Linux-2.6.12-rc2v2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!

1 files changed, 1416 insertions, 0 deletions

diff --git a/drivers/md/dm-ioctl.c b/drivers/md/dm-ioctl.c
new file mode 100644
index 000000000000..ee3c869d9701
--- /dev/null
+++ b/drivers/md/dm-ioctl.c
@@ -0,0 +1,1416 @@
+/*
+ * Copyright (C) 2001, 2002 Sistina Software (UK) Limited.
+ * Copyright (C) 2004 - 2005 Red Hat, Inc. All rights reserved.
+ *
+ * This file is released under the GPL.
+ */
+
+#include "dm.h"
+
+#include <linux/module.h>
+#include <linux/vmalloc.h>
+#include <linux/miscdevice.h>
+#include <linux/init.h>
+#include <linux/wait.h>
+#include <linux/slab.h>
+#include <linux/devfs_fs_kernel.h>
+#include <linux/dm-ioctl.h>
+
+#include <asm/uaccess.h>
+
+#define DM_DRIVER_EMAIL "dm-devel@redhat.com"
+
+/*-----------------------------------------------------------------
+ * The ioctl interface needs to be able to look up devices by
+ * name or uuid.
+ *---------------------------------------------------------------*/
+struct hash_cell {
+        struct list_head name_list;
+        struct list_head uuid_list;
+
+        char *name;
+        char *uuid;
+        struct mapped_device *md;
+        struct dm_table *new_map;
+};
+
+struct vers_iter {
+    size_t param_size;
+    struct dm_target_versions *vers, *old_vers;
+    char *end;
+    uint32_t flags;
+};
+
+
+#define NUM_BUCKETS 64
+#define MASK_BUCKETS (NUM_BUCKETS - 1)
+static struct list_head _name_buckets[NUM_BUCKETS];
+static struct list_head _uuid_buckets[NUM_BUCKETS];
+
+static void dm_hash_remove_all(void);
+
+/*
+ * Guards access to both hash tables.
+ */
+static DECLARE_RWSEM(_hash_lock);
+
+static void init_buckets(struct list_head *buckets)
+{
+        unsigned int i;
+
+        for (i = 0; i < NUM_BUCKETS; i++)
+                INIT_LIST_HEAD(buckets + i);
+}
+
+static int dm_hash_init(void)
+{
+        init_buckets(_name_buckets);
+        init_buckets(_uuid_buckets);
+        devfs_mk_dir(DM_DIR);
+        return 0;
+}
+
+static void dm_hash_exit(void)
+{
+        dm_hash_remove_all();
+        devfs_remove(DM_DIR);
+}
+
+/*-----------------------------------------------------------------
+ * Hash function:
+ * We're not really concerned with the str hash function being
+ * fast since it's only used by the ioctl interface.
+ *---------------------------------------------------------------*/
+static unsigned int hash_str(const char *str)
+{
+        const unsigned int hash_mult = 2654435387U;
+        unsigned int h = 0;
+
+        while (*str)
+                h = (h + (unsigned int) *str++) * hash_mult;
+
+        return h & MASK_BUCKETS;
+}
+
+/*-----------------------------------------------------------------
+ * Code for looking up a device by name
+ *---------------------------------------------------------------*/
+static struct hash_cell *__get_name_cell(const char *str)
+{
+        struct hash_cell *hc;
+        unsigned int h = hash_str(str);
+
+        list_for_each_entry (hc, _name_buckets + h, name_list)
+                if (!strcmp(hc->name, str))
+                        return hc;
+
+        return NULL;
+}
+
+static struct hash_cell *__get_uuid_cell(const char *str)
+{
+        struct hash_cell *hc;
+        unsigned int h = hash_str(str);
+
+        list_for_each_entry (hc, _uuid_buckets + h, uuid_list)
+                if (!strcmp(hc->uuid, str))
+                        return hc;
+
+        return NULL;
+}
+
+/*-----------------------------------------------------------------
+ * Inserting, removing and renaming a device.
+ *---------------------------------------------------------------*/
+static inline char *kstrdup(const char *str)
+{
+        char *r = kmalloc(strlen(str) + 1, GFP_KERNEL);
+        if (r)
+                strcpy(r, str);
+        return r;
+}
+
+static struct hash_cell *alloc_cell(const char *name, const char *uuid,
+                                    struct mapped_device *md)
+{
+        struct hash_cell *hc;
+
+        hc = kmalloc(sizeof(*hc), GFP_KERNEL);
+        if (!hc)
+                return NULL;
+
+        hc->name = kstrdup(name);
+        if (!hc->name) {
+                kfree(hc);
+                return NULL;
+        }
+
+        if (!uuid)
+                hc->uuid = NULL;
+
+        else {
+                hc->uuid = kstrdup(uuid);
+                if (!hc->uuid) {
+                        kfree(hc->name);
+                        kfree(hc);
+                        return NULL;
+                }
+        }
+
+        INIT_LIST_HEAD(&hc->name_list);
+        INIT_LIST_HEAD(&hc->uuid_list);
+        hc->md = md;
+        hc->new_map = NULL;
+        return hc;
+}
+
+static void free_cell(struct hash_cell *hc)
+{
+        if (hc) {
+                kfree(hc->name);
+                kfree(hc->uuid);
+                kfree(hc);
+        }
+}
+
+/*
+ * devfs stuff.
