Btrfs uses 2 different methods to reseve metadata qgroup space.

1) Reserve at btrfs_start_transaction() time
   This is quite straightforward, caller will use the trans handler
   allocated to modify b-trees.

   In this case, reserved metadata should be kept until qgroup numbers
   are updated.

2) Reserve by using block_rsv first, and later btrfs_join_transaction()
   This is more complicated, caller will reserve space using block_rsv
   first, and then later call btrfs_join_transaction() to get a trans
   handle.

   In this case, before we modify trees, the reserved space can be
   modified on demand, and after btrfs_join_transaction(), such reserved
   space should also be kept until qgroup numbers are updated.

Since these two types behave differently, split the original "META"
reservation type into 2 sub-types:

  META_PERTRANS:
    For above case 1)

  META_PREALLOC:
    For reservations that happened before btrfs_join_transaction() of
    case 2)

NOTE: This patch will only convert existing qgroup meta reservation
callers according to its situation, not ensuring all callers are at
correct timing.
Such fix will be added in later patches.
Signed-off-by: Qu Wenruo <wqu@suse.com>
[ update comments ]
Signed-off-by: David Sterba <dsterba@suse.com>

So qgroup is switched to new separate types reservation system.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

When modifying qgroup relationship, for qgroup which only owns exclusive
extents, we will go through quick update path.

In this path, we will add/subtract exclusive and reference number for
parent qgroup, since the source (child) qgroup only has exclusive
extents, destination (parent) qgroup will also own or lose those extents
exclusively.

The same should be the same for reservation, since later reservation
adding/releasing will also affect parent qgroup, without the reservation
carried from child, parent will underflow reservation or have dead
reservation which will never be freed.

However original code doesn't do the same thing for reservation.
It handles qgroup reservation quite differently:

It removes qgroup reservation, as it's allocating space from the
reserved qgroup for relationship adding.
But does nothing for qgroup reservation if we're removing a qgroup
relationship.

According to the original code, it looks just like because we're adding
qgroup->rfer, the code assumes we're writing new data, so it's follows
the normal write routine, by reducing qgroup->reserved and adding
qgroup->rfer/excl.

This old behavior is wrong, and should be fixed to follow the same
excl/rfer behavior.

Just fix it by using the correct behavior described above.

Fixes: 31193213 ("Btrfs: qgroup: Introduce a may_use to account space_info->bytes_may_use.")
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

Since most callers of qgroup_reserve() are already defined by type,
converting qgroup_reserve() is quite an easy work.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

Introduce helpers to:

1) Get total reserved space
   For limit calculation
2) Add/release reserved space for given type
   With underflow detection and warning
3) Add/release reserved space according to child qgroup
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

Instead of single qgroup->reserved, use a new structure btrfs_qgroup_rsv
to store different types of reservation.

This patch only updates the header needed to compile.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

btrfs_orphan_add() has had this case commented out since it was first
introduced in commit d68fc57b ("Btrfs: Metadata reservation for
orphan inodes"). Most of the orphan cleanup code has been rewritten
since then, so it's safe to say that this code isn't needed.
Signed-off-by: Omar Sandoval <osandov@fb.com>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
[ switch to bool ]
Signed-off-by: David Sterba <dsterba@suse.com>

Signed-off-by: Tomohiro Misono <misono.tomohiro@jp.fujitsu.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

Any time the first block group of a new type is created, we add a new
kobject to sysfs to hold the attributes for that type.  Kobject-internal
allocations always use GFP_KERNEL, making them prone to fs-reclaim races.
While it appears as if this can occur any time a block group is created,
the only times the first block group of a new type can be created in
memory is at mount and when we create the first new block group during
raid conversion.

