qemu-devel
[Top][All Lists]
Advanced

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [PATCH v2 3/6] qemu-nbd: add compression flag support


From: Vladimir Sementsov-Ogievskiy
Subject: Re: [PATCH v2 3/6] qemu-nbd: add compression flag support
Date: Mon, 7 Oct 2019 11:52:17 +0000

04.10.2019 13:19, Roman Kagan wrote:
> 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 <address@hidden>
>> Signed-off-by: Vladimir Sementsov-Ogievskiy <address@hidden>
>> Signed-off-by: Denis V. Lunev <address@hidden>
>> Signed-off-by: Andrey Shinkevich <address@hidden>
>> ---
>>   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?
> 

I like the idea. And then we'll deprecate compression option in backup job.


-- 
Best regards,
Vladimir

reply via email to

[Prev in Thread] Current Thread [Next in Thread]