1. 14 5月, 2015 2 次提交
  2. 13 5月, 2015 1 次提交
  3. 07 5月, 2015 1 次提交
  4. 06 5月, 2015 2 次提交
  5. 05 5月, 2015 1 次提交
    • S
      blk-mq: fix FUA request hang · b2387ddc
      Shaohua Li 提交于
      When a FUA request enters its DATA stage of flush pipeline, the
      request is added to mq requeue list, the request will then be added to
      ctx->rq_list. blk_mq_attempt_merge() might merge the request with a bio.
      Later when the request is finished the flush pipeline, the
      request->__data_len is 0. Then I only saw the bio gets endio called, the
      original request never finish.
      
      Adding REQ_FLUSH_SEQ into REQ_NOMERGE_FLAGS looks an easy fix.
      
      stable: 3.15+
      Signed-off-by: NShaohua Li <shli@fb.com>
      Signed-off-by: NJens Axboe <axboe@fb.com>
      b2387ddc
  6. 04 5月, 2015 1 次提交
    • D
      lib: make memzero_explicit more robust against dead store elimination · 7829fb09
      Daniel Borkmann 提交于
      In commit 0b053c95 ("lib: memzero_explicit: use barrier instead
      of OPTIMIZER_HIDE_VAR"), we made memzero_explicit() more robust in
      case LTO would decide to inline memzero_explicit() and eventually
      find out it could be elimiated as dead store.
      
      While using barrier() works well for the case of gcc, recent efforts
      from LLVMLinux people suggest to use llvm as an alternative to gcc,
      and there, Stephan found in a simple stand-alone user space example
      that llvm could nevertheless optimize and thus elimitate the memset().
      A similar issue has been observed in the referenced llvm bug report,
      which is regarded as not-a-bug.
      
      Based on some experiments, icc is a bit special on its own, while it
      doesn't seem to eliminate the memset(), it could do so with an own
      implementation, and then result in similar findings as with llvm.
      
      The fix in this patch now works for all three compilers (also tested
      with more aggressive optimization levels). Arguably, in the current
      kernel tree it's more of a theoretical issue, but imho, it's better
      to be pedantic about it.
      
      It's clearly visible with gcc/llvm though, with the below code: if we
      would have used barrier() only here, llvm would have omitted clearing,
      not so with barrier_data() variant:
      
        static inline void memzero_explicit(void *s, size_t count)
        {
          memset(s, 0, count);
          barrier_data(s);
        }
      
        int main(void)
        {
          char buff[20];
          memzero_explicit(buff, sizeof(buff));
          return 0;
        }
      
        $ gcc -O2 test.c
        $ gdb a.out
        (gdb) disassemble main
        Dump of assembler code for function main:
         0x0000000000400400  <+0>: lea   -0x28(%rsp),%rax
         0x0000000000400405  <+5>: movq  $0x0,-0x28(%rsp)
         0x000000000040040e <+14>: movq  $0x0,-0x20(%rsp)
         0x0000000000400417 <+23>: movl  $0x0,-0x18(%rsp)
         0x000000000040041f <+31>: xor   %eax,%eax
         0x0000000000400421 <+33>: retq
        End of assembler dump.
      
        $ clang -O2 test.c
        $ gdb a.out
        (gdb) disassemble main
        Dump of assembler code for function main:
         0x00000000004004f0  <+0>: xorps  %xmm0,%xmm0
         0x00000000004004f3  <+3>: movaps %xmm0,-0x18(%rsp)
         0x00000000004004f8  <+8>: movl   $0x0,-0x8(%rsp)
         0x0000000000400500 <+16>: lea    -0x18(%rsp),%rax
         0x0000000000400505 <+21>: xor    %eax,%eax
         0x0000000000400507 <+23>: retq
        End of assembler dump.
      
      As gcc, clang, but also icc defines __GNUC__, it's sufficient to define
      this in compiler-gcc.h only to be picked up. For a fallback or otherwise
      unsupported compiler, we define it as a barrier. Similarly, for ecc which
      does not support gcc inline asm.
      
