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Joe Thornber 2001-08-20 08:03:02 +00:00
parent c34ef2dc3c
commit 05434129e0
6 changed files with 603 additions and 791 deletions
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775
driver/device-mapper/device-mapper.c
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@ -1,775 +0,0 @@
/*
* device-mapper.c
*
* Copyright (C) 2001 Sistina Software
*
* This software is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2, or (at
* your option) any later version.
*
* This software is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with GNU CC; see the file COPYING. If not, write to
* the Free Software Foundation, 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*/
/*
* Changelog
*
* 14/08/2001 - First Version [Joe Thornber]
*/
/* TODO:
*
* dm_ctr_fn should provide the sector sizes, and hardsector_sizes set
* to the smallest of these.
*/
#include <linux/version.h>
#include <linux/major.h>
#include <linux/iobuf.h>
#include <linux/module.h>
#include <linux/fs.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <linux/compatmac.h>
#include <linux/cache.h>
#include <linux/device-mapper.h>
/*
* defines for blk.h
*/
#define MAJOR_NR DM_BLK_MAJOR
#define DEVICE_OFF(device)
#define LOCAL_END_REQUEST
#define MAX_DEPTH 16
#define NODE_SIZE L1_CACHE_BYTES
#define KEYS_PER_NODE (NODE_SIZE / sizeof(offset_t))
#include <linux/blk.h>
/*
* This driver attempts to provide a generic way of specifying logical
* devices which are mapped onto other devices.
*
* It does this by mapping sections of the logical device onto 'targets'.
*
* When the logical device is accessed the make_request function looks up
* the correct target for the given sector, and then asks this target
* to do the remapping.
*
* A btree like structure is used to hold the sector range -> target
* mapping. Because we know all the entries in the btree in advance
* we can make a very compact tree, omitting pointers to child nodes,
* (child nodes locations can be calculated). Each node of the btree is
* 1 level cache line in size, this gives a small performance boost.
*
* A userland test program for the btree gave the following results on a
* 1 Gigahertz Athlon machine:
*
* entries in btree lookups per second
* ---------------- ------------------
* 5 25,000,000
* 1000 7,700,000
* 10,000,000 3,800,000
*
* Of course these results should be taken with a pinch of salt; the lookups
* were sequential and there were no other applications (other than X + emacs)
* running to give any pressure on the level 1 cache.
*
* Typically LVM users would find they have very few targets for each
* LV (probably less than 10).
*
* Target types are not hard coded, instead the
* 'register_mapping_type' function should be called. A target type
* is specified using three functions (see the header):
*
* dm_ctr_fn - takes a string and contructs a target specific piece of
* context data.
* dm_dtr_fn - destroy contexts.
* dm_map_fn - function that takes a buffer_head and some previously
* constructed context and performs the remapping.
*
* This file contains two trivial mappers, which are automatically registered:
* 'linear', and 'io_error'. Linear alone would be enough to implement most
* LVM features (omitting striped volumes and snapshots).
*
* At the moment this driver has a temporary ioctl interface, but I will
* move this to a read/write interface on either a /proc file or a
* char device. This will allow scripts to simply cat a text mapping
* table in order to set up a volume.
*
* At the moment the table assumes 32 bit keys (sectors), the move to
* 64 bits will involve no interface changes, since the tables wil be
* read in as ascii data. A different table implementation can
* therefor be provided at another time. Either just by changing offset_t
* to 64 bits, or maybe implementing a structure which looks up the keys in
* stages (ie, 32 bits at a time).
*
* More interesting targets:
*
* striped mapping; given a stripe size and a number of device regions
* this would stripe data across the regions. Especially useful, since
* we could limit each striped region to a 32 bit area and then avoid
* nasy 64 bit %'s.
*
* mirror mapping (reflector ?); would set off a kernel thread slowly
* copying data from one region to another, ensuring that any new
* writes got copied to both destinations correctly. Great for
* implementing pvmove. Not sure how userland would be notified that
* the copying process had completed.
