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Date: Thu, 27 Jul 2006 14:48:40 -0700
From: Dan Smith <danms@...ibm.com>
To: "Alasdair G. Kergon" <agk@...hat.com>
Cc: device-mapper development <dm-devel@...hat.com>,
Ryan Grimm <grimm@...ibm.com>, linux-kernel@...r.kernel.org
Subject: [PATCH] device-mapper: Add userspace target
This patch adds a userspace target to device-mapper. This version
includes the following changes as requested:
- Removed debug messages
- Block device targets must be registered at table creation time
- Chardev operations check for root capabilities
- Eliminate the *need* to allocate memory on the critical IO path
- Broke up the interface between the kernel and the userspace library
- Insulated the consumer of libdevmapper from the details of
dm-userspace kernel interface, allowing for future expansion
without breaking compatibility
- Split dm-userspace.c into separate chunks (along the line between
the target-specific and userspace-transport pieces)
- Added synchronous IO completion notification and control to allow
userspace to enforce metadata consistency where needed.
A patch to libdevmapper for dm-userspace support will be sent to
dm-devel.
Signed-off-by: Dan Smith <danms@...ibm.com>
Signed-off-by: Ryan Grimm <grimm@...ibm.com>
diff -Naur linux-2.6.17.6-orig/drivers/md/dm-user.h linux-2.6.17.6-dmu/drivers/md/dm-user.h
--- linux-2.6.17.6-orig/drivers/md/dm-user.h 1969-12-31 16:00:00.000000000 -0800
+++ linux-2.6.17.6-dmu/drivers/md/dm-user.h 2006-07-27 14:32:05.000000000 -0700
@@ -0,0 +1,208 @@
+/*
+ * Copyright (C) International Business Machines Corp., 2006
+ * Author: Dan Smith <danms@...ibm.com>
+ *
+ * This program 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; under version 2 of the License.
+ *
+ * This program 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 this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ *
+ */
+
+#ifndef __DM_USER_H
+#define __DM_USER_H
+
+#define DMU_KEY_LEN 256
+
+extern struct target_type userspace_target;
+extern mempool_t *request_pool;
+extern dev_t dmu_dev;
+extern spinlock_t devices_lock;
+extern struct list_head devices;
+
+/*
+ * A hash table of remaps
+ */
+struct hash_table {
+ struct list_head *table; /* Array of lists (buckets) */
+ uint64_t size; /* Number of buckets */
+ uint32_t mask; /* Mask used to determine bucket */
+ uint64_t count; /* Number of remaps in entire table */
+};
+
+/*
+ * A block device that we can send bios to
+ */
+struct target_device {
+ struct list_head list; /* Our place in the targets list */
+ struct block_device *bdev; /* The target block_device */
+ struct kref users; /* Self-destructing reference count */
+};
+
+/*
+ * A dm-userspace device, which consists of multiple targets sharing a
+ * common key
+ */
+struct dmu_device {
+ struct list_head list; /* Our place in the devices list */
+
+ spinlock_t lock; /* Protects all the fields below */
+
+ struct list_head requests; /* List of pending requests */
+ struct list_head target_devs; /* List of devices we can target */
+ struct list_head in_flight; /* List of pending remaps */
+ struct hash_table remaps; /* Hash table of all our maps */
+
+ void *transport_private; /* Private data for userspace comms */
+
+ char key[DMU_KEY_LEN]; /* Unique name string for device */
+ struct kref users; /* Self-destructing reference count */
+
+ wait_queue_head_t wqueue; /* To block while waiting for reqs */
+
+ uint64_t block_size; /* Block size for this device */
+ uint64_t block_mask; /* Mask for offset in block */
+ unsigned int block_shift; /* Shift to convert to/from block */
+
+ struct kcopyd_client *kcopy; /* Interface to kcopyd */
+
+ uint32_t id_counter; /* Used to generate request IDs */
+};
+
+struct userspace_request {
+ struct list_head list; /* Our place on the request queue */
+
+ spinlock_t lock; /* Protects all the fields below */
+
+ struct dmu_device *dev; /* The DMU device that owns us */
+
+ int type; /* Type of request */
+ int sent; /* Non-zero if we've been sent */
+ uint32_t flags; /* Attribute flags */
+ uint32_t id; /* Unique ID for sync with userspace */
+ union {
+ struct bio_list bios; /* Bios waiting on this request */
+ uint64_t block; /* The block in question */
+ } u;
+ atomic_t refcnt; /* Reference count */
+};
+
+struct dmu_map {
+ struct list_head list; /* Our place in a remap bucket chain */
+ struct list_head mru_list; /* Our place on the MRU list */
+ struct list_head in_flight; /* Our place on the */
+
+ spinlock_t lock; /* Protects all the fields below */
+
+ uint64_t org_block; /* Original block */
+ uint64_t new_block; /* Destination block */
+ int64_t offset; /* Sectors to offset remapped block */
+ uint32_t flags; /* Attribute flags */
+ uint32_t id; /* Unique ID for sync with userspace */
+
+ struct target_device *src; /* Source blkdev for COPY_FIRST */
+ struct target_device *dest; /* Where the remapped block is */
+
+ struct bio_list bios; /* Bios queued for remapping */
+ struct bio_list bios_waiting; /* Bios waiting for endio sync */
+
+ struct dmu_device *dev; /* The DMU device that owns us */
+ struct dmu_map *next; /* Next remap that depends on us */
+};
+
+/* Find and grab a reference to a target device */
+struct target_device *find_target(struct dmu_device *dev,
+ dev_t devno);
+
+/* Object allocation, destruction, and initialization routines */
+void init_remap(struct dmu_device *dev, struct dmu_map *remap);
+void init_request(struct dmu_device *dev,
+ int type,
+ struct userspace_request *req);
+void free_remap(struct dmu_map *remap);
+void __free_remap(struct dmu_map *remap);
+struct dmu_map *alloc_remap_atomic(struct dmu_device *dev);
+
+/* Hash table manipulation */
+struct dmu_map *ht_find_map(struct hash_table *ht, uint64_t block);
+void ht_insert_map(struct hash_table *ht, struct dmu_map *map);
+struct dmu_map *ht_find_map_dev(struct dmu_device *dev, uint64_t block);
+void ht_delete_map(struct hash_table *ht, struct dmu_map *map);
+
+/* Character device transport functions */
+int register_chardev_transport(struct dmu_device *dev);
+void unregister_chardev_transport(struct dmu_device *dev);
+int init_chardev_transport(void);
+void cleanup_chardev_transport(void);
+void write_chardev_transport_info(struct dmu_device *dev,
+ char *buf, unsigned int maxlen);
+
+/* Return the block number for @sector */
+static inline u64 dmu_block(struct dmu_device *dev,
+ sector_t sector)
+{
+ return sector >> dev->block_shift;
+}
+
+/* Return the sector offset in a block for @sector */
+static inline u64 dmu_sector_offset(struct dmu_device *dev,
+ sector_t sector)
+{
+ return sector & dev->block_mask;
+}
+
+/* Return the starting sector for @block */
+static inline u64 dmu_sector(struct dmu_device *dev,
+ uint64_t block)
+{
+ return block << dev->block_shift;
+}
+
+/* Add a request to a device's request queue */
+static void add_request(struct dmu_device *dev,
+ struct userspace_request *req)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&dev->lock, flags);
+ list_add_tail(&req->list, &dev->requests);
+ spin_unlock_irqrestore(&dev->lock, flags);
+
+ wake_up(&dev->wqueue);
+}
+
+/* Remap @bio based on the information in @remap */
+static void __bio_remap(struct bio *bio,
+ struct dmu_map *remap)
+{
+ BUG_ON(remap->dest == NULL);
+
+ bio->bi_sector = dmu_sector(remap->dev, remap->new_block) +
+ dmu_sector_offset(remap->dev, bio->bi_sector) +
+ remap->offset;
+
+ bio->bi_bdev = remap->dest->bdev;
+}
+
+/* Increase the usage count for @dev */
+static inline void get_dev(struct dmu_device *dev)
+{
+ kref_get(&dev->users);
+}
+
+/* Decrease the usage count for @dev */
+void destroy_dmu_device(struct kref *ref);
+static inline void put_dev(struct dmu_device *dev)
+{
+ kref_put(&dev->users, destroy_dmu_device);
+}
+
+#endif
diff -Naur linux-2.6.17.6-orig/drivers/md/dm-userspace.c linux-2.6.17.6-dmu/drivers/md/dm-userspace.c
--- linux-2.6.17.6-orig/drivers/md/dm-userspace.c 1969-12-31 16:00:00.000000000 -0800
+++ linux-2.6.17.6-dmu/drivers/md/dm-userspace.c 2006-07-27 14:32:05.000000000 -0700
@@ -0,0 +1,1090 @@
+/*
+ * Copyright (C) International Business Machines Corp., 2006
+ * Author: Dan Smith <danms@...ibm.com>
+ *
+ * This program 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; under version 2 of the License.
