From acd1ac3aa22fd58803a12d26b1ab7f70232f8d8d Mon Sep 17 00:00:00 2001 From: "Darrick J. Wong" Date: Thu, 1 Oct 2020 10:56:07 -0700 Subject: xfs: limit entries returned when counting fsmap records If userspace asked fsmap to count the number of entries, we cannot return more than UINT_MAX entries because fmh_entries is u32. Therefore, stop counting if we hit this limit or else we will waste time to return truncated results. Fixes: e89c041338ed ("xfs: implement the GETFSMAP ioctl") Signed-off-by: Darrick J. Wong Reviewed-by: Christoph Hellwig Reviewed-by: Chandan Babu R --- fs/xfs/xfs_fsmap.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/fs/xfs/xfs_fsmap.c b/fs/xfs/xfs_fsmap.c index 4eebcec4aae6..aa36e7daf82c 100644 --- a/fs/xfs/xfs_fsmap.c +++ b/fs/xfs/xfs_fsmap.c @@ -256,6 +256,9 @@ xfs_getfsmap_helper( /* Are we just counting mappings? */ if (info->head->fmh_count == 0) { + if (info->head->fmh_entries == UINT_MAX) + return -ECANCELED; + if (rec_daddr > info->next_daddr) info->head->fmh_entries++; -- cgit v1.2.3