1028 lines
32 KiB
C
1028 lines
32 KiB
C
/*
|
||
* block_copy API
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||
*
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* Copyright (C) 2013 Proxmox Server Solutions
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* Copyright (c) 2019 Virtuozzo International GmbH.
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*
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* Authors:
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* Dietmar Maurer (dietmar@proxmox.com)
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* Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
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*
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* This work is licensed under the terms of the GNU GPL, version 2 or later.
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* See the COPYING file in the top-level directory.
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*/
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#include "qemu/osdep.h"
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#include "trace.h"
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#include "qapi/error.h"
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#include "block/block-copy.h"
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#include "block/reqlist.h"
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#include "sysemu/block-backend.h"
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#include "qemu/units.h"
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#include "qemu/coroutine.h"
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#include "block/aio_task.h"
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#include "qemu/error-report.h"
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#include "qemu/memalign.h"
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#define BLOCK_COPY_MAX_COPY_RANGE (16 * MiB)
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#define BLOCK_COPY_MAX_BUFFER (1 * MiB)
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#define BLOCK_COPY_MAX_MEM (128 * MiB)
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#define BLOCK_COPY_MAX_WORKERS 64
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#define BLOCK_COPY_SLICE_TIME 100000000ULL /* ns */
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#define BLOCK_COPY_CLUSTER_SIZE_DEFAULT (1 << 16)
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typedef enum {
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COPY_READ_WRITE_CLUSTER,
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COPY_READ_WRITE,
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COPY_WRITE_ZEROES,
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COPY_RANGE_SMALL,
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COPY_RANGE_FULL
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} BlockCopyMethod;
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static coroutine_fn int block_copy_task_entry(AioTask *task);
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typedef struct BlockCopyCallState {
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/* Fields initialized in block_copy_async() and never changed. */
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BlockCopyState *s;
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int64_t offset;
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int64_t bytes;
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int max_workers;
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int64_t max_chunk;
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bool ignore_ratelimit;
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BlockCopyAsyncCallbackFunc cb;
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void *cb_opaque;
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/* Coroutine where async block-copy is running */
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Coroutine *co;
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/* Fields whose state changes throughout the execution */
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bool finished; /* atomic */
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QemuCoSleep sleep; /* TODO: protect API with a lock */
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bool cancelled; /* atomic */
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/* To reference all call states from BlockCopyState */
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QLIST_ENTRY(BlockCopyCallState) list;
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/*
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* Fields that report information about return values and erros.
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* Protected by lock in BlockCopyState.
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*/
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bool error_is_read;
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/*
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* @ret is set concurrently by tasks under mutex. Only set once by first
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* failed task (and untouched if no task failed).
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* After finishing (call_state->finished is true), it is not modified
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* anymore and may be safely read without mutex.
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*/
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int ret;
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} BlockCopyCallState;
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typedef struct BlockCopyTask {
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AioTask task;
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/*
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* Fields initialized in block_copy_task_create()
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* and never changed.
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*/
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BlockCopyState *s;
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BlockCopyCallState *call_state;
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/*
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* @method can also be set again in the while loop of
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* block_copy_dirty_clusters(), but it is never accessed concurrently
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* because the only other function that reads it is
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* block_copy_task_entry() and it is invoked afterwards in the same
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* iteration.
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*/
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BlockCopyMethod method;
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/*
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* Generally, req is protected by lock in BlockCopyState, Still req.offset
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* is only set on task creation, so may be read concurrently after creation.
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* req.bytes is changed at most once, and need only protecting the case of
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* parallel read while updating @bytes value in block_copy_task_shrink().
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*/
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BlockReq req;
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} BlockCopyTask;
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static int64_t task_end(BlockCopyTask *task)
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{
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return task->req.offset + task->req.bytes;
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}
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typedef struct BlockCopyState {
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/*
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* BdrvChild objects are not owned or managed by block-copy. They are
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* provided by block-copy user and user is responsible for appropriate
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* permissions on these children.
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*/
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BdrvChild *source;
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BdrvChild *target;
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/*
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* Fields initialized in block_copy_state_new()
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* and never changed.
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*/
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int64_t cluster_size;
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int64_t max_transfer;
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uint64_t len;
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BdrvRequestFlags write_flags;
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/*
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* Fields whose state changes throughout the execution
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* Protected by lock.
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*/
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CoMutex lock;
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int64_t in_flight_bytes;
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BlockCopyMethod method;
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BlockReqList reqs;
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QLIST_HEAD(, BlockCopyCallState) calls;
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/*
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* skip_unallocated:
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*
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* Used by sync=top jobs, which first scan the source node for unallocated
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* areas and clear them in the copy_bitmap. During this process, the bitmap
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* is thus not fully initialized: It may still have bits set for areas that
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* are unallocated and should actually not be copied.
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*
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* This is indicated by skip_unallocated.
