staging: erofs: add super block operations
This commit adds erofs super block operations, including (u)mount, remount_fs, show_options, statfs, in addition to some private icache management functions. Signed-off-by: Miao Xie <miaoxie@huawei.com> Signed-off-by: Chao Yu <yuchao0@huawei.com> Signed-off-by: Gao Xiang <gaoxiang25@huawei.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Gao Xiang
Greg Kroah-Hartman
Родитель
bfb8674dc0
Коммит
ba2b77a820
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@ -0,0 +1,415 @@
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// SPDX-License-Identifier: GPL-2.0
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/*
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* linux/drivers/staging/erofs/super.c
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*
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* Copyright (C) 2017-2018 HUAWEI, Inc.
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* http://www.huawei.com/
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* Created by Gao Xiang <gaoxiang25@huawei.com>
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*
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* This file is subject to the terms and conditions of the GNU General Public
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* License. See the file COPYING in the main directory of the Linux
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* distribution for more details.
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*/
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#include <linux/module.h>
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#include <linux/buffer_head.h>
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#include <linux/statfs.h>
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#include <linux/parser.h>
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#include "internal.h"
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static struct kmem_cache *erofs_inode_cachep __read_mostly;
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static void init_once(void *ptr)
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{
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struct erofs_vnode *vi = ptr;
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inode_init_once(&vi->vfs_inode);
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}
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static int erofs_init_inode_cache(void)
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{
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erofs_inode_cachep = kmem_cache_create("erofs_inode",
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sizeof(struct erofs_vnode), 0,
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SLAB_RECLAIM_ACCOUNT, init_once);
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return erofs_inode_cachep != NULL ? 0 : -ENOMEM;
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}
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static void erofs_exit_inode_cache(void)
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{
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BUG_ON(erofs_inode_cachep == NULL);
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kmem_cache_destroy(erofs_inode_cachep);
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}
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static struct inode *alloc_inode(struct super_block *sb)
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{
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struct erofs_vnode *vi =
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kmem_cache_alloc(erofs_inode_cachep, GFP_KERNEL);
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if (vi == NULL)
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return NULL;
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/* zero out everything except vfs_inode */
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memset(vi, 0, offsetof(struct erofs_vnode, vfs_inode));
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return &vi->vfs_inode;
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}
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static void i_callback(struct rcu_head *head)
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{
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struct inode *inode = container_of(head, struct inode, i_rcu);
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struct erofs_vnode *vi = EROFS_V(inode);
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/* be careful RCU symlink path (see ext4_inode_info->i_data)! */
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if (is_inode_fast_symlink(inode))
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kfree(inode->i_link);
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kfree(vi->xattr_shared_xattrs);
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kmem_cache_free(erofs_inode_cachep, vi);
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}
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static void destroy_inode(struct inode *inode)
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{
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call_rcu(&inode->i_rcu, i_callback);
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}
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static int superblock_read(struct super_block *sb)
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{
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struct erofs_sb_info *sbi;
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struct buffer_head *bh;
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struct erofs_super_block *layout;
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unsigned blkszbits;
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int ret;
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bh = sb_bread(sb, 0);
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if (bh == NULL) {
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errln("cannot read erofs superblock");
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return -EIO;
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}
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sbi = EROFS_SB(sb);
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layout = (struct erofs_super_block *)((u8 *)bh->b_data
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+ EROFS_SUPER_OFFSET);
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ret = -EINVAL;
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if (le32_to_cpu(layout->magic) != EROFS_SUPER_MAGIC_V1) {
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errln("cannot find valid erofs superblock");
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goto out;
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}
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blkszbits = layout->blkszbits;
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/* 9(512 bytes) + LOG_SECTORS_PER_BLOCK == LOG_BLOCK_SIZE */
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if (unlikely(blkszbits != LOG_BLOCK_SIZE)) {
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errln("blksize %u isn't supported on this platform",
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1 << blkszbits);
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goto out;
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}
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sbi->blocks = le32_to_cpu(layout->blocks);
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sbi->meta_blkaddr = le32_to_cpu(layout->meta_blkaddr);
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sbi->islotbits = ffs(sizeof(struct erofs_inode_v1)) - 1;
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sbi->root_nid = le16_to_cpu(layout->root_nid);
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sbi->inos = le64_to_cpu(layout->inos);
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sbi->build_time = le64_to_cpu(layout->build_time);
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sbi->build_time_nsec = le32_to_cpu(layout->build_time_nsec);
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memcpy(&sb->s_uuid, layout->uuid, sizeof(layout->uuid));
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memcpy(sbi->volume_name, layout->volume_name,
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sizeof(layout->volume_name));
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ret = 0;
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out:
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brelse(bh);
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return ret;
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}
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static void default_options(struct erofs_sb_info *sbi)
