Cc: cluster-devel@redhat.com
Signed-off-by: NFabian Frederick <fabf@skynet.be>
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

Signed-off-by: NGeert Uytterhoeven <geert@linux-m68k.org>
Cc: cluster-devel@redhat.com
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

This patch removes the GLF_NOCACHE flag from the glocks associated with
flocks. There should be no good reason not to cache glocks for flocks:
they only force the glock to be demoted before they can be reacquired,
which can slow down performance and even cause glock hangs, especially
in cases where the flocks are held in Shared (SH) mode.
Signed-off-by: NBob Peterson <rpeterso@redhat.com>
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

This patch allows flock glocks to use a non-blocking dequeue rather
than dq_wait. It also reverts the previous patch I had posted regarding
dq_wait. The reverted patch isn't necessarily a bad idea, but I decided
this might avoid unforeseen side effects, and was therefore safer.
Signed-off-by: NBob Peterson <rpeterso@redhat.com>
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

kcalloc manages count*sizeof overflow.

Cc: cluster-devel@redhat.com
Signed-off-by: NFabian Frederick <fabf@skynet.be>
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

Normally GFP_KERNEL is ok here, but there is now a rarely used code path
relating to deallocation of unlinked inodes (in certain corner cases)
which if hit at times of memory shortage can cause recursion while
trying to free memory.

One solution would be to try and move the gfs2_glock_get() call so
that it is no longer called while another glock is held, but that
doesn't look at all easy, so GFP_NOFS is the best solution for the
time being.
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

We must not leave items on the LRU list with GLF_LOCK set, since
they can be removed if the glock is brought back into use, which
may then potentially result in a hang, waiting for GLF_LOCK to
clear.

It doesn't happen very often, since it requires a glock that has
not been used for a long time to be brought back into use at the
same moment that the shrinker is part way through disposing of
glocks.

The fix is to set GLF_LOCK at a later time, when we already know
that the other locks can be obtained. Also, we now only release
the lru_lock in case a resched is needed, rather than on every
iteration.
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

Function gfs2_glock_dq_wait is supposed to dequeue a glock and then
wait for the lock to be demoted. The problem is, if this is a shared
lock, its demote will depend on the other holders, which means you
might end up waiting forever because the other process is blocked.
This problem is especially apparent when dealing with nested flocks.
Signed-off-by: NBob Peterson <rpeterso@redhat.com>
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

Commit 1ab6c499 (fs: convert fs shrinkers to new scan/count API)
accidentally removed locking from quota shrinker. Fix it -
dqcache_shrink_scan() should use dq_list_lock to protect the
scan on free_dquots list.

CC: stable@vger.kernel.org
Fixes: 1ab6c499Signed-off-by: NNiu Yawei <yawei.niu@intel.com>
Signed-off-by: NJan Kara <jack@suse.cz>

When quota is on, it is expected that unused quota inodes have a
value of NULLFSINO. The changes to support a separate project quota
in 3.12 broken this rule for non-project quota inode enabled
filesystem, as the code now refuses to write the group quota inode
if neither group or project quotas are enabled. This regression was
introduced by commit d892d586 ("xfs: Start using pquotaino from the
superblock").

In this case, we should be writing NULLFSINO rather than nothing to
ensure that we leave the group quota inode in a valid state while
quotas are enabled.

Failure to do so doesn't cause a current kernel to break - the
separate project quota inodes introduced translation code to always
treat a zero inode as NULLFSINO. This was introduced by commit
01026297 ("xfs: Initialize all quota inodes to be NULLFSINO") with is
also in 3.12 but older kernels do not do this and hence taking a
filesystem back to an older kernel can result in quotas failing
initialisation at mount time. When that happens, we see this in
dmesg:

[ 1649.215390] XFS (sdb): Mounting Filesystem
[ 1649.316894] XFS (sdb): Failed to initialize disk quotas.
[ 1649.316902] XFS (sdb): Ending clean mount

By ensuring that we write NULLFSINO to quota inodes that aren't
active, we avoid this problem. We have to be really careful when
determining if the quota inodes are active or not, because we don't
want to write a NULLFSINO if the quota inodes are active and we
simply aren't updating them.
Signed-off-by: NDave Chinner <dchinner@redhat.com>
Reviewed-by: NBrian Foster <bfoster@redhat.com>
Signed-off-by: NDave Chinner <david@fromorbit.com>

The allocation stack switch at xfs_bmapi_allocate() has served it's
purpose, but is no longer a sufficient solution to the stack usage
problem we have in the XFS allocation path.