+ */
+static int register_with_devfs(struct hash_cell *hc)
+{
+        struct gendisk *disk = dm_disk(hc->md);
+
+        devfs_mk_bdev(MKDEV(disk->major, disk->first_minor),
+                      S_IFBLK | S_IRUSR | S_IWUSR | S_IRGRP,
+                      DM_DIR "/%s", hc->name);
+        return 0;
+}
+
+static int unregister_with_devfs(struct hash_cell *hc)
+{
+        devfs_remove(DM_DIR"/%s", hc->name);
+        return 0;
+}
+
+/*
+ * The kdev_t and uuid of a device can never change once it is
+ * initially inserted.
+ */
+static int dm_hash_insert(const char *name, const char *uuid, struct mapped_device *md)
+{
+        struct hash_cell *cell;
+
+        /*
+         * Allocate the new cells.
+         */
+        cell = alloc_cell(name, uuid, md);
+        if (!cell)
+                return -ENOMEM;
+
+        /*
+         * Insert the cell into both hash tables.
+         */
+        down_write(&_hash_lock);
+        if (__get_name_cell(name))
+                goto bad;
+
+        list_add(&cell->name_list, _name_buckets + hash_str(name));
+
+        if (uuid) {
+                if (__get_uuid_cell(uuid)) {
+                        list_del(&cell->name_list);
+                        goto bad;
+                }
+                list_add(&cell->uuid_list, _uuid_buckets + hash_str(uuid));
+        }
+        register_with_devfs(cell);
+        dm_get(md);
+        dm_set_mdptr(md, cell);
+        up_write(&_hash_lock);
+
+        return 0;
+
+ bad:
+        up_write(&_hash_lock);
+        free_cell(cell);
+        return -EBUSY;
+}
+
+static void __hash_remove(struct hash_cell *hc)
+{
+        /* remove from the dev hash */
+        list_del(&hc->uuid_list);
+        list_del(&hc->name_list);
+        unregister_with_devfs(hc);
+        dm_set_mdptr(hc->md, NULL);
+        dm_put(hc->md);
+        if (hc->new_map)
+                dm_table_put(hc->new_map);
+        free_cell(hc);
+}
+
+static void dm_hash_remove_all(void)
+{
+        int i;
+        struct hash_cell *hc;
+        struct list_head *tmp, *n;
+
+        down_write(&_hash_lock);
+        for (i = 0; i < NUM_BUCKETS; i++) {
+                list_for_each_safe (tmp, n, _name_buckets + i) {
+                        hc = list_entry(tmp, struct hash_cell, name_list);
+                        __hash_remove(hc);
+                }
+        }
+        up_write(&_hash_lock);
+}
+
+static int dm_hash_rename(const char *old, const char *new)
+{
+        char *new_name, *old_name;
+        struct hash_cell *hc;
+
+        /*
+         * duplicate new.
+         */
+        new_name = kstrdup(new);
+        if (!new_name)
+                return -ENOMEM;
+
+        down_write(&_hash_lock);
+
+        /*
+         * Is new free ?
+         */
+        hc = __get_name_cell(new);
+        if (hc) {
+                DMWARN("asked to rename to an already existing name %s -> %s",
+                       old, new);
+                up_write(&_hash_lock);
+                kfree(new_name);
+                return -EBUSY;
+        }
+
+        /*
+         * Is there such a device as 'old' ?
+         */
+        hc = __get_name_cell(old);
+        if (!hc) {
+                DMWARN("asked to rename a non existent device %s -> %s",
+                       old, new);
+                up_write(&_hash_lock);
+                kfree(new_name);
+                return -ENXIO;
+        }
+
+        /*
+         * rename and move the name cell.
+         */
+        unregister_with_devfs(hc);
+
+        list_del(&hc->name_list);
+        old_name = hc->name;
+        hc->name = new_name;
+        list_add(&hc->name_list, _name_buckets + hash_str(new_name));
+
+        /* rename the device node in devfs */
+        register_with_devfs(hc);
+
+        up_write(&_hash_lock);
+        kfree(old_name);
+        return 0;
+}
+
+/*-----------------------------------------------------------------
+ * Implementation of the ioctl commands
+ *---------------------------------------------------------------*/
+/*
+ * All the ioctl commands get dispatched to functions with this
+ * prototype.
+ */
+typedef int (*ioctl_fn)(struct dm_ioctl *param, size_t param_size);
+
+static int remove_all(struct dm_ioctl *param, size_t param_size)
+{
+        dm_hash_remove_all();
+        param->data_size = 0;
+        return 0;
+}
+
+/*
+ * Round up the ptr to an 8-byte boundary.
+ */
+#define ALIGN_MASK 7
+static inline void *align_ptr(void *ptr)
+{
+        return (void *) (((size_t) (ptr + ALIGN_MASK)) & ~ALIGN_MASK);
+}
+
+/*
+ * Retrieves the data payload buffer from an already allocated
+ * struct dm_ioctl.
