CIFS request buffers, stored in the cifs_request slab cache, need to be
copied to/from userspace.

cache object allocation:
    fs/cifs/cifsfs.c:
        cifs_init_request_bufs():
            ...
            cifs_req_poolp = mempool_create_slab_pool(cifs_min_rcv,
                                                      cifs_req_cachep);

    fs/cifs/misc.c:
        cifs_buf_get():
            ...
            ret_buf = mempool_alloc(cifs_req_poolp, GFP_NOFS);
            ...
            return ret_buf;

In support of usercopy hardening, this patch defines a region in the
cifs_request slab cache in which userspace copy operations are allowed.

This region is known as the slab cache's usercopy region. Slab caches
can now check that each dynamically sized copy operation involving
cache-managed memory falls entirely within the slab's usercopy region.

This patch is verbatim from Brad Spengler/PaX Team's PAX_USERCOPY
whitelisting code in the last public patch of grsecurity/PaX based on my
understanding of the code. Changes or omissions from the original code are
mine and don't reflect the original grsecurity/PaX code.
Signed-off-by: NDavid Windsor <dave@nullcore.net>
[kees: adjust commit log, provide usage trace]
Cc: Steve French <sfrench@samba.org>
Cc: linux-cifs@vger.kernel.org
Signed-off-by: NKees Cook <keescook@chromium.org>

This is a pure automated search-and-replace of the internal kernel
superblock flags.

The s_flags are now called SB_*, with the names and the values for the
moment mirroring the MS_* flags that they're equivalent to.

Note how the MS_xyz flags are the ones passed to the mount system call,
while the SB_xyz flags are what we then use in sb->s_flags.

The script to do this was:

    # places to look in; re security/*: it generally should *not* be
    # touched (that stuff parses mount(2) arguments directly), but
    # there are two places where we really deal with superblock flags.
    FILES="drivers/mtd drivers/staging/lustre fs ipc mm \
            include/linux/fs.h include/uapi/linux/bfs_fs.h \
            security/apparmor/apparmorfs.c security/apparmor/include/lib.h"
    # the list of MS_... constants
    SYMS="RDONLY NOSUID NODEV NOEXEC SYNCHRONOUS REMOUNT MANDLOCK \
          DIRSYNC NOATIME NODIRATIME BIND MOVE REC VERBOSE SILENT \
          POSIXACL UNBINDABLE PRIVATE SLAVE SHARED RELATIME KERNMOUNT \
          I_VERSION STRICTATIME LAZYTIME SUBMOUNT NOREMOTELOCK NOSEC BORN \
          ACTIVE NOUSER"

    SED_PROG=
    for i in $SYMS; do SED_PROG="$SED_PROG -e s/MS_$i/SB_$i/g"; done

    # we want files that contain at least one of MS_...,
    # with fs/namespace.c and fs/pnode.c excluded.
    L=$(for i in $SYMS; do git grep -w -l MS_$i $FILES; done| sort|uniq|grep -v '^fs/namespace.c'|grep -v '^fs/pnode.c')

    for f in $L; do sed -i $f $SED_PROG; done
Requested-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

memory leak was found by kmemleak. exit_cifs_spnego
should be called before cifs module removed, or
cifs root_cred will not be released.

kmemleak report:
unreferenced object 0xffff880070a3ce40 (size 192):
  backtrace:
     kmemleak_alloc+0x4a/0xa0
     kmem_cache_alloc+0xc7/0x1d0
     prepare_kernel_cred+0x20/0x120
     init_cifs_spnego+0x2d/0x170 [cifs]
     0xffffffffc07801f3
     do_one_initcall+0x51/0x1b0
     do_init_module+0x60/0x1fd
     load_module+0x161e/0x1b60
     SYSC_finit_module+0xa9/0x100
     SyS_finit_module+0xe/0x10
Signed-off-by: NShu Wang <shuwang@redhat.com>
Signed-off-by: NSteve French <smfrench@gmail.com>
Reviewed-by: NRonnie Sahlberg <lsahlber@redhat.com>
CC: Stable <stable@vger.kernel.org>

Signed-off-by: NRonnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: NSteve French <smfrench@gmail.com>

Remove the CONFIG_CIFS_SMB2 ifdef and Kconfig option since they
must always be on now.

For various security reasons, SMB3 and later are STRONGLY preferred
over CIFS and older dialects, and SMB3 (and later) will now be
the default dialects so we do not want to allow them to be
ifdeffed out.

In the longer term, we may be able to make older CIFS support
disableable in Kconfig with a new set of #ifdef, but we always
want SMB3 and later support enabled.
Signed-off-by: NSteven French <smfrench@gmail.com>
Reviewed-by: NPavel Shilovsky <pshilov@microsoft.com>

Using get_random_u32 here is faster, more fitting of the use case, and
just as cryptographically secure. It also has the benefit of providing
better randomness at early boot, which is sometimes when this is used.
Signed-off-by: NJason A. Donenfeld <Jason@zx2c4.com>
Cc: Steve French <sfrench@samba.org>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>

When the final cifsFileInfo_put() is called from cifsiod and an oplock
break work is queued, lockdep complains loudly:

 =============================================
 [ INFO: possible recursive locking detected ]
 4.11.0+ #21 Not tainted
 ---------------------------------------------
 kworker/0:2/78 is trying to acquire lock:
  ("cifsiod"){++++.+}, at: flush_work+0x215/0x350

 but task is already holding lock:
  ("cifsiod"){++++.+}, at: process_one_work+0x255/0x8e0

 other info that might help us debug this:
  Possible unsafe locking scenario:

        CPU0
        ----
   lock("cifsiod");
   lock("cifsiod");

  *** DEADLOCK ***

  May be due to missing lock nesting notation

 2 locks held by kworker/0:2/78:
  #0:  ("cifsiod"){++++.+}, at: process_one_work+0x255/0x8e0
  #1:  ((&wdata->work)){+.+...}, at: process_one_work+0x255/0x8e0

 stack backtrace:
 CPU: 0 PID: 78 Comm: kworker/0:2 Not tainted 4.11.0+ #21
 Workqueue: cifsiod cifs_writev_complete
 Call Trace:
  dump_stack+0x85/0xc2
  __lock_acquire+0x17dd/0x2260
  ? match_held_lock+0x20/0x2b0
  ? trace_hardirqs_off_caller+0x86/0x130
  ? mark_lock+0xa6/0x920
  lock_acquire+0xcc/0x260
  ? lock_acquire+0xcc/0x260
  ? flush_work+0x215/0x350
  flush_work+0x236/0x350
  ? flush_work+0x215/0x350
  ? destroy_worker+0x170/0x170
  __cancel_work_timer+0x17d/0x210
  ? ___preempt_schedule+0x16/0x18
  cancel_work_sync+0x10/0x20
  cifsFileInfo_put+0x338/0x7f0
  cifs_writedata_release+0x2a/0x40
  ? cifs_writedata_release+0x2a/0x40
  cifs_writev_complete+0x29d/0x850
  ? preempt_count_sub+0x18/0xd0
  process_one_work+0x304/0x8e0
  worker_thread+0x9b/0x6a0
  kthread+0x1b2/0x200
  ? process_one_work+0x8e0/0x8e0
  ? kthread_create_on_node+0x40/0x40
  ret_from_fork+0x31/0x40

This is a real warning.  Since the oplock is queued on the same
workqueue this can deadlock if there is only one worker thread active
for the workqueue (which will be the case during memory pressure when
the rescuer thread is handling it).

Furthermore, there is at least one other kind of hang possible due to
the oplock break handling if there is only worker.  (This can be
reproduced without introducing memory pressure by having passing 1 for
the max_active parameter of cifsiod.) cifs_oplock_break() can wait
indefintely in the filemap_fdatawait() while the cifs_writev_complete()
work is blocked:

 sysrq: SysRq : Show Blocked State
   task                        PC stack   pid father
 kworker/0:1     D    0    16      2 0x00000000
 Workqueue: cifsiod cifs_oplock_break
 Call Trace:
  __schedule+0x562/0xf40
  ? mark_held_locks+0x4a/0xb0
  schedule+0x57/0xe0
  io_schedule+0x21/0x50
  wait_on_page_bit+0x143/0x190
  ? add_to_page_cache_lru+0x150/0x150
  __filemap_fdatawait_range+0x134/0x190
  ? do_writepages+0x51/0x70
  filemap_fdatawait_range+0x14/0x30
  filemap_fdatawait+0x3b/0x40
  cifs_oplock_break+0x651/0x710
  ? preempt_count_sub+0x18/0xd0
  process_one_work+0x304/0x8e0
  worker_thread+0x9b/0x6a0
  kthread+0x1b2/0x200
  ? process_one_work+0x8e0/0x8e0
  ? kthread_create_on_node+0x40/0x40
  ret_from_fork+0x31/0x40
 dd              D    0   683    171 0x00000000
 Call Trace:
  __schedule+0x562/0xf40
  ? mark_held_locks+0x29/0xb0
  schedule+0x57/0xe0
  io_schedule+0x21/0x50
  wait_on_page_bit+0x143/0x190
  ? add_to_page_cache_lru+0x150/0x150
  __filemap_fdatawait_range+0x134/0x190
  ? do_writepages+0x51/0x70
  filemap_fdatawait_range+0x14/0x30
  filemap_fdatawait+0x3b/0x40
  filemap_write_and_wait+0x4e/0x70
  cifs_flush+0x6a/0xb0
  filp_close+0x52/0xa0
  __close_fd+0xdc/0x150
  SyS_close+0x33/0x60
  entry_SYSCALL_64_fastpath+0x1f/0xbe

