| /* |
| * Copyright (C) 2003 Sistina Software (UK) Limited. |
| * Copyright (C) 2004, 2010 Red Hat, Inc. All rights reserved. |
| * |
| * This file is released under the GPL. |
| */ |
| |
| #include <linux/device-mapper.h> |
| |
| #include <linux/module.h> |
| #include <linux/init.h> |
| #include <linux/blkdev.h> |
| #include <linux/bio.h> |
| #include <linux/slab.h> |
| |
| #define DM_MSG_PREFIX "flakey" |
| |
| /* |
| * Flakey: Used for testing only, simulates intermittent, |
| * catastrophic device failure. |
| */ |
| struct flakey_c { |
| struct dm_dev *dev; |
| unsigned long start_time; |
| sector_t start; |
| unsigned up_interval; |
| unsigned down_interval; |
| }; |
| |
| /* |
| * Construct a flakey mapping: <dev_path> <offset> <up interval> <down interval> |
| */ |
| static int flakey_ctr(struct dm_target *ti, unsigned int argc, char **argv) |
| { |
| struct flakey_c *fc; |
| unsigned long long tmp; |
| |
| if (argc != 4) { |
| ti->error = "dm-flakey: Invalid argument count"; |
| return -EINVAL; |
| } |
| |
| fc = kmalloc(sizeof(*fc), GFP_KERNEL); |
| if (!fc) { |
| ti->error = "dm-flakey: Cannot allocate linear context"; |
| return -ENOMEM; |
| } |
| fc->start_time = jiffies; |
| |
| if (sscanf(argv[1], "%llu", &tmp) != 1) { |
| ti->error = "dm-flakey: Invalid device sector"; |
| goto bad; |
| } |
| fc->start = tmp; |
| |
| if (sscanf(argv[2], "%u", &fc->up_interval) != 1) { |
| ti->error = "dm-flakey: Invalid up interval"; |
| goto bad; |
| } |
| |
| if (sscanf(argv[3], "%u", &fc->down_interval) != 1) { |
| ti->error = "dm-flakey: Invalid down interval"; |
| goto bad; |
| } |
| |
| if (!(fc->up_interval + fc->down_interval)) { |
| ti->error = "dm-flakey: Total (up + down) interval is zero"; |
| goto bad; |
| } |
| |
| if (fc->up_interval + fc->down_interval < fc->up_interval) { |
| ti->error = "dm-flakey: Interval overflow"; |
| goto bad; |
| } |
| |
| if (dm_get_device(ti, argv[0], dm_table_get_mode(ti->table), &fc->dev)) { |
| ti->error = "dm-flakey: Device lookup failed"; |
| goto bad; |
| } |
| |
| ti->num_flush_requests = 1; |
| ti->private = fc; |
| return 0; |
| |
| bad: |
| kfree(fc); |
| return -EINVAL; |
| } |
| |
| static void flakey_dtr(struct dm_target *ti) |
| { |
| struct flakey_c *fc = ti->private; |
| |
| dm_put_device(ti, fc->dev); |
| kfree(fc); |
| } |
| |
| static sector_t flakey_map_sector(struct dm_target *ti, sector_t bi_sector) |
| { |
| struct flakey_c *fc = ti->private; |
| |
| return fc->start + (bi_sector - ti->begin); |
| } |
| |
| static void flakey_map_bio(struct dm_target *ti, struct bio *bio) |
| { |
| struct flakey_c *fc = ti->private; |
| |
| bio->bi_bdev = fc->dev->bdev; |
| if (bio_sectors(bio)) |
| bio->bi_sector = flakey_map_sector(ti, bio->bi_sector); |
| } |
| |
| static int flakey_map(struct dm_target *ti, struct bio *bio, |
| union map_info *map_context) |
| { |
| struct flakey_c *fc = ti->private; |
| unsigned elapsed; |
| |
| /* Are we alive ? */ |
| elapsed = (jiffies - fc->start_time) / HZ; |
| if (elapsed % (fc->up_interval + fc->down_interval) >= fc->up_interval) |
| return -EIO; |
| |
| flakey_map_bio(ti, bio); |
| |
| return DM_MAPIO_REMAPPED; |
| } |
| |
| static int flakey_status(struct dm_target *ti, status_type_t type, |
| char *result, unsigned int maxlen) |
| { |
| struct flakey_c *fc = ti->private; |
| |
| switch (type) { |
| case STATUSTYPE_INFO: |
| result[0] = '\0'; |
| break; |
| |
| case STATUSTYPE_TABLE: |
| snprintf(result, maxlen, "%s %llu %u %u", fc->dev->name, |
| (unsigned long long)fc->start, fc->up_interval, |
| fc->down_interval); |
| break; |
| } |
| return 0; |
| } |
| |
| static int flakey_ioctl(struct dm_target *ti, unsigned int cmd, unsigned long arg) |
| { |
| struct flakey_c *fc = ti->private; |
| struct dm_dev *dev = fc->dev; |
| int r = 0; |
| |
| /* |
| * Only pass ioctls through if the device sizes match exactly. |
| */ |
| if (fc->start || |
| ti->len != i_size_read(dev->bdev->bd_inode) >> SECTOR_SHIFT) |
| r = scsi_verify_blk_ioctl(NULL, cmd); |
| |
| return r ? : __blkdev_driver_ioctl(dev->bdev, dev->mode, cmd, arg); |
| } |
| |
| static int flakey_merge(struct dm_target *ti, struct bvec_merge_data *bvm, |
| struct bio_vec *biovec, int max_size) |
| { |
| struct flakey_c *fc = ti->private; |
| struct request_queue *q = bdev_get_queue(fc->dev->bdev); |
| |
| if (!q->merge_bvec_fn) |
| return max_size; |
| |
| bvm->bi_bdev = fc->dev->bdev; |
| bvm->bi_sector = flakey_map_sector(ti, bvm->bi_sector); |
| |
| return min(max_size, q->merge_bvec_fn(q, bvm, biovec)); |
| } |
| |
| static int flakey_iterate_devices(struct dm_target *ti, iterate_devices_callout_fn fn, void *data) |
| { |
| struct flakey_c *fc = ti->private; |
| |
| return fn(ti, fc->dev, fc->start, ti->len, data); |
| } |
| |
| static struct target_type flakey_target = { |
| .name = "flakey", |
| .version = {1, 1, 0}, |
| .module = THIS_MODULE, |
| .ctr = flakey_ctr, |
| .dtr = flakey_dtr, |
| .map = flakey_map, |
| .status = flakey_status, |
| .ioctl = flakey_ioctl, |
| .merge = flakey_merge, |
| .iterate_devices = flakey_iterate_devices, |
| }; |
| |
| static int __init dm_flakey_init(void) |
| { |
| int r = dm_register_target(&flakey_target); |
| |
| if (r < 0) |
| DMERR("register failed %d", r); |
| |
| return r; |
| } |
| |
| static void __exit dm_flakey_exit(void) |
| { |
| dm_unregister_target(&flakey_target); |
| } |
| |
| /* Module hooks */ |
| module_init(dm_flakey_init); |
| module_exit(dm_flakey_exit); |
| |
| MODULE_DESCRIPTION(DM_NAME " flakey target"); |
| MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>"); |
| MODULE_LICENSE("GPL"); |