Commit Graph

11395 Commits

Author SHA1 Message Date
Linus Torvalds
75f4d9af8b iov_iter work; most of that is about getting rid of
direction misannotations and (hopefully) preventing
 more of the same for the future.
 
 Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Merge tag 'pull-iov_iter' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull iov_iter updates from Al Viro:
 "iov_iter work; most of that is about getting rid of direction
  misannotations and (hopefully) preventing more of the same for the
  future"

* tag 'pull-iov_iter' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  use less confusing names for iov_iter direction initializers
  iov_iter: saner checks for attempt to copy to/from iterator
  [xen] fix "direction" argument of iov_iter_kvec()
  [vhost] fix 'direction' argument of iov_iter_{init,bvec}()
  [target] fix iov_iter_bvec() "direction" argument
  [s390] memcpy_real(): WRITE is "data source", not destination...
  [s390] zcore: WRITE is "data source", not destination...
  [infiniband] READ is "data destination", not source...
  [fsi] WRITE is "data source", not destination...
  [s390] copy_oldmem_kernel() - WRITE is "data source", not destination
  csum_and_copy_to_iter(): handle ITER_DISCARD
  get rid of unlikely() on page_copy_sane() calls
2022-12-12 18:29:54 -08:00
Linus Torvalds
3eaea0db25 for-6.1-rc6-tag
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Merge tag 'for-6.1-rc6-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux

Pull btrfs fixes from David Sterba:

 - fix a regression in nowait + buffered write

 - in zoned mode fix endianness when comparing super block generation

 - locking and lockdep fixes:
     - fix potential sleeping under spinlock when setting qgroup limit
     - lockdep warning fixes when btrfs_path is freed after copy_to_user
     - do not modify log tree while holding a leaf from fs tree locked

 - fix freeing of sysfs files of static features on error

 - use kv.alloc for zone map allocation as a fallback to avoid warnings
   due to high order allocation

 - send, avoid unaligned encoded writes when attempting to clone range

* tag 'for-6.1-rc6-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
  btrfs: sysfs: normalize the error handling branch in btrfs_init_sysfs()
  btrfs: do not modify log tree while holding a leaf from fs tree locked
  btrfs: use kvcalloc in btrfs_get_dev_zone_info
  btrfs: qgroup: fix sleep from invalid context bug in btrfs_qgroup_inherit()
  btrfs: send: avoid unaligned encoded writes when attempting to clone range
  btrfs: zoned: fix missing endianness conversion in sb_write_pointer
  btrfs: free btrfs_path before copying subvol info to userspace
  btrfs: free btrfs_path before copying fspath to userspace
  btrfs: free btrfs_path before copying inodes to userspace
  btrfs: free btrfs_path before copying root refs to userspace
  btrfs: fix assertion failure and blocking during nowait buffered write
2022-11-25 13:24:05 -08:00
Al Viro
de4eda9de2 use less confusing names for iov_iter direction initializers
READ/WRITE proved to be actively confusing - the meanings are
"data destination, as used with read(2)" and "data source, as
used with write(2)", but people keep interpreting those as
"we read data from it" and "we write data to it", i.e. exactly
the wrong way.

Call them ITER_DEST and ITER_SOURCE - at least that is harder
to misinterpret...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2022-11-25 13:01:55 -05:00
Zhen Lei
ffdbb44f2f btrfs: sysfs: normalize the error handling branch in btrfs_init_sysfs()
Although kset_unregister() can eventually remove all attribute files,
explicitly rolling back with the matching function makes the code logic
look clearer.

CC: stable@vger.kernel.org # 5.4+
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-11-23 16:52:22 +01:00
Filipe Manana
796787c978 btrfs: do not modify log tree while holding a leaf from fs tree locked
When logging an inode in full mode, or when logging xattrs or when logging
the dir index items of a directory, we are modifying the log tree while
holding a read lock on a leaf from the fs/subvolume tree. This can lead to
a deadlock in rare circumstances, but it is a real possibility, and it was
recently reported by syzbot with the following trace from lockdep:

   WARNING: possible circular locking dependency detected
   6.1.0-rc5-next-20221116-syzkaller #0 Not tainted
   ------------------------------------------------------
   syz-executor.1/16154 is trying to acquire lock:
   ffff88807e3084a0 (&delayed_node->mutex){+.+.}-{3:3}, at: __btrfs_release_delayed_node.part.0+0xa1/0xf30 fs/btrfs/delayed-inode.c:256

   but task is already holding lock:
   ffff88807df33078 (btrfs-log-00){++++}-{3:3}, at: __btrfs_tree_lock+0x32/0x3d0 fs/btrfs/locking.c:197

   which lock already depends on the new lock.

   the existing dependency chain (in reverse order) is:

   -> #2 (btrfs-log-00){++++}-{3:3}:
          down_read_nested+0x9e/0x450 kernel/locking/rwsem.c:1634
          __btrfs_tree_read_lock+0x32/0x350 fs/btrfs/locking.c:135
          btrfs_tree_read_lock fs/btrfs/locking.c:141 [inline]
          btrfs_read_lock_root_node+0x82/0x3a0 fs/btrfs/locking.c:280
          btrfs_search_slot_get_root fs/btrfs/ctree.c:1678 [inline]
          btrfs_search_slot+0x3ca/0x2c70 fs/btrfs/ctree.c:1998
          btrfs_lookup_csum+0x116/0x3f0 fs/btrfs/file-item.c:209
          btrfs_csum_file_blocks+0x40e/0x1370 fs/btrfs/file-item.c:1021
          log_csums.isra.0+0x244/0x2d0 fs/btrfs/tree-log.c:4258
          copy_items.isra.0+0xbfb/0xed0 fs/btrfs/tree-log.c:4403
          copy_inode_items_to_log+0x13d6/0x1d90 fs/btrfs/tree-log.c:5873
          btrfs_log_inode+0xb19/0x4680 fs/btrfs/tree-log.c:6495
          btrfs_log_inode_parent+0x890/0x2a20 fs/btrfs/tree-log.c:6982
          btrfs_log_dentry_safe+0x59/0x80 fs/btrfs/tree-log.c:7083
          btrfs_sync_file+0xa41/0x13c0 fs/btrfs/file.c:1921
          vfs_fsync_range+0x13e/0x230 fs/sync.c:188
          generic_write_sync include/linux/fs.h:2856 [inline]
          iomap_dio_complete+0x73a/0x920 fs/iomap/direct-io.c:128
          btrfs_direct_write fs/btrfs/file.c:1536 [inline]
          btrfs_do_write_iter+0xba2/0x1470 fs/btrfs/file.c:1668
          call_write_iter include/linux/fs.h:2160 [inline]
          do_iter_readv_writev+0x20b/0x3b0 fs/read_write.c:735
          do_iter_write+0x182/0x700 fs/read_write.c:861
          vfs_iter_write+0x74/0xa0 fs/read_write.c:902
          iter_file_splice_write+0x745/0xc90 fs/splice.c:686
          do_splice_from fs/splice.c:764 [inline]
          direct_splice_actor+0x114/0x180 fs/splice.c:931
          splice_direct_to_actor+0x335/0x8a0 fs/splice.c:886
          do_splice_direct+0x1ab/0x280 fs/splice.c:974
          do_sendfile+0xb19/0x1270 fs/read_write.c:1255
          __do_sys_sendfile64 fs/read_write.c:1323 [inline]
          __se_sys_sendfile64 fs/read_write.c:1309 [inline]
          __x64_sys_sendfile64+0x259/0x2c0 fs/read_write.c:1309
          do_syscall_x64 arch/x86/entry/common.c:50 [inline]
          do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
          entry_SYSCALL_64_after_hwframe+0x63/0xcd

