352 строки
8.1 KiB
C
352 строки
8.1 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* super.c
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*
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* Copyright (c) 1999 Al Smith
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*
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* Portions derived from work (c) 1995,1996 Christian Vogelgsang.
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*/
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/exportfs.h>
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#include <linux/slab.h>
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#include <linux/buffer_head.h>
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#include <linux/vfs.h>
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#include <linux/blkdev.h>
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#include "efs.h"
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#include <linux/efs_vh.h>
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#include <linux/efs_fs_sb.h>
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static int efs_statfs(struct dentry *dentry, struct kstatfs *buf);
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static int efs_fill_super(struct super_block *s, void *d, int silent);
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static struct dentry *efs_mount(struct file_system_type *fs_type,
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int flags, const char *dev_name, void *data)
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{
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return mount_bdev(fs_type, flags, dev_name, data, efs_fill_super);
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}
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static void efs_kill_sb(struct super_block *s)
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{
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struct efs_sb_info *sbi = SUPER_INFO(s);
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kill_block_super(s);
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kfree(sbi);
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}
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static struct file_system_type efs_fs_type = {
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.owner = THIS_MODULE,
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.name = "efs",
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.mount = efs_mount,
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.kill_sb = efs_kill_sb,
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.fs_flags = FS_REQUIRES_DEV,
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};
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MODULE_ALIAS_FS("efs");
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static struct pt_types sgi_pt_types[] = {
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{0x00, "SGI vh"},
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{0x01, "SGI trkrepl"},
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{0x02, "SGI secrepl"},
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{0x03, "SGI raw"},
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{0x04, "SGI bsd"},
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{SGI_SYSV, "SGI sysv"},
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{0x06, "SGI vol"},
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{SGI_EFS, "SGI efs"},
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{0x08, "SGI lv"},
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{0x09, "SGI rlv"},
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{0x0A, "SGI xfs"},
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{0x0B, "SGI xfslog"},
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{0x0C, "SGI xlv"},
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{0x82, "Linux swap"},
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{0x83, "Linux native"},
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{0, NULL}
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};
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static struct kmem_cache * efs_inode_cachep;
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static struct inode *efs_alloc_inode(struct super_block *sb)
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{
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struct efs_inode_info *ei;
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ei = kmem_cache_alloc(efs_inode_cachep, GFP_KERNEL);
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if (!ei)
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return NULL;
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return &ei->vfs_inode;
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}
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static void efs_free_inode(struct inode *inode)
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{
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kmem_cache_free(efs_inode_cachep, INODE_INFO(inode));
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}
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static void init_once(void *foo)
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{
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struct efs_inode_info *ei = (struct efs_inode_info *) foo;
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inode_init_once(&ei->vfs_inode);
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}
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static int __init init_inodecache(void)
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{
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efs_inode_cachep = kmem_cache_create("efs_inode_cache",
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sizeof(struct efs_inode_info), 0,
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SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD|
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SLAB_ACCOUNT, init_once);
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if (efs_inode_cachep == NULL)
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return -ENOMEM;
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return 0;
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}
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static void destroy_inodecache(void)
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{
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/*
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* Make sure all delayed rcu free inodes are flushed before we
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* destroy cache.
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*/
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rcu_barrier();
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kmem_cache_destroy(efs_inode_cachep);
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}
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static int efs_remount(struct super_block *sb, int *flags, char *data)
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{
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sync_filesystem(sb);
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*flags |= SB_RDONLY;
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return 0;
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}
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static const struct super_operations efs_superblock_operations = {
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.alloc_inode = efs_alloc_inode,
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.free_inode = efs_free_inode,
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.statfs = efs_statfs,
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.remount_fs = efs_remount,
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};
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static const struct export_operations efs_export_ops = {
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.fh_to_dentry = efs_fh_to_dentry,
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.fh_to_parent = efs_fh_to_parent,
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.get_parent = efs_get_parent,
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};
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static int __init init_efs_fs(void) {
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int err;
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pr_info(EFS_VERSION" - http://aeschi.ch.eu.org/efs/\n");
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err = init_inodecache();
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if (err)
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goto out1;
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err = register_filesystem(&efs_fs_type);
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if (err)
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goto out;
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return 0;
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out:
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destroy_inodecache();
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out1:
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return err;
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}
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static void __exit exit_efs_fs(void) {
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unregister_filesystem(&efs_fs_type);
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destroy_inodecache();
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}
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module_init(init_efs_fs)
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module_exit(exit_efs_fs)
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static efs_block_t efs_validate_vh(struct volume_header *vh) {
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int i;
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__be32 cs, *ui;
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int csum;
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efs_block_t sblock = 0; /* shuts up gcc */
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struct pt_types *pt_entry;
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int pt_type, slice = -1;
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if (be32_to_cpu(vh->vh_magic) != VHMAGIC) {
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/*
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* assume that we're dealing with a partition and allow
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* read_super() to try and detect a valid superblock
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* on the next block.