      Reference: https://llvm.org/bugs/show_bug.cgi?id=15495Reported-by: NStephan Mueller <smueller@chronox.de>
      Tested-by: NStephan Mueller <smueller@chronox.de>
      Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
      Cc: Theodore Ts'o <tytso@mit.edu>
      Cc: Stephan Mueller <smueller@chronox.de>
      Cc: Hannes Frederic Sowa <hannes@stressinduktion.org>
      Cc: mancha security <mancha1@zoho.com>
      Cc: Mark Charlebois <charlebm@gmail.com>
      Cc: Behan Webster <behanw@converseincode.com>
      Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>
      7829fb09
  7. 30 4月, 2015 1 次提交
    • N
      bridge/nl: remove wrong use of NLM_F_MULTI · 46c264da
      Nicolas Dichtel 提交于
      NLM_F_MULTI must be used only when a NLMSG_DONE message is sent. In fact,
      it is sent only at the end of a dump.
      
      Libraries like libnl will wait forever for NLMSG_DONE.
      
      Fixes: e5a55a89 ("net: create generic bridge ops")
      Fixes: 815cccbf ("ixgbe: add setlink, getlink support to ixgbe and ixgbevf")
      CC: John Fastabend <john.r.fastabend@intel.com>
      CC: Sathya Perla <sathya.perla@emulex.com>
      CC: Subbu Seetharaman <subbu.seetharaman@emulex.com>
      CC: Ajit Khaparde <ajit.khaparde@emulex.com>
      CC: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
      CC: intel-wired-lan@lists.osuosl.org
      CC: Jiri Pirko <jiri@resnulli.us>
      CC: Scott Feldman <sfeldma@gmail.com>
      CC: Stephen Hemminger <stephen@networkplumber.org>
      CC: bridge@lists.linux-foundation.org
      Signed-off-by: NNicolas Dichtel <nicolas.dichtel@6wind.com>
      Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      46c264da
  8. 28 4月, 2015 2 次提交
  9. 27 4月, 2015 1 次提交
  10. 26 4月, 2015 1 次提交
    • E
      net: fix crash in build_skb() · 2ea2f62c
      Eric Dumazet 提交于
      When I added pfmemalloc support in build_skb(), I forgot netlink
      was using build_skb() with a vmalloc() area.
      
      In this patch I introduce __build_skb() for netlink use,
      and build_skb() is a wrapper handling both skb->head_frag and
      skb->pfmemalloc
      
      This means netlink no longer has to hack skb->head_frag
      
      [ 1567.700067] kernel BUG at arch/x86/mm/physaddr.c:26!
      [ 1567.700067] invalid opcode: 0000 [#1] PREEMPT SMP KASAN
      [ 1567.700067] Dumping ftrace buffer:
      [ 1567.700067]    (ftrace buffer empty)
      [ 1567.700067] Modules linked in:
      [ 1567.700067] CPU: 9 PID: 16186 Comm: trinity-c182 Not tainted 4.0.0-next-20150424-sasha-00037-g4796e21 #2167
      [ 1567.700067] task: ffff880127efb000 ti: ffff880246770000 task.ti: ffff880246770000
      [ 1567.700067] RIP: __phys_addr (arch/x86/mm/physaddr.c:26 (discriminator 3))
      [ 1567.700067] RSP: 0018:ffff8802467779d8  EFLAGS: 00010202
      [ 1567.700067] RAX: 000041000ed8e000 RBX: ffffc9008ed8e000 RCX: 000000000000002c
      [ 1567.700067] RDX: 0000000000000004 RSI: 0000000000000000 RDI: ffffffffb3fd6049
      [ 1567.700067] RBP: ffff8802467779f8 R08: 0000000000000019 R09: ffff8801d0168000
      [ 1567.700067] R10: ffff8801d01680c7 R11: ffffed003a02d019 R12: ffffc9000ed8e000
      [ 1567.700067] R13: 0000000000000f40 R14: 0000000000001180 R15: ffffc9000ed8e000
      [ 1567.700067] FS:  00007f2a7da3f700(0000) GS:ffff8801d1000000(0000) knlGS:0000000000000000
      [ 1567.700067] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
      [ 1567.700067] CR2: 0000000000738308 CR3: 000000022e329000 CR4: 00000000000007e0
      [ 1567.700067] Stack:
      [ 1567.700067]  ffffc9000ed8e000 ffff8801d0168000 ffffc9000ed8e000 ffff8801d0168000
      [ 1567.700067]  ffff880246777a28 ffffffffad7c0a21 0000000000001080 ffff880246777c08
      [ 1567.700067]  ffff88060d302e68 ffff880246777b58 ffff880246777b88 ffffffffad9a6821
      [ 1567.700067] Call Trace:
      [ 1567.700067] build_skb (include/linux/mm.h:508 net/core/skbuff.c:316)
      [ 1567.700067] netlink_sendmsg (net/netlink/af_netlink.c:1633 net/netlink/af_netlink.c:2329)
      [ 1567.774369] ? sched_clock_cpu (kernel/sched/clock.c:311)
      [ 1567.774369] ? netlink_unicast (net/netlink/af_netlink.c:2273)
      [ 1567.774369] ? netlink_unicast (net/netlink/af_netlink.c:2273)
      [ 1567.774369] sock_sendmsg (net/socket.c:614 net/socket.c:623)
      [ 1567.774369] sock_write_iter (net/socket.c:823)
      [ 1567.774369] ? sock_sendmsg (net/socket.c:806)
      [ 1567.774369] __vfs_write (fs/read_write.c:479 fs/read_write.c:491)
      [ 1567.774369] ? get_lock_stats (kernel/locking/lockdep.c:249)
      [ 1567.774369] ? default_llseek (fs/read_write.c:487)
      [ 1567.774369] ? vtime_account_user (kernel/sched/cputime.c:701)
      [ 1567.774369] ? rw_verify_area (fs/read_write.c:406 (discriminator 4))
      [ 1567.774369] vfs_write (fs/read_write.c:539)
      [ 1567.774369] SyS_write (fs/read_write.c:586 fs/read_write.c:577)
      [ 1567.774369] ? SyS_read (fs/read_write.c:577)
      [ 1567.774369] ? __this_cpu_preempt_check (lib/smp_processor_id.c:63)
      [ 1567.774369] ? trace_hardirqs_on_caller (kernel/locking/lockdep.c:2594 kernel/locking/lockdep.c:2636)
      [ 1567.774369] ? trace_hardirqs_on_thunk (arch/x86/lib/thunk_64.S:42)
      [ 1567.774369] system_call_fastpath (arch/x86/kernel/entry_64.S:261)
      
