fs: Protect write paths by sb_start_write - sb_end_write

There are several entry points which dirty pages in a filesystem.  mmap
(handled by block_page_mkwrite()), buffered write (handled by
__generic_file_aio_write()), splice write (generic_file_splice_write),
truncate, and fallocate (these can dirty last partial page - handled inside
each filesystem separately). Protect these places with sb_start_write() and
sb_end_write().

->page_mkwrite() calls are particularly complex since they are called with
mmap_sem held and thus we cannot use standard sb_start_write() due to lock
ordering constraints. We solve the problem by using a special freeze protection
sb_start_pagefault() which ranks below mmap_sem.

BugLink: https://bugs.launchpad.net/bugs/897421
Tested-by: Kamal Mostafa <kamal@canonical.com>
Tested-by: Peter M. Petrakis <peter.petrakis@canonical.com>
Tested-by: Dann Frazier <dann.frazier@canonical.com>
Tested-by: Massimo Morana <massimo.morana@canonical.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
ext4: Convert to new freezing mechanism

We remove most of frozen checks since upper layer takes care of blocking all
writes. We have to handle protection in ext4_page_mkwrite() in a special way
because we cannot use generic block_page_mkwrite(). Also we add a freeze
protection to ext4_evict_inode() so that iput() of unlinked inode cannot modify
a frozen filesystem (we cannot easily instrument ext4_journal_start() /
ext4_journal_stop() with freeze protection because we are missing the
superblock pointer in ext4_journal_stop() in nojournal mode).

CC: linux-ext4@vger.kernel.org
CC: "Theodore Ts'o" <tytso@mit.edu>
BugLink: https://bugs.launchpad.net/bugs/897421
Tested-by: Kamal Mostafa <kamal@canonical.com>
Tested-by: Peter M. Petrakis <peter.petrakis@canonical.com>
Tested-by: Dann Frazier <dann.frazier@canonical.com>
Tested-by: Massimo Morana <massimo.morana@canonical.com>
Acked-by: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
xfs: Convert to new freezing code

Generic code now blocks all writers from standard write paths. So we add
blocking of all writers coming from ioctl (we get a protection of ioctl against
racing remount read-only as a bonus) and convert xfs_file_aio_write() to a
non-racy freeze protection. We also keep freeze protection on transaction
start to block internal filesystem writes such as removal of preallocated
blocks.

CC: Ben Myers <bpm@sgi.com>
CC: Alex Elder <elder@kernel.org>
CC: xfs@oss.sgi.com
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
ocfs2: Convert to new freezing mechanism

Protect ocfs2_page_mkwrite() and ocfs2_file_aio_write() using the new freeze
protection. We also protect several ioctl entry points which were missing the
protection. Finally, we add freeze protection to the journaling mechanism so
that iput() of unlinked inode cannot modify a frozen filesystem.

CC: Mark Fasheh <mfasheh@suse.com>
CC: Joel Becker <jlbec@evilplan.org>
CC: ocfs2-devel@oss.oracle.com
Acked-by: Joel Becker <jlbec@evilplan.org>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
gfs2: Convert to new freezing mechanism

We update gfs2_page_mkwrite() to use new freeze protection and the transaction
code to use freeze protection while the transaction is running. That is needed
to stop iput() of unlinked file from modifying the filesystem. The rest is
handled by the generic code.

CC: cluster-devel@redhat.com
CC: Steven Whitehouse <swhiteho@redhat.com>
Acked-by: Steven Whitehouse <swhiteho@redhat.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
fuse: Convert to new freezing mechanism

Convert check in fuse_file_aio_write() to using new freeze protection.

CC: fuse-devel@lists.sourceforge.net
CC: Miklos Szeredi <miklos@szeredi.hu>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
ntfs: Convert to new freezing mechanism

Move check in ntfs_file_aio_write_nolock() to ntfs_file_aio_write() and
use new freeze protection.

CC: linux-ntfs-dev@lists.sourceforge.net
CC: Anton Altaparmakov <anton@tuxera.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
nilfs2: Convert to new freezing mechanism

We change nilfs_page_mkwrite() to provide proper freeze protection for
writeable page faults (we must wait for frozen filesystem even if the
page is fully mapped).

We remove all vfs_check_frozen() checks since they are now handled by
the generic code.

