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path: root/drivers/md/dm-log-userspace-base.c
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Diffstat (limited to 'drivers/md/dm-log-userspace-base.c')
-rw-r--r--drivers/md/dm-log-userspace-base.c936
1 files changed, 936 insertions, 0 deletions
diff --git a/drivers/md/dm-log-userspace-base.c b/drivers/md/dm-log-userspace-base.c
new file mode 100644
index 000000000..058256d2e
--- /dev/null
+++ b/drivers/md/dm-log-userspace-base.c
@@ -0,0 +1,936 @@
+/*
+ * Copyright (C) 2006-2009 Red Hat, Inc.
+ *
+ * This file is released under the LGPL.
+ */
+
+#include <linux/bio.h>
+#include <linux/slab.h>
+#include <linux/jiffies.h>
+#include <linux/dm-dirty-log.h>
+#include <linux/device-mapper.h>
+#include <linux/dm-log-userspace.h>
+#include <linux/module.h>
+#include <linux/workqueue.h>
+
+#include "dm-log-userspace-transfer.h"
+
+#define DM_LOG_USERSPACE_VSN "1.3.0"
+
+#define FLUSH_ENTRY_POOL_SIZE 16
+
+struct dm_dirty_log_flush_entry {
+ int type;
+ region_t region;
+ struct list_head list;
+};
+
+/*
+ * This limit on the number of mark and clear request is, to a degree,
+ * arbitrary. However, there is some basis for the choice in the limits
+ * imposed on the size of data payload by dm-log-userspace-transfer.c:
+ * dm_consult_userspace().
+ */
+#define MAX_FLUSH_GROUP_COUNT 32
+
+struct log_c {
+ struct dm_target *ti;
+ struct dm_dev *log_dev;
+
+ char *usr_argv_str;
+ uint32_t usr_argc;
+
+ uint32_t region_size;
+ region_t region_count;
+ uint64_t luid;
+ char uuid[DM_UUID_LEN];
+
+ /*
+ * Mark and clear requests are held until a flush is issued
+ * so that we can group, and thereby limit, the amount of
+ * network traffic between kernel and userspace. The 'flush_lock'
+ * is used to protect these lists.
+ */
+ spinlock_t flush_lock;
+ struct list_head mark_list;
+ struct list_head clear_list;
+
+ /*
+ * in_sync_hint gets set when doing is_remote_recovering. It
+ * represents the first region that needs recovery. IOW, the
+ * first zero bit of sync_bits. This can be useful for to limit
+ * traffic for calls like is_remote_recovering and get_resync_work,
+ * but be take care in its use for anything else.
+ */
+ uint64_t in_sync_hint;
+
+ /*
+ * Workqueue for flush of clear region requests.
+ */
+ struct workqueue_struct *dmlog_wq;
+ struct delayed_work flush_log_work;
+ atomic_t sched_flush;
+
+ /*
+ * Combine userspace flush and mark requests for efficiency.
+ */
+ uint32_t integrated_flush;
+
+ mempool_t *flush_entry_pool;
+};
+
+static struct kmem_cache *_flush_entry_cache;
+
+static int userspace_do_request(struct log_c *lc, const char *uuid,
+ int request_type, char *data, size_t data_size,
+ char *rdata, size_t *rdata_size)
+{
+ int r;
+
+ /*
+ * If the server isn't there, -ESRCH is returned,
+ * and we must keep trying until the server is
+ * restored.
