503 lines
12 KiB
C
503 lines
12 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Copyright (C) 2001-2003 Sistina Software (UK) Limited.
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*
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* This file is released under the GPL.
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*/
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#include "dm.h"
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#include <linux/device-mapper.h>
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/blkdev.h>
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#include <linux/bio.h>
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#include <linux/dax.h>
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#include <linux/slab.h>
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#include <linux/log2.h>
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static struct workqueue_struct *dm_stripe_wq;
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#define DM_MSG_PREFIX "striped"
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#define DM_IO_ERROR_THRESHOLD 15
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struct stripe {
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struct dm_dev *dev;
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sector_t physical_start;
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atomic_t error_count;
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};
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struct stripe_c {
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uint32_t stripes;
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int stripes_shift;
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/* The size of this target / num. stripes */
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sector_t stripe_width;
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uint32_t chunk_size;
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int chunk_size_shift;
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/* Needed for handling events */
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struct dm_target *ti;
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/* Work struct used for triggering events*/
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struct work_struct trigger_event;
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struct stripe stripe[];
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};
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/*
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* An event is triggered whenever a drive
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* drops out of a stripe volume.
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*/
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static void trigger_event(struct work_struct *work)
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{
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struct stripe_c *sc = container_of(work, struct stripe_c,
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trigger_event);
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dm_table_event(sc->ti->table);
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}
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/*
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* Parse a single <dev> <sector> pair
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*/
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static int get_stripe(struct dm_target *ti, struct stripe_c *sc,
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unsigned int stripe, char **argv)
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{
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unsigned long long start;
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char dummy;
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int ret;
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if (sscanf(argv[1], "%llu%c", &start, &dummy) != 1)
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return -EINVAL;
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ret = dm_get_device(ti, argv[0], dm_table_get_mode(ti->table),
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&sc->stripe[stripe].dev);
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if (ret)
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return ret;
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sc->stripe[stripe].physical_start = start;
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return 0;
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}
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/*
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* Construct a striped mapping.
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* <number of stripes> <chunk size> [<dev_path> <offset>]+
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*/
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static int stripe_ctr(struct dm_target *ti, unsigned int argc, char **argv)
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{
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struct stripe_c *sc;
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sector_t width, tmp_len;
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uint32_t stripes;
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uint32_t chunk_size;
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int r;
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unsigned int i;
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if (argc < 2) {
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ti->error = "Not enough arguments";
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return -EINVAL;
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}
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if (kstrtouint(argv[0], 10, &stripes) || !stripes) {
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ti->error = "Invalid stripe count";
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return -EINVAL;
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}
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if (kstrtouint(argv[1], 10, &chunk_size) || !chunk_size) {
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ti->error = "Invalid chunk_size";
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return -EINVAL;
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}
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width = ti->len;
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if (sector_div(width, stripes)) {
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ti->error = "Target length not divisible by number of stripes";
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return -EINVAL;
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}
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tmp_len = width;
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if (sector_div(tmp_len, chunk_size)) {
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ti->error = "Target length not divisible by chunk size";
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return -EINVAL;
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}
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/*
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* Do we have enough arguments for that many stripes ?
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*/
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if (argc != (2 + 2 * stripes)) {
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ti->error = "Not enough destinations specified";
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return -EINVAL;
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}
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sc = kmalloc(struct_size(sc, stripe, stripes), GFP_KERNEL);
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if (!sc) {
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ti->error = "Memory allocation for striped context failed";
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return -ENOMEM;
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}
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INIT_WORK(&sc->trigger_event, trigger_event);
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/* Set pointer to dm target; used in trigger_event */
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sc->ti = ti;
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sc->stripes = stripes;
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sc->stripe_width = width;
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if (stripes & (stripes - 1))
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sc->stripes_shift = -1;
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else
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sc->stripes_shift = __ffs(stripes);
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r = dm_set_target_max_io_len(ti, chunk_size);
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if (r) {
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kfree(sc);
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return r;
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}
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ti->num_flush_bios = stripes;
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ti->num_discard_bios = stripes;
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ti->num_secure_erase_bios = stripes;
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ti->num_write_zeroes_bios = stripes;
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sc->chunk_size = chunk_size;
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if (chunk_size & (chunk_size - 1))
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sc->chunk_size_shift = -1;
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else
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sc->chunk_size_shift = __ffs(chunk_size);
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/*
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* Get the stripe destinations.
