[PATCH v2] Documentation/dax: Update description of DAX policy changing

From: Hao Li
Date: Tue Jan 05 2021 - 20:52:12 EST


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>
---
Changes in v2:
* simplify sentences and fix style problems.

Documentation/filesystems/dax.txt | 17 +++--------------
1 file changed, 3 insertions(+), 14 deletions(-)

diff --git a/Documentation/filesystems/dax.txt b/Documentation/filesystems/dax.txt
index 8fdb78f3c6c9..e03c20564f3a 100644
--- a/Documentation/filesystems/dax.txt
+++ b/Documentation/filesystems/dax.txt
@@ -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.


Details
--
2.29.2