Orange Pi5 kernel

^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   1) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   2)  * Resizable simple ram filesystem for Linux.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   3)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   4)  * Copyright (C) 2000 Linus Torvalds.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   5)  *               2000 Transmeta Corp.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   6)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   7)  * Usage limits added by David Gibson, Linuxcare Australia.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   8)  * This file is released under the GPL.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   9)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  10) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  11) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  12)  * NOTE! This filesystem is probably most useful
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  13)  * not as a real filesystem, but as an example of
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  14)  * how virtual filesystems can be written.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  15)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  16)  * It doesn't get much simpler than this. Consider
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  17)  * that this file implements the full semantics of
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  18)  * a POSIX-compliant read-write filesystem.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  19)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  20)  * Note in particular how the filesystem does not
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  21)  * need to implement any data structures of its own
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  22)  * to keep track of the virtual data: using the VFS
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  23)  * caches is sufficient.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  24)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  25) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  26) #include <linux/fs.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  27) #include <linux/pagemap.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  28) #include <linux/highmem.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  29) #include <linux/time.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  30) #include <linux/init.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  31) #include <linux/string.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  32) #include <linux/backing-dev.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  33) #include <linux/ramfs.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  34) #include <linux/sched.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  35) #include <linux/parser.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  36) #include <linux/magic.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  37) #include <linux/slab.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  38) #include <linux/uaccess.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  39) #include <linux/fs_context.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  40) #include <linux/fs_parser.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  41) #include "internal.h"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  42) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  43) struct ramfs_mount_opts {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  44) 	umode_t mode;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  45) };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  46) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  47) struct ramfs_fs_info {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  48) 	struct ramfs_mount_opts mount_opts;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  49) };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  50) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  51) #define RAMFS_DEFAULT_MODE	0755
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  52) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  53) static const struct super_operations ramfs_ops;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  54) static const struct inode_operations ramfs_dir_inode_operations;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  55) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  56) static const struct address_space_operations ramfs_aops = {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  57) 	.readpage	= simple_readpage,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  58) 	.write_begin	= simple_write_begin,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  59) 	.write_end	= simple_write_end,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  60) 	.set_page_dirty	= __set_page_dirty_no_writeback,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  61) };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  62) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  63) struct inode *ramfs_get_inode(struct super_block *sb,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  64) 				const struct inode *dir, umode_t mode, dev_t dev)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  65) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  66) 	struct inode * inode = new_inode(sb);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  67) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  68) 	if (inode) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  69) 		inode->i_ino = get_next_ino();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  70) 		inode_init_owner(inode, dir, mode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  71) 		inode->i_mapping->a_ops = &ramfs_aops;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  72) 		mapping_set_gfp_mask(inode->i_mapping, GFP_HIGHUSER);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  73) 		mapping_set_unevictable(inode->i_mapping);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  74) 		inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  75) 		switch (mode & S_IFMT) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  76) 		default:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  77) 			init_special_inode(inode, mode, dev);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  78) 			break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  79) 		case S_IFREG:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  80) 			inode->i_op = &ramfs_file_inode_operations;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  81) 			inode->i_fop = &ramfs_file_operations;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  82) 			break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  83) 		case S_IFDIR:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  84) 			inode->i_op = &ramfs_dir_inode_operations;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  85) 			inode->i_fop = &simple_dir_operations;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  86) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  87) 			/* directory inodes start off with i_nlink == 2 (for "." entry) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  88) 			inc_nlink(inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  89) 			break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  90) 		case S_IFLNK:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  91) 			inode->i_op = &page_symlink_inode_operations;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  92) 			inode_nohighmem(inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  93) 			break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  94) 		}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  95) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  96) 	return inode;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  97) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  98) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  99) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 100)  * File creation. Allocate an inode, and we're done..
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 101)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 102) /* SMP-safe */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 103) static int
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 104) ramfs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t dev)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 105) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 106) 	struct inode * inode = ramfs_get_inode(dir->i_sb, dir, mode, dev);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 107) 	int error = -ENOSPC;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 108) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 109) 	if (inode) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 110) 		d_instantiate(dentry, inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 111) 		dget(dentry);	/* Extra count - pin the dentry in core */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 112) 		error = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 113) 		dir->i_mtime = dir->i_ctime = current_time(dir);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 114) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 115) 	return error;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 116) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 117) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 118) static int ramfs_mkdir(struct inode * dir, struct dentry * dentry, umode_t mode)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 119) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 120) 	int retval = ramfs_mknod(dir, dentry, mode | S_IFDIR, 0);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 121) 	if (!retval)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 122) 		inc_nlink(dir);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 123) 	return retval;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 124) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 125) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 126) static int ramfs_create(struct inode *dir, struct dentry *dentry, umode_t mode, bool excl)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 127) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 128) 	return ramfs_mknod(dir, dentry, mode | S_IFREG, 0);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 129) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 130) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 131) static int ramfs_symlink(struct inode * dir, struct dentry *dentry, const char * symname)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 132) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 133) 	struct inode *inode;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 134) 	int error = -ENOSPC;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 135) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 136) 	inode = ramfs_get_inode(dir->i_sb, dir, S_IFLNK|S_IRWXUGO, 0);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 137) 	if (inode) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 138) 		int l = strlen(symname)+1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 139) 		error = page_symlink(inode, symname, l);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 140) 		if (!error) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 141) 			d_instantiate(dentry, inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 142) 			dget(dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 143) 			dir->i_mtime = dir->i_ctime = current_time(dir);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 144) 		} else
