[Feature]add MT2731_MP2_MR2_SVN388 baseline version
Change-Id: Ief04314834b31e27effab435d3ca8ba33b499059
diff --git a/src/kernel/linux/v4.14/fs/kernfs/mount.c b/src/kernel/linux/v4.14/fs/kernfs/mount.c
new file mode 100644
index 0000000..5019058
--- /dev/null
+++ b/src/kernel/linux/v4.14/fs/kernfs/mount.c
@@ -0,0 +1,420 @@
+/*
+ * fs/kernfs/mount.c - kernfs mount implementation
+ *
+ * Copyright (c) 2001-3 Patrick Mochel
+ * Copyright (c) 2007 SUSE Linux Products GmbH
+ * Copyright (c) 2007, 2013 Tejun Heo <tj@kernel.org>
+ *
+ * This file is released under the GPLv2.
+ */
+
+#include <linux/fs.h>
+#include <linux/mount.h>
+#include <linux/init.h>
+#include <linux/magic.h>
+#include <linux/slab.h>
+#include <linux/pagemap.h>
+#include <linux/namei.h>
+#include <linux/seq_file.h>
+#include <linux/exportfs.h>
+
+#include "kernfs-internal.h"
+
+struct kmem_cache *kernfs_node_cache;
+
+static int kernfs_sop_remount_fs(struct super_block *sb, int *flags, char *data)
+{
+ struct kernfs_root *root = kernfs_info(sb)->root;
+ struct kernfs_syscall_ops *scops = root->syscall_ops;
+
+ if (scops && scops->remount_fs)
+ return scops->remount_fs(root, flags, data);
+ return 0;
+}
+
+static int kernfs_sop_show_options(struct seq_file *sf, struct dentry *dentry)
+{
+ struct kernfs_root *root = kernfs_root(kernfs_dentry_node(dentry));
+ struct kernfs_syscall_ops *scops = root->syscall_ops;
+
+ if (scops && scops->show_options)
+ return scops->show_options(sf, root);
+ return 0;
+}
+
+static int kernfs_sop_show_path(struct seq_file *sf, struct dentry *dentry)
+{
+ struct kernfs_node *node = kernfs_dentry_node(dentry);
+ struct kernfs_root *root = kernfs_root(node);
+ struct kernfs_syscall_ops *scops = root->syscall_ops;
+
+ if (scops && scops->show_path)
+ return scops->show_path(sf, node, root);
+
+ seq_dentry(sf, dentry, " \t\n\\");
+ return 0;
+}
+
+const struct super_operations kernfs_sops = {
+ .statfs = simple_statfs,
+ .drop_inode = generic_delete_inode,
+ .evict_inode = kernfs_evict_inode,
+
+ .remount_fs = kernfs_sop_remount_fs,
+ .show_options = kernfs_sop_show_options,
+ .show_path = kernfs_sop_show_path,
+};
+
+/*
+ * Similar to kernfs_fh_get_inode, this one gets kernfs node from inode
+ * number and generation
+ */
+struct kernfs_node *kernfs_get_node_by_id(struct kernfs_root *root,
+ const union kernfs_node_id *id)
+{
+ struct kernfs_node *kn;
+
+ kn = kernfs_find_and_get_node_by_ino(root, id->ino);
+ if (!kn)
+ return NULL;
+ if (kn->id.generation != id->generation) {
+ kernfs_put(kn);
+ return NULL;
+ }
+ return kn;
+}
+
+static struct inode *kernfs_fh_get_inode(struct super_block *sb,
+ u64 ino, u32 generation)
+{
+ struct kernfs_super_info *info = kernfs_info(sb);
+ struct inode *inode;
+ struct kernfs_node *kn;
+
+ if (ino == 0)
+ return ERR_PTR(-ESTALE);
+
+ kn = kernfs_find_and_get_node_by_ino(info->root, ino);
+ if (!kn)
+ return ERR_PTR(-ESTALE);
+ inode = kernfs_get_inode(sb, kn);
+ kernfs_put(kn);
+ if (!inode)
+ return ERR_PTR(-ESTALE);
+
+ if (generation && inode->i_generation != generation) {
+ /* we didn't find the right inode.. */
+ iput(inode);
+ return ERR_PTR(-ESTALE);
+ }
+ return inode;
+}
+
+static struct dentry *kernfs_fh_to_dentry(struct super_block *sb, struct fid *fid,
+ int fh_len, int fh_type)
+{
+ return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
+ kernfs_fh_get_inode);
+}
+
+static struct dentry *kernfs_fh_to_parent(struct super_block *sb, struct fid *fid,
+ int fh_len, int fh_type)
+{
+ return generic_fh_to_parent(sb, fid, fh_len, fh_type,
+ kernfs_fh_get_inode);
+}
+
+static struct dentry *kernfs_get_parent_dentry(struct dentry *child)
+{
+ struct kernfs_node *kn = kernfs_dentry_node(child);
+
+ return d_obtain_alias(kernfs_get_inode(child->d_sb, kn->parent));
+}
+
+static const struct export_operations kernfs_export_ops = {
+ .fh_to_dentry = kernfs_fh_to_dentry,
+ .fh_to_parent = kernfs_fh_to_parent,
+ .get_parent = kernfs_get_parent_dentry,
+};
+
+/**
+ * kernfs_root_from_sb - determine kernfs_root associated with a super_block
+ * @sb: the super_block in question
+ *
+ * Return the kernfs_root associated with @sb. If @sb is not a kernfs one,
+ * %NULL is returned.
