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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH 6 of 9] Remus tapdisk proxy
# HG changeset patch
# User Brendan Cully <brendan@xxxxxxxxx>
# Date 1240355510 25200
# Node ID 03fd0c9729f3d87e7803afb170dfc3cdff184998
# Parent 42fddb3a8edeb80339618b7f758dc2959cf97115
Remus tapdisk proxy.
This proxy forwards local disk writes to a backup server, where they are
buffered until the local disk receives a checkpoint signal from the remus
control tools, which it forwards to the backup to cause buffered writes
to be flushed.
Configuration is of the form
tap:remus:<backup host>:<backup port>:<underlying tapdisk string>
The first write to a disk protected by this proxy will block until the
Remus control tools have been activated, which create the backup
disk proxy.
Signed-off-by: Brendan Cully <brendan@xxxxxxxxx>
diff --git a/tools/blktap/drivers/Makefile b/tools/blktap/drivers/Makefile
--- a/tools/blktap/drivers/Makefile
+++ b/tools/blktap/drivers/Makefile
@@ -11,6 +11,8 @@
CFLAGS += $(CFLAGS_libxenctrl)
CFLAGS += $(CFLAGS_libxenstore)
CFLAGS += -I $(LIBAIO_DIR)
+# for hashtable_itr.h in gcc 4.2
+CFLAGS += -fgnu89-inline
CFLAGS += -D_GNU_SOURCE
ifeq ($(shell . ./check_gcrypt $(CC)),yes)
@@ -22,7 +24,8 @@
endif
LDFLAGS_blktapctrl := $(LDFLAGS_libxenctrl) $(LDFLAGS_libxenstore) -L../lib
-lblktap
-LDFLAGS_img := $(LIBAIO_DIR)/libaio.a $(CRYPT_LIB) -lpthread -lz
+# hashtable.c uses ceilf from libm
+LDFLAGS_img := $(LIBAIO_DIR)/libaio.a $(CRYPT_LIB) -lpthread -lm -lz
BLK-OBJS-y := block-aio.o
BLK-OBJS-y += block-sync.o
@@ -30,6 +33,7 @@
BLK-OBJS-y += block-ram.o
BLK-OBJS-y += block-qcow.o
BLK-OBJS-y += block-qcow2.o
+BLK-OBJS-y += block-remus.o hashtable.o hashtable_itr.o hashtable_utility.o
BLK-OBJS-y += aes.o
BLK-OBJS-y += tapaio.o
BLK-OBJS-$(CONFIG_Linux) += blk_linux.o
diff --git a/tools/blktap/drivers/block-remus.c
b/tools/blktap/drivers/block-remus.c
new file mode 100644
--- /dev/null
+++ b/tools/blktap/drivers/block-remus.c
@@ -0,0 +1,1686 @@
+/* block-remus.c
+ *
+ * This disk sends all writes to a backup via a network interface before
+ * passing them to an underlying device.
+ * The backup is a bit more complicated:
+ * 1. It applies all incoming writes to a ramdisk.
+ * 2. When a checkpoint request arrives, it moves the ramdisk to
+ * a committing state and uses a new ramdisk for subsequent writes.
+ * It also acknowledges the request, to let the sender know it can
+ * release output.
+ * 3. The ramdisk flushes its contents to the underlying driver.
+ * 4. At failover, the backup waits for the in-flight ramdisk (if any) to
+ * drain before letting the domain be activated.
+ *
+ * The driver determines whether it is the client or server by attempting
+ * to bind to the replication address. If the address is not local,
+ * the driver acts as client.
+ *
+ * The following messages are defined for the replication stream:
+ * 1. write request
+ * "wreq" 4
+ * num_sectors 4
+ * sector 8
+ * buffer (num_sectors * sector_size)
+ * 2. submit request (may be used as a barrier
+ * "sreq" 4
+ * 3. commit request
+ * "creq" 4
+ * After a commit request, the client must wait for a competion message:
+ * 4. completion
+ * "done" 4
+ */
+
+/* due to architectural choices in tapdisk, block-buffer is forced to
+ * reimplement some code which is meant to be private */
+#define TAPDISK
+#include "tapdisk.h"
+#include "hashtable.h"
+#include "hashtable_itr.h"
+#include "hashtable_utility.h"
+
+#include <errno.h>
+#include <inttypes.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/time.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netdb.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+#include <sys/param.h>
+#include <sys/sysctl.h>
+#include <unistd.h>
+
+/* timeout for reads and writes in ms */
+#define NET_TIMEOUT 500
+#define RAMDISK_HASHSIZE 128
+
+#define RPRINTF(_f, _a...) syslog (LOG_DEBUG, "remus: " _f, ## _a)
+
+enum tdremus_mode {
+ mode_pass = 0,
+ mode_client,
+ mode_server
+};
+
+struct tdremus_req {
+ uint64_t sector;
+ int nb_sectors;
+ char buf[4096];
+};
+
+struct req_ring {
+ /* waste one slot to distinguish between empty and full */
+ struct tdremus_req requests[MAX_REQUESTS * 2 + 1];
+ unsigned int head;
+ unsigned int tail;
+};
+
+struct ramdisk {
+ size_t sector_size;
+ struct hashtable* h;
+ /* when a ramdisk is flushed, h is given a new empty hash for writes
+ * while the old ramdisk (prev) is drained asynchronously. To avoid
+ * a race where a read request points to a sector in prev which has
+ * not yet been flushed, check prev on a miss in h */
+ struct hashtable* prev;
+ /* count of outstanding requests to the base driver */
+ size_t inflight;
+};
+
+/* the ramdisk intercepts the original callback for reads and writes.
+ * This holds the original data. */
+/* Might be worth making this a static array in struct ramdisk to avoid
+ * a malloc per request */
+
+struct tdremus_state;
+
+struct ramdisk_cbdata {
+ td_callback_t cb;
+ void* private;
+ char* buf;
+ struct tdremus_state* state;
+};
+
+struct ramdisk_write_cbdata {
+ struct tdremus_state* state;
+ char* buf;
+};
+
+typedef int (*queue_rw_t) (struct disk_driver *dd, uint64_t sector,
+ int nb_sectors, char *buf, td_callback_t cb,
+ int id, void *prv);
+
+struct tdremus_state {
+ struct tap_disk* driver;
+ void* driver_data;
+ char* path;
+
+ char* ctlfifo; /* receive flush instruction here */
+ int ctl_fd_idx; /* io_fd slot for control FIFO */
+ char* msgfifo; /* output completion message here */
+ int msgfd;
+
+ /* replication host */
+ struct in_addr addr;
+ unsigned short port;
+ int sfd; /* server listen port */
+ int rfd; /* replication channel */
+ int rfd_idx; /* io_fd slot for replication channel */
+
+ /* queue write requests, batch-replicate at submit */
+ struct req_ring write_ring;
+
+ /* ramdisk data*/
+ struct ramdisk ramdisk;
+
+ /* mode methods */
+ enum tdremus_mode mode;
+ queue_rw_t queue_read;
+ queue_rw_t queue_write;
+ int (*queue_flush)(struct disk_driver* dd);
+ int (*submit)(struct disk_driver* dd);
+ int (*queue_close)(struct disk_driver *dd);
+};
+
+static int tdremus_queue_read(struct disk_driver *dd, uint64_t sector,
+ int nb_sectors, char *buf, td_callback_t cb,
+ int id, void *private);
+static int tdremus_queue_write(struct disk_driver *dd, uint64_t sector,
+ int nb_sectors, char *buf, td_callback_t cb,
+ int id, void *private);
+static int tdremus_close(struct disk_driver *dd);
+
+/* ring functions */
+static inline unsigned int ring_next(struct req_ring* ring, unsigned int pos)
+{
+ if (++pos >= MAX_REQUESTS * 2 + 1)
+ return 0;
+
+ return pos;
+}
+
+static inline int ring_isempty(struct req_ring* ring)
+{
+ return ring->head == ring->tail;
+}
+
+static inline int ring_isfull(struct req_ring* ring)
+{
+ return ring_next(ring, ring->tail) == ring->head;
+}
+
+static int buf_queue_write(struct disk_driver *dd, uint64_t sector,
+ int nb_sectors, char *buf)
+{
+ struct tdremus_state *s = (struct tdremus_state *)dd->private;
+ struct tdremus_req* req;
+
+ /* queue requests until flush */
+ if (ring_isfull(&s->write_ring))
+ return -EBUSY;
+
+ req = s->write_ring.requests + s->write_ring.tail;
+ s->write_ring.tail = ring_next(&s->write_ring, s->write_ring.tail);
+
+ req->sector = sector;
+ req->nb_sectors = nb_sectors;
+ memcpy(req->buf, buf, req->nb_sectors * dd->td_state->sector_size);
+
+ return 0;
+}
+
+/* passthrough functions */
+
+static int pass_start(struct disk_driver* dd)
+{
+ struct tdremus_state *s = (struct tdremus_state *)dd->private;
+
+ s->queue_read = NULL;
+ s->queue_write = NULL;
+ s->submit = NULL;
+ s->queue_flush = NULL;
+ s->queue_close = NULL;
+
+ return 0;
+}
+
+/* ramdisk methods */
+static int ramdisk_flush(struct disk_driver* dd, struct tdremus_state *s);
+
+/* http://www.concentric.net/~Ttwang/tech/inthash.htm */
+static unsigned int uint64_hash(void* k)
+{
+ uint64_t key = *(uint64_t*)k;
+
+ key = (~key) + (key << 18);
+ key = key ^ (key >> 31);
+ key = key * 21;
+ key = key ^ (key >> 11);
+ key = key + (key << 6);
+ key = key ^ (key >> 22);
+
+ return (unsigned int)key;
+}
+
+static int rd_hash_equal(void* k1, void* k2)
+{
+ uint64_t key1, key2;
+
+ key1 = *(uint64_t*)k1;
+ key2 = *(uint64_t*)k2;
+
+ return key1 == key2;
+}
+
+static int ramdisk_read(struct ramdisk* ramdisk, uint64_t sector,
+ int nb_sectors, char* buf)
+{
+ int i;
+ char* v;
+ uint64_t key;
+
+ for (i = 0; i < nb_sectors; i++) {
+ key = sector + i;
+ if (!(v = hashtable_search(ramdisk->h, &key))) {
+ /* check whether it is queued in a previous flush request */
+ if (!(ramdisk->prev && (v = hashtable_search(ramdisk->prev, &key))))
+ return -1;
+ }
+ memcpy(buf + i * ramdisk->sector_size, v, ramdisk->sector_size);
+ }
+
+ return 0;
+}
+
+static int ramdisk_write_hash(struct hashtable* h, uint64_t sector, char* buf,
+ size_t len)
+{
+ char* v;
+ uint64_t* key;
+
+ if ((v = hashtable_search(h, §or))) {
+ memcpy(v, buf, len);
+ return 0;
+ }
+
+ if (!(v = malloc(len))) {
+ DPRINTF("ramdisk_write_hash: malloc failed\n");
+ return -1;
+ }
+ memcpy(v, buf, len);
+ if (!(key = malloc(sizeof(*key)))) {
+ DPRINTF("ramdisk_write_hash: error allocating key\n");
+ free(v);
+ return -1;
+ }
+ *key = sector;
+ if (!hashtable_insert(h, key, v)) {
+ DPRINTF("ramdisk_write_hash failed on sector %" PRIu64 "\n", sector);
+ free(key);
+ free(v);
+ return -1;
+ }
+
+ return 0;
+}
+
+static inline int ramdisk_write(struct ramdisk* ramdisk, uint64_t sector,
+ int nb_sectors, char* buf)
+{
+ int i, rc;
+
+ for (i = 0; i < nb_sectors; i++) {
+ rc = ramdisk_write_hash(ramdisk->h, sector + i,
+ buf + i * ramdisk->sector_size,
+ ramdisk->sector_size);
+ if (rc)
+ return rc;
+ }
+
+ return 0;
+}
+
+/* the underlying driver calls this callback instead of the original.