*/
#define MAX_DEVICES 64
#define DEFAULT_READ_AHEAD 64
#define WARN(f, x...) printk(KERN_WARNING "%s " f, _name , ## x)
const char *_name = "device-mapper";
int _version[3] = {1, 0, 0};
struct mapper {
char *name;
dm_ctr_fn ctr;
dm_dtr_fn dtr;
dm_map_fn map;
struct mapper *next;
};
struct mapped_device {
int in_use;
spinlock_t lock;
kdev_t dev;
atomic_t pending;
int depth;
int counts[MAX_DEPTH]; /* in nodes */
offset_t *index[MAX_DEPTH];
int num_targets;
dm_map_fn *targets;
void **contexts;
};
static int _dev_count = 0;
static struct mapped_device _devices[MAX_DEVICES];
static spinlock_t _mappers_lock = SPIN_LOCK_UNLOCKED;
static struct mapper *_mappers;
/* block device arrays */
static int _block_size[MAX_DEVICES];
static int _blksize_size[MAX_DEVICES];
static int _hardsect_size[MAX_DEVICES];
static int _ctl_open(struct inode *inode, struct file *file);
static int _ctl_close(struct inode *inode, struct file *file);
static int _ctl_ioctl(struct inode *inode, struct file *file,
uint command, ulong a);
static struct file_operations _ctl_fops = {
open: _ctl_open,
release: _ctl_close,
ioctl: _ctl_ioctl,
};
static int _blk_open(struct inode *inode, struct file *file);
static int _blk_close(struct inode *inode, struct file *file);
static int _blk_ioctl(struct inode *inode, struct file *file,
uint command, ulong a);
static struct block_device_operations _blk_dops = {
open: _blk_open,
release: _blk_close,
ioctl: _blk_ioctl
};
static void _init_mds(void);
static struct mapped_device *_build_map(struct device_table *t);
static int _request_fn(request_queue_t *q, int rw, struct buffer_head *bh);
static int _register_std_targets(void);
static struct mapped_device *_get_free_md(void);
static void _put_free_md(struct mapped_device *md);
static int _setup_targets(struct mapped_device *md, struct device_table *t);
static int _setup_btree(struct mapped_device *md, struct device_table *t);
static int _setup_btree_index(int l, struct mapped_device *md);
struct mapper *_find_mapper(const char *name);
/*
* setup and teardown the driver
*/
static int _init(void)
{
_init_mds();
if (!_register_std_targets())
return -EIO; /* FIXME: better error value */
/* set up the arrays */
read_ahead[MAJOR_NR] = DEFAULT_READ_AHEAD;
blk_size[MAJOR_NR] = _block_size;
blksize_size[MAJOR_NR] = _blksize_size;
hardsect_size[MAJOR_NR] = _hardsect_size;
if (register_chrdev(DM_CTL_MAJOR, _name, &_ctl_fops) < 0) {
printk(KERN_ERR "%s - register_chrdev failed\n", _name);
return -EIO;
}
if (register_blkdev(MAJOR_NR, _name, &_blk_dops) < 0) {
printk(KERN_ERR "%s -- register_blkdev failed\n", _name);
if (unregister_chrdev(DM_CTL_MAJOR, _name) < 0)
printk(KERN_ERR "%s - unregister_chrdev failed\n",
_name);
return -EIO;
}
blk_queue_make_request(BLK_DEFAULT_QUEUE(MAJOR_NR), _request_fn);
printk(KERN_INFO "%s(%d, %d, %d) successfully initialised\n", _name,
_version[0], _version[1], _version[2]);
return 0;
}
static void _fin(void)
{
if (unregister_chrdev(DM_CTL_MAJOR, _name) < 0)
printk(KERN_ERR "%s - unregister_chrdev failed\n", _name);
if (unregister_blkdev(MAJOR_NR, _name) < 0)
printk(KERN_ERR "%s -- unregister_blkdev failed\n", _name);
read_ahead[MAJOR_NR] = 0;
blk_size[MAJOR_NR] = 0;
blksize_size[MAJOR_NR] = 0;
hardsect_size[MAJOR_NR] = 0;
printk(KERN_INFO "%s(%d, %d, %d) successfully finalised\n", _name,
_version[0], _version[1], _version[2]);
}
/*
* character device fns
*/
static int _ctl_open(struct inode *inode, struct file *file)
{
if (!capable(CAP_SYS_ADMIN))
return -EACCES;
MOD_INC_USE_COUNT;
return 0;
}