+ *
+ * This program 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 this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/blkdev.h>
+#include <linux/bio.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/list.h>
+#include <linux/fs.h>
+#include <linux/cdev.h>
+#include <linux/types.h>
+#include <linux/poll.h>
+
+#include <linux/dm-userspace.h>
+
+#include "dm.h"
+#include "dm-bio-list.h"
+#include "kcopyd.h"
+#include "dm-user.h"
+
+#define DMU_COPY_PAGES 256
+#define DMU_REMAP_RESERVE 128
+
+#define DM_MSG_PREFIX "dm-userspace"
+
+static kmem_cache_t *request_cache;
+static kmem_cache_t *remap_cache;
+
+mempool_t *request_pool;
+
+static int enable_watchdog = 0;
+static struct work_struct wd;
+
+spinlock_t devices_lock;
+LIST_HEAD(devices);
+
+static spinlock_t mru_list_lock;
+static LIST_HEAD(mru_list);
+
+/* Device number for the control device */
+dev_t dmu_dev;
+
+static int error_bios(struct bio_list *bios)
+{
+ struct bio *bio;
+ int count = 0;
+
+ while ((bio = bio_list_pop(bios)) != NULL) {
+ bio_io_error(bio, bio->bi_size);
+ count++;
+ }
+
+ if (count)
+ DMERR("*** Failed %i requests", count);
+
+ return count;
+}
+
+static void remap_hit(struct dmu_map *remap)
+{
+ spin_lock(&mru_list_lock);
+
+ list_del_init(&remap->mru_list);
+ list_add(&remap->mru_list, &mru_list);
+
+ spin_unlock(&mru_list_lock);
+}
+
+struct dmu_map *alloc_remap_atomic(struct dmu_device *dev)
+{
+ struct dmu_map *remap = NULL;
+
+ /* Try to allocate one from the cache */
+ remap = kmem_cache_alloc(remap_cache, GFP_NOIO);
+ if (remap) {
+
+ INIT_LIST_HEAD(&remap->mru_list);
+
+ spin_lock(&mru_list_lock);
+ list_add_tail(&remap->mru_list, &mru_list);
+ spin_unlock(&mru_list_lock);
+
+ goto out;
+ }
+
+ /* Unable to alloc one, so get the LRU item off the list */
+ spin_lock(&mru_list_lock);
+ remap = list_entry(mru_list.prev, struct dmu_map, mru_list);
+ spin_unlock(&mru_list_lock);
+
+ if (remap) {
+ struct dmu_device *dev = remap->dev;
+ unsigned long flags;
+
+ DMINFO("Memory is low. Stealing the LRU remap...");
+
+ spin_lock_irqsave(&dev->lock, flags);
+ spin_lock(&remap->lock);
+ if (dmu_get_flag(&remap->flags, DMU_FLAG_INUSE)) {
+ /* Remove it from whatever device owns it */
+
+ if (!list_empty(&remap->list))
+ list_del_init(&remap->list);
+
+ remap->flags &= (~DMU_FLAG_INUSE);
+
+ if (!dmu_get_flag(&remap->flags, DMU_FLAG_VALID)) {
+ /* If the LRU remap is not valid,
+ we're in trouble */
+ spin_unlock(&remap->lock);
+ spin_unlock_irqrestore(&dev->lock, flags);
+ printk(KERN_EMERG
+ "dm-userspace: Unable to allocate "
+ "or steal a remap!\n");
+ goto out;
+ }
+ }
+
+ spin_unlock(&remap->lock);
+ spin_unlock_irqrestore(&dev->lock, flags);
+
+ remap_hit(remap);
+ }
+
+ out:
+ return remap;
+}
+
+void free_remap(struct dmu_map *remap)
+{
+ unsigned long flags;
+
+ if (error_bios(&remap->bios))
+ DMERR("Freed a map with in-flight data!");
+
+ spin_lock_irqsave(&remap->lock, flags);
+ remap->flags &= (~DMU_FLAG_INUSE);
+ spin_unlock_irqrestore(&remap->lock, flags);
+
+ spin_lock(&mru_list_lock);
+ list_del_init(&remap->mru_list);
+ list_add_tail(&remap->mru_list, &mru_list);
+ spin_unlock(&mru_list_lock);
+}
+
+void __free_remap(struct dmu_map *remap)
+{
+ if (error_bios(&remap->bios))
+ DMERR("Freed a map with in-flight data!");
+
+ remap->flags &= (~DMU_FLAG_INUSE);
+
+ spin_lock(&mru_list_lock);
+ list_del_init(&remap->mru_list);
+ list_add_tail(&remap->mru_list, &mru_list);
+ spin_unlock(&mru_list_lock);
+}
+
+void init_remap(struct dmu_device *dev, struct dmu_map *remap)
+{
+ spin_lock_init(&remap->lock);
+ remap->org_block = remap->new_block = 0;
+ remap->offset = 0;
+ remap->flags = DMU_FLAG_INUSE;
+ remap->src = remap->dest = NULL;
+ bio_list_init(&remap->bios);
+ bio_list_init(&remap->bios_waiting);
+ INIT_LIST_HEAD(&remap->list);
+ INIT_LIST_HEAD(&remap->in_flight);
+ remap->dev = dev;
+ remap->next = NULL;
+}
+
+void init_request(struct dmu_device *dev,
+ int type,
+ struct userspace_request *req)
+{
+ spin_lock_init(&req->lock);
+ INIT_LIST_HEAD(&req->list);
+ req->dev = dev;
+ req->type = type;
+ req->sent = 0;
+ req->flags = 0;
+ if (type == DM_USERSPACE_SYNC_COMPLETE) {
+ req->u.block = 0;
+ req->id = 0;
+ } else {
+ unsigned long flags;
+
+ bio_list_init(&req->u.bios);
+ spin_lock_irqsave(&dev->lock, flags);
+ dev->id_counter++;
+ if (dev->id_counter == 0)
+ dev->id_counter = 1;
+ req->id = dev->id_counter;
+ spin_unlock_irqrestore(&dev->lock, flags);
+ }
+ atomic_set(&req->refcnt, 0);
+}
+
+/*
+ * For an even block distribution, this is not too bad, but it could
+ * probably be better
+ */
+static uint32_t ht_hash(struct hash_table *ht, uint64_t block)
+{
+ return (uint32_t)block & ht->mask;
+}
+
+static int ht_init(struct hash_table *ht, unsigned long size)
+{
+ uint64_t i;
+ unsigned long pages;
+ unsigned int order = ffs((size * sizeof(struct list_head *)) /
+ PAGE_SIZE);
+
+ pages = __get_free_pages(GFP_ATOMIC, order);
+ if (!pages)
+ return 0;
+
+ ht->table = (void *)pages;
+ ht->size = size;
+ ht->count = 0;
+ ht->mask = size - 1;
+
+ for (i = 0; i < size; i++)
+ INIT_LIST_HEAD(&ht->table[i]);
+
+ return 1;
+}
+
+static void ht_insert_bucket(struct dmu_map *map, struct list_head *list)
+{
+ list_add_tail(&map->list, list);
+}
+
+/*
+ * I'm sure this is quite dumb, but it works for now
+ */
+static int ht_should_grow(struct hash_table *ht)
+{
+ return ht->count > (2 * (ht->size / 4));
+}
+
+static void ht_grow_table(struct hash_table *ht);
+void ht_insert_map(struct hash_table *ht, struct dmu_map *map)
+{
+ uint32_t addr;
+
+ addr = ht_hash(ht, map->org_block) & ht->mask;
+
+ BUG_ON(addr >= ht->size);
+
+ ht_insert_bucket(map, &ht->table[addr]);
+ ht->count++;
+
+ if (ht_should_grow(ht))
+ ht_grow_table(ht);
+}
+
+void ht_delete_map(struct hash_table *ht, struct dmu_map *map)
+{
+ list_del_init(&map->list);
+ BUG_ON(ht->count == 0);
+ ht->count--;
+}
+
+struct dmu_map *ht_find_map(struct hash_table *ht, uint64_t block)
+{
+ uint32_t addr;
+ struct dmu_map *m;
+
+ addr = ht_hash(ht, block) & ht->mask;
+
+ BUG_ON(addr >= ht->size);
+
+ list_for_each_entry(m, &ht->table[addr], list) {
+ if (m->org_block == block) {
+ remap_hit(m);
+ return m;
+ }
+ }
+
+ return NULL;
+}
+
+struct dmu_map *ht_find_map_dev(struct dmu_device *dev, uint64_t block)
+{
+ struct dmu_map *remap;
+ unsigned long flags;
+
+ spin_lock_irqsave(&dev->lock, flags);
+
+ remap = ht_find_map(&dev->remaps, block);
+
+ spin_unlock_irqrestore(&dev->lock, flags);
+
+ return remap;
+}
+
+static void ht_grow_table(struct hash_table *ht)
+{
+ struct hash_table old_table;
+ uint64_t i;
+
+ old_table = *ht;
+
+ if (!ht_init(ht, old_table.size * 2))
+ return;
+
+ for (i = 0; i < old_table.size; i++ ) {
+ struct dmu_map *m, *n;
+ list_for_each_entry_safe(m, n, &old_table.table[i],
+ list) {
+ list_del_init(&m->list);
+ ht_insert_map(ht, m);
+ }
+ }
+
+ free_pages((unsigned long)old_table.table,
+ ffs((old_table.size * sizeof(struct list_head *))
+ / PAGE_SIZE));
+}
+
+static uint64_t ht_destroy_table(struct hash_table *ht)
+{
+ uint64_t i, count = 0;
+ struct dmu_map *m, *n;
+
+ for (i = 0; i < ht->size; i++) {
+ list_for_each_entry_safe(m, n, &ht->table[i], list) {
+ ht_delete_map(ht, m);
+ free_remap(m);
+ count++;
+ }
+ }
+
+ return count;
+}
+
+struct target_device *find_target(struct dmu_device *dev,
+ dev_t devno)
+{
+ struct target_device *target, *match = NULL;
+ unsigned long flags;
+
+ spin_lock_irqsave(&dev->lock, flags);
+ list_for_each_entry(target, &dev->target_devs, list) {
+ if (target->bdev->bd_dev == devno) {
+ match = target;
+ break;
+ }
+ }
+ spin_unlock_irqrestore(&dev->lock, flags);
+
+ return match;
+}
+
+static struct target_device *get_target(struct dmu_device *dev,
+ dev_t devno)
+{
+
+ struct target_device *target;
+ struct block_device *bdev;
+ unsigned long flags;
+
+ target = find_target(dev, devno);
+ if (target)
+ return target;
+
+ bdev = open_by_devnum(devno, FMODE_READ | FMODE_WRITE);
+ if (IS_ERR(bdev)) {
+ DMERR("Unable to lookup device %x", devno);
+ return NULL;
+ }
+
+ target = kmalloc(sizeof(*target), GFP_KERNEL);
+ if (!target) {
+ DMERR("Unable to alloc new target device");
+ return NULL;
+ }
+
+ target->bdev = bdev;
+ INIT_LIST_HEAD(&target->list);
+
+ spin_lock_irqsave(&dev->lock, flags);
+ list_add_tail(&target->list, &dev->target_devs);
+ spin_unlock_irqrestore(&dev->lock, flags);
+
+ return target;
+}
+
+/* Caller must hold dev->lock */
+static void put_target(struct dmu_device *dev,
+ struct target_device *target)
+{
+ list_del(&target->list);
+
+ bd_release(target->bdev);
+ blkdev_put(target->bdev);
+
+ kfree(target);
+}
+
+/*
+ * This periodically dumps out some debug information. It's really
+ * only useful while developing.
