inode.c

嵌入式系统设计与实验教材二源码linux内核移植与编译

	UFSD(("ENTER, ino %lu, fragment %u\n", inode->i_ino, fragment))
	if (fragment < 0)
		goto abort_negative;
	if (fragment >
	    ((UFS_NDADDR + uspi->s_apb + uspi->s_2apb + uspi->s_3apb)
	     << uspi->s_fpbshift))
		goto abort_too_big;

	err = 0;
	ptr = fragment;
	  
	/*
	 * ok, these macros clean the logic up a bit and make
	 * it much more readable:
	 */
#define GET_INODE_DATABLOCK(x) \
		ufs_inode_getfrag(inode, x, fragment, 1, &err, 0, &phys, &new)
#define GET_INODE_PTR(x) \
		ufs_inode_getfrag(inode, x, fragment, uspi->s_fpb, &err, 1, NULL, NULL)
#define GET_INDIRECT_DATABLOCK(x) \
		ufs_block_getfrag(inode, bh, x, fragment, sb->s_blocksize, \
				  &err, 0, &phys, &new);
#define GET_INDIRECT_PTR(x) \
		ufs_block_getfrag(inode, bh, x, fragment, sb->s_blocksize, \
				  &err, 1, NULL, NULL);

	if (ptr < UFS_NDIR_FRAGMENT) {
		bh = GET_INODE_DATABLOCK(ptr);
		goto out;
	}
	ptr -= UFS_NDIR_FRAGMENT;
	if (ptr < (1 << (uspi->s_apbshift + uspi->s_fpbshift))) {
		bh = GET_INODE_PTR(UFS_IND_FRAGMENT + (ptr >> uspi->s_apbshift));
		goto get_indirect;
	}
	ptr -= 1 << (uspi->s_apbshift + uspi->s_fpbshift);
	if (ptr < (1 << (uspi->s_2apbshift + uspi->s_fpbshift))) {
		bh = GET_INODE_PTR(UFS_DIND_FRAGMENT + (ptr >> uspi->s_2apbshift));
		goto get_double;
	}
	ptr -= 1 << (uspi->s_2apbshift + uspi->s_fpbshift);
	bh = GET_INODE_PTR(UFS_TIND_FRAGMENT + (ptr >> uspi->s_3apbshift));
	bh = GET_INDIRECT_PTR((ptr >> uspi->s_2apbshift) & uspi->s_apbmask);
get_double:
	bh = GET_INDIRECT_PTR((ptr >> uspi->s_apbshift) & uspi->s_apbmask);
get_indirect:
	bh = GET_INDIRECT_DATABLOCK(ptr & uspi->s_apbmask);

#undef GET_INODE_DATABLOCK
#undef GET_INODE_PTR
#undef GET_INDIRECT_DATABLOCK
#undef GET_INDIRECT_PTR

out:
	if (err)
		goto abort;
	bh_result->b_dev = inode->i_dev;
	bh_result->b_blocknr = phys;
	bh_result->b_state |= (1UL << BH_Mapped);
	if (new)
		bh_result->b_state |= (1UL << BH_New);
abort:
	unlock_kernel();
	return err;

abort_negative:
	ufs_warning(sb, "ufs_get_block", "block < 0");
	goto abort;

abort_too_big:
	ufs_warning(sb, "ufs_get_block", "block > big");
	goto abort;
}

struct buffer_head *ufs_getfrag(struct inode *inode, unsigned int fragment,
				int create, int *err)
{
	struct buffer_head dummy;
	int error;

	dummy.b_state = 0;
	dummy.b_blocknr = -1000;
	error = ufs_getfrag_block(inode, fragment, &dummy, create);
	*err = error;
	if (!error && buffer_mapped(&dummy)) {
		struct buffer_head *bh;
		bh = sb_getblk(inode->i_sb, dummy.b_blocknr);
		if (buffer_new(&dummy)) {
			memset(bh->b_data, 0, inode->i_sb->s_blocksize);
			mark_buffer_uptodate(bh, 1);
			mark_buffer_dirty(bh);
		}
		return bh;
	}
	return NULL;
}

struct buffer_head * ufs_bread (struct inode * inode, unsigned fragment,
	int create, int * err)
{
	struct buffer_head * bh;