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*
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* In this case, block_copy() will query the source’s allocation status,
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* skip unallocated regions, clear them in the copy_bitmap, and invoke
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* block_copy_reset_unallocated() every time it does.
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*/
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bool skip_unallocated; /* atomic */
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/* State fields that use a thread-safe API */
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BdrvDirtyBitmap *copy_bitmap;
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ProgressMeter *progress;
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SharedResource *mem;
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RateLimit rate_limit;
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} BlockCopyState;
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/* Called with lock held */
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static int64_t block_copy_chunk_size(BlockCopyState *s)
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{
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switch (s->method) {
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case COPY_READ_WRITE_CLUSTER:
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return s->cluster_size;
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case COPY_READ_WRITE:
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case COPY_RANGE_SMALL:
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return MIN(MAX(s->cluster_size, BLOCK_COPY_MAX_BUFFER),
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s->max_transfer);
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case COPY_RANGE_FULL:
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return MIN(MAX(s->cluster_size, BLOCK_COPY_MAX_COPY_RANGE),
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s->max_transfer);
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default:
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/* Cannot have COPY_WRITE_ZEROES here. */
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abort();
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}
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}
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/*
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* Search for the first dirty area in offset/bytes range and create task at
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* the beginning of it.
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*/
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static coroutine_fn BlockCopyTask *
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block_copy_task_create(BlockCopyState *s, BlockCopyCallState *call_state,
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int64_t offset, int64_t bytes)
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{
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BlockCopyTask *task;
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int64_t max_chunk;
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QEMU_LOCK_GUARD(&s->lock);
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max_chunk = MIN_NON_ZERO(block_copy_chunk_size(s), call_state->max_chunk);
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if (!bdrv_dirty_bitmap_next_dirty_area(s->copy_bitmap,
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offset, offset + bytes,
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max_chunk, &offset, &bytes))
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{
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return NULL;
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}
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assert(QEMU_IS_ALIGNED(offset, s->cluster_size));
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bytes = QEMU_ALIGN_UP(bytes, s->cluster_size);
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/* region is dirty, so no existent tasks possible in it */
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assert(!reqlist_find_conflict(&s->reqs, offset, bytes));
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bdrv_reset_dirty_bitmap(s->copy_bitmap, offset, bytes);
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s->in_flight_bytes += bytes;
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task = g_new(BlockCopyTask, 1);
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*task = (BlockCopyTask) {
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.task.func = block_copy_task_entry,
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.s = s,
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.call_state = call_state,
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.method = s->method,
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};
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reqlist_init_req(&s->reqs, &task->req, offset, bytes);
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return task;
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}
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/*
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* block_copy_task_shrink
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*
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* Drop the tail of the task to be handled later. Set dirty bits back and
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* wake up all tasks waiting for us (may be some of them are not intersecting
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* with shrunk task)
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*/
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static void coroutine_fn block_copy_task_shrink(BlockCopyTask *task,
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int64_t new_bytes)
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{
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QEMU_LOCK_GUARD(&task->s->lock);
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if (new_bytes == task->req.bytes) {
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return;
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}
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assert(new_bytes > 0 && new_bytes < task->req.bytes);
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task->s->in_flight_bytes -= task->req.bytes - new_bytes;
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bdrv_set_dirty_bitmap(task->s->copy_bitmap,
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task->req.offset + new_bytes,
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task->req.bytes - new_bytes);
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reqlist_shrink_req(&task->req, new_bytes);
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}
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static void coroutine_fn block_copy_task_end(BlockCopyTask *task, int ret)
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{
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QEMU_LOCK_GUARD(&task->s->lock);
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task->s->in_flight_bytes -= task->req.bytes;
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if (ret < 0) {
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bdrv_set_dirty_bitmap(task->s->copy_bitmap, task->req.offset,
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task->req.bytes);
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}
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if (task->s->progress) {
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progress_set_remaining(task->s->progress,
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bdrv_get_dirty_count(task->s->copy_bitmap) +
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task->s->in_flight_bytes);
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}
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reqlist_remove_req(&task->req);
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}
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void block_copy_state_free(BlockCopyState *s)
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{
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if (!s) {
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return;
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}
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ratelimit_destroy(&s->rate_limit);
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bdrv_release_dirty_bitmap(s->copy_bitmap);
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shres_destroy(s->mem);
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g_free(s);
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}
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static uint32_t block_copy_max_transfer(BdrvChild *source, BdrvChild *target)
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{
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return MIN_NON_ZERO(INT_MAX,
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MIN_NON_ZERO(source->bs->bl.max_transfer,
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target->bs->bl.max_transfer));
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}
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void block_copy_set_copy_opts(BlockCopyState *s, bool use_copy_range,
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bool compress)
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{
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/* Keep BDRV_REQ_SERIALISING set (or not set) in block_copy_state_new() */
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s->write_flags = (s->write_flags & BDRV_REQ_SERIALISING) |
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(compress ? BDRV_REQ_WRITE_COMPRESSED : 0);
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if (s->max_transfer < s->cluster_size) {
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/*
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* copy_range does not respect max_transfer. We don't want to bother
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* with requests smaller than block-copy cluster size, so fallback to
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* buffered copying (read and write respect max_transfer on their
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* behalf).
