Commit graph

25449 commits

Author SHA1 Message Date
Al Viro 8bc5191b26 qnx4: don't leak ->BitMap on late failure exits
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-19 13:54:36 -05:00
Al Viro 4134bf81ff qnx4: reduce the insane nesting in qnx4_checkroot()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-19 13:40:57 -05:00
Al Viro 1aab323ea5 qnx4: di_fname is an array, for crying out loud...
(struct qnx4_inode_entry *)(bh->b_data + some_offset)->di_fname
is not going to be NULL, TYVM...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-19 13:19:42 -05:00
Miklos Szeredi 424a5334a5 vfs: remove printk from set_nlink()
Don't log a message for set_nlink(0).

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-17 16:39:47 -05:00
Kazuya Mio e1616300a2 wake up s_wait_unfrozen when ->freeze_fs fails
dd slept infinitely when fsfeeze failed because of EIO.
To fix this problem, if ->freeze_fs fails, freeze_super() wakes up
the tasks waiting for the filesystem to become unfrozen.

When s_frozen isn't SB_UNFROZEN in __generic_file_aio_write(),
the function sleeps until FITHAW ioctl wakes up s_wait_unfrozen.

However, if ->freeze_fs fails, s_frozen is set to SB_UNFROZEN and then
freeze_super() returns an error number. In this case, FITHAW ioctl returns
EINVAL because s_frozen is already SB_UNFROZEN. There is no way to wake up
s_wait_unfrozen, so __generic_file_aio_write() sleeps infinitely.

Signed-off-by: Kazuya Mio <k-mio@sx.jp.nec.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-17 16:38:47 -05:00
Linus Torvalds a12587b003 NFS client bugfixes and cleanups for Linux 3.3 (pull 2)
-----BEGIN PGP SIGNATURE-----
 Version: GnuPG v1.4.11 (GNU/Linux)
 
 iQIcBAABAgAGBQJPFJ45AAoJEGcL54qWCgDyy9QP/2LmBpYyu3L6vJKRDPxHO9/A
 geLuJsc+m+NU7V7k2H2PWj5TfLPyY33+FEdR0+iqmYVdCK+cb/fvXjeRmhwaFE78
 uoOs9x4LYtMUN+OCOdPJaNc8vosBxHfD9GE3Qb6KFKT4/2pjRu7kjbZvYEyufDhO
 FrPkSiJv5VUgV+xWsgp2C0FSbBFUQ4iGZ3nPeqJCLAT+1QEaJd3PIaJdUepGCi/X
 wakUGAWGKA/sWDcJgBbovVddB8j6FINmTrFme3ZSYqkOOF9mdmzxa/tvhFMjr/17
 sE2L3BHqQioRNXfjY4Ex3kGdVbuIVIIOSNAYeUysuunTSGsub0Ou+UJpj/CtNhur
 auZhjeZQrQUEd1j4Zb4knE3PyjF/GT1RV1CstmdDqty9+BPrzZdx8Rfj61IlLWEz
 b4DYT2HYxXifH5ZbDwA/uyApNKg95kjkp/OLGxwF640gIKXoeKo3xfJO+syQ5wKH
 AdBuTV0vPvkMwdY0H64IHghs47y7A3M/ZbK1jyAkaTzkq15GPqp49ojwFLc3UESb
 JiV/66hmmIJCAqEMu8OncHNtzsrZ2ZO5fqPSjhcrc4CEVCeqNy8WwP8she6BeR2U
 EwaWIqBs1zt5A6dZE8yxdu2Mvai3oRo/ioa6bPwxCAuy7o6/p2x/39TLe27fL18z
 1Qss51gQfFWe8lM8Rhj+
 =beF6
 -----END PGP SIGNATURE-----

Merge tag 'nfs-for-3.3-2' of git://git.linux-nfs.org/projects/trondmy/linux-nfs

NFS client bugfixes and cleanups for Linux 3.3 (pull 2)

* tag 'nfs-for-3.3-2' of git://git.linux-nfs.org/projects/trondmy/linux-nfs:
  pnfsblock: alloc short extent before submit bio
  pnfsblock: remove rpc_call_ops from struct parallel_io
  pnfsblock: move find lock page logic out of bl_write_pagelist
  pnfsblock: cleanup bl_mark_sectors_init
  pnfsblock: limit bio page count
  pnfsblock: don't spinlock when freeing block_dev
  pnfsblock: clean up _add_entry
  pnfsblock: set read/write tk_status to pnfs_error
  pnfsblock: acquire im_lock in _preload_range
  NFS4: fix compile warnings in nfs4proc.c
  nfs: check for integer overflow in decode_devicenotify_args()
  NFS: cleanup endian type in decode_ds_addr()
  NFS: add an endian notation
2012-01-16 15:08:13 -08:00
Linus Torvalds 122804ecb5 Merge branch 'v4l_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media
* 'v4l_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media: (655 commits)
  [media] revert patch: HDIC HD29L2 DMB-TH USB2.0 reference design driver
  mb86a20s: Add a few more register settings at the init seq
  mb86a20s: Group registers into the same line
  [media] [PATCH] don't reset the delivery system on DTV_CLEAR
  [media] [BUG] it913x-fe fix typo error making SNR levels unstable
  [media] cx23885: Query the CX25840 during enum_input for status
  [media] cx25840: Add support for g_input_status
  [media] rc-videomate-m1f.c Rename to match remote controler name
  [media] drivers: media: au0828: Fix dependency for VIDEO_AU0828
  [media] convert drivers/media/* to use module_platform_driver()
  [media] drivers: video: cx231xx: Fix dependency for VIDEO_CX231XX_DVB
  [media] Exynos4 JPEG codec v4l2 driver
  [media] doc: v4l: selection: choose pixels as units for selection rectangles
  [media] v4l: s5p-tv: mixer: fix setup of VP scaling
  [media] v4l: s5p-tv: mixer: add support for selection API
  [media] v4l: emulate old crop API using extended crop/compose API
  [media] doc: v4l: add documentation for selection API
  [media] doc: v4l: add binary images for selection API
  [media] v4l: add support for selection api
  [media] hd29l2: fix review findings
  ...
2012-01-15 12:49:56 -08:00
Linus Torvalds b3c9dd182e Merge branch 'for-3.3/core' of git://git.kernel.dk/linux-block
* 'for-3.3/core' of git://git.kernel.dk/linux-block: (37 commits)
  Revert "block: recursive merge requests"
  block: Stop using macro stubs for the bio data integrity calls
  blockdev: convert some macros to static inlines
  fs: remove unneeded plug in mpage_readpages()
  block: Add BLKROTATIONAL ioctl
  block: Introduce blk_set_stacking_limits function
  block: remove WARN_ON_ONCE() in exit_io_context()
  block: an exiting task should be allowed to create io_context
  block: ioc_cgroup_changed() needs to be exported
  block: recursive merge requests
  block, cfq: fix empty queue crash caused by request merge
  block, cfq: move icq creation and rq->elv.icq association to block core
  block, cfq: restructure io_cq creation path for io_context interface cleanup
  block, cfq: move io_cq exit/release to blk-ioc.c
  block, cfq: move icq cache management to block core
  block, cfq: move io_cq lookup to blk-ioc.c
  block, cfq: move cfqd->icq_list to request_queue and add request->elv.icq
  block, cfq: reorganize cfq_io_context into generic and cfq specific parts
  block: remove elevator_queue->ops
  block: reorder elevator switch sequence
  ...

Fix up conflicts in:
 - block/blk-cgroup.c
	Switch from can_attach_task to can_attach
 - block/cfq-iosched.c
	conflict with now removed cic index changes (we now use q->id instead)
2012-01-15 12:24:45 -08:00
Linus Torvalds a520458fcc Merge branch 'linux-next' of git://git.infradead.org/ubifs-2.6
* 'linux-next' of git://git.infradead.org/ubifs-2.6:
  UBI: use own macros for the layout volume
  UBI: fix nameless volumes handling
  UBIFS: fix non-debug configuration build
2012-01-15 11:25:41 -08:00
Dominique Martinet e234b5f207 UBIFS: fix non-debug configuration build
Fix a brown paperbag bug introduced by me in the previous commit. I was
in hurry and forgot about the non-debug case completely.

Artem: amend the commit message and tweak the patch to preserve alignment.
       This made the patch a bit less readable, though.

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@linux.intel.com>
2012-01-15 13:46:02 +02:00
Linus Torvalds c49c41a413 Merge branch 'for-linus' of git://selinuxproject.org/~jmorris/linux-security
* 'for-linus' of git://selinuxproject.org/~jmorris/linux-security:
  capabilities: remove __cap_full_set definition
  security: remove the security_netlink_recv hook as it is equivalent to capable()
  ptrace: do not audit capability check when outputing /proc/pid/stat
  capabilities: remove task_ns_* functions
  capabitlies: ns_capable can use the cap helpers rather than lsm call
  capabilities: style only - move capable below ns_capable
  capabilites: introduce new has_ns_capabilities_noaudit
  capabilities: call has_ns_capability from has_capability
  capabilities: remove all _real_ interfaces
  capabilities: introduce security_capable_noaudit
  capabilities: reverse arguments to security_capable
  capabilities: remove the task from capable LSM hook entirely
  selinux: sparse fix: fix several warnings in the security server cod
  selinux: sparse fix: fix warnings in netlink code
  selinux: sparse fix: eliminate warnings for selinuxfs
  selinux: sparse fix: declare selinux_disable() in security.h
  selinux: sparse fix: move selinux_complete_init
  selinux: sparse fix: make selinux_secmark_refcount static
  SELinux: Fix RCU deref check warning in sel_netport_insert()

Manually fix up a semantic mis-merge wrt security_netlink_recv():

 - the interface was removed in commit fd77846152 ("security: remove
   the security_netlink_recv hook as it is equivalent to capable()")

 - a new user of it appeared in commit a38f7907b9 ("crypto: Add
   userspace configuration API")

causing no automatic merge conflict, but Eric Paris pointed out the
issue.
2012-01-14 18:36:33 -08:00
Miklos Szeredi fed474857e fsnotify: don't BUG in fsnotify_destroy_mark()
Removing the parent of a watched file results in "kernel BUG at
fs/notify/mark.c:139".

To reproduce

  add "-w /tmp/audit/dir/watched_file" to audit.rules
  rm -rf /tmp/audit/dir

This is caused by fsnotify_destroy_mark() being called without an
extra reference taken by the caller.

Reported by Francesco Cosoleto here:

  https://bugzilla.novell.com/show_bug.cgi?id=689860

Fix by removing the BUG_ON and adding a comment about not accessing mark after
the iput.

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
CC: stable@vger.kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-01-14 18:01:42 -08:00
Linus Torvalds 0a80939b3e Autogenerated GPG tag for Rusty D1ADB8F1: 15EE 8D6C AB0E 7F0C F999 BFCB D920 0E6C D1AD B8F1
-----BEGIN PGP SIGNATURE-----
 Version: GnuPG v1.4.11 (GNU/Linux)
 
 iQIcBAABAgAGBQJPD2aFAAoJENkgDmzRrbjxNzsQAIeYbbrXYLjr6kQzUSngj/eC
 FzjaTEfYTQIeuQCFJHcHthyc5lXV4sQbo3jOezW+Bp5yuDJL2aWIHesSfWZe7imu
 zQdM4VshOYdAmUR9Q0AW5zhB8Smbs7/AyABiF2jm4p0ZPOuyMDSlei9sjvE9Vjvt
 B7g5ht7L6kz0JbDnwwy0u5gs+tEitwpXYId9Y4ysZIBzIbL0qkPX8veOddGTMy0N
 8xhWXaKtufpjvxFD2ORLDsw3AkoF1xXSNuFd/5nzCNpbeE7TW931jfkPoqJumuAO
 7GLxcU9kKYl+IICobC6wBtsj/RrB7w+cBXMvPGwdBliam1qaRhUcJZi5FLM/Ha5d
 2A9QDYNUpoXiO8JbPXrV9Z+Y0+Co8RilsQj7R/rjZh6AbbYCWt9nxzx2Svl/RfTr
 xfiimHuB2P3rHjOvpCXULwOOuE5c8MzPuWncpdjiD3uGXOY/aY+X1m+if/quJw9D
 grPlKL0+YiRakEYUeGG4M77KCqyKFZaF7L7UQPbqfZcj8V/9AW3/7U5I/B9RlAjs
 idsr4fcf5s0N+oKUyTCW1ncpUDQNiwbU2NyJQqeu1ZxaRGj72AgyvsaNeyIPDyK+
 f6x95Bi7i8KLjXc9Z1KvJwh2Nxt25gNUiTYVha/9H2NpJGd1cfI15kTOGXrgddVv
 1pvuGcJDZwYiwfiXr3FL
 =HHrh
 -----END PGP SIGNATURE-----

Merge tag 'for-linus' of git://github.com/rustyrussell/linux

Autogenerated GPG tag for Rusty D1ADB8F1: 15EE 8D6C AB0E 7F0C F999  BFCB D920 0E6C D1AD B8F1

* tag 'for-linus' of git://github.com/rustyrussell/linux:
  module_param: check that bool parameters really are bool.
  intelfbdrv.c: bailearly is an int module_param
  paride/pcd: fix bool verbose module parameter.
  module_param: make bool parameters really bool (drivers & misc)
  module_param: make bool parameters really bool (arch)
  module_param: make bool parameters really bool (core code)
  kernel/async: remove redundant declaration.
  printk: fix unnecessary module_param_name.
  lirc_parallel: fix module parameter description.
  module_param: avoid bool abuse, add bint for special cases.
  module_param: check type correctness for module_param_array
  modpost: use linker section to generate table.
  modpost: use a table rather than a giant if/else statement.
  modules: sysfs - export: taint, coresize, initsize
  kernel/params: replace DEBUGP with pr_debug
  module: replace DEBUGP with pr_debug
  module: struct module_ref should contains long fields
  module: Fix performance regression on modules with large symbol tables
  module: Add comments describing how the "strmap" logic works

Fix up conflicts in scripts/mod/file2alias.c due to the new linker-
generated table approach to adding __mod_*_device_table entries.  The
ARM sa11x0 mcp bus needed to be converted to that too.
2012-01-14 12:32:16 -08:00
Linus Torvalds 0b48d42235 Merge branch 'for-3.3' of git://linux-nfs.org/~bfields/linux
* 'for-3.3' of git://linux-nfs.org/~bfields/linux: (31 commits)
  nfsd4: nfsd4_create_clid_dir return value is unused
  NFSD: Change name of extended attribute containing junction
  svcrpc: don't revert to SVC_POOL_DEFAULT on nfsd shutdown
  svcrpc: fix double-free on shutdown of nfsd after changing pool mode
  nfsd4: be forgiving in the absence of the recovery directory
  nfsd4: fix spurious 4.1 post-reboot failures
  NFSD: forget_delegations should use list_for_each_entry_safe
  NFSD: Only reinitilize the recall_lru list under the recall lock
  nfsd4: initialize special stateid's at compile time
  NFSd: use network-namespace-aware cache registering routines
  SUNRPC: create svc_xprt in proper network namespace
  svcrpc: update outdated BKL comment
  nfsd41: allow non-reclaim open-by-fh's in 4.1
  svcrpc: avoid memory-corruption on pool shutdown
  svcrpc: destroy server sockets all at once
  svcrpc: make svc_delete_xprt static
  nfsd: Fix oops when parsing a 0 length export
  nfsd4: Use kmemdup rather than duplicating its implementation
  nfsd4: add a separate (lockowner, inode) lookup
  nfsd4: fix CONFIG_NFSD_FAULT_INJECTION compile error
  ...
2012-01-14 12:26:41 -08:00
Gleb Natapov 69e4747ee9 Unused iocbs in a batch should not be accounted as active.
Since commit 080d676de0 ("aio: allocate kiocbs in batches") iocbs are
allocated in a batch during processing of first iocbs.  All iocbs in a
batch are automatically added to ctx->active_reqs list and accounted in
ctx->reqs_active.

If one (not the last one) of iocbs submitted by an user fails, further
iocbs are not processed, but they are still present in ctx->active_reqs
and accounted in ctx->reqs_active.  This causes process to stuck in a D
state in wait_for_all_aios() on exit since ctx->reqs_active will never
go down to zero.  Furthermore since kiocb_batch_free() frees iocb
without removing it from active_reqs list the list become corrupted
which may cause oops.

