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pve-qemu/debian/patches/pve/0019-backup-vma-remove-asyn...

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From fb3d52b336cd8404055bf0b3b8d825c6f5247fef Mon Sep 17 00:00:00 2001
From: Wolfgang Bumiller <w.bumiller@proxmox.com>
Date: Wed, 9 Dec 2015 15:40:00 +0100
Subject: [PATCH 19/47] backup: vma: remove async queue
---
blockdev.c | 6 ++
vma-writer.c | 179 +++++++++++------------------------------------------------
2 files changed, 38 insertions(+), 147 deletions(-)
diff --git a/blockdev.c b/blockdev.c
index 2e51913..1491c2d 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -3116,6 +3116,11 @@ static void pvebackup_cancel(void *opaque)
error_setg(&backup_state.error, "backup cancelled");
}
+ if (backup_state.vmaw) {
+ /* make sure vma writer does not block anymore */
+ vma_writer_set_error(backup_state.vmaw, "backup cancelled");
+ }
+
/* drain all i/o (awake jobs waiting for aio) */
bdrv_drain_all();
@@ -3128,6 +3133,7 @@ static void pvebackup_cancel(void *opaque)
if (job) {
if (!di->completed) {
block_job_cancel_sync(job);
+ bdrv_drain_all(); /* drain all i/o (awake jobs waiting for aio) */
}
}
}
diff --git a/vma-writer.c b/vma-writer.c
index 689e988..6d3119d 100644
--- a/vma-writer.c
+++ b/vma-writer.c
@@ -28,14 +28,8 @@
do { if (DEBUG_VMA) { printf("vma: " fmt, ## __VA_ARGS__); } } while (0)
#define WRITE_BUFFERS 5
-
-typedef struct VmaAIOCB VmaAIOCB;
-struct VmaAIOCB {
- unsigned char buffer[VMA_MAX_EXTENT_SIZE];
- VmaWriter *vmaw;
- size_t bytes;
- Coroutine *co;
-};
+#define HEADER_CLUSTERS 8
+#define HEADERBUF_SIZE (VMA_CLUSTER_SIZE*HEADER_CLUSTERS)
struct VmaWriter {
int fd;
@@ -47,16 +41,14 @@ struct VmaWriter {
bool closed;
/* we always write extents */
- unsigned char outbuf[VMA_MAX_EXTENT_SIZE];
+ unsigned char *outbuf;
int outbuf_pos; /* in bytes */
int outbuf_count; /* in VMA_BLOCKS */
uint64_t outbuf_block_info[VMA_BLOCKS_PER_EXTENT];
- VmaAIOCB *aiocbs[WRITE_BUFFERS];
- CoQueue wqueue;
+ unsigned char *headerbuf;
GChecksum *md5csum;
- CoMutex writer_lock;
CoMutex flush_lock;
Coroutine *co_writer;
@@ -217,38 +209,39 @@ static void vma_co_continue_write(void *opaque)
}
static ssize_t coroutine_fn
-vma_co_write(VmaWriter *vmaw, const void *buf, size_t bytes)
+vma_queue_write(VmaWriter *vmaw, const void *buf, size_t bytes)
{
- size_t done = 0;
- ssize_t ret;
+ DPRINTF("vma_queue_write enter %zd\n", bytes);
- /* atomic writes (we cannot interleave writes) */
- qemu_co_mutex_lock(&vmaw->writer_lock);
+ assert(vmaw);
+ assert(buf);
+ assert(bytes <= VMA_MAX_EXTENT_SIZE);
- DPRINTF("vma_co_write enter %zd\n", bytes);
+ size_t done = 0;
+ ssize_t ret;
assert(vmaw->co_writer == NULL);
