On Wed, Oct 02, 2019 at 05:22:43PM +0300, Andrey Shinkevich wrote:
> Added possibility to write compressed data by using the
> blk_write_compressed. This action has the limitations of the format
> driver. For example we can't write compressed data over other.
>
> $ ./qemu-img create -f qcow2 -o size=10G ./image.qcow2
> $ sudo ./qemu-nbd -c /dev/nbd0 ./image.qcow2
> $ sudo dd if=/dev/sda1 of=/dev/nbd0 bs=10M count=10
> 10+0 records in
> 10+0 records out
> 104857600 bytes (105 MB) copied, 0,0890581 s, 1,2 GB/s
> $ sudo ./qemu-nbd -d /dev/nbd0
> $ du -sh ./image.qcow2
> 101M ./image.qcow2
>
> $ ./qemu-img create -f qcow2 -o size=10G ./image.qcow2
> $ sudo ./qemu-nbd -C -c /dev/nbd0 ./image.qcow2
> $ sudo dd if=/dev/sda1 of=/dev/nbd0 bs=10M count=10
> 10+0 records in
> 10+0 records out
> 104857600 bytes (105 MB) copied, 0,076046 s, 1,4 GB/s
> $ sudo ./qemu-nbd -d /dev/nbd0
> $ du -sh ./image.qcow2
> 5,3M ./image.qcow2
>
> Signed-off-by: Pavel Butsykin <pbutsy...@virtuozzo.com>
> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsement...@virtuozzo.com>
> Signed-off-by: Denis V. Lunev <d...@openvz.org>
> Signed-off-by: Andrey Shinkevich <andrey.shinkev...@virtuozzo.com>
> ---
> blockdev-nbd.c | 8 ++++++--
> include/block/nbd.h | 11 +++++++++--
> nbd/server.c | 14 ++++++++++----
> qemu-nbd.c | 30 ++++++++++++++++++++++++++----
> qemu-nbd.texi | 2 ++
> 5 files changed, 53 insertions(+), 12 deletions(-)
>
> diff --git a/blockdev-nbd.c b/blockdev-nbd.c
> index 6a8b206..e83036b 100644
> --- a/blockdev-nbd.c
> +++ b/blockdev-nbd.c
> @@ -151,6 +151,7 @@ void qmp_nbd_server_add(const char *device, bool
> has_name, const char *name,
> BlockBackend *on_eject_blk;
> NBDExport *exp;
> int64_t len;
> + uint32_t iflags = 0;
> AioContext *aio_context;
>
> if (!nbd_server) {
> @@ -189,9 +190,12 @@ void qmp_nbd_server_add(const char *device, bool
> has_name, const char *name,
> if (bdrv_is_read_only(bs)) {
> writable = false;
> }
> + if (!writable) {
> + iflags = NBD_INTERNAL_FLAG_READONLY | NBD_INTERNAL_FLAG_SHARED;
> + }
>
> - exp = nbd_export_new(bs, 0, len, name, NULL, bitmap, !writable,
> !writable,
> - NULL, false, on_eject_blk, errp);
> + exp = nbd_export_new(bs, 0, len, name, NULL, bitmap, iflags, NULL,
> + on_eject_blk, errp);
> if (!exp) {
> goto out;
> }
> diff --git a/include/block/nbd.h b/include/block/nbd.h
> index 316fd70..80be9d5 100644
> --- a/include/block/nbd.h
> +++ b/include/block/nbd.h
> @@ -25,6 +25,13 @@
> #include "crypto/tlscreds.h"
> #include "qapi/error.h"
>
> +enum {
> + NBD_INTERNAL_FLAG_READONLY = 1 << 0, /* Device is read-only */
> + NBD_INTERNAL_FLAG_SHARED = 1 << 1, /* Device can be shared */
> + NBD_INTERNAL_FLAG_WRITETHROUGH = 1 << 2, /* Enable write cache */
> + NBD_INTERNAL_FLAG_COMPRESS = 1 << 3, /* Use compressed write */
> +};
> +
> /* Handshake phase structs - this struct is passed on the wire */
>
> struct NBDOption {
> @@ -330,8 +337,8 @@ typedef struct NBDClient NBDClient;
>
> NBDExport *nbd_export_new(BlockDriverState *bs, uint64_t dev_offset,
