diff options
Diffstat (limited to 'block/copy-before-write.c')
| -rw-r--r-- | block/copy-before-write.c | 110 |
1 files changed, 80 insertions, 30 deletions
diff --git a/block/copy-before-write.c b/block/copy-before-write.c index a8a06fdc09..c24b8dd117 100644 --- a/block/copy-before-write.c +++ b/block/copy-before-write.c @@ -24,6 +24,7 @@ */ #include "qemu/osdep.h" +#include "qapi/qmp/qjson.h" #include "sysemu/block-backend.h" #include "qemu/cutils.h" @@ -40,6 +41,8 @@ typedef struct BDRVCopyBeforeWriteState { BlockCopyState *bcs; BdrvChild *target; + OnCbwError on_cbw_error; + uint32_t cbw_timeout_ns; /* * @lock: protects access to @access_bitmap, @done_bitmap and @@ -64,6 +67,14 @@ typedef struct BDRVCopyBeforeWriteState { * node. These areas must not be rewritten by guest. */ BlockReqList frozen_read_reqs; + + /* + * @snapshot_error is normally zero. But on first copy-before-write failure + * when @on_cbw_error == ON_CBW_ERROR_BREAK_SNAPSHOT, @snapshot_error takes + * value of this error (<0). After that all in-flight and further + * snapshot-API requests will fail with that error. + */ + int snapshot_error; } BDRVCopyBeforeWriteState; static coroutine_fn int cbw_co_preadv( @@ -73,6 +84,13 @@ static coroutine_fn int cbw_co_preadv( return bdrv_co_preadv(bs->file, offset, bytes, qiov, flags); } +static void block_copy_cb(void *opaque) +{ + BlockDriverState *bs = opaque; + + bdrv_dec_in_flight(bs); +} + /* * Do copy-before-write operation. * @@ -94,16 +112,36 @@ static coroutine_fn int cbw_do_copy_before_write(BlockDriverState *bs, return 0; } + if (s->snapshot_error) { + return 0; + } + off = QEMU_ALIGN_DOWN(offset, cluster_size); end = QEMU_ALIGN_UP(offset + bytes, cluster_size); - ret = block_copy(s->bcs, off, end - off, true); - if (ret < 0) { + /* + * Increase in_flight, so that in case of timed-out block-copy, the + * remaining background block_copy() request (which can't be immediately + * cancelled by timeout) is presented in bs->in_flight. This way we are + * sure that on bs close() we'll previously wait for all timed-out but yet + * running block_copy calls. + */ + bdrv_inc_in_flight(bs); + ret = block_copy(s->bcs, off, end - off, true, s->cbw_timeout_ns, + block_copy_cb, bs); + if (ret < 0 && s->on_cbw_error == ON_CBW_ERROR_BREAK_GUEST_WRITE) { return ret; } WITH_QEMU_LOCK_GUARD(&s->lock) { - bdrv_set_dirty_bitmap(s->done_bitmap, off, end - off); + if (ret < 0) { + assert(s->on_cbw_error == ON_CBW_ERROR_BREAK_SNAPSHOT); + if (!s->snapshot_error) { + s->snapshot_error = ret; + } + } else { + bdrv_set_dirty_bitmap(s->done_bitmap, off, end - off); + } reqlist_wait_all(&s->frozen_read_reqs, off, end - off, &s->lock); } @@ -175,6 +213,11 @@ static BlockReq *cbw_snapshot_read_lock(BlockDriverState *bs, QEMU_LOCK_GUARD(&s->lock); + if (s->snapshot_error) { + g_free(req); + return NULL; + } + if (bdrv_dirty_bitmap_next_zero(s->access_bitmap, offset, bytes) != -1) { g_free(req); return NULL; @@ -328,46 +371,36 @@ static void cbw_child_perm(BlockDriverState *bs, BdrvChild *c, } } -static bool cbw_parse_bitmap_option(QDict *options, BdrvDirtyBitmap **bitmap, - Error **errp) +static BlockdevOptions *cbw_parse_options(QDict *options, Error **errp) { - QDict *bitmap_qdict = NULL; - BlockDirtyBitmap *bmp_param = NULL; + BlockdevOptions *opts = NULL; Visitor *v = NULL; - bool ret = false; - *bitmap = NULL; + qdict_put_str(options, "driver", "copy-before-write"); - qdict_extract_subqdict(options, &bitmap_qdict, "bitmap."); - if (!qdict_size(bitmap_qdict)) { - ret = true; - goto out; - } - - v = qobject_input_visitor_new_flat_confused(bitmap_qdict, errp); + v = qobject_input_visitor_new_flat_confused(options, errp); if (!v) { goto out; } - visit_type_BlockDirtyBitmap(v, NULL, &bmp_param, errp); - if (!bmp_param) { - goto out; - } - - *bitmap = block_dirty_bitmap_lookup(bmp_param->node, bmp_param->name, NULL, - errp); - if (!*bitmap) { + visit_type_BlockdevOptions(v, NULL, &opts, errp); + if (!opts) { goto out; } - ret = true; + /* + * Delete options which we are going to parse through BlockdevOptions + * object for original options. + */ + qdict_extract_subqdict(options, NULL, "bitmap"); + qdict_del(options, "on-cbw-error"); + qdict_del(options, "cbw-timeout"); out: - qapi_free_BlockDirtyBitmap(bmp_param); visit_free(v); - qobject_unref(bitmap_qdict); + qdict_del(options, "driver"); - return ret; + return opts; } static int cbw_open(BlockDriverState *bs, QDict *options, int flags, @@ -376,6 +409,15 @@ static int cbw_open(BlockDriverState *bs, QDict *options, int flags, BDRVCopyBeforeWriteState *s = bs->opaque; BdrvDirtyBitmap *bitmap = NULL; int64_t cluster_size; + g_autoptr(BlockdevOptions) full_opts = NULL; + BlockdevOptionsCbw *opts; + + full_opts = cbw_parse_options(options, errp); + if (!full_opts) { + return -EINVAL; + } + assert(full_opts->driver == BLOCKDEV_DRIVER_COPY_BEFORE_WRITE); + opts = &full_opts->u.copy_before_write; bs->file = bdrv_open_child(NULL, options, "file", bs, &child_of_bds, BDRV_CHILD_FILTERED | BDRV_CHILD_PRIMARY, @@ -390,9 +432,17 @@ static int cbw_open(BlockDriverState *bs, QDict *options, int flags, return -EINVAL; } - if (!cbw_parse_bitmap_option(options, &bitmap, errp)) { - return -EINVAL; + if (opts->has_bitmap) { + bitmap = block_dirty_bitmap_lookup(opts->bitmap->node, + opts->bitmap->name, NULL, errp); + if (!bitmap) { + return -EINVAL; + } } + s->on_cbw_error = opts->has_on_cbw_error ? opts->on_cbw_error : + ON_CBW_ERROR_BREAK_GUEST_WRITE; + s->cbw_timeout_ns = opts->has_cbw_timeout ? + opts->cbw_timeout * NANOSECONDS_PER_SECOND : 0; bs->total_sectors = bs->file->bs->total_sectors; bs->supported_write_flags = BDRV_REQ_WRITE_UNCHANGED | |