+ */
+retry:
+ r = dm_consult_userspace(uuid, lc->luid, request_type, data,
+ data_size, rdata, rdata_size);
+
+ if (r != -ESRCH)
+ return r;
+
+ DMERR(" Userspace log server not found.");
+ while (1) {
+ set_current_state(TASK_INTERRUPTIBLE);
+ schedule_timeout(2*HZ);
+ DMWARN("Attempting to contact userspace log server...");
+ r = dm_consult_userspace(uuid, lc->luid, DM_ULOG_CTR,
+ lc->usr_argv_str,
+ strlen(lc->usr_argv_str) + 1,
+ NULL, NULL);
+ if (!r)
+ break;
+ }
+ DMINFO("Reconnected to userspace log server... DM_ULOG_CTR complete");
+ r = dm_consult_userspace(uuid, lc->luid, DM_ULOG_RESUME, NULL,
+ 0, NULL, NULL);
+ if (!r)
+ goto retry;
+
+ DMERR("Error trying to resume userspace log: %d", r);
+
+ return -ESRCH;
+}
+
+static int build_constructor_string(struct dm_target *ti,
+ unsigned argc, char **argv,
+ char **ctr_str)
+{
+ int i, str_size;
+ char *str = NULL;
+
+ *ctr_str = NULL;
+
+ /*
+ * Determine overall size of the string.
+ */
+ for (i = 0, str_size = 0; i < argc; i++)
+ str_size += strlen(argv[i]) + 1; /* +1 for space between args */
+
+ str_size += 20; /* Max number of chars in a printed u64 number */
+
+ str = kzalloc(str_size, GFP_KERNEL);
+ if (!str) {
+ DMWARN("Unable to allocate memory for constructor string");
+ return -ENOMEM;
+ }
+
+ str_size = sprintf(str, "%llu", (unsigned long long)ti->len);
+ for (i = 0; i < argc; i++)
+ str_size += sprintf(str + str_size, " %s", argv[i]);
+
+ *ctr_str = str;
+ return str_size;
+}
+
+static void do_flush(struct work_struct *work)
+{
+ int r;
+ struct log_c *lc = container_of(work, struct log_c, flush_log_work.work);
+
+ atomic_set(&lc->sched_flush, 0);
+
+ r = userspace_do_request(lc, lc->uuid, DM_ULOG_FLUSH, NULL, 0, NULL, NULL);
+
+ if (r)
+ dm_table_event(lc->ti->table);
+}
+
+/*
+ * userspace_ctr
+ *
+ * argv contains:
+ * <UUID> [integrated_flush] <other args>
+ * Where 'other args' are the userspace implementation-specific log
+ * arguments.
+ *
+ * Example:
+ * <UUID> [integrated_flush] clustered-disk <arg count> <log dev>
+ * <region_size> [[no]sync]
+ *
+ * This module strips off the <UUID> and uses it for identification
+ * purposes when communicating with userspace about a log.
+ *
+ * If integrated_flush is defined, the kernel combines flush
+ * and mark requests.
+ *
+ * The rest of the line, beginning with 'clustered-disk', is passed
+ * to the userspace ctr function.
+ */
+static int userspace_ctr(struct dm_dirty_log *log, struct dm_target *ti,
+ unsigned argc, char **argv)
+{
+ int r = 0;
+ int str_size;
+ char *ctr_str = NULL;
+ struct log_c *lc = NULL;
+ uint64_t rdata;
+ size_t rdata_size = sizeof(rdata);
+ char *devices_rdata = NULL;
+ size_t devices_rdata_size = DM_NAME_LEN;
+
+ if (argc < 3) {
+ DMWARN("Too few arguments to userspace dirty log");
+ return -EINVAL;
+ }
+
+ lc = kzalloc(sizeof(*lc), GFP_KERNEL);
+ if (!lc) {
+ DMWARN("Unable to allocate userspace log context.");
+ return -ENOMEM;
+ }
+
+ /* The ptr value is sufficient for local unique id */
+ lc->luid = (unsigned long)lc;
+
+ lc->ti = ti;
+
+ if (strlen(argv[0]) > (DM_UUID_LEN - 1)) {
+ DMWARN("UUID argument too long.");
+ kfree(lc);
+ return -EINVAL;
+ }
+
+ lc->usr_argc = argc;
+
+ strncpy(lc->uuid, argv[0], DM_UUID_LEN);