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*/
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s->method = COPY_READ_WRITE_CLUSTER;
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} else if (compress) {
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/* Compression supports only cluster-size writes and no copy-range. */
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s->method = COPY_READ_WRITE_CLUSTER;
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} else {
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/*
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* If copy range enabled, start with COPY_RANGE_SMALL, until first
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* successful copy_range (look at block_copy_do_copy).
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*/
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s->method = use_copy_range ? COPY_RANGE_SMALL : COPY_READ_WRITE;
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}
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}
|
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static int64_t block_copy_calculate_cluster_size(BlockDriverState *target,
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Error **errp)
|
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{
|
||
int ret;
|
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BlockDriverInfo bdi;
|
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bool target_does_cow = bdrv_backing_chain_next(target);
|
||
|
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/*
|
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* If there is no backing file on the target, we cannot rely on COW if our
|
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* backup cluster size is smaller than the target cluster size. Even for
|
||
* targets with a backing file, try to avoid COW if possible.
|
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*/
|
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ret = bdrv_get_info(target, &bdi);
|
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if (ret == -ENOTSUP && !target_does_cow) {
|
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/* Cluster size is not defined */
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warn_report("The target block device doesn't provide "
|
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"information about the block size and it doesn't have a "
|
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"backing file. The default block size of %u bytes is "
|
||
"used. If the actual block size of the target exceeds "
|
||
"this default, the backup may be unusable",
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BLOCK_COPY_CLUSTER_SIZE_DEFAULT);
|
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return BLOCK_COPY_CLUSTER_SIZE_DEFAULT;
|
||
} else if (ret < 0 && !target_does_cow) {
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error_setg_errno(errp, -ret,
|
||
"Couldn't determine the cluster size of the target image, "
|
||
"which has no backing file");
|
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error_append_hint(errp,
|
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"Aborting, since this may create an unusable destination image\n");
|
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return ret;
|
||
} else if (ret < 0 && target_does_cow) {
|
||
/* Not fatal; just trudge on ahead. */
|
||
return BLOCK_COPY_CLUSTER_SIZE_DEFAULT;
|
||
}
|
||
|
||
return MAX(BLOCK_COPY_CLUSTER_SIZE_DEFAULT, bdi.cluster_size);
|
||
}
|
||
|
||
BlockCopyState *block_copy_state_new(BdrvChild *source, BdrvChild *target,
|
||
const BdrvDirtyBitmap *bitmap,
|
||
Error **errp)
|
||
{
|
||
ERRP_GUARD();
|
||
BlockCopyState *s;
|
||
int64_t cluster_size;
|
||
BdrvDirtyBitmap *copy_bitmap;
|
||
bool is_fleecing;
|
||
|
||
cluster_size = block_copy_calculate_cluster_size(target->bs, errp);
|
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if (cluster_size < 0) {
|
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return NULL;
|
||
}
|
||
|
||
copy_bitmap = bdrv_create_dirty_bitmap(source->bs, cluster_size, NULL,
|
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errp);
|
||
if (!copy_bitmap) {
|
||
return NULL;
|
||
}
|
||
bdrv_disable_dirty_bitmap(copy_bitmap);
|
||
if (bitmap) {
|
||
if (!bdrv_merge_dirty_bitmap(copy_bitmap, bitmap, NULL, errp)) {
|
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error_prepend(errp, "Failed to merge bitmap '%s' to internal "
|
||
"copy-bitmap: ", bdrv_dirty_bitmap_name(bitmap));
|
||
bdrv_release_dirty_bitmap(copy_bitmap);
|
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return NULL;
|
||
}
|
||
} else {
|
||
bdrv_set_dirty_bitmap(copy_bitmap, 0,
|
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bdrv_dirty_bitmap_size(copy_bitmap));
|
||
}
|
||
|
||
/*
|
||
* If source is in backing chain of target assume that target is going to be
|
||
* used for "image fleecing", i.e. it should represent a kind of snapshot of
|
||
* source at backup-start point in time. And target is going to be read by
|
||
* somebody (for example, used as NBD export) during backup job.
|
||
*
|
||
* In this case, we need to add BDRV_REQ_SERIALISING write flag to avoid
|
||
* intersection of backup writes and third party reads from target,
|
||
* otherwise reading from target we may occasionally read already updated by
|
||
* guest data.
