From 5e608671dfbfd6a9556c31df65a4f147439eed59 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Thu, 28 Feb 2013 01:50:20 -0500 Subject: [PATCH] 9p: if v9fs_fid_lookup() gets to asking server, it'd better have hashed dentry ... otherwise the path we'd built isn't worth much. Don't accept such fids obtained from paths unless dentry is still alived by the end of the work. Signed-off-by: Al Viro --- fs/9p/fid.c | 20 +++++++++++++++++--- 1 file changed, 17 insertions(+), 3 deletions(-) diff --git a/fs/9p/fid.c b/fs/9p/fid.c index 73ca55042cb0..616abaf1c6cd 100644 --- a/fs/9p/fid.c +++ b/fs/9p/fid.c @@ -41,10 +41,15 @@ * */ +static inline void __add_fid(struct dentry *dentry, struct p9_fid *fid) +{ + hlist_add_head(&fid->dlist, (struct hlist_head *)&dentry->d_fsdata); +} + void v9fs_fid_add(struct dentry *dentry, struct p9_fid *fid) { spin_lock(&dentry->d_lock); - hlist_add_head(&fid->dlist, (struct hlist_head *)&dentry->d_fsdata); + __add_fid(dentry, fid); spin_unlock(&dentry->d_lock); } @@ -198,8 +203,17 @@ static struct p9_fid *v9fs_fid_lookup_with_uid(struct dentry *dentry, } kfree(wnames); fid_out: - if (!IS_ERR(fid)) - v9fs_fid_add(dentry, fid); + if (!IS_ERR(fid)) { + spin_lock(&dentry->d_lock); + if (d_unhashed(dentry)) { + spin_unlock(&dentry->d_lock); + p9_client_clunk(fid); + fid = ERR_PTR(-ENOENT); + } else { + __add_fid(dentry, fid); + spin_unlock(&dentry->d_lock); + } + } err_out: up_read(&v9ses->rename_sem); return fid; -- 2.39.5