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  1. Lustre
  2. LU-2869

extended attribute cache for Lustre

Details

    • Improvement
    • Resolution: Fixed
    • Minor
    • Lustre 2.5.0
    • None
    • 6935

    Description

      The patch implements an extended attribute cache for
      a Lustre client. It is organized as a write-through
      cache: reads are performed from cache, updates are sent
      synchronously to the MDS. An additional inode bit
      is added to protect the cache.

      The patch itself will be uploaded shortly.

      Attachments

        Issue Links

          is related to

          Bug - A problem which impairs or prevents the functions of the product. LU-3795 replay-single test_58b test_58c: trusted.foo: No such attribute

          • Blocker - Blocks development and/or testing work, production could not run.
          • Resolved

          Bug - A problem which impairs or prevents the functions of the product. LU-3670 some trusted xattrs are not coherent on the client

          • Critical - Crashes, loss of data, severe memory leak.
          • Resolved

          Bug - A problem which impairs or prevents the functions of the product. LU-3669 (mdt_xattr.c:178:mdt_getxattr()) ASSERTION( lu_object_assert_exists(&info->mti_object->mot_obj) ) failed:

          • Blocker - Blocks development and/or testing work, production could not run.
          • Closed

          Bug - A problem which impairs or prevents the functions of the product. LU-549 Add xattr list/value cache on client

          • Minor - Minor loss of function, or other problem where easy workaround is present.
          • Closed

          Improvement - An improvement or enhancement to an existing feature or task. LU-3583 LDLM support for atomic match_or_enqueue operation

          • Minor - Minor loss of function, or other problem where easy workaround is present.
          • Open

          Improvement - An improvement or enhancement to an existing feature or task. LU-10276 Revise what MDS_INODELOCK_XATTR protects

          • Minor - Minor loss of function, or other problem where easy workaround is present.
          • Open

          Improvement - An improvement or enhancement to an existing feature or task. LU-17238 negative xattr cache on client

          • Minor - Minor loss of function, or other problem where easy workaround is present.
          • Open

          Activity

            [LU-2869] extended attribute cache for Lustre
            panda Andrew Perepechko added a comment - - edited

            Besides -ENOENT, due to races an FLXATTRLS user can get an inconsistent list of attribute names and values, which the object never had from another client viewpoint. But since there is no use case for that, the locking can be simply dropped.

            panda Andrew Perepechko added a comment - - edited Besides -ENOENT, due to races an FLXATTRLS user can get an inconsistent list of attribute names and values, which the object never had from another client viewpoint. But since there is no use case for that, the locking can be simply dropped.
            bzzz Alex Zhuravlev added a comment -

            well, if this failure is -ENOENT, then it should be easy to check and skip? on the otherhand we carry this structure for every object in MDT cache. a bit expensive for such a case?

            bzzz Alex Zhuravlev added a comment - well, if this failure is -ENOENT, then it should be easy to check and skip? on the otherhand we carry this structure for every object in MDT cache. a bit expensive for such a case?
            panda Andrew Perepechko added a comment -

            The semaphore was added to protect the case when the client does not take the XATTR lock and requests FLXATTRALL.
            FLXATTRALL is implemented as getting the list and then getting the values, so setting/removing an xattr in the middle
            can lead to failure. Currently, there is no FLXATTRLS user that does not take the XATTR lock, so there is no use
            case for the semaphore being contended.

            panda Andrew Perepechko added a comment - The semaphore was added to protect the case when the client does not take the XATTR lock and requests FLXATTRALL. FLXATTRALL is implemented as getting the list and then getting the values, so setting/removing an xattr in the middle can lead to failure. Currently, there is no FLXATTRLS user that does not take the XATTR lock, so there is no use case for the semaphore being contended.
            bzzz Alex Zhuravlev added a comment -

            can you explain why mot_xattr_sem is needed, please?

            bzzz Alex Zhuravlev added a comment - can you explain why mot_xattr_sem is needed, please?
            jamesanunez James Nunez (Inactive) added a comment -

            Landed for 2.5

            jamesanunez James Nunez (Inactive) added a comment - Landed for 2.5
            panda Andrew Perepechko added a comment -

            Thanks, James!

            panda Andrew Perepechko added a comment - Thanks, James!
            jamesanunez James Nunez (Inactive) added a comment -

            The master branch should open for new features soon.

            jamesanunez James Nunez (Inactive) added a comment - The master branch should open for new features soon.
            panda Andrew Perepechko added a comment -

            Will this patch be inspected? It's almost three months from the patch upload. I had to rebase to a recent version.

            panda Andrew Perepechko added a comment - Will this patch be inspected? It's almost three months from the patch upload. I had to rebase to a recent version.
            nrutman Nathan Rutman added a comment -

            Sorry JC, the Xyratex tickets are really only useful for Xyratex engineers. We have posted the patch in the first comment above.

            nrutman Nathan Rutman added a comment - Sorry JC, the Xyratex tickets are really only useful for Xyratex engineers. We have posted the patch in the first comment above.
            jcl jacques-charles lafoucriere added a comment -

            Nathan the xyratex url is broken (server not found error), can you put a valid/public one ?

            jcl jacques-charles lafoucriere added a comment - Nathan the xyratex url is broken (server not found error), can you put a valid/public one ?
            nrutman Nathan Rutman added a comment -

            Xyratex MRP-57

            nrutman Nathan Rutman added a comment - Xyratex MRP-57

            People

              jamesanunez James Nunez (Inactive)
              panda Andrew Perepechko
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              Dates

                Created:
                Updated:
                Resolved: