Return-Path: Received: from mail-yk0-f182.google.com ([209.85.160.182]:33392 "EHLO mail-yk0-f182.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751305AbbHEVN5 (ORCPT ); Wed, 5 Aug 2015 17:13:57 -0400 Received: by ykoo205 with SMTP id o205so46667409yko.0 for ; Wed, 05 Aug 2015 14:13:56 -0700 (PDT) From: Jeff Layton To: bfields@fieldses.org Cc: linux-nfs@vger.kernel.org Subject: [PATCH v2 18/18] nfsd: call flush_delayed_fput from nfsd_file_close_fh Date: Wed, 5 Aug 2015 17:13:36 -0400 Message-Id: <1438809216-4846-19-git-send-email-jeff.layton@primarydata.com> In-Reply-To: <1438809216-4846-1-git-send-email-jeff.layton@primarydata.com> References: <1438264341-18048-1-git-send-email-jeff.layton@primarydata.com> <1438809216-4846-1-git-send-email-jeff.layton@primarydata.com> Sender: linux-nfs-owner@vger.kernel.org List-ID: ...when there are open files to be closed. When knfsd does an fput(), it gets queued to a list and a workqueue job is then scheduled to do the actual __fput work. In the case of knfsd closing down the file prior to a REMOVE or RENAME, we really want to ensure that those files are closed prior to returning. When there are files to be closed, call flush_delayed_fput to ensure this. There are deadlock possibilities if you call flush_delayed_fput while holding locks, however. In the case of nfsd_rename, we don't even do the lookups of the dentries to be renamed until we've locked for rename. Once we've figured out what the target dentry is for a rename, check to see whether there are cached open files associated with it. If there are, then unwind all of the locking, close them all, and then reattempt the rename. Signed-off-by: Jeff Layton --- fs/file_table.c | 1 + fs/nfsd/filecache.c | 33 ++++++++++++++++++++++++++++++++- fs/nfsd/filecache.h | 1 + fs/nfsd/trace.h | 10 +++++++++- fs/nfsd/vfs.c | 52 ++++++++++++++++++++++++++++++++++++++++++++-------- 5 files changed, 87 insertions(+), 10 deletions(-) diff --git a/fs/file_table.c b/fs/file_table.c index 7f9d407c7595..33898e72618c 100644 --- a/fs/file_table.c +++ b/fs/file_table.c @@ -257,6 +257,7 @@ void flush_delayed_fput(void) { delayed_fput(NULL); } +EXPORT_SYMBOL_GPL(flush_delayed_fput); static DECLARE_DELAYED_WORK(delayed_fput_work, delayed_fput); diff --git a/fs/nfsd/filecache.c b/fs/nfsd/filecache.c index a114f3a69117..ce8b8e4f7cf3 100644 --- a/fs/nfsd/filecache.c +++ b/fs/nfsd/filecache.c @@ -273,6 +273,34 @@ nfsd_file_find_locked(struct knfsd_fh *fh, unsigned int may_flags, } /** + * nfsd_file_is_cached - are there any cached open files for this fh? + * @fh: filehandle of the file to check + * + * Scan the hashtable for open files that match this fh. Returns true if there + * are any, and false if not. + */ +bool +nfsd_file_is_cached(struct knfsd_fh *fh) +{ + bool ret = false; + struct nfsd_file *nf; + unsigned int hashval = file_hashval(fh); + + rcu_read_lock(); + hlist_for_each_entry_rcu(nf, &nfsd_file_hashtbl[hashval].nfb_head, + nf_node) { + if (fh_match(&nf->nf_handle, fh)) { + ret = true; + break; + } + } + rcu_read_unlock(); + trace_nfsd_file_is_cached(hashval, fh, (int)ret); + return ret; +} + + +/** * nfsd_file_force_close - attempt to forcibly close a nfsd_file * @fh: filehandle of the file to attempt to remove * @@ -296,7 +324,10 @@ nfsd_file_close_fh(struct knfsd_fh *fh) } spin_unlock(&nfsd_file_hashtbl[hashval].nfb_lock); trace_nfsd_file_close_fh(hashval, fh, !list_empty(&dispose)); - nfsd_file_dispose_list(&dispose); + if (!list_empty(&dispose)) { + nfsd_file_dispose_list(&dispose); + flush_delayed_fput(); + } } __be32 diff --git a/fs/nfsd/filecache.h b/fs/nfsd/filecache.h index 40c47cac2c33..2a347e16f095 100644 --- a/fs/nfsd/filecache.h +++ b/fs/nfsd/filecache.h @@ -44,6 +44,7 @@ int nfsd_file_cache_init(void); void nfsd_file_cache_purge(void); void