[dm-devel] [PATCH] dm-integrity: fix a BUG if we shrink the device

[Mikulas Patocka]

The patch f6f72f32c22c ("dm integrity: don't replay journal data past the
end of the device") skips journal replay if the target sector points
beyond the end of the device. Unfortunatelly, it doesn't set the journal
entry unused, which resulted in this BUG being triggered:
BUG_ON(!journal_entry_is_unused(je))

This patch fixes the crash.

Signed-off-by: Mikulas Patocka <mpatocka at redhat.com>
Fixes: f6f72f32c22c ("dm integrity: don't replay journal data past the end of the device")
Cc: stable at vger.kernel.org	# v5.7+

---
 drivers/md/dm-integrity.c |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

Index: linux-dm/drivers/md/dm-integrity.c
===================================================================
--- linux-dm.orig/drivers/md/dm-integrity.c	2022-02-10 18:16:42.000000000 +0100
+++ linux-dm/drivers/md/dm-integrity.c	2022-03-25 18:20:27.000000000 +0100
@@ -2473,9 +2473,11 @@ static void do_journal_write(struct dm_i
 					dm_integrity_io_error(ic, "invalid sector in journal", -EIO);
 					sec &= ~(sector_t)(ic->sectors_per_block - 1);
 				}
+				if (unlikely(sec >= ic->provided_data_sectors)) {
+					journal_entry_set_unused(je);
+					continue;
+				}
 			}
-			if (unlikely(sec >= ic->provided_data_sectors))
-				continue;
 			get_area_and_offset(ic, sec, &area, &offset);
 			restore_last_bytes(ic, access_journal_data(ic, i, j), je);
 			for (k = j + 1; k < ic->journal_section_entries; k++) {