Fix this by removing iocb from ctx->active_reqs and updating
ctx->reqs_active in kiocb_batch_free().

Signed-off-by: Gleb Natapov <gleb@redhat.com>
Reviewed-by: Jeff Moyer <jmoyer@redhat.com>
Cc: stable@kernel.org   # 3.2
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-01-13 20:39:44 -08:00
Linus Torvalds 96e80a7851 Merge git://git.kernel.org/pub/scm/linux/kernel/git/pkl/squashfs-next
* git://git.kernel.org/pub/scm/linux/kernel/git/pkl/squashfs-next:
  Squashfs: fix i_blocks calculation with extended regular files
  Squashfs: fix mount time sanity check for corrupted superblock
  Squashfs: optimise squashfs_cache_get entry search
  Squashfs: Update documentation to include xattrs
  Squashfs: add missing block release on error condition
2012-01-13 10:34:57 -08:00
Linus Torvalds 57e6a7dde8 Merge git://git.kernel.org/pub/scm/linux/kernel/git/steve/gfs2-3.0-nmw
* git://git.kernel.org/pub/scm/linux/kernel/git/steve/gfs2-3.0-nmw:
  GFS2: Fix nlink setting on inode creation
  GFS2: fail mount if journal recovery fails
  GFS2: let spectator mount do read only recovery
  GFS2: Fix a use-after-free that coverity spotted
  GFS2: dlm based recovery coordination
2012-01-13 10:33:39 -08:00
Linus Torvalds 94b1984ab9 Merge branch 'linux-next' of git://git.infradead.org/ubifs-2.6
* 'linux-next' of git://git.infradead.org/ubifs-2.6:
  UBIFS: fix key printing
  UBIFS: use snprintf instead of sprintf when printing keys
  UBIFS: fix debugging messages
  UBIFS: make debugging messages light again
  UBI: fix debugging messages
  UBI: make vid_hdr non-static
2012-01-13 10:31:33 -08:00
Linus Torvalds 1a52bb0b68 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client:
  ceph: ensure prealloc_blob is in place when removing xattr
  rbd: initialize snap_rwsem in rbd_add()
  ceph: enable/disable dentry complete flags via mount option
  vfs: export symbol d_find_any_alias()
  ceph: always initialize the dentry in open_root_dentry()
  libceph: remove useless return value for osd_client __send_request()
  ceph: avoid iput() while holding spinlock in ceph_dir_fsync
  ceph: avoid useless dget/dput in encode_fh
  ceph: dereference pointer after checking for NULL
  crush: fix force for non-root TAKE
  ceph: remove unnecessary d_fsdata conditional checks
  ceph: Use kmemdup rather than duplicating its implementation

Fix up conflicts in fs/ceph/super.c (d_alloc_root() failure handling vs
always initialize the dentry in open_root_dentry)
2012-01-13 10:29:21 -08:00
Ian Kent 8638094e95 autofs4 - fix deal with autofs4_write races
I don't know how I missed this obvious mistake when I
reviewed Als' patches, sorry.

[ Quoting Al:

	Grr...  Note to self: do git status *and* git stash show -p
	before git push.  Nothing like "WTF? I'd fixed that braino"
	feeling ;-/

  Al sent the same patch - it got broken in commit d668dc5663:
  "autofs4: deal with autofs4_write/autofs4_write races". ]

Reported-and-tested-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Ian Kent <raven@themaw.net>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-01-13 08:30:49 -08:00
Artem Bityutskiy 515315a123 UBIFS: fix key printing
Before commit 56e46742e8 we have had locking
around all printing macros and we could use static buffers for creating
key strings and printing them. However, now we do not have that locking and
we cannot use static buffers. This commit removes the old DBGKEY() macros
and introduces few new helper macros for printing debugging messages plus
a key at the end. Thankfully, all the messages are already structures in
a way that the key is printed in the end.

Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
2012-01-13 12:50:42 +02:00
Artem Bityutskiy beba006074 UBIFS: use snprintf instead of sprintf when printing keys
Switch to 'snprintf()' which is more secure and reliable. This is also a
preparation to the subsequent key printing fixes.

Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
2012-01-13 12:46:21 +02:00
Linus Torvalds 099469502f Merge branch 'akpm' (aka "Andrew's patch-bomb, take two")
Andrew explains:

 - various misc stuff

 - Most of the rest of MM: memcg, threaded hugepages, others.

 - cpumask

 - kexec

 - kdump

 - some direct-io performance tweaking

 - radix-tree optimisations

 - new selftests code

   A note on this: often people will develop a new userspace-visible
   feature and will develop userspace code to exercise/test that
   feature.  Then they merge the patch and the selftest code dies.
   Sometimes we paste it into the changelog.  Sometimes the code gets
   thrown into Documentation/(!).

   This saddens me.  So this patch creates a bare-bones framework which
   will henceforth allow me to ask people to include their test apps in
   the kernel tree so we can keep them alive.  Then when people enhance
   or fix the feature, I can ask them to update the test app too.

   The infrastruture is terribly trivial at present - let's see how it
   evolves.

 - checkpoint/restart feature work.

   A note on this: this is a project by various mad Russians to perform
   c/r mainly from userspace, with various oddball helper code added
   into the kernel where the need is demonstrated.

   So rather than some large central lump of code, what we have is
   little bits and pieces popping up in various places which either
   expose something new or which permit something which is normally
   kernel-private to be modified.

   The overall project is an ongoing thing.  I've judged that the size
   and scope of the thing means that we're more likely to be successful
   with it if we integrate the support into mainline piecemeal rather
   than allowing it all to develop out-of-tree.

   However I'm less confident than the developers that it will all
   eventually work! So what I'm asking them to do is to wrap each piece
   of new code inside CONFIG_CHECKPOINT_RESTORE.  So if it all
   eventually comes to tears and the project as a whole fails, it should
   be a simple matter to go through and delete all trace of it.

This lot pretty much wraps up the -rc1 merge for me.

* akpm: (96 commits)
  unlzo: fix input buffer free
  ramoops: update parameters only after successful init
  ramoops: fix use of rounddown_pow_of_two()
  c/r: prctl: add PR_SET_MM codes to set up mm_struct entries
  c/r: procfs: add start_data, end_data, start_brk members to /proc/$pid/stat v4
  c/r: introduce CHECKPOINT_RESTORE symbol
  selftests: new x86 breakpoints selftest
  selftests: new very basic kernel selftests directory
  radix_tree: take radix_tree_path off stack
  radix_tree: remove radix_tree_indirect_to_ptr()
  dio: optimize cache misses in the submission path
  vfs: cache request_queue in struct block_device
  fs/direct-io.c: calculate fs_count correctly in get_more_blocks()
  drivers/parport/parport_pc.c: fix warnings
  panic: don't print redundant backtraces on oops
  sysctl: add the kernel.ns_last_pid control
  kdump: add udev events for memory online/offline
  include/linux/crash_dump.h needs elf.h
  kdump: fix crash_kexec()/smp_send_stop() race in panic()
  kdump: crashk_res init check for /sys/kernel/kexec_crash_size
  ...
2012-01-12 20:42:54 -08:00
Cyrill Gorcunov b3f7f573a2 c/r: procfs: add start_data, end_data, start_brk members to /proc/$pid/stat v4
The mm->start_code/end_code, mm->start_data/end_data, mm->start_brk are
involved into calculation of program text/data segment sizes (which might
be seen in /proc/<pid>/statm) and into brk() call final address.

For restore we need to know all these values.  While
mm->start_code/end_code already present in /proc/$pid/stat, the rest
members are not, so this patch brings them in.

The restore procedure of these members is addressed in another patch using
prctl().

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Andrew Vagin <avagin@openvz.org>
Cc: Vasiliy Kulikov <segoon@openwall.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-01-12 20:13:13 -08:00
Andi Kleen 65dd2aa90a dio: optimize cache misses in the submission path
Some investigation of a transaction processing workload showed that a
major consumer of cycles in __blockdev_direct_IO is the cache miss while
accessing the block size.  This is because it has to walk the chain from
block_dev to gendisk to queue.

The block size is needed early on to check alignment and sizes.  It's only
done if the check for the inode block size fails.  But the costly block
device state is unconditionally fetched.

- Reorganize the code to only fetch block dev state when actually
  needed.

Then do a prefetch on the block dev early on in the direct IO path.  This
is worth it, because there is substantial code run before we actually
touch the block dev now.

- I also added some unlikelies to make it clear the compiler that block
  device fetch code is not normally executed.

This gave a small, but measurable improvement on a large database
benchmark (about 0.3%)

[akpm@linux-foundation.org: coding-style fixes]
[sfr@canb.auug.org.au: using prefetch requires including prefetch.h]
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Cc: Jeff Moyer <jmoyer@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-01-12 20:13:12 -08:00
Andi Kleen 87192a2a49 vfs: cache request_queue in struct block_device
This makes it possible to get from the inode to the request_queue with one
less cache miss.  Used in followon optimization.

The livetime of the pointer is the same as the gendisk.

This assumes that the queue will always stay the same in the gendisk while
it's visible to block_devices.  I think that's safe correct?

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Jeff Moyer <jmoyer@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-01-12 20:13:12 -08:00
Tao Ma ae55e1aaa7 fs/direct-io.c: calculate fs_count correctly in get_more_blocks()
In get_more_blocks(), we use dio_count to calcuate fs_count and do some
tricky things to increase fs_count if dio_count isn't aligned.  But
actually it still has some corner cases that can't be coverd.  See the
following example:

	dio_write foo -s 1024 -w 4096

(direct write 4096 bytes at offset 1024).  The same goes if the offset
isn't aligned to fs_blocksize.

In this case, the old calculation counts fs_count to be 1, but actually we
will write into 2 different blocks (if fs_blocksize=4096).  The old code
just works, since it will call get_block twice (and may have to allocate
and create extents twice for filesystems like ext4).  So we'd better call
get_block just once with the proper fs_count.

Signed-off-by: Tao Ma <boyu.mt@taobao.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-01-12 20:13:12 -08:00
Mel Gorman a6bc32b899 mm: compaction: introduce sync-light migration for use by compaction
This patch adds a lightweight sync migrate operation MIGRATE_SYNC_LIGHT
mode that avoids writing back pages to backing storage.  Async compaction
maps to MIGRATE_ASYNC while sync compaction maps to MIGRATE_SYNC_LIGHT.
For other migrate_pages users such as memory hotplug, MIGRATE_SYNC is
used.

This avoids sync compaction stalling for an excessive length of time,
particularly when copying files to a USB stick where there might be a
large number of dirty pages backed by a filesystem that does not support
->writepages.

