Commit 215e47b9 authored by Paolo Bonzini's avatar Paolo Bonzini Committed by Kevin Wolf
Browse files

blockdev: enable discard by default 



Because discard is now a host parameter, we can always fake it as enabled
in the guest.  This is an extension of the current choice to ignore
"not supported" errors from the host when discard_granularity is set
to nonzero.

The default granularity is set to the logical block size or 4k, whichever
is largest, because cluster sizes below 4k are rarely used and 4K is a
typical block size for files.

Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: default avatarKevin Wolf <kwolf@redhat.com>
parent ded9d2d5

hw/block-common.h

+1 −1
Original line number Diff line number Diff line
@@ -50,7 +50,7 @@ static inline unsigned int get_physical_block_exp(BlockConf *conf) 
    DEFINE_PROP_UINT32("opt_io_size", _state, _conf.opt_io_size, 0),    \

    DEFINE_PROP_INT32("bootindex", _state, _conf.bootindex, -1),        \

    DEFINE_PROP_UINT32("discard_granularity", _state, \

                       _conf.discard_granularity, 0)

                       _conf.discard_granularity, -1)



#define DEFINE_BLOCK_CHS_PROPERTIES(_state, _conf)      \

    DEFINE_PROP_UINT32("cyls", _state, _conf.cyls, 0),  \

hw/ide/qdev.c

+4 −1
Original line number Diff line number Diff line
@@ -143,7 +143,10 @@ static int ide_dev_initfn(IDEDevice *dev, IDEDriveKind kind) 
    IDEBus *bus = DO_UPCAST(IDEBus, qbus, dev->qdev.parent_bus);

    IDEState *s = bus->ifs + dev->unit;



    if (dev->conf.discard_granularity && dev->conf.discard_granularity != 512) {

    if (dev->conf.discard_granularity == -1) {

        dev->conf.discard_granularity = 512;

    } else if (dev->conf.discard_granularity &&

               dev->conf.discard_granularity != 512) {

        error_report("discard_granularity must be 512 for ide");

        return -1;

    }

hw/scsi-disk.c

+10 −3
Original line number Diff line number Diff line
@@ -45,6 +45,8 @@ do { printf("scsi-disk: " fmt , ## __VA_ARGS__); } while (0) 
#define SCSI_MAX_INQUIRY_LEN        256

#define SCSI_MAX_MODE_LEN           256



#define DEFAULT_DISCARD_GRANULARITY 4096



typedef struct SCSIDiskState SCSIDiskState;



typedef struct SCSIDiskReq {
@@ -2059,6 +2061,11 @@ static int scsi_initfn(SCSIDevice *dev) 
        return -1;

    }



    if (s->qdev.conf.discard_granularity == -1) {

        s->qdev.conf.discard_granularity =

            MAX(s->qdev.conf.logical_block_size, DEFAULT_DISCARD_GRANULARITY);

    }



    if (!s->version) {

        s->version = g_strdup(qemu_get_version());

    }