1 files changed, 33 insertions, 8 deletions

diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index aaf7bd0cbae2..19d93d0cd400 100644
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -424,12 +424,17 @@ static int xdr_decode(nfs_readdir_descriptor_t *desc,
 static
 int nfs_same_file(struct dentry *dentry, struct nfs_entry *entry)
 {
+	struct inode *inode;
 	struct nfs_inode *nfsi;
 
 	if (d_really_is_negative(dentry))
 		return 0;
 
-	nfsi = NFS_I(d_inode(dentry));
+	inode = d_inode(dentry);
+	if (is_bad_inode(inode) || NFS_STALE(inode))
+		return 0;
+
+	nfsi = NFS_I(inode);
 	if (entry->fattr->fileid == nfsi->fileid)
 		return 1;
 	if (nfs_compare_fh(entry->fh, &nfsi->fh) == 0)
@@ -1363,7 +1368,6 @@ EXPORT_SYMBOL_GPL(nfs_dentry_operations);
 struct dentry *nfs_lookup(struct inode *dir, struct dentry * dentry, unsigned int flags)
 {
 	struct dentry *res;
-	struct dentry *parent;
 	struct inode *inode = NULL;
 	struct nfs_fh *fhandle = NULL;
 	struct nfs_fattr *fattr = NULL;
@@ -1393,7 +1397,6 @@ struct dentry *nfs_lookup(struct inode *dir, struct dentry * dentry, unsigned in
 	if (IS_ERR(label))
 		goto out;
 
-	parent = dentry->d_parent;
 	/* Protect against concurrent sillydeletes */
 	trace_nfs_lookup_enter(dir, dentry, flags);
 	error = NFS_PROTO(dir)->lookup(dir, &dentry->d_name, fhandle, fattr, label);
@@ -1482,11 +1485,13 @@ int nfs_atomic_open(struct inode *dir, struct dentry *dentry,
 		    struct file *file, unsigned open_flags,
 		    umode_t mode, int *opened)
 {
+	DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
 	struct nfs_open_context *ctx;
 	struct dentry *res;
 	struct iattr attr = { .ia_valid = ATTR_OPEN };
 	struct inode *inode;
 	unsigned int lookup_flags = 0;
+	bool switched = false;
 	int err;
 
 	/* Expect a negative dentry */
@@ -1501,7 +1506,7 @@ int nfs_atomic_open(struct inode *dir, struct dentry *dentry,
 
 	/* NFS only supports OPEN on regular files */
 	if ((open_flags & O_DIRECTORY)) {
-		if (!d_unhashed(dentry)) {
+		if (!d_in_lookup(dentry)) {
 			/*
 			 * Hashed negative dentry with O_DIRECTORY: dentry was
 			 * revalidated and is fine, no need to perform lookup
@@ -1525,6 +1530,17 @@ int nfs_atomic_open(struct inode *dir, struct dentry *dentry,
 		attr.ia_size = 0;
 	}
 
+	if (!(open_flags & O_CREAT) && !d_in_lookup(dentry)) {
+		d_drop(dentry);
+		switched = true;
+		dentry = d_alloc_parallel(dentry->d_parent,
+					  &dentry->d_name, &wq);
+		if (IS_ERR(dentry))
+			return PTR_ERR(dentry);
+		if (unlikely(!d_in_lookup(dentry)))
+			return finish_no_open(file, dentry);
+	}
+
 	ctx = create_nfs_open_context(dentry, open_flags);
 	err = PTR_ERR(ctx);
 	if (IS_ERR(ctx))
@@ -1536,9 +1552,9 @@ int nfs_atomic_open(struct inode *dir, struct dentry *dentry,
 		err = PTR_ERR(inode);
 		trace_nfs_atomic_open_exit(dir, ctx, open_flags, err);
 		put_nfs_open_context(ctx);
+		d_drop(dentry);
 		switch (err) {
 		case -ENOENT:
-			d_drop(dentry);
 			d_add(dentry, NULL);
 			nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
 			break;
@@ -1560,14 +1576,23 @@ int nfs_atomic_open(struct inode *dir, struct dentry *dentry,
 	trace_nfs_atomic_open_exit(dir, ctx, open_flags, err);
 	put_nfs_open_context(ctx);
 out:
+	if (unlikely(switched)) {
+		d_lookup_done(dentry);
+		dput(dentry);
+	}
 	return err;
 
 no_open:
 	res = nfs_lookup(dir, dentry, lookup_flags);
-	err = PTR_ERR(res);
+	if (switched) {
+		d_lookup_done(dentry);
+		if (!res)
+			res = dentry;
+		else
+			dput(dentry);
+	}
 	if (IS_ERR(res))
-		goto out;
-
+		return PTR_ERR(res);
 	return finish_no_open(file, res);
 }
 EXPORT_SYMBOL_GPL(nfs_atomic_open);