linux-kernel - Re: [PATCH 1/5] WIP: Add syscall unlinkat

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Message-ID: <54D071AA.1030302@ahsoftware.de>
Date:	Tue, 03 Feb 2015 07:58:50 +0100
From:	Alexander Holler <holler@...oftware.de>
To:	Al Viro <viro@...IV.linux.org.uk>
CC:	linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/5] WIP: Add syscall unlinkat_s (currently x86* only)

Am 03.02.2015 um 07:05 schrieb Al Viro:
> On Mon, Feb 02, 2015 at 06:05:09PM +0100, Alexander Holler wrote:
>> +	if (inode) {
>> +		// TODO:
>> +		// if (inode is file and 's' flag is set)
>> +		// 	secure = true;
>> +		if (!secure)
>> +			iput(inode);	/* truncate the inode here */
>> +		else {
>> +			struct super_block *sb = inode->i_sb;
>> +			if (sb->s_op->set_secure_delete)
>> +				sb->s_op->set_secure_delete(sb, true);
>> +			// TODO: We should fail if secure isn't supported,
>> +			// look up how that's possible here.
>> +			iput(inode);	/* truncate the inode here */
>> +			// TODO: check if sb is still valid after the inode is gone
>> +			sync_filesystem(sb);
>> +			if (sb->s_op->set_secure_delete)
>> +				sb->s_op->set_secure_delete(sb, false);
>> +		}
> 
> Charming.  Now, what exactly happens if two such syscalls overlap in time?

What do you think will happen? I assume you haven't looked at how I've
implemented set_secure_delete(). CHarming.

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