Re: [Qemu-devel] [PATCH v3 1/2] block: posix: Always allocate the first block

2019-08-27 Thread Max Reitz
On 27.08.19 18:58, Max Reitz wrote: > On 27.08.19 03:05, Nir Soffer wrote: >> When creating an image with preallocation "off" or "falloc", the first >> block of the image is typically not allocated. When using Gluster >> storage backed by XFS filesystem, reading this block using direct I/O >> succe

Re: [Qemu-devel] [PATCH v3 1/2] block: posix: Always allocate the first block

2019-08-27 Thread Max Reitz
On 27.08.19 03:05, Nir Soffer wrote: > When creating an image with preallocation "off" or "falloc", the first > block of the image is typically not allocated. When using Gluster > storage backed by XFS filesystem, reading this block using direct I/O > succeeds regardless of request length, fooling

[Qemu-devel] [PATCH v3 1/2] block: posix: Always allocate the first block

2019-08-26 Thread Nir Soffer
When creating an image with preallocation "off" or "falloc", the first block of the image is typically not allocated. When using Gluster storage backed by XFS filesystem, reading this block using direct I/O succeeds regardless of request length, fooling alignment detection. In this case we fallbac