Commit Graph

285 Commits

Author SHA1 Message Date
David Sterba
a019e9e197 btrfs: remove extent_map::bdev
We can now remove the bdev from extent_map. Previous patches made sure
that bio_set_dev is correctly in all places and that we don't need to
grab it from latest_bdev or pass it around inside the extent map.

Signed-off-by: David Sterba <dsterba@suse.com>
2019-11-18 23:43:44 +01:00
Qu Wenruo
b12de52896 btrfs: scrub: Don't check free space before marking a block group RO
[BUG]
When running btrfs/072 with only one online CPU, it has a pretty high
chance to fail:

  btrfs/072 12s ... _check_dmesg: something found in dmesg (see xfstests-dev/results//btrfs/072.dmesg)
  - output mismatch (see xfstests-dev/results//btrfs/072.out.bad)
      --- tests/btrfs/072.out     2019-10-22 15:18:14.008965340 +0800
      +++ /xfstests-dev/results//btrfs/072.out.bad      2019-11-14 15:56:45.877152240 +0800
      @@ -1,2 +1,3 @@
       QA output created by 072
       Silence is golden
      +Scrub find errors in "-m dup -d single" test
      ...

And with the following call trace:

  BTRFS info (device dm-5): scrub: started on devid 1
  ------------[ cut here ]------------
  BTRFS: Transaction aborted (error -27)
  WARNING: CPU: 0 PID: 55087 at fs/btrfs/block-group.c:1890 btrfs_create_pending_block_groups+0x3e6/0x470 [btrfs]
  CPU: 0 PID: 55087 Comm: btrfs Tainted: G        W  O      5.4.0-rc1-custom+ #13
  Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015
  RIP: 0010:btrfs_create_pending_block_groups+0x3e6/0x470 [btrfs]
  Call Trace:
   __btrfs_end_transaction+0xdb/0x310 [btrfs]
   btrfs_end_transaction+0x10/0x20 [btrfs]
   btrfs_inc_block_group_ro+0x1c9/0x210 [btrfs]
   scrub_enumerate_chunks+0x264/0x940 [btrfs]
   btrfs_scrub_dev+0x45c/0x8f0 [btrfs]
   btrfs_ioctl+0x31a1/0x3fb0 [btrfs]
   do_vfs_ioctl+0x636/0xaa0
   ksys_ioctl+0x67/0x90
   __x64_sys_ioctl+0x43/0x50
   do_syscall_64+0x79/0xe0
   entry_SYSCALL_64_after_hwframe+0x49/0xbe
  ---[ end trace 166c865cec7688e7 ]---

[CAUSE]
The error number -27 is -EFBIG, returned from the following call chain:
btrfs_end_transaction()
|- __btrfs_end_transaction()
   |- btrfs_create_pending_block_groups()
      |- btrfs_finish_chunk_alloc()
         |- btrfs_add_system_chunk()

This happens because we have used up all space of
btrfs_super_block::sys_chunk_array.

The root cause is, we have the following bad loop of creating tons of
system chunks:

1. The only SYSTEM chunk is being scrubbed
   It's very common to have only one SYSTEM chunk.
2. New SYSTEM bg will be allocated
   As btrfs_inc_block_group_ro() will check if we have enough space
   after marking current bg RO. If not, then allocate a new chunk.
3. New SYSTEM bg is still empty, will be reclaimed
   During the reclaim, we will mark it RO again.
4. That newly allocated empty SYSTEM bg get scrubbed
   We go back to step 2, as the bg is already mark RO but still not
   cleaned up yet.

If the cleaner kthread doesn't get executed fast enough (e.g. only one
CPU), then we will get more and more empty SYSTEM chunks, using up all
the space of btrfs_super_block::sys_chunk_array.

[FIX]
Since scrub/dev-replace doesn't always need to allocate new extent,
especially chunk tree extent, so we don't really need to do chunk
pre-allocation.

To break above spiral, here we introduce a new parameter to
btrfs_inc_block_group(), @do_chunk_alloc, which indicates whether we
need extra chunk pre-allocation.

For relocation, we pass @do_chunk_alloc=true, while for scrub, we pass
@do_chunk_alloc=false.
This should keep unnecessary empty chunks from popping up for scrub.

Also, since there are two parameters for btrfs_inc_block_group_ro(),
add more comment for it.

Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2019-11-18 18:07:55 +01:00
David Sterba
32da5386d9 btrfs: rename btrfs_block_group_cache
The type name is misleading, a single entry is named 'cache' while this
normally means a collection of objects. Rename that everywhere. Also the
identifier was quite long, making function prototypes harder to format.

Suggested-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2019-11-18 17:51:51 +01:00
David Sterba
b3470b5dbe btrfs: add dedicated members for start and length of a block group
The on-disk format of block group item makes use of the key that stores
the offset and length. This is further used in the code, although this
makes thing harder to understand. The key is also packed so the
offset/length is not properly aligned as u64.

Add start (key.objectid) and length (key.offset) members to block group
and remove the embedded key.  When the item is searched or written, a
local variable for key is used.

Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2019-11-18 17:51:45 +01:00
David Sterba
bf38be65f3 btrfs: move block_group_item::used to block group
For unknown reasons, the member 'used' in the block group struct is
stored in the b-tree item and accessed everywhere using the special
accessor helper. Let's unify it and make it a regular member and only
update the item before writing it to the tree.

The item is still being used for flags and chunk_objectid, there's some
duplication until the item is removed in following patches.

Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2019-11-18 17:51:44 +01:00
David Sterba
67439dadb0 btrfs: opencode extent_buffer_get
The helper is trivial and we can understand what the atomic_inc on
something named refs does.

Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2019-11-18 12:46:54 +01:00
David Sterba
4c66e0d424 btrfs: drop unused parameter is_new from btrfs_iget
The parameter is now always set to NULL and could be dropped. The last
user was get_default_root but that got reworked in 05dbe6837b ("Btrfs:
unify subvol= and subvolid= mounting") and the parameter became unused.

Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2019-11-18 12:46:52 +01:00
Qu Wenruo
8702ba9396 btrfs: qgroup: Always free PREALLOC META reserve in btrfs_delalloc_release_extents()
[Background]
Btrfs qgroup uses two types of reserved space for METADATA space,
PERTRANS and PREALLOC.

PERTRANS is metadata space reserved for each transaction started by
btrfs_start_transaction().
While PREALLOC is for delalloc, where we reserve space before joining a
transaction, and finally it will be converted to PERTRANS after the
writeback is done.

[Inconsistency]
However there is inconsistency in how we handle PREALLOC metadata space.

