/* * linux/fs/sysv/inode.c * * minix/inode.c * Copyright (C) 1991, 1992 Linus Torvalds * * xenix/inode.c * Copyright (C) 1992 Doug Evans * * coh/inode.c * Copyright (C) 1993 Pascal Haible, Bruno Haible * * sysv/inode.c * Copyright (C) 1993 Paul B. Monday * * sysv/inode.c * Copyright (C) 1993 Bruno Haible * Copyright (C) 1997, 1998 Krzysztof G. Baranowski * * This file contains code for read/parsing the superblock. */ #include <linux/module.h> #include <linux/init.h> #include <linux/slab.h> #include <linux/buffer_head.h> #include "sysv.h" /* * The following functions try to recognize specific filesystems. * * We recognize: * - Xenix FS by its magic number. * - SystemV FS by its magic number. * - Coherent FS by its funny fname/fpack field. * - SCO AFS by s_nfree == 0xffff * - V7 FS has no distinguishing features. * * We discriminate among SystemV4 and SystemV2 FS by the assumption that * the time stamp is not < 01-01-1980. */ enum { JAN_1_1980 = (10*365 + 2) * 24 * 60 * 60 }; static void detected_xenix(struct sysv_sb_info *sbi) { struct buffer_head *bh1 = sbi->s_bh1; struct buffer_head *bh2 = sbi->s_bh2; struct xenix_super_block * sbd1; struct xenix_super_block * sbd2; if (bh1 != bh2) sbd1 = sbd2 = (struct xenix_super_block *) bh1->b_data; else { /* block size = 512, so bh1 != bh2 */ sbd1 = (struct xenix_super_block *) bh1->b_data; sbd2 = (struct xenix_super_block *) (bh2->b_data - 512); } sbi->s_link_max = XENIX_LINK_MAX; sbi->s_fic_size = XENIX_NICINOD; sbi->s_flc_size = XENIX_NICFREE; sbi->s_sbd1 = (char *)sbd1; sbi->s_sbd2 = (char *)sbd2; sbi->s_sb_fic_count = &sbd1->s_ninode; sbi->s_sb_fic_inodes = &sbd1->s_inode[0]; sbi->s_sb_total_free_inodes = &sbd2->s_tinode; sbi->s_bcache_count = &sbd1->s_nfree; sbi->s_bcache = &sbd1->s_free[0]; sbi->s_free_blocks = &sbd2->s_tfree; sbi->s_sb_time = &sbd2->s_time; sbi->s_firstdatazone = fs16_to_cpu(sbi, sbd1->s_isize); sbi->s_nzones = fs32_to_cpu(sbi, sbd1->s_fsize); } static void detected_sysv4(struct sysv_sb_info *sbi) { struct sysv4_super_block * sbd; struct buffer_head *bh1 = sbi->s_bh1; struct buffer_head *bh2 = sbi->s_bh2; if (bh1 == bh2) sbd = (struct sysv4_super_block *) (bh1->b_data + BLOCK_SIZE/2); else sbd = (struct sysv4_super_block *) bh2->b_data; sbi->s_link_max = SYSV_LINK_MAX; sbi->s_fic_size = SYSV_NICINOD; sbi->s_flc_size = SYSV_NICFREE; sbi->s_sbd1 = (char *)sbd; sbi->s_sbd2 = (char *)sbd; sbi->s_sb_fic_count = &sbd->s_ninode; sbi->s_sb_fic_inodes = &sbd->s_inode[0]; sbi->s_sb_total_free_inodes = &sbd->s_tinode; sbi->s_bcache_count = &sbd->s_nfree; sbi->s_bcache = &sbd->s_free[0]; sbi->s_free_blocks = &sbd->s_tfree; sbi->s_sb_time = &sbd->s_time; sbi->s_sb_state = &sbd->s_state; sbi->s_firstdatazone = fs16_to_cpu(sbi, sbd->s_isize); sbi->s_nzones = fs32_to_cpu(sbi, sbd->s_fsize); } static void