	UFSD(("ENTER, ino %lu, fragment %u\n", inode->i_ino, fragment))
	bh = ufs_getfrag (inode, fragment, create, err);
	if (!bh || buffer_uptodate(bh)) 		
		return bh;
	ll_rw_block (READ, 1, &bh);
	wait_on_buffer (bh);
	if (buffer_uptodate(bh))
		return bh;
	brelse (bh);
	*err = -EIO;
	return NULL;
}

static int ufs_writepage(struct page *page)
{
	return block_write_full_page(page,ufs_getfrag_block);
}
static int ufs_readpage(struct file *file, struct page *page)
{
	return block_read_full_page(page,ufs_getfrag_block);
}
static int ufs_prepare_write(struct file *file, struct page *page, unsigned from, unsigned to)
{
	return block_prepare_write(page,from,to,ufs_getfrag_block);
}
static int ufs_bmap(struct address_space *mapping, long block)
{
	return generic_block_bmap(mapping,block,ufs_getfrag_block);
}
struct address_space_operations ufs_aops = {
	readpage: ufs_readpage,
	writepage: ufs_writepage,
	sync_page: block_sync_page,
	prepare_write: ufs_prepare_write,
	commit_write: generic_commit_write,
	bmap: ufs_bmap
};

void ufs_read_inode (struct inode * inode)
{
	struct super_block * sb;
	struct ufs_sb_private_info * uspi;
	struct ufs_inode * ufs_inode;	
	struct buffer_head * bh;
	unsigned i;
	unsigned flags;
	
	UFSD(("ENTER, ino %lu\n", inode->i_ino))
	
	sb = inode->i_sb;
	uspi = sb->u.ufs_sb.s_uspi;
	flags = sb->u.ufs_sb.s_flags;

	if (inode->i_ino < UFS_ROOTINO || 
	    inode->i_ino > (uspi->s_ncg * uspi->s_ipg)) {
		ufs_warning (sb, "ufs_read_inode", "bad inode number (%lu)\n", inode->i_ino);
		goto bad_inode;
	}
	
	bh = sb_bread(sb, uspi->s_sbbase + ufs_inotofsba(inode->i_ino));
	if (!bh) {
		ufs_warning (sb, "ufs_read_inode", "unable to read inode %lu\n", inode->i_ino);
		goto bad_inode;
	}
	ufs_inode = (struct ufs_inode *) (bh->b_data + sizeof(struct ufs_inode) * ufs_inotofsbo(inode->i_ino));

	/*
	 * Copy data to the in-core inode.
	 */
	inode->i_mode = fs16_to_cpu(sb, ufs_inode->ui_mode);
	inode->i_nlink = fs16_to_cpu(sb, ufs_inode->ui_nlink);
	if (inode->i_nlink == 0)
		ufs_error (sb, "ufs_read_inode", "inode %lu has zero nlink\n", inode->i_ino);
	
	/*
	 * Linux now has 32-bit uid and gid, so we can support EFT.
	 */
	inode->i_uid = ufs_get_inode_uid(sb, ufs_inode);
	inode->i_gid = ufs_get_inode_gid(sb, ufs_inode);

	inode->i_size = fs64_to_cpu(sb, ufs_inode->ui_size);
	inode->i_atime = fs32_to_cpu(sb, ufs_inode->ui_atime.tv_sec);
	inode->i_ctime = fs32_to_cpu(sb, ufs_inode->ui_ctime.tv_sec);
	inode->i_mtime = fs32_to_cpu(sb, ufs_inode->ui_mtime.tv_sec);
	inode->i_blocks = fs32_to_cpu(sb, ufs_inode->ui_blocks);
	inode->i_blksize = PAGE_SIZE;   /* This is the optimal IO size (for stat) */
	inode->i_version = ++event;

	inode->u.ufs_i.i_flags = fs32_to_cpu(sb, ufs_inode->ui_flags);
	inode->u.ufs_i.i_gen = fs32_to_cpu(sb, ufs_inode->ui_gen);
	inode->u.ufs_i.i_shadow = fs32_to_cpu(sb, ufs_inode->ui_u3.ui_sun.ui_shadow);
	inode->u.ufs_i.i_oeftflag = fs32_to_cpu(sb, ufs_inode->ui_u3.ui_sun.ui_oeftflag);
	inode->u.ufs_i.i_lastfrag = (inode->i_size + uspi->s_fsize - 1) >> uspi->s_fshift;
	
	if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode))
		;
	else if (inode->i_blocks) {
		for (i = 0; i < (UFS_NDADDR + UFS_NINDIR); i++)
			inode->u.ufs_i.i_u1.i_data[i] = ufs_inode->ui_u2.ui_addr.ui_db[i];
	}
	else {
		for (i = 0; i < (UFS_NDADDR + UFS_NINDIR) * 4; i++)
			inode->u.ufs_i.i_u1.i_symlink[i] = ufs_inode->ui_u2.ui_symlink[i];
	}


	if (S_ISREG(inode->i_mode)) {
		inode->i_op = &ufs_file_inode_operations;
		inode->i_fop = &ufs_file_operations;
		inode->i_mapping->a_ops = &ufs_aops;
	} else if (S_ISDIR(inode->i_mode)) {
		inode->i_op = &ufs_dir_inode_operations;
		inode->i_fop = &ufs_dir_operations;
	} else if (S_ISLNK(inode->i_mode)) {
		if (!inode->i_blocks)
			inode->i_op = &ufs_fast_symlink_inode_operations;
		else {
			inode->i_op = &page_symlink_inode_operations;
			inode->i_mapping->a_ops = &ufs_aops;
		}
	} else
		init_special_inode(inode, inode->i_mode,
			fs32_to_cpu(sb, ufs_inode->ui_u2.ui_addr.ui_db[0]));

	brelse (bh);