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{
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}
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enum {
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Opt_err
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};
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static match_table_t erofs_tokens = {
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{Opt_err, NULL}
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};
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static int parse_options(struct super_block *sb, char *options)
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{
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substring_t args[MAX_OPT_ARGS];
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char *p;
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if (!options)
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return 0;
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while ((p = strsep(&options, ",")) != NULL) {
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int token;
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if (!*p)
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continue;
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args[0].to = args[0].from = NULL;
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token = match_token(p, erofs_tokens, args);
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switch (token) {
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default:
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errln("Unrecognized mount option \"%s\" "
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"or missing value", p);
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return -EINVAL;
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}
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}
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return 0;
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}
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static int erofs_read_super(struct super_block *sb,
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const char *dev_name, void *data, int silent)
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{
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struct inode *inode;
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struct erofs_sb_info *sbi;
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int err = -EINVAL;
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infoln("read_super, device -> %s", dev_name);
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infoln("options -> %s", (char *)data);
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if (unlikely(!sb_set_blocksize(sb, EROFS_BLKSIZ))) {
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errln("failed to set erofs blksize");
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goto err;
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}
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sbi = kzalloc(sizeof(struct erofs_sb_info), GFP_KERNEL);
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if (unlikely(sbi == NULL)) {
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err = -ENOMEM;
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goto err;
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}
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sb->s_fs_info = sbi;
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err = superblock_read(sb);
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if (err)
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goto err_sbread;
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sb->s_magic = EROFS_SUPER_MAGIC;
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sb->s_flags |= MS_RDONLY | MS_NOATIME;
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sb->s_maxbytes = MAX_LFS_FILESIZE;
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sb->s_time_gran = 1;
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sb->s_op = &erofs_sops;
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/* set erofs default mount options */
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default_options(sbi);
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err = parse_options(sb, data);
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if (err)
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goto err_parseopt;
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if (!silent)
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infoln("root inode @ nid %llu", ROOT_NID(sbi));
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/* get the root inode */
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inode = erofs_iget(sb, ROOT_NID(sbi), true);
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if (IS_ERR(inode)) {
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err = PTR_ERR(inode);
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goto err_iget;
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}
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if (!S_ISDIR(inode->i_mode)) {
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errln("rootino(nid %llu) is not a directory(i_mode %o)",
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ROOT_NID(sbi), inode->i_mode);
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err = -EINVAL;
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goto err_isdir;
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}
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sb->s_root = d_make_root(inode);
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if (sb->s_root == NULL) {
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err = -ENOMEM;
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goto err_makeroot;
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}
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/* save the device name to sbi */
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sbi->dev_name = __getname();
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if (sbi->dev_name == NULL) {
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err = -ENOMEM;
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goto err_devname;
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}
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snprintf(sbi->dev_name, PATH_MAX, "%s", dev_name);
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sbi->dev_name[PATH_MAX - 1] = '\0';
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/*
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* We already have a positive dentry, which was instantiated
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* by d_make_root. Just need to d_rehash it.
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*/
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d_rehash(sb->s_root);
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if (!silent)
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infoln("mounted on %s with opts: %s.", dev_name,
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(char *)data);
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return 0;
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/*
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* please add a label for each exit point and use
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* the following name convention, thus new features
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* can be integrated easily without renaming labels.
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*/
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err_devname:
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dput(sb->s_root);
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err_makeroot:
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err_isdir:
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if (sb->s_root == NULL)
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iput(inode);
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err_iget:
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err_parseopt:
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err_sbread:
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sb->s_fs_info = NULL;
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kfree(sbi);
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err:
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return err;
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}
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/*
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* could be triggered after deactivate_locked_super()
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* is called, thus including umount and failed to initialize.