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*/
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for (i = 0; i < stripes; i++) {
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argv += 2;
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r = get_stripe(ti, sc, i, argv);
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if (r < 0) {
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ti->error = "Couldn't parse stripe destination";
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while (i--)
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dm_put_device(ti, sc->stripe[i].dev);
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kfree(sc);
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return r;
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}
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atomic_set(&(sc->stripe[i].error_count), 0);
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}
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ti->private = sc;
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return 0;
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}
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static void stripe_dtr(struct dm_target *ti)
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{
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unsigned int i;
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struct stripe_c *sc = ti->private;
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for (i = 0; i < sc->stripes; i++)
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dm_put_device(ti, sc->stripe[i].dev);
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flush_work(&sc->trigger_event);
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kfree(sc);
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}
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static void stripe_map_sector(struct stripe_c *sc, sector_t sector,
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uint32_t *stripe, sector_t *result)
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{
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sector_t chunk = dm_target_offset(sc->ti, sector);
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sector_t chunk_offset;
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if (sc->chunk_size_shift < 0)
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chunk_offset = sector_div(chunk, sc->chunk_size);
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else {
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chunk_offset = chunk & (sc->chunk_size - 1);
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chunk >>= sc->chunk_size_shift;
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}
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if (sc->stripes_shift < 0)
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*stripe = sector_div(chunk, sc->stripes);
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else {
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*stripe = chunk & (sc->stripes - 1);
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chunk >>= sc->stripes_shift;
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}
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if (sc->chunk_size_shift < 0)
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chunk *= sc->chunk_size;
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else
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chunk <<= sc->chunk_size_shift;
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*result = chunk + chunk_offset;
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}
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static void stripe_map_range_sector(struct stripe_c *sc, sector_t sector,
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uint32_t target_stripe, sector_t *result)
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{
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uint32_t stripe;
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stripe_map_sector(sc, sector, &stripe, result);
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if (stripe == target_stripe)
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return;
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/* round down */
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sector = *result;
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if (sc->chunk_size_shift < 0)
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*result -= sector_div(sector, sc->chunk_size);
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else
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*result = sector & ~(sector_t)(sc->chunk_size - 1);
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if (target_stripe < stripe)
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*result += sc->chunk_size; /* next chunk */
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}
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static int stripe_map_range(struct stripe_c *sc, struct bio *bio,
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uint32_t target_stripe)
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{
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sector_t begin, end;
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stripe_map_range_sector(sc, bio->bi_iter.bi_sector,
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target_stripe, &begin);
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stripe_map_range_sector(sc, bio_end_sector(bio),
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target_stripe, &end);
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if (begin < end) {
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bio_set_dev(bio, sc->stripe[target_stripe].dev->bdev);
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bio->bi_iter.bi_sector = begin +
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sc->stripe[target_stripe].physical_start;
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bio->bi_iter.bi_size = to_bytes(end - begin);
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return DM_MAPIO_REMAPPED;
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}
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/* The range doesn't map to the target stripe */
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bio_endio(bio);
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return DM_MAPIO_SUBMITTED;
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}
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static int stripe_map(struct dm_target *ti, struct bio *bio)
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{
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struct stripe_c *sc = ti->private;
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uint32_t stripe;
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unsigned int target_bio_nr;
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if (bio->bi_opf & REQ_PREFLUSH) {
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target_bio_nr = dm_bio_get_target_bio_nr(bio);
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BUG_ON(target_bio_nr >= sc->stripes);
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bio_set_dev(bio, sc->stripe[target_bio_nr].dev->bdev);
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return DM_MAPIO_REMAPPED;
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}
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if (unlikely(bio_op(bio) == REQ_OP_DISCARD) ||
