Exemple #1
0
static void commit_clean(Job *job)
{
    CommitBlockJob *s = container_of(job, CommitBlockJob, common.job);

    /* restore base open flags here if appropriate (e.g., change the base back
     * to r/o). These reopens do not need to be atomic, since we won't abort
     * even on failure here */
    if (s->base_read_only) {
        bdrv_reopen_set_read_only(s->base_bs, true, NULL);
    }

    g_free(s->backing_file_str);
    blk_unref(s->top);
}
Exemple #2
0
static void stream_clean(Job *job)
{
    StreamBlockJob *s = container_of(job, StreamBlockJob, common.job);
    BlockJob *bjob = &s->common;
    BlockDriverState *bs = blk_bs(bjob->blk);

    /* Reopen the image back in read-only mode if necessary */
    if (s->bs_read_only) {
        /* Give up write permissions before making it read-only */
        blk_set_perm(bjob->blk, 0, BLK_PERM_ALL, &error_abort);
        bdrv_reopen_set_read_only(bs, true, NULL);
    }

    g_free(s->backing_file_str);
}
Exemple #3
0
void stream_start(const char *job_id, BlockDriverState *bs,
                  BlockDriverState *base, const char *backing_file_str,
                  int creation_flags, int64_t speed,
                  BlockdevOnError on_error, Error **errp)
{
    StreamBlockJob *s;
    BlockDriverState *iter;
    bool bs_read_only;

    if (bdrv_freeze_backing_chain(bs, base, errp) < 0) {
        return;
    }

    /* Make sure that the image is opened in read-write mode */
    bs_read_only = bdrv_is_read_only(bs);
    if (bs_read_only) {
        if (bdrv_reopen_set_read_only(bs, false, errp) != 0) {
            bs_read_only = false;
            goto fail;
        }
    }

    /* Prevent concurrent jobs trying to modify the graph structure here, we
     * already have our own plans. Also don't allow resize as the image size is
     * queried only at the job start and then cached. */
    s = block_job_create(job_id, &stream_job_driver, NULL, bs,
                         BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE_UNCHANGED |
                         BLK_PERM_GRAPH_MOD,
                         BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE_UNCHANGED |
                         BLK_PERM_WRITE,
                         speed, creation_flags, NULL, NULL, errp);
    if (!s) {
        goto fail;
    }

    /* Block all intermediate nodes between bs and base, because they will
     * disappear from the chain after this operation. The streaming job reads
     * every block only once, assuming that it doesn't change, so block writes
     * and resizes. */
    for (iter = backing_bs(bs); iter && iter != base; iter = backing_bs(iter)) {
        block_job_add_bdrv(&s->common, "intermediate node", iter, 0,
                           BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE_UNCHANGED,
                           &error_abort);
    }

    s->base = base;
    s->backing_file_str = g_strdup(backing_file_str);
    s->bs_read_only = bs_read_only;
    s->chain_frozen = true;

    s->on_error = on_error;
    trace_stream_start(bs, base, s);
    job_start(&s->common.job);
    return;

fail:
    if (bs_read_only) {
        bdrv_reopen_set_read_only(bs, true, NULL);
    }
    bdrv_unfreeze_backing_chain(bs, base);
}
Exemple #4
0
/* commit COW file into the raw image */
int bdrv_commit(BlockDriverState *bs)
{
    BlockBackend *src, *backing;
    BlockDriverState *backing_file_bs = NULL;
    BlockDriverState *commit_top_bs = NULL;
    BlockDriver *drv = bs->drv;
    int64_t offset, length, backing_length;
    int ro;
    int64_t n;
    int ret = 0;
    uint8_t *buf = NULL;
    Error *local_err = NULL;

    if (!drv)
        return -ENOMEDIUM;

    if (!bs->backing) {
        return -ENOTSUP;
    }

    if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_COMMIT_SOURCE, NULL) ||
        bdrv_op_is_blocked(bs->backing->bs, BLOCK_OP_TYPE_COMMIT_TARGET, NULL)) {
        return -EBUSY;
    }

    ro = bs->backing->bs->read_only;

    if (ro) {
        if (bdrv_reopen_set_read_only(bs->backing->bs, false, NULL)) {
            return -EACCES;
        }
    }

    src = blk_new(BLK_PERM_CONSISTENT_READ, BLK_PERM_ALL);
    backing = blk_new(BLK_PERM_WRITE | BLK_PERM_RESIZE, BLK_PERM_ALL);

    ret = blk_insert_bs(src, bs, &local_err);
    if (ret < 0) {
        error_report_err(local_err);
        goto ro_cleanup;
    }