The most obvious one is:
In btrfs_buffered_write():
	btrfs_delalloc_release_extents(BTRFS_I(inode), reserve_bytes, true);

We always free qgroup PREALLOC meta space.

While in btrfs_truncate_block():
	btrfs_delalloc_release_extents(BTRFS_I(inode), blocksize, (ret != 0));

We only free qgroup PREALLOC meta space when something went wrong.

[The Correct Behavior]
The correct behavior should be the one in btrfs_buffered_write(), we
should always free PREALLOC metadata space.

The reason is, the btrfs_delalloc_* mechanism works by:
- Reserve metadata first, even it's not necessary
  In btrfs_delalloc_reserve_metadata()

- Free the unused metadata space
  Normally in:
  btrfs_delalloc_release_extents()
  |- btrfs_inode_rsv_release()
     Here we do calculation on whether we should release or not.

E.g. for 64K buffered write, the metadata rsv works like:

/* The first page */
reserve_meta:	num_bytes=calc_inode_reservations()
free_meta:	num_bytes=0
total:		num_bytes=calc_inode_reservations()
/* The first page caused one outstanding extent, thus needs metadata
   rsv */

/* The 2nd page */
reserve_meta:	num_bytes=calc_inode_reservations()
free_meta:	num_bytes=calc_inode_reservations()
total:		not changed
/* The 2nd page doesn't cause new outstanding extent, needs no new meta
   rsv, so we free what we have reserved */

/* The 3rd~16th pages */
reserve_meta:	num_bytes=calc_inode_reservations()
free_meta:	num_bytes=calc_inode_reservations()
total:		not changed (still space for one outstanding extent)

This means, if btrfs_delalloc_release_extents() determines to free some
space, then those space should be freed NOW.
So for qgroup, we should call btrfs_qgroup_free_meta_prealloc() other
than btrfs_qgroup_convert_reserved_meta().

The good news is:
- The callers are not that hot
  The hottest caller is in btrfs_buffered_write(), which is already
  fixed by commit 336a8bb8e3 ("btrfs: Fix wrong
  btrfs_delalloc_release_extents parameter"). Thus it's not that
  easy to cause false EDQUOT.

- The trans commit in advance for qgroup would hide the bug
  Since commit f5fef45936 ("btrfs: qgroup: Make qgroup async transaction
  commit more aggressive"), when btrfs qgroup metadata free space is slow,
  it will try to commit transaction and free the wrongly converted
  PERTRANS space, so it's not that easy to hit such bug.

[FIX]
So to fix the problem, remove the @qgroup_free parameter for
btrfs_delalloc_release_extents(), and always pass true to
btrfs_inode_rsv_release().

Reported-by: Filipe Manana <fdmanana@suse.com>
Fixes: 43b18595d6 ("btrfs: qgroup: Use separate meta reservation type for delalloc")
CC: stable@vger.kernel.org # 4.19+
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2019-10-15 18:50:07 +02:00
Filipe Manana
44db1216ef Btrfs: add missing extents release on file extent cluster relocation error
If we error out when finding a page at relocate_file_extent_cluster(), we
need to release the outstanding extents counter on the relocation inode,
set by the previous call to btrfs_delalloc_reserve_metadata(), otherwise
the inode's block reserve size can never decrease to zero and metadata
space is leaked. Therefore add a call to btrfs_delalloc_release_extents()
in case we can't find the target page.

Fixes: 8b62f87bad ("Btrfs: rework outstanding_extents")
CC: stable@vger.kernel.org # 4.19+
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2019-10-11 19:49:11 +02:00
Qu Wenruo
1fac4a5437 btrfs: relocation: fix use-after-free on dead relocation roots
[BUG]
One user reported a reproducible KASAN report about use-after-free:

  BTRFS info (device sdi1): balance: start -dvrange=1256811659264..1256811659265
  BTRFS info (device sdi1): relocating block group 1256811659264 flags data|raid0
  ==================================================================
  BUG: KASAN: use-after-free in btrfs_init_reloc_root+0x2cd/0x340 [btrfs]
  Write of size 8 at addr ffff88856f671710 by task kworker/u24:10/261579

  CPU: 2 PID: 261579 Comm: kworker/u24:10 Tainted: P           OE     5.2.11-arch1-1-kasan #4
  Hardware name: To Be Filled By O.E.M. To Be Filled By O.E.M./X99 Extreme4, BIOS P3.80 04/06/2018
  Workqueue: btrfs-endio-write btrfs_endio_write_helper [btrfs]
  Call Trace:
   dump_stack+0x7b/0xba
   print_address_description+0x6c/0x22e
   ? btrfs_init_reloc_root+0x2cd/0x340 [btrfs]
   __kasan_report.cold+0x1b/0x3b
   ? btrfs_init_reloc_root+0x2cd/0x340 [btrfs]
   kasan_report+0x12/0x17
   __asan_report_store8_noabort+0x17/0x20
   btrfs_init_reloc_root+0x2cd/0x340 [btrfs]
   record_root_in_trans+0x2a0/0x370 [btrfs]
   btrfs_record_root_in_trans+0xf4/0x140 [btrfs]
   start_transaction+0x1ab/0xe90 [btrfs]
   btrfs_join_transaction+0x1d/0x20 [btrfs]
   btrfs_finish_ordered_io+0x7bf/0x18a0 [btrfs]
   ? lock_repin_lock+0x400/0x400
   ? __kmem_cache_shutdown.cold+0x140/0x1ad
   ? btrfs_unlink_subvol+0x9b0/0x9b0 [btrfs]
   finish_ordered_fn+0x15/0x20 [btrfs]
   normal_work_helper+0x1bd/0xca0 [btrfs]
   ? process_one_work+0x819/0x1720
   ? kasan_check_read+0x11/0x20
   btrfs_endio_write_helper+0x12/0x20 [btrfs]
   process_one_work+0x8c9/0x1720
   ? pwq_dec_nr_in_flight+0x2f0/0x2f0
   ? worker_thread+0x1d9/0x1030
   worker_thread+0x98/0x1030
   kthread+0x2bb/0x3b0
   ? process_one_work+0x1720/0x1720
   ? kthread_park+0x120/0x120
   ret_from_fork+0x35/0x40

