On Fri, Sep 01, 2017 at 05:16:14PM -0400, J. Bruce Fields wrote:
> On Fri, Sep 01, 2017 at 04:25:53PM -0400, Olga Kornievskaia wrote:
> >
> > > On Sep 1, 2017, at 4:23 PM, J. Bruce Fields <bfields@xxxxxxxxxx> wrote:
> > >
> > > On Thu, Mar 02, 2017 at 11:01:28AM -0500, Olga Kornievskaia wrote:
> > >> From: Andy Adamson <andros@xxxxxxxxxx>
> > >>
> > >> The inter server to server COPY source server filehandle
> > >> is guaranteed to be stale as the COPY is sent to the destination
> > >> server.
> > >
> > > This is definitely not true. That filehandle could very well mean
> > > something to the source server, even if it's just by accident.
> > >
> > > In the case the source filehandle refers to a file on a different
> > > server, nfsd knows that, and should not call fh_verify on it at all.
> >
> > At the time of processing the FH it doesn’t know that there is a COPY
> > operation coming in the compound. So how does it know it refers to
> > a file on a different server?
>
> Sorry, of course you're right, I missed that these filehandles are
> passed by PUTFH and SAVEFH. Yuch.
>
> I don't like that we're doing a filehandle lookup at all on this
> "foreign" filehandle. But maybe it doesn't cause big problems in
> practice.
But could you please check that this does the right thing in practice
if, for example, the source filehandle happens by coincidence to
succesfully verify?
--b.
>
> --b.
>
> >
> > >
> > > --b.
> > >
> > >>
> > >> Signed-off-by: Andy Adamson <andros@xxxxxxxxxx>
> > >> ---
> > >> fs/nfsd/nfs4proc.c | 47 ++++++++++++++++++++++++++++++++++++++++++++++-
> > >> fs/nfsd/nfs4xdr.c | 26 +++++++++++++++++++++++++-
> > >> fs/nfsd/nfsd.h | 2 ++
> > >> fs/nfsd/xdr4.h | 4 ++++
> > >> 4 files changed, 77 insertions(+), 2 deletions(-)
> > >>
> > >> diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
> > >> index a680c8c..733a9aa 100644
> > >> --- a/fs/nfsd/nfs4proc.c
> > >> +++ b/fs/nfsd/nfs4proc.c
> > >> @@ -496,11 +496,19 @@ static __be32 nfsd4_open_omfg(struct svc_rqst *rqstp, struct nfsd4_compound_stat
> > >> nfsd4_putfh(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
> > >> struct nfsd4_putfh *putfh)
> > >> {
> > >> + __be32 ret;
> > >> +
> > >> fh_put(&cstate->current_fh);
> > >> cstate->current_fh.fh_handle.fh_size = putfh->pf_fhlen;
> > >> memcpy(&cstate->current_fh.fh_handle.fh_base, putfh->pf_fhval,
> > >> putfh->pf_fhlen);
> > >> - return fh_verify(rqstp, &cstate->current_fh, 0, NFSD_MAY_BYPASS_GSS);
> > >> + ret = fh_verify(rqstp, &cstate->current_fh, 0, NFSD_MAY_BYPASS_GSS);
> > >> + if (ret == nfserr_stale && HAS_CSTATE_FLAG(cstate, NO_VERIFY_FH)) {
> > >> + CLEAR_CSTATE_FLAG(cstate, NO_VERIFY_FH);
> > >> + SET_CSTATE_FLAG(cstate, IS_STALE_FH);
> > >> + ret = 0;
> > >> + }
> > >> + return ret;
> > >> }
> > >>
> > >> static __be32
> > >> @@ -533,6 +541,16 @@ static __be32 nfsd4_open_omfg(struct svc_rqst *rqstp, struct nfsd4_compound_stat
> > >> nfsd4_savefh(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
> > >> void *arg)
> > >> {
> > >> + /**
> > >> + * This is either an inter COPY (most likely) or an intra COPY with a
> > >> + * stale file handle. If the latter, nfsd4_copy will reset the PUTFH to
> > >> + * return nfserr_stale. No fh_dentry, just copy the file handle
> > >> + * to use with the inter COPY READ.
> > >> + */
> > >> + if (HAS_CSTATE_FLAG(cstate, IS_STALE_FH)) {
> > >> + cstate->save_fh = cstate->current_fh;
> > >> + return nfs_ok;
> > >> + }
> > >> if (!cstate->current_fh.fh_dentry)
> > >> return nfserr_nofilehandle;
> > >>
> > >> @@ -1067,6 +1085,13 @@ static int fill_in_write_vector(struct kvec *vec, struct nfsd4_write *write)
> > >> if (status)
> > >> goto out;
> > >>
> > >> + /* Intra copy source fh is stale. PUTFH will fail with ESTALE */
> > >> + if (HAS_CSTATE_FLAG(cstate, IS_STALE_FH)) {
> > >> + CLEAR_CSTATE_FLAG(cstate, IS_STALE_FH);
> > >> + cstate->status = nfserr_copy_stalefh;
> > >> + goto out_put;
> > >> + }
> > >> +
> > >> bytes = nfsd_copy_file_range(src, copy->cp_src_pos,
> > >> dst, copy->cp_dst_pos, copy->cp_count);
> > >>
> > >> @@ -1081,6 +1106,7 @@ static int fill_in_write_vector(struct kvec *vec, struct nfsd4_write *write)
> > >> status = nfs_ok;
> > >> }
> > >>
> > >> +out_put:
> > >> fput(src);
> > >> fput(dst);
> > >> out:
> > >> @@ -1776,6 +1802,7 @@ static void svcxdr_init_encode(struct svc_rqst *rqstp,
> > >> struct nfsd4_compound_state *cstate = &resp->cstate;
> > >> struct svc_fh *current_fh = &cstate->current_fh;
> > >> struct svc_fh *save_fh = &cstate->save_fh;
> > >> + int i;
> > >> __be32 status;
> > >>
> > >> svcxdr_init_encode(rqstp, resp);
> > >> @@ -1808,6 +1835,12 @@ static void svcxdr_init_encode(struct svc_rqst *rqstp,
> > >> goto encode_op;
> > >> }
> > >>
> > >> + /* NFSv4.2 COPY source file handle may be from a different server */
> > >> + for (i = 0; i < args->opcnt; i++) {
> > >> + op = &args->ops[i];
> > >> + if (op->opnum == OP_COPY)
> > >> + SET_CSTATE_FLAG(cstate, NO_VERIFY_FH);
> > >> + }
> > >> while (!status && resp->opcnt < args->opcnt) {
> > >> op = &args->ops[resp->opcnt++];
> > >>
> > >> @@ -1827,6 +1860,9 @@ static void svcxdr_init_encode(struct svc_rqst *rqstp,
> > >>
> > >> opdesc = OPDESC(op);
> > >>
> > >> + if (HAS_CSTATE_FLAG(cstate, IS_STALE_FH))
> > >> + goto call_op;
> > >> +
> > >> if (!current_fh->fh_dentry) {
> > >> if (!(opdesc->op_flags & ALLOWED_WITHOUT_FH)) {
> > >> op->status = nfserr_nofilehandle;
> > >> @@ -1861,6 +1897,7 @@ static void svcxdr_init_encode(struct svc_rqst *rqstp,
> > >>
> > >> if (opdesc->op_get_currentstateid)
> > >> opdesc->op_get_currentstateid(cstate, &op->u);
> > >> +call_op:
> > >> op->status = opdesc->op_func(rqstp, cstate, &op->u);
> > >>
> > >> if (!op->status) {
> > >> @@ -1881,6 +1918,14 @@ static void svcxdr_init_encode(struct svc_rqst *rqstp,
> > >> status = op->status;
> > >> goto out;
> > >> }
> > >> + /* Only from intra COPY */
> > >> + if (cstate->status == nfserr_copy_stalefh) {
> > >> + dprintk("%s NFS4.2 intra COPY stale src filehandle\n",
> > >> + __func__);
> > >> + status = nfserr_stale;
> > >> + nfsd4_adjust_encode(resp);
> > >> + goto out;
> > >> + }
> > >> if (op->status == nfserr_replay_me) {
> > >> op->replay = &cstate->replay_owner->so_replay;
> > >> nfsd4_encode_replay(&resp->xdr, op);
> > >> diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
> > >> index c632156..328ff9c 100644
> > >> --- a/fs/nfsd/nfs4xdr.c
> > >> +++ b/fs/nfsd/nfs4xdr.c
> > >> @@ -4619,15 +4619,28 @@ __be32 nfsd4_check_resp_size(struct nfsd4_compoundres *resp, u32 respsize)
> > >> return nfserr_rep_too_big;
> > >> }
> > >>
> > >> +/** Rewind the encoding to return nfserr_stale on the PUTFH
> > >> + * in this failed Intra COPY compound
> > >> + */
> > >> +void
> > >> +nfsd4_adjust_encode(struct nfsd4_compoundres *resp)
> > >> +{
> > >> + __be32 *p;
> > >> +
> > >> + p = resp->cstate.putfh_errp;
> > >> + *p++ = nfserr_stale;
> > >> +}
> > >> +
> > >> void
> > >> nfsd4_encode_operation(struct nfsd4_compoundres *resp, struct nfsd4_op *op)
> > >> {
> > >> struct xdr_stream *xdr = &resp->xdr;
> > >> struct nfs4_stateowner *so = resp->cstate.replay_owner;
> > >> + struct nfsd4_compound_state *cstate = &resp->cstate;
> > >> struct svc_rqst *rqstp = resp->rqstp;
> > >> int post_err_offset;
> > >> nfsd4_enc encoder;
> > >> - __be32 *p;
> > >> + __be32 *p, *statp;
> > >>
> > >> p = xdr_reserve_space(xdr, 8);
> > >> if (!p) {
> > >> @@ -4636,9 +4649,20 @@ __be32 nfsd4_check_resp_size(struct nfsd4_compoundres *resp, u32 respsize)
> > >> }
> > >> *p++ = cpu_to_be32(op->opnum);
> > >> post_err_offset = xdr->buf->len;
> > >> + statp = p;
> > >>
> > >> if (op->opnum == OP_ILLEGAL)
> > >> goto status;
> > >> +
> > >> + /** This is a COPY compound with a stale source server file handle.