    /* Insert commit_top block node above backing, so we can write to it */
    backing_file_bs = backing_bs(bs);

    commit_top_bs = bdrv_new_open_driver(&bdrv_commit_top, NULL, BDRV_O_RDWR,
                                         &local_err);
    if (commit_top_bs == NULL) {
        error_report_err(local_err);
        goto ro_cleanup;
    }
    bdrv_set_aio_context(commit_top_bs, bdrv_get_aio_context(backing_file_bs));

    bdrv_set_backing_hd(commit_top_bs, backing_file_bs, &error_abort);
    bdrv_set_backing_hd(bs, commit_top_bs, &error_abort);

    ret = blk_insert_bs(backing, backing_file_bs, &local_err);
    if (ret < 0) {
        error_report_err(local_err);
        goto ro_cleanup;
    }

    length = blk_getlength(src);
    if (length < 0) {
        ret = length;
        goto ro_cleanup;
    }

    backing_length = blk_getlength(backing);
    if (backing_length < 0) {
        ret = backing_length;
        goto ro_cleanup;
    }

    /* If our top snapshot is larger than the backing file image,
     * grow the backing file image if possible.  If not possible,
     * we must return an error */
    if (length > backing_length) {
        ret = blk_truncate(backing, length, PREALLOC_MODE_OFF, &local_err);
        if (ret < 0) {
            error_report_err(local_err);
            goto ro_cleanup;
        }
    }

    /* blk_try_blockalign() for src will choose an alignment that works for
     * backing as well, so no need to compare the alignment manually. */
    buf = blk_try_blockalign(src, COMMIT_BUF_SIZE);
    if (buf == NULL) {
        ret = -ENOMEM;
        goto ro_cleanup;
    }

    for (offset = 0; offset < length; offset += n) {
        ret = bdrv_is_allocated(bs, offset, COMMIT_BUF_SIZE, &n);
        if (ret < 0) {
            goto ro_cleanup;
        }
        if (ret) {
            ret = blk_pread(src, offset, buf, n);
            if (ret < 0) {
                goto ro_cleanup;
            }

            ret = blk_pwrite(backing, offset, buf, n, 0);
            if (ret < 0) {
                goto ro_cleanup;
            }
        }
    }

    if (drv->bdrv_make_empty) {
        ret = drv->bdrv_make_empty(bs);
        if (ret < 0) {
            goto ro_cleanup;
        }
        blk_flush(src);
    }

    /*
     * Make sure all data we wrote to the backing device is actually
     * stable on disk.
     */
    blk_flush(backing);

    ret = 0;
ro_cleanup:
    qemu_vfree(buf);

    blk_unref(backing);
    if (backing_file_bs) {
        bdrv_set_backing_hd(bs, backing_file_bs, &error_abort);
    }
    bdrv_unref(commit_top_bs);
    blk_unref(src);

    if (ro) {
        /* ignoring error return here */
        bdrv_reopen_set_read_only(bs->backing->bs, true, NULL);
    }

    return ret;
}
Exemple #5
0
void commit_start(const char *job_id, BlockDriverState *bs,
                  BlockDriverState *base, BlockDriverState *top,
                  int creation_flags, int64_t speed,
                  BlockdevOnError on_error, const char *backing_file_str,
                  const char *filter_node_name, Error **errp)
{
    CommitBlockJob *s;
    BlockDriverState *iter;
    BlockDriverState *commit_top_bs = NULL;
    Error *local_err = NULL;
    int ret;

    assert(top != bs);
    if (top == base) {
        error_setg(errp, "Invalid files for merge: top and base are the same");
        return;
    }

    s = block_job_create(job_id, &commit_job_driver, NULL, bs, 0, BLK_PERM_ALL,
                         speed, creation_flags, NULL, NULL, errp);
    if (!s) {
        return;
    }