|
||
*
|
||
* For more information see commit f8d59dfb40bb and test
|
||
* tests/qemu-iotests/222
|
||
*/
|
||
is_fleecing = bdrv_chain_contains(target->bs, source->bs);
|
||
|
||
s = g_new(BlockCopyState, 1);
|
||
*s = (BlockCopyState) {
|
||
.source = source,
|
||
.target = target,
|
||
.copy_bitmap = copy_bitmap,
|
||
.cluster_size = cluster_size,
|
||
.len = bdrv_dirty_bitmap_size(copy_bitmap),
|
||
.write_flags = (is_fleecing ? BDRV_REQ_SERIALISING : 0),
|
||
.mem = shres_create(BLOCK_COPY_MAX_MEM),
|
||
.max_transfer = QEMU_ALIGN_DOWN(
|
||
block_copy_max_transfer(source, target),
|
||
cluster_size),
|
||
};
|
||
|
||
block_copy_set_copy_opts(s, false, false);
|
||
|
||
ratelimit_init(&s->rate_limit);
|
||
qemu_co_mutex_init(&s->lock);
|
||
QLIST_INIT(&s->reqs);
|
||
QLIST_INIT(&s->calls);
|
||
|
||
return s;
|
||
}
|
||
|
||
/* Only set before running the job, no need for locking. */
|
||
void block_copy_set_progress_meter(BlockCopyState *s, ProgressMeter *pm)
|
||
{
|
||
s->progress = pm;
|
||
}
|
||
|
||
/*
|
||
* Takes ownership of @task
|
||
*
|
||
* If pool is NULL directly run the task, otherwise schedule it into the pool.
|
||
*
|
||
* Returns: task.func return code if pool is NULL
|
||
* otherwise -ECANCELED if pool status is bad
|
||
* otherwise 0 (successfully scheduled)
|
||
*/
|
||
static coroutine_fn int block_copy_task_run(AioTaskPool *pool,
|
||
BlockCopyTask *task)
|
||
{
|
||
if (!pool) {
|
||
int ret = task->task.func(&task->task);
|
||
|
||
g_free(task);
|
||
return ret;
|
||
}
|
||
|
||
aio_task_pool_wait_slot(pool);
|
||
if (aio_task_pool_status(pool) < 0) {
|
||
co_put_to_shres(task->s->mem, task->req.bytes);
|
||
block_copy_task_end(task, -ECANCELED);
|
||
g_free(task);
|
||
return -ECANCELED;
|
||
}
|
||
|
||
aio_task_pool_start_task(pool, &task->task);
|
||
|
||
return 0;
|
||
}
|
||
|
||
/*
|
||
* block_copy_do_copy
|
||
*
|
||
* Do copy of cluster-aligned chunk. Requested region is allowed to exceed
|
||
* s->len only to cover last cluster when s->len is not aligned to clusters.
|
||
*
|
||
* No sync here: nor bitmap neighter intersecting requests handling, only copy.
|
||
*
|
||
* @method is an in-out argument, so that copy_range can be either extended to
|
||
* a full-size buffer or disabled if the copy_range attempt fails. The output
|
||
* value of @method should be used for subsequent tasks.
|
||
* Returns 0 on success.
|
||
*/
|
||
static int coroutine_fn block_copy_do_copy(BlockCopyState *s,
|
||
int64_t offset, int64_t bytes,
|
||
BlockCopyMethod *method,
|
||
bool *error_is_read)
|
||
{
|
||
int ret;
|
||
int64_t nbytes = MIN(offset + bytes, s->len) - offset;
|
||
void *bounce_buffer = NULL;
|
||
|
||
assert(offset >= 0 && bytes > 0 && INT64_MAX - offset >= bytes);
|
||
assert(QEMU_IS_ALIGNED(offset, s->cluster_size));
|
||
assert(QEMU_IS_ALIGNED(bytes, s->cluster_size));
|
||
assert(offset < s->len);
|
||
assert(offset + bytes <= s->len ||
|
||
offset + bytes == QEMU_ALIGN_UP(s->len, s->cluster_size));
|
||
assert(nbytes < INT_MAX);
|
||
|
||
switch (*method) {
|
||
case COPY_WRITE_ZEROES:
|
||
ret = bdrv_co_pwrite_zeroes(s->target, offset, nbytes, s->write_flags &
|
||
~BDRV_REQ_WRITE_COMPRESSED);
|
||
if (ret < 0) {
|
||
trace_block_copy_write_zeroes_fail(s, offset, ret);
|
||
*error_is_read = false;
|
||
}
|
||
return ret;
|
||
|
||
case COPY_RANGE_SMALL:
|
||
case COPY_RANGE_FULL:
|
||
ret = bdrv_co_copy_range(s->source, offset, s->target, offset, nbytes,
|
||
0, s->write_flags);
|
||
if (ret >= 0) {
|
||
/* Successful copy-range, increase chunk size. */
|
||
*method = COPY_RANGE_FULL;
|
||
return 0;
|
||
}
|
||
|
||
trace_block_copy_copy_range_fail(s, offset, ret);
|
||
*method = COPY_READ_WRITE;
|
||
/* Fall through to read+write with allocated buffer */
|
||
|
||
case COPY_READ_WRITE_CLUSTER:
|
||
case COPY_READ_WRITE:
|
||
/*
|
||
* In case of failed copy_range request above, we may proceed with
|
||
* buffered request larger than BLOCK_COPY_MAX_BUFFER.