static int _ctl_close(struct inode *inode, struct file *file)
{
MOD_DEC_USE_COUNT;
return 0;
}
static int _ctl_ioctl(struct inode *inode, struct file *file,
uint command, ulong a)
{
struct device_table info;
if (copy_from_user(&info, (void *) a, sizeof(info)))
return -EFAULT;
switch (command) {
case MAPPED_DEVICE_CREATE:
/* FIXME: copy arrays */
_build_map(&info);
break;
case MAPPED_DEVICE_DESTROY:
/* FIXME: finish */
break;
default:
printk(KERN_WARNING "%s -- _ctl_ioctl: unknown command 0x%x\n",
_name, command);
return -EINVAL;
}
return 0;
}
/*
* block device functions
*/
static int _blk_open(struct inode *inode, struct file *file)
{
int minor = MINOR(inode->i_rdev);
struct mapped_device *md = _devices + minor;
if (minor >= MAX_DEVICES)
return -ENXIO;
spin_lock(&md->lock);
if (!md->in_use) {
spin_unlock(&md->lock);
return -ENXIO;
}
md->in_use++;
spin_unlock(&md->lock);
MOD_INC_USE_COUNT;
return 0;
}
static int _blk_close(struct inode *inode, struct file *file)
{
int minor = MINOR(inode->i_rdev);
struct mapped_device *md = _devices + minor;
if (minor >= MAX_DEVICES)
return -ENXIO;
spin_lock(&md->lock);
if (md->in_use <= 1) {
WARN("reference count in mapped_device incorrect\n");
spin_unlock(&md->lock);
return -ENXIO;
}
md->in_use--;
spin_unlock(&md->lock);
MOD_INC_USE_COUNT;
return 0;
}
static int _blk_ioctl(struct inode *inode, struct file *file,
uint command, ulong a)
{
/* FIXME: check in the latest Rubini that all expected ioctl's
are supported */
int minor = MINOR(inode->i_rdev);
long size;
switch (command) {
case BLKGETSIZE:
size = _block_size[minor] * 1024 / _hardsect_size[minor];
if (copy_to_user((void *) a, &size, sizeof(long)))
return -EFAULT;
break;
case BLKFLSBUF:
if (!capable(CAP_SYS_ADMIN))
return -EACCES;
fsync_dev(inode->i_rdev);
invalidate_buffers(inode->i_rdev);
return 0;
case BLKRAGET:
if (copy_to_user((void *) a, &read_ahead[MAJOR(inode->i_rdev)],
sizeof(long)))
return -EFAULT;
return 0;
case BLKRASET:
if (!capable(CAP_SYS_ADMIN))
return -EACCES;
read_ahead[MAJOR(inode->i_rdev)] = a;
return 0;
case BLKRRPART:
return -EINVAL;
default:
printk(KERN_WARNING "%s - unknown block ioctl %d\n",
_name, command);
return -EINVAL;
}
return 0;
}
static int _request_fn(request_queue_t *q, int rw, struct buffer_head *bh)
{
struct mapped_device *md;
offset_t *node;
int i = 0, l, next_node = 0, ret = 0;
int minor = MINOR(bh->b_dev);
dm_map_fn fn;
void *context;
if (minor >= MAX_DEVICES)
return -ENXIO;
md = _devices + minor;
if (MINOR(md->dev != minor))
return -ENXIO;
for (l = 0; l < md->depth; l++) {
next_node = ((KEYS_PER_NODE + 1) * next_node) + i;
node = md->index[l] + (next_node * KEYS_PER_NODE);
for (i = 0; i < KEYS_PER_NODE; i++)
if (node[i] >= bh->b_rsector)
break;
}
next_node = (KEYS_PER_NODE * next_node) + i;
fn = md->targets[next_node];
context = md->contexts[next_node];
if (fn) {
if ((ret = fn(bh, context)))
atomic_inc(&md->pending);
} else
buffer_IO_error(bh);
return ret;
}
static struct mapped_device *_build_map(struct device_table *t)
{
struct mapped_device *md = _get_free_md();
if (!md)
return 0;
if (!_setup_targets(md, t))
goto bad;
if (!_setup_btree(md, t))
goto bad;
return md;
bad:
_put_free_md(md);
return 0;
}
static inline void *__aligned(size_t s, unsigned int align)
{
return vmalloc(s);
}
static inline void __free_aligned(void *ptr)
{
vfree(ptr);
}
static int _setup_targets(struct mapped_device *md, struct device_table *t)
{
int i;
offset_t low = 0;
md->num_targets = t->count;
md->targets = __aligned(sizeof(*md->targets) * md->num_targets,
NODE_SIZE);
for (i = 0; i < md->num_targets; i++) {