  Allocated by task 369692:
   __kasan_kmalloc.part.0+0x44/0xc0
   __kasan_kmalloc.constprop.0+0xba/0xc0
   kasan_kmalloc+0x9/0x10
   kmem_cache_alloc_trace+0x138/0x260
   btrfs_read_tree_root+0x92/0x360 [btrfs]
   btrfs_read_fs_root+0x10/0xb0 [btrfs]
   create_reloc_root+0x47d/0xa10 [btrfs]
   btrfs_init_reloc_root+0x1e2/0x340 [btrfs]
   record_root_in_trans+0x2a0/0x370 [btrfs]
   btrfs_record_root_in_trans+0xf4/0x140 [btrfs]
   start_transaction+0x1ab/0xe90 [btrfs]
   btrfs_start_transaction+0x1e/0x20 [btrfs]
   __btrfs_prealloc_file_range+0x1c2/0xa00 [btrfs]
   btrfs_prealloc_file_range+0x13/0x20 [btrfs]
   prealloc_file_extent_cluster+0x29f/0x570 [btrfs]
   relocate_file_extent_cluster+0x193/0xc30 [btrfs]
   relocate_data_extent+0x1f8/0x490 [btrfs]
   relocate_block_group+0x600/0x1060 [btrfs]
   btrfs_relocate_block_group+0x3a0/0xa00 [btrfs]
   btrfs_relocate_chunk+0x9e/0x180 [btrfs]
   btrfs_balance+0x14e4/0x2fc0 [btrfs]
   btrfs_ioctl_balance+0x47f/0x640 [btrfs]
   btrfs_ioctl+0x119d/0x8380 [btrfs]
   do_vfs_ioctl+0x9f5/0x1060
   ksys_ioctl+0x67/0x90
   __x64_sys_ioctl+0x73/0xb0
   do_syscall_64+0xa5/0x370
   entry_SYSCALL_64_after_hwframe+0x44/0xa9

  Freed by task 369692:
   __kasan_slab_free+0x14f/0x210
   kasan_slab_free+0xe/0x10
   kfree+0xd8/0x270
   btrfs_drop_snapshot+0x154c/0x1eb0 [btrfs]
   clean_dirty_subvols+0x227/0x340 [btrfs]
   relocate_block_group+0x972/0x1060 [btrfs]
   btrfs_relocate_block_group+0x3a0/0xa00 [btrfs]
   btrfs_relocate_chunk+0x9e/0x180 [btrfs]
   btrfs_balance+0x14e4/0x2fc0 [btrfs]
   btrfs_ioctl_balance+0x47f/0x640 [btrfs]
   btrfs_ioctl+0x119d/0x8380 [btrfs]
   do_vfs_ioctl+0x9f5/0x1060
   ksys_ioctl+0x67/0x90
   __x64_sys_ioctl+0x73/0xb0
   do_syscall_64+0xa5/0x370
   entry_SYSCALL_64_after_hwframe+0x44/0xa9

  The buggy address belongs to the object at ffff88856f671100
   which belongs to the cache kmalloc-4k of size 4096
  The buggy address is located 1552 bytes inside of
   4096-byte region [ffff88856f671100, ffff88856f672100)
  The buggy address belongs to the page:
  page:ffffea0015bd9c00 refcount:1 mapcount:0 mapping:ffff88864400e600 index:0x0 compound_mapcount: 0
  flags: 0x2ffff0000010200(slab|head)
  raw: 02ffff0000010200 dead000000000100 dead000000000200 ffff88864400e600
  raw: 0000000000000000 0000000000070007 00000001ffffffff 0000000000000000
  page dumped because: kasan: bad access detected

  Memory state around the buggy address:
   ffff88856f671600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
   ffff88856f671680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
  >ffff88856f671700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                           ^
   ffff88856f671780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
   ffff88856f671800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
  ==================================================================
  BTRFS info (device sdi1): 1 enospc errors during balance
  BTRFS info (device sdi1): balance: ended with status: -28

[CAUSE]
The problem happens when finish_ordered_io() get called with balance
still running, while the reloc root of that subvolume is already dead.
(Tree is swap already done, but tree not yet deleted for possible qgroup
usage.)

That means root->reloc_root still exists, but that reloc_root can be
under btrfs_drop_snapshot(), thus we shouldn't access it.

The following race could cause the use-after-free problem:

                CPU1              |                CPU2
--------------------------------------------------------------------------
                                  | relocate_block_group()
                                  | |- unset_reloc_control(rc)
                                  | |- btrfs_commit_transaction()
btrfs_finish_ordered_io()         | |- clean_dirty_subvols()
|- btrfs_join_transaction()       |    |
   |- record_root_in_trans()      |    |
      |- btrfs_init_reloc_root()  |    |
         |- if (root->reloc_root) |    |
         |                        |    |- root->reloc_root = NULL
         |                        |    |- btrfs_drop_snapshot(reloc_root);
         |- reloc_root->last_trans|
                 = trans->transid |
	    ^^^^^^^^^^^^^^^^^^^^^^
            Use after free

[FIX]
Fix it by the following modifications:

- Test if the root has dead reloc tree before accessing root->reloc_root
  If the root has BTRFS_ROOT_DEAD_RELOC_TREE, then we don't need to
  create or update root->reloc_tree

- Clear the BTRFS_ROOT_DEAD_RELOC_TREE flag until we have fully dropped
  reloc tree
  To co-operate with above modification, so as long as
  BTRFS_ROOT_DEAD_RELOC_TREE is still set, we won't try to re-create
  reloc tree at record_root_in_trans().

Reported-by: Cebtenzzre <cebtenzzre@gmail.com>
Fixes: d2311e6985 ("btrfs: relocation: Delay reloc tree deletion after merge_reloc_roots")
CC: stable@vger.kernel.org # 5.1+
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2019-09-25 15:23:42 +02:00
Josef Bacik
aac0023c21 btrfs: move basic block_group definitions to their own header
This is prep work for moving all of the block group cache code into its
own file.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ minor comment updates ]
Signed-off-by: David Sterba <dsterba@suse.com>
2019-09-09 14:59:03 +02:00
Nikolay Borisov
330a582790 btrfs: Remove leftover of in-band dedupe
It's unlikely in-band dedupe is going to land so just remove any
leftovers - dedupe.h header as well as the 'dedupe' parameter to
btrfs_set_extent_delalloc.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2019-09-09 14:58:59 +02:00
Josef Bacik
867363429d btrfs: migrate the delalloc space stuff to it's own home
We have code for data and metadata reservations for delalloc.  There's
quite a bit of code here, and it's used in a lot of places so I've
separated it out to it's own file.  inode.c and file.c are already
pretty large, and this code is complicated enough to live in its own
space.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2019-07-04 17:26:17 +02:00
Qu Wenruo
30d40577e3 btrfs: reloc: Also queue orphan reloc tree for cleanup to avoid BUG_ON()
[BUG]
When a fs has orphan reloc tree along with unfinished balance:
  ...
        item 16 key (TREE_RELOC ROOT_ITEM FS_TREE) itemoff 12090 itemsize 439
                generation 12 root_dirid 256 bytenr 300400640 level 1 refs 0 <<<
                lastsnap 8 byte_limit 0 bytes_used 1359872 flags 0x0(none)
                uuid 7c48d938-33a3-4aae-ab19-6e5c9d406e46
        item 17 key (BALANCE TEMPORARY_ITEM 0) itemoff 11642 itemsize 448
                temporary item objectid BALANCE offset 0
                balance status flags 14

