[PATCH] fuse: fix inconsistent status between faccess and mkdir

[Fengnan Chang <changfengnan@xxxxxxxx>]

since FUSE caches dentries and attributes with separate timeout, It may
happen that checking the permission returns -ENOENT, but because the
dentries cache has not timed out, creating the file returns -EEXIST.
Fix this by when return ENOENT, mark the entry as stale.

Signed-off-by: Fengnan Chang <changfengnan@xxxxxxxx>
---
 fs/fuse/dir.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c
index 06a18700a845..154dd4578762 100644
--- a/fs/fuse/dir.c
+++ b/fs/fuse/dir.c
@@ -1065,6 +1065,14 @@ static int fuse_do_getattr(struct inode *inode, struct kstat *stat,
 				fuse_fillattr(inode, &outarg.attr, stat);
 		}
 	}
+	if (err == -ENOENT) {
+		struct dentry *entry;
+
+		entry = d_obtain_alias(inode);
+		if (!IS_ERR(entry) && get_node_id(inode) != FUSE_ROOT_ID)
+			fuse_invalidate_entry_cache(entry);
+	}
+
 	return err;
 }

@@ -1226,6 +1234,14 @@ static int fuse_access(struct inode *inode, int mask)
 		fm->fc->no_access = 1;
 		err = 0;
 	}
+	if (err == -ENOENT) {
+		struct dentry *entry;
+
+		entry = d_obtain_alias(inode);
+		if (!IS_ERR(entry) && get_node_id(inode) != FUSE_ROOT_ID)
+			fuse_invalidate_entry_cache(entry);
+	}
+
 	return err;
 }

-- 
2.29.0