Commit acfbac77 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Carlos Maiolino
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xfs: take XFS_MMAPLOCK_EXCL xfs_file_write_zero_eof 



xfs_file_write_zero_eof is the only caller of xfs_zero_range that does
not take XFS_MMAPLOCK_EXCL (aka the invalidate lock).  Currently that
is actually the right thing, as an error in the iomap zeroing code will
also take the invalidate_lock to clean up, but to fix that deadlock we
need a consistent locking pattern first.

The only extra thing that XFS_MMAPLOCK_EXCL will lock out are read
pagefaults, which isn't really needed here, but also not actively
harmful.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarDarrick J. Wong <djwong@kernel.org>
Signed-off-by: default avatarCarlos Maiolino <cem@kernel.org>
parent 3c399374

fs/xfs/xfs_file.c

+7 −1
Original line number Diff line number Diff line
@@ -364,6 +364,7 @@ xfs_file_write_zero_eof( 
{

	struct xfs_inode	*ip = XFS_I(iocb->ki_filp->f_mapping->host);

	loff_t			isize;

	int			error;



	/*

	 * We need to serialise against EOF updates that occur in IO completions
@@ -411,7 +412,12 @@ xfs_file_write_zero_eof( 
	}



	trace_xfs_zero_eof(ip, isize, iocb->ki_pos - isize);

	return xfs_zero_range(ip, isize, iocb->ki_pos - isize, NULL);



	xfs_ilock(ip, XFS_MMAPLOCK_EXCL);

	error = xfs_zero_range(ip, isize, iocb->ki_pos - isize, NULL);

	xfs_iunlock(ip, XFS_MMAPLOCK_EXCL);



	return error;

}



/*

fs/xfs/xfs_iomap.c

+2 −0
Original line number Diff line number Diff line
@@ -1449,6 +1449,8 @@ xfs_zero_range( 
{

	struct inode		*inode = VFS_I(ip);



	xfs_assert_ilocked(ip, XFS_IOLOCK_EXCL | XFS_MMAPLOCK_EXCL);



	if (IS_DAX(inode))

		return dax_zero_range(inode, pos, len, did_zero,

				      &xfs_dax_write_iomap_ops);