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Commit 721259bc authored by Lachlan McIlroy's avatar Lachlan McIlroy Committed by David Chatterton
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[XFS] Fix ABBA deadlock between i_mutex and iolock. Avoid calling 


__blockdev_direct_IO for the DIO_OWN_LOCKING case for direct I/O reads
since it drops and reacquires the i_mutex while holding the iolock and
this violates the locking order.

SGI-PV: 955696
SGI-Modid: xfs-linux-melb:xfs-kern:26898a

Signed-off-by: default avatarLachlan McIlroy <lachlan@sgi.com>
Signed-off-by: default avatarDavid Chatterton <chatz@sgi.com>
parent 4be536de

fs/xfs/linux-2.6/xfs_aops.c

+13 −5
Original line number Original line Diff line number Diff line
@@ -1390,11 +1390,19 @@ xfs_vm_direct_IO( 




	iocb->private = xfs_alloc_ioend(inode, IOMAP_UNWRITTEN);

	iocb->private = xfs_alloc_ioend(inode, IOMAP_UNWRITTEN);





	if (rw == WRITE) {

		ret = blockdev_direct_IO_own_locking(rw, iocb, inode,

		ret = blockdev_direct_IO_own_locking(rw, iocb, inode,

			iomap.iomap_target->bt_bdev,

			iomap.iomap_target->bt_bdev,

			iov, offset, nr_segs,

			iov, offset, nr_segs,

			xfs_get_blocks_direct,

			xfs_get_blocks_direct,

			xfs_end_io_direct);

			xfs_end_io_direct);

	} else {

		ret = blockdev_direct_IO_no_locking(rw, iocb, inode,

			iomap.iomap_target->bt_bdev,

			iov, offset, nr_segs,

			xfs_get_blocks_direct,

			xfs_end_io_direct);

	}





	if (unlikely(ret <= 0 && iocb->private))

	if (unlikely(ret <= 0 && iocb->private))

		xfs_destroy_ioend(iocb->private);

		xfs_destroy_ioend(iocb->private);

fs/xfs/linux-2.6/xfs_lrw.c

+6 −5
Original line number Original line Diff line number Diff line
@@ -264,7 +264,9 @@ xfs_read( 
					dmflags, &locktype);

					dmflags, &locktype);

		if (ret) {

		if (ret) {

			xfs_iunlock(ip, XFS_IOLOCK_SHARED);

			xfs_iunlock(ip, XFS_IOLOCK_SHARED);

			goto unlock_mutex;

			if (unlikely(ioflags & IO_ISDIRECT))

				mutex_unlock(&inode->i_mutex);

			return ret;

		}

		}

	}

	}
@@ -272,6 +274,9 @@ xfs_read( 
		bhv_vop_flushinval_pages(vp, ctooff(offtoct(*offset)),

		bhv_vop_flushinval_pages(vp, ctooff(offtoct(*offset)),

						-1, FI_REMAPF_LOCKED);

						-1, FI_REMAPF_LOCKED);





	if (unlikely(ioflags & IO_ISDIRECT))

		mutex_unlock(&inode->i_mutex);



	xfs_rw_enter_trace(XFS_READ_ENTER, &ip->i_iocore,

	xfs_rw_enter_trace(XFS_READ_ENTER, &ip->i_iocore,

				(void *)iovp, segs, *offset, ioflags);

				(void *)iovp, segs, *offset, ioflags);

	ret = __generic_file_aio_read(iocb, iovp, segs, offset);

	ret = __generic_file_aio_read(iocb, iovp, segs, offset);
@@ -281,10 +286,6 @@ xfs_read( 
		XFS_STATS_ADD(xs_read_bytes, ret);

		XFS_STATS_ADD(xs_read_bytes, ret);





	xfs_iunlock(ip, XFS_IOLOCK_SHARED);

	xfs_iunlock(ip, XFS_IOLOCK_SHARED);



unlock_mutex:

	if (unlikely(ioflags & IO_ISDIRECT))

		mutex_unlock(&inode->i_mutex);

	return ret;

	return ret;

}

}