The sceanrio is:
1. create fully node blocks
2. flush node blocks
3. write inline_data for all the node blocks again
4. flush node blocks redundantly

So, this patch tries to flush inline_data when flushing node blocks.
Reviewed-by: NChao Yu <chao2.yu@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

We should consider data block allocation to trigger f2fs_balance_fs.
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

The scenario is:
1. create lots of node blocks
2. sync
3. write lots of inline_data
-> got panic due to no free space

In that case, we should flush node blocks when writing inline_data in #3,
and trigger gc as well.
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

If there are many writepages calls by multiple threads in background, we don't
need to serialize to merge all the bios, since it's background.
In such the case, it'd better to run writepages concurrently.
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

This patch removes needless condition variable.
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

get_new_segment starts from current segment position, tries to search a
free segment among its right neighbors locate in same section.

But previously our search area was set as [current segment, max segment],
which means we have to search to more bits in free_segmap bitmap for some
worse cases. So here we correct the search area to [current segment, last
segment in section] to avoid unnecessary searching.
Signed-off-by: NChao Yu <chao2.yu@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

This patch exports a new sysfs entry 'dirty_nat_ratio' to control threshold
of dirty nat entries, if current ratio exceeds configured threshold,
checkpoint will be triggered in f2fs_balance_fs_bg for flushing dirty nats.
Signed-off-by: NChao Yu <chao2.yu@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

When testing f2fs with xfstest, generic/251 is stuck for long time,
the case uses below serials to obtain fresh released space in device,
in order to prepare for following fstrim test.

1. rm -rf /mnt/dir
2. mkdir /mnt/dir/
3. cp -axT `pwd`/ /mnt/dir/
4. goto 1

During preparing step, all nat entries will be cached in nat cache,
most of them are dirty entries with invalid blkaddr, which means
nodes related to these entries have been truncated, and they could
be reused after the dirty entries been checkpointed.

However, there was no checkpoint been triggered, so nid allocators
(e.g. mkdir, creat) will run into long journey of iterating all NAT
pages, looking for free nids in alloc_nid->build_free_nids.

Here, in f2fs_balance_fs_bg we give another chance to do checkpoint
to flush nat entries for reusing them in free nid cache when dirty
entry count exceeds 10% of max count.
Signed-off-by: NChao Yu <chao2.yu@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

Operations in is_merged_page is related to inner bio cache, move it to
data.c.
Signed-off-by: NChao Yu <chao2.yu@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

Competing overwrite DIO in dioread_nolock mode will just overwrite
pointer to io_end in the inode. This may result in data corruption or
extent conversion happening from IO completion interrupt because we
don't properly set buffer_defer_completion() when unlocked DIO races
with locked DIO to unwritten extent.

Since unlocked DIO doesn't need io_end for anything, just avoid
allocating it and corrupting pointer from inode for locked DIO.
A cleaner fix would be to avoid these games with io_end pointer from the
inode but that requires more intrusive changes so we leave that for
later.

Cc: stable@vger.kernel.org
Signed-off-by: NJan Kara <jack@suse.cz>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>

ext4 can update bh->b_state non-atomically in _ext4_get_block() and
ext4_da_get_block_prep(). Usually this is fine since bh is just a
temporary storage for mapping information on stack but in some cases it
can be fully living bh attached to a page. In such case non-atomic
update of bh->b_state can race with an atomic update which then gets
lost. Usually when we are mapping bh and thus updating bh->b_state
non-atomically, nobody else touches the bh and so things work out fine
but there is one case to especially worry about: ext4_finish_bio() uses
BH_Uptodate_Lock on the first bh in the page to synchronize handling of
PageWriteback state. So when blocksize < pagesize, we can be atomically
modifying bh->b_state of a buffer that actually isn't under IO and thus
can race e.g. with delalloc trying to map that buffer. The result is
that we can mistakenly set / clear BH_Uptodate_Lock bit resulting in the
corruption of PageWriteback state or missed unlock of BH_Uptodate_Lock.

Fix the problem by always updating bh->b_state bits atomically.

CC: stable@vger.kernel.org
Reported-by: NNikolay Borisov <kernel@kyup.com>
Signed-off-by: NJan Kara <jack@suse.cz>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>

We don't require a dedicated thread for fsnotify cleanup.  Switch it
over to a workqueue job instead that runs on the system_unbound_wq.

In the interest of not thrashing the queued job too often when there are
a lot of marks being removed, we delay the reaper job slightly when
queueing it, to allow several to gather on the list.
Signed-off-by: NJeff Layton <jeff.layton@primarydata.com>
Tested-by: NEryu Guan <guaneryu@gmail.com>
Reviewed-by: NJan Kara <jack@suse.cz>
Cc: Eric Paris <eparis@parisplace.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This reverts commit c510eff6 ("fsnotify: destroy marks with
call_srcu instead of dedicated thread").

Eryu reported that he was seeing some OOM kills kick in when running a
testcase that adds and removes inotify marks on a file in a tight loop.

The above commit changed the code to use call_srcu to clean up the
marks.  While that does (in principle) work, the srcu callback job is
limited to cleaning up entries in small batches and only once per jiffy.
It's easily possible to overwhelm that machinery with too many call_srcu
callbacks, and Eryu's reproduer did just that.

