bcache: Minor journal fix
bcache: Minor journal fix

The real fix is where we check the bytes we need against how much is
remaining - we also need to check for a journal entry bigger than our
buffer, we'll never write those and it would be bad if we tried to read
one.

Also improve the diagnostic messages.

Signed-off-by: Kent Overstreet <99dffa8a9668ab7f6cde1c94b42a210109971113@daterainc.com>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs