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 <jeff.layton@xxxxxxxxxxxxxxx>
---
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
--
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