Whilst the kernel stack size is now 16k, that is not a valid reason
for undoing all our "keep stack usage down" modifications. What it
does allow us to do is have the freedom to refine and perfect the
modifications knowing that if we get it wrong it won't blow up in
our faces - we have a safety net now.

This is important because we still have the issue of older kernels
having smaller stacks and that they are still supported and are
demonstrating a wide range of different stack overflows.  Red Hat
has several open bugs for allocation based stack overflows from
directory modifications and direct IO block allocation and these
problems still need to be solved. If we can solve them upstream,
then distro's won't need to bake their own unique solutions.

To that end, I've observed that every allocation based stack
overflow report has had a specific characteristic - it has happened
during or directly after a bmap btree block split. That event
requires a new block to be allocated to the tree, and so we
effectively stack one allocation stack on top of another, and that's
when we get into trouble.

A further observation is that bmap btree block splits are much rarer
than writeback allocation - over a range of different workloads I've
observed the ratio of bmap btree inserts to splits ranges from 100:1
(xfstests run) to 10000:1 (local VM image server with sparse files
that range in the hundreds of thousands to millions of extents).
Either way, bmap btree split events are much, much rarer than
allocation events.

Finally, we have to move the kswapd state to the allocation workqueue
work when allocation is done on behalf of kswapd. This is proving to
cause significant perturbation in performance under memory pressure
and appears to be generating allocation deadlock warnings under some
workloads, so avoiding the use of a workqueue for the majority of
kswapd writeback allocation will minimise the impact of such
behaviour.

Hence it makes sense to move the stack switch to xfs_btree_split()
and only do it for bmap btree splits. Stack switches during
allocation will be much rarer, so there won't be significant
performacne overhead caused by switching stacks. The worse case
stack from all allocation paths will be split, not just writeback.
And the majority of memory allocations will be done in the correct
context (e.g. kswapd) without causing additional latency, and so we
simplify the memory reclaim interactions between processes,
workqueues and kswapd.

The worst stack I've been able to generate with this patch in place
is 5600 bytes deep. It's very revealing because we exit XFS at:

37)     1768      64   kmem_cache_alloc+0x13b/0x170

about 1800 bytes of stack consumed, and the remaining 3800 bytes
(and 36 functions) is memory reclaim, swap and the IO stack. And
this occurs in the inode allocation from an open(O_CREAT) syscall,
not writeback.

The amount of stack being used is much less than I've previously be
able to generate - fs_mark testing has been able to generate stack
usage of around 7k without too much trouble; with this patch it's
only just getting to 5.5k. This is primarily because the metadata
allocation paths (e.g. directory blocks) are no longer causing
double splits on the same stack, and hence now stack tracing is
showing swapping being the worst stack consumer rather than XFS.

Performance of fs_mark inode create workloads is unchanged.
Performance of fs_mark async fsync workloads is consistently good
with context switches reduced by around 150,000/s (30%).
Performance of dbench, streaming IO and postmark is unchanged.
Allocation deadlock warnings have not been seen on the workloads
that generated them since adding this patch.
Signed-off-by: NDave Chinner <dchinner@redhat.com>
Reviewed-by: NBrian Foster <bfoster@redhat.com>
Signed-off-by: NDave Chinner <david@fromorbit.com>

This reverts commit 1f6d6482.

This commit resulted in regressions in performance in low
memory situations where kswapd was doing writeback of delayed
allocation blocks. It resulted in significant parallelism of the
kswapd work and with the special kswapd flags meant that hundreds of
active allocation could dip into kswapd specific memory reserves and
avoid being throttled. This cause a large amount of performance
variation, as well as random OOM-killer invocations that didn't
previously exist.
Signed-off-by: NDave Chinner <dchinner@redhat.com>
Reviewed-by: NBrian Foster <bfoster@redhat.com>
Signed-off-by: NDave Chinner <david@fromorbit.com>

As of commit f8567a38 it is now possible to
have put_reqs_available() called from irq context.  While put_reqs_available()
is per cpu, it did not protect itself from interrupts on the same CPU.  This
lead to aio_complete() corrupting the available io requests count when run
under a heavy O_DIRECT workloads as reported by Robert Elliott.  Fix this by
disabling irq updates around the per cpu batch updates of reqs_available.

Many thanks to Robert and folks for testing and tracking this down.
Reported-by: NRobert Elliot <Elliott@hp.com>
Tested-by: NRobert Elliot <Elliott@hp.com>
Signed-off-by: NBenjamin LaHaise <bcrl@kvack.org>
Cc: Jens Axboe <axboe@kernel.dk>, Christoph Hellwig <hch@infradead.org>
Cc: stable@vger.kenel.org

kcalloc manages count*sizeof overflow.
Signed-off-by: NFabian Frederick <fabf@skynet.be>
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>

tmp_page to be freed if fuse_write_file_get() returns NULL.
Signed-off-by: NMaxim Patlasov <mpatlasov@parallels.com>
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>

Fix potential null pointer dereferencing problem caused by e43bb4e6
("ext4: decrement free clusters/inodes counters when block group declared bad")
Reported-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NNamjae Jeon <namjae.jeon@samsung.com>
Signed-off-by: NAshish Sangwan <a.sangwan@samsung.com>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>
Reviewed-by: NLukas Czerner <lczerner@redhat.com>

This fixes the following lockdep complaint:

[ INFO: possible circular locking dependency detected ]
3.16.0-rc2-mm1+ #7 Tainted: G           O  
-------------------------------------------------------
kworker/u24:0/4356 is trying to acquire lock:
 (&(&sbi->s_es_lru_lock)->rlock){+.+.-.}, at: [<ffffffff81285fff>] __ext4_es_shrink+0x4f/0x2e0

but task is already holding lock:
 (&ei->i_es_lock){++++-.}, at: [<ffffffff81286961>] ext4_es_insert_extent+0x71/0x180

which lock already depends on the new lock.

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&ei->i_es_lock);
                               lock(&(&sbi->s_es_lru_lock)->rlock);
                               lock(&ei->i_es_lock);
  lock(&(&sbi->s_es_lru_lock)->rlock);

 *** DEADLOCK ***

6 locks held by kworker/u24:0/4356:
 #0:  ("writeback"){.+.+.+}, at: [<ffffffff81071d00>] process_one_work+0x180/0x560
 #1:  ((&(&wb->dwork)->work)){+.+.+.}, at: [<ffffffff81071d00>] process_one_work+0x180/0x560
 #2:  (&type->s_umount_key#22){++++++}, at: [<ffffffff811a9c74>] grab_super_passive+0x44/0x90
 #3:  (jbd2_handle){+.+...}, at: [<ffffffff812979f9>] start_this_handle+0x189/0x5f0
 #4:  (&ei->i_data_sem){++++..}, at: [<ffffffff81247062>] ext4_map_blocks+0x132/0x550
 #5:  (&ei->i_es_lock){++++-.}, at: [<ffffffff81286961>] ext4_es_insert_extent+0x71/0x180