Then at mount time, we can hit the following kernel BUG_ON():
  BTRFS info (device dm-3): relocating block group 298844160 flags metadata|dup
  ------------[ cut here ]------------
  kernel BUG at fs/btrfs/relocation.c:1413!
  invalid opcode: 0000 [#1] PREEMPT SMP NOPTI
  CPU: 1 PID: 897 Comm: btrfs-balance Tainted: G           O      5.2.0-rc1-custom #15
  RIP: 0010:create_reloc_root+0x1eb/0x200 [btrfs]
  Call Trace:
   btrfs_init_reloc_root+0x96/0xb0 [btrfs]
   record_root_in_trans+0xb2/0xe0 [btrfs]
   btrfs_record_root_in_trans+0x55/0x70 [btrfs]
   select_reloc_root+0x7e/0x230 [btrfs]
   do_relocation+0xc4/0x620 [btrfs]
   relocate_tree_blocks+0x592/0x6a0 [btrfs]
   relocate_block_group+0x47b/0x5d0 [btrfs]
   btrfs_relocate_block_group+0x183/0x2f0 [btrfs]
   btrfs_relocate_chunk+0x4e/0xe0 [btrfs]
   btrfs_balance+0x864/0xfa0 [btrfs]
   balance_kthread+0x3b/0x50 [btrfs]
   kthread+0x123/0x140
   ret_from_fork+0x27/0x50

[CAUSE]
In btrfs, reloc trees are used to record swapped tree blocks during
balance.
Reloc tree either get merged (replace old tree blocks of its parent
subvolume) in next transaction if its ref is 1 (fresh).
Or is already merged and will be cleaned up if its ref is 0 (orphan).

After commit d2311e6985 ("btrfs: relocation: Delay reloc tree deletion
after merge_reloc_roots"), reloc tree cleanup is delayed until one block
group is balanced.

Since fresh reloc roots are recorded during merge, as long as there
is no power loss, those orphan reloc roots converted from fresh ones are
handled without problem.

However when power loss happens, orphan reloc roots can be recorded
on-disk, thus at next mount time, we will have orphan reloc roots from
on-disk data directly, and ignored by clean_dirty_subvols() routine.

Then when background balance starts to balance another block group, and
needs to create new reloc root for the same root, btrfs_insert_item()
returns -EEXIST, and trigger that BUG_ON().

[FIX]
For orphan reloc roots, also queue them to rc->dirty_subvol_roots, so
all reloc roots no matter orphan or not, can be cleaned up properly and
avoid above BUG_ON().

And to cooperate with above change, clean_dirty_subvols() will check if
the queued root is a reloc root or a subvol root.
For a subvol root, do the old work, and for a orphan reloc root, clean it
up.

Fixes: d2311e6985 ("btrfs: relocation: Delay reloc tree deletion after merge_reloc_roots")
CC: stable@vger.kernel.org # 5.1
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2019-05-28 18:54:10 +02:00
Qu Wenruo
ffd4bb2a19 btrfs: extent-tree: Use btrfs_ref to refactor btrfs_free_extent()
Similar to btrfs_inc_extent_ref(), use btrfs_ref to replace the long
parameter list and the confusing @owner parameter.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2019-04-29 19:02:49 +02:00
Qu Wenruo
82fa113fcc btrfs: extent-tree: Use btrfs_ref to refactor btrfs_inc_extent_ref()
Use the new btrfs_ref structure and replace parameter list to clean up
the usage of owner and level to distinguish the extent types.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2019-04-29 19:02:49 +02:00
David Sterba
7949f3392e btrfs: get fs_info from block group in lookup_free_space_inode
We can read fs_info from the block group cache structure and can drop it
from the parameters.

Signed-off-by: David Sterba <dsterba@suse.com>
2019-04-29 19:02:45 +02:00
Nikolay Borisov
f9756261c2 btrfs: Remove redundant inode argument from btrfs_add_ordered_sum
Ordered csums are keyed off of a btrfs_ordered_extent, which already has
a reference to the inode. This implies that an explicit inode argument
is redundant. So remove it.

Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2019-04-29 19:02:40 +02:00
Josef Bacik
ff612ba784 btrfs: fix panic during relocation after ENOSPC before writeback happens
We've been seeing the following sporadically throughout our fleet

panic: kernel BUG at fs/btrfs/relocation.c:4584!
netversion: 5.0-0
Backtrace:
 #0 [ffffc90003adb880] machine_kexec at ffffffff81041da8
 #1 [ffffc90003adb8c8] __crash_kexec at ffffffff8110396c
 #2 [ffffc90003adb988] crash_kexec at ffffffff811048ad
 #3 [ffffc90003adb9a0] oops_end at ffffffff8101c19a
 #4 [ffffc90003adb9c0] do_trap at ffffffff81019114
 #5 [ffffc90003adba00] do_error_trap at ffffffff810195d0
 #6 [ffffc90003adbab0] invalid_op at ffffffff81a00a9b
    [exception RIP: btrfs_reloc_cow_block+692]
    RIP: ffffffff8143b614  RSP: ffffc90003adbb68  RFLAGS: 00010246
    RAX: fffffffffffffff7  RBX: ffff8806b9c32000  RCX: ffff8806aad00690
    RDX: ffff880850b295e0  RSI: ffff8806b9c32000  RDI: ffff88084f205bd0
    RBP: ffff880849415000   R8: ffffc90003adbbe0   R9: ffff88085ac90000
    R10: ffff8805f7369140  R11: 0000000000000000  R12: ffff880850b295e0
    R13: ffff88084f205bd0  R14: 0000000000000000  R15: 0000000000000000
    ORIG_RAX: ffffffffffffffff  CS: 0010  SS: 0018
 #7 [ffffc90003adbbb0] __btrfs_cow_block at ffffffff813bf1cd
 #8 [ffffc90003adbc28] btrfs_cow_block at ffffffff813bf4b3
 #9 [ffffc90003adbc78] btrfs_search_slot at ffffffff813c2e6c

The way relocation moves data extents is by creating a reloc inode and
preallocating extents in this inode and then copying the data into these
preallocated extents.  Once we've done this for all of our extents,
we'll write out these dirty pages, which marks the extent written, and
goes into btrfs_reloc_cow_block().  From here we get our current
reloc_control, which _should_ match the reloc_control for the current
block group we're relocating.

