On Fri, 2012-03-30 at 13:12 -0400, Peter Staubach wrote: > Hi. > > I think that the code to allow CREATE operations which end up opening existing, non-regular files is there for diskless operation. > > I vaguely recall some applications specifying O_CREATE to open and expecting the open of a non-regular file, which exists already, to succeed. Yes, and this is what POSIX expects too. The exception is when you open a directory with O_CREATE: that will end up returning EISDIR to the application. Cheers Trond > ps > > > -----Original Message----- > From: linux-nfs-owner@xxxxxxxxxxxxxxx [mailto:linux-nfs-owner@xxxxxxxxxxxxxxx] On Behalf Of Dr James Bruce Fields > Sent: Thursday, March 29, 2012 5:09 PM > To: Myklebust, Trond > Cc: Orion Poplawski; linux-nfs@xxxxxxxxxxxxxxx > Subject: Re: [nfsv4] open(O_CREAT) returns EEXISTS on symbolic link created on another system until stat()ed > > On Thu, Mar 29, 2012 at 08:56:57PM +0000, Myklebust, Trond wrote: > > On Thu, 2012-03-29 at 16:50 -0400, Dr James Bruce Fields wrote: > > > On Thu, Mar 29, 2012 at 08:42:24PM +0000, Myklebust, Trond wrote: > > > > On Thu, 2012-03-29 at 16:16 -0400, Trond Myklebust wrote: > > > > > On Thu, 2012-03-29 at 15:31 -0400, Dr James Bruce Fields wrote: > > > > > > On Thu, Mar 29, 2012 at 12:07:17PM -0600, Orion Poplawski wrote: > > > > > > > On 03/29/2012 11:40 AM, Myklebust, Trond wrote: > > > > > > > >>Going back to v4 on EL5.8 server: nfsv4el.log, > > > > > > > >>nfsv4f18.log > > > > > > > >> > > > > > > > >>Both get NFS4ERR_EXIST in this case. > > > > > > > > > > > > > > > >Which is an obvious server bug: it should be sending > > > > > > > >NFS4ERR_SYMLINK in reply to that OPEN. > > > > > > > > > > > > > > > >Bruce? > > > > > > > > > > > > > > > > > > > > > > I can reproduce with a 3.4.0-0.rc0.git1.2.fc18 server as well. > > > > > > > > > > > > Hm. So how about this? (Untested.) > > > > > > > > > > > > Probably there should be a pynfs test too. > > > > > > > > > > > > I'm assuming it should still be ERR_EXIST in the exclusive, > > > > > > exclusive4_1, and guarded cases. > > > > > > > > > > > > --b. > > > > > > > > > > > > diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c index > > > > > > 7423d71..2bfcad4 100644 > > > > > > --- a/fs/nfsd/vfs.c > > > > > > +++ b/fs/nfsd/vfs.c > > > > > > @@ -1457,9 +1457,12 @@ do_nfsd_create(struct svc_rqst *rqstp, > > > > > > struct svc_fh *fhp, > > > > > > > > > > > > switch (createmode) { > > > > > > case NFS3_CREATE_UNCHECKED: > > > > > > - if (! S_ISREG(dchild->d_inode->i_mode)) > > > > > > - err = nfserr_exist; > > > > > > - else if (truncp) { > > > > > > + if (! S_ISREG(dchild->d_inode->i_mode)) { > > > > > > + if (rqstp->rq_vers == 4) > > > > > > + err = nfserr_symlink; > > > > > > + else > > > > > > + err = nfserr_exist; > > > > > > > > > > No. This should _never_ return NFS4ERR_EXIST. > > > > > > > > > > It should return > > > > > * NFS4ERR_ISDIR if the object is a directory > > > > > * NFS4ERR_SYMLINK if it is symbolic link, > > > > > * either NFS4ERR_WRONG_TYPE (NFSv4.1) or NFS4ERR_SYMLINK (NFSv4.0) > > > > > if the object is any other non-regular file. > > > > > > > > Basically, if an object already exists with that name, then > > > > NFS3_CREATE_UNCHECKED should be treated as if it is an ordinary > > > > OPEN (in the case of NFSv4) or LOOKUP (in the case of NFSv3). > > > > > > Oh, so in the v3 case this should be nfs_ok, and it's up to the > > > client to check attributes on the result and decide what to do? > > > > > > (Is this written down someplace?) > > > > In RFC1813: "UNCHECKED means that the file should be created without > > checking for the existence of a duplicate file in the same directory." > > I don't understand how to apply that sentence to the case of a preexisting non-regular-file in the same directory. > > (Actually, I don't understand it in the case of an existing regular file either--to me "create without checking for existence" sounds like "even if a file already exists, you should clobber it and create a new one > anyway"....) > > Anyway, something like the following (untested) should change v3 to return nfs_ok in this case, and v4 to return the same errors it would on a non-create open. > > --b. > > diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c index 2ed14df..8256efd 100644 > --- a/fs/nfsd/nfs4proc.c > +++ b/fs/nfsd/nfs4proc.c > @@ -235,17 +235,17 @@ do_open_lookup(struct svc_rqst *rqstp, struct svc_fh *current_fh, struct nfsd4_o > */ > if (open->op_createmode == NFS4_CREATE_EXCLUSIVE && status == 0) > open->op_bmval[1] = (FATTR4_WORD1_TIME_ACCESS | > - FATTR4_WORD1_TIME_MODIFY); > + FATTR4_WORD1_TIME_MODIFY); > } else { > status = nfsd_lookup(rqstp, current_fh, > open->op_fname.data, open->op_fname.len, resfh); > fh_unlock(current_fh); > - if (status) > - goto out; > - status = nfsd_check_obj_isreg(resfh); > } > if (status) > goto out; > + status = nfsd_check_obj_isreg(resfh); > + if (status) > + goto out; > > if (is_create_with_attrs(open) && open->op_acl != NULL) > do_set_nfs4_acl(rqstp, resfh, open->op_acl, open->op_bmval); diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c index 7423d71..890f439 100644 > --- a/fs/nfsd/vfs.c > +++ b/fs/nfsd/vfs.c > @@ -1458,7 +1458,7 @@ do_nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp, > switch (createmode) { > case NFS3_CREATE_UNCHECKED: > if (! S_ISREG(dchild->d_inode->i_mode)) > - err = nfserr_exist; > + goto out; > else if (truncp) { > /* in nfsv4, we need to treat this case a little > * differently. we don't want to truncate the > -- > 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 -- Trond Myklebust Linux NFS client maintainer NetApp Trond.Myklebust@xxxxxxxxxx www.netapp.com ��.n��������+%������w��{.n�����{��w��� jg��� �����ݢj����G���� ���j:+v���w�m������w�������h�����٥