struct mapper *m = _find_mapper(t->map[i].type);
if (!m)
return 0;
if (!m->ctr(low, t->map[i].high + 1,
t->map[i].context, md->contexts + i)) {
WARN("contructor for '%s' failed\n", m->name);
return 0;
}
md->targets[i] = m->map;
}
return 1;
}
static inline ulong _round_up(ulong n, ulong size)
{
ulong r = n % size;
return ((n / size) + (r ? 1 : 0)) * size;
}
static inline ulong _div_up(ulong n, ulong size)
{
return _round_up(n, size) / size;
}
static int _setup_btree(struct mapped_device *md, struct device_table *t)
{
int n, i;
offset_t *k;
/* how many indexes will the btree have ? */
for (n = _div_up(md->num_targets, KEYS_PER_NODE), i = 1; n != 1; i++)
n = _div_up(n, KEYS_PER_NODE + 1);
md->depth = i;
md->counts[md->depth - 1] = _div_up(md->num_targets, KEYS_PER_NODE);
while (--i)
md->counts[i - 1] = _div_up(md->counts[i], KEYS_PER_NODE + 1);
for (i = 0; i < md->depth; i++) {
size_t s = NODE_SIZE * md->counts[i];
md->index[i] = __aligned(s, NODE_SIZE);
memset(md->index[i], -1, s);
}
/* bottom layer is easy */
for (k = md->index[md->depth - 1], i = 0; i < md->num_targets; i++)
k[i] = t->map[i].high;
/* fill in higher levels */
for (i = md->depth - 1; i; i--)
_setup_btree_index(i - 1, md);
return 1;
}
static offset_t __high(struct mapped_device *md, int l, int n)
{
while (1) {
if (n >= md->counts[l])
return (offset_t) -1;
if (l == md->depth - 1)
return md->index[l][((n + 1) * KEYS_PER_NODE) - 1];
l++;
n = (n + 1) * (KEYS_PER_NODE + 1) - 1;
}
}
static int _setup_btree_index(int l, struct mapped_device *md)
{
int n, c, cn;
for (n = 0, cn = 0; n < md->counts[l]; n++) {
offset_t *k = md->index[l] + (n * KEYS_PER_NODE);
for (c = 0; c < KEYS_PER_NODE; c++)
k[c] = __high(md, l + 1, cn++);
cn++;
}
return 1;
}
static void _init_mds(void)
{
int i;
_dev_count = 0;
memset(_devices, 0, sizeof(_devices));
for (i = 0; i < MAX_DEVICES; i++) {
_devices[i].lock = SPIN_LOCK_UNLOCKED;
_devices[i].dev = MKDEV(MAJOR_NR, i);
}
}
static struct mapped_device *_get_free_md(void)
{
int i;
struct mapped_device *m;
for (i = 0; i < MAX_DEVICES; i++) {
m = _devices + i;
spin_lock(&m->lock);
if (!m->in_use) {
m->in_use = 1;
spin_unlock(m);
return m;
}
spin_unlock(&m->lock);
}
WARN("no free devices available\n");
return 0;
}
static void _put_free_md(struct mapped_device *md)
{
int i;
spin_lock(&md->lock);
for (i = 0; i < md->depth; i++)
__free_aligned(md->index[i]);
__free_aligned(md->targets);
__free_aligned(md->contexts);
/* FIXME: check this is the correct length */
memset(&md->depth, 0,
sizeof(*md) - ((void *) &md->depth - (void *) md));
md->in_use = 0;
spin_unlock(&md->lock);
}
int register_mapping_type(const char *name, dm_ctr_fn ctr,
dm_dtr_fn dtr, dm_map_fn map)
{
struct mapper *m;
if (_find_mapper(name)) {
WARN("mapper(%s) already registered\n", name);
return -1; /* FIXME: what's a good return value ? */
}
/* FIXME: There's a race between the last check and insertion */
if ((m = kmalloc(sizeof(*m) + strlen(name) + 1, GFP_KERNEL))) {
WARN("couldn't allocate memory for mapper\n");
return -ENOMEM;
}
m->name = (char *) (m + 1);
m->ctr = ctr;
m->dtr = dtr;
m->map = map;
spin_lock(&_mappers_lock);
m->next = _mappers;
_mappers = m;
spin_unlock(&_mappers_lock);
return 0;
}
struct mapper *_find_mapper(const char *name)
{
struct mapper *m;
spin_lock(&_mappers_lock);
for (m = _mappers; m && strcmp(m->name, name); m = m->next)
;
spin_unlock(&_mappers_lock);
return m;
}
/*
* now for a couple of simple targets:
*
* 'io-err' target always fails an io, useful for bringing up LV's
* that have holes in them.