However if we get an ENOSPC in this path at some point we'll bail out,
never initiating writeback on this inode.  Not a huge deal, unless we
happen to be doing relocation on a different block group, and this block
group is now rc->stage == UPDATE_DATA_PTRS.  This trips the BUG_ON() in
btrfs_reloc_cow_block(), because we expect to be done modifying the data
inode.  We are in fact done modifying the metadata for the data inode
we're currently using, but not the one from the failed block group, and
thus we BUG_ON().

(This happens when writeback finishes for extents from the previous
group, when we are at btrfs_finish_ordered_io() which updates the data
reloc tree (inode item, drops/adds extent items, etc).)

Fix this by writing out the reloc data inode always, and then breaking
out of the loop after that point to keep from tripping this BUG_ON()
later.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
[ add note from Filipe ]
Signed-off-by: David Sterba <dsterba@suse.com>
2019-04-29 19:02:24 +02:00
Qu Wenruo
10995c0491 btrfs: reloc: Fix NULL pointer dereference due to expanded reloc_root lifespan
Commit d2311e6985 ("btrfs: relocation: Delay reloc tree deletion after
merge_reloc_roots()") expands the life span of root->reloc_root.

This breaks certain checs of fs_info->reloc_ctl.  Before that commit, if
we have a root with valid reloc_root, then it's ensured to have
fs_info->reloc_ctl.

But now since reloc_root doesn't always mean a valid fs_info->reloc_ctl,
such check is unreliable and can cause the following NULL pointer
dereference:

  BUG: unable to handle kernel NULL pointer dereference at 00000000000005c1
  IP: btrfs_reloc_pre_snapshot+0x20/0x50 [btrfs]
  PGD 0 P4D 0
  Oops: 0000 [#1] SMP PTI
  CPU: 0 PID: 10379 Comm: snapperd Not tainted
  Call Trace:
   create_pending_snapshot+0xd7/0xfc0 [btrfs]
   create_pending_snapshots+0x8e/0xb0 [btrfs]
   btrfs_commit_transaction+0x2ac/0x8f0 [btrfs]
   btrfs_mksubvol+0x561/0x570 [btrfs]
   btrfs_ioctl_snap_create_transid+0x189/0x190 [btrfs]
   btrfs_ioctl_snap_create_v2+0x102/0x150 [btrfs]
   btrfs_ioctl+0x5c9/0x1e60 [btrfs]
   do_vfs_ioctl+0x90/0x5f0
   SyS_ioctl+0x74/0x80
   do_syscall_64+0x7b/0x150
   entry_SYSCALL_64_after_hwframe+0x3d/0xa2
  RIP: 0033:0x7fd7cdab8467

Fix it by explicitly checking fs_info->reloc_ctl other than using the
implied root->reloc_root.

Fixes: d2311e6985 ("btrfs: relocation: Delay reloc tree deletion after merge_reloc_roots")
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2019-04-29 19:02:22 +02:00
Qu Wenruo
43eb5f2975 btrfs: Introduce extent_io_tree::owner to distinguish different io_trees
Btrfs has the following different extent_io_trees used:

- fs_info::free_extents[2]
- btrfs_inode::io_tree - for both normal inodes and the btree inode
- btrfs_inode::io_failure_tree
- btrfs_transaction::dirty_pages
- btrfs_root::dirty_log_pages

If we want to trace changes in those trees, it will be pretty hard to
distinguish them.

Instead of using hard-to-read pointer address, this patch will introduce
a new member extent_io_tree::owner to track the owner.

This modification needs all the callers of extent_io_tree_init() to
accept a new parameter @owner.

This patch provides the basis for later trace events.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2019-04-29 19:02:18 +02:00
Qu Wenruo
c258d6e364 btrfs: Introduce fs_info to extent_io_tree
This patch will add a new member fs_info to extent_io_tree.

This provides the basis for later trace events to distinguish the output
between different btrfs filesystems. While this increases the size of
the structure, we want to know the source of the trace events and
passing the fs_info as an argument to all contexts is not possible.

The selftests are now allowed to set it to NULL as they don't use the
tracepoints.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2019-04-29 19:02:18 +02:00
Filipe Manana
cbca7d59fe Btrfs: add missing error handling after doing leaf/node binary search
The function map_private_extent_buffer() can return an -EINVAL error, and
it is called by generic_bin_search() which will return back the error. The
btrfs_bin_search() function in turn calls generic_bin_search() and the
key_search() function calls btrfs_bin_search(), so both can return the
-EINVAL error coming from the map_private_extent_buffer() function. Some
callers of these functions were ignoring that these functions can return
an error, so fix them to deal with error return values.

Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2019-02-25 14:19:23 +01:00
David Sterba
8bead25820 btrfs: open code now trivial btrfs_set_lock_blocking
btrfs_set_lock_blocking is now only a simple wrapper around
btrfs_set_lock_blocking_write. The name does not bring any semantic
value that could not be inferred from the new function so there's no
point keeping it.

Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: David Sterba <dsterba@suse.com>
2019-02-25 14:13:27 +01:00
Qu Wenruo
f616f5cd9d btrfs: qgroup: Use delayed subtree rescan for balance
Before this patch, qgroup code traces the whole subtree of subvolume and
reloc trees unconditionally.

This makes qgroup numbers consistent, but it could cause tons of
unnecessary extent tracing, which causes a lot of overhead.

However for subtree swap of balance, just swap both subtrees because
they contain the same contents and tree structure, so qgroup numbers
won't change.

It's the race window between subtree swap and transaction commit could
cause qgroup number change.

This patch will delay the qgroup subtree scan until COW happens for the
subtree root.

So if there is no other operations for the fs, balance won't cause extra
qgroup overhead. (best case scenario)
Depending on the workload, most of the subtree scan can still be
avoided.

Only for worst case scenario, it will fall back to old subtree swap
overhead. (scan all swapped subtrees)

[[Benchmark]]
Hardware:
	VM 4G vRAM, 8 vCPUs,
	disk is using 'unsafe' cache mode,
	backing device is SAMSUNG 850 evo SSD.
	Host has 16G ram.

