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[Qemu-devel] [PATCH v1 02/18] block/pcache: empty pcache driver filter


From: Pavel Butsykin
Subject: [Qemu-devel] [PATCH v1 02/18] block/pcache: empty pcache driver filter
Date: Tue, 15 Nov 2016 09:36:59 +0300

The basic version of pcache driver for easy preparation of a patch set.

Signed-off-by: Pavel Butsykin <address@hidden>
---
 block/Makefile.objs |   1 +
 block/pcache.c      | 144 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 145 insertions(+)
 create mode 100644 block/pcache.c

diff --git a/block/Makefile.objs b/block/Makefile.objs
index 7d4031d..c60f680 100644
--- a/block/Makefile.objs
+++ b/block/Makefile.objs
@@ -4,6 +4,7 @@ block-obj-y += qed.o qed-gencb.o qed-l2-cache.o qed-table.o 
qed-cluster.o
 block-obj-y += qed-check.o
 block-obj-y += vhdx.o vhdx-endian.o vhdx-log.o
 block-obj-y += quorum.o
+block-obj-y += pcache.o
 block-obj-y += parallels.o blkdebug.o blkverify.o blkreplay.o
 block-obj-y += block-backend.o snapshot.o qapi.o
 block-obj-$(CONFIG_WIN32) += raw-win32.o win32-aio.o
diff --git a/block/pcache.c b/block/pcache.c
new file mode 100644
index 0000000..59461df
--- /dev/null
+++ b/block/pcache.c
@@ -0,0 +1,144 @@
+/*
+ * Prefetch cache driver filter
+ *
+ * Copyright (C) 2015-2016 Parallels IP Holdings GmbH. All rights reserved.
+ *
+ * Author: Pavel Butsykin <address@hidden>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or
+ * later.  See the COPYING file in the top-level directory.
+ */
+
+#include "qemu/osdep.h"
+#include "block/block_int.h"
+#include "qapi/error.h"
+#include "qapi/qmp/qstring.h"
+
+
+static QemuOptsList runtime_opts = {
+    .name = "pcache",
+    .head = QTAILQ_HEAD_INITIALIZER(runtime_opts.head),
+    .desc = {
+        {
+            .name = "x-image",
+            .type = QEMU_OPT_STRING,
+            .help = "[internal use only, will be removed]",
+        },
+        { /* end of list */ }
+    },
+};
+
+typedef struct PCacheAIOCB {
+    Coroutine *co;
+    int ret;
+} PCacheAIOCB;
+
+static void pcache_aio_cb(void *opaque, int ret)
+{
+    PCacheAIOCB *acb = opaque;
+
+    acb->ret = ret;
+    qemu_coroutine_enter(acb->co);
+}
+
+static coroutine_fn int pcache_co_preadv(BlockDriverState *bs, uint64_t offset,
+                                         uint64_t bytes, QEMUIOVector *qiov,
+                                         int flags)
+{
+    PCacheAIOCB acb = {
+        .co = qemu_coroutine_self(),
+    };
+
+    bdrv_aio_preadv(bs->file, offset, qiov, bytes, pcache_aio_cb, &acb);
+
+    qemu_coroutine_yield();
+
+    return acb.ret;
+}
+
+static coroutine_fn int pcache_co_pwritev(BlockDriverState *bs, uint64_t 
offset,
+                                          uint64_t bytes, QEMUIOVector *qiov,
+                                          int flags)
+{
+    PCacheAIOCB acb = {
+        .co = qemu_coroutine_self(),
+    };
+
+    bdrv_aio_pwritev(bs->file, offset, qiov, bytes, pcache_aio_cb, &acb);
+
+    qemu_coroutine_yield();
+
+    return acb.ret;
+}
+
+static int pcache_file_open(BlockDriverState *bs, QDict *options, int flags,
+                            Error **errp)
+{
+    QemuOpts *opts;
+    Error *local_err = NULL;
+    int ret = 0;
+
+    opts = qemu_opts_create(&runtime_opts, NULL, 0, &error_abort);
+    qemu_opts_absorb_qdict(opts, options, &local_err);
+    if (local_err) {
+        error_propagate(errp, local_err);
+        ret = -EINVAL;
+        goto fail;
+    }
+
+    assert(bs->file == NULL);
+    bs->file = bdrv_open_child(qemu_opt_get(opts, "x-image"), options,
+                               "image", bs, &child_format, false, &local_err);
+    if (local_err) {
+        ret = -EINVAL;
+        error_propagate(errp, local_err);
+    }
+fail:
+    qemu_opts_del(opts);
+    return ret;
+}
+
+static void pcache_close(BlockDriverState *bs)
+{
+}
+
+static void pcache_parse_filename(const char *filename, QDict *options,
+                                  Error **errp)
+{
+    qdict_put(options, "x-image", qstring_from_str(filename));
+}
+
+static int64_t pcache_getlength(BlockDriverState *bs)
+{
+    return bdrv_getlength(bs->file->bs);
+}
+
+static bool pcache_recurse_is_first_non_filter(BlockDriverState *bs,
+                                               BlockDriverState *candidate)
+{
+    return bdrv_recurse_is_first_non_filter(bs->file->bs, candidate);
+}
+
+static BlockDriver bdrv_pcache = {
+    .format_name                        = "pcache",
+    .protocol_name                      = "pcache",
+    .instance_size                      = 0,
+
+    .bdrv_parse_filename                = pcache_parse_filename,
+    .bdrv_file_open                     = pcache_file_open,
+    .bdrv_close                         = pcache_close,
+    .bdrv_getlength                     = pcache_getlength,
+
+    .bdrv_co_preadv                     = pcache_co_preadv,
+    .bdrv_co_pwritev                    = pcache_co_pwritev,
+
+    .is_filter                          = true,
+    .bdrv_recurse_is_first_non_filter   = pcache_recurse_is_first_non_filter,
+};
+
+static void bdrv_cache_init(void)
+{
+    bdrv_register(&bdrv_pcache);
+}
+
+block_init(bdrv_cache_init);
-- 
2.10.1




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