vmaw->co_writer = qemu_coroutine_self();
- aio_set_fd_handler(qemu_get_aio_context(), vmaw->fd, false, NULL, vma_co_continue_write, vmaw);
-
- DPRINTF("vma_co_write wait until writable\n");
- qemu_coroutine_yield();
- DPRINTF("vma_co_write starting %zd\n", bytes);
-
while (done < bytes) {
+ aio_set_fd_handler(qemu_get_aio_context(), vmaw->fd, false, NULL, vma_co_continue_write, vmaw);
+ qemu_coroutine_yield();
+ aio_set_fd_handler(qemu_get_aio_context(), vmaw->fd, false, NULL, NULL, NULL);
+ if (vmaw->status < 0) {
+ DPRINTF("vma_queue_write detected canceled backup\n");
+ done = -1;
+ break;
+ }
ret = write(vmaw->fd, buf + done, bytes - done);
if (ret > 0) {
done += ret;
- DPRINTF("vma_co_write written %zd %zd\n", done, ret);
+ DPRINTF("vma_queue_write written %zd %zd\n", done, ret);
} else if (ret < 0) {
if (errno == EAGAIN || errno == EWOULDBLOCK) {
- DPRINTF("vma_co_write yield %zd\n", done);
- qemu_coroutine_yield();
- DPRINTF("vma_co_write restart %zd\n", done);
- } else {
- vma_writer_set_error(vmaw, "vma_co_write write error - %s",
+ /* try again */
+ } else {
+ vma_writer_set_error(vmaw, "vma_queue_write: write error - %s",
g_strerror(errno));
done = -1; /* always return failure for partial writes */
break;
@@ -258,102 +251,9 @@ vma_co_write(VmaWriter *vmaw, const void *buf, size_t bytes)
}
}
- aio_set_fd_handler(qemu_get_aio_context(), vmaw->fd, false, NULL, NULL, NULL);
-
vmaw->co_writer = NULL;
-
- qemu_co_mutex_unlock(&vmaw->writer_lock);
-
- DPRINTF("vma_co_write leave %zd\n", done);
- return done;
-}
-
-static void coroutine_fn vma_co_writer_task(void *opaque)
-{
- VmaAIOCB *cb = opaque;
-
- DPRINTF("vma_co_writer_task start\n");
-
- int64_t done = vma_co_write(cb->vmaw, cb->buffer, cb->bytes);
- DPRINTF("vma_co_writer_task write done %zd\n", done);
-
- if (done != cb->bytes) {
- DPRINTF("vma_co_writer_task failed write %zd %zd", cb->bytes, done);
- vma_writer_set_error(cb->vmaw, "vma_co_writer_task failed write %zd",
- done);
- }
-
- cb->bytes = 0;
-
- qemu_co_queue_next(&cb->vmaw->wqueue);
-
- DPRINTF("vma_co_writer_task end\n");
-}
-
-static void coroutine_fn vma_queue_flush(VmaWriter *vmaw)
-{
- DPRINTF("vma_queue_flush enter\n");
-
- assert(vmaw);
-
- while (1) {
- int i;
- VmaAIOCB *cb = NULL;
- for (i = 0; i < WRITE_BUFFERS; i++) {
- if (vmaw->aiocbs[i]->bytes) {
- cb = vmaw->aiocbs[i];
- DPRINTF("FOUND USED AIO BUFFER %d %zd\n", i,
- vmaw->aiocbs[i]->bytes);
- break;
- }
- }
- if (!cb) {
- break;
- }
- qemu_co_queue_wait(&vmaw->wqueue);
- }
-
- DPRINTF("vma_queue_flush leave\n");
-}
-
-/**
- * NOTE: pipe buffer size in only 4096 bytes on linux (see 'ulimit -a')
- * So we need to create a coroutione to allow 'parallel' execution.
