patch-2.4.6 linux/fs/sysv/super.c
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- Lines: 468
- Date:
Mon Jul 2 14:03:04 2001
- Orig file:
v2.4.5/linux/fs/sysv/super.c
- Orig date:
Wed Dec 31 16:00:00 1969
diff -u --recursive --new-file v2.4.5/linux/fs/sysv/super.c linux/fs/sysv/super.c
@@ -0,0 +1,467 @@
+/*
+ * 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/fs.h>
+#include <linux/sysv_fs.h>
+#include <linux/init.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.
+ * 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 super_block *sb)
+{
+ struct buffer_head *bh1 = sb->sv_bh1;
+ struct buffer_head *bh2 = sb->sv_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);
+ }
+
+ sb->sv_link_max = XENIX_LINK_MAX;
+ sb->sv_fic_size = XENIX_NICINOD;
+ sb->sv_flc_size = XENIX_NICFREE;
+ sb->sv_sbd1 = (char *) sbd1;
+ sb->sv_sbd2 = (char *) sbd2;
+ sb->sv_sb_fic_count = &sbd1->s_ninode;
+ sb->sv_sb_fic_inodes = &sbd1->s_inode[0];
+ sb->sv_sb_total_free_inodes = &sbd2->s_tinode;
+ sb->sv_bcache_count = &sbd1->s_nfree;
+ sb->sv_bcache = &sbd1->s_free[0];
+ sb->sv_free_blocks = &sbd2->s_tfree;
+ sb->sv_sb_time = &sbd2->s_time;
+ sb->sv_firstdatazone = fs16_to_cpu(sb, sbd1->s_isize);
+ sb->sv_nzones = fs32_to_cpu(sb, sbd1->s_fsize);
+}
+
+static void detected_sysv4(struct super_block *sb)
+{
+ struct sysv4_super_block * sbd;
+ struct buffer_head *bh1 = sb->sv_bh1;
+ struct buffer_head *bh2 = sb->sv_bh2;
+
+ if (bh1 == bh2)
+ sbd = (struct sysv4_super_block *) (bh1->b_data + BLOCK_SIZE/2);
+ else
+ sbd = (struct sysv4_super_block *) bh2->b_data;
+
+ sb->sv_link_max = SYSV_LINK_MAX;
+ sb->sv_fic_size = SYSV_NICINOD;
+ sb->sv_flc_size = SYSV_NICFREE;
+ sb->sv_sbd1 = (char *) sbd;
+ sb->sv_sbd2 = (char *) sbd;
+ sb->sv_sb_fic_count = &sbd->s_ninode;
+ sb->sv_sb_fic_inodes = &sbd->s_inode[0];
+ sb->sv_sb_total_free_inodes = &sbd->s_tinode;
+ sb->sv_bcache_count = &sbd->s_nfree;
+ sb->sv_bcache = &sbd->s_free[0];
+ sb->sv_free_blocks = &sbd->s_tfree;
+ sb->sv_sb_time = &sbd->s_time;
+ sb->sv_sb_state = &sbd->s_state;
+ sb->sv_firstdatazone = fs16_to_cpu(sb, sbd->s_isize);
+ sb->sv_nzones = fs32_to_cpu(sb, sbd->s_fsize);
+}
+
+static void detected_sysv2(struct super_block *sb)
+{
+ struct sysv2_super_block * sbd;
+ struct buffer_head *bh1 = sb->sv_bh1;
+ struct buffer_head *bh2 = sb->sv_bh2;
+
+ if (bh1 == bh2)
+ sbd = (struct sysv2_super_block *) (bh1->b_data + BLOCK_SIZE/2);
+ else
+ sbd = (struct sysv2_super_block *) bh2->b_data;
+
+ sb->sv_link_max = SYSV_LINK_MAX;
+ sb->sv_fic_size = SYSV_NICINOD;
+ sb->sv_flc_size = SYSV_NICFREE;
+ sb->sv_sbd1 = (char *) sbd;
+ sb->sv_sbd2 = (char *) sbd;
+ sb->sv_sb_fic_count = &sbd->s_ninode;
+ sb->sv_sb_fic_inodes = &sbd->s_inode[0];
+ sb->sv_sb_total_free_inodes = &sbd->s_tinode;
