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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Chao Yu <yuchao0@huawei.com>,
        Jan Kara <jack@suse.cz>
Subject: [PATCH 4.19 203/211] quota: fix wrong condition in is_quota_modification()
Date:   Thu,  3 Oct 2019 17:54:29 +0200
Message-Id: <20191003154530.006484306@linuxfoundation.org>
In-Reply-To: <20191003154447.010950442@linuxfoundation.org>
References: <20191003154447.010950442@linuxfoundation.org>
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From: Chao Yu <yuchao0@huawei.com>

commit 6565c182094f69e4ffdece337d395eb7ec760efc upstream.

Quoted from
commit 3da40c7b0898 ("ext4: only call ext4_truncate when size <= isize")

" At LSF we decided that if we truncate up from isize we shouldn't trim
  fallocated blocks that were fallocated with KEEP_SIZE and are past the
 new i_size.  This patch fixes ext4 to do this. "

And generic/092 of fstest have covered this case for long time, however
is_quota_modification() didn't adjust based on that rule, so that in
below condition, we will lose to quota block change:
- fallocate blocks beyond EOF
- remount
- truncate(file_path, file_size)

Fix it.

Link: https://lore.kernel.org/r/20190911093650.35329-1-yuchao0@huawei.com
Fixes: 3da40c7b0898 ("ext4: only call ext4_truncate when size <= isize")
CC: stable@vger.kernel.org
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 include/linux/quotaops.h |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/include/linux/quotaops.h
+++ b/include/linux/quotaops.h
@@ -22,7 +22,7 @@ static inline struct quota_info *sb_dqop
 /* i_mutex must being held */
 static inline bool is_quota_modification(struct inode *inode, struct iattr *ia)
 {
-	return (ia->ia_valid & ATTR_SIZE && ia->ia_size != inode->i_size) ||
+	return (ia->ia_valid & ATTR_SIZE) ||
 		(ia->ia_valid & ATTR_UID && !uid_eq(ia->ia_uid, inode->i_uid)) ||
 		(ia->ia_valid & ATTR_GID && !gid_eq(ia->ia_gid, inode->i_gid));
 }