This patch adds a new list to track pending kobject additions and then
handles them after we do chunk relocation.  Between relocating the
target chunk (or forcing allocation of a new chunk in the case of data)
and removing the old chunk, we're in a safe place for fs-reclaim to
occur.  We're holding the volume mutex, which is already held across
page faults, and the delete_unused_bgs_mutex, which will only stall
the cleaner thread.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

Since commit 2be12ef7 (btrfs: Separate space_info create/update), we've
separated out the creation and updating of the space info structures.
That commit was a straightforward refactoring of the two parts of
update_space_info, but we can go a step further.  Since commits
c59021f8 (Btrfs: fix OOPS of empty filesystem after balance) and
b742bb82 (Btrfs: Link block groups of different raid types), we know
that the space_info structures will be created at mount and there will
only ever be, at most, three of them.

This patch cleans out the create_space_info calls after __find_space_info
returns NULL since __find_space_info *can't* return NULL.

The initial cause for reviewing this was the kobject_add calls from
create_space_info occuring in sites where fs-reclaim wasn't allowed.  Now
we are certain they occur only early in the mount process and are safe.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

Rebuild on missing device is as same as recover, after it's done, rbio
has data which is consistent with on-disk data, so it can be cached to
avoid further reads.
Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: Liu Bo <bo.liu@linux.alibaba.com>
Signed-off-by: David Sterba <dsterba@suse.com>

While running btrfs/011, I hit the following lockdep splat.

This is the important bit:
   pcpu_alloc+0x1ac/0x5e0
   __percpu_counter_init+0x4e/0xb0
   btrfs_init_fs_root+0x99/0x1c0 [btrfs]
   btrfs_get_fs_root.part.54+0x5b/0x150 [btrfs]
   resolve_indirect_refs+0x130/0x830 [btrfs]
   find_parent_nodes+0x69e/0xff0 [btrfs]
   btrfs_find_all_roots_safe+0xa0/0x110 [btrfs]
   btrfs_find_all_roots+0x50/0x70 [btrfs]
   btrfs_qgroup_prepare_account_extents+0x53/0x90 [btrfs]
   btrfs_commit_transaction+0x3ce/0x9b0 [btrfs]

The percpu_counter_init call in btrfs_alloc_subvolume_writers
uses GFP_KERNEL, which we can't do during transaction commit.

This switches it to GFP_NOFS.

========================================================
WARNING: possible irq lock inversion dependency detected
4.12.14-kvmsmall #8 Tainted: G        W
--------------------------------------------------------
kswapd0/50 just changed the state of lock:
 (&delayed_node->mutex){+.+.-.}, at: [<ffffffffc06994fa>] __btrfs_release_delayed_node+0x3a/0x1f0 [btrfs]
but this lock took another, RECLAIM_FS-unsafe lock in the past:
 (pcpu_alloc_mutex){+.+.+.}

and interrupts could create inverse lock ordering between them.

other info that might help us debug this:
Chain exists of:
  &delayed_node->mutex --> &found->groups_sem --> pcpu_alloc_mutex

 Possible interrupt unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(pcpu_alloc_mutex);
                               local_irq_disable();
                               lock(&delayed_node->mutex);
                               lock(&found->groups_sem);
  <Interrupt>
    lock(&delayed_node->mutex);

 *** DEADLOCK ***

2 locks held by kswapd0/50:
 #0:  (shrinker_rwsem){++++..}, at: [<ffffffff811dc11f>] shrink_slab+0x7f/0x5b0
 #1:  (&type->s_umount_key#30){+++++.}, at: [<ffffffff8126dec6>] trylock_super+0x16/0x50

