Date: Mon, 5 Mar 2007 20:08:27 -0600 From: Craig Boston <craig@feniz.gank.org> To: freebsd-stable@freebsd.org Subject: umass media size off-by-one? Message-ID: <20070306020826.GA18228@nowhere>
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Hi all, I ran into this while trying to use geli to encrypt an external usb-2 hard drive. It appears that sometimes the media size reported by umass is one sector too big. For example: umass0: Prolific Technology Inc. Mass Storage Device, rev 2.00/1.00, addr 2 da0 at umass-sim0 bus 0 target 0 lun 0 da0: <WDC WD18 00JB-00DUA0 65.1> Fixed Direct Access SCSI-0 device da0: 40.000MB/s transfers da0: 171705MB (351651889 512 byte sectors: 255H 63S/T 21889C) # dd if=/dev/zero of=/dev/da0 oseek=351651888 count=1 dd: /dev/da0: Input/output error 1+0 records in 0+0 records out 0 bytes transferred in 0.002951 secs (0 bytes/sec) # dd if=/dev/zero of=/dev/da0 oseek=351651887 count=1 1+0 records in 1+0 records out 512 bytes transferred in 0.000982 secs (521360 bytes/sec) This is with a "high speed, power 100 mA, config 1, Mass Storage Device(0x3507), Prolific Technology Inc.(0x067b), rev 1.00" enclosure. I tested with two USB flash memory devices and those seem to report the correct size. I'm currently rebuilding a kernel with USB_DEBUG to see if it's specific to a certain protocol and try to figure out if it's a bug in one of them or if the enclosure is lying. Has anyone run into this before? Craig
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