+ The result is applied to the ramdisk. Then the ramdisk version of the
+ data is returned via the original callback. */
+static int ramdisk_read_cb(struct disk_driver* dd, int res, uint64_t sector,
+ int nb_sectors, int id, void* private)
+{
+ struct ramdisk_cbdata *cbdata = (struct ramdisk_cbdata*)private;
+ struct tdremus_state *s = cbdata->state;
+ char* sectorbuf;
+ int rc;
+ int i;
+
+ if (!res) {
+ for (i = 0; i < nb_sectors; i++) {
+ sectorbuf = cbdata->buf + i * s->ramdisk.sector_size;
+ /* if data is in ramdisk, overwrite the buffer read with the ramdisk */
+ ramdisk_read(&s->ramdisk, sector + i, 1, sectorbuf);
+ /* else: should we cache the results? is that just a waste of RAM? */
+ }
+ }
+
+ rc = cbdata->cb(dd, res, sector, nb_sectors, id, cbdata->private);
+
+ free(cbdata);
+ return rc;
+}
+
+static int ramdisk_write_cb(struct disk_driver* dd, int res, uint64_t sector,
+ int nb_sectors, int id, void* private)
+{
+ struct ramdisk_write_cbdata *cbdata = (struct ramdisk_write_cbdata*)private;
+ struct tdremus_state *s = cbdata->state;
+ int rc;
+
+ /*
+ RPRINTF("ramdisk write callback: rc %d, %d sectors @ %llu\n", res,
nb_sectors,
+ sector);
+ */
+
+ free(cbdata->buf);
+ free(cbdata);
+
+ s->ramdisk.inflight--;
+ if (!s->ramdisk.inflight && !s->ramdisk.prev) {
+ /* when this reaches 0 and prev is empty, the disk is flushed. */
+ /*
+ RPRINTF("ramdisk flush complete\n");
+ */
+ }
+
+ if (s->ramdisk.prev) {
+ /* resubmit as much as possible in the remaining disk */
+ /*
+ RPRINTF("calling ramdisk_flush from write callback\n");
+ */
+ return ramdisk_flush(dd, s);
+ }
+
+ return 0;
+}
+
+static int ramdisk_queue_read(struct disk_driver *dd, uint64_t sector,
+ int nb_sectors, char *buf, td_callback_t cb,
+ int id, void *private)
+{
+ struct tdremus_state *s = (struct tdremus_state *)dd->private;
+ struct ramdisk_cbdata *cbdata;
+ int rc;
+
+ /* if block is present in ramdisk, return it. If any sectors are missing,
+ * fail and perform an overlay at the callback */
+ if (!(ramdisk_read(&s->ramdisk, sector, nb_sectors, buf)))
+ return cb(dd, 0, sector, nb_sectors, id, private);
+
+ /* otherwise queue a read to the underlying disk, with a new callback
+ * to fill the ramdisk */
+ if (!(cbdata = malloc(sizeof(*cbdata)))) {
+ DPRINTF("ramdisk_queue_read: Error allocating callback\n");
+ return -1;
+ }
+ cbdata->cb = cb;
+ cbdata->private = private;
+ cbdata->buf = buf;
+ /* callback may only have driver_data available */
+ cbdata->state = s;
+
+ dd->private = s->driver_data;
+ rc = s->driver->td_queue_read(dd, sector, nb_sectors, buf, ramdisk_read_cb,
+ id, cbdata);
+ dd->private = s;
+
+ return rc;
+}
+
+/* apply the write to the ramdisk directly. Wait until explicit flush
+ * to move to disk. Later we should probably trickle writes to the
+ * backup from here (not every call though). */
+static int ramdisk_queue_write(struct disk_driver *dd, uint64_t sector,
+ int nb_sectors, char *buf, td_callback_t cb,
+ int id, void *private)
+{
+ struct tdremus_state *s = (struct tdremus_state *)dd->private;
+ int rc;
+
+ /* write segment to ramdisk */
+ if ((rc = ramdisk_write(&s->ramdisk, sector, nb_sectors, buf))) {
+ DPRINTF("Ramdisk write failed: %d\n", rc);
+ return rc;
+ }
+
+ return cb(dd, 0, sector, nb_sectors, id, private);
+}
+
+static int uint64_compare(const void* k1, const void* k2)
+{
+ uint64_t u1 = *(uint64_t*)k1;
+ uint64_t u2 = *(uint64_t*)k2;
+
+ /* u1 - u2 is unsigned */
+ return u1 < u2 ? -1 : u1 > u2 ? 1 : 0;
+}
+
+/* set psectors to an array of the sector numbers in the hash, returning
+ * the number of entries (or -1 on error) */
+static int ramdisk_get_sectors(struct hashtable* h, uint64_t** psectors)
+{
+ struct hashtable_itr* itr;
+ uint64_t* sectors;
+ int count;
+
+ if (!(count = hashtable_count(h)))
+ return 0;
+
+ if (!(*psectors = malloc(count * sizeof(uint64_t)))) {
+ DPRINTF("ramdisk_get_sectors: error allocating sector map\n");
+ return -1;
+ }
+ sectors = *psectors;
+
+ itr = hashtable_iterator(h);
+ count = 0;
+ do {
+ sectors[count++] = *(uint64_t*)hashtable_iterator_key(itr);
+ } while (hashtable_iterator_advance(itr));
+ free(itr);
+
+ return count;
+}
+
+static char* merge_requests(struct ramdisk* ramdisk, uint64_t start,
+ size_t count)
+{
+ char* buf;
+ char* sector;
+ int i;
+
+ if (!(buf = valloc(count * ramdisk->sector_size))) {
+ DPRINTF("merge_request: allocation failed\n");
+ return NULL;
+ }
+
+ for (i = 0; i < count; i++) {
+ if (!(sector = hashtable_search(ramdisk->prev, &start))) {
+ DPRINTF("merge_request: lookup failed on %"PRIu64"\n", start);
+ return NULL;
+ }
+
+ memcpy(buf + i * ramdisk->sector_size, sector, ramdisk->sector_size);
+ free(sector);
+
+ start++;
+ }
+
+ return buf;
+}
+
+/* The underlying driver may not handle having the whole ramdisk queued at
+ * once. We queue what we can and let the callbacks attempt to queue more. */
+/* NOTE: may be called from callback, while dd->private still belongs to
+ * the underlying driver */
+static int ramdisk_flush(struct disk_driver* dd, struct tdremus_state* s)
+{
+ struct ramdisk_write_cbdata* cbdata;
+ uint64_t* sectors;
+ char* buf;
+ uint64_t base, batchlen;
+ int i, j, count = 0;
+
+ /*
+ RPRINTF("ramdisk flush\n");
+ */
+
+ if ((count = ramdisk_get_sectors(s->ramdisk.prev, §ors)) <= 0)
+ return count;
+
+ /*
+ RPRINTF("ramdisk: flushing %d sectors\n", count);
+ */
+
+ /* sort and merge sectors to improve disk performance */
+ qsort(sectors, count, sizeof(*sectors), uint64_compare);
+
+ for (i = 0; i < count;) {
+ if (!(cbdata = malloc(sizeof(*cbdata)))) {
+ RPRINTF("ramdisk_flush: error allocating cbdata\n");
+ free(sectors);
+ return -1;
+ }
+
+ base = sectors[i++];
+ while (i < count && sectors[i] == sectors[i-1] + 1)
+ i++;
+ batchlen = sectors[i-1] - base + 1;
+
+ if (!(buf = merge_requests(&s->ramdisk, base, batchlen))) {
+ RPRINTF("ramdisk_flush: merge_requests failed\n");
+ free(sectors);
+ return -1;
+ }
+
+ /* we probably want to record an ID for in-flight requests in ramdisk */
+ cbdata->state = s;
+ cbdata->buf = buf;
+
+ /*
+ RPRINTF("queuing write at %llu, length: %llu\n", base, batchlen);
+ */
+ dd->private = s->driver_data;
+ j = s->driver->td_queue_write(dd, base, batchlen, buf, ramdisk_write_cb,
+ 0, cbdata);
+ dd->private = s;
+
+ if (j) {
+ RPRINTF("ramdisk queue returned %d\n", j);
+ free(cbdata);
+ free(buf);
+ break;
+ }
+
+ s->ramdisk.inflight++;
+
+ for (j = 0; j < batchlen; j++) {
+ hashtable_remove(s->ramdisk.prev, &base);
+ base++;
+ }
+ }
+
+ if (!hashtable_count(s->ramdisk.prev)) {
+ /* everything is in flight */
+ hashtable_destroy(s->ramdisk.prev, 0);
+ s->ramdisk.prev = NULL;
+ }
+
+ free(sectors);
+
+ /*
+ RPRINTF("submitting requests\n");
+ */
+ dd->private = s->driver_data;
+ j = s->driver->td_submit(dd);
+ dd->private = s;
+ /*
+ RPRINTF("submit returned %d\n", j);
+ */
+
+ return 0;
+}
+
+/* flush ramdisk contents to disk */
+static int ramdisk_start_flush(struct disk_driver* dd)
+{
+ struct tdremus_state *s = (struct tdremus_state *)dd->private;
+ uint64_t* key;
+ char* buf;
+ int rc = 0;