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*/
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return 0;
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}
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ui = ((__be32 *) (vh + 1)) - 1;
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for(csum = 0; ui >= ((__be32 *) vh);) {
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cs = *ui--;
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csum += be32_to_cpu(cs);
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}
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if (csum) {
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pr_warn("SGI disklabel: checksum bad, label corrupted\n");
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return 0;
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}
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#ifdef DEBUG
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pr_debug("bf: \"%16s\"\n", vh->vh_bootfile);
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for(i = 0; i < NVDIR; i++) {
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int j;
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char name[VDNAMESIZE+1];
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for(j = 0; j < VDNAMESIZE; j++) {
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name[j] = vh->vh_vd[i].vd_name[j];
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}
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name[j] = (char) 0;
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if (name[0]) {
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pr_debug("vh: %8s block: 0x%08x size: 0x%08x\n",
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name, (int) be32_to_cpu(vh->vh_vd[i].vd_lbn),
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(int) be32_to_cpu(vh->vh_vd[i].vd_nbytes));
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}
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}
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#endif
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for(i = 0; i < NPARTAB; i++) {
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pt_type = (int) be32_to_cpu(vh->vh_pt[i].pt_type);
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for(pt_entry = sgi_pt_types; pt_entry->pt_name; pt_entry++) {
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if (pt_type == pt_entry->pt_type) break;
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}
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#ifdef DEBUG
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if (be32_to_cpu(vh->vh_pt[i].pt_nblks)) {
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pr_debug("pt %2d: start: %08d size: %08d type: 0x%02x (%s)\n",
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i, (int)be32_to_cpu(vh->vh_pt[i].pt_firstlbn),
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(int)be32_to_cpu(vh->vh_pt[i].pt_nblks),
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pt_type, (pt_entry->pt_name) ?
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pt_entry->pt_name : "unknown");
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}
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#endif
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if (IS_EFS(pt_type)) {
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sblock = be32_to_cpu(vh->vh_pt[i].pt_firstlbn);
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slice = i;
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}
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}
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if (slice == -1) {
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pr_notice("partition table contained no EFS partitions\n");
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#ifdef DEBUG
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} else {
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pr_info("using slice %d (type %s, offset 0x%x)\n", slice,
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(pt_entry->pt_name) ? pt_entry->pt_name : "unknown",
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sblock);
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#endif
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}
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return sblock;
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}
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static int efs_validate_super(struct efs_sb_info *sb, struct efs_super *super) {
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if (!IS_EFS_MAGIC(be32_to_cpu(super->fs_magic)))
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return -1;
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sb->fs_magic = be32_to_cpu(super->fs_magic);
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sb->total_blocks = be32_to_cpu(super->fs_size);
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sb->first_block = be32_to_cpu(super->fs_firstcg);
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sb->group_size = be32_to_cpu(super->fs_cgfsize);
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sb->data_free = be32_to_cpu(super->fs_tfree);
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sb->inode_free = be32_to_cpu(super->fs_tinode);
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sb->inode_blocks = be16_to_cpu(super->fs_cgisize);
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sb->total_groups = be16_to_cpu(super->fs_ncg);
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return 0;
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}
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static int efs_fill_super(struct super_block *s, void *d, int silent)
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{
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struct efs_sb_info *sb;
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struct buffer_head *bh;
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struct inode *root;
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sb = kzalloc(sizeof(struct efs_sb_info), GFP_KERNEL);
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if (!sb)
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return -ENOMEM;
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s->s_fs_info = sb;
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s->s_time_min = 0;
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s->s_time_max = U32_MAX;
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s->s_magic = EFS_SUPER_MAGIC;
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if (!sb_set_blocksize(s, EFS_BLOCKSIZE)) {
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pr_err("device does not support %d byte blocks\n",
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EFS_BLOCKSIZE);
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return -EINVAL;
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}
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/* read the vh (volume header) block */
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bh = sb_bread(s, 0);
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if (!bh) {
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pr_err("cannot read volume header\n");
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return -EIO;
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}
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/*
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* if this returns zero then we didn't find any partition table.
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* this isn't (yet) an error - just assume for the moment that
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* the device is valid and go on to search for a superblock.
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*/
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sb->fs_start = efs_validate_vh((struct volume_header *) bh->b_data);
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brelse(bh);
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if (sb->fs_start == -1) {
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return -EINVAL;
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}
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bh = sb_bread(s, sb->fs_start + EFS_SUPER);
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if (!bh) {
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pr_err("cannot read superblock\n");
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return -EIO;
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}
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if (efs_validate_super(sb, (struct efs_super *) bh->b_data)) {
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#ifdef DEBUG
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pr_warn("invalid superblock at block %u\n",
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sb->fs_start + EFS_SUPER);
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#endif
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brelse(bh);
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return -EINVAL;
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}
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brelse(bh);
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if (!sb_rdonly(s)) {
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#ifdef DEBUG
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pr_info("forcing read-only mode\n");
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#endif
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s->s_flags |= SB_RDONLY;
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}
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s->s_op = &efs_superblock_operations;
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s->s_export_op = &efs_export_ops;
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root = efs_iget(s, EFS_ROOTINODE);
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if (IS_ERR(root)) {
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pr_err("get root inode failed\n");
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return PTR_ERR(root);
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}
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s->s_root = d_make_root(root);
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if (!(s->s_root)) {
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pr_err("get root dentry failed\n");
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return -ENOMEM;
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}
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return 0;
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}
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static int efs_statfs(struct dentry *dentry, struct kstatfs *buf) {
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struct super_block *sb = dentry->d_sb;
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struct efs_sb_info *sbi = SUPER_INFO(sb);
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u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
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buf->f_type = EFS_SUPER_MAGIC; /* efs magic number */
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buf->f_bsize = EFS_BLOCKSIZE; /* blocksize */
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buf->f_blocks = sbi->total_groups * /* total data blocks */
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(sbi->group_size - sbi->inode_blocks);
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buf->f_bfree = sbi->data_free; /* free data blocks */
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buf->f_bavail = sbi->data_free; /* free blocks for non-root */
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buf->f_files = sbi->total_groups * /* total inodes */
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sbi->inode_blocks *
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(EFS_BLOCKSIZE / sizeof(struct efs_dinode));
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buf->f_ffree = sbi->inode_free; /* free inodes */
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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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buf->f_namelen = EFS_MAXNAMELEN; /* max filename length */
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return 0;
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}
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