nfsd_file_cache_shutdown(void); void nfsd_file_put(struct nfsd_file *nf); +bool nfsd_file_is_cached(struct knfsd_fh *fh); void nfsd_file_close_fh(struct knfsd_fh *fh); __be32 nfsd_file_acquire(struct svc_rqst *rqstp, struct svc_fh *fhp, unsigned int may_flags, struct nfsd_file **nfp); diff --git a/fs/nfsd/trace.h b/fs/nfsd/trace.h index c45d318e3a0b..150ce332fbd7 100644 --- a/fs/nfsd/trace.h +++ b/fs/nfsd/trace.h @@ -148,7 +148,7 @@ TRACE_EVENT(nfsd_file_acquire, __entry->nf_file, be32_to_cpu(__entry->status)) ); -TRACE_EVENT(nfsd_file_close_fh, +DECLARE_EVENT_CLASS(nfsd_file_search_class, TP_PROTO(unsigned int hash, struct knfsd_fh *handle, int found), TP_ARGS(hash, handle, found), TP_STRUCT__entry( @@ -164,6 +164,14 @@ TRACE_EVENT(nfsd_file_close_fh, TP_printk("hash=0x%x handle=%s found=%d", __entry->hash, show_nf_fh(__entry->handle), __entry->found) ); + +#define DEFINE_NFSD_FILE_SEARCH_EVENT(name) \ +DEFINE_EVENT(nfsd_file_search_class, name, \ + TP_PROTO(unsigned int hash, struct knfsd_fh *handle, int found), \ + TP_ARGS(hash, handle, found)) + +DEFINE_NFSD_FILE_SEARCH_EVENT(nfsd_file_close_fh); +DEFINE_NFSD_FILE_SEARCH_EVENT(nfsd_file_is_cached); #endif /* _NFSD_TRACE_H */ #undef TRACE_INCLUDE_PATH diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c index c70c6fbec4d7..464e524e8f6e 100644 --- a/fs/nfsd/vfs.c +++ b/fs/nfsd/vfs.c @@ -1596,6 +1596,22 @@ nfsd_close_cached_files(struct dentry *dentry, struct svc_fh *fhp) return err; } +static bool +nfsd_has_cached_files(struct dentry *dentry, struct svc_fh *fhp) +{ + __be32 err; + bool ret = false; + struct knfsd_fh kfh = { 0 }; + + if (d_really_is_positive(dentry) && S_ISREG(d_inode(dentry)->i_mode)) { + err = fh_compose_shallow(&kfh, fhp->fh_maxsize, + fhp->fh_export, dentry, fhp); + if (err == nfs_ok) + ret = nfsd_file_is_cached(&kfh); + } + return ret; +} + /* * Rename a file * N.B. After this call _both_ ffhp and tfhp need an fh_put @@ -1608,6 +1624,7 @@ nfsd_rename(struct svc_rqst *rqstp, struct svc_fh *ffhp, char *fname, int flen, struct inode *fdir, *tdir; __be32 err; int host_err; + bool has_cached = false; err = fh_verify(rqstp, ffhp, S_IFDIR, NFSD_MAY_REMOVE); if (err) @@ -1626,6 +1643,7 @@ nfsd_rename(struct svc_rqst *rqstp, struct svc_fh *ffhp, char *fname, int flen, if (!flen || isdotent(fname, flen) || !tlen || isdotent(tname, tlen)) goto out; +retry: host_err = fh_want_write(ffhp); if (host_err) { err = nfserrno(host_err); @@ -1665,12 +1683,16 @@ 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, tfhp); - host_err = vfs_rename(fdir, odentry, tdir, ndentry, NULL, 0); - if (!host_err) { - host_err = commit_metadata(tfhp); - if (!host_err) - host_err = commit_metadata(ffhp); + if (nfsd_has_cached_files(ndentry, tfhp)) { + has_cached = true; + goto out_dput_old; + } else { + host_err = vfs_rename(fdir, odentry, tdir, ndentry, NULL, 0); + if (!host_err) { + host_err = commit_metadata(tfhp); + if (!host_err) + host_err = commit_metadata(ffhp); + } } out_dput_new: dput(ndentry); @@ -1683,12 +1705,26 @@ nfsd_rename(struct svc_rqst *rqstp, struct svc_fh *ffhp, char *fname, int flen, * as that would do the wrong thing if the two directories * were the same, so again we do it by hand. */ - fill_post_wcc(ffhp); - fill_post_wcc(tfhp); + if (!has_cached) { + fill_post_wcc(ffhp); + fill_post_wcc(tfhp); + } unlock_rename(tdentry, fdentry); ffhp->fh_locked = tfhp->fh_locked = 0; fh_drop_write(ffhp); + /* + * If the target dentry has cached open files, then we need to try to + * close them prior to doing the rename. Flushing delayed fput + * shouldn't be done with locks held however, so we delay it until this + * point and then reattempt the whole shebang. + */ + if (has_cached) { + has_cached = false; + nfsd_close_cached_files(ndentry, tfhp); + dput(ndentry); + goto retry; + } out: return err; } -- 2.4.3