detected_sysv2(struct sysv_sb_info *sbi) { struct sysv2_super_block *sbd; struct buffer_head *bh1 = sbi->s_bh1; struct buffer_head *bh2 = sbi->s_bh2; if (bh1 == bh2) sbd = (struct sysv2_super_block *) (bh1->b_data + BLOCK_SIZE/2); else sbd = (struct sysv2_super_block *) bh2->b_data; sbi->s_link_max = SYSV_LINK_MAX; sbi->s_fic_size = SYSV_NICINOD; sbi->s_flc_size = SYSV_NICFREE; sbi->s_sbd1 = (char *)sbd; sbi->s_sbd2 = (char *)sbd; sbi->s_sb_fic_count = &sbd->s_ninode; sbi->s_sb_fic_inodes = &sbd->s_inode[0]; sbi->s_sb_total_free_inodes = &sbd->s_tinode; sbi->s_bcache_count = &sbd->s_nfree; sbi->s_bcache = &sbd->s_free[0]; sbi->s_free_blocks = &sbd->s_tfree; sbi->s_sb_time = &sbd->s_time; sbi->s_sb_state = &sbd->s_state; sbi->s_firstdatazone = fs16_to_cpu(sbi, sbd->s_isize); sbi->s_nzones = fs32_to_cpu(sbi, sbd->s_fsize); } static void detected_coherent(struct sysv_sb_info *sbi) { struct coh_super_block * sbd; struct buffer_head *bh1 = sbi->s_bh1; sbd = (struct coh_super_block *) bh1->b_data; sbi->s_link_max = COH_LINK_MAX; sbi->s_fic_size = COH_NICINOD; sbi->s_flc_size = COH_NICFREE; sbi->s_sbd1 = (char *)sbd; sbi->s_sbd2 = (char *)sbd; sbi->s_sb_fic_count = &sbd->s_ninode; sbi->s_sb_fic_inodes = &sbd->s_inode[0]; sbi->s_sb_total_free_inodes = &sbd->s_tinode; sbi->s_bcache_count = &sbd->s_nfree; sbi->s_bcache = &sbd->s_free[0]; sbi->s_free_blocks = &sbd->s_tfree; sbi->s_sb_time = &sbd->s_time; sbi->s_firstdatazone = fs16_to_cpu(sbi, sbd->s_isize); sbi->s_nzones = fs32_to_cpu(sbi, sbd->s_fsize); } static void detected_v7(struct sysv_sb_info *sbi) { struct buffer_head *bh2 = sbi->s_bh2; struct v7_super_block *sbd = (struct v7_super_block *)bh2->b_data; sbi->s_link_max = V7_LINK_MAX; sbi->s_fic_size = V7_NICINOD; sbi->s_flc_size = V7_NICFREE; sbi->s_sbd1 = (char *)sbd; sbi->s_sbd2 = (char *)sbd; sbi->s_sb_fic_count = &sbd->s_ninode; sbi->s_sb_fic_inodes = &sbd->s_inode[0]; sbi->s_sb_total_free_inodes = &sbd->s_tinode; sbi->s_bcache_count = &sbd->s_nfree; sbi->s_bcache = &sbd->s_free[0]; sbi->s_free_blocks = &sbd->s_tfree; sbi->s_sb_time = &sbd->s_time; sbi->s_firstdatazone = fs16_to_cpu(sbi, sbd->s_isize); sbi->s_nzones = fs32_to_cpu(sbi, sbd->s_fsize); } static int detect_xenix(struct sysv_sb_info *sbi, struct buffer_head *bh) { struct xenix_super_block *sbd = (struct xenix_super_block *)bh->b_data; if (*(__le32 *)&sbd->s_magic == cpu_to_le32(0x2b5544)) sbi->s_bytesex = BYTESEX_LE; else if (*(__be32 *)&sbd->s_magic == cpu_to_be32(0x2b5544)) sbi->s_bytesex = BYTESEX_BE; else return 0; switch (fs32_to_cpu(sbi, sbd->s_type)) { case 1: sbi->s_type = FSTYPE_XENIX; return 1; case 2: sbi->s_type = FSTYPE_XENIX; return 2; default: return 0; } } static int detect_sysv(struct sysv_sb_info *sbi, struct buffer_head *bh) { struct super_block *sb = sbi->s_sb; /* All relevant fields