From: Darrick J. Wong Date: Mon, 18 Sep 2017 16:41:16 +0000 (-0700) Subject: xfs: don't unconditionally clear the reflink flag on zero-block files X-Git-Tag: v4.13.10~17 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=a58a0826656d3159fd0cd0d8be63a80edf4dae07;p=thirdparty%2Fkernel%2Fstable.git xfs: don't unconditionally clear the reflink flag on zero-block files commit cc6f77710a6de6210f9feda7cd53e2f5ee7a7e69 upstream. If we have speculative cow preallocations hanging around in the cow fork, don't let a truncate operation clear the reflink flag because if we do then there's a chance we'll forget to free those extents when we destroy the incore inode. Reported-by: Amir Goldstein Reviewed-by: Carlos Maiolino Reviewed-by: Christoph Hellwig Signed-off-by: Darrick J. Wong Signed-off-by: Greg Kroah-Hartman --- diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c index 97045e8dfed5f..cd2e5b122b011 100644 --- a/fs/xfs/xfs_inode.c +++ b/fs/xfs/xfs_inode.c @@ -1623,10 +1623,12 @@ xfs_itruncate_extents( goto out; /* - * Clear the reflink flag if we truncated everything. + * Clear the reflink flag if there are no data fork blocks and + * there are no extents staged in the cow fork. */ - if (ip->i_d.di_nblocks == 0 && xfs_is_reflink_inode(ip)) { - ip->i_d.di_flags2 &= ~XFS_DIFLAG2_REFLINK; + if (xfs_is_reflink_inode(ip) && ip->i_cnextents == 0) { + if (ip->i_d.di_nblocks == 0) + ip->i_d.di_flags2 &= ~XFS_DIFLAG2_REFLINK; xfs_inode_clear_cowblocks_tag(ip); }