stack backtrace:
CPU: 0 PID: 4356 Comm: kworker/u24:0 Tainted: G           O   3.16.0-rc2-mm1+ #7
Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
Workqueue: writeback bdi_writeback_workfn (flush-253:0)
 ffffffff8213dce0 ffff880014b07538 ffffffff815df0bb 0000000000000007
 ffffffff8213e040 ffff880014b07588 ffffffff815db3dd ffff880014b07568
 ffff880014b07610 ffff88003b868930 ffff88003b868908 ffff88003b868930
Call Trace:
 [<ffffffff815df0bb>] dump_stack+0x4e/0x68
 [<ffffffff815db3dd>] print_circular_bug+0x1fb/0x20c
 [<ffffffff810a7a3e>] __lock_acquire+0x163e/0x1d00
 [<ffffffff815e89dc>] ? retint_restore_args+0xe/0xe
 [<ffffffff815ddc7b>] ? __slab_alloc+0x4a8/0x4ce
 [<ffffffff81285fff>] ? __ext4_es_shrink+0x4f/0x2e0
 [<ffffffff810a8707>] lock_acquire+0x87/0x120
 [<ffffffff81285fff>] ? __ext4_es_shrink+0x4f/0x2e0
 [<ffffffff8128592d>] ? ext4_es_free_extent+0x5d/0x70
 [<ffffffff815e6f09>] _raw_spin_lock+0x39/0x50
 [<ffffffff81285fff>] ? __ext4_es_shrink+0x4f/0x2e0
 [<ffffffff8119760b>] ? kmem_cache_alloc+0x18b/0x1a0
 [<ffffffff81285fff>] __ext4_es_shrink+0x4f/0x2e0
 [<ffffffff812869b8>] ext4_es_insert_extent+0xc8/0x180
 [<ffffffff812470f4>] ext4_map_blocks+0x1c4/0x550
 [<ffffffff8124c4c4>] ext4_writepages+0x6d4/0xd00
	...
Reported-by: NMinchan Kim <minchan@kernel.org>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>
Reported-by: NMinchan Kim <minchan@kernel.org>
Cc: stable@vger.kernel.org
Cc: Zheng Liu <gnehzuil.liu@gmail.com>

Commit 00764937 ("ext4: initialize multi-block allocator before
checking block descriptors") causes the block group descriptor's count
of the number of free blocks to become inconsistent with the number of
free blocks in the allocation bitmap.  This is a harmless form of fs
corruption, but it causes the kernel to potentially remount the file
system read-only, or to panic, depending on the file systems's error
behavior.

Thanks to Eric Whitney for his tireless work to reproduce and to find
the guilty commit.

Fixes: 00764937 ("ext4: initialize multi-block allocator before checking block descriptors"

Cc: stable@vger.kernel.org  # 3.15
Reported-by: NDavid Jander <david@protonic.nl>
Reported-by: NMatteo Croce <technoboy85@gmail.com>
Tested-by: NEric Whitney <enwlinux@gmail.com>
Suggested-by: NEric Whitney <enwlinux@gmail.com>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>

Make ->rename2() universal, i.e. able to handle zero flags.  This is to
make future change of the API easier.
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=75861

Denis 2014-05-10 11:28:59 UTC reported:
"F2FS-fs (mmcblk0p28): mounting..
 Unable to handle kernel NULL pointer dereference at virtual address 00000018
 ...
 [<c0a2f678>] (_raw_spin_lock+0x3c/0x70) from [<c03a0330>] (issue_flush_thread+0x50/0x17c)
 [<c03a0330>] (issue_flush_thread+0x50/0x17c) from [<c01b4064>] (kthread+0x98/0xa4)
 [<c01b4064>] (kthread+0x98/0xa4) from [<c0108060>] (kernel_thread_exit+0x0/0x8)"

This patch assign cmd_control_info in sm_info before issue_flush_thread is being
created, so this make sure that issue flush thread will have no chance to access
invalid info in fcc.
Signed-off-by: NChao Yu <chao2.yu@samsung.com>
Reviewed-by: NGu Zheng <guz.fnst@cn.fujitsu.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

If we don't check the current backing device status, balance_dirty_pages can
fall into infinite pausing routine.

This can be occurred when a lot of directories make a small number of dirty
dentry pages including files.
Reported-by: NBrian Chadwick <brianchad@westnet.com.au>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

If an inode is renamed, it should be registered as file_lost_pino to conduct
checkpoint at f2fs_sync_file.
Otherwise, the inode cannot be recovered due to no dent_mark in the following
scenario.

