ASR_BASE
Change-Id: Icf3719cc0afe3eeb3edc7fa80a2eb5199ca9dda1
diff --git a/marvell/linux/fs/afs/dynroot.c b/marvell/linux/fs/afs/dynroot.c
new file mode 100644
index 0000000..d069949
--- /dev/null
+++ b/marvell/linux/fs/afs/dynroot.c
@@ -0,0 +1,308 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* AFS dynamic root handling
+ *
+ * Copyright (C) 2018 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ */
+
+#include <linux/fs.h>
+#include <linux/namei.h>
+#include <linux/dns_resolver.h>
+#include "internal.h"
+
+/*
+ * Probe to see if a cell may exist. This prevents positive dentries from
+ * being created unnecessarily.
+ */
+static int afs_probe_cell_name(struct dentry *dentry)
+{
+ struct afs_cell *cell;
+ struct afs_net *net = afs_d2net(dentry);
+ const char *name = dentry->d_name.name;
+ size_t len = dentry->d_name.len;
+ char *result = NULL;
+ int ret;
+
+ /* Names prefixed with a dot are R/W mounts. */
+ if (name[0] == '.') {
+ if (len == 1)
+ return -EINVAL;
+ name++;
+ len--;
+ }
+
+ cell = afs_lookup_cell_rcu(net, name, len);
+ if (!IS_ERR(cell)) {
+ afs_put_cell(net, cell);
+ return 0;
+ }
+
+ ret = dns_query(net->net, "afsdb", name, len, "srv=1",
+ &result, NULL, false);
+ if (ret == -ENODATA || ret == -ENOKEY || ret == 0)
+ ret = -ENOENT;
+ if (ret > 0 && ret >= sizeof(struct dns_server_list_v1_header)) {
+ struct dns_server_list_v1_header *v1 = (void *)result;
+
+ if (v1->hdr.zero == 0 &&
+ v1->hdr.content == DNS_PAYLOAD_IS_SERVER_LIST &&
+ v1->hdr.version == 1 &&
+ (v1->status != DNS_LOOKUP_GOOD &&
+ v1->status != DNS_LOOKUP_GOOD_WITH_BAD))
+ return -ENOENT;
+
+ }
+
+ kfree(result);
+ return ret;
+}
+
+/*
+ * Try to auto mount the mountpoint with pseudo directory, if the autocell
+ * operation is setted.
+ */
+struct inode *afs_try_auto_mntpt(struct dentry *dentry, struct inode *dir)
+{
+ struct afs_vnode *vnode = AFS_FS_I(dir);
+ struct inode *inode;
+ int ret = -ENOENT;
+
+ _enter("%p{%pd}, {%llx:%llu}",
+ dentry, dentry, vnode->fid.vid, vnode->fid.vnode);
+
+ if (!test_bit(AFS_VNODE_AUTOCELL, &vnode->flags))
+ goto out;
+
+ ret = afs_probe_cell_name(dentry);
+ if (ret < 0)
+ goto out;
+
+ inode = afs_iget_pseudo_dir(dir->i_sb, false);
+ if (IS_ERR(inode)) {
+ ret = PTR_ERR(inode);
+ goto out;
+ }
+
+ _leave("= %p", inode);
+ return inode;
+
+out:
+ _leave("= %d", ret);
+ return ret == -ENOENT ? NULL : ERR_PTR(ret);
+}
+
+/*
+ * Look up @cell in a dynroot directory. This is a substitution for the
+ * local cell name for the net namespace.
+ */
+static struct dentry *afs_lookup_atcell(struct dentry *dentry)
+{
+ struct afs_cell *cell;
+ struct afs_net *net = afs_d2net(dentry);
+ struct dentry *ret;
+ unsigned int seq = 0;
+ char *name;
+ int len;
+
+ if (!net->ws_cell)
+ return ERR_PTR(-ENOENT);
+
+ ret = ERR_PTR(-ENOMEM);
+ name = kmalloc(AFS_MAXCELLNAME + 1, GFP_KERNEL);
+ if (!name)
+ goto out_p;
+
+ rcu_read_lock();
+ do {
+ read_seqbegin_or_lock(&net->cells_lock, &seq);
+ cell = rcu_dereference_raw(net->ws_cell);
+ if (cell) {
+ len = cell->name_len;
+ memcpy(name, cell->name, len + 1);
+ }
+ } while (need_seqretry(&net->cells_lock, seq));
+ done_seqretry(&net->cells_lock, seq);
+ rcu_read_unlock();
+
+ ret = ERR_PTR(-ENOENT);
+ if (!cell)
+ goto out_n;
+
+ ret = lookup_one_len(name, dentry->d_parent, len);
+
+ /* We don't want to d_add() the @cell dentry here as we don't want to
+ * the cached dentry to hide changes to the local cell name.
+ */
+
+out_n:
+ kfree(name);
+out_p:
+ return ret;
+}
+
+/*
+ * Look up an entry in a dynroot directory.
