Initial commit: OpenHarmony-v4.0-ReleaseOpenHarmony-v4.0-Release

1 files changed, 397 insertions, 0 deletions

diff --git a/fs/kernfs/mount.c b/fs/kernfs/mount.c
new file mode 100644
index 000000000..9dc7e7a64
--- /dev/null
+++ b/fs/kernfs/mount.c
@@ -0,0 +1,397 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * 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>
+ */
+
+#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, *kernfs_iattrs_cache;
+
+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,
+
+        .show_options   = kernfs_sop_show_options,
+        .show_path      = kernfs_sop_show_path,
+};
+
+static int kernfs_encode_fh(struct inode *inode, __u32 *fh, int *max_len,
+                            struct inode *parent)
+{
+        struct kernfs_node *kn = inode->i_private;
+
+        if (*max_len < 2) {
+                *max_len = 2;
+                return FILEID_INVALID;
+        }
+
+        *max_len = 2;
+        *(u64 *)fh = kn->id;
+        return FILEID_KERNFS;
+}
+
+static struct dentry *__kernfs_fh_to_dentry(struct super_block *sb,
+                                            struct fid *fid, int fh_len,
+                                            int fh_type, bool get_parent)
+{
+        struct kernfs_super_info *info = kernfs_info(sb);
+        struct kernfs_node *kn;
+        struct inode *inode;
+        u64 id;
+
+        if (fh_len < 2)
+                return NULL;
+
+        switch (fh_type) {
+        case FILEID_KERNFS:
+                id = *(u64 *)fid;
+                break;
+        case FILEID_INO32_GEN:
+        case FILEID_INO32_GEN_PARENT:
+                /*
+                 * blk_log_action() exposes "LOW32,HIGH32" pair without
+                 * type and userland can call us with generic fid
+                 * constructed from them.  Combine it back to ID.  See
+                 * blk_log_action().
+                 */
+                id = ((u64)fid->i32.gen << 32) | fid->i32.ino;
+                break;
+        default:
+                return NULL;
+        }
+
+        kn = kernfs_find_and_get_node_by_id(info->root, id);
+        if (!kn)
+                return ERR_PTR(-ESTALE);
+
+        if (get_parent) {
+                struct kernfs_node *parent;
+
+                parent = kernfs_get_parent(kn);
+                kernfs_put(kn);
+                kn = parent;
+                if (!kn)
+                        return ERR_PTR(-ESTALE);
+        }
+
+        inode = kernfs_get_inode(sb, kn);
+        kernfs_put(kn);
+        if (!inode)
+                return ERR_PTR(-ESTALE);
+
+        return d_obtain_alias(inode);
+}
+
+static struct dentry *kernfs_fh_to_dentry(struct super_block *sb,
+                                          struct fid *fid, int fh_len,
+                                          int fh_type)
+{
+        return __kernfs_fh_to_dentry(sb, fid, fh_len, fh_type, false);
+}
+
+static struct dentry *kernfs_fh_to_parent(struct super_block *sb,
+                                          struct fid *fid, int fh_len,
+                                          int fh_type)
+{
+        return __kernfs_fh_to_dentry(sb, fid, fh_len, fh_type, true);
+}
+
+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 = {
+        .encode_fh      = kernfs_encode_fh,
+        .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_positive_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, struct kernfs_fs_context *kfc)
+{
+        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 = kfc->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;
+
+        /* sysfs dentries and inodes don't require IO to create */
+        sb->s_shrink.seeks = 0;
+
+        /* 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, struct fs_context *fc)
+{
+        struct kernfs_super_info *sb_info = kernfs_info(sb);
+        struct kernfs_super_info *info = fc->s_fs_info;
+
+        return sb_info->root == info->root && sb_info->ns == info->ns;
+}
+
+static int kernfs_set_super(struct super_block *sb, struct fs_context *fc)
+{
+        struct kernfs_fs_context *kfc = fc->fs_private;
+
+        kfc->ns_tag = NULL;
+        return set_anon_super_fc(sb, fc);
+}
+
+/**
+ * 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_get_tree - kernfs filesystem access/retrieval helper
+ * @fc: The filesystem context.
+ *
+ * This is to be called from each kernfs user's fs_context->ops->get_tree()
+ * implementation, which should set the specified ->@fs_type and ->@flags, and
+ * specify the hierarchy and namespace tag to mount via ->@root and ->@ns,
+ * respectively.
+ */
+int kernfs_get_tree(struct fs_context *fc)
+{
+        struct kernfs_fs_context *kfc = fc->fs_private;
+        struct super_block *sb;
+        struct kernfs_super_info *info;
+        int error;
+
+        info = kzalloc(sizeof(*info), GFP_KERNEL);
+        if (!info)
+                return -ENOMEM;
+
+        info->root = kfc->root;
+        info->ns = kfc->ns_tag;
+        INIT_LIST_HEAD(&info->node);
+
+        fc->s_fs_info = info;
+        sb = sget_fc(fc, kernfs_test_super, kernfs_set_super);
+        if (IS_ERR(sb))
+                return PTR_ERR(sb);
+
+        if (!sb->s_root) {
+                struct kernfs_super_info *info = kernfs_info(sb);
+
+                kfc->new_sb_created = true;
+
+                error = kernfs_fill_super(sb, kfc);
+                if (error) {
+                        deactivate_locked_super(sb);
+                        return error;
+                }
+                sb->s_flags |= SB_ACTIVE;
+
+                mutex_lock(&kernfs_mutex);
+                list_add(&info->node, &info->root->supers);
+                mutex_unlock(&kernfs_mutex);
+        }
+
+        fc->root = dget(sb->s_root);
+        return 0;
+}
+
+void kernfs_free_fs_context(struct fs_context *fc)
+{
+        /* Note that we don't deal with kfc->ns_tag here. */
+        kfree(fc->s_fs_info);
+        fc->s_fs_info = NULL;
+}
+
+/**
+ * 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);
+}
+
+void __init kernfs_init(void)
+{
+        kernfs_node_cache = kmem_cache_create("kernfs_node_cache",
+                                              sizeof(struct kernfs_node),
+                                              0, SLAB_PANIC, NULL);
+
+        /* Creates slab cache for kernfs inode attributes */
+        kernfs_iattrs_cache  = kmem_cache_create("kernfs_iattrs_cache",
+                                              sizeof(struct kernfs_iattrs),
+                                              0, SLAB_PANIC, NULL);
+}