]> Git Repo - qemu.git/blobdiff - block/backup.c
Merge remote-tracking branch 'remotes/kevin/tags/for-upstream' into staging
[qemu.git] / block / backup.c
index d3f648ddd72a2bd33d4c6ab967eb8b947f39ef7d..feeb9f8bf2643b17f3c8f297bf090d8f031e16c4 100644 (file)
  *
  */
 
-#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 {
@@ -36,8 +36,8 @@ typedef struct CowRequest {
 
 typedef struct BackupBlockJob {
     BlockJob common;
-    BlockDriverState *target;
-    /* bitmap for sync=dirty-bitmap */
+    BlockBackend *target;
+    /* bitmap for sync=incremental */
     BdrvDirtyBitmap *sync_bitmap;
     MirrorSyncMode sync_mode;
     RateLimit limit;
@@ -45,10 +45,18 @@ typedef struct BackupBlockJob {
     BlockdevOnError on_target_error;
     CoRwlock flush_rwlock;
     uint64_t sectors_read;
-    HBitmap *bitmap;
+    unsigned long *done_bitmap;
+    int64_t cluster_size;
+    NotifierWithReturn before_write;
     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,
@@ -86,23 +94,25 @@ static void cow_request_end(CowRequest *req)
     qemu_co_queue_restart_all(&req->wait_queue);
 }
 
-static int coroutine_fn backup_do_cow(BlockDriverState *bs,
+static int coroutine_fn backup_do_cow(BackupBlockJob *job,
                                       int64_t sector_num, int nb_sectors,
-                                      bool *error_is_read)
+                                      bool *error_is_read,
+                                      bool is_write_notifier)
 {
-    BackupBlockJob *job = (BackupBlockJob *)bs->job;
+    BlockBackend *blk = job->common.blk;
     CowRequest cow_request;
     struct iovec iov;
     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);
 
@@ -110,26 +120,27 @@ 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 = blk_blockalign(blk, 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);
+        ret = blk_co_preadv(blk, start * job->cluster_size,
+                            bounce_qiov.size, &bounce_qiov,
+                            is_write_notifier ? BDRV_REQ_NO_SERIALISING : 0);
         if (ret < 0) {
             trace_backup_do_cow_read_fail(job, start, ret);
             if (error_is_read) {
@@ -139,13 +150,11 @@ 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,
-                                       n, BDRV_REQ_MAY_UNMAP);
+            ret = blk_co_pwrite_zeroes(job->target, start * job->cluster_size,
+                                       bounce_qiov.size, BDRV_REQ_MAY_UNMAP);
         } else {
-            ret = bdrv_co_writev(job->target,
-                                 start * BACKUP_SECTORS_PER_CLUSTER, n,
-                                 &bounce_qiov);
+            ret = blk_co_pwritev(job->target, start * job->cluster_size,
+                                 bounce_qiov.size, &bounce_qiov, 0);
         }
         if (ret < 0) {
             trace_backup_do_cow_write_fail(job, start, ret);
@@ -155,7 +164,7 @@ 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.
@@ -182,14 +191,16 @@ static int coroutine_fn backup_before_write_notify(
         NotifierWithReturn *notifier,
         void *opaque)
 {
+    BackupBlockJob *job = container_of(notifier, BackupBlockJob, before_write);
     BdrvTrackedRequest *req = opaque;
     int64_t sector_num = req->offset >> BDRV_SECTOR_BITS;
     int nb_sectors = req->bytes >> BDRV_SECTOR_BITS;
 
+    assert(req->bs == blk_bs(job->common.blk));
     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(job, sector_num, nb_sectors, NULL, true);
 }
 
 static void backup_set_speed(BlockJob *job, int64_t speed, Error **errp)
@@ -197,35 +208,61 @@ static void backup_set_speed(BlockJob *job, int64_t speed, Error **errp)
     BackupBlockJob *s = container_of(job, BackupBlockJob, common);
 
     if (speed < 0) {
-        error_set(errp, QERR_INVALID_PARAMETER, "speed");
+        error_setg(errp, QERR_INVALID_PARAMETER, "speed");
         return;
     }
     ratelimit_set_speed(&s->limit, speed / BDRV_SECTOR_SIZE, SLICE_TIME);
 }
 
-static void backup_iostatus_reset(BlockJob *job)
+static void backup_cleanup_sync_bitmap(BackupBlockJob *job, int ret)
+{
+    BdrvDirtyBitmap *bm;
+    BlockDriverState *bs = blk_bs(job->common.blk);
+
+    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);
+    }
+}
 
-    bdrv_iostatus_reset(s->target);
+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 = {
     .instance_size  = sizeof(BackupBlockJob),
     .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,
                                             bool read, int error)
 {
     if (read) {
-        return block_job_error_action(&job->common, job->common.bs,
-                                      job->on_source_error, true, error);
+        return block_job_error_action(&job->common, job->on_source_error,
+                                      true, error);
     } else {
-        return block_job_error_action(&job->common, job->target,
-                                      job->on_target_error, false, error);
+        return block_job_error_action(&job->common, job->on_target_error,
+                                      false, error);
     }
 }
 
