> Instead of calling xfs_zero_eof with the ilock held only take it internally
> for the minimall required critical section around xfs_bmapi_read. This
> also requires changing the calling convention for xfs_zero_last_block
> slightly. The actual zeroing operation is still serialized by the iolock,
> which must be taken exclusively over the call to xfs_zero_eof.
> We could in fact use a shared lock for the xfs_bmapi_read calls as long as
> the extent list has been read in, but given that we already hold the iolock
> exclusively there is little reason to micro optimize this further.
> Reviewed-by: Dave Chinner<dchinner@...>
> Signed-off-by: Christoph Hellwig<hch@...>