the shortest dependencies between 2nd lock and 1st lock:
   -> (pcpu_alloc_mutex){+.+.+.} ops: 4904 {
      HARDIRQ-ON-W at:
                          __mutex_lock+0x4e/0x8c0
                          pcpu_alloc+0x1ac/0x5e0
                          alloc_kmem_cache_cpus.isra.70+0x25/0xa0
                          __do_tune_cpucache+0x2c/0x220
                          do_tune_cpucache+0x26/0xc0
                          enable_cpucache+0x6d/0xf0
                          kmem_cache_init_late+0x42/0x75
                          start_kernel+0x343/0x4cb
                          x86_64_start_kernel+0x127/0x134
                          secondary_startup_64+0xa5/0xb0
      SOFTIRQ-ON-W at:
                          __mutex_lock+0x4e/0x8c0
                          pcpu_alloc+0x1ac/0x5e0
                          alloc_kmem_cache_cpus.isra.70+0x25/0xa0
                          __do_tune_cpucache+0x2c/0x220
                          do_tune_cpucache+0x26/0xc0
                          enable_cpucache+0x6d/0xf0
                          kmem_cache_init_late+0x42/0x75
                          start_kernel+0x343/0x4cb
                          x86_64_start_kernel+0x127/0x134
                          secondary_startup_64+0xa5/0xb0
      RECLAIM_FS-ON-W at:
                             __kmalloc+0x47/0x310
                             pcpu_extend_area_map+0x2b/0xc0
                             pcpu_alloc+0x3ec/0x5e0
                             alloc_kmem_cache_cpus.isra.70+0x25/0xa0
                             __do_tune_cpucache+0x2c/0x220
                             do_tune_cpucache+0x26/0xc0
                             enable_cpucache+0x6d/0xf0
                             __kmem_cache_create+0x1bf/0x390
                             create_cache+0xba/0x1b0
                             kmem_cache_create+0x1f8/0x2b0
                             ksm_init+0x6f/0x19d
                             do_one_initcall+0x50/0x1b0
                             kernel_init_freeable+0x201/0x289
                             kernel_init+0xa/0x100
                             ret_from_fork+0x3a/0x50
      INITIAL USE at:
                         __mutex_lock+0x4e/0x8c0
                         pcpu_alloc+0x1ac/0x5e0
                         alloc_kmem_cache_cpus.isra.70+0x25/0xa0
                         setup_cpu_cache+0x2f/0x1f0
                         __kmem_cache_create+0x1bf/0x390
                         create_boot_cache+0x8b/0xb1
                         kmem_cache_init+0xa1/0x19e
                         start_kernel+0x270/0x4cb
                         x86_64_start_kernel+0x127/0x134
                         secondary_startup_64+0xa5/0xb0
    }
    ... key      at: [<ffffffff821d8e70>] pcpu_alloc_mutex+0x70/0xa0
    ... acquired at:
   pcpu_alloc+0x1ac/0x5e0
   __percpu_counter_init+0x4e/0xb0
   btrfs_init_fs_root+0x99/0x1c0 [btrfs]
   btrfs_get_fs_root.part.54+0x5b/0x150 [btrfs]
   resolve_indirect_refs+0x130/0x830 [btrfs]
   find_parent_nodes+0x69e/0xff0 [btrfs]
   btrfs_find_all_roots_safe+0xa0/0x110 [btrfs]
   btrfs_find_all_roots+0x50/0x70 [btrfs]
   btrfs_qgroup_prepare_account_extents+0x53/0x90 [btrfs]
   btrfs_commit_transaction+0x3ce/0x9b0 [btrfs]
   transaction_kthread+0x176/0x1b0 [btrfs]
   kthread+0x102/0x140
   ret_from_fork+0x3a/0x50