 Showing all locks held in the system:
 2 locks held by kworker/0:1/16:
  #0:  ("cifsiod"){.+.+.+}, at: process_one_work+0x255/0x8e0
  #1:  ((&cfile->oplock_break)){+.+.+.}, at: process_one_work+0x255/0x8e0

 Showing busy workqueues and worker pools:
 workqueue cifsiod: flags=0xc
   pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/1
     in-flight: 16:cifs_oplock_break
     delayed: cifs_writev_complete, cifs_echo_request
 pool 0: cpus=0 node=0 flags=0x0 nice=0 hung=0s workers=3 idle: 750 3

Fix these problems by creating a a new workqueue (with a rescuer) for
the oplock break work.
Signed-off-by: NRabin Vincent <rabinv@axis.com>
Signed-off-by: NSteve French <smfrench@gmail.com>
CC: Stable <stable@vger.kernel.org>

Allocate struct backing_dev_info separately instead of embedding it
inside superblock. This unifies handling of bdi among users.

CC: Steve French <sfrench@samba.org>
CC: linux-cifs@vger.kernel.org
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJan Kara <jack@suse.cz>
Signed-off-by: NJens Axboe <axboe@fb.com>

The earlier changes to copy range for cifs unintentionally disabled the more
common form of server side copy.

The patch introduces the file_operations helper cifs_copy_file_range()
which is used by the syscall copy_file_range. The new file operations
helper allows us to perform server side copies for SMB2.0 and 2.1
servers as well as SMB 3.0+ servers which do not support the ioctl
FSCTL_DUPLICATE_EXTENTS_TO_FILE.

The new helper uses the ioctl FSCTL_SRV_COPYCHUNK_WRITE to perform
server side copies. The helper is called by vfs_copy_file_range() only
once an attempt to clone the file using the ioctl
FSCTL_DUPLICATE_EXTENTS_TO_FILE has failed.
Signed-off-by: NSachin Prabhu <sprabhu@redhat.com>
Reviewed-by: NPavel Shilovsky <pshilov@microsoft.com>
CC: Stable  <stable@vger.kernel.org>
Signed-off-by: NSteve French <smfrench@gmail.com>

There is an include loop between netdevice.h, dsa.h, devlink.h because
of NETDEV_ALIGN, making it impossible to use devlink structures in
dsa.h.

Break this loop by taking dsa.h out of netdevice.h, add a forward
declaration of dsa_switch_tree and netdev_set_default_ethtool_ops()
function, which is what netdevice.h requires.

No longer having dsa.h in netdevice.h means the includes in dsa.h no
longer get included. This breaks a few other files which depend on
these includes. Add these directly in the affected file.
Signed-off-by: NAndrew Lunn <andrew@lunn.ch>
Reviewed-by: NFlorian Fainelli <f.fainelli@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This change allows to encrypt packets if it is required by a server
for SMB sessions or tree connections.
Signed-off-by: NPavel Shilovsky <pshilov@microsoft.com>

List soft dependencies of cifs so that mkinitrd and dracut can include
the required helper modules.
Reviewed-by: NPavel Shilovsky <pshilov@microsoft.com>
Signed-off-by: NJean Delvare <jdelvare@suse.de>
Cc: Steve French <sfrench@samba.org>

When a server returns the optional flag SMB_SHARE_IS_IN_DFS in response
to a tree connect, cifs_build_path_to_root() will return a pathname
which includes the hostname. This causes problems with cifs_get_root()
which separates each component and does a lookup for each component of
the path which in this case will incorrectly include looking up the
hostname component as a path component.

