On Thu, Nov 27, 2008 at 02:51:40PM +0000, David Howells wrote: > > Hi Christoph, > > Can you answer some questions about exportfs please? > > (1) In linux/exportfs.h, the description of the encode_fh() op says that > "encode_fh() should return the number of bytes stored or a negative error > code such as %-ENOSPC". > > This, however, contradicts export_encode_fh(), which returns a member of > enum fid_type instead. I presume the docs are wrong, or at least, > unclear. No negative error codes, just 255 (or anything that would give 255 when converted to u8, actually). > (2) Why does exportfs_encode_fh() return the type of the FID? Why not embed > it in the fid struct? It seems that the value has to be handed back to > the decode routine. Take a look at the struct nfs_fhbase_new in include/linux/nfsd/nfsfh.h; we have type information for all components in the beginning, packed together, instead of embedding each into its part of array. > (3) Is fat_encode_fh() allowed to return a value not in the fid_type enum? Yes. That enum is just a bunch of common encoding schemes. The values you are using are entirely[*] up to specific filesystem; these ones are just for common helper functions. [*] other than "255 is reserved for encoding error" -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
