linux-ext4 - Re: [PATCH] libext2fs: Only link an inode into a directory once

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Message-ID: <20120215192537.GI11382@thunk.org>
Date:	Wed, 15 Feb 2012 14:25:37 -0500
From:	Ted Ts'o <tytso@....edu>
To:	"Darrick J. Wong" <djwong@...ibm.com>
Cc:	linux-ext4@...r.kernel.org
Subject: Re: [PATCH] libext2fs: Only link an inode into a directory once

On Fri, Jan 06, 2012 at 08:47:43PM -0800, Darrick J. Wong wrote:
> The ext2fs_link helper function link_proc does not check the value of ls->done,
> which means that if the function finds multiple empty spaces that will fit the
> new directory entry, it will create a directory entry in each of the spaces.
> Instead of doing that, check the done value and don't do anything more if we've
> already added the directory entry.
> 
> Signed-off-by: Darrick J. Wong <djwong@...ibm.com>

This should't necessary, since when we insert the directory entry, we
return with the DIRENT_ABORT bit set:

        dirent->inode = ls->inode;
        dirent->name_len = ls->namelen;
        strncpy(dirent->name, ls->name, ls->namelen);
        if (ls->sb->s_feature_incompat & EXT2_FEATURE_INCOMPAT_FILETYPE)
                dirent->name_len |= (ls->flags & 0x7) << 8;

        ls->done++;
        return DIRENT_ABORT|DIRENT_CHANGED;

Did you actually observe this happening?

Thanks,

					- Ted
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