From 2e2e88ea8c3bd9e1bd6e42faf047a4ac3fbb3b2f Mon Sep 17 00:00:00 2001 From: Nick Piggin Date: Wed, 18 Aug 2010 04:37:30 +1000 Subject: [PATCH] fs: fix do_lookup false negative fs: fix do_lookup false negative In do_lookup, if we initially find no dentry, we take the directory i_mutex and re-check the lookup. If we find a dentry there, then we revalidate it if needed. However if that revalidate asks for the dentry to be invalidated, we return -ENOENT from do_lookup. What should happen instead is an attempt to allocate and lookup a new dentry. This is probably not noticed because it is rare. It is only reached if a concurrent create races in first (in which case, the dentry probably won't be invalidated anyway), or if the racy __d_lookup has failed due to a false-negative (which is very rare). Fix this by removing code and have it use the normal reval path. Signed-off-by: Nick Piggin Signed-off-by: Al Viro --- fs/namei.c | 10 ++-------- 1 file changed, 2 insertions(+), 8 deletions(-) diff --git a/fs/namei.c b/fs/namei.c index 17ea76bf2fbe..c2742b7dec59 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -709,6 +709,7 @@ static int do_lookup(struct nameidata *nd, struct qstr *name, dentry = __d_lookup(nd->path.dentry, name); if (!dentry) goto need_lookup; +found: if (dentry->d_op && dentry->d_op->d_revalidate) goto need_revalidate; done: @@ -766,14 +767,7 @@ static int do_lookup(struct nameidata *nd, struct qstr *name, * we waited on the semaphore. Need to revalidate. */ mutex_unlock(&dir->i_mutex); - if (dentry->d_op && dentry->d_op->d_revalidate) { - dentry = do_revalidate(dentry, nd); - if (!dentry) - dentry = ERR_PTR(-ENOENT); - } - if (IS_ERR(dentry)) - goto fail; - goto done; + goto found; need_revalidate: dentry = do_revalidate(dentry, nd); -- GitLab