Note that, this scenario is from xfstests/322.

1. create "a"
2. fsync "a"
3. rename "a" to "b"
4. fsync "b"
5. Sudden power-cut

After recovery is done, "b" should be seen.
However, the result shows "a", since the recovery procedure does not enter
recover_dentry due to no dent_mark.

The reason is like below.
- The nid of "a" is checkpointed during #2, f2fs_sync_file.
- The inode page for "b" produced by #3 is written without dent_mark by
sync_node_pages.

So, this patch fixes this bug by assinging file_lost_pino to the "a"'s inode.
If the pino is lost, f2fs_sync_file conducts checkpoint, and then recovers
the latest pino and its dentry information for further recovery.
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

This patch correct releasing code of new_page to avoid BUG_ON in error patch of
f2fs_rename.
Signed-off-by: NChao Yu <chao2.yu@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

If we fail in this path:
->init_inode_metadata
  ->make_empty_dir
    ->get_new_data_page
      ->grab_cache_page return -ENOMEM

We will bug on in error path of init_inode_metadata when call remove_inode_page
because i_block = 2 (one inode block will be released later & one dentry block).

We should release the dentry block in init_inode_metadata to avoid this BUG_ON,
and avoid leak of dentry block resource, because we never have second chance to
release that block in ->evict_inode as in upper error path we make this inode
'bad'.
Signed-off-by: NChao Yu <chao2.yu@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

This patch add lower bound verification for nid in check_nid_range, so nids
reserved like 0, node, meta passed by caller could be checked there.

And then check_nid_range could be used in f2fs_nfs_get_inode for simplifying
code.
Signed-off-by: NChao Yu <chao2.yu@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

Remove unused variables in struct f2fs_sm_info.
Signed-off-by: NChao Yu <chao2.yu@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

Introduced by commit 561f0ed4 (nfsd4: allow large readdirs).
Signed-off-by: NKinglong Mee <kinglongmee@gmail.com>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

As reported by Richard Sharpe, an attempt to use fuse_notify_inval_entry()
triggers complains about scheduling while atomic:

  BUG: scheduling while atomic: fuse.hf/13976/0x10000001

This happens because fuse_notify_inval_entry() attempts to allocate memory
with GFP_KERNEL, holding "struct fuse_copy_state" mapped by kmap_atomic().

Introduced by commit 58bda1da "fuse/dev: use atomic maps"

Fix by moving the map/unmap to just cover the actual memcpy operation.

Original patch from Maxim Patlasov <mpatlasov@parallels.com>
Reported-by: NRichard Sharpe <realrichardsharpe@gmail.com>
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>
Cc: <stable@vger.kernel.org> # v3.15+

If the number in "user_id=N" or "group_id=N" mount options was larger than
INT_MAX then fuse returned EINVAL.

Fix this to handle all valid uid/gid values.
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>
Cc: stable@vger.kernel.org

This patch removes the cast on data of type void * as it is not needed.
The following Coccinelle semantic patch was used for making the change:

@r@
expression x;
void* e;
type T;
identifier f;
@@

(
  *((T *)e)
|
  ((T *)x)[...]
|
  ((T *)x)->f
|
- (T *)
  e
)
Signed-off-by: NHimangi Saraogi <himangi774@gmail.com>
Acked-by: NJulia Lawall <julia.lawall@lip6.fr>
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>

The following test case demonstrates the bug:

  sh# mount -t glusterfs localhost:meta-test /mnt/one

  sh# mount -t glusterfs localhost:meta-test /mnt/two

  sh# echo stuff > /mnt/one/file; rm -f /mnt/two/file; echo stuff > /mnt/one/file
  bash: /mnt/one/file: Stale file handle

  sh# echo stuff > /mnt/one/file; rm -f /mnt/two/file; sleep 1; echo stuff > /mnt/one/file

On the second open() on /mnt/one, FUSE would have used the old
nodeid (file handle) trying to re-open it. Gluster is returning
-ESTALE. The ESTALE propagates back to namei.c:filename_lookup()
where lookup is re-attempted with LOOKUP_REVAL. The right
behavior now, would be for FUSE to ignore the entry-timeout and
and do the up-call revalidation. Instead FUSE is ignoring
LOOKUP_REVAL, succeeding the revalidation (because entry-timeout
has not passed), and open() is again retried on the old file
handle and finally the ESTALE is going back to the application.

