int
krbd_resize(struct rbd_ctx *ctx, uint64_t size)
{
int ret;
assert(size % truncbdy == 0);
/*
* When krbd detects a size change, it calls revalidate_disk(),
* which ends up calling invalidate_bdev(), which invalidates
* clean pages and does nothing about dirty pages beyond the
* new size. The preceding cache flush makes sure those pages
* are invalidated, which is what we need on shrink:
*
* write 0..1M
* resize 0
* resize 2M
* write 1..2M
*
* results in "data data" rather than "0000 data".
*/
ret = __krbd_flush(ctx);
if (ret < 0)
return ret;
return __librbd_resize(ctx, size);
}
int
krbd_discard(struct rbd_ctx *ctx, uint64_t off, uint64_t len)
{
uint64_t range[2] = { off, len };
int ret;
/*
* BLKDISCARD doesn't affect dirty pages. This means we can't
* rely on discarded sectors to match good_buf (i.e. contain
* zeros) without a preceding cache flush:
*
* write 0..3M
* discard 1..2M
*
* results in "data data data" rather than "data 0000 data".
*/
ret = __krbd_flush(ctx);
if (ret < 0)
return ret;
/*
* off and len must be 512-byte aligned, otherwise BLKDISCARD
* will fail with -EINVAL. This means that -K (enable krbd
* mode) requires -h 512 or similar.
*/
if (ioctl(ctx->krbd_fd, BLKDISCARD, &range) < 0) {
ret = -errno;
prt("BLKDISCARD(%llu, %llu) failed\n", off, len);
return ret;
}
return 0;
}
int
krbd_flatten(struct rbd_ctx *ctx)
{
int ret;
ret = __krbd_flush(ctx);
if (ret < 0)
return ret;
return __librbd_flatten(ctx);
}
int
krbd_clone(struct rbd_ctx *ctx, const char *src_snapname,
const char *dst_imagename, int *order, int stripe_unit,
int stripe_count)
{
int ret;
ret = __krbd_flush(ctx);
if (ret < 0)
return ret;
return __librbd_clone(ctx, src_snapname, dst_imagename, order,
stripe_unit, stripe_count);
}
int
krbd_resize(struct rbd_ctx *ctx, uint64_t size)
{
int ret;
assert(size % truncbdy == 0);
/*
* This is essential: when krbd detects a size change, it calls
* revalidate_disk(), which ends up calling invalidate_bdev(),
* which invalidates only clean buffers. The cache flush makes
* it invalidate everything, which is what we need if we are
* shrinking.
*/
ret = __krbd_flush(ctx);
if (ret < 0)
return ret;
return __librbd_resize(ctx, size);
}
int
krbd_flush(struct rbd_ctx *ctx)
{
return __krbd_flush(ctx);
}
