【OLK-5.10】ext4长稳测试正常下发IO时出现readonly

【严重程度】 严重
【特性】 文件系统
【重现类型】 有条件必然重现
【* 定位分析】http://openeuler.huawei.com/bugzilla/show_bug.cgi?id=187870</p><div class="ql-code-block-container" spellcheck="false"><div class="ql-code-block" data-language="plain">// 问题场景</div><div class="ql-code-block" data-language="plain">page size和block size不同情况下并发读写同一个page不同block（进程1写当前page的buffer2，进程2读当前page的buffer1）；</div><div class="ql-code-block" data-language="plain">写进程只写page中的一个block，但会遍历所有block，当遍历到不需要写的block时，先获取buffer锁（进程1获取buffer1锁），不做任何操作再释放。在获取和释放之间，若此时读进程刚好尝试获取该buffer锁，则失败，在写进程释放锁后，读进程返回-EIO（buffer1没有被读写，没有标记为uptodate）</div><div class="ql-code-block" data-language="plain"><br></div><div class="ql-code-block" data-language="plain">// 写进程栈</div><div class="ql-code-block" data-language="plain">wb_workfn</div><div class="ql-code-block" data-language="plain"> wb_do_writeback</div><div class="ql-code-block" data-language="plain">  wb_writeback</div><div class="ql-code-block" data-language="plain">   __writeback_inodes_wb</div><div class="ql-code-block" data-language="plain">    writeback_sb_inodes</div><div class="ql-code-block" data-language="plain">	 __writeback_single_inode</div><div class="ql-code-block" data-language="plain">	  do_writepages</div><div class="ql-code-block" data-language="plain">	   blkdev_writepages // mapping-&gt;a_ops-&gt;writepages(mapping, wbc)</div><div class="ql-code-block" data-language="plain">	    generic_writepages</div><div class="ql-code-block" data-language="plain">		 write_cache_pages</div><div class="ql-code-block" data-language="plain">		  __writepage // (*writepage)(page, wbc, data);</div><div class="ql-code-block" data-language="plain">		   blkdev_writepage // mapping-&gt;a_ops-&gt;writepage</div><div class="ql-code-block" data-language="plain">		    block_write_full_page</div><div class="ql-code-block" data-language="plain">			 __block_write_full_page</div><div class="ql-code-block" data-language="plain">			  trylock_buffer // 时间点1</div><div class="ql-code-block" data-language="plain">			  // if (test_clear_buffer_dirty(bh)) { mark_buffer_async_write_endio(bh, handler); }</div><div class="ql-code-block" data-language="plain">			  unlock_buffer // 时间点2</div><div class="ql-code-block" data-language="plain"><br></div><div class="ql-code-block" data-language="plain">// 读进程栈</div><div class="ql-code-block" data-language="plain">do_sys_open</div><div class="ql-code-block" data-language="plain"> do_sys_openat2</div><div class="ql-code-block" data-language="plain">  do_filp_open</div><div class="ql-code-block" data-language="plain">   path_openat</div><div class="ql-code-block" data-language="plain">    open_last_lookups</div><div class="ql-code-block" data-language="plain">	 lookup_open</div><div class="ql-code-block" data-language="plain">	  ext4_create// dir_inode-&gt;i_op-&gt;create</div><div class="ql-code-block" data-language="plain">	   ext4_new_inode_start_handle</div><div class="ql-code-block" data-language="plain">	    __ext4_new_inode</div><div class="ql-code-block" data-language="plain">		 ext4_xattr_credits_for_new_inode</div><div class="ql-code-block" data-language="plain">		  get_acl</div><div class="ql-code-block" data-language="plain">		   ext4_get_acl // inode-&gt;i_op-&gt;get_acl</div><div class="ql-code-block" data-language="plain">		    ext4_xattr_get</div><div class="ql-code-block" data-language="plain">			 ext4_xattr_block_get</div><div class="ql-code-block" data-language="plain">			  ext4_sb_bread</div><div class="ql-code-block" data-language="plain">			   __ext4_sb_bread_gfp</div><div class="ql-code-block" data-language="plain">			    ext4_read_bh_lock</div><div class="ql-code-block" data-language="plain">				 trylock_buffer // 时间点1与时间点2之间，获取锁失败</div><div class="ql-code-block" data-language="plain">				 // return -EIO; // 未检测到buffer_head状态为uptodate，返回-EIO</div></div><p>
【* 影响评估及测试建议】无</p><p>
【* 对外影响描述】无</p><p>

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