Re: [Qemu-devel] [PATCH] block/vdi: Limit maximum size even futher

[Max Reitz]

On 2014-10-27 at 12:39, Max Reitz wrote:
> On 2014-10-27 at 12:10, Peter Lieven wrote:
> > On 27.10.2014 11:56, Max Reitz wrote:
> > > The block layer read and write functions do not like requests which are
> > > bigger than INT_MAX bytes. Since the VDI bmap is read and written in a
> > > single operation, its size is therefore limited accordingly. This
> > > reduces the maximum VDI image size supported by QEMU to half of what it
> > > currently is (down to approximately 512 TB).
> > >
> > > The VDI test 084 has to be adapted accordingly. Actually, one could
> > > clearly see that it was broken from the "Could not open
> > > 'TEST_DIR/t.IMGFMT': Invalid argument" line for an image which was
> > > supposed to work just fine.
> > >
> > > Signed-off-by: Max Reitz <address@hidden>
> > > ---
> > > The really funny thing about this is that test 084 still fails after
> > > this patch for me because the computer I am currently working on only
> > > has 4G of main memory (which is exactly what VDI requires for a 512T
> > > image). Any reviewer is therefore kindly asked to test this test
> > > him-/herself; I will do so once I am home (and once I remember to do
> > > it).
> > > ---
> > >   block/vdi.c                |  6 ++++--
> > >   tests/qemu-iotests/084     | 14 +++++++-------
> > >   tests/qemu-iotests/084.out | 13 ++++++++-----
> > >   3 files changed, 19 insertions(+), 14 deletions(-)
> > >
> > > diff --git a/block/vdi.c b/block/vdi.c
> > > index 19701ee..f25e4b5 100644
> > > --- a/block/vdi.c
> > > +++ b/block/vdi.c
> > > @@ -120,8 +120,10 @@ typedef unsigned char uuid_t[16];
> > >     #define VDI_IS_ALLOCATED(X) ((X) < VDI_DISCARDED)
> > >   -/* max blocks in image is (0xffffffff / 4) */
> > > -#define VDI_BLOCKS_IN_IMAGE_MAX  0x3fffffff
> > > +/* The bmap will take up VDI_BLOCKS_IN_IMAGE_MAX * sizeof(uint32_t) 
> > > bytes; since
> > > + * the bmap is read and written in a single operation, its size 
> > > needs to be
> > > + * limited to INT_MAX */
> > > +#define VDI_BLOCKS_IN_IMAGE_MAX  ((unsigned)(INT_MAX / 
> > > sizeof(uint32_t)))
> > Test 084 doesn't work:
> >
> > address@hidden:~/git/qemu/tests/qemu-iotests$ ./check -vdi 084
> > QEMU          -- ./qemu
> > QEMU_IMG      -- ./qemu-img
> > QEMU_IO       -- ./qemu-io
> > QEMU_NBD      -- /home/lieven/git/qemu/tests/qemu-iotests/../../qemu-nbd
> > IMGFMT        -- vdi
> > IMGPROTO      -- file
> > PLATFORM      -- Linux/x86_64 lieven-pc 3.13.0-38-generic
> > SOCKET_SCM_HELPER -- 
> > /home/lieven/git/qemu/tests/qemu-iotests/socket_scm_helper
> >
> > 084 4s ... - output mismatch (see 084.out.bad)
> > --- /home/lieven/git/qemu/tests/qemu-iotests/084.out 2014-10-27 
> > 12:08:40.229116502 +0100
> > +++ 084.out.bad    2014-10-27 12:09:01.516700174 +0100
> > @@ -18,10 +18,7 @@
> >  cluster_size: 1048576
> >  disk image file size in bytes: 1024
> >  Test 1: Maximum size (512 TB):
> > -image: TEST_DIR/t.IMGFMT
> > -file format: IMGFMT
> > -virtual size: 512T (562949952372736 bytes)
> > -cluster_size: 1048576
> > +qemu-img: Could not open 'TEST_DIR/t.IMGFMT': Could not open 
> > 'TEST_DIR/t.IMGFMT': Invalid argument
>
> Thanks, than NACK and I'll see to it at home.

