1 files changed, 443 insertions, 0 deletions
diff --git a/fs/ext2/namei.c b/fs/ext2/namei.c
new file mode 100644
index 000000000..9125eab85
--- /dev/null
+++ b/fs/ext2/namei.c
@@ -0,0 +1,443 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * linux/fs/ext2/namei.c
+ *
+ * Rewrite to pagecache. Almost all code had been changed, so blame me
+ * if the things go wrong. Please, send bug reports to
+ * viro@parcelfarce.linux.theplanet.co.uk
+ *
+ * Stuff here is basically a glue between the VFS and generic UNIXish
+ * filesystem that keeps everything in pagecache. All knowledge of the
+ * directory layout is in fs/ext2/dir.c - it turned out to be easily separatable
+ * and it's easier to debug that way. In principle we might want to
+ * generalize that a bit and turn it into a library. Or not.
+ *
+ * The only non-static object here is ext2_dir_inode_operations.
+ *
+ * TODO: get rid of kmap() use, add readahead.
+ *
+ * Copyright (C) 1992, 1993, 1994, 1995
+ * Remy Card (card@masi.ibp.fr)
+ * Laboratoire MASI - Institut Blaise Pascal
+ * Universite Pierre et Marie Curie (Paris VI)
+ *
+ *  from
+ *
+ *  linux/fs/minix/namei.c
+ *
+ *  Copyright (C) 1991, 1992  Linus Torvalds
+ *
+ *  Big-endian to little-endian byte-swapping/bitmaps by
+ *        David S. Miller (davem@caip.rutgers.edu), 1995
+ */
+
+#include <linux/pagemap.h>
+#include <linux/quotaops.h>
+#include "ext2.h"
+#include "xattr.h"
+#include "acl.h"
+
+static inline int ext2_add_nondir(struct dentry *dentry, struct inode *inode)
+{
+	int err = ext2_add_link(dentry, inode);
+	if (!err) {
+		d_instantiate_new(dentry, inode);
+		return 0;
+	}
+	inode_dec_link_count(inode);
+	discard_new_inode(inode);
+	return err;
+}
+
+/*
+ * Methods themselves.
+ */
+
+static struct dentry *ext2_lookup(struct inode * dir, struct dentry *dentry, unsigned int flags)
+{
+	struct inode * inode;
+	ino_t ino;
+	int res;
+	
+	if (dentry->d_name.len > EXT2_NAME_LEN)
+		return ERR_PTR(-ENAMETOOLONG);
+
+	res = ext2_inode_by_name(dir, &dentry->d_name, &ino);
+	if (res) {
+		if (res != -ENOENT)
+			return ERR_PTR(res);
+		inode = NULL;
+	} else {
+		inode = ext2_iget(dir->i_sb, ino);
+		if (inode == ERR_PTR(-ESTALE)) {
+			ext2_error(dir->i_sb, __func__,
+					"deleted inode referenced: %lu",
+					(unsigned long) ino);
+			return ERR_PTR(-EIO);
+		}
+	}
+	return d_splice_alias(inode, dentry);
+}
+
+struct dentry *ext2_get_parent(struct dentry *child)
+{
+	ino_t ino;
+	int res;
+
+	res = ext2_inode_by_name(d_inode(child), &dotdot_name, &ino);
+	if (res)
+		return ERR_PTR(res);
+
+	return d_obtain_alias(ext2_iget(child->d_sb, ino));
+} 
+
+/*
+ * By the time this is called, we already have created
+ * the directory cache entry for the new file, but it
+ * is so far negative - it has no inode.
+ *
+ * If the create succeeds, we fill in the inode information
+ * with d_instantiate(). 