+ */
+static void watchdog(void *data)
+{
+ unsigned int v_remaps, i_remaps, reqs, s_reqs, devs = 0;
+ struct dmu_device *dev;
+ struct dmu_map *map;
+ struct userspace_request *req;
+ uint64_t i;
+
+ spin_lock(&devices_lock);
+
+ list_for_each_entry(dev, &devices, list) {
+ unsigned long flags;
+
+ spin_lock_irqsave(&dev->lock, flags);
+
+ v_remaps = i_remaps = reqs = s_reqs = 0;
+
+ for (i = 0; i < dev->remaps.size; i++) {
+ list_for_each_entry(map, &dev->remaps.table[i], list)
+ if (dmu_get_flag(&map->flags, DMU_FLAG_VALID))
+ v_remaps++;
+ else
+ i_remaps++;
+ }
+
+ list_for_each_entry(req, &dev->requests, list)
+ if (req->sent)
+ s_reqs++;
+ else
+ reqs++;
+
+ printk("Device "
+ " reqs: %u/%u "
+ " inv maps: %u "
+ " val maps: %u\n",
+ reqs, s_reqs, i_remaps, v_remaps);
+ devs++;
+
+ spin_unlock_irqrestore(&dev->lock, flags);
+ }
+
+ spin_unlock(&devices_lock);
+
+ schedule_delayed_work(&wd, HZ);
+}
+
+void destroy_dmu_device(struct kref *ref)
+{
+ struct dmu_device *dev;
+ struct list_head *cursor, *next;
+ uint64_t remaps;
+
+ dev = container_of(ref, struct dmu_device, users);
+
+ spin_lock(&devices_lock);
+ list_del(&dev->list);
+ spin_unlock(&devices_lock);
+
+ list_for_each_safe(cursor, next, &dev->target_devs) {
+ struct target_device *target;
+
+ target = list_entry(cursor,
+ struct target_device,
+ list);
+
+ put_target(dev, target);
+ }
+
+ remaps = ht_destroy_table(&dev->remaps);
+
+ list_for_each_safe(cursor, next, &dev->requests) {
+ struct userspace_request *req;
+
+ req = list_entry(cursor,
+ struct userspace_request,
+ list);
+
+ list_del(&req->list);
+
+ error_bios(&req->u.bios);
+
+ mempool_free(req, request_pool);
+ }
+
+ kcopyd_client_destroy(dev->kcopy);
+ unregister_chardev_transport(dev);
+
+ kfree(dev);
+}
+
+static int init_dmu_device(struct dmu_device *dev, u32 block_size)
+{
+ int ret;
+
+ init_waitqueue_head(&dev->wqueue);
+ INIT_LIST_HEAD(&dev->list);
+ INIT_LIST_HEAD(&dev->requests);
+ INIT_LIST_HEAD(&dev->target_devs);
+ INIT_LIST_HEAD(&dev->in_flight);
+ kref_init(&dev->users);
+ spin_lock_init(&dev->lock);
+
+ dev->id_counter = 1; /* reserve 0 for unsolicited maps */
+
+ if (!ht_init(&dev->remaps, 2048)) {
+ DMERR("Unable to allocate hash table");
+ return 0;
+ }
+
+ dev->block_size = block_size;
+ dev->block_mask = block_size - 1;
+ dev->block_shift = ffs(block_size) - 1;
+
+ ret = kcopyd_client_create(DMU_COPY_PAGES, &dev->kcopy);
+ if (ret) {
+ DMERR("Failed to initialize kcopyd client");
+ return 0;
+ }
+
+ return 1;
+}
+
+static struct dmu_device *new_dmu_device(char *key,
+ struct dm_target *ti,
+ u32 block_size)
+{
+ struct dmu_device *dev;
+ int ret;
+
+ dev = kmalloc(sizeof(*dev), GFP_KERNEL);
+ if (dev == NULL) {
+ DMERR("Failed to allocate new userspace device");
+ return NULL;
+ }
+
+ if (!init_dmu_device(dev, block_size))
+ goto bad1;
+
+ snprintf(dev->key, DMU_KEY_LEN, "%s", key);
+
+ ret = register_chardev_transport(dev);
+ if (!ret)
+ goto bad2;
+
+ spin_lock(&devices_lock);
+ list_add(&dev->list, &devices);
+ spin_unlock(&devices_lock);
+
+ return dev;
+
+ bad2:
+ put_dev(dev);
+ bad1:
+ kfree(dev);
+ DMERR("Failed to create device");
+ return NULL;
+}
+
+static struct dmu_device *find_dmu_device(const char *key)
+{
+ struct dmu_device *dev;
+ struct dmu_device *match = NULL;
+
+ spin_lock(&devices_lock);
+
+ list_for_each_entry(dev, &devices, list) {
+ unsigned long flags;
+
+ spin_lock_irqsave(&dev->lock, flags);
+ if (strncmp(dev->key, key, DMU_KEY_LEN) == 0) {
+ match = dev;
+ spin_unlock(&dev->lock);
+ break;
+ }
+ spin_unlock_irqrestore(&dev->lock, flags);
+ }
+
+ spin_unlock(&devices_lock);
+
+ return match;
+}
+
+static int dmu_ctr(struct dm_target *ti, unsigned int argc, char **argv)
+{
+ uint64_t block_size;
+ struct dmu_device *dev;
+ char *device_key;
+ char *block_size_param;
+ int target_idx = 2;
+ unsigned long flags;
+
+ if (argc < 3) {
+ ti->error = "Invalid argument count";
+ return -EINVAL;
+ }
+
+ device_key = argv[0];
+ block_size_param = argv[1];
+
+ block_size = simple_strtoul(block_size_param, NULL, 10) / 512;
+
+ dev = find_dmu_device(device_key);
+ if (dev == NULL) {
+ dev = new_dmu_device(device_key,
+ ti,
+ block_size);
+ if (dev == NULL) {
+ ti->error = "Failed to create device";
+ goto bad;
+ }
+ } else {
+ get_dev(dev);
+ }
+
+ spin_lock_irqsave(&dev->lock, flags);
+ if (dev->block_size != block_size) {
+ ti->error = "Invalid block size";
+ goto bad;
+ }
+ spin_unlock_irqrestore(&dev->lock, flags);
+
+ /* Resolve target devices */
+ do {
+ int maj, min;
+ sscanf(argv[target_idx], "%i:%i", &maj, &min);
+ if (!get_target(dev, MKDEV(maj, min))) {
+ DMERR("Failed to find target device %i:%i (%s)",
+ maj, min, argv[target_idx]);
+ goto out;
+ }
+ } while (++target_idx < argc);
+
+ ti->private = dev;
+ ti->split_io = block_size;
+
+ return 0;
+
+ bad:
+ if (dev) {
+ spin_unlock_irqrestore(&dev->lock, flags);
+ }
+ out:
+ if (dev) {
+ put_dev(dev);
+ }
+
+ return -EINVAL;
+}
+
+static void dmu_dtr(struct dm_target *ti)
+{
+ struct dmu_device *dev = (struct dmu_device *) ti->private;
+
+ put_dev(dev);
+}
+
+/* Search @dev for an outstanding request for remapping @block */
+static struct userspace_request *find_existing_req(struct dmu_device *dev,
+ uint64_t block)
+{
+ struct userspace_request *req;
+ struct userspace_request *maybe = NULL;
+ unsigned long flags;
+
+ spin_lock_irqsave(&dev->lock, flags);
+
+ list_for_each_entry(req, &dev->requests, list) {
+ if ((req->type == DM_USERSPACE_MAP_BLOCK_REQ) &&
+ (dmu_block(dev, req->u.bios.head->bi_sector) == block)) {
+ if (maybe) {
+ atomic_dec(&maybe->refcnt);
+ }
+ maybe = req;
+ atomic_inc(&maybe->refcnt);
+ }
+ }
+
+ spin_unlock_irqrestore(&dev->lock, flags);
+
+ return maybe;
+}
+
+static int make_new_request(struct dmu_device *dev, struct bio *bio)
+{
+ struct userspace_request *req;
+
+ req = mempool_alloc(request_pool, GFP_NOIO);
+ if (req == NULL)
+ goto bad;
+
+ init_request(dev, DM_USERSPACE_MAP_BLOCK_REQ, req);
+
+ dmu_set_flag(&req->flags, DMU_FLAG_RD);
+ if (bio_rw(bio))
+ dmu_set_flag(&req->flags, DMU_FLAG_WR);
+ else
+ dmu_clr_flag(&req->flags, DMU_FLAG_WR);
+ bio_list_add(&req->u.bios, bio);
+
+ add_request(dev, req);
+
+ return 0;
+
+ bad:
+ DMERR("Failed to queue bio!");
+ return -1;
+}
+
+static int dmu_map_remap_case(struct dmu_device *dev,
+ struct dmu_map *remap,
+ struct bio *bio)
+{
+ int ret = 0;
+ int rw;
+ unsigned long flags;
+
+ spin_lock_irqsave(&remap->lock, flags);
+
+ /*
+ * We've got it locked, so make sure the info is still valid
+ * before we use it
+ */
+ if (!dmu_get_flag(&remap->flags, DMU_FLAG_INUSE)) {
+ ret = -1;
+ goto unlock;
+ } else if (remap->org_block != dmu_block(dev, bio->bi_sector)) {
