This is a note to let you know that I've just added the patch titled
NFS: Fix dentry verifier races
to the 5.10-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-5.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit ddf366daf1a93a3249a9e6a4897a0c978fad35cd
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 c837675cd395a..8b963c72dd3b1 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;
}
