Commit 409ef9eb authored by Peter Maydell's avatar Peter Maydell
Browse files

Merge remote-tracking branch 'remotes/ericb/tags/pull-nbd-2018-06-20-v2' into staging 



nbd patches for 2018-06-20

Add experimental x-nbd-server-add-bitmap to expose a disabled
bitmap over NBD, in preparation for a pull model incremental
backup scheme. Also fix a corner case protocol issue with
NBD_CMD_BLOCK_STATUS, and add new NBD_CMD_CACHE.

- Eric Blake: tests: Simplify .gitignore
- Eric Blake: nbd/server: Reject 0-length block status request
- Vladimir Sementsov-Ogievskiy: 0/6 NBD export bitmaps
- Vladimir Sementsov-Ogievskiy: nbd/server: introduce NBD_CMD_CACHE

# gpg: Signature made Thu 21 Jun 2018 15:53:55 BST
# gpg:                using RSA key A7A16B4A2527436A
# gpg: Good signature from "Eric Blake <eblake@redhat.com>"
# gpg:                 aka "Eric Blake (Free Software Programmer) <ebb9@byu.net>"
# gpg:                 aka "[jpeg image of size 6874]"
# Primary key fingerprint: 71C2 CC22 B1C4 6029 27D2  F3AA A7A1 6B4A 2527 436A

* remotes/ericb/tags/pull-nbd-2018-06-20-v2:
  nbd/server: introduce NBD_CMD_CACHE
  docs/interop: add nbd.txt
  qapi: new qmp command nbd-server-add-bitmap
  nbd/server: implement dirty bitmap export
  nbd/server: add nbd_meta_empty_or_pattern helper
  nbd/server: refactor NBDExportMetaContexts
  nbd/server: fix trace
  nbd/server: Reject 0-length block status request
  tests: Simplify .gitignore

Signed-off-by: default avatarPeter Maydell <peter.maydell@linaro.org>
parents 33836a73 bc37b06a

MAINTAINERS

+1 −0
Original line number Diff line number Diff line
@@ -1972,6 +1972,7 @@ F: nbd/ 
F: include/block/nbd*

F: qemu-nbd.*

F: blockdev-nbd.c

F: docs/interop/nbd.txt

T: git git://repo.or.cz/qemu/ericb.git nbd



NFS

blockdev-nbd.c

+23 −0
Original line number Diff line number Diff line
@@ -220,3 +220,26 @@ void qmp_nbd_server_stop(Error **errp) 
    nbd_server_free(nbd_server);

    nbd_server = NULL;

}



void qmp_x_nbd_server_add_bitmap(const char *name, const char *bitmap,

                                 bool has_bitmap_export_name,

                                 const char *bitmap_export_name,

                                 Error **errp)

{

    NBDExport *exp;



    if (!nbd_server) {

        error_setg(errp, "NBD server not running");

        return;

    }



    exp = nbd_export_find(name);

    if (exp == NULL) {

        error_setg(errp, "Export '%s' is not found", name);

        return;

    }



    nbd_export_bitmap(exp, bitmap,

                      has_bitmap_export_name ? bitmap_export_name : bitmap,

                      errp);

}

docs/interop/nbd.txt

0 → 100644
+38 −0
Original line number Diff line number Diff line 
Qemu supports the NBD protocol, and has an internal NBD client (see

block/nbd.c), an internal NBD server (see blockdev-nbd.c), and an

external NBD server tool (see qemu-nbd.c). The common code is placed

in nbd/*.



The NBD protocol is specified here:

https://github.com/NetworkBlockDevice/nbd/blob/master/doc/proto.md



The following paragraphs describe some specific properties of NBD

protocol realization in Qemu.



= Metadata namespaces =



Qemu supports the "base:allocation" metadata context as defined in the

NBD protocol specification, and also defines an additional metadata

namespace "qemu".





== "qemu" namespace ==



The "qemu" namespace currently contains only one type of context,

related to exposing the contents of a dirty bitmap alongside the

associated disk contents.  That context has the following form:



    qemu:dirty-bitmap:<dirty-bitmap-export-name>



Each dirty-bitmap metadata context defines only one flag for extents

in reply for NBD_CMD_BLOCK_STATUS:



    bit 0: NBD_STATE_DIRTY, means that the extent is "dirty"



For NBD_OPT_LIST_META_CONTEXT the following queries are supported

in addition to "qemu:dirty-bitmap:<dirty-bitmap-export-name>":



* "qemu:" - returns list of all available metadata contexts in the

            namespace.

* "qemu:dirty-bitmap:" - returns list of all available dirty-bitmap

                         metadata contexts.

include/block/nbd.h

+8 −3
Original line number Diff line number Diff line
@@ -135,6 +135,7 @@ typedef struct NBDExtent { 
#define NBD_FLAG_SEND_TRIM         (1 << 5) /* Send TRIM (discard) */

#define NBD_FLAG_SEND_WRITE_ZEROES (1 << 6) /* Send WRITE_ZEROES */

#define NBD_FLAG_SEND_DF           (1 << 7) /* Send DF (Do not Fragment) */

#define NBD_FLAG_SEND_CACHE        (1 << 8) /* Send CACHE (prefetch) */



/* New-style handshake (global) flags, sent from server to client, and

   control what will happen during handshake phase. */
@@ -195,7 +196,7 @@ enum { 
    NBD_CMD_DISC = 2,

    NBD_CMD_FLUSH = 3,

    NBD_CMD_TRIM = 4,

    /* 5 reserved for failed experiment NBD_CMD_CACHE */

    NBD_CMD_CACHE = 5,

    NBD_CMD_WRITE_ZEROES = 6,

    NBD_CMD_BLOCK_STATUS = 7,

};
@@ -229,11 +230,13 @@ enum { 
#define NBD_REPLY_TYPE_ERROR         NBD_REPLY_ERR(1)

#define NBD_REPLY_TYPE_ERROR_OFFSET  NBD_REPLY_ERR(2)



/* Flags for extents (NBDExtent.flags) of NBD_REPLY_TYPE_BLOCK_STATUS,

 * for base:allocation meta context */

/* Extent flags for base:allocation in NBD_REPLY_TYPE_BLOCK_STATUS */

#define NBD_STATE_HOLE (1 << 0)

#define NBD_STATE_ZERO (1 << 1)



/* Extent flags for qemu:dirty-bitmap in NBD_REPLY_TYPE_BLOCK_STATUS */

#define NBD_STATE_DIRTY (1 << 0)



static inline bool nbd_reply_type_is_error(int type)

{

    return type & (1 << 15);
@@ -315,6 +318,8 @@ void nbd_client_put(NBDClient *client); 
void nbd_server_start(SocketAddress *addr, const char *tls_creds,

                      Error **errp);



void nbd_export_bitmap(NBDExport *exp, const char *bitmap,

                       const char *bitmap_export_name, Error **errp);



/* nbd_read

 * Reads @size bytes from @ioc. Returns 0 on success.

nbd/common.c

+2 −0
Original line number Diff line number Diff line
@@ -148,6 +148,8 @@ const char *nbd_cmd_lookup(uint16_t cmd) 
        return "flush";

    case NBD_CMD_TRIM:

        return "trim";

    case NBD_CMD_CACHE:

        return "cache";

    case NBD_CMD_WRITE_ZEROES:

        return "write zeroes";

    case NBD_CMD_BLOCK_STATUS: