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  1. 15 5月, 2010 33 次提交
  3. 02 5月, 2010 2 次提交
    • D
      NFS: Fix RCU issues in the NFSv4 delegation code · 17d2c0a0
      由 David Howells 提交于 
      Fix a number of RCU issues in the NFSv4 delegation code.

 (1) delegation->cred doesn't need to be RCU protected as it's essentially an
     invariant refcounted structure.

     By the time we get to nfs_free_delegation(), the delegation is being
     released, so no one else should be attempting to use the saved
     credentials, and they can be cleared.

     However, since the list of delegations could still be under traversal at
     this point by such as nfs_client_return_marked_delegations(), the cred
     should be released in nfs_do_free_delegation() rather than in
     nfs_free_delegation().  Simply using rcu_assign_pointer() to clear it is
     insufficient as that doesn't stop the cred from being destroyed, and nor
     does calling put_rpccred() after call_rcu(), given that the latter is
     asynchronous.

 (2) nfs_detach_delegation_locked() and nfs_inode_set_delegation() should use
     rcu_derefence_protected() because they can only be called if
     nfs_client::cl_lock is held, and that guards against anyone changing
     nfsi->delegation under it.  Furthermore, the barrier imposed by
     rcu_dereference() is superfluous, given that the spin_lock() is also a
     barrier.

 (3) nfs_detach_delegation_locked() is now passed a pointer to the nfs_client
     struct so that it can issue lockdep advice based on clp->cl_lock for (2).

 (4) nfs_inode_return_delegation_noreclaim() and nfs_inode_return_delegation()
     should use rcu_access_pointer() outside the spinlocked region as they
     merely examine the pointer and don't follow it, thus rendering unnecessary
     the need to impose a partial ordering over the one item of interest.

     These result in an RCU warning like the following:

[ INFO: suspicious rcu_dereference_check() usage. ]
---------------------------------------------------
fs/nfs/delegation.c:332 invoked rcu_dereference_check() without protection!

other info that might help us debug this:

rcu_scheduler_active = 1, debug_locks = 0
2 locks held by mount.nfs4/2281:
 #0:  (&type->s_umount_key#34){+.+...}, at: [<ffffffff810b25b4>] deactivate_super+0x60/0x80
 #1:  (iprune_sem){+.+...}, at: [<ffffffff810c332a>] invalidate_inodes+0x39/0x13a

stack backtrace:
Pid: 2281, comm: mount.nfs4 Not tainted 2.6.34-rc1-cachefs #110
Call Trace:
 [<ffffffff8105149f>] lockdep_rcu_dereference+0xaa/0xb2
 [<ffffffffa00b4591>] nfs_inode_return_delegation_noreclaim+0x5b/0xa0 [nfs]
 [<ffffffffa0095d63>] nfs4_clear_inode+0x11/0x1e [nfs]
 [<ffffffff810c2d92>] clear_inode+0x9e/0xf8
 [<ffffffff810c3028>] dispose_list+0x67/0x10e
 [<ffffffff810c340d>] invalidate_inodes+0x11c/0x13a
 [<ffffffff810b1dc1>] generic_shutdown_super+0x42/0xf4
 [<ffffffff810b1ebe>] kill_anon_super+0x11/0x4f
 [<ffffffffa009893c>] nfs4_kill_super+0x3f/0x72 [nfs]
 [<ffffffff810b25bc>] deactivate_super+0x68/0x80
 [<ffffffff810c6744>] mntput_no_expire+0xbb/0xf8
 [<ffffffff810c681b>] release_mounts+0x9a/0xb0
 [<ffffffff810c689b>] put_mnt_ns+0x6a/0x79
 [<ffffffffa00983a1>] nfs_follow_remote_path+0x5a/0x146 [nfs]
 [<ffffffffa0098334>] ? nfs_do_root_mount+0x82/0x95 [nfs]
 [<ffffffffa00985a9>] nfs4_try_mount+0x75/0xaf [nfs]
 [<ffffffffa0098874>] nfs4_get_sb+0x291/0x31a [nfs]
 [<ffffffff810b2059>] vfs_kern_mount+0xb8/0x177
 [<ffffffff810b2176>] do_kern_mount+0x48/0xe8
 [<ffffffff810c810b>] do_mount+0x782/0x7f9
 [<ffffffff810c8205>] sys_mount+0x83/0xbe
 [<ffffffff81001eeb>] system_call_fastpath+0x16/0x1b

Also on:

fs/nfs/delegation.c:215 invoked rcu_dereference_check() without protection!
 [<ffffffff8105149f>] lockdep_rcu_dereference+0xaa/0xb2
 [<ffffffffa00b4223>] nfs_inode_set_delegation+0xfe/0x219 [nfs]
 [<ffffffffa00a9c6f>] nfs4_opendata_to_nfs4_state+0x2c2/0x30d [nfs]
 [<ffffffffa00aa15d>] nfs4_do_open+0x2a6/0x3a6 [nfs]
 ...

And:

fs/nfs/delegation.c:40 invoked rcu_dereference_check() without protection!
 [<ffffffff8105149f>] lockdep_rcu_dereference+0xaa/0xb2
 [<ffffffffa00b3bef>] nfs_free_delegation+0x3d/0x6e [nfs]
 [<ffffffffa00b3e71>] nfs_do_return_delegation+0x26/0x30 [nfs]
 [<ffffffffa00b406a>] __nfs_inode_return_delegation+0x1ef/0x1fe [nfs]
 [<ffffffffa00b448a>] nfs_client_return_marked_delegations+0xc9/0x124 [nfs]
 ...
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
      17d2c0a0
    • T
      NFSv4: Fix the locking in nfs_inode_reclaim_delegation() · 8f649c37
      由 Trond Myklebust 提交于 
      Ensure that we correctly rcu-dereference the delegation itself, and that we
protect against removal while we're changing the contents.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
      8f649c37
  5. 29 4月, 2010 3 次提交
    • A
      nfs d_revalidate() is too trigger-happy with d_drop() · d9e80b7d
      由 Al Viro 提交于 
      If dentry found stale happens to be a root of disconnected tree, we
can't d_drop() it; its d_hash is actually part of s_anon and d_drop()
would simply hide it from shrink_dcache_for_umount(), leading to
all sorts of fun, including busy inodes on umount and oopsen after
that.

Bug had been there since at least 2006 (commit c636eb already has it),
so it's definitely -stable fodder.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Cc: stable@kernel.org
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      d9e80b7d
    • X
      nfs: fix memory leak in nfs_get_sb with CONFIG_NFS_V4 · 9699eda6
      由 Xiaotian Feng 提交于 
      With CONFIG_NFS_V4 and data version 4, nfs_get_sb will allocate memory for
export_path in nfs4_validate_text_mount_data, so we need to free it then.
This is addressed in following kmemleak report:

unreferenced object 0xffff88016bf48a50 (size 16):
  comm "mount.nfs", pid 22567, jiffies 4651574704 (age 175471.200s)
  hex dump (first 16 bytes):
    2f 6f 70 74 2f 77 6f 72 6b 00 6b 6b 6b 6b 6b a5  /opt/work.kkkkk.
  backtrace:
    [<ffffffff814b34f9>] kmemleak_alloc+0x60/0xa7
    [<ffffffff81102c76>] kmemleak_alloc_recursive.clone.5+0x1b/0x1d
    [<ffffffff811046b3>] __kmalloc_track_caller+0x18f/0x1b7
    [<ffffffff810e1b08>] kstrndup+0x37/0x54
    [<ffffffffa0336971>] nfs_parse_devname+0x152/0x204 [nfs]
    [<ffffffffa0336af3>] nfs4_validate_text_mount_data+0xd0/0xdc [nfs]
    [<ffffffffa0338deb>] nfs_get_sb+0x325/0x736 [nfs]
    [<ffffffff81113671>] vfs_kern_mount+0xbd/0x17c
    [<ffffffff81113798>] do_kern_mount+0x4d/0xed
    [<ffffffff81129a87>] do_mount+0x787/0x7fe
    [<ffffffff81129b86>] sys_mount+0x88/0xc2
    [<ffffffff81009b42>] system_call_fastpath+0x16/0x1b
Signed-off-by: NXiaotian Feng <dfeng@redhat.com>
Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: Chuck Lever <chuck.lever@oracle.com>
Cc: Benny Halevy <bhalevy@panasas.com>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Andy Adamson <andros@netapp.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
      9699eda6
    • D
      nfs: fix some issues in nfs41_proc_reclaim_complete() · acf82b85
      由 Dan Carpenter 提交于 
      The original code passed an ERR_PTR() to rpc_put_task() and instead of
returning zero on success it returned -ENOMEM.
Signed-off-by: NDan Carpenter <error27@gmail.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
      acf82b85
  7. 28 4月, 2010 1 次提交
  9. 23 4月, 2010 1 次提交
    • T
      NFS: Fix an unstable write data integrity race · 71d0a611
      由 Trond Myklebust 提交于 
      Commit 2c61be0a (NFS: Ensure that the WRITE
and COMMIT RPC calls are always uninterruptible) exposed a race on file
close. In order to ensure correct close-to-open behaviour, we want to wait
for all outstanding background commit operations to complete.

This patch adds an inode flag that indicates if a commit operation is under
way, and provides a mechanism to allow ->write_inode() to wait for its
completion if this is a data integrity flush.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
      71d0a611