+ int i, j, count, batchlen;
+ uint64_t* sectors;
+
+ if (!hashtable_count(s->ramdisk.h)) {
+ /*
+ RPRINTF("Nothing to flush\n");
+ */
+ return 0;
+ }
+
+ if (s->ramdisk.prev) {
+ /* a flush request issued while a previous flush is still in progress
+ * will merge with the previous request. If you want the previous
+ * request to be consistent, wait for it to complete. */
+ if ((count = ramdisk_get_sectors(s->ramdisk.h, §ors)) < 0)
+ return count;
+
+ for (i = 0; i < count; i++) {
+ buf = hashtable_search(s->ramdisk.h, sectors + i);
+ ramdisk_write_hash(s->ramdisk.prev, sectors[i], buf,
+ s->ramdisk.sector_size);
+ }
+ free(sectors);
+
+ hashtable_destroy (s->ramdisk.h, 0);
+ } else
+ s->ramdisk.prev = s->ramdisk.h;
+
+ /* We create a new hashtable so that new writes can be performed before
+ * the old hashtable is completely drained. */
+ s->ramdisk.h = create_hashtable(RAMDISK_HASHSIZE, uint64_hash,
+ rd_hash_equal);
+
+ return ramdisk_flush(dd, s);
+}
+
+static int ramdisk_queue_close(struct disk_driver* dd)
+{
+ struct tdremus_state *s = (struct tdremus_state *)dd->private;
+
+ hashtable_destroy(s->ramdisk.h, 1);
+
+ return 0;
+}
+
+static int ramdisk_start(struct disk_driver* dd)
+{
+ struct tdremus_state *s = (struct tdremus_state *)dd->private;
+
+ if (s->ramdisk.h) {
+ RPRINTF("ramdisk already allocated\n");
+ return 0;
+ }
+
+ s->ramdisk.sector_size = dd->td_state->sector_size;
+ s->ramdisk.h = create_hashtable(RAMDISK_HASHSIZE, uint64_hash,
+ rd_hash_equal);
+
+ DPRINTF("Ramdisk started, %zu bytes/sector\n", s->ramdisk.sector_size);
+
+ return 0;
+}
+
+/* common client/server functions */
+/* mayberead: Time out after a certain interval. */
+static int mread(int fd, void* buf, size_t len)
+{
+ fd_set rfds;
+ int rc;
+ size_t cur = 0;
+ struct timeval tv = {
+ .tv_sec = 0,
+ .tv_usec = NET_TIMEOUT * 1000
+ };
+
+ if (!len)
+ return 0;
+
+ /* read first. Only select if read is incomplete. */
+ rc = read(fd, buf, len);
+ while (rc < 0 || cur + rc < len) {
+ if (!rc) {
+ RPRINTF("end-of-file");
+ return -1;
+ }
+ if (rc < 0 && errno != EAGAIN) {
+ RPRINTF("error during read: %d\n", errno);
+ return -1;
+ }
+ if (rc > 0)
+ cur += rc;
+
+ FD_ZERO(&rfds);
+ FD_SET(fd, &rfds);
+ if (!(rc = select(fd + 1, &rfds, NULL, NULL, &tv))) {
+ RPRINTF("time out during read\n");
+ return -1;
+ } else if (rc < 0) {
+ RPRINTF("error during select: %d\n", errno);
+ return -1;
+ }
+ rc = read(fd, buf + cur, len - cur);
+ }
+ /*
+ RPRINTF("read %d bytes\n", cur + rc);
+ */
+
+ return 0;
+}
+
+static int mwrite(int fd, void* buf, size_t len)
+{
+ fd_set wfds;
+ size_t cur = 0;
+ int rc;
+ struct timeval tv = {
+ .tv_sec = 0,
+ .tv_usec = NET_TIMEOUT * 1000
+ };
+
+ if (!len)
+ return 0;
+
+ /* read first. Only select if read is incomplete. */
+ rc = write(fd, buf, len);
+ while (rc < 0 || cur + rc < len) {
+ if (!rc) {
+ RPRINTF("end-of-file");
+ return -1;
+ }
+ if (rc < 0 && errno != EAGAIN) {
+ RPRINTF("error during read: %d\n", errno);
+ return -1;
+ }
+ if (rc > 0)
+ cur += rc;
+
+ FD_ZERO(&wfds);
+ FD_SET(fd, &wfds);
+ if (!(rc = select(fd + 1, NULL, &wfds, NULL, &tv))) {
+ RPRINTF("time out during write\n");
+ return -1;
+ } else if (rc < 0) {
+ RPRINTF("error during select: %d\n", errno);
+ return -1;
+ }
+ rc = write(fd, buf + cur, len - cur);
+ }
+ /*
+ RPRINTF("wrote %d bytes\n", cur + rc);
+ */
+
+ return 0;
+ FD_ZERO(&wfds);
+ FD_SET(fd, &wfds);
+ select(fd + 1, NULL, &wfds, NULL, &tv);
+}
+
+/* add a new FD to tapdisk selector */
+static int install_tdfd(struct disk_driver* dd, int* pidx, int fd) {
+ int idx;
+
+ for (idx = 0; idx < MAX_IOFD; idx++) {
+ if (!dd->io_fd[idx])
+ break;
+ }
+ if (idx == MAX_IOFD) {
+ RPRINTF("no free FD for replication channel\n");
+ return -1;
+ }
+
+ dd->io_fd[idx] = fd;
+ *pidx = idx;
+
+ return 0;
+}
+
+static int close_rfd(struct disk_driver* dd)
+{
+ struct tdremus_state *s = (struct tdremus_state *)dd->private;
+
+ RPRINTF("closing replication channel\n");
+
+ close(s->rfd);
+ s->rfd = -2;
+ dd->io_fd[s->rfd_idx] = 0;
+ s->rfd_idx = -1;
+
+ return 0;
+}
+
+/* remus client */
+
+static int client_connect(struct disk_driver* dd)
+{
+ struct tdremus_state *s = (struct tdremus_state *)dd->private;
+ struct sockaddr_in sa;
+ int fd;
+ int rc;
+
+ RPRINTF("client connecting to %s:%d...\n", inet_ntoa(s->addr), s->port);
+
+ if ((fd = socket(PF_INET, SOCK_STREAM, 0)) < 0) {
+ RPRINTF("could not create client socket: %d\n", errno);
+ return -1;
+ }
+
+ memset(&sa, 0, sizeof(sa));
+ sa.sin_family = AF_INET;
+ sa.sin_addr.s_addr = s->addr.s_addr;
+ sa.sin_port = htons(s->port);
+ /* wait for remote end to start up */
+ do {
+ if ((rc = connect(fd, &sa, sizeof(sa))) < 0) {
+ if (errno == ECONNREFUSED) {
+ RPRINTF("connection refused -- retrying in 1 second\n");
+ sleep(1);
+ } else {
+ RPRINTF("connection failed: %d\n", errno);
+ goto err_sock;
+ }
+ }
+ } while (rc < 0);
+
+ RPRINTF("client connected\n");
+
+ if (install_tdfd(dd, &s->rfd_idx, fd) < 0)
+ goto err_sock;
+ RPRINTF("replication channel in slot %d\n", s->rfd_idx);
+
+ if (fcntl(fd, F_SETFL, O_NONBLOCK) < 0) {
+ RPRINTF("error making socket non-blocking\n");
+ goto err_sock;
+ }
+
+ s->rfd = fd;
+
+ return 0;
+
+ err_sock:
+ close(fd);
+ return -1;
+}
+
+static int client_replicate(struct disk_driver* dd)
+{
+ struct tdremus_state *s = (struct tdremus_state *)dd->private;
+ struct tdremus_req* req;
+ int len, rc;
+ uint64_t header[2];
+
+ /* -2 means connection ended -- give up replication */
+ if (s->rfd == -2) {
+ RPRINTF("engaging passthrough mode\n");
+ pass_start(dd);
+ s->mode == mode_pass;
+ return 0;
+ }
+
+ if (ring_isempty(&s->write_ring))
+ return 0;
+
+ if (s->rfd < 0 && client_connect(dd) < 0) {
+ RPRINTF("replication failed");
+ return -1;
+ }
+ /* TODO: it would probably make sense to send the header for all
+ * requests in this batch in one write. */
+ memcpy(header, "wreq", 4);
+ while (!ring_isempty(&s->write_ring)) {
+ req = s->write_ring.requests + s->write_ring.head;
+ ((uint32_t*)header)[1] = req->nb_sectors;
+ header[1] = req->sector;
+
+ /*
+ RPRINTF("sending write request: %lu bytes at %llu\n",
+ req->nb_sectors * dd->td_state->sector_size, req->sector);
+ */
+
+ if (mwrite(s->rfd, header, sizeof(header)) < 0)
+ goto err_write;
+ if (mwrite(s->rfd, req->buf,
+ req->nb_sectors * dd->td_state->sector_size) < 0)
+ goto err_write;
+
+ s->write_ring.head = ring_next(&s->write_ring, s->write_ring.head);
+ }
+ /* submit barrier */
+ /*
+ RPRINTF("sending submit\n");
+ if (mwrite(s->rfd, "sreq", 4) < 0)
+ goto err_write;
+ */
+
+ return 0;
+
+ err_write:
+ close_rfd(dd);
+ return -1;
+}
+
+/* store a copy of the request in order to replicate it at submit */
+static int client_queue_write(struct disk_driver *dd, uint64_t sector,
+ int nb_sectors, char *buf, td_callback_t cb,
+ int id, void *private)
+{
+ struct tdremus_state *s = (struct tdremus_state *)dd->private;
+ int rc;
+
+ /* this is probably unsafe: if the underlying disk makes the callback
+ * before the request has been propagated, the buffer may be damaged.
