https://jira.whamcloud.com This file is an XML representation of an issue en-us 9.4.14 940014 05-12-2023 https://jira.whamcloud.com/browse/LU-7543 Lustre <p>The <tt>obd_connect_flags</tt> field has almost run out of bits to add new features. Reserve the last few free bits for upcoming features and the very last bit for <tt>OBD_CONNECT_FLAGS2</tt> to create <tt>obd_connect_flags2</tt>, to have space for new features. Any feature that is using a bit in <tt>obd_connect_flags2</tt> needs to understand <tt>OBD_CONNECT_FLAGS2</tt> as well.</p> LU-7543

reserve lock flags for upcoming features and future expansion

Bug Major Resolved Fixed nasf nasf Fri, 11 Dec 2015 03:27:26 +0000 Fri, 23 Sep 2016 13:12:23 +0000 Wed, 6 Jan 2016 03:48:34 +0000 Lustre 2.8.0 0 4 <p>Fan Yong (fan.yong@intel.com) uploaded a new patch: <a href="http://review.whamcloud.com/17559" class="external-link" target="_blank" rel="nofollow noopener">http://review.whamcloud.com/17559</a><br/> Subject: <a href="https://jira.whamcloud.com/browse/LU-7543" title="reserve lock flags for upcoming features and future expansion" class="issue-link" data-issue-key="LU-7543"><del>LU-7543</del></a> obd: reserve some connection flags<br/> Project: fs/lustre-release<br/> Branch: master<br/> Current Patch Set: 1<br/> Commit: 799a54e6079c20a995ad2c89f07722305214851c</p> <p>The connection handing code on the server would need to add <tt>OBD_CONNECT_FLAGS2</tt> checking, and then add a separate <tt>OST_CONNECT2_SUPPORTED</tt> <tt>MDT_CONNECT2_SUPPORTED</tt>, and <tt>MGS_CONNECT2_SUPPORTED</tt> masks for that word. Strictly speaking, clients shouldn't care if <tt>obd_connect_flags2</tt> is masked off or not, since an older server will drop <tt>OBD_CONNECT_FLAGS2</tt> and the client should check if this is still valid before trying to check <tt>obd_connect_flags2</tt> features.</p> <p>It might be best to hide this complexity inside accessor functions like:</p> <div class="code panel" style="border-width: 1px;"><div class="codeContent panelContent"> <pre class="code-java">bool obd_connect_has_grant(struct obd_connect_data *ocd) { <span class="code-keyword">return</span> ocd-&gt;obd_connect_data &amp; OBD_CONNECT_GRANT; } bool obd_connect_has_future_feature(struct obd_connect_data *ocd) { <span class="code-keyword">return</span> ocd-&gt;obd_connect_data &amp; OBD_CONNECT_FLAGS2 &amp;&amp; ocd-&gt;obd_connect_data2 &amp; OBD_CONNECT2_FUTURE_FEATURE; } </pre> </div></div> <p>Otherwise, there is a danger of someone using an OBD_CONNECT2_* flag with obd_connect_data incorrectly, and having multiple checks throughout the code is just ugly. This would also allow us to change the above helper function to "return false" if a feature is disabled at compile time for some reason without having to mess with the rest of the code.</p> <p>There are several older feature flags that could begin to be deprecated, for "features" that were more like transient bug fixes and not expected to ever be removed, or features that are always set on all connections and provide no value:</p> <ul class="alternate" type="square"> <li><tt>OBD_CONNECT_CROW</tt>: was never used in production, though it might some day be implemented?</li> <li><tt>OBD_CONNECT_NODEVOH</tt>: change <tt>mdt_finish_open()</tt> to assume it is always set, it is a bugfix from 1.4.6</li> <li><tt>OBD_CONNECT_REQPORTAL</tt>: change <tt>osc_import_event()</tt> to assume this feature is supported, bugfix from 1.5</li> <li><tt>OBD_CONNECT_JOIN</tt>: deprecated feature since 1.8.0, 2.0.66</li> <li><tt>OBD_CONNECT_MDS/OSS_CAPA</tt>: removed in 2.8 so stop sending this flag in <tt>client_common_fill_super()</tt>, and remove checks in <tt>tgt_init_sec_level()</tt></li> <li><tt>OBD_CONNECT_RMT_CLIENT+_FORCE</tt>: never used in production and not safe anyway, remove checks from <tt>tgt_init_sec_level()</tt></li> <li><tt>OBD_CONNECT_AT</tt>: mandatory feature since 1.6, assume it is set in <tt>rev_import_flags_update()</tt>, <tt>ptlrpc_connect_set_flags()</tt>, <tt>ptl_send_rpc()</tt></li> <li><tt>OBD_CONNECT_REAL</tt>: I don't <em>think</em> this does anything useful since 2.4 removed LMV from MDS, and was only ever an internal flag</li> </ul> <p>Fan Yong (fan.yong@intel.com) uploaded a new patch: <a href="http://review.whamcloud.com/17644" class="external-link" target="_blank" rel="nofollow noopener">http://review.whamcloud.com/17644</a><br/> Subject: <a href="https://jira.whamcloud.com/browse/LU-7543" title="reserve lock flags for upcoming features and future expansion" class="issue-link" data-issue-key="LU-7543"><del>LU-7543</del></a> obd: reserve connection flag OBD_CONNECT_SUBTREE<br/> Project: fs/lustre-release<br/> Branch: master<br/> Current Patch Set: 1<br/> Commit: 6a5cd7efd43be27ed2d8edd2d5b1973d5e6da933</p> <p>Fan Yong (fan.yong@intel.com) uploaded a new patch: <a href="http://review.whamcloud.com/17645" class="external-link" target="_blank" rel="nofollow noopener">http://review.whamcloud.com/17645</a><br/> Subject: <a href="https://jira.whamcloud.com/browse/LU-7543" title="reserve lock flags for upcoming features and future expansion" class="issue-link" data-issue-key="LU-7543"><del>LU-7543</del></a> obd: reserve connection flag OBD_CONNECT_OBDOPACK<br/> Project: fs/lustre-release<br/> Branch: master<br/> Current Patch Set: 1<br/> Commit: 4cbe3cfb592ff71fbf167d40137b4d281e8d9921</p> <p>Fan Yong (fan.yong@intel.com) uploaded a new patch: <a href="http://review.whamcloud.com/17646" class="external-link" target="_blank" rel="nofollow noopener">http://review.whamcloud.com/17646</a><br/> Subject: <a href="https://jira.whamcloud.com/browse/LU-7543" title="reserve lock flags for upcoming features and future expansion" class="issue-link" data-issue-key="LU-7543"><del>LU-7543</del></a> obd: reserve connection flag OBD_CONNECT_LOCK_AHEAD<br/> Project: fs/lustre-release<br/> Branch: master<br/> Current Patch Set: 1<br/> Commit: 6f4b258acba31e3779f047a1dd7cd668789949bd</p> <p>Fan Yong (fan.yong@intel.com) uploaded a new patch: <a href="http://review.whamcloud.com/17647" class="external-link" target="_blank" rel="nofollow noopener">http://review.whamcloud.com/17647</a><br/> Subject: <a href="https://jira.whamcloud.com/browse/LU-7543" title="reserve lock flags for upcoming features and future expansion" class="issue-link" data-issue-key="LU-7543"><del>LU-7543</del></a> obd: reserve connection flag OBD_CONNECT_FLAGS2<br/> Project: fs/lustre-release<br/> Branch: master<br/> Current Patch Set: 1<br/> Commit: 632a9bfbe51e1c7e947276ee7aff6a1bda03ba80</p> <p>Oleg Drokin (oleg.drokin@intel.com) merged in patch <a href="http://review.whamcloud.com/17644/" class="external-link" target="_blank" rel="nofollow noopener">http://review.whamcloud.com/17644/</a><br/> Subject: <a href="https://jira.whamcloud.com/browse/LU-7543" title="reserve lock flags for upcoming features and future expansion" class="issue-link" data-issue-key="LU-7543"><del>LU-7543</del></a> obd: reserve connection flag OBD_CONNECT_SUBTREE<br/> Project: fs/lustre-release<br/> Branch: master<br/> Current Patch Set: <br/> Commit: 2b16de10d79f930283a1a0dc6e8c9c2a779aae5d</p> <p>Oleg Drokin (oleg.drokin@intel.com) merged in patch <a href="http://review.whamcloud.com/17645/" class="external-link" target="_blank" rel="nofollow noopener">http://review.whamcloud.com/17645/</a><br/> Subject: <a href="https://jira.whamcloud.com/browse/LU-7543" title="reserve lock flags for upcoming features and future expansion" class="issue-link" data-issue-key="LU-7543"><del>LU-7543</del></a> obd: reserve connection flag OBD_CONNECT_OBDOPACK<br/> Project: fs/lustre-release<br/> Branch: master<br/> Current Patch Set: <br/> Commit: c801f497807f45e7e081f0e1ea11037749a60270</p> <p>Oleg Drokin (oleg.drokin@intel.com) merged in patch <a href="http://review.whamcloud.com/17646/" class="external-link" target="_blank" rel="nofollow noopener">http://review.whamcloud.com/17646/</a><br/> Subject: <a href="https://jira.whamcloud.com/browse/LU-7543" title="reserve lock flags for upcoming features and future expansion" class="issue-link" data-issue-key="LU-7543"><del>LU-7543</del></a> obd: reserve connection flag OBD_CONNECT_LOCK_AHEAD<br/> Project: fs/lustre-release<br/> Branch: master<br/> Current Patch Set: <br/> Commit: 20d7508afa3b6f3ac703b4d43e5b1ad0ba782f19</p> <p>Oleg Drokin (oleg.drokin@intel.com) merged in patch <a href="http://review.whamcloud.com/17647/" class="external-link" target="_blank" rel="nofollow noopener">http://review.whamcloud.com/17647/</a><br/> Subject: <a href="https://jira.whamcloud.com/browse/LU-7543" title="reserve lock flags for upcoming features and future expansion" class="issue-link" data-issue-key="LU-7543"><del>LU-7543</del></a> obd: reserve connection flag OBD_CONNECT_FLAGS2<br/> Project: fs/lustre-release<br/> Branch: master<br/> Current Patch Set: <br/> Commit: a5dc6abb06215856dde2d572f7d4c24dddebb718</p> <p>The patches have been landed to master.</p> Related Development Rank 1|hzxvkn: Rank (Obsolete) 9223372036854775807 Severity