This is a note to let you know that I've just added the patch titled NFS: Fix dentry verifier races to the 5.15-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: nfs-fix-dentry-verifier-races.patch and it can be found in the queue-5.15 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 38e9fb9d2c216bbc951463089a6cbc5095f1e8ff Author: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx> Date: Wed Sep 29 08:12:53 2021 -0400 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 <trond.myklebust@xxxxxxxxxxxxxxx> Tested-by: Benjamin Coddington <bcodding@xxxxxxxxxx> Reviewed-by: Benjamin Coddington <bcodding@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c index 085b8ecdc17d9..5b68c44848caf 100644 --- a/fs/nfs/dir.c +++ b/fs/nfs/dir.c @@ -1269,13 +1269,12 @@ 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; }