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Re: [Qemu-devel] [PATCH] block: Fix bdrv_is_allocated() for short backin
From: |
Kevin Wolf |
Subject: |
Re: [Qemu-devel] [PATCH] block: Fix bdrv_is_allocated() for short backing files |
Date: |
Wed, 7 May 2014 10:31:12 +0200 |
User-agent: |
Mutt/1.5.21 (2010-09-15) |
Am 06.05.2014 um 21:53 hat Max Reitz geschrieben:
> On 06.05.2014 15:30, Kevin Wolf wrote:
> >bdrv_is_allocated() shouldn't return true for sectors that are
> >unallocated, but after the end of a short backing file, even though
> >such sectors are (correctly) marked as containing zeros.
> >
> >Signed-off-by: Kevin Wolf <address@hidden>
> >---
> > block.c | 8 +++++---
> > include/block/block.h | 11 +++++++----
> > 2 files changed, 12 insertions(+), 7 deletions(-)
> >
> >diff --git a/block.c b/block.c
> >index c90c71a..d3a9906 100644
> >--- a/block.c
> >+++ b/block.c
> >@@ -3883,6 +3883,10 @@ static int64_t coroutine_fn
> >bdrv_co_get_block_status(BlockDriverState *bs,
> > *pnum, pnum);
> > }
> >+ if (ret & (BDRV_BLOCK_DATA | BDRV_BLOCK_ZERO)) {
> >+ ret |= BDRV_BLOCK_ALLOCATED;
> >+ }
> >+
>
> Shouldn't BDRV_BLOCK_ALLOCATED be set in the
> !bs->drv->bdrv_co_get_block_status case as well?
It should. Thanks, I'll send a v2.
> > if (!(ret & BDRV_BLOCK_DATA) && !(ret & BDRV_BLOCK_ZERO)) {
> > if (bdrv_unallocated_blocks_are_zero(bs)) {
> > ret |= BDRV_BLOCK_ZERO;
> >@@ -3959,9 +3963,7 @@ int coroutine_fn bdrv_is_allocated(BlockDriverState
> >*bs, int64_t sector_num,
> > if (ret < 0) {
> > return ret;
> > }
> >- return
> >- (ret & BDRV_BLOCK_DATA) ||
> >- ((ret & BDRV_BLOCK_ZERO) && !bdrv_has_zero_init(bs));
> >+ return (ret & BDRV_BLOCK_ALLOCATED);
> > }
> > /*
> >diff --git a/include/block/block.h b/include/block/block.h
> >index 2fda81c..ad4c7e8 100644
> >--- a/include/block/block.h
> >+++ b/include/block/block.h
> >@@ -116,6 +116,8 @@ typedef enum {
> > /* BDRV_BLOCK_DATA: data is read from bs->file or another file
> > * BDRV_BLOCK_ZERO: sectors read as zero
> > * BDRV_BLOCK_OFFSET_VALID: sector stored in bs->file as raw data
> >+ * BDRV_BLOCK_ALLOCATED: the content of the block is determined by this
> >+ * layer (as opposed to the backing file)
>
> I guess this is above BDRV_BLOCK_RAW (albeit having a greater value)
> because it is not only used internally? (to pick up on the topic of
> OCD :-P)
Because it felt right. This may or may not be equivalent.
Kevin