+ argc--;
+ argv++;
+ spin_lock_init(&lc->flush_lock);
+ INIT_LIST_HEAD(&lc->mark_list);
+ INIT_LIST_HEAD(&lc->clear_list);
+
+ if (!strcasecmp(argv[0], "integrated_flush")) {
+ lc->integrated_flush = 1;
+ argc--;
+ argv++;
+ }
+
+ str_size = build_constructor_string(ti, argc, argv, &ctr_str);
+ if (str_size < 0) {
+ kfree(lc);
+ return str_size;
+ }
+
+ devices_rdata = kzalloc(devices_rdata_size, GFP_KERNEL);
+ if (!devices_rdata) {
+ DMERR("Failed to allocate memory for device information");
+ r = -ENOMEM;
+ goto out;
+ }
+
+ lc->flush_entry_pool = mempool_create_slab_pool(FLUSH_ENTRY_POOL_SIZE,
+ _flush_entry_cache);
+ if (!lc->flush_entry_pool) {
+ DMERR("Failed to create flush_entry_pool");
+ r = -ENOMEM;
+ goto out;
+ }
+
+ /*
+ * Send table string and get back any opened device.
+ */
+ r = dm_consult_userspace(lc->uuid, lc->luid, DM_ULOG_CTR,
+ ctr_str, str_size,
+ devices_rdata, &devices_rdata_size);
+
+ if (r < 0) {
+ if (r == -ESRCH)
+ DMERR("Userspace log server not found");
+ else
+ DMERR("Userspace log server failed to create log");
+ goto out;
+ }
+
+ /* Since the region size does not change, get it now */
+ rdata_size = sizeof(rdata);
+ r = dm_consult_userspace(lc->uuid, lc->luid, DM_ULOG_GET_REGION_SIZE,
+ NULL, 0, (char *)&rdata, &rdata_size);
+
+ if (r) {
+ DMERR("Failed to get region size of dirty log");
+ goto out;
+ }
+
+ lc->region_size = (uint32_t)rdata;
+ lc->region_count = dm_sector_div_up(ti->len, lc->region_size);
+
+ if (devices_rdata_size) {
+ if (devices_rdata[devices_rdata_size - 1] != '\0') {
+ DMERR("DM_ULOG_CTR device return string not properly terminated");
+ r = -EINVAL;
+ goto out;
+ }
+ r = dm_get_device(ti, devices_rdata,
+ dm_table_get_mode(ti->table), &lc->log_dev);
+ if (r)
+ DMERR("Failed to register %s with device-mapper",
+ devices_rdata);
+ }
+
+ if (lc->integrated_flush) {
+ lc->dmlog_wq = alloc_workqueue("dmlogd", WQ_MEM_RECLAIM, 0);
+ if (!lc->dmlog_wq) {
+ DMERR("couldn't start dmlogd");
+ r = -ENOMEM;
+ goto out;
+ }
+
+ INIT_DELAYED_WORK(&lc->flush_log_work, do_flush);
+ atomic_set(&lc->sched_flush, 0);
+ }
+
+out:
+ kfree(devices_rdata);
+ if (r) {
+ if (lc->flush_entry_pool)
+ mempool_destroy(lc->flush_entry_pool);
+ kfree(lc);
+ kfree(ctr_str);
+ } else {
+ lc->usr_argv_str = ctr_str;
+ log->context = lc;
+ }
+
+ return r;
+}
+
+static void userspace_dtr(struct dm_dirty_log *log)
+{
+ struct log_c *lc = log->context;
+
+ if (lc->integrated_flush) {
+ /* flush workqueue */
+ if (atomic_read(&lc->sched_flush))
+ flush_delayed_work(&lc->flush_log_work);
+
+ destroy_workqueue(lc->dmlog_wq);
+ }
+
+ (void) dm_consult_userspace(lc->uuid, lc->luid, DM_ULOG_DTR,
+ NULL, 0, NULL, NULL);
+
+ if (lc->log_dev)
+ dm_put_device(lc->ti, lc->log_dev);
+
+ mempool_destroy(lc->flush_entry_pool);
+
+ kfree(lc->usr_argv_str);
+ kfree(lc);
+
+ return;
+}
+
+static int userspace_presuspend(struct dm_dirty_log *log)
+{
+ int r;
+ struct log_c *lc = log->context;
+
+ r = dm_consult_userspace(lc->uuid, lc->luid, DM_ULOG_PRESUSPEND,
+ NULL, 0, NULL, NULL);
+
+ return r;
+}
+
+static int userspace_postsuspend(struct dm_dirty_log *log)
+{
+ int r;
+ struct log_c *lc = log->context;
+
+ /*
+ * Run planned flush earlier.