[aarcange@redhat.com: This patch is heavily based on Andrea's work]
[akpm@linux-foundation.org: fix fs/nfs/write.c build]
[akpm@linux-foundation.org: fix fs/btrfs/disk-io.c build]
Signed-off-by: Mel Gorman <mgorman@suse.de>
Reviewed-by: Rik van Riel <riel@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Minchan Kim <minchan.kim@gmail.com>
Cc: Dave Jones <davej@redhat.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Andy Isaacson <adi@hexapodia.org>
Cc: Nai Xia <nai.xia@gmail.com>
Cc: Johannes Weiner <jweiner@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-01-12 20:13:09 -08:00
Mel Gorman b969c4ab9f mm: compaction: determine if dirty pages can be migrated without blocking within ->migratepage
Asynchronous compaction is used when allocating transparent hugepages to
avoid blocking for long periods of time.  Due to reports of stalling,
there was a debate on disabling synchronous compaction but this severely
impacted allocation success rates.  Part of the reason was that many dirty
pages are skipped in asynchronous compaction by the following check;

	if (PageDirty(page) && !sync &&
		mapping->a_ops->migratepage != migrate_page)
			rc = -EBUSY;

This skips over all mapping aops using buffer_migrate_page() even though
it is possible to migrate some of these pages without blocking.  This
patch updates the ->migratepage callback with a "sync" parameter.  It is
the responsibility of the callback to fail gracefully if migration would
block.

Signed-off-by: Mel Gorman <mgorman@suse.de>
Reviewed-by: Rik van Riel <riel@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Minchan Kim <minchan.kim@gmail.com>
Cc: Dave Jones <davej@redhat.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Andy Isaacson <adi@hexapodia.org>
Cc: Nai Xia <nai.xia@gmail.com>
Cc: Johannes Weiner <jweiner@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-01-12 20:13:09 -08:00
Jason Baron 28d82dc1c4 epoll: limit paths
The current epoll code can be tickled to run basically indefinitely in
both loop detection path check (on ep_insert()), and in the wakeup paths.
The programs that tickle this behavior set up deeply linked networks of
epoll file descriptors that cause the epoll algorithms to traverse them
indefinitely.  A couple of these sample programs have been previously
posted in this thread: https://lkml.org/lkml/2011/2/25/297.

To fix the loop detection path check algorithms, I simply keep track of
the epoll nodes that have been already visited.  Thus, the loop detection
becomes proportional to the number of epoll file descriptor and links.
This dramatically decreases the run-time of the loop check algorithm.  In
one diabolical case I tried it reduced the run-time from 15 mintues (all
in kernel time) to .3 seconds.

Fixing the wakeup paths could be done at wakeup time in a similar manner
by keeping track of nodes that have already been visited, but the
complexity is harder, since there can be multiple wakeups on different
cpus...Thus, I've opted to limit the number of possible wakeup paths when
the paths are created.

This is accomplished, by noting that the end file descriptor points that
are found during the loop detection pass (from the newly added link), are
actually the sources for wakeup events.  I keep a list of these file
descriptors and limit the number and length of these paths that emanate
from these 'source file descriptors'.  In the current implemetation I
allow 1000 paths of length 1, 500 of length 2, 100 of length 3, 50 of
length 4 and 10 of length 5.  Note that it is sufficient to check the
'source file descriptors' reachable from the newly added link, since no
other 'source file descriptors' will have newly added links.  This allows
us to check only the wakeup paths that may have gotten too long, and not
re-check all possible wakeup paths on the system.

In terms of the path limit selection, I think its first worth noting that
the most common case for epoll, is probably the model where you have 1
epoll file descriptor that is monitoring n number of 'source file
descriptors'.  In this case, each 'source file descriptor' has a 1 path of
length 1.  Thus, I believe that the limits I'm proposing are quite
reasonable and in fact may be too generous.  Thus, I'm hoping that the
proposed limits will not prevent any workloads that currently work to
fail.

In terms of locking, I have extended the use of the 'epmutex' to all
epoll_ctl add and remove operations.  Currently its only used in a subset
of the add paths.  I need to hold the epmutex, so that we can correctly
traverse a coherent graph, to check the number of paths.  I believe that
this additional locking is probably ok, since its in the setup/teardown
paths, and doesn't affect the running paths, but it certainly is going to
add some extra overhead.  Also, worth noting is that the epmuex was
recently added to the ep_ctl add operations in the initial path loop
detection code using the argument that it was not on a critical path.

Another thing to note here, is the length of epoll chains that is allowed.
Currently, eventpoll.c defines:

/* Maximum number of nesting allowed inside epoll sets */
#define EP_MAX_NESTS 4

This basically means that I am limited to a graph depth of 5 (EP_MAX_NESTS
+ 1).  However, this limit is currently only enforced during the loop
check detection code, and only when the epoll file descriptors are added
in a certain order.  Thus, this limit is currently easily bypassed.  The
newly added check for wakeup paths, stricly limits the wakeup paths to a
length of 5, regardless of the order in which ep's are linked together.
Thus, a side-effect of the new code is a more consistent enforcement of
the graph depth.

Thus far, I've tested this, using the sample programs previously
mentioned, which now either return quickly or return -EINVAL.  I've also
testing using the piptest.c epoll tester, which showed no difference in
performance.  I've also created a number of different epoll networks and
tested that they behave as expectded.

I believe this solves the original diabolical test cases, while still
preserving the sane epoll nesting.