Fix: if revalidation is happening with LOOKUP_REVAL, then ignore
entry-timeout and always do the up-call.
Signed-off-by: NAnand Avati <avati@redhat.com>
Reviewed-by: NNiels de Vos <ndevos@redhat.com>
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>
Cc: stable@vger.kernel.org

As suggested by checkpatch.pl, use time_before64() instead of direct
comparison of jiffies64 values.
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>
Cc: <stable@vger.kernel.org>

The mount manpage says of the max_batch_time option,

	This optimization can be turned off entirely
	by setting max_batch_time to 0.

But the code doesn't do that.  So fix the code to do
that.
Signed-off-by: NEric Sandeen <sandeen@redhat.com>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>
Cc: stable@vger.kernel.org

We are spending a lot of time explaining to users what this error
means.  Let's try to improve the message to avoid this problem.
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>
Cc: stable@vger.kernel.org

Make it clear that values printed are times, and that it is error
since last fsck. Also add note about fsck version required.
Signed-off-by: NPavel Machek <pavel@ucw.cz>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>
Reviewed-by: NAndreas Dilger <adilger@dilger.ca>
Cc: stable@vger.kernel.org

The first time that we allocate from an uninitialized inode allocation
bitmap, if the block allocation bitmap is also uninitalized, we need
to get write access to the block group descriptor before we start
modifying the block group descriptor flags and updating the free block
count, etc.  Otherwise, there is the potential of a bad journal
checksum (if journal checksums are enabled), and of the file system
becoming inconsistent if we crash at exactly the wrong time.
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>
Cc: stable@vger.kernel.org

There are a couple of seq_files which use the single_open() interface.
This interface requires that the whole output must fit into a single
buffer.

E.g.  for /proc/stat allocation failures have been observed because an
order-4 memory allocation failed due to memory fragmentation.  In such
situations reading /proc/stat is not possible anymore.

Therefore change the seq_file code to fallback to vmalloc allocations
which will usually result in a couple of order-0 allocations and hence
also work if memory is fragmented.

For reference a call trace where reading from /proc/stat failed:

  sadc: page allocation failure: order:4, mode:0x1040d0
  CPU: 1 PID: 192063 Comm: sadc Not tainted 3.10.0-123.el7.s390x #1
  [...]
  Call Trace:
    show_stack+0x6c/0xe8
    warn_alloc_failed+0xd6/0x138
    __alloc_pages_nodemask+0x9da/0xb68
    __get_free_pages+0x2e/0x58
    kmalloc_order_trace+0x44/0xc0
    stat_open+0x5a/0xd8
    proc_reg_open+0x8a/0x140
    do_dentry_open+0x1bc/0x2c8
    finish_open+0x46/0x60
    do_last+0x382/0x10d0
    path_openat+0xc8/0x4f8
    do_filp_open+0x46/0xa8
    do_sys_open+0x114/0x1f0
    sysc_tracego+0x14/0x1a
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Tested-by: NDavid Rientjes <rientjes@google.com>
Cc: Ian Kent <raven@themaw.net>
Cc: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Cc: Thorsten Diehl <thorsten.diehl@de.ibm.com>
Cc: Andrea Righi <andrea@betterlinux.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Stefan Bader <stefan.bader@canonical.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

These two patches are supposed to "fix" failed order-4 memory
allocations which have been observed when reading /proc/stat.  The
problem has been observed on s390 as well as on x86.

To address the problem change the seq_file memory allocations to
fallback to use vmalloc, so that allocations also work if memory is
fragmented.