      Fixes: 79930f58 ("net: do not deplete pfmemalloc reserve")
      Signed-off-by: NEric Dumazet <edumazet@google.com>
      Reported-by: NSasha Levin <sasha.levin@oracle.com>
      Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      2ea2f62c
  11. 25 4月, 2015 4 次提交
    • E
      fix I_DIO_WAKEUP definition · ac74d8d6
      Eric Sandeen 提交于
      I_DIO_WAKEUP is never directly used, but fix it up anyway.
      Signed-off-by: NEric Sandeen <sandeen@redhat.com>
      Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
      ac74d8d6
    • J
      direct-io: only inc/dec inode->i_dio_count for file systems · fe0f07d0
      Jens Axboe 提交于
      do_blockdev_direct_IO() increments and decrements the inode
      ->i_dio_count for each IO operation. It does this to protect against
      truncate of a file. Block devices don't need this sort of protection.
      
      For a capable multiqueue setup, this atomic int is the only shared
      state between applications accessing the device for O_DIRECT, and it
      presents a scaling wall for that. In my testing, as much as 30% of
      system time is spent incrementing and decrementing this value. A mixed
      read/write workload improved from ~2.5M IOPS to ~9.6M IOPS, with
      better latencies too. Before:
      
      clat percentiles (usec):
       |  1.00th=[   33],  5.00th=[   34], 10.00th=[   34], 20.00th=[   34],
       | 30.00th=[   34], 40.00th=[   34], 50.00th=[   35], 60.00th=[   35],
       | 70.00th=[   35], 80.00th=[   35], 90.00th=[   37], 95.00th=[   80],
       | 99.00th=[   98], 99.50th=[  151], 99.90th=[  155], 99.95th=[  155],
       | 99.99th=[  165]
      
      After:
      
      clat percentiles (usec):
       |  1.00th=[   95],  5.00th=[  108], 10.00th=[  129], 20.00th=[  149],
       | 30.00th=[  155], 40.00th=[  161], 50.00th=[  167], 60.00th=[  171],
       | 70.00th=[  177], 80.00th=[  185], 90.00th=[  201], 95.00th=[  270],
       | 99.00th=[  390], 99.50th=[  398], 99.90th=[  418], 99.95th=[  422],
       | 99.99th=[  438]
      
      In other setups, Robert Elliott reported seeing good performance
      improvements:
      
      https://lkml.org/lkml/2015/4/3/557
      
      The more applications accessing the device, the worse it gets.
      