+ */
+ if (lc->integrated_flush && atomic_read(&lc->sched_flush))
+ flush_delayed_work(&lc->flush_log_work);
+
+ r = dm_consult_userspace(lc->uuid, lc->luid, DM_ULOG_POSTSUSPEND,
+ NULL, 0, NULL, NULL);
+
+ return r;
+}
+
+static int userspace_resume(struct dm_dirty_log *log)
+{
+ int r;
+ struct log_c *lc = log->context;
+
+ lc->in_sync_hint = 0;
+ r = dm_consult_userspace(lc->uuid, lc->luid, DM_ULOG_RESUME,
+ NULL, 0, NULL, NULL);
+
+ return r;
+}
+
+static uint32_t userspace_get_region_size(struct dm_dirty_log *log)
+{
+ struct log_c *lc = log->context;
+
+ return lc->region_size;
+}
+
+/*
+ * userspace_is_clean
+ *
+ * Check whether a region is clean. If there is any sort of
+ * failure when consulting the server, we return not clean.
+ *
+ * Returns: 1 if clean, 0 otherwise
+ */
+static int userspace_is_clean(struct dm_dirty_log *log, region_t region)
+{
+ int r;
+ uint64_t region64 = (uint64_t)region;
+ int64_t is_clean;
+ size_t rdata_size;
+ struct log_c *lc = log->context;
+
+ rdata_size = sizeof(is_clean);
+ r = userspace_do_request(lc, lc->uuid, DM_ULOG_IS_CLEAN,
+ (char *)&region64, sizeof(region64),
+ (char *)&is_clean, &rdata_size);
+
+ return (r) ? 0 : (int)is_clean;
+}
+
+/*
+ * userspace_in_sync
+ *
+ * Check if the region is in-sync. If there is any sort
+ * of failure when consulting the server, we assume that
+ * the region is not in sync.
+ *
+ * If 'can_block' is set, return immediately
+ *
+ * Returns: 1 if in-sync, 0 if not-in-sync, -EWOULDBLOCK
+ */
+static int userspace_in_sync(struct dm_dirty_log *log, region_t region,
+ int can_block)
+{
+ int r;
+ uint64_t region64 = region;
+ int64_t in_sync;
+ size_t rdata_size;
+ struct log_c *lc = log->context;
+
+ /*
+ * We can never respond directly - even if in_sync_hint is
+ * set. This is because another machine could see a device
+ * failure and mark the region out-of-sync. If we don't go
+ * to userspace to ask, we might think the region is in-sync
+ * and allow a read to pick up data that is stale. (This is
+ * very unlikely if a device actually fails; but it is very
+ * likely if a connection to one device from one machine fails.)
+ *
+ * There still might be a problem if the mirror caches the region
+ * state as in-sync... but then this call would not be made. So,
+ * that is a mirror problem.
