Messages in this thread | | | Date | Fri, 29 Sep 2000 14:03:58 +0200 | From | Andries Brouwer <> | Subject | Re: reading 1 hardsector size, not one block size |
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At 00:40 29/09/2000, Matt_Domsch@Dell.com wrote:
> >I'm writing some code to grok the Intel EFI GUID Partition Table structures. > >To to so, my partition reading code (in fs/partitions) needs to be able to > >read one physical sector at a time, particularly the first and last sectors > >on the disk. The bread() function ultimately calls ll_rw_block(), which > >checks that my read size is the same as the block size, which is 1024 for a > >SCSI disk, while the physical sector size is 512 bytes. The EFI Spec calls > >for reading/writing on the physical block size.
You can set the blocksize yourself before reading.
On Fri, Sep 29, 2000 at 02:20:25AM +0100, Anton Altaparmakov wrote:
> And if it has an odd number then you can't read the last sector at all! - > That's what prevents linear raid and proper NTFS support from working on > "odd sized" partitions...
But the question was about reading from disk, not about reading from partition.
> It became apparent that despite that the code in many source files in the > kernel uses BLOCK_SIZE macro it at the same time assumes that it equals > 1024, which is, IMHO, a strange thing to assume to say the least, but > anyway, all those places have to be fixed first.
But BLOCK_SIZE is not what is used. It is only the default. Actual values are in these arrays.
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