+ sb->sv_bcache_count = &sbd->s_nfree;
+ sb->sv_bcache = &sbd->s_free[0];
+ sb->sv_free_blocks = &sbd->s_tfree;
+ sb->sv_sb_time = &sbd->s_time;
+ sb->sv_sb_state = &sbd->s_state;
+ sb->sv_firstdatazone = fs16_to_cpu(sb, sbd->s_isize);
+ sb->sv_nzones = fs32_to_cpu(sb, sbd->s_fsize);
+}
+
+static void detected_coherent(struct super_block *sb)
+{
+ struct coh_super_block * sbd;
+ struct buffer_head *bh1 = sb->sv_bh1;
+
+ sbd = (struct coh_super_block *) bh1->b_data;
+
+ sb->sv_link_max = COH_LINK_MAX;
+ sb->sv_fic_size = COH_NICINOD;
+ sb->sv_flc_size = COH_NICFREE;
+ sb->sv_sbd1 = (char *) sbd;
+ sb->sv_sbd2 = (char *) sbd;
+ sb->sv_sb_fic_count = &sbd->s_ninode;
+ sb->sv_sb_fic_inodes = &sbd->s_inode[0];
+ sb->sv_sb_total_free_inodes = &sbd->s_tinode;
+ sb->sv_bcache_count = &sbd->s_nfree;
+ sb->sv_bcache = &sbd->s_free[0];
+ sb->sv_free_blocks = &sbd->s_tfree;
+ sb->sv_sb_time = &sbd->s_time;
+ sb->sv_firstdatazone = fs16_to_cpu(sb, sbd->s_isize);
+ sb->sv_nzones = fs32_to_cpu(sb, sbd->s_fsize);
+}
+
+static void detected_v7(struct super_block *sb)
+{
+ struct buffer_head *bh2 = sb->sv_bh2;
+ struct v7_super_block *sbd = (struct v7_super_block *)bh2->b_data;
+
+ sb->sv_link_max = V7_LINK_MAX;
+ sb->sv_fic_size = V7_NICINOD;
+ sb->sv_flc_size = V7_NICFREE;
+ sb->sv_sbd1 = (char *)sbd;
+ sb->sv_sbd2 = (char *)sbd;
+ sb->sv_sb_fic_count = &sbd->s_ninode;
+ sb->sv_sb_fic_inodes = &sbd->s_inode[0];
+ sb->sv_sb_total_free_inodes = &sbd->s_tinode;
+ sb->sv_bcache_count = &sbd->s_nfree;
+ sb->sv_bcache = &sbd->s_free[0];
+ sb->sv_free_blocks = &sbd->s_tfree;
+ sb->sv_sb_time = &sbd->s_time;
+ sb->sv_firstdatazone = fs16_to_cpu(sb, sbd->s_isize);
+ sb->sv_nzones = fs32_to_cpu(sb, sbd->s_fsize);
+}
+
+static int detect_xenix (struct super_block *sb, struct buffer_head *bh)
+{
+ struct xenix_super_block * sbd = (struct xenix_super_block *)bh->b_data;
+ if (sbd->s_magic == cpu_to_le32(0x2b5544))
+ sb->sv_bytesex = BYTESEX_LE;
+ else if (sbd->s_magic == cpu_to_be32(0x2b5544))
+ sb->sv_bytesex = BYTESEX_BE;
+ else
+ return 0;
+ if (sbd->s_type > 2 || sbd->s_type < 1)
+ return 0;
+ sb->sv_type = FSTYPE_XENIX;
+ return sbd->s_type;
+}
+
+static int detect_sysv (struct super_block *sb, struct buffer_head *bh)
+{
+ /* All relevant fields are at the same offsets in R2 and R4 */
+ struct sysv4_super_block * sbd;
+
+ sbd = (struct sysv4_super_block *) (bh->b_data + BLOCK_SIZE/2);
+ if (sbd->s_magic == cpu_to_le32(0xfd187e20))
+ sb->sv_bytesex = BYTESEX_LE;
+ else if (sbd->s_magic == cpu_to_be32(0xfd187e20))
+ sb->sv_bytesex = BYTESEX_BE;
+ else
+ return 0;
+ if (sbd->s_time < JAN_1_1980) {
+ /* this is likely to happen on SystemV2 FS */
+ if (sbd->s_type > 3 || sbd->s_type < 1)
+ return 0;
+ sb->sv_type = FSTYPE_SYSV2;
+ return sbd->s_type;
+ }
