| Message ID | 1380029714-5239-14-git-send-email-pl@kamp.de |
|---|---|
| State | New |
| Headers | show |
On 09/24/2013 07:35 AM, Peter Lieven wrote: > this patch adds a call to completely zero out a block device. > the operation is sped up by checking the block status and > only writing zeroes to the device if they currently do not > return zeroes. optionally the zero writing can be sped up > by setting the flag BDRV_REQ_MAY_UNMAP to emulate the zero > write by unmapping if the driver supports it. > > Signed-off-by: Peter Lieven <pl@kamp.de> > --- > block.c | 37 +++++++++++++++++++++++++++++++++++++ > include/block/block.h | 1 + > 2 files changed, 38 insertions(+) > Reviewed-by: Eric Blake <eblake@redhat.com>
On Tue, Sep 24, 2013 at 03:35:07PM +0200, Peter Lieven wrote: > this patch adds a call to completely zero out a block device. > the operation is sped up by checking the block status and > only writing zeroes to the device if they currently do not > return zeroes. optionally the zero writing can be sped up > by setting the flag BDRV_REQ_MAY_UNMAP to emulate the zero > write by unmapping if the driver supports it. > > Signed-off-by: Peter Lieven <pl@kamp.de> > --- > block.c | 37 +++++++++++++++++++++++++++++++++++++ > include/block/block.h | 1 + > 2 files changed, 38 insertions(+) > > diff --git a/block.c b/block.c > index 784e545..66b9eae 100644 > --- a/block.c > +++ b/block.c > @@ -2398,6 +2398,43 @@ int bdrv_write_zeroes(BlockDriverState *bs, int64_t sector_num, > BDRV_REQ_ZERO_WRITE | flags); > } > > +/* > + * Completely zero out a block device with the help of bdrv_write_zeroes. > + * The operation is sped up by checking the block status and only writing > + * zeroes to the device if they currently do not return zeroes. Optional > + * flags are passed through to bdrv_write_zeroes (e.g. BDRV_REQ_MAY_UNMAP). > + * > + * Returns < 0 on error, 0 on success. For error codes see bdrv_write(). > + */ > +int bdrv_zeroize(BlockDriverState *bs, BdrvRequestFlags flags) BlockDriver->bdrv_make_empty() implements zeroing the entire disk for image formats. Please extend that function prototype instead of adding a new interface. Stefan
Am 07.10.2013 um 10:34 schrieb Stefan Hajnoczi <stefanha@gmail.com>: > On Tue, Sep 24, 2013 at 03:35:07PM +0200, Peter Lieven wrote: >> this patch adds a call to completely zero out a block device. >> the operation is sped up by checking the block status and >> only writing zeroes to the device if they currently do not >> return zeroes. optionally the zero writing can be sped up >> by setting the flag BDRV_REQ_MAY_UNMAP to emulate the zero >> write by unmapping if the driver supports it. >> >> Signed-off-by: Peter Lieven <pl@kamp.de> >> --- >> block.c | 37 +++++++++++++++++++++++++++++++++++++ >> include/block/block.h | 1 + >> 2 files changed, 38 insertions(+) >> >> diff --git a/block.c b/block.c >> index 784e545..66b9eae 100644 >> --- a/block.c >> +++ b/block.c >> @@ -2398,6 +2398,43 @@ int bdrv_write_zeroes(BlockDriverState *bs, int64_t sector_num, >> BDRV_REQ_ZERO_WRITE | flags); >> } >> >> +/* >> + * Completely zero out a block device with the help of bdrv_write_zeroes. >> + * The operation is sped up by checking the block status and only writing >> + * zeroes to the device if they currently do not return zeroes. Optional >> + * flags are passed through to bdrv_write_zeroes (e.g. BDRV_REQ_MAY_UNMAP). >> + * >> + * Returns < 0 on error, 0 on success. For error codes see bdrv_write(). >> + */ >> +int bdrv_zeroize(BlockDriverState *bs, BdrvRequestFlags flags) > > BlockDriver->bdrv_make_empty() implements zeroing the entire disk for > image formats. Please extend that function prototype instead of adding > a new interface. You mean, adding bdrv_make_empty as a function to block.c calling drv->bdrv_make_empty if it is defined? Peter > > Stefan
diff --git a/block.c b/block.c index 784e545..66b9eae 100644 --- a/block.c +++ b/block.c @@ -2398,6 +2398,43 @@ int bdrv_write_zeroes(BlockDriverState *bs, int64_t sector_num, BDRV_REQ_ZERO_WRITE | flags); } +/* + * Completely zero out a block device with the help of bdrv_write_zeroes. + * The operation is sped up by checking the block status and only writing + * zeroes to the device if they currently do not return zeroes. Optional + * flags are passed through to bdrv_write_zeroes (e.g. BDRV_REQ_MAY_UNMAP). + * + * Returns < 0 on error, 0 on success. For error codes see bdrv_write(). + */ +int bdrv_zeroize(BlockDriverState *bs, BdrvRequestFlags flags) +{ + int64_t target_size = bdrv_getlength(bs) / BDRV_SECTOR_SIZE; + int64_t ret, nb_sectors, sector_num = 0; + int n; + + for (;;) { + nb_sectors = target_size - sector_num; + if (nb_sectors <= 0) { + return 0; + } + if (nb_sectors > INT_MAX) { + nb_sectors = INT_MAX; + } + ret = bdrv_get_block_status(bs, sector_num, nb_sectors, &n); + if (ret & BDRV_BLOCK_ZERO) { + sector_num += n; + continue; + } + ret = bdrv_write_zeroes(bs, sector_num, n, flags); + if (ret < 0) { + error_report("error writing zeroes at sector %" PRId64 ": %s", + sector_num, strerror(-ret)); + return ret; + } + sector_num += n; + } +} + int bdrv_pread(BlockDriverState *bs, int64_t offset, void *buf, int count1) { diff --git a/include/block/block.h b/include/block/block.h index 2de226f..e059188 100644 --- a/include/block/block.h +++ b/include/block/block.h @@ -196,6 +196,7 @@ int bdrv_write(BlockDriverState *bs, int64_t sector_num, const uint8_t *buf, int nb_sectors); int bdrv_write_zeroes(BlockDriverState *bs, int64_t sector_num, int nb_sectors, BdrvRequestFlags flags); +int bdrv_zeroize(BlockDriverState *bs, BdrvRequestFlags flags); int bdrv_writev(BlockDriverState *bs, int64_t sector_num, QEMUIOVector *qiov); int bdrv_pread(BlockDriverState *bs, int64_t offset, void *buf, int count);
this patch adds a call to completely zero out a block device. the operation is sped up by checking the block status and only writing zeroes to the device if they currently do not return zeroes. optionally the zero writing can be sped up by setting the flag BDRV_REQ_MAY_UNMAP to emulate the zero write by unmapping if the driver supports it. Signed-off-by: Peter Lieven <pl@kamp.de> --- block.c | 37 +++++++++++++++++++++++++++++++++++++ include/block/block.h | 1 + 2 files changed, 38 insertions(+)