   -> #1 (btrfs-tree-00){++++}-{3:3}:
          __lock_release kernel/locking/lockdep.c:5382 [inline]
          lock_release+0x371/0x810 kernel/locking/lockdep.c:5688
          up_write+0x2a/0x520 kernel/locking/rwsem.c:1614
          btrfs_tree_unlock_rw fs/btrfs/locking.h:189 [inline]
          btrfs_unlock_up_safe+0x1e3/0x290 fs/btrfs/locking.c:238
          search_leaf fs/btrfs/ctree.c:1832 [inline]
          btrfs_search_slot+0x265e/0x2c70 fs/btrfs/ctree.c:2074
          btrfs_insert_empty_items+0xbd/0x1c0 fs/btrfs/ctree.c:4133
          btrfs_insert_delayed_item+0x826/0xfa0 fs/btrfs/delayed-inode.c:746
          btrfs_insert_delayed_items fs/btrfs/delayed-inode.c:824 [inline]
          __btrfs_commit_inode_delayed_items fs/btrfs/delayed-inode.c:1111 [inline]
          __btrfs_run_delayed_items+0x280/0x590 fs/btrfs/delayed-inode.c:1153
          flush_space+0x147/0xe90 fs/btrfs/space-info.c:728
          btrfs_async_reclaim_metadata_space+0x541/0xc10 fs/btrfs/space-info.c:1086
          process_one_work+0x9bf/0x1710 kernel/workqueue.c:2289
          worker_thread+0x669/0x1090 kernel/workqueue.c:2436
          kthread+0x2e8/0x3a0 kernel/kthread.c:376
          ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308

   -> #0 (&delayed_node->mutex){+.+.}-{3:3}:
          check_prev_add kernel/locking/lockdep.c:3097 [inline]
          check_prevs_add kernel/locking/lockdep.c:3216 [inline]
          validate_chain kernel/locking/lockdep.c:3831 [inline]
          __lock_acquire+0x2a43/0x56d0 kernel/locking/lockdep.c:5055
          lock_acquire kernel/locking/lockdep.c:5668 [inline]
          lock_acquire+0x1e3/0x630 kernel/locking/lockdep.c:5633
          __mutex_lock_common kernel/locking/mutex.c:603 [inline]
          __mutex_lock+0x12f/0x1360 kernel/locking/mutex.c:747
          __btrfs_release_delayed_node.part.0+0xa1/0xf30 fs/btrfs/delayed-inode.c:256
          __btrfs_release_delayed_node fs/btrfs/delayed-inode.c:251 [inline]
          btrfs_release_delayed_node fs/btrfs/delayed-inode.c:281 [inline]
          btrfs_remove_delayed_node+0x52/0x60 fs/btrfs/delayed-inode.c:1285
          btrfs_evict_inode+0x511/0xf30 fs/btrfs/inode.c:5554
          evict+0x2ed/0x6b0 fs/inode.c:664
          dispose_list+0x117/0x1e0 fs/inode.c:697
          prune_icache_sb+0xeb/0x150 fs/inode.c:896
          super_cache_scan+0x391/0x590 fs/super.c:106
          do_shrink_slab+0x464/0xce0 mm/vmscan.c:843
          shrink_slab_memcg mm/vmscan.c:912 [inline]
          shrink_slab+0x388/0x660 mm/vmscan.c:991
          shrink_node_memcgs mm/vmscan.c:6088 [inline]
          shrink_node+0x93d/0x1f30 mm/vmscan.c:6117
          shrink_zones mm/vmscan.c:6355 [inline]
          do_try_to_free_pages+0x3b4/0x17a0 mm/vmscan.c:6417
          try_to_free_mem_cgroup_pages+0x3a4/0xa70 mm/vmscan.c:6732
          reclaim_high.constprop.0+0x182/0x230 mm/memcontrol.c:2393
          mem_cgroup_handle_over_high+0x190/0x520 mm/memcontrol.c:2578
          try_charge_memcg+0xe0c/0x12f0 mm/memcontrol.c:2816
          try_charge mm/memcontrol.c:2827 [inline]
          charge_memcg+0x90/0x3b0 mm/memcontrol.c:6889
          __mem_cgroup_charge+0x2b/0x90 mm/memcontrol.c:6910
          mem_cgroup_charge include/linux/memcontrol.h:667 [inline]
          __filemap_add_folio+0x615/0xf80 mm/filemap.c:852
          filemap_add_folio+0xaf/0x1e0 mm/filemap.c:934
          __filemap_get_folio+0x389/0xd80 mm/filemap.c:1976
          pagecache_get_page+0x2e/0x280 mm/folio-compat.c:104
          find_or_create_page include/linux/pagemap.h:612 [inline]
          alloc_extent_buffer+0x2b9/0x1580 fs/btrfs/extent_io.c:4588
          btrfs_init_new_buffer fs/btrfs/extent-tree.c:4869 [inline]
          btrfs_alloc_tree_block+0x2e1/0x1320 fs/btrfs/extent-tree.c:4988
          __btrfs_cow_block+0x3b2/0x1420 fs/btrfs/ctree.c:440
          btrfs_cow_block+0x2fa/0x950 fs/btrfs/ctree.c:595
          btrfs_search_slot+0x11b0/0x2c70 fs/btrfs/ctree.c:2038
          btrfs_update_root+0xdb/0x630 fs/btrfs/root-tree.c:137
          update_log_root fs/btrfs/tree-log.c:2841 [inline]
          btrfs_sync_log+0xbfb/0x2870 fs/btrfs/tree-log.c:3064
          btrfs_sync_file+0xdb9/0x13c0 fs/btrfs/file.c:1947
          vfs_fsync_range+0x13e/0x230 fs/sync.c:188
          generic_write_sync include/linux/fs.h:2856 [inline]
          iomap_dio_complete+0x73a/0x920 fs/iomap/direct-io.c:128
          btrfs_direct_write fs/btrfs/file.c:1536 [inline]
          btrfs_do_write_iter+0xba2/0x1470 fs/btrfs/file.c:1668
          call_write_iter include/linux/fs.h:2160 [inline]
          do_iter_readv_writev+0x20b/0x3b0 fs/read_write.c:735
          do_iter_write+0x182/0x700 fs/read_write.c:861
          vfs_iter_write+0x74/0xa0 fs/read_write.c:902
          iter_file_splice_write+0x745/0xc90 fs/splice.c:686
          do_splice_from fs/splice.c:764 [inline]
          direct_splice_actor+0x114/0x180 fs/splice.c:931
          splice_direct_to_actor+0x335/0x8a0 fs/splice.c:886
          do_splice_direct+0x1ab/0x280 fs/splice.c:974
          do_sendfile+0xb19/0x1270 fs/read_write.c:1255
          __do_sys_sendfile64 fs/read_write.c:1323 [inline]
          __se_sys_sendfile64 fs/read_write.c:1309 [inline]
          __x64_sys_sendfile64+0x259/0x2c0 fs/read_write.c:1309
          do_syscall_x64 arch/x86/entry/common.c:50 [inline]
          do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
          entry_SYSCALL_64_after_hwframe+0x63/0xcd

