1. 30 Jan, 2016 5 commits
    • Dan Williams's avatar
      block: use DAX for partition table reads · d1a5f2b4
      Dan Williams authored
      Avoid populating pagecache when the block device is in DAX mode.
      Otherwise these page cache entries collide with the fsync/msync
      implementation and break data durability guarantees.
      
      Cc: Jan Kara <jack@suse.com>
      Cc: Jeff Moyer <jmoyer@redhat.com>
      Cc: Christoph Hellwig <hch@lst.de>
      Cc: Dave Chinner <david@fromorbit.com>
      Cc: Andrew Morton <akpm@linux-foundation.org>
      Reported-by: default avatarRoss Zwisler <ross.zwisler@linux.intel.com>
      Tested-by: default avatarRoss Zwisler <ross.zwisler@linux.intel.com>
      Reviewed-by: default avatarMatthew Wilcox <willy@linux.intel.com>
      Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
      d1a5f2b4
    • Dan Williams's avatar
      block: revert runtime dax control of the raw block device · 9f4736fe
      Dan Williams authored
      Dynamically enabling DAX requires that the page cache first be flushed
      and invalidated.  This must occur atomically with the change of DAX mode
      otherwise we confuse the fsync/msync tracking and violate data
      durability guarantees.  Eliminate the possibilty of DAX-disabled to
      DAX-enabled transitions for now and revisit this for the next cycle.
      
      Cc: Jan Kara <jack@suse.com>
      Cc: Jeff Moyer <jmoyer@redhat.com>
      Cc: Christoph Hellwig <hch@lst.de>
      Cc: Dave Chinner <david@fromorbit.com>
      Cc: Matthew Wilcox <willy@linux.intel.com>
      Cc: Andrew Morton <akpm@linux-foundation.org>
      Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
      Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
      9f4736fe
    • Dan Williams's avatar
      fs, block: force direct-I/O for dax-enabled block devices · 65f87ee7
      Dan Williams authored
      Similar to the file I/O path, re-direct all I/O to the DAX path for I/O
      to a block-device special file.  Both regular files and device special
      files can use the common filp->f_mapping->host lookup to determing is
      DAX is enabled.
      
      Otherwise, we confuse the DAX code that does not expect to find live
      data in the page cache:
      
          ------------[ cut here ]------------
          WARNING: CPU: 0 PID: 7676 at mm/filemap.c:217
          __delete_from_page_cache+0x9f6/0xb60()
          Modules linked in:
          CPU: 0 PID: 7676 Comm: a.out Not tainted 4.4.0+ #276
          Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
           00000000ffffffff ffff88006d3f7738 ffffffff82999e2d 0000000000000000
           ffff8800620a0000 ffffffff86473d20 ffff88006d3f7778 ffffffff81352089
           ffffffff81658d36 ffffffff86473d20 00000000000000d9 ffffea0000009d60
          Call Trace:
           [<     inline     >] __dump_stack lib/dump_stack.c:15
           [<ffffffff82999e2d>] dump_stack+0x6f/0xa2 lib/dump_stack.c:50
           [<ffffffff81352089>] warn_slowpath_common+0xd9/0x140 kernel/panic.c:482
           [<ffffffff813522b9>] warn_slowpath_null+0x29/0x30 kernel/panic.c:515
           [<ffffffff81658d36>] __delete_from_page_cache+0x9f6/0xb60 mm/filemap.c:217
           [<ffffffff81658fb2>] delete_from_page_cache+0x112/0x200 mm/filemap.c:244
           [<ffffffff818af369>] __dax_fault+0x859/0x1800 fs/dax.c:487
           [<ffffffff8186f4f6>] blkdev_dax_fault+0x26/0x30 fs/block_dev.c:1730
           [<     inline     >] wp_pfn_shared mm/memory.c:2208
           [<ffffffff816e9145>] do_wp_page+0xc85/0x14f0 mm/memory.c:2307
           [<     inline     >] handle_pte_fault mm/memory.c:3323
           [<     inline     >] __handle_mm_fault mm/memory.c:3417
           [<ffffffff816ecec3>] handle_mm_fault+0x2483/0x4640 mm/memory.c:3446
           [<ffffffff8127eff6>] __do_page_fault+0x376/0x960 arch/x86/mm/fault.c:1238
           [<ffffffff8127f738>] trace_do_page_fault+0xe8/0x420 arch/x86/mm/fault.c:1331
           [<ffffffff812705c4>] do_async_page_fault+0x14/0xd0 arch/x86/kernel/kvm.c:264
           [<ffffffff86338f78>] async_page_fault+0x28/0x30 arch/x86/entry/entry_64.S:986
           [<ffffffff86336c36>] entry_SYSCALL_64_fastpath+0x16/0x7a
          arch/x86/entry/entry_64.S:185
          ---[ end trace dae21e0f85f1f98c ]---
      
      Fixes: 5a023cdb ("block: enable dax for raw block devices")
      Reported-by: default avatarDmitry Vyukov <dvyukov@google.com>
      Reported-by: default avatarKirill A. Shutemov <kirill@shutemov.name>
      Suggested-by: default avatarJan Kara <jack@suse.cz>
      Reviewed-by: default avatarJan Kara <jack@suse.cz>
      Suggested-by: default avatarMatthew Wilcox <willy@linux.intel.com>
      Tested-by: default avatarRoss Zwisler <ross.zwisler@linux.intel.com>
      Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
      65f87ee7
    • Dan Williams's avatar
      devm_memremap_pages: fix vmem_altmap lifetime + alignment handling · eb7d78c9
      Dan Williams authored
      to_vmem_altmap() needs to return valid results until
      arch_remove_memory() completes.  It also needs to be valid for any pfn
      in a section regardless of whether that pfn maps to data.  This escape
      was a result of a bug in the unit test.
      
      The signature of this bug is that free_pagetable() fails to retrieve a
      vmem_altmap and goes off into the weeds:
      
       BUG: unable to handle kernel NULL pointer dereference at           (null)
       IP: [<ffffffff811d2629>] get_pfnblock_flags_mask+0x49/0x60
       [..]
       Call Trace:
        [<ffffffff811d3477>] free_hot_cold_page+0x97/0x1d0
        [<ffffffff811d367a>] __free_pages+0x2a/0x40
        [<ffffffff8191e669>] free_pagetable+0x8c/0xd4
        [<ffffffff8191ef4e>] remove_pagetable+0x37a/0x808
        [<ffffffff8191b210>] vmemmap_free+0x10/0x20
      
      Fixes: 4b94ffdc ("x86, mm: introduce vmem_altmap to augment vmemmap_populate()")
      Cc: Andrew Morton <akpm@linux-foundation.org>
      Reported-by: default avatarJeff Moyer <jmoyer@redhat.com>
      Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
      eb7d78c9
    • Dan Williams's avatar
      libnvdimm, pfn: fix restoring memmap location · 45eb570a
      Dan Williams authored
      This path was missed when turning on the memmap in pmem support.  Permit
      'pmem' as a valid location for the map.
      Reported-by: default avatarJeff Moyer <jmoyer@redhat.com>
      Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
      45eb570a
  2. 26 Jan, 2016 1 commit
  3. 24 Jan, 2016 34 commits