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unlikely(bio_op(bio) == REQ_OP_SECURE_ERASE) ||
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unlikely(bio_op(bio) == REQ_OP_WRITE_ZEROES)) {
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target_bio_nr = dm_bio_get_target_bio_nr(bio);
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BUG_ON(target_bio_nr >= sc->stripes);
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return stripe_map_range(sc, bio, target_bio_nr);
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}
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stripe_map_sector(sc, bio->bi_iter.bi_sector,
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&stripe, &bio->bi_iter.bi_sector);
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bio->bi_iter.bi_sector += sc->stripe[stripe].physical_start;
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bio_set_dev(bio, sc->stripe[stripe].dev->bdev);
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return DM_MAPIO_REMAPPED;
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}
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#if IS_ENABLED(CONFIG_FS_DAX)
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static struct dax_device *stripe_dax_pgoff(struct dm_target *ti, pgoff_t *pgoff)
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{
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struct stripe_c *sc = ti->private;
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struct block_device *bdev;
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sector_t dev_sector;
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uint32_t stripe;
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stripe_map_sector(sc, *pgoff * PAGE_SECTORS, &stripe, &dev_sector);
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dev_sector += sc->stripe[stripe].physical_start;
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bdev = sc->stripe[stripe].dev->bdev;
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*pgoff = (get_start_sect(bdev) + dev_sector) >> PAGE_SECTORS_SHIFT;
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return sc->stripe[stripe].dev->dax_dev;
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}
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static long stripe_dax_direct_access(struct dm_target *ti, pgoff_t pgoff,
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long nr_pages, enum dax_access_mode mode, void **kaddr,
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pfn_t *pfn)
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{
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struct dax_device *dax_dev = stripe_dax_pgoff(ti, &pgoff);
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return dax_direct_access(dax_dev, pgoff, nr_pages, mode, kaddr, pfn);
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}
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static int stripe_dax_zero_page_range(struct dm_target *ti, pgoff_t pgoff,
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size_t nr_pages)
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{
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struct dax_device *dax_dev = stripe_dax_pgoff(ti, &pgoff);
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return dax_zero_page_range(dax_dev, pgoff, nr_pages);
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}
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static size_t stripe_dax_recovery_write(struct dm_target *ti, pgoff_t pgoff,
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void *addr, size_t bytes, struct iov_iter *i)
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{
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struct dax_device *dax_dev = stripe_dax_pgoff(ti, &pgoff);
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return dax_recovery_write(dax_dev, pgoff, addr, bytes, i);
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}
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#else
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#define stripe_dax_direct_access NULL
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#define stripe_dax_zero_page_range NULL
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#define stripe_dax_recovery_write NULL
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#endif
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/*
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* Stripe status:
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*
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* INFO
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* #stripes [stripe_name <stripe_name>] [group word count]
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* [error count 'A|D' <error count 'A|D'>]
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*
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* TABLE
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* #stripes [stripe chunk size]
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* [stripe_name physical_start <stripe_name physical_start>]
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*
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*/
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static void stripe_status(struct dm_target *ti, status_type_t type,
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unsigned int status_flags, char *result, unsigned int maxlen)
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{
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struct stripe_c *sc = ti->private;
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unsigned int sz = 0;
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unsigned int i;
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switch (type) {
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case STATUSTYPE_INFO:
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DMEMIT("%d ", sc->stripes);
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for (i = 0; i < sc->stripes; i++)
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DMEMIT("%s ", sc->stripe[i].dev->name);
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DMEMIT("1 ");
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for (i = 0; i < sc->stripes; i++)
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DMEMIT("%c", atomic_read(&(sc->stripe[i].error_count)) ? 'D' : 'A');
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break;
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case STATUSTYPE_TABLE:
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DMEMIT("%d %llu", sc->stripes,
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(unsigned long long)sc->chunk_size);
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for (i = 0; i < sc->stripes; i++)
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DMEMIT(" %s %llu", sc->stripe[i].dev->name,
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(unsigned long long)sc->stripe[i].physical_start);
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break;
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case STATUSTYPE_IMA:
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DMEMIT_TARGET_NAME_VERSION(ti->type);
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DMEMIT(",stripes=%d,chunk_size=%llu", sc->stripes,
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(unsigned long long)sc->chunk_size);
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for (i = 0; i < sc->stripes; i++) {
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DMEMIT(",stripe_%d_device_name=%s", i, sc->stripe[i].dev->name);