   other info that might help us debug this:

   Chain exists of:
     &delayed_node->mutex --> btrfs-tree-00 --> btrfs-log-00

   Possible unsafe locking scenario:

          CPU0                    CPU1
          ----                    ----
     lock(btrfs-log-00);
                                  lock(btrfs-tree-00);
                                  lock(btrfs-log-00);
     lock(&delayed_node->mutex);

Holding a read lock on a leaf from a fs/subvolume tree creates a nasty
lock dependency when we are COWing extent buffers for the log tree and we
have two tasks modifying the log tree, with each one in one of the
following 2 scenarios:

1) Modifying the log tree triggers an extent buffer allocation while
   holding a write lock on a parent extent buffer from the log tree.
   Allocating the pages for an extent buffer, or the extent buffer
   struct, can trigger inode eviction and finally the inode eviction
   will trigger a release/remove of a delayed node, which requires
   taking the delayed node's mutex;

2) Allocating a metadata extent for a log tree can trigger the async
   reclaim thread and make us wait for it to release enough space and
   unblock our reservation ticket. The reclaim thread can start flushing
   delayed items, and that in turn results in the need to lock delayed
   node mutexes and in the need to write lock extent buffers of a
   subvolume tree - all this while holding a write lock on the parent
   extent buffer in the log tree.

So one task in scenario 1) running in parallel with another task in
scenario 2) could lead to a deadlock, one wanting to lock a delayed node
mutex while having a read lock on a leaf from the subvolume, while the
other is holding the delayed node's mutex and wants to write lock the same
subvolume leaf for flushing delayed items.

Fix this by cloning the leaf of the fs/subvolume tree, release/unlock the
fs/subvolume leaf and use the clone leaf instead.

Reported-by: syzbot+9b7c21f486f5e7f8d029@syzkaller.appspotmail.com
Link: https://lore.kernel.org/linux-btrfs/000000000000ccc93c05edc4d8cf@google.com/
CC: stable@vger.kernel.org # 6.0+
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-11-23 16:52:15 +01:00
Christoph Hellwig
8fe97d47b5 btrfs: use kvcalloc in btrfs_get_dev_zone_info
Otherwise the kernel memory allocator seems to be unhappy about failing
order 6 allocations for the zones array, that cause 100% reproducible
mount failures in my qemu setup:

  [26.078981] mount: page allocation failure: order:6, mode:0x40dc0(GFP_KERNEL|__GFP_COMP|__GFP_ZERO), nodemask=(null)
  [26.079741] CPU: 0 PID: 2965 Comm: mount Not tainted 6.1.0-rc5+ #185
  [26.080181] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014
  [26.080950] Call Trace:
  [26.081132]  <TASK>
  [26.081291]  dump_stack_lvl+0x56/0x6f
  [26.081554]  warn_alloc+0x117/0x140
  [26.081808]  ? __alloc_pages_direct_compact+0x1b5/0x300
  [26.082174]  __alloc_pages_slowpath.constprop.0+0xd0e/0xde0
  [26.082569]  __alloc_pages+0x32a/0x340
  [26.082836]  __kmalloc_large_node+0x4d/0xa0
  [26.083133]  ? trace_kmalloc+0x29/0xd0
  [26.083399]  kmalloc_large+0x14/0x60
  [26.083654]  btrfs_get_dev_zone_info+0x1b9/0xc00
  [26.083980]  ? _raw_spin_unlock_irqrestore+0x28/0x50
  [26.084328]  btrfs_get_dev_zone_info_all_devices+0x54/0x80
  [26.084708]  open_ctree+0xed4/0x1654
  [26.084974]  btrfs_mount_root.cold+0x12/0xde
  [26.085288]  ? lock_is_held_type+0xe2/0x140
  [26.085603]  legacy_get_tree+0x28/0x50
  [26.085876]  vfs_get_tree+0x1d/0xb0
  [26.086139]  vfs_kern_mount.part.0+0x6c/0xb0
  [26.086456]  btrfs_mount+0x118/0x3a0
  [26.086728]  ? lock_is_held_type+0xe2/0x140
  [26.087043]  legacy_get_tree+0x28/0x50
  [26.087323]  vfs_get_tree+0x1d/0xb0
  [26.087587]  path_mount+0x2ba/0xbe0
  [26.087850]  ? _raw_spin_unlock_irqrestore+0x38/0x50
  [26.088217]  __x64_sys_mount+0xfe/0x140
  [26.088506]  do_syscall_64+0x35/0x80
  [26.088776]  entry_SYSCALL_64_after_hwframe+0x63/0xcd

Fixes: 5b31646898 ("btrfs: get zone information of zoned block devices")
CC: stable@vger.kernel.org # 5.15+
Reviewed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-11-23 16:51:50 +01:00
ChenXiaoSong
f7e942b5bb btrfs: qgroup: fix sleep from invalid context bug in btrfs_qgroup_inherit()
Syzkaller reported BUG as follows:

  BUG: sleeping function called from invalid context at
       include/linux/sched/mm.h:274
  Call Trace:
   <TASK>
   dump_stack_lvl+0xcd/0x134
   __might_resched.cold+0x222/0x26b
   kmem_cache_alloc+0x2e7/0x3c0
   update_qgroup_limit_item+0xe1/0x390
   btrfs_qgroup_inherit+0x147b/0x1ee0
   create_subvol+0x4eb/0x1710
   btrfs_mksubvol+0xfe5/0x13f0
   __btrfs_ioctl_snap_create+0x2b0/0x430
   btrfs_ioctl_snap_create_v2+0x25a/0x520
   btrfs_ioctl+0x2a1c/0x5ce0
   __x64_sys_ioctl+0x193/0x200
   do_syscall_64+0x35/0x80

Fix this by calling qgroup_dirty() on @dstqgroup, and update limit item in
btrfs_run_qgroups() later outside of the spinlock context.

