1. 24 6月, 2015 1 次提交
  2. 16 4月, 2015 1 次提交
  3. 12 4月, 2015 1 次提交
  4. 28 3月, 2015 1 次提交
  5. 04 3月, 2015 1 次提交
    • T
      NFS: Fix a regression in the read() syscall · 874f9463
      Trond Myklebust 提交于
      When invalidating the page cache for a regular file, we want to first
      sync all dirty data to disk and then call invalidate_inode_pages2().
      The latter relies on nfs_launder_page() and nfs_release_page() to deal
      respectively with dirty pages, and unstable written pages.
      
      When commit 95905446 ("NFS: avoid deadlocks with loop-back mounted
      NFS filesystems.") changed the behaviour of nfs_release_page(), then it
      made it possible for invalidate_inode_pages2() to fail with an EBUSY.
      Unfortunately, that error is then propagated back to read().
      
      Let's therefore work around the problem for now by protecting the call
      to sync the data and invalidate_inode_pages2() so that they are atomic
      w.r.t. the addition of new writes.
      Later on, we can revisit whether or not we still need nfs_launder_page()
      and nfs_release_page().
      Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>
      874f9463
  6. 02 3月, 2015 3 次提交
  7. 14 2月, 2015 1 次提交
  8. 25 11月, 2014 1 次提交
    • W
      NFS: fix subtle change in COMMIT behavior · cb1410c7
      Weston Andros Adamson 提交于
      Recent work in the pgio layer made it possible for there to be more than one
      request per page. This caused a subtle change in commit behavior, because
      write.c:nfs_commit_unstable_pages compares the number of *pages* waiting for
      writeback against the number of requests on a commit list to choose when to
      send a COMMIT in a non-blocking flush.
      
      This is probably hard to hit in normal operation - you have to be using
      rsize/wsize < PAGE_SIZE, or pnfs with lots of boundaries that are not page
      aligned to have a noticeable change in behavior.
      Signed-off-by: NWeston Andros Adamson <dros@primarydata.com>
      Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>
      cb1410c7
  9. 14 10月, 2014 1 次提交
  10. 13 9月, 2014 2 次提交
  11. 04 8月, 2014 2 次提交
    • N
      NFS: allow lockless access to access_cache · f682a398
      NeilBrown 提交于
      The access cache is used during RCU-walk path lookups, so it is best
      to avoid locking if possible as taking a lock kills concurrency.
      
      The rbtree is not rcu-safe and cannot easily be made so.
      Instead we simply check the last (i.e. most recent) entry on the LRU
      list.  If this doesn't match, then we return -ECHILD and retry in
      lock/refcount mode.
      
      This requires freeing the nfs_access_entry struct with rcu, and
      requires using rcu access primatives when adding entries to the lru, and
      when examining the last entry.
      
      Calling put_rpccred before kfree_rcu looks a bit odd, but as
      put_rpccred already provides rcu protection, we know that the cred will
      not actually be freed until the next grace period, so any concurrent
      access will be safe.
      
      This patch provides about 5% performance improvement on a stat-heavy
      synthetic work load with 4 threads on a 2-core CPU.
      Signed-off-by: NNeilBrown <neilb@suse.de>
      Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>
      f682a398
    • N
      NFS: teach nfs_neg_need_reval to understand LOOKUP_RCU · 912a108d
      NeilBrown 提交于
      This requires nfs_check_verifier to take an rcu_walk flag, and requires
      an rcu version of nfs_revalidate_inode which returns -ECHILD rather
      than making an RPC call.
      
      With this, nfs_lookup_revalidate can call nfs_neg_need_reval in
      RCU-walk mode.
      
      We can also move the LOOKUP_RCU check past the nfs_check_verifier()
      call in nfs_lookup_revalidate.
      