Signed-off-by: Jason Baron <jbaron@redhat.com>
Cc: Nelson Elhage <nelhage@ksplice.com>
Cc: Davide Libenzi <davidel@xmailserver.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-01-12 20:13:04 -08:00
Sasha Levin 2ccd4f4d47 pipe: fail cleanly when root tries F_SETPIPE_SZ with big size
When a user with the CAP_SYS_RESOURCE cap tries to F_SETPIPE_SZ a pipe
with size bigger than kmalloc() can alloc it spits out an ugly warning:

  ------------[ cut here ]------------
  WARNING: at mm/page_alloc.c:2095 __alloc_pages_nodemask+0x5d3/0x7a0()
  Pid: 733, comm: a.out Not tainted 3.2.0-rc1+ #4
  Call Trace:
     warn_slowpath_common+0x75/0xb0
     warn_slowpath_null+0x15/0x20
     __alloc_pages_nodemask+0x5d3/0x7a0
     __get_free_pages+0x12/0x50
     __kmalloc+0x12b/0x150
     pipe_set_size+0x75/0x120
     pipe_fcntl+0xf8/0x140
     do_fcntl+0x2d4/0x410
     sys_fcntl+0x66/0xa0
     system_call_fastpath+0x16/0x1b
  ---[ end trace 432f702e6db7b5ee ]---

Instead, make kcalloc() handle the overflow case and fail quietly.

[akpm@linux-foundation.org: switch to sizeof(*bufs) for 80-column niceness]
Signed-off-by: Sasha Levin <levinsasha928@gmail.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Acked-by: Pekka Enberg <penberg@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-01-12 20:13:04 -08:00
Xiaotian Feng a2ef990ab5 proc: fix null pointer deref in proc_pid_permission()
get_proc_task() can fail to search the task and return NULL,
put_task_struct() will then bomb the kernel with following oops:

  BUG: unable to handle kernel NULL pointer dereference at 0000000000000010
  IP: [<ffffffff81217d34>] proc_pid_permission+0x64/0xe0
  PGD 112075067 PUD 112814067 PMD 0
  Oops: 0002 [#1] PREEMPT SMP

This is a regression introduced by commit 0499680a ("procfs: add hidepid=
and gid= mount options").  The kernel should return -ESRCH if
get_proc_task() failed.

Signed-off-by: Xiaotian Feng <dannyfeng@tencent.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Vasiliy Kulikov <segoon@openwall.com>
Cc: Stephen Wilson <wilsons@start.ca>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-01-12 20:13:02 -08:00
Rusty Russell 90ab5ee941 module_param: make bool parameters really bool (drivers & misc)
module_param(bool) used to counter-intuitively take an int.  In
fddd5201 (mid-2009) we allowed bool or int/unsigned int using a messy
trick.

It's time to remove the int/unsigned int option.  For this version
it'll simply give a warning, but it'll break next kernel version.

Acked-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2012-01-13 09:32:20 +10:30
Rusty Russell 69116f279a module_param: avoid bool abuse, add bint for special cases.
For historical reasons, we allow module_param(bool) to take an int (or
an unsigned int).  That's going away.

A few drivers really want an int: they set it to -1 and a parameter
will set it to 0 or 1.  This sucks: reading them from sysfs will give
'Y' for both -1 and 1, but if we change it to an int, then the users
might be broken (if they did "param" instead of "param=1").

Use a new 'bint' parser for them.

(ntfs has a different problem: it needs an int for debug_msgs because
it's also exposed via sysctl.)

Cc: Steve Glendinning <steve.glendinning@smsc.com>
Cc: Jean Delvare <khali@linux-fr.org>
Cc: Guenter Roeck <guenter.roeck@ericsson.com>
Cc: Hoang-Nam Nguyen <hnguyen@de.ibm.com>
Cc: Christoph Raisch <raisch@de.ibm.com>
Cc: Roland Dreier <roland@kernel.org>
Cc: Sean Hefty <sean.hefty@intel.com>
Cc: Hal Rosenstock <hal.rosenstock@gmail.com>
Cc: linux390@de.ibm.com
Cc: Anton Altaparmakov <anton@tuxera.com>
Cc: Jaroslav Kysela <perex@perex.cz>
Cc: Takashi Iwai <tiwai@suse.de>
Cc: lm-sensors@lm-sensors.org
Cc: linux-rdma@vger.kernel.org
Cc: linux-s390@vger.kernel.org
Cc: linux-ntfs-dev@lists.sourceforge.net
Cc: alsa-devel@alsa-project.org
Acked-by: Takashi Iwai <tiwai@suse.de> (For the sound part)
Acked-by: Guenter Roeck <guenter.roeck@ericsson.com> (For the hwmon driver)
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2012-01-13 09:32:17 +10:30
Peng Tao 7c5465d6cc pnfsblock: alloc short extent before submit bio
As discussed earlier, it is better for block client to allocate memory for
tracking extents state before submitting bio. So the patch does it by allocating
a short_extent for every INVALID extent touched by write pagelist and for
every zeroing page we created, saving them in layout header. Then in end_io we
can just use them to create commit list items and avoid memory allocation there.

Signed-off-by: Peng Tao <peng_tao@emc.com>
Signed-off-by: Benny Halevy <bhalevy@tonian.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2012-01-12 16:52:10 -05:00
Peng Tao c0411a94a8 pnfsblock: remove rpc_call_ops from struct parallel_io
block layout can just make use of generic read/write_done.

Signed-off-by: Peng Tao <peng_tao@emc.com>
Signed-off-by: Benny Halevy <bhalevy@tonian.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2012-01-12 16:52:10 -05:00
Peng Tao 72c5088799 pnfsblock: move find lock page logic out of bl_write_pagelist
Also avoid unnecessary lock_page if page is handled by others.

Signed-off-by: Peng Tao <peng_tao@emc.com>
Signed-off-by: Benny Halevy <bhalevy@tonian.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2012-01-12 16:52:10 -05:00
Peng Tao 60c52e3a72 pnfsblock: cleanup bl_mark_sectors_init
It does not need to manipulate on partial initialized blocks.
Writeback code takes care of it.

