commit 4762cc3fbbd89e5fd316d6e4d3244a8984444f8d upstream.

We should be testing for -ENOMEM but the minus sign is missing.

Fixes: c9af28fdd449 ('ext4 crypto: don't let data integrity writebacks fail with ENOMEM')
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

commit c9af28fdd44922a6c10c9f8315718408af98e315 upstream.

We don't want the writeback triggered from the journal commit (in
data=writeback mode) to cause the journal to abort due to
generic_writepages() returning an ENOMEM error.  In addition, if
fsync() fails with ENOMEM, most applications will probably not do the
right thing.

So if we are doing a data integrity sync, and ext4_encrypt() returns
ENOMEM, we will submit any queued I/O to date, and then retry the
allocation using GFP_NOFAIL.

Google-Bug-Id: 27641567

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

There are times when ext4_bio_write_page() is called even though we
don't actually need to do any I/O.  This happens when ext4_writepage()
gets called by the jbd2 commit path when an inode needs to force its
pages written out in order to provide data=ordered guarantees --- and
a page is backed by an unwritten (e.g., uninitialized) block on disk,
or if delayed allocation means the page's backing store hasn't been
allocated yet.  In that case, we need to skip the call to
ext4_encrypt_page(), since in addition to wasting CPU, it leads to a
bounce page and an ext4 crypto context getting leaked.

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@vger.kernel.org

Pull ext4 updates from Ted Ts'o:
 "Pretty much all bug fixes and clean ups for 4.3, after a lot of
  features and other churn going into 4.2"

* tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4:
  Revert "ext4: remove block_device_ejected"
  ext4: ratelimit the file system mounted message
  ext4: silence a format string false positive
  ext4: simplify some code in read_mmp_block()
  ext4: don't manipulate recovery flag when freezing no-journal fs
  jbd2: limit number of reserved credits
  ext4 crypto: remove duplicate header file
  ext4: update c/mtime on truncate up
  jbd2: avoid infinite loop when destroying aborted journal
  ext4, jbd2: add REQ_FUA flag when recording an error in the superblock
  ext4 crypto: fix spelling typo in comment
  ext4 crypto: exit cleanly if ext4_derive_key_aes() fails
  ext4: reject journal options for ext2 mounts
  ext4: implement cgroup writeback support
  ext4: replace ext4_io_submit->io_op with ->io_wbc
  ext4 crypto: check for too-short encrypted file names
  ext4 crypto: use a jbd2 transaction when adding a crypto policy
  jbd2: speedup jbd2_journal_dirty_metadata()

We can always fill up the bio now, no need to estimate the possible
size based on queue parameters.

Acked-by: Steven Whitehouse <swhiteho@redhat.com>
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
[hch: rebased and wrote a changelog]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ming Lin <ming.l@ssi.samsung.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

Currently we have two different ways to signal an I/O error on a BIO:

 (1) by clearing the BIO_UPTODATE flag
 (2) by returning a Linux errno value to the bi_end_io callback

The first one has the drawback of only communicating a single possible
error (-EIO), and the second one has the drawback of not beeing persistent
when bios are queued up, and are not passed along from child to parent
bio in the ever more popular chaining scenario.  Having both mechanisms
available has the additional drawback of utterly confusing driver authors
and introducing bugs where various I/O submitters only deal with one of
them, and the others have to add boilerplate code to deal with both kinds
of error returns.

So add a new bi_error field to store an errno value directly in struct
bio and remove the existing mechanisms to clean all this up.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: NeilBrown <neilb@suse.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

For ordered and writeback data modes, all data IOs go through
ext4_io_submit.  This patch adds cgroup writeback support by invoking
wbc_init_bio() from io_submit_init_bio() and wbc_account_io() in
io_submit_add_bh().  Journal data which is written by jbd2 worker is
left alone by this patch and will always be written out from the root
cgroup.

ext4_fill_super() is updated to set MS_CGROUPWB when data mode is
either ordered or writeback.  In journaled data mode, most IOs become
synchronous through the journal and enabling cgroup writeback support
doesn't make much sense or difference.  Journaled data mode is left
alone.

Lightly tested with sequential data write workload.  Behaves as
expected.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

ext4_io_submit_init() takes the pointer to writeback_control to test
its sync_mode and determine between WRITE and WRITE_SYNC and records
the result in ->io_op.  This patch makes it record the pointer
directly and moves the test to ext4_io_submit().

This doesn't cause any noticeable differences now but having
writeback_control available throughout IO submission path will be
depended upon by the planned cgroup writeback support.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

Pull core block IO update from Jens Axboe:
 "Nothing really major in here, mostly a collection of smaller
  optimizations and cleanups, mixed with various fixes.  In more detail,
  this contains:

   - Addition of policy specific data to blkcg for block cgroups.  From
     Arianna Avanzini.

   - Various cleanups around command types from Christoph.

   - Cleanup of the suspend block I/O path from Christoph.

   - Plugging updates from Shaohua and Jeff Moyer, for blk-mq.

   - Eliminating atomic inc/dec of both remaining IO count and reference
     count in a bio.  From me.

   - Fixes for SG gap and chunk size support for data-less (discards)
     IO, so we can merge these better.  From me.

   - Small restructuring of blk-mq shared tag support, freeing drivers
     from iterating hardware queues.  From Keith Busch.

   - A few cfq-iosched tweaks, from Tahsin Erdogan and me.  Makes the
     IOPS mode the default for non-rotational storage"

* 'for-4.2/core' of git://git.kernel.dk/linux-block: (35 commits)
  cfq-iosched: fix other locations where blkcg_to_cfqgd() can return NULL
  cfq-iosched: fix sysfs oops when attempting to read unconfigured weights
  cfq-iosched: move group scheduling functions under ifdef
  cfq-iosched: fix the setting of IOPS mode on SSDs
  blktrace: Add blktrace.c to BLOCK LAYER in MAINTAINERS file
  block, cgroup: implement policy-specific per-blkcg data
  block: Make CFQ default to IOPS mode on SSDs
  block: add blk_set_queue_dying() to blkdev.h
  blk-mq: Shared tag enhancements
  block: don't honor chunk sizes for data-less IO
  block: only honor SG gap prevention for merges that contain data
  block: fix returnvar.cocci warnings
  block, dm: don't copy bios for request clones
  block: remove management of bi_remaining when restoring original bi_end_io
  block: replace trylock with mutex_lock in blkdev_reread_part()
  block: export blkdev_reread_part() and __blkdev_reread_part()
  suspend: simplify block I/O handling
  block: collapse bio bit space
  block: remove unused BIO_RW_BLOCK and BIO_EOF flags
  block: remove BIO_EOPNOTSUPP
  ...

Some fields are only used when the crypto_ctx is being used on the
read path, some are only used on the write path, and some are only
used when the structure is on free list.  Optimize memory use by using
a union.

Signed-off-by: Theodore Ts'o <tytso@mit.edu>