+ */
+static void *get_result_buffer(struct dm_ioctl *param, size_t param_size,
+                               size_t *len)
+{
+        param->data_start = align_ptr(param + 1) - (void *) param;
+
+        if (param->data_start < param_size)
+                *len = param_size - param->data_start;
+        else
+                *len = 0;
+
+        return ((void *) param) + param->data_start;
+}
+
+static int list_devices(struct dm_ioctl *param, size_t param_size)
+{
+        unsigned int i;
+        struct hash_cell *hc;
+        size_t len, needed = 0;
+        struct gendisk *disk;
+        struct dm_name_list *nl, *old_nl = NULL;
+
+        down_write(&_hash_lock);
+
+        /*
+         * Loop through all the devices working out how much
+         * space we need.
+         */
+        for (i = 0; i < NUM_BUCKETS; i++) {
+                list_for_each_entry (hc, _name_buckets + i, name_list) {
+                        needed += sizeof(struct dm_name_list);
+                        needed += strlen(hc->name) + 1;
+                        needed += ALIGN_MASK;
+                }
+        }
+
+        /*
+         * Grab our output buffer.
+         */
+        nl = get_result_buffer(param, param_size, &len);
+        if (len < needed) {
+                param->flags |= DM_BUFFER_FULL_FLAG;
+                goto out;
+        }
+        param->data_size = param->data_start + needed;
+
+        nl->dev = 0;    /* Flags no data */
+
+        /*
+         * Now loop through filling out the names.
+         */
+        for (i = 0; i < NUM_BUCKETS; i++) {
+                list_for_each_entry (hc, _name_buckets + i, name_list) {
+                        if (old_nl)
+                                old_nl->next = (uint32_t) ((void *) nl -
+                                                           (void *) old_nl);
+                        disk = dm_disk(hc->md);
+                        nl->dev = huge_encode_dev(MKDEV(disk->major, disk->first_minor));
+                        nl->next = 0;
+                        strcpy(nl->name, hc->name);
+
+                        old_nl = nl;
+                        nl = align_ptr(((void *) ++nl) + strlen(hc->name) + 1);
+                }
+        }
+
+ out:
+        up_write(&_hash_lock);
+        return 0;
+}
+
+static void list_version_get_needed(struct target_type *tt, void *needed_param)
+{
+    size_t *needed = needed_param;
+
+    *needed += strlen(tt->name);
+    *needed += sizeof(tt->version);
+    *needed += ALIGN_MASK;
+}
+
+static void list_version_get_info(struct target_type *tt, void *param)
+{
+    struct vers_iter *info = param;
+
+    /* Check space - it might have changed since the first iteration */
+    if ((char *)info->vers + sizeof(tt->version) + strlen(tt->name) + 1 >
+        info->end) {
+
+        info->flags = DM_BUFFER_FULL_FLAG;
+        return;
+    }
+
+    if (info->old_vers)
+        info->old_vers->next = (uint32_t) ((void *)info->vers -
+                                           (void *)info->old_vers);
+    info->vers->version[0] = tt->version[0];
+    info->vers->version[1] = tt->version[1];
+    info->vers->version[2] = tt->version[2];
+    info->vers->next = 0;
+    strcpy(info->vers->name, tt->name);
+
+    info->old_vers = info->vers;
+    info->vers = align_ptr(((void *) ++info->vers) + strlen(tt->name) + 1);
+}
+
+static int list_versions(struct dm_ioctl *param, size_t param_size)
+{
+        size_t len, needed = 0;
+        struct dm_target_versions *vers;
+        struct vers_iter iter_info;
+
+        /*
+         * Loop through all the devices working out how much
+         * space we need.
+         */
+        dm_target_iterate(list_version_get_needed, &needed);
+
+        /*
+         * Grab our output buffer.
+         */
+        vers = get_result_buffer(param, param_size, &len);
+        if (len < needed) {
+                param->flags |= DM_BUFFER_FULL_FLAG;
+                goto out;
+        }
+        param->data_size = param->data_start + needed;
+
+        iter_info.param_size = param_size;
+        iter_info.old_vers = NULL;
+        iter_info.vers = vers;
+        iter_info.flags = 0;
+        iter_info.end = (char *)vers+len;
+
+        /*
+         * Now loop through filling out the names & versions.
+         */
+        dm_target_iterate(list_version_get_info, &iter_info);
+        param->flags |= iter_info.flags;
+
+ out:
+        return 0;
+}
+
+
+
+static int check_name(const char *name)
+{
+        if (strchr(name, '/')) {
+                DMWARN("invalid device name");
+                return -EINVAL;
+        }
+
+        return 0;
+}
+
+/*
+ * Fills in a dm_ioctl structure, ready for sending back to
+ * userland.
