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![Linus Torvalds](/assets/img/avatar_default.png)
Pull device mapper update from Mike Snitzer: - a couple small cleanups in dm-cache, dm-verity, persistent-data's dm-btree, and DM core. - a 4.1-stable fix for dm-cache that fixes the leaking of deferred bio prison cells - a 4.2-stable fix that adds feature reporting for the dm-stats features added in 4.2 - improve DM-snapshot to not invalidate the on-disk snapshot if snapshot device write overflow occurs; but a write overflow triggered through the origin device will still invalidate the snapshot. - optimize DM-thinp's async discard submission a bit now that late bio splitting has been included in block core. - switch DM-cache's SMQ policy lock from using a mutex to a spinlock; improves performance on very low latency devices (eg. NVMe SSD). - document DM RAID 4/5/6's discard support [ I did not pull the slab changes, which weren't appropriate for this tree, and weren't obviously the right thing to do anyway. At the very least they need some discussion and explanation before getting merged. Because not pulling the actual tagged commit but doing a partial pull instead, this merge commit thus also obviously is missing the git signature from the original tag ] * tag 'dm-4.3-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm: dm cache: fix use after freeing migrations dm cache: small cleanups related to deferred prison cell cleanup dm cache: fix leaking of deferred bio prison cells dm raid: document RAID 4/5/6 discard support dm stats: report precise_timestamps and histogram in @stats_list output dm thin: optimize async discard submission dm snapshot: don't invalidate on-disk image on snapshot write overflow dm: remove unlikely() before IS_ERR() dm: do not override error code returned from dm_get_device() dm: test return value for DM_MAPIO_SUBMITTED dm verity: remove unused mempool dm cache: move wake_waker() from free_migrations() to where it is needed dm btree remove: remove unused function get_nr_entries() dm btree: remove unused "dm_block_t root" parameter in btree_split_sibling() dm cache policy smq: change the mutex to a spinlock
444 lines
9.8 KiB
C
444 lines
9.8 KiB
C
/*
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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/slab.h>
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#include <linux/log2.h>
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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[0];
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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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static inline struct stripe_c *alloc_context(unsigned int stripes)
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{
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size_t len;
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if (dm_array_too_big(sizeof(struct stripe_c), sizeof(struct stripe),
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stripes))
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return NULL;
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len = sizeof(struct stripe_c) + (sizeof(struct stripe) * stripes);
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return kmalloc(len, GFP_KERNEL);
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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 "
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"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 "
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"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 "
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"specified";
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return -EINVAL;
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}
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sc = alloc_context(stripes);
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if (!sc) {
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ti->error = "Memory allocation for striped context "
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"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_write_same_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 = (struct stripe_c *) 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->bi_bdev = 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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} else {
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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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}
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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 target_bio_nr;
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if (bio->bi_rw & REQ_FLUSH) {
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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->bi_bdev = 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->bi_rw & REQ_DISCARD) ||
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unlikely(bio->bi_rw & REQ_WRITE_SAME)) {
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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->bi_bdev = sc->stripe[stripe].dev->bdev;
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return DM_MAPIO_REMAPPED;
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}
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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 status_flags, char *result, unsigned maxlen)
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{
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struct stripe_c *sc = (struct stripe_c *) ti->private;
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char buffer[sc->stripes + 1];
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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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buffer[i] = atomic_read(&(sc->stripe[i].error_count)) ?
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'D' : 'A';
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}
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buffer[i] = '\0';
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DMEMIT("1 %s", buffer);
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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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}
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}
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static int stripe_end_io(struct dm_target *ti, struct bio *bio, int error)
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{
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unsigned 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 0; /* I/O complete */
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if ((error == -EWOULDBLOCK) && (bio->bi_rw & REQ_RAHEAD))
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return error;
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if (error == -EOPNOTSUPP)
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return error;
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memset(major_minor, 0, sizeof(major_minor));
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sprintf(major_minor, "%d:%d",
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MAJOR(disk_devt(bio->bi_bdev->bd_disk)),
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MINOR(disk_devt(bio->bi_bdev->bd_disk)));
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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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schedule_work(&sc->trigger_event);
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}
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return error;
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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 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 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, 5, 1},
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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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};
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int __init dm_stripe_init(void)
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{
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int r;
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r = dm_register_target(&stripe_target);
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if (r < 0)
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DMWARN("target registration failed");
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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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}
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