+ */
+ if (!can_block)
+ return -EWOULDBLOCK;
+
+ rdata_size = sizeof(in_sync);
+ r = userspace_do_request(lc, lc->uuid, DM_ULOG_IN_SYNC,
+ (char *)&region64, sizeof(region64),
+ (char *)&in_sync, &rdata_size);
+ return (r) ? 0 : (int)in_sync;
+}
+
+static int flush_one_by_one(struct log_c *lc, struct list_head *flush_list)
+{
+ int r = 0;
+ struct dm_dirty_log_flush_entry *fe;
+
+ list_for_each_entry(fe, flush_list, list) {
+ r = userspace_do_request(lc, lc->uuid, fe->type,
+ (char *)&fe->region,
+ sizeof(fe->region),
+ NULL, NULL);
+ if (r)
+ break;
+ }
+
+ return r;
+}
+
+static int flush_by_group(struct log_c *lc, struct list_head *flush_list,
+ int flush_with_payload)
+{
+ int r = 0;
+ int count;
+ uint32_t type = 0;
+ struct dm_dirty_log_flush_entry *fe, *tmp_fe;
+ LIST_HEAD(tmp_list);
+ uint64_t group[MAX_FLUSH_GROUP_COUNT];
+
+ /*
+ * Group process the requests
+ */
+ while (!list_empty(flush_list)) {
+ count = 0;
+
+ list_for_each_entry_safe(fe, tmp_fe, flush_list, list) {
+ group[count] = fe->region;
+ count++;
+
+ list_move(&fe->list, &tmp_list);
+
+ type = fe->type;
+ if (count >= MAX_FLUSH_GROUP_COUNT)
+ break;
+ }
+
+ if (flush_with_payload) {
+ r = userspace_do_request(lc, lc->uuid, DM_ULOG_FLUSH,
+ (char *)(group),
+ count * sizeof(uint64_t),
+ NULL, NULL);
+ /*
+ * Integrated flush failed.
+ */
+ if (r)
+ break;
+ } else {
+ r = userspace_do_request(lc, lc->uuid, type,
+ (char *)(group),
+ count * sizeof(uint64_t),
+ NULL, NULL);
+ if (r) {
+ /*
+ * Group send failed. Attempt one-by-one.
+ */
+ list_splice_init(&tmp_list, flush_list);
+ r = flush_one_by_one(lc, flush_list);
+ break;
+ }
+ }
+ }
+
+ /*
+ * Must collect flush_entrys that were successfully processed
+ * as a group so that they will be free'd by the caller.
+ */
+ list_splice_init(&tmp_list, flush_list);
+
+ return r;
+}
+
+/*
+ * userspace_flush
+ *
+ * This function is ok to block.
+ * The flush happens in two stages. First, it sends all
+ * clear/mark requests that are on the list. Then it
+ * tells the server to commit them. This gives the
+ * server a chance to optimise the commit, instead of
+ * doing it for every request.
+ *
+ * Additionally, we could implement another thread that
+ * sends the requests up to the server - reducing the
+ * load on flush. Then the flush would have less in
+ * the list and be responsible for the finishing commit.
+ *
+ * Returns: 0 on success, < 0 on failure
+ */
+static int userspace_flush(struct dm_dirty_log *log)
+{
+ int r = 0;
+ unsigned long flags;
+ struct log_c *lc = log->context;
+ LIST_HEAD(mark_list);
+ LIST_HEAD(clear_list);
+ int mark_list_is_empty;
+ int clear_list_is_empty;
+ struct dm_dirty_log_flush_entry *fe, *tmp_fe;
+ mempool_t *flush_entry_pool = lc->flush_entry_pool;
+
+ spin_lock_irqsave(&lc->flush_lock, flags);
+ list_splice_init(&lc->mark_list, &mark_list);
+ list_splice_init(&lc->clear_list, &clear_list);
+ spin_unlock_irqrestore(&lc->flush_lock, flags);
+
+ mark_list_is_empty = list_empty(&mark_list);
+ clear_list_is_empty = list_empty(&clear_list);
+
+ if (mark_list_is_empty && clear_list_is_empty)
+ return 0;
+
+ r = flush_by_group(lc, &clear_list, 0);
+ if (r)
+ goto out;
+
+ if (!lc->integrated_flush) {
+ r = flush_by_group(lc, &mark_list, 0);
+ if (r)
+ goto out;
+ r = userspace_do_request(lc, lc->uuid, DM_ULOG_FLUSH,
+ NULL, 0, NULL, NULL);
+ goto out;
+ }
+
+ /*
+ * Send integrated flush request with mark_list as payload.
