linux/fs/omfs/inode.c
Bob Copeland 9442e54f43 omfs: refuse to mount if bitmap pointer is obviously wrong
If the free space bitmap pointer is corrupted such that it lies outside
of the number of blocks in the filesystem, print a message and fail the
mount so the user can fix it offline.

Signed-off-by: Bob Copeland <me@bobcopeland.com>
2010-07-10 14:37:39 -04:00

578 lines
13 KiB
C

/*
* Optimized MPEG FS - inode and super operations.
* Copyright (C) 2006 Bob Copeland <me@bobcopeland.com>
* Released under GPL v2.
*/
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/fs.h>
#include <linux/vfs.h>
#include <linux/parser.h>
#include <linux/buffer_head.h>
#include <linux/vmalloc.h>
#include <linux/writeback.h>
#include <linux/crc-itu-t.h>
#include "omfs.h"
MODULE_AUTHOR("Bob Copeland <me@bobcopeland.com>");
MODULE_DESCRIPTION("OMFS (ReplayTV/Karma) Filesystem for Linux");
MODULE_LICENSE("GPL");
struct buffer_head *omfs_bread(struct super_block *sb, sector_t block)
{
struct omfs_sb_info *sbi = OMFS_SB(sb);
if (block >= sbi->s_num_blocks)
return NULL;
return sb_bread(sb, clus_to_blk(sbi, block));
}
struct inode *omfs_new_inode(struct inode *dir, int mode)
{
struct inode *inode;
u64 new_block;
int err;
int len;
struct omfs_sb_info *sbi = OMFS_SB(dir->i_sb);
inode = new_inode(dir->i_sb);
if (!inode)
return ERR_PTR(-ENOMEM);
err = omfs_allocate_range(dir->i_sb, sbi->s_mirrors, sbi->s_mirrors,
&new_block, &len);
if (err)
goto fail;
inode->i_ino = new_block;
inode_init_owner(inode, NULL, mode);
inode->i_mapping->a_ops = &omfs_aops;
inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
switch (mode & S_IFMT) {
case S_IFDIR:
inode->i_op = &omfs_dir_inops;
inode->i_fop = &omfs_dir_operations;
inode->i_size = sbi->s_sys_blocksize;
inc_nlink(inode);
break;
case S_IFREG:
inode->i_op = &omfs_file_inops;
inode->i_fop = &omfs_file_operations;
inode->i_size = 0;
break;
}
insert_inode_hash(inode);
mark_inode_dirty(inode);
return inode;
fail:
make_bad_inode(inode);
iput(inode);
return ERR_PTR(err);
}
/*
* Update the header checksums for a dirty inode based on its contents.
* Caller is expected to hold the buffer head underlying oi and mark it
* dirty.
*/
static void omfs_update_checksums(struct omfs_inode *oi)
{
int xor, i, ofs = 0, count;
u16 crc = 0;
unsigned char *ptr = (unsigned char *) oi;
count = be32_to_cpu(oi->i_head.h_body_size);
ofs = sizeof(struct omfs_header);
crc = crc_itu_t(crc, ptr + ofs, count);
oi->i_head.h_crc = cpu_to_be16(crc);
xor = ptr[0];
for (i = 1; i < OMFS_XOR_COUNT; i++)
xor ^= ptr[i];
oi->i_head.h_check_xor = xor;
}
static int __omfs_write_inode(struct inode *inode, int wait)
{
struct omfs_inode *oi;
struct omfs_sb_info *sbi = OMFS_SB(inode->i_sb);
struct buffer_head *bh, *bh2;
u64 ctime;
int i;
int ret = -EIO;
int sync_failed = 0;
/* get current inode since we may have written sibling ptrs etc. */
bh = omfs_bread(inode->i_sb, inode->i_ino);
if (!bh)
goto out;
oi = (struct omfs_inode *) bh->b_data;
oi->i_head.h_self = cpu_to_be64(inode->i_ino);
if (S_ISDIR(inode->i_mode))
oi->i_type = OMFS_DIR;
else if (S_ISREG(inode->i_mode))
oi->i_type = OMFS_FILE;
else {
printk(KERN_WARNING "omfs: unknown file type: %d\n",
inode->i_mode);
goto out_brelse;
}
oi->i_head.h_body_size = cpu_to_be32(sbi->s_sys_blocksize -
sizeof(struct omfs_header));
oi->i_head.h_version = 1;
oi->i_head.h_type = OMFS_INODE_NORMAL;
oi->i_head.h_magic = OMFS_IMAGIC;
oi->i_size = cpu_to_be64(inode->i_size);
ctime = inode->i_ctime.tv_sec * 1000LL +
((inode->i_ctime.tv_nsec + 999)/1000);
oi->i_ctime = cpu_to_be64(ctime);
omfs_update_checksums(oi);
mark_buffer_dirty(bh);