+ * Perhaps the callback should be overridden to ensure the request
+ * has been sent before continuing. Or maybe we should just copy the
+ * buffer. */
+ /* UPDATE: using copies now */
+ if (ring_isfull(&s->write_ring)) {
+ RPRINTF("ring full, flushing\n");
+ client_replicate(dd);
+ }
+
+ /* client_replicate may have disabled replication on error */
+ if (s->mode == mode_client)
+ if ((rc = buf_queue_write(dd, sector, nb_sectors, buf)) < 0) {
+ RPRINTF("buf_queue_write returned %d\n", rc);
+ return rc;
+ }
+ dd->private = s->driver_data;
+ rc = s->driver->td_queue_write(dd, sector, nb_sectors, buf, cb, id,
+ private);
+ dd->private = s;
+
+ return rc;
+}
+
+/* submit requests, then replicate them while the underlying disk
+ * is handling the requests */
+static int client_submit(struct disk_driver* dd)
+{
+ struct tdremus_state *s = (struct tdremus_state *)dd->private;
+ int rc;
+
+ dd->private = s->driver_data;
+ rc = s->driver->td_submit(dd);
+ dd->private = s;
+
+ client_replicate(dd);
+
+ return rc;
+}
+
+static int client_flush(struct disk_driver* dd)
+{
+ struct tdremus_state *s = (struct tdremus_state *)dd->private;
+
+ /*
+ RPRINTF("committing output\n");
+ */
+
+ if (mwrite(s->rfd, "creq", 4) < 0) {
+ close_rfd(dd);
+ }
+
+ return 0;
+}
+
+static int client_start(struct disk_driver* dd)
+{
+ struct tdremus_state *s = (struct tdremus_state *)dd->private;
+
+ RPRINTF("activating client mode\n");
+
+ s->queue_write = client_queue_write;
+ s->submit = client_submit;
+ s->queue_flush = client_flush;
+
+ return 0;
+}
+
+/* wait for "done" message to commit checkpoint */
+static int client_do_replicate(struct disk_driver* dd)
+{
+ struct tdremus_state *s = (struct tdremus_state *)dd->private;
+ char buf[5];
+ int rc;
+
+ buf[4] = '\0';
+ if (mread(s->rfd, buf, 4) < 0) {
+ close_rfd(dd);
+ return -1;
+ }
+
+ if (!strncmp(buf, "done", 4)) {
+ if ((rc = write(s->msgfd, buf, 4)) < 0) {
+ RPRINTF("error writing notification: %d\n", errno);
+
+ close(s->msgfd);
+ if ((s->msgfd = open(s->msgfifo, O_RDWR)) < 0) {
+ RPRINTF("error reopening FIFO: %d\n", errno);
+ return -1;
+ }
+ }
+ } else
+ RPRINTF("received unknown message: %s\n", buf);
+
+ return 0;
+}
+
+/* remus server */
+
+/* returns the socket that receives write requests */
+static int remus_accept(struct tdremus_state* s)
+{
+ int fd;
+ struct sockaddr_in sa;
+ socklen_t sa_len;
+
+ RPRINTF("server waiting for connection\n");
+ sa_len = sizeof(sa);
+ if ((fd = accept(s->sfd, &sa, &sa_len)) < 0) {
+ RPRINTF("error accepting connection: %d\n", errno);
+ return -1;
+ }
+
+ RPRINTF("server accepted connection\n");
+
+ return fd;
+}
+
+/* returns -2 if EADDRNOTAVAIL */
+static int remus_bind(struct tdremus_state* s)
+{
+ struct sockaddr_in sa;
+ int opt;
+ int rc = -1;
+
+ if ((s->sfd = socket(AF_INET, SOCK_STREAM, 0)) < 0) {
+ RPRINTF("could not create server socket: %d\n", errno);
+ return rc;
+ }
+ opt = 1;
+ if (setsockopt(s->sfd, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt)) < 0)
+ RPRINTF("Error setting REUSEADDR on %d: %d\n", s->sfd, errno);
+
+ memset(&sa, 0, sizeof(sa));
+ sa.sin_family = AF_INET;
+ sa.sin_addr.s_addr = s->addr.s_addr;
+ sa.sin_port = htons(s->port);
+ if (bind(s->sfd, &sa, sizeof(sa)) < 0) {
+ RPRINTF("could not bind server socket %d to %s:%d: %d %s\n", s->sfd,
+ inet_ntoa(sa.sin_addr), s->port, errno, strerror(errno));
+ if (errno != EADDRINUSE)
+ rc = -2;
+ goto err_sfd;
+ }
+ if (listen(s->sfd, 10)) {
+ RPRINTF("could not listen on socket: %d\n", errno);
+ goto err_sfd;
+ }
+
+ return 0;
+
+ err_sfd:
+ close(s->sfd);
+ s->sfd = -1;
+
+ return rc;
+}
+
+/* wait for latest checkpoint to be applied */
+static inline int server_writes_inflight(struct disk_driver* dd)
+{
+ struct tdremus_state *s = (struct tdremus_state *)dd->private;
+
+ if (!s->ramdisk.inflight && !s->ramdisk.prev)
+ return 0;
+
+ return 1;
+}
+
+/* this should not be called until the domain has failed over.
