linux-kernel - Re: [patch] document ext3 a bit better

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Message-ID: <4967DF86.6040709@oracle.com>
Date:	Fri, 09 Jan 2009 15:36:38 -0800
From:	Randy Dunlap <randy.dunlap@...cle.com>
To:	Jiri Kosina <jkosina@...e.cz>
CC:	Pavel Machek <pavel@...e.cz>, Jonathan Corbet <corbet@....net>,
	Theodore Tso <tytso@....edu>,
	kernel list <linux-kernel@...r.kernel.org>,
	Andrew Morton <akpm@...l.org>, mtk.manpages@...il.com,
	linux-doc@...r.kernel.org,
	Trivial patch monkey <trivial@...nel.org>
Subject: Re: [patch] document ext3 a bit better

Jiri Kosina wrote:
> On Tue, 6 Jan 2009, Pavel Machek wrote:
> 
>> On Mon 2009-01-05 09:57:13, Theodore Tso wrote:
>>> On Sun, Jan 04, 2009 at 11:34:33PM +0100, Pavel Machek wrote:
>>>> @@ -14,6 +14,11 @@ Options
>>>>  When mounting an ext3 filesystem, the following option are accepted:
>>>>  (*) == default
>>>>  
>>>> +ro			Mount filesystem read only. Note that ext3 will replay
>>>> +			the journal (and thus write to the partition) even when
>>>> +			mounted "read only". "ro, noload" can be used to prevent
>>>> +			writes to the filesystem.
>>> I'd sugest "ro,noload" since the spaces screw up the mount options
>>> parsing both on the command-line and in /etc/fstab.  So how about:
>>>
>>> 	Using the mount options "ro,noload" can be used....
>> Too many "using", but yes, fixed, thanks.
>>
>>>> @@ -95,6 +102,8 @@ debug			Extra debugging information is s
>>>>  errors=remount-ro(*)	Remount the filesystem read-only on an error.
>>>>  errors=continue		Keep going on a filesystem error.
>>>>  errors=panic		Panic and halt the machine if an error occurs.
>>>> +			(Note that default is overriden by superblock
>>>> +			setting on most systems).
>>> The default is always specified by the superblock setting.  So users
>>> will probably find it easier to understand if we remove the "(*)" and
>>> to add the explanatory comment:
>>>
>>> 			(These mount options override the errors behavior
>>> 			specified in the superblock, which can be configured
>>> 			using tune2fs)
>>>
>>> Pavel, thanks for working on improving the documentation; with these
>>> fixes,
>> Thanks!
>>
>> ---
>>
>> ext3 has quite unexpected semantics or "ro" and defaults are
>> not what they are documented to be, due to mkfs override.
>>
>> Signed-off-by: Pavel Machek <pavel@...e.cz>
>> Signed-off-by: "Theodore Ts'o" <tytso@....edu>
>>
>> diff --git a/Documentation/filesystems/ext3.txt b/Documentation/filesystems/ext3.txt
>> index 9dd2a3b..49c08bf 100644
>> --- a/Documentation/filesystems/ext3.txt
>> +++ b/Documentation/filesystems/ext3.txt
>> @@ -14,6 +14,11 @@ Options
>>  When mounting an ext3 filesystem, the following option are accepted:
>>  (*) == default
>>  
>> +ro			Mount filesystem read only. Note that ext3 will replay
>> +			the journal (and thus write to the partition) even when
>> +			mounted "read only". Mount options "ro,noload" can be
>> +			used to prevent writes to the filesystem.
>> +
>>  journal=update		Update the ext3 file system's journal to the current
>>  			format.
>>  
>> @@ -27,7 +32,9 @@ journal_dev=devnum	When the external jou
>>  			identified through its new major/minor numbers encoded
>>  			in devnum.
>>  
>> -noload			Don't load the journal on mounting.
>> +noload			Don't load the journal on mounting. Note that this forces
>> +			mount of inconsistent filesystem, which can lead to
>> +			various problems.
>>  
>>  data=journal		All data are committed into the journal prior to being
>>  			written into the main file system.
>> @@ -92,9 +99,12 @@ nocheck
>>  
>>  debug			Extra debugging information is sent to syslog.
>>  
>> -errors=remount-ro(*)	Remount the filesystem read-only on an error.
>> +errors=remount-ro	Remount the filesystem read-only on an error.
>>  errors=continue		Keep going on a filesystem error.
>>  errors=panic		Panic and halt the machine if an error occurs.
>> +			(These mount options override the errors behavior
>> +			specified in the superblock, which can be 
>> +			configured using tune2fs.)			
>>  
>>  data_err=ignore(*)	Just print an error message if an error occurs
>>  			in a file data buffer in ordered mode.
>>
> 
> So, documentation guys, are you going to take this patch through the 
> Documentation tree (tytso already Signed off on that), or should I take it 

                     (probably should be Acked-by or Reviewed-by
                      if he isn't merging it)

> through trivial tree?

I'm so far behind on doc patches that I haven't read any of this thread
yet, so you can merge it IMO.

Thanks,
-- 
~Randy
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