/* * Copyright (C) 2001-2003 Sistina Software (UK) Limited. * * This file is released under the GPL. */ #include "dm.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 "linear" /* * Linear: maps a linear range of a device. */ struct linear_c { struct dm_dev *dev; sector_t start; }; /* * Construct a linear mapping: <dev_path> <offset> */ static int linear_ctr(struct dm_target *ti, unsigned int argc, char **argv) { struct linear_c *lc; unsigned long long tmp; if (argc != 2) { ti->error = "Invalid argument count"; return -EINVAL; } lc = kmalloc(sizeof(*lc), GFP_KERNEL); if (lc == NULL) { ti->error = "dm-linear: Cannot allocate linear context"; return -ENOMEM; } if (sscanf(argv[1], "%llu", &tmp) != 1) { ti->error = "dm-linear: Invalid device sector"; goto bad; } lc->start = tmp; if (dm_get_device(ti, argv[0], lc->start, ti->len, dm_table_get_mode(ti->table), &lc->dev)) { ti->error = "dm-linear: Device lookup failed"; goto bad; } ti->private = lc; return 0; bad: kfree(lc); return -EINVAL; } static void linear_dtr(struct dm_target *ti) { struct linear_c *lc = (struct linear_c *) ti->private; dm_put_device(ti, lc->dev); kfree(lc); } static int linear_map(struct dm_target *ti, struct bio *bio, union map_info *map_context) { struct linear_c *lc = (struct linear_c *) ti->private; bio->bi_bdev = lc->dev->bdev; bio->bi_sector = lc->start + (bio->bi_sector - ti->begin); return DM_MAPIO_REMAPPED; } static int linear_status(struct dm_target *ti, status_type_t type, char *result, unsigned int maxlen) { struct linear_c *lc = (struct linear_c *) ti->private; switch (type) { case STATUSTYPE_INFO: result[0] = '\0'; break; case STATUSTYPE_TABLE: snprintf(result, maxlen, "%s %llu", lc->dev->name, (unsigned long long)lc->start); break; } return 0; } static int linear_ioctl(struct dm_target *ti, struct inode *inode, struct file *filp, unsigned int cmd, unsigned long arg) { struct linear_c *lc = (struct linear_c *) ti->private; struct block_device *bdev = lc->dev->bdev; struct file fake_file = {}; struct dentry fake_dentry = {}; fake_file.f_mode = lc->dev->mode; fake_file.f_path.dentry = &fake_dentry; fake_dentry.d_inode = bdev->bd_inode; return blkdev_driver_ioctl(bdev->bd_inode, &fake_file, bdev->bd_disk, cmd, arg); } static struct target_type linear_target = { .name = "linear", .version= {1, 0, 2}, .module = THIS_MODULE, .ctr = linear_ctr, .dtr = linear_dtr, .map = linear_map, .status = linear_status, .ioctl = linear_ioctl, }; int __init dm_linear_init(void) { int r = dm_register_target(&linear_target); if (r < 0) DMERR("register failed %d", r); return r; } void dm_linear_exit(void) { int r = dm_unregister_target(&linear_target); if (r < 0) DMERR("unregister failed %d", r); }