The documenting comment for struct nf_file states:
/*
* A representation of a file that has been opened by knfsd. These are hashed
* in the hashtable by inode pointer value. Note that this object doesn't
* hold a reference to the inode by itself, so the nf_inode pointer should
* never be dereferenced, only used for comparison.
*/
However, nfsd_file_mark_find_or_create() does dereference the pointer stored
in this field.
Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
---
fs/nfsd/filecache.c | 3 +++
fs/nfsd/filecache.h | 4 +---
2 files changed, 4 insertions(+), 3 deletions(-)
Hi Jeff-
I'm still testing this one, but I'm wondering what you think of it.
I did hit a KASAN splat that might be related, but it's not 100%
reproducible.
diff --git a/fs/nfsd/filecache.c b/fs/nfsd/filecache.c
index 9cb2d590c036..7b43bb427a53 100644
--- a/fs/nfsd/filecache.c
+++ b/fs/nfsd/filecache.c
@@ -180,6 +180,7 @@ nfsd_file_alloc(struct inode *inode, unsigned int may, unsigned int hashval,
nf->nf_cred = get_current_cred();
nf->nf_net = net;
nf->nf_flags = 0;
+ ihold(inode);
nf->nf_inode = inode;
nf->nf_hashval = hashval;
refcount_set(&nf->nf_ref, 1);
@@ -210,6 +211,7 @@ nfsd_file_free(struct nfsd_file *nf)
fput(nf->nf_file);
flush = true;
}
+ iput(nf->nf_inode);
call_rcu(&nf->nf_rcu, nfsd_file_slab_free);
return flush;
}
@@ -940,6 +942,7 @@ nfsd_do_file_acquire(struct svc_rqst *rqstp, struct svc_fh *fhp,
if (nf == NULL)
goto open_file;
spin_unlock(&nfsd_file_hashtbl[hashval].nfb_lock);
+ iput(new->nf_inode);
nfsd_file_slab_free(&new->nf_rcu);
wait_for_construction:
diff --git a/fs/nfsd/filecache.h b/fs/nfsd/filecache.h
index 1da0c79a5580..01fbf6e88cce 100644
--- a/fs/nfsd/filecache.h
+++ b/fs/nfsd/filecache.h
@@ -24,9 +24,7 @@ struct nfsd_file_mark {
/*
* A representation of a file that has been opened by knfsd. These are hashed
- * in the hashtable by inode pointer value. Note that this object doesn't
- * hold a reference to the inode by itself, so the nf_inode pointer should
- * never be dereferenced, only used for comparison.
+ * in the hashtable by inode pointer value.
*/
struct nfsd_file {
struct hlist_node nf_node;