+ * Its duty is to make sure the latest checkpoint is applied
+ * before resuming. */
+static int server_queue_read(struct disk_driver *dd, uint64_t sector,
+ int nb_sectors, char *buf, td_callback_t cb,
+ int id, void *private)
+{
+ struct tdremus_state *s = (struct tdremus_state *)dd->private;
+
+ if (server_writes_inflight(dd)) {
+ RPRINTF("queue_read: waiting for queue to drain");
+ return -EBUSY;
+ }
+
+ RPRINTF("queue_read: activating backup");
+ pass_start(dd);
+ tdremus_queue_read(dd, sector, nb_sectors, buf, cb, id, private);
+
+ return 0;
+}
+
+/* see above */
+static int server_queue_write(struct disk_driver *dd, uint64_t sector,
+ int nb_sectors, char *buf, td_callback_t cb,
+ int id, void *private)
+{
+ struct tdremus_state *s = (struct tdremus_state *)dd->private;
+
+ if (server_writes_inflight(dd)) {
+ RPRINTF("queue_write: waiting for queue to drain");
+ return -EBUSY;
+ }
+
+ RPRINTF("queue_write: activating backup");
+ pass_start(dd);
+ tdremus_queue_write(dd, sector, nb_sectors, buf, cb, id, private);
+
+ return 0;
+}
+
+static int server_start(struct disk_driver* dd)
+{
+ struct tdremus_state *s = (struct tdremus_state *)dd->private;
+ int fd;
+
+ if (install_tdfd(dd, &s->rfd_idx, s->sfd) < 0)
+ return -1;
+
+ if (ramdisk_start(dd) < 0)
+ return -1;
+
+ RPRINTF("server listening in slot %d\n", s->rfd_idx);
+
+ s->queue_read = server_queue_read;
+ s->queue_write = server_queue_write;
+
+ return 0;
+}
+
+/* writes should be appended to a journal */
+static int server_do_wreq(struct disk_driver* dd)
+{
+ struct tdremus_state *s = (struct tdremus_state *)dd->private;
+ char buf[4096];
+ uint64_t sector;
+ int nb_sectors, len, rc;
+
+ /*
+ RPRINTF("received write request\n");
+ */
+
+ if (mread(s->rfd, buf, 12) < 0)
+ goto err_read;
+
+ nb_sectors = *(uint32_t*)buf;
+ memcpy(§or, buf + 4, sizeof(sector));
+ len = nb_sectors * dd->td_state->sector_size;
+
+ /*
+ RPRINTF("writing %d sectors (%d bytes) starting at %llu\n", nb_sectors, len,
+ sector);
+ */
+
+ if (len > sizeof(buf)) {
+ /* freak out! */
+ RPRINTF("write request too large: %d/%u\n", len, (unsigned)sizeof(buf));
+ return -1;
+ }
+
+ if (mread(s->rfd, buf, len) < 0)
+ goto err_read;
+
+ ramdisk_write(&s->ramdisk, sector, nb_sectors, buf);
+
+ return 0;
+
+ err_read:
+ /* should start failover */
+ close_rfd(dd);
+
+ return -1;
+}
+
+static int server_do_sreq(struct disk_driver* dd)
+{
+ /*
+ RPRINTF("submit request received\n");
+ */
+
+ return 0;
+}
+
+/* at this point, the server can start applying the most recent
+ * ramdisk. */
+static int server_do_creq(struct disk_driver* dd)
+{
+ struct tdremus_state *s = (struct tdremus_state *)dd->private;
+
+ /*
+ RPRINTF("committing buffer\n");
+ */
+
+ ramdisk_start_flush(dd);
+
+ /* profit! */
+ if (write(s->rfd, "done", 4) != 4)
+ return -1;
+
+ return 0;
+}
+
+/* called when data is pending in s->rfd */
+static int server_do_replicate(struct disk_driver* dd)
+{
+ struct tdremus_state *s = (struct tdremus_state *)dd->private;
+ char req[5];
+ int fd;
+
+ if (dd->io_fd[s->rfd_idx] == s->sfd) {
+ /* connection not yet established. Bring it up. */
+ if ((fd = remus_accept(s)) < 0)
+ return -1;
+
+ s->rfd = fd;
+ dd->io_fd[s->rfd_idx] = s->rfd;
+
+ if (fcntl(fd, F_SETFL, O_NONBLOCK) < 0) {
+ RPRINTF("error making socket non-blocking\n");
+ close_rfd(dd);
+ dd->io_fd[s->rfd_idx] = s->sfd;
+ return -1;
+ }
+
+ RPRINTF("replication channel in slot %d\n", s->rfd_idx);
+
+ return 0;
+ }
+
+ /*
+ RPRINTF("replication data waiting\n");
+ */
+
+ if (mread(s->rfd, req, 4) < 0) {
+ close_rfd(dd);
+ /* TODO: initiate failover recovery */
+ return -1;
+ }
+ req[5] = '\0';
+
+ /*
+ RPRINTF("received request: %s\n", req);
+ */
+
+ if (!strncmp(req, "wreq", 4))
+ return server_do_wreq(dd);
+ else if (!strncmp(req, "sreq", 4))
+ return server_do_sreq(dd);
+ else if (!strncmp(req, "creq", 4))
+ return server_do_creq(dd);
+ else
+ RPRINTF("unknown request received: %s\n", req);
+
+ return 0;
+}
+
+/* control */
+
+static inline int resolve_address(const char* addr, struct in_addr* ia)
+{
+ struct hostent* he;
+ uint32_t ip;
+
+ if (!(he = gethostbyname(addr))) {
+ RPRINTF("error resolving %s: %d\n", addr, h_errno);
+ return -1;
+ }
+
+ if (!he->h_addr_list[0]) {
+ RPRINTF("no address found for %s\n", addr);
+ return -1;
+ }
+
+ /* network byte order */
+ ip = *((uint32_t**)he->h_addr_list)[0];
+ ia->s_addr = ip;
+
+ return 0;
+}
+
+static int get_driver(struct disk_driver* dd, const char* name)
+{
+ struct tdremus_state *s = (struct tdremus_state *)dd->private;
+ char* host;
+ char* ports;
+ char* driver;
+ char* parent;
+ unsigned long ulport;
+ disk_info_t* disk_info = NULL;
+ int nr_drivers = sizeof(dtypes) / sizeof(disk_info_t*);
+ int i;
+
+ ports = strchr(name, ':');
+ if (!ports) {
+ RPRINTF("missing host in %s\n", name);
+ return -ENOENT;
+ }
+ if (!(host = strndup(name, ports - name))) {
+ RPRINTF("unable to allocate host\n");
+ return -ENOMEM;
+ }
+ ports++;
+ if (resolve_address(host, &s->addr) < 0) {
+ RPRINTF("unable to resolve host: %s\n", host);
+ free(host);
+ return -ENOENT;
+ }
+ free(host);
+
+ if (!(ulport = strtoul(ports, &driver, 10))) {
+ RPRINTF("missing port in %s\n", name);
+ return -ENOENT;
+ }
+ if (ulport > 65535) {
+ RPRINTF("port out of range: %lu\n", ulport);
+ return -ENOENT;
+ }
+ s->port = (unsigned short)ulport;
+ if (driver[0] != ':') {
+ RPRINTF("missing driver in %s\n", name);
+ return -ENOENT;
+ }
+ driver++;
+
+ parent = strchr(driver, ':');
+ if (!parent) {
+ RPRINTF("missing parent for %s\n", name);
+ return -ENOENT;
+ }
+ parent++;
+ s->path = strdup(parent);
+
+ RPRINTF("host: %s, port: %d\n", inet_ntoa(s->addr), s->port);
+ for (i = 0; i < nr_drivers; i ++)
+ if (!strncmp(driver, dtypes[i]->handle, strlen(dtypes[i]->handle)))
+ disk_info = dtypes[i];
+
+ if (disk_info) {
+ RPRINTF("found driver %s for %s\n", disk_info->handle, parent);
+ s->driver = disk_info->drv;
+
+ return 0;
+ }
+
+ RPRINTF("no driver found for %s\n", name);
+
+ err_driver:
+ free(s->path);
+ s->path = NULL;
+ return -ENOENT;
+}
+
+static int switch_mode(struct disk_driver* dd, enum tdremus_mode mode)
+{
+ struct tdremus_state *s = (struct tdremus_state *)dd->private;
+ int rc;
+
+ if (mode == s->mode)
+ return 0;
+
+ if (s->queue_flush)
+ if ((rc = s->queue_flush(dd)) < 0)
+ return rc;
+
+ if (mode == mode_pass)
+ rc = pass_start(dd);
+ if (mode == mode_client)
+ rc = client_start(dd);
+ else if (mode == mode_server)
+ rc = server_start(dd);
+ else {
+ RPRINTF("unknown mode requested: %d\n", mode);
+ rc = -1;
+ }
+
+ if (!rc)
+ s->mode = mode;
+
+ return rc;
+}
+
+static int do_ctl(struct disk_driver* dd)
+{
+ struct tdremus_state *s = (struct tdremus_state *)dd->private;
+ int ctlfd = dd->io_fd[s->ctl_fd_idx];
+ char msg[80];
+ int rc;
+
+ if (!(rc = read(ctlfd, msg, sizeof(msg) - 1 /* append nul */))) {
+ RPRINTF("0-byte read received, reopening FIFO\n");
+ close(ctlfd);
+ if ((ctlfd = open(s->ctlfifo, O_RDWR)) < 0) {
+ RPRINTF("error reopening FIFO: %d\n", errno);
+ return -1;
+ }
+ dd->io_fd[s->ctl_fd_idx] = ctlfd;
+ return 0;
+ }
+
+ if (rc < 0) {
+ RPRINTF("error reading from FIFO: %d\n", errno);
+ return -1;
+ }
+
+ msg[rc] = '\0';
+ if (!strncmp(msg, "flush", 5)) {
+ if (s->queue_flush)
+ return s->queue_flush(dd);
+ else
+ return 0;
+ } else {
+ RPRINTF("unknown command: %s\n", msg);
+ }
+
+ return 0;
+}
+
+/* must be called after the underlying driver has been initialized */
+static int add_ctl_hook(struct disk_driver* dd, const char* name)
+{
+ struct tdremus_state *s = (struct tdremus_state *)dd->private;
+ int i, l;
+
+ for (s->ctl_fd_idx = 0; s->ctl_fd_idx < MAX_IOFD; s->ctl_fd_idx++) {
+ if (!dd->io_fd[s->ctl_fd_idx])
+ break;
+ }
+ if (s->ctl_fd_idx == MAX_IOFD) {
+ RPRINTF("no free FD for control channel\n");
+ return -1;
+ }
+
+ /* device name -> FIFO */
+ if (asprintf(&s->ctlfifo, BLKTAP_CTRL_DIR "/remus_%s", name) < 0)
+ return -1;
