nfsd4: fix leak of inode reference on delegation failure

This fixes a regression from 68a3396178e6688ad7367202cdf0af8ed03c8727
"nfsd4: shut down more of delegation earlier".

After that commit, nfs4_set_delegation() failures result in
nfs4_put_delegation being called, but nfs4_put_delegation doesn't free
the nfs4_file that has already been set by alloc_init_deleg().

This can result in an oops on later unmounting the exported filesystem.

Note also delaying the fi_had_conflict check we're able to return a
better error (hence give 4.1 clients a better idea why the delegation
failed; though note CONFLICT isn't an exact match here, as that's
supposed to indicate a current conflict, but all we know here is that
there was one recently).

Reported-by: Toralf Förster <toralf.foerster@gmx.de>
Tested-by: Toralf Förster <toralf.foerster@gmx.de>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

1 files changed, 20 insertions, 11 deletions

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index eb9cf818002a..0874998a49cd 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -368,11 +368,8 @@ static struct nfs4_delegation *
 alloc_init_deleg(struct nfs4_client *clp, struct nfs4_ol_stateid *stp, struct svc_fh *current_fh)
 {
         struct nfs4_delegation *dp;
-        struct nfs4_file *fp = stp->st_file;
 
         dprintk("NFSD alloc_init_deleg\n");
-        if (fp->fi_had_conflict)
-                return NULL;
         if (num_delegations > max_delegations)
                 return NULL;
         dp = delegstateid(nfs4_alloc_stid(clp, deleg_slab));
@@ -389,8 +386,7 @@ alloc_init_deleg(struct nfs4_client *clp, struct nfs4_ol_stateid *stp, struct sv
         INIT_LIST_HEAD(&dp->dl_perfile);
         INIT_LIST_HEAD(&dp->dl_perclnt);
         INIT_LIST_HEAD(&dp->dl_recall_lru);
-        get_nfs4_file(fp);
-        dp->dl_file = fp;
+        dp->dl_file = NULL;
         dp->dl_type = NFS4_OPEN_DELEGATE_READ;
         fh_copy_shallow(&dp->dl_fh, &current_fh->fh_handle);
         dp->dl_time = 0;
@@ -3044,22 +3040,35 @@ static int nfs4_setlease(struct nfs4_delegation *dp)
         return 0;
 }
 
-static int nfs4_set_delegation(struct nfs4_delegation *dp)
+static int nfs4_set_delegation(struct nfs4_delegation *dp, struct nfs4_file *fp)
 {
-        struct nfs4_file *fp = dp->dl_file;
+        int status;
 
-        if (!fp->fi_lease)
-                return nfs4_setlease(dp);
+        if (fp->fi_had_conflict)
+                return -EAGAIN;
+        get_nfs4_file(fp);
+        dp->dl_file = fp;
+        if (!fp->fi_lease) {
+                status = nfs4_setlease(dp);
+                if (status)
+                        goto out_free;
+                return 0;
+        }
         spin_lock(&recall_lock);
         if (fp->fi_had_conflict) {
                 spin_unlock(&recall_lock);
-                return -EAGAIN;
+                status = -EAGAIN;
+                goto out_free;
         }
         atomic_inc(&fp->fi_delegees);
         list_add(&dp->dl_perfile, &fp->fi_delegations);
         spin_unlock(&recall_lock);
         list_add(&dp->dl_perclnt, &dp->dl_stid.sc_client->cl_delegations);
         return 0;
+out_free:
+        put_nfs4_file(fp);
+        dp->dl_file = fp;
+        return status;
 }
 
 static void nfsd4_open_deleg_none_ext(struct nfsd4_open *open, int status)
@@ -3134,7 +3143,7 @@ nfs4_open_delegation(struct net *net, struct svc_fh *fh,
         dp = alloc_init_deleg(oo->oo_owner.so_client, stp, fh);
         if (dp == NULL)
                 goto out_no_deleg;
-        status = nfs4_set_delegation(dp);
+        status = nfs4_set_delegation(dp, stp->st_file);
         if (status)
                 goto out_free;