Merge branch 'iomap-5.12-fixes' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux

Pull iomap fix from Darrick Wong:
 "A single fix to the iomap code which fixes some drama when someone
  gives us a {de,ma}liciously fragmented swap file"

* 'iomap-5.12-fixes' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux:
  iomap: Fix negative assignment to unsigned sis->pages in iomap_swapfile_activate

1 files changed, 10 insertions, 0 deletions

diff --git a/fs/iomap/swapfile.c b/fs/iomap/swapfile.c
index a648dbf6991e..a5e478de1417 100644
--- a/fs/iomap/swapfile.c
+++ b/fs/iomap/swapfile.c
@@ -170,6 +170,16 @@ int iomap_swapfile_activate(struct swap_info_struct *sis,
 			return ret;
 	}
 
+	/*
+	 * If this swapfile doesn't contain even a single page-aligned
+	 * contiguous range of blocks, reject this useless swapfile to
+	 * prevent confusion later on.
+	 */
+	if (isi.nr_pages == 0) {
+		pr_warn("swapon: Cannot find a single usable page in file.\n");
+		return -EINVAL;
+	}
+
 	*pagespan = 1 + isi.highest_ppage - isi.lowest_ppage;
 	sis->max = isi.nr_pages;
 	sis->pages = isi.nr_pages - 1;