nfsd: racy access to ->d_name in nsfd4_encode_path()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index c2a4701..d9454fe 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -1816,10 +1816,7 @@
static __be32 nfsd4_encode_path(const struct path *root,
const struct path *path, __be32 **pp, int *buflen)
{
- struct path cur = {
- .mnt = path->mnt,
- .dentry = path->dentry,
- };
+ struct path cur = *path;
__be32 *p = *pp;
struct dentry **components = NULL;
unsigned int ncomponents = 0;
@@ -1859,14 +1856,19 @@
while (ncomponents) {
struct dentry *dentry = components[ncomponents - 1];
- unsigned int len = dentry->d_name.len;
+ unsigned int len;
+ spin_lock(&dentry->d_lock);
+ len = dentry->d_name.len;
*buflen -= 4 + (XDR_QUADLEN(len) << 2);
- if (*buflen < 0)
+ if (*buflen < 0) {
+ spin_unlock(&dentry->d_lock);
goto out_free;
+ }
WRITE32(len);
WRITEMEM(dentry->d_name.name, len);
dprintk("/%s", dentry->d_name.name);
+ spin_unlock(&dentry->d_lock);
dput(dentry);
ncomponents--;
}