1. 25 May, 2016 6 commits
    • Ilya Dryomov's avatar
      libceph: variable-sized ceph_object_id · d30291b9
      Ilya Dryomov authored
      Currently ceph_object_id can hold object names of up to 100
      (CEPH_MAX_OID_NAME_LEN) characters.  This is enough for all use cases,
      expect one - long rbd image names:
      
      - a format 1 header is named "<imgname>.rbd"
      - an object that points to a format 2 header is named "rbd_id.<imgname>"
      
      We operate on these potentially long-named objects during rbd map, and,
      for format 1 images, during header refresh.  (A format 2 header name is
      a small system-generated string.)
      
      Lift this 100 character limit by making ceph_object_id be able to point
      to an externally-allocated string.  Apart from being able to work with
      almost arbitrarily-long named objects, this allows us to reduce the
      size of ceph_object_id from >100 bytes to 64 bytes.
      Signed-off-by: default avatarIlya Dryomov <idryomov@gmail.com>
      d30291b9
    • Ilya Dryomov's avatar
      libceph: change how osd_op_reply message size is calculated · 711da55d
      Ilya Dryomov authored
      For a message pool message, preallocate a page, just like we do for
      osd_op.  For a normal message, take ceph_object_id into account and
      don't bother subtracting CEPH_OSD_SLAB_OPS ceph_osd_ops.
      Signed-off-by: default avatarIlya Dryomov <idryomov@gmail.com>
      711da55d
    • Ilya Dryomov's avatar
      libceph: move message allocation out of ceph_osdc_alloc_request() · 13d1ad16
      Ilya Dryomov authored
      The size of ->r_request and ->r_reply messages depends on the size of
      the object name (ceph_object_id), while the size of ceph_osd_request is
      fixed.  Move message allocation into a separate function that would
      have to be called after ceph_object_id and ceph_object_locator (which
      is also going to become variable in size with RADOS namespaces) have
      been filled in:
      
          req = ceph_osdc_alloc_request(...);
          <fill in req->r_base_oid>
          <fill in req->r_base_oloc>
          ceph_osdc_alloc_messages(req);
      Signed-off-by: default avatarIlya Dryomov <idryomov@gmail.com>
      13d1ad16
    • Ilya Dryomov's avatar
      libceph: grab snapc in ceph_osdc_alloc_request() · 84127282
      Ilya Dryomov authored
      ceph_osdc_build_request() is going away.  Grab snapc and initialize
      ->r_snapid in ceph_osdc_alloc_request().
      Signed-off-by: default avatarIlya Dryomov <idryomov@gmail.com>
      84127282
    • Ilya Dryomov's avatar
      3ed97d63
    • Ilya Dryomov's avatar
      rbd: get/put img_request in rbd_img_request_submit() · 663ae2cc
      Ilya Dryomov authored
      By the time we get to checking for_each_obj_request_safe(img_request)
      terminating condition, all obj_requests may be complete and img_request
      ref, that rbd_img_request_submit() takes away from its caller, may be
      put.  Moving the next_obj_request cursor is then a use-after-free on
      img_request.
      
      It's totally benign, as the value that's read is never used, but
      I think it's still worth fixing.
      
      Cc: Alex Elder <elder@linaro.org>
      Signed-off-by: default avatarIlya Dryomov <idryomov@gmail.com>
      663ae2cc
  2. 15 May, 2016 2 commits
  3. 14 May, 2016 11 commits
  4. 13 May, 2016 17 commits
  5. 12 May, 2016 4 commits
    • Andrea Arcangeli's avatar
      mm: thp: calculate the mapcount correctly for THP pages during WP faults · 6d0a07ed
      Andrea Arcangeli authored
      This will provide fully accuracy to the mapcount calculation in the
      write protect faults, so page pinning will not get broken by false
      positive copy-on-writes.
      
      total_mapcount() isn't the right calculation needed in
      reuse_swap_page(), so this introduces a page_trans_huge_mapcount()
      that is effectively the full accurate return value for page_mapcount()
      if dealing with Transparent Hugepages, however we only use the
      page_trans_huge_mapcount() during COW faults where it strictly needed,
      due to its higher runtime cost.
      
      This also provide at practical zero cost the total_mapcount
      information which is needed to know if we can still relocate the page
      anon_vma to the local vma. If page_trans_huge_mapcount() returns 1 we
      can reuse the page no matter if it's a pte or a pmd_trans_huge
      triggering the fault, but we can only relocate the page anon_vma to
      the local vma->anon_vma if we're sure it's only this "vma" mapping the
      whole THP physical range.
      
      Kirill A. Shutemov discovered the problem with moving the page
      anon_vma to the local vma->anon_vma in a previous version of this
      patch and another problem in the way page_move_anon_rmap() was called.
      
      Andrew Morton discovered that CONFIG_SWAP=n wouldn't build in a
      previous version, because reuse_swap_page must be a macro to call
      page_trans_huge_mapcount from swap.h, so this uses a macro again
      instead of an inline function. With this change at least it's a less
      dangerous usage than it was before, because "page" is used only once
      now, while with the previous code reuse_swap_page(page++) would have
      called page_mapcount on page+1 and it would have increased page twice
      instead of just once.
      
      Dean Luick noticed an uninitialized variable that could result in a
      rmap inefficiency for the non-THP case in a previous version.
      
      Mike Marciniszyn said:
      
      : Our RDMA tests are seeing an issue with memory locking that bisects to
      : commit 61f5d698 ("mm: re-enable THP")
      :
      : The test program registers two rather large MRs (512M) and RDMA
      : writes data to a passive peer using the first and RDMA reads it back
      : into the second MR and compares that data.  The sizes are chosen randomly
      : between 0 and 1024 bytes.
      :
      : The test will get through a few (<= 4 iterations) and then gets a
      : compare error.
      :
      : Tracing indicates the kernel logical addresses associated with the individual
      : pages at registration ARE correct , the data in the "RDMA read response only"
      : packets ARE correct.
      :
      : The "corruption" occurs when the packet crosse two pages that are not physically
      : contiguous.   The second page reads back as zero in the program.
      :
      : It looks like the user VA at the point of the compare error no longer points to
      : the same physical address as was registered.
      :
      : This patch totally resolves the issue!
      
      Link: http://lkml.kernel.org/r/1462547040-1737-2-git-send-email-aarcange@redhat.comSigned-off-by: default avatarAndrea Arcangeli <aarcange@redhat.com>
      Reviewed-by: default avatar"Kirill A. Shutemov" <kirill@shutemov.name>
      Reviewed-by: default avatarDean Luick <dean.luick@intel.com>
      Tested-by: default avatarAlex Williamson <alex.williamson@redhat.com>
      Tested-by: default avatarMike Marciniszyn <mike.marciniszyn@intel.com>
      Tested-by: default avatarJosh Collier <josh.d.collier@intel.com>
      Cc: Marc Haber <mh+linux-kernel@zugschlus.de>
      Cc: <stable@vger.kernel.org>	[4.5]
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      6d0a07ed
    • Zhou Chengming's avatar
      ksm: fix conflict between mmput and scan_get_next_rmap_item · 7496fea9
      Zhou Chengming authored
      A concurrency issue about KSM in the function scan_get_next_rmap_item.
      
      task A (ksmd):				|task B (the mm's task):
      					|
      mm = slot->mm;				|
      down_read(&mm->mmap_sem);		|
      					|
      ...					|
      					|
      spin_lock(&ksm_mmlist_lock);		|
      					|
      ksm_scan.mm_slot go to the next slot;	|
      					|
      spin_unlock(&ksm_mmlist_lock);		|
      					|mmput() ->
      					|	ksm_exit():
      					|
      					|spin_lock(&ksm_mmlist_lock);
      					|if (mm_slot && ksm_scan.mm_slot != mm_slot) {
      					|	if (!mm_slot->rmap_list) {
      					|		easy_to_free = 1;
      					|		...
      					|
      					|if (easy_to_free) {
      					|	mmdrop(mm);
      					|	...
      					|
      					|So this mm_struct may be freed in the mmput().
      					|
      up_read(&mm->mmap_sem);			|
      
      As we can see above, the ksmd thread may access a mm_struct that already
      been freed to the kmem_cache.  Suppose a fork will get this mm_struct from
      the kmem_cache, the ksmd thread then call up_read(&mm->mmap_sem), will
      cause mmap_sem.count to become -1.
      
