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-6214 Lustre <div class="preformatted panel" style="border-width: 1px;"><div class="preformattedContent panelContent"> <pre># echo XXX &gt; f0 # lfs hsm_archive f0 # lfs hsm_state f0 f0: (0x00000009) exists archived, archive_id:1 # lfs hsm_release f0 # lfs hsm_state f0 f0: (0x0000000d) released exists archived, archive_id:1 # tar --xattr -cf /tmp/f0.tar f0 tar: f0: file changed as we read it # rm f0 # tar --xattr -xf /tmp/f0.tar f0 tar: f0: Cannot write: No data available tar: Exiting with failure status due to previous errors # echo $? 2 # ls f0 # cat f0 cat: f0: No data available </pre> </div></div> <p>It does not matter if --xattr is used during extraction.</p> <div class="preformatted panel" style="border-width: 1px;"><div class="preformattedContent panelContent"> <pre># rm f0 # tar -xf /tmp/f0.tar f0 tar: f0: Cannot write: No data available tar: Exiting with failure status due to previous errors # ls f0 # cat f0 cat: f0: No data available </pre> </div></div> <p>Extraction is creating the file and giving it a trusted.lov xattr which has a released pattern. From strace:</p> <div class="preformatted panel" style="border-width: 1px;"><div class="preformattedContent panelContent"> <pre>mknod("f0", 0600) = 0 setxattr("f0", "trusted.hsm", "\x00\x00\x00\x00\x0d\x00\x00\x00\x01\x00\x00\x00\x00\x00\x0 0\x00\x15\x00\x00\x00\x01\x00\x00\x00", 24, 0) = 0 setxattr("f0", "trusted.link", "\xdf\xf1\xea\x11\x01\x00\x00\x00,\x00\x00\x00\x00\x00\x00\ x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x14\x00\x00\x00\x02\x00\x00\x00\x07\x00\x00\x00\x0 1\x00\x00\x00\x00f0", 44, 0) = 0 setxattr("f0", "trusted.lov", "\xd0\x0b\xd1\x0b\x01\x00\x00\x80\x0f\x00\x00\x00\x00\x00\x0 0\x00\x00\x04\x00\x00\x02\x00\x00\x00\x00\x00\x10\x00\x00\x00\x00\x00", 32, 0) = 0 setxattr("f0", "trusted.lma", "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x04\x00\x00\x02\x00\x0 0\x00\x0f\x00\x00\x00\x00\x00\x00\x00", 24, 0) = 0 open("f0", O_WRONLY|O_CREAT, 0600) = 4 write(4, "XXX\n", 4) = -1 ENODATA (No data available) </pre> </div></div> <div class="preformatted panel" style="border-width: 1px;"><div class="preformattedContent panelContent"> <pre># lfs getstripe f0 f0 lmm_stripe_count: 1 lmm_stripe_size: 1048576 lmm_pattern: 80000001 lmm_layout_gen: 0 lmm_stripe_offset: 0 # getfattr -d -m- f0 # file: f0 trusted.link=0s3/HqEQEAAAAsAAAAAAAAAAAAAAAAAAAAABQAAAACAAAABwAAAAEAAAAAZjA= trusted.lma=0sAAAAAAAAAAAABAAAAgAAABcAAAAAAAAA trusted.lov=0s0AvRCwEAAIAXAAAAAAAAAAAEAAACAAAAAAAQAAAAAAA= </pre> </div></div> <p>The same archive works fine when extracting to an ext4 filesystem.</p> <div class="preformatted panel" style="border-width: 1px;"><div class="preformattedContent panelContent"> <pre># cd /tmp # tar -xf /tmp/f0.tar f0 # cat f0 XXX </pre> </div></div> LU-6214

HSM released files archive with 'tar --xattr -c' cannot be extracted to lustre

Bug Major Resolved Fixed Bruno Faccini John Hammond hsm lov patch tar Thu, 5 Feb 2015 16:56:17 +0000 Wed, 23 Sep 2015 13:07:39 +0000 Wed, 23 Sep 2015 13:07:39 +0000 Lustre 2.7.0 Lustre 2.8.0 0 13 <p>It probably doesn't make sense to expose the RELEASED flag to userspace in this way. I'd think that we want the userspace visible attributes of the file to remain unchanged regardless of whether the file is archived or not.</p> <p>Should we just mask off the RELEASED flag before returning <tt>lustre.lov</tt> to userspace? Should that layout also inherit the default striping from the parent (<a href="https://jira.whamcloud.com/browse/LU-6211" title="getxattr() for {lustre,trusted}.lov on HSM released file returns stripe count 0" class="issue-link" data-issue-key="LU-6211">LU-6211</a>)?</p> <p>I did the following analysis:<br/> 1. Execute the lfs hsm_archive filename. This executes ioctl.<br/> 2. The ioctl triggers the copytool an up call driver<br/> 3. Went through the copytool in lustre/utils/lhsmtool_posix.c<br/> 4. ct_save_stripe and other fuction uses fgetxattr function to retrive the lov_user_md buffer. This buffer contains magic number, pattern, object id, size of stripe, number of stripes offset, layout generation number and unsized array of ost data object.<br/> 5. When hsm_release is called it release the space and only keep pointers.<br/> 6. The file is archived using normal tar with --xattr it calls fgetxattr which save the xattrs. but note that it would not store the stripe information of data objects.