[SCM] Samba Shared Repository - branch master updated
Jeremy Allison
jra at samba.org
Sat Mar 25 03:42:02 UTC 2017
The branch, master has been updated
via 1b36cda WHATSNEW: Document "strict sync" default change.
via ed483d8 s3: smbd: Change "strict sync" paramter from "no" to "yes" for 4.7.0.
from a74fef0 Revert "selftest: temporary skip samba.blackbox.pdbtest.s4winbind"
https://git.samba.org/?p=samba.git;a=shortlog;h=master
- Log -----------------------------------------------------------------
commit 1b36cda7cf20746f85b18a52e2e24fbc5ba73535
Author: Jeremy Allison <jra at samba.org>
Date: Thu Mar 23 09:06:27 2017 -0700
WHATSNEW: Document "strict sync" default change.
Signed-off-by: Jeremy Allison <jra at samba.org>
Reviewed-by: Christof Schmitt <cs at samba.org>
Autobuild-User(master): Jeremy Allison <jra at samba.org>
Autobuild-Date(master): Sat Mar 25 04:41:19 CET 2017 on sn-devel-144
commit ed483d8e570700a303e11bc03d6250cd0ae4aaed
Author: Jeremy Allison <jra at samba.org>
Date: Wed Mar 22 19:22:31 2017 -0700
s3: smbd: Change "strict sync" paramter from "no" to "yes" for 4.7.0.
Document change and modify in loadparm.c.
Safer default for new installs and vendors.
Signed-off-by: Jeremy Allison <jra at samba.org>
Reviewed-by: Christof Schmitt <cs at samba.org>
-----------------------------------------------------------------------
Summary of changes:
WHATSNEW.txt | 6 ++++
docs-xml/smbdotconf/tuning/strictsync.xml | 48 +++++++++++++++++++------------
lib/param/loadparm.c | 2 ++
source3/param/loadparm.c | 2 +-
4 files changed, 39 insertions(+), 19 deletions(-)
Changeset truncated at 500 lines:
diff --git a/WHATSNEW.txt b/WHATSNEW.txt
index dd60cd2..cda61ef 100644
--- a/WHATSNEW.txt
+++ b/WHATSNEW.txt
@@ -16,12 +16,18 @@ UPGRADING
NEW FEATURES/CHANGES
====================
+The "strict sync" global parameter has been changed from
+a default of "no" to "yes". This means smbd will by default
+obey client requests to synchronize unwritten data in operating
+system buffers safely onto disk. This is a safer default setting
+for modern SMB1/2/3 clients.
smb.conf changes
================
Parameter Name Description Default
-------------- ----------- -------
+ strict sync Default changed yes
KNOWN ISSUES
diff --git a/docs-xml/smbdotconf/tuning/strictsync.xml b/docs-xml/smbdotconf/tuning/strictsync.xml
index 5cfd388..f2e3788 100644
--- a/docs-xml/smbdotconf/tuning/strictsync.xml
+++ b/docs-xml/smbdotconf/tuning/strictsync.xml
@@ -3,26 +3,38 @@
type="boolean"
xmlns:samba="http://www.samba.org/samba/DTD/samba-doc">
<description>
- <para>Many Windows applications (including the Windows 98 explorer
- shell) seem to confuse flushing buffer contents to disk with doing
- a sync to disk. Under UNIX, a sync call forces the thread to be
- suspended until the kernel has ensured that all outstanding data in
- kernel disk buffers has been safely stored onto stable storage.
- This is very slow and should only be done rarely. Setting this
- parameter to <constant>no</constant> (the default) means that
- <citerefentry><refentrytitle>smbd</refentrytitle>
- <manvolnum>8</manvolnum></citerefentry> ignores the Windows
- applications requests for a sync call. There is only a possibility
- of losing data if the operating system itself that Samba is running
- on crashes, so there is little danger in this default setting. In
- addition, this fixes many performance problems that people have
- reported with the new Windows98 explorer shell file copies.</para>
+ <para>This parameter controls whether Samba honors a request
+ from an SMB client to ensure any outstanding operating system
+ buffer contents held in memory are safely written onto stable
+ storage on disk. If set to <constant>yes</constant>, which is
+ the default, then Windows applications can force the smbd server
+ to synchronize unwritten data onto the disk. If set to
+ <constant>no</constant> then smbd will ignore client
+ requests to synchronize unwritten data onto stable storage on
+ disk.</para>
+
+ <para>In Samba 4.7.0, the default for this parameter changed from
+ <constant>no</constant> to <constant>yes</constant> to better
+ match the expectations of SMB2/3 clients and improve application
+ safety when running against smbd.</para>
+
<para>The flush request from SMB2/3 clients is handled
- asynchronously, so for these clients setting the parameter
- to <constant>yes</constant> does not block the processing of other
- requests in the smbd process.</para>
+ asynchronously inside smbd, so leaving the parameter as the default
+ value of <constant>yes</constant> does not block the processing of
+ other requests to the smbd process.</para>
+
+ <para>Legacy Windows applications (such as the Windows 98 explorer
+ shell) seemed to confuse writing buffer contents to the operating
+ system with synchronously writing outstanding data onto stable storage
+ on disk. Changing this parameter to <constant>no</constant> means that
+ <citerefentry><refentrytitle>smbd</refentrytitle>
+ <manvolnum>8</manvolnum></citerefentry> will ignore the Windows
+ applications request to synchronize unwritten data onto disk. Only
+ consider changing this if smbd is serving obsolete SMB1 Windows clients
+ prior to Windows XP (Windows 98 and below). There should be no need to
+ change this setting for normal operations.</para>
</description>
<related>sync always</related>
-<value type="default">no</value>
+<value type="default">yes</value>
</samba:parameter>
diff --git a/lib/param/loadparm.c b/lib/param/loadparm.c
index 335c54a..cedf8fa 100644
--- a/lib/param/loadparm.c
+++ b/lib/param/loadparm.c
@@ -2832,6 +2832,8 @@ struct loadparm_context *loadparm_init(TALLOC_CTX *mem_ctx)
lpcfg_do_global_parameter(lp_ctx, "strict locking", "Auto");
+ lpcfg_do_global_parameter(lp_ctx, "strict sync", "yes");
+
lpcfg_do_global_parameter(lp_ctx, "map readonly", "yes");
lpcfg_do_global_parameter(lp_ctx, "allow trusted domains", "yes");
diff --git a/source3/param/loadparm.c b/source3/param/loadparm.c
index c65e613..57220a6 100644
--- a/source3/param/loadparm.c
+++ b/source3/param/loadparm.c
@@ -207,7 +207,7 @@ static struct loadparm_service sDefault =
.sync_always = false,
.strict_allocate = false,
.strict_rename = false,
- .strict_sync = false,
+ .strict_sync = true,
.mangling_char = '~',
.copymap = NULL,
.delete_readonly = false,
--
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