This approach seems to be simpler and less intrusive than changing
/proc/stat to use an interator.  Also it "fixes" other users as well,
which use seq_file's single_open() interface.

This patch (of 2):

Use seq_file's single_open_size() to preallocate a buffer that is large
enough to hold the whole output, instead of open coding it.  Also
calculate the requested size using the number of online cpus instead of
possible cpus, since the size of the output only depends on the number
of online cpus.
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Acked-by: NDavid Rientjes <rientjes@google.com>
Cc: Ian Kent <raven@themaw.net>
Cc: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Cc: Thorsten Diehl <thorsten.diehl@de.ibm.com>
Cc: Andrea Righi <andrea@betterlinux.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Stefan Bader <stefan.bader@canonical.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

On strict build environments we can see:

  fs/autofs4/inode.c: In function 'autofs4_fill_super':
  fs/autofs4/inode.c:312: error: 'pgrp' may be used uninitialized in this function
  make[2]: *** [fs/autofs4/inode.o] Error 1
  make[1]: *** [fs/autofs4] Error 2
  make: *** [fs] Error 2
  make: *** Waiting for unfinished jobs....

This is due to the use of pgrp_set being used to indicate pgrp has has
been set rather than initializing pgrp itself.
Signed-off-by: NIan Kent <raven@themaw.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Often when starting a transaction we commit the currently running transaction,
which can end up writing block group caches when the current process has its
journal_info set to NULL (and not to a transaction). This makes our assertion
at btrfs_check_data_free_space() (current_journal != NULL) fail, resulting
in a crash/hang. Therefore fix it by setting journal_info.

Two different traces of this issue follow below.

1)

    [51502.241936] BTRFS: assertion failed: current->journal_info, file: fs/btrfs/extent-tree.c, line: 3670
    [51502.242213] ------------[ cut here ]------------
    [51502.242493] kernel BUG at fs/btrfs/ctree.h:3964!
    [51502.242669] invalid opcode: 0000 [#1] SMP DEBUG_PAGEALLOC
    (...)
    [51502.244010] Call Trace:
    [51502.244010]  [<ffffffffa02bc025>] btrfs_check_data_free_space+0x395/0x3a0 [btrfs]
    [51502.244010]  [<ffffffffa02c3bdc>] btrfs_write_dirty_block_groups+0x4ac/0x640 [btrfs]
    [51502.244010]  [<ffffffffa0357a6a>] commit_cowonly_roots+0x164/0x226 [btrfs]
    [51502.244010]  [<ffffffffa02d53cd>] btrfs_commit_transaction+0x4ed/0xab0 [btrfs]
    [51502.244010]  [<ffffffff8168ec7b>] ? _raw_spin_unlock+0x2b/0x40
    [51502.244010]  [<ffffffffa02d6259>] start_transaction+0x459/0x620 [btrfs]
    [51502.244010]  [<ffffffffa02d67ab>] btrfs_start_transaction+0x1b/0x20 [btrfs]
    [51502.244010]  [<ffffffffa02d73e1>] __unlink_start_trans+0x31/0xe0 [btrfs]
    [51502.244010]  [<ffffffffa02dea67>] btrfs_unlink+0x37/0xc0 [btrfs]
    [51502.244010]  [<ffffffff811bb054>] ? do_unlinkat+0x114/0x2a0
    [51502.244010]  [<ffffffff811baebc>] vfs_unlink+0xcc/0x150
    [51502.244010]  [<ffffffff811bb1a0>] do_unlinkat+0x260/0x2a0
    [51502.244010]  [<ffffffff811a9ef4>] ? filp_close+0x64/0x90
    [51502.244010]  [<ffffffff810aaea6>] ? trace_hardirqs_on_caller+0x16/0x1e0
    [51502.244010]  [<ffffffff81349cab>] ? trace_hardirqs_on_thunk+0x3a/0x3f
    [51502.244010]  [<ffffffff811be9eb>] SyS_unlinkat+0x1b/0x40
    [51502.244010]  [<ffffffff81698452>] system_call_fastpath+0x16/0x1b
    [51502.244010] Code: 0b 55 48 89 e5 0f 0b 55 48 89 e5 0f 0b 55 89 f1 48 c7 c2 71 13 36 a0 48 89 fe 31 c0 48 c7 c7 b8 43 36 a0 48 89 e5 e8 5d b0 32 e1 <0f> 0b 0f 1f 44 00 00 55 b9 11 00 00 00 48 89 e5 41 55 49 89 f5
    [51502.244010] RIP  [<ffffffffa03575da>] assfail.constprop.88+0x1e/0x20 [btrfs]