+ */
+struct kernfs_root *kernfs_root_from_sb(struct super_block *sb)
+{
+ if (sb->s_op == &kernfs_sops)
+ return kernfs_info(sb)->root;
+ return NULL;
+}
+
+/*
+ * find the next ancestor in the path down to @child, where @parent was the
+ * ancestor whose descendant we want to find.
+ *
+ * Say the path is /a/b/c/d. @child is d, @parent is NULL. We return the root
+ * node. If @parent is b, then we return the node for c.
+ * Passing in d as @parent is not ok.
+ */
+static struct kernfs_node *find_next_ancestor(struct kernfs_node *child,
+ struct kernfs_node *parent)
+{
+ if (child == parent) {
+ pr_crit_once("BUG in find_next_ancestor: called with parent == child");
+ return NULL;
+ }
+
+ while (child->parent != parent) {
+ if (!child->parent)
+ return NULL;
+ child = child->parent;
+ }
+
+ return child;
+}
+
+/**
+ * kernfs_node_dentry - get a dentry for the given kernfs_node
+ * @kn: kernfs_node for which a dentry is needed
+ * @sb: the kernfs super_block
+ */
+struct dentry *kernfs_node_dentry(struct kernfs_node *kn,
+ struct super_block *sb)
+{
+ struct dentry *dentry;
+ struct kernfs_node *knparent = NULL;
+
+ BUG_ON(sb->s_op != &kernfs_sops);
+
+ dentry = dget(sb->s_root);
+
+ /* Check if this is the root kernfs_node */
+ if (!kn->parent)
+ return dentry;
+
+ knparent = find_next_ancestor(kn, NULL);
+ if (WARN_ON(!knparent)) {
+ dput(dentry);
+ return ERR_PTR(-EINVAL);
+ }
+
+ do {
+ struct dentry *dtmp;
+ struct kernfs_node *kntmp;
+
+ if (kn == knparent)
+ return dentry;
+ kntmp = find_next_ancestor(kn, knparent);
+ if (WARN_ON(!kntmp)) {
+ dput(dentry);
+ return ERR_PTR(-EINVAL);
+ }
+ dtmp = lookup_one_len_unlocked(kntmp->name, dentry,
+ strlen(kntmp->name));
+ dput(dentry);
+ if (IS_ERR(dtmp))
+ return dtmp;
+ knparent = kntmp;
+ dentry = dtmp;
+ } while (true);
+}
+
+static int kernfs_fill_super(struct super_block *sb, unsigned long magic)
+{
+ struct kernfs_super_info *info = kernfs_info(sb);
+ struct inode *inode;
+ struct dentry *root;
+
+ info->sb = sb;
+ /* Userspace would break if executables or devices appear on sysfs */
+ sb->s_iflags |= SB_I_NOEXEC | SB_I_NODEV;
+ sb->s_blocksize = PAGE_SIZE;
+ sb->s_blocksize_bits = PAGE_SHIFT;
+ sb->s_magic = magic;
+ sb->s_op = &kernfs_sops;
+ sb->s_xattr = kernfs_xattr_handlers;
+ if (info->root->flags & KERNFS_ROOT_SUPPORT_EXPORTOP)
+ sb->s_export_op = &kernfs_export_ops;
+ sb->s_time_gran = 1;
+
+ /* get root inode, initialize and unlock it */
+ mutex_lock(&kernfs_mutex);
+ inode = kernfs_get_inode(sb, info->root->kn);
+ mutex_unlock(&kernfs_mutex);
+ if (!inode) {
+ pr_debug("kernfs: could not get root inode\n");
+ return -ENOMEM;
+ }
+
+ /* instantiate and link root dentry */
+ root = d_make_root(inode);
+ if (!root) {
+ pr_debug("%s: could not get root dentry!\n", __func__);
+ return -ENOMEM;
+ }
+ sb->s_root = root;
+ sb->s_d_op = &kernfs_dops;
+ return 0;
+}
+
+static int kernfs_test_super(struct super_block *sb, void *data)
+{
+ struct kernfs_super_info *sb_info = kernfs_info(sb);
+ struct kernfs_super_info *info = data;
+
+ return sb_info->root == info->root && sb_info->ns == info->ns;
+}
+
+static int kernfs_set_super(struct super_block *sb, void *data)
+{
+ int error;
+ error = set_anon_super(sb, data);
+ if (!error)
+ sb->s_fs_info = data;
+ return error;
+}
+
+/**
+ * kernfs_super_ns - determine the namespace tag of a kernfs super_block
+ * @sb: super_block of interest
+ *
+ * Return the namespace tag associated with kernfs super_block @sb.
