Return-Path: Received: from mail-io0-f195.google.com ([209.85.223.195]:35049 "EHLO mail-io0-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759718AbcLAWTd (ORCPT ); Thu, 1 Dec 2016 17:19:33 -0500 Received: by mail-io0-f195.google.com with SMTP id h133so4680618ioe.2 for ; Thu, 01 Dec 2016 14:19:33 -0800 (PST) From: Trond Myklebust To: linux-nfs@vger.kernel.org Subject: [PATCH 08/26] pNFS: Delay getting the layout header in CB_LAYOUTRECALL handlers Date: Thu, 1 Dec 2016 17:19:04 -0500 Message-Id: <20161201221922.15657-9-trond.myklebust@primarydata.com> In-Reply-To: <20161201221922.15657-8-trond.myklebust@primarydata.com> References: <20161201221922.15657-1-trond.myklebust@primarydata.com> <20161201221922.15657-2-trond.myklebust@primarydata.com> <20161201221922.15657-3-trond.myklebust@primarydata.com> <20161201221922.15657-4-trond.myklebust@primarydata.com> <20161201221922.15657-5-trond.myklebust@primarydata.com> <20161201221922.15657-6-trond.myklebust@primarydata.com> <20161201221922.15657-7-trond.myklebust@primarydata.com> <20161201221922.15657-8-trond.myklebust@primarydata.com> Sender: linux-nfs-owner@vger.kernel.org List-ID: Instead of grabbing the layout, we want to get the inode so that we can reduce races between layoutget and layoutrecall when the server does not support call referring. Signed-off-by: Trond Myklebust --- fs/nfs/callback_proc.c | 99 ++++++++++++++++++++++++++++++++++---------------- 1 file changed, 67 insertions(+), 32 deletions(-) diff --git a/fs/nfs/callback_proc.c b/fs/nfs/callback_proc.c index e9aa235e9d10..f073a6d2c6a5 100644 --- a/fs/nfs/callback_proc.c +++ b/fs/nfs/callback_proc.c @@ -110,20 +110,52 @@ __be32 nfs4_callback_recall(struct cb_recallargs *args, void *dummy, #if defined(CONFIG_NFS_V4_1) /* - * Lookup a layout by filehandle. + * Lookup a layout inode by stateid * - * Note: gets a refcount on the layout hdr and on its respective inode. - * Caller must put the layout hdr and the inode. + * Note: returns a refcount on the inode and superblock + */ +static struct inode *nfs_layout_find_inode_by_stateid(struct nfs_client *clp, + const nfs4_stateid *stateid) +{ + struct nfs_server *server; + struct inode *inode; + struct pnfs_layout_hdr *lo; + +restart: + list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) { + list_for_each_entry(lo, &server->layouts, plh_layouts) { + if (stateid != NULL && + !nfs4_stateid_match_other(stateid, &lo->plh_stateid)) + continue; + inode = igrab(lo->plh_inode); + if (!inode) + continue; + if (!nfs_sb_active(inode->i_sb)) { + rcu_read_lock(); + spin_unlock(&clp->cl_lock); + iput(inode); + spin_lock(&clp->cl_lock); + goto restart; + } + return inode; + } + } + + return NULL; +} + +/* + * Lookup a layout inode by filehandle. + * + * Note: returns a refcount on the inode and superblock * - * TODO: keep track of all layouts (and delegations) in a hash table - * hashed by filehandle. */ -static struct pnfs_layout_hdr * get_layout_by_fh_locked(struct nfs_client *clp, - struct nfs_fh *fh) +static struct inode *nfs_layout_find_inode_by_fh(struct nfs_client *clp, + const struct nfs_fh *fh) { struct nfs_server *server; struct nfs_inode *nfsi; - struct inode *ino; + struct inode *inode; struct pnfs_layout_hdr *lo; restart: @@ -134,37 +166,38 @@ static struct pnfs_layout_hdr * get_layout_by_fh_locked(struct nfs_client *clp, continue; if (nfsi->layout != lo) continue; - ino = igrab(lo->plh_inode); - if (!ino) - break; - spin_lock(&ino->i_lock); - /* Is this layout in the process of being freed? */ - if (nfsi->layout != lo) { - spin_unlock(&ino->i_lock); - iput(ino); + inode = igrab(lo->plh_inode); + if (!inode) + continue; + if (!nfs_sb_active(inode->i_sb)) { + rcu_read_lock(); + spin_unlock(&clp->cl_lock); + iput(inode); + spin_lock(&clp->cl_lock); goto restart; } - pnfs_get_layout_hdr(lo); - spin_unlock(&ino->i_lock); - return lo; + return inode; } } return NULL; } -static struct pnfs_layout_hdr * get_layout_by_fh(struct nfs_client *clp, - struct nfs_fh *fh) +static struct inode *nfs_layout_find_inode(struct nfs_client *clp, + const struct nfs_fh *fh, + const nfs4_stateid *stateid) { - struct pnfs_layout_hdr *lo; + struct inode *inode; spin_lock(&clp->cl_lock); rcu_read_lock(); - lo = get_layout_by_fh_locked(clp, fh); + inode = nfs_layout_find_inode_by_stateid(clp, stateid); + if (!inode) + inode = nfs_layout_find_inode_by_fh(clp, fh); rcu_read_unlock(); spin_unlock(&clp->cl_lock); - return lo; + return inode; } /* @@ -213,18 +246,20 @@ static u32 initiate_file_draining(struct nfs_client *clp, u32 rv = NFS4ERR_NOMATCHING_LAYOUT; LIST_HEAD(free_me_list); - lo = get_layout_by_fh(clp, &args->cbl_fh); - if (!lo) { - trace_nfs4_cb_layoutrecall_file(clp, &args->cbl_fh, NULL, - &args->cbl_stateid, -rv); + ino = nfs_layout_find_inode(clp, &args->cbl_fh, &args->cbl_stateid); + if (!ino) goto out; - } - ino = lo->plh_inode; pnfs_layoutcommit_inode(ino, false); spin_lock(&ino->i_lock); + lo = NFS_I(ino)->layout; + if (!lo) { + spin_unlock(&ino->i_lock); + goto out; + } + pnfs_get_layout_hdr(lo); rv = pnfs_check_callback_stateid(lo, &args->cbl_stateid); if (rv != NFS_OK) goto unlock; @@ -258,10 +293,10 @@ static u32 initiate_file_draining(struct nfs_client *clp, /* Free all lsegs that are attached to commit buckets */ nfs_commit_inode(ino, 0); pnfs_put_layout_hdr(lo); +out: trace_nfs4_cb_layoutrecall_file(clp, &args->cbl_fh, ino, &args->cbl_stateid, -rv); - iput(ino); -out: + nfs_iput_and_deactive(ino); return rv; } -- 2.9.3