Thanks Chuck, I was not aware of this mount option. I will try it. Thanks! On Thu, 2009-07-09 at 10:10 -0400, Chuck Lever wrote: > On Jul 9, 2009, at 8:34 AM, Hans Kramer wrote: > > Hi, > > > > For some silly reason I have an application that needs to poll for the > > existence of a certain file on a NFS share. > > (This is done from Sybase ASE ;-) > > > > Now I run into the issue of attribute caching. Turning of the > > attribute > > cache with the mount option of -o noac easily solves all the issues. > > > > However, it would be nice if we could still use attribute caching and > > force to invalidate on-demand the attribute cache. > > Since you are only concerned with the existence of a file (and not its > mtime, say). have you considered the new directory cache mount option: > lookupcache=? > > I see it's not mentioned in nfs(8) so you should probably look in > recent archives of this mailing list for information. > > > After a lot of trying, the following solution seems to work for me > > now: > > (pathname is the test file) > > > > #define _GNU_SOURCE > > > > char *copy = strdup(pathname); > > char *path = dirname(copy); > > > > int fd = open(path, O_DIRECTORY); > > if (fd >= 0) > > close(fd); > > > > free(copy); > > > > return access(pathname, F_OK); > > > > Just opening the parent directory with O_DIRECTORY seems to do the > > trick. > > > > My questions: Is this hack going to work under every circumstance or > > could it fail in the future with some update. Is there a ioctl call > > that > > could the the same thing? That is invalidate the parent directory > > cache. > > Or do I miss something completely ?-) > > > > Thanks in advance > > > > Hans > > > > -- > > To unsubscribe from this list: send the line "unsubscribe linux-nfs" > > in > > the body of a message to majordomo@xxxxxxxxxxxxxxx > > More majordomo info at http://vger.kernel.org/majordomo-info.html >
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