if (wait) {
sync_dirty_buffer(bh);
if (buffer_req(bh) && !buffer_uptodate(bh))
sync_failed = 1;
}
/* if mirroring writes, copy to next fsblock */
for (i = 1; i < sbi->s_mirrors; i++) {
bh2 = omfs_bread(inode->i_sb, inode->i_ino + i);
if (!bh2)
goto out_brelse;
memcpy(bh2->b_data, bh->b_data, bh->b_size);
mark_buffer_dirty(bh2);
if (wait) {
sync_dirty_buffer(bh2);
if (buffer_req(bh2) && !buffer_uptodate(bh2))
sync_failed = 1;
}
brelse(bh2);
}
ret = (sync_failed) ? -EIO : 0;
out_brelse:
brelse(bh);
out:
return ret;
}
static int omfs_write_inode(struct inode *inode, struct writeback_control *wbc)
{
return __omfs_write_inode(inode, wbc->sync_mode == WB_SYNC_ALL);
}
int omfs_sync_inode(struct inode *inode)
{
return __omfs_write_inode(inode, 1);
}
/*
* called when an entry is deleted, need to clear the bits in the
* bitmaps.
*/
static void omfs_delete_inode(struct inode *inode)
{
truncate_inode_pages(&inode->i_data, 0);
if (S_ISREG(inode->i_mode)) {
inode->i_size = 0;
omfs_shrink_inode(inode);
}
omfs_clear_range(inode->i_sb, inode->i_ino, 2);
clear_inode(inode);
}
struct inode *omfs_iget(struct super_block *sb, ino_t ino)
{
struct omfs_sb_info *sbi = OMFS_SB(sb);
struct omfs_inode *oi;
struct buffer_head *bh;
u64 ctime;
unsigned long nsecs;
struct inode *inode;
inode = iget_locked(sb, ino);
if (!inode)
return ERR_PTR(-ENOMEM);
if (!(inode->i_state & I_NEW))
return inode;
bh = omfs_bread(inode->i_sb, ino);
if (!bh)
goto iget_failed;
oi = (struct omfs_inode *)bh->b_data;
/* check self */
if (ino != be64_to_cpu(oi->i_head.h_self))
goto fail_bh;
inode->i_uid = sbi->s_uid;
inode->i_gid = sbi->s_gid;
ctime = be64_to_cpu(oi->i_ctime);
nsecs = do_div(ctime, 1000) * 1000L;
inode->i_atime.tv_sec = ctime;
inode->i_mtime.tv_sec = ctime;
inode->i_ctime.tv_sec = ctime;
inode->i_atime.tv_nsec = nsecs;
inode->i_mtime.tv_nsec = nsecs;
inode->i_ctime.tv_nsec = nsecs;
inode->i_mapping->a_ops = &omfs_aops;
switch (oi->i_type) {
case OMFS_DIR:
inode->i_mode = S_IFDIR | (S_IRWXUGO & ~sbi->s_dmask);
inode->i_op = &omfs_dir_inops;
inode->i_fop = &omfs_dir_operations;
inode->i_size = sbi->s_sys_blocksize;
inc_nlink(inode);
break;
case OMFS_FILE:
inode->i_mode = S_IFREG | (S_IRWXUGO & ~sbi->s_fmask);
inode->i_fop = &omfs_file_operations;
inode->i_size = be64_to_cpu(oi->i_size);
break;
}
brelse(bh);
unlock_new_inode(inode);
return inode;
fail_bh:
brelse(bh);
iget_failed:
iget_failed(inode);
return ERR_PTR(-EIO);
}
static void omfs_put_super(struct super_block *sb)
{
struct omfs_sb_info *sbi = OMFS_SB(sb);
kfree(sbi->s_imap);
kfree(sbi);
sb->s_fs_info = NULL;
}
static int omfs_statfs(struct dentry *dentry, struct kstatfs *buf)
{
struct super_block *s = dentry->d_sb;
struct omfs_sb_info *sbi = OMFS_SB(s);
u64 id = huge_encode_dev(s->s_bdev->bd_dev);
buf->f_type = OMFS_MAGIC;
buf->f_bsize = sbi->s_blocksize;
buf->f_blocks = sbi->s_num_blocks;
buf->f_files = sbi->s_num_blocks;
buf->f_namelen = OMFS_NAMELEN;
buf->f_fsid.val[0] = (u32)id;
buf->f_fsid.val[1] = (u32)(id >> 32);
buf->f_bfree = buf->f_bavail = buf->f_ffree =
omfs_count_free(s);
return 0;
}
static const struct super_operations omfs_sops = {
.write_inode = omfs_write_inode,
.delete_inode = omfs_delete_inode,
.put_super = omfs_put_super,
.statfs = omfs_statfs,
.show_options = generic_show_options,
};
/*
* For Rio Karma, there is an on-disk free bitmap whose location is
* stored in the root block. For ReplayTV, there is no such free bitmap
* so we have to walk the tree. Both inodes and file data are allocated
* from the same map. This array can be big (300k) so we allocate
* in units of the blocksize.
*/
static int omfs_get_imap(struct super_block *sb)
{
int bitmap_size;
int array_size;
int count;
struct omfs_sb_info *sbi = OMFS_SB(sb);
struct buffer_head *bh;
unsigned long **ptr;
sector_t block;
bitmap_size = DIV_ROUND_UP(sbi->s_num_blocks, 8);
array_size = DIV_ROUND_UP(bitmap_size, sb->s_blocksize);
if (sbi->s_bitmap_ino == ~0ULL)
goto out;
sbi->s_imap_size = array_size;
sbi->s_imap = kzalloc(array_size * sizeof(unsigned long *), GFP_KERNEL);
if (!sbi->s_imap)
goto nomem;
block = clus_to_blk(sbi, sbi->s_bitmap_ino);
if (block >= sbi->s_num_blocks)
goto nomem;
ptr = sbi->s_imap;
for (count = bitmap_size; count > 0; count -= sb->s_blocksize) {
bh = sb_bread(sb, block++);
if (!bh)
goto nomem_free;
*ptr = kmalloc(sb->s_blocksize, GFP_KERNEL);
if (!*ptr) {
brelse(bh);
goto nomem_free;
}
memcpy(*ptr, bh->b_data, sb->s_blocksize);
if (count < sb->s_blocksize)
memset((void *)*ptr + count, 0xff,
sb->s_blocksize - count);
brelse(bh);
ptr++;
}
out:
return 0;
nomem_free:
for (count = 0; count < array_size; count++)
kfree(sbi->s_imap[count]);
kfree(sbi->s_imap);
nomem:
sbi->s_imap = NULL;
sbi->s_imap_size = 0;
return -ENOMEM;
}
enum {
Opt_uid, Opt_gid, Opt_umask, Opt_dmask, Opt_fmask
};
static const match_table_t tokens = {
{Opt_uid, "uid=%u"},
{Opt_gid, "gid=%u"},
{Opt_umask, "umask=%o"},
{Opt_dmask, "dmask=%o"},
{Opt_fmask, "fmask=%o"},
};
static int parse_options(char *options, struct omfs_sb_info *sbi)
{
char *p;
substring_t args[MAX_OPT_ARGS];
int option;
if (!options)
return 1;
while ((p = strsep(&options, ",")) != NULL) {
int token;
if (!*p)
continue;
token = match_token(p, tokens, args);
switch (token) {
case Opt_uid:
if (match_int(&args[0], &option))
return 0;
sbi->s_uid = option;
break;
case Opt_gid:
if (match_int(&args[0], &option))
return 0;
sbi->s_gid = option;
break;
case Opt_umask:
if (match_octal(&args[0], &option))
return 0;
sbi->s_fmask = sbi->s_dmask = option;
break;
case Opt_dmask:
if (match_octal(&args[0], &option))
return 0;
sbi->s_dmask = option;
break;
case Opt_fmask:
if (match_octal(&args[0], &option))
return 0;
sbi->s_fmask = option;
break;
default:
return 0;
}
}
return 1;
}
static int omfs_fill_super(struct super_block *sb, void *data, int silent)
{
struct buffer_head *bh, *bh2;
struct omfs_super_block *omfs_sb;
struct omfs_root_block *omfs_rb;
struct omfs_sb_info *sbi;
struct inode *root;
int ret = -EINVAL;
save_mount_options(sb, (char *) data);
sbi = kzalloc(sizeof(struct omfs_sb_info), GFP_KERNEL);
if (!sbi)
return -ENOMEM;
sb->s_fs_info = sbi;
sbi->s_uid = current_uid();
sbi->s_gid = current_gid();
sbi->s_dmask = sbi->s_fmask = current_umask();
if (!parse_options((char *) data, sbi))
goto end;
sb->s_maxbytes = 0xffffffff;
sb_set_blocksize(sb, 0x200);
bh = sb_bread(sb, 0);
if (!bh)
goto end;
omfs_sb = (struct omfs_super_block *)bh->b_data;
if (omfs_sb->s_magic != cpu_to_be32(OMFS_MAGIC)) {
if (!silent)
printk(KERN_ERR "omfs: Invalid superblock (%x)\n",