> > >> + * If OP_COPY processing determines that this is an intra server to
> > >> + * server COPY, then this PUTFH should return nfserr_ stale so the
> > >> + * putfh_errp will be set to nfserr_stale. If this is an inter server
> > >> + * to server COPY, ignore the nfserr_stale.
> > >> + */
> > >> + if (op->opnum == OP_PUTFH && HAS_CSTATE_FLAG(cstate, IS_STALE_FH))
> > >> + cstate->putfh_errp = statp;
> > >> +
> > >> BUG_ON(op->opnum < 0 || op->opnum >= ARRAY_SIZE(nfsd4_enc_ops) ||
> > >> !nfsd4_enc_ops[op->opnum]);
> > >> encoder = nfsd4_enc_ops[op->opnum];
> > >> diff --git a/fs/nfsd/nfsd.h b/fs/nfsd/nfsd.h
> > >> index d966068..8d6fb0f 100644
> > >> --- a/fs/nfsd/nfsd.h
> > >> +++ b/fs/nfsd/nfsd.h
> > >> @@ -272,6 +272,8 @@ static inline bool nfsd4_spo_must_allow(struct svc_rqst *rqstp)
> > >> #define nfserr_replay_me cpu_to_be32(11001)
> > >> /* nfs41 replay detected */
> > >> #define nfserr_replay_cache cpu_to_be32(11002)
> > >> +/* nfs42 intra copy failed with nfserr_stale */
> > >> +#define nfserr_copy_stalefh cpu_to_be32(1103)
> > >>
> > >> /* Check for dir entries '.' and '..' */
> > >> #define isdotent(n, l) (l < 3 && n[0] == '.' && (l == 1 || n[1] == '.'))
> > >> diff --git a/fs/nfsd/xdr4.h b/fs/nfsd/xdr4.h
> > >> index 38fcb4f..aa94295 100644
> > >> --- a/fs/nfsd/xdr4.h
> > >> +++ b/fs/nfsd/xdr4.h
> > >> @@ -45,6 +45,8 @@
> > >>
> > >> #define CURRENT_STATE_ID_FLAG (1<<0)
> > >> #define SAVED_STATE_ID_FLAG (1<<1)
> > >> +#define NO_VERIFY_FH (1<<2)
> > >> +#define IS_STALE_FH (1<<3)
> > >>
> > >> #define SET_CSTATE_FLAG(c, f) ((c)->sid_flags |= (f))
> > >> #define HAS_CSTATE_FLAG(c, f) ((c)->sid_flags & (f))
> > >> @@ -63,6 +65,7 @@ struct nfsd4_compound_state {
> > >> size_t iovlen;
> > >> u32 minorversion;
> > >> __be32 status;
> > >> + __be32 *putfh_errp;
> > >> stateid_t current_stateid;
> > >> stateid_t save_stateid;
> > >> /* to indicate current and saved state id presents */
> > >> @@ -705,6 +708,7 @@ int nfs4svc_decode_compoundargs(struct svc_rqst *, __be32 *,
> > >> int nfs4svc_encode_compoundres(struct svc_rqst *, __be32 *,
> > >> struct nfsd4_compoundres *);
> > >> __be32 nfsd4_check_resp_size(struct nfsd4_compoundres *, u32);
> > >> +void nfsd4_adjust_encode(struct nfsd4_compoundres *);
> > >> void nfsd4_encode_operation(struct nfsd4_compoundres *, struct nfsd4_op *);
> > >> void nfsd4_encode_replay(struct xdr_stream *xdr, struct nfsd4_op *op);
> > >> __be32 nfsd4_encode_fattr_to_buf(__be32 **p, int words,
> > >> --
> > >> 1.8.3.1
> > >>
> >
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