CC: linux-nilfs@vger.kernel.org
CC: KONISHI Ryusuke <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
btrfs: Convert to new freezing mechanism

We convert btrfs_file_aio_write() to use new freeze check.  We also add proper
freeze protection to btrfs_page_mkwrite(). We also add freeze protection to
the transaction mechanism to avoid starting transactions on frozen filesystem.
At minimum this is necessary to stop iput() of unlinked file to change frozen
filesystem during truncation.

Checks in cleaner_kthread() and transaction_kthread() can be safely removed
since btrfs_freeze() will lock the mutexes and thus block the threads (and they
shouldn't have anything to do anyway).

CC: linux-btrfs@vger.kernel.org
CC: Chris Mason <chris.mason@oracle.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
ext2: Implement freezing

The only missing piece to make freezing work reliably with ext2 is to
stop iput() of unlinked inode from deleting the inode on frozen filesystem.
So add a necessary protection to ext2_evict_inode().

We also provide appropriate ->freeze_fs and ->unfreeze_fs functions.

Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
fs: Remove old freezing mechanism

Now that all users are converted, we can remove functions, variables, and
constants defined by the old freezing mechanism.

BugLink: https://bugs.launchpad.net/bugs/897421
Tested-by: Kamal Mostafa <kamal@canonical.com>
Tested-by: Peter M. Petrakis <peter.petrakis@canonical.com>
Tested-by: Dann Frazier <dann.frazier@canonical.com>
Tested-by: Massimo Morana <massimo.morana@canonical.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Documentation: Correct s_umount state for freeze_fs/unfreeze_fs

freeze_fs/unfreeze_fs ops are called with s_umount held for write, not read.

Signed-off-by: Valerie Aurora <val@vaaconsulting.com>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
block/nbd: micro-optimization in nbd request completion

Add in-flight cmds to the tail. That way while searching
(during request completion),we will always get a hit on the
first element.

Signed-off-by: Chetan Loke <loke.chetan@gmail.com>
Acked-by: Paul.Clements@steeleye.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
md: remove plug_cnt feature of plugging.

This seemed like a good idea at the time, but after further thought I
cannot see it making a difference other than very occasionally and
testing to try to exercise the case it is most likely to help did not
show any performance difference by removing it.

So remove the counting of active plugs and allow 'pending writes' to
be activated at any time, not just when no plugs are active.

This is only relevant when there is a write-intent bitmap, and the
updating of the bitmap will likely introduce enough delay that
the single-threading of bitmap updates will be enough to collect large
numbers of updates together.

Removing this will make it easier to centralise the unplug code, and
will clear the other for other unplug enhancements which have a
measurable effect.

Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
blk: centralize non-request unplug handling.

Both md and umem has similar code for getting notified on an
blk_finish_plug event.
Centralize this code in block/ and allow each driver to
provide its distinctive difference.

Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
block: stack unplug

MD raid1 prepares to dispatch request in unplug callback. If make_request in
low level queue also uses unplug callback to dispatch request, the low level
queue's unplug callback will not be called. Recheck the callback list helps
this case.

Signed-off-by: Shaohua Li <shli@fusionio.com>
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
blk: pass from_schedule to non-request unplug functions.

This will allow md/raid to know why the unplug was called,
and will be able to act according - if !from_schedule it
is safe to perform tasks which could themselves schedule.

Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
ALSA: hda - Fix polarity of mute LED on HP Mini 210

The commit a3e199732b made the LED working again on HP Mini 210 but
with a wrong polarity.  This patch fixes the polarity for this
machine, and also introduce a new model string "hp-inv-led".

Bugzilla: https://bugzilla.novell.com/show_bug.cgi?id=772923

Cc: <stable@vger.kernel.org> [v3.3+]
Signed-off-by: Takashi Iwai <tiwai@suse.de>
ALSA: hda - Add descriptions for missing IDT 92HD83x models

Signed-off-by: Takashi Iwai <tiwai@suse.de>
ALSA: hda - Fix mute-LED GPIO initialization for IDT codecs

The IDT codecs initializes the GPIO setup for mute LEDs via
snd_hda_sync_vmaster_hook().  This works in most cases except for the
very first call, which is called before PCM and control creations.
Thus before Master switch is set manually via alsactl, the mute LED
may show the wrong state, depending on the polarity.

Now it's fixed by calling the LED-status update function manually when
no vmaster is set yet.

Cc: <stable@vger.kernel.org> [v3.4+]
Signed-off-by: Takashi Iwai <tiwai@suse.de>