We encountered a problem with dfs shares hosted by a Netapp. When
connecting to nodes pointed to by the DFS share. The tree connect for
these nodes return SMB_SHARE_IS_IN_DFS resulting failures in lookup
in cifs_get_root().

RH bz: 1373153
The patch was tested against a Netapp simulator and by a user using an
actual Netapp server.
Signed-off-by: NSachin Prabhu <sprabhu@redhat.com>
Reported-by: NPierguido Lambri <plambri@redhat.com>
Reviewed-by: NJeff Layton <jlayton@redhat.com>
Signed-off-by: NSteve French <smfrench@gmail.com>

If .readlink == NULL implies generic_readlink().

Generated by:

to_del="\.readlink.*=.*generic_readlink"
for i in `git grep -l $to_del`; do sed -i "/$to_del"/d $i; done
Signed-off-by: NMiklos Szeredi <mszeredi@redhat.com>

Add "idsfromsid" mount option to indicate to cifs.ko that it should
try to retrieve the uid and gid owner fields from special sids in the
ACL if present.  This first patch just adds the parsing for the mount
option.
Signed-off-by: NSteve French <steve.french@primarydata.com>
Reviewed-by: NShirish Pargaonkar <shirishpargaonkar@gmail.com>
Reviewed-by: NPavel Shilovsky <pshilov@microsoft.com>

/sys/module/cifs/parameters should display the three
other module load time configuration settings for cifs.ko
Signed-off-by: NGermano Percossi <germano.percossi@citrix.com>
Signed-off-by: NSteve French <steve.french@primarydata.com>

Remove the global file_list_lock to simplify cifs/smb3 locking and
have spinlocks that more closely match the information they are
protecting.

Add new tcon->open_file_lock and file->file_info_lock spinlocks.
Locks continue to follow a heirachy,
	cifs_socket --> cifs_ses --> cifs_tcon --> cifs_file
where global tcp_ses_lock still protects socket and cifs_ses, while the
the newer locks protect the lower level structure's information
(tcon and cifs_file respectively).

CC: Stable <stable@vger.kernel.org>
Signed-off-by: NSteve French <steve.french@primarydata.com>
Signed-off-by: NPavel Shilovsky <pshilov@microsoft.com>
Reviewed-by: NAurelien Aptel <aaptel@suse.com>
Reviewed-by: NGermano Percossi <germano.percossi@citrix.com>

GUIDs although random, and 16 bytes, need to be generated as
proper uuids.
Signed-off-by: NSteve French <steve.french@primarydata.com>
Reviewed-by: NAurelien Aptel <aaptel@suse.com>
Reported-by: NDavid Goebels <davidgoe@microsoft.com>
CC: Stable <stable@vger.kernel.org>

These inode operations are no longer used; remove them.
Signed-off-by: NAndreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Generated patch:

sed -i "s/\.rename2\t/\.rename\t\t/" `git grep -wl rename2`
sed -i "s/\brename2\b/rename/g" `git grep -wl rename2`
Signed-off-by: NMiklos Szeredi <mszeredi@redhat.com>

Signed-off-by: NSachin Prabhu <sprabhu@redhat.com>
Tested-by: NAurelien Aptel <aaptel@suse.com>
Signed-off-by: NSteve French <smfrench@gmail.com>

Fix memory leaks introduced by the patch
fs/cifs: make share unaccessible at root level mountable

Also move allocation of cifs_sb->prepath to cifs_setup_cifs_sb().
Signed-off-by: NSachin Prabhu <sprabhu@redhat.com>
Tested-by: NAurelien Aptel <aaptel@suse.com>
Signed-off-by: NSteve French <smfrench@gmail.com>

if, when mounting //HOST/share/sub/dir/foo we can query /sub/dir/foo but
not any of the path components above:

- store the /sub/dir/foo prefix in the cifs super_block info
- in the superblock, set root dentry to the subpath dentry (instead of
  the share root)
- set a flag in the superblock to remember it
- use prefixpath when building path from a dentry

fixes bso#8950
Signed-off-by: NAurelien Aptel <aaptel@suse.com>
CC: Stable <stable@vger.kernel.org>
Reviewed-by: NPavel Shilovsky <pshilovsky@samba.org>
Signed-off-by: NSteve French <smfrench@gmail.com>

Right now, we send the tgid cross the wire. What we really want to send
though is a hashed fl_owner_t since samba treats this field as a generic
lockowner.

