Fixes a data corruption under heavy stress in which pages could be left
dirty after all open instances of a inode have been closed.

In order to write contiguous pages whenever possible, cifs_writepages()
asks pagevec_lookup_tag() for more pages than it may write at one time.
Normally, it then resets index just past the last page written before calling
pagevec_lookup_tag() again.

If cifs_writepages() can't write the first page returned, it wasn't resetting
index, and the next call to pagevec_lookup_tag() resulted in skipping all of
the pages it previously returned, even though cifs_writepages() did nothing
with them.  This can result in data loss when the file descriptor is about
to be closed.

This patch ensures that index gets set back to the next returned page so
that none get skipped.
Signed-off-by: NDave Kleikamp <shaggy@linux.vnet.ibm.com>
Acked-by: NJeff Layton <jlayton@redhat.com>
Cc: Shirish S Pargaonkar <shirishp@us.ibm.com>
Signed-off-by: NSteve French <sfrench@us.ibm.com>

In preparation for Jeff's big umount/mount fixes to remove the possibility of
various races in cifs mount and linked list handling of sessions, sockets and
tree connections, this patch cleans up some repetitive code in cifs_mount,
and addresses a problem with ses->status and tcon->tidStatus in which we
were overloading the "need_reconnect" state with other status in that
field.  So the "need_reconnect" flag has been broken out from those
two state fields (need reconnect was not mutually exclusive from some of the
other possible tid and ses states).  In addition, a few exit cases in
cifs_mount were cleaned up, and a problem with a tcon flag (for lease support)
was not being set consistently for the 2nd mount of the same share

CC: Jeff Layton <jlayton@redhat.com>
CC: Shirish Pargaonkar <shirishp@us.ibm.com>
Signed-off-by: NSteve French <sfrench@us.ibm.com>

smb_send2 exit logic was strange, and with the previous change
could cause us to fail large
smb writes when all of the smb was not sent as one chunk.
Acked-by: NJeff Layton <jlayton@redhat.com>
Signed-off-by: NSteve French <sfrench@us.ibm.com>

Split the LRU lists in two, one set for pages that are backed by real file
systems ("file") and one for pages that are backed by memory and swap
("anon").  The latter includes tmpfs.

The advantage of doing this is that the VM will not have to scan over lots
of anonymous pages (which we generally do not want to swap out), just to
find the page cache pages that it should evict.

This patch has the infrastructure and a basic policy to balance how much
we scan the anon lists and how much we scan the file lists.  The big
policy changes are in separate patches.

[lee.schermerhorn@hp.com: collect lru meminfo statistics from correct offset]
[kosaki.motohiro@jp.fujitsu.com: prevent incorrect oom under split_lru]
[kosaki.motohiro@jp.fujitsu.com: fix pagevec_move_tail() doesn't treat unevictable page]
[hugh@veritas.com: memcg swapbacked pages active]
[hugh@veritas.com: splitlru: BDI_CAP_SWAP_BACKED]
[akpm@linux-foundation.org: fix /proc/vmstat units]
[nishimura@mxp.nes.nec.co.jp: memcg: fix handling of shmem migration]
[kosaki.motohiro@jp.fujitsu.com: adjust Quicklists field of /proc/meminfo]
[kosaki.motohiro@jp.fujitsu.com: fix style issue of get_scan_ratio()]
Signed-off-by: NRik van Riel <riel@redhat.com>
Signed-off-by: NLee Schermerhorn <Lee.Schermerhorn@hp.com>
Signed-off-by: NKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: NHugh Dickins <hugh@veritas.com>
Signed-off-by: NDaisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

cifs: Convert cifs to new aops.

This patch is based on the one originally posted by Nick Piggin. His
patch was very close, but had a couple of small bugs. Nick's original
comments follow:

This is another relatively naive conversion. Always do the read upfront
when the page is not uptodate (unless we're in the writethrough path).

Fix an uninitialized data exposure where SetPageUptodate was called
before the page was uptodate.

SetPageUptodate and switch to writeback mode in the case that the full
page was dirtied.
Acked-by: NShaggy <shaggy@austin.ibm.com>
Acked-by: NBadari Pulavarty <pbadari@us.ibm.com>
Signed-off-by: NNick Piggin <npiggin@suse.de>
Signed-off-by: NJeff Layton <jlayton@redhat.com>
Signed-off-by: NSteve French <sfrench@us.ibm.com>

When the CIFS client goes to write out pages, it needs to pick a
filehandle to write to. find_writeable_file however just picks the
first filehandle that it finds. This can cause problems when a lock
is issued against a particular filehandle and we pick a different
filehandle to write to.

This patch tries to avert this situation by having find_writable_file
prefer filehandles that have a pid that matches the current task.
This seems to fix lock test 11 from the connectathon test suite when
run against a windows server.
Signed-off-by: NJeff Layton <jlayton@redhat.com>
Signed-off-by: NSteve French <sfrench@us.ibm.com>

The direct I/O write codepath for CIFS is done through
cifs_user_write(). That function does not currently call
generic_write_checks() so the file position isn't being properly set
when the file is opened with O_APPEND.  It's also not doing the other
"normal" checks that should be done for a write call.

The problem is currently that when you open a file with O_APPEND on a
mount with the directio mount option, the file position is set to the
beginning of the file. This makes any subsequent writes clobber the data
in the file starting at the beginning.

This seems to fix the problem in cursory testing. It is, however
important to note that NFS disallows the combination of
(O_DIRECT|O_APPEND). If my understanding is correct, the concern is
races with multiple clients appending to a file clobbering each others'
data. Since the write model for CIFS and NFS is pretty similar in this
regard, CIFS is probably subject to the same sort of races. What's
unclear to me is why this is a particular problem with O_DIRECT and not
with buffered writes...

Regardless, disallowing O_APPEND on an entire mount is probably not
reasonable, so we'll probably just have to deal with it and reevaluate
this flag combination when we get proper support for O_DIRECT. In the
meantime this patch at least fixes the existing problem.
Signed-off-by: NJeff Layton <jlayton@redhat.com>
Cc: Stable Tree <stable@kernel.org>
Signed-off-by: NSteve French <sfrench@us.ibm.com>

We'd like to be able to use the unix SET_PATH_INFO_BASIC args to set
file times as well, but that makes the argument list rather long. Bundle
up the args for unix SET_PATH_INFO call into a struct. For now, we don't
actually use the times fields anywhere. That will be done in a follow-on
patch.
Signed-off-by: NJeff Layton <jlayton@redhat.com>
Signed-off-by: NSteve French <sfrench@us.ibm.com>

Converting page lock to new locking bitops requires a change of page flag
operation naming, so we might as well convert it to something nicer
(!TestSetPageLocked_Lock => trylock_page, SetPageLocked => set_page_locked).

This also facilitates lockdeping of page lock.
Signed-off-by: NNick Piggin <npiggin@suse.de>
Acked-by: NKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: NPeter Zijlstra <peterz@infradead.org>
Acked-by: NAndrew Morton <akpm@linux-foundation.org>
Acked-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

CC: Jeff Layton <jlayton@redhat.com>
Signed-off-by: NSteve French <sfrench@us.ibm.com>

cifs_convert_flags returns 0x20197 in the default case. It's not
immediately evident where that number comes from, so change it
to be an or'ed set of flags. The compiler will boil it down anyway.

(Thanks to Guenter Kukkukk for clarifying the flags).
Signed-off-by: NSteve French <sfrench@us.ibm.com>

Signed-off-by: NJoe Perches <joe@perches.com>
Signed-off-by: NSteve French <sfrench@us.ibm.com>

Shirish Pargaonkar noted:
With cifsacl mount option, when a file is created on the Windows server,
exclusive oplock is broken right away because the get cifs acl code
again opens the file to obtain security descriptor.
The client does not have the newly created file handle or inode in any
of its lists yet so it does not respond to oplock break and server waits for
its duration and then responds to the second open. This slows down file
creation signficantly.  The fix is to pass the file descriptor to the get
cifsacl code wherever available so that get cifs acl code does not send
second open (NT Create ANDX) and oplock is not broken.

CC: Shirish Pargaonkar <shirishp@us.ibm.com>
Signed-off-by: NSteve French <sfrench@us.ibm.com>

Christoph had noticed too many ifdefs in the CIFS code making it
hard to read.  This patch removes about a quarter of them from
the C files in cifs by improving a few key ifdefs in the .h files.
Signed-off-by: NSteve French <sfrench@us.ibm.com>

Signed-off-by: NSteve French <sfrench@us.ibm.com>

rc cannot be -EBADF now and condition is always true
Signed-off-by: NVasily Averin <vvs@sw.ru>
Signed-off-by: NSteve French <sfrench@us.ibm.com>

Fix RedHat bug 329431

The idea here is separate "conscious" from "unconscious" flushes.
Conscious flushes are those due to a fsync() or close(). Unconscious
ones are flushes that occur as a side effect of some other operation or
due to memory pressure.