|
||
* Still, further requests will be properly limited, so don't care too
|
||
* much. Moreover the most likely case (copy_range is unsupported for
|
||
* the configuration, so the very first copy_range request fails)
|
||
* is handled by setting large copy_size only after first successful
|
||
* copy_range.
|
||
*/
|
||
|
||
bounce_buffer = qemu_blockalign(s->source->bs, nbytes);
|
||
|
||
ret = bdrv_co_pread(s->source, offset, nbytes, bounce_buffer, 0);
|
||
if (ret < 0) {
|
||
trace_block_copy_read_fail(s, offset, ret);
|
||
*error_is_read = true;
|
||
goto out;
|
||
}
|
||
|
||
ret = bdrv_co_pwrite(s->target, offset, nbytes, bounce_buffer,
|
||
s->write_flags);
|
||
if (ret < 0) {
|
||
trace_block_copy_write_fail(s, offset, ret);
|
||
*error_is_read = false;
|
||
goto out;
|
||
}
|
||
|
||
out:
|
||
qemu_vfree(bounce_buffer);
|
||
break;
|
||
|
||
default:
|
||
abort();
|
||
}
|
||
|
||
return ret;
|
||
}
|
||
|
||
static coroutine_fn int block_copy_task_entry(AioTask *task)
|
||
{
|
||
BlockCopyTask *t = container_of(task, BlockCopyTask, task);
|
||
BlockCopyState *s = t->s;
|
||
bool error_is_read = false;
|
||
BlockCopyMethod method = t->method;
|
||
int ret;
|
||
|
||
ret = block_copy_do_copy(s, t->req.offset, t->req.bytes, &method,
|
||
&error_is_read);
|
||
|
||
WITH_QEMU_LOCK_GUARD(&s->lock) {
|
||
if (s->method == t->method) {
|
||
s->method = method;
|
||
}
|
||
|
||
if (ret < 0) {
|
||
if (!t->call_state->ret) {
|
||
t->call_state->ret = ret;
|
||
t->call_state->error_is_read = error_is_read;
|
||
}
|
||
} else if (s->progress) {
|
||
progress_work_done(s->progress, t->req.bytes);
|
||
}
|
||
}
|
||
co_put_to_shres(s->mem, t->req.bytes);
|
||
block_copy_task_end(t, ret);
|
||
|
||
return ret;
|
||
}
|
||
|
||
static int block_copy_block_status(BlockCopyState *s, int64_t offset,
|
||
int64_t bytes, int64_t *pnum)
|
||
{
|
||
int64_t num;
|
||
BlockDriverState *base;
|
||
int ret;
|
||
|
||
if (qatomic_read(&s->skip_unallocated)) {
|
||
base = bdrv_backing_chain_next(s->source->bs);
|
||
} else {
|
||
base = NULL;
|
||
}
|
||
|
||
ret = bdrv_block_status_above(s->source->bs, base, offset, bytes, &num,
|
||
NULL, NULL);
|
||
if (ret < 0 || num < s->cluster_size) {
|
||
/*
|
||
* On error or if failed to obtain large enough chunk just fallback to
|
||
* copy one cluster.
|
||
*/
|
||
num = s->cluster_size;
|
||
ret = BDRV_BLOCK_ALLOCATED | BDRV_BLOCK_DATA;
|
||
} else if (offset + num == s->len) {
|
||
num = QEMU_ALIGN_UP(num, s->cluster_size);
|
||
} else {
|
||
num = QEMU_ALIGN_DOWN(num, s->cluster_size);
|
||
}
|
||
|
||
*pnum = num;
|
||
return ret;
|
||
}
|
||
|
||
/*
|
||
* Check if the cluster starting at offset is allocated or not.
|
||
* return via pnum the number of contiguous clusters sharing this allocation.
|
||
*/
|
||
static int block_copy_is_cluster_allocated(BlockCopyState *s, int64_t offset,
|
||
int64_t *pnum)
|
||
{
|
||
BlockDriverState *bs = s->source->bs;
|
||
int64_t count, total_count = 0;
|
||
int64_t bytes = s->len - offset;
|
||
int ret;
|
||
|
||
assert(QEMU_IS_ALIGNED(offset, s->cluster_size));
|
||
|
||
while (true) {
|
||
ret = bdrv_is_allocated(bs, offset, bytes, &count);
|
||
if (ret < 0) {
|
||
return ret;
|
||
}
|
||
|
||
total_count += count;
|
||
|
||
if (ret || count == 0) {
|
||
/*
|
||
* ret: partial segment(s) are considered allocated.
|
||
* otherwise: unallocated tail is treated as an entire segment.