It turns out that because we enforce and release locks locally before
they are ever sent to the server, this patch makes no difference in
behavior. Still, setting OFD locks on the server using the process
pid seems wrong, so I think this patch still makes sense.
Signed-off-by: NJeff Layton <jlayton@poochiereds.net>
Signed-off-by: NSteve French <smfrench@gmail.com>
Acked-by: NPavel Shilovsky <pshilovsky@samba.org>
Acked-by: NSachin Prabhu <sprabhu@redhat.com>

Remove some obsolete comments in the cifs inode_operations
structs that were pointed out by Stephen Rothwell.

CC: Stephen Rothwell <sfr@canb.auug.org.au>
CC: Al Viro <viro@zeniv.linux.org.uk>
Reviewed-by: NSachin Prabhu <sprabhu@redhat.com>
Signed-off-by: NSteve French <steve.french@primarydata.com>

The session key is the default keyring set for request_key operations.
This session key is revoked when the user owning the session logs out.
Any long running daemon processes started by this session ends up with
revoked session keyring which prevents these processes from using the
request_key mechanism from obtaining the krb5 keys.

The problem has been reported by a large number of autofs users. The
problem is also seen with multiuser mounts where the share may be used
by processes run by a user who has since logged out. A reproducer using
automount is available on the Red Hat bz.

The patch creates a new keyring which is used to cache cifs spnego
upcalls.

Red Hat bz: 1267754
Signed-off-by: NSachin Prabhu <sprabhu@redhat.com>
Reported-by: NScott Mayhew <smayhew@redhat.com>
Reviewed-by: NShirish Pargaonkar <shirishpargaonkar@gmail.com>
CC: Stable <stable@vger.kernel.org>
Signed-off-by: NSteve French <smfrench@gmail.com>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Use xattr handlers for resolving attribute names.  The amount of setup
code required on cifs is nontrivial, so use the same get and set
functions for all handlers, with switch statements for the different
types of attributes in them.

The set_EA handler can handle NULL values, so we don't need a separate
removexattr function anymore.  Remove the cifs_dbg statements related to
xattr name resolution; they don't add much.  Don't build xattr.o when
CONFIG_CIFS_XATTR is not defined.
Signed-off-by: NAndreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time
ago with promise that one day it will be possible to implement page
cache with bigger chunks than PAGE_SIZE.

This promise never materialized.  And unlikely will.

We have many places where PAGE_CACHE_SIZE assumed to be equal to
PAGE_SIZE.  And it's constant source of confusion on whether
PAGE_CACHE_* or PAGE_* constant should be used in a particular case,
especially on the border between fs and mm.

Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much
breakage to be doable.

Let's stop pretending that pages in page cache are special.  They are
not.

The changes are pretty straight-forward:

 - <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>;

 - <foo> >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>;

 - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN};

 - page_cache_get() -> get_page();

 - page_cache_release() -> put_page();

This patch contains automated changes generated with coccinelle using
script below.  For some reason, coccinelle doesn't patch header files.
I've called spatch for them manually.

The only adjustment after coccinelle is revert of changes to
PAGE_CAHCE_ALIGN definition: we are going to drop it later.

There are few places in the code where coccinelle didn't reach.  I'll
fix them manually in a separate patch.  Comments and documentation also
will be addressed with the separate patch.

virtual patch

@@
expression E;
@@
- E << (PAGE_CACHE_SHIFT - PAGE_SHIFT)
+ E

@@
expression E;
@@
- E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT)
+ E

@@
@@
- PAGE_CACHE_SHIFT
+ PAGE_SHIFT

@@
@@
- PAGE_CACHE_SIZE
+ PAGE_SIZE

@@
@@
- PAGE_CACHE_MASK
+ PAGE_MASK

@@
expression E;
@@
- PAGE_CACHE_ALIGN(E)
+ PAGE_ALIGN(E)

@@
expression E;
@@
- page_cache_get(E)
+ get_page(E)

@@
expression E;
@@
- page_cache_release(E)
+ put_page(E)
Signed-off-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: NMichal Hocko <mhocko@suse.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Some callers of strtobool() were passing a pointer to unterminated
strings.  In preparation of adding multi-character processing to
kstrtobool(), update the callers to not pass single-character pointers,
and switch to using the new kstrtobool_from_user() helper where
possible.
Signed-off-by: NKees Cook <keescook@chromium.org>
Cc: Amitkumar Karwar <akarwar@marvell.com>
Cc: Nishant Sarmukadam <nishants@marvell.com>
Cc: Kalle Valo <kvalo@codeaurora.org>
Cc: Steve French <sfrench@samba.org>
Cc: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Joe Perches <joe@perches.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Commit 04b38d60 ("vfs: pull btrfs clone API to vfs layer")
added a duplicated line (in cifsfs.c) which causes a sparse compile
warning.
Signed-off-by: NSteve French <steve.french@primarydata.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>

parallel to mutex_{lock,unlock,trylock,is_locked,lock_nested},
inode_foo(inode) being mutex_foo(&inode->i_mutex).

