Commit a051f71c authored by Matthew Garrett's avatar Matthew Garrett Committed by Al Viro
Browse files

hfsplus: add an ioctl to bless files 



Making an hfsplus partition bootable requires the ability to "bless" a
file by putting its inode number in the volume header. Doing this from
userspace on a mounted filesystem is impractical since the kernel will
write back the original values on unmount. Add an ioctl to allow userspace
to update the volume header information based on the target file.

Signed-off-by: default avatarMatthew Garrett <mjg@redhat.com>
Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 0347b6e9

Documentation/ioctl/ioctl-number.txt

+1 −0
Original line number Diff line number Diff line
@@ -218,6 +218,7 @@ Code Seq#(hex) Include File Comments 
'h'	00-7F				conflict! Charon filesystem

					<mailto:zapman@interlan.net>

'h'	00-1F	linux/hpet.h		conflict!

'h'	80-8F	fs/hfsplus/ioctl.c

'i'	00-3F	linux/i2o-dev.h		conflict!

'i'	0B-1F	linux/ipmi.h		conflict!

'i'	80-8F	linux/i8k.h

fs/hfsplus/hfsplus_fs.h

+5 −0
Original line number Diff line number Diff line
@@ -316,6 +316,11 @@ static inline unsigned short hfsplus_min_io_size(struct super_block *sb) 
#define HFSPLUS_IOC_EXT2_SETFLAGS	FS_IOC_SETFLAGS





/*

 * hfs+-specific ioctl for making the filesystem bootable

 */

#define HFSPLUS_IOC_BLESS _IO('h', 0x80)



/*

 * Functions in any *.c used in other files

 */

fs/hfsplus/ioctl.c

+34 −0
Original line number Diff line number Diff line
@@ -20,6 +20,38 @@ 
#include <asm/uaccess.h>

#include "hfsplus_fs.h"



/*

 * "Blessing" an HFS+ filesystem writes metadata to the superblock informing

 * the platform firmware which file to boot from

 */

static int hfsplus_ioctl_bless(struct file *file, int __user *user_flags)

{

	struct dentry *dentry = file->f_path.dentry;

	struct inode *inode = dentry->d_inode;

	struct hfsplus_sb_info *sbi = HFSPLUS_SB(inode->i_sb);

	struct hfsplus_vh *vh = sbi->s_vhdr;

	struct hfsplus_vh *bvh = sbi->s_backup_vhdr;



	if (!capable(CAP_SYS_ADMIN))

		return -EPERM;



	mutex_lock(&sbi->vh_mutex);



	/* Directory containing the bootable system */

	vh->finder_info[0] = bvh->finder_info[0] =

		cpu_to_be32(parent_ino(dentry));



	/* Bootloader */

	vh->finder_info[1] = bvh->finder_info[1] = cpu_to_be32(inode->i_ino);



	/* Per spec, the OS X system folder - same as finder_info[0] here */

	vh->finder_info[5] = bvh->finder_info[5] =

		cpu_to_be32(parent_ino(dentry));



	mutex_unlock(&sbi->vh_mutex);

	return 0;

}



static int hfsplus_ioctl_getflags(struct file *file, int __user *user_flags)

{

	struct inode *inode = file->f_path.dentry->d_inode;
@@ -108,6 +140,8 @@ long hfsplus_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 
		return hfsplus_ioctl_getflags(file, argp);

	case HFSPLUS_IOC_EXT2_SETFLAGS:

		return hfsplus_ioctl_setflags(file, argp);

	case HFSPLUS_IOC_BLESS:

		return hfsplus_ioctl_bless(file, argp);

	default:

		return -ENOTTY;

	}

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