+ */
+static int __dev_status(struct mapped_device *md, struct dm_ioctl *param)
+{
+        struct gendisk *disk = dm_disk(md);
+        struct dm_table *table;
+        struct block_device *bdev;
+
+        param->flags &= ~(DM_SUSPEND_FLAG | DM_READONLY_FLAG |
+                          DM_ACTIVE_PRESENT_FLAG);
+
+        if (dm_suspended(md))
+                param->flags |= DM_SUSPEND_FLAG;
+
+        param->dev = huge_encode_dev(MKDEV(disk->major, disk->first_minor));
+
+        if (!(param->flags & DM_SKIP_BDGET_FLAG)) {
+                bdev = bdget_disk(disk, 0);
+                if (!bdev)
+                        return -ENXIO;
+
+                /*
+                 * Yes, this will be out of date by the time it gets back
+                 * to userland, but it is still very useful for
+                 * debugging.
+                 */
+                param->open_count = bdev->bd_openers;
+                bdput(bdev);
+        } else
+                param->open_count = -1;
+
+        if (disk->policy)
+                param->flags |= DM_READONLY_FLAG;
+
+        param->event_nr = dm_get_event_nr(md);
+
+        table = dm_get_table(md);
+        if (table) {
+                param->flags |= DM_ACTIVE_PRESENT_FLAG;
+                param->target_count = dm_table_get_num_targets(table);
+                dm_table_put(table);
+        } else
+                param->target_count = 0;
+
+        return 0;
+}
+
+static int dev_create(struct dm_ioctl *param, size_t param_size)
+{
+        int r;
+        struct mapped_device *md;
+
+        r = check_name(param->name);
+        if (r)
+                return r;
+
+        if (param->flags & DM_PERSISTENT_DEV_FLAG)
+                r = dm_create_with_minor(MINOR(huge_decode_dev(param->dev)), &md);
+        else
+                r = dm_create(&md);
+
+        if (r)
+                return r;
+
+        r = dm_hash_insert(param->name, *param->uuid ? param->uuid : NULL, md);
+        if (r) {
+                dm_put(md);
+                return r;
+        }
+
+        param->flags &= ~DM_INACTIVE_PRESENT_FLAG;
+
+        r = __dev_status(md, param);
+        dm_put(md);
+
+        return r;
+}
+
+/*
+ * Always use UUID for lookups if it's present, otherwise use name or dev.
+ */
+static inline struct hash_cell *__find_device_hash_cell(struct dm_ioctl *param)
+{
+        if (*param->uuid)
+                return __get_uuid_cell(param->uuid);
+        else if (*param->name)
+                return __get_name_cell(param->name);
+        else
+                return dm_get_mdptr(huge_decode_dev(param->dev));
+}
+
+static inline struct mapped_device *find_device(struct dm_ioctl *param)
+{
+        struct hash_cell *hc;
+        struct mapped_device *md = NULL;
+
+        down_read(&_hash_lock);
+        hc = __find_device_hash_cell(param);
+        if (hc) {
+                md = hc->md;
+                dm_get(md);
+
+                /*
+                 * Sneakily write in both the name and the uuid
+                 * while we have the cell.
+                 */
+                strncpy(param->name, hc->name, sizeof(param->name));
+                if (hc->uuid)
+                        strncpy(param->uuid, hc->uuid, sizeof(param->uuid)-1);
+                else
+                        param->uuid[0] = '\0';
+
+                if (hc->new_map)
+                        param->flags |= DM_INACTIVE_PRESENT_FLAG;
+                else
+                        param->flags &= ~DM_INACTIVE_PRESENT_FLAG;
+        }
+        up_read(&_hash_lock);
+
+        return md;
+}
+
+static int dev_remove(struct dm_ioctl *param, size_t param_size)
+{
+        struct hash_cell *hc;
+
+        down_write(&_hash_lock);
+        hc = __find_device_hash_cell(param);
+
+        if (!hc) {
+                DMWARN("device doesn't appear to be in the dev hash table.");
+                up_write(&_hash_lock);
+                return -ENXIO;
+        }
+
+        __hash_remove(hc);
+        up_write(&_hash_lock);
+        param->data_size = 0;
+        return 0;
+}
+
+/*
+ * Check a string doesn't overrun the chunk of
+ * memory we copied from userland.
