From 8fc18580ec17f90beac4c933fbe4c74dcd3b7f36 Mon Sep 17 00:00:00 2001 From: "Darrick J. Wong" Date: Thu, 10 Sep 2026 22:53:55 -0700 Subject: [PATCH] xfs: don't call xfs_exchange_range_finish for a dry run LOLLM noticed that we strip file privileges and whatnot even for a dry run. We also shouldn't flush dirty data to disk or trim COW staging events for a dry run. Neither of those behaviors are allowed by the manpage, so fix that by exiting early on DRY_RUN in various functions. Cc: stable@vger.kernel.org # v6.10 Fixes: 42672471f938cd ("xfs: bind together the front and back ends of the file range exchange code") Signed-off-by: Darrick J. Wong Assisted-by: LOLLM # finding obvious bugs Reviewed-by: Christoph Hellwig Signed-off-by: Carlos Maiolino --- fs/xfs/xfs_exchrange.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) diff --git a/fs/xfs/xfs_exchrange.c b/fs/xfs/xfs_exchrange.c index 07090487c581..fafb4e3f065c 100644 --- a/fs/xfs/xfs_exchrange.c +++ b/fs/xfs/xfs_exchrange.c @@ -633,6 +633,9 @@ xfs_exchrange_prep( if (error) return error; + if (fxr->flags & XFS_EXCHANGE_RANGE_DRY_RUN) + return 0; + trace_xfs_exchrange_flush(fxr, ip1, ip2); /* Flush the relevant ranges of both files. */ @@ -709,9 +712,11 @@ xfs_exchrange_contents( * other file write would do. This may involve turning on support for * logged xattrs if either file has security capabilities. */ - error = xfs_exchange_range_finish(fxr); - if (error) - goto out_unlock; + if (!(fxr->flags & XFS_EXCHANGE_RANGE_DRY_RUN)) { + error = xfs_exchange_range_finish(fxr); + if (error) + goto out_unlock; + } out_unlock: xfs_iunlock2_io_mmap(ip1, ip2);