308 lines
7.6 KiB
C
308 lines
7.6 KiB
C
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// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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linear.c : Multiple Devices driver for Linux
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Copyright (C) 1994-96 Marc ZYNGIER
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<zyngier@ufr-info-p7.ibp.fr> or
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<maz@gloups.fdn.fr>
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Linear mode management functions.
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*/
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#include <linux/blkdev.h>
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#include <linux/raid/md_u.h>
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#include <linux/seq_file.h>
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#include <linux/module.h>
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#include <linux/slab.h>
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#include <trace/events/block.h>
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#include "md.h"
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#include "md-linear.h"
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/*
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* find which device holds a particular offset
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*/
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static inline struct dev_info *which_dev(struct mddev *mddev, sector_t sector)
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{
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int lo, mid, hi;
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struct linear_conf *conf;
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lo = 0;
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hi = mddev->raid_disks - 1;
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conf = mddev->private;
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/*
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* Binary Search
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*/
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while (hi > lo) {
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mid = (hi + lo) / 2;
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if (sector < conf->disks[mid].end_sector)
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hi = mid;
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else
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lo = mid + 1;
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}
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return conf->disks + lo;
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}
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static sector_t linear_size(struct mddev *mddev, sector_t sectors, int raid_disks)
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{
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struct linear_conf *conf;
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sector_t array_sectors;
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conf = mddev->private;
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WARN_ONCE(sectors || raid_disks,
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"%s does not support generic reshape\n", __func__);
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array_sectors = conf->array_sectors;
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return array_sectors;
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}
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static struct linear_conf *linear_conf(struct mddev *mddev, int raid_disks)
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{
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struct linear_conf *conf;
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struct md_rdev *rdev;
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int i, cnt;
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conf = kzalloc(struct_size(conf, disks, raid_disks), GFP_KERNEL);
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if (!conf)
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return NULL;
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cnt = 0;
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conf->array_sectors = 0;
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rdev_for_each(rdev, mddev) {
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int j = rdev->raid_disk;
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struct dev_info *disk = conf->disks + j;
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sector_t sectors;
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if (j < 0 || j >= raid_disks || disk->rdev) {
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pr_warn("md/linear:%s: disk numbering problem. Aborting!\n",
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mdname(mddev));
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goto out;
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}
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disk->rdev = rdev;
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if (mddev->chunk_sectors) {
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sectors = rdev->sectors;
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sector_div(sectors, mddev->chunk_sectors);
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rdev->sectors = sectors * mddev->chunk_sectors;
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}
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disk_stack_limits(mddev->gendisk, rdev->bdev,
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rdev->data_offset << 9);
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conf->array_sectors += rdev->sectors;
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cnt++;
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}
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if (cnt != raid_disks) {
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pr_warn("md/linear:%s: not enough drives present. Aborting!\n",
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mdname(mddev));
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goto out;
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}
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/*
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* Here we calculate the device offsets.
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*/
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conf->disks[0].end_sector = conf->disks[0].rdev->sectors;
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for (i = 1; i < raid_disks; i++)
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conf->disks[i].end_sector =
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conf->disks[i-1].end_sector +
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conf->disks[i].rdev->sectors;
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/*
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* conf->raid_disks is copy of mddev->raid_disks. The reason to
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* keep a copy of mddev->raid_disks in struct linear_conf is,
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* mddev->raid_disks may not be consistent with pointers number of
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* conf->disks[] when it is updated in linear_add() and used to
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* iterate old conf->disks[] earray in linear_congested().
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* Here conf->raid_disks is always consitent with number of
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* pointers in conf->disks[] array, and mddev->private is updated
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* with rcu_assign_pointer() in linear_addr(), such race can be
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* avoided.
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*/
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conf->raid_disks = raid_disks;
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return conf;
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out:
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kfree(conf);
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return NULL;
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}
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static int linear_run (struct mddev *mddev)
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{
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struct linear_conf *conf;
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int ret;
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if (md_check_no_bitmap(mddev))
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return -EINVAL;
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conf = linear_conf(mddev, mddev->raid_disks);
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if (!conf)
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return 1;
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mddev->private = conf;
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md_set_array_sectors(mddev, linear_size(mddev, 0, 0));
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ret = md_integrity_register(mddev);
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if (ret) {
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kfree(conf);
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mddev->private = NULL;
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}
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return ret;
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}
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static int linear_add(struct mddev *mddev, struct md_rdev *rdev)
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{
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/* Adding a drive to a linear array allows the array to grow.
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* It is permitted if the new drive has a matching superblock
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* already on it, with raid_disk equal to raid_disks.
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* It is achieved by creating a new linear_private_data structure
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* and swapping it in in-place of the current one.
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* The current one is never freed until the array is stopped.
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* This avoids races.
