While creating a block group, we often end up getting ENOSPC while updating
the chunk tree, which leads to a transaction abortion that produces a trace
like the following:

[30670.116368] WARNING: CPU: 4 PID: 20735 at fs/btrfs/super.c:260 __btrfs_abort_transaction+0x52/0x106 [btrfs]()
[30670.117777] BTRFS: Transaction aborted (error -28)
(...)
[30670.163567] Call Trace:
[30670.163906]  [<ffffffff8142fa46>] dump_stack+0x4f/0x7b
[30670.164522]  [<ffffffff8108b6a2>] ? console_unlock+0x361/0x3ad
[30670.165171]  [<ffffffff81045ea5>] warn_slowpath_common+0xa1/0xbb
[30670.166323]  [<ffffffffa035daa7>] ? __btrfs_abort_transaction+0x52/0x106 [btrfs]
[30670.167213]  [<ffffffff81045f05>] warn_slowpath_fmt+0x46/0x48
[30670.167862]  [<ffffffffa035daa7>] __btrfs_abort_transaction+0x52/0x106 [btrfs]
[30670.169116]  [<ffffffffa03743d7>] btrfs_create_pending_block_groups+0x101/0x130 [btrfs]
[30670.170593]  [<ffffffffa038426a>] __btrfs_end_transaction+0x84/0x366 [btrfs]
[30670.171960]  [<ffffffffa038455c>] btrfs_end_transaction+0x10/0x12 [btrfs]
[30670.174649]  [<ffffffffa036eb6b>] btrfs_check_data_free_space+0x11f/0x27c [btrfs]
[30670.176092]  [<ffffffffa039450d>] btrfs_fallocate+0x7c8/0xb96 [btrfs]
[30670.177218]  [<ffffffff812459f2>] ? __this_cpu_preempt_check+0x13/0x15
[30670.178622]  [<ffffffff81152447>] vfs_fallocate+0x14c/0x1de
[30670.179642]  [<ffffffff8116b915>] ? __fget_light+0x2d/0x4f
[30670.180692]  [<ffffffff81152863>] SyS_fallocate+0x47/0x62
[30670.186737]  [<ffffffff81435b32>] system_call_fastpath+0x12/0x17
[30670.187792] ---[ end trace 0373e6b491c4a8cc ]---

This is because we don't do proper space reservation for the chunk block
reserve when we have multiple tasks allocating chunks in parallel.

So block group creation has 2 phases, and the first phase essentially
checks if there is enough space in the system space_info, allocating a
new system chunk if there isn't, while the second phase updates the
device, extent and chunk trees. However, because the updates to the
chunk tree happen in the second phase, if we have N tasks, each with
its own transaction handle, allocating new chunks in parallel and if
there is only enough space in the system space_info to allocate M chunks,
where M < N, none of the tasks ends up allocating a new system chunk in
the first phase and N - M tasks will get -ENOSPC when attempting to
update the chunk tree in phase 2 if they need to COW any nodes/leafs
from the chunk tree.

Fix this by doing proper reservation in the chunk block reserve.

The issue could be reproduced by running fstests generic/038 in a loop,
which eventually triggered the problem.
Signed-off-by: NFilipe Manana <fdmanana@suse.com>
Signed-off-by: NChris Mason <clm@fb.com>

We should be doing this, it's weird we hadn't been doing this.
Signed-off-by: NJosef Bacik <jbacik@fb.com>
Signed-off-by: NChris Mason <clm@fb.com>

Now that we're guaranteed to have a meaningful root dentry, we can just
export seq_dentry() and use it in btrfs_show_options(). The subvolume ID
is easy to get and can also be useful, so put that in there, too.
Reviewed-by: NDavid Sterba <dsterba@suse.cz>
Signed-off-by: NOmar Sandoval <osandov@osandov.com>
Signed-off-by: NChris Mason <clm@fb.com>

Currently, mounting a subvolume with subvolid= takes a different code
path than mounting with subvol=. This isn't really a big deal except for
the fact that mounts done with subvolid= or the default subvolume don't
have a dentry that's connected to the dentry tree like in the subvol=
case. To unify the code paths, when given subvolid= or using the default
subvolume ID, translate it into a subvolume name by walking
ROOT_BACKREFs in the root tree and INODE_REFs in the filesystem trees.
Reviewed-by: NDavid Sterba <dsterba@suse.cz>
Signed-off-by: NOmar Sandoval <osandov@osandov.com>
Signed-off-by: NChris Mason <clm@fb.com>

There's nothing to stop a user from passing both subvol= and subvolid=
to mount, but if they don't refer to the same subvolume, someone is
going to be surprised at some point. Error out on this case, but allow
users to pass in both if they do match (which they could, for example,
get out of /proc/mounts).
Reviewed-by: NDavid Sterba <dsterba@suse.cz>
Signed-off-by: NOmar Sandoval <osandov@osandov.com>
Signed-off-by: NChris Mason <clm@fb.com>

In preparation for new functionality in mount_subvol(), give it
ownership of subvol_name and tidy up the error paths.
Reviewed-by: NDavid Sterba <dsterba@suse.cz>
Signed-off-by: NOmar Sandoval <osandov@osandov.com>
Signed-off-by: NChris Mason <clm@fb.com>

Currently, setup_root_args() substitutes 's/subvol=[^,]*/subvolid=0/'.
But, this means that if the user passes both a subvol and subvolid for
some reason, we won't actually mount the top-level when we recursively
mount. For example, consider:

mkfs.btrfs -f /dev/sdb
mount /dev/sdb /mnt
btrfs subvol create /mnt/subvol1 # subvolid=257
btrfs subvol create /mnt/subvol2 # subvolid=258
umount /mnt
mount -osubvol=/subvol1,subvolid=258 /dev/sdb /mnt

In the final mount, subvol=/subvol1,subvolid=258 becomes
subvolid=0,subvolid=258, and the last option takes precedence, so we
mount subvol2 and try to look up subvol1 inside of it, which fails.

So, instead, do a thorough scan through the argument list and remove any
subvol= and subvolid= options, then append subvolid=0 to the end. This
implicitly makes subvol= take precedence over subvolid=, but we're about
to add a stricter check for that. This also makes setup_root_args() more
generic, which we'll need soon.
Reviewed-by: NDavid Sterba <dsterba@suse.cz>
Signed-off-by: NOmar Sandoval <osandov@osandov.com>
Signed-off-by: NChris Mason <clm@fb.com>

Since commit 0723a047 ("btrfs: allow mounting btrfs subvolumes with
different ro/rw options"), when mounting a subvolume read/write when
another subvolume has previously been mounted read-only, we first do a
remount. However, this should be done with the superblock locked, as per
sync_filesystem():

	/*
	 * We need to be protected against the filesystem going from
	 * r/o to r/w or vice versa.
	 */
	WARN_ON(!rwsem_is_locked(&sb->s_umount));

This WARN_ON can easily be hit with:

mkfs.btrfs -f /dev/vdb
mount /dev/vdb /mnt
btrfs subvol create /mnt/vol1
btrfs subvol create /mnt/vol2
umount /mnt
mount -oro,subvol=/vol1 /dev/vdb /mnt
mount -orw,subvol=/vol2 /dev/vdb /mnt2

Fixes: 0723a047 ("btrfs: allow mounting btrfs subvolumes with different ro/rw options")
Reviewed-by: NDavid Sterba <dsterba@suse.cz>
Signed-off-by: NOmar Sandoval <osandov@osandov.com>
Signed-off-by: NChris Mason <clm@fb.com>

When we clear an extent state's EXTENT_LOCKED bit with clear_extent_bits()
through free_io_failure(), we weren't waking up any tasks waiting for the
extent's state EXTENT_LOCKED bit, leading to an hang.

So make sure clear_extent_bits() ends up waking up any waiters if the
bit EXTENT_LOCKED is supplied by its callers.

Zygo Blaxell was experiencing such hangs at inode eviction time after
file unlinks. Thanks to him for a set of scripts to reproduce the issue.
Reported-by: NZygo Blaxell <ce3g8jdj@umail.furryterror.org>
Signed-off-by: NFilipe Manana <fdmanana@suse.com>
Reviewed-by: NLiu Bo <bo.li.liu@oracle.com>
Signed-off-by: NChris Mason <clm@fb.com>

With commit 1b984508 ("Btrfs: fix find_free_dev_extent() malfunction
in case device tree has hole") introduced in the kernel 4.1 merge window,
we end up using part of a device hole for which there are already pending
chunks or pinned chunks. Before that commit we didn't use the hole and
would just move on to the next hole in the device.

However when we adjust the start offset for the chunk allocation and we
have pinned chunks, we set it blindly to the end offset of the pinned
chunk we are currently processing, which is dangerous because we can
have a pending chunk that has a start offset that matches the end offset
of our pinned chunk - leading us to a case where we end up getting two
pending chunks that start at the same physical device offset, which makes
us later abort the current transaction with -EEXIST when finishing the
chunk allocation at btrfs_create_pending_block_groups():