<br/> 7. Now in the test case the file is deleted using the lmv_unlink -&gt; ll_unlink -&gt; md_unlink -&gt; mdo_unlink call.<br/> 8. Now we have tar file with corrupted xattrs data which we would like to restore using tar --xattrs -xf file.tar file. This tries to apply the layout map and fails.The file is present in the archive.<br/> 9. If you perform same operation without --xattr it works perfectly fine.<br/> 10. If file is archived, released, tar, restore, untar it does not work because same problem comes while restoring the attributes.<br/> 11. If file is tarred before the release operation it works.<br/> 12. Might be tar is not enabled to read the striping information from file that is already released. </p> <p>Aditya Pandit (aditya.pandit@clogeny.com) uploaded a new patch: <a href="http://review.whamcloud.com/14086" class="external-link" target="_blank" rel="nofollow noopener">http://review.whamcloud.com/14086</a><br/> Subject: <a href="https://jira.whamcloud.com/browse/LU-6214" title="HSM released files archive with &#39;tar --xattr -c&#39; cannot be extracted to lustre" class="issue-link" data-issue-key="LU-6214"><del>LU-6214</del></a>: ignore hsm special xattr for now<br/> Project: fs/lustre-release<br/> Branch: b2_5<br/> Current Patch Set: 1<br/> Commit: 290f638056fc17613b2028b521933eb1f5c86259</p> <p>I looked more closely at the bug and the flow. flow goes like this<br/> tar -&gt; listxattr -&gt; getxattr. Then while restoring using tar, it has all the xattrs with incorrect parameters where it calls create -&gt; setxattr. Here it tries to set the stripe information. I think ideally tar should not be allowed to manipulate the internal structures of lustre because it is not fully aware of lustre. <br/> lustre manipulates the stripe information in ll_setxattr and also exposes attributes in listxattr, getxattr and setxattr. </p> <p>How about we separate extended attributes manipulated by lustre and those that use getxattr/setxattr? Put the implementation of manipulation of setxattr/getxattr as ioctls. lhsmtool_posix would call the ioctl for manipulating the attributes. </p> <p>We can completely filter out the lustre specific attributes in getxattr and setxattr, so that applications like tar would not manipulate lustre specific attributes at all. It would be a normal read,write,getxattr and setxattr operation for tar or any other application that manipulate the xattr. Such applications would only handle the attributes which they have set and not the xattrs of lustre.</p> <p>Being able to backip and restore the stripe parameters with tar is a feature that users asked for. I think the right solution here is to just mask out the "RELEASED" flag from the "lov" xattr when it is set. That avoids the current problem of the new file being marked released when it is being restored, but keeps the ability to backup and restore the file layout. It also makes sense to ignore the HSM xattr as the existing patch 14086 does, but it needs updating as mentioned in the comments there. Also, patches should be submitted to master first. </p> <p>Aditya Pandit (panditadityashreesh@yahoo.com) uploaded a new patch: <a href="http://review.whamcloud.com/16060" class="external-link" target="_blank" rel="nofollow noopener">http://review.whamcloud.com/16060</a><br/> Subject: <a href="https://jira.whamcloud.com/browse/LU-6214" title="HSM released files archive with &#39;tar --xattr -c&#39; cannot be extracted to lustre" class="issue-link" data-issue-key="LU-6214"><del>LU-6214</del></a> llite: HSM released files archive.<br/> Project: fs/lustre-release<br/> Branch: master<br/> Current Patch Set: 1<br/> Commit: a2af454aeb1d501647be4de127ebaf945de7e721</p> <p>Don't forget to abandon #14086.</p> <p>Oleg Drokin (oleg.drokin@intel.com) merged in patch <a href="http://review.whamcloud.com/16060/" class="external-link" target="_blank" rel="nofollow noopener">http://review.whamcloud.com/16060/</a><br/> Subject: <a href="https://jira.whamcloud.com/browse/LU-6214" title="HSM released files archive with &#39;tar --xattr -c&#39; cannot be extracted to lustre" class="issue-link" data-issue-key="LU-6214"><del>LU-6214</del></a> llite: tar restore fails for HSM released files.<br/> Project: fs/lustre-release<br/> Branch: master<br/> Current Patch Set: <br/> Commit: b567f5066b7ca2d15d4f492ec205651c9a63ef98</p> <p>Landed for 2.8</p> Related Development Rank 1|hzx5r3: Rank (Obsolete) 17384 Severity