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*/
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static void erofs_put_super(struct super_block *sb)
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{
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struct erofs_sb_info *sbi = EROFS_SB(sb);
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/* for cases which are failed in "read_super" */
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if (sbi == NULL)
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return;
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WARN_ON(sb->s_magic != EROFS_SUPER_MAGIC);
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infoln("unmounted for %s", sbi->dev_name);
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__putname(sbi->dev_name);
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kfree(sbi);
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sb->s_fs_info = NULL;
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}
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struct erofs_mount_private {
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const char *dev_name;
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char *options;
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};
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/* support mount_bdev() with options */
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static int erofs_fill_super(struct super_block *sb,
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void *_priv, int silent)
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{
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struct erofs_mount_private *priv = _priv;
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return erofs_read_super(sb, priv->dev_name,
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priv->options, silent);
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}
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static struct dentry *erofs_mount(
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struct file_system_type *fs_type, int flags,
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const char *dev_name, void *data)
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{
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struct erofs_mount_private priv = {
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.dev_name = dev_name,
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.options = data
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};
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return mount_bdev(fs_type, flags, dev_name,
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&priv, erofs_fill_super);
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}
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static void erofs_kill_sb(struct super_block *sb)
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{
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kill_block_super(sb);
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}
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static struct file_system_type erofs_fs_type = {
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.owner = THIS_MODULE,
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.name = "erofs",
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.mount = erofs_mount,
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.kill_sb = erofs_kill_sb,
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.fs_flags = FS_REQUIRES_DEV,
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};
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MODULE_ALIAS_FS("erofs");
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static int __init erofs_module_init(void)
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{
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int err;
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erofs_check_ondisk_layout_definitions();
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infoln("initializing erofs " EROFS_VERSION);
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err = erofs_init_inode_cache();
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if (err)
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goto icache_err;
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err = register_filesystem(&erofs_fs_type);
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if (err)
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goto fs_err;
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infoln("successfully to initialize erofs");
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return 0;
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fs_err:
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erofs_exit_inode_cache();
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icache_err:
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return err;
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}
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static void __exit erofs_module_exit(void)
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{
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unregister_filesystem(&erofs_fs_type);
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erofs_exit_inode_cache();
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infoln("successfully finalize erofs");
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}
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/* get filesystem statistics */
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static int erofs_statfs(struct dentry *dentry, struct kstatfs *buf)
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{
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struct super_block *sb = dentry->d_sb;
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struct erofs_sb_info *sbi = EROFS_SB(sb);
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u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
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buf->f_type = sb->s_magic;
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buf->f_bsize = EROFS_BLKSIZ;
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buf->f_blocks = sbi->blocks;
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buf->f_bfree = buf->f_bavail = 0;
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buf->f_files = ULLONG_MAX;
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buf->f_ffree = ULLONG_MAX - sbi->inos;
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buf->f_namelen = EROFS_NAME_LEN;
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buf->f_fsid.val[0] = (u32)id;
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buf->f_fsid.val[1] = (u32)(id >> 32);
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return 0;
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}
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static int erofs_show_options(struct seq_file *seq, struct dentry *root)
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{
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return 0;
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}
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static int erofs_remount(struct super_block *sb, int *flags, char *data)
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{
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BUG_ON(!sb_rdonly(sb));
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*flags |= MS_RDONLY;
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return 0;
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}
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const struct super_operations erofs_sops = {
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.put_super = erofs_put_super,
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.alloc_inode = alloc_inode,
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.destroy_inode = destroy_inode,
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.statfs = erofs_statfs,
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.show_options = erofs_show_options,
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.remount_fs = erofs_remount,
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};
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module_init(erofs_module_init);
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module_exit(erofs_module_exit);
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MODULE_DESCRIPTION("Enhanced ROM File System");
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MODULE_AUTHOR("Gao Xiang, Yu Chao, Miao Xie, CONSUMER BG, HUAWEI Inc.");
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MODULE_LICENSE("GPL");
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