	UFSD(("EXIT\n"))
	return;

bad_inode:
	make_bad_inode(inode);
	return;
}

static int ufs_update_inode(struct inode * inode, int do_sync)
{
	struct super_block * sb;
	struct ufs_sb_private_info * uspi;
	struct buffer_head * bh;
	struct ufs_inode * ufs_inode;
	unsigned i;
	unsigned flags;

	UFSD(("ENTER, ino %lu\n", inode->i_ino))

	sb = inode->i_sb;
	uspi = sb->u.ufs_sb.s_uspi;
	flags = sb->u.ufs_sb.s_flags;

	if (inode->i_ino < UFS_ROOTINO || 
	    inode->i_ino > (uspi->s_ncg * uspi->s_ipg)) {
		ufs_warning (sb, "ufs_read_inode", "bad inode number (%lu)\n", inode->i_ino);
		return -1;
	}

	bh = sb_bread(sb, ufs_inotofsba(inode->i_ino));
	if (!bh) {
		ufs_warning (sb, "ufs_read_inode", "unable to read inode %lu\n", inode->i_ino);
		return -1;
	}
	ufs_inode = (struct ufs_inode *) (bh->b_data + ufs_inotofsbo(inode->i_ino) * sizeof(struct ufs_inode));

	ufs_inode->ui_mode = cpu_to_fs16(sb, inode->i_mode);
	ufs_inode->ui_nlink = cpu_to_fs16(sb, inode->i_nlink);

	ufs_set_inode_uid(sb, ufs_inode, inode->i_uid);
	ufs_set_inode_gid(sb, ufs_inode, inode->i_gid);
		
	ufs_inode->ui_size = cpu_to_fs64(sb, inode->i_size);
	ufs_inode->ui_atime.tv_sec = cpu_to_fs32(sb, inode->i_atime);
	ufs_inode->ui_atime.tv_usec = 0;
	ufs_inode->ui_ctime.tv_sec = cpu_to_fs32(sb, inode->i_ctime);
	ufs_inode->ui_ctime.tv_usec = 0;
	ufs_inode->ui_mtime.tv_sec = cpu_to_fs32(sb, inode->i_mtime);
	ufs_inode->ui_mtime.tv_usec = 0;
	ufs_inode->ui_blocks = cpu_to_fs32(sb, inode->i_blocks);
	ufs_inode->ui_flags = cpu_to_fs32(sb, inode->u.ufs_i.i_flags);
	ufs_inode->ui_gen = cpu_to_fs32(sb, inode->u.ufs_i.i_gen);

	if ((flags & UFS_UID_MASK) == UFS_UID_EFT) {
		ufs_inode->ui_u3.ui_sun.ui_shadow = cpu_to_fs32(sb, inode->u.ufs_i.i_shadow);
		ufs_inode->ui_u3.ui_sun.ui_oeftflag = cpu_to_fs32(sb, inode->u.ufs_i.i_oeftflag);
	}

	if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode))
		ufs_inode->ui_u2.ui_addr.ui_db[0] = cpu_to_fs32(sb, kdev_t_to_nr(inode->i_rdev));
	else if (inode->i_blocks) {
		for (i = 0; i < (UFS_NDADDR + UFS_NINDIR); i++)
			ufs_inode->ui_u2.ui_addr.ui_db[i] = inode->u.ufs_i.i_u1.i_data[i];
	}
	else {
		for (i = 0; i < (UFS_NDADDR + UFS_NINDIR) * 4; i++)
			ufs_inode->ui_u2.ui_symlink[i] = inode->u.ufs_i.i_u1.i_symlink[i];
	}

	if (!inode->i_nlink)
		memset (ufs_inode, 0, sizeof(struct ufs_inode));
		
	mark_buffer_dirty(bh);
	if (do_sync) {
		ll_rw_block (WRITE, 1, &bh);
		wait_on_buffer (bh);
	}
	brelse (bh);
	
	UFSD(("EXIT\n"))
	return 0;
}

void ufs_write_inode (struct inode * inode, int wait)
{
	lock_kernel();
	ufs_update_inode (inode, wait);
	unlock_kernel();
}

int ufs_sync_inode (struct inode *inode)
{
	return ufs_update_inode (inode, 1);
}

void ufs_delete_inode (struct inode * inode)
{
	/*inode->u.ufs_i.i_dtime = CURRENT_TIME;*/
	lock_kernel();
	mark_inode_dirty(inode);
	ufs_update_inode(inode, IS_SYNC(inode));
	inode->i_size = 0;
	if (inode->i_blocks)
		ufs_truncate (inode);
	ufs_free_inode (inode);
	unlock_kernel();
}