*
* 'linear' target maps a linear range of a device
*/
int _io_err_ctr(offset_t b, offset_t e, const char *context, void **result)
{
/* this takes no arguments */
*result = 0;
return 1;
}
void _io_err_dtr(void *c)
{
/* empty */
}
int _io_err_map(struct buffer_head *bh, void *context)
{
buffer_IO_error(bh);
return 0;
}
struct linear_c {
kdev_t dev;
int offset; /* FIXME: we need a signed offset type */
};
int _linear_ctr(offset_t b, offset_t e, const char *context, void **result)
{
/* context string should be of the form:
* <major> <minor> <offset>
*/
char *ptr = (char *) context;
struct linear_c *lc;
int major, minor, start;
/* FIXME: somewhat verbose */
major = simple_strtol(context, &ptr, 10);
if (ptr == context)
return 0;
context = ptr;
minor = simple_strtol(context, &ptr, 10);
if (ptr == context)
return 0;
context = ptr;
start = simple_strtoul(context, &ptr, 10);
if (ptr == context)
return 0;
if (!(lc = kmalloc(sizeof(lc), GFP_KERNEL))) {
WARN("couldn't allocate memory for linear context\n");
return 0;
}
lc->dev = MKDEV(major, minor);
lc->offset = start - b;
/* FIXME: we should open the PV */
*result = lc;
return 1;
}
void _linear_dtr(void *c)
{
kfree(c);
}
int _linear_map(struct buffer_head *bh, void *context)
{
struct linear_c *lc = (struct linear_c *) context;
bh->b_rdev = lc->dev;
bh->b_rsector = bh->b_rsector + lc->offset;
return 1;
}
static int _register_std_targets(void)
{
int ret;
#define xx(n, fn) \
if ((ret = register_mapping_type(n, \
fn ## _ctr, fn ## _dtr, fn ## _map) < 0)) return ret
xx("io-err", _io_err);
xx("linear", _linear);
#undef xx
return 0;
}
/*
* module hooks
*/
module_init(_init);
module_exit(_fin);
/*
* Local variables:
* c-file-style: "linux"
* End:
*/

25
driver/device-mapper/device-mapper.h
View File

@ -34,24 +34,17 @@
#define DM_BLK_MAJOR LVM_BLK_MAJOR
#define DM_CTL_MAJOR LVM_CHAR_MAJOR
#define DM_NAME_LEN 64
typedef unsigned int offset_t;
struct device_map {
offset_t high;
const char *type;
const char *context;
struct dm_request {
int minor; /* -1 indicates no preference */
char name[DM_NAME_LEN];
};
struct device_table {
unsigned int minor;
unsigned int major;
unsigned long count;
struct device_map *map;
};
#define MAPPED_DEVICE_CREATE _IOWR(DM_CTL_MAJOR, 0, struct device_table)
#define MAPPED_DEVICE_DESTROY _IOW(DM_CTL_MAJOR, 1, struct device_table)
#define MAPPED_DEVICE_CREATE _IOWR(DM_CTL_MAJOR, 0, struct dm_request)
#define MAPPED_DEVICE_DESTROY _IOW(DM_CTL_MAJOR, 1, struct dm_request)
#ifdef __KERNEL__
typedef int (*dm_ctr_fn)(offset_t b, offset_t e,
@ -59,8 +52,8 @@ typedef int (*dm_ctr_fn)(offset_t b, offset_t e,
typedef void (*dm_dtr_fn)(void *c);
typedef int (*dm_map_fn)(struct buffer_head *bh, void *context);
int register_mapping_type(const char *name, dm_ctr_fn ctr, dm_dtr_fn dtr,
dm_map_fn map);
int register_map_target(const char *name, dm_ctr_fn ctr, dm_dtr_fn dtr,
dm_map_fn map);
#endif
#endif

207
driver/device-mapper/dm-fs.c Normal file
View File

@ -0,0 +1,207 @@
/*
* dm.c
*
* Copyright (C) 2001 Sistina Software
*
* This software is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2, or (at
* your option) any later version.
