Return-Path: Received: from mail-yk0-f173.google.com ([209.85.160.173]:33897 "EHLO mail-yk0-f173.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751853AbbHTLRk (ORCPT ); Thu, 20 Aug 2015 07:17:40 -0400 Received: by ykdt205 with SMTP id t205so33875227ykd.1 for ; Thu, 20 Aug 2015 04:17:40 -0700 (PDT) From: Jeff Layton To: bfields@fieldses.org Cc: linux-nfs@vger.kernel.org, hch@lst.de, kinglongmee@gmail.com Subject: [PATCH v3 14/20] nfsd: close cached files prior to a REMOVE or RENAME that would replace target Date: Thu, 20 Aug 2015 07:17:14 -0400 Message-Id: <1440069440-27454-15-git-send-email-jeff.layton@primarydata.com> In-Reply-To: <1440069440-27454-1-git-send-email-jeff.layton@primarydata.com> References: <1440069440-27454-1-git-send-email-jeff.layton@primarydata.com> Sender: linux-nfs-owner@vger.kernel.org List-ID: It's not uncommon for some workloads to do a bunch of I/O to a file and delete it just afterward. If knfsd has a cached open file however, then the file may still be open when the dentry is unlinked. If the underlying filesystem is nfs, then that could trigger it to do a sillyrename. On a REMOVE or RENAME scan the nfsd_file cache for open files that correspond to the inode, and proactively unhash and put their references. This should prevent any delete-on-last-close activity from occurring, solely due to knfsd's open file cache. Signed-off-by: Jeff Layton --- fs/nfsd/filecache.c | 25 +++++++++++++++++++++++++ fs/nfsd/filecache.h | 1 + fs/nfsd/trace.h | 17 +++++++++++++++++ fs/nfsd/vfs.c | 17 +++++++++++++++-- 4 files changed, 58 insertions(+), 2 deletions(-) diff --git a/fs/nfsd/filecache.c b/fs/nfsd/filecache.c index e48b536762aa..4bd683f03b6e 100644 --- a/fs/nfsd/filecache.c +++ b/fs/nfsd/filecache.c @@ -283,6 +283,31 @@ nfsd_file_find_locked(struct inode *inode, unsigned int may_flags, return NULL; } +/** + * nfsd_file_close_inode - attempt to forcibly close a nfsd_file + * @inode: inode of the file to attempt to remove + * + * Walk the whole hash bucket, looking for any files that correspond to "inode". + * If any do, then unhash them and put the hashtable reference to them. + */ +void +nfsd_file_close_inode(struct inode *inode) +{ + struct nfsd_file *nf; + struct hlist_node *tmp; + unsigned int hashval = (unsigned int)hash_ptr(inode, NFSD_FILE_HASH_BITS); + LIST_HEAD(dispose); + + spin_lock(&nfsd_file_hashtbl[hashval].nfb_lock); + hlist_for_each_entry_safe(nf, tmp, &nfsd_file_hashtbl[hashval].nfb_head, nf_node) { + if (inode == nf->nf_inode) + nfsd_file_unhash_and_release_locked(nf, &dispose); + } + spin_unlock(&nfsd_file_hashtbl[hashval].nfb_lock); + trace_nfsd_file_close_inode(hashval, inode, !list_empty(&dispose)); + nfsd_file_dispose_list(&dispose); +} + __be32 nfsd_file_acquire(struct svc_rqst *rqstp, struct svc_fh *fhp, unsigned int may_flags, struct nfsd_file **pnf) diff --git a/fs/nfsd/filecache.h b/fs/nfsd/filecache.h index debd558ef786..191cdb25aa66 100644 --- a/fs/nfsd/filecache.h +++ b/fs/nfsd/filecache.h @@ -26,6 +26,7 @@ int nfsd_file_cache_init(void); void nfsd_file_cache_shutdown(void); void nfsd_file_put(struct nfsd_file *nf); struct nfsd_file *nfsd_file_get(struct nfsd_file *nf); +void nfsd_file_close_inode(struct inode *inode); __be32 nfsd_file_acquire(struct svc_rqst *rqstp, struct svc_fh *fhp, unsigned int may_flags, struct nfsd_file **nfp); #endif /* _FS_NFSD_FILECACHE_H */ diff --git a/fs/nfsd/trace.h b/fs/nfsd/trace.h index 2dac872d31e8..95af3b9c7b66 100644 --- a/fs/nfsd/trace.h +++ b/fs/nfsd/trace.h @@ -139,6 +139,23 @@ TRACE_EVENT(nfsd_file_acquire, show_nf_may(__entry->nf_may), __entry->nf_file, be32_to_cpu(__entry->status)) ); + +TRACE_EVENT(nfsd_file_close_inode, + TP_PROTO(unsigned int hash, struct inode *inode, int found), + TP_ARGS(hash, inode, found), + TP_STRUCT__entry( + __field(unsigned int, hash) + __field(struct inode *, inode) + __field(int, found) + ), + TP_fast_assign( + __entry->hash = hash; + __entry->inode = inode; + __entry->found = found; + ), + TP_printk("hash=0x%x inode=0x%p found=%d", __entry->hash, + __entry->inode, __entry->found) +); #endif /* _NFSD_TRACE_H */ #undef TRACE_INCLUDE_PATH diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c index 6cfd96adcc71..98d3b9d96480 100644 --- a/fs/nfsd/vfs.c +++ b/fs/nfsd/vfs.c @@ -1583,6 +1583,15 @@ out_nfserr: goto out_unlock; } +static void +nfsd_close_cached_files(struct dentry *dentry) +{ + struct inode *inode = d_inode(dentry); + + if (inode && S_ISREG(inode->i_mode)) + nfsd_file_close_inode(inode); +} + /* * Rename a file * N.B. After this call _both_ ffhp and tfhp need an fh_put @@ -1652,6 +1661,7 @@ nfsd_rename(struct svc_rqst *rqstp, struct svc_fh *ffhp, char *fname, int flen, if (ffhp->fh_export->ex_path.dentry != tfhp->fh_export->ex_path.dentry) goto out_dput_new; + nfsd_close_cached_files(ndentry); host_err = vfs_rename(fdir, odentry, tdir, ndentry, NULL, 0); if (!host_err) { host_err = commit_metadata(tfhp); @@ -1721,10 +1731,13 @@ nfsd_unlink(struct svc_rqst *rqstp, struct svc_fh *fhp, int type, if (!type) type = d_inode(rdentry)->i_mode & S_IFMT; - if (type != S_IFDIR) + if (type != S_IFDIR) { + nfsd_close_cached_files(rdentry); host_err = vfs_unlink(dirp, rdentry, NULL); - else + } else { host_err = vfs_rmdir(dirp, rdentry); + } + if (!host_err) host_err = commit_metadata(fhp); dput(rdentry); -- 2.4.3