  -> (&fs_info->commit_root_sem){++++..} ops: 1566382 {
     HARDIRQ-ON-W at:
                        down_write+0x3e/0xa0
                        cache_block_group+0x287/0x420 [btrfs]
                        find_free_extent+0x106c/0x12d0 [btrfs]
                        btrfs_reserve_extent+0xd8/0x170 [btrfs]
                        cow_file_range.isra.66+0x133/0x470 [btrfs]
                        run_delalloc_range+0x121/0x410 [btrfs]
                        writepage_delalloc.isra.50+0xfe/0x180 [btrfs]
                        __extent_writepage+0x19a/0x360 [btrfs]
                        extent_write_cache_pages.constprop.56+0x249/0x3e0 [btrfs]
                        extent_writepages+0x4d/0x60 [btrfs]
                        do_writepages+0x1a/0x70
                        __filemap_fdatawrite_range+0xa7/0xe0
                        btrfs_rename+0x5ee/0xdb0 [btrfs]
                        vfs_rename+0x52a/0x7e0
                        SyS_rename+0x351/0x3b0
                        do_syscall_64+0x79/0x1e0
                        entry_SYSCALL_64_after_hwframe+0x42/0xb7
     HARDIRQ-ON-R at:
                        down_read+0x35/0x90
                        caching_thread+0x57/0x560 [btrfs]
                        normal_work_helper+0x1c0/0x5e0 [btrfs]
                        process_one_work+0x1e0/0x5c0
                        worker_thread+0x44/0x390
                        kthread+0x102/0x140
                        ret_from_fork+0x3a/0x50
     SOFTIRQ-ON-W at:
                        down_write+0x3e/0xa0
                        cache_block_group+0x287/0x420 [btrfs]
                        find_free_extent+0x106c/0x12d0 [btrfs]
                        btrfs_reserve_extent+0xd8/0x170 [btrfs]
                        cow_file_range.isra.66+0x133/0x470 [btrfs]
                        run_delalloc_range+0x121/0x410 [btrfs]
                        writepage_delalloc.isra.50+0xfe/0x180 [btrfs]
                        __extent_writepage+0x19a/0x360 [btrfs]
                        extent_write_cache_pages.constprop.56+0x249/0x3e0 [btrfs]
                        extent_writepages+0x4d/0x60 [btrfs]
                        do_writepages+0x1a/0x70
                        __filemap_fdatawrite_range+0xa7/0xe0
                        btrfs_rename+0x5ee/0xdb0 [btrfs]
                        vfs_rename+0x52a/0x7e0
                        SyS_rename+0x351/0x3b0
                        do_syscall_64+0x79/0x1e0
                        entry_SYSCALL_64_after_hwframe+0x42/0xb7
     SOFTIRQ-ON-R at:
                        down_read+0x35/0x90
                        caching_thread+0x57/0x560 [btrfs]
                        normal_work_helper+0x1c0/0x5e0 [btrfs]
                        process_one_work+0x1e0/0x5c0
                        worker_thread+0x44/0x390
                        kthread+0x102/0x140
                        ret_from_fork+0x3a/0x50
     INITIAL USE at:
                       down_write+0x3e/0xa0
                       cache_block_group+0x287/0x420 [btrfs]
                       find_free_extent+0x106c/0x12d0 [btrfs]
                       btrfs_reserve_extent+0xd8/0x170 [btrfs]
                       cow_file_range.isra.66+0x133/0x470 [btrfs]
                       run_delalloc_range+0x121/0x410 [btrfs]
                       writepage_delalloc.isra.50+0xfe/0x180 [btrfs]
                       __extent_writepage+0x19a/0x360 [btrfs]
                       extent_write_cache_pages.constprop.56+0x249/0x3e0 [btrfs]
                       extent_writepages+0x4d/0x60 [btrfs]
                       do_writepages+0x1a/0x70
                       __filemap_fdatawrite_range+0xa7/0xe0
                       btrfs_rename+0x5ee/0xdb0 [btrfs]
                       vfs_rename+0x52a/0x7e0
                       SyS_rename+0x351/0x3b0
                       do_syscall_64+0x79/0x1e0
                       entry_SYSCALL_64_after_hwframe+0x42/0xb7
   }
   ... key      at: [<ffffffffc0729578>] __key.61970+0x0/0xfffffffffff9aa88 [btrfs]
   ... acquired at:
   cache_block_group+0x287/0x420 [btrfs]
   find_free_extent+0x106c/0x12d0 [btrfs]
   btrfs_reserve_extent+0xd8/0x170 [btrfs]
   btrfs_alloc_tree_block+0x12f/0x4c0 [btrfs]
   btrfs_create_tree+0xbb/0x2a0 [btrfs]
   btrfs_create_uuid_tree+0x37/0x140 [btrfs]
   open_ctree+0x23c0/0x2660 [btrfs]
   btrfs_mount+0xd36/0xf90 [btrfs]
   mount_fs+0x3a/0x160
   vfs_kern_mount+0x66/0x150
   btrfs_mount+0x18c/0xf90 [btrfs]
   mount_fs+0x3a/0x160
   vfs_kern_mount+0x66/0x150
   do_mount+0x1c1/0xcc0
   SyS_mount+0x7e/0xd0
   do_syscall_64+0x79/0x1e0
   entry_SYSCALL_64_after_hwframe+0x42/0xb7