      As suggested by Andrea Arcangeli, unmerge_and_remove_all_rmap_items has
      the same SMP race condition, so fix it too.  My prev fix in function
      scan_get_next_rmap_item will introduce a different SMP race condition, so
      just invert the up_read/spin_unlock order as Andrea Arcangeli said.
      
      Link: http://lkml.kernel.org/r/1462708815-31301-1-git-send-email-zhouchengming1@huawei.comSigned-off-by: default avatarZhou Chengming <zhouchengming1@huawei.com>
      Suggested-by: default avatarAndrea Arcangeli <aarcange@redhat.com>
      Reviewed-by: default avatarAndrea Arcangeli <aarcange@redhat.com>
      Cc: Hugh Dickins <hughd@google.com>
      Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
      Cc: Vlastimil Babka <vbabka@suse.cz>
      Cc: Geliang Tang <geliangtang@163.com>
      Cc: Minchan Kim <minchan@kernel.org>
      Cc: Hanjun Guo <guohanjun@huawei.com>
      Cc: Ding Tianhong <dingtianhong@huawei.com>
      Cc: Li Bin <huawei.libin@huawei.com>
      Cc: Zhen Lei <thunder.leizhen@huawei.com>
      Cc: Xishi Qiu <qiuxishi@huawei.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      7496fea9
    • Junxiao Bi's avatar
      ocfs2: fix posix_acl_create deadlock · c25a1e06
      Junxiao Bi authored
      Commit 702e5bc6 ("ocfs2: use generic posix ACL infrastructure")
      refactored code to use posix_acl_create.  The problem with this function
      is that it is not mindful of the cluster wide inode lock making it
      unsuitable for use with ocfs2 inode creation with ACLs.  For example,
      when used in ocfs2_mknod, this function can cause deadlock as follows.
      The parent dir inode lock is taken when calling posix_acl_create ->
      get_acl -> ocfs2_iop_get_acl which takes the inode lock again.  This can
      cause deadlock if there is a blocked remote lock request waiting for the
      lock to be downconverted.  And same deadlock happened in ocfs2_reflink.
      This fix is to revert back using ocfs2_init_acl.
      
      Fixes: 702e5bc6 ("ocfs2: use generic posix ACL infrastructure")
      Signed-off-by: default avatarTariq Saeed <tariq.x.saeed@oracle.com>
      Signed-off-by: default avatarJunxiao Bi <junxiao.bi@oracle.com>
      Cc: Mark Fasheh <mfasheh@suse.de>
      Cc: Joel Becker <jlbec@evilplan.org>
      Cc: Joseph Qi <joseph.qi@huawei.com>
      Cc: <stable@vger.kernel.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      c25a1e06
    • Junxiao Bi's avatar
      ocfs2: revert using ocfs2_acl_chmod to avoid inode cluster lock hang · 5ee0fbd5
      Junxiao Bi authored
      Commit 743b5f14 ("ocfs2: take inode lock in ocfs2_iop_set/get_acl()")
      introduced this issue.  ocfs2_setattr called by chmod command holds
      cluster wide inode lock when calling posix_acl_chmod.  This latter
      function in turn calls ocfs2_iop_get_acl and ocfs2_iop_set_acl.  These
      two are also called directly from vfs layer for getfacl/setfacl commands
      and therefore acquire the cluster wide inode lock.  If a remote
      conversion request comes after the first inode lock in ocfs2_setattr,
      OCFS2_LOCK_BLOCKED will be set.  And this will cause the second call to
      inode lock from the ocfs2_iop_get_acl() to block indefinetly.
      
      The deleted version of ocfs2_acl_chmod() calls __posix_acl_chmod() which
      does not call back into the filesystem.  Therefore, we restore
      ocfs2_acl_chmod(), modify it slightly for locking as needed, and use that
      instead.
      
      Fixes: 743b5f14 ("ocfs2: take inode lock in ocfs2_iop_set/get_acl()")
      Signed-off-by: default avatarTariq Saeed <tariq.x.saeed@oracle.com>
      Signed-off-by: default avatarJunxiao Bi <junxiao.bi@oracle.com>
      Cc: Mark Fasheh <mfasheh@suse.de>
      Cc: Joel Becker <jlbec@evilplan.org>
      Cc: Joseph Qi <joseph.qi@huawei.com>
      Cc: <stable@vger.kernel.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      5ee0fbd5