> uint64_t size, const char *name, const char *desc,
> - const char *bitmap, bool readonly, bool shared,
> - void (*close)(NBDExport *), bool writethrough,
> + const char *bitmap, uint32_t iflags,
> + void (*close)(NBDExport *),
> BlockBackend *on_eject_blk, Error **errp);
> void nbd_export_close(NBDExport *exp);
> void nbd_export_remove(NBDExport *exp, NbdServerRemoveMode mode, Error
> **errp);
> diff --git a/nbd/server.c b/nbd/server.c
> index d8d1e62..cf3b75d 100644
> --- a/nbd/server.c
> +++ b/nbd/server.c
> @@ -91,6 +91,7 @@ struct NBDExport {
> uint16_t nbdflags;
> QTAILQ_HEAD(, NBDClient) clients;
> QTAILQ_ENTRY(NBDExport) next;
> + uint32_t iflags;
>
> AioContext *ctx;
>
> @@ -1471,13 +1472,14 @@ static void nbd_eject_notifier(Notifier *n, void
> *data)
>
> NBDExport *nbd_export_new(BlockDriverState *bs, uint64_t dev_offset,
> uint64_t size, const char *name, const char *desc,
> - const char *bitmap, bool readonly, bool shared,
> - void (*close)(NBDExport *), bool writethrough,
> + const char *bitmap, uint32_t iflags,
> + void (*close)(NBDExport *),
> BlockBackend *on_eject_blk, Error **errp)
> {
> AioContext *ctx;
> BlockBackend *blk;
> NBDExport *exp = g_new0(NBDExport, 1);
> + bool readonly = iflags & NBD_INTERNAL_FLAG_READONLY;
> uint64_t perm;
> int ret;
>
> @@ -1504,7 +1506,7 @@ NBDExport *nbd_export_new(BlockDriverState *bs,
> uint64_t dev_offset,
> if (ret < 0) {
> goto fail;
> }
> - blk_set_enable_write_cache(blk, !writethrough);
> + blk_set_enable_write_cache(blk, !(iflags &
> NBD_INTERNAL_FLAG_WRITETHROUGH));
> blk_set_allow_aio_context_change(blk, true);
>
> exp->refcount = 1;
> @@ -1518,13 +1520,14 @@ NBDExport *nbd_export_new(BlockDriverState *bs,
> uint64_t dev_offset,
> NBD_FLAG_SEND_FUA | NBD_FLAG_SEND_CACHE);
> if (readonly) {
> exp->nbdflags |= NBD_FLAG_READ_ONLY;
> - if (shared) {
> + if (iflags & NBD_INTERNAL_FLAG_SHARED) {
> exp->nbdflags |= NBD_FLAG_CAN_MULTI_CONN;
> }
> } else {
> exp->nbdflags |= (NBD_FLAG_SEND_TRIM | NBD_FLAG_SEND_WRITE_ZEROES |
> NBD_FLAG_SEND_FAST_ZERO);
> }
> + exp->iflags = iflags;
> assert(size <= INT64_MAX - dev_offset);
> exp->size = QEMU_ALIGN_DOWN(size, BDRV_SECTOR_SIZE);
>
> @@ -2312,6 +2315,9 @@ static coroutine_fn int nbd_handle_request(NBDClient
> *client,
> if (request->flags & NBD_CMD_FLAG_FUA) {
> flags |= BDRV_REQ_FUA;
> }
> + if (exp->iflags & NBD_INTERNAL_FLAG_COMPRESS) {
> + flags |= BDRV_REQ_WRITE_COMPRESSED;
> + }
> ret = blk_pwrite(exp->blk, request->from + exp->dev_offset,
> data, request->len, flags);
> return nbd_send_generic_reply(client, request->handle, ret,
> diff --git a/qemu-nbd.c b/qemu-nbd.c
> index 9032b6d..4163135 100644
> --- a/qemu-nbd.c
> +++ b/qemu-nbd.c
> @@ -139,6 +139,7 @@ static void usage(const char *name)
> " --discard=MODE set discard mode (ignore, unmap)\n"
> " --detect-zeroes=MODE set detect-zeroes mode (off, on, unmap)\n"
> " --image-opts treat FILE as a full set of image options\n"
> +" -C, --compress use data compression (if the target format
> supports it)\n"
> "\n"
> QEMU_HELP_BOTTOM "\n"
