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From:   yu kuai <yukuai3@huawei.com>
To:     <hughd@google.com>, <akpm@linux-foundation.org>
CC:     <linux-mm@kvack.org>, <linux-kernel@vger.kernel.org>,
        <linux-fsdevel@vger.kernel.org>, <yukuai3@huawei.com>,
        <yi.zhang@huawei.com>, <zhengbin13@huawei.com>
Subject: [PATCH] mm/shmem.c: don't set 'seals' to 'F_SEAL_SEAL' in shmem_get_inode
Date:   Wed, 27 Nov 2019 12:00:51 +0800
Message-ID: <20191127040051.39169-1-yukuai3@huawei.com>
MIME-Version: 1.0
Content-Type: text/plain
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

'seals' is set to 'F_SEAL_SEAL' in shmem_get_inode, which means "prevent
further seals from being set", thus sealing API will be useless and many
code in shmem.c will never be reached. For example:

shmem_setattr
	if ((newsize < oldsize && (info->seals & F_SEAL_SHRINK)) ||
	    (newsize > oldsize && (info->seals & F_SEAL_GROW)))
		return -EPERM;

So, initialize 'seals' to zero is more reasonable.

Signed-off-by: yu kuai <yukuai3@huawei.com>
---
 mm/shmem.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/mm/shmem.c b/mm/shmem.c
index 165fa6332993..7b032b347bda 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -2256,7 +2256,6 @@ static struct inode *shmem_get_inode(struct super_block *sb, const struct inode
 		memset(info, 0, (char *)inode - (char *)info);
 		spin_lock_init(&info->lock);
 		atomic_set(&info->stop_eviction, 0);
-		info->seals = F_SEAL_SEAL;
 		info->flags = flags & VM_NORESERVE;
 		INIT_LIST_HEAD(&info->shrinklist);
 		INIT_LIST_HEAD(&info->swaplist);
-- 
2.17.2