+ ret = -1;
+ goto unlock;
+ }
+
+ rw = dmu_get_flag(&remap->flags, DMU_FLAG_WR);
+
+ if (bio_rw(bio) && !rw) {
+ ret = -1;
+ } else {
+ if (dmu_get_flag(&remap->flags, DMU_FLAG_VALID)) {
+ __bio_remap(bio, remap);
+ ret = 1;
+ } else {
+ bio_list_add(&remap->bios, bio);
+ }
+ }
+
+ unlock:
+ spin_unlock_irqrestore(&remap->lock, flags);
+
+ return ret;
+}
+
+static int dmu_map_request_case(struct dmu_device *dev,
+ struct userspace_request *req,
+ struct bio *bio)
+{
+ int ret = 0;
+ int req_rw = dmu_get_flag(&req->flags, DMU_FLAG_WR);
+
+ spin_lock(&req->lock);
+
+ if (!req_rw && bio_rw(bio) && !req->sent) {
+ /* Convert to R/W and Queue */
+ dmu_set_flag(&req->flags, DMU_FLAG_WR);
+ bio_list_add(&req->u.bios, bio);
+ } else if (!req_rw && bio_rw(bio) && req->sent) {
+ /* Can't convert, must re-request */
+ ret = -1;
+ } else {
+ /* Queue */
+ bio_list_add(&req->u.bios, bio);
+ }
+
+ spin_unlock(&req->lock);
+
+ return ret;
+}
+
+static int dmu_map(struct dm_target *ti, struct bio *bio,
+ union map_info *map_context)
+{
+ struct dmu_device *dev = (struct dmu_device *) ti->private;
+ struct dmu_map *remap;
+ struct userspace_request *req;
+ int ret = 0;
+ u64 block;
+
+ block = dmu_block(dev, bio->bi_sector);
+
+ remap = ht_find_map_dev(dev, block);
+ if (remap) {
+ ret = dmu_map_remap_case(dev, remap, bio);
+ if (ret >= 0)
+ goto done;
+ }
+
+ req = find_existing_req(dev, block);
+ if (req) {
+ ret = dmu_map_request_case(dev, req, bio);
+ atomic_dec(&req->refcnt);
+ if (ret >= 0)
+ goto done;
+ }
+
+ ret = make_new_request(dev, bio);
+
+ done:
+ return ret;
+}
+
+static int dmu_status(struct dm_target *ti, status_type_t type,
+ char *result, unsigned int maxlen)
+{
+ struct dmu_device *dev = (struct dmu_device *) ti->private;
+
+ switch (type) {
+ case STATUSTYPE_INFO:
+ write_chardev_transport_info(dev, result, maxlen);
+ break;
+
+ case STATUSTYPE_TABLE:
+ snprintf(result, maxlen, "%s %llu",
+ dev->key,
+ dev->block_size * 512);
+ break;
+ }
+
+ return 0;
+}
+
+static struct userspace_request *make_sync_req(struct dmu_device
+ *dev,
+ uint32_t id)
+{
+ struct userspace_request *req;
+ req = mempool_alloc(request_pool, GFP_ATOMIC);
+ if (!req) {
+ printk(KERN_ERR "Failed to allocate copy response\n");
+ return NULL;
+ }
+ init_request(dev, DM_USERSPACE_SYNC_COMPLETE, req);
+ req->id = id;
+
+ return req;
+}
+
+static int __handle_bio_endio(struct dmu_map *remap,
+ struct bio *bio,
+ struct userspace_request **req)
+{
+ int ret = 0;
+
+ spin_lock(&remap->lock); /* IRQs already disabled */
+ if (dmu_get_flag(&remap->flags, DMU_FLAG_WAITING) &&
+ remap->bios_waiting.head == NULL) {
+ /* First endio and waiting for resp from userspace */
+ bio_list_add(&remap->bios_waiting, bio);
+ *req = make_sync_req(remap->dev, remap->id);
+ if (*req)
+ ret = 1;
+ else
+ ret = 0; /* Failed to alloc, allow retry */
+ } else if (dmu_get_flag(&remap->flags,
+ DMU_FLAG_WAITING)) {
+ /* Still waiting for resp from userspace */
+ bio_list_add(&remap->bios_waiting, bio);
+ ret = 1;
+ } else if (remap->bios_waiting.head != NULL) {
+ /* Got resp from userspace but bios waiting list nonempty */
+ if (bio->bi_sector == remap->bios_waiting.head->bi_sector) {
+ bio_list_pop(&remap->bios_waiting);
+ ret = 0;
+ } else {
+ bio_list_add(&remap->bios_waiting, bio);
+ ret = 1;
+ }
+ } else {
+ /* no waiting, list empty, remove from remap */
+ list_del(&remap->in_flight);
+ ret = 0;
+ }
+ spin_unlock(&remap->lock);
+
+ return ret;
+}
+
+static int dmu_end_io(struct dm_target *ti, struct bio *bio,
+ int error, union map_info *map_context)
+{
+ struct dmu_device *dev = (struct dmu_device *) ti->private;
+ struct dmu_map *p;
+ struct userspace_request *req = NULL;
+ u64 block;
+ int ret = 0;
+ unsigned long flags;
+
+ if (error) {
+ DMERR("Error in dmu_end_io\n");
+ return -1;
+ }
+
+ block = dmu_block(dev, bio->bi_sector);
+
+ spin_lock_irqsave(&dev->lock, flags);
+ list_for_each_entry(p, &dev->in_flight, in_flight) {
+ if (p->new_block == block) {
+ ret = __handle_bio_endio(p, bio, &req);
+ break;
+ }
+ }
+ spin_unlock_irqrestore(&dev->lock, flags);
+
+ if (req)
+ add_request(dev, req);
+
+ return ret;
+}
+
+struct target_type userspace_target = {
+ .name = "userspace",
+ .version = {0, 1, 0},
+ .module = THIS_MODULE,
+ .ctr = dmu_ctr,
+ .dtr = dmu_dtr,
+ .map = dmu_map,
+ .status = dmu_status,
+ .end_io = dmu_end_io
+};
+
+static int destroy_mru_list(void)
+{
+ struct dmu_map *map, *next;
+ int count = 0;
+
+ spin_lock(&mru_list_lock);
+
+ list_for_each_entry_safe(map, next, &mru_list, mru_list) {
+ list_del(&map->mru_list);
+ kmem_cache_free(remap_cache, map);
+ count++;
+ }
+
+ spin_unlock(&mru_list_lock);
+
+ return count;
+}
+
+int __init dm_userspace_init(void)
+{
+ int i;
+ int r = dm_register_target(&userspace_target);
+ if (r < 0) {
+ DMERR("Register failed %d", r);
+ return 0;
+ }
+
+ spin_lock_init(&devices_lock);
+ spin_lock_init(&mru_list_lock);
+
+ if (enable_watchdog) {
+ INIT_WORK(&wd, watchdog, NULL);
+ schedule_delayed_work(&wd, HZ);
+ }
+
+ request_cache =
+ kmem_cache_create("dm-userspace-requests",
+ sizeof(struct userspace_request),
+ __alignof__ (struct userspace_request),
+ 0, NULL, NULL);
+ if (!request_cache) {
+ DMERR("Failed to allocate request cache");
+ goto bad;
+ }
+
+ remap_cache =
+ kmem_cache_create("dm-userspace-remaps",
+ sizeof(struct dmu_map),
+ __alignof__ (struct dmu_map),
+ 0, NULL, NULL);
+ if (!remap_cache) {
+ DMERR("Failed to allocate remap cache");
+ goto bad2;
+ }
+
+ request_pool = mempool_create(64,
+ mempool_alloc_slab, mempool_free_slab,
+ request_cache);
+ if (!request_pool) {
+ DMERR("Failed to allocate request pool");
+ goto bad3;
+ }
+
+ r = init_chardev_transport();
+ if (!r)
+ goto bad4;
+
+ for (i = 0; i < DMU_REMAP_RESERVE; i++) {
+ struct dmu_map *remap;
+
+ remap = alloc_remap_atomic(NULL);
+ if (!remap) {
+ DMERR("Failed to allocate %i/%i reserve remap",
+ i, DMU_REMAP_RESERVE);
+ goto bad5;
+ }
+ init_remap(NULL, remap);
+ remap_hit(remap);
+ }
+
+ return 1;
+
+ bad5:
+ destroy_mru_list();
+ bad4:
+ mempool_destroy(request_pool);
+ bad3:
+ kmem_cache_destroy(remap_cache);
+ bad2:
+ kmem_cache_destroy(request_cache);
+ bad:
+ dm_unregister_target(&userspace_target);
+
+ return 0;
+}
+
+void __exit dm_userspace_exit(void)
+{
+ int r;
+ struct list_head *cursor, *next;
+ struct dmu_device *dev;
+
+ if (enable_watchdog)
+ if (!cancel_delayed_work(&wd))
+ flush_scheduled_work();
+
+ spin_lock(&devices_lock);
+
+ list_for_each_safe(cursor, next, &devices) {
+ dev = list_entry(cursor, struct dmu_device, list);
+ list_del(cursor);
+ destroy_dmu_device(&dev->users);
+ DMERR("Destroying hanging device %s", dev->key);