+ for (i = strlen(BLKTAP_CTRL_DIR) + 1, l = strlen(s->ctlfifo); i < l; i++) {
+ if (strchr(":/", s->ctlfifo[i]))
+ s->ctlfifo[i] = '_';
+ }
+ if (asprintf(&s->msgfifo, "%s.msg", s->ctlfifo) < 0)
+ goto err_ctlfifo;
+
+ if (mkfifo(s->ctlfifo, S_IRWXU|S_IRWXG|S_IRWXO) && errno != EEXIST) {
+ RPRINTF("error creating control FIFO %s: %d\n", s->ctlfifo, errno);
+ goto err_msgfifo;
+ }
+
+ if (mkfifo(s->msgfifo, S_IRWXU|S_IRWXG|S_IRWXO) && errno != EEXIST) {
+ RPRINTF("error creating message FIFO %s: %d\n", s->msgfifo, errno);
+ goto err_msgfifo;
+ }
+
+ /* RDWR so that fd doesn't block select when no writer is present */
+ if ((dd->io_fd[s->ctl_fd_idx] = open(s->ctlfifo, O_RDWR)) < 0) {
+ RPRINTF("error opening control FIFO %s: %d\n", s->ctlfifo, errno);
+ goto err_msgfifo;
+ }
+
+ if ((s->msgfd = open(s->msgfifo, O_RDWR)) < 0) {
+ RPRINTF("error opening message FIFO %s: %d\n", s->msgfifo, errno);
+ goto err_openctlfifo;
+ }
+
+ RPRINTF("control FIFO %s\n", s->ctlfifo);
+ RPRINTF("message FIFO %s\n", s->msgfifo);
+
+ return 0;
+
+ err_openctlfifo:
+ close(dd->io_fd[s->ctl_fd_idx]);
+ dd->io_fd[s->ctl_fd_idx] = 0;
+ err_msgfifo:
+ free(s->msgfifo);
+ s->msgfifo = NULL;
+ err_ctlfifo:
+ free(s->ctlfifo);
+ s->ctlfifo = NULL;
+ s->ctl_fd_idx = -1;
+ return -1;
+}
+
+static void del_ctl_hook(struct disk_driver* dd)
+{
+ struct tdremus_state *s = (struct tdremus_state *)dd->private;
+
+ if (dd->io_fd[s->ctl_fd_idx]) {
+ close(dd->io_fd[s->ctl_fd_idx]);
+ dd->io_fd[s->ctl_fd_idx] = 0;
+ }
+ if (s->ctlfifo) {
+ unlink(s->ctlfifo);
+ free(s->ctlfifo);
+ s->ctlfifo = NULL;
+ }
+}
+
+/* interface */
+
+static int tdremus_open (struct disk_driver *dd, const char *name,
+ td_flag_t flags)
+{
+ struct tdremus_state *s = (struct tdremus_state *)dd->private;
+ int rc;
+
+ RPRINTF("opening %s\n", name);
+
+ memset(s, 0, sizeof(*s));
+ s->sfd = -1;
+ s->rfd = -1;
+ s->ctl_fd_idx = -1;
+ s->rfd_idx = -1;
+
+ if ((rc = get_driver(dd, name)))
+ return rc;
+
+ if (!(s->driver_data = malloc(s->driver->private_data_size))) {
+ RPRINTF("could not allocate driver data\n");
+ return -ENOMEM;
+ }
+
+ dd->private = s->driver_data;
+ if ((rc = s->driver->td_open(dd, s->path, flags))) {
+ RPRINTF("could not open driver\n");
+ dd->private = s;
+ free(s->driver_data);
+ return rc;
+ }
+ dd->private = s;
+
+ if ((rc = add_ctl_hook(dd, name))) {
+ RPRINTF("error setting up control channel\n");
+ free(s->driver_data);
+ return rc;
+ }
+
+ if ((rc = remus_bind(s))) {
+ if (rc == -2) {
+ rc = switch_mode(dd, mode_client);
+ } else
+ goto err_path;
+ } else
+ rc = switch_mode(dd, mode_server);
+
+ if (rc) {
+ tdremus_close(dd);
+ return -EIO;
+ }
+
+ return 0;
+
+ err_path:
+ free(s->path);
+ s->path = NULL;
+ return rc;
+}
+
+static int tdremus_queue_read(struct disk_driver *dd, uint64_t sector,
+ int nb_sectors, char *buf, td_callback_t cb,
+ int id, void *private)
+{
+ struct tdremus_state *s = (struct tdremus_state *)dd->private;
+ int rc;
+
+ if (s->queue_read)
+ return s->queue_read(dd, sector, nb_sectors, buf, cb, id, private);
+
+ dd->private = s->driver_data;
+ rc = s->driver->td_queue_read(dd, sector, nb_sectors, buf, cb, id, private);
+ dd->private = s;
+
+ return rc;
+}
+
+static int tdremus_queue_write(struct disk_driver *dd, uint64_t sector,
+ int nb_sectors, char *buf, td_callback_t cb,
+ int id, void *private)
+{
+ struct tdremus_state *s = (struct tdremus_state *)dd->private;
+ int rc;
+
+ if (s->queue_write)
+ return s->queue_write(dd, sector, nb_sectors, buf, cb, id, private);
+
+ dd->private = s->driver_data;
+ rc = s->driver->td_queue_write(dd, sector, nb_sectors, buf, cb, id,
+ private);
+ dd->private = s;
+
+ return rc;
+}
+
+static int tdremus_submit(struct disk_driver *dd)
+{
+ struct tdremus_state *s = (struct tdremus_state *)dd->private;
+ int rc;
+
+ if (s->submit)
+ return s->submit(dd);
+
+ dd->private = s->driver_data;
+ rc = s->driver->td_submit(dd);
+ dd->private = s;
+
+ return rc;
+}
+
+static int tdremus_close(struct disk_driver *dd)
+{
+ struct tdremus_state *s = (struct tdremus_state *)dd->private;
+ int rc;
+
+ RPRINTF("closing\n");
+
+ dd->private = s->driver_data;
+ rc = s->driver->td_close(dd);
+ dd->private = s;
+
+ if (s->driver_data) {
+ free(s->driver_data);
+ s->driver_data = NULL;
+ }
+ if (s->sfd >= 0) {
+ close(s->sfd);
+ s->sfd = -1;
+ }
+ if (s->rfd >= 0) {
+ close_rfd(dd);
+ }
+ if (s->path) {
+ free(s->path);
+ s->path = NULL;
+ }
+
+ del_ctl_hook(dd);
+
+ return rc;
+}
+
+static int tdremus_do_callbacks(struct disk_driver *dd, int sid)
+{
+ struct tdremus_state *s = (struct tdremus_state *)dd->private;
+ int rc;
+
+ if (sid == s->ctl_fd_idx)
+ return do_ctl(dd);
+ if (sid == s->rfd_idx) {
+ if (s->mode == mode_client)
+ return client_do_replicate(dd);
+ else
+ return server_do_replicate(dd);
+ }
+
+ dd->private = s->driver_data;
+ rc = s->driver->td_do_callbacks(dd, sid);
+ dd->private = s;
+
+ return rc;
+}
+
+static int tdremus_get_parent_id(struct disk_driver *dd, struct disk_id *id)
+{
+ struct tdremus_state *s = (struct tdremus_state *)dd->private;
+ int rc;
+
+ dd->private = s->driver_data;
+ rc = s->driver->td_get_parent_id(dd, id);
+ dd->private = s;
+
+ return rc;
+}
+
+static int tdremus_validate_parent(struct disk_driver *dd,
+ struct disk_driver *parent, td_flag_t flags)
+{
+ struct tdremus_state *s = (struct tdremus_state *)dd->private;
+ int rc;
+
+ dd->private = s->driver_data;
+ rc = s->driver->td_validate_parent(dd, parent, flags);
+ dd->private = s;
+
+ return rc;
+}
+
+struct tap_disk tapdisk_remus = {
+ .disk_type = "tapdisk_remus",
+ .private_data_size = sizeof(struct tdremus_state),
+ .td_open = tdremus_open,
+ .td_queue_read = tdremus_queue_read,
+ .td_queue_write = tdremus_queue_write,
+ .td_submit = tdremus_submit,
+ .td_close = tdremus_close,
+ .td_do_callbacks = tdremus_do_callbacks,
+ .td_get_parent_id = tdremus_get_parent_id,
+ .td_validate_parent = tdremus_validate_parent
+};
diff --git a/tools/blktap/drivers/hashtable.c b/tools/blktap/drivers/hashtable.c
new file mode 100644
--- /dev/null
+++ b/tools/blktap/drivers/hashtable.c
@@ -0,0 +1,274 @@
+/* Copyright (C) 2004 Christopher Clark <firstname.lastname@xxxxxxxxxxxx> */
+
+#include "hashtable.h"
+#include "hashtable_private.h"
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <math.h>
+
+/*
+Credit for primes table: Aaron Krowne
+ http://br.endernet.org/~akrowne/
+ http://planetmath.org/encyclopedia/GoodHashTablePrimes.html
+*/
+static const unsigned int primes[] = {
+53, 97, 193, 389,
+769, 1543, 3079, 6151,
+12289, 24593, 49157, 98317,
+196613, 393241, 786433, 1572869,
+3145739, 6291469, 12582917, 25165843,
+50331653, 100663319, 201326611, 402653189,
+805306457, 1610612741
+};
+const unsigned int prime_table_length = sizeof(primes)/sizeof(primes[0]);
+const float max_load_factor = 0.65;
+
+/*****************************************************************************/
+struct hashtable *
+create_hashtable(unsigned int minsize,
+ unsigned int (*hashf) (void*),
+ int (*eqf) (void*,void*))
+{
+ struct hashtable *h;
+ unsigned int pindex, size = primes[0];
+ /* Check requested hashtable isn't too large */
+ if (minsize > (1u << 30)) return NULL;
+ /* Enforce size as prime */
+ for (pindex=0; pindex < prime_table_length; pindex++) {
+ if (primes[pindex] > minsize) { size = primes[pindex]; break; }
+ }
+ h = (struct hashtable *)malloc(sizeof(struct hashtable));
+ if (NULL == h) return NULL; /*oom*/
+ h->table = (struct entry **)malloc(sizeof(struct entry*) * size);
+ if (NULL == h->table) { free(h); return NULL; } /*oom*/
+ memset(h->table, 0, size * sizeof(struct entry *));
+ h->tablelength = size;
+ h->primeindex = pindex;
+ h->entrycount = 0;
+ h->hashfn = hashf;
+ h->eqfn = eqf;
+ h->loadlimit = (unsigned int) ceil(size * max_load_factor);
+ return h;
+}
+
+/*****************************************************************************/
+unsigned int
+hash(struct hashtable *h, void *k)
+{