CC: stable@vger.kernel.org # 4.9+
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: ChenXiaoSong <chenxiaosong2@huawei.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-11-21 14:57:52 +01:00
Filipe Manana
a11452a370 btrfs: send: avoid unaligned encoded writes when attempting to clone range
When trying to see if we can clone a file range, there are cases where we
end up sending two write operations in case the inode from the source root
has an i_size that is not sector size aligned and the length from the
current offset to its i_size is less than the remaining length we are
trying to clone.

Issuing two write operations when we could instead issue a single write
operation is not incorrect. However it is not optimal, specially if the
extents are compressed and the flag BTRFS_SEND_FLAG_COMPRESSED was passed
to the send ioctl. In that case we can end up sending an encoded write
with an offset that is not sector size aligned, which makes the receiver
fallback to decompressing the data and writing it using regular buffered
IO (so re-compressing the data in case the fs is mounted with compression
enabled), because encoded writes fail with -EINVAL when an offset is not
sector size aligned.

The following example, which triggered a bug in the receiver code for the
fallback logic of decompressing + regular buffer IO and is fixed by the
patchset referred in a Link at the bottom of this changelog, is an example
where we have the non-optimal behaviour due to an unaligned encoded write:

   $ cat test.sh
   #!/bin/bash

   DEV=/dev/sdj
   MNT=/mnt/sdj

   mkfs.btrfs -f $DEV > /dev/null
   mount -o compress $DEV $MNT

   # File foo has a size of 33K, not aligned to the sector size.
   xfs_io -f -c "pwrite -S 0xab 0 33K" $MNT/foo

   xfs_io -f -c "pwrite -S 0xcd 0 64K" $MNT/bar

   # Now clone the first 32K of file bar into foo at offset 0.
   xfs_io -c "reflink $MNT/bar 0 0 32K" $MNT/foo

   # Snapshot the default subvolume and create a full send stream (v2).
   btrfs subvolume snapshot -r $MNT $MNT/snap

   btrfs send --compressed-data -f /tmp/test.send $MNT/snap

   echo -e "\nFile bar in the original filesystem:"
   od -A d -t x1 $MNT/snap/bar

   umount $MNT
   mkfs.btrfs -f $DEV > /dev/null
   mount $DEV $MNT

   echo -e "\nReceiving stream in a new filesystem..."
   btrfs receive -f /tmp/test.send $MNT

   echo -e "\nFile bar in the new filesystem:"
   od -A d -t x1 $MNT/snap/bar

   umount $MNT

Before this patch, the send stream included one regular write and one
encoded write for file 'bar', with the later being not sector size aligned
and causing the receiver to fallback to decompression + buffered writes.
The output of the btrfs receive command in verbose mode (-vvv):

   (...)
   mkfile o258-7-0
   rename o258-7-0 -> bar
   utimes
   clone bar - source=foo source offset=0 offset=0 length=32768
   write bar - offset=32768 length=1024
   encoded_write bar - offset=33792, len=4096, unencoded_offset=33792, unencoded_file_len=31744, unencoded_len=65536, compression=1, encryption=0
   encoded_write bar - falling back to decompress and write due to errno 22 ("Invalid argument")
   (...)

This patch avoids the regular write followed by an unaligned encoded write
so that we end up sending a single encoded write that is aligned. So after
this patch the stream content is (output of btrfs receive -vvv):

   (...)
   mkfile o258-7-0
   rename o258-7-0 -> bar
   utimes
   clone bar - source=foo source offset=0 offset=0 length=32768
   encoded_write bar - offset=32768, len=4096, unencoded_offset=32768, unencoded_file_len=32768, unencoded_len=65536, compression=1, encryption=0
   (...)

So we get more optimal behaviour and avoid the silent data loss bug in
versions of btrfs-progs affected by the bug referred by the Link tag
below (btrfs-progs v5.19, v5.19.1, v6.0 and v6.0.1).

Link: https://lore.kernel.org/linux-btrfs/cover.1668529099.git.fdmanana@suse.com/
Reviewed-by: Boris Burkov <boris@bur.io>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-11-21 14:41:41 +01:00
Christoph Hellwig
c51f0e6a12 btrfs: zoned: fix missing endianness conversion in sb_write_pointer
generation is an on-disk __le64 value, so use btrfs_super_generation to
convert it to host endian before comparing it.

Fixes: 12659251ca ("btrfs: implement log-structured superblock for ZONED mode")
CC: stable@vger.kernel.org # 5.15+
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-11-21 14:40:40 +01:00
Anand Jain
013c1c5585 btrfs: free btrfs_path before copying subvol info to userspace
btrfs_ioctl_get_subvol_info() frees the search path after the userspace
copy from the temp buffer @subvol_info. This can lead to a lock splat
warning.

Fix this by freeing the path before we copy it to userspace.

CC: stable@vger.kernel.org # 4.19+
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-11-15 17:15:45 +01:00
Anand Jain
8cf96b409d btrfs: free btrfs_path before copying fspath to userspace
btrfs_ioctl_ino_to_path() frees the search path after the userspace copy
from the temp buffer @ipath->fspath. Which potentially can lead to a lock
splat warning.

Fix this by freeing the path before we copy it to userspace.

CC: stable@vger.kernel.org # 4.19+
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-11-15 17:15:44 +01:00
Anand Jain
418ffb9e3c btrfs: free btrfs_path before copying inodes to userspace
btrfs_ioctl_logical_to_ino() frees the search path after the userspace
copy from the temp buffer @inodes. Which potentially can lead to a lock
splat.

Fix this by freeing the path before we copy @inodes to userspace.

CC: stable@vger.kernel.org # 4.19+
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-11-15 17:15:44 +01:00
Josef Bacik
b740d80616 btrfs: free btrfs_path before copying root refs to userspace
Syzbot reported the following lockdep splat

======================================================
WARNING: possible circular locking dependency detected
6.0.0-rc7-syzkaller-18095-gbbed346d5a96 #0 Not tainted
------------------------------------------------------
syz-executor307/3029 is trying to acquire lock:
ffff0000c02525d8 (&mm->mmap_lock){++++}-{3:3}, at: __might_fault+0x54/0xb4 mm/memory.c:5576

but task is already holding lock:
ffff0000c958a608 (btrfs-root-00){++++}-{3:3}, at: __btrfs_tree_read_lock fs/btrfs/locking.c:134 [inline]
ffff0000c958a608 (btrfs-root-00){++++}-{3:3}, at: btrfs_tree_read_lock fs/btrfs/locking.c:140 [inline]
ffff0000c958a608 (btrfs-root-00){++++}-{3:3}, at: btrfs_read_lock_root_node+0x13c/0x1c0 fs/btrfs/locking.c:279

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> #3 (btrfs-root-00){++++}-{3:3}:
       down_read_nested+0x64/0x84 kernel/locking/rwsem.c:1624
       __btrfs_tree_read_lock fs/btrfs/locking.c:134 [inline]
       btrfs_tree_read_lock fs/btrfs/locking.c:140 [inline]
       btrfs_read_lock_root_node+0x13c/0x1c0 fs/btrfs/locking.c:279
       btrfs_search_slot_get_root+0x74/0x338 fs/btrfs/ctree.c:1637
       btrfs_search_slot+0x1b0/0xfd8 fs/btrfs/ctree.c:1944
       btrfs_update_root+0x6c/0x5a0 fs/btrfs/root-tree.c:132
       commit_fs_roots+0x1f0/0x33c fs/btrfs/transaction.c:1459
       btrfs_commit_transaction+0x89c/0x12d8 fs/btrfs/transaction.c:2343
       flush_space+0x66c/0x738 fs/btrfs/space-info.c:786
       btrfs_async_reclaim_metadata_space+0x43c/0x4e0 fs/btrfs/space-info.c:1059
       process_one_work+0x2d8/0x504 kernel/workqueue.c:2289
       worker_thread+0x340/0x610 kernel/workqueue.c:2436
       kthread+0x12c/0x158 kernel/kthread.c:376
       ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:860

-> #2 (&fs_info->reloc_mutex){+.+.}-{3:3}:
       __mutex_lock_common+0xd4/0xca8 kernel/locking/mutex.c:603
       __mutex_lock kernel/locking/mutex.c:747 [inline]
       mutex_lock_nested+0x38/0x44 kernel/locking/mutex.c:799
       btrfs_record_root_in_trans fs/btrfs/transaction.c:516 [inline]
       start_transaction+0x248/0x944 fs/btrfs/transaction.c:752
       btrfs_start_transaction+0x34/0x44 fs/btrfs/transaction.c:781
       btrfs_create_common+0xf0/0x1b4 fs/btrfs/inode.c:6651
       btrfs_create+0x8c/0xb0 fs/btrfs/inode.c:6697
       lookup_open fs/namei.c:3413 [inline]
       open_last_lookups fs/namei.c:3481 [inline]
       path_openat+0x804/0x11c4 fs/namei.c:3688
       do_filp_open+0xdc/0x1b8 fs/namei.c:3718
       do_sys_openat2+0xb8/0x22c fs/open.c:1313
       do_sys_open fs/open.c:1329 [inline]
       __do_sys_openat fs/open.c:1345 [inline]
       __se_sys_openat fs/open.c:1340 [inline]
       __arm64_sys_openat+0xb0/0xe0 fs/open.c:1340
       __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
       invoke_syscall arch/arm64/kernel/syscall.c:52 [inline]
       el0_svc_common+0x138/0x220 arch/arm64/kernel/syscall.c:142
       do_el0_svc+0x48/0x164 arch/arm64/kernel/syscall.c:206
       el0_svc+0x58/0x150 arch/arm64/kernel/entry-common.c:636
       el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:654
       el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:581

-> #1 (sb_internal#2){.+.+}-{0:0}:
       percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
       __sb_start_write include/linux/fs.h:1826 [inline]
       sb_start_intwrite include/linux/fs.h:1948 [inline]
       start_transaction+0x360/0x944 fs/btrfs/transaction.c:683
       btrfs_join_transaction+0x30/0x40 fs/btrfs/transaction.c:795
       btrfs_dirty_inode+0x50/0x140 fs/btrfs/inode.c:6103
       btrfs_update_time+0x1c0/0x1e8 fs/btrfs/inode.c:6145
       inode_update_time fs/inode.c:1872 [inline]
       touch_atime+0x1f0/0x4a8 fs/inode.c:1945
       file_accessed include/linux/fs.h:2516 [inline]
       btrfs_file_mmap+0x50/0x88 fs/btrfs/file.c:2407
       call_mmap include/linux/fs.h:2192 [inline]
       mmap_region+0x7fc/0xc14 mm/mmap.c:1752
       do_mmap+0x644/0x97c mm/mmap.c:1540
       vm_mmap_pgoff+0xe8/0x1d0 mm/util.c:552
       ksys_mmap_pgoff+0x1cc/0x278 mm/mmap.c:1586
       __do_sys_mmap arch/arm64/kernel/sys.c:28 [inline]
       __se_sys_mmap arch/arm64/kernel/sys.c:21 [inline]
       __arm64_sys_mmap+0x58/0x6c arch/arm64/kernel/sys.c:21
       __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
       invoke_syscall arch/arm64/kernel/syscall.c:52 [inline]
       el0_svc_common+0x138/0x220 arch/arm64/kernel/syscall.c:142
       do_el0_svc+0x48/0x164 arch/arm64/kernel/syscall.c:206
       el0_svc+0x58/0x150 arch/arm64/kernel/entry-common.c:636
       el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:654
       el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:581

-> #0 (&mm->mmap_lock){++++}-{3:3}:
       check_prev_add kernel/locking/lockdep.c:3095 [inline]
       check_prevs_add kernel/locking/lockdep.c:3214 [inline]
       validate_chain kernel/locking/lockdep.c:3829 [inline]
       __lock_acquire+0x1530/0x30a4 kernel/locking/lockdep.c:5053
       lock_acquire+0x100/0x1f8 kernel/locking/lockdep.c:5666
       __might_fault+0x7c/0xb4 mm/memory.c:5577
       _copy_to_user include/linux/uaccess.h:134 [inline]
       copy_to_user include/linux/uaccess.h:160 [inline]
       btrfs_ioctl_get_subvol_rootref+0x3a8/0x4bc fs/btrfs/ioctl.c:3203
       btrfs_ioctl+0xa08/0xa64 fs/btrfs/ioctl.c:5556
       vfs_ioctl fs/ioctl.c:51 [inline]
       __do_sys_ioctl fs/ioctl.c:870 [inline]
       __se_sys_ioctl fs/ioctl.c:856 [inline]
       __arm64_sys_ioctl+0xd0/0x140 fs/ioctl.c:856
       __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
       invoke_syscall arch/arm64/kernel/syscall.c:52 [inline]
       el0_svc_common+0x138/0x220 arch/arm64/kernel/syscall.c:142
       do_el0_svc+0x48/0x164 arch/arm64/kernel/syscall.c:206
       el0_svc+0x58/0x150 arch/arm64/kernel/entry-common.c:636
       el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:654
       el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:581

other info that might help us debug this:

