nfs: when attempting to open a directory, fall back on normal lookup (try #5)
commit d953126 changed how nfs_atomic_lookup handles an -EISDIR return
from an OPEN call. Prior to that patch, that caused the client to fall
back to doing a normal lookup. When that patch went in, the code began
returning that error to userspace. The d_revalidate codepath however
never had the corresponding change, so it was still possible to end up
with a NULL ctx->state pointer after that.
That patch caused a regression. When we attempt to open a directory that
does not have a cached dentry, that open now errors out with EISDIR. If
you attempt the same open with a cached dentry, it will succeed.
Fix this by reverting the change in nfs_atomic_lookup and allowing
attempts to open directories to fall back to a normal lookup
Also, add a NFSv4-specific f_ops->open routine that just returns
-ENOTDIR. This should never be called if things are working properly,
but if it ever is, then the dprintk may help in debugging.
To facilitate this, a new file_operations field is also added to the
nfs_rpc_ops struct.
Cc: stable@kernel.org
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/fs/nfs/file.c b/fs/nfs/file.c
index 0a1f831..6d93e07 100644
--- a/fs/nfs/file.c
+++ b/fs/nfs/file.c
@@ -886,3 +886,35 @@
file->f_path.dentry->d_name.name, arg);
return -EINVAL;
}
+
+#ifdef CONFIG_NFS_V4
+static int
+nfs4_file_open(struct inode *inode, struct file *filp)
+{
+ /*
+ * NFSv4 opens are handled in d_lookup and d_revalidate. If we get to
+ * this point, then something is very wrong
+ */
+ dprintk("NFS: %s called! inode=%p filp=%p\n", __func__, inode, filp);
+ return -ENOTDIR;
+}
+
+const struct file_operations nfs4_file_operations = {
+ .llseek = nfs_file_llseek,
+ .read = do_sync_read,
+ .write = do_sync_write,
+ .aio_read = nfs_file_read,
+ .aio_write = nfs_file_write,
+ .mmap = nfs_file_mmap,
+ .open = nfs4_file_open,
+ .flush = nfs_file_flush,
+ .release = nfs_file_release,
+ .fsync = nfs_file_fsync,
+ .lock = nfs_lock,
+ .flock = nfs_flock,
+ .splice_read = nfs_file_splice_read,
+ .splice_write = nfs_file_splice_write,
+ .check_flags = nfs_check_flags,
+ .setlease = nfs_setlease,
+};
+#endif /* CONFIG_NFS_V4 */
