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![Bryan Gurney](/assets/img/avatar_default.png)
In the dust_map_write() function, change the return code variable "ret" to "r", to match the convention of the other device-mapper targets. Signed-off-by: Bryan Gurney <bgurney@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
559 lines
13 KiB
C
559 lines
13 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright (c) 2018 Red Hat, Inc.
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*
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* This is a test "dust" device, which fails reads on specified
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* sectors, emulating the behavior of a hard disk drive sending
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* a "Read Medium Error" sense.
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*
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*/
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#include <linux/device-mapper.h>
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#include <linux/module.h>
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#include <linux/rbtree.h>
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#define DM_MSG_PREFIX "dust"
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struct badblock {
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struct rb_node node;
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sector_t bb;
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unsigned char wr_fail_cnt;
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};
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struct dust_device {
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struct dm_dev *dev;
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struct rb_root badblocklist;
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unsigned long long badblock_count;
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spinlock_t dust_lock;
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unsigned int blksz;
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int sect_per_block_shift;
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unsigned int sect_per_block;
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sector_t start;
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bool fail_read_on_bb:1;
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bool quiet_mode:1;
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};
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static struct badblock *dust_rb_search(struct rb_root *root, sector_t blk)
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{
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struct rb_node *node = root->rb_node;
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while (node) {
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struct badblock *bblk = rb_entry(node, struct badblock, node);
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if (bblk->bb > blk)
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node = node->rb_left;
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else if (bblk->bb < blk)
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node = node->rb_right;
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else
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return bblk;
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}
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return NULL;
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}
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static bool dust_rb_insert(struct rb_root *root, struct badblock *new)
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{
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struct badblock *bblk;
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struct rb_node **link = &root->rb_node, *parent = NULL;
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sector_t value = new->bb;
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while (*link) {
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parent = *link;
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bblk = rb_entry(parent, struct badblock, node);
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if (bblk->bb > value)
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link = &(*link)->rb_left;
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else if (bblk->bb < value)
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link = &(*link)->rb_right;
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else
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return false;
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}
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rb_link_node(&new->node, parent, link);
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rb_insert_color(&new->node, root);
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return true;
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}
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static int dust_remove_block(struct dust_device *dd, unsigned long long block)
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{
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struct badblock *bblock;
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unsigned long flags;
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spin_lock_irqsave(&dd->dust_lock, flags);
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bblock = dust_rb_search(&dd->badblocklist, block);
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if (bblock == NULL) {
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if (!dd->quiet_mode) {
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DMERR("%s: block %llu not found in badblocklist",
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__func__, block);
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}
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spin_unlock_irqrestore(&dd->dust_lock, flags);
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return -EINVAL;
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}
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rb_erase(&bblock->node, &dd->badblocklist);
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dd->badblock_count--;
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if (!dd->quiet_mode)
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DMINFO("%s: badblock removed at block %llu", __func__, block);
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kfree(bblock);
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spin_unlock_irqrestore(&dd->dust_lock, flags);
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return 0;
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}
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static int dust_add_block(struct dust_device *dd, unsigned long long block,
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unsigned char wr_fail_cnt)
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{
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struct badblock *bblock;
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unsigned long flags;
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bblock = kmalloc(sizeof(*bblock), GFP_KERNEL);
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if (bblock == NULL) {
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if (!dd->quiet_mode)
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DMERR("%s: badblock allocation failed", __func__);
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return -ENOMEM;
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}
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spin_lock_irqsave(&dd->dust_lock, flags);
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bblock->bb = block;
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bblock->wr_fail_cnt = wr_fail_cnt;
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if (!dust_rb_insert(&dd->badblocklist, bblock)) {
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if (!dd->quiet_mode) {
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DMERR("%s: block %llu already in badblocklist",
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__func__, block);
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}
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spin_unlock_irqrestore(&dd->dust_lock, flags);
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kfree(bblock);
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return -EINVAL;
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}
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dd->badblock_count++;
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if (!dd->quiet_mode) {
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DMINFO("%s: badblock added at block %llu with write fail count %hhu",