Please, use those for access to ->i_mutex; over the coming cycle
->i_mutex will become rwsem, with ->lookup() done with it held
only shared.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Mark those kmem allocations that are known to be easily triggered from
userspace as __GFP_ACCOUNT/SLAB_ACCOUNT, which makes them accounted to
memcg.  For the list, see below:

 - threadinfo
 - task_struct
 - task_delay_info
 - pid
 - cred
 - mm_struct
 - vm_area_struct and vm_region (nommu)
 - anon_vma and anon_vma_chain
 - signal_struct
 - sighand_struct
 - fs_struct
 - files_struct
 - fdtable and fdtable->full_fds_bits
 - dentry and external_name
 - inode for all filesystems. This is the most tedious part, because
   most filesystems overwrite the alloc_inode method.

The list is far from complete, so feel free to add more objects.
Nevertheless, it should be close to "account everything" approach and
keep most workloads within bounds.  Malevolent users will be able to
breach the limit, but this was possible even with the former "account
everything" approach (simply because it did not account everything in
fact).

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: NVladimir Davydov <vdavydov@virtuozzo.com>
Acked-by: NJohannes Weiner <hannes@cmpxchg.org>
Acked-by: NMichal Hocko <mhocko@suse.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Greg Thelen <gthelen@google.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Currently O_DIRECT is supported with cache=none and cache=strict, but
not cache=loose. Add support for using O_DIRECT when mounted with
cache=loose.
Signed-off-by: NRoss Lagerwall <ross.lagerwall@citrix.com>
Signed-off-by: NSteve French <smfrench@gmail.com>

Currently the echo interval is set to 60 seconds using a macro. This
setting determines the interval at which echo requests are sent to the
server on an idling connection. This setting also affects the time
required for a connection to an unresponsive server to timeout.

Making this setting a tunable allows users to control the echo interval
times as well as control the time after which the connecting to an
unresponsive server times out.

To set echo interval, pass the echo_interval=n mount option.

Version four of the patch.
v2: Change MIN and MAX timeout values
v3: Remove incorrect comment in cifs_get_tcp_session
v4: Fix bug in setting echo_intervalw
Signed-off-by: NSachin Prabhu <sprabhu@redhat.com>
Acked-by: NShirish Pargaonkar <shirishpargaonkar@gmail.com>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

new method: ->get_link(); replacement of ->follow_link().  The differences
are:
	* inode and dentry are passed separately
	* might be called both in RCU and non-RCU mode;
the former is indicated by passing it a NULL dentry.
	* when called that way it isn't allowed to block
and should return ERR_PTR(-ECHILD) if it needs to be called
in non-RCU mode.

It's a flagday change - the old method is gone, all in-tree instances
converted.  Conversion isn't hard; said that, so far very few instances
do not immediately bail out when called in RCU mode.  That'll change
in the next commits.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

The newly introduced cifs_clone_file_range() function produces
two harmless compile-time warnings:

cifsfs.c: In function 'cifs_clone_file_range':
cifsfs.c:963:1: warning: label 'out_unlock' defined but not used [-Wunused-label]
cifsfs.c:924:20: warning: unused variable 'src_tcon' [-Wunused-variable]

In both cases, removing the extraneous line avoids the warning.
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Fixes: c6f2a1e2e5f8 ("vfs: pull btrfs clone API to vfs layer")
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

The btrfs clone ioctls are now adopted by other file systems, with NFS
and CIFS already having support for them, and XFS being under active
development.  To avoid growth of various slightly incompatible
implementations, add one to the VFS.  Note that clones are different from
file copies in several ways:

 - they are atomic vs other writers
 - they support whole file clones
 - they support 64-bit legth clones
 - they do not allow partial success (aka short writes)
 - clones are expected to be a fast metadata operation

Because of that it would be rather cumbersome to try to piggyback them on
top of the recent clone_file_range infrastructure.  The converse isn't
true and the clone_file_range system call could try clone file range as
a first attempt to copy, something that further patches will enable.

Based on earlier work from Peng Tao.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>