 -> (&found->groups_sem){++++..} ops: 2134587 {
    HARDIRQ-ON-W at:
                      down_write+0x3e/0xa0
                      __link_block_group+0x34/0x130 [btrfs]
                      btrfs_read_block_groups+0x33d/0x7b0 [btrfs]
                      open_ctree+0x2054/0x2660 [btrfs]
                      btrfs_mount+0xd36/0xf90 [btrfs]
                      mount_fs+0x3a/0x160
                      vfs_kern_mount+0x66/0x150
                      btrfs_mount+0x18c/0xf90 [btrfs]
                      mount_fs+0x3a/0x160
                      vfs_kern_mount+0x66/0x150
                      do_mount+0x1c1/0xcc0
                      SyS_mount+0x7e/0xd0
                      do_syscall_64+0x79/0x1e0
                      entry_SYSCALL_64_after_hwframe+0x42/0xb7
    HARDIRQ-ON-R at:
                      down_read+0x35/0x90
                      btrfs_calc_num_tolerated_disk_barrier_failures+0x113/0x1f0 [btrfs]
                      open_ctree+0x207b/0x2660 [btrfs]
                      btrfs_mount+0xd36/0xf90 [btrfs]
                      mount_fs+0x3a/0x160
                      vfs_kern_mount+0x66/0x150
                      btrfs_mount+0x18c/0xf90 [btrfs]
                      mount_fs+0x3a/0x160
                      vfs_kern_mount+0x66/0x150
                      do_mount+0x1c1/0xcc0
                      SyS_mount+0x7e/0xd0
                      do_syscall_64+0x79/0x1e0
                      entry_SYSCALL_64_after_hwframe+0x42/0xb7
    SOFTIRQ-ON-W at:
                      down_write+0x3e/0xa0
                      __link_block_group+0x34/0x130 [btrfs]
                      btrfs_read_block_groups+0x33d/0x7b0 [btrfs]
                      open_ctree+0x2054/0x2660 [btrfs]
                      btrfs_mount+0xd36/0xf90 [btrfs]
                      mount_fs+0x3a/0x160
                      vfs_kern_mount+0x66/0x150
                      btrfs_mount+0x18c/0xf90 [btrfs]
                      mount_fs+0x3a/0x160
                      vfs_kern_mount+0x66/0x150
                      do_mount+0x1c1/0xcc0
                      SyS_mount+0x7e/0xd0
                      do_syscall_64+0x79/0x1e0
                      entry_SYSCALL_64_after_hwframe+0x42/0xb7
    SOFTIRQ-ON-R at:
                      down_read+0x35/0x90
                      btrfs_calc_num_tolerated_disk_barrier_failures+0x113/0x1f0 [btrfs]
                      open_ctree+0x207b/0x2660 [btrfs]
                      btrfs_mount+0xd36/0xf90 [btrfs]
                      mount_fs+0x3a/0x160
                      vfs_kern_mount+0x66/0x150
                      btrfs_mount+0x18c/0xf90 [btrfs]
                      mount_fs+0x3a/0x160
                      vfs_kern_mount+0x66/0x150
                      do_mount+0x1c1/0xcc0
                      SyS_mount+0x7e/0xd0
                      do_syscall_64+0x79/0x1e0
                      entry_SYSCALL_64_after_hwframe+0x42/0xb7
    INITIAL USE at:
                     down_write+0x3e/0xa0
                     __link_block_group+0x34/0x130 [btrfs]
                     btrfs_read_block_groups+0x33d/0x7b0 [btrfs]
                     open_ctree+0x2054/0x2660 [btrfs]
                     btrfs_mount+0xd36/0xf90 [btrfs]
                     mount_fs+0x3a/0x160
                     vfs_kern_mount+0x66/0x150
                     btrfs_mount+0x18c/0xf90 [btrfs]
                     mount_fs+0x3a/0x160
                     vfs_kern_mount+0x66/0x150
                     do_mount+0x1c1/0xcc0
                     SyS_mount+0x7e/0xd0
                     do_syscall_64+0x79/0x1e0
                     entry_SYSCALL_64_after_hwframe+0x42/0xb7
  }
  ... key      at: [<ffffffffc0729488>] __key.59101+0x0/0xfffffffffff9ab78 [btrfs]
  ... acquired at:
   find_free_extent+0xcb4/0x12d0 [btrfs]
   btrfs_reserve_extent+0xd8/0x170 [btrfs]
   btrfs_alloc_tree_block+0x12f/0x4c0 [btrfs]
   __btrfs_cow_block+0x110/0x5b0 [btrfs]
   btrfs_cow_block+0xd7/0x290 [btrfs]
   btrfs_search_slot+0x1f6/0x960 [btrfs]
   btrfs_lookup_inode+0x2a/0x90 [btrfs]
   __btrfs_update_delayed_inode+0x65/0x210 [btrfs]
   btrfs_commit_inode_delayed_inode+0x121/0x130 [btrfs]
   btrfs_evict_inode+0x3fe/0x6a0 [btrfs]
   evict+0xc4/0x190
   __dentry_kill+0xbf/0x170
   dput+0x2ae/0x2f0
   SyS_rename+0x2a6/0x3b0
   do_syscall_64+0x79/0x1e0
   entry_SYSCALL_64_after_hwframe+0x42/0xb7