+ if ((sbd->s_type > 3 || sbd->s_type < 1) &&
+ (sbd->s_type > 0x30 || sbd->s_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 (sbd->s_type >= 0x10) {
+ printk("SysV FS: can't handle long file names on %s, "
+ "forcing read-only mode.\n", kdevname(sb->s_dev));
+ sb->s_flags |= MS_RDONLY;
+ }
+
+ sb->sv_type = FSTYPE_SYSV4;
+ return sbd->s_type >= 0x10 ? (sbd->s_type >> 4) : sbd->s_type;
+}
+
+static int detect_coherent (struct super_block *sb, 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;
+ sb->sv_bytesex = BYTESEX_PDP;
+ sb->sv_type = FSTYPE_COH;
+ return 1;
+}
+
+static int detect_sysv_odd(struct super_block *sb, struct buffer_head *bh)
+{
+ int size = detect_sysv(sb, bh);
+
+ return size>2 ? 0 : size;
+}
+
+static struct {
+ int block;
+ int (*test)(struct super_block *, 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",
+};
+
+static void (*flavour_setup[])(struct super_block *) = {
+ [FSTYPE_XENIX] detected_xenix,
+ [FSTYPE_SYSV4] detected_sysv4,
+ [FSTYPE_SYSV2] detected_sysv2,
+ [FSTYPE_COH] detected_coherent,
+ [FSTYPE_V7] detected_v7,
+};
+
+static int complete_read_super(struct super_block *sb, int silent, int size)
+{
+ struct inode *root_inode;
+ char *found = flavour_names[sb->sv_type];
+ u_char n_bits = size+8;
+ int bsize = 1 << n_bits;
+ int bsize_4 = bsize >> 2;
+
+ sb->sv_kludge_symlinks = 1;
+ sb->sv_firstinodezone = 2;
+
+ flavour_setup[sb->sv_type](sb);
+
+ sb->sv_truncate = 1;
+ sb->sv_ndatazones = sb->sv_nzones - sb->sv_firstdatazone;
+ sb->sv_inodes_per_block = bsize >> 6;
+ sb->sv_inodes_per_block_1 = (bsize >> 6)-1;
+ sb->sv_inodes_per_block_bits = n_bits-6;
+ sb->sv_ind_per_block = bsize_4;
+ sb->sv_ind_per_block_2 = bsize_4*bsize_4;
+ sb->sv_toobig_block = 10 + bsize_4 * (1 + bsize_4 * (1 + bsize_4));
+ sb->sv_ind_per_block_bits = n_bits-2;
+
+ sb->sv_ninodes = (sb->sv_firstdatazone - sb->sv_firstinodezone) << sb->sv_inodes_per_block_bits;
+
+ sb->s_blocksize = bsize;
+ sb->s_blocksize_bits = n_bits;
+ if (!silent)
+ printk("VFS: Found a %s FS (block size = %ld) on device %s\n",
+ found, sb->s_blocksize, bdevname(sb->s_dev));
+
+ sb->s_magic = SYSV_MAGIC_BASE + sb->sv_type;
+ /* set up enough so that it can read an inode */
+ sb->s_op = &sysv_sops;
+ root_inode = iget(sb,SYSV_ROOT_INO);
+ if (!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 (sb->sv_truncate)
+ sb->s_root->d_op = &sysv_dentry_operations;
+ sb->s_flags |= MS_RDONLY;
+ sb->s_dirt = 1;
+ return 1;
+}
+
+static struct super_block *sysv_read_super(struct super_block *sb,
+ void *data, int silent)
+{
+ struct buffer_head *bh1;
+ struct buffer_head *bh = NULL;
+ kdev_t dev = sb->s_dev;
+ unsigned long blocknr;
+ int size = 0;
+ int i;
+
+ if (1024 != sizeof (struct xenix_super_block))
+ panic("Xenix FS: bad super-block size");
