mirror of
git://sourceware.org/git/lvm2.git
synced 2025-01-23 02:05:07 +03:00
fd36a66ccc
o Only one list of block devices for all tables o Locking to ensure that block devices only get opened once o Block device handling is now in dm-blkdev.c o We open block devices when we create the tables and hold them open until the table is destroyed (this prevents the module for the device being unloaded after table parsing and before the table is used) o We compute the hardsect size when the table is created rather than when someone requests it. Still to fix/change: o Probably want to hash the device lists in dm-blkdev.c and also remove refs to struct dm_bdev outside this file. o Need to ensure that hardsect_size doesn't change when new tables are swapped in (maybe this ought to be a per volume parameter and the tables will only parse if they match the value for the volume?). Things are changing fast here, so if you want a stable version of thic code try checking out yesterdays.
153 lines
3.3 KiB
C
153 lines
3.3 KiB
C
/*
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* dm-linear.c
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*
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* Copyright (C) 2001 Sistina Software
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*
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* This software is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2, or (at
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* your option) any later version.
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*
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* This software is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with GNU CC; see the file COPYING. If not, write to
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* the Free Software Foundation, 59 Temple Place - Suite 330,
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* Boston, MA 02111-1307, USA.
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*/
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#include <linux/config.h>
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/slab.h>
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#include <linux/fs.h>
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#include <linux/blkdev.h>
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#include <linux/device-mapper.h>
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#include "dm.h"
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/*
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* linear: maps a linear range of a device.
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*/
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struct linear_c {
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kdev_t rdev;
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long delta; /* FIXME: we need a signed offset type */
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struct dm_bdev *bdev;
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};
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/*
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* construct a linear mapping.
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* <dev_path> <offset>
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*/
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static int linear_ctr(struct dm_table *t, offset_t b, offset_t l,
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struct text_region *args, void **result,
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dm_error_fn fn, void *private)
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{
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struct linear_c *lc;
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unsigned int start;
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char path[256];
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struct text_region word;
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struct dm_bdev *bdev;
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int rv = 0;
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int hardsect_size;
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if (!dm_get_word(args, &word)) {
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fn("couldn't get device path", private);
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return -EINVAL;
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}
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dm_txt_copy(path, sizeof(path) - 1, &word);
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bdev = dm_blkdev_get(path);
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if (IS_ERR(bdev)) {
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fn("no such device", private);
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return PTR_ERR(bdev);
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}
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if (!dm_get_number(args, &start)) {
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fn("destination start not given", private);
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rv = -EINVAL;
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goto out_bdev_put;
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}
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if (!(lc = kmalloc(sizeof(lc), GFP_KERNEL))) {
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fn("couldn't allocate memory for linear context\n", private);
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rv = -ENOMEM;
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goto out_bdev_put;
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}
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lc->rdev = dm_bdev2rdev(bdev);
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lc->bdev = bdev;
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lc->delta = (int) start - (int) b;
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hardsect_size = get_hardsect_size(lc->rdev);
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if (t->hardsect_size > hardsect_size);
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t->hardsect_size = hardsect_size;
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*result = lc;
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return 0;
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out_bdev_put:
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dm_blkdev_put(bdev);
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return rv;
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}
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static void linear_dtr(struct dm_table *t, void *c)
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{
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struct linear_c *lc = (struct linear_c *) c;
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dm_blkdev_put(lc->bdev);
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kfree(c);
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}
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static int linear_map(struct buffer_head *bh, void *context)
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{
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struct linear_c *lc = (struct linear_c *) context;
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bh->b_rdev = lc->rdev;
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bh->b_rsector = bh->b_rsector + lc->delta;
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return 1;
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}
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static struct target_type linear_target = {
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name: "linear",
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module: THIS_MODULE,
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ctr: linear_ctr,
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dtr: linear_dtr,
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map: linear_map,
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};
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static int __init linear_init(void)
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{
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int rv;
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rv = dm_register_target(&linear_target);
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if (rv < 0) {
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printk(KERN_ERR "Device mapper: Linear: register failed %d\n", rv);
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}
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return rv;
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}
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static void __exit linear_exit(void)
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{
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int rv;
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rv = dm_unregister_target(&linear_target);
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if (rv < 0) {
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printk(KERN_ERR "Device mapper: Linear: unregister failed %d\n", rv);
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}
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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_AUTHOR("Joe Thornber <thornber@uk.sistina.com>");
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MODULE_DESCRIPTION("Device Mapper: Linear mapping");
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MODULE_LICENSE("GPL");
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