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Date: Sun, 30 Oct 2011 09:23:47 +0800 From: Eryu Guan <guaneryu@...il.com> To: "Ted Ts'o" <tytso@....edu> Cc: linux-ext4@...r.kernel.org Subject: Re: [PATCH] ext4: Avoid creating new file in append-only dir when open(2) return error On Sun, Oct 30, 2011 at 2:54 AM, Ted Ts'o <tytso@....edu> wrote: > On Sat, Oct 29, 2011 at 02:02:41AM +0800, Eryu Guan wrote: >> Newly created file on ext4 inherits inode flags from parent directory, >> so new inode created in append-only directory has S_APPEND flag set, >> may_open() called by do_last() checks that flag then returns -EPERM, >> but at that time the new inode is already created. > > I have the following patch in the ext4 tree that should take care of > this issue for ext2/3/4. > > - Ted > > ext2,ext3,ext4: don't inherit APPEND_FL or IMMUTABLE_FL for new inodes > > This doesn't make much sense, and it exposes a bug in the kernel where > attempts to create a new file in an append-only directory using > O_CREAT will fail (but still leave a zero-length file). This was > discovered when xfstests #79 was generalized so it could run on all > file systems. > I also found this by checking xfstests 079 and wanted to fix it in a way not changing the current behavior. Masking out EXTN_APPEND_FL from inherit bits makes more sense. I think I should resend the comment cleanup part. Thanks! Eryu Guan -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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