android/android_kernel_xiaomi_sm8450
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NFS: Fix dentry verifier races

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[ 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: efeda80da3 ("NFSv4: Fix revalidation of dentries with delegations")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Tested-by: Benjamin Coddington <bcodding@redhat.com>
Reviewed-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Trond Myklebust 2021-09-29 08:12:53 -04:00 committed by Greg Kroah-Hartman
parent 9d438dbf73
commit 8ac076ce71
1 changed files with 3 additions and 4 deletions
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7
fs/nfs/dir.c
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@ -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;
}