Chain exists of:
  &mm->mmap_lock --> &fs_info->reloc_mutex --> btrfs-root-00

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(btrfs-root-00);
                               lock(&fs_info->reloc_mutex);
                               lock(btrfs-root-00);
  lock(&mm->mmap_lock);

 *** DEADLOCK ***

1 lock held by syz-executor307/3029:
 #0: ffff0000c958a608 (btrfs-root-00){++++}-{3:3}, at: __btrfs_tree_read_lock fs/btrfs/locking.c:134 [inline]
 #0: ffff0000c958a608 (btrfs-root-00){++++}-{3:3}, at: btrfs_tree_read_lock fs/btrfs/locking.c:140 [inline]
 #0: ffff0000c958a608 (btrfs-root-00){++++}-{3:3}, at: btrfs_read_lock_root_node+0x13c/0x1c0 fs/btrfs/locking.c:279

stack backtrace:
CPU: 0 PID: 3029 Comm: syz-executor307 Not tainted 6.0.0-rc7-syzkaller-18095-gbbed346d5a96 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/30/2022
Call trace:
 dump_backtrace+0x1c4/0x1f0 arch/arm64/kernel/stacktrace.c:156
 show_stack+0x2c/0x54 arch/arm64/kernel/stacktrace.c:163
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x104/0x16c lib/dump_stack.c:106
 dump_stack+0x1c/0x58 lib/dump_stack.c:113
 print_circular_bug+0x2c4/0x2c8 kernel/locking/lockdep.c:2053
 check_noncircular+0x14c/0x154 kernel/locking/lockdep.c:2175
 check_prev_add kernel/locking/lockdep.c:3095 [inline]
 check_prevs_add kernel/locking/lockdep.c:3214 [inline]
 validate_chain kernel/locking/lockdep.c:3829 [inline]
 __lock_acquire+0x1530/0x30a4 kernel/locking/lockdep.c:5053
 lock_acquire+0x100/0x1f8 kernel/locking/lockdep.c:5666
 __might_fault+0x7c/0xb4 mm/memory.c:5577
 _copy_to_user include/linux/uaccess.h:134 [inline]
 copy_to_user include/linux/uaccess.h:160 [inline]
 btrfs_ioctl_get_subvol_rootref+0x3a8/0x4bc fs/btrfs/ioctl.c:3203
 btrfs_ioctl+0xa08/0xa64 fs/btrfs/ioctl.c:5556
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:870 [inline]
 __se_sys_ioctl fs/ioctl.c:856 [inline]
 __arm64_sys_ioctl+0xd0/0x140 fs/ioctl.c:856
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall arch/arm64/kernel/syscall.c:52 [inline]
 el0_svc_common+0x138/0x220 arch/arm64/kernel/syscall.c:142
 do_el0_svc+0x48/0x164 arch/arm64/kernel/syscall.c:206
 el0_svc+0x58/0x150 arch/arm64/kernel/entry-common.c:636
 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:654
 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:581

We do generally the right thing here, copying the references into a
temporary buffer, however we are still holding the path when we do
copy_to_user from the temporary buffer.  Fix this by freeing the path
before we copy to user space.

Reported-by: syzbot+4ef9e52e464c6ff47d9d@syzkaller.appspotmail.com
CC: stable@vger.kernel.org # 4.19+
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-11-15 15:01:05 +01:00
Filipe Manana
bdcdd86ca9 btrfs: fix assertion failure and blocking during nowait buffered write
When doing a nowait buffered write we can trigger the following assertion:

[11138.437027] assertion failed: !path->nowait, in fs/btrfs/ctree.c:4658
[11138.438251] ------------[ cut here ]------------
[11138.438254] kernel BUG at fs/btrfs/messages.c:259!
[11138.438762] invalid opcode: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC PTI
[11138.439450] CPU: 4 PID: 1091021 Comm: fsstress Not tainted 6.1.0-rc4-btrfs-next-128 #1
[11138.440611] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014
[11138.442553] RIP: 0010:btrfs_assertfail+0x19/0x1b [btrfs]
[11138.443583] Code: 5b 41 5a 41 (...)
[11138.446437] RSP: 0018:ffffbaf0cf05b840 EFLAGS: 00010246
[11138.447235] RAX: 0000000000000039 RBX: ffffbaf0cf05b938 RCX: 0000000000000000
[11138.448303] RDX: 0000000000000000 RSI: ffffffffb2ef59f6 RDI: 00000000ffffffff
[11138.449370] RBP: ffff9165f581eb68 R08: 00000000ffffffff R09: 0000000000000001
[11138.450493] R10: ffff9167a88421f8 R11: 0000000000000000 R12: ffff9164981b1000
[11138.451661] R13: 000000008c8f1000 R14: ffff9164991d4000 R15: ffff9164981b1000
[11138.452225] FS:  00007f1438a66440(0000) GS:ffff9167ad600000(0000) knlGS:0000000000000000
[11138.452949] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[11138.453394] CR2: 00007f1438a64000 CR3: 0000000100c36002 CR4: 0000000000370ee0
[11138.454057] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[11138.454879] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[11138.455779] Call Trace:
[11138.456211]  <TASK>
[11138.456598]  btrfs_next_old_leaf.cold+0x18/0x1d [btrfs]
[11138.457827]  ? kmem_cache_alloc+0x18d/0x2a0
[11138.458516]  btrfs_lookup_csums_range+0x149/0x4d0 [btrfs]
[11138.459407]  csum_exist_in_range+0x56/0x110 [btrfs]
[11138.460271]  can_nocow_file_extent+0x27c/0x310 [btrfs]
[11138.461155]  can_nocow_extent+0x1ec/0x2e0 [btrfs]
[11138.461672]  btrfs_check_nocow_lock+0x114/0x1c0 [btrfs]
[11138.462951]  btrfs_buffered_write+0x44c/0x8e0 [btrfs]
[11138.463482]  btrfs_do_write_iter+0x42b/0x5f0 [btrfs]
[11138.463982]  ? lock_release+0x153/0x4a0
[11138.464347]  io_write+0x11b/0x570
[11138.464660]  ? lock_release+0x153/0x4a0
[11138.465213]  ? lock_is_held_type+0xe8/0x140
[11138.466003]  io_issue_sqe+0x63/0x4a0
[11138.466339]  io_submit_sqes+0x238/0x770
[11138.466741]  __do_sys_io_uring_enter+0x37b/0xb10
[11138.467206]  ? lock_is_held_type+0xe8/0x140
[11138.467879]  ? syscall_enter_from_user_mode+0x1d/0x50
[11138.468688]  do_syscall_64+0x38/0x90
[11138.469265]  entry_SYSCALL_64_after_hwframe+0x63/0xcd
[11138.470017] RIP: 0033:0x7f1438c539e6

