Commit abccd00f authored by Hugo Mills's avatar Hugo Mills Committed by Josef Bacik
Browse files

btrfs: Fix 32/64-bit problem with BTRFS_SET_RECEIVED_SUBVOL ioctl 



The structure for BTRFS_SET_RECEIVED_IOCTL packs differently on 32-bit
and 64-bit systems. This means that it is impossible to use btrfs
receive on a system with a 64-bit kernel and 32-bit userspace, because
the structure size (and hence the ioctl number) is different.

This patch adds a compatibility structure and ioctl to deal with the
above case.

Signed-off-by: default avatarHugo Mills <hugo@carfax.org.uk>
Signed-off-by: default avatarJosef Bacik <jbacik@fb.com>
parent d86477b3

fs/btrfs/ioctl.c

+111 −12
Original line number Diff line number Diff line
@@ -59,6 +59,32 @@ 
#include "props.h"

#include "sysfs.h"



#ifdef CONFIG_64BIT

/* If we have a 32-bit userspace and 64-bit kernel, then the UAPI

 * structures are incorrect, as the timespec structure from userspace

 * is 4 bytes too small. We define these alternatives here to teach

 * the kernel about the 32-bit struct packing.

 */

struct btrfs_ioctl_timespec_32 {

	__u64 sec;

	__u32 nsec;

} __attribute__ ((__packed__));



struct btrfs_ioctl_received_subvol_args_32 {

	char	uuid[BTRFS_UUID_SIZE];	/* in */

	__u64	stransid;		/* in */

	__u64	rtransid;		/* out */

	struct btrfs_ioctl_timespec_32 stime; /* in */

	struct btrfs_ioctl_timespec_32 rtime; /* out */

	__u64	flags;			/* in */

	__u64	reserved[16];		/* in */

} __attribute__ ((__packed__));



#define BTRFS_IOC_SET_RECEIVED_SUBVOL_32 _IOWR(BTRFS_IOCTL_MAGIC, 37, \

				struct btrfs_ioctl_received_subvol_args_32)

#endif





static int btrfs_clone(struct inode *src, struct inode *inode,

		       u64 off, u64 olen, u64 olen_aligned, u64 destoff);
@@ -4375,10 +4401,9 @@ static long btrfs_ioctl_quota_rescan_wait(struct file *file, void __user *arg) 
	return btrfs_qgroup_wait_for_completion(root->fs_info);

}



static long btrfs_ioctl_set_received_subvol(struct file *file,

					    void __user *arg)

static long _btrfs_ioctl_set_received_subvol(struct file *file,

					    struct btrfs_ioctl_received_subvol_args *sa)

{

	struct btrfs_ioctl_received_subvol_args *sa = NULL;

	struct inode *inode = file_inode(file);

	struct btrfs_root *root = BTRFS_I(inode)->root;

	struct btrfs_root_item *root_item = &root->root_item;
@@ -4406,13 +4431,6 @@ static long btrfs_ioctl_set_received_subvol(struct file *file, 
		goto out;

	}



	sa = memdup_user(arg, sizeof(*sa));

	if (IS_ERR(sa)) {

		ret = PTR_ERR(sa);

		sa = NULL;

		goto out;

	}



	/*

	 * 1 - root item

	 * 2 - uuid items (received uuid + subvol uuid)
@@ -4466,14 +4484,91 @@ static long btrfs_ioctl_set_received_subvol(struct file *file, 
		goto out;

	}



out:

	up_write(&root->fs_info->subvol_sem);

	mnt_drop_write_file(file);

	return ret;

}



#ifdef CONFIG_64BIT

static long btrfs_ioctl_set_received_subvol_32(struct file *file,

						void __user *arg)

{

	struct btrfs_ioctl_received_subvol_args_32 *args32 = NULL;

	struct btrfs_ioctl_received_subvol_args *args64 = NULL;

	int ret = 0;



	args32 = memdup_user(arg, sizeof(*args32));

	if (IS_ERR(args32)) {

		ret = PTR_ERR(args32);

		args32 = NULL;

		goto out;

	}



	args64 = kmalloc(sizeof(*args64), GFP_NOFS);

	if (IS_ERR(args64)) {

		ret = PTR_ERR(args64);

		args64 = NULL;

		goto out;

	}



	memcpy(args64->uuid, args32->uuid, BTRFS_UUID_SIZE);

	args64->stransid = args32->stransid;

	args64->rtransid = args32->rtransid;

	args64->stime.sec = args32->stime.sec;

	args64->stime.nsec = args32->stime.nsec;

	args64->rtime.sec = args32->rtime.sec;

	args64->rtime.nsec = args32->rtime.nsec;

	args64->flags = args32->flags;



	ret = _btrfs_ioctl_set_received_subvol(file, args64);

	if (ret)

		goto out;



	memcpy(args32->uuid, args64->uuid, BTRFS_UUID_SIZE);

	args32->stransid = args64->stransid;

	args32->rtransid = args64->rtransid;

	args32->stime.sec = args64->stime.sec;

	args32->stime.nsec = args64->stime.nsec;

	args32->rtime.sec = args64->rtime.sec;

	args32->rtime.nsec = args64->rtime.nsec;

	args32->flags = args64->flags;



	ret = copy_to_user(arg, args32, sizeof(*args32));

	if (ret)

		ret = -EFAULT;



out:

	kfree(args32);

	kfree(args64);

	return ret;

}

#endif



static long btrfs_ioctl_set_received_subvol(struct file *file,

					    void __user *arg)

{

	struct btrfs_ioctl_received_subvol_args *sa = NULL;

	int ret = 0;



	sa = memdup_user(arg, sizeof(*sa));

	if (IS_ERR(sa)) {

		ret = PTR_ERR(sa);

		sa = NULL;

		goto out;

	}



	ret = _btrfs_ioctl_set_received_subvol(file, sa);



	if (ret)

		goto out;



	ret = copy_to_user(arg, sa, sizeof(*sa));

	if (ret)

		ret = -EFAULT;



out:

	kfree(sa);

	up_write(&root->fs_info->subvol_sem);

	mnt_drop_write_file(file);

	return ret;

}
@@ -4792,6 +4887,10 @@ long btrfs_ioctl(struct file *file, unsigned int 
		return btrfs_ioctl_balance_progress(root, argp);

	case BTRFS_IOC_SET_RECEIVED_SUBVOL:

		return btrfs_ioctl_set_received_subvol(file, argp);

#ifdef CONFIG_64BIT

	case BTRFS_IOC_SET_RECEIVED_SUBVOL_32:

		return btrfs_ioctl_set_received_subvol_32(file, argp);

#endif

	case BTRFS_IOC_SEND:

		return btrfs_ioctl_send(file, argp);

	case BTRFS_IOC_GET_DEV_STATS:

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