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DMEMIT(",stripe_%d_physical_start=%llu", i,
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(unsigned long long)sc->stripe[i].physical_start);
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DMEMIT(",stripe_%d_status=%c", i,
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atomic_read(&(sc->stripe[i].error_count)) ? 'D' : 'A');
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}
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DMEMIT(";");
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break;
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}
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}
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static int stripe_end_io(struct dm_target *ti, struct bio *bio,
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blk_status_t *error)
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{
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unsigned int i;
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char major_minor[16];
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struct stripe_c *sc = ti->private;
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if (!*error)
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return DM_ENDIO_DONE; /* I/O complete */
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if (bio->bi_opf & REQ_RAHEAD)
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return DM_ENDIO_DONE;
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if (*error == BLK_STS_NOTSUPP)
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return DM_ENDIO_DONE;
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memset(major_minor, 0, sizeof(major_minor));
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sprintf(major_minor, "%d:%d", MAJOR(bio_dev(bio)), MINOR(bio_dev(bio)));
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/*
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* Test to see which stripe drive triggered the event
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* and increment error count for all stripes on that device.
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* If the error count for a given device exceeds the threshold
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* value we will no longer trigger any further events.
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*/
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for (i = 0; i < sc->stripes; i++)
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if (!strcmp(sc->stripe[i].dev->name, major_minor)) {
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atomic_inc(&(sc->stripe[i].error_count));
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if (atomic_read(&(sc->stripe[i].error_count)) <
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DM_IO_ERROR_THRESHOLD)
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queue_work(dm_stripe_wq, &sc->trigger_event);
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}
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return DM_ENDIO_DONE;
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}
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static int stripe_iterate_devices(struct dm_target *ti,
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iterate_devices_callout_fn fn, void *data)
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{
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struct stripe_c *sc = ti->private;
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int ret = 0;
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unsigned int i = 0;
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do {
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ret = fn(ti, sc->stripe[i].dev,
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sc->stripe[i].physical_start,
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sc->stripe_width, data);
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} while (!ret && ++i < sc->stripes);
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return ret;
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}
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static void stripe_io_hints(struct dm_target *ti,
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struct queue_limits *limits)
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{
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struct stripe_c *sc = ti->private;
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unsigned int chunk_size = sc->chunk_size << SECTOR_SHIFT;
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blk_limits_io_min(limits, chunk_size);
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blk_limits_io_opt(limits, chunk_size * sc->stripes);
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}
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static struct target_type stripe_target = {
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.name = "striped",
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.version = {1, 6, 0},
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.features = DM_TARGET_PASSES_INTEGRITY | DM_TARGET_NOWAIT,
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.module = THIS_MODULE,
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.ctr = stripe_ctr,
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.dtr = stripe_dtr,
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.map = stripe_map,
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.end_io = stripe_end_io,
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.status = stripe_status,
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.iterate_devices = stripe_iterate_devices,
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.io_hints = stripe_io_hints,
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.direct_access = stripe_dax_direct_access,
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.dax_zero_page_range = stripe_dax_zero_page_range,
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.dax_recovery_write = stripe_dax_recovery_write,
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};
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int __init dm_stripe_init(void)
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{
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int r;
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dm_stripe_wq = alloc_workqueue("dm_stripe_wq", 0, 0);
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if (!dm_stripe_wq)
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return -ENOMEM;
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r = dm_register_target(&stripe_target);
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if (r < 0) {
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destroy_workqueue(dm_stripe_wq);
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DMWARN("target registration failed");
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}
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return r;
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}
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void dm_stripe_exit(void)
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{
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dm_unregister_target(&stripe_target);
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destroy_workqueue(dm_stripe_wq);
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}
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