Currently, when an error occurs during an unconscious flush (ENOSPC or
EIO), we toss out the page and don't preserve that error to report to
the user when a conscious flush occurs. If after the unconscious flush,
there are no more dirty pages for the inode, the conscious flush will
simply return success even though there were previous errors when writing
out pages. This can lead to data corruption.

The easiest way to reproduce this is to mount up a CIFS share that's
very close to being full or where the user is very close to quota. mv
a file to the share that's slightly larger than the quota allows. The
writes will all succeed (since they go to pagecache). The mv will do a
setattr to set the new file's attributes. This calls
filemap_write_and_wait,
which will return an error since all of the pages can't be written out.
Then later, when the flush and release ops occur, there are no more
dirty pages in pagecache for the file and those operations return 0. mv
then assumes that the file was written out correctly and deletes the
original.

CIFS already has a write_behind_rc variable where it stores the results
from earlier flushes, but that value is only reported in cifs_close.
Since the VFS ignores the return value from the release operation, this
isn't helpful. We should be reporting this error during the flush
operation.

This patch does the following:

1) changes cifs_fsync to use filemap_write_and_wait and cifs_flush and also
sync to check its return code. If it returns successful, they then check
the value of write_behind_rc to see if an earlier flush had reported any
errors. If so, they return that error and clear write_behind_rc.

2) sets write_behind_rc in a few other places where pages are written
out as a side effect of other operations and the code waits on them.

3) changes cifs_setattr to only call filemap_write_and_wait for
ATTR_SIZE changes.

4) makes cifs_writepages accurately distinguish between EIO and ENOSPC
errors when writing out pages.

Some simple testing indicates that the patch works as expected and that
it fixes the reproduceable known problem.
Acked-by: NDave Kleikamp <shaggy@austin.rr.com>
Signed-off-by: NJeff Layton <jlayton@redhat.com>
Signed-off-by: NSteve French <sfrench@us.ibm.com>

Signed-off-by: NSteve French <sfrench@us.ibm.com>

request

In SendReceive() function in transport.c - it memcpy's
message payload into a buffer passed via out_buf param. The function
assumes that all buffers are of size (CIFSMaxBufSize +
MAX_CIFS_HDR_SIZE) , unfortunately it is also called with smaller
(MAX_CIFS_SMALL_BUFFER_SIZE) buffers.  There are eight callers
(SMB worker functions) which are primarily affected by this change:

TreeDisconnect, uLogoff, Close, findClose, SetFileSize, SetFileTimes,
Lock and PosixLock

CC: Dave Kleikamp <shaggy@austin.ibm.com>
CC: Przemyslaw Wegrzyn <czajnik@czajsoft.pl>
Acked-by: NJeff Layton <jlayton@redhat.com>
Signed-off-by: NSteve French <sfrench@us.ibm.com>

Acked-by: NShirish Pargaonkar <shirishp@us.ibm.com>
CC: Cyrill Gorcunov <gorcunov@gmail.com>
Signed-off-by: NSteve French <sfrench@us.ibm.com>

Signed-off-by: NCyrill Gorcunov <gorcunov@gmail.com>
Signed-off-by: NSteve French <sfrench@us.ibm.com>

When find_writable_file is racing with close and the session
to the server goes down, Shaggy noticed that there was a
chance that an open file in the list of files off the inode
could have been freed by close since cifs_reconnect can
block (the spinlock thus not held). This means that
we have to start over at the beginning of the list in some
cases.

There is a 2nd change that needs to be made later
(pointed out by Jeremy Allison and Shaggy) in order to
prevent cifs_close ever freeing the cifs per file info
when a write is pending.  Although we delay close from
freeing this memory for sufficiently long for all known
cases, ultimately on a very, very slow write
overlapping a close pending we need to allow close to return
(without freeing the cifs file info) and defer freeing the
memory to be the responsibility of the (sloooow) write
thread (presumably have to look at every place wrtPending
is decremented - and add a flag for deferred free for
after wrtPending goes to zero).
Acked-by: NShaggy <shaggy@us.ibm.com>
Acked-by: NShirish Pargaonkar <shirishp@us.ibm.com>
Signed-off-by: NSteve French <sfrench@us.ibm.com>

Harmless since it only protected turning off caching for the
inode, but cleaner to lock around this in case we have a close
racing with open.
Signed-off-by: NShaggy <shaggy@us.ibm.com>
CC: Cyrill Gorcunov <gorcunov@gmail.com>
Signed-off-by: NSteve French <sfrench@us.ibm.com>

