Commit 65523218 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Dave Chinner
Browse files

xfs: remove i_iolock and use i_rwsem in the VFS inode instead 



This patch drops the XFS-own i_iolock and uses the VFS i_rwsem which
recently replaced i_mutex instead.  This means we only have to take
one lock instead of two in many fast path operations, and we can
also shrink the xfs_inode structure.  Thanks to the xfs_ilock family
there is very little churn, the only thing of note is that we need
to switch to use the lock_two_directory helper for taking the i_rwsem
on two inodes in a few places to make sure our lock order matches
the one used in the VFS.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Tested-by: default avatarJens Axboe <axboe@fb.com>
Reviewed-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: default avatarDave Chinner <david@fromorbit.com>
parent f8319483

fs/xfs/xfs_aops.c

+2 −5
Original line number Diff line number Diff line
@@ -1585,7 +1585,6 @@ xfs_vm_bmap( 
	struct xfs_inode	*ip = XFS_I(inode);



	trace_xfs_vm_bmap(XFS_I(inode));

	xfs_ilock(ip, XFS_IOLOCK_SHARED);



	/*

	 * The swap code (ab-)uses ->bmap to get a block mapping and then
@@ -1593,12 +1592,10 @@ xfs_vm_bmap( 
	 * that on reflinks inodes, so we have to skip out here.  And yes,

	 * 0 is the magic code for a bmap error..

	 */

	if (xfs_is_reflink_inode(ip)) {

		xfs_iunlock(ip, XFS_IOLOCK_SHARED);

	if (xfs_is_reflink_inode(ip))

		return 0;

	}



	filemap_write_and_wait(mapping);

	xfs_iunlock(ip, XFS_IOLOCK_SHARED);

	return generic_block_bmap(mapping, block, xfs_get_blocks);

}

fs/xfs/xfs_bmap_util.c

+5 −7
Original line number Diff line number Diff line
@@ -1935,8 +1935,8 @@ xfs_swap_extents( 
	 * page cache safely. Once we have done this we can take the ilocks and

	 * do the rest of the checks.

	 */

	lock_flags = XFS_IOLOCK_EXCL | XFS_MMAPLOCK_EXCL;

	xfs_lock_two_inodes(ip, tip, XFS_IOLOCK_EXCL);

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

	lock_flags = XFS_MMAPLOCK_EXCL;

	xfs_lock_two_inodes(ip, tip, XFS_MMAPLOCK_EXCL);



	/* Verify that both files have the same format */
@@ -2076,15 +2076,13 @@ xfs_swap_extents( 
	trace_xfs_swap_extent_after(ip, 0);

	trace_xfs_swap_extent_after(tip, 1);



out_unlock:

	xfs_iunlock(ip, lock_flags);

	xfs_iunlock(tip, lock_flags);

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

	return error;



out_trans_cancel:

	xfs_trans_cancel(tp);



out_unlock:

	xfs_iunlock(ip, lock_flags);

	xfs_iunlock(tip, lock_flags);

	return error;

	goto out_unlock;

}

fs/xfs/xfs_dir2_readdir.c

+0 −2
Original line number Diff line number Diff line
@@ -677,7 +677,6 @@ xfs_readdir( 
	args.dp = dp;

	args.geo = dp->i_mount->m_dir_geo;



	xfs_ilock(dp, XFS_IOLOCK_SHARED);

	if (dp->i_d.di_format == XFS_DINODE_FMT_LOCAL)

		rval = xfs_dir2_sf_getdents(&args, ctx);

	else if ((rval = xfs_dir2_isblock(&args, &v)))
@@ -686,7 +685,6 @@ xfs_readdir( 
		rval = xfs_dir2_block_getdents(&args, ctx);

	else

		rval = xfs_dir2_leaf_getdents(&args, ctx, bufsize);

	xfs_iunlock(dp, XFS_IOLOCK_SHARED);



	return rval;

}

fs/xfs/xfs_file.c

+23 −56
Original line number Diff line number Diff line
@@ -47,40 +47,6 @@ 


static const struct vm_operations_struct xfs_file_vm_ops;



/*

 * Locking primitives for read and write IO paths to ensure we consistently use

 * and order the inode->i_mutex, ip->i_lock and ip->i_iolock.