This is because to check if we can NOCOW, we check that if we can NOCOW
into an extent (it's prealloc extent or the inode has NOCOW attribute),
and then check if there are csums for the extent's range in the csum tree.
The search may leave us beyond the last slot of a leaf, and then when
we call btrfs_next_leaf() we end up at btrfs_next_old_leaf() with a
time_seq of 0.

This triggers a failure of the first assertion at btrfs_next_old_leaf(),
since we have a nowait path. With assertions disabled, we simply don't
respect the NOWAIT semantics, allowing the write to block on locks or
blocking on IO for reading an extent buffer from disk.

Fix this by:

1) Triggering the assertion only if time_seq is not 0, which means that
   search is being done by a tree mod log user, and in the buffered and
   direct IO write paths we don't use the tree mod log;

2) Implementing NOWAIT semantics at btrfs_next_old_leaf(). Any failure to
   lock an extent buffer should return immediately and not retry the
   search, as well as if we need to do IO to read an extent buffer from
   disk.

Fixes: c922b016f3 ("btrfs: assert nowait mode is not used for some btree search functions")
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-11-15 15:01:01 +01:00
Linus Torvalds
d7c2b1f64e 22 hotfixes. 8 are cc:stable and the remainder address issues which were
introduced post-6.0 or which aren't considered serious enough to justify a
 -stable backport.
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Merge tag 'mm-hotfixes-stable-2022-11-11' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull misc hotfixes from Andrew Morton:
 "22 hotfixes.

  Eight are cc:stable and the remainder address issues which were
  introduced post-6.0 or which aren't considered serious enough to
  justify a -stable backport"

* tag 'mm-hotfixes-stable-2022-11-11' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (22 commits)
  docs: kmsan: fix formatting of "Example report"
  mm/damon/dbgfs: check if rm_contexts input is for a real context
  maple_tree: don't set a new maximum on the node when not reusing nodes
  maple_tree: fix depth tracking in maple_state
  arch/x86/mm/hugetlbpage.c: pud_huge() returns 0 when using 2-level paging
  fs: fix leaked psi pressure state
  nilfs2: fix use-after-free bug of ns_writer on remount
  x86/traps: avoid KMSAN bugs originating from handle_bug()
  kmsan: make sure PREEMPT_RT is off
  Kconfig.debug: ensure early check for KMSAN in CONFIG_KMSAN_WARN
  x86/uaccess: instrument copy_from_user_nmi()
  kmsan: core: kmsan_in_runtime() should return true in NMI context
  mm: hugetlb_vmemmap: include missing linux/moduleparam.h
  mm/shmem: use page_mapping() to detect page cache for uffd continue
  mm/memremap.c: map FS_DAX device memory as decrypted
  Partly revert "mm/thp: carry over dirty bit when thp splits on pmd"
  nilfs2: fix deadlock in nilfs_count_free_blocks()
  mm/mmap: fix memory leak in mmap_region()
  hugetlbfs: don't delete error page from pagecache
  maple_tree: reorganize testing to restore module testing
  ...
2022-11-11 17:18:42 -08:00
Linus Torvalds
1767a722a7 for-6.1-rc4-tag
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Merge tag 'for-6.1-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux

Pull btrfs fixes from David Sterba:

 - revert memory optimization for scrub blocks, this misses errors in
   2nd and following blocks

 - add exception for ENOMEM as reason for transaction abort to not print
   stack trace, syzbot has reported many

 - zoned fixes:
      - fix locking imbalance during scrub
      - initialize zones for seeding device
      - initialize zones for cloned device structures

 - when looking up device, change assertion to a real check as some of
   the search parameters can be passed by ioctl, reported by syzbot

 - fix error pointer check in self tests

* tag 'for-6.1-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
  btrfs: zoned: fix locking imbalance on scrub
  btrfs: zoned: initialize device's zone info for seeding
  btrfs: zoned: clone zoned device info when cloning a device
  Revert "btrfs: scrub: use larger block size for data extent scrub"
  btrfs: don't print stack trace when transaction is aborted due to ENOMEM
  btrfs: selftests: fix wrong error check in btrfs_free_dummy_root()
  btrfs: fix match incorrectly in dev_args_match_device
2022-11-10 08:58:29 -08:00
Johannes Weiner
82e60d00b7 fs: fix leaked psi pressure state
When psi annotations were added to to btrfs compression reads, the psi
state tracking over add_ra_bio_pages and btrfs_submit_compressed_read was
faulty.  A pressure state, once entered, is never left.  This results in
incorrectly elevated pressure, which triggers OOM kills.

pflags record the *previous* memstall state when we enter a new one.  The
code tried to initialize pflags to 1, and then optimize the leave call
when we either didn't enter a memstall, or were already inside a nested
stall.  However, there can be multiple PageWorkingset pages in the bio, at
which point it's that path itself that enters repeatedly and overwrites
pflags.  This causes us to miss the exit.

Enter the stall only once if needed, then unwind correctly.

erofs has the same problem, fix that up too.  And move the memstall exit
past submit_bio() to restore submit accounting originally added by
b8e24a9300 ("block: annotate refault stalls from IO submission").

Link: https://lkml.kernel.org/r/Y2UHRqthNUwuIQGS@cmpxchg.org
Fixes: 4088a47e78 ("btrfs: add manual PSI accounting for compressed reads")
Fixes: 99486c511f ("erofs: add manual PSI accounting for the compressed address space")
Fixes: 118f3663fb ("block: remove PSI accounting from the bio layer")
Link: https://lore.kernel.org/r/d20a0a85-e415-cf78-27f9-77dd7a94bc8d@leemhuis.info/
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reported-by: Thorsten Leemhuis <linux@leemhuis.info>
Tested-by: Thorsten Leemhuis <linux@leemhuis.info>
Cc: Chao Yu <chao@kernel.org>
Cc: Chris Mason <clm@fb.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Sterba <dsterba@suse.com>
Cc: Gao Xiang <xiang@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Josef Bacik <josef@toxicpanda.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-11-08 15:57:25 -08:00
Johannes Thumshirn
c62f6bec53 btrfs: zoned: fix locking imbalance on scrub
If we're doing device replace on a zoned filesystem and discover in
scrub_enumerate_chunks() that we don't have to copy the block group it is
unlocked before it gets skipped.

