| Message ID | 20240611193645.65792-2-cel@kernel.org (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | [v2] NFSD: Support write delegations in LAYOUTGET | expand |
On Tue, Jun 11, 2024 at 03:36:46PM -0400, cel@kernel.org wrote: > From: Chuck Lever <chuck.lever@oracle.com> > > I noticed LAYOUTGET(LAYOUTIOMODE4_RW) returning NFS4ERR_ACCESS > unexpectedly. The NFS client had created a file with mode 0444, and > the server had returned a write delegation on the OPEN(CREATE). The > client was requesting a RW layout using the write delegation stateid > so that it could flush file modifications. > > Creating a read-only file does not seem to be problematic for > NFSv4.1 without pNFS, so I began looking at NFSD's implementation of > LAYOUTGET. > > The failure was because fh_verify() was doing a permission check as > part of verifying the FH presented during the LAYOUTGET. It uses the > loga_iomode value to specify the @accmode argument to fh_verify(). > fh_verify(MAY_WRITE) on a file whose mode is 0444 fails with -EACCES. > > To permit LAYOUT* operations in this case, add OWNER_OVERRIDE when > checking the access permission of the incoming file handle for > LAYOUTGET and LAYOUTCOMMIT. This looks reasonable to me: Reviewed-by: Christoph Hellwig <hch@lst.de>
On Tue, 2024-06-11 at 15:36 -0400, cel@kernel.org wrote: > From: Chuck Lever <chuck.lever@oracle.com> > > I noticed LAYOUTGET(LAYOUTIOMODE4_RW) returning NFS4ERR_ACCESS > unexpectedly. The NFS client had created a file with mode 0444, and > the server had returned a write delegation on the OPEN(CREATE). The > client was requesting a RW layout using the write delegation stateid > so that it could flush file modifications. > > Creating a read-only file does not seem to be problematic for > NFSv4.1 without pNFS, so I began looking at NFSD's implementation of > LAYOUTGET. > > The failure was because fh_verify() was doing a permission check as > part of verifying the FH presented during the LAYOUTGET. It uses the > loga_iomode value to specify the @accmode argument to fh_verify(). > fh_verify(MAY_WRITE) on a file whose mode is 0444 fails with -EACCES. > > To permit LAYOUT* operations in this case, add OWNER_OVERRIDE when > checking the access permission of the incoming file handle for > LAYOUTGET and LAYOUTCOMMIT. > > Cc: Christoph Hellwig <hch@lst.de> > X-Cc: stable@vger.kernel.org # v6.6+ > Message-Id: 4E9C0D74-A06D-4DC3-A48A-73034DC40395@oracle.com > Signed-off-by: Chuck Lever <chuck.lever@oracle.com> > --- > fs/nfsd/nfs4proc.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c > index 46bd20fe5c0f..2e39cf2e502a 100644 > --- a/fs/nfsd/nfs4proc.c > +++ b/fs/nfsd/nfs4proc.c > @@ -2269,7 +2269,7 @@ nfsd4_layoutget(struct svc_rqst *rqstp, > const struct nfsd4_layout_ops *ops; > struct nfs4_layout_stateid *ls; > __be32 nfserr; > - int accmode = NFSD_MAY_READ_IF_EXEC; > + int accmode = NFSD_MAY_READ_IF_EXEC | > NFSD_MAY_OWNER_OVERRIDE; > > switch (lgp->lg_seg.iomode) { > case IOMODE_READ: > @@ -2359,7 +2359,8 @@ nfsd4_layoutcommit(struct svc_rqst *rqstp, > struct nfs4_layout_stateid *ls; > __be32 nfserr; > > - nfserr = fh_verify(rqstp, current_fh, 0, NFSD_MAY_WRITE); > + nfserr = fh_verify(rqstp, current_fh, 0, > + NFSD_MAY_WRITE | > NFSD_MAY_OWNER_OVERRIDE); > if (nfserr) > goto out; > Reviewed-by: Jeff Layton <jlayton@kernel.org>
diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c index 46bd20fe5c0f..2e39cf2e502a 100644 --- a/fs/nfsd/nfs4proc.c +++ b/fs/nfsd/nfs4proc.c @@ -2269,7 +2269,7 @@ nfsd4_layoutget(struct svc_rqst *rqstp, const struct nfsd4_layout_ops *ops; struct nfs4_layout_stateid *ls; __be32 nfserr; - int accmode = NFSD_MAY_READ_IF_EXEC; + int accmode = NFSD_MAY_READ_IF_EXEC | NFSD_MAY_OWNER_OVERRIDE; switch (lgp->lg_seg.iomode) { case IOMODE_READ: @@ -2359,7 +2359,8 @@ nfsd4_layoutcommit(struct svc_rqst *rqstp, struct nfs4_layout_stateid *ls; __be32 nfserr; - nfserr = fh_verify(rqstp, current_fh, 0, NFSD_MAY_WRITE); + nfserr = fh_verify(rqstp, current_fh, 0, + NFSD_MAY_WRITE | NFSD_MAY_OWNER_OVERRIDE); if (nfserr) goto out;