      If RCU_WALK prevents nfs_check_verifier or nfs_neg_need_reval from
      doing a full check, they return a status indicating that a revalidation
      is required.  As this revalidation will not be possible in RCU_WALK
      mode, -ECHILD will ultimately be returned, which is the desired result.
      Signed-off-by: NNeilBrown <neilb@suse.de>
      Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>
      912a108d
  12. 29 5月, 2014 2 次提交
  13. 07 5月, 2014 2 次提交
  14. 18 3月, 2014 1 次提交
  15. 12 2月, 2014 1 次提交
  16. 28 1月, 2014 1 次提交
    • J
      NFS: fix the handling of NFS_INO_INVALID_DATA flag in nfs_revalidate_mapping · d529ef83
      Jeff Layton 提交于
      There is a possible race in how the nfs_invalidate_mapping function is
      handled.  Currently, we go and invalidate the pages in the file and then
      clear NFS_INO_INVALID_DATA.
      
      The problem is that it's possible for a stale page to creep into the
      mapping after the page was invalidated (i.e., via readahead). If another
      writer comes along and sets the flag after that happens but before
      invalidate_inode_pages2 returns then we could clear the flag
      without the cache having been properly invalidated.
      
      So, we must clear the flag first and then invalidate the pages. Doing
      this however, opens another race:
      
      It's possible to have two concurrent read() calls that end up in
      nfs_revalidate_mapping at the same time. The first one clears the
      NFS_INO_INVALID_DATA flag and then goes to call nfs_invalidate_mapping.
      
      Just before calling that though, the other task races in, checks the
      flag and finds it cleared. At that point, it trusts that the mapping is
      good and gets the lock on the page, allowing the read() to be satisfied
      from the cache even though the data is no longer valid.
      
      These effects are easily manifested by running diotest3 from the LTP
      test suite on NFS. That program does a series of DIO writes and buffered
      reads. The operations are serialized and page-aligned but the existing
      code fails the test since it occasionally allows a read to come out of
      the cache incorrectly. While mixing direct and buffered I/O isn't
      recommended, I believe it's possible to hit this in other ways that just
      use buffered I/O, though that situation is much harder to reproduce.
      
      The problem is that the checking/clearing of that flag and the
      invalidation of the mapping really need to be atomic. Fix this by
      serializing concurrent invalidations with a bitlock.
      
      At the same time, we also need to allow other places that check
      NFS_INO_INVALID_DATA to check whether we might be in the middle of
      invalidating the file, so fix up a couple of places that do that
      to look for the new NFS_INO_INVALIDATING flag.
      
      Doing this requires us to be careful not to set the bitlock
      unnecessarily, so this code only does that if it believes it will
      be doing an invalidation.
      Signed-off-by: NJeff Layton <jlayton@redhat.com>
      Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>
      d529ef83
  17. 26 1月, 2014 1 次提交
  18. 20 11月, 2013 1 次提交
  19. 28 9月, 2013 1 次提交
    • D
      NFS: Use i_writecount to control whether to get an fscache cookie in nfs_open() · f1fe29b4
      David Howells 提交于
      Use i_writecount to control whether to get an fscache cookie in nfs_open() as
      NFS does not do write caching yet.  I *think* this is the cause of a problem
      encountered by Mark Moseley whereby __fscache_uncache_page() gets a NULL
      pointer dereference because cookie->def is NULL:
      