> , name, name, NBD_DEFAULT_PORT, "DEVICE");
> @@ -602,6 +603,7 @@ int main(int argc, char **argv)
> BlockDriverState *bs;
> uint64_t dev_offset = 0;
> bool readonly = false;
> + uint32_t iflags = 0;
> bool disconnect = false;
> const char *bindto = NULL;
> const char *port = NULL;
> @@ -610,7 +612,7 @@ int main(int argc, char **argv)
> int64_t fd_size;
> QemuOpts *sn_opts = NULL;
> const char *sn_id_or_name = NULL;
> - const char *sopt = "hVb:o:p:rsnP:c:dvk:e:f:tl:x:T:D:B:L";
> + const char *sopt = "hVb:o:p:rsnCP:c:dvk:e:f:tl:x:T:D:B:L";
> struct option lopt[] = {
> { "help", no_argument, NULL, 'h' },
> { "version", no_argument, NULL, 'V' },
> @@ -619,6 +621,7 @@ int main(int argc, char **argv)
> { "socket", required_argument, NULL, 'k' },
> { "offset", required_argument, NULL, 'o' },
> { "read-only", no_argument, NULL, 'r' },
> + { "compress", no_argument, NULL, 'C'},
> { "partition", required_argument, NULL, 'P' },
> { "bitmap", required_argument, NULL, 'B' },
> { "connect", required_argument, NULL, 'c' },
> @@ -786,6 +789,9 @@ int main(int argc, char **argv)
> readonly = true;
> flags &= ~BDRV_O_RDWR;
> break;
> + case 'C':
> + iflags |= NBD_INTERNAL_FLAG_COMPRESS;
> + break;
> case 'P':
> warn_report("The '-P' option is deprecated; use --image-opts
> with "
> "a raw device wrapper for subset exports instead");
> @@ -1117,6 +1123,14 @@ int main(int argc, char **argv)
>
> blk_set_enable_write_cache(blk, !writethrough);
>
> + if ((iflags & NBD_INTERNAL_FLAG_COMPRESS) &&
> + !(bs->drv && bs->drv->bdrv_co_pwritev_compressed_part))
> + {
> + error_report("Compression not supported for this file format %s",
> + argv[optind]);
> + exit(EXIT_FAILURE);
> + }
> +
> if (sn_opts) {
> ret = bdrv_snapshot_load_tmp(bs,
> qemu_opt_get(sn_opts, SNAPSHOT_OPT_ID),
> @@ -1173,10 +1187,18 @@ int main(int argc, char **argv)
> fd_size = limit;
> }
>
> + if (writethrough) {
> + iflags |= NBD_INTERNAL_FLAG_WRITETHROUGH;
> + }
> + if (readonly) {
> + iflags |= NBD_INTERNAL_FLAG_READONLY;
> + }
> + if (shared > 1) {
> + iflags |= NBD_INTERNAL_FLAG_SHARED;
> + }
> export = nbd_export_new(bs, dev_offset, fd_size, export_name,
> - export_description, bitmap, readonly, shared > 1,
> - nbd_export_closed, writethrough, NULL,
> - &error_fatal);
> + export_description, bitmap, iflags,
> + nbd_export_closed, NULL, &error_fatal);
>
> if (device) {
> #if HAVE_NBD_DEVICE
> diff --git a/qemu-nbd.texi b/qemu-nbd.texi
> index 7f55657..26ea1ec 100644
> --- a/qemu-nbd.texi
> +++ b/qemu-nbd.texi
> @@ -55,6 +55,8 @@ Force the use of the block driver for format @var{fmt}
> instead of
> auto-detecting.
> @item -r, --read-only
> Export the disk as read-only.
> +@item -C, --compress
> +Use data compression (if the target format supports it)
> @item -P, --partition=@var{num}
> Deprecated: Only expose MBR partition @var{num}. Understands physical
> partitions 1-4 and logical partition 5. New code should instead use
I wonder if we're better off adding a generic blockdev option instead,
so that all tools can benefit from it?
Roman.