-> (&delayed_node->mutex){+.+.-.} ops: 5580204 {
   HARDIRQ-ON-W at:
                    __mutex_lock+0x4e/0x8c0
                    btrfs_delayed_update_inode+0x46/0x6e0 [btrfs]
                    btrfs_update_inode+0x83/0x110 [btrfs]
                    btrfs_dirty_inode+0x62/0xe0 [btrfs]
                    touch_atime+0x8c/0xb0
                    do_generic_file_read+0x818/0xb10
                    __vfs_read+0xdc/0x150
                    vfs_read+0x8a/0x130
                    SyS_read+0x45/0xa0
                    do_syscall_64+0x79/0x1e0
                    entry_SYSCALL_64_after_hwframe+0x42/0xb7
   SOFTIRQ-ON-W at:
                    __mutex_lock+0x4e/0x8c0
                    btrfs_delayed_update_inode+0x46/0x6e0 [btrfs]
                    btrfs_update_inode+0x83/0x110 [btrfs]
                    btrfs_dirty_inode+0x62/0xe0 [btrfs]
                    touch_atime+0x8c/0xb0
                    do_generic_file_read+0x818/0xb10
                    __vfs_read+0xdc/0x150
                    vfs_read+0x8a/0x130
                    SyS_read+0x45/0xa0
                    do_syscall_64+0x79/0x1e0
                    entry_SYSCALL_64_after_hwframe+0x42/0xb7
   IN-RECLAIM_FS-W at:
                       __mutex_lock+0x4e/0x8c0
                       __btrfs_release_delayed_node+0x3a/0x1f0 [btrfs]
                       btrfs_evict_inode+0x22c/0x6a0 [btrfs]
                       evict+0xc4/0x190
                       dispose_list+0x35/0x50
                       prune_icache_sb+0x42/0x50
                       super_cache_scan+0x139/0x190
                       shrink_slab+0x262/0x5b0
                       shrink_node+0x2eb/0x2f0
                       kswapd+0x2eb/0x890
                       kthread+0x102/0x140
                       ret_from_fork+0x3a/0x50
   INITIAL USE at:
                   __mutex_lock+0x4e/0x8c0
                   btrfs_delayed_update_inode+0x46/0x6e0 [btrfs]
                   btrfs_update_inode+0x83/0x110 [btrfs]
                   btrfs_dirty_inode+0x62/0xe0 [btrfs]
                   touch_atime+0x8c/0xb0
                   do_generic_file_read+0x818/0xb10
                   __vfs_read+0xdc/0x150
                   vfs_read+0x8a/0x130
                   SyS_read+0x45/0xa0
                   do_syscall_64+0x79/0x1e0
                   entry_SYSCALL_64_after_hwframe+0x42/0xb7
 }
 ... key      at: [<ffffffffc072d488>] __key.56935+0x0/0xfffffffffff96b78 [btrfs]
 ... acquired at:
   __lock_acquire+0x264/0x11c0
   lock_acquire+0xbd/0x1e0
   __mutex_lock+0x4e/0x8c0
   __btrfs_release_delayed_node+0x3a/0x1f0 [btrfs]
   btrfs_evict_inode+0x22c/0x6a0 [btrfs]
   evict+0xc4/0x190
   dispose_list+0x35/0x50
   prune_icache_sb+0x42/0x50
   super_cache_scan+0x139/0x190
   shrink_slab+0x262/0x5b0
   shrink_node+0x2eb/0x2f0
   kswapd+0x2eb/0x890
   kthread+0x102/0x140
   ret_from_fork+0x3a/0x50