+ */
+static struct dentry *afs_dynroot_lookup(struct inode *dir, struct dentry *dentry,
+ unsigned int flags)
+{
+ _enter("%pd", dentry);
+
+ ASSERTCMP(d_inode(dentry), ==, NULL);
+
+ if (flags & LOOKUP_CREATE)
+ return ERR_PTR(-EOPNOTSUPP);
+
+ if (dentry->d_name.len >= AFSNAMEMAX) {
+ _leave(" = -ENAMETOOLONG");
+ return ERR_PTR(-ENAMETOOLONG);
+ }
+
+ if (dentry->d_name.len == 5 &&
+ memcmp(dentry->d_name.name, "@cell", 5) == 0)
+ return afs_lookup_atcell(dentry);
+
+ return d_splice_alias(afs_try_auto_mntpt(dentry, dir), dentry);
+}
+
+const struct inode_operations afs_dynroot_inode_operations = {
+ .lookup = afs_dynroot_lookup,
+};
+
+/*
+ * Dirs in the dynamic root don't need revalidation.
+ */
+static int afs_dynroot_d_revalidate(struct dentry *dentry, unsigned int flags)
+{
+ return 1;
+}
+
+const struct dentry_operations afs_dynroot_dentry_operations = {
+ .d_revalidate = afs_dynroot_d_revalidate,
+ .d_delete = always_delete_dentry,
+ .d_release = afs_d_release,
+ .d_automount = afs_d_automount,
+};
+
+/*
+ * Create a manually added cell mount directory.
+ * - The caller must hold net->proc_cells_lock
+ */
+int afs_dynroot_mkdir(struct afs_net *net, struct afs_cell *cell)
+{
+ struct super_block *sb = net->dynroot_sb;
+ struct dentry *root, *subdir;
+ int ret;
+
+ if (!sb || atomic_read(&sb->s_active) == 0)
+ return 0;
+
+ /* Let the ->lookup op do the creation */
+ root = sb->s_root;
+ inode_lock(root->d_inode);
+ subdir = lookup_one_len(cell->name, root, cell->name_len);
+ if (IS_ERR(subdir)) {
+ ret = PTR_ERR(subdir);
+ goto unlock;
+ }
+
+ /* Note that we're retaining an extra ref on the dentry */
+ subdir->d_fsdata = (void *)1UL;
+ ret = 0;
+unlock:
+ inode_unlock(root->d_inode);
+ return ret;
+}
+
+/*
+ * Remove a manually added cell mount directory.
+ * - The caller must hold net->proc_cells_lock
+ */
+void afs_dynroot_rmdir(struct afs_net *net, struct afs_cell *cell)
+{
+ struct super_block *sb = net->dynroot_sb;
+ struct dentry *root, *subdir;
+
+ if (!sb || atomic_read(&sb->s_active) == 0)
+ return;
+
+ root = sb->s_root;
+ inode_lock(root->d_inode);
+
+ /* Don't want to trigger a lookup call, which will re-add the cell */
+ subdir = try_lookup_one_len(cell->name, root, cell->name_len);
+ if (IS_ERR_OR_NULL(subdir)) {
+ _debug("lookup %ld", PTR_ERR(subdir));
+ goto no_dentry;
+ }
+
+ _debug("rmdir %pd %u", subdir, d_count(subdir));
+
+ if (subdir->d_fsdata) {
+ _debug("unpin %u", d_count(subdir));
+ subdir->d_fsdata = NULL;
+ dput(subdir);
+ }
+ dput(subdir);
+no_dentry:
+ inode_unlock(root->d_inode);
+ _leave("");
+}
+
+/*
+ * Populate a newly created dynamic root with cell names.
+ */
+int afs_dynroot_populate(struct super_block *sb)
+{
+ struct afs_cell *cell;
+ struct afs_net *net = afs_sb2net(sb);
+ int ret;
+
+ mutex_lock(&net->proc_cells_lock);
+
+ net->dynroot_sb = sb;
+ hlist_for_each_entry(cell, &net->proc_cells, proc_link) {
+ ret = afs_dynroot_mkdir(net, cell);
+ if (ret < 0)
+ goto error;
+ }
+
+ ret = 0;
+out:
+ mutex_unlock(&net->proc_cells_lock);
+ return ret;
+
+error:
+ net->dynroot_sb = NULL;
+ goto out;
+}
+
+/*
+ * When a dynamic root that's in the process of being destroyed, depopulate it
+ * of pinned directories.
+ */
+void afs_dynroot_depopulate(struct super_block *sb)
+{
+ struct afs_net *net = afs_sb2net(sb);
+ struct dentry *root = sb->s_root, *subdir, *tmp;
+
+ /* Prevent more subdirs from being created */
+ mutex_lock(&net->proc_cells_lock);
+ if (net->dynroot_sb == sb)
+ net->dynroot_sb = NULL;
+ mutex_unlock(&net->proc_cells_lock);
+
+ if (root) {
+ inode_lock(root->d_inode);
+
+ /* Remove all the pins for dirs created for manually added cells */
+ list_for_each_entry_safe(subdir, tmp, &root->d_subdirs, d_child) {
+ if (subdir->d_fsdata) {
+ subdir->d_fsdata = NULL;
+ dput(subdir);
+ }
+ }
+
+ inode_unlock(root->d_inode);
+ }
+}