+ */
+static int ext2_create (struct user_namespace * mnt_userns,
+			struct inode * dir, struct dentry * dentry,
+			umode_t mode, bool excl)
+{
+	struct inode *inode;
+	int err;
+
+	err = dquot_initialize(dir);
+	if (err)
+		return err;
+
+	inode = ext2_new_inode(dir, mode, &dentry->d_name);
+	if (IS_ERR(inode))
+		return PTR_ERR(inode);
+
+	ext2_set_file_ops(inode);
+	mark_inode_dirty(inode);
+	return ext2_add_nondir(dentry, inode);
+}
+
+static int ext2_tmpfile(struct user_namespace *mnt_userns, struct inode *dir,
+			struct file *file, umode_t mode)
+{
+	struct inode *inode = ext2_new_inode(dir, mode, NULL);
+	if (IS_ERR(inode))
+		return PTR_ERR(inode);
+
+	ext2_set_file_ops(inode);
+	mark_inode_dirty(inode);
+	d_tmpfile(file, inode);
+	unlock_new_inode(inode);
+	return finish_open_simple(file, 0);
+}
+
+static int ext2_mknod (struct user_namespace * mnt_userns, struct inode * dir,
+	struct dentry *dentry, umode_t mode, dev_t rdev)
+{
+	struct inode * inode;
+	int err;
+
+	err = dquot_initialize(dir);
+	if (err)
+		return err;
+
+	inode = ext2_new_inode (dir, mode, &dentry->d_name);
+	err = PTR_ERR(inode);
+	if (!IS_ERR(inode)) {
+		init_special_inode(inode, inode->i_mode, rdev);
+		inode->i_op = &ext2_special_inode_operations;
+		mark_inode_dirty(inode);
+		err = ext2_add_nondir(dentry, inode);
+	}
+	return err;
+}
+
+static int ext2_symlink (struct user_namespace * mnt_userns, struct inode * dir,
+	struct dentry * dentry, const char * symname)
+{
+	struct super_block * sb = dir->i_sb;
+	int err = -ENAMETOOLONG;
+	unsigned l = strlen(symname)+1;
+	struct inode * inode;
+
+	if (l > sb->s_blocksize)
+		goto out;
+
+	err = dquot_initialize(dir);
+	if (err)
+		goto out;
+
+	inode = ext2_new_inode (dir, S_IFLNK | S_IRWXUGO, &dentry->d_name);
+	err = PTR_ERR(inode);
+	if (IS_ERR(inode))
+		goto out;
+
+	if (l > sizeof (EXT2_I(inode)->i_data)) {
+		/* slow symlink */
+		inode->i_op = &ext2_symlink_inode_operations;
+		inode_nohighmem(inode);
+		inode->i_mapping->a_ops = &ext2_aops;
+		err = page_symlink(inode, symname, l);
+		if (err)
+			goto out_fail;
+	} else {
+		/* fast symlink */
+		inode->i_op = &ext2_fast_symlink_inode_operations;
+		inode->i_link = (char*)EXT2_I(inode)->i_data;
+		memcpy(inode->i_link, symname, l);
+		inode->i_size = l-1;
+	}
+	mark_inode_dirty(inode);
+
+	err = ext2_add_nondir(dentry, inode);
+out:
+	return err;
+
+out_fail:
+	inode_dec_link_count(inode);
+	discard_new_inode(inode);
+	goto out;
+}
+
+static int ext2_link (struct dentry * old_dentry, struct inode * dir,
+	struct dentry *dentry)
+{
+	struct inode *inode = d_inode(old_dentry);
+	int err;
+
+	err = dquot_initialize(dir);
+	if (err)
+		return err;
+
+	inode->i_ctime = current_time(inode);
+	inode_inc_link_count(inode);
+	ihold(inode);
+
+	err = ext2_add_link(dentry, inode);
+	if (!err) {
+		d_instantiate(dentry, inode);
+		return 0;
+	}
+	inode_dec_link_count(inode);
+	iput(inode);
+	return err;
+}
+
+static int ext2_mkdir(struct user_namespace * mnt_userns,
+	struct inode * dir, struct dentry * dentry, umode_t mode)
+{
+	struct inode * inode;
+	int err;
+
+	err = dquot_initialize(dir);
+	if (err)
+		return err;
+
+	inode_inc_link_count(dir);
+
+	inode = ext2_new_inode(dir, S_IFDIR | mode, &dentry->d_name);
+	err = PTR_ERR(inode);
+	if (IS_ERR(inode))
+		goto out_dir;
+
+	inode->i_op = &ext2_dir_inode_operations;
+	inode->i_fop = &ext2_dir_operations;
+	inode->i_mapping->a_ops = &ext2_aops;
+
+	inode_inc_link_count(inode);
+
+	err = ext2_make_empty(inode, dir);
+	if (err)
+		goto out_fail;
+
+	err = ext2_add_link(dentry, inode);
+	if (err)
+		goto out_fail;
+
+	d_instantiate_new(dentry, inode);
+out:
+	return err;
+
+out_fail:
+	inode_dec_link_count(inode);
+	inode_dec_link_count(inode);
+	discard_new_inode(inode);
+out_dir:
+	inode_dec_link_count(dir);
+	goto out;
+}
+
+static int ext2_unlink(struct inode * dir, struct dentry *dentry)
+{
+	struct inode * inode = d_inode(dentry);
