Commit 85430c22 authored by Hao Li's avatar Hao Li Committed by Jonathan Corbet
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Documentation/dax: Update description of DAX policy changing 



After commit 77573fa3 ("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: default avatarHao Li <lihao2018.fnst@cn.fujitsu.com>
Reviewed-by: default avatarIra Weiny <ira.weiny@intel.com>
Link: https://lore.kernel.org/r/20210106015000.5263-1-lihao2018.fnst@cn.fujitsu.com


Signed-off-by: default avatarJonathan Corbet <corbet@lwn.net>
parent c4c6b86a

Documentation/filesystems/dax.txt

+3 −14
Original line number Diff line number Diff line
@@ -83,20 +83,9 @@ Summary 
       directories.  This has runtime constraints and limitations that are

       described in 6) below.



 6. When changing the S_DAX policy via toggling the persistent FS_XFLAG_DAX flag,

    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

 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

    files are closed by all processes.





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