are at the same offsets in R2 and R4 */ struct sysv4_super_block * sbd; u32 type; sbd = (struct sysv4_super_block *) (bh->b_data + BLOCK_SIZE/2); if (*(__le32 *)&sbd->s_magic == cpu_to_le32(0xfd187e20)) sbi->s_bytesex = BYTESEX_LE; else if (*(__be32 *)&sbd->s_magic == cpu_to_be32(0xfd187e20)) sbi->s_bytesex = BYTESEX_BE; else return 0; type = fs32_to_cpu(sbi, sbd->s_type); if (fs16_to_cpu(sbi, sbd->s_nfree) == 0xffff) { sbi->s_type = FSTYPE_AFS; sbi->s_forced_ro = 1; if (!(sb->s_flags & MS_RDONLY)) { printk("SysV FS: SCO EAFS on %s detected, " "forcing read-only mode.\n", sb->s_id); } return type; } if (fs32_to_cpu(sbi, sbd->s_time) < JAN_1_1980) { /* this is likely to happen on SystemV2 FS */ if (type > 3 || type < 1) return 0; sbi->s_type = FSTYPE_SYSV2; return type; } if ((type > 3 || type < 1) && (type > 0x30 || type < 0x10)) return 0; /* On Interactive Unix (ISC) Version 4.0/3.x s_type field = 0x10, 0x20 or 0x30 indicates that symbolic links and the 14-character filename limit is gone. Due to lack of information about this feature read-only mode seems to be a reasonable approach... -KGB */ if (type >= 0x10) { printk("SysV FS: can't handle long file names on %s, " "forcing read-only mode.\n", sb->s_id); sbi->s_forced_ro = 1; } sbi->s_type = FSTYPE_SYSV4; return type >= 0x10 ? type >> 4 : type; } static int detect_coherent(struct sysv_sb_info *sbi, struct buffer_head *bh) { struct coh_super_block * sbd; sbd = (struct coh_super_block *) (bh->b_data + BLOCK_SIZE/2); if ((memcmp(sbd->s_fname,"noname",6) && memcmp(sbd->s_fname,"xxxxx ",6)) || (memcmp(sbd->s_fpack,"nopack",6) && memcmp(sbd->s_fpack,"xxxxx\n",6))) return 0; sbi->s_bytesex = BYTESEX_PDP; sbi->s_type = FSTYPE_COH; return 1; } static int detect_sysv_odd(struct sysv_sb_info *sbi, struct buffer_head *bh) { int size = detect_sysv(sbi, bh); return size>2 ? 0 : size; } static struct { int block; int (*test)(struct sysv_sb_info *, struct buffer_head *); } flavours[] = { {1, detect_xenix}, {0, detect_sysv}, {0, detect_coherent}, {9, detect_sysv_odd}, {15,detect_sysv_odd}, {18,detect_sysv}, }; static char *flavour_names[] = { [FSTYPE_XENIX] = "Xenix", [FSTYPE_SYSV4] = "SystemV", [FSTYPE_SYSV2] = "SystemV Release 2", [FSTYPE_COH] = "Coherent", [FSTYPE_V7] = "V7", [FSTYPE_AFS] = "AFS", }; static void (*flavour_setup[])(struct sysv_sb_info *) = { [FSTYPE_XENIX] = detected_xenix, [FSTYPE_SYSV4] = detected_sysv4, [FSTYPE_SYSV2] = detected_sysv2, [FSTYPE_COH] = detected_coherent, [FSTYPE_V7] = detected_v7, [FSTYPE_AFS] = detected_sysv4, }; static int complete_read_super(struct super_block *sb, int silent, int size) { struct sysv_sb_info *sbi = SYSV_SB(sb); struct inode *root_inode; char *found = flavour_names[sbi->s_type]; u_char n_bits = size+8; int bsize = 1 << n_bits; int bsize_4 = bsize >> 2; sbi->s_firstinodezone = 2; flavour_setup[sbi->s_type](sbi); sbi->s_truncate = 1; sbi->s_ndatazones = sbi->s_nzones - sbi->s_firstdatazone; sbi->s_inodes_per_block = bsize >> 6; sbi->s_inodes_per_block_1 = (bsize >> 6)-1; sbi->s_inodes_per_block_bits = n_bits-6; sbi->s_ind_per_block = bsize_4; sbi->s_ind_per_block_2 = bsize_4*bsize_4; sbi->s_toobig_block = 10 + bsize_4 * (1 + bsize_4 * (1 + bsize_4)); sbi->s_ind_per_block_bits = n_bits-2; sbi->s_ninodes = (sbi->s_firstdatazone - sbi->s_firstinodezone) << sbi->s_inodes_per_block_bits; if (!silent) printk("VFS: Found a %s FS (block size = %ld) on device %s\n", found, sb->s_blocksize, sb->s_id); sb->s_magic = SYSV_MAGIC_BASE + sbi->s_type; /* set up enough so that it can read an inode */ sb->s_op = &sysv_sops; root_inode = sysv_iget(sb, SYSV_ROOT_INO); if (IS_ERR(root_inode)) { printk("SysV FS: get root inode failed\n"); return 0; } sb->s_root = d_alloc_root(root_inode); if (!sb->s_root) { iput(root_inode); printk("SysV FS: get root dentry failed\n"); return 0; } if (sbi->s_forced_ro) sb->s_flags |= MS_RDONLY; if (sbi->s_truncate) sb->s_root->d_op = &sysv_dentry_operations; sb->s_dirt = 1; return 1; } static int sysv_fill_super(struct super_block *sb, void *data, int silent) { struct buffer_head *bh1, *bh = NULL; struct sysv_sb_info *sbi; unsigned long blocknr; int size = 0, i; BUILD_BUG_ON(1024 != sizeof (struct xenix_super_block)); BUILD_BUG_ON(512 != sizeof (struct sysv4_super_block)); BUILD_BUG_ON(512 != sizeof (struct sysv2_super_block)); BUILD_BUG_ON(500 != sizeof (struct coh_super_block)); BUILD_BUG_ON(64 != sizeof (struct sysv_inode)); sbi = kzalloc(sizeof(struct sysv_sb_info), GFP_KERNEL); if (!sbi) return -ENOMEM; sbi->s_sb = sb; sbi->s_block_base = 0; sb->s_fs_info = sbi; sb_set_blocksize(sb, BLOCK_SIZE); for (i = 0; i < ARRAY_SIZE(flavours) && !size; i++) { brelse(bh); bh = sb_bread(sb, flavours[i].block); if (!bh) continue; size = flavours[i].test(SYSV_SB(sb), bh); } if (!size) goto Eunknown; switch (size) { case 1: blocknr = bh->b_blocknr << 1; brelse(bh); sb_set_blocksize(sb, 512); bh1 = sb_bread(sb, blocknr); bh = sb_bread(sb, blocknr + 1); break; case 2: bh1 = bh; break; case 3: blocknr = bh->b_blocknr >> 1; brelse(bh); sb_set_blocksize(sb, 2048); bh1 = bh = sb_bread(sb, blocknr); break; default: goto Ebadsize; } if (bh && bh1) { sbi->s_bh1 = bh1; sbi->s_bh2 = bh; if (complete_read_super(sb, silent, size)) return 0; } brelse(bh1); brelse(bh); sb_set_blocksize(sb, BLOCK_SIZE); printk("oldfs: cannot read superblock\n"); failed: kfree(sbi); return -EINVAL; Eunknown: brelse(bh); if (!silent) printk("VFS: unable to find oldfs superblock on device %s\n", sb->s_id); goto failed; Ebadsize: brelse(bh); if (!silent) printk("VFS: oldfs: unsupported block size (%dKb)\n", 1<<(size-2)); goto failed; } static int v7_fill_super(struct