Messages in this thread | | | Date | Tue, 24 Sep 2013 11:07:34 +0800 | From | majianpeng <> | Subject | Re: Re: [PATCH V2 0/2] Auto stop async-write on block device when device removed. |
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>majianpeng <majianpeng@gmail.com> writes: > >> For async-write on block device,if device removed,but the vfs don't know it. >> It will continue to do. >> Patch1 set size of inode of block device to zero when removed disk.By this,vfs know >> disk changed. >> Path2 add size-check on blk_aio_write.If pos of write larger than size of inode,it will >> return zero.So the user can check disk state. > >OK, so the basic problem is that __generic_file_aio_write will always >return 0 after device removal, yes? I'm not sure why that's a real >issue, can you explain exactly why you're trying to change this? > At prenset, the __generic_file_aio_write don't return zero rather that the wanted size. So the user can't know the disk removed. For example: dd if=/dev/zero of=usb-disk bs=64k When removed usb-disk, dd stoped until reached the endof usb-disk.
Using this patch, after removed disk, the aio-write will return zero.I think the upper user will check. (or if the size of block is zero, we return -ENOSPC).
>As for your patches, I don't think that putting the i_size_write into >invalidate_partitions is a good idea. Consider the case of rescanning >partitions: you will always detect a size change now, which is not good. > Yes.But in func rescan_partitions, after invalidate_partitions it will call check_disk_size_change to set size of block_device.
Thanks! Jianpeng Ma >Cheers, >Jeff | |