 */

static inline void

xfs_rw_ilock(

	struct xfs_inode	*ip,

	int			type)

{

	if (type & XFS_IOLOCK_EXCL)

		inode_lock(VFS_I(ip));

	xfs_ilock(ip, type);

}



static inline void

xfs_rw_iunlock(

	struct xfs_inode	*ip,

	int			type)

{

	xfs_iunlock(ip, type);

	if (type & XFS_IOLOCK_EXCL)

		inode_unlock(VFS_I(ip));

}



static inline void

xfs_rw_ilock_demote(

	struct xfs_inode	*ip,

	int			type)

{

	xfs_ilock_demote(ip, type);

	if (type & XFS_IOLOCK_EXCL)

		inode_unlock(VFS_I(ip));

}



/*

 * Clear the specified ranges to zero through either the pagecache or DAX.

 * Holes and unwritten extents will be left as-is as they already are zeroed.
@@ -273,7 +239,7 @@ xfs_file_dio_aio_read( 


	file_accessed(iocb->ki_filp);



	xfs_rw_ilock(ip, XFS_IOLOCK_SHARED);

	xfs_ilock(ip, XFS_IOLOCK_SHARED);

	if (mapping->nrpages) {

		ret = filemap_write_and_wait_range(mapping, iocb->ki_pos, end);

		if (ret)
@@ -299,7 +265,7 @@ xfs_file_dio_aio_read( 
	}



out_unlock:

	xfs_rw_iunlock(ip, XFS_IOLOCK_SHARED);

	xfs_iunlock(ip, XFS_IOLOCK_SHARED);

	return ret;

}
@@ -317,9 +283,9 @@ xfs_file_dax_read( 
	if (!count)

		return 0; /* skip atime */



	xfs_rw_ilock(ip, XFS_IOLOCK_SHARED);

	xfs_ilock(ip, XFS_IOLOCK_SHARED);

	ret = dax_iomap_rw(iocb, to, &xfs_iomap_ops);

	xfs_rw_iunlock(ip, XFS_IOLOCK_SHARED);

	xfs_iunlock(ip, XFS_IOLOCK_SHARED);



	file_accessed(iocb->ki_filp);

	return ret;
@@ -335,9 +301,9 @@ xfs_file_buffered_aio_read( 


	trace_xfs_file_buffered_read(ip, iov_iter_count(to), iocb->ki_pos);



	xfs_rw_ilock(ip, XFS_IOLOCK_SHARED);

	xfs_ilock(ip, XFS_IOLOCK_SHARED);

	ret = generic_file_read_iter(iocb, to);

	xfs_rw_iunlock(ip, XFS_IOLOCK_SHARED);

	xfs_iunlock(ip, XFS_IOLOCK_SHARED);



	return ret;

}
@@ -418,15 +384,18 @@ restart: 
	if (error <= 0)

		return error;



	error = xfs_break_layouts(inode, iolock, true);

	error = xfs_break_layouts(inode, iolock);

	if (error)

		return error;



	/* For changing security info in file_remove_privs() we need i_mutex */

	/*

	 * For changing security info in file_remove_privs() we need i_rwsem

	 * exclusively.

	 */

	if (*iolock == XFS_IOLOCK_SHARED && !IS_NOSEC(inode)) {

		xfs_rw_iunlock(ip, *iolock);

		xfs_iunlock(ip, *iolock);

		*iolock = XFS_IOLOCK_EXCL;

		xfs_rw_ilock(ip, *iolock);

		xfs_ilock(ip, *iolock);

		goto restart;

	}

	/*
@@ -451,9 +420,9 @@ restart: 
		spin_unlock(&ip->i_flags_lock);

		if (!drained_dio) {

			if (*iolock == XFS_IOLOCK_SHARED) {

				xfs_rw_iunlock(ip, *iolock);

				xfs_iunlock(ip, *iolock);

				*iolock = XFS_IOLOCK_EXCL;

				xfs_rw_ilock(ip, *iolock);

				xfs_ilock(ip, *iolock);

				iov_iter_reexpand(from, count);

