1 files changed, 696 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 0000000..e69b965
--- /dev/null
+++ b/drivers/md/dm-log-userspace-base.c
@@ -0,0 +1,696 @@
+/*
+ * Copyright (C) 2006-2009 Red Hat, Inc.
+ *
+ * This file is released under the LGPL.
+ */
+
+#include <linux/bio.h>
+#include <linux/dm-dirty-log.h>
+#include <linux/device-mapper.h>
+#include <linux/dm-log-userspace.h>
+
+#include "dm-log-userspace-transfer.h"
+
+struct flush_entry {
+	int type;
+	region_t region;
+	struct list_head list;
+};
+
+struct log_c {
+	struct dm_target *ti;
+	uint32_t region_size;
+	region_t region_count;
+	char uuid[DM_UUID_LEN];
+
+	char *usr_argv_str;
+	uint32_t usr_argc;
+
+	/*
+	 * 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;
+
+	spinlock_t flush_lock;
+	struct list_head flush_list;  /* only for clear and mark requests */
+};
+
+static mempool_t *flush_entry_pool;
+
+static void *flush_entry_alloc(gfp_t gfp_mask, void *pool_data)
+{
+	return kmalloc(sizeof(struct flush_entry), gfp_mask);
+}
+
+static void flush_entry_free(void *element, void *pool_data)
+{
+	kfree(element);
+}
+
+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, 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, 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, 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;
+
+	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;
+	}
+
+	for (i = 0, str_size = 0; i < argc; i++)
+		str_size += sprintf(str + str_size, "%s ", argv[i]);
+	str_size += sprintf(str + str_size, "%llu",
+			    (unsigned long long)ti->len);
+
+	*ctr_str = str;
+	return str_size;
+}
+
+/*
+ * userspace_ctr
+ *
+ * argv contains:
+ *	<UUID> <other args>
+ * Where 'other args' is the userspace implementation specific log
+ * arguments.  An example might be:
+ *	<UUID> clustered_disk <arg count> <log dev> <region_size> [[no]sync]
+ *
+ * So, this module will strip off the <UUID> for identification purposes
+ * when communicating with userspace about a log; but will pass on everything
+ * else.
+ */
+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);
+
+	if (argc < 3) {
+		DMWARN("Too few arguments to userspace dirty log");
+		return -EINVAL;
+	}
+
+	lc = kmalloc(sizeof(*lc), GFP_KERNEL);
+	if (!lc) {
+		DMWARN("Unable to allocate userspace log context.");
+		return -ENOMEM;
+	}
+
+	lc->ti = ti;
+
+	if (strlen(argv[0]) > (DM_UUID_LEN - 1)) {
+		DMWARN("UUID argument too long.");
+		kfree(lc);
+		return -EINVAL;
+	}
+
+	strncpy(lc->uuid, argv[0], DM_UUID_LEN);
+	spin_lock_init(&lc->flush_lock);
+	INIT_LIST_HEAD(&lc->flush_list);
+
+	str_size = build_constructor_string(ti, argc - 1, argv + 1, &ctr_str);
+	if (str_size < 0) {
+		kfree(lc);
+		return str_size;
+	}
+
+	/* Send table string */
+	r = dm_consult_userspace(lc->uuid, DM_ULOG_CTR,
+				 ctr_str, str_size, NULL, NULL);
+
+	if (r == -ESRCH) {
+		DMERR("Userspace log server not found");
+		goto out;
+	}
+
+	/* Since the region size does not change, get it now */
+	rdata_size = sizeof(rdata);
+	r = dm_consult_userspace(lc->uuid, 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);
+
+out:
+	if (r) {
+		kfree(lc);
+		kfree(ctr_str);
+	} else {
+		lc->usr_argv_str = ctr_str;
+		lc->usr_argc = argc;
+		log->context = lc;
+	}
+
+	return r;
+}
+
+static void userspace_dtr(struct dm_dirty_log *log)
+{
+	int r;
+	struct log_c *lc = log->context;
+
+	r = dm_consult_userspace(lc->uuid, DM_ULOG_DTR,
+				 NULL, 0,
+				 NULL, NULL);
+
+	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, 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;
+
+	r = dm_consult_userspace(lc->uuid, 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, 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;
+}
+
+/*
+ * 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(flush_list);
+	struct flush_entry *fe, *tmp_fe;
+
+	spin_lock_irqsave(&lc->flush_lock, flags);
+	list_splice_init(&lc->flush_list, &flush_list);
+	spin_unlock_irqrestore(&lc->flush_lock, flags);
+
+	if (list_empty(&flush_list))
+		return 0;
+
+	/*
+	 * FIXME: Count up requests, group request types,
+	 * allocate memory to stick all requests in and
+	 * send to server in one go.  Failing the allocation,
+	 * do it one by one.
+	 */
+
+	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)
+			goto fail;
+	}
+
+	r = userspace_do_request(lc, lc->uuid, DM_ULOG_FLUSH,
+				 NULL, 0, NULL, NULL);
+
+fail:
+	/*
+	 * We can safely remove these entries, even if failure.
+	 * Calling code will receive an error and will know that
+	 * the log facility has failed.
+	 */
+	list_for_each_entry_safe(fe, tmp_fe, &flush_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 flush_entry *fe;
+
+	/* Wait for an allocation, but _never_ fail */
+	fe = mempool_alloc(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->flush_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 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(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->flush_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)
+{
+	int r;
+	struct log_c *lc = log->context;
+	struct {
+		region_t r;
+		int64_t i;
+	} pkg;
+
+	pkg.r = region;
+	pkg.i = (int64_t)in_sync;
+
+	r = 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 emough 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;
+	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;
+		DMEMIT("%s %u %s %s", log->type->name, lc->usr_argc + 1,
+		       lc->uuid, lc->usr_argv_str);
+		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 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 (jiffies < limit)
+		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_pool = mempool_create(100, flush_entry_alloc,
+					  flush_entry_free, NULL);
+
+	if (!flush_entry_pool) {
+		DMWARN("Unable to create flush_entry_pool:  No memory.");
+		return -ENOMEM;
+	}
+
+	r = dm_ulog_tfr_init();
+	if (r) {
+		DMWARN("Unable to initialize userspace log communications");
+		mempool_destroy(flush_entry_pool);
+		return r;
+	}
+
+	r = dm_dirty_log_type_register(&_userspace_type);
+	if (r) {
+		DMWARN("Couldn't register userspace dirty log type");
+		dm_ulog_tfr_exit();
+		mempool_destroy(flush_entry_pool);
+		return r;
+	}
+
+	DMINFO("version 1.0.0 loaded");
+	return 0;
+}
+
+static void __exit userspace_dirty_log_exit(void)
+{
+	dm_dirty_log_type_unregister(&_userspace_type);
+	dm_ulog_tfr_exit();
+	mempool_destroy(flush_entry_pool);
+
+	DMINFO("version 1.0.0 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");