+ */
+ r = flush_by_group(lc, &mark_list, 1);
+ if (r)
+ goto out;
+
+ if (mark_list_is_empty && !atomic_read(&lc->sched_flush)) {
+ /*
+ * When there are only clear region requests,
+ * we schedule a flush in the future.
+ */
+ queue_delayed_work(lc->dmlog_wq, &lc->flush_log_work, 3 * HZ);
+ atomic_set(&lc->sched_flush, 1);
+ } else {
+ /*
+ * Cancel pending flush because we
+ * have already flushed in mark_region.
+ */
+ cancel_delayed_work(&lc->flush_log_work);
+ atomic_set(&lc->sched_flush, 0);
+ }
+
+out:
+ /*
+ * We can safely remove these entries, even after failure.
+ * Calling code will receive an error and will know that
+ * the log facility has failed.
+ */
+ list_for_each_entry_safe(fe, tmp_fe, &mark_list, list) {
+ list_del(&fe->list);
+ mempool_free(fe, flush_entry_pool);
+ }
+ list_for_each_entry_safe(fe, tmp_fe, &clear_list, list) {
+ list_del(&fe->list);
+ mempool_free(fe, flush_entry_pool);
+ }
+
+ if (r)
+ dm_table_event(lc->ti->table);
+
+ return r;
+}
+
+/*
+ * userspace_mark_region
+ *
+ * This function should avoid blocking unless absolutely required.
+ * (Memory allocation is valid for blocking.)
+ */
+static void userspace_mark_region(struct dm_dirty_log *log, region_t region)
+{
+ unsigned long flags;
+ struct log_c *lc = log->context;
+ struct dm_dirty_log_flush_entry *fe;
+
+ /* Wait for an allocation, but _never_ fail */
+ fe = mempool_alloc(lc->flush_entry_pool, GFP_NOIO);
+ BUG_ON(!fe);
+
+ spin_lock_irqsave(&lc->flush_lock, flags);
+ fe->type = DM_ULOG_MARK_REGION;
+ fe->region = region;
+ list_add(&fe->list, &lc->mark_list);
+ spin_unlock_irqrestore(&lc->flush_lock, flags);
+
+ return;
+}
+
+/*
+ * userspace_clear_region
+ *
+ * This function must not block.
+ * So, the alloc can't block. In the worst case, it is ok to
+ * fail. It would simply mean we can't clear the region.
+ * Does nothing to current sync context, but does mean
+ * the region will be re-sync'ed on a reload of the mirror
+ * even though it is in-sync.
+ */
+static void userspace_clear_region(struct dm_dirty_log *log, region_t region)
+{
+ unsigned long flags;
+ struct log_c *lc = log->context;
+ struct dm_dirty_log_flush_entry *fe;
+
+ /*
+ * If we fail to allocate, we skip the clearing of
+ * the region. This doesn't hurt us in any way, except
+ * to cause the region to be resync'ed when the
+ * device is activated next time.
+ */
+ fe = mempool_alloc(lc->flush_entry_pool, GFP_ATOMIC);
+ if (!fe) {
+ DMERR("Failed to allocate memory to clear region.");
+ return;
+ }
+
+ spin_lock_irqsave(&lc->flush_lock, flags);
+ fe->type = DM_ULOG_CLEAR_REGION;
+ fe->region = region;
+ list_add(&fe->list, &lc->clear_list);
+ spin_unlock_irqrestore(&lc->flush_lock, flags);
+
+ return;
+}
+
+/*
+ * userspace_get_resync_work
+ *
+ * Get a region that needs recovery. It is valid to return
+ * an error for this function.
