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Lisheng Sun edited comment on HADOOP-16112 at 6/10/19 8:15 AM: --------------------------------------------------------------- [~hexiaoqiao]Thanks for watching this issue. The issue is a race condition in TrashPolicyDefault#moveToTrash. {code:java} try { if (!fs.mkdirs(baseTrashPath, PERMISSION)) { // create current LOG.warn("Can't create(mkdir) trash directory: " + baseTrashPath); return false; } } catch (FileAlreadyExistsException e) { // find the path which is not a directory, and modify baseTrashPath // & trashPath, then mkdirs Path existsFilePath = baseTrashPath; while (!fs.exists(existsFilePath)) { existsFilePath = existsFilePath.getParent(); } baseTrashPath = new Path(baseTrashPath.toString().replace( existsFilePath.toString(), existsFilePath.toString() + Time.now()) ); trashPath = new Path(baseTrashPath, trashPath.getName()); // retry, ignore current failure --i; continue; } catch (IOException e) { LOG.warn("Can't create trash directory: " + baseTrashPath, e); cause = e; break; } try { // if the target path in Trash already exists, then append with // a current time in millisecs. String orig = trashPath.toString(); while(fs.exists(trashPath)) { trashPath = new Path(orig + Time.now()); } // move to current trash fs.rename(path, trashPath, Rename.TO_TRASH); LOG.info("Moved: '" + path + "' to trash at: " + trashPath); return true; } catch (IOException e) { cause = e; } {code} when run the following code, the other thread deletes the existsFilePath simultaneously, the results doesn't meet expectation. {code:java} Path existsFilePath = baseTrashPath; while (!fs.exists(existsFilePath)) { existsFilePath = existsFilePath.getParent(); }{code} According to current code, the result is: {code:java} there is /user/u_sunlisheng/.Trash/Current/user/u_sunlisheng/b //existFilePath when delete /user/u_sunlisheng/b/a. if existsFilePath is deleted, the result is /user/u_sunlisheng/.Trash/Current/user/u_sunlisheng+timstamp/b/a so when existsFilePath is deleted, don't modify baseTrashPath. {code} Please correct me if i am wrong. was (Author: leosun08): Thanks for watching this issue. The issue is a race condition in TrashPolicyDefault#moveToTrash. try { if (!fs.mkdirs(baseTrashPath, PERMISSION)) { // create current LOG.warn("Can't create(mkdir) trash directory: " + baseTrashPath); return false; } } catch (FileAlreadyExistsException e) { // find the path which is not a directory, and modify baseTrashPath // & trashPath, then mkdirs Path existsFilePath = baseTrashPath; while (!fs.exists(existsFilePath)) { existsFilePath = existsFilePath.getParent(); } baseTrashPath = new Path(baseTrashPath.toString().replace( existsFilePath.toString(), existsFilePath.toString() + Time.now()) ); trashPath = new Path(baseTrashPath, trashPath.getName()); // retry, ignore current failure --i; continue; } catch (IOException e) { LOG.warn("Can't create trash directory: " + baseTrashPath, e); cause = e; break; } try { // if the target path in Trash already exists, then append with // a current time in millisecs. String orig = trashPath.toString(); while(fs.exists(trashPath)) { trashPath = new Path(orig + Time.now()); } // move to current trash fs.rename(path, trashPath, Rename.TO_TRASH); LOG.info("Moved: '" + path + "' to trash at: " + trashPath); return true; } catch (IOException e) { cause = e; } > Delete the baseTrashPath's subDir leads to don't modify baseTrashPath > --------------------------------------------------------------------- > > Key: HADOOP-16112 > URL: https://issues.apache.org/jira/browse/HADOOP-16112 > Project: Hadoop Common > Issue Type: Bug > Components: common > Affects Versions: 3.2.0 > Reporter: Lisheng Sun > Priority: Major > Attachments: HADOOP-16112.001.patch, HADOOP-16112.002.patch > > > There is race condition in TrashPolicyDefault#moveToTrash > try { > if (!fs.mkdirs(baseTrashPath, PERMISSION)) > { // create current LOG.warn("Can't create(mkdir) trash directory: " + > baseTrashPath); return false; } > } catch (FileAlreadyExistsException e) { > // find the path which is not a directory, and modify baseTrashPath > // & trashPath, then mkdirs > Path existsFilePath = baseTrashPath; > while (!fs.exists(existsFilePath)) > { existsFilePath = existsFilePath.getParent(); } > {color:#ff0000}// case{color} > {color:#ff0000} other thread deletes existsFilePath here ,the results > doesn't meet expectation{color} > {color:#ff0000} for example{color} > {color:#ff0000} there is > /user/u_sunlisheng/.Trash/Current/user/u_sunlisheng/b{color} > {color:#ff0000} when delete /user/u_sunlisheng/b/a. if existsFilePath is > deleted, the result is > /user/u_sunlisheng/.Trash/Current/user/u_sunlisheng+timstamp/b/a{color} > {color:#ff0000} so when existsFilePath is deleted, don't modify > baseTrashPath. {color} > baseTrashPath = new Path(baseTrashPath.toString().replace( > existsFilePath.toString(), existsFilePath.toString() + Time.now()) > ); > trashPath = new Path(baseTrashPath, trashPath.getName()); > // retry, ignore current failure > --i; > continue; > } catch (IOException e) > { LOG.warn("Can't create trash directory: " + baseTrashPath, e); cause = e; > break; } -- This message was sent by Atlassian JIRA (v7.6.3#76005) --------------------------------------------------------------------- To unsubscribe, e-mail: common-issues-unsubscr...@hadoop.apache.org For additional commands, e-mail: common-issues-h...@hadoop.apache.org