      Add a new direct-io flags, DIO_SKIP_DIO_COUNT, which tells
      do_blockdev_direct_IO() that it need not worry about incrementing
      or decrementing the inode i_dio_count for this caller.
      
      Cc: Andrew Morton <akpm@linux-foundation.org>
      Cc: Christoph Hellwig <hch@lst.de>
      Cc: Theodore Ts'o <tytso@mit.edu>
      Cc: Elliott, Robert (Server Storage) <elliott@hp.com>
      Cc: Al Viro <viro@zeniv.linux.org.uk>
      Signed-off-by: NJens Axboe <axboe@fb.com>
      Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
      fe0f07d0
    • M
      irqchip: gic: Drop support for gic_arch_extn · 1dcc73d7
      Marc Zyngier 提交于
      Now that the users of gic_arch_extn have been fixed, drop the
      "feature" for good. This leads to the removal of some now useless
      locking.
      Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>
      Cc: linux-arm-kernel@lists.infradead.org
      Cc: Jason Cooper <jason@lakedaemon.net>
      Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
      1dcc73d7
    • F
      netfilter: bridge: fix NULL deref in physin/out ifindex helpers · 547c4b54
      Florian Westphal 提交于
      Might not have an outdev yet. We'll oops when iface goes down while skbs
      are still nfqueue'd:
      
      RIP: 0010:[<ffffffff81422a2f>]  [<ffffffff81422a2f>] dev_cmp+0x4f/0x80
      nfqnl_rcv_dev_event+0xe2/0x150
      notifier_call_chain+0x53/0xa0
      
      Fixes: c737b7c4 ("netfilter: bridge: add helpers for fetching physin/outdev")
      Signed-off-by: NFlorian Westphal <fw@strlen.de>
      Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>
      547c4b54
  12. 24 4月, 2015 5 次提交
    • J
      rhashtable: don't attempt to grow when at max_size · 1d8dc3d3
      Johannes Berg 提交于
      The conversion of mac80211's station table to rhashtable had a bug
      that I found by accident in code review, that hadn't been found as
      rhashtable apparently managed to have a maximum hash chain length
      of one (!) in all our testing.
      
      In order to test the bug and verify the fix I set my rhashtable's
      max_size very low (4) in order to force getting hash collisions.
      
      At that point, rhashtable WARNed in rhashtable_insert_rehash() but
      didn't actually reject the hash table insertion. This caused it to
      lose insertions - my master list of stations would have 9 entries,
      but the rhashtable only had 5. This may warrant a deeper look, but
      that WARN_ON() just shouldn't happen.
      
      Fix this by not returning true from rht_grow_above_100() when the
      rhashtable's max_size has been reached - in this case the user is
      explicitly configuring it to be at most that big, so even if it's
      now above 100% it shouldn't attempt to resize.
      
      This fixes the "lost insertion" issue and consequently allows my
      code to display its error (and verify my fix for it.)
      Signed-off-by: NJohannes Berg <johannes.berg@intel.com>
      Acked-by: NThomas Graf <tgraf@suug.ch>
      Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      1d8dc3d3
    • A
      NFS: Move nfs_idmap.h into fs/nfs/ · 40c64c26
      Anna Schumaker 提交于
      This file is only used internally to the NFS v4 module, so it doesn't
      need to be in the global include path.  I also renamed it from
      nfs_idmap.h to nfs4idmap.h to emphasize that it's an NFSv4-only include
      file.
      Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>
      Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>
      40c64c26
    • A
      NFS: Remove CONFIG_NFS_V4 checks from nfs_idmap.h · f9ebd618
      Anna Schumaker 提交于
      The idmapper is completely internal to the NFS v4 module, so this macro
      will always evaluate to true.  This patch also removes unnecessary
      includes of this file from the generic NFS client.
      Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>
      Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>
      f9ebd618
    • J
      sunrpc: make debugfs file creation failure non-fatal · 3f940098
      Jeff Layton 提交于
      v2: gracefully handle the case where some dentry pointers end up NULL
          and be more dilligent about zeroing out dentry pointers
      
      We currently have a problem that SELinux policy is being enforced when
      creating debugfs files. If a debugfs file is created as a side effect of
      doing some syscall, then that creation can fail if the SELinux policy
      for that process prevents it.
      
      This seems wrong. We don't do that for files under /proc, for instance,
      so Bruce has proposed a patch to fix that.
      
      While discussing that patch however, Greg K.H. stated:
      
          "No kernel code should care / fail if a debugfs function fails, so
           please fix up the sunrpc code first."
      