+ */
+static int invalid_str(char *str, void *end)
+{
+        while ((void *) str < end)
+                if (!*str++)
+                        return 0;
+
+        return -EINVAL;
+}
+
+static int dev_rename(struct dm_ioctl *param, size_t param_size)
+{
+        int r;
+        char *new_name = (char *) param + param->data_start;
+
+        if (new_name < (char *) (param + 1) ||
+            invalid_str(new_name, (void *) param + param_size)) {
+                DMWARN("Invalid new logical volume name supplied.");
+                return -EINVAL;
+        }
+
+        r = check_name(new_name);
+        if (r)
+                return r;
+
+        param->data_size = 0;
+        return dm_hash_rename(param->name, new_name);
+}
+
+static int do_suspend(struct dm_ioctl *param)
+{
+        int r = 0;
+        struct mapped_device *md;
+
+        md = find_device(param);
+        if (!md)
+                return -ENXIO;
+
+        if (!dm_suspended(md))
+                r = dm_suspend(md);
+
+        if (!r)
+                r = __dev_status(md, param);
+
+        dm_put(md);
+        return r;
+}
+
+static int do_resume(struct dm_ioctl *param)
+{
+        int r = 0;
+        struct hash_cell *hc;
+        struct mapped_device *md;
+        struct dm_table *new_map;
+
+        down_write(&_hash_lock);
+
+        hc = __find_device_hash_cell(param);
+        if (!hc) {
+                DMWARN("device doesn't appear to be in the dev hash table.");
+                up_write(&_hash_lock);
+                return -ENXIO;
+        }
+
+        md = hc->md;
+        dm_get(md);
+
+        new_map = hc->new_map;
+        hc->new_map = NULL;
+        param->flags &= ~DM_INACTIVE_PRESENT_FLAG;
+
+        up_write(&_hash_lock);
+
+        /* Do we need to load a new map ? */
+        if (new_map) {
+                /* Suspend if it isn't already suspended */
+                if (!dm_suspended(md))
+                        dm_suspend(md);
+
+                r = dm_swap_table(md, new_map);
+                if (r) {
+                        dm_put(md);
+                        dm_table_put(new_map);
+                        return r;
+                }
+
+                if (dm_table_get_mode(new_map) & FMODE_WRITE)
+                        set_disk_ro(dm_disk(md), 0);
+                else
+                        set_disk_ro(dm_disk(md), 1);
+
+                dm_table_put(new_map);
+        }
+
+        if (dm_suspended(md))
+                r = dm_resume(md);
+
+        if (!r)
+                r = __dev_status(md, param);
+
+        dm_put(md);
+        return r;
+}
+
+/*
+ * Set or unset the suspension state of a device.
+ * If the device already is in the requested state we just return its status.
+ */
+static int dev_suspend(struct dm_ioctl *param, size_t param_size)
+{
+        if (param->flags & DM_SUSPEND_FLAG)
+                return do_suspend(param);
+
+        return do_resume(param);
+}
+
+/*
+ * Copies device info back to user space, used by
+ * the create and info ioctls.
+ */
+static int dev_status(struct dm_ioctl *param, size_t param_size)
+{
+        int r;
+        struct mapped_device *md;
+
+        md = find_device(param);
+        if (!md)
+                return -ENXIO;
+
+        r = __dev_status(md, param);
+        dm_put(md);
+        return r;
+}
+
+/*
+ * Build up the status struct for each target
+ */
+static void retrieve_status(struct dm_table *table,
+                            struct dm_ioctl *param, size_t param_size)
+{
+        unsigned int i, num_targets;
+        struct dm_target_spec *spec;
+        char *outbuf, *outptr;
+        status_type_t type;
+        size_t remaining, len, used = 0;
+
+        outptr = outbuf = get_result_buffer(param, param_size, &len);
+
+        if (param->flags & DM_STATUS_TABLE_FLAG)
+                type = STATUSTYPE_TABLE;
+        else
+                type = STATUSTYPE_INFO;
+
+        /* Get all the target info */
+        num_targets = dm_table_get_num_targets(table);
+        for (i = 0; i < num_targets; i++) {
+                struct dm_target *ti = dm_table_get_target(table, i);
+
+                remaining = len - (outptr - outbuf);
+                if (remaining <= sizeof(struct dm_target_spec)) {
+                        param->flags |= DM_BUFFER_FULL_FLAG;
+                        break;
+                }
+
+                spec = (struct dm_target_spec *) outptr;
+
+                spec->status = 0;
+                spec->sector_start = ti->begin;
+                spec->length = ti->len;
+                strncpy(spec->target_type, ti->type->name,
+                        sizeof(spec->target_type));
+
+                outptr += sizeof(struct dm_target_spec);
+                remaining = len - (outptr - outbuf);
+                if (remaining <= 0) {
+                        param->flags |= DM_BUFFER_FULL_FLAG;
+                        break;
+                }
+
+                /* Get the status/table string from the target driver */
+                if (ti->type->status) {
+                        if (ti->type->status(ti, type, outptr, remaining)) {
+                                param->flags |= DM_BUFFER_FULL_FLAG;
+                                break;
+                        }
+                } else
+                        outptr[0] = '\0';
+
+                outptr += strlen(outptr) + 1;
+                used = param->data_start + (outptr - outbuf);
+
+                outptr = align_ptr(outptr);
+                spec->next = outptr - outbuf;
+        }
+
+        if (used)
+                param->data_size = used;
+
+        param->target_count = num_targets;
+}
+
+/*
+ * Wait for a device to report an event
+ */
+static int dev_wait(struct dm_ioctl *param, size_t param_size)
+{
+        int r;
+        struct mapped_device *md;
+        struct dm_table *table;
+
+        md = find_device(param);
+        if (!md)
+                return -ENXIO;
+
+        /*
+         * Wait for a notification event
+         */
+        if (dm_wait_event(md, param->event_nr)) {
+                r = -ERESTARTSYS;
+                goto out;
+        }
+
+        /*
+         * The userland program is going to want to know what
+         * changed to trigger the event, so we may as well tell
+         * him and save an ioctl.
