patch-2.2.11 linux/fs/efs/super.c

• Lines: 256
• Date: Mon Aug 9 12:04:41 1999
• Orig file: v2.2.10/linux/fs/efs/super.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.2.10/linux/fs/efs/super.c linux/fs/efs/super.c
@@ -0,0 +1,255 @@
+/*
+ * super.c
+ *
+ * Copyright (c) 1999 Al Smith
+ *
+ * Portions derived from work (c) 1995,1996 Christian Vogelgsang.
+ */
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/locks.h>
+#include <linux/efs_fs.h>
+#include <linux/efs_vh.h>
+#include <linux/efs_fs_sb.h>
+
+static struct file_system_type efs_fs_type = {
+	"efs",			/* filesystem name */
+	FS_REQUIRES_DEV,	/* fs_flags */
+	efs_read_super,		/* entry function pointer */
+	NULL 			/* next */
+};
+
+static struct super_operations efs_superblock_operations = {
+	efs_read_inode,	/* read_inode */
+	NULL,		/* write_inode */
+	NULL,		/* put_inode */
+	NULL,		/* delete_inode */
+	NULL,		/* notify_change */
+	efs_put_super,	/* put_super */
+	NULL,		/* write_super */
+	efs_statfs,	/* statfs */
+	NULL		/* remount */
+};
+
+__initfunc(int init_efs_fs(void)) {
+	return register_filesystem(&efs_fs_type);
+}
+
+#ifdef MODULE
+EXPORT_NO_SYMBOLS;
+
+int init_module(void) {
+	printk("EFS: "EFS_VERSION" - http://aeschi.ch.eu.org/efs/\n");
+	return init_efs_fs();
+}
+
+void cleanup_module(void) {
+	unregister_filesystem(&efs_fs_type);
+}
+#endif
+
+static efs_block_t efs_validate_vh(struct volume_header *vh) {
+	int		i;
+	unsigned int	cs, csum, *ui;
+	efs_block_t	sblock = 0; /* shuts up gcc */
+	struct pt_types	*pt_entry;
+	int		pt_type, slice = -1;
+
+	if (be32_to_cpu(vh->vh_magic) != VHMAGIC) {
+		/*
+		 * assume that we're dealing with a partition and allow
+		 * read_super() to try and detect a valid superblock
+		 * on the next block.
+		 */
+		return 0;
+	}
+
+	ui = ((unsigned int *) (vh + 1)) - 1;
+	for(csum = 0; ui >= ((unsigned int *) vh);) {
+		cs = *ui--;
+		csum += be32_to_cpu(cs);
+	}
+	if (csum) {
+		printk(KERN_INFO "EFS: SGI disklabel: checksum bad, label corrupted\n");
+		return 0;
+	}
+
+#ifdef DEBUG
+	printk(KERN_DEBUG "EFS: bf: \"%16s\"\n", vh->vh_bootfile);
+
+	for(i = 0; i < NVDIR; i++) {
+		int	j;
+		char	name[VDNAMESIZE+1];
+
+		for(j = 0; j < VDNAMESIZE; j++) {
+			name[j] = vh->vh_vd[i].vd_name[j];
+		}
+		name[j] = (char) 0;
+
+		if (name[0]) {
+			printk(KERN_DEBUG "EFS: vh: %8s block: 0x%08x size: 0x%08x\n",
+				name,
+				(int) be32_to_cpu(vh->vh_vd[i].vd_lbn),
+				(int) be32_to_cpu(vh->vh_vd[i].vd_nbytes));
+		}
+	}
+#endif
+
+	for(i = 0; i < NPARTAB; i++) {
+		pt_type = (int) be32_to_cpu(vh->vh_pt[i].pt_type);
+		for(pt_entry = sgi_pt_types; pt_entry->pt_name; pt_entry++) {
+			if (pt_type == pt_entry->pt_type) break;
+		}
+#ifdef DEBUG
+		if (be32_to_cpu(vh->vh_pt[i].pt_nblks)) {
+			printk(KERN_DEBUG "EFS: pt %2d: start: %08d size: %08d type: 0x%02x (%s)\n",
+				i,
+				(int) be32_to_cpu(vh->vh_pt[i].pt_firstlbn),
+				(int) be32_to_cpu(vh->vh_pt[i].pt_nblks),
+				pt_type,
+				(pt_entry->pt_name) ? pt_entry->pt_name : "unknown");
+		}
+#endif
+		if (IS_EFS(pt_type)) {
+			sblock = be32_to_cpu(vh->vh_pt[i].pt_firstlbn);
+			slice = i;
+		}
+	}
+
+	if (slice == -1) {
+		printk(KERN_NOTICE "EFS: partition table contained no EFS partitions\n");
+#ifdef DEBUG
+	} else {
+		printk(KERN_INFO "EFS: using slice %d (type %s, offset 0x%x)\n",
+			slice,
+			(pt_entry->pt_name) ? pt_entry->pt_name : "unknown",
+			sblock);
+#endif
+	}
+	return(sblock);
+}
+
+static int efs_validate_super(struct efs_sb_info *sb, struct efs_super *super) {
+
+	if (!IS_EFS_MAGIC(be32_to_cpu(super->fs_magic))) return -1;
+	if (!(super->fs_cgisize)) return -1;
+
+	sb->fs_magic     = be32_to_cpu(super->fs_magic);
+	sb->total_blocks = be32_to_cpu(super->fs_size);
+	sb->first_block  = be32_to_cpu(super->fs_firstcg);
+	sb->group_size   = be32_to_cpu(super->fs_cgfsize);
+	sb->data_free    = be32_to_cpu(super->fs_tfree);
+	sb->inode_free   = be32_to_cpu(super->fs_tinode);
+	sb->inode_blocks = be16_to_cpu(super->fs_cgisize);
+	sb->total_groups = be16_to_cpu(super->fs_ncg);
+    
+	return 0;    
+}
+
+struct super_block *efs_read_super(struct super_block *s, void *d, int silent) {
+	kdev_t dev = s->s_dev;
+	struct efs_sb_info *sb;
+	struct buffer_head *bh;
+
+	MOD_INC_USE_COUNT;
+	lock_super(s);
+  
+ 	sb = SUPER_INFO(s);
+
+	set_blocksize(dev, EFS_BLOCKSIZE);
+  
+	/* read the vh (volume header) block */
+	bh = bread(dev, 0, EFS_BLOCKSIZE);
+
+	if (!bh) {
+		printk(KERN_ERR "EFS: cannot read volume header\n");
+		goto out_no_fs_ul;
+	}
+
+	/*
+	 * if this returns zero then we didn't find any partition table.
+	 * this isn't (yet) an error - just assume for the moment that
+	 * the device is valid and go on to search for a superblock.
+	 */
+	sb->fs_start = efs_validate_vh((struct volume_header *) bh->b_data);
+	brelse(bh);
+
+	if (sb->fs_start == -1) {
+		goto out_no_fs_ul;
+	}
+
+	bh = bread(dev, sb->fs_start + EFS_SUPER, EFS_BLOCKSIZE);
+	if (!bh) {
+		printk(KERN_ERR "EFS: cannot read superblock\n");
+		goto out_no_fs_ul;
+	}
+		
+	if (efs_validate_super(sb, (struct efs_super *) bh->b_data)) {
+#ifdef DEBUG
+		printk(KERN_WARNING "EFS: invalid superblock at block %u\n", sb->fs_start + EFS_SUPER);
+#endif
+		brelse(bh);
+		goto out_no_fs_ul;
+	}
+	brelse(bh);
+ 
+	s->s_magic		= EFS_SUPER_MAGIC;
+	s->s_blocksize		= EFS_BLOCKSIZE;
+	s->s_blocksize_bits	= EFS_BLOCKSIZE_BITS;
+	if (!(s->s_flags & MS_RDONLY)) {
+#ifdef DEBUG
+		printk(KERN_INFO "EFS: forcing read-only mode\n");
+#endif
+		s->s_flags |= MS_RDONLY;
+	}
+	s->s_op   = &efs_superblock_operations;
+	s->s_dev  = dev;
+	s->s_root = d_alloc_root(iget(s, EFS_ROOTINODE), NULL);
+	unlock_super(s);
+ 
+	if (!(s->s_root)) {
+		printk(KERN_ERR "EFS: get root inode failed\n");
+		goto out_no_fs;
+	}
+
+	if (check_disk_change(s->s_dev)) {
+		printk(KERN_ERR "EFS: device changed\n");
+		goto out_no_fs;
+	}
+
+	return(s);
+
+out_no_fs_ul:
+	unlock_super(s);
+out_no_fs:
+	s->s_dev = 0;
+	MOD_DEC_USE_COUNT;
+	return(NULL);
+}
+
+void efs_put_super(struct super_block *s) {
+	MOD_DEC_USE_COUNT;
+}
+
+int efs_statfs(struct super_block *s, struct statfs *buf, int bufsiz) {
+	struct statfs ret;
+	struct efs_sb_info *sb = SUPER_INFO(s);
+
+	ret.f_type    = EFS_SUPER_MAGIC;	/* efs magic number */
+	ret.f_bsize   = EFS_BLOCKSIZE;		/* blocksize */
+	ret.f_blocks  = sb->total_groups *	/* total data blocks */
+			(sb->group_size - sb->inode_blocks);
+	ret.f_bfree   = sb->data_free;		/* free data blocks */
+	ret.f_bavail  = sb->data_free;		/* free blocks for non-root */
+	ret.f_files   = sb->total_groups *	/* total inodes */
+			sb->inode_blocks *
+			(EFS_BLOCKSIZE / sizeof(struct efs_dinode));
+	ret.f_ffree   = sb->inode_free;	/* free inodes */
+	ret.f_fsid.val[0] = (sb->fs_magic >> 16) & 0xffff; /* fs ID */
+	ret.f_fsid.val[1] =  sb->fs_magic        & 0xffff; /* fs ID */
+	ret.f_namelen = EFS_MAXNAMELEN;		/* max filename length */
+
+	return copy_to_user(buf, &ret, bufsiz) ? -EFAULT : 0;
+}
+