    /* convert base to r/w, if necessary */
    s->base_read_only = bdrv_is_read_only(base);
    if (s->base_read_only) {
        if (bdrv_reopen_set_read_only(base, false, errp) != 0) {
            goto fail;
        }
    }

    /* Insert commit_top block node above top, so we can block consistent read
     * on the backing chain below it */
    commit_top_bs = bdrv_new_open_driver(&bdrv_commit_top, filter_node_name, 0,
                                         errp);
    if (commit_top_bs == NULL) {
        goto fail;
    }
    if (!filter_node_name) {
        commit_top_bs->implicit = true;
    }
    commit_top_bs->total_sectors = top->total_sectors;
    bdrv_set_aio_context(commit_top_bs, bdrv_get_aio_context(top));

    bdrv_set_backing_hd(commit_top_bs, top, &local_err);
    if (local_err) {
        bdrv_unref(commit_top_bs);
        commit_top_bs = NULL;
        error_propagate(errp, local_err);
        goto fail;
    }
    bdrv_replace_node(top, commit_top_bs, &local_err);
    if (local_err) {
        bdrv_unref(commit_top_bs);
        commit_top_bs = NULL;
        error_propagate(errp, local_err);
        goto fail;
    }

    s->commit_top_bs = commit_top_bs;
    bdrv_unref(commit_top_bs);

    /* Block all nodes between top and base, because they will
     * disappear from the chain after this operation. */
    assert(bdrv_chain_contains(top, base));
    for (iter = top; iter != base; iter = backing_bs(iter)) {
        /* XXX BLK_PERM_WRITE needs to be allowed so we don't block ourselves
         * at s->base (if writes are blocked for a node, they are also blocked
         * for its backing file). The other options would be a second filter
         * driver above s->base. */
        ret = block_job_add_bdrv(&s->common, "intermediate node", iter, 0,
                                 BLK_PERM_WRITE_UNCHANGED | BLK_PERM_WRITE,
                                 errp);
        if (ret < 0) {
            goto fail;
        }
    }

    if (bdrv_freeze_backing_chain(commit_top_bs, base, errp) < 0) {
        goto fail;
    }
    s->chain_frozen = true;

    ret = block_job_add_bdrv(&s->common, "base", base, 0, BLK_PERM_ALL, errp);
    if (ret < 0) {
        goto fail;
    }

    s->base = blk_new(BLK_PERM_CONSISTENT_READ
                      | BLK_PERM_WRITE
                      | BLK_PERM_RESIZE,
                      BLK_PERM_CONSISTENT_READ
                      | BLK_PERM_GRAPH_MOD
                      | BLK_PERM_WRITE_UNCHANGED);
    ret = blk_insert_bs(s->base, base, errp);
    if (ret < 0) {
        goto fail;
    }
    s->base_bs = base;

    /* Required permissions are already taken with block_job_add_bdrv() */
    s->top = blk_new(0, BLK_PERM_ALL);
    ret = blk_insert_bs(s->top, top, errp);
    if (ret < 0) {
        goto fail;
    }

    s->backing_file_str = g_strdup(backing_file_str);
    s->on_error = on_error;

    trace_commit_start(bs, base, top, s);
    job_start(&s->common.job);
    return;

fail:
    if (s->chain_frozen) {
        bdrv_unfreeze_backing_chain(commit_top_bs, base);
    }
    if (s->base) {
        blk_unref(s->base);
    }
    if (s->top) {
        blk_unref(s->top);
    }
    job_early_fail(&s->common.job);
    /* commit_top_bs has to be replaced after deleting the block job,
     * otherwise this would fail because of lack of permissions. */
    if (commit_top_bs) {
        bdrv_replace_node(commit_top_bs, top, &error_abort);
    }
}