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__func__, block, wr_fail_cnt);
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}
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spin_unlock_irqrestore(&dd->dust_lock, flags);
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return 0;
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}
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static int dust_query_block(struct dust_device *dd, unsigned long long block)
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{
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struct badblock *bblock;
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unsigned long flags;
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spin_lock_irqsave(&dd->dust_lock, flags);
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bblock = dust_rb_search(&dd->badblocklist, block);
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if (bblock != NULL)
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DMINFO("%s: block %llu found in badblocklist", __func__, block);
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else
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DMINFO("%s: block %llu not found in badblocklist", __func__, block);
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spin_unlock_irqrestore(&dd->dust_lock, flags);
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return 0;
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}
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static int __dust_map_read(struct dust_device *dd, sector_t thisblock)
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{
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struct badblock *bblk = dust_rb_search(&dd->badblocklist, thisblock);
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if (bblk)
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return DM_MAPIO_KILL;
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return DM_MAPIO_REMAPPED;
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}
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static int dust_map_read(struct dust_device *dd, sector_t thisblock,
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bool fail_read_on_bb)
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{
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unsigned long flags;
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int r = DM_MAPIO_REMAPPED;
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if (fail_read_on_bb) {
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thisblock >>= dd->sect_per_block_shift;
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spin_lock_irqsave(&dd->dust_lock, flags);
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r = __dust_map_read(dd, thisblock);
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spin_unlock_irqrestore(&dd->dust_lock, flags);
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}
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return r;
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}
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static int __dust_map_write(struct dust_device *dd, sector_t thisblock)
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{
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struct badblock *bblk = dust_rb_search(&dd->badblocklist, thisblock);
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if (bblk && bblk->wr_fail_cnt > 0) {
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bblk->wr_fail_cnt--;
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return DM_MAPIO_KILL;
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}
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if (bblk) {
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rb_erase(&bblk->node, &dd->badblocklist);
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dd->badblock_count--;
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kfree(bblk);
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if (!dd->quiet_mode) {
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sector_div(thisblock, dd->sect_per_block);
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DMINFO("block %llu removed from badblocklist by write",
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(unsigned long long)thisblock);
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}
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}
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return DM_MAPIO_REMAPPED;
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}
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static int dust_map_write(struct dust_device *dd, sector_t thisblock,
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bool fail_read_on_bb)
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{
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unsigned long flags;
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int r = DM_MAPIO_REMAPPED;
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if (fail_read_on_bb) {
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thisblock >>= dd->sect_per_block_shift;
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spin_lock_irqsave(&dd->dust_lock, flags);
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r = __dust_map_write(dd, thisblock);
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spin_unlock_irqrestore(&dd->dust_lock, flags);
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}
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return r;
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}
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static int dust_map(struct dm_target *ti, struct bio *bio)
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{
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struct dust_device *dd = ti->private;
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int r;
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bio_set_dev(bio, dd->dev->bdev);
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bio->bi_iter.bi_sector = dd->start + dm_target_offset(ti, bio->bi_iter.bi_sector);
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if (bio_data_dir(bio) == READ)
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r = dust_map_read(dd, bio->bi_iter.bi_sector, dd->fail_read_on_bb);
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else
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r = dust_map_write(dd, bio->bi_iter.bi_sector, dd->fail_read_on_bb);
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return r;
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}
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static bool __dust_clear_badblocks(struct rb_root *tree,
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unsigned long long count)
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{
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struct rb_node *node = NULL, *nnode = NULL;
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nnode = rb_first(tree);
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if (nnode == NULL) {
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BUG_ON(count != 0);
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return false;
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}
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while (nnode) {
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node = nnode;
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nnode = rb_next(node);
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rb_erase(node, tree);
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count--;
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kfree(node);
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}
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BUG_ON(count != 0);
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BUG_ON(tree->rb_node != NULL);
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return true;
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}
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static int dust_clear_badblocks(struct dust_device *dd)
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{
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unsigned long flags;
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struct rb_root badblocklist;
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unsigned long long badblock_count;
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spin_lock_irqsave(&dd->dust_lock, flags);
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badblocklist = dd->badblocklist;
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badblock_count = dd->badblock_count;
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dd->badblocklist = RB_ROOT;
