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Date:   Mon, 10 Jun 2019 00:38:28 -0400
From:   "Theodore Ts'o" <tytso@mit.edu>
To:     Eric Biggers <ebiggers@kernel.org>
Cc:     Wang Shilong <wshilong@ddn.com>,
        Wang Shilong <wangshilong1991@gmail.com>,
        "linux-ext4@vger.kernel.org" <linux-ext4@vger.kernel.org>,
        "linux-f2fs-devel@lists.sourceforge.net" 
        <linux-f2fs-devel@lists.sourceforge.net>,
        Andreas Dilger <adilger@dilger.ca>
Subject: Re: =?utf-8?B?5Zue5aSNOiBbZjJmcy1kZXZdIFtQ?= =?utf-8?Q?ATCH?= 1/2]
 ext4: only set project inherit bit for directory
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On Fri, Jun 07, 2019 at 11:14:52AM -0700, Eric Biggers wrote:
> 
> Existing versions of chattr can't be changed, and people don't necessarily
> upgrade the kernel and e2fsprogs at the same time.  So (1) wouldn't really work.
> 
> A better solution might be to make FS_IOC_GETFLAGS and FS_IOC_FSGETXATTR never
> return the project inherit flag on regular files.

I've amended this patch by adding the following to fix it for
FS_IOC_GETFLAGS (which is chattr uses):

diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c
index 7af835ac8d23..74648d42c69b 100644
--- a/fs/ext4/ioctl.c
+++ b/fs/ext4/ioctl.c
@@ -779,6 +779,8 @@ long ext4_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 		return ext4_ioc_getfsmap(sb, (void __user *)arg);
 	case EXT4_IOC_GETFLAGS:
 		flags = ei->i_flags & EXT4_FL_USER_VISIBLE;
+		if (S_ISREG(inode->i_mode))
+			flags &= ~EXT4_PROJINHERIT_FL;
 		return put_user(flags, (int __user *) arg);
 	case EXT4_IOC_SETFLAGS: {
 		int err;

						- Ted