|
||
*/
|
||
*pnum = DIV_ROUND_UP(total_count, s->cluster_size);
|
||
return ret;
|
||
}
|
||
|
||
/* Unallocated segment(s) with uncertain following segment(s) */
|
||
if (total_count >= s->cluster_size) {
|
||
*pnum = total_count / s->cluster_size;
|
||
return 0;
|
||
}
|
||
|
||
offset += count;
|
||
bytes -= count;
|
||
}
|
||
}
|
||
|
||
void block_copy_reset(BlockCopyState *s, int64_t offset, int64_t bytes)
|
||
{
|
||
QEMU_LOCK_GUARD(&s->lock);
|
||
|
||
bdrv_reset_dirty_bitmap(s->copy_bitmap, offset, bytes);
|
||
if (s->progress) {
|
||
progress_set_remaining(s->progress,
|
||
bdrv_get_dirty_count(s->copy_bitmap) +
|
||
s->in_flight_bytes);
|
||
}
|
||
}
|
||
|
||
/*
|
||
* Reset bits in copy_bitmap starting at offset if they represent unallocated
|
||
* data in the image. May reset subsequent contiguous bits.
|
||
* @return 0 when the cluster at @offset was unallocated,
|
||
* 1 otherwise, and -ret on error.
|
||
*/
|
||
int64_t block_copy_reset_unallocated(BlockCopyState *s,
|
||
int64_t offset, int64_t *count)
|
||
{
|
||
int ret;
|
||
int64_t clusters, bytes;
|
||
|
||
ret = block_copy_is_cluster_allocated(s, offset, &clusters);
|
||
if (ret < 0) {
|
||
return ret;
|
||
}
|
||
|
||
bytes = clusters * s->cluster_size;
|
||
|
||
if (!ret) {
|
||
block_copy_reset(s, offset, bytes);
|
||
}
|
||
|
||
*count = bytes;
|
||
return ret;
|
||
}
|
||
|
||
/*
|
||
* block_copy_dirty_clusters
|
||
*
|
||
* Copy dirty clusters in @offset/@bytes range.
|
||
* Returns 1 if dirty clusters found and successfully copied, 0 if no dirty
|
||
* clusters found and -errno on failure.
|
||
*/
|
||
static int coroutine_fn
|
||
block_copy_dirty_clusters(BlockCopyCallState *call_state)
|
||
{
|
||
BlockCopyState *s = call_state->s;
|
||
int64_t offset = call_state->offset;
|
||
int64_t bytes = call_state->bytes;
|
||
|
||
int ret = 0;
|
||
bool found_dirty = false;
|
||
int64_t end = offset + bytes;
|
||
AioTaskPool *aio = NULL;
|
||
|
||
/*
|
||
* block_copy() user is responsible for keeping source and target in same
|
||
* aio context
|
||
*/
|
||
assert(bdrv_get_aio_context(s->source->bs) ==
|
||
bdrv_get_aio_context(s->target->bs));
|
||
|
||
assert(QEMU_IS_ALIGNED(offset, s->cluster_size));
|
||
assert(QEMU_IS_ALIGNED(bytes, s->cluster_size));
|
||
|
||
while (bytes && aio_task_pool_status(aio) == 0 &&
|
||
!qatomic_read(&call_state->cancelled)) {
|
||
BlockCopyTask *task;
|
||
int64_t status_bytes;
|
||
|
||
task = block_copy_task_create(s, call_state, offset, bytes);
|
||
if (!task) {
|
||
/* No more dirty bits in the bitmap */
|
||
trace_block_copy_skip_range(s, offset, bytes);
|
||
break;
|
||
}
|
||
if (task->req.offset > offset) {
|
||
trace_block_copy_skip_range(s, offset, task->req.offset - offset);
|
||
}
|
||
|
||
found_dirty = true;
|
||
|
||
ret = block_copy_block_status(s, task->req.offset, task->req.bytes,
|
||
&status_bytes);
|
||
assert(ret >= 0); /* never fail */
|
||
if (status_bytes < task->req.bytes) {
|
||
block_copy_task_shrink(task, status_bytes);
|
||
}
|
||
if (qatomic_read(&s->skip_unallocated) &&
|
||
!(ret & BDRV_BLOCK_ALLOCATED)) {
|
||
block_copy_task_end(task, 0);
|
||
trace_block_copy_skip_range(s, task->req.offset, task->req.bytes);
|
||
offset = task_end(task);
|
||
bytes = end - offset;
|
||
g_free(task);
|
||
continue;
|
||
}
|
||
if (ret & BDRV_BLOCK_ZERO) {
|
||
task->method = COPY_WRITE_ZEROES;
|
||
}
|
||
|
||
if (!call_state->ignore_ratelimit) {
|
||
uint64_t ns = ratelimit_calculate_delay(&s->rate_limit, 0);
|
||
if (ns > 0) {
|
||
block_copy_task_end(task, -EAGAIN);
|
||
g_free(task);
|
||
qemu_co_sleep_ns_wakeable(&call_state->sleep,
|
||
QEMU_CLOCK_REALTIME, ns);
|
||
continue;
|
||
}
|
||
}
|
||
|
||
ratelimit_calculate_delay(&s->rate_limit, task->req.bytes);
|
||
|
||
trace_block_copy_process(s, task->req.offset);
|
||
|
||
co_get_from_shres(s->mem, task->req.bytes);
|
||
|
||
offset = task_end(task);
|
||
bytes = end - offset;
|
||
|
||
if (!aio && bytes) {
|
||
aio = aio_task_pool_new(call_state->max_workers);
|
||
}
|
||
|
||
ret = block_copy_task_run(aio, task);
|
||
if (ret < 0) {
|
||
goto out;
|
||
}
|
||
}
|
||
|
||
out:
|
||
if (aio) {
|
||
aio_task_pool_wait_all(aio);
|
||
|
||
/*
|
||
* We are not really interested in -ECANCELED returned from
|
||
* block_copy_task_run. If it fails, it means some task already failed
|
||
* for real reason, let's return first failure.
