This series fixes up one of the problems that was causing xfs/291
to fail on crc enabled filesystems. basically CRCs were failing on
directory buffers because they weren't being treated as a
discontiguous buffer correctly by prefetch and hence CRCs were only
eve calculated over a portion of the directory block. Hence it threw
lots of errors. Non CRC filesystems threw the same badness on lookup
errors, but repair managed to rebuild the directory buffers
sufficiently for things to work.
Anyway, this patchset fixes the xfs_repair prefetch code to handle
discontiguous buffers and so avoid all the noise that was being
generated and the errors that were being triggered on CRC
This does no make xfs/291 pass on CRC filesystems. Making xfs_reapir
work has pointed out that metadump's handling of multi-block
directory buffers on CRC enable filesystems also appears to be
broken. Fixing that is another patchset, however.