*then

(I can't resist)

> Max
>
> >  Test 2: Size too large (512TB + 1)
> >  qemu-img: Could not open 'TEST_DIR/t.IMGFMT': Unsupported VDI image 
> > size (size is 0x1fffffff10000, max supported is 0x1fffffff00000)
> > Failures: 084
> > Failed 1 of 1 tests
> >
> > Peter
> >
> > >   #define VDI_DISK_SIZE_MAX ((uint64_t)VDI_BLOCKS_IN_IMAGE_MAX * \
> > > (uint64_t)DEFAULT_CLUSTER_SIZE)
> > >   diff --git a/tests/qemu-iotests/084 b/tests/qemu-iotests/084
> > > index 2712c02..9b710e5 100755
> > > --- a/tests/qemu-iotests/084
> > > +++ b/tests/qemu-iotests/084
> > > @@ -66,15 +66,15 @@ stat -c"disk image file size in bytes: %s" 
> > > "${TEST_IMG}"
> > >     # check for image size too large
> > >   # poke max image size, and appropriate blocks_in_image value
> > > -echo "Test 1: Maximum size (1024 TB):"
> > > -poke_file "$TEST_IMG" "$ds_offset" "\x00\x00\xf0\xff\xff\xff\x03\x00"
> > > -poke_file "$TEST_IMG" "$bii_offset" "\xff\xff\xff\x3f"
> > > +echo "Test 1: Maximum size (512 TB):"
> > > +poke_file "$TEST_IMG" "$ds_offset" "\x00\x00\xf0\xff\xff\xff\x01\x00"
> > > +poke_file "$TEST_IMG" "$bii_offset" "\xff\xff\xff\x1f"
> > >   _img_info
> > >     echo
> > > -echo "Test 2: Size too large (1024TB + 1)"
> > > +echo "Test 2: Size too large (512TB + 1)"
> > >   # This should be too large (-EINVAL):
> > > -poke_file "$TEST_IMG" "$ds_offset" "\x00\x00\xf1\xff\xff\xff\x03\x00"
> > > +poke_file "$TEST_IMG" "$ds_offset" "\x00\x00\xf1\xff\xff\xff\x01\x00"
> > >   _img_info
> > >     echo
> > > @@ -89,9 +89,9 @@ _img_info
> > >     echo
> > >   echo "Test 4: Size valid (64M), but Blocks In Image exceeds max 
> > > allowed"
> > > -# Now check the bounds of blocks_in_image - 0x3fffffff should be 
> > > the max
> > > +# Now check the bounds of blocks_in_image - 0x1fffffff should be 
> > > the max
> > >   # value here, and we should get -ENOTSUP
> > > -poke_file "$TEST_IMG" "$bii_offset" "\x00\x00\x00\x40"
> > > +poke_file "$TEST_IMG" "$bii_offset" "\x00\x00\x00\x20"
> > >   _img_info
> > >     # Finally, 1MB is the only block size supported.  Verify that
> > > diff --git a/tests/qemu-iotests/084.out b/tests/qemu-iotests/084.out
> > > index ea29ae0..4ac0157 100644
> > > --- a/tests/qemu-iotests/084.out
> > > +++ b/tests/qemu-iotests/084.out
> > > @@ -17,17 +17,20 @@ file format: IMGFMT
> > >   virtual size: 64M (67108864 bytes)
> > >   cluster_size: 1048576
> > >   disk image file size in bytes: 1024
> > > -Test 1: Maximum size (1024 TB):
> > > -qemu-img: Could not open 'TEST_DIR/t.IMGFMT': Could not open 
> > > 'TEST_DIR/t.IMGFMT': Invalid argument
> > > +Test 1: Maximum size (512 TB):
> > > +image: TEST_DIR/t.IMGFMT
> > > +file format: IMGFMT
> > > +virtual size: 512T (562949952372736 bytes)
> > > +cluster_size: 1048576
> > >   -Test 2: Size too large (1024TB + 1)
> > > -qemu-img: Could not open 'TEST_DIR/t.IMGFMT': Unsupported VDI image 
> > > size (size is 0x3fffffff10000, max supported is 0x3fffffff00000)
> > > +Test 2: Size too large (512TB + 1)
> > > +qemu-img: Could not open 'TEST_DIR/t.IMGFMT': Unsupported VDI image 
> > > size (size is 0x1fffffff10000, max supported is 0x1fffffff00000)
> > >     Test 3: Size valid (64M), but Blocks In Image too small (63)
> > >   qemu-img: Could not open 'TEST_DIR/t.IMGFMT': unsupported VDI 
> > > image (disk size 67108864, image bitmap has room for 66060288)
> > >     Test 4: Size valid (64M), but Blocks In Image exceeds max allowed
> > > -qemu-img: Could not open 'TEST_DIR/t.IMGFMT': unsupported VDI image 
> > > (too many blocks 1073741824, max is 1073741823)
> > > +qemu-img: Could not open 'TEST_DIR/t.IMGFMT': unsupported VDI image 
> > > (too many blocks 536870912, max is 536870911)
> > >     Test 5: Valid Image: 64MB, Blocks In Image 64, Block Size 1MB
> > >   image: TEST_DIR/t.IMGFMT