Re: [PATCH] dd: work around buffer length restrictions with oflag=direct (O_DIRECT)

[Eric Sandeen]

Eric Sandeen wrote:
> Jim Meyering wrote:

...

>> diff --git a/doc/coreutils.texi b/doc/coreutils.texi
>> index acec76e..6fa2602 100644
>> --- a/doc/coreutils.texi
>> +++ b/doc/coreutils.texi
>> @@ -7861,6 +7861,10 @@ dd invocation
>>  @opindex direct
>>  @cindex direct I/O
>>  Use direct I/O for data, avoiding the buffer cache.
>> +Note that the kernel may impose restrictions on read or write buffer sizes.
>> +For example, with an ext4 destination file system and a linux-based kernel,
>> +using @samp{oflags=direct} will cause writes to fail with @code{EINVAL} if 
>> the
>> +output buffer size is not a multiple of 512.
> 
> I dunno how much O_DIRECT tutorial you want here but alignment matters
> too :)

Sorry, I didn't mean a tutorial for -you- ... I meant "I don't know how
much of an O_DIRECT tutorial you want to put into the coreutils
documentation."  :)

-Eric