			}

			/*
@@ -559,7 +528,7 @@ xfs_file_dio_aio_write( 
		iolock = XFS_IOLOCK_SHARED;

	}



	xfs_rw_ilock(ip, iolock);

	xfs_ilock(ip, iolock);



	ret = xfs_file_aio_write_checks(iocb, from, &iolock);

	if (ret)
@@ -591,7 +560,7 @@ xfs_file_dio_aio_write( 
	if (unaligned_io)

		inode_dio_wait(inode);

	else if (iolock == XFS_IOLOCK_EXCL) {

		xfs_rw_ilock_demote(ip, XFS_IOLOCK_EXCL);

		xfs_ilock_demote(ip, XFS_IOLOCK_EXCL);

		iolock = XFS_IOLOCK_SHARED;

	}
@@ -621,7 +590,7 @@ xfs_file_dio_aio_write( 
		iov_iter_advance(from, ret);

	}

out:

	xfs_rw_iunlock(ip, iolock);

	xfs_iunlock(ip, iolock);



	/*

	 * No fallback to buffered IO on errors for XFS, direct IO will either
@@ -643,7 +612,7 @@ xfs_file_dax_write( 
	size_t			count;

	loff_t			pos;



	xfs_rw_ilock(ip, iolock);

	xfs_ilock(ip, iolock);

	ret = xfs_file_aio_write_checks(iocb, from, &iolock);

	if (ret)

		goto out;
@@ -652,15 +621,13 @@ xfs_file_dax_write( 
	count = iov_iter_count(from);



	trace_xfs_file_dax_write(ip, count, pos);



	ret = dax_iomap_rw(iocb, from, &xfs_iomap_ops);

	if (ret > 0 && iocb->ki_pos > i_size_read(inode)) {

		i_size_write(inode, iocb->ki_pos);

		error = xfs_setfilesize(ip, pos, ret);

	}



out:

	xfs_rw_iunlock(ip, iolock);

	xfs_iunlock(ip, iolock);

	return error ? error : ret;

}
@@ -677,7 +644,7 @@ xfs_file_buffered_aio_write( 
	int			enospc = 0;

	int			iolock = XFS_IOLOCK_EXCL;



	xfs_rw_ilock(ip, iolock);

	xfs_ilock(ip, iolock);



	ret = xfs_file_aio_write_checks(iocb, from, &iolock);

	if (ret)
@@ -721,7 +688,7 @@ write_retry: 


	current->backing_dev_info = NULL;

out:

	xfs_rw_iunlock(ip, iolock);

	xfs_iunlock(ip, iolock);

	return ret;

}
@@ -797,7 +764,7 @@ xfs_file_fallocate( 
		return -EOPNOTSUPP;



	xfs_ilock(ip, iolock);

	error = xfs_break_layouts(inode, &iolock, false);

	error = xfs_break_layouts(inode, &iolock);

	if (error)

		goto out_unlock;

fs/xfs/xfs_icache.c

+2 −4
Original line number Diff line number Diff line
@@ -70,8 +70,6 @@ xfs_inode_alloc( 
	ASSERT(!xfs_isiflocked(ip));

	ASSERT(ip->i_ino == 0);



	mrlock_init(&ip->i_iolock, MRLOCK_BARRIER, "xfsio", ip->i_ino);



	/* initialise the xfs inode */

	ip->i_ino = ino;

	ip->i_mount = mp;
@@ -394,8 +392,8 @@ xfs_iget_cache_hit( 
		xfs_inode_clear_reclaim_tag(pag, ip->i_ino);

		inode->i_state = I_NEW;



		ASSERT(!rwsem_is_locked(&ip->i_iolock.mr_lock));

		mrlock_init(&ip->i_iolock, MRLOCK_BARRIER, "xfsio", ip->i_ino);

		ASSERT(!rwsem_is_locked(&inode->i_rwsem));

		init_rwsem(&inode->i_rwsem);



		spin_unlock(&ip->i_flags_lock);

		spin_unlock(&pag->pag_ici_lock);

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