From 8ac076ce719321901ebd2df30fba690671adbd7e Mon Sep 17 00:00:00 2001 From: Trond Myklebust Date: Wed, 29 Sep 2021 08:12:53 -0400 Subject: [PATCH] NFS: Fix dentry verifier races [ Upstream commit cec08f452a687fce9dfdf47946d00a1d12a8bec5 ] If the directory changed while we were revalidating the dentry, then don't update the dentry verifier. There is no value in setting the verifier to an older value, and we could end up overwriting a more up to date verifier from a parallel revalidation. Fixes: efeda80da38d ("NFSv4: Fix revalidation of dentries with delegations") Signed-off-by: Trond Myklebust Tested-by: Benjamin Coddington Reviewed-by: Benjamin Coddington Signed-off-by: Sasha Levin --- fs/nfs/dir.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c index c837675cd395..8b963c72dd3b 100644 --- a/fs/nfs/dir.c +++ b/fs/nfs/dir.c @@ -1061,13 +1061,12 @@ static bool nfs_verifier_is_delegated(struct dentry *dentry) static void nfs_set_verifier_locked(struct dentry *dentry, unsigned long verf) { struct inode *inode = d_inode(dentry); + struct inode *dir = d_inode(dentry->d_parent); - if (!nfs_verifier_is_delegated(dentry) && - !nfs_verify_change_attribute(d_inode(dentry->d_parent), verf)) - goto out; + if (!nfs_verify_change_attribute(dir, verf)) + return; if (inode && NFS_PROTO(inode)->have_delegation(inode, FMODE_READ)) nfs_set_verifier_delegated(&verf); -out: dentry->d_time = verf; }