+ }
+
+ spin_unlock(&devices_lock);
+
+ cleanup_chardev_transport();
+
+ r = destroy_mru_list();
+
+ mempool_destroy(request_pool);
+ kmem_cache_destroy(request_cache);
+ kmem_cache_destroy(remap_cache);
+
+ r = dm_unregister_target(&userspace_target);
+ if (r < 0)
+ DMERR("unregister failed %d", r);
+}
+
+module_init(dm_userspace_init);
+module_exit(dm_userspace_exit);
+
+module_param(enable_watchdog, int, S_IRUGO);
+
+MODULE_DESCRIPTION(DM_NAME " userspace target");
+MODULE_AUTHOR("Dan Smith");
+MODULE_LICENSE("GPL");
diff -Naur linux-2.6.17.6-orig/drivers/md/dm-userspace-chardev.c linux-2.6.17.6-dmu/drivers/md/dm-userspace-chardev.c
--- linux-2.6.17.6-orig/drivers/md/dm-userspace-chardev.c 1969-12-31 16:00:00.000000000 -0800
+++ linux-2.6.17.6-dmu/drivers/md/dm-userspace-chardev.c 2006-07-27 14:32:05.000000000 -0700
@@ -0,0 +1,856 @@
+/*
+ * Copyright (C) International Business Machines Corp., 2006
+ * Author: Dan Smith <danms@...ibm.com>
+ *
+ * This program 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; under version 2 of the License.
+ *
+ * This program 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 this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ *
+ */
+
+#include <linux/spinlock.h>
+#include <linux/blkdev.h>
+#include <linux/mempool.h>
+#include <linux/dm-userspace.h>
+#include <linux/list.h>
+#include <linux/sched.h>
+#include <linux/wait.h>
+#include <linux/poll.h>
+#include <linux/fs.h>
+#include <linux/cdev.h>
+#include <asm/uaccess.h>
+
+#include "dm.h"
+#include "dm-bio-list.h"
+#include "kcopyd.h"
+#include "dm-user.h"
+
+#define DM_MSG_PREFIX "dm-userspace"
+
+/* This allows for a cleaner separation between the dm-userspace
+ * device-mapper target, and the userspace transport used. Right now,
+ * only a chardev transport exists, but it's possible that there could
+ * be more in the future
+ */
+struct chardev_transport {
+ struct cdev cdev;
+ dev_t ctl_dev;
+ struct dmu_device *parent;
+};
+
+static void remap_flusher(struct dmu_map *remap);
+
+static int have_pending_requests(struct dmu_device *dev)
+{
+ struct userspace_request *req;
+ int ret = 0;
+ unsigned long flags;
+
+ /* FIXME: We should keep a count of how many waiting reqs
+ * there are, eliminating the need to count, and possibly the
+ * need to lock
+ */
+
+ spin_lock_irqsave(&dev->lock, flags);
+
+ list_for_each_entry(req, &dev->requests, list) {
+ if (!req->sent) {
+ ret = 1;
+ break;
+ }
+ }
+
+ spin_unlock_irqrestore(&dev->lock, flags);
+
+ return ret;
+}
+
+static void copy_callback(int read_err,
+ unsigned int write_err,
+ void *data)
+{
+ remap_flusher((struct dmu_map *)data);
+}
+
+static void copy_block(struct dmu_map *remap)
+{
+ struct io_region src, dst;
+ struct kcopyd_client *client;
+ unsigned long flags;
+
+ spin_lock_irqsave(&remap->lock, flags);
+
+ src.bdev = remap->src->bdev;
+ src.sector = remap->org_block << remap->dev->block_shift;
+ src.count = remap->dev->block_size;
+
+ dst.bdev = remap->dest->bdev;
+ dst.sector = (remap->new_block << remap->dev->block_shift);
+ dst.sector += remap->offset;
+ dst.count = remap->dev->block_size;
+
+ client = remap->dev->kcopy;
+
+ spin_unlock_irqrestore(&remap->lock, flags);
+
+ kcopyd_copy(client, &src, 1, &dst, 0, copy_callback, remap);
+}
+
+static void copy_or_flush(struct dmu_map *remap)
+{
+ int copy;
+ unsigned long flags;
+
+ spin_lock_irqsave(&remap->lock, flags);
+ copy = dmu_get_flag(&remap->flags, DMU_FLAG_COPY_FIRST);
+ spin_unlock_irqrestore(&remap->lock, flags);
+
+ if (copy)
+ copy_block(remap);
+ else
+ remap_flusher(remap);
+}
+
+static struct bio *pop_and_remap(struct dmu_map *remap)
+{
+ struct bio *bio = NULL;
+ unsigned long flags;
+
+ spin_lock_irqsave(&remap->lock, flags);
+
+ bio = bio_list_pop(&remap->bios);
+ if (bio)
+ __bio_remap(bio, remap);
+ else {
+ /* If there are no more bios, we must set the VALID
+ * flag before we release the lock
+ */
+ dmu_set_flag(&remap->flags, DMU_FLAG_VALID);
+ }
+
+ spin_unlock_irqrestore(&remap->lock, flags);
+
+ return bio;
+}
+
+static void get_remap_attrs(struct dmu_map *remap,
+ int *copy_first,
+ int *temporary,
+ struct dmu_map **next)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&remap->lock, flags);
+
+ *copy_first = dmu_get_flag(&remap->flags, DMU_FLAG_COPY_FIRST);
+ *temporary = dmu_get_flag(&remap->flags, DMU_FLAG_TEMPORARY);
+ *next = remap->next;
+ remap->next = NULL;
+
+ spin_unlock_irqrestore(&remap->lock, flags);
+}
+
+static void remap_flusher(struct dmu_map *remap)
+{
+ struct bio *bio;
+ int copy_first = 0, temporary = 0;
+ struct dmu_map *next;
+
+ while (1) {
+
+ bio = pop_and_remap(remap);
+
+ if (bio)
+ generic_make_request(bio);
+ else
+ break;
+ }
+
+ get_remap_attrs(remap, ©_first, &temporary, &next);
+
+ if (next)
+ copy_or_flush(next);
+
+ if (temporary)
+ free_remap(remap);
+}
+
+static int send_userspace_message(uint8_t __user *buffer,
+ struct userspace_request *req)
+{
+ int ret = 0;
+ struct dmu_msg_header hdr;
+ union {
+ struct dmu_msg_map_request map_req;
+ struct dmu_msg_status status_req;
+ struct dmu_msg_version ver_req;
+ } msgs;
+
+ spin_lock(&req->lock);
+
+ hdr.id = req->id;
+
+ switch (req->type) {
+ case DM_USERSPACE_GET_VERSION:
+ hdr.msg_type = req->type;
+ hdr.payload_len = sizeof(msgs.ver_req);
+ msgs.ver_req.kernel_ver =
+ userspace_target.version[0] << 16 |
+ userspace_target.version[1] << 8 |
+ userspace_target.version[2];
+
+ break;
+
+ case DM_USERSPACE_MAP_BLOCK_REQ:
+ hdr.msg_type = req->type;
+ hdr.payload_len = sizeof(msgs.map_req);
+ msgs.map_req.org_block =
+ dmu_block(req->dev, req->u.bios.head->bi_sector);
+ dmu_cpy_flag(&msgs.map_req.flags, req->flags, DMU_FLAG_RD);
+ dmu_cpy_flag(&msgs.map_req.flags, req->flags, DMU_FLAG_WR);
+
+ break;
+
+ case DM_USERSPACE_SYNC_COMPLETE:
+ case DM_USERSPACE_INVAL_COMPLETE:
+ case DM_USERSPACE_INVAL_FAILED:
+ hdr.msg_type = DM_USERSPACE_STATUS;
+ hdr.payload_len = sizeof(msgs.status_req);
+ msgs.status_req.status = req->type;
+ msgs.status_req.id_of_op = req->id;
+
+ break;
+
+ default:
+ DMWARN("Unknown message type %i", req->type);
+ ret = 0;
+ }
+
+ spin_unlock(&req->lock);
+
+ if (copy_to_user(buffer, &hdr, sizeof(hdr)))
+ return -EFAULT;
+ if (copy_to_user(buffer + sizeof(hdr), &msgs, hdr.payload_len))
+ return -EFAULT;
+
+ ret = sizeof(hdr) + hdr.payload_len;
+
+ if (req->type != DM_USERSPACE_MAP_BLOCK_REQ) {
+ unsigned long flags;
+ /* Only map requests get responses, so we take others
+ * off the request queue here
+ */
+ spin_lock_irqsave(&req->dev->lock, flags);
+ list_del(&req->list);
+ spin_unlock_irqrestore(&req->dev->lock, flags);
+ mempool_free(req, request_pool);
+ }
+
+ return ret;
+}
+
