Re: [BUG] copy file result with zero
From: Dave Young
Date: Sat Oct 01 2011 - 19:37:49 EST
On Sat, Oct 1, 2011 at 10:39 PM, Ted Ts'o <tytso@xxxxxxx> wrote:
> On Sat, Oct 01, 2011 at 10:01:35PM +0800, Dave Young wrote:
>> Weird problem, when I build app from source,
>> make; make install
>> run the command, but got "cannot execute binary file"
>> hexdump shows the installed binary is full of zero
>> Is it related to ext4 fiemap problem described below?
> There is general agreement that /bin/cp should not have been relying
> on FIEMAP, and I believe the more recent versions of /bin/cp have
> removed that code by default pending implementation of
> SEEK_HOLE/SEEK_DATA. ÂThat being said, ext4 had a workaround to its
> FIEMAP implementation that landed in 2.6.39, and you're using
Do you means It should work in 3.1.0-rc6 even with cp which depends fiemap?
>> I finally managed to find the way to reproduce this:
>> just cp a elf binary A Âto file B, then cp B to file C, Âthen you will get:
>> A == B != C
>> cp /bin/ls ls1
>> cp ls1 ls2
>> ls2 will be filled with zero
> If you add a "sync" between the two copies, does that work around the
> problem? ÂI bet it will...
Yes, it works
> My suggestion is to upgrade to a newer version of coreutils that
> doesn't try to use FIEMAP.
Thanks, will try
> Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â- Ted
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