|
||
* Still, assert that we don't rewrite failure by success.
|
||
*
|
||
* Note: ret may be positive here because of block-status result.
|
||
*/
|
||
assert(ret >= 0 || aio_task_pool_status(aio) < 0);
|
||
ret = aio_task_pool_status(aio);
|
||
|
||
aio_task_pool_free(aio);
|
||
}
|
||
|
||
return ret < 0 ? ret : found_dirty;
|
||
}
|
||
|
||
void block_copy_kick(BlockCopyCallState *call_state)
|
||
{
|
||
qemu_co_sleep_wake(&call_state->sleep);
|
||
}
|
||
|
||
/*
|
||
* block_copy_common
|
||
*
|
||
* Copy requested region, accordingly to dirty bitmap.
|
||
* Collaborate with parallel block_copy requests: if they succeed it will help
|
||
* us. If they fail, we will retry not-copied regions. So, if we return error,
|
||
* it means that some I/O operation failed in context of _this_ block_copy call,
|
||
* not some parallel operation.
|
||
*/
|
||
static int coroutine_fn block_copy_common(BlockCopyCallState *call_state)
|
||
{
|
||
int ret;
|
||
BlockCopyState *s = call_state->s;
|
||
|
||
qemu_co_mutex_lock(&s->lock);
|
||
QLIST_INSERT_HEAD(&s->calls, call_state, list);
|
||
qemu_co_mutex_unlock(&s->lock);
|
||
|
||
do {
|
||
ret = block_copy_dirty_clusters(call_state);
|
||
|
||
if (ret == 0 && !qatomic_read(&call_state->cancelled)) {
|
||
WITH_QEMU_LOCK_GUARD(&s->lock) {
|
||
/*
|
||
* Check that there is no task we still need to
|
||
* wait to complete
|
||
*/
|
||
ret = reqlist_wait_one(&s->reqs, call_state->offset,
|
||
call_state->bytes, &s->lock);
|
||
if (ret == 0) {
|
||
/*
|
||
* No pending tasks, but check again the bitmap in this
|
||
* same critical section, since a task might have failed
|
||
* between this and the critical section in
|
||
* block_copy_dirty_clusters().
|
||
*
|
||
* reqlist_wait_one return value 0 also means that it
|
||
* didn't release the lock. So, we are still in the same
|
||
* critical section, not interrupted by any concurrent
|
||
* access to state.
|
||
*/
|
||
ret = bdrv_dirty_bitmap_next_dirty(s->copy_bitmap,
|
||
call_state->offset,
|
||
call_state->bytes) >= 0;
|
||
}
|
||
}
|
||
}
|
||
|
||
/*
|
||
* We retry in two cases:
|
||
* 1. Some progress done
|
||
* Something was copied, which means that there were yield points
|
||
* and some new dirty bits may have appeared (due to failed parallel
|
||
* block-copy requests).
|
||
* 2. We have waited for some intersecting block-copy request
|
||
* It may have failed and produced new dirty bits.
