On 2021/1/5 0:36, Ira Weiny wrote:
> On Mon, Jan 04, 2021 at 10:40:40AM +0800, Hao Li wrote:
>> After commit 77573fa310d9 ("fs: Kill DCACHE_DONTCACHE dentry even if
>> DCACHE_REFERENCED is set"), changes to DAX policy will take effect
>> as soon as all references to this file are gone.
>>
>> Update the documentation accordingly.
>>
>> Signed-off-by: Hao Li <lihao2018.fnst@xxxxxxxxxxxxxx>
>> ---
>> Documentation/filesystems/dax.txt | 15 ++-------------
>> 1 file changed, 2 insertions(+), 13 deletions(-)
>>
>> diff --git a/Documentation/filesystems/dax.txt b/Documentation/filesystems/dax.txt
>> index 8fdb78f3c6c9..a5af22831087 100644
>> --- a/Documentation/filesystems/dax.txt
>> +++ b/Documentation/filesystems/dax.txt
>> @@ -84,19 +84,8 @@ Summary
>> described in 6) below.
>>
>> 6. When changing the S_DAX policy via toggling the persistent FS_XFLAG_DAX flag,
> ^^
> I would delete this '.' as well.
>
>> - the change in behaviour for existing regular files may not occur
>> - immediately. If the change must take effect immediately, the administrator
>> - needs to:
>> -
>> - a) stop the application so there are no active references to the data set
>> - the policy change will affect
>> -
>> - b) evict the data set from kernel caches so it will be re-instantiated when
>> - the application is restarted. This can be achieved by:
>> -
>> - i. drop-caches
>> - ii. a filesystem unmount and mount cycle
>> - iii. a system reboot
>> + the change to existing regular file won't take effect until the file is closed
> ^^^^^
> files
>
>> + by all processes or all processes referencing the file are stopped.
>
> So how about:
>
> 6. When changing the S_DAX policy via toggling the persistent FS_XFLAG_DAX
> flag the change to existing regular files won't take effect until the file
> is closed by all processes or all processes referencing the file are
> stopped.
>
> I also feel like mentioning the stoppage of process' is redundant as users
> should know that will result in the closing of those FDs but I'm ok leaving it
> if others like it.
Thanks, it's much better than before.
Regards,
Hao Li
>
>
> Ira
>
>>
>>
>> Details
>> --
>> 2.29.2
>>
>>
>>
>
>