[194737.659017] ------------[ cut here ]------------
[194737.660192] WARNING: CPU: 15 PID: 31111 at fs/btrfs/super.c:260 __btrfs_abort_transaction+0x52/0x106 [btrfs]()
[194737.662209] BTRFS: Transaction aborted (error -17)
[194737.663175] Modules linked in: btrfs dm_snapshot dm_bufio dm_flakey dm_mod crc32c_generic xor raid6_pq nfsd auth_rpcgss oid_registry nfs_acl nfs lockd grace fscache sunrpc loop fuse
[194737.674015] CPU: 15 PID: 31111 Comm: xfs_io Tainted: G        W       4.0.0-rc5-btrfs-next-9+ #2
[194737.675986] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.7.5-0-ge51488c-20140602_164612-nilsson.home.kraxel.org 04/01/2014
[194737.682999]  0000000000000009 ffff8800564c7a98 ffffffff8142fa46 ffffffff8108b6a2
[194737.684540]  ffff8800564c7ae8 ffff8800564c7ad8 ffffffff81045ea5 ffff8800564c7b78
[194737.686017]  ffffffffa0383aa7 00000000ffffffef ffff88000c7ba000 ffff8801a1f66f40
[194737.687509] Call Trace:
[194737.688068]  [<ffffffff8142fa46>] dump_stack+0x4f/0x7b
[194737.689027]  [<ffffffff8108b6a2>] ? console_unlock+0x361/0x3ad
[194737.690095]  [<ffffffff81045ea5>] warn_slowpath_common+0xa1/0xbb
[194737.691198]  [<ffffffffa0383aa7>] ? __btrfs_abort_transaction+0x52/0x106 [btrfs]
[194737.693789]  [<ffffffff81045f05>] warn_slowpath_fmt+0x46/0x48
[194737.695065]  [<ffffffffa0383aa7>] __btrfs_abort_transaction+0x52/0x106 [btrfs]
[194737.696806]  [<ffffffffa039a3bd>] btrfs_create_pending_block_groups+0x101/0x130 [btrfs]
[194737.698683]  [<ffffffffa03aa433>] __btrfs_end_transaction+0x84/0x366 [btrfs]
[194737.700329]  [<ffffffffa03aa725>] btrfs_end_transaction+0x10/0x12 [btrfs]
[194737.701924]  [<ffffffffa0394b51>] btrfs_check_data_free_space+0x11f/0x27c [btrfs]
[194737.703675]  [<ffffffffa03b8ba4>] __btrfs_buffered_write+0x16a/0x4c8 [btrfs]
[194737.705417]  [<ffffffffa03bb502>] ? btrfs_file_write_iter+0x19a/0x431 [btrfs]
[194737.707058]  [<ffffffffa03bb511>] ? btrfs_file_write_iter+0x1a9/0x431 [btrfs]
[194737.708560]  [<ffffffffa03bb68d>] btrfs_file_write_iter+0x325/0x431 [btrfs]
[194737.710673]  [<ffffffff81067d85>] ? get_parent_ip+0xe/0x3e
[194737.712076]  [<ffffffff811534c3>] new_sync_write+0x7c/0xa0
[194737.713293]  [<ffffffff81153b58>] vfs_write+0xb2/0x117
[194737.714443]  [<ffffffff81154424>] SyS_pwrite64+0x64/0x82
[194737.715646]  [<ffffffff81435b32>] system_call_fastpath+0x12/0x17
[194737.717175] ---[ end trace f2d5dc04e56d7e48 ]---
[194737.718170] BTRFS: error (device sdc) in btrfs_create_pending_block_groups:9524: errno=-17 Object already exists

The -EEXIST failure comes from btrfs_finish_chunk_alloc(), called by
btrfs_create_pending_block_groups(), when it attempts to insert a
duplicated device extent item via btrfs_alloc_dev_extent().

This issue was reproducible with fstests generic/038 running in a loop for
several hours (it's very hard to hit) and using MOUNT_OPTIONS="-o discard".
Applying Jeff's recent patch titled "btrfs: add missing discards when
unpinning extents with -o discard" makes the issue much easier to reproduce
(usually within 4 to 5 hours), since it pins chunks for longer periods of
time when an unused block group is deleted by the cleaner kthread.

Fix this by making sure that we never adjust the start offset to a lower
value than it currently has.

Fixes: 1b984508 ("Btrfs: fix find_free_dev_extent() malfunction in case device tree has hole"
Signed-off-by: NFilipe Manana <fdmanana@suse.com>
Signed-off-by: NChris Mason <clm@fb.com>

__btrfs_close_devices() would call_rcu to free the device, which is racy with
list_for_each_entry() accessing the memory to retrieve the next device on the
list.
Signed-off-by: NSasha Levin <sasha.levin@oracle.com>
Reviewed-by: NDavid Sterba <dsterba@suse.cz>
Signed-off-by: NChris Mason <clm@fb.com>

The INO_LOOKUP ioctl can lookup path for a given inode number and is
thus restricted. As a sideefect it can find the root id of the
containing subvolume and we're using this int the 'btrfs inspect rootid'
command.

The restriction is unnecessary in case we set the ioctl args
 args::treeid    = 0
 args::objectid  = 256 (BTRFS_FIRST_FREE_OBJECTID)

Then the path will be empty and the treeid is filled with the root id of
the inode on which the ioctl is called. This behaviour is unchanged,
after the root restriction is removed.
Signed-off-by: NDavid Sterba <dsterba@suse.cz>
Signed-off-by: NChris Mason <clm@fb.com>

When we create a block group we add it to the rbtree of block groups
before setting its ->space_info field (while it's NULL). This is
problematic since other tasks can access the block group from the
rbtree and attempt to use its ->space_info before it is set by
btrfs_make_block_group().

This can happen for example when a concurrent fitrim ioctl operation
is ongoing, which produces a trace like the following when
CONFIG_DEBUG_PAGEALLOC is set.

[11509.604369] BUG: unable to handle kernel NULL pointer dereference at 0000000000000018
[11509.606373] IP: [<ffffffff8107d675>] __lock_acquire+0xb4/0xf02
[11509.608179] PGD 2296a8067 PUD 22f4a2067 PMD 0
[11509.608179] Oops: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC
[11509.608179] Modules linked in: btrfs crc32c_generic xor raid6_pq nfsd auth_rpcgss oid_registry nfs_acl nfs lockd grace fscache sunrpc loop fuse acpi_cpufreq processor i2c_piix4 psmou
[11509.608179] CPU: 10 PID: 8538 Comm: fstrim Tainted: G        W       4.0.0-rc5-btrfs-next-9+ #2
[11509.608179] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.7.5-0-ge51488c-20140602_164612-nilsson.home.kraxel.org 04/01/2014
[11509.608179] task: ffff88009f5c46d0 ti: ffff8801b3edc000 task.ti: ffff8801b3edc000
[11509.608179] RIP: 0010:[<ffffffff8107d675>]  [<ffffffff8107d675>] __lock_acquire+0xb4/0xf02
[11509.608179] RSP: 0018:ffff8801b3edf9e8  EFLAGS: 00010002
[11509.608179] RAX: 0000000000000046 RBX: 0000000000000000 RCX: 0000000000000000
[11509.608179] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000018
[11509.608179] RBP: ffff8801b3edfaa8 R08: 0000000000000001 R09: 0000000000000000
[11509.608179] R10: 0000000000000000 R11: ffff88009f5c4f98 R12: 0000000000000000
[11509.608179] R13: 0000000000000000 R14: 0000000000000018 R15: ffff88009f5c46d0
[11509.608179] FS:  00007f280a10e840(0000) GS:ffff88023ed40000(0000) knlGS:0000000000000000
[11509.608179] CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
[11509.608179] CR2: 0000000000000018 CR3: 00000002119bc000 CR4: 00000000000006e0
[11509.608179] Stack:
[11509.608179]  0000000000000000 0000000000000000 0000000000000004 0000000000000000
[11509.608179]  ffff880100000000 ffffffff00000000 0000000000000001 ffffffff00000000
[11509.608179]  0000000000000001 0000000000000000 ffff880100000000 00000000000006c4
[11509.608179] Call Trace:
[11509.608179]  [<ffffffff8107dc57>] ? __lock_acquire+0x696/0xf02
[11509.608179]  [<ffffffff8107e806>] lock_acquire+0xa5/0x116
[11509.608179]  [<ffffffffa04cc876>] ? do_trimming+0x51/0x145 [btrfs]
[11509.608179]  [<ffffffff81434f37>] _raw_spin_lock+0x34/0x44
[11509.608179]  [<ffffffffa04cc876>] ? do_trimming+0x51/0x145 [btrfs]
[11509.608179]  [<ffffffffa04cc876>] do_trimming+0x51/0x145 [btrfs]
[11509.608179]  [<ffffffffa04cde7d>] btrfs_trim_block_group+0x201/0x491 [btrfs]
[11509.608179]  [<ffffffffa04849e2>] btrfs_trim_fs+0xe0/0x129 [btrfs]
[11509.608179]  [<ffffffffa04bb80a>] btrfs_ioctl_fitrim+0x138/0x167 [btrfs]
[11509.608179]  [<ffffffffa04c002f>] btrfs_ioctl+0x50d/0x21e8 [btrfs]
[11509.608179]  [<ffffffff81123bda>] ? might_fault+0x58/0xb5
[11509.608179]  [<ffffffff81123bda>] ? might_fault+0x58/0xb5
[11509.608179]  [<ffffffff81123bda>] ? might_fault+0x58/0xb5
[11509.608179]  [<ffffffff81158050>] ? cp_new_stat+0x147/0x15e
[11509.608179]  [<ffffffff81163041>] do_vfs_ioctl+0x3c6/0x479
[11509.608179]  [<ffffffff81158116>] ? SYSC_newfstat+0x25/0x2e
[11509.608179]  [<ffffffff81435b54>] ? ret_from_sys_call+0x1d/0x58
[11509.608179]  [<ffffffff8116b915>] ? __fget_light+0x2d/0x4f
[11509.608179]  [<ffffffff8116314e>] SyS_ioctl+0x5a/0x7f
[11509.608179]  [<ffffffff81435b32>] system_call_fastpath+0x12/0x17
[11509.608179] Code: f4 01 00 0f 85 c0 00 00 00 48 c7 c1 f3 1f 7d 81 48 c7 c2 aa cb 7c 81 be fc 0b 00 00 eb 70 83 3d 61 eb 9c 00 00 0f 84 a5 00 00 00 <49> 81 3e 40 a3 2b 82 b8 00 00 00
[11509.608179] RIP  [<ffffffff8107d675>] __lock_acquire+0xb4/0xf02
[11509.608179]  RSP <ffff8801b3edf9e8>
[11509.608179] CR2: 0000000000000018
[11509.608179] ---[ end trace 570a5c6769f0e49a ]---