There was a case in which find_writable_file was not waiting long enough
under heavy stress when writepages was racing with close of the file
handle being used by the write.
Signed-off-by: NSteve French <sfrench@us.ibm.com>

Signed-off-by: NSteve French <sfrench@us.ibm.com>

On a mount without posix extensions enabled, when an unlock request is
made, the client can release more than is intended. To reproduce, on a
CIFS mount without posix extensions enabled:

1) open file
2) do fcntl lock: start=0 len=1
3) do fcntl lock: start=2 len=1
4) do fcntl unlock: start=0 len=1

...on the unlock call the client sends an unlock request to the server
for both locks. The problem is a bad test in cifs_lock.
Signed-off-by: NJeff Layton <jlayton@redhat.com>
Signed-off-by: NSteve French <sfrench@us.ibm.com>

Caused by unneeded reopen during reconnect while spinlock held.

Fixes kernel bugzilla bug #7903

Thanks to Lin Feng Shen for testing this, and Amit Arora for
some nice problem determination to narrow this down.
Acked-by: NDave Kleikamp <shaggy@us.ibm.com>
Signed-off-by: NSteve French <sfrench@us.ibm.com>

Previously the only way to do this was to umount all mounts to that server,
turn off a proc setting (/proc/fs/cifs/LinuxExtensionsEnabled).

Fixes Samba bugzilla bug number: 4582 (and also 2008)
Signed-off-by: NSteve French <sfrench@us.ibm.com>

Signed-off-by: NSteve French <sfrench@us.ibm.com>

It's common for file systems to need to zero data on either side of a
write, if a page is not Uptodate during prepare_write.  It just so happens
that simple_prepare_write() in libfs.c does exactly that, so we can avoid
duplication and just call that function to zero page data.
Signed-off-by: NNate Diller <nate.diller@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NSteve French <sfrench@us.ibm.com>

This should be the last big batch of whitespace/formatting fixes.
checkpatch warnings for the cifs directory are down about 90% and
many of the remaining ones are harder to remove or make the code
harder to read.
Signed-off-by: NSteve French <sfrench@us.ibm.com>

nfsd is passing null nameidata (probably the only one doing that)
on call to create - cifs was missing one check for this.

Note that running nfsd over a cifs mount requires specifying fsid on
the nfs exports entry and requires mounting cifs with serverino mount
option.
Signed-off-by: NSteve French <sfrench@us.ibm.com>

More than halfway there
Signed-off-by: NSteve French <sfrench@us.ibm.com>

Signed-off-by: NSteve French <sfrench@us.ibm.com>

Remove includes of <linux/smp_lock.h> where it is not used/needed.
Suggested by Al Viro.

Builds cleanly on x86_64, i386, alpha, ia64, powerpc, sparc,
sparc64, and arm (all 59 defconfigs).
Signed-off-by: NRandy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Originally at http://lkml.org/lkml/2006/9/2/86

The recent change to "allow Windows blocking locks to be cancelled via a
CANCEL_LOCK call" introduced a new semaphore in struct cifsFileInfo,
lock_sem.  However, semaphores used as mutexes are deprecated these days,
and there's no reason to add a new one to the kernel.  Therefore, convert
lock_sem to a struct mutex (and also fix one indentation glitch on one of
the lines changed anyway).
Signed-off-by: NRoland Dreier <roland@digitalvampire.org>
Signed-off-by: NJan Engelhardt <jengelh@gmx.de>
Signed-off-by: NSteve French <sfrench@us.ibm.com>

Also expand debug entry to show which character on a failed Unicode
mapping.
Acked-by: NShaggy <shaggy@us.ibm.com>
Signed-off-by: NSteve French <sfrench@us.ibm.com>

file->f_path.dentry or file->f_path.dentry.d_inode can't be NULL since at
least ten years, similar for all but very few arguments passed in from the
VFS.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NSteve French <sfrench@us.ibm.com>

Noticed by Shaggy.
Signed-off-by: NShaggy <shaggy@us.ibm.com>
Signed-off-by: NSteve French <sfrench@us.ibm.com>

Could cause hangs on smp systems in i_size_read on a cifs inode
whose size has been previously simultaneously updated from
different processes.

Thanks to Brian Wang for some great testing/debugging on this
hard problem.

Fixes kernel bugzilla #7903

CC: Shirish Pargoankar <shirishp@us.ibm.com>
CC: Shaggy <shaggy@us.ibm.com>
Signed-off-by: NSteve French <sfrench@us.ibm.com>