+ if ((512 != sizeof (struct sysv4_super_block))
+ || (512 != sizeof (struct sysv2_super_block)))
+ panic("SystemV FS: bad super-block size");
+ if (500 != sizeof (struct coh_super_block))
+ panic("Coherent FS: bad super-block size");
+ if (64 != sizeof (struct sysv_inode))
+ panic("sysv fs: bad i-node size");
+ set_blocksize(dev,BLOCK_SIZE);
+ sb->sv_block_base = 0;
+
+ for (i = 0; i < sizeof(flavours)/sizeof(flavours[0]) && !size; i++) {
+ struct buffer_head *next_bh;
+ next_bh = bread(dev, flavours[i].block, BLOCK_SIZE);
+ if (!next_bh)
+ continue;
+ brelse(bh);
+ bh = next_bh;
+
+ size = flavours[i].test(sb, bh);
+ }
+
+ if (!size)
+ goto Eunknown;
+
+ switch (size) {
+ case 1:
+ blocknr = bh->b_blocknr << 1;
+ brelse(bh);
+ set_blocksize(dev, 512);
+ bh1 = bread(dev, blocknr, 512);
+ bh = bread(dev, blocknr + 1, 512);
+ break;
+ case 2:
+ bh1 = bh;
+ break;
+ case 3:
+ blocknr = bh->b_blocknr >> 1;
+ brelse(bh);
+ set_blocksize(dev, 2048);
+ bh1 = bh = bread(dev, blocknr, 2048);
+ break;
+ default:
+ goto Ebadsize;
+ }
+
+ if (bh && bh1) {
+ sb->sv_bh1 = bh1;
+ sb->sv_bh2 = bh;
+ if (complete_read_super(sb, silent, size))
+ return sb;
+ }
+
+ brelse(bh1);
+ brelse(bh);
+ set_blocksize(sb->s_dev,BLOCK_SIZE);
+ printk("oldfs: cannot read superblock\n");
+failed:
+ return NULL;
+
+Eunknown:
+ brelse(bh);
+ if (!silent)
+ printk("VFS: unable to find oldfs superblock on device %s\n",
+ bdevname(dev));
+ goto failed;
+Ebadsize:
+ brelse(bh);
+ if (!silent)
+ printk("VFS: oldfs: unsupported block size (%dKb)\n",
+ 1<<(size-2));
+ goto failed;
+}
+
+static struct super_block *v7_read_super(struct super_block *sb,void *data,
+ int silent)
+{
+ struct buffer_head *bh;
+ kdev_t dev = sb->s_dev;
+
+ 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");
+
+ sb->sv_type = FSTYPE_V7;
+ sb->sv_bytesex = BYTESEX_PDP;
+
+ set_blocksize(dev,512);
+
+ if ((bh = bread(dev, 1, 512)) == NULL) {
+ if (!silent)
+ printk("VFS: unable to read V7 FS superblock on device "
+ "%s.\n", bdevname(dev));
+ goto failed;
+ }
+
+
+ sb->sv_bh1 = bh;
+ sb->sv_bh2 = bh;
+ if (complete_read_super(sb, silent, 1))
+ return sb;
+
+ brelse(bh);
+failed:
+ return NULL;
+}
+
+/* Every kernel module contains stuff like this. */
+
+static DECLARE_FSTYPE_DEV(sysv_fs_type, "sysv", sysv_read_super);
+static DECLARE_FSTYPE_DEV(v7_fs_type, "v7", v7_read_super);
+
+static int __init init_sysv_fs(void)
+{
+ int err = register_filesystem(&sysv_fs_type);
+ if (!err)
+ err = register_filesystem(&v7_fs_type);
+ return err;
+}
+
+static void __exit exit_sysv_fs(void)
+{
+ unregister_filesystem(&sysv_fs_type);
+ unregister_filesystem(&v7_fs_type);
+}
+
+EXPORT_NO_SYMBOLS;
+
+module_init(init_sysv_fs)
+module_exit(exit_sysv_fs)
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