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 145) 			iput(inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 146) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 147) 	return error;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 148) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 149) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 150) static const struct inode_operations ramfs_dir_inode_operations = {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 151) 	.create		= ramfs_create,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 152) 	.lookup		= simple_lookup,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 153) 	.link		= simple_link,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 154) 	.unlink		= simple_unlink,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 155) 	.symlink	= ramfs_symlink,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 156) 	.mkdir		= ramfs_mkdir,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 157) 	.rmdir		= simple_rmdir,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 158) 	.mknod		= ramfs_mknod,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 159) 	.rename		= simple_rename,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 160) };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 161) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 162) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 163)  * Display the mount options in /proc/mounts.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 164)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 165) static int ramfs_show_options(struct seq_file *m, struct dentry *root)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 166) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 167) 	struct ramfs_fs_info *fsi = root->d_sb->s_fs_info;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 168) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 169) 	if (fsi->mount_opts.mode != RAMFS_DEFAULT_MODE)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 170) 		seq_printf(m, ",mode=%o", fsi->mount_opts.mode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 171) 	return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 172) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 173) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 174) static const struct super_operations ramfs_ops = {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 175) 	.statfs		= simple_statfs,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 176) 	.drop_inode	= generic_delete_inode,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 177) 	.show_options	= ramfs_show_options,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 178) };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 179) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 180) enum ramfs_param {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 181) 	Opt_mode,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 182) };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 183) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 184) const struct fs_parameter_spec ramfs_fs_parameters[] = {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 185) 	fsparam_u32oct("mode",	Opt_mode),
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 186) 	{}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 187) };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 188) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 189) static int ramfs_parse_param(struct fs_context *fc, struct fs_parameter *param)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 190) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 191) 	struct fs_parse_result result;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 192) 	struct ramfs_fs_info *fsi = fc->s_fs_info;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 193) 	int opt;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 194) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 195) 	opt = fs_parse(fc, ramfs_fs_parameters, param, &result);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 196) 	if (opt < 0) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 197) 		/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 198) 		 * We might like to report bad mount options here;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 199) 		 * but traditionally ramfs has ignored all mount options,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 200) 		 * and as it is used as a !CONFIG_SHMEM simple substitute
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 201) 		 * for tmpfs, better continue to ignore other mount options.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 202) 		 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 203) 		if (opt == -ENOPARAM)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 204) 			opt = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 205) 		return opt;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 206) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 207) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 208) 	switch (opt) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 209) 	case Opt_mode:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 210) 		fsi->mount_opts.mode = result.uint_32 & S_IALLUGO;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 211) 		break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 212) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 213) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 214) 	return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 215) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 216) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 217) static int ramfs_fill_super(struct super_block *sb, struct fs_context *fc)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 218) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 219) 	struct ramfs_fs_info *fsi = sb->s_fs_info;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 220) 	struct inode *inode;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 221) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 222) 	sb->s_maxbytes		= MAX_LFS_FILESIZE;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 223) 	sb->s_blocksize		= PAGE_SIZE;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 224) 	sb->s_blocksize_bits	= PAGE_SHIFT;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 225) 	sb->s_magic		= RAMFS_MAGIC;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 226) 	sb->s_op		= &ramfs_ops;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 227) 	sb->s_time_gran		= 1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 228) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 229) 	inode = ramfs_get_inode(sb, NULL, S_IFDIR | fsi->mount_opts.mode, 0);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 230) 	sb->s_root = d_make_root(inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 231) 	if (!sb->s_root)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 232) 		return -ENOMEM;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 233) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 234) 	return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 235) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 236) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 237) static int ramfs_get_tree(struct fs_context *fc)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 238) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 239) 	return get_tree_nodev(fc, ramfs_fill_super);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 240) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 241) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 242) static void ramfs_free_fc(struct fs_context *fc)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 243) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 244) 	kfree(fc->s_fs_info);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 245) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 246) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 247) static const struct fs_context_operations ramfs_context_ops = {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 248) 	.free		= ramfs_free_fc,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 249) 	.parse_param	= ramfs_parse_param,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 250) 	.get_tree	= ramfs_get_tree,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 251) };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 252) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 253) int ramfs_init_fs_context(struct fs_context *fc)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 254) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 255) 	struct ramfs_fs_info *fsi;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 256) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 257) 	fsi = kzalloc(sizeof(*fsi), GFP_KERNEL);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 258) 	if (!fsi)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 259) 		return -ENOMEM;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 260) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 261) 	fsi->mount_opts.mode = RAMFS_DEFAULT_MODE;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 262) 	fc->s_fs_info = fsi;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 263) 	fc->ops = &ramfs_context_ops;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 264) 	return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 265) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 266) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 267) static void ramfs_kill_sb(struct super_block *sb)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 268) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 269) 	kfree(sb->s_fs_info);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 270) 	kill_litter_super(sb);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 271) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 272) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 273) static struct file_system_type ramfs_fs_type = {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 274) 	.name		= "ramfs",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 275) 	.init_fs_context = ramfs_init_fs_context,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 276) 	.parameters	= ramfs_fs_parameters,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 277) 	.kill_sb	= ramfs_kill_sb,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 278) 	.fs_flags	= FS_USERNS_MOUNT,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 279) };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 280) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 281) static int __init init_ramfs_fs(void)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 282) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 283) 	return register_filesystem(&ramfs_fs_type);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 284) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 285) fs_initcall(init_ramfs_fs);