Mkfs parameter:
	--nodesize 4K (To bump up tree size)

Initial subvolume contents:
	4G data copied from /usr and /lib.
	(With enough regular small files)

Snapshots:
	16 snapshots of the original subvolume.
	each snapshot has 3 random files modified.

balance parameter:
	-m

So the content should be pretty similar to a real world root fs layout.

And after file system population, there is no other activity, so it
should be the best case scenario.

                     | v4.20-rc1            | w/ patchset    | diff
-----------------------------------------------------------------------
relocated extents    | 22615                | 22457          | -0.1%
qgroup dirty extents | 163457               | 121606         | -25.6%
time (sys)           | 22.884s              | 18.842s        | -17.6%
time (real)          | 27.724s              | 22.884s        | -17.5%

Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2019-02-25 14:13:26 +01:00
Qu Wenruo
370a11b811 btrfs: qgroup: Introduce per-root swapped blocks infrastructure
To allow delayed subtree swap rescan, btrfs needs to record per-root
information about which tree blocks get swapped.  This patch introduces
the required infrastructure.

The designed workflow will be:

1) Record the subtree root block that gets swapped.

   During subtree swap:
   O = Old tree blocks
   N = New tree blocks
         reloc tree                         subvolume tree X
            Root                               Root
           /    \                             /    \
         NA     OB                          OA      OB
       /  |     |  \                      /  |      |  \
     NC  ND     OE  OF                   OC  OD     OE  OF

  In this case, NA and OA are going to be swapped, record (NA, OA) into
  subvolume tree X.

2) After subtree swap.
         reloc tree                         subvolume tree X
            Root                               Root
           /    \                             /    \
         OA     OB                          NA      OB
       /  |     |  \                      /  |      |  \
     OC  OD     OE  OF                   NC  ND     OE  OF

3a) COW happens for OB
    If we are going to COW tree block OB, we check OB's bytenr against
    tree X's swapped_blocks structure.
    If it doesn't fit any, nothing will happen.

3b) COW happens for NA
    Check NA's bytenr against tree X's swapped_blocks, and get a hit.
    Then we do subtree scan on both subtrees OA and NA.
    Resulting 6 tree blocks to be scanned (OA, OC, OD, NA, NC, ND).

    Then no matter what we do to subvolume tree X, qgroup numbers will
    still be correct.
    Then NA's record gets removed from X's swapped_blocks.

4)  Transaction commit
    Any record in X's swapped_blocks gets removed, since there is no
    modification to swapped subtrees, no need to trigger heavy qgroup
    subtree rescan for them.

This will introduce 128 bytes overhead for each btrfs_root even qgroup
is not enabled. This is to reduce memory allocations and potential
failures.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2019-02-25 14:13:26 +01:00
Qu Wenruo
d2311e6985 btrfs: relocation: Delay reloc tree deletion after merge_reloc_roots
Relocation code will drop btrfs_root::reloc_root as soon as
merge_reloc_root() finishes.

However later qgroup code will need to access btrfs_root::reloc_root
after merge_reloc_root() for delayed subtree rescan.

So alter the timming of resetting btrfs_root:::reloc_root, make it
happens after transaction commit.

With this patch, we will introduce a new btrfs_root::state,
BTRFS_ROOT_DEAD_RELOC_TREE, to info part of btrfs_root::reloc_tree user
that although btrfs_root::reloc_tree is still non-NULL, but still it's
not used any more.

The lifespan of btrfs_root::reloc tree will become:
          Old behavior            |              New
------------------------------------------------------------------------
btrfs_init_reloc_root()      ---  | btrfs_init_reloc_root()      ---
  set reloc_root              |   |   set reloc_root              |
                              |   |                               |
                              |   |                               |
merge_reloc_root()            |   | merge_reloc_root()            |
|- btrfs_update_reloc_root() ---  | |- btrfs_update_reloc_root() -+-
     clear btrfs_root::reloc_root |      set ROOT_DEAD_RELOC_TREE |
                                  |      record root into dirty   |
                                  |      roots rbtree             |
                                  |                               |
                                  | reloc_block_group() Or        |
                                  | btrfs_recover_relocation()    |
                                  | | After transaction commit    |
                                  | |- clean_dirty_subvols()     ---
                                  |     clear btrfs_root::reloc_root

During ROOT_DEAD_RELOC_TREE set lifespan, the only user of
btrfs_root::reloc_tree should be qgroup.

Since reloc root needs a longer life-span, this patch will also delay
btrfs_drop_snapshot() call.
Now btrfs_drop_snapshot() is called in clean_dirty_subvols().

This patch will increase the size of btrfs_root by 16 bytes.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2019-02-25 14:13:25 +01:00
Julia Lawall
9cf10cc195 Btrfs: drop useless LIST_HEAD in merge_reloc_root
Drop LIST_HEAD where the variable it declares is never used.

The uses were removed in 3fd0a5585e ("Btrfs: Metadata ENOSPC
handling for balance"), but not the declaration.

The semantic patch that fixes this problem is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@@
identifier x;
@@
- LIST_HEAD(x);
  ... when != x
// </smpl>

Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2019-02-25 14:13:15 +01:00
Andrea Gelmini
52042d8e82 btrfs: Fix typos in comments and strings
The typos accumulate over time so once in a while time they get fixed in
a large patch.

Signed-off-by: Andrea Gelmini <andrea.gelmini@gelma.net>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2018-12-17 14:51:50 +01:00
Anand Jain
f89e09cf45 btrfs: add helper to describe block group flags
Factor out helper that describes block group flags from
describe_relocation. The result will not be longer than the given size.

Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ add comments ]
Signed-off-by: David Sterba <dsterba@suse.com>
2018-12-17 14:51:39 +01:00
Omar Sandoval
eede2bf34f Btrfs: prevent ioctls from interfering with a swap file
A later patch will implement swap file support for Btrfs, but before we
do that, we need to make sure that the various Btrfs ioctls cannot
change a swap file.

When a swap file is active, we must make sure that the extents of the
file are not moved and that they don't become shared. That means that
the following are not safe:

- chattr +c (enable compression)
- reflink
- dedupe
- snapshot
- defrag

Don't allow those to happen on an active swap file.

Additionally, balance, resize, device remove, and device replace are
also unsafe if they affect an active swapfile. Add a red-black tree of
block groups and devices which contain an active swapfile. Relocation
checks each block group against this tree and skips it or errors out for
balance or resize, respectively. Device remove and device replace check
the tree for the device they will operate on.

