[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Old Index]
On Mon, Feb 22, 2010 at 04:40:58PM -0500, Matthew Mondor wrote:
> After reading the manual page of msync(2), I have the impression that
> if invoked with the MS_SYNC flag, it should be safe enough not to need
> a further fdatasync(2)/fsync_range(2) call afterwards?
That is the theory.
> And how about the metadata? Would sync(2) be the only true way to
> ensure it's synchronized (considering fsync(2) seems fd-specific)?
What metadata? You can't get to things like the time stamps via mmap.
Granted, in FFS-land someone might have thought it made sense to write
out all the data blocks and not the FS-level metadata that describes
them on disk... but since doing this does not guarantee that the data
can be read back again later, it is not a correct implementation of
msync(2). (Or fdatasync(2) either.)
> Also, I am auditing an application which seems to modify mmaped files
> but which does not use msync(2) at all (and I can see that an older
> fsync(2) call was used, but is now commented out). Should this be
> considered a bug?
Why would it be?
David A. Holland
Main Index |
Thread Index |