+struct userspace_request *pluck_next_request(struct dmu_device *dev,
+ int size_available)
+{
+ struct userspace_request *req, *match = NULL;
+ unsigned long flags;
+
+ spin_lock_irqsave(&dev->lock, flags);
+
+ list_for_each_entry(req, &dev->requests, list) {
+ spin_lock(&req->lock);
+ if (!req->sent) {
+ if (dmu_get_msg_len(req->type) < size_available) {
+ req->sent = 1;
+ match = req;
+ } else {
+ /* Must break here to preserve order */
+ spin_unlock(&req->lock);
+ break;
+ }
+ }
+ spin_unlock(&req->lock);
+
+ if (match)
+ break;
+ }
+
+ spin_unlock_irqrestore(&dev->lock, flags);
+
+ return match;
+}
+
+ssize_t dmu_ctl_read(struct file *file, char __user *buffer,
+ size_t size, loff_t *offset)
+{
+
+ struct dmu_device *dev = (struct dmu_device *)file->private_data;
+ struct userspace_request *req = NULL;
+ int ret = 0, r;
+
+ if (!capable(CAP_SYS_ADMIN))
+ return -EACCES;
+
+ while (!have_pending_requests(dev)) {
+ if (file->f_flags & O_NONBLOCK) {
+ return 0;
+ }
+
+ if (wait_event_interruptible(dev->wqueue,
+ have_pending_requests(dev)))
+ return -ERESTARTSYS;
+ }
+
+ while(ret < size) {
+ req = pluck_next_request(dev, size - ret);
+ if (!req)
+ /* One or more of the following conditions is true:
+ * 1. No more requests available for sending
+ * 2. No more room in the outgoing buffer
+ */
+ break;
+
+ r = send_userspace_message((void *)(buffer + ret), req);
+ if (r == 0)
+ continue;
+ else if (r < 0)
+ return r;
+
+ ret += r;
+ }
+
+ return ret;
+}
+
+static int remap_request(struct dmu_msg_map_response *msg,
+ struct dmu_device *dev, uint32_t id)
+{
+ struct dmu_map *remap = NULL, *parent = NULL;
+ struct target_device *s_dev = NULL, *d_dev = NULL;
+ int is_chained = 0;
+ struct bio_list bio_holder;
+ struct userspace_request *cursor, *next, *req = NULL;
+ unsigned long flags;
+
+ /* See if we have a pending request that matches */
+ spin_lock_irqsave(&dev->lock, flags);
+ list_for_each_entry_safe(cursor, next, &dev->requests, list) {
+ if ((cursor->type == DM_USERSPACE_MAP_BLOCK_REQ) &&
+ (cursor->id == msg->id_of_req)) {
+ req = cursor;
+ list_del(&req->list);
+ break;
+ }
+ }
+ spin_unlock_irqrestore(&dev->lock, flags);
+
+ if (dmu_get_flag(&msg->flags, DMU_FLAG_COPY_FIRST)) {
+ s_dev = find_target(dev, MKDEV(msg->src_maj, msg->src_min));
+ if (!s_dev) {
+ DMERR("Failed to find src device %i:%i",
+ msg->src_maj, msg->src_min);
+ goto bad;
+ }
+ }
+
+ d_dev = find_target(dev, MKDEV(msg->dst_maj, msg->dst_min));
+ if (!d_dev) {
+ DMERR("Failed to find dest device %i:%i",
+ msg->dst_maj, msg->dst_min);
+ goto bad;
+ }
+
+ if (req) {
+ while (atomic_read(&req->refcnt) != 0)
+ /* Wait for exclusive use of request. Even
+ * though we have removed it from the list,
+ * someone still has a pointer to it, which
+ * means we must wait for them to finish with
+ * it before continuing.
+ */
+ schedule();
+
+ bio_holder = req->u.bios;
+ mempool_free(req, request_pool);
+ } else {
+ bio_list_init(&bio_holder);
+ }
+
+ /* Allocate a new remap early (before grabbing locks), since
+ * we will most likely need it
+ */
+ remap = alloc_remap_atomic(dev);
+ if (!remap) {
+ DMERR("Failed to alloc remap!");
+ goto bad;
+ }
+
+ init_remap(dev, remap);
+
+ /* We don't need IRQ protection here, because we just created
+ * this
+ */
+ spin_lock(&remap->lock);
+ remap->org_block = msg->org_block;
+
+ spin_lock_irqsave(&dev->lock, flags);
+
+ /* Here, we insert the new remap into the table, and remove
+ * the existing map, if present, all in one locked operation
+ */
+
+ parent = ht_find_map(&dev->remaps, msg->org_block);
+ if (parent) {
+
+ spin_lock(&parent->lock); /* IRQs already disabled */
+
+ if (!dmu_get_flag(&parent->flags, DMU_FLAG_INUSE)) {
+ /* This is in the process of being destroyed,
+ * so we can't use it
+ */
+ goto end_parent;
+ }
+
+ if (!dmu_get_flag(&parent->flags, DMU_FLAG_VALID)) {
+ if (dmu_get_flag(&parent->flags, DMU_FLAG_WR) ==
+ dmu_get_flag(&msg->flags, DMU_FLAG_WR) &&
+ (parent->new_block == msg->new_block)) {
+ /* Perms match for this not-yet-valid remap,
+ so tag our bios on to it and bail */
+ bio_list_merge(&parent->bios,
+ &bio_holder);
+
+ spin_unlock(&parent->lock);
+ spin_unlock_irqrestore(&dev->lock, flags);
+ __free_remap(remap);
+ return 1;
+ } else {
+ /* Remove parent from remap table, and
+ * chain our new remap to this one so
+ * it will fire when parent goes
+ * valid
+ */
+ list_del_init(&parent->list);
+ if (parent->next) {
+ DMERR("Parent already chained!");
+ BUG();
+ }
+ parent->next = remap;
+ dmu_set_flag(&parent->flags,
+ DMU_FLAG_TEMPORARY);
+ is_chained = 1;
+ }
+ } else {
+ /* Remove existing valid remap */
+ __free_remap(parent);
+ }
+
+ end_parent:
+ spin_unlock(&parent->lock);
+ }
+
+ ht_insert_map(&dev->remaps, remap);
+
+ if (dmu_get_flag(&msg->flags, DMU_FLAG_SYNC)) {
+ list_add_tail(&remap->in_flight, &dev->in_flight);
+ dmu_set_flag(&remap->flags, DMU_FLAG_WAITING);
+ }
+
+ remap->new_block = msg->new_block;
+ remap->offset = msg->offset;
+ remap->src = s_dev;
+ remap->dest = d_dev;
+ remap->dev = dev;
+ remap->id = id;
+
+ dmu_cpy_flag(&remap->flags, msg->flags, DMU_FLAG_COPY_FIRST);
+ dmu_cpy_flag(&remap->flags, msg->flags, DMU_FLAG_TEMPORARY);
+ dmu_cpy_flag(&remap->flags, msg->flags, DMU_FLAG_SYNC);
+ dmu_cpy_flag(&remap->flags, msg->flags, DMU_FLAG_WR);
+ dmu_cpy_flag(&remap->flags, msg->flags, DMU_FLAG_RD);
+ dmu_clr_flag(&remap->flags, DMU_FLAG_VALID);
+
+ remap->bios = bio_holder;
+
+ spin_unlock(&remap->lock);
+ spin_unlock_irqrestore(&dev->lock, flags);
+
+ if (! is_chained)
+ copy_or_flush(remap);
+
+ return 1;
+
+ bad:
+ DMERR("Remap error: chaos may ensue");
+
+ return 0;
+}
+
+static int version_request(struct dmu_msg_version *msg,
+ struct dmu_device *dev, uint32_t id)
+{
+ struct userspace_request *req;
+
+ req = mempool_alloc(request_pool, GFP_NOIO);
+ if (!req) {
+ DMERR("Failed to alloc version response");
+ return 0;
+ }
+
+ init_request(dev, DM_USERSPACE_GET_VERSION, req);
+ add_request(dev, req);
+
+ return 1;
+}
+
+static int invalidate_request(struct dmu_msg_invalidate_map *msg,
+ struct dmu_device *dev, uint32_t id)
+{
+ struct dmu_map *remap;
+ struct userspace_request *req;
+ int ret = 1;
+ unsigned long flags;
+
+ remap = ht_find_map_dev(dev, msg->org_block);
+ if (!remap)
+ ret = 0;
+ else {
+ spin_lock_irqsave(&dev->lock, flags);
+ spin_lock(&remap->lock); /* IRQs already disabled */
+ if (dmu_get_flag(&remap->flags, DMU_FLAG_VALID))
+ ht_delete_map(&dev->remaps, remap);
+ else
+ ret = 0;
+ spin_unlock(&remap->lock);
+ spin_unlock_irqrestore(&dev->lock, flags);
+ }
+
+ req = mempool_alloc(request_pool, GFP_NOIO);
+ if (!req) {
+ DMERR("Failed to allocate request");
+ return 0;
+ }
+
+ if (ret)
