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From:   Daeho Jeong <daeho43@gmail.com>
To:     linux-kernel@vger.kernel.org,
        linux-f2fs-devel@lists.sourceforge.net, kernel-team@android.com
Cc:     Daeho Jeong <daehojeong@google.com>
Subject: [PATCH] f2fs: prevent setting ioprio of thread not in merge mode
Date:   Mon,  1 Feb 2021 09:57:49 +0900
Message-Id: <20210201005749.2980575-1-daeho43@gmail.com>
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From: Daeho Jeong <daehojeong@google.com>

It causes a crash to change the ioprio of checkpoint thread not in
checkpoint=merge. I fixed that to prevent setting the ioprio of the
thread when checkpoint=merge is not enabled.

Signed-off-by: Daeho Jeong <daehojeong@google.com>
---
 fs/f2fs/sysfs.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/fs/f2fs/sysfs.c b/fs/f2fs/sysfs.c
index 100608bcd517..e38a7f6921dd 100644
--- a/fs/f2fs/sysfs.c
+++ b/fs/f2fs/sysfs.c
@@ -357,8 +357,12 @@ static ssize_t __sbi_store(struct f2fs_attr *a,
 			return -EINVAL;
 
 		cprc->ckpt_thread_ioprio = IOPRIO_PRIO_VALUE(class, data);
-		ret = set_task_ioprio(cprc->f2fs_issue_ckpt,
-				cprc->ckpt_thread_ioprio);
+		if (test_opt(sbi, MERGE_CHECKPOINT)) {
+			ret = set_task_ioprio(cprc->f2fs_issue_ckpt,
+					cprc->ckpt_thread_ioprio);
+			if (ret)
+				return ret;
+		}
 
 		return count;
 	}
-- 
2.30.0.365.g02bc693789-goog