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dd->badblock_count = 0;
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spin_unlock_irqrestore(&dd->dust_lock, flags);
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if (!__dust_clear_badblocks(&badblocklist, badblock_count))
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DMINFO("%s: no badblocks found", __func__);
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else
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DMINFO("%s: badblocks cleared", __func__);
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return 0;
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}
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/*
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* Target parameters:
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*
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* <device_path> <offset> <blksz>
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*
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* device_path: path to the block device
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* offset: offset to data area from start of device_path
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* blksz: block size (minimum 512, maximum 1073741824, must be a power of 2)
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*/
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static int dust_ctr(struct dm_target *ti, unsigned int argc, char **argv)
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{
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struct dust_device *dd;
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unsigned long long tmp;
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char dummy;
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unsigned int blksz;
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unsigned int sect_per_block;
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sector_t DUST_MAX_BLKSZ_SECTORS = 2097152;
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sector_t max_block_sectors = min(ti->len, DUST_MAX_BLKSZ_SECTORS);
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if (argc != 3) {
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ti->error = "Invalid argument count";
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return -EINVAL;
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}
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if (kstrtouint(argv[2], 10, &blksz) || !blksz) {
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ti->error = "Invalid block size parameter";
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return -EINVAL;
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}
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if (blksz < 512) {
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ti->error = "Block size must be at least 512";
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return -EINVAL;
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}
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if (!is_power_of_2(blksz)) {
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ti->error = "Block size must be a power of 2";
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return -EINVAL;
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}
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if (to_sector(blksz) > max_block_sectors) {
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ti->error = "Block size is too large";
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return -EINVAL;
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}
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sect_per_block = (blksz >> SECTOR_SHIFT);
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if (sscanf(argv[1], "%llu%c", &tmp, &dummy) != 1 || tmp != (sector_t)tmp) {
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ti->error = "Invalid device offset sector";
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return -EINVAL;
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}
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dd = kzalloc(sizeof(struct dust_device), GFP_KERNEL);
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if (dd == NULL) {
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ti->error = "Cannot allocate context";
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return -ENOMEM;
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}
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if (dm_get_device(ti, argv[0], dm_table_get_mode(ti->table), &dd->dev)) {
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ti->error = "Device lookup failed";
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kfree(dd);
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return -EINVAL;
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}
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dd->sect_per_block = sect_per_block;
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dd->blksz = blksz;
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dd->start = tmp;
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dd->sect_per_block_shift = __ffs(sect_per_block);
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/*
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* Whether to fail a read on a "bad" block.
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* Defaults to false; enabled later by message.
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*/
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dd->fail_read_on_bb = false;
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/*
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* Initialize bad block list rbtree.
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*/
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dd->badblocklist = RB_ROOT;
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dd->badblock_count = 0;
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spin_lock_init(&dd->dust_lock);
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dd->quiet_mode = false;
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BUG_ON(dm_set_target_max_io_len(ti, dd->sect_per_block) != 0);
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ti->num_discard_bios = 1;
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ti->num_flush_bios = 1;
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ti->private = dd;
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return 0;
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}
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static void dust_dtr(struct dm_target *ti)
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{
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struct dust_device *dd = ti->private;
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__dust_clear_badblocks(&dd->badblocklist, dd->badblock_count);
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dm_put_device(ti, dd->dev);
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kfree(dd);
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}
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static int dust_message(struct dm_target *ti, unsigned int argc, char **argv,
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char *result_buf, unsigned int maxlen)
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{
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struct dust_device *dd = ti->private;
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sector_t size = i_size_read(dd->dev->bdev->bd_inode) >> SECTOR_SHIFT;
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bool invalid_msg = false;
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int r = -EINVAL;
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unsigned long long tmp, block;
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unsigned char wr_fail_cnt;
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unsigned int tmp_ui;
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unsigned long flags;
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char dummy;
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if (argc == 1) {
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if (!strcasecmp(argv[0], "addbadblock") ||
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!strcasecmp(argv[0], "removebadblock") ||
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!strcasecmp(argv[0], "queryblock")) {
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DMERR("%s requires an additional argument", argv[0]);
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} else if (!strcasecmp(argv[0], "disable")) {
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DMINFO("disabling read failures on bad sectors");
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dd->fail_read_on_bb = false;
