Re: [libvirt] [PATCH 1/1] storage: Fix a vol-clone bug for ppc64

On 2013年11月07日 18:41, Ján Tomko wrote: > On 11/07/2013 09:35 AM, Li Zhang wrote: >> Currently, wbytes is defined as size_t type which is 8 bytes on ppc64, >> but args's value in ioctl(fd, args..) in kernel is unsigned int. >> So it will read more 4 bytes by ioctl() with size_t from memory which >> gets a large number and causes out of memory error. > On x86_64 size_t is 8 bytes and int is 4 bytes, I guess this is an > endianness issue. It doesn't look like the endianness issue. It appends more 32 0s to the value. I need to trace kernel to see how this happens. Here is what I get on PPC64. blksz = 0x1000000000000, pbsz = 0x20000000000 Actually, they should be : blksz = 0x10000, pbsz = 0x200 On x86_64, they can get right value.

> >> This patch changes size_t to unsigned int to synchronize with kernel. > The type in the kernel seems to be int: > https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/bloc... > > https://lkml.org/lkml/2013/11/1/620 Ah, you are right, should be int. :) > >> Signed-off-by: Li Zhang <zhlcindy(a)linux.vnet.ibm.com&gt; >> --- >> src/storage/storage_backend.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/src/storage/storage_backend.c b/src/storage/storage_backend.c >> index 4b1b00d..f510080 100644 >> --- a/src/storage/storage_backend.c >> +++ b/src/storage/storage_backend.c >> @@ -135,7 +135,7 @@ virStorageBackendCopyToFD(virStorageVolDefPtr vol, >> int amtread = -1; >> int ret = 0; >> size_t rbytes = READ_BLOCK_SIZE_DEFAULT; >> - size_t wbytes = 0; >> + unsigned int wbytes = 0; >> int interval; >> char *zerobuf = NULL; >> char *buf = NULL; >> > I'll push this with s/unsigned // later, unless someone has a different > opinion. Got it, thanks.