There's also another potential problem with using call_srcu here.  While
you can obviously sleep while holding the srcu_read_lock, the callbacks
run under local_bh_disable, so you can't sleep there.

It's possible when putting the last reference to the fsnotify_mark that
we'll end up putting a chain of references including the fsnotify_group,
uid, and associated keys.  While I don't see any obvious ways that that
could occurs, it's probably still best to avoid using call_srcu here
after all.

This patch reverts the above patch.  A later patch will take a different
approach to eliminated the dedicated thread here.
Signed-off-by: NJeff Layton <jeff.layton@primarydata.com>
Reported-by: NEryu Guan <guaneryu@gmail.com>
Tested-by: NEryu Guan <guaneryu@gmail.com>
Cc: Jan Kara <jack@suse.com>
Cc: Eric Paris <eparis@parisplace.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

inode struct members that track cgroup writeback information
should be reinitialized when inode gets allocated from
kmem_cache. Otherwise, their values remain and get used by the
new inode.
Signed-off-by: NTahsin Erdogan <tahsin@google.com>
Acked-by: NTejun Heo <tj@kernel.org>
Fixes: d10c8095 ("writeback: implement foreign cgroup inode bdi_writeback switching")
Signed-off-by: NJens Axboe <axboe@fb.com>

If cgroup writeback is in use, an inode is associated with a cgroup
for writeback.  If the inode's main dirtier changes to another cgroup,
the association gets updated asynchronously.  Nothing was pinning the
superblock while such switches are in progress and superblock could go
away while async switching is pending or in progress leading to
crashes like the following.

 kernel BUG at fs/jbd2/transaction.c:319!
 invalid opcode: 0000 [#1] SMP DEBUG_PAGEALLOC
 CPU: 1 PID: 29158 Comm: kworker/1:10 Not tainted 4.5.0-rc3 #51
 Hardware name: Google Google, BIOS Google 01/01/2011
 Workqueue: events inode_switch_wbs_work_fn
 task: ffff880213dbbd40 ti: ffff880209264000 task.ti: ffff880209264000
 RIP: 0010:[<ffffffff803e6922>]  [<ffffffff803e6922>] start_this_handle+0x382/0x3e0
 RSP: 0018:ffff880209267c30  EFLAGS: 00010202
 ...
 Call Trace:
  [<ffffffff803e6be4>] jbd2__journal_start+0xf4/0x190
  [<ffffffff803cfc7e>] __ext4_journal_start_sb+0x4e/0x70
  [<ffffffff803b31ec>] ext4_evict_inode+0x12c/0x3d0
  [<ffffffff8035338b>] evict+0xbb/0x190
  [<ffffffff80354190>] iput+0x130/0x190
  [<ffffffff80360223>] inode_switch_wbs_work_fn+0x343/0x4c0
  [<ffffffff80279819>] process_one_work+0x129/0x300
  [<ffffffff80279b16>] worker_thread+0x126/0x480
  [<ffffffff8027ed14>] kthread+0xc4/0xe0
  [<ffffffff809771df>] ret_from_fork+0x3f/0x70

Fix it by bumping s_active while cgroup association switching is in
flight.
Signed-off-by: NTejun Heo <tj@kernel.org>
Reported-and-tested-by: NTahsin Erdogan <tahsin@google.com>
Link: http://lkml.kernel.org/g/CAAeU0aNCq7LGODvVGRU-oU_o-6enii5ey0p1c26D1ZzYwkDc5A@mail.gmail.com
Fixes: d10c8095 ("writeback: implement foreign cgroup inode bdi_writeback switching")
Cc: stable@vger.kernel.org #v4.5+
Signed-off-by: NJens Axboe <axboe@fb.com>

When ext4_bread() fails, fname_crypto_str remains
allocated after return. Fix that.
Signed-off-by: NKirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>
CC: Dmitry Monakhov <dmonakhov@virtuozzo.com>

If a bio for a direct IO request fails, we were not setting the error in
the parent bio (the main DIO bio), making us not return the error to
user space in btrfs_direct_IO(), that is, it made __blockdev_direct_IO()
return the number of bytes issued for IO and not the error a bio created
and submitted by btrfs_submit_direct() got from the block layer.
This essentially happens because when we call:

   dio_end_io(dio_bio, bio->bi_error);

It does not set dio_bio->bi_error to the value of the second argument.
So just add this missing assignment in endio callbacks, just as we do in
the error path at btrfs_submit_direct() when we fail to clone the dio bio
or allocate its private object. This follows the convention of what is
done with other similar APIs such as bio_endio() where the caller is
responsible for setting the bi_error field in the bio it passes as an
argument to bio_endio().

This was detected by the new generic test cases in xfstests: 271, 272,
276 and 278. Which essentially setup a dm error target, then load the
error table, do a direct IO write and unload the error table. They
expect the write to fail with -EIO, which was not getting reported
when testing against btrfs.

Cc: stable@vger.kernel.org  # 4.3+
Fixes: 4246a0b6 ("block: add a bi_error field to struct bio")
Signed-off-by: NFilipe Manana <fdmanana@suse.com>

The "newblock" parameter is not used in convert_initialized_extent(),
remove it.
Signed-off-by: NEryu Guan <guaneryu@gmail.com>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>

I notice ext4/307 fails occasionally on ppc64 host, reporting md5
checksum mismatch after moving data from original file to donor file.