*
* This software is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with GNU CC; see the file COPYING. If not, write to
* the Free Software Foundation, 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*/
/*
* procfs and devfs handling for device mapper
*
* Changelog
*
* 16/08/2001 - First version [Joe Thornber]
*/
#include "dm.h"
/*
* /dev/device-mapper/control is the control char device used to
* create/destroy mapping devices.
*
* When a mapping device called <name> is created it appears as
* /dev/device-mapper/<name>. In addition the interface to control the
* mapping will appear in /proc/device-mapper/<name>.
*/
const char *_fs_dir = "device-mapper";
static struct proc_dir_entry *_proc_dir;
static devfs_handle_t _dev_dir;
static devfs_handle_t _dev_control;
int dm_init_fs()
{
/* create /dev/device-manager */
_dev_dir = devfs_mk_dir(0, _fs_dir, NULL);
/* and put the control device in it */
_dev_control = devfs_register(0 , "device-mapper", 0, DM_CHAR_MAJOR, 0,
S_IFCHR | S_IRUSR | S_IWUSR | S_IRGRP,
&dm_ctl_fops, NULL);
if (!(_proc_dir = create_proc_entry(_fs_dir, S_IFDIR, &proc_root))) {
devfs_unregister(_dm_control);
_dm_control = 0;
return 0;
}
return 1;
}
void dm_fin_fs(void)
{
/* FIXME: unregister all devices and proc interfaces */
devfs_unregister(_dev_control);
devfs_unregister(_dev_dir);
remove_proc_entry(_fs_dir, &proc_root);
}
int dm_add(const char *name)
{
}
int dm_remove(const char *name)
{
}
static int _setup_targets(struct mapped_device *md, struct device_table *t)
{
int i;
offset_t low = 0;
md->num_targets = t->count;
md->targets = __aligned(sizeof(*md->targets) * md->num_targets,
NODE_SIZE);
for (i = 0; i < md->num_targets; i++) {
struct mapper *m = _find_mapper(t->map[i].type);
if (!m)
return 0;
if (!m->ctr(low, t->map[i].high + 1,
t->map[i].context, md->contexts + i)) {
WARN("contructor for '%s' failed", m->name);
return 0;
}
md->targets[i] = m->map;
}
return 1;
}
static const char *_eat_white(const char *b, const char *e)
{
while(b != e && isspace((int) *b))
b++;
return b;
}
static int _get_line(const char *b, const char *e,
const char **lb, const char **le)
{
b = _eat_white(b, e);
if (b == e)
return 0;
lb = b;
while((b != e) && *b != '\n')
b++;
if (b == e) {
/* FIXME: handle partial lines */
return 0;
}
*le = b;
return 1;
}
static int _process_line(const char *b, const char *e)
{
struct target *t;
const char *wb, *we;
char buffer[64];
int len;
/*
* format of a line is:
* <highest valid sector> <target name> <target args>
*/
if (!_get_word(b, e, &wb, &we) || (we - wb) > sizeof(buffer))
return -EPARAM;
len = we - wb;
strncpy(buffer, wb, we - wb);
buffer[len] = '\0';
if (!(t = get_target(buffer))) {
/* FIXME: add module loading here */
return -EPARAM;
}
}
static int _write_proc(struct file *file, const char *buffer,
unsigned long *count, void *data)
{
const char *b, *e, *lb, *le;
int minor = (int) data;
struct mapped_device *md = dm_get_dev(minor);
if (!md)
return -ENXIO;
b = buffer;
e = buffer + e;
if (!is_loading(md)) {
if (!_get_line(b, e, &lb, &le))
return -EPARAM;
if (tokcmp("begin\n", lb, le))
return -EPARAM;
start_loading(md);
b = le;
}
while(_get_line(b, e, &lb, &le)) {
if (!tokcmp("end\n", wb, we)) {
/* FIXME: finish */
}
ret = _process_line(lb, le);
if (ret < 0)
goto fail;
b = le;
}
fail:
/* stop the table load */
}

112
driver/device-mapper/dm-table.c Normal file
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/*
* dm-table.c
*
* Copyright (C) 2001 Sistina Software
*
* This software is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2, or (at
* your option) any later version.