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*/
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struct linear_conf *newconf, *oldconf;
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if (rdev->saved_raid_disk != mddev->raid_disks)
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return -EINVAL;
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rdev->raid_disk = rdev->saved_raid_disk;
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rdev->saved_raid_disk = -1;
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newconf = linear_conf(mddev,mddev->raid_disks+1);
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if (!newconf)
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return -ENOMEM;
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/* newconf->raid_disks already keeps a copy of * the increased
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* value of mddev->raid_disks, WARN_ONCE() is just used to make
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* sure of this. It is possible that oldconf is still referenced
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* in linear_congested(), therefore kfree_rcu() is used to free
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* oldconf until no one uses it anymore.
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*/
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mddev_suspend(mddev);
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oldconf = rcu_dereference_protected(mddev->private,
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lockdep_is_held(&mddev->reconfig_mutex));
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mddev->raid_disks++;
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WARN_ONCE(mddev->raid_disks != newconf->raid_disks,
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"copied raid_disks doesn't match mddev->raid_disks");
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rcu_assign_pointer(mddev->private, newconf);
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md_set_array_sectors(mddev, linear_size(mddev, 0, 0));
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set_capacity_and_notify(mddev->gendisk, mddev->array_sectors);
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mddev_resume(mddev);
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kfree_rcu(oldconf, rcu);
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return 0;
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}
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static void linear_free(struct mddev *mddev, void *priv)
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{
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struct linear_conf *conf = priv;
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kfree(conf);
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}
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static bool linear_make_request(struct mddev *mddev, struct bio *bio)
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{
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struct dev_info *tmp_dev;
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sector_t start_sector, end_sector, data_offset;
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sector_t bio_sector = bio->bi_iter.bi_sector;
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if (unlikely(bio->bi_opf & REQ_PREFLUSH)
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&& md_flush_request(mddev, bio))
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return true;
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tmp_dev = which_dev(mddev, bio_sector);
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start_sector = tmp_dev->end_sector - tmp_dev->rdev->sectors;
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end_sector = tmp_dev->end_sector;
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data_offset = tmp_dev->rdev->data_offset;
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if (unlikely(bio_sector >= end_sector ||
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bio_sector < start_sector))
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goto out_of_bounds;
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if (unlikely(is_mddev_broken(tmp_dev->rdev, "linear"))) {
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bio_io_error(bio);
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return true;
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}
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if (unlikely(bio_end_sector(bio) > end_sector)) {
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/* This bio crosses a device boundary, so we have to split it */
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struct bio *split = bio_split(bio, end_sector - bio_sector,
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GFP_NOIO, &mddev->bio_set);
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bio_chain(split, bio);
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submit_bio_noacct(bio);
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bio = split;
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}
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bio_set_dev(bio, tmp_dev->rdev->bdev);
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bio->bi_iter.bi_sector = bio->bi_iter.bi_sector -
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start_sector + data_offset;
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if (unlikely((bio_op(bio) == REQ_OP_DISCARD) &&
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!bdev_max_discard_sectors(bio->bi_bdev))) {
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/* Just ignore it */
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bio_endio(bio);
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} else {
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if (mddev->gendisk)
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trace_block_bio_remap(bio, disk_devt(mddev->gendisk),
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bio_sector);
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mddev_check_write_zeroes(mddev, bio);
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submit_bio_noacct(bio);
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}
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return true;
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out_of_bounds:
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pr_err("md/linear:%s: make_request: Sector %llu out of bounds on dev %pg: %llu sectors, offset %llu\n",
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mdname(mddev),
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(unsigned long long)bio->bi_iter.bi_sector,
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tmp_dev->rdev->bdev,
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(unsigned long long)tmp_dev->rdev->sectors,
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(unsigned long long)start_sector);
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bio_io_error(bio);
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return true;
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}
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static void linear_status (struct seq_file *seq, struct mddev *mddev)
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{
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seq_printf(seq, " %dk rounding", mddev->chunk_sectors / 2);
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}
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static void linear_quiesce(struct mddev *mddev, int state)
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{
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}
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static struct md_personality linear_personality =
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{
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.name = "linear",
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.level = LEVEL_LINEAR,
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.owner = THIS_MODULE,
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.make_request = linear_make_request,
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.run = linear_run,
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.free = linear_free,
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.status = linear_status,
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.hot_add_disk = linear_add,
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.size = linear_size,
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.quiesce = linear_quiesce,
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};
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static int __init linear_init (void)
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{
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return register_md_personality (&linear_personality);
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}
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static void linear_exit (void)
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{
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unregister_md_personality (&linear_personality);
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}
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module_init(linear_init);
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module_exit(linear_exit);
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MODULE_LICENSE("GPL");
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MODULE_DESCRIPTION("Linear device concatenation personality for MD (deprecated)");
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MODULE_ALIAS("md-personality-1"); /* LINEAR - deprecated*/
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MODULE_ALIAS("md-linear");
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MODULE_ALIAS("md-level--1");
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