2)

    [25405.097230] BTRFS: assertion failed: current->journal_info, file: fs/btrfs/extent-tree.c, line: 3670
    [25405.097488] ------------[ cut here ]------------
    [25405.097767] kernel BUG at fs/btrfs/ctree.h:3964!
    [25405.097940] invalid opcode: 0000 [#1] SMP DEBUG_PAGEALLOC
    (...)
    [25405.100008] Call Trace:
    [25405.100008]  [<ffffffffa02bc025>] btrfs_check_data_free_space+0x395/0x3a0 [btrfs]
    [25405.100008]  [<ffffffffa02c3bdc>] btrfs_write_dirty_block_groups+0x4ac/0x640 [btrfs]
    [25405.100008]  [<ffffffffa035755a>] commit_cowonly_roots+0x164/0x226 [btrfs]
    [25405.100008]  [<ffffffffa02d53cd>] btrfs_commit_transaction+0x4ed/0xab0 [btrfs]
    [25405.100008]  [<ffffffff8109c170>] ? bit_waitqueue+0xc0/0xc0
    [25405.100008]  [<ffffffffa02d6259>] start_transaction+0x459/0x620 [btrfs]
    [25405.100008]  [<ffffffffa02d67ab>] btrfs_start_transaction+0x1b/0x20 [btrfs]
    [25405.100008]  [<ffffffffa02e3407>] btrfs_create+0x47/0x210 [btrfs]
    [25405.100008]  [<ffffffffa02d74cc>] ? btrfs_permission+0x3c/0x80 [btrfs]
    [25405.100008]  [<ffffffff811bc63b>] vfs_create+0x9b/0x130
    [25405.100008]  [<ffffffff811bcf19>] do_last+0x849/0xe20
    [25405.100008]  [<ffffffff811b9409>] ? link_path_walk+0x79/0x820
    [25405.100008]  [<ffffffff811bd5b5>] path_openat+0xc5/0x690
    [25405.100008]  [<ffffffff810ab07d>] ? trace_hardirqs_on+0xd/0x10
    [25405.100008]  [<ffffffff811cdcd2>] ? __alloc_fd+0x32/0x1d0
    [25405.100008]  [<ffffffff811be2a3>] do_filp_open+0x43/0xa0
    [25405.100008]  [<ffffffff811cddf1>] ? __alloc_fd+0x151/0x1d0
    [25405.100008]  [<ffffffff811abcfc>] do_sys_open+0x13c/0x230
    [25405.100008]  [<ffffffff810aaea6>] ? trace_hardirqs_on_caller+0x16/0x1e0
    [25405.100008]  [<ffffffff811abe12>] SyS_open+0x22/0x30
    [25405.100008]  [<ffffffff81698452>] system_call_fastpath+0x16/0x1b
    [25405.100008] Code: 0b 55 48 89 e5 0f 0b 55 48 89 e5 0f 0b 55 89 f1 48 c7 c2 51 13 36 a0 48 89 fe 31 c0 48 c7 c7 d0 43 36 a0 48 89 e5 e8 6d b5 32 e1 <0f> 0b 0f 1f 44 00 00 55 b9 11 00 00 00 48 89 e5 41 55 49 89 f5
    [25405.100008] RIP  [<ffffffffa03570ca>] assfail.constprop.88+0x1e/0x20 [btrfs]
Signed-off-by: NFilipe David Borba Manana <fdmanana@gmail.com>
Signed-off-by: NChris Mason <clm@fb.com>