      BUG: unable to handle kernel NULL pointer dereference at 0000000000000010
      IP: [<ffffffff812a1903>] __fscache_uncache_page+0x23/0x160
      PGD 0
      Thread overran stack, or stack corrupted
      Oops: 0000 [#1] SMP
      Modules linked in: ...
      CPU: 7 PID: 18993 Comm: php Not tainted 3.11.1 #1
      Hardware name: Dell Inc. PowerEdge R420/072XWF, BIOS 1.3.5 08/21/2012
      task: ffff8804203460c0 ti: ffff880420346640
      RIP: 0010:[<ffffffff812a1903>] __fscache_uncache_page+0x23/0x160
      RSP: 0018:ffff8801053af878 EFLAGS: 00210286
      RAX: 0000000000000000 RBX: ffff8800be2f8780 RCX: ffff88022ffae5e8
      RDX: 0000000000004c66 RSI: ffffea00055ff440 RDI: ffff8800be2f8780
      RBP: ffff8801053af898 R08: 0000000000000001 R09: 0000000000000003
      R10: 0000000000000000 R11: 0000000000000000 R12: ffffea00055ff440
      R13: 0000000000001000 R14: ffff8800c50be538 R15: 0000000000000000
      FS: 0000000000000000(0000) GS:ffff88042fc60000(0063) knlGS:00000000e439c700
      CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033
      CR2: 0000000000000010 CR3: 0000000001d8f000 CR4: 00000000000607f0
      Stack:
      ...
      Call Trace:
      [<ffffffff81365a72>] __nfs_fscache_invalidate_page+0x42/0x70
      [<ffffffff813553d5>] nfs_invalidate_page+0x75/0x90
      [<ffffffff811b8f5e>] truncate_inode_page+0x8e/0x90
      [<ffffffff811b90ad>] truncate_inode_pages_range.part.12+0x14d/0x620
      [<ffffffff81d6387d>] ? __mutex_lock_slowpath+0x1fd/0x2e0
      [<ffffffff811b95d3>] truncate_inode_pages_range+0x53/0x70
      [<ffffffff811b969d>] truncate_inode_pages+0x2d/0x40
      [<ffffffff811b96ff>] truncate_pagecache+0x4f/0x70
      [<ffffffff81356840>] nfs_setattr_update_inode+0xa0/0x120
      [<ffffffff81368de4>] nfs3_proc_setattr+0xc4/0xe0
      [<ffffffff81357f78>] nfs_setattr+0xc8/0x150
      [<ffffffff8122d95b>] notify_change+0x1cb/0x390
      [<ffffffff8120a55b>] do_truncate+0x7b/0xc0
      [<ffffffff8121f96c>] do_last+0xa4c/0xfd0
      [<ffffffff8121ffbc>] path_openat+0xcc/0x670
      [<ffffffff81220a0e>] do_filp_open+0x4e/0xb0
      [<ffffffff8120ba1f>] do_sys_open+0x13f/0x2b0
      [<ffffffff8126aaf6>] compat_SyS_open+0x36/0x50
      [<ffffffff81d7204c>] sysenter_dispatch+0x7/0x24
      
      The code at the instruction pointer was disassembled:
      
      > (gdb) disas __fscache_uncache_page
      > Dump of assembler code for function __fscache_uncache_page:
      > ...
      > 0xffffffff812a18ff <+31>: mov 0x48(%rbx),%rax
      > 0xffffffff812a1903 <+35>: cmpb $0x0,0x10(%rax)
      > 0xffffffff812a1907 <+39>: je 0xffffffff812a19cd <__fscache_uncache_page+237>
      
      These instructions make up:
      
      	ASSERTCMP(cookie->def->type, !=, FSCACHE_COOKIE_TYPE_INDEX);
      
      That cmpb is the faulting instruction (%rax is 0).  So cookie->def is NULL -
      which presumably means that the cookie has already been at least partway
      through __fscache_relinquish_cookie().
      
      What I think may be happening is something like a three-way race on the same
      file:
      
      	PROCESS 1	PROCESS 2	PROCESS 3
      	===============	===============	===============
      	open(O_TRUNC|O_WRONLY)
      			open(O_RDONLY)
      					open(O_WRONLY)
      	-->nfs_open()
      	-->nfs_fscache_set_inode_cookie()
      	nfs_fscache_inode_lock()
      	nfs_fscache_disable_inode_cookie()
      	__fscache_relinquish_cookie()
      	nfs_inode->fscache = NULL
      	<--nfs_fscache_set_inode_cookie()
      