+	struct ext2_dir_entry_2 * de;
+	struct page * page;
+	void *page_addr;
+	int err;
+
+	err = dquot_initialize(dir);
+	if (err)
+		goto out;
+
+	de = ext2_find_entry(dir, &dentry->d_name, &page, &page_addr);
+	if (IS_ERR(de)) {
+		err = PTR_ERR(de);
+		goto out;
+	}
+
+	err = ext2_delete_entry (de, page, page_addr);
+	ext2_put_page(page, page_addr);
+	if (err)
+		goto out;
+
+	inode->i_ctime = dir->i_ctime;
+	inode_dec_link_count(inode);
+	err = 0;
+out:
+	return err;
+}
+
+static int ext2_rmdir (struct inode * dir, struct dentry *dentry)
+{
+	struct inode * inode = d_inode(dentry);
+	int err = -ENOTEMPTY;
+
+	if (ext2_empty_dir(inode)) {
+		err = ext2_unlink(dir, dentry);
+		if (!err) {
+			inode->i_size = 0;
+			inode_dec_link_count(inode);
+			inode_dec_link_count(dir);
+		}
+	}
+	return err;
+}
+
+static int ext2_rename (struct user_namespace * mnt_userns,
+			struct inode * old_dir, struct dentry * old_dentry,
+			struct inode * new_dir, struct dentry * new_dentry,
+			unsigned int flags)
+{
+	struct inode * old_inode = d_inode(old_dentry);
+	struct inode * new_inode = d_inode(new_dentry);
+	struct page * dir_page = NULL;
+	void *dir_page_addr;
+	struct ext2_dir_entry_2 * dir_de = NULL;
+	struct page * old_page;
+	void *old_page_addr;
+	struct ext2_dir_entry_2 * old_de;
+	int err;
+
+	if (flags & ~RENAME_NOREPLACE)
+		return -EINVAL;
+
+	err = dquot_initialize(old_dir);
+	if (err)
+		goto out;
+
+	err = dquot_initialize(new_dir);
+	if (err)
+		goto out;
+
+	old_de = ext2_find_entry(old_dir, &old_dentry->d_name, &old_page,
+				 &old_page_addr);
+	if (IS_ERR(old_de)) {
+		err = PTR_ERR(old_de);
+		goto out;
+	}
+
+	if (S_ISDIR(old_inode->i_mode)) {
+		err = -EIO;
+		dir_de = ext2_dotdot(old_inode, &dir_page, &dir_page_addr);
+		if (!dir_de)
+			goto out_old;
+	}
+
+	if (new_inode) {
+		void *page_addr;
+		struct page *new_page;
+		struct ext2_dir_entry_2 *new_de;
+
+		err = -ENOTEMPTY;
+		if (dir_de && !ext2_empty_dir (new_inode))
+			goto out_dir;
+
+		new_de = ext2_find_entry(new_dir, &new_dentry->d_name,
+					 &new_page, &page_addr);
+		if (IS_ERR(new_de)) {
+			err = PTR_ERR(new_de);
+			goto out_dir;
+		}
+		ext2_set_link(new_dir, new_de, new_page, page_addr, old_inode, 1);
+		ext2_put_page(new_page, page_addr);
+		new_inode->i_ctime = current_time(new_inode);
+		if (dir_de)
+			drop_nlink(new_inode);
+		inode_dec_link_count(new_inode);
+	} else {
+		err = ext2_add_link(new_dentry, old_inode);
+		if (err)
+			goto out_dir;
+		if (dir_de)
+			inode_inc_link_count(new_dir);
+	}
+
+	/*
+	 * Like most other Unix systems, set the ctime for inodes on a
+ 	 * rename.
+	 */
+	old_inode->i_ctime = current_time(old_inode);
+	mark_inode_dirty(old_inode);
+
+	ext2_delete_entry(old_de, old_page, old_page_addr);
+
+	if (dir_de) {
+		if (old_dir != new_dir)
+			ext2_set_link(old_inode, dir_de, dir_page,
+				      dir_page_addr, new_dir, 0);
+
+		ext2_put_page(dir_page, dir_page_addr);
+		inode_dec_link_count(old_dir);
+	}
+
+	ext2_put_page(old_page, old_page_addr);
+	return 0;
+
+out_dir:
+	if (dir_de)
+		ext2_put_page(dir_page, dir_page_addr);
+out_old:
+	ext2_put_page(old_page, old_page_addr);
+out:
+	return err;
+}
+
+const struct inode_operations ext2_dir_inode_operations = {
+	.create		= ext2_create,
+	.lookup		= ext2_lookup,
+	.link		= ext2_link,
+	.unlink		= ext2_unlink,
+	.symlink	= ext2_symlink,
+	.mkdir		= ext2_mkdir,
+	.rmdir		= ext2_rmdir,
+	.mknod		= ext2_mknod,
+	.rename		= ext2_rename,
+	.listxattr	= ext2_listxattr,
+	.getattr	= ext2_getattr,
+	.setattr	= ext2_setattr,
+	.get_acl	= ext2_get_acl,
+	.set_acl	= ext2_set_acl,
+	.tmpfile	= ext2_tmpfile,
+	.fileattr_get	= ext2_fileattr_get,
+	.fileattr_set	= ext2_fileattr_set,
+};
+
+const struct inode_operations ext2_special_inode_operations = {
+	.listxattr	= ext2_listxattr,
+	.getattr	= ext2_getattr,
+	.setattr	= ext2_setattr,
+	.get_acl	= ext2_get_acl,
+	.set_acl	= ext2_set_acl,
+};