- */
-static ssize_t coroutine_fn
-vma_queue_write(VmaWriter *vmaw, const void *buf, size_t bytes)
-{
- DPRINTF("vma_queue_write enter %zd\n", bytes);
-
- assert(vmaw);
- assert(buf);
- assert(bytes <= VMA_MAX_EXTENT_SIZE);
-
- VmaAIOCB *cb = NULL;
- while (!cb) {
- int i;
- for (i = 0; i < WRITE_BUFFERS; i++) {
- if (!vmaw->aiocbs[i]->bytes) {
- cb = vmaw->aiocbs[i];
- break;
- }
- }
- if (!cb) {
- qemu_co_queue_wait(&vmaw->wqueue);
- }
- }
-
- memcpy(cb->buffer, buf, bytes);
- cb->bytes = bytes;
- cb->vmaw = vmaw;
-
- DPRINTF("vma_queue_write start %zd\n", bytes);
- cb->co = qemu_coroutine_create(vma_co_writer_task);
- qemu_coroutine_enter(cb->co, cb);
-
- DPRINTF("vma_queue_write leave\n");
-
- return bytes;
+
+ return (done == bytes) ? bytes : -1;
}
VmaWriter *vma_writer_create(const char *filename, uuid_t uuid, Error **errp)
@@ -420,20 +320,16 @@ VmaWriter *vma_writer_create(const char *filename, uuid_t uuid, Error **errp)
}
/* we use O_DIRECT, so we need to align IO buffers */
- int i;
- for (i = 0; i < WRITE_BUFFERS; i++) {
- vmaw->aiocbs[i] = qemu_memalign(512, sizeof(VmaAIOCB));
- memset(vmaw->aiocbs[i], 0, sizeof(VmaAIOCB));
- }
+
+ vmaw->outbuf = qemu_memalign(512, VMA_MAX_EXTENT_SIZE);
+ vmaw->headerbuf = qemu_memalign(512, HEADERBUF_SIZE);
vmaw->outbuf_count = 0;
vmaw->outbuf_pos = VMA_EXTENT_HEADER_SIZE;
vmaw->header_blob_table_pos = 1; /* start at pos 1 */
- qemu_co_mutex_init(&vmaw->writer_lock);
qemu_co_mutex_init(&vmaw->flush_lock);
- qemu_co_queue_init(&vmaw->wqueue);
uuid_copy(vmaw->uuid, uuid);
@@ -460,8 +356,7 @@ err:
static int coroutine_fn vma_write_header(VmaWriter *vmaw)
{
assert(vmaw);
- int header_clusters = 8;
- char buf[65536*header_clusters];
+ unsigned char *buf = vmaw->headerbuf;
VmaHeader *head = (VmaHeader *)buf;
int i;
@@ -472,7 +367,7 @@ static int coroutine_fn vma_write_header(VmaWriter *vmaw)
return vmaw->status;
}
- memset(buf, 0, sizeof(buf));
+ memset(buf, 0, HEADERBUF_SIZE);
head->magic = VMA_MAGIC;
head->version = GUINT32_TO_BE(1); /* v1 */
@@ -507,7 +402,7 @@ static int coroutine_fn vma_write_header(VmaWriter *vmaw)
uint32_t header_size = sizeof(VmaHeader) + vmaw->header_blob_table_size;
head->header_size = GUINT32_TO_BE(header_size);
- if (header_size > sizeof(buf)) {
+ if (header_size > HEADERBUF_SIZE) {
return -1; /* just to be sure */
}
@@ -805,13 +700,7 @@ int vma_writer_close(VmaWriter *vmaw, Error **errp)
int i;
- vma_queue_flush(vmaw);
-
- /* this should not happen - just to be sure */
- while (!qemu_co_queue_empty(&vmaw->wqueue)) {
- DPRINTF("vma_writer_close wait\n");
- co_aio_sleep_ns(qemu_get_aio_context(), QEMU_CLOCK_REALTIME, 1000000);
- }
+ assert(vmaw->co_writer == NULL);
if (vmaw->cmd) {
if (pclose(vmaw->cmd) < 0) {
@@ -869,9 +758,5 @@ void vma_writer_destroy(VmaWriter *vmaw)
g_checksum_free(vmaw->md5csum);
}
- for (i = 0; i < WRITE_BUFFERS; i++) {
- free(vmaw->aiocbs[i]);
- }
-
g_free(vmaw);
}
--
2.1.4
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