Which corresponds to the following access in fs/btrfs/free-space-cache.c:

  static int do_trimming(struct btrfs_block_group_cache *block_group,
                         u64 *total_trimmed, u64 start, u64 bytes,
                         u64 reserved_start, u64 reserved_bytes,
                         struct btrfs_trim_range *trim_entry)
  {
       struct btrfs_space_info *space_info = block_group->space_info;
  (...)
       spin_lock(&space_info->lock);
       ^^^^^ - block_group->space_info is NULL...

Fix this by ensuring the block group's ->space_info is set before adding
the block group to the rbtree.
Signed-off-by: NFilipe Manana <fdmanana@suse.com>
Signed-off-by: NChris Mason <clm@fb.com>

Report missing device when add is successful,
otherwise it would exit as ENOMEM. And add uuid
to the report.
Signed-off-by: NAnand Jain <anand.jain@oracle.com>
Reviewed-by: NDavid Sterba <dsterba@suse.cz>
Signed-off-by: NChris Mason <clm@fb.com>

Old csum type check is wrong and can't catch csum_type 1(not supported).

Fix it to avoid hostile 0 division.
Reported-by: NLukas Lueg <lukas.lueg@gmail.com>
Signed-off-by: NQu Wenruo <quwenruo@cn.fujitsu.com>
Reviewed-by: NDavid Sterba <dsterba@suse.cz>
Signed-off-by: NChris Mason <clm@fb.com>

Marc reported a problem where the receiving end of an incremental send
was performing clone operations that failed with -EINVAL. This happened
because, unlike for uncompressed extents, we were not checking if the
source clone offset and length, after summing the data offset, falls
within the source file's boundaries.

So make sure we do such checks when attempting to issue clone operations
for compressed extents.

Problem reproducible with the following steps:

  $ mkfs.btrfs -f /dev/sdb
  $ mount -o compress /dev/sdb /mnt
  $ mkfs.btrfs -f /dev/sdc
  $ mount -o compress /dev/sdc /mnt2

  # Create the file with a single extent of 128K. This creates a metadata file
  # extent item with a data start offset of 0 and a logical length of 128K.
  $ xfs_io -f -c "pwrite -S 0xaa 64K 128K" -c "fsync" /mnt/foo

  # Now rewrite the range 64K to 112K of our file. This will make the inode's
  # metadata continue to point to the 128K extent we created before, but now
  # with an extent item that points to the extent with a data start offset of
  # 112K and a logical length of 16K.
  # That metadata file extent item is associated with the logical file offset
  # at 176K and covers the logical file range 176K to 192K.
  $ xfs_io -c "pwrite -S 0xbb 64K 112K" -c "fsync" /mnt/foo

  # Now rewrite the range 180K to 12K. This will make the inode's metadata
  # continue to point the the 128K extent we created earlier, with a single
  # extent item that points to it with a start offset of 112K and a logical
  # length of 4K.
  # That metadata file extent item is associated with the logical file offset
  # at 176K and covers the logical file range 176K to 180K.
  $ xfs_io -c "pwrite -S 0xcc 180K 12K" -c "fsync" /mnt/foo

  $ btrfs subvolume snapshot -r /mnt /mnt/snap1

  $ touch /mnt/bar
  # Calls the btrfs clone ioctl.
  $ ~/xfstests/src/cloner -s $((176 * 1024)) -d $((176 * 1024)) \
    -l $((4 * 1024)) /mnt/foo /mnt/bar

  $ btrfs subvolume snapshot -r /mnt /mnt/snap2

  $ btrfs send /mnt/snap1 | btrfs receive /mnt2
  At subvol /mnt/snap1
  At subvol snap1

  $ btrfs send -p /mnt/snap1 /mnt/snap2 | btrfs receive /mnt2
  At subvol /mnt/snap2
  At snapshot snap2
  ERROR: failed to clone extents to bar
  Invalid argument

A test case for fstests follows soon.
Reported-by: NMarc MERLIN <marc@merlins.org>
Tested-by: NMarc MERLIN <marc@merlins.org>
Signed-off-by: NFilipe Manana <fdmanana@suse.com>
Tested-by: NDavid Sterba <dsterba@suse.cz>
Tested-by: NJan Alexander Steffens (heftig) <jan.steffens@gmail.com>
Signed-off-by: NChris Mason <clm@fb.com>

Commit 9c8b35b1 ("btrfs: quota: Automatically update related qgroups or
mark INCONSISTENT flags when assigning/deleting a qgroup relations.")
introduced the allocation of a temporary ulist in function
btrfs_add_qgroup_relation() and added the corresponding cleanup to the out
path. However, the allocation was introduced before the src/dst level check
that directly returns. Fix the possible leakage of the ulist by moving the
allocation after the input validation. Detected by Coverity CID 1295988.
Signed-off-by: NChristian Engelmayer <cengelma@gmx.at>
Reviewed-by: NDavid Sterba <dsterba@suse.cz>
Signed-off-by: NChris Mason <clm@fb.com>

If the call to btrfs_truncate_inode_items() failed and we don't have a block
group, we were unlocking the cache_write_mutex without having locked it (we
do it only if we have a block group).