The reason is that move_extent_per_page() calls __block_write_begin()
and block_commit_write() to write saved data from original inode blocks
to donor inode blocks, but __block_write_begin() not only maps buffer
heads but also reads block content from disk if the size is not block
size aligned.  At this time the physical block number in mapped buffer
head is pointing to the donor file not the original file, and that
results in reading wrong data to page, which get written to disk in
following block_commit_write call.

This also can be reproduced by the following script on 1k block size ext4
on x86_64 host:

    mnt=/mnt/ext4
    donorfile=$mnt/donor
    testfile=$mnt/testfile
    e4compact=~/xfstests/src/e4compact

    rm -f $donorfile $testfile

    # reserve space for donor file, written by 0xaa and sync to disk to
    # avoid EBUSY on EXT4_IOC_MOVE_EXT
    xfs_io -fc "pwrite -S 0xaa 0 1m" -c "fsync" $donorfile

    # create test file written by 0xbb
    xfs_io -fc "pwrite -S 0xbb 0 1023" -c "fsync" $testfile

    # compute initial md5sum
    md5sum $testfile | tee md5sum.txt
    # drop cache, force e4compact to read data from disk
    echo 3 > /proc/sys/vm/drop_caches

    # test defrag
    echo "$testfile" | $e4compact -i -v -f $donorfile
    # check md5sum
    md5sum -c md5sum.txt

Fix it by creating & mapping buffer heads only but not reading blocks
from disk, because all the data in page is guaranteed to be up-to-date
in mext_page_mkuptodate().

Cc: stable@vger.kernel.org
Signed-off-by: NEryu Guan <guaneryu@gmail.com>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>

Since sizeof(ext_new_group_data) > sizeof(ext_new_flex_group_data),
integer overflow could be happened.
Therefore, need to fix integer overflow sanitization.

Cc: stable@vger.kernel.org
Signed-off-by: NInsu Yun <wuninsu@gmail.com>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>

This patch adds a line break for proc mb_groups display.
Signed-off-by: NHuaitong Han <huaitong.han@intel.com>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>
Reviewed-by: NAndreas Dilger <adilger@dilger.ca>

The ext4_ioctl_setflags() function which is used in the ioctls
EXT4_IOC_SETFLAGS and EXT4_IOC_FSSETXATTR may return the positive value
EPERM instead of -EPERM in case of error. This bug was introduced by a
recent commit 9b7365fc.

The following program can be used to illustrate the wrong behavior:

    #include <sys/types.h>
    #include <sys/ioctl.h>
    #include <sys/stat.h>
    #include <fcntl.h>
    #include <err.h>

    #define FS_IOC_GETFLAGS _IOR('f', 1, long)
    #define FS_IOC_SETFLAGS _IOW('f', 2, long)
    #define FS_IMMUTABLE_FL 0x00000010

    int main(void)
    {
        int fd;
        long flags;

        fd = open("file", O_RDWR|O_CREAT, 0600);
        if (fd < 0)
            err(1, "open");

        if (ioctl(fd, FS_IOC_GETFLAGS, &flags) < 0)
            err(1, "ioctl: FS_IOC_GETFLAGS");

        flags |= FS_IMMUTABLE_FL;

        if (ioctl(fd, FS_IOC_SETFLAGS, &flags) < 0)
            err(1, "ioctl: FS_IOC_SETFLAGS");

        warnx("ioctl returned no error");

        return 0;
    }

Running it gives the following result:

    $ strace -e ioctl ./test
    ioctl(3, FS_IOC_GETFLAGS, 0x7ffdbd8bfd38) = 0
    ioctl(3, FS_IOC_SETFLAGS, 0x7ffdbd8bfd38) = 1
    test: ioctl returned no error
    +++ exited with 0 +++

Running the program on a kernel with the bug fixed gives the proper result:

    $ strace -e ioctl ./test
    ioctl(3, FS_IOC_GETFLAGS, 0x7ffdd2768258) = 0
    ioctl(3, FS_IOC_SETFLAGS, 0x7ffdd2768258) = -1 EPERM (Operation not permitted)
    test: ioctl: FS_IOC_SETFLAGS: Operation not permitted
    +++ exited with 1 +++
Signed-off-by: NAnton Protopopov <a.s.protopopov@gmail.com>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>

When block group checksum is wrong, we call ext4_error() while holding
group spinlock from ext4_init_block_bitmap() or
ext4_init_inode_bitmap() which results in scheduling while in atomic.
Fix the issue by calling ext4_error() later after dropping the spinlock.

CC: stable@vger.kernel.org
Reported-by: NDmitry Vyukov <dvyukov@google.com>
Signed-off-by: NJan Kara <jack@suse.cz>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>
Reviewed-by: NDarrick J. Wong <darrick.wong@oracle.com>

The value of ctx->pos in the last readdir call is supposed to be set to
INT_MAX due to 32bit compatibility, unless 'pos' is intentially set to a
larger value, then it's LLONG_MAX.

There's a report from PaX SIZE_OVERFLOW plugin that "ctx->pos++"
overflows (https://forums.grsecurity.net/viewtopic.php?f=1&t=4284), on a
64bit arch, where the value is 0x7fffffffffffffff ie. LLONG_MAX before
the increment.

We can get to that situation like that:

* emit all regular readdir entries
* still in the same call to readdir, bump the last pos to INT_MAX
* next call to readdir will not emit any entries, but will reach the
  bump code again, finds pos to be INT_MAX and sets it to LLONG_MAX

Normally this is not a problem, but if we call readdir again, we'll find
'pos' set to LLONG_MAX and the unconditional increment will overflow.

The report from Victor at
(http://thread.gmane.org/gmane.comp.file-systems.btrfs/49500) with debugging
print shows that pattern:

 Overflow: e
 Overflow: 7fffffff
 Overflow: 7fffffffffffffff
 PAX: size overflow detected in function btrfs_real_readdir
   fs/btrfs/inode.c:5760 cicus.935_282 max, count: 9, decl: pos; num: 0;
   context: dir_context;
 CPU: 0 PID: 2630 Comm: polkitd Not tainted 4.2.3-grsec #1
 Hardware name: Gigabyte Technology Co., Ltd. H81ND2H/H81ND2H, BIOS F3 08/11/2015
  ffffffff81901608 0000000000000000 ffffffff819015e6 ffffc90004973d48
  ffffffff81742f0f 0000000000000007 ffffffff81901608 ffffc90004973d78
  ffffffff811cb706 0000000000000000 ffff8800d47359e0 ffffc90004973ed8
 Call Trace:
  [<ffffffff81742f0f>] dump_stack+0x4c/0x7f
  [<ffffffff811cb706>] report_size_overflow+0x36/0x40
  [<ffffffff812ef0bc>] btrfs_real_readdir+0x69c/0x6d0
  [<ffffffff811dafc8>] iterate_dir+0xa8/0x150
  [<ffffffff811e6d8d>] ? __fget_light+0x2d/0x70
  [<ffffffff811dba3a>] SyS_getdents+0xba/0x1c0
 Overflow: 1a
  [<ffffffff811db070>] ? iterate_dir+0x150/0x150
  [<ffffffff81749b69>] entry_SYSCALL_64_fastpath+0x12/0x83

The jump from 7fffffff to 7fffffffffffffff happens when new dir entries
are not yet synced and are processed from the delayed list. Then the code
could go to the bump section again even though it might not emit any new
dir entries from the delayed list.

The fix avoids entering the "bump" section again once we've finished
emitting the entries, both for synced and delayed entries.

References: https://forums.grsecurity.net/viewtopic.php?f=1&t=4284Reported-by: NVictor <services@swwu.com>
CC: stable@vger.kernel.org
Signed-off-by: NDavid Sterba <dsterba@suse.com>
Tested-by: NHolger Hoffstätte <holger.hoffstaette@googlemail.com>
Signed-off-by: NChris Mason <clm@fb.com>

The setup_ntlmv2_rsp() function may return positive value ENOMEM instead
of -ENOMEM in case of kmalloc failure.
Signed-off-by: NAnton Protopopov <a.s.protopopov@gmail.com>
CC: Stable <stable@vger.kernel.org>
Signed-off-by: NSteve French <smfrench@gmail.com>

In worst case, "ip=" + sb_mountdata + ipv6 can be copied into mountdata.
Therefore, for safe, it is better to add more size when allocating memory.
Signed-off-by: NInsu Yun <wuninsu@gmail.com>
Signed-off-by: NSteve French <smfrench@gmail.com>

server_RFC1001_name is declared as a RFC1001_NAME_LEN_WITH_NULL sized
char array in struct TCP_Server_Info so the null pointer check on
server_RFC1001_name is redundant and can be removed.  Detected with
smatch:

fs/cifs/connect.c:2982 ip_rfc1001_connect() warn: this array is probably
  non-NULL. 'server->server_RFC1001_name'
Signed-off-by: NColin Ian King <colin.king@canonical.com>
Signed-off-by: NSteve French <smfrench@gmail.com>

"rm -rf" is bricking some peoples' laptops because of variables being
used to store non-reinitializable firmware driver data that's required
to POST the hardware.

These are 100% bugs, and they need to be fixed, but in the mean time it
shouldn't be easy to *accidentally* brick machines.

We have to have delete working, and picking which variables do and don't
work for deletion is quite intractable, so instead make everything
immutable by default (except for a whitelist), and make tools that
aren't quite so broad-spectrum unset the immutable flag.
Signed-off-by: NPeter Jones <pjones@redhat.com>
Tested-by: NLee, Chun-Yi <jlee@suse.com>
Acked-by: NMatthew Garrett <mjg59@coreos.com>
Signed-off-by: NMatt Fleming <matt@codeblueprint.co.uk>

Translate EFI's UCS-2 variable names to UTF-8 instead of just assuming
all variable names fit in ASCII.
Signed-off-by: NPeter Jones <pjones@redhat.com>
Acked-by: NMatthew Garrett <mjg59@coreos.com>
Tested-by: NLee, Chun-Yi <jlee@suse.com>
Signed-off-by: NMatt Fleming <matt@codeblueprint.co.uk>

In the case where the per-file key for the directory is cached, but
root does not have access to the key needed to derive the per-file key
for the files in the directory, we allow the lookup to succeed, so
that lstat(2) and unlink(2) can suceed.  However, if a program tries
to open the file, it will get an ENOKEY error.
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>

Add a validation check for dentries for encrypted directory to make
sure we're not caching stale data after a key has been added or removed.

Also check to make sure that status of the encryption key is updated
when readdir(2) is executed.
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>

Since the checksum function and the field are both __le32, don't
perform endian conversion when comparing the two.  This fixes mount
failures on ppc64.
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: NBrian Foster <bfoster@redhat.com>
Signed-off-by: NDave Chinner <david@fromorbit.com>

Considering current pty code and multiple devpts instances, it's possible
to umount a devpts file system while a program still has /dev/tty opened
pointing to a previosuly closed pty pair in that instance. In the case all
ptmx and pts/N files are closed, umount can be done. If the program closes
/dev/tty after umount is done, devpts_kill_index will use now an invalid
super_block, which was already destroyed in the umount operation after
running ->kill_sb. This is another "use after free" type of issue, but now
related to the allocated super_block instance.

To avoid the problem (warning at ida_remove and potential crashes) for
this specific case, I added two functions in devpts which grabs additional
references to the super_block, which pty code now uses so it makes sure
the super block structure is still valid until pty shutdown is done.
I also moved the additional inode references to the same functions, which
also covered similar case with inode being freed before /dev/tty final
close/shutdown.
Signed-off-by: NHerton R. Krzesinski <herton@redhat.com>
Cc: stable@vger.kernel.org # 2.6.29+
Reviewed-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

In the current implementation of the EPOLLEXCLUSIVE flag (added for
4.5-rc1), if epoll waiters create different POLL* sets and register them
as exclusive against the same target fd, the current implementation will
stop waking any further waiters once it finds the first idle waiter.
This means that waiters could miss wakeups in certain cases.

For example, when we wake up a pipe for reading we do:
wake_up_interruptible_sync_poll(&pipe->wait, POLLIN | POLLRDNORM); So if
one epoll set or epfd is added to pipe p with POLLIN and a second set
epfd2 is added to pipe p with POLLRDNORM, only epfd may receive the
wakeup since the current implementation will stop after it finds any
intersection of events with a waiter that is blocked in epoll_wait().

We could potentially address this by requiring all epoll waiters that
are added to p be required to pass the same set of POLL* events.  IE the
first EPOLL_CTL_ADD that passes EPOLLEXCLUSIVE establishes the set POLL*
flags to be used by any other epfds that are added as EPOLLEXCLUSIVE.
However, I think it might be somewhat confusing interface as we would
have to reference count the number of users for that set, and so
userspace would have to keep track of that count, or we would need a
more involved interface.  It also adds some shared state that we'd have
store somewhere.  I don't think anybody will want to bloat
__wait_queue_head for this.

I think what we could do instead, is to simply restrict EPOLLEXCLUSIVE
such that it can only be specified with EPOLLIN and/or EPOLLOUT.  So
that way if the wakeup includes 'POLLIN' and not 'POLLOUT', we can stop
once we hit the first idle waiter that specifies the EPOLLIN bit, since
any remaining waiters that only have 'POLLOUT' set wouldn't need to be
woken.  Likewise, we can do the same thing if 'POLLOUT' is in the wakeup
bit set and not 'POLLIN'.  If both 'POLLOUT' and 'POLLIN' are set in the
wake bit set (there is at least one example of this I saw in fs/pipe.c),
then we just wake the entire exclusive list.  Having both 'POLLOUT' and
'POLLIN' both set should not be on any performance critical path, so I
think that's ok (in fs/pipe.c its in pipe_release()).  We also continue
to include EPOLLERR and EPOLLHUP by default in any exclusive set.  Thus,
the user can specify EPOLLERR and/or EPOLLHUP but is not required to do
so.

Since epoll waiters may be interested in other events as well besides
EPOLLIN, EPOLLOUT, EPOLLERR and EPOLLHUP, these can still be added by
doing a 'dup' call on the target fd and adding that as one normally
would with EPOLL_CTL_ADD.  Since I think that the POLLIN and POLLOUT
events are what we are interest in balancing, I think that the 'dup'
thing could perhaps be added to only one of the waiter threads.
However, I think that EPOLLIN, EPOLLOUT, EPOLLERR and EPOLLHUP should be
sufficient for the majority of use-cases.

Since EPOLLEXCLUSIVE is intended to be used with a target fd shared
among multiple epfds, where between 1 and n of the epfds may receive an
event, it does not satisfy the semantics of EPOLLONESHOT where only 1
epfd would get an event.  Thus, it is not allowed to be specified in
conjunction with EPOLLEXCLUSIVE.