super_block *sb, void *data, int silent) { struct sysv_sb_info *sbi; struct buffer_head *bh, *bh2 = NULL; struct v7_super_block *v7sb; struct sysv_inode *v7i; if (440 != sizeof (struct v7_super_block)) panic("V7 FS: bad super-block size"); if (64 != sizeof (struct sysv_inode)) panic("sysv fs: bad i-node size"); sbi = kzalloc(sizeof(struct sysv_sb_info), GFP_KERNEL); if (!sbi) return -ENOMEM; sbi->s_sb = sb; sbi->s_block_base = 0; sbi->s_type = FSTYPE_V7; sbi->s_bytesex = BYTESEX_PDP; sb->s_fs_info = sbi; sb_set_blocksize(sb, 512); if ((bh = sb_bread(sb, 1)) == NULL) { if (!silent) printk("VFS: unable to read V7 FS superblock on " "device %s.\n", sb->s_id); goto failed; } /* plausibility check on superblock */ v7sb = (struct v7_super_block *) bh->b_data; if (fs16_to_cpu(sbi, v7sb->s_nfree) > V7_NICFREE || fs16_to_cpu(sbi, v7sb->s_ninode) > V7_NICINOD || fs32_to_cpu(sbi, v7sb->s_time) == 0) goto failed; /* plausibility check on root inode: it is a directory, with a nonzero size that is a multiple of 16 */ if ((bh2 = sb_bread(sb, 2)) == NULL) goto failed; v7i = (struct sysv_inode *)(bh2->b_data + 64); if ((fs16_to_cpu(sbi, v7i->i_mode) & ~0777) != S_IFDIR || (fs32_to_cpu(sbi, v7i->i_size) == 0) || (fs32_to_cpu(sbi, v7i->i_size) & 017) != 0) goto failed; brelse(bh2); bh2 = NULL; sbi->s_bh1 = bh; sbi->s_bh2 = bh; if (complete_read_super(sb, silent, 1)) return 0; failed: brelse(bh2); brelse(bh); kfree(sbi); return -EINVAL; } /* Every kernel module contains stuff like this. */ static int sysv_get_sb(struct file_system_type *fs_type, int flags, const char *dev_name, void *data, struct vfsmount *mnt) { return get_sb_bdev(fs_type, flags, dev_name, data, sysv_fill_super, mnt); } static int v7_get_sb(struct file_system_type *fs_type, int flags, const char *dev_name, void *data, struct vfsmount *mnt) { return get_sb_bdev(fs_type, flags, dev_name, data, v7_fill_super, mnt); } static struct file_system_type sysv_fs_type = { .owner = THIS_MODULE, .name = "sysv", .get_sb = sysv_get_sb, .kill_sb = kill_block_super, .fs_flags = FS_REQUIRES_DEV, }; static struct file_system_type v7_fs_type = { .owner = THIS_MODULE, .name = "v7", .get_sb = v7_get_sb, .kill_sb = kill_block_super, .fs_flags = FS_REQUIRES_DEV, }; static int __init init_sysv_fs(void) { int error; error = sysv_init_icache(); if (error) goto out; error = register_filesystem(&sysv_fs_type); if (error) goto destroy_icache; error = register_filesystem(&v7_fs_type); if (error) goto unregister; return 0; unregister: unregister_filesystem(&sysv_fs_type); destroy_icache: sysv_destroy_icache(); out: return error; } static void __exit exit_sysv_fs(void) { unregister_filesystem(&sysv_fs_type); unregister_filesystem(&v7_fs_type); sysv_destroy_icache(); } module_init(init_sysv_fs) module_exit(exit_sysv_fs) MODULE_LICENSE("GPL");