This is a note to let you know that I've just added the patch titled xfs: limit entries returned when counting fsmap records to the 5.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: xfs-limit-entries-returned-when-counting-fsmap-recor.patch and it can be found in the queue-5.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit c53150ed001828504edf58257d019aed5bfedaed Author: Darrick J. Wong <darrick.wong@xxxxxxxxxx> Date: Thu Oct 1 10:56:07 2020 -0700 xfs: limit entries returned when counting fsmap records [ Upstream commit acd1ac3aa22fd58803a12d26b1ab7f70232f8d8d ] 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 <darrick.wong@xxxxxxxxxx> Reviewed-by: Christoph Hellwig <hch@xxxxxx> Reviewed-by: Chandan Babu R <chandanrlinux@xxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/fs/xfs/xfs_fsmap.c b/fs/xfs/xfs_fsmap.c index c13754e119be1..5b864985bc648 100644 --- a/fs/xfs/xfs_fsmap.c +++ b/fs/xfs/xfs_fsmap.c @@ -255,6 +255,9 @@ 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++;