EPOLL_CTL_MOD is also not allowed if the fd was previously added as
EPOLLEXCLUSIVE.  It seems with the limited number of flags to not be as
interesting, but this could be relaxed at some further point.
Signed-off-by: NJason Baron <jbaron@akamai.com>
Tested-by: NMadars Vitolins <m@silodev.com>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Al Viro <viro@ftp.linux.org.uk>
Cc: Eric Wong <normalperson@yhbt.net>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Hagen Paul Pfeifer <hagen@jauu.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NDmitry Monakhov <dmonakhov@openvz.org>
Reviewed-by: NJan Kara <jack@suse.cz>
Reviewed-by: NRoss Zwisler <ross.zwisler@linux.intel.com>
Cc: Matthew Wilcox <matthew.r.wilcox@intel.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

When recovery master down, dlm_do_local_recovery_cleanup() only remove
the $RECOVERY lock owned by dead node, but do not clear the refmap bit.
Which will make umount thread falling in dead loop migrating $RECOVERY
to the dead node.
Signed-off-by: Nxuejiufei <xuejiufei@huawei.com>
Reviewed-by: NJoseph Qi <joseph.qi@huawei.com>
Cc: Mark Fasheh <mfasheh@suse.de>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Previously the pfn_mkwrite() fault handler for raw block devices called
bldev_dax_fault() -> __dax_fault() to do a full DAX page fault.

Really what the pfn_mkwrite() fault handler needs to do is call
dax_pfn_mkwrite() to make sure that the radix tree entry for the given
PTE is marked as dirty so that a follow-up fsync or msync call will
flush it durably to media.

Fixes: 5a023cdb ("block: enable dax for raw block devices")
Signed-off-by: NRoss Zwisler <ross.zwisler@linux.intel.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Chinner <david@fromorbit.com>
Reviewed-by: NJan Kara <jack@suse.cz>
Cc: Matthew Wilcox <willy@linux.intel.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

While doing some tests I ran into an hang on an extent buffer's rwlock
that produced the following trace:

