{"id":111888,"date":"2023-12-01T09:10:14","date_gmt":"2023-12-01T07:10:14","guid":{"rendered":"https:\/\/prohoster.info\/blog\/novosti-interneta\/obnovlenie-openzfs-2-1-14-i-2-2-2-s-ustraneniem-oshibki-privodyashhej-k-povrezhdeniyu-fajlov"},"modified":"2023-12-01T09:10:14","modified_gmt":"2023-12-01T07:10:14","slug":"obnovlenie-openzfs-2-1-14-i-2-2-2-s-ustraneniem-oshibki-privodyashhej-k-povrezhdeniyu-fajlov","status":"publish","type":"post","link":"https:\/\/prohoster.info\/et\/blog\/novosti-interneta\/obnovlenie-openzfs-2-1-14-i-2-2-2-s-ustraneniem-oshibki-privodyashhej-k-povrezhdeniyu-fajlov","title":{"rendered":"OpenZFS 2.1.14 ja 2.2.2 uuendamine, mis k\u00f5rvaldab vea, mis viib failide rikutuks muutumiseni.","gt_translate_keys":[{"key":"rendered","format":"text"}]},"content":{"rendered":"
On OpenZFS 2.1.14 and 2.2.2, which enhance the implementation of the ZFS filesystem for Linux and FreeBSD, corrective releases have been generated. The updates resolve an issue in the dnode cache consistency check code that can lead to data corruption in files containing empty areas when copied after modifications are made. <\/p>\n
Initially, the issue was attempted to be fixed in version 2.2.1, but the solution proved ineffective. The bug remained unnoticed for a long time and began to manifest after changes were made to the 'cp' utility in the coreutils 9.x package. It is believed that in Red Hat Enterprise Linux and distributions based on it, the problem does not manifest, as RHEL 9 uses the coreutils 8.x package with different logic for the 'cp' utility. <\/p>\n
The problem occurs when using file copying utilities that can detect and optimize empty areas in files. Corruption may occur in heavily loaded filesystems when a file is copied if the operation is executed almost immediately after modification and part of the data remains only in the dirty cache and has not yet been flushed to disk. <\/p>\n
To optimize the handling of empty areas in files, OpenZFS, starting from release 0.6.2, supports SEEK_HOLE and SEEK_DATA operations, which allow skipping empty file areas when reading from disk. Recognition of empty areas and preserving information about them occurs only after all remaining cache data associated with the file has been flushed to disk. For initiating a flush in OpenZFS, there is a check that assesses the presence of unsaved data in the cache and performs a forced flush of the information to disk necessary for using SEEK_HOLE and SEEK_DATA. <\/p>\n
Unfortunately, the check turned out to be incomplete, and under certain circumstances, the state of the flush was incorrectly determined, leaving old information about the file's content on the disk if the request fell into a small time window between two data flush operations from the cache. Reading operations that optimize the loading of empty areas at this moment could skip reading part of the data, mistakenly considering it empty, while the program working with the file may have modified the empty areas beforehand. As a result, using the 'cp' utility could lead to creating a copy containing empty areas where there were none in the original file. \n Allikas: opennet.ru<\/a> <\/p>","protected":false,"gt_translate_keys":[{"key":"rendered","format":"html"}]},"excerpt":{"rendered":"