+         */
+        r = __dev_status(md, param);
+        if (r)
+                goto out;
+
+        table = dm_get_table(md);
+        if (table) {
+                retrieve_status(table, param, param_size);
+                dm_table_put(table);
+        }
+
+ out:
+        dm_put(md);
+        return r;
+}
+
+static inline int get_mode(struct dm_ioctl *param)
+{
+        int mode = FMODE_READ | FMODE_WRITE;
+
+        if (param->flags & DM_READONLY_FLAG)
+                mode = FMODE_READ;
+
+        return mode;
+}
+
+static int next_target(struct dm_target_spec *last, uint32_t next, void *end,
+                       struct dm_target_spec **spec, char **target_params)
+{
+        *spec = (struct dm_target_spec *) ((unsigned char *) last + next);
+        *target_params = (char *) (*spec + 1);
+
+        if (*spec < (last + 1))
+                return -EINVAL;
+
+        return invalid_str(*target_params, end);
+}
+
+static int populate_table(struct dm_table *table,
+                          struct dm_ioctl *param, size_t param_size)
+{
+        int r;
+        unsigned int i = 0;
+        struct dm_target_spec *spec = (struct dm_target_spec *) param;
+        uint32_t next = param->data_start;
+        void *end = (void *) param + param_size;
+        char *target_params;
+
+        if (!param->target_count) {
+                DMWARN("populate_table: no targets specified");
+                return -EINVAL;
+        }
+
+        for (i = 0; i < param->target_count; i++) {
+
+                r = next_target(spec, next, end, &spec, &target_params);
+                if (r) {
+                        DMWARN("unable to find target");
+                        return r;
+                }
+
+                r = dm_table_add_target(table, spec->target_type,
+                                        (sector_t) spec->sector_start,
+                                        (sector_t) spec->length,
+                                        target_params);
+                if (r) {
+                        DMWARN("error adding target to table");
+                        return r;
+                }
+
+                next = spec->next;
+        }
+
+        return dm_table_complete(table);
+}
+
+static int table_load(struct dm_ioctl *param, size_t param_size)
+{
+        int r;
+        struct hash_cell *hc;
+        struct dm_table *t;
+
+        r = dm_table_create(&t, get_mode(param), param->target_count);
+        if (r)
+                return r;
+
+        r = populate_table(t, param, param_size);
+        if (r) {
+                dm_table_put(t);
+                return r;
+        }
+
+        down_write(&_hash_lock);
+        hc = __find_device_hash_cell(param);
+        if (!hc) {
+                DMWARN("device doesn't appear to be in the dev hash table.");
+                up_write(&_hash_lock);
+                return -ENXIO;
+        }
+
+        if (hc->new_map)
+                dm_table_put(hc->new_map);
+        hc->new_map = t;
+        param->flags |= DM_INACTIVE_PRESENT_FLAG;
+
+        r = __dev_status(hc->md, param);
+        up_write(&_hash_lock);
+        return r;
+}
+
+static int table_clear(struct dm_ioctl *param, size_t param_size)
+{
+        int r;
+        struct hash_cell *hc;
+
+        down_write(&_hash_lock);
+
+        hc = __find_device_hash_cell(param);
+        if (!hc) {
+                DMWARN("device doesn't appear to be in the dev hash table.");
+                up_write(&_hash_lock);
+                return -ENXIO;
+        }
+
+        if (hc->new_map) {
+                dm_table_put(hc->new_map);
+                hc->new_map = NULL;
+        }
+
+        param->flags &= ~DM_INACTIVE_PRESENT_FLAG;
+
+        r = __dev_status(hc->md, param);
+        up_write(&_hash_lock);
+        return r;
+}
+
+/*
+ * Retrieves a list of devices used by a particular dm device.
+ */
+static void retrieve_deps(struct dm_table *table,
+                          struct dm_ioctl *param, size_t param_size)
+{
+        unsigned int count = 0;
+        struct list_head *tmp;
+        size_t len, needed;
+        struct dm_dev *dd;
+        struct dm_target_deps *deps;
+
+        deps = get_result_buffer(param, param_size, &len);
+
+        /*
+         * Count the devices.
+         */
+        list_for_each (tmp, dm_table_get_devices(table))
+                count++;
+
+        /*
+         * Check we have enough space.
+         */
+        needed = sizeof(*deps) + (sizeof(*deps->dev) * count);
+        if (len < needed) {
+                param->flags |= DM_BUFFER_FULL_FLAG;
+                return;
+        }
+
+        /*
+         * Fill in the devices.
+         */
+        deps->count = count;
+        count = 0;
+        list_for_each_entry (dd, dm_table_get_devices(table), list)
+                deps->dev[count++] = huge_encode_dev(dd->bdev->bd_dev);
+
+        param->data_size = param->data_start + needed;
+}
+
+static int table_deps(struct dm_ioctl *param, size_t param_size)
+{
+        int r = 0;
+        struct mapped_device *md;
+        struct dm_table *table;
+
+        md = find_device(param);
+        if (!md)
+                return -ENXIO;
+
+        r = __dev_status(md, param);
+        if (r)
+                goto out;
+
+        table = dm_get_table(md);
+        if (table) {
+                retrieve_deps(table, param, param_size);
+                dm_table_put(table);
+        }
+
+ out:
+        dm_put(md);
+        return r;
+}
+
+/*
+ * Return the status of a device as a text string for each
+ * target.
