Christoph Hellwig wrote:
On Sat, Aug 29, 2009 at 08:43:27PM -0400, Douglas Gilbert wrote:
+ if (buffer[14] & 0x80)
+ sdkp->thin_provisioning = 1;
+
So you are checking the TPE bit (Thin Provisioning Enabled) but
not the TPRZ bit (Thin Provisioning Read Zeros). Shouldn't
there also be a sdkp->thin_provisioning_read_zeros bit defined
in struct scsi_disk?
Is your application well defined when TPRZ==0 ?
Filesystems do not care if these blocks are in a defined state, as
they must never return the content of uninitilized blocks to userspace.
Now if we do want to support discard through raid arrays we might start
to care, and will have check the TPRZ bit.
Another reason to note the TPRZ bit is that if it is 1 then
the data given to WRITE SAME (16 and 32) must be a logical
block of zeros for the UNMAP bit to be honoured (sbc3r19.pdf
section 4.6.3.2 last paragraph).
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