Messages in this thread | | | Date | Fri, 10 Oct 2003 13:54:18 -0400 | Subject | Re: statfs() / statvfs() syscall ballsup... | From | Trond Myklebust <> |
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>>>>> " " == Linus Torvalds <torvalds@osdl.org> writes:
> On Fri, 10 Oct 2003, Joel Becker wrote: >> >> msync() forces write(), like fsync(). It doesn't force read().
> Actually, the kernel has a "readahead(fd, offset, size)" system > call that will start asynchronous read-ahead on any > mapping. After that, just touching the page will obviously map > in and synchronize the result.
That's different. That's just preheating the page cache.
It does nothing for the case Joel mentioned where 2 different nodes are writing to the same device, and you need to force a read in order to resynchronize the page cache. Apart from O_DIRECT, we have nothing in the kernel as it stands that will allow userland to deal with this case.
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