On Fri, Jul 30, 2010 at 04:10:42AM -0400, Christoph Hellwig wrote: > On Thu, Jul 29, 2010 at 06:21:20PM -0400, J. Bruce Fields wrote: > > The readahead cache compensates for the fact that the NFS server > > currently does an open and close on every IO operation in the NFSv2 and > > NFSv3 case. > > > > In the NFSv4 case we have long-lived struct files associated with client > > opens, so there's no need for this. In fact, concurrent IO's using > > trying to modify the same file->f_ra may cause problems. > > Interesting. So why did we get these for v4, but not a file handle > cache for v2 and v3 at the same time? The cases are a little different as we have opens and closes in the v4 protocol to define the lifetime of the cached files. > That would make life for the filesystems a lot easier. What's the main issue for filesystems? I'll see about updating Krishna Kumar's filehandle cache patches from last year. > > if (err) > > goto out; > > err = nfsd_vfs_read(rqstp, fhp, file, offset, vec, vlen, count); > > - } else { > > - err = nfsd_open(rqstp, fhp, S_IFREG, NFSD_MAY_READ, &file); > > - if (err) > > - goto out; > > - err = nfsd_vfs_read(rqstp, fhp, file, offset, vec, vlen, count); > > - nfsd_close(file); > > - } > > + } else > > + err = nfsd_open_read(rqstp, fhp, offset, vec, vlen, count); > > The callers of nfsd_read are: > > fs/nfsd/nfs3proc.c: nfserr = nfsd_read(rqstp, &resp->fh, NULL, > fs/nfsd/nfs4proc.c: /* no need to check permission - this will be done in nfsd_read() */ > fs/nfsd/nfs4xdr.c: nfserr = nfsd_read(read->rd_rqstp, read->rd_fhp, read->rd_filp, > fs/nfsd/nfsproc.c: nfserr = nfsd_read(rqstp, fh_copy(&resp->fh, &argp->fh), NULL, > > which suggests that we're better off just calling nfsd_open_read > (possible with a better name) directly from fs/nfsd/nfs3proc.c and > fs/nfsd/nfsproc.c and nfsd_vfs_read directly from fs/nfsd/nfs4proc.c > and fs/nfsd/nfs4xdr.c instead of doing this conditional. OK, that's a good idea. Maybe nfsd_read() and nfsd_read_file() for the names?? --b. -- 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