      This patch converts all of the sunrpc debugfs setup code to be void
      return functins, and the callers to not look for errors from those
      functions.
      
      This should allow rpc_clnt and rpc_xprt creation to work, even if the
      kernel fails to create debugfs files for some reason.
      
      Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
      Acked-by: N"J. Bruce Fields" <bfields@fieldses.org>
      Signed-off-by: NJeff Layton <jeff.layton@primarydata.com>
      Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>
      3f940098
    • A
      NFS: Don't zap caches on fallocate() · 9a51940b
      Anna Schumaker 提交于
      This patch adds a GETATTR to the end of ALLOCATE and DEALLOCATE
      operations so we can set the updated inode size and change attribute
      directly.  DEALLOCATE will still need to release pagecache pages, so
      nfs42_proc_deallocate() now calls truncate_pagecache_range() before
      contacting the server.
      Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>
      Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>
      9a51940b
  13. 23 4月, 2015 4 次提交
  14. 22 4月, 2015 7 次提交
    • I
      libceph: announce support for straw2 buckets · 7c1c4747
      Ilya Dryomov 提交于
      Sync up feature bits and enable CEPH_FEATURE_CRUSH_V4.
      Signed-off-by: NIlya Dryomov <idryomov@gmail.com>
      7c1c4747
    • I
      crush: straw2 bucket type with an efficient 64-bit crush_ln() · 958a2765
      Ilya Dryomov 提交于
      This is an improved straw bucket that correctly avoids any data movement
      between items A and B when neither A nor B's weights are changed.  Said
      differently, if we adjust the weight of item C (including adding it anew
      or removing it completely), we will only see inputs move to or from C,
      never between other items in the bucket.
      
      Notably, there is not intermediate scaling factor that needs to be
      calculated.  The mapping function is a simple function of the item weights.
      
      The below commits were squashed together into this one (mostly to avoid
      adding and then yanking a ~6000 lines worth of crush_ln_table):
      
      - crush: add a straw2 bucket type
      - crush: add crush_ln to calculate nature log efficently
      - crush: improve straw2 adjustment slightly
      - crush: change crush_ln to provide 32 more digits
      - crush: fix crush_get_bucket_item_weight and bucket destroy for straw2
      - crush/mapper: fix divide-by-0 in straw2
        (with div64_s64() for draw = ln / w and INT64_MIN -> S64_MIN - need
         to create a proper compat.h in ceph.git)
      
      Reflects ceph.git commits 242293c908e923d474910f2b8203fa3b41eb5a53,
                                32a1ead92efcd351822d22a5fc37d159c65c1338,
                                6289912418c4a3597a11778bcf29ed5415117ad9,
                                35fcb04e2945717cf5cfe150b9fa89cb3d2303a1,
                                6445d9ee7290938de1e4ee9563912a6ab6d8ee5f,
                                b5921d55d16796e12d66ad2c4add7305f9ce2353.
      Signed-off-by: NIlya Dryomov <idryomov@gmail.com>
      958a2765
    • Y
      ceph: rename snapshot support · 0ea611a3
      Yan, Zheng 提交于
      Signed-off-by: NYan, Zheng <zyan@redhat.com>
      0ea611a3
    • S
      perf/x86/intel/uncore: Move PCI IDs for IMC to uncore driver · 0140e614
      Sonny Rao 提交于
      This keeps all the related PCI IDs together in the driver where
      they are used.
      Signed-off-by: NSonny Rao <sonnyrao@chromium.org>
      Acked-by: NBjorn Helgaas <bhelgaas@google.com>
      Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
      Cc: Paul Mackerras <paulus@samba.org>
      Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Stephane Eranian <eranian@google.com>
      Link: http://lkml.kernel.org/r/1429644791-25724-1-git-send-email-sonnyrao@chromium.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>
      0140e614
    • M
      md/raid5: activate raid6 rmw feature · 584acdd4
      Markus Stockhausen 提交于
      Glue it altogehter. The raid6 rmw path should work the same as the
      already existing raid5 logic. So emulate the prexor handling/flags
      and split functions as needed.
      
      1) Enable xor_syndrome() in the async layer.
      
      2) Split ops_run_prexor() into RAID4/5 and RAID6 logic. Xor the syndrome
      at the start of a rmw run as we did it before for the single parity.
      
      3) Take care of rmw run in ops_run_reconstruct6(). Again process only
      the changed pages to get syndrome back into sync.
      