+ init_request(dev, DM_USERSPACE_INVAL_COMPLETE, req);
+ else
+ init_request(dev, DM_USERSPACE_INVAL_FAILED, req);
+
+ req->u.block = msg->org_block;
+ req->id = id;
+
+ add_request(dev, req);
+
+ return ret;
+}
+
+static void sync_complete(struct dmu_device *dev, uint32_t id_of_op) {
+ struct dmu_map *p, *match = NULL;
+ struct bio *bio;
+ unsigned long flags;
+
+ spin_lock_irqsave(&dev->lock, flags);
+ list_for_each_entry(p, &dev->in_flight, in_flight) {
+ if (p->id == id_of_op) {
+ match = p;
+ break;
+ }
+
+ }
+ spin_unlock_irqrestore(&dev->lock, flags);
+
+ if (match) {
+ spin_lock(&match->lock);
+ dmu_clr_flag(&match->flags, DMU_FLAG_WAITING);
+ spin_unlock(&match->lock);
+ while(1) {
+ spin_lock(&match->lock);
+ bio = match->bios_waiting.head;
+ spin_unlock(&match->lock);
+ if (!bio)
+ break;
+ bio->bi_end_io(bio, 0, 0);
+ }
+ } else {
+ DMERR("Unable to complete unknown request %u\n", id_of_op);
+ }
+}
+
+
+ssize_t dmu_ctl_write(struct file *file, const char __user *buffer,
+ size_t size, loff_t *offset)
+{
+ struct dmu_device *dev = (struct dmu_device *)file->private_data;
+ int ret = 0;
+ struct dmu_msg_header hdr;
+ union {
+ struct dmu_msg_map_response map_rsp;
+ struct dmu_msg_invalidate_map inval_rsp;
+ struct dmu_msg_version ver_req;
+ struct dmu_msg_status status_rsp;
+ } msgs;
+
+ if (!capable(CAP_SYS_ADMIN))
+ return -EACCES;
+
+ while ((ret + sizeof(hdr)) < size) {
+ if (copy_from_user(&hdr, buffer+ret, sizeof(hdr))) {
+ DMERR("%s copy_from_user failed!", __FUNCTION__);
+ ret = -EFAULT;
+ goto out;
+ }
+
+ ret += sizeof(hdr);
+
+ switch (hdr.msg_type) {
+
+ case DM_USERSPACE_GET_VERSION:
+ if (hdr.payload_len != sizeof(msgs.ver_req)) {
+ DMERR("Malformed version request");
+ break;
+ }
+
+ if (copy_from_user(&msgs.ver_req, buffer+ret,
+ sizeof(msgs.ver_req))) {
+ DMERR("%s copy_from_user failed!",
+ __FUNCTION__);
+ ret = -EFAULT;
+ goto out;
+ }
+
+ version_request(&msgs.ver_req, dev, hdr.id);
+ break;
+
+ case DM_USERSPACE_MAP_BLOCK_RESP:
+ if (hdr.payload_len != sizeof(msgs.map_rsp)) {
+ DMERR("Malformed block response");
+ break;
+ }
+
+ if (copy_from_user(&msgs.map_rsp, buffer+ret,
+ sizeof(msgs.map_rsp))) {
+ DMERR("%s copy_from_user failed!",
+ __FUNCTION__);
+ ret = -EFAULT;
+ goto out;
+ }
+
+ remap_request(&msgs.map_rsp, dev,
+ msgs.map_rsp.id_of_req);
+ break;
+
+ case DM_USERSPACE_MAP_FAILED:
+ if (hdr.payload_len != sizeof(msgs.map_rsp)) {
+ DMERR("Malformed block failed response");
+ break;
+ }
+
+ if (copy_from_user(&msgs.map_rsp, buffer+ret,
+ sizeof(msgs.map_rsp))) {
+ DMERR("%s copy_from_user failed",
+ __FUNCTION__);
+ ret = -EFAULT;
+ goto out;
+ }
+
+ DMERR("Userspace map failed");
+ break;
+
+ case DM_USERSPACE_MAP_INVALIDATE:
+ if (hdr.payload_len != sizeof(msgs.inval_rsp)) {
+ DMERR("Malformed invalidate request");
+ break;
+ }
+
+ if (copy_from_user(&msgs.inval_rsp, buffer+ret,
+ sizeof(msgs.inval_rsp))) {
+ DMERR("%s copy_from_user failed",
+ __FUNCTION__);
+ ret = -EFAULT;
+ goto out;
+ }
+
+ invalidate_request(&msgs.inval_rsp, dev, hdr.id);
+ break;
+
+ case DM_USERSPACE_STATUS:
+ if (hdr.payload_len != sizeof(msgs.status_rsp)) {
+ DMERR("Malformed invalidate request");
+ break;
+ }
+
+ if (copy_from_user(&msgs.status_rsp, buffer+ret,
+ sizeof(msgs.status_rsp))) {
+ DMERR("%s copy_from_user failed",
+ __FUNCTION__);
+ ret = -EFAULT;
+ goto out;
+ }
+
+ if (msgs.status_rsp.status ==
+ DM_USERSPACE_SYNC_COMPLETE) {
+ sync_complete(dev, msgs.status_rsp.id_of_op);
+ }
+ break;
+
+ default:
+ DMWARN("Unknown request type: %i", hdr.msg_type);
+ }
+
+ ret += hdr.payload_len;
+ }
+ out:
+ return ret;
+}
+
+int dmu_ctl_open(struct inode *inode, struct file *file)
+{
+ struct chardev_transport *t;
+ struct dmu_device *dev;
+
+ if (!capable(CAP_SYS_ADMIN))
+ return -EACCES;
+
+ t = container_of(inode->i_cdev, struct chardev_transport, cdev);
+ dev = t->parent;
+
+ get_dev(dev);
+
+ file->private_data = dev;
+
+ return 0;
+}
+
+int dmu_ctl_release(struct inode *inode, struct file *file)
+{
+ struct dmu_device *dev;
+
+ dev = (struct dmu_device *)file->private_data;
+
+ put_dev(dev);
+
+ return 0;
+}
+
+unsigned dmu_ctl_poll(struct file *file, poll_table *wait)
+{
+ struct dmu_device *dev = (struct dmu_device *)file->private_data;
+ unsigned mask = 0;
+
+ poll_wait(file, &dev->wqueue, wait);
+
+ if (have_pending_requests(dev))
+ mask |= POLLIN | POLLRDNORM;
+
+ return mask;
+}
+
+static struct file_operations ctl_fops = {
+ .open = dmu_ctl_open,
+ .release = dmu_ctl_release,
+ .read = dmu_ctl_read,
+ .write = dmu_ctl_write,
+ .poll = dmu_ctl_poll,
+ .owner = THIS_MODULE,
+};
+
+static int get_free_minor(void)
+{
+ struct dmu_device *dev;
+ int minor = 0;
+
+ spin_lock(&devices_lock);
+
+ while (1) {
+ list_for_each_entry(dev, &devices, list) {
+ struct chardev_transport *t = dev->transport_private;
+ if (MINOR(t->ctl_dev) == minor)
+ goto dupe;
+ }
+ break;
+ dupe:
+ minor++;
+ }
+
+ spin_unlock(&devices_lock);
+
+ return minor;
+}
+
+int register_chardev_transport(struct dmu_device *dev)
+{
+ struct chardev_transport *t;
+ int ret;
+
+ dev->transport_private = kmalloc(sizeof(struct chardev_transport),
+ GFP_KERNEL);
+ t = dev->transport_private;
+
+ if (!t) {
+ DMERR("Failed to allocate chardev transport");
+ goto bad;
+ }
+
+ t->ctl_dev = MKDEV(MAJOR(dmu_dev), get_free_minor());
+ t->parent = dev;
+
+ cdev_init(&t->cdev, &ctl_fops);
+ t->cdev.owner = THIS_MODULE;
+ t->cdev.ops = &ctl_fops;
+
+ ret = cdev_add(&t->cdev, t->ctl_dev, 1);
+ if (ret < 0) {
+ DMERR("Failed to register control device %d:%d",
+ MAJOR(t->ctl_dev), MINOR(t->ctl_dev));
+ goto bad;
+ }
+
+ return 1;
+
+ bad:
+ kfree(t);
+ return 0;
+}
+
+void unregister_chardev_transport(struct dmu_device *dev)
+{
+ struct chardev_transport *t = dev->transport_private;
+
+ cdev_del(&t->cdev);
+ kfree(t);
+}
+
+int init_chardev_transport(void)
+{
+ int r;
+
+ r = alloc_chrdev_region(&dmu_dev, 0, 10, "dm-userspace");
+ if (r) {
+ DMERR("Failed to allocate chardev region");
+ return 0;
+ } else
+ return 1;
+}
+
+void cleanup_chardev_transport(void)
+{
+ unregister_chrdev_region(dmu_dev, 10);
+}
+
+void write_chardev_transport_info(struct dmu_device *dev,
+ char *buf, unsigned int maxlen)
+{
+ struct chardev_transport *t = dev->transport_private;
+
+ snprintf(buf, maxlen, "%x:%x",
+ MAJOR(t->ctl_dev), MINOR(t->ctl_dev));
+}
diff -Naur linux-2.6.17.6-orig/drivers/md/Kconfig linux-2.6.17.6-dmu/drivers/md/Kconfig
--- linux-2.6.17.6-orig/drivers/md/Kconfig 2006-07-15 12:00:43.000000000 -0700
+++ linux-2.6.17.6-dmu/drivers/md/Kconfig 2006-07-27 14:32:05.000000000 -0700
@@ -237,6 +237,12 @@
---help---
Allow volume managers to take writeable snapshots of a device.