omfs_sb->s_magic);
goto out_brelse_bh;
}
sb->s_magic = OMFS_MAGIC;
sbi->s_num_blocks = be64_to_cpu(omfs_sb->s_num_blocks);
sbi->s_blocksize = be32_to_cpu(omfs_sb->s_blocksize);
sbi->s_mirrors = be32_to_cpu(omfs_sb->s_mirrors);
sbi->s_root_ino = be64_to_cpu(omfs_sb->s_root_block);
sbi->s_sys_blocksize = be32_to_cpu(omfs_sb->s_sys_blocksize);
mutex_init(&sbi->s_bitmap_lock);
if (sbi->s_sys_blocksize > PAGE_SIZE) {
printk(KERN_ERR "omfs: sysblock size (%d) is out of range\n",
sbi->s_sys_blocksize);
goto out_brelse_bh;
}
if (sbi->s_blocksize < sbi->s_sys_blocksize ||
sbi->s_blocksize > OMFS_MAX_BLOCK_SIZE) {
printk(KERN_ERR "omfs: block size (%d) is out of range\n",
sbi->s_blocksize);
goto out_brelse_bh;
}
/*
* Use sys_blocksize as the fs block since it is smaller than a
* page while the fs blocksize can be larger.
*/
sb_set_blocksize(sb, sbi->s_sys_blocksize);
/*
* ...and the difference goes into a shift. sys_blocksize is always
* a power of two factor of blocksize.
*/
sbi->s_block_shift = get_bitmask_order(sbi->s_blocksize) -
get_bitmask_order(sbi->s_sys_blocksize);
bh2 = omfs_bread(sb, be64_to_cpu(omfs_sb->s_root_block));
if (!bh2)
goto out_brelse_bh;
omfs_rb = (struct omfs_root_block *)bh2->b_data;
sbi->s_bitmap_ino = be64_to_cpu(omfs_rb->r_bitmap);
sbi->s_clustersize = be32_to_cpu(omfs_rb->r_clustersize);
if (sbi->s_num_blocks != be64_to_cpu(omfs_rb->r_num_blocks)) {
printk(KERN_ERR "omfs: block count discrepancy between "
"super and root blocks (%llx, %llx)\n",
(unsigned long long)sbi->s_num_blocks,
(unsigned long long)be64_to_cpu(omfs_rb->r_num_blocks));
goto out_brelse_bh2;
}
if (sbi->s_bitmap_ino != ~0ULL &&
sbi->s_bitmap_ino > sbi->s_num_blocks) {
printk(KERN_ERR "omfs: free space bitmap location is corrupt "
"(%llx, total blocks %llx)\n",
(unsigned long long) sbi->s_bitmap_ino,
(unsigned long long) sbi->s_num_blocks);
goto out_brelse_bh2;
}
ret = omfs_get_imap(sb);
if (ret)
goto out_brelse_bh2;
sb->s_op = &omfs_sops;
root = omfs_iget(sb, be64_to_cpu(omfs_rb->r_root_dir));
if (IS_ERR(root)) {
ret = PTR_ERR(root);
goto out_brelse_bh2;
}
sb->s_root = d_alloc_root(root);
if (!sb->s_root) {
iput(root);
goto out_brelse_bh2;
}
printk(KERN_DEBUG "omfs: Mounted volume %s\n", omfs_rb->r_name);
ret = 0;
out_brelse_bh2:
brelse(bh2);
out_brelse_bh:
brelse(bh);
end:
if (ret)
kfree(sbi);
return ret;
}
static int omfs_get_sb(struct file_system_type *fs_type,
int flags, const char *dev_name,
void *data, struct vfsmount *m)
{
return get_sb_bdev(fs_type, flags, dev_name, data, omfs_fill_super, m);
}
static struct file_system_type omfs_fs_type = {
.owner = THIS_MODULE,
.name = "omfs",
.get_sb = omfs_get_sb,
.kill_sb = kill_block_super,
.fs_flags = FS_REQUIRES_DEV,
};
static int __init init_omfs_fs(void)
{
return register_filesystem(&omfs_fs_type);
}
static void __exit exit_omfs_fs(void)
{
unregister_filesystem(&omfs_fs_type);
}
module_init(init_omfs_fs);
module_exit(exit_omfs_fs);