+ */
+const void *kernfs_super_ns(struct super_block *sb)
+{
+ struct kernfs_super_info *info = kernfs_info(sb);
+
+ return info->ns;
+}
+
+/**
+ * kernfs_mount_ns - kernfs mount helper
+ * @fs_type: file_system_type of the fs being mounted
+ * @flags: mount flags specified for the mount
+ * @root: kernfs_root of the hierarchy being mounted
+ * @magic: file system specific magic number
+ * @new_sb_created: tell the caller if we allocated a new superblock
+ * @ns: optional namespace tag of the mount
+ *
+ * This is to be called from each kernfs user's file_system_type->mount()
+ * implementation, which should pass through the specified @fs_type and
+ * @flags, and specify the hierarchy and namespace tag to mount via @root
+ * and @ns, respectively.
+ *
+ * The return value can be passed to the vfs layer verbatim.
+ */
+struct dentry *kernfs_mount_ns(struct file_system_type *fs_type, int flags,
+ struct kernfs_root *root, unsigned long magic,
+ bool *new_sb_created, const void *ns)
+{
+ struct super_block *sb;
+ struct kernfs_super_info *info;
+ int error;
+
+ info = kzalloc(sizeof(*info), GFP_KERNEL);
+ if (!info)
+ return ERR_PTR(-ENOMEM);
+
+ info->root = root;
+ info->ns = ns;
+
+ sb = sget_userns(fs_type, kernfs_test_super, kernfs_set_super, flags,
+ &init_user_ns, info);
+ if (IS_ERR(sb) || sb->s_fs_info != info)
+ kfree(info);
+ if (IS_ERR(sb))
+ return ERR_CAST(sb);
+
+ if (new_sb_created)
+ *new_sb_created = !sb->s_root;
+
+ if (!sb->s_root) {
+ struct kernfs_super_info *info = kernfs_info(sb);
+
+ error = kernfs_fill_super(sb, magic);
+ if (error) {
+ deactivate_locked_super(sb);
+ return ERR_PTR(error);
+ }
+ sb->s_flags |= MS_ACTIVE;
+
+ mutex_lock(&kernfs_mutex);
+ list_add(&info->node, &root->supers);
+ mutex_unlock(&kernfs_mutex);
+ }
+
+ return dget(sb->s_root);
+}
+
+/**
+ * kernfs_kill_sb - kill_sb for kernfs
+ * @sb: super_block being killed
+ *
+ * This can be used directly for file_system_type->kill_sb(). If a kernfs
+ * user needs extra cleanup, it can implement its own kill_sb() and call
+ * this function at the end.
+ */
+void kernfs_kill_sb(struct super_block *sb)
+{
+ struct kernfs_super_info *info = kernfs_info(sb);
+
+ mutex_lock(&kernfs_mutex);
+ list_del(&info->node);
+ mutex_unlock(&kernfs_mutex);
+
+ /*
+ * Remove the superblock from fs_supers/s_instances
+ * so we can't find it, before freeing kernfs_super_info.
+ */
+ kill_anon_super(sb);
+ kfree(info);
+}
+
+/**
+ * kernfs_pin_sb: try to pin the superblock associated with a kernfs_root
+ * @kernfs_root: the kernfs_root in question
+ * @ns: the namespace tag
+ *
+ * Pin the superblock so the superblock won't be destroyed in subsequent
+ * operations. This can be used to block ->kill_sb() which may be useful
+ * for kernfs users which dynamically manage superblocks.
+ *
+ * Returns NULL if there's no superblock associated to this kernfs_root, or
+ * -EINVAL if the superblock is being freed.
+ */
+struct super_block *kernfs_pin_sb(struct kernfs_root *root, const void *ns)
+{
+ struct kernfs_super_info *info;
+ struct super_block *sb = NULL;
+
+ mutex_lock(&kernfs_mutex);
+ list_for_each_entry(info, &root->supers, node) {
+ if (info->ns == ns) {
+ sb = info->sb;
+ if (!atomic_inc_not_zero(&info->sb->s_active))
+ sb = ERR_PTR(-EINVAL);
+ break;
+ }
+ }
+ mutex_unlock(&kernfs_mutex);
+ return sb;
+}
+
+void __init kernfs_init(void)
+{
+
+ /*
+ * the slab is freed in RCU context, so kernfs_find_and_get_node_by_ino
+ * can access the slab lock free. This could introduce stale nodes,
+ * please see how kernfs_find_and_get_node_by_ino filters out stale
+ * nodes.
+ */
+ kernfs_node_cache = kmem_cache_create("kernfs_node_cache",
+ sizeof(struct kernfs_node),
+ 0,
+ SLAB_PANIC | SLAB_TYPESAFE_BY_RCU,
+ NULL);
+}