Commit 10b4bd6c authored by Darrick J. Wong's avatar Darrick J. Wong
Browse files

xfs: refactor locking and unlocking two inodes against userspace IO 



Refactor the two functions that we use to lock and unlock two inodes to
block userspace from initiating IO against a file, whether via system
calls or mmap activity.

Signed-off-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: default avatarBrian Foster <bfoster@redhat.com>
parent 451d34ee

fs/xfs/xfs_file.c

+1 −1
Original line number Diff line number Diff line
@@ -1065,7 +1065,7 @@ xfs_file_remap_range( 
	if (mp->m_flags & XFS_MOUNT_WSYNC)

		xfs_log_force_inode(dest);

out_unlock:

	xfs_reflink_remap_unlock(file_in, file_out);

	xfs_reflink_remap_unlock(src, dest);

	if (ret)

		trace_xfs_reflink_remap_range_error(dest, ret, _RET_IP_);

	return remapped > 0 ? remapped : ret;

fs/xfs/xfs_reflink.c

+32 −20
Original line number Diff line number Diff line
@@ -1284,24 +1284,42 @@ xfs_iolock_two_inodes_and_break_layout( 
	return 0;

}



/* Unlock both inodes after they've been prepped for a range clone. */

/*

 * Lock two files so that userspace cannot initiate I/O via file syscalls or

 * mmap activity.

 */

static int

xfs_reflink_remap_lock(

	struct xfs_inode	*ip1,

	struct xfs_inode	*ip2)

{

	int			ret;



	ret = xfs_iolock_two_inodes_and_break_layout(VFS_I(ip1), VFS_I(ip2));

	if (ret)

		return ret;

	if (ip1 == ip2)

		xfs_ilock(ip1, XFS_MMAPLOCK_EXCL);

	else

		xfs_lock_two_inodes(ip1, XFS_MMAPLOCK_EXCL,

				    ip2, XFS_MMAPLOCK_EXCL);

	return 0;

}



/* Unlock both files to allow IO and mmap activity. */

void

xfs_reflink_remap_unlock(

	struct file		*file_in,

	struct file		*file_out)

	struct xfs_inode	*ip1,

	struct xfs_inode	*ip2)

{

	struct inode		*inode_in = file_inode(file_in);

	struct xfs_inode	*src = XFS_I(inode_in);

	struct inode		*inode_out = file_inode(file_out);

	struct xfs_inode	*dest = XFS_I(inode_out);

	bool			same_inode = (inode_in == inode_out);

	bool			same_inode = (ip1 == ip2);



	xfs_iunlock(dest, XFS_MMAPLOCK_EXCL);

	xfs_iunlock(ip2, XFS_MMAPLOCK_EXCL);

	if (!same_inode)

		xfs_iunlock(src, XFS_MMAPLOCK_EXCL);

	inode_unlock(inode_out);

		xfs_iunlock(ip1, XFS_MMAPLOCK_EXCL);

	inode_unlock(VFS_I(ip2));

	if (!same_inode)

		inode_unlock(inode_in);

		inode_unlock(VFS_I(ip1));

}



/*
@@ -1366,18 +1384,12 @@ xfs_reflink_remap_prep( 
	struct xfs_inode	*src = XFS_I(inode_in);

	struct inode		*inode_out = file_inode(file_out);

	struct xfs_inode	*dest = XFS_I(inode_out);

	bool			same_inode = (inode_in == inode_out);

	int			ret;



	/* Lock both files against IO */

	ret = xfs_iolock_two_inodes_and_break_layout(inode_in, inode_out);

	ret = xfs_reflink_remap_lock(src, dest);

	if (ret)

		return ret;

	if (same_inode)

		xfs_ilock(src, XFS_MMAPLOCK_EXCL);

	else

		xfs_lock_two_inodes(src, XFS_MMAPLOCK_EXCL, dest,

				XFS_MMAPLOCK_EXCL);



	/* Check file eligibility and prepare for block sharing. */

	ret = -EINVAL;
@@ -1428,7 +1440,7 @@ xfs_reflink_remap_prep( 


	return 0;

out_unlock:

	xfs_reflink_remap_unlock(file_in, file_out);

	xfs_reflink_remap_unlock(src, dest);

	return ret;

}

fs/xfs/xfs_reflink.h

+1 −2
Original line number Diff line number Diff line
@@ -56,7 +56,6 @@ extern int xfs_reflink_remap_blocks(struct xfs_inode *src, loff_t pos_in, 
		loff_t *remapped);

extern int xfs_reflink_update_dest(struct xfs_inode *dest, xfs_off_t newlen,

		xfs_extlen_t cowextsize, unsigned int remap_flags);

extern void xfs_reflink_remap_unlock(struct file *file_in,

		struct file *file_out);

extern void xfs_reflink_remap_unlock(struct xfs_inode *ip1, struct xfs_inode *ip2);



#endif /* __XFS_REFLINK_H */