stack backtrace:
CPU: 1 PID: 50 Comm: kswapd0 Tainted: G        W        4.12.14-kvmsmall #8 SLE15 (unreleased)
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.0.0-prebuilt.qemu-project.org 04/01/2014
Call Trace:
 dump_stack+0x78/0xb7
 print_irq_inversion_bug.part.38+0x19f/0x1aa
 check_usage_forwards+0x102/0x120
 ? ret_from_fork+0x3a/0x50
 ? check_usage_backwards+0x110/0x110
 mark_lock+0x16c/0x270
 __lock_acquire+0x264/0x11c0
 ? pagevec_lookup_entries+0x1a/0x30
 ? truncate_inode_pages_range+0x2b3/0x7f0
 lock_acquire+0xbd/0x1e0
 ? __btrfs_release_delayed_node+0x3a/0x1f0 [btrfs]
 __mutex_lock+0x4e/0x8c0
 ? __btrfs_release_delayed_node+0x3a/0x1f0 [btrfs]
 ? __btrfs_release_delayed_node+0x3a/0x1f0 [btrfs]
 ? btrfs_evict_inode+0x1f6/0x6a0 [btrfs]
 __btrfs_release_delayed_node+0x3a/0x1f0 [btrfs]
 btrfs_evict_inode+0x22c/0x6a0 [btrfs]
 evict+0xc4/0x190
 dispose_list+0x35/0x50
 prune_icache_sb+0x42/0x50
 super_cache_scan+0x139/0x190
 shrink_slab+0x262/0x5b0
 shrink_node+0x2eb/0x2f0
 kswapd+0x2eb/0x890
 kthread+0x102/0x140
 ? mem_cgroup_shrink_node+0x2c0/0x2c0
 ? kthread_create_on_node+0x40/0x40
 ret_from_fork+0x3a/0x50
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Reviewed-by: Liu Bo <bo.liu@linux.alibaba.com>
Signed-off-by: David Sterba <dsterba@suse.com>

Drop optimal argument from the function find_live_mirror() as we can
deduce it in the function itself. Also rename optimal to
preferred_mirror.
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

Obtain the stripes info from the map directly and so no need
to pass it as an argument.
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

It's provided by transaction handle.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

It's provided by the transaction handle.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

It's provided by the transaction handle.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

It's provided by the transaction handle.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

Added by 08e007d2 ("Btrfs: improve the noflush reservation") and
made redundant by 17024ad0 ("Btrfs: fix early ENOSPC due to
delalloc").
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

