Commit d2c292d8 authored by Jan Kara's avatar Jan Kara
Browse files

xfs: Convert double locking of MMAPLOCK to use VFS helpers 



Convert places in XFS that take MMAPLOCK for two inodes to use helper
VFS provides for it (filemap_invalidate_down_write_two()). Note that
this changes lock ordering for MMAPLOCK from inode number based ordering
to pointer based ordering VFS generally uses.

CC: "Darrick J. Wong" <djwong@kernel.org>
Reviewed-by: default avatarDarrick J. Wong <djwong@kernel.org>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarJan Kara <jack@suse.cz>
parent 2433480a

fs/xfs/xfs_bmap_util.c

+8 −7
Original line number Diff line number Diff line
@@ -1626,7 +1626,6 @@ xfs_swap_extents( 
	struct xfs_bstat	*sbp = &sxp->sx_stat;

	int			src_log_flags, target_log_flags;

	int			error = 0;

	int			lock_flags;

	uint64_t		f;

	int			resblks = 0;

	unsigned int		flags = 0;
@@ -1638,8 +1637,8 @@ xfs_swap_extents( 
	 * do the rest of the checks.

	 */

	lock_two_nondirectories(VFS_I(ip), VFS_I(tip));

	lock_flags = XFS_MMAPLOCK_EXCL;

	xfs_lock_two_inodes(ip, XFS_MMAPLOCK_EXCL, tip, XFS_MMAPLOCK_EXCL);

	filemap_invalidate_lock_two(VFS_I(ip)->i_mapping,

				    VFS_I(tip)->i_mapping);



	/* Verify that both files have the same format */

	if ((VFS_I(ip)->i_mode & S_IFMT) != (VFS_I(tip)->i_mode & S_IFMT)) {
@@ -1711,7 +1710,6 @@ xfs_swap_extents( 
	 * or cancel will unlock the inodes from this point onwards.

	 */

	xfs_lock_two_inodes(ip, XFS_ILOCK_EXCL, tip, XFS_ILOCK_EXCL);

	lock_flags |= XFS_ILOCK_EXCL;

	xfs_trans_ijoin(tp, ip, 0);

	xfs_trans_ijoin(tp, tip, 0);
@@ -1830,13 +1828,16 @@ xfs_swap_extents( 
	trace_xfs_swap_extent_after(ip, 0);

	trace_xfs_swap_extent_after(tip, 1);



out_unlock_ilock:

	xfs_iunlock(ip, XFS_ILOCK_EXCL);

	xfs_iunlock(tip, XFS_ILOCK_EXCL);

out_unlock:

	xfs_iunlock(ip, lock_flags);

	xfs_iunlock(tip, lock_flags);

	filemap_invalidate_unlock_two(VFS_I(ip)->i_mapping,

				      VFS_I(tip)->i_mapping);

	unlock_two_nondirectories(VFS_I(ip), VFS_I(tip));

	return error;



out_trans_cancel:

	xfs_trans_cancel(tp);

	goto out_unlock;

	goto out_unlock_ilock;

}

fs/xfs/xfs_inode.c

+11 −26
Original line number Diff line number Diff line
@@ -552,12 +552,10 @@ xfs_lock_inodes( 
}



/*

 * xfs_lock_two_inodes() can only be used to lock one type of lock at a time -

 * the mmaplock or the ilock, but not more than one type at a time. If we lock

 * more than one at a time, lockdep will report false positives saying we have

 * violated locking orders.  The iolock must be double-locked separately since

 * we use i_rwsem for that.  We now support taking one lock EXCL and the other

 * SHARED.

 * xfs_lock_two_inodes() can only be used to lock ilock. The iolock and

 * mmaplock must be double-locked separately since we use i_rwsem and

 * invalidate_lock for that. We now support taking one lock EXCL and the

 * other SHARED.

 */

void

xfs_lock_two_inodes(
@@ -575,15 +573,8 @@ xfs_lock_two_inodes( 
	ASSERT(hweight32(ip1_mode) == 1);

	ASSERT(!(ip0_mode & (XFS_IOLOCK_SHARED|XFS_IOLOCK_EXCL)));

	ASSERT(!(ip1_mode & (XFS_IOLOCK_SHARED|XFS_IOLOCK_EXCL)));

	ASSERT(!(ip0_mode & (XFS_MMAPLOCK_SHARED|XFS_MMAPLOCK_EXCL)) ||

	       !(ip0_mode & (XFS_ILOCK_SHARED|XFS_ILOCK_EXCL)));

	ASSERT(!(ip1_mode & (XFS_MMAPLOCK_SHARED|XFS_MMAPLOCK_EXCL)) ||

	       !(ip1_mode & (XFS_ILOCK_SHARED|XFS_ILOCK_EXCL)));

	ASSERT(!(ip1_mode & (XFS_MMAPLOCK_SHARED|XFS_MMAPLOCK_EXCL)) ||

	       !(ip0_mode & (XFS_ILOCK_SHARED|XFS_ILOCK_EXCL)));

	ASSERT(!(ip0_mode & (XFS_MMAPLOCK_SHARED|XFS_MMAPLOCK_EXCL)) ||

	       !(ip1_mode & (XFS_ILOCK_SHARED|XFS_ILOCK_EXCL)));



	ASSERT(!(ip0_mode & (XFS_MMAPLOCK_SHARED|XFS_MMAPLOCK_EXCL)));

	ASSERT(!(ip1_mode & (XFS_MMAPLOCK_SHARED|XFS_MMAPLOCK_EXCL)));

	ASSERT(ip0->i_ino != ip1->i_ino);



	if (ip0->i_ino > ip1->i_ino) {
@@ -3748,11 +3739,8 @@ xfs_ilock2_io_mmap( 
	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);

	filemap_invalidate_lock_two(VFS_I(ip1)->i_mapping,

				    VFS_I(ip2)->i_mapping);

	return 0;

}
@@ -3762,12 +3750,9 @@ xfs_iunlock2_io_mmap( 
	struct xfs_inode	*ip1,

	struct xfs_inode	*ip2)

{

	bool			same_inode = (ip1 == ip2);



	xfs_iunlock(ip2, XFS_MMAPLOCK_EXCL);

	if (!same_inode)

		xfs_iunlock(ip1, XFS_MMAPLOCK_EXCL);

	filemap_invalidate_unlock_two(VFS_I(ip1)->i_mapping,

				      VFS_I(ip2)->i_mapping);

	inode_unlock(VFS_I(ip2));

	if (!same_inode)

	if (ip1 != ip2)

		inode_unlock(VFS_I(ip1));

}