+ /* Aim to protect against poor hash functions by adding logic here
+ * - logic taken from java 1.4 hashtable source */
+ unsigned int i = h->hashfn(k);
+ i += ~(i << 9);
+ i ^= ((i >> 14) | (i << 18)); /* >>> */
+ i += (i << 4);
+ i ^= ((i >> 10) | (i << 22)); /* >>> */
+ return i;
+}
+
+/*****************************************************************************/
+static int
+hashtable_expand(struct hashtable *h)
+{
+ /* Double the size of the table to accomodate more entries */
+ struct entry **newtable;
+ struct entry *e;
+ struct entry **pE;
+ unsigned int newsize, i, index;
+ /* Check we're not hitting max capacity */
+ if (h->primeindex == (prime_table_length - 1)) return 0;
+ newsize = primes[++(h->primeindex)];
+
+ newtable = (struct entry **)malloc(sizeof(struct entry*) * newsize);
+ if (NULL != newtable)
+ {
+ memset(newtable, 0, newsize * sizeof(struct entry *));
+ /* This algorithm is not 'stable'. ie. it reverses the list
+ * when it transfers entries between the tables */
+ for (i = 0; i < h->tablelength; i++) {
+ while (NULL != (e = h->table[i])) {
+ h->table[i] = e->next;
+ index = indexFor(newsize,e->h);
+ e->next = newtable[index];
+ newtable[index] = e;
+ }
+ }
+ free(h->table);
+ h->table = newtable;
+ }
+ /* Plan B: realloc instead */
+ else
+ {
+ newtable = (struct entry **)
+ realloc(h->table, newsize * sizeof(struct entry *));
+ if (NULL == newtable) { (h->primeindex)--; return 0; }
+ h->table = newtable;
+ memset(newtable[h->tablelength], 0, newsize - h->tablelength);
+ for (i = 0; i < h->tablelength; i++) {
+ for (pE = &(newtable[i]), e = *pE; e != NULL; e = *pE) {
+ index = indexFor(newsize,e->h);
+ if (index == i)
+ {
+ pE = &(e->next);
+ }
+ else
+ {
+ *pE = e->next;
+ e->next = newtable[index];
+ newtable[index] = e;
+ }
+ }
+ }
+ }
+ h->tablelength = newsize;
+ h->loadlimit = (unsigned int) ceil(newsize * max_load_factor);
+ return -1;
+}
+
+/*****************************************************************************/
+unsigned int
+hashtable_count(struct hashtable *h)
+{
+ return h->entrycount;
+}
+
+/*****************************************************************************/
+int
+hashtable_insert(struct hashtable *h, void *k, void *v)
+{
+ /* This method allows duplicate keys - but they shouldn't be used */
+ unsigned int index;
+ struct entry *e;
+ if (++(h->entrycount) > h->loadlimit)
+ {
+ /* Ignore the return value. If expand fails, we should
+ * still try cramming just this value into the existing table
+ * -- we may not have memory for a larger table, but one more
+ * element may be ok. Next time we insert, we'll try expanding again.*/
+ hashtable_expand(h);
+ }
+ e = (struct entry *)malloc(sizeof(struct entry));
+ if (NULL == e) { --(h->entrycount); return 0; } /*oom*/
+ e->h = hash(h,k);
+ index = indexFor(h->tablelength,e->h);
+ e->k = k;
+ e->v = v;
+ e->next = h->table[index];
+ h->table[index] = e;
+ return -1;
+}
+
+/*****************************************************************************/
+void * /* returns value associated with key */
+hashtable_search(struct hashtable *h, void *k)
+{
+ struct entry *e;
+ unsigned int hashvalue, index;
+ hashvalue = hash(h,k);
+ index = indexFor(h->tablelength,hashvalue);
+ e = h->table[index];
+ while (NULL != e)
+ {
+ /* Check hash value to short circuit heavier comparison */
+ if ((hashvalue == e->h) && (h->eqfn(k, e->k))) return e->v;
+ e = e->next;
+ }
+ return NULL;
+}
+
+/*****************************************************************************/
+void * /* returns value associated with key */
+hashtable_remove(struct hashtable *h, void *k)
+{
+ /* TODO: consider compacting the table when the load factor drops enough,
+ * or provide a 'compact' method. */
+
+ struct entry *e;
+ struct entry **pE;
+ void *v;
+ unsigned int hashvalue, index;
+
+ hashvalue = hash(h,k);
+ index = indexFor(h->tablelength,hash(h,k));
+ pE = &(h->table[index]);
+ e = *pE;
+ while (NULL != e)
+ {
+ /* Check hash value to short circuit heavier comparison */
+ if ((hashvalue == e->h) && (h->eqfn(k, e->k)))
+ {
+ *pE = e->next;
+ h->entrycount--;
+ v = e->v;
+ freekey(e->k);
+ free(e);
+ return v;
+ }
+ pE = &(e->next);
+ e = e->next;
+ }
+ return NULL;
+}
+
+/*****************************************************************************/
+/* destroy */
+void
+hashtable_destroy(struct hashtable *h, int free_values)
+{
+ unsigned int i;
+ struct entry *e, *f;
+ struct entry **table = h->table;
+ if (free_values)
+ {
+ for (i = 0; i < h->tablelength; i++)
+ {
+ e = table[i];
+ while (NULL != e)
+ { f = e; e = e->next; freekey(f->k); free(f->v); free(f); }
+ }
+ }
+ else
+ {
+ for (i = 0; i < h->tablelength; i++)
+ {
+ e = table[i];
+ while (NULL != e)
+ { f = e; e = e->next; freekey(f->k); free(f); }
+ }
+ }
+ free(h->table);
+ free(h);
+}
+
+/*
+ * Copyright (c) 2002, Christopher Clark
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *
+ * * Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * * Neither the name of the original author; nor the names of any contributors
+ * may be used to endorse or promote products derived from this software
+ * without specific prior written permission.
+ *
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
+ * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+ * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
diff --git a/tools/blktap/drivers/hashtable_itr.c
b/tools/blktap/drivers/hashtable_itr.c
new file mode 100644
--- /dev/null
+++ b/tools/blktap/drivers/hashtable_itr.c
@@ -0,0 +1,188 @@
+/* Copyright (C) 2002, 2004 Christopher Clark
<firstname.lastname@xxxxxxxxxxxx> */
+
+#include "hashtable.h"
+#include "hashtable_private.h"
+#include "hashtable_itr.h"
+#include <stdlib.h> /* defines NULL */
+
+/*****************************************************************************/
+/* hashtable_iterator - iterator constructor */
+
+struct hashtable_itr *
+hashtable_iterator(struct hashtable *h)
+{
+ unsigned int i, tablelength;
+ struct hashtable_itr *itr = (struct hashtable_itr *)
+ malloc(sizeof(struct hashtable_itr));
+ if (NULL == itr) return NULL;
+ itr->h = h;
+ itr->e = NULL;
+ itr->parent = NULL;
+ tablelength = h->tablelength;
+ itr->index = tablelength;
+ if (0 == h->entrycount) return itr;
+
+ for (i = 0; i < tablelength; i++)
+ {
+ if (NULL != h->table[i])
+ {
+ itr->e = h->table[i];
+ itr->index = i;
+ break;
+ }
+ }
+ return itr;
+}
+
+/*****************************************************************************/
+/* key - return the key of the (key,value) pair at the current position */
+/* value - return the value of the (key,value) pair at the current position
*/
+
+void *
+hashtable_iterator_key(struct hashtable_itr *i)
+{ return i->e->k; }
+
+void *
+hashtable_iterator_value(struct hashtable_itr *i)
+{ return i->e->v; }
+
+/*****************************************************************************/
+/* advance - advance the iterator to the next element
+ * returns zero if advanced to end of table */
+
+int
+hashtable_iterator_advance(struct hashtable_itr *itr)
+{
+ unsigned int j,tablelength;
+ struct entry **table;
+ struct entry *next;
+ if (NULL == itr->e) return 0; /* stupidity check */
+
+ next = itr->e->next;
+ if (NULL != next)
+ {
+ itr->parent = itr->e;
+ itr->e = next;
+ return -1;
+ }
+ tablelength = itr->h->tablelength;
+ itr->parent = NULL;
+ if (tablelength <= (j = ++(itr->index)))
+ {
+ itr->e = NULL;
+ return 0;
+ }
+ table = itr->h->table;
+ while (NULL == (next = table[j]))
+ {
+ if (++j >= tablelength)
+ {
+ itr->index = tablelength;
+ itr->e = NULL;
+ return 0;
+ }
+ }
+ itr->index = j;
+ itr->e = next;
+ return -1;
+}
+
+/*****************************************************************************/
+/* remove - remove the entry at the current iterator position
+ * and advance the iterator, if there is a successive
+ * element.
+ * If you want the value, read it before you remove:
+ * beware memory leaks if you don't.
