lkml.org 
[lkml]   [2007]   [Jan]   [16]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] return ENOENT from ext3_link when racing with unlink
Eric Sandeen wrote:
> An update from the earlier thread, [PATCH] [RFC] remove ext3 inode
> from orphan list when link and unlink race
>
> I think this is better than the original idea of trying to handle the
> race;
> I've seen that the orphan inode list can get corrupted, but there may
> well
> be other implications of the race which haven't yet been exposed. I
> think
> it's safer to simply return -ENOENT in this race window, and avoid other
> potential problems. Anything wrong with this?
>
> Thanks for the comments suggesting this approach in the prior thread.
>
> Thanks,
>
> -Eric
>
> ---
>
> Return -ENOENT from ext[34]_link if we've raced with unlink and
> i_nlink is 0. Doing otherwise has the potential to corrupt the
> orphan inode list, because we'd wind up with an inode with a
> non-zero link count on the list, and it will never get properly
> cleaned up & removed from the orphan list before it is freed.
>
> Signed-off-by: Eric Sandeen <sandeen@redhat.com>
>
> Index: linux-2.6.19/fs/ext3/namei.c
> ===================================================================
> --- linux-2.6.19.orig/fs/ext3/namei.c
> +++ linux-2.6.19/fs/ext3/namei.c
> @@ -2191,6 +2191,8 @@ static int ext3_link (struct dentry * ol
>
> if (inode->i_nlink >= EXT3_LINK_MAX)
> return -EMLINK;
> + if (inode->i_nlink == 0)
> + return -ENOENT;
>
> retry:
> handle = ext3_journal_start(dir, EXT3_DATA_TRANS_BLOCKS(dir->i_sb) +
> Index: linux-2.6.19/fs/ext4/namei.c
> ===================================================================
> --- linux-2.6.19.orig/fs/ext4/namei.c
> +++ linux-2.6.19/fs/ext4/namei.c
> @@ -2189,6 +2189,8 @@ static int ext4_link (struct dentry * ol
>
> if (inode->i_nlink >= EXT4_LINK_MAX)
> return -EMLINK;
> + if (inode->i_nlink == 0)
> + return -ENOENT;
>
> retry:
> handle = ext4_journal_start(dir, EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
>

Just out of curosity, what keeps i_nlink from going to 0 immediately
after the new test is executed?

Thanx...

ps
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2007-01-16 23:27    [W:0.039 / U:0.696 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site