+ */
+static int table_status(struct dm_ioctl *param, size_t param_size)
+{
+        int r;
+        struct mapped_device *md;
+        struct dm_table *table;
+
+        md = find_device(param);
+        if (!md)
+                return -ENXIO;
+
+        r = __dev_status(md, param);
+        if (r)
+                goto out;
+
+        table = dm_get_table(md);
+        if (table) {
+                retrieve_status(table, param, param_size);
+                dm_table_put(table);
+        }
+
+ out:
+        dm_put(md);
+        return r;
+}
+
+/*
+ * Pass a message to the target that's at the supplied device offset.
+ */
+static int target_message(struct dm_ioctl *param, size_t param_size)
+{
+        int r, argc;
+        char **argv;
+        struct mapped_device *md;
+        struct dm_table *table;
+        struct dm_target *ti;
+        struct dm_target_msg *tmsg = (void *) param + param->data_start;
+
+        md = find_device(param);
+        if (!md)
+                return -ENXIO;
+
+        r = __dev_status(md, param);
+        if (r)
+                goto out;
+
+        if (tmsg < (struct dm_target_msg *) (param + 1) ||
+            invalid_str(tmsg->message, (void *) param + param_size)) {
+                DMWARN("Invalid target message parameters.");
+                r = -EINVAL;
+                goto out;
+        }
+
+        r = dm_split_args(&argc, &argv, tmsg->message);
+        if (r) {
+                DMWARN("Failed to split target message parameters");
+                goto out;
+        }
+
+        table = dm_get_table(md);
+        if (!table)
+                goto out_argv;
+
+        if (tmsg->sector >= dm_table_get_size(table)) {
+                DMWARN("Target message sector outside device.");
+                r = -EINVAL;
+                goto out_table;
+        }
+
+        ti = dm_table_find_target(table, tmsg->sector);
+        if (ti->type->message)
+                r = ti->type->message(ti, argc, argv);
+        else {
+                DMWARN("Target type does not support messages");
+                r = -EINVAL;
+        }
+
+ out_table:
+        dm_table_put(table);
+ out_argv:
+        kfree(argv);
+ out:
+        param->data_size = 0;
+        dm_put(md);
+        return r;
+}
+
+/*-----------------------------------------------------------------
+ * Implementation of open/close/ioctl on the special char
+ * device.
+ *---------------------------------------------------------------*/
+static ioctl_fn lookup_ioctl(unsigned int cmd)
+{
+        static struct {
+                int cmd;
+                ioctl_fn fn;
+        } _ioctls[] = {
+                {DM_VERSION_CMD, NULL}, /* version is dealt with elsewhere */
+                {DM_REMOVE_ALL_CMD, remove_all},
+                {DM_LIST_DEVICES_CMD, list_devices},
+
+                {DM_DEV_CREATE_CMD, dev_create},
+                {DM_DEV_REMOVE_CMD, dev_remove},
+                {DM_DEV_RENAME_CMD, dev_rename},
+                {DM_DEV_SUSPEND_CMD, dev_suspend},
+                {DM_DEV_STATUS_CMD, dev_status},
+                {DM_DEV_WAIT_CMD, dev_wait},
+
+                {DM_TABLE_LOAD_CMD, table_load},
+                {DM_TABLE_CLEAR_CMD, table_clear},
+                {DM_TABLE_DEPS_CMD, table_deps},
+                {DM_TABLE_STATUS_CMD, table_status},
+
+                {DM_LIST_VERSIONS_CMD, list_versions},
+
+                {DM_TARGET_MSG_CMD, target_message}
+        };
+
+        return (cmd >= ARRAY_SIZE(_ioctls)) ? NULL : _ioctls[cmd].fn;
+}
+
+/*
+ * As well as checking the version compatibility this always
+ * copies the kernel interface version out.
+ */
+static int check_version(unsigned int cmd, struct dm_ioctl __user *user)
+{
+        uint32_t version[3];
+        int r = 0;
+
+        if (copy_from_user(version, user->version, sizeof(version)))
+                return -EFAULT;
+
+        if ((DM_VERSION_MAJOR != version[0]) ||
+            (DM_VERSION_MINOR < version[1])) {
+                DMWARN("ioctl interface mismatch: "
+                       "kernel(%u.%u.%u), user(%u.%u.%u), cmd(%d)",
+                       DM_VERSION_MAJOR, DM_VERSION_MINOR,
+                       DM_VERSION_PATCHLEVEL,
+                       version[0], version[1], version[2], cmd);
+                r = -EINVAL;
+        }
+
+        /*
+         * Fill in the kernel version.