Note that we don't have to worry about chattr -C (disable nocow), which
we ignore for non-empty files, because an active swapfile must be
non-empty and can't be truncated. We also don't have to worry about
autodefrag because it's only done on COW files. Truncate and fallocate
are already taken care of by the generic code. Device add doesn't do
relocation so it's not an issue, either.

Signed-off-by: Omar Sandoval <osandov@fb.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2018-12-17 14:51:29 +01:00
Pan Bian
42a657f576 btrfs: relocation: set trans to be NULL after ending transaction
The function relocate_block_group calls btrfs_end_transaction to release
trans when update_backref_cache returns 1, and then continues the loop
body. If btrfs_block_rsv_refill fails this time, it will jump out the
loop and the freed trans will be accessed. This may result in a
use-after-free bug. The patch assigns NULL to trans after trans is
released so that it will not be accessed.

Fixes: 0647bf564f ("Btrfs: improve forever loop when doing balance relocation")
CC: stable@vger.kernel.org # 4.4+
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Pan Bian <bianpan2016@163.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2018-11-23 13:47:46 +01:00
Qu Wenruo
06bbf67244 btrfs: relocation: Remove redundant tree level check
Commit 581c176041 ("btrfs: Validate child tree block's level and first
key") has made tree block level check mandatory.

So if tree block level doesn't match, we won't get a valid extent
buffer.  The extra WARN_ON() check can be removed completely.

Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2018-10-15 17:23:40 +02:00
Qu Wenruo
98ff7b94e4 btrfs: relocation: Cleanup while loop using rbtree_postorder_for_each_entry_safe
And add one line comment explaining what we're doing for each loop.

Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2018-10-15 17:23:40 +02:00
Qu Wenruo
3d0174f78e btrfs: qgroup: Only trace data extents in leaves if we're relocating data block group
For qgroup_trace_extent_swap(), if we find one leaf that needs to be
traced, we will also iterate all file extents and trace them.

This is OK if we're relocating data block groups, but if we're
relocating metadata block groups, balance code itself has ensured that
both subtree of file tree and reloc tree contain the same contents.

That's to say, if we're relocating metadata block groups, all file
extents in reloc and file tree should match, thus no need to trace them.
This should reduce the total number of dirty extents processed in metadata
block group balance.

[[Benchmark]] (with all previous enhancement)
Hardware:
	VM 4G vRAM, 8 vCPUs,
	disk is using 'unsafe' cache mode,
	backing device is SAMSUNG 850 evo SSD.
	Host has 16G ram.

Mkfs parameter:
	--nodesize 4K (To bump up tree size)

Initial subvolume contents:
	4G data copied from /usr and /lib.
	(With enough regular small files)

Snapshots:
	16 snapshots of the original subvolume.
	each snapshot has 3 random files modified.

balance parameter:
	-m

So the content should be pretty similar to a real world root fs layout.

                     | v4.19-rc1    | w/ patchset    | diff (*)
---------------------------------------------------------------
relocated extents    | 22929        | 22851          | -0.3%
qgroup dirty extents | 227757       | 140886         | -38.1%
time (sys)           | 65.253s      | 37.464s        | -42.6%
time (real)          | 74.032s      | 44.722s        | -39.6%

Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2018-10-15 17:23:36 +02:00
Qu Wenruo
5f527822be btrfs: qgroup: Use generation-aware subtree swap to mark dirty extents
Before this patch, with quota enabled during balance, we need to mark
the whole subtree dirty for quota.

E.g.
OO = Old tree blocks (from file tree)
NN = New tree blocks (from reloc tree)

        File tree (src)		          Reloc tree (dst)
            OO (a)                              NN (a)
           /  \                                /  \
     (b) OO    OO (c)                    (b) NN    NN (c)
        /  \  /  \                          /  \  /  \
       OO  OO OO OO (d)                    OO  OO OO NN (d)

For old balance + quota case, quota will mark the whole src and dst tree
dirty, including all the 3 old tree blocks in reloc tree.

It's doable for small file tree or new tree blocks are all located at
lower level.

But for large file tree or new tree blocks are all located at higher
level, this will lead to mark the whole tree dirty, and be unbelievably
slow.

This patch will change how we handle such balance with quota enabled
case.

Now we will search from (b) and (c) for any new tree blocks whose
generation is equal to @last_snapshot, and only mark them dirty.

In above case, we only need to trace tree blocks NN(b), NN(c) and NN(d).
(NN(a) will be traced when COW happens for nodeptr modification).  And
also for tree blocks OO(b), OO(c), OO(d). (OO(a) will be traced when COW
happens for nodeptr modification.)

For above case, we could skip 3 tree blocks, but for larger tree, we can
skip tons of unmodified tree blocks, and hugely speed up balance.

This patch will introduce a new function,
btrfs_qgroup_trace_subtree_swap(), which will do the following main
work:

1) Read out real root eb
   And setup basic dst_path for later calls
2) Call qgroup_trace_new_subtree_blocks()
   To trace all new tree blocks in reloc tree and their counter
   parts in the file tree.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2018-10-15 17:23:36 +02:00
Qu Wenruo
fa6ac71524 btrfs: relocation: Add basic extent backref related comments for build_backref_tree
fs/btrfs/relocation.c:build_backref_tree() is some code from 2009 era,
although it works pretty fine, it's not that easy to understand.
Especially combined with the complex btrfs backref format.

This patch adds some basic comment for the backref build part of the
code, making it less hard to read, at least for backref searching part.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2018-10-15 17:23:35 +02:00
Qu Wenruo
65c6e82bec btrfs: Handle owner mismatch gracefully when walking up tree
[BUG]
When mounting certain crafted image, btrfs will trigger kernel BUG_ON()
when trying to recover balance:

  kernel BUG at fs/btrfs/extent-tree.c:8956!
  invalid opcode: 0000 [#1] PREEMPT SMP NOPTI
  CPU: 1 PID: 662 Comm: mount Not tainted 4.18.0-rc1-custom+ #10
  RIP: 0010:walk_up_proc+0x336/0x480 [btrfs]
  RSP: 0018:ffffb53540c9b890 EFLAGS: 00010202
  Call Trace:
   walk_up_tree+0x172/0x1f0 [btrfs]
   btrfs_drop_snapshot+0x3a4/0x830 [btrfs]
   merge_reloc_roots+0xe1/0x1d0 [btrfs]
   btrfs_recover_relocation+0x3ea/0x420 [btrfs]
   open_ctree+0x1af3/0x1dd0 [btrfs]
   btrfs_mount_root+0x66b/0x740 [btrfs]
   mount_fs+0x3b/0x16a
   vfs_kern_mount.part.9+0x54/0x140
   btrfs_mount+0x16d/0x890 [btrfs]
   mount_fs+0x3b/0x16a
   vfs_kern_mount.part.9+0x54/0x140
   do_mount+0x1fd/0xda0
   ksys_mount+0xba/0xd0
   __x64_sys_mount+0x21/0x30
   do_syscall_64+0x60/0x210
   entry_SYSCALL_64_after_hwframe+0x49/0xbe

[CAUSE]
Extent tree corruption.  In this particular case, reloc tree root's
owner is DATA_RELOC_TREE (should be TREE_RELOC), thus its backref is
corrupted and we failed the owner check in walk_up_tree().

