[PATCH] fuse: fix dereferencing dentry parent
There's no locking for ->d_revalidate, so fuse_dentry_revalidate() should use
dget_parent() instead of simply dereferencing ->d_parent.
Due to topology changes in the directory tree the parent could become negative
or be destroyed while being used. There hasn't been any reports about this
yet.
Signed-off-by: Miklos Szeredi <miklos@szeredi.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c
index 9d0ef5e1..cfc8f81 100644
--- a/fs/fuse/dir.c
+++ b/fs/fuse/dir.c
@@ -138,6 +138,7 @@
struct fuse_entry_out outarg;
struct fuse_conn *fc;
struct fuse_req *req;
+ struct dentry *parent;
/* Doesn't hurt to "reset" the validity timeout */
fuse_invalidate_entry_cache(entry);
@@ -151,8 +152,10 @@
if (IS_ERR(req))
return 0;
- fuse_lookup_init(req, entry->d_parent->d_inode, entry, &outarg);
+ parent = dget_parent(entry);
+ fuse_lookup_init(req, parent->d_inode, entry, &outarg);
request_send(fc, req);
+ dput(parent);
err = req->out.h.error;
/* Zero nodeid is same as -ENOENT */
if (!err && !outarg.nodeid)