+         */
+        version[0] = DM_VERSION_MAJOR;
+        version[1] = DM_VERSION_MINOR;
+        version[2] = DM_VERSION_PATCHLEVEL;
+        if (copy_to_user(user->version, version, sizeof(version)))
+                return -EFAULT;
+
+        return r;
+}
+
+static void free_params(struct dm_ioctl *param)
+{
+        vfree(param);
+}
+
+static int copy_params(struct dm_ioctl __user *user, struct dm_ioctl **param)
+{
+        struct dm_ioctl tmp, *dmi;
+
+        if (copy_from_user(&tmp, user, sizeof(tmp)))
+                return -EFAULT;
+
+        if (tmp.data_size < sizeof(tmp))
+                return -EINVAL;
+
+        dmi = (struct dm_ioctl *) vmalloc(tmp.data_size);
+        if (!dmi)
+                return -ENOMEM;
+
+        if (copy_from_user(dmi, user, tmp.data_size)) {
+                vfree(dmi);
+                return -EFAULT;
+        }
+
+        *param = dmi;
+        return 0;
+}
+
+static int validate_params(uint cmd, struct dm_ioctl *param)
+{
+        /* Always clear this flag */
+        param->flags &= ~DM_BUFFER_FULL_FLAG;
+
+        /* Ignores parameters */
+        if (cmd == DM_REMOVE_ALL_CMD ||
+            cmd == DM_LIST_DEVICES_CMD ||
+            cmd == DM_LIST_VERSIONS_CMD)
+                return 0;
+
+        if ((cmd == DM_DEV_CREATE_CMD)) {
+                if (!*param->name) {
+                        DMWARN("name not supplied when creating device");
+                        return -EINVAL;
+                }
+        } else if ((*param->uuid && *param->name)) {
+                DMWARN("only supply one of name or uuid, cmd(%u)", cmd);
+                return -EINVAL;
+        }
+
+        /* Ensure strings are terminated */
+        param->name[DM_NAME_LEN - 1] = '\0';
+        param->uuid[DM_UUID_LEN - 1] = '\0';
+
+        return 0;
+}
+
+static int ctl_ioctl(struct inode *inode, struct file *file,
+                     uint command, ulong u)
+{
+        int r = 0;
+        unsigned int cmd;
+        struct dm_ioctl *param;
+        struct dm_ioctl __user *user = (struct dm_ioctl __user *) u;
+        ioctl_fn fn = NULL;
+        size_t param_size;
+
+        /* only root can play with this */
+        if (!capable(CAP_SYS_ADMIN))
+                return -EACCES;
+
+        if (_IOC_TYPE(command) != DM_IOCTL)
+                return -ENOTTY;
+
+        cmd = _IOC_NR(command);
+
+        /*
+         * Check the interface version passed in.  This also
+         * writes out the kernel's interface version.
+         */
+        r = check_version(cmd, user);
+        if (r)
+                return r;
+
+        /*
+         * Nothing more to do for the version command.
+         */
+        if (cmd == DM_VERSION_CMD)
+                return 0;
+
+        fn = lookup_ioctl(cmd);
+        if (!fn) {
+                DMWARN("dm_ctl_ioctl: unknown command 0x%x", command);
+                return -ENOTTY;
+        }
+
+        /*
+         * Trying to avoid low memory issues when a device is
+         * suspended.
+         */
+        current->flags |= PF_MEMALLOC;
+
+        /*
+         * Copy the parameters into kernel space.
+         */
+        r = copy_params(user, &param);
+        if (r) {
+                current->flags &= ~PF_MEMALLOC;
+                return r;
+        }
+
+        /*
+         * FIXME: eventually we will remove the PF_MEMALLOC flag
+         * here.  However the tools still do nasty things like
+         * 'load' while a device is suspended.
+         */
+
+        r = validate_params(cmd, param);
+        if (r)
+                goto out;
+
+        param_size = param->data_size;
+        param->data_size = sizeof(*param);
+        r = fn(param, param_size);
+
+        /*
+         * Copy the results back to userland.
+         */
+        if (!r && copy_to_user(user, param, param->data_size))
+                r = -EFAULT;
+
+ out:
+        free_params(param);
+        current->flags &= ~PF_MEMALLOC;
+        return r;
+}
+
+static struct file_operations _ctl_fops = {
+        .ioctl   = ctl_ioctl,
+        .owner   = THIS_MODULE,
+};
+
+static struct miscdevice _dm_misc = {
+        .minor          = MISC_DYNAMIC_MINOR,
+        .name           = DM_NAME,
+        .devfs_name     = "mapper/control",
+        .fops           = &_ctl_fops
+};
+
+/*
+ * Create misc character device and link to DM_DIR/control.
+ */
+int __init dm_interface_init(void)
+{
+        int r;
+
+        r = dm_hash_init();
+        if (r)
+                return r;
+
+        r = misc_register(&_dm_misc);
+        if (r) {
+                DMERR("misc_register failed for control device");
+                dm_hash_exit();
+                return r;
+        }
+
+        DMINFO("%d.%d.%d%s initialised: %s", DM_VERSION_MAJOR,
+               DM_VERSION_MINOR, DM_VERSION_PATCHLEVEL, DM_VERSION_EXTRA,
+               DM_DRIVER_EMAIL);
+        return 0;
+}
+
+void dm_interface_exit(void)
+{
+        if (misc_deregister(&_dm_misc) < 0)
+                DMERR("misc_deregister failed for control device");
+
+        dm_hash_exit();
+}