Commit ded9d2d5 authored by Paolo Bonzini's avatar Paolo Bonzini Committed by Kevin Wolf
Browse files

qemu-nbd: add --discard option 



Similar to --cache and --aio, this option mimics the discard suboption
of "-drive".

Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: default avatarKevin Wolf <kwolf@redhat.com>
parent a9384aff

qemu-nbd.c

+15 −3
Original line number Diff line number Diff line
@@ -36,6 +36,7 @@ 
#define SOCKET_PATH          "/var/lock/qemu-nbd-%s"

#define QEMU_NBD_OPT_CACHE   1

#define QEMU_NBD_OPT_AIO     2

#define QEMU_NBD_OPT_DISCARD 3



static NBDExport *exp;

static int verbose;
@@ -330,6 +331,7 @@ int main(int argc, char **argv) 
#ifdef CONFIG_LINUX_AIO

        { "aio", 1, NULL, QEMU_NBD_OPT_AIO },

#endif

        { "discard", 1, NULL, QEMU_NBD_OPT_DISCARD },

        { "shared", 1, NULL, 'e' },

        { "persistent", 0, NULL, 't' },

        { "verbose", 0, NULL, 'v' },
@@ -344,6 +346,7 @@ int main(int argc, char **argv) 
    int ret;

    int fd;

    bool seen_cache = false;

    bool seen_discard = false;

#ifdef CONFIG_LINUX_AIO

    bool seen_aio = false;

#endif
@@ -389,6 +392,15 @@ int main(int argc, char **argv) 
            }

            break;

#endif

        case QEMU_NBD_OPT_DISCARD:

            if (seen_discard) {

                errx(EXIT_FAILURE, "--discard can only be specified once");

            }

            seen_discard = true;

            if (bdrv_parse_discard_flags(optarg, &flags) == -1) {

                errx(EXIT_FAILURE, "Invalid discard mode `%s'", optarg);

            }

            break;

        case 'b':

            bindto = optarg;

            break;

qemu-nbd.texi

+4 −0
Original line number Diff line number Diff line
@@ -35,6 +35,10 @@ Export QEMU disk image using NBD protocol. 
@item --aio=@var{aio}

  choose asynchronous I/O mode between @samp{threads} (the default)

  and @samp{native} (Linux only).

@item --discard=@var{discard}

  toggles whether @dfn{discard} (also known as @dfn{trim} or @dfn{unmap})

  requests are ignored or passed to the filesystem.  The default is no

  (@samp{--discard=ignore}).

@item -c, --connect=@var{dev}

  connect @var{filename} to NBD device @var{dev}

@item -d, --disconnect