Return-Path: linux-nfs-owner@vger.kernel.org Received: from fieldses.org ([174.143.236.118]:41287 "EHLO fieldses.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760886Ab3DCSzJ (ORCPT ); Wed, 3 Apr 2013 14:55:09 -0400 Date: Wed, 3 Apr 2013 14:55:08 -0400 From: "J. Bruce Fields" To: Yanchuan Nian Cc: linux-nfs@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] nfsd: fix bug on nfs4 stateid deallocation Message-ID: <20130403185508.GE6044@fieldses.org> References: <1362962774-5141-1-git-send-email-ycnian@gmail.com> <20130311150208.GB16309@fieldses.org> <20130402015044.GA12158@fieldses.org> <20130403105843.GA22704@mail.example.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <20130403105843.GA22704@mail.example.com> Sender: linux-nfs-owner@vger.kernel.org List-ID: On Wed, Apr 03, 2013 at 06:58:43PM +0800, Yanchuan Nian wrote: > On Mon, Apr 01, 2013 at 09:50:44PM -0400, J. Bruce Fields wrote: > > On Wed, Mar 13, 2013 at 11:04:54PM +0800, Yanchuan Nian wrote: > > > 2013/3/11 J. Bruce Fields > > > > > > > On Mon, Mar 11, 2013 at 08:46:14AM +0800, ycnian@gmail.com wrote: > > > > > NFS4_OO_PURGE_CLOSE is not handled properly. To avoid memory leak, nfs4 > > > > > stateid which is pointed by oo_last_closed_stid is freed in > > > > nfsd4_close(), > > > > > but NFS4_OO_PURGE_CLOSE isn't cleared meanwhile. So the stateid released > > > > in > > > > > THIS close procedure may be freed immediately in the coming encoding > > > > function. > > > > > > > > OK, makes sense. This code is confusing, I wonder if there's some way > > > > we could make it simpler. > > > > > > > > > > The only purpose of NFS4_OO_PURGE_CLOSE is to decide whether the stateid > > > pointed by last-closed-stateid should be freed or not. I wonder if this > > > flag is necessary. oo_last_closed_stid is set only in CLOSE, so in other > > > procedures, if the pointer is not NULL, it must be set in previous > > > procedure, we can free it directly. In CLOSE procedure, we also free it > > > directly before asigning the new released stateid to it in nfsd4_close(), > > > and then we can ignore it in nfsd4_encode_close(). What do you think? > > > > Yeah, something like that would be simpler, I think. Maybe the > > following? (On top of your patch.) > > This patch may cause memory leak in NFSv4.1. If the stateid released > is the last one in nfs4_openowner, nfs4_openowner will be deallocated > immediately, and NULL will be assigned to cstate->replay_owner at the > same time. In this situation encode_seqid_op_tail() cannot be called. > To avoid this problem, we can free the stateid just before or after > nfs4_opwnowner deallocation. Yes, thanks for catching that!: nfsd4_close_open_stateid(stp); - close->cl_closed_stateid = stp; + if (cstate->minorversion) { + unhash_stid(&stp->st_stid); + free_generic_stateid(stp); + } else + close->cl_closed_stateid = stp; if (list_empty(&oo->oo_owner.so_stateids)) { if (cstate->minorversion) { > Another question, cl_stateid in struct nfsd4_close will be returned to > the client, so original comment is right even though applying this > patch. Can this struct be commented like this. > > struct nfsd4_close { > u32 cl_seqid; /* request */ > stateid_t cl_stateid; /* request+response */ > struct nfs4_ol_stateid *cl_closed_stateid; /* used during processing */ Agreed; done. The result is the following (untested). --b. diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c index 3e1101a..9bd6653 100644 --- a/fs/nfsd/nfs4state.c +++ b/fs/nfsd/nfs4state.c @@ -674,7 +674,7 @@ static void unhash_openowner(struct nfs4_openowner *oo) } } -static void release_last_closed_stateid(struct nfs4_openowner *oo) +void release_last_closed_stateid(struct nfs4_openowner *oo) { struct nfs4_ol_stateid *s = oo->oo_last_closed_stid; @@ -3783,26 +3783,6 @@ out: return status; } -void nfsd4_purge_closed_stateid(struct nfs4_stateowner *so) -{ - struct nfs4_openowner *oo; - struct nfs4_ol_stateid *s; - - if (!so->so_is_open_owner) - return; - oo = openowner(so); - s = oo->oo_last_closed_stid; - if (!s) - return; - if (!