Messages in this thread |  | | | Subject | Re: [PATCH 1/1] scsi: retrieve cache mode using ATA_16 if normal routine fails | | From | James Bottomley <> | | Date | Mon, 12 Dec 2011 16:51:07 +0400 |
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On Mon, 2011-12-12 at 16:48 +0530, Amit Sahrawat wrote: > It has been observed that a number of USB HDD's do not respond correctly > to SCSI mode sense command(retrieve caching pages) which results in their > Write Cache being discarded by queue requests i.e., WCE if left set to > '0'(disabled). > This results in a number of Filesystem corruptions, when the device > is unplugged abruptly.
Um, how would knowing the caching type correctly help? If you surprise unplug the device, we can't send a flush to it anyway ...
> So, in order to identify the devices correctly - give it > a last try using ATA_16 after failure from normal routine. > Introduce a mechanism to store write-cache type using /sys/class/ > interface, so that the normal code continues to function without errors. > > Signed-off-by: Amit Sahrawat <amit.sahrawat83@gmail.com> > Signed-off-by: Nam-Jae Jeon <namjae.jeon@samsung.com>
This whole patch looks like a layering violation. Why not just update the SAT layer to translate the MODE SENSE correctly?
James
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