Signed-off-by: Peng Tao <peng_tao@emc.com>
Signed-off-by: Benny Halevy <bhalevy@tonian.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2012-01-12 16:52:09 -05:00
Peng Tao 74a6eeb44c pnfsblock: limit bio page count
One bio can have at most BIO_MAX_PAGES pages. We should limit it bec otherwise
bio_alloc will fail when there are many pages in one read/write_pagelist.

Cc: <stable@vger.kernel.org> #3.1+
Signed-off-by: Peng Tao <peng_tao@emc.com>
Signed-off-by: Benny Halevy <bhalevy@tonian.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2012-01-12 16:39:05 -05:00
Peng Tao 93a3844ee0 pnfsblock: don't spinlock when freeing block_dev
bl_free_block_dev() may sleep. We can not call it with spinlock held.
Besides, there is no need to take bm_lock as we are last user freeing bm_devlist.

Cc: <stable@vger.kernel.org> #3.1+
Signed-off-by: Peng Tao <peng_tao@emc.com>
Signed-off-by: Benny Halevy <bhalevy@tonian.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2012-01-12 16:39:04 -05:00
Peng Tao 57582b372f pnfsblock: clean up _add_entry
It is wrong to kmalloc in _add_entry() as it is inside
spinlock. memory should be already allocated _add_entry() is called.

Signed-off-by: Peng Tao <peng_tao@emc.com>
Signed-off-by: Benny Halevy <bhalevy@tonian.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2012-01-12 16:38:55 -05:00
Peng Tao 82b906d655 pnfsblock: set read/write tk_status to pnfs_error
To pass the IO status to upper layer.

Signed-off-by: Peng Tao <peng_tao@emc.com>
Signed-off-by: Benny Halevy <bhalevy@tonian.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2012-01-12 16:38:51 -05:00
Peng Tao 39e567ae36 pnfsblock: acquire im_lock in _preload_range
When calling _add_entry, we should take the im_lock to protect
agains other modifiers.

Cc: <stable@vger.kernel.org> #3.1+
Signed-off-by: Peng Tao <peng_tao@emc.com>
Signed-off-by: Benny Halevy <bhalevy@tonian.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2012-01-12 16:38:49 -05:00
Peng Tao de040beccd NFS4: fix compile warnings in nfs4proc.c
compile in nfs-for-3.3 branch shows following warnings. Fix it here.

fs/nfs/nfs4proc.c: In function ‘__nfs4_get_acl_uncached’:
fs/nfs/nfs4proc.c:3589: warning: format ‘%ld’ expects type ‘long int’, but argument 4 has type ‘size_t’
fs/nfs/nfs4proc.c:3589: warning: format ‘%ld’ expects type ‘long int’, but argument 6 has type ‘size_t’

Signed-off-by: Peng Tao <peng_tao@emc.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2012-01-12 16:31:51 -05:00
Dan Carpenter 363e0df057 nfs: check for integer overflow in decode_devicenotify_args()
On 32 bit, if n is too large then "n * sizeof(*args->devs)" could
overflow and args->devs would be smaller than expected.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2012-01-12 16:30:07 -05:00
Dan Carpenter 13fff2f35f NFS: cleanup endian type in decode_ds_addr()
port is supposed to be a __be16 here.  The existing code should work
fine, but this is a cleanup.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2012-01-12 16:30:03 -05:00
Dan Carpenter 0e0243dc35 NFS: add an endian notation
This function returns a big endian value.  The implementation in
fs/nfs/callback_proc.c is declared with "__be32" but the .h file uses
"unsigned" instead.  It makes sparse complain:

fs/nfs/callback_proc.c:232:8: error:
	symbol 'nfs4_callback_layoutrecall' redeclared with different
	type (originally declared at fs/nfs/callback.h:165) - different
	base types

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2012-01-12 16:29:51 -05:00
Linus Torvalds 6733e54b66 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse:
  FUSE: Notifying the kernel of deletion.
  fuse: support ioctl on directories
  fuse: Use kcalloc instead of kzalloc to allocate array
  fuse: llseek optimize SEEK_CUR and SEEK_SET
2012-01-12 12:39:21 -08:00
Alex Elder 83eb26af0d ceph: ensure prealloc_blob is in place when removing xattr
In __ceph_build_xattrs_blob(), if a ceph inode's extended attributes
are marked dirty, all attributes recorded in its rb_tree index are
formatted into a "blob" buffer.  The target buffer is recorded in
ceph_inode->i_xattrs.prealloc_blob, and it is expected to exist and
be of sufficient size to hold the attributes.

The extended attributes are marked dirty in two cases: when a new
attribute is added to the inode; or when one is removed.  In the
former case work is done to ensure the prealloc_blob buffer is
properly set up, but in the latter it is not.

Change the logic in ceph_removexattr() so it matches what is
done in ceph_setxattr().  Note that this is done in a way that
keeps the two blocks of code nearly identical, in anticipation
of a subsequent patch that encapsulates some of this logic into
one or more helper routines.

Signed-off-by: Alex Elder <elder@dreamhost.com>
Signed-off-by: Sage Weil <sage@newdream.net>
2012-01-12 11:00:51 -08:00
Sage Weil a40dc6cc2e ceph: enable/disable dentry complete flags via mount option
Enable/disable use of the dentry dir 'complete' flag via a mount option.
This lets the admin control whether ceph uses the dcache to satisfy
negative lookups or readdir when it has the entire directory contents in
its cache.

This is purely a performance optimization; correctness is guaranteed
whether it is enabled or not.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sage Weil <sage@newdream.net>
2012-01-12 11:00:40 -08:00