|
||
*/
|
||
} while (ret > 0 && !qatomic_read(&call_state->cancelled));
|
||
|
||
qatomic_store_release(&call_state->finished, true);
|
||
|
||
if (call_state->cb) {
|
||
call_state->cb(call_state->cb_opaque);
|
||
}
|
||
|
||
qemu_co_mutex_lock(&s->lock);
|
||
QLIST_REMOVE(call_state, list);
|
||
qemu_co_mutex_unlock(&s->lock);
|
||
|
||
return ret;
|
||
}
|
||
|
||
static void coroutine_fn block_copy_async_co_entry(void *opaque)
|
||
{
|
||
block_copy_common(opaque);
|
||
}
|
||
|
||
int coroutine_fn block_copy(BlockCopyState *s, int64_t start, int64_t bytes,
|
||
bool ignore_ratelimit, uint64_t timeout_ns,
|
||
BlockCopyAsyncCallbackFunc cb,
|
||
void *cb_opaque)
|
||
{
|
||
int ret;
|
||
BlockCopyCallState *call_state = g_new(BlockCopyCallState, 1);
|
||
|
||
*call_state = (BlockCopyCallState) {
|
||
.s = s,
|
||
.offset = start,
|
||
.bytes = bytes,
|
||
.ignore_ratelimit = ignore_ratelimit,
|
||
.max_workers = BLOCK_COPY_MAX_WORKERS,
|
||
.cb = cb,
|
||
.cb_opaque = cb_opaque,
|
||
};
|
||
|
||
ret = qemu_co_timeout(block_copy_async_co_entry, call_state, timeout_ns,
|
||
g_free);
|
||
if (ret < 0) {
|
||
assert(ret == -ETIMEDOUT);
|
||
block_copy_call_cancel(call_state);
|
||
/* call_state will be freed by running coroutine. */
|
||
return ret;
|
||
}
|
||
|
||
ret = call_state->ret;
|
||
g_free(call_state);
|
||
|
||
return ret;
|
||
}
|
||
|
||
BlockCopyCallState *block_copy_async(BlockCopyState *s,
|
||
int64_t offset, int64_t bytes,
|
||
int max_workers, int64_t max_chunk,
|
||
BlockCopyAsyncCallbackFunc cb,
|
||
void *cb_opaque)
|
||
{
|
||
BlockCopyCallState *call_state = g_new(BlockCopyCallState, 1);
|
||
|
||
*call_state = (BlockCopyCallState) {
|
||
.s = s,
|
||
.offset = offset,
|
||
.bytes = bytes,
|
||
.max_workers = max_workers,
|
||
.max_chunk = max_chunk,
|
||
.cb = cb,
|
||
.cb_opaque = cb_opaque,
|
||
|
||
.co = qemu_coroutine_create(block_copy_async_co_entry, call_state),
|
||
};
|
||
|
||
qemu_coroutine_enter(call_state->co);
|
||
|
||
return call_state;
|
||
}
|
||
|
||
void block_copy_call_free(BlockCopyCallState *call_state)
|
||
{
|
||
if (!call_state) {
|
||
return;
|
||
}
|
||
|
||
assert(qatomic_read(&call_state->finished));
|
||
g_free(call_state);
|
||
}
|
||
|
||
bool block_copy_call_finished(BlockCopyCallState *call_state)
|
||
{
|
||
return qatomic_read(&call_state->finished);
|
||
}
|
||
|
||
bool block_copy_call_succeeded(BlockCopyCallState *call_state)
|
||
{
|
||
return qatomic_load_acquire(&call_state->finished) &&
|
||
!qatomic_read(&call_state->cancelled) &&
|
||
call_state->ret == 0;
|
||
}
|
||
|
||
bool block_copy_call_failed(BlockCopyCallState *call_state)
|
||
{
|
||
return qatomic_load_acquire(&call_state->finished) &&
|
||
!qatomic_read(&call_state->cancelled) &&
|
||
call_state->ret < 0;
|
||
}
|
||
|
||
bool block_copy_call_cancelled(BlockCopyCallState *call_state)
|
||
{
|
||
return qatomic_read(&call_state->cancelled);
|
||
}
|
||
|
||
int block_copy_call_status(BlockCopyCallState *call_state, bool *error_is_read)
|
||
{
|
||
assert(qatomic_load_acquire(&call_state->finished));
|
||
if (error_is_read) {
|
||
*error_is_read = call_state->error_is_read;
|
||
}
|
||
return call_state->ret;
|
||
}
|
||
|
||
/*
|
||
* Note that cancelling and finishing are racy.
|
||
* User can cancel a block-copy that is already finished.
|
||
*/
|
||
void block_copy_call_cancel(BlockCopyCallState *call_state)
|
||
{
|
||
qatomic_set(&call_state->cancelled, true);
|
||
block_copy_kick(call_state);
|
||
}
|
||
|
||
BdrvDirtyBitmap *block_copy_dirty_bitmap(BlockCopyState *s)
|
||
{
|
||
return s->copy_bitmap;
|
||
}
|
||
|
||
int64_t block_copy_cluster_size(BlockCopyState *s)
|
||
{
|
||
return s->cluster_size;
|
||
}
|
||
|
||
void block_copy_set_skip_unallocated(BlockCopyState *s, bool skip)
|
||
{
|
||
qatomic_set(&s->skip_unallocated, skip);
|
||
}
|
||
|
||
void block_copy_set_speed(BlockCopyState *s, uint64_t speed)
|
||
{
|
||
ratelimit_set_speed(&s->rate_limit, speed, BLOCK_COPY_SLICE_TIME);
|
||
|
||
/*
|
||
* Note: it's good to kick all call states from here, but it should be done
|
||
* only from a coroutine, to not crash if s->calls list changed while
|
||
* entering one call. So for now, the only user of this function kicks its
|
||
* only one call_state by hand.
|
||
*/
|
||
}
|