NFS: Ensure we always hold the BKL when dereferencing inode->i_flock
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/fs/nfs/delegation.c b/fs/nfs/delegation.c
index d4f669f..af05b91 100644
--- a/fs/nfs/delegation.c
+++ b/fs/nfs/delegation.c
@@ -70,15 +70,24 @@
struct file_lock *fl;
int status = 0;
+ if (inode->i_flock == NULL)
+ goto out;
+
+ /* Protect inode->i_flock using the BKL */
+ lock_kernel();
for (fl = inode->i_flock; fl != NULL; fl = fl->fl_next) {
if (!(fl->fl_flags & (FL_POSIX|FL_FLOCK)))
continue;
if (nfs_file_open_context(fl->fl_file) != ctx)
continue;
+ unlock_kernel();
status = nfs4_lock_delegation_recall(state, fl);
if (status < 0)
- break;
+ goto out;
+ lock_kernel();
}
+ unlock_kernel();
+out:
return status;
}
@@ -256,7 +265,10 @@
struct nfs_inode *nfsi = NFS_I(inode);
nfs_msync_inode(inode);
- /* Guard against new delegated open calls */
+ /*
+ * Guard against new delegated open/lock/unlock calls and against
+ * state recovery
+ */
down_write(&nfsi->rwsem);
nfs_delegation_claim_opens(inode, &delegation->stateid);
up_write(&nfsi->rwsem);