*
* This software is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with GNU CC; see the file COPYING. If not, write to
* the Free Software Foundation, 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*/
/*
* Changelog
*
* 16/08/2001 - First version [Joe Thornber]
*/
static inline ulong _round_up(ulong n, ulong size)
{
ulong r = n % size;
return n + (r ? (size - r) : 0);
}
static inline ulong _div_up(ulong n, ulong size)
{
return _round_up(n, size) / size;
}
static offset_t _high(struct mapped_device *md, int l, int n)
{
while (1) {
if (n >= md->counts[l])
return (offset_t) -1;
if (l == md->depth - 1)
return md->index[l][((n + 1) * KEYS_PER_NODE) - 1];
l++;
n = (n + 1) * (KEYS_PER_NODE + 1) - 1;
}
}
static int _setup_btree_index(int l, struct mapped_device *md)
{
int n, c, cn;
for (n = 0, cn = 0; n < md->counts[l]; n++) {
offset_t *k = md->index[l] + (n * KEYS_PER_NODE);
for (c = 0; c < KEYS_PER_NODE; c++)
k[c] = _high(md, l + 1, cn++);
cn++;
}
return 1;
}
struct mapped_device *dm_build_btree(struct mapped_device *md)
{
int n, i;
offset_t *k;
/* how many indexes will the btree have ? */
for (n = _div_up(md->num_targets, KEYS_PER_NODE), i = 1; n != 1; i++)
n = _div_up(n, KEYS_PER_NODE + 1);
md->depth = i;
md->counts[md->depth - 1] = _div_up(md->num_targets, KEYS_PER_NODE);
while (--i)
md->counts[i - 1] = _div_up(md->counts[i], KEYS_PER_NODE + 1);
for (i = 0; i < md->depth; i++) {
size_t s = NODE_SIZE * md->counts[i];
md->index[i] = __aligned(s, NODE_SIZE);
memset(md->index[i], -1, s);
}
/* bottom layer is easy */
for (k = md->index[md->depth - 1], i = 0; i < md->num_targets; i++)
k[i] = t->map[i].high;
/* fill in higher levels */
for (i = md->depth - 1; i; i--)
_setup_btree_index(i - 1, md);
return 1;
}
void dm_free_btree(struct mapped_device *md)
{
int i;
for (i = 0; i < md->depth; i++)
__free_aligned(md->index[i]);
__free_aligned(md->targets);
__free_aligned(md->contexts);
}

174
driver/device-mapper/dm-target.c Normal file
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/*
* dm-target.c
*
* Copyright (C) 2001 Sistina Software
*
* This software is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2, or (at
* your option) any later version.
*
* This software is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with GNU CC; see the file COPYING. If not, write to
* the Free Software Foundation, 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*/
/*
* 16/08/2001 - First Version [Joe Thornber]
*/
#include "dm.h"
static struct target *_targets;
static spinlock_t _lock = SPIN_LOCK_UNLOCKED;
struct target *__get_target(const char *name)
{
struct target *t;
for (t = _targets; t && strcmp(t->name, name); t = t->next)
;
return t;
}
struct target *dm_get_target(const char *name)
{
struct target *t;
spin_lock(&_lock);
t = __get_target(name);
spin_unlock(&_lock);
return t;
}
int register_map_target(const char *name, dm_ctr_fn ctr,
dm_dtr_fn dtr, dm_map_fn map)
{
struct target *t = kmalloc(sizeof(*m) + strlen(name) + 1, GFP_KERNEL);
if (!t)
return -ENOMEM;
spin_lock(&_lock);
if (__get_target(name)) {
WARN("mapper(%s) already registered\n", name);
spin_unlock(&_lock);
return -1; /* FIXME: what's a good return value ? */
}
t->name = (char *) (t + 1);
t->ctr = ctr;
t->dtr = dtr;
t->map = map;
t->next = _targets;
_targets = t;
spin_unlock(&_lock);
return 0;
}
/*
* now for a couple of simple targets:
*
* 'io-err' target always fails an io, useful for bringing up LV's
* that have holes in them.
