From: NeilBrown <neilb@suse.com>
Date: Tue, 17 Oct 2017 03:24:09 +0000 (+1100)
Subject: md: forbid a RAID5 from having both a bitmap and a journal.
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=230b55fa8d64007339319539f8f8e68114d08529;p=linux.git

md: forbid a RAID5 from having both a bitmap and a journal.

Having both a bitmap and a journal is pointless.
Attempting to do so can corrupt the bitmap if the journal
replay happens before the bitmap is initialized.
Rather than try to avoid this corruption, simply
refuse to allow arrays with both a bitmap and a journal.
So:
 - if raid5_run sees both are present, fail.
 - if adding a bitmap finds a journal is present, fail
 - if adding a journal finds a bitmap is present, fail.

Cc: stable@vger.kernel.org (4.10+)
Signed-off-by: NeilBrown <neilb@suse.com>
Tested-by: Joshua Kinard <kumba@gentoo.org>
Acked-by: Joshua Kinard <kumba@gentoo.org>
Signed-off-by: Shaohua Li <shli@fb.com>
---

diff --git a/drivers/md/md-bitmap.c b/drivers/md/md-bitmap.c
index b843b53b0f65a..d1b3b60669ea6 100644
--- a/drivers/md/md-bitmap.c
+++ b/drivers/md/md-bitmap.c
@@ -1816,6 +1816,12 @@ struct bitmap *bitmap_create(struct mddev *mddev, int slot)
 
 	BUG_ON(file && mddev->bitmap_info.offset);
 
+	if (test_bit(MD_HAS_JOURNAL, &mddev->flags)) {
+		pr_notice("md/raid:%s: array with journal cannot have bitmap\n",
+			  mdname(mddev));
+		return ERR_PTR(-EBUSY);
+	}
+
 	bitmap = kzalloc(sizeof(*bitmap), GFP_KERNEL);
 	if (!bitmap)
 		return ERR_PTR(-ENOMEM);
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 97afb28c6f511..6f25e3f1a1cfc 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -6362,7 +6362,7 @@ static int add_new_disk(struct mddev *mddev, mdu_disk_info_t *info)
 					break;
 				}
 			}
-			if (has_journal) {
+			if (has_journal || mddev->bitmap) {
 				export_rdev(rdev);
 				return -EBUSY;
 			}
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index a21dbd22a2fb8..a8732955f1302 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -7159,6 +7159,13 @@ static int raid5_run(struct mddev *mddev)
 			min_offset_diff = diff;
 	}
 
+	if ((test_bit(MD_HAS_JOURNAL, &mddev->flags) || journal_dev) &&
+	    (mddev->bitmap_info.offset || mddev->bitmap_info.file)) {
+		pr_notice("md/raid:%s: array cannot have both journal and bitmap\n",
+			  mdname(mddev));
+		return -EINVAL;
+	}
+
 	if (mddev->reshape_position != MaxSector) {
 		/* Check that we can continue the reshape.
 		 * Difficulties arise if the stripe we would write to