+ *
+ * Returns: 1 if region filled, 0 if no work, <0 on error
+ */
+static int userspace_get_resync_work(struct dm_dirty_log *log, region_t *region)
+{
+ int r;
+ size_t rdata_size;
+ struct log_c *lc = log->context;
+ struct {
+ int64_t i; /* 64-bit for mix arch compatibility */
+ region_t r;
+ } pkg;
+
+ if (lc->in_sync_hint >= lc->region_count)
+ return 0;
+
+ rdata_size = sizeof(pkg);
+ r = userspace_do_request(lc, lc->uuid, DM_ULOG_GET_RESYNC_WORK,
+ NULL, 0, (char *)&pkg, &rdata_size);
+
+ *region = pkg.r;
+ return (r) ? r : (int)pkg.i;
+}
+
+/*
+ * userspace_set_region_sync
+ *
+ * Set the sync status of a given region. This function
+ * must not fail.
+ */
+static void userspace_set_region_sync(struct dm_dirty_log *log,
+ region_t region, int in_sync)
+{
+ struct log_c *lc = log->context;
+ struct {
+ region_t r;
+ int64_t i;
+ } pkg;
+
+ pkg.r = region;
+ pkg.i = (int64_t)in_sync;
+
+ (void) userspace_do_request(lc, lc->uuid, DM_ULOG_SET_REGION_SYNC,
+ (char *)&pkg, sizeof(pkg), NULL, NULL);
+
+ /*
+ * It would be nice to be able to report failures.
+ * However, it is easy enough to detect and resolve.
+ */
+ return;
+}
+
+/*
+ * userspace_get_sync_count
+ *
+ * If there is any sort of failure when consulting the server,
+ * we assume that the sync count is zero.
+ *
+ * Returns: sync count on success, 0 on failure
+ */
+static region_t userspace_get_sync_count(struct dm_dirty_log *log)
+{
+ int r;
+ size_t rdata_size;
+ uint64_t sync_count;
+ struct log_c *lc = log->context;
+
+ rdata_size = sizeof(sync_count);
+ r = userspace_do_request(lc, lc->uuid, DM_ULOG_GET_SYNC_COUNT,
+ NULL, 0, (char *)&sync_count, &rdata_size);
+
+ if (r)
+ return 0;
+
+ if (sync_count >= lc->region_count)
+ lc->in_sync_hint = lc->region_count;
+
+ return (region_t)sync_count;
+}
+
+/*
+ * userspace_status
+ *
+ * Returns: amount of space consumed
+ */
+static int userspace_status(struct dm_dirty_log *log, status_type_t status_type,
+ char *result, unsigned maxlen)
+{
+ int r = 0;
+ char *table_args;
+ size_t sz = (size_t)maxlen;
+ struct log_c *lc = log->context;
+
+ switch (status_type) {
+ case STATUSTYPE_INFO:
+ r = userspace_do_request(lc, lc->uuid, DM_ULOG_STATUS_INFO,
+ NULL, 0, result, &sz);
+
+ if (r) {
+ sz = 0;
+ DMEMIT("%s 1 COM_FAILURE", log->type->name);
+ }
+ break;
+ case STATUSTYPE_TABLE:
+ sz = 0;
+ table_args = strchr(lc->usr_argv_str, ' ');
+ BUG_ON(!table_args); /* There will always be a ' ' */
+ table_args++;
+
+ DMEMIT("%s %u %s ", log->type->name, lc->usr_argc, lc->uuid);
+ if (lc->integrated_flush)
+ DMEMIT("integrated_flush ");
+ DMEMIT("%s ", table_args);
+ break;
+ }
+ return (r) ? 0 : (int)sz;
+}
+
+/*
+ * userspace_is_remote_recovering
+ *
+ * Returns: 1 if region recovering, 0 otherwise
+ */
+static int userspace_is_remote_recovering(struct dm_dirty_log *log,
+ region_t region)
+{
+ int r;
+ uint64_t region64 = region;
+ struct log_c *lc = log->context;
+ static unsigned long limit;
+ struct {
+ int64_t is_recovering;
+ uint64_t in_sync_hint;
+ } pkg;
+ size_t rdata_size = sizeof(pkg);
+
+ /*
+ * Once the mirror has been reported to be in-sync,
+ * it will never again ask for recovery work. So,
+ * we can safely say there is not a remote machine
+ * recovering if the device is in-sync. (in_sync_hint
+ * must be reset at resume time.)