      4) Enhance set_syndrome_sources() to fill NULL pages if we are in a rmw
      run. The lower layers will calculate start & end pages from that and
      call the xor_syndrome() correspondingly.
      
      5) Adapt the several places where we ignored Q handling up to now.
      
      Performance numbers for a single E5630 system with a mix of 10 7200k
      desktop/server disks. 300 seconds random write with 8 threads onto a
      3,2TB (10*400GB) RAID6 64K chunk without spare (group_thread_cnt=4)
      
      bsize   rmw_level=1   rmw_level=0   rmw_level=1   rmw_level=0
              skip_copy=1   skip_copy=1   skip_copy=0   skip_copy=0
         4K      115 KB/s      141 KB/s      165 KB/s      140 KB/s
         8K      225 KB/s      275 KB/s      324 KB/s      274 KB/s
        16K      434 KB/s      536 KB/s      640 KB/s      534 KB/s
        32K      751 KB/s    1,051 KB/s    1,234 KB/s    1,045 KB/s
        64K    1,339 KB/s    1,958 KB/s    2,282 KB/s    1,962 KB/s
       128K    2,673 KB/s    3,862 KB/s    4,113 KB/s    3,898 KB/s
       256K    7,685 KB/s    7,539 KB/s    7,557 KB/s    7,638 KB/s
       512K   19,556 KB/s   19,558 KB/s   19,652 KB/s   19,688 Kb/s
      Signed-off-by: NMarkus Stockhausen <stockhausen@collogia.de>
      Signed-off-by: NNeilBrown <neilb@suse.de>
      584acdd4
    • M
      md/raid6 algorithms: delta syndrome functions · fe5cbc6e
      Markus Stockhausen 提交于
      v3: s-o-b comment, explanation of performance and descision for
      the start/stop implementation
      
      Implementing rmw functionality for RAID6 requires optimized syndrome
      calculation. Up to now we can only generate a complete syndrome. The
      target P/Q pages are always overwritten. With this patch we provide
      a framework for inplace P/Q modification. In the first place simply
      fill those functions with NULL values.
      
      xor_syndrome() has two additional parameters: start & stop. These
      will indicate the first and last page that are changing during a
      rmw run. That makes it possible to avoid several unneccessary loops
      and speed up calculation. The caller needs to implement the following
      logic to make the functions work.
      
      1) xor_syndrome(disks, start, stop, ...): "Remove" all data of source
      blocks inside P/Q between (and including) start and end.
      
      2) modify any block with start <= block <= stop
      
      3) xor_syndrome(disks, start, stop, ...): "Reinsert" all data of
      source blocks into P/Q between (and including) start and end.
      
      Pages between start and stop that won't be changed should be filled
      with a pointer to the kernel zero page. The reasons for not taking NULL
      pages are:
      
      1) Algorithms cross the whole source data line by line. Thus avoid
      additional branches.
      
      2) Having a NULL page avoids calculating the XOR P parity but still
      need calulation steps for the Q parity. Depending on the algorithm
      unrolling that might be only a difference of 2 instructions per loop.
      
      The benchmark numbers of the gen_syndrome() functions are displayed in
      the kernel log. Do the same for the xor_syndrome() functions. This
      will help to analyze performance problems and give an rough estimate
      how well the algorithm works. The choice of the fastest algorithm will
      still depend on the gen_syndrome() performance.
      
      With the start/stop page implementation the speed can vary a lot in real
      life. E.g. a change of page 0 & page 15 on a stripe will be harder to
      compute than the case where page 0 & page 1 are XOR candidates. To be not
      to enthusiatic about the expected speeds we will run a worse case test
      that simulates a change on the upper half of the stripe. So we do:
      
      1) calculation of P/Q for the upper pages
      
      2) continuation of Q for the lower (empty) pages
      Signed-off-by: NMarkus Stockhausen <stockhausen@collogia.de>
      Signed-off-by: NNeilBrown <neilb@suse.de>
      fe5cbc6e
    • A
      uapi: Remove kernel internal declaration · bff17523
      Andreas Gruenbacher 提交于
      The enum nfs4_acl_whotype is only used in nfs4d's internal nfs4 acl
      representation. No longer expose it to user space.
      Signed-off-by: NAndreas Gruenbacher <agruenba@redhat.com>
      Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>
      bff17523
  15. 21 4月, 2015 3 次提交
  16. 20 4月, 2015 4 次提交