Fixes: 1bbc621e ("Btrfs: allow block group cache writeout
                      outside critical section in commit")
Signed-off-by: NFilipe Manana <fdmanana@suse.com>
Reviewed-by: NDavid Sterba <dsterba@suse.cz>
Signed-off-by: NChris Mason <clm@fb.com>

Signed-off-by: NAnand Jain <anand.jain@oracle.com>
Reviewed-by: NDavid Sterba <dsterba@suse.cz>
Signed-off-by: NChris Mason <clm@fb.com>

fs/btrfs/volumes.c: In function ‘btrfs_create_uuid_tree’:
fs/btrfs/volumes.c:3909:3: warning: format ‘%d’ expects argument of type ‘int’, but argument 4 has type ‘long int’ [-Wformat=]
   btrfs_abort_transaction(trans, tree_root,
   ^
  CC [M]  fs/btrfs/ioctl.o
fs/btrfs/ioctl.c: In function ‘create_subvol’:
fs/btrfs/ioctl.c:549:3: warning: format ‘%d’ expects argument of type ‘int’, but argument 4 has type ‘long int’ [-Wformat=]
   btrfs_abort_transaction(trans, root, PTR_ERR(new_root));

PTR_ERR returns long, but we're really using 'int' for the error codes
everywhere so just set and use the local variable.
Signed-off-by: NDavid Sterba <dsterba@suse.cz>
Signed-off-by: NChris Mason <clm@fb.com>

The annotated functios will be placed into .text.unlikely section. The
annotation also hints compiler to move the code out of the hot paths,
and may implicitly mark if-statement leading to that block as unlikely.

This is a heuristic, the impact on the generated code is not
significant.
Signed-off-by: NDavid Sterba <dsterba@suse.cz>
Signed-off-by: NChris Mason <clm@fb.com>

WARN is called from a single location and all bugreports say that's in
super.c __btrfs_abort_transaction. This is slightly confusing as we'd
rather want to know the exact callsite. Whereas this information is
printed in the syslog below the stacktrace, this requires further look
and we usually see only the headline from WARNING.

Moving the WARN into the macro has to inline some code and increases
code by a few kilobytes:

  text    data     bss     dec     hex filename
835481   20305   14120  869906   d4612 btrfs.ko.before
842883   20305   14120  877308   d62fc btrfs.ko.after

The delta is +7k (130+ calls), measured on 3.19 x86_64, distro config.
The increase is not small and could lead to worse icache use. The code
is on error/exit paths that can be recognized by compiler as cold and
moved out of the way so the impact is speculated to be low, if
measurable at all.
Signed-off-by: NDavid Sterba <dsterba@suse.cz>
Signed-off-by: NChris Mason <clm@fb.com>

Long time ago (2008) the defrag was automatic for new b-tree writes but
has been disabled after performance problems. There was a leftover in
tree-defrag.c that effectively stops any defragmentation on b-trees.
This is a bit unexpected and IMHO undesired. The SSD mode is an
optimization and defrag is supposed to work if the users asks for it.

Related commits:

6702ed49
Btrfs: Add run time btree defrag, and an ioctl to force btree defrag

e18e4809
Btrfs: Add mount -o ssd, which includes optimizations for seek free
storage

b3236e68
Btrfs: Leave on the tree defragger in mount -o ssd, it still helps there

9afbb0b7
Btrfs: Disable tree defrag in SSD mode

The last three commits switch the defrag+ssd off/on/off and the last one

3f157a2f
Btrfs: Online btree defragmentation fixes

misses the bits from tree-defrag.c to revert to the behaviour introduced
in e18e4809.
Signed-off-by: NDavid Sterba <dsterba@suse.cz>
Signed-off-by: NChris Mason <clm@fb.com>

When we shrink the usable size of a device (its total_bytes), we go over
all the device extent items in the device tree and attempt to relocate
the chunk of any device extent that goes beyond the new usable size for
the device. We do that after setting the new usable size (total_bytes) in
the device object, so that all new allocations (and reallocations) don't
use areas of the device that go beyond the new (shorter) size. However we
were not considering that before setting the new size in the device,
pending chunks might have been created that use device extents that go
beyond the new size, and those device extents are not yet in the device
tree after we search the device tree - they are still attached to the
list of new block group for some ongoing transaction handle, and they are
only added to the device tree when the transaction handle is ended (via
btrfs_create_pending_block_groups()).

