From: Sahitya Tummala <stummala@codeaurora.org>
Date: Fri, 18 May 2018 06:21:52 +0000 (+0530)
Subject: f2fs: Fix deadlock in shutdown ioctl
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=c92d09e35d2ddf8ec3e3e3c755241cfde670236c;p=GitHub%2Fmoto-9609%2Fandroid_kernel_motorola_exynos9610.git

f2fs: Fix deadlock in shutdown ioctl

[ Upstream commit 60b2b4ee2bc01dd052f99fa9d65da2232102ef8e ]

f2fs_ioc_shutdown() ioctl gets stuck in the below path
when issued with F2FS_GOING_DOWN_FULLSYNC option.

__switch_to+0x90/0xc4
percpu_down_write+0x8c/0xc0
freeze_super+0xec/0x1e4
freeze_bdev+0xc4/0xcc
f2fs_ioctl+0xc0c/0x1ce0
f2fs_compat_ioctl+0x98/0x1f0

Signed-off-by: Sahitya Tummala <stummala@codeaurora.org>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index 72c6a9e9a9b4..97537ce5127c 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -1808,9 +1808,11 @@ static int f2fs_ioc_shutdown(struct file *filp, unsigned long arg)
 	if (get_user(in, (__u32 __user *)arg))
 		return -EFAULT;
 
-	ret = mnt_want_write_file(filp);
-	if (ret)
-		return ret;
+	if (in != F2FS_GOING_DOWN_FULLSYNC) {
+		ret = mnt_want_write_file(filp);
+		if (ret)
+			return ret;
+	}
 
 	switch (in) {
 	case F2FS_GOING_DOWN_FULLSYNC:
@@ -1838,7 +1840,8 @@ static int f2fs_ioc_shutdown(struct file *filp, unsigned long arg)
 	}
 	f2fs_update_time(sbi, REQ_TIME);
 out:
-	mnt_drop_write_file(filp);
+	if (in != F2FS_GOING_DOWN_FULLSYNC)
+		mnt_drop_write_file(filp);
 	return ret;
 }