From: Dietmar Maurer Date: Thu, 27 Mar 2014 11:20:19 +0000 (+0100) Subject: backup: remove async queue (avoid segmentation fault) X-Git-Url: https://git.proxmox.com/?p=pve-qemu-kvm.git;a=commitdiff_plain;h=9adb8c8d528f84de431d1ce04911b0c92d7ca651 backup: remove async queue (avoid segmentation fault) --- diff --git a/debian/patches/backup-vma-remove-async-queue.patch b/debian/patches/backup-vma-remove-async-queue.patch new file mode 100644 index 0000000..6f2dc0f --- /dev/null +++ b/debian/patches/backup-vma-remove-async-queue.patch @@ -0,0 +1,309 @@ +We do not gain much speed here, so I removed the whole queue code +to make things simpler. + +Also, previous code produced segmentation faults in qemu_co_mutex_lock(). + +Index: new/vma-writer.c +=================================================================== +--- new.orig/vma-writer.c 2014-03-27 08:59:26.000000000 +0100 ++++ new/vma-writer.c 2014-03-27 12:09:24.000000000 +0100 +@@ -33,14 +33,8 @@ + 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; +@@ -52,16 +46,14 @@ + 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; + +@@ -222,38 +214,39 @@ + } + + 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(); + +- qemu_aio_set_fd_handler(vmaw->fd, 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) { ++ qemu_aio_set_fd_handler(vmaw->fd, NULL, vma_co_continue_write, vmaw); ++ qemu_coroutine_yield(); ++ qemu_aio_set_fd_handler(vmaw->fd, 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; +@@ -263,102 +256,9 @@ + } + } + +- qemu_aio_set_fd_handler(vmaw->fd, 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) +@@ -425,20 +325,16 @@ + } + + /* 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); + +@@ -465,8 +361,7 @@ + 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; +@@ -477,7 +372,7 @@ + return vmaw->status; + } + +- memset(buf, 0, sizeof(buf)); ++ memset(buf, 0, HEADERBUF_SIZE); + + head->magic = VMA_MAGIC; + head->version = GUINT32_TO_BE(1); /* v1 */ +@@ -512,7 +407,7 @@ + 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 */ + } + +@@ -810,13 +705,7 @@ + + 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_sleep_ns(QEMU_CLOCK_REALTIME, 1000000); +- } ++ assert(vmaw->co_writer == NULL); + + if (vmaw->cmd) { + if (pclose(vmaw->cmd) < 0) { +@@ -874,9 +763,5 @@ + g_checksum_free(vmaw->md5csum); + } + +- for (i = 0; i < WRITE_BUFFERS; i++) { +- free(vmaw->aiocbs[i]); +- } +- + g_free(vmaw); + } +Index: new/blockdev.c +=================================================================== +--- new.orig/blockdev.c 2014-03-27 12:10:25.000000000 +0100 ++++ new/blockdev.c 2014-03-27 12:10:47.000000000 +0100 +@@ -1875,6 +1875,11 @@ + 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(); + +@@ -1887,6 +1892,7 @@ + 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/debian/patches/series b/debian/patches/series index 05c488e..c3080e7 100644 --- a/debian/patches/series +++ b/debian/patches/series @@ -21,5 +21,6 @@ backup-add-pve-monitor-commands.patch backup-add-dir-format.patch backup-do-not-return-errors-in-dump-callback.patch backup-vma-correctly-propagate-error.patch +backup-vma-remove-async-queue.patch internal-snapshot-async.patch disable-efi-enable-pxe-roms.patch