diff options
Diffstat (limited to 'qemu/block/backup.c')
| -rw-r--r-- | qemu/block/backup.c | 182 |
1 files changed, 123 insertions, 59 deletions
diff --git a/qemu/block/backup.c b/qemu/block/backup.c index 965654d52..491fd1406 100644 --- a/qemu/block/backup.c +++ b/qemu/block/backup.c @@ -11,21 +11,20 @@ * */ -#include <stdio.h> -#include <errno.h> -#include <unistd.h> +#include "qemu/osdep.h" #include "trace.h" #include "block/block.h" #include "block/block_int.h" #include "block/blockjob.h" +#include "qapi/error.h" #include "qapi/qmp/qerror.h" #include "qemu/ratelimit.h" +#include "qemu/cutils.h" +#include "sysemu/block-backend.h" +#include "qemu/bitmap.h" -#define BACKUP_CLUSTER_BITS 16 -#define BACKUP_CLUSTER_SIZE (1 << BACKUP_CLUSTER_BITS) -#define BACKUP_SECTORS_PER_CLUSTER (BACKUP_CLUSTER_SIZE / BDRV_SECTOR_SIZE) - +#define BACKUP_CLUSTER_SIZE_DEFAULT (1 << 16) #define SLICE_TIME 100000000ULL /* ns */ typedef struct CowRequest { @@ -46,10 +45,17 @@ typedef struct BackupBlockJob { BlockdevOnError on_target_error; CoRwlock flush_rwlock; uint64_t sectors_read; - HBitmap *bitmap; + unsigned long *done_bitmap; + int64_t cluster_size; QLIST_HEAD(, CowRequest) inflight_reqs; } BackupBlockJob; +/* Size of a cluster in sectors, instead of bytes. */ +static inline int64_t cluster_size_sectors(BackupBlockJob *job) +{ + return job->cluster_size / BDRV_SECTOR_SIZE; +} + /* See if in-flight requests overlap and wait for them to complete */ static void coroutine_fn wait_for_overlapping_requests(BackupBlockJob *job, int64_t start, @@ -89,7 +95,8 @@ static void cow_request_end(CowRequest *req) static int coroutine_fn backup_do_cow(BlockDriverState *bs, int64_t sector_num, int nb_sectors, - bool *error_is_read) + bool *error_is_read, + bool is_write_notifier) { BackupBlockJob *job = (BackupBlockJob *)bs->job; CowRequest cow_request; @@ -97,13 +104,14 @@ static int coroutine_fn backup_do_cow(BlockDriverState *bs, QEMUIOVector bounce_qiov; void *bounce_buffer = NULL; int ret = 0; + int64_t sectors_per_cluster = cluster_size_sectors(job); int64_t start, end; int n; qemu_co_rwlock_rdlock(&job->flush_rwlock); - start = sector_num / BACKUP_SECTORS_PER_CLUSTER; - end = DIV_ROUND_UP(sector_num + nb_sectors, BACKUP_SECTORS_PER_CLUSTER); + start = sector_num / sectors_per_cluster; + end = DIV_ROUND_UP(sector_num + nb_sectors, sectors_per_cluster); trace_backup_do_cow_enter(job, start, sector_num, nb_sectors); @@ -111,26 +119,32 @@ static int coroutine_fn backup_do_cow(BlockDriverState *bs, cow_request_begin(&cow_request, job, start, end); for (; start < end; start++) { - if (hbitmap_get(job->bitmap, start)) { + if (test_bit(start, job->done_bitmap)) { trace_backup_do_cow_skip(job, start); continue; /* already copied */ } trace_backup_do_cow_process(job, start); - n = MIN(BACKUP_SECTORS_PER_CLUSTER, + n = MIN(sectors_per_cluster, job->common.len / BDRV_SECTOR_SIZE - - start * BACKUP_SECTORS_PER_CLUSTER); + start * sectors_per_cluster); if (!bounce_buffer) { - bounce_buffer = qemu_blockalign(bs, BACKUP_CLUSTER_SIZE); + bounce_buffer = qemu_blockalign(bs, job->cluster_size); } iov.iov_base = bounce_buffer; iov.iov_len = n * BDRV_SECTOR_SIZE; qemu_iovec_init_external(&bounce_qiov, &iov, 1); - ret = bdrv_co_readv(bs, start * BACKUP_SECTORS_PER_CLUSTER, n, - &bounce_qiov); + if (is_write_notifier) { + ret = bdrv_co_readv_no_serialising(bs, + start * sectors_per_cluster, + n, &bounce_qiov); + } else { + ret = bdrv_co_readv(bs, start * sectors_per_cluster, n, + &bounce_qiov); + } if (ret < 0) { trace_backup_do_cow_read_fail(job, start, ret); if (error_is_read) { @@ -141,11 +155,11 @@ static int coroutine_fn backup_do_cow(BlockDriverState *bs, if (buffer_is_zero(iov.iov_base, iov.iov_len)) { ret = bdrv_co_write_zeroes(job->target, - start * BACKUP_SECTORS_PER_CLUSTER, + start * sectors_per_cluster, n, BDRV_REQ_MAY_UNMAP); } else { ret = bdrv_co_writev(job->target, - start * BACKUP_SECTORS_PER_CLUSTER, n, + start * sectors_per_cluster, n, &bounce_qiov); } if (ret < 0) { @@ -156,7 +170,7 @@ static int coroutine_fn backup_do_cow(BlockDriverState *bs, goto out; } - hbitmap_set(job->bitmap, start, 1); + set_bit(start, job->done_bitmap); /* Publish progress, guest I/O counts as progress too. Note that the * offset field is an opaque progress value, it is not a disk offset. @@ -190,7 +204,7 @@ static int coroutine_fn backup_before_write_notify( assert((req->offset & (BDRV_SECTOR_SIZE - 1)) == 0); assert((req->bytes & (BDRV_SECTOR_SIZE - 1)) == 0); - return backup_do_cow(req->bs, sector_num, nb_sectors, NULL); + return backup_do_cow(req->bs, sector_num, nb_sectors, NULL, true); } static void backup_set_speed(BlockJob *job, int64_t speed, Error **errp) @@ -208,7 +222,41 @@ static void backup_iostatus_reset(BlockJob *job) { BackupBlockJob *s = container_of(job, BackupBlockJob, common); - bdrv_iostatus_reset(s->target); + if (s->target->blk) { + blk_iostatus_reset(s->target->blk); + } +} + +static void backup_cleanup_sync_bitmap(BackupBlockJob *job, int ret) +{ + BdrvDirtyBitmap *bm; + BlockDriverState *bs = job->common.bs; + + if (ret < 0 || block_job_is_cancelled(&job->common)) { + /* Merge the successor back into the parent, delete nothing. */ + bm = bdrv_reclaim_dirty_bitmap(bs, job->sync_bitmap, NULL); + assert(bm); + } else { + /* Everything is fine, delete this bitmap and install the backup. */ + bm = bdrv_dirty_bitmap_abdicate(bs, job->sync_bitmap, NULL); + assert(bm); + } +} + +static void backup_commit(BlockJob *job) +{ + BackupBlockJob *s = container_of(job, BackupBlockJob, common); + if (s->sync_bitmap) { + backup_cleanup_sync_bitmap(s, 0); + } +} + +static void backup_abort(BlockJob *job) +{ + BackupBlockJob *s = container_of(job, BackupBlockJob, common); + if (s->sync_bitmap) { + backup_cleanup_sync_bitmap(s, -1); + } } static const BlockJobDriver backup_job_driver = { @@ -216,6 +264,8 @@ static const BlockJobDriver backup_job_driver = { .job_type = BLOCK_JOB_TYPE_BACKUP, .set_speed = backup_set_speed, .iostatus_reset = backup_iostatus_reset, + .commit = backup_commit, + .abort = backup_abort, }; static BlockErrorAction backup_error_action(BackupBlockJob *job, @@ -280,21 +330,22 @@ static int coroutine_fn backup_run_incremental(BackupBlockJob *job) int64_t cluster; int64_t end; int64_t last_cluster = -1; + int64_t sectors_per_cluster = cluster_size_sectors(job); BlockDriverState *bs = job->common.bs; HBitmapIter hbi; granularity = bdrv_dirty_bitmap_granularity(job->sync_bitmap); - clusters_per_iter = MAX((granularity / BACKUP_CLUSTER_SIZE), 1); + clusters_per_iter = MAX((granularity / job->cluster_size), 1); bdrv_dirty_iter_init(job->sync_bitmap, &hbi); /* Find the next dirty sector(s) */ while ((sector = hbitmap_iter_next(&hbi)) != -1) { - cluster = sector / BACKUP_SECTORS_PER_CLUSTER; + cluster = sector / sectors_per_cluster; /* Fake progress updates for any clusters we skipped */ if (cluster != last_cluster + 1) { job->common.offset += ((cluster - last_cluster - 1) * - BACKUP_CLUSTER_SIZE); + job->cluster_size); } for (end = cluster + clusters_per_iter; cluster < end; cluster++) { @@ -302,8 +353,9 @@ static int coroutine_fn backup_run_incremental(BackupBlockJob *job) if (yield_and_check(job)) { return ret; } - ret = backup_do_cow(bs, cluster * BACKUP_SECTORS_PER_CLUSTER, - BACKUP_SECTORS_PER_CLUSTER, &error_is_read); + ret = backup_do_cow(bs, cluster * sectors_per_cluster, + sectors_per_cluster, &error_is_read, + false); if ((ret < 0) && backup_error_action(job, error_is_read, -ret) == BLOCK_ERROR_ACTION_REPORT) { @@ -314,17 +366,17 @@ static int coroutine_fn backup_run_incremental(BackupBlockJob *job) /* If the bitmap granularity is smaller than the backup granularity, * we need to advance the iterator pointer to the next cluster. */ - if (granularity < BACKUP_CLUSTER_SIZE) { - bdrv_set_dirty_iter(&hbi, cluster * BACKUP_SECTORS_PER_CLUSTER); + if (granularity < job->cluster_size) { + bdrv_set_dirty_iter(&hbi, cluster * sectors_per_cluster); } last_cluster = cluster - 1; } /* Play some final catchup with the progress meter */ - end = DIV_ROUND_UP(job->common.len, BACKUP_CLUSTER_SIZE); + end = DIV_ROUND_UP(job->common.len, job->cluster_size); if (last_cluster + 1 < end) { - job->common.offset += ((end - last_cluster - 1) * BACKUP_CLUSTER_SIZE); + job->common.offset += ((end - last_cluster - 1) * job->cluster_size); } return ret; @@ -341,19 +393,21 @@ static void coroutine_fn backup_run(void *opaque) .notify = backup_before_write_notify, }; int64_t start, end; + int64_t sectors_per_cluster = cluster_size_sectors(job); int ret = 0; QLIST_INIT(&job->inflight_reqs); qemu_co_rwlock_init(&job->flush_rwlock); start = 0; - end = DIV_ROUND_UP(job->common.len, BACKUP_CLUSTER_SIZE); + end = DIV_ROUND_UP(job->common.len, job->cluster_size); - job->bitmap = hbitmap_alloc(end, 0); + job->done_bitmap = bitmap_new(end); - bdrv_set_enable_write_cache(target, true); - bdrv_set_on_error(target, on_target_error, on_target_error); - bdrv_iostatus_enable(target); + if (target->blk) { + blk_set_on_error(target->blk, on_target_error, on_target_error); + blk_iostatus_enable(target->blk); + } bdrv_add_before_write_notifier(bs, &before_write); @@ -382,7 +436,7 @@ static void coroutine_fn backup_run(void *opaque) /* Check to see if these blocks are already in the * backing file. */ - for (i = 0; i < BACKUP_SECTORS_PER_CLUSTER;) { + for (i = 0; i < sectors_per_cluster;) { /* bdrv_is_allocated() only returns true/false based * on the first set of sectors it comes across that * are are all in the same state. @@ -391,8 +445,8 @@ static void coroutine_fn backup_run(void *opaque) * needed but at some point that is always the case. */ alloced = bdrv_is_allocated(bs, - start * BACKUP_SECTORS_PER_CLUSTER + i, - BACKUP_SECTORS_PER_CLUSTER - i, &n); + start * sectors_per_cluster + i, + sectors_per_cluster - i, &n); i += n; if (alloced == 1 || n == 0) { @@ -407,8 +461,8 @@ static void coroutine_fn backup_run(void *opaque) } } /* FULL sync mode we copy the whole drive. */ - ret = backup_do_cow(bs, start * BACKUP_SECTORS_PER_CLUSTER, - BACKUP_SECTORS_PER_CLUSTER, &error_is_read); + ret = backup_do_cow(bs, start * sectors_per_cluster, + sectors_per_cluster, &error_is_read, false); if (ret < 0) { /* Depending on error action, fail now or retry cluster */ BlockErrorAction action = @@ -428,22 +482,11 @@ static void coroutine_fn backup_run(void *opaque) /* wait until pending backup_do_cow() calls have completed */ qemu_co_rwlock_wrlock(&job->flush_rwlock); qemu_co_rwlock_unlock(&job->flush_rwlock); + g_free(job->done_bitmap); - if (job->sync_bitmap) { - BdrvDirtyBitmap *bm; - if (ret < 0 || block_job_is_cancelled(&job->common)) { - /* Merge the successor back into the parent, delete nothing. */ - bm = bdrv_reclaim_dirty_bitmap(bs, job->sync_bitmap, NULL); - assert(bm); - } else { - /* Everything is fine, delete this bitmap and install the backup. */ - bm = bdrv_dirty_bitmap_abdicate(bs, job->sync_bitmap, NULL); - assert(bm); - } + if (target->blk) { + blk_iostatus_disable(target->blk); } - hbitmap_free(job->bitmap); - - bdrv_iostatus_disable(target); bdrv_op_unblock_all(target, job->common.blocker); data = g_malloc(sizeof(*data)); @@ -457,9 +500,11 @@ void backup_start(BlockDriverState *bs, BlockDriverState *target, BlockdevOnError on_source_error, BlockdevOnError on_target_error, BlockCompletionFunc *cb, void *opaque, - Error **errp) + BlockJobTxn *txn, Error **errp) { int64_t len; + BlockDriverInfo bdi; + int ret; assert(bs); assert(target); @@ -472,7 +517,7 @@ void backup_start(BlockDriverState *bs, BlockDriverState *target, if ((on_source_error == BLOCKDEV_ON_ERROR_STOP || on_source_error == BLOCKDEV_ON_ERROR_ENOSPC) && - !bdrv_iostatus_is_enabled(bs)) { + (!bs->blk || !blk_iostatus_is_enabled(bs->blk))) { error_setg(errp, QERR_INVALID_PARAMETER, "on-source-error"); return; } @@ -529,16 +574,35 @@ void backup_start(BlockDriverState *bs, BlockDriverState *target, goto error; } - bdrv_op_block_all(target, job->common.blocker); - job->on_source_error = on_source_error; job->on_target_error = on_target_error; job->target = target; job->sync_mode = sync_mode; job->sync_bitmap = sync_mode == MIRROR_SYNC_MODE_INCREMENTAL ? sync_bitmap : NULL; + + /* If there is no backing file on the target, we cannot rely on COW if our + * backup cluster size is smaller than the target cluster size. Even for + * targets with a backing file, try to avoid COW if possible. */ + ret = bdrv_get_info(job->target, &bdi); + if (ret < 0 && !target->backing) { + error_setg_errno(errp, -ret, + "Couldn't determine the cluster size of the target image, " + "which has no backing file"); + error_append_hint(errp, + "Aborting, since this may create an unusable destination image\n"); + goto error; + } else if (ret < 0 && target->backing) { + /* Not fatal; just trudge on ahead. */ + job->cluster_size = BACKUP_CLUSTER_SIZE_DEFAULT; + } else { + job->cluster_size = MAX(BACKUP_CLUSTER_SIZE_DEFAULT, bdi.cluster_size); + } + + bdrv_op_block_all(target, job->common.blocker); job->common.len = len; job->common.co = qemu_coroutine_create(backup_run); + block_job_txn_add_job(txn, &job->common); qemu_coroutine_enter(job->common.co, job); return; |