+ * Returns zero if end of iteration. */
+
+int
+hashtable_iterator_remove(struct hashtable_itr *itr)
+{
+ struct entry *remember_e, *remember_parent;
+ int ret;
+
+ /* Do the removal */
+ if (NULL == (itr->parent))
+ {
+ /* element is head of a chain */
+ itr->h->table[itr->index] = itr->e->next;
+ } else {
+ /* element is mid-chain */
+ itr->parent->next = itr->e->next;
+ }
+ /* itr->e is now outside the hashtable */
+ remember_e = itr->e;
+ itr->h->entrycount--;
+ freekey(remember_e->k);
+
+ /* Advance the iterator, correcting the parent */
+ remember_parent = itr->parent;
+ ret = hashtable_iterator_advance(itr);
+ if (itr->parent == remember_e) { itr->parent = remember_parent; }
+ free(remember_e);
+ return ret;
+}
+
+/*****************************************************************************/
+int /* returns zero if not found */
+hashtable_iterator_search(struct hashtable_itr *itr,
+ struct hashtable *h, void *k)
+{
+ struct entry *e, *parent;
+ unsigned int hashvalue, index;
+
+ hashvalue = hash(h,k);
+ index = indexFor(h->tablelength,hashvalue);
+
+ e = h->table[index];
+ parent = NULL;
+ while (NULL != e)
+ {
+ /* Check hash value to short circuit heavier comparison */
+ if ((hashvalue == e->h) && (h->eqfn(k, e->k)))
+ {
+ itr->index = index;
+ itr->e = e;
+ itr->parent = parent;
+ itr->h = h;
+ return -1;
+ }
+ parent = e;
+ e = e->next;
+ }
+ return 0;
+}
+
+
+/*
+ * Copyright (c) 2002, 2004, Christopher Clark
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *
+ * * Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * * Neither the name of the original author; nor the names of any contributors
+ * may be used to endorse or promote products derived from this software
+ * without specific prior written permission.
+ *
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
+ * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+ * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
diff --git a/tools/blktap/drivers/hashtable_itr.h
b/tools/blktap/drivers/hashtable_itr.h
new file mode 100644
--- /dev/null
+++ b/tools/blktap/drivers/hashtable_itr.h
@@ -0,0 +1,112 @@
+/* Copyright (C) 2002, 2004 Christopher Clark
<firstname.lastname@xxxxxxxxxxxx> */
+
+#ifndef __HASHTABLE_ITR_CWC22__
+#define __HASHTABLE_ITR_CWC22__
+#include "hashtable.h"
+#include "hashtable_private.h" /* needed to enable inlining */
+
+/*****************************************************************************/
+/* This struct is only concrete here to allow the inlining of two of the
+ * accessor functions. */
+struct hashtable_itr
+{
+ struct hashtable *h;
+ struct entry *e;
+ struct entry *parent;
+ unsigned int index;
+};
+
+
+/*****************************************************************************/
+/* hashtable_iterator
+ */
+
+struct hashtable_itr *
+hashtable_iterator(struct hashtable *h);
+
+/*****************************************************************************/
+/* hashtable_iterator_key
+ * - return the value of the (key,value) pair at the current position */
+
+extern inline void *
+hashtable_iterator_key(struct hashtable_itr *i)
+{
+ return i->e->k;
+}
+
+/*****************************************************************************/
+/* value - return the value of the (key,value) pair at the current position */
+
+extern inline void *
+hashtable_iterator_value(struct hashtable_itr *i)
+{
+ return i->e->v;
+}
+
+/*****************************************************************************/
+/* advance - advance the iterator to the next element
+ * returns zero if advanced to end of table */
+
+int
+hashtable_iterator_advance(struct hashtable_itr *itr);
+
+/*****************************************************************************/
+/* remove - remove current element and advance the iterator to the next element
+ * NB: if you need the value to free it, read it before
+ * removing. ie: beware memory leaks!
+ * returns zero if advanced to end of table */
+
+int
+hashtable_iterator_remove(struct hashtable_itr *itr);
+
+/*****************************************************************************/
+/* search - overwrite the supplied iterator, to point to the entry
+ * matching the supplied key.
+ h points to the hashtable to be searched.
+ * returns zero if not found. */
+int
+hashtable_iterator_search(struct hashtable_itr *itr,
+ struct hashtable *h, void *k);
+
+#define DEFINE_HASHTABLE_ITERATOR_SEARCH(fnname, keytype) \
+int fnname (struct hashtable_itr *i, struct hashtable *h, keytype *k) \
+{ \
+ return (hashtable_iterator_search(i,h,k)); \
+}
+
+
+
+#endif /* __HASHTABLE_ITR_CWC22__*/
+
+/*
+ * Copyright (c) 2002, 2004, Christopher Clark
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *
+ * * Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * * Neither the name of the original author; nor the names of any contributors
+ * may be used to endorse or promote products derived from this software
+ * without specific prior written permission.
+ *
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
+ * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+ * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
diff --git a/tools/blktap/drivers/hashtable_utility.c
b/tools/blktap/drivers/hashtable_utility.c
new file mode 100644
--- /dev/null
+++ b/tools/blktap/drivers/hashtable_utility.c
@@ -0,0 +1,71 @@
+/* Copyright (C) 2002 Christopher Clark <firstname.lastname@xxxxxxxxxxxx> */
+
+#include "hashtable.h"
+#include "hashtable_private.h"
+#include "hashtable_utility.h"
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+
+/*****************************************************************************/
+/* hashtable_change
+ *
+ * function to change the value associated with a key, where there already
+ * exists a value bound to the key in the hashtable.
+ * Source due to Holger Schemel.
+ *
+ * */
+int
+hashtable_change(struct hashtable *h, void *k, void *v)
+{
+ struct entry *e;
+ unsigned int hashvalue, index;
+ hashvalue = hash(h,k);
+ index = indexFor(h->tablelength,hashvalue);
+ e = h->table[index];
+ while (NULL != e)
+ {
+ /* Check hash value to short circuit heavier comparison */
+ if ((hashvalue == e->h) && (h->eqfn(k, e->k)))
+ {
+ free(e->v);
+ e->v = v;
+ return -1;
+ }
+ e = e->next;
+ }
+ return 0;
+}
+
+/*
+ * Copyright (c) 2002, Christopher Clark
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *
+ * * Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * * Neither the name of the original author; nor the names of any contributors
+ * may be used to endorse or promote products derived from this software
+ * without specific prior written permission.
+ *
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
+ * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+ * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
diff --git a/tools/blktap/drivers/hashtable_utility.h
b/tools/blktap/drivers/hashtable_utility.h
new file mode 100644
--- /dev/null
+++ b/tools/blktap/drivers/hashtable_utility.h
@@ -0,0 +1,55 @@
+/* Copyright (C) 2002 Christopher Clark <firstname.lastname@xxxxxxxxxxxx> */
+
+#ifndef __HASHTABLE_CWC22_UTILITY_H__
+#define __HASHTABLE_CWC22_UTILITY_H__
+
+/*****************************************************************************
+ * hashtable_change
+ *
+ * function to change the value associated with a key, where there already
+ * exists a value bound to the key in the hashtable.
+ * Source due to Holger Schemel.
+ *
+ * @name hashtable_change
+ * @param h the hashtable
+ * @param key
+ * @param value
+ *
+ */
+int
+hashtable_change(struct hashtable *h, void *k, void *v);
+
+#endif /* __HASHTABLE_CWC22_H__ */
+
+/*
+ * Copyright (c) 2002, Christopher Clark
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *
+ * * Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * * Neither the name of the original author; nor the names of any contributors
+ * may be used to endorse or promote products derived from this software
+ * without specific prior written permission.
+ *
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
+ * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+ * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
diff --git a/tools/blktap/drivers/tapdisk.h b/tools/blktap/drivers/tapdisk.h
--- a/tools/blktap/drivers/tapdisk.h
+++ b/tools/blktap/drivers/tapdisk.h
@@ -160,6 +160,7 @@
extern struct tap_disk tapdisk_ram;
extern struct tap_disk tapdisk_qcow;
extern struct tap_disk tapdisk_qcow2;
+extern struct tap_disk tapdisk_remus;
/*Define Individual Disk Parameters here */
@@ -229,6 +230,17 @@
#endif
};
+static disk_info_t remus_disk = {
+ DISK_TYPE_REMUS,
+ "replicated disk (remus)",
+ "remus",
+ 0,
+ 0,
+#ifdef TAPDISK
+ &tapdisk_remus,
+#endif
+};
+
/*Main disk info array */
static disk_info_t *dtypes[] = {
&aio_disk,
@@ -237,6 +249,7 @@
&ram_disk,
&qcow_disk,
&qcow2_disk,
+ &remus_disk
};
typedef struct driver_list_entry {
diff --git a/tools/blktap/lib/blktaplib.h b/tools/blktap/lib/blktaplib.h
--- a/tools/blktap/lib/blktaplib.h
+++ b/tools/blktap/lib/blktaplib.h
@@ -219,6 +219,7 @@
#define DISK_TYPE_RAM 3
#define DISK_TYPE_QCOW 4
#define DISK_TYPE_QCOW2 5
+#define DISK_TYPE_REMUS 6
/* xenstore/xenbus: */
#define DOMNAME "Domain-0"
diff --git a/tools/python/xen/xend/server/BlktapController.py
b/tools/python/xen/xend/server/BlktapController.py
--- a/tools/python/xen/xend/server/BlktapController.py
+++ b/tools/python/xen/xend/server/BlktapController.py
@@ -14,6 +14,7 @@
'ram',
'qcow',
'qcow2',
+ 'remus',
'ioemu',
'tapdisk',
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