*
* 'linear' target maps a linear range of a device
*/
int _io_err_ctr(offset_t b, offset_t e, const char *context, void **result)
{
/* this takes no arguments */
*result = 0;
return 1;
}
void _io_err_dtr(void *c)
{
/* empty */
}
int _io_err_map(struct buffer_head *bh, void *context)
{
buffer_IO_error(bh);
return 0;
}
struct linear_c {
kdev_t dev;
int offset; /* FIXME: we need a signed offset type */
};
int _linear_ctr(offset_t b, offset_t e, const char *context, void **result)
{
/* context string should be of the form:
* <major> <minor> <offset>
*/
char *ptr = (char *) context;
struct linear_c *lc;
int major, minor, start;
/* FIXME: somewhat verbose */
major = simple_strtol(context, &ptr, 10);
if (ptr == context)
return 0;
context = ptr;
minor = simple_strtol(context, &ptr, 10);
if (ptr == context)
return 0;
context = ptr;
start = simple_strtoul(context, &ptr, 10);
if (ptr == context)
return 0;
if (!(lc = kmalloc(sizeof(lc), GFP_KERNEL))) {
WARN("couldn't allocate memory for linear context\n");
return 0;
}
lc->dev = MKDEV(major, minor);
lc->offset = start - b;
/* FIXME: we should open the PV */
*result = lc;
return 1;
}
void _linear_dtr(void *c)
{
kfree(c);
}
int _linear_map(struct buffer_head *bh, void *context)
{
struct linear_c *lc = (struct linear_c *) context;
bh->b_rdev = lc->dev;
bh->b_rsector = bh->b_rsector + lc->offset;
return 1;
}
int dm_std_targets(void)
{
int ret;
#define xx(n, fn) \
if ((ret = register_mapping_type(n, \
fn ## _ctr, fn ## _dtr, fn ## _map) < 0)) return ret
xx("io-err", _io_err);
xx("linear", _linear);
#undef xx
return 0;
}

101
driver/device-mapper/dm.h Normal file
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/*
* dm.h
*
* Copyright (C) 2001 Sistina Software
*
* This software is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2, or (at
* your option) any later version.
*
* This software is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with GNU CC; see the file COPYING. If not, write to
* the Free Software Foundation, 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*/
/*
* Internal header file for device mapper
*
* Changelog
*
* 16/08/2001 - First version [Joe Thornber]
*/
#ifndef DM_INTERNAL_H
#define DM_INTERNAL_H
#define MAX_DEPTH 16
#define NODE_SIZE L1_CACHE_BYTES
#define KEYS_PER_NODE (NODE_SIZE / sizeof(offset_t))
enum {
DM_LOADING,
DM_CREATED,
DM_ACTIVE,
};
struct mapped_device {
kdev_t dev;
char name[DM_NAME_LEN];
int state;
atomic_t pending;
/* btree table */
int depth;
int counts[MAX_DEPTH]; /* in nodes */
offset_t *index[MAX_DEPTH];
int num_targets;
int num_allocated;
dm_map_fn *targets;
void **contexts;
/* used by dm-fs.c */
devfs_handle_t devfs_entry;
char incomplete_input[64];
};
/* dm-target.c */
struct target {
char *name;
dm_ctr_fn ctr;
dm_dtr_fn dtr;
dm_map_fn map;
struct target *next;
};
struct target *dm_get_target(const char *name);
int dm_std_targets(void);
/* dm.c */
/* dm-table.c */
int dm_build_btree(struct mapped_device *md);
/* dm-fs.c */
int dm_init_fs(void);
int dm_fin_fs(void);
/* misc. inlines */
static inline void *__aligned(size_t s, unsigned int align)
{
return vmalloc(s);
}
static inline void __free_aligned(void *ptr)
{
vfree(ptr);
}
#endif