So check for pending chunks with device extents that go beyond the new
size and if any exists, commit the current transaction and repeat the
search in the device tree.

Not doing this it would mean we would return success to user space while
still having extents that go beyond the new size, and later user space
could override those locations on the device while the fs still references
them, causing all sorts of corruption and unexpected events.
Signed-off-by: NFilipe Manana <fdmanana@suse.com>
Signed-off-by: NChris Mason <clm@fb.com>

Since commit bafc9b75 ("vfs: More precise tests in d_invalidate"),
mounted subvolumes can be deleted because d_invalidate() won't fail.
However, we run into problems when we attempt to delete the default
subvolume while it is mounted as the root filesystem:

	# btrfs subvol list /
	ID 257 gen 306 top level 5 path rootvol
	ID 267 gen 334 top level 5 path snap1
	# btrfs subvol get-default /
	ID 267 gen 334 top level 5 path snap1
	# btrfs inspect-internal rootid /
	267
	# mount -o subvol=/ /dev/vda1 /mnt
	# btrfs subvol del /mnt/snap1
	Delete subvolume (no-commit): '/mnt/snap1'
	ERROR: cannot delete '/mnt/snap1' - Operation not permitted
	# findmnt /
	findmnt: can't read /proc/mounts: No such file or directory
	# ls /proc
	#

Markus reported that this same scenario simply led to a kernel oops.

This happens because in btrfs_ioctl_snap_destroy(), we call
d_invalidate() before we check may_destroy_subvol(), which means that we
detach the submounts and drop the dentry before erroring out. Instead,
we should only invalidate the dentry once the deletion has succeeded.
Additionally, the shrink_dcache_sb() isn't necessary; d_invalidate()
will prune the dcache for the deleted subvolume.

Cc: <stable@vger.kernel.org>
Fixes: bafc9b75 ("vfs: More precise tests in d_invalidate")
Reported-by: NMarkus Schauler <mschauler@gmail.com>
Signed-off-by: NOmar Sandoval <osandov@osandov.com>
Signed-off-by: NChris Mason <clm@fb.com>

Pull vfs fix from Al Viro:
 "Off-by-one in d_walk()/__dentry_kill() race fix.

  It's very hard to hit; possible in the same conditions as the original
  bug, except that you need the skipped branch to contain all the
  remaining evictables, so that the d_walk()-calling loop in
  d_invalidate() decides there's nothing more to do and doesn't go for
  another pass - otherwise that next pass will sweep the sucker.

  So it's not too urgent, but seeing that the fix is obvious and the
  original commit has spread into all -stable branches..."

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  d_walk() might skip too much

Pull ARM fixes from Russell King:
 "Three fixes this time around:

   - fix a memory leak which occurs when probing performance monitoring
     unit interrupts

   - fix handling of non-PMD aligned end of RAM causing boot failures

   - fix missing syscall trace exit path with syscall tracing enabled
     causing a kernel oops in the audit code"

* 'fixes' of git://ftp.arm.linux.org.uk/~rmk/linux-arm:
  ARM: 8357/1: perf: fix memory leak when probing PMU PPIs
  ARM: fix missing syscall trace exit
  ARM: 8356/1: mm: handle non-pmd-aligned end of RAM

Pull MIPS fixes from Ralf Baechle:
 "MIPS fixes for 4.1 all across the tree"

* 'upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/ralf/linux:
  MIPS: strnlen_user.S: Fix a CPU_DADDI_WORKAROUNDS regression
  MIPS: BMIPS: Fix bmips_wr_vec()
  MIPS: ath79: fix build problem if CONFIG_BLK_DEV_INITRD is not set
  MIPS: Fuloong 2E: Replace CONFIG_USB_ISP1760_HCD by CONFIG_USB_ISP1760
  MIPS: irq: Use DECLARE_BITMAP
  ttyFDC: Fix to use native endian MMIO reads
  MIPS: Fix CDMM to use native endian MMIO reads

Pull turbostat tool fixes from Len Brown:
 "Just one minor kernel dependency in this batch -- added a #define to
  msr-index.h"

* 'turbostat' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux:
  tools/power turbostat: update version number to 4.7
  tools/power turbostat: allow running without cpu0
  tools/power turbostat: correctly decode of ENERGY_PERFORMANCE_BIAS
  tools/power turbostat: enable turbostat to support Knights Landing (KNL)
  tools/power turbostat: correctly display more than 2 threads/core

Pull SCSI target fixes from Nicholas Bellinger:
 "These are mostly minor fixes, with the exception of the following that
  address fall-out from recent v4.1-rc1 changes:

   - regression fix related to the big fabric API registration changes
     and configfs_depend_item() usage, that required cherry-picking one
     of HCH's patches from for-next to address the issue for v4.1 code.

   - remaining TCM-USER -v2 related changes to enforce full CDB
     passthrough from Andy + Ilias.