[39389.800012] NMI watchdog: BUG: soft lockup - CPU#15 stuck for 22s! [fdm-stress:32166]
[39389.800016] NMI watchdog: BUG: soft lockup - CPU#14 stuck for 22s! [fdm-stress:32165]
[39389.800016] Modules linked in: btrfs dm_mod ppdev xor sha256_generic hmac raid6_pq drbg ansi_cprng aesni_intel i2c_piix4 acpi_cpufreq aes_x86_64 ablk_helper tpm_tis parport_pc i2c_core sg cryptd evdev psmouse lrw tpm parport gf128mul serio_raw pcspkr glue_helper processor button loop autofs4 ext4 crc16 mbcache jbd2 sd_mod sr_mod cdrom ata_generic virtio_scsi ata_piix libata virtio_pci virtio_ring crc32c_intel scsi_mod e1000 virtio floppy [last unloaded: btrfs]
[39389.800016] irq event stamp: 0
[39389.800016] hardirqs last  enabled at (0): [<          (null)>]           (null)
[39389.800016] hardirqs last disabled at (0): [<ffffffff8104e58d>] copy_process+0x638/0x1a35
[39389.800016] softirqs last  enabled at (0): [<ffffffff8104e58d>] copy_process+0x638/0x1a35
[39389.800016] softirqs last disabled at (0): [<          (null)>]           (null)
[39389.800016] CPU: 14 PID: 32165 Comm: fdm-stress Not tainted 4.4.0-rc6-btrfs-next-18+ #1
[39389.800016] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS by qemu-project.org 04/01/2014
[39389.800016] task: ffff880175b1ca40 ti: ffff8800a185c000 task.ti: ffff8800a185c000
[39389.800016] RIP: 0010:[<ffffffff810902af>]  [<ffffffff810902af>] queued_spin_lock_slowpath+0x57/0x158
[39389.800016] RSP: 0018:ffff8800a185fb80  EFLAGS: 00000202
[39389.800016] RAX: 0000000000000101 RBX: ffff8801710c4e9c RCX: 0000000000000101
[39389.800016] RDX: 0000000000000100 RSI: 0000000000000001 RDI: 0000000000000001
[39389.800016] RBP: ffff8800a185fb98 R08: 0000000000000001 R09: 0000000000000000
[39389.800016] R10: ffff8800a185fb68 R11: 6db6db6db6db6db7 R12: ffff8801710c4e98
[39389.800016] R13: ffff880175b1ca40 R14: ffff8800a185fc10 R15: ffff880175b1ca40
[39389.800016] FS:  00007f6d37fff700(0000) GS:ffff8802be9c0000(0000) knlGS:0000000000000000
[39389.800016] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[39389.800016] CR2: 00007f6d300019b8 CR3: 0000000037c93000 CR4: 00000000001406e0
[39389.800016] Stack:
[39389.800016]  ffff8801710c4e98 ffff8801710c4e98 ffff880175b1ca40 ffff8800a185fbb0
[39389.800016]  ffffffff81091e11 ffff8801710c4e98 ffff8800a185fbc8 ffffffff81091895
[39389.800016]  ffff8801710c4e98 ffff8800a185fbe8 ffffffff81486c5c ffffffffa067288c
[39389.800016] Call Trace:
[39389.800016]  [<ffffffff81091e11>] queued_read_lock_slowpath+0x46/0x60
[39389.800016]  [<ffffffff81091895>] do_raw_read_lock+0x3e/0x41
[39389.800016]  [<ffffffff81486c5c>] _raw_read_lock+0x3d/0x44
[39389.800016]  [<ffffffffa067288c>] ? btrfs_tree_read_lock+0x54/0x125 [btrfs]
[39389.800016]  [<ffffffffa067288c>] btrfs_tree_read_lock+0x54/0x125 [btrfs]
[39389.800016]  [<ffffffffa0622ced>] ? btrfs_find_item+0xa7/0xd2 [btrfs]
[39389.800016]  [<ffffffffa069363f>] btrfs_ref_to_path+0xd6/0x174 [btrfs]
[39389.800016]  [<ffffffffa0693730>] inode_to_path+0x53/0xa2 [btrfs]
[39389.800016]  [<ffffffffa0693e2e>] paths_from_inode+0x117/0x2ec [btrfs]
[39389.800016]  [<ffffffffa0670cff>] btrfs_ioctl+0xd5b/0x2793 [btrfs]
[39389.800016]  [<ffffffff8108a8b0>] ? arch_local_irq_save+0x9/0xc
[39389.800016]  [<ffffffff81276727>] ? __this_cpu_preempt_check+0x13/0x15
[39389.800016]  [<ffffffff8108a8b0>] ? arch_local_irq_save+0x9/0xc
[39389.800016]  [<ffffffff8118b3d4>] ? rcu_read_unlock+0x3e/0x5d
[39389.800016]  [<ffffffff811822f8>] do_vfs_ioctl+0x42b/0x4ea
[39389.800016]  [<ffffffff8118b4f3>] ? __fget_light+0x62/0x71
[39389.800016]  [<ffffffff8118240e>] SyS_ioctl+0x57/0x79
[39389.800016]  [<ffffffff814872d7>] entry_SYSCALL_64_fastpath+0x12/0x6f
[39389.800016] Code: b9 01 01 00 00 f7 c6 00 ff ff ff 75 32 83 fe 01 89 ca 89 f0 0f 45 d7 f0 0f b1 13 39 f0 74 04 89 c6 eb e2 ff ca 0f 84 fa 00 00 00 <8b> 03 84 c0 74 04 f3 90 eb f6 66 c7 03 01 00 e9 e6 00 00 00 e8
[39389.800012] Modules linked in: btrfs dm_mod ppdev xor sha256_generic hmac raid6_pq drbg ansi_cprng aesni_intel i2c_piix4 acpi_cpufreq aes_x86_64 ablk_helper tpm_tis parport_pc i2c_core sg cryptd evdev psmouse lrw tpm parport gf128mul serio_raw pcspkr glue_helper processor button loop autofs4 ext4 crc16 mbcache jbd2 sd_mod sr_mod cdrom ata_generic virtio_scsi ata_piix libata virtio_pci virtio_ring crc32c_intel scsi_mod e1000 virtio floppy [last unloaded: btrfs]
[39389.800012] irq event stamp: 0
[39389.800012] hardirqs last  enabled at (0): [<          (null)>]           (null)
[39389.800012] hardirqs last disabled at (0): [<ffffffff8104e58d>] copy_process+0x638/0x1a35
[39389.800012] softirqs last  enabled at (0): [<ffffffff8104e58d>] copy_process+0x638/0x1a35
[39389.800012] softirqs last disabled at (0): [<          (null)>]           (null)
[39389.800012] CPU: 15 PID: 32166 Comm: fdm-stress Tainted: G             L  4.4.0-rc6-btrfs-next-18+ #1
[39389.800012] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS by qemu-project.org 04/01/2014
[39389.800012] task: ffff880179294380 ti: ffff880034a60000 task.ti: ffff880034a60000
[39389.800012] RIP: 0010:[<ffffffff81091e8d>]  [<ffffffff81091e8d>] queued_write_lock_slowpath+0x62/0x72
[39389.800012] RSP: 0018:ffff880034a639f0  EFLAGS: 00000206
[39389.800012] RAX: 0000000000000101 RBX: ffff8801710c4e98 RCX: 0000000000000000
[39389.800012] RDX: 00000000000000ff RSI: 0000000000000000 RDI: ffff8801710c4e9c
[39389.800012] RBP: ffff880034a639f8 R08: 0000000000000001 R09: 0000000000000000
[39389.800012] R10: ffff880034a639b0 R11: 0000000000001000 R12: ffff8801710c4e98
[39389.800012] R13: 0000000000000001 R14: ffff880172cbc000 R15: ffff8801710c4e00
[39389.800012] FS:  00007f6d377fe700(0000) GS:ffff8802be9e0000(0000) knlGS:0000000000000000
[39389.800012] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[39389.800012] CR2: 00007f6d3d3c1000 CR3: 0000000037c93000 CR4: 00000000001406e0
[39389.800012] Stack:
[39389.800012]  ffff8801710c4e98 ffff880034a63a10 ffffffff81091963 ffff8801710c4e98
[39389.800012]  ffff880034a63a30 ffffffff81486f1b ffffffffa0672cb3 ffff8801710c4e00
[39389.800012]  ffff880034a63a78 ffffffffa0672cb3 ffff8801710c4e00 ffff880034a63a58
[39389.800012] Call Trace:
[39389.800012]  [<ffffffff81091963>] do_raw_write_lock+0x72/0x8c
[39389.800012]  [<ffffffff81486f1b>] _raw_write_lock+0x3a/0x41
[39389.800012]  [<ffffffffa0672cb3>] ? btrfs_tree_lock+0x119/0x251 [btrfs]
[39389.800012]  [<ffffffffa0672cb3>] btrfs_tree_lock+0x119/0x251 [btrfs]
[39389.800012]  [<ffffffffa061aeba>] ? rcu_read_unlock+0x5b/0x5d [btrfs]
[39389.800012]  [<ffffffffa061ce13>] ? btrfs_root_node+0xda/0xe6 [btrfs]
[39389.800012]  [<ffffffffa061ce83>] btrfs_lock_root_node+0x22/0x42 [btrfs]
[39389.800012]  [<ffffffffa062046b>] btrfs_search_slot+0x1b8/0x758 [btrfs]
[39389.800012]  [<ffffffff810fc6b0>] ? time_hardirqs_on+0x15/0x28
[39389.800012]  [<ffffffffa06365db>] btrfs_lookup_inode+0x31/0x95 [btrfs]
[39389.800012]  [<ffffffff8108d62f>] ? trace_hardirqs_on+0xd/0xf
[39389.800012]  [<ffffffff8148482b>] ? mutex_lock_nested+0x397/0x3bc
[39389.800012]  [<ffffffffa068821b>] __btrfs_update_delayed_inode+0x59/0x1c0 [btrfs]
[39389.800012]  [<ffffffffa068858e>] __btrfs_commit_inode_delayed_items+0x194/0x5aa [btrfs]
[39389.800012]  [<ffffffff81486ab7>] ? _raw_spin_unlock+0x31/0x44
[39389.800012]  [<ffffffffa0688a48>] __btrfs_run_delayed_items+0xa4/0x15c [btrfs]
[39389.800012]  [<ffffffffa0688d62>] btrfs_run_delayed_items+0x11/0x13 [btrfs]
[39389.800012]  [<ffffffffa064048e>] btrfs_commit_transaction+0x234/0x96e [btrfs]
[39389.800012]  [<ffffffffa0618d10>] btrfs_sync_fs+0x145/0x1ad [btrfs]
[39389.800012]  [<ffffffffa0671176>] btrfs_ioctl+0x11d2/0x2793 [btrfs]
[39389.800012]  [<ffffffff8108a8b0>] ? arch_local_irq_save+0x9/0xc
[39389.800012]  [<ffffffff81140261>] ? __might_fault+0x4c/0xa7
[39389.800012]  [<ffffffff81140261>] ? __might_fault+0x4c/0xa7
[39389.800012]  [<ffffffff8108a8b0>] ? arch_local_irq_save+0x9/0xc
[39389.800012]  [<ffffffff8118b3d4>] ? rcu_read_unlock+0x3e/0x5d
[39389.800012]  [<ffffffff811822f8>] do_vfs_ioctl+0x42b/0x4ea
[39389.800012]  [<ffffffff8118b4f3>] ? __fget_light+0x62/0x71
[39389.800012]  [<ffffffff8118240e>] SyS_ioctl+0x57/0x79
[39389.800012]  [<ffffffff814872d7>] entry_SYSCALL_64_fastpath+0x12/0x6f
[39389.800012] Code: f0 0f b1 13 85 c0 75 ef eb 2a f3 90 8a 03 84 c0 75 f8 f0 0f b0 13 84 c0 75 f0 ba ff 00 00 00 eb 0a f0 0f b1 13 ff c8 74 0b f3 90 <8b> 03 83 f8 01 75 f7 eb ed c6 43 04 00 5b 5d c3 0f 1f 44 00 00