      			-->nfs_open()
      			-->nfs_fscache_set_inode_cookie()
      			nfs_fscache_inode_lock()
      			nfs_fscache_enable_inode_cookie()
      			__fscache_acquire_cookie()
      			nfs_inode->fscache = cookie
      			<--nfs_fscache_set_inode_cookie()
      	<--nfs_open()
      	-->nfs_setattr()
      	...
      	...
      	-->nfs_invalidate_page()
      	-->__nfs_fscache_invalidate_page()
      	cookie = nfsi->fscache
      					-->nfs_open()
      					-->nfs_fscache_set_inode_cookie()
      					nfs_fscache_inode_lock()
      					nfs_fscache_disable_inode_cookie()
      					-->__fscache_relinquish_cookie()
      	-->__fscache_uncache_page(cookie)
      	<crash>
      					<--__fscache_relinquish_cookie()
      					nfs_inode->fscache = NULL
      					<--nfs_fscache_set_inode_cookie()
      
      What is needed is something to prevent process #2 from reacquiring the cookie
      - and I think checking i_writecount should do the trick.
      
      It's also possible to have a two-way race on this if the file is opened
      O_TRUNC|O_RDONLY instead.
      Reported-by: NMark Moseley <moseleymark@gmail.com>
      Signed-off-by: NDavid Howells <dhowells@redhat.com>
      f1fe29b4
  20. 04 9月, 2013 1 次提交
  21. 10 7月, 2013 1 次提交
  22. 09 6月, 2013 3 次提交
  23. 07 6月, 2013 1 次提交
  24. 09 4月, 2013 1 次提交
  25. 26 3月, 2013 1 次提交
  26. 13 10月, 2012 1 次提交
  27. 02 10月, 2012 1 次提交
    • W
      NFSv4: Add ACCESS operation to OPEN compound · 6168f62c
      Weston Andros Adamson 提交于
      The OPEN operation has no way to differentiate an open for read and an
      open for execution - both look like read to the server. This allowed
      users to read files that didn't have READ access but did have EXEC access,
      which is obviously wrong.
      
      This patch adds an ACCESS call to the OPEN compound to handle the
      difference between OPENs for reading and execution.  Since we're going
      through the trouble of calling ACCESS, we check all possible access bits
      and cache the results hopefully avoiding an ACCESS call in the future.
      Signed-off-by: NWeston Andros Adamson <dros@netapp.com>
      Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
      6168f62c
  28. 29 9月, 2012 2 次提交
  29. 05 9月, 2012 1 次提交
  30. 01 8月, 2012 1 次提交
    • M
      nfs: enable swap on NFS · a564b8f0
      Mel Gorman 提交于
      Implement the new swapfile a_ops for NFS and hook up ->direct_IO.  This
      will set the NFS socket to SOCK_MEMALLOC and run socket reconnect under
      PF_MEMALLOC as well as reset SOCK_MEMALLOC before engaging the protocol
      ->connect() method.
      
      PF_MEMALLOC should allow the allocation of struct socket and related
      objects and the early (re)setting of SOCK_MEMALLOC should allow us to
      receive the packets required for the TCP connection buildup.
      
      [jlayton@redhat.com: Restore PF_MEMALLOC task flags in all cases]
      [dfeng@redhat.com: Fix handling of multiple swap files]
      [a.p.zijlstra@chello.nl: Original patch]
      Signed-off-by: NMel Gorman <mgorman@suse.de>
      Acked-by: NRik van Riel <riel@redhat.com>
      Cc: Christoph Hellwig <hch@infradead.org>
      Cc: David S. Miller <davem@davemloft.net>
      Cc: Eric B Munson <emunson@mgebm.net>
      Cc: Eric Paris <eparis@redhat.com>
      Cc: James Morris <jmorris@namei.org>
      Cc: Mel Gorman <mgorman@suse.de>
      Cc: Mike Christie <michaelc@cs.wisc.edu>
      Cc: Neil Brown <neilb@suse.de>
      Cc: Sebastian Andrzej Siewior <sebastian@breakpoint.cc>
      Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
      Cc: Xiaotian Feng <dfeng@redhat.com>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      a564b8f0
  31. 31 7月, 2012 1 次提交