+ */
+ if (region < lc->in_sync_hint)
+ return 0;
+ else if (time_after(limit, jiffies))
+ return 1;
+
+ limit = jiffies + (HZ / 4);
+ r = userspace_do_request(lc, lc->uuid, DM_ULOG_IS_REMOTE_RECOVERING,
+ (char *)&region64, sizeof(region64),
+ (char *)&pkg, &rdata_size);
+ if (r)
+ return 1;
+
+ lc->in_sync_hint = pkg.in_sync_hint;
+
+ return (int)pkg.is_recovering;
+}
+
+static struct dm_dirty_log_type _userspace_type = {
+ .name = "userspace",
+ .module = THIS_MODULE,
+ .ctr = userspace_ctr,
+ .dtr = userspace_dtr,
+ .presuspend = userspace_presuspend,
+ .postsuspend = userspace_postsuspend,
+ .resume = userspace_resume,
+ .get_region_size = userspace_get_region_size,
+ .is_clean = userspace_is_clean,
+ .in_sync = userspace_in_sync,
+ .flush = userspace_flush,
+ .mark_region = userspace_mark_region,
+ .clear_region = userspace_clear_region,
+ .get_resync_work = userspace_get_resync_work,
+ .set_region_sync = userspace_set_region_sync,
+ .get_sync_count = userspace_get_sync_count,
+ .status = userspace_status,
+ .is_remote_recovering = userspace_is_remote_recovering,
+};
+
+static int __init userspace_dirty_log_init(void)
+{
+ int r = 0;
+
+ _flush_entry_cache = KMEM_CACHE(dm_dirty_log_flush_entry, 0);
+ if (!_flush_entry_cache) {
+ DMWARN("Unable to create flush_entry_cache: No memory.");
+ return -ENOMEM;
+ }
+
+ r = dm_ulog_tfr_init();
+ if (r) {
+ DMWARN("Unable to initialize userspace log communications");
+ kmem_cache_destroy(_flush_entry_cache);
+ return r;
+ }
+
+ r = dm_dirty_log_type_register(&_userspace_type);
+ if (r) {
+ DMWARN("Couldn't register userspace dirty log type");
+ dm_ulog_tfr_exit();
+ kmem_cache_destroy(_flush_entry_cache);
+ return r;
+ }
+
+ DMINFO("version " DM_LOG_USERSPACE_VSN " loaded");
+ return 0;
+}
+
+static void __exit userspace_dirty_log_exit(void)
+{
+ dm_dirty_log_type_unregister(&_userspace_type);
+ dm_ulog_tfr_exit();
+ kmem_cache_destroy(_flush_entry_cache);
+
+ DMINFO("version " DM_LOG_USERSPACE_VSN " unloaded");
+ return;
+}
+
+module_init(userspace_dirty_log_init);
+module_exit(userspace_dirty_log_exit);
+
+MODULE_DESCRIPTION(DM_NAME " userspace dirty log link");
+MODULE_AUTHOR("Jonathan Brassow <dm-devel@redhat.com>");
+MODULE_LICENSE("GPL");