This happens because in the code path executed by the inode_paths ioctl we
end up nesting two calls to read lock a leaf's rwlock when after the first
call to read_lock() and before the second call to read_lock(), another
task (running the delayed items as part of a transaction commit) has
already called write_lock() against the leaf's rwlock. This situation is
illustrated by the following diagram:

         Task A                       Task B

  btrfs_ref_to_path()               btrfs_commit_transaction()
    read_lock(&eb->lock);

                                      btrfs_run_delayed_items()
                                        __btrfs_commit_inode_delayed_items()
                                          __btrfs_update_delayed_inode()
                                            btrfs_lookup_inode()

                                              write_lock(&eb->lock);
                                                --> task waits for lock

    read_lock(&eb->lock);
    --> makes this task hang
        forever (and task B too
	of course)

So fix this by avoiding doing the nested read lock, which is easily
avoidable. This issue does not happen if task B calls write_lock() after
task A does the second call to read_lock(), however there does not seem
to exist anything in the documentation that mentions what is the expected
behaviour for recursive locking of rwlocks (leaving the idea that doing
so is not a good usage of rwlocks).

Also, as a side effect necessary for this fix, make sure we do not
needlessly read lock extent buffers when the input path has skip_locking
set (used when called from send).

Cc: stable@vger.kernel.org
Signed-off-by: NFilipe Manana <fdmanana@suse.com>

Signed-off-by: NYan, Zheng <zyan@redhat.com>

ceph_osdc_alloc_request() returns NULL on error, it never returns error
pointers.

Fixes: 5be0389d ('ceph: re-send AIO write request when getting -EOLDSNAP error')
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NIlya Dryomov <idryomov@gmail.com>