  Also included is a target_core_pscsi driver fix from Andy that
  addresses a long standing issue with a Scsi_Host reference being
  leaked on PSCSI device shutdown"

* git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending:
  iser-target: Fix error path in isert_create_pi_ctx()
  target: Use a PASSTHROUGH flag instead of transport_types
  target: Move passthrough CDB parsing into a common function
  target/user: Only support full command pass-through
  target/user: Update example code for new ABI requirements
  target/pscsi: Don't leak scsi_host if hba is VIRTUAL_HOST
  target: Fix se_tpg_tfo->tf_subsys regression + remove tf_subsystem
  target: Drop signal_pending checks after interruptible lock acquire
  target: Add missing parentheses
  target: Fix bidi command handling
  target/user: Disallow full passthrough (pass_level=0)
  ISCSI: fix minor memory leak

Merge tag 'hwmon-for-linus-v4.1-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging

Pull hwmon fixes from Guenter Roeck:
 "Some late hwmon patches, all headed for -stable

   - fix sysfs attribute initialization in nct6775 and nct6683 drivers

   - do not attempt to auto-detect tmp435 on I2C address 0x37

   - ensure iio channel is of type IIO_VOLTAGE in ntc_thermistor driver"

* tag 'hwmon-for-linus-v4.1-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging:
  hwmon: (nct6683) Add missing sysfs attribute initialization
  hwmon: (nct6775) Add missing sysfs attribute initialization
  hwmon: (tmp401) Do not auto-detect chip on I2C address 0x37
  hwmon: (ntc_thermistor) Ensure iio channel is of type IIO_VOLTAGE

We don't assign pi_ctx to desc->pi_ctx until we're certain to succeed
in the function.  That means the cleanup path should use the local
pi_ctx variable, not desc->pi_ctx.

This was detected by Coverity (CID 1260062).
Signed-off-by: NRoland Dreier <roland@purestorage.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

It seems like we only care if a transport is passthrough or not. Convert
transport_type to a flags field and replace TRANSPORT_PLUGIN_* with a
flag, TRANSPORT_FLAG_PASSTHROUGH.
Signed-off-by: NAndy Grover <agrover@redhat.com>
Reviewed-by: NIlias Tsitsimpis <iliastsi@arrikto.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Aside from whether they handle BIDI ops or not, parsing of the CDB by
kernel and user SCSI passthrough modules should be identical. Move this
into a new passthrough_parse_cdb() and call it from tcm-pscsi and tcm-user.
Reported-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NIlias Tsitsimpis <iliastsi@arrikto.com>
Signed-off-by: NAndy Grover <agrover@redhat.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

After much discussion, give up on only passing a subset of SCSI commands
to userspace and pass them all. Based on what pscsi is doing, make sure
to set SCF_SCSI_DATA_CDB for I/O ops, and define attributes identical to
pscsi.

Make hw_block_size configurable via dev param.

Remove mention of command filtering from tcmu-design.txt.
Signed-off-by: NAndy Grover <agrover@redhat.com>
Reviewed-by: NIlias Tsitsimpis <iliastsi@arrikto.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

We now require that the userspace handler set a bit if the command is not
handled.

Update calls to tcmu_hdr_get_op for v2.
Signed-off-by: NAndy Grover <agrover@redhat.com>
Reviewed-by: NIlias Tsitsimpis <iliastsi@arrikto.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

See https://bugzilla.redhat.com/show_bug.cgi?id=1025672

We need to put() the reference to the scsi host that we got in
pscsi_configure_device(). In VIRTUAL_HOST mode it is associated with
the dev_virt, not the hba_virt.
Signed-off-by: NAndy Grover <agrover@redhat.com>
Cc: stable@vger.kernel.org # 2.6.38+
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

There is just one configfs subsystem in the target code, so we might as
well add two helpers to reference / unreference it from the core code
instead of passing pointers to it around.

This fixes a regression introduced for v4.1-rc1 with commit 9ac8928e,
where configfs_depend_item() callers using se_tpg_tfo->tf_subsys would
fail, because the assignment from the original target_core_subsystem[]
is no longer happening at target_register_template() time.

(Fix target_core_exit_configfs pointer dereference - Sagi)
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reported-by: NHimanshu Madhani <himanshu.madhani@qlogic.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

The following error message is seen when loading the nct6683 driver
with DEBUG_LOCK_ALLOC enabled.

BUG: key ffff88040b2f0030 not in .data!
------------[ cut here ]------------
WARNING: CPU: 0 PID: 186 at kernel/locking/lockdep.c:2988
				lockdep_init_map+0x469/0x630()
DEBUG_LOCKS_WARN_ON(1)

Caused by a missing call to sysfs_attr_init() when initializing
sysfs attributes.
Reported-by: NAlexey Orishko <alexey.orishko@gmail.com>
Reviewed-by: NJean Delvare <jdelvare@suse.de>
Cc: stable@vger.kernel.org # v3.18+
Signed-off-by: NGuenter Roeck <linux@roeck-us.net>