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r = 0;
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} else if (!strcasecmp(argv[0], "enable")) {
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DMINFO("enabling read failures on bad sectors");
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dd->fail_read_on_bb = true;
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r = 0;
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} else if (!strcasecmp(argv[0], "countbadblocks")) {
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spin_lock_irqsave(&dd->dust_lock, flags);
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DMINFO("countbadblocks: %llu badblock(s) found",
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dd->badblock_count);
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spin_unlock_irqrestore(&dd->dust_lock, flags);
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r = 0;
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} else if (!strcasecmp(argv[0], "clearbadblocks")) {
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r = dust_clear_badblocks(dd);
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} else if (!strcasecmp(argv[0], "quiet")) {
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if (!dd->quiet_mode)
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dd->quiet_mode = true;
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else
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dd->quiet_mode = false;
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r = 0;
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} else {
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invalid_msg = true;
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}
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} else if (argc == 2) {
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if (sscanf(argv[1], "%llu%c", &tmp, &dummy) != 1)
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return r;
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block = tmp;
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sector_div(size, dd->sect_per_block);
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if (block > size) {
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DMERR("selected block value out of range");
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return r;
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}
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if (!strcasecmp(argv[0], "addbadblock"))
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r = dust_add_block(dd, block, 0);
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else if (!strcasecmp(argv[0], "removebadblock"))
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r = dust_remove_block(dd, block);
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else if (!strcasecmp(argv[0], "queryblock"))
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r = dust_query_block(dd, block);
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else
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invalid_msg = true;
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} else if (argc == 3) {
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if (sscanf(argv[1], "%llu%c", &tmp, &dummy) != 1)
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return r;
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if (sscanf(argv[2], "%u%c", &tmp_ui, &dummy) != 1)
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return r;
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block = tmp;
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if (tmp_ui > 255) {
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DMERR("selected write fail count out of range");
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return r;
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}
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wr_fail_cnt = tmp_ui;
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sector_div(size, dd->sect_per_block);
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if (block > size) {
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DMERR("selected block value out of range");
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return r;
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}
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if (!strcasecmp(argv[0], "addbadblock"))
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r = dust_add_block(dd, block, wr_fail_cnt);
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else
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invalid_msg = true;
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} else
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DMERR("invalid number of arguments '%d'", argc);
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if (invalid_msg)
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DMERR("unrecognized message '%s' received", argv[0]);
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return r;
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}
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static void dust_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 dust_device *dd = ti->private;
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unsigned int sz = 0;
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switch (type) {
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case STATUSTYPE_INFO:
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DMEMIT("%s %s %s", dd->dev->name,
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dd->fail_read_on_bb ? "fail_read_on_bad_block" : "bypass",
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dd->quiet_mode ? "quiet" : "verbose");
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break;
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case STATUSTYPE_TABLE:
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DMEMIT("%s %llu %u", dd->dev->name,
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(unsigned long long)dd->start, dd->blksz);
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break;
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}
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}
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static int dust_prepare_ioctl(struct dm_target *ti, struct block_device **bdev)
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{
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struct dust_device *dd = ti->private;
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struct dm_dev *dev = dd->dev;
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*bdev = dev->bdev;
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/*
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* Only pass ioctls through if the device sizes match exactly.
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*/
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if (dd->start ||
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ti->len != i_size_read(dev->bdev->bd_inode) >> SECTOR_SHIFT)
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return 1;
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return 0;
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}
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static int dust_iterate_devices(struct dm_target *ti, iterate_devices_callout_fn fn,
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void *data)
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{
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struct dust_device *dd = ti->private;
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return fn(ti, dd->dev, dd->start, ti->len, data);
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}
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static struct target_type dust_target = {
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.name = "dust",
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.version = {1, 0, 0},
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.module = THIS_MODULE,
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.ctr = dust_ctr,
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.dtr = dust_dtr,
|
|
.iterate_devices = dust_iterate_devices,
|
|
.map = dust_map,
|
|
.message = dust_message,
|
|
.status = dust_status,
|
|
.prepare_ioctl = dust_prepare_ioctl,
|
|
};
|
|
|
|
static int __init dm_dust_init(void)
|
|
{
|
|
int r = dm_register_target(&dust_target);
|
|
|
|
if (r < 0)
|
|
DMERR("dm_register_target failed %d", r);
|
|
|
|
return r;
|
|
}
|
|
|
|
static void __exit dm_dust_exit(void)
|
|
{
|
|
dm_unregister_target(&dust_target);
|
|
}
|
|
|
|
module_init(dm_dust_init);
|
|
module_exit(dm_dust_exit);
|
|
|
|
MODULE_DESCRIPTION(DM_NAME " dust test target");
|
|
MODULE_AUTHOR("Bryan Gurney <dm-devel@redhat.com>");
|
|
MODULE_LICENSE("GPL");
|