Added by b4570aa9 ("btrfs: fix compiling with CONFIG_BTRFS_DEBUG
enabled.") and obsoleted by 2ff7e61e ("btrfs: take an fs_info
directly when the root is not used otherwise").
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

Introduced by 5cdc7ad3 ("btrfs: Replace fs_info->workers with
btrfs_workqueue.") but obsoleted by 2a458198 ("btrfs: factor
btrfs_init_workqueues() out of open_ctree()").
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

Added in 38c227d8 ("Btrfs: snapshot-aware defrag") but subsequently
made redundant by 0b246afa ("btrfs: root->fs_info cleanup, add
fs_info convenience variables").
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

Added already unused in a6fa6fae ("btrfs: Add lzo compression
support").
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

Added in b5d67f64 ("Btrfs: change scrub to support big blocks") but
rendered redundant by be50a8dd ("Btrfs: Simplify
scrub_setup_recheck_block()'s argument").
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

Added as part of 86d5f994 ("btrfs: convert prelimary reference
tracking to use rbtrees") but never used. tmp_op_key essentially
subsumed that variable.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

When checking the minimal nr_devs, there is one dead and meaningless
condition:

if (ndevs < devs_increment * sub_stripes || ndevs < devs_min) {
    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

This condition is meaningless, @devs_increment has nothing to do with
@sub_stripes.

In fact, in btrfs_raid_array[], profile with sub_stripes larger than 1
(RAID10) already has the @devs_increment set to 2.
So no need to multiple it by @sub_stripes.

And above condition is also dead.
For RAID10, @devs_increment * @sub_stripes equals 4, which is also the
@devs_min of RAID10.
For other profiles, @sub_stripes is always 1, and since @ndevs is
rounded down to @devs_increment, the condition will always be true.

Remove the meaningless condition to make later reader wander less.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

This function is the entry to the extent allocator and as such has
quite a number of parameters. Some of those have subtle effects on the
allocation algorithm. Document the parameters.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>

As with every function which deals with modifying the btree
btrfs_uuid_tree_rem can fail for any number of reasons (ie. EIO/ENOMEM).
Handle return error value from this function gracefully by aborting the
transaction.

Fixes: dd5f9615 ("Btrfs: maintain subvolume items in the UUID tree")
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

The kernel would like to have all stack VLA usage removed[1].
Unfortunately using an integer constant variable as the size of an
array is still considered a VLA. Instead let's use directly sizeof(var)
which removes the VLA usage. Use the occasion to remove csum_size
altogether and use sizeof() also for the size passed to memcmp

[1]: https://lkml.org/lkml/2018/3/7/621Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

Signed-off-by: David Sterba <dsterba@suse.com>

Remove parameters not used by any of the callbacks.
Signed-off-by: David Sterba <dsterba@suse.com>

Remove parameters not used by any of the callbacks.
Signed-off-by: David Sterba <dsterba@suse.com>

The callbacks make use of different parameters that are passed to the
other type unnecessarily. This patch adds separate types for each and
the unused parameters will be removed.

The type extent_submit_bio_hook_t keeps all parameters and can be used
where the start/done types are not appropriate.
Signed-off-by: David Sterba <dsterba@suse.com>

A useless wrapper around tree_mod_log_insert_root that hides missing
error handling. Move it to the callers.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

A trivial wrapper that can be simply opencoded and makes the GFP
allocation request more visible. The error handling is now moved to the
callers.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

The wrapper is effectively an alias for tree_mod_log_insert_move but
also hides the missing error handling. To make that more visible, lift
the BUG_ON to the callers.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

The wrappers are trivial and do not bring any extra value on top of the
plain locking primitives.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

It's provided by the extent_buffer.
Signed-off-by: David Sterba <dsterba@suse.com>

The tree_mod_move is not used anywhere and can be embedded as anonymous
structure.
Signed-off-by: David Sterba <dsterba@suse.com>