(oo->oo_flags & NFS4_OO_PURGE_CLOSE)) { - /* Release the last_closed_stid on the next seqid bump: */ - oo->oo_flags |= NFS4_OO_PURGE_CLOSE; - return; - } - oo->oo_flags &= ~NFS4_OO_PURGE_CLOSE; - release_last_closed_stateid(oo); -} - static void nfsd4_close_open_stateid(struct nfs4_ol_stateid *s) { unhash_open_stateid(s); @@ -3839,9 +3819,11 @@ nfsd4_close(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate, memcpy(&close->cl_stateid, &stp->st_stid.sc_stateid, sizeof(stateid_t)); nfsd4_close_open_stateid(stp); - release_last_closed_stateid(oo); - oo->oo_flags &= ~NFS4_OO_PURGE_CLOSE; - oo->oo_last_closed_stid = stp; + if (cstate->minorversion) { + unhash_stid(&stp->st_stid); + free_generic_stateid(stp); + } else + close->cl_closed_stateid = stp; if (list_empty(&oo->oo_owner.so_stateids)) { if (cstate->minorversion) { diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c index 700de01..60e196f 100644 --- a/fs/nfsd/nfs4xdr.c +++ b/fs/nfsd/nfs4xdr.c @@ -527,6 +527,7 @@ nfsd4_decode_close(struct nfsd4_compoundargs *argp, struct nfsd4_close *close) { DECODE_HEAD; + close->cl_closed_stateid = NULL; READ_BUF(4); READ32(close->cl_seqid); return nfsd4_decode_stateid(argp, &close->cl_stateid); @@ -1707,8 +1708,7 @@ static void write_cinfo(__be32 **p, struct nfsd4_change_info *c) * Note that we increment sequence id's here, at the last moment, so we're sure * we know whether the error to be returned is a sequence id mutating error. */ - -static void encode_seqid_op_tail(struct nfsd4_compoundres *resp, __be32 *save, __be32 nfserr) +static void encode_seqid_op_tail(struct nfsd4_compoundres *resp, __be32 *save, __be32 nfserr, struct nfs4_ol_stateid *close_stp) { struct nfs4_stateowner *stateowner = resp->cstate.replay_owner; @@ -1719,7 +1719,13 @@ static void encode_seqid_op_tail(struct nfsd4_compoundres *resp, __be32 *save, _ (char *)resp->p - (char *)save; memcpy(stateowner->so_replay.rp_buf, save, stateowner->so_replay.rp_buflen); - nfsd4_purge_closed_stateid(stateowner); + if (stateowner->so_is_open_owner) { + struct nfs4_openowner *oo = openowner(stateowner); + + release_last_closed_stateid(oo); + if (close_stp) + oo->oo_last_closed_stid = close_stp; + } } } @@ -2667,7 +2673,7 @@ nfsd4_encode_close(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_c if (!nfserr) nfsd4_encode_stateid(resp, &close->cl_stateid); - encode_seqid_op_tail(resp, save, nfserr); + encode_seqid_op_tail(resp, save, nfserr, close->cl_closed_stateid); return nfserr; } @@ -2770,7 +2776,7 @@ nfsd4_encode_lock(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_lo else if (nfserr == nfserr_denied) nfsd4_encode_lock_denied(resp, &lock->lk_denied); - encode_seqid_op_tail(resp, save, nfserr); + encode_seqid_op_tail(resp, save, nfserr, NULL); return nfserr; } @@ -2790,7 +2796,7 @@ nfsd4_encode_locku(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_l if (!nfserr) nfsd4_encode_stateid(resp, &locku->lu_stateid); - encode_seqid_op_tail(resp, save, nfserr); + encode_seqid_op_tail(resp, save, nfserr, NULL); return nfserr; } @@ -2885,7 +2891,7 @@ nfsd4_encode_open(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_op } /* XXX save filehandle here */ out: - encode_seqid_op_tail(resp, save, nfserr); + encode_seqid_op_tail(resp, save, nfserr, NULL); return nfserr; } @@ -2897,7 +2903,7 @@ nfsd4_encode_open_confirm(struct nfsd4_compoundres *resp, __be32 nfserr, struct if (!nfserr) nfsd4_encode_stateid(resp, &oc->oc_resp_stateid); - encode_seqid_op_tail(resp, save, nfserr); + encode_seqid_op_tail(resp, save, nfserr, NULL); return nfserr; } @@ -2909,7 +2915,7 @@ nfsd4_encode_open_downgrade(struct nfsd4_compoundres *resp, __be32 nfserr, struc if (!nfserr) nfsd4_encode_stateid(resp, &od->od_stateid); - encode_seqid_op_tail(resp, save, nfserr); + encode_seqid_op_tail(resp, save, nfserr, NULL); return nfserr; } diff --git a/fs/nfsd/state.h b/fs/nfsd/state.h index f6ae4db..477f027 100644 --- a/fs/nfsd/state.h +++ b/fs/nfsd/state.h @@ -355,7 +355,6 @@ struct nfs4_openowner { struct nfs4_ol_stateid *oo_last_closed_stid; time_t oo_time; /* time of placement on so_close_lru */ #define NFS4_OO_CONFIRMED 1 -#define NFS4_OO_PURGE_CLOSE 2 #define NFS4_OO_NEW 4 unsigned char oo_flags; }; @@ -363,7 +362,7 @@ struct nfs4_openowner { struct nfs4_lockowner { struct nfs4_stateowner lo_owner; /* must be first element */ struct list_head lo_owner_ino_hash; /* hash by owner,file */ - struct list_head lo_perstateid; /* for lockowners only */ + struct list_head lo_perstateid; struct list_head lo_list; /* for temporary uses */ }; @@ -477,7 +476,7 @@ extern struct nfs4_client_reclaim *nfs4_client_to_reclaim(const char *name, struct nfsd_net *nn); extern bool nfs4_has_reclaimed_state(const char *name, struct nfsd_net *nn); extern void put_client_renew(struct nfs4_client *clp); -extern void nfsd4_purge_closed_stateid(struct nfs4_stateowner *); +extern void release_last_closed_stateid(struct nfs4_openowner *); /* nfs4recover operations */ extern int nfsd4_client_tracking_init(struct net *net); diff --git a/fs/nfsd/xdr4.h b/fs/nfsd/xdr4.h index 40e05e6..4d501db 100644 --- a/fs/nfsd/xdr4.h +++ b/fs/nfsd/xdr4.h @@ -91,7 +91,8 @@ struct nfsd4_access { struct nfsd4_close { u32 cl_seqid; /* request */ - stateid_t cl_stateid; /* request+response */ + stateid_t cl_stateid; /* request */ + struct nfs4_ol_stateid *cl_closed_stateid; /* used during processing */ }; struct nfsd4_commit {