From: Shaohua Li <shli@fb.com>
Date: Wed, 29 Aug 2018 11:05:42 -0700
Subject: [PATCH] md/raid5-cache: disable reshape completely
Git-commit: e254de6bcf3f5b6e78a92ac95fb91acef8adfe1a
Patch-mainline: v4.19-rc3
References: git-fixes

We don't support reshape yet if an array supports log device. Previously we
determine the fact by checking ->log. However, ->log could be NULL after a log
device is removed, but the array is still marked to support log device. Don't
allow reshape in this case too. User can disable log device support by setting
'consistency_policy' to 'resync' then do reshape.

Reported-by: Xiao Ni <xni@redhat.com>
Tested-by: Xiao Ni <xni@redhat.com>
Signed-off-by: Shaohua Li <shli@fb.com>
Acked-by: NeilBrown <neilb@suse.com>

---
 drivers/md/raid5-log.h |    5 +++++
 drivers/md/raid5.c     |    6 +++---
 2 files changed, 8 insertions(+), 3 deletions(-)

--- a/drivers/md/raid5-log.h
+++ b/drivers/md/raid5-log.h
@@ -44,6 +44,11 @@ extern int ppl_modify_log(struct r5conf
 extern void ppl_quiesce(struct r5conf *conf, int quiesce);
 extern int ppl_handle_flush_request(struct r5l_log *log, struct bio *bio);
 
+static inline bool raid5_has_log(struct r5conf *conf)
+{
+	return test_bit(MD_HAS_JOURNAL, &conf->mddev->flags);
+}
+
 static inline bool raid5_has_ppl(struct r5conf *conf)
 {
 	return test_bit(MD_HAS_PPL, &conf->mddev->flags);
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -736,7 +736,7 @@ static bool stripe_can_batch(struct stri
 {
 	struct r5conf *conf = sh->raid_conf;
 
-	if (conf->log || raid5_has_ppl(conf))
+	if (raid5_has_log(conf) || raid5_has_ppl(conf))
 		return false;
 	return test_bit(STRIPE_BATCH_READY, &sh->state) &&
 		!test_bit(STRIPE_BITMAP_PENDING, &sh->state) &&
@@ -7731,7 +7731,7 @@ static int raid5_resize(struct mddev *md
 	sector_t newsize;
 	struct r5conf *conf = mddev->private;
 
-	if (conf->log || raid5_has_ppl(conf))
+	if (raid5_has_log(conf) || raid5_has_ppl(conf))
 		return -EINVAL;
 	sectors &= ~((sector_t)conf->chunk_sectors - 1);
 	newsize = raid5_size(mddev, sectors, mddev->raid_disks);
@@ -7782,7 +7782,7 @@ static int check_reshape(struct mddev *m
 {
 	struct r5conf *conf = mddev->private;
 
-	if (conf->log || raid5_has_ppl(conf))
+	if (raid5_has_log(conf) || raid5_has_ppl(conf))
 		return -EINVAL;
 	if (mddev->delta_disks == 0 &&
 	    mddev->new_layout == mddev->layout &&