[FIX]
It's pretty hard to take care of every extent tree corruption, but at
least we can remove such BUG_ON() and exit more gracefully.

And since in this particular image, DATA_RELOC_TREE and TREE_RELOC share
the same root (which is obviously invalid), we needs to make
__del_reloc_root() more robust to detect such invalid sharing to avoid
possible NULL dereference as root->node can be NULL in this case.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=200411
Reported-by: Xu Wen <wen.xu@gatech.edu>
CC: stable@vger.kernel.org # 4.4+
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2018-10-15 17:23:27 +02:00
Misono Tomohiro
4fd786e6c3 btrfs: Remove 'objectid' member from struct btrfs_root
There are two members in struct btrfs_root which indicate root's
objectid: objectid and root_key.objectid.

They are both set to the same value in __setup_root():

  static void __setup_root(struct btrfs_root *root,
                           struct btrfs_fs_info *fs_info,
                           u64 objectid)
  {
    ...
    root->objectid = objectid;
    ...
    root->root_key.objectid = objecitd;
    ...
  }

and not changed to other value after initialization.

grep in btrfs directory shows both are used in many places:
  $ grep -rI "root->root_key.objectid" | wc -l
  133
  $ grep -rI "root->objectid" | wc -l
  55
 (4.17, inc. some noise)

It is confusing to have two similar variable names and it seems
that there is no rule about which should be used in a certain case.

Since ->root_key itself is needed for tree reloc tree, let's remove
'objecitd' member and unify code to use ->root_key.objectid in all places.

Signed-off-by: Misono Tomohiro <misono.tomohiro@jp.fujitsu.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2018-10-15 17:23:25 +02:00
Lu Fengqi
3a58417486 btrfs: switch update_size to bool in btrfs_block_rsv_migrate and btrfs_rsv_add_bytes
Using true and false here is closer to the expected semantic than using
0 and 1.  No functional change.

Signed-off-by: Lu Fengqi <lufq.fnst@cn.fujitsu.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2018-10-15 17:23:25 +02:00
Al Viro
2e19f1f9d3 btrfs: btrfs_iget never returns an is_bad_inode inode
Just get rid of pointless checks.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2018-08-06 13:13:02 +02:00
Lu Fengqi
deb4062743 btrfs: qgroup: Drop root parameter from btrfs_qgroup_trace_subtree
The fs_info can be fetched from the transaction handle directly.

Signed-off-by: Lu Fengqi <lufq.fnst@cn.fujitsu.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2018-08-06 13:12:52 +02:00
Qu Wenruo
389305b2aa btrfs: relocation: Only remove reloc rb_trees if reloc control has been initialized
Invalid reloc tree can cause kernel NULL pointer dereference when btrfs
does some cleanup of the reloc roots.

It turns out that fs_info::reloc_ctl can be NULL in
btrfs_recover_relocation() as we allocate relocation control after all
reloc roots have been verified.
So when we hit: note, we haven't called set_reloc_control() thus
fs_info::reloc_ctl is still NULL.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=199833
Reported-by: Xu Wen <wen.xu@gatech.edu>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Tested-by: Gu Jinxiang <gujx@cn.fujitsu.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2018-08-06 13:12:42 +02:00
David Sterba
6d8ff4e458 btrfs: annotate unlikely branches after V0 extent type removal
The v0 extent type checks are the right case for the unlikely
annotations as we don't expect to ever see them, so let's give the
compiler some hint.

Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2018-08-06 13:12:41 +02:00
Nikolay Borisov
ba3c2b196b btrfs: Add graceful handling of V0 extents
Following the removal of the v0 handling code let's be courteous and
print an error message when such extents are handled. In the cases
where we have a transaction just abort it, otherwise just call
btrfs_handle_fs_error. Both cases result in the FS being re-mounted RO.

In case the error handling would be too intrusive, leave the BUG_ON in
place, like extent_data_ref_count, other proper handling would catch
that earlier.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2018-08-06 13:12:41 +02:00
Nikolay Borisov
a79865c680 btrfs: Remove V0 extent support
The v0 compat code was introduced in commit 5d4f98a28c
("Btrfs: Mixed back reference  (FORWARD ROLLING FORMAT CHANGE)") 9
years ago, which was merged in 2.6.31. This means that the code is
there to support filesystems which are _VERY_ old and if you are using
btrfs on such an old kernel, you have much bigger problems. This coupled
with the fact that no one is likely testing/maintining this code likely
means it has bugs lurking. All things considered I think 43 kernel
releases later it's high time this remnant of the past got removed.

This patch removes all code wrapped in #ifdefs but leaves the BUG_ONs in case
we have a v0 with no support intact as a sort of safety-net.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2018-08-06 13:12:41 +02:00
Su Yue
af431dcb24 btrfs: return EUCLEAN if extent_inline_ref type is invalid
If type of extent_inline_ref found is not expected, filesystem may have
been corrupted, should return EUCLEAN instead of EINVAL.

Signed-off-by: Su Yue <suy.fnst@cn.fujitsu.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2018-08-06 13:12:40 +02:00
Nikolay Borisov
43a7e99db6 btrfs: Remove fs_info from btrfs_force_chunk_alloc
It can be referenced from the passed transaction handle.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2018-08-06 13:12:38 +02:00
Nikolay Borisov
c83488afc5 btrfs: Remove fs_info from btrfs_inc_block_group_ro
It can be referenced from the passed bg cache.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2018-08-06 13:12:37 +02:00
Anand Jain
b78e2b78a8 btrfs: fix describe_relocation when printing unknown flags
Looks like the original idea was to print the hex of the flags which is
not coded with their flag name. So use the current buf pointer bp
instead of buf.

Reaching the uknown flags should never happen, it's there just in case.

Fixes: ebce0e01b9 ("btrfs: make block group flags in balance printks human-readable")
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2018-05-28 18:24:11 +02:00