+config DM_USERSPACE
+ tristate "Userspace target (EXPERIMENTAL)"
+ depends on BLK_DEV_DM && EXPERIMENTAL
+ ---help---
+ A target that provides a userspace interface to device-mapper
+
config DM_MIRROR
tristate "Mirror target (EXPERIMENTAL)"
depends on BLK_DEV_DM && EXPERIMENTAL
diff -Naur linux-2.6.17.6-orig/drivers/md/Makefile linux-2.6.17.6-dmu/drivers/md/Makefile
--- linux-2.6.17.6-orig/drivers/md/Makefile 2006-07-15 12:00:43.000000000 -0700
+++ linux-2.6.17.6-dmu/drivers/md/Makefile 2006-07-27 14:32:05.000000000 -0700
@@ -14,6 +14,7 @@
raid6altivec1.o raid6altivec2.o raid6altivec4.o \
raid6altivec8.o \
raid6mmx.o raid6sse1.o raid6sse2.o
+dm-user-objs := dm-userspace.o dm-userspace-chardev.o
hostprogs-y := mktables
# Note: link order is important. All raid personalities
@@ -37,6 +38,7 @@
obj-$(CONFIG_DM_SNAPSHOT) += dm-snapshot.o
obj-$(CONFIG_DM_MIRROR) += dm-mirror.o
obj-$(CONFIG_DM_ZERO) += dm-zero.o
+obj-$(CONFIG_DM_USERSPACE) += dm-user.o
quiet_cmd_unroll = UNROLL $@
cmd_unroll = $(PERL) $(srctree)/$(src)/unroll.pl $(UNROLL) \
diff -Naur linux-2.6.17.6-orig/include/linux/dm-userspace.h linux-2.6.17.6-dmu/include/linux/dm-userspace.h
--- linux-2.6.17.6-orig/include/linux/dm-userspace.h 1969-12-31 16:00:00.000000000 -0800
+++ linux-2.6.17.6-dmu/include/linux/dm-userspace.h 2006-07-27 14:32:05.000000000 -0700
@@ -0,0 +1,147 @@
+/*
+ * Copyright (C) International Business Machines Corp., 2006
+ * Author: Dan Smith <danms@...ibm.com>
+ *
+ * This program 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; under version 2 of the License.
+ *
+ * This program 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 this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ *
+ */
+
+#ifndef __DM_USERSPACE_H
+#define __DM_USERSPACE_H
+
+#include <linux/types.h>
+
+/*
+ * Message Types
+ */
+#define DM_USERSPACE_GET_VERSION 1
+#define DM_USERSPACE_MAP_BLOCK_REQ 2
+#define DM_USERSPACE_MAP_BLOCK_RESP 3
+#define DM_USERSPACE_MAP_FAILED 4
+#define DM_USERSPACE_MAP_INVALIDATE 5
+#define DM_USERSPACE_STATUS 6
+
+/*
+ * Status codes
+ */
+#define DM_USERSPACE_INVAL_COMPLETE 101
+#define DM_USERSPACE_INVAL_FAILED 102
+#define DM_USERSPACE_SYNC_COMPLETE 103
+
+/*
+ * Flags and associated macros
+ */
+#define DMU_FLAG_VALID 1
+#define DMU_FLAG_RD 2
+#define DMU_FLAG_WR 4
+#define DMU_FLAG_COPY_FIRST 8
+#define DMU_FLAG_TEMPORARY 16
+#define DMU_FLAG_INUSE 32
+#define DMU_FLAG_SYNC 64
+#define DMU_FLAG_WAITING 128
+
+static int dmu_get_flag(uint32_t *flags, uint32_t flag)
+{
+ return (*flags & flag) != 0;
+}
+
+static void dmu_set_flag(uint32_t *flags, uint32_t flag)
+{
+ *flags |= flag;
+}
+
+static void dmu_clr_flag(uint32_t *flags, uint32_t flag)
+{
+ *flags &= (~flag);
+}
+
+static void dmu_cpy_flag(uint32_t *flags, uint32_t src, uint32_t flag)
+{
+ *flags = (*flags & ~flag) | (src & flag);
+}
+
+/*
+ * This message header is sent in front of every message, in both
+ * directions
+ */
+struct dmu_msg_header {
+ uint32_t msg_type;
+ uint32_t payload_len;
+ uint32_t id;
+};
+
+/* DM_USERSPACE_GET_VERSION */
+struct dmu_msg_version {
+ uint32_t userspace_ver;
+ uint32_t kernel_ver;
+};
+
+/* For status codes */
+struct dmu_msg_status {
+ uint32_t id_of_op;
+ uint32_t status;
+};
+
+/* DM_USERSPACE_MAP_BLOCK_REQ */
+struct dmu_msg_map_request {
+ uint64_t org_block;
+
+ uint32_t flags;
+};
+
+/* DM_USERSPACE_MAP_BLOCK_RESP
+ * DM_USERSPACE_MAP_BLOCK_FAILED
+ */
+struct dmu_msg_map_response {
+ uint64_t org_block;
+ uint64_t new_block;
+ int64_t offset;
+
+ uint32_t id_of_req;
+ uint32_t flags;
+
+ uint32_t src_maj;
+ uint32_t src_min;
+
+ uint32_t dst_maj;
+ uint32_t dst_min;
+};
+
+/* DM_USERSPACE_MAP_INVALIDATE */
+struct dmu_msg_invalidate_map {
+ uint64_t org_block;
+};
+
+static inline int dmu_get_msg_len(int type)
+{
+ switch (type) {
+ case DM_USERSPACE_GET_VERSION:
+ return sizeof(struct dmu_msg_version);
+ case DM_USERSPACE_INVAL_COMPLETE:
+ case DM_USERSPACE_INVAL_FAILED:
+ case DM_USERSPACE_STATUS:
+ return sizeof(struct dmu_msg_status);
+ case DM_USERSPACE_MAP_BLOCK_REQ:
+ return sizeof(struct dmu_msg_map_request);
+ case DM_USERSPACE_MAP_BLOCK_RESP:
+ case DM_USERSPACE_MAP_FAILED:
+ return sizeof(struct dmu_msg_map_response);
+ case DM_USERSPACE_MAP_INVALIDATE:
+ return sizeof(struct dmu_msg_invalidate_map);
+ default:
+ return -1;
+ };
+}
+
+#endif
--
Dan Smith
IBM Linux Technology Center
Open Hypervisor Team
email: danms@...ibm.com
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