gendisk *gd, fmode_t mode) { struct if_input *input = gd->private_data; struct if_brick *brick = input->brick; int nr; MARS_INF("----------------------- CLOSE %d ------------------------------\n", atomic_read(&brick->open_count)); if (atomic_dec_and_test(&brick->open_count)) { while ((nr = atomic_read(&input->flying_count)) > 0) { MARS_INF("%d IO requests not yet completed\n", nr); brick_msleep(1000); } MARS_DBG("status button=%d led_on=%d led_off=%d\n", brick->power.button, brick->power.led_on, brick->power.led_off); mars_trigger(); } // remove_this #ifndef HAS_VOID_RELEASE return 0; #endif // end_remove_this } static const struct block_device_operations if_blkdev_ops = { .owner = THIS_MODULE, .open = if_open, .release = if_release, }; //////////////// informational / statistics /////////////// static char *if_statistics(struct if_brick *brick, int verbose) { struct if_input *input = brick->inputs[0]; char *res = brick_string_alloc(512); int tmp0 = atomic_read(&input->total_reada_count); int tmp1 = atomic_read(&input->total_read_count); int tmp2 = atomic_read(&input->total_mref_read_count); int tmp3 = atomic_read(&input->total_write_count); int tmp4 = atomic_read(&input->total_mref_write_count); if (!res) return NULL; snprintf(res, 512, "total reada = %d " "reads = %d " "mref_reads = %d (%d%%) " "writes = %d " "mref_writes = %d (%d%%) " "empty = %d " "fired = %d " "skip_sync = %d " "| " "plugged = %d " "flying = %d " "(reads = %d writes = %d)\n", tmp0, tmp1, tmp2, tmp1 ? tmp2 * 100 / tmp1 : 0, tmp3, tmp4, tmp3 ? tmp4 * 100 / tmp3 : 0, atomic_read(&input->total_empty_count), atomic_read(&input->total_fire_count), atomic_read(&input->total_skip_sync_count), atomic_read(&input->plugged_count), atomic_read(&input->flying_count), atomic_read(&input->read_flying_count), atomic_read(&input->write_flying_count)); return res; } static void if_reset_statistics(struct if_brick *brick) { struct if_input *input = brick->inputs[0]; atomic_set(&input->total_read_count, 0); atomic_set(&input->total_write_count, 0); atomic_set(&input->total_empty_count, 0); atomic_set(&input->total_fire_count, 0); atomic_set(&input->total_skip_sync_count, 0); atomic_set(&input->total_mref_read_count, 0); atomic_set(&input->total_mref_write_count, 0); } ////////////////// own brick / input / output operations ////////////////// // none //////////////// object / aspect constructors / destructors /////////////// static int if_mref_aspect_init_fn(struct generic_aspect *_ini) { struct if_mref_aspect *ini = (void*)_ini; INIT_LIST_HEAD(&ini->plug_head); INIT_LIST_HEAD(&ini->hash_head); return 0; } static void if_mref_aspect_exit_fn(struct generic_aspect *_ini) { struct if_mref_aspect *ini = (void*)_ini; CHECK_HEAD_EMPTY(&ini->plug_head); CHECK_HEAD_EMPTY(&ini->hash_head); } MARS_MAKE_STATICS(if); //////////////////////// constructors / destructors //////////////////////// static int if_brick_construct(struct if_brick *brick) { sema_init(&brick->switch_sem, 1); atomic_set(&brick->open_count, 0); return 0; } static int if_brick_destruct(struct if_brick *brick) { return 0; } static int if_input_construct(struct if_input *input) { int i; input->hash_table = brick_block_alloc(0, PAGE_SIZE); if (unlikely(!input->hash_table)) { MARS_ERR("cannot allocate hash table\n"); return -ENOMEM; } for (i = 0; i < IF_HASH_MAX; i++) { spin_lock_init(&input->hash_table[i].hash_lock); INIT_LIST_HEAD(&input->hash_table[i].hash_anchor); } INIT_LIST_HEAD(&input->plug_anchor); sema_init(&input->kick_sem, 1); spin_lock_init(&input->req_lock); atomic_set(&input->flying_count, 0); atomic_set(&input->read_flying_count, 0); atomic_set(&input->write_flying_count, 0); atomic_set(&input->plugged_count, 0); #ifdef USE_TIMER init_timer(&input->timer); #endif return 0; } static int if_input_destruct(struct if_input *input) { int i; for (i = 0; i < IF_HASH_MAX; i++) { CHECK_HEAD_EMPTY(&input->hash_table[i].hash_anchor); } CHECK_HEAD_EMPTY(&input->plug_anchor); brick_block_free(input->hash_table, PAGE_SIZE); return 0; } static int if_output_construct(struct if_output *output) { return 0; } ///////////////////////// static structs //////////////////////// static struct if_brick_ops if_brick_ops = { .brick_switch = if_switch, .brick_statistics = if_statistics, .reset_statistics = if_reset_statistics, }; static struct if_output_ops if_output_ops = { }; const struct if_input_type if_input_type = { .type_name = "if_input", .input_size = sizeof(struct if_input), .input_construct = &if_input_construct, .input_destruct = &if_input_destruct, }; static const struct if_input_type *if_input_types[] = { &if_input_type, }; const struct if_output_type if_output_type = { .type_name = "if_output", .output_size = sizeof(struct if_output), .master_ops = &if_output_ops, .output_construct = &if_output_construct, }; static const struct if_output_type *if_output_types[] = { &if_output_type, }; const struct if_brick_type if_brick_type = { .type_name = "if_brick", .brick_size = sizeof(struct if_brick), .max_inputs = 1, .max_outputs = 0, .master_ops = &if_brick_ops, .aspect_types = if_aspect_types, .default_input_types = if_input_types, .default_output_types = if_output_types, .brick_construct = &if_brick_construct, .brick_destruct = &if_brick_destruct, }; EXPORT_SYMBOL_GPL(if_brick_type); ////////////////// module init stuff ///////////////////////// void exit_mars_if(void) { int status; MARS_INF("exit_if()\n"); status = if_unregister_brick_type(); unregister_blkdev(MARS_MAJOR, "mars"); } int __init init_mars_if(void) { int status; (void)if_aspect_types; // not used, shut up gcc MARS_INF("init_if()\n"); status = register_blkdev(MARS_MAJOR, "mars"); if (status) return status; status = if_register_brick_type(); if (status) goto err_device; return status; err_device: MARS_ERR("init_if() status=%d\n", status); exit_mars_if(); return status; }