@@ -238,7 +275,7 @@ static void backup_complete(BlockJob *job, void *opaque)
     BackupBlockJob *s = container_of(job, BackupBlockJob, common);
     BackupCompleteData *data = opaque;
 
-    bdrv_unref(s->target);
+    blk_unref(s->target);
 
     block_job_completed(job, data->ret);
     g_free(data);
@@ -279,21 +316,21 @@ static int coroutine_fn backup_run_incremental(BackupBlockJob *job)
     int64_t cluster;
     int64_t end;
     int64_t last_cluster = -1;
-    BlockDriverState *bs = job->common.bs;
+    int64_t sectors_per_cluster = cluster_size_sectors(job);
     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++) {
@@ -301,8 +338,9 @@ 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(job, 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) {
@@ -313,17 +351,17 @@ 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;
@@ -333,28 +371,22 @@ static void coroutine_fn backup_run(void *opaque)
 {
     BackupBlockJob *job = opaque;
     BackupCompleteData *data;
-    BlockDriverState *bs = job->common.bs;
-    BlockDriverState *target = job->target;
-    BlockdevOnError on_target_error = job->on_target_error;
-    NotifierWithReturn before_write = {
-        .notify = backup_before_write_notify,
-    };
+    BlockDriverState *bs = blk_bs(job->common.blk);
+    BlockBackend *target = job->target;
     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);
-
-    bdrv_add_before_write_notifier(bs, &before_write);
+    job->before_write.notify = backup_before_write_notify;
+    bdrv_add_before_write_notifier(bs, &job->before_write);
 
     if (job->sync_mode == MIRROR_SYNC_MODE_NONE) {
         while (!block_job_is_cancelled(&job->common)) {
@@ -364,7 +396,7 @@ static void coroutine_fn backup_run(void *opaque)
             qemu_coroutine_yield();
             job->common.busy = true;
         }
-    } else if (job->sync_mode == MIRROR_SYNC_MODE_DIRTY_BITMAP) {
+    } else if (job->sync_mode == MIRROR_SYNC_MODE_INCREMENTAL) {
         ret = backup_run_incremental(job);
     } else {
         /* Both FULL and TOP SYNC_MODE's require copying.. */
@@ -381,7 +413,7 @@ 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.
@@ -390,8 +422,8 @@ 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) {
@@ -406,8 +438,8 @@ 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(job, 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 =
@@ -422,28 +454,14 @@ static void coroutine_fn backup_run(void *opaque)
         }
     }
 
-    notifier_with_return_remove(&before_write);
+    notifier_with_return_remove(&job->before_write);
 
     /* 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) {
-            /* 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);
-        }
-    }
-    hbitmap_free(job->bitmap);
-
-    bdrv_iostatus_disable(target);
-    bdrv_op_unblock_all(target, job->common.blocker);
+    bdrv_op_unblock_all(blk_bs(target), job->common.blocker);
 
     data = g_malloc(sizeof(*data));
     data->ret = ret;
@@ -456,9 +474,12 @@ 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;
+    BackupBlockJob *job = NULL;
+    int ret;
 
     assert(bs);
     assert(target);
@@ -469,13 +490,6 @@ void backup_start(BlockDriverState *bs, BlockDriverState *target,
         return;
     }
 
-    if ((on_source_error == BLOCKDEV_ON_ERROR_STOP ||
-         on_source_error == BLOCKDEV_ON_ERROR_ENOSPC) &&
-        !bdrv_iostatus_is_enabled(bs)) {
-        error_set(errp, QERR_INVALID_PARAMETER, "on-source-error");
-        return;
-    }
-
     if (!bdrv_is_inserted(bs)) {
         error_setg(errp, "Device is not inserted: %s",
                    bdrv_get_device_name(bs));
@@ -496,10 +510,10 @@ void backup_start(BlockDriverState *bs, BlockDriverState *target,
         return;
     }
 
-    if (sync_mode == MIRROR_SYNC_MODE_DIRTY_BITMAP) {
+    if (sync_mode == MIRROR_SYNC_MODE_INCREMENTAL) {
         if (!sync_bitmap) {
             error_setg(errp, "must provide a valid bitmap name for "
-                             "\"dirty-bitmap\" sync mode");
+                             "\"incremental\" sync mode");
             return;
         }
 
@@ -522,22 +536,42 @@ void backup_start(BlockDriverState *bs, BlockDriverState *target,
         goto error;
     }
 
-    BackupBlockJob *job = block_job_create(&backup_job_driver, bs, speed,
-                                           cb, opaque, errp);
+    job = block_job_create(&backup_job_driver, bs, speed, cb, opaque, errp);
     if (!job) {
         goto error;
     }
 
-    bdrv_op_block_all(target, job->common.blocker);
+    job->target = blk_new();
+    blk_insert_bs(job->target, target);
 
     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_DIRTY_BITMAP ?
+    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(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;
 
@@ -545,4 +579,8 @@ void backup_start(BlockDriverState *bs, BlockDriverState *target,
     if (sync_bitmap) {
         bdrv_reclaim_dirty_bitmap(bs, sync_bitmap, NULL);
     }
+    if (job) {
+        blk_unref(job->target);
+        block_job_unref(&job->common);
+    }
 }
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