But as the block group hasn't yet been locked before it leads to a locking
imbalance. To fix this simply remove the unlock.

This was uncovered by fstests' testcase btrfs/163.

Fixes: 9283b9e09a ("btrfs: remove lock protection for BLOCK_GROUP_FLAG_TO_COPY")
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-11-07 14:35:25 +01:00
Johannes Thumshirn
a8d1b1647b btrfs: zoned: initialize device's zone info for seeding
When performing seeding on a zoned filesystem it is necessary to
initialize each zoned device's btrfs_zoned_device_info structure,
otherwise mounting the filesystem will cause a NULL pointer dereference.

This was uncovered by fstests' testcase btrfs/163.

CC: stable@vger.kernel.org # 5.15+
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-11-07 14:35:24 +01:00
Johannes Thumshirn
21e61ec6d0 btrfs: zoned: clone zoned device info when cloning a device
When cloning a btrfs_device, we're not cloning the associated
btrfs_zoned_device_info structure of the device in case of a zoned
filesystem.

Later on this leads to a NULL pointer dereference when accessing the
device's zone_info for instance when setting a zone as active.

This was uncovered by fstests' testcase btrfs/161.

CC: stable@vger.kernel.org # 5.15+
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-11-07 14:35:21 +01:00
Qu Wenruo
b75b51f886 Revert "btrfs: scrub: use larger block size for data extent scrub"
This reverts commit 786672e9e1.

[BUG]
Since commit 786672e9e1 ("btrfs: scrub: use larger block size for data
extent scrub"), btrfs scrub no longer reports errors if the corruption
is not in the first sector of a STRIPE_LEN.

The following script can expose the problem:

  mkfs.btrfs -f $dev
  mount $dev $mnt
  xfs_io -f -c "pwrite -S 0xff 0 8k" $mnt/foobar
  umount $mnt

  # 13631488 is the logical bytenr of above 8K extent
  btrfs-map-logical -l 13631488 -b 4096 $dev
  mirror 1 logical 13631488 physical 13631488 device /dev/test/scratch1

  # Corrupt the 2nd sector of that extent
  xfs_io -f -c "pwrite -S 0x00 13635584 4k" $dev

  mount $dev $mnt
  btrfs scrub start -B $mnt
  scrub done for 54e63f9f-0c30-4c84-a33b-5c56014629b7
  Scrub started:    Mon Nov  7 07:18:27 2022
  Status:           finished
  Duration:         0:00:00
  Total to scrub:   536.00MiB
  Rate:             0.00B/s
  Error summary:    no errors found <<<

[CAUSE]
That offending commit enlarges the data extent scrub size from sector
size to BTRFS_STRIPE_LEN, to avoid extra scrub_block to be allocated.

But unfortunately the data extent scrub is still heavily relying on the
fact that there is only one scrub_sector per scrub_block.

Thus it will only check the first sector, and ignoring the remaining
sectors.

Furthermore the error reporting is not able to handle multiple sectors
either.

[FIX]
For now just revert the offending commit.

The consequence is just extra memory usage during scrub.
We will need a proper change to make the remaining data scrub path to
handle multiple sectors before we enlarging the data scrub size.

Reported-by: Li Zhang <zhanglikernel@gmail.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-11-07 14:35:14 +01:00
David Sterba
8bb808c6ad btrfs: don't print stack trace when transaction is aborted due to ENOMEM
Add ENOMEM among the error codes that don't print stack trace on
transaction abort. We've got several reports from syzbot that detects
stacks as errors but caused by limiting memory. As this is an artificial
condition we don't need to know where exactly the error happens, the
abort and error cleanup will continue like e.g. for EIO.

As the transaction aborts code needs to be inline in a lot of code, the
implementation cases about minimal bloat. The error codes are in a
separate function and the WARN uses the condition directly. This
increases the code size by 571 bytes on release build.

Alternatives considered: add -ENOMEM among the errors, this increases
size by 2340 bytes, various attempts to combine the WARN and helper
calls, increase by 700 or more bytes.

Example syzbot reports (error -12):

- https://syzkaller.appspot.com/bug?extid=5244d35be7f589cf093e
- https://syzkaller.appspot.com/bug?extid=9c37714c07194d816417

Signed-off-by: David Sterba <dsterba@suse.com>
2022-11-07 14:34:57 +01:00
Zhang Xiaoxu
9b2f20344d btrfs: selftests: fix wrong error check in btrfs_free_dummy_root()
The btrfs_alloc_dummy_root() uses ERR_PTR as the error return value
rather than NULL, if error happened, there will be a NULL pointer
dereference:

  BUG: KASAN: null-ptr-deref in btrfs_free_dummy_root+0x21/0x50 [btrfs]
  Read of size 8 at addr 000000000000002c by task insmod/258926

  CPU: 2 PID: 258926 Comm: insmod Tainted: G        W          6.1.0-rc2+ #5
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-1.fc33 04/01/2014
  Call Trace:
   <TASK>
   dump_stack_lvl+0x34/0x44
   kasan_report+0xb7/0x140
   kasan_check_range+0x145/0x1a0
   btrfs_free_dummy_root+0x21/0x50 [btrfs]
   btrfs_test_free_space_cache+0x1a8c/0x1add [btrfs]
   btrfs_run_sanity_tests+0x65/0x80 [btrfs]
   init_btrfs_fs+0xec/0x154 [btrfs]
   do_one_initcall+0x87/0x2a0
   do_init_module+0xdf/0x320
   load_module+0x3006/0x3390
   __do_sys_finit_module+0x113/0x1b0
   do_syscall_64+0x35/0x80
 entry_SYSCALL_64_after_hwframe+0x46/0xb0

Fixes: aaedb55bc0 ("Btrfs: add tests for btrfs_get_extent")
CC: stable@vger.kernel.org # 4.9+
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Zhang Xiaoxu <zhangxiaoxu5@huawei.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-11-07 14:30:50 +01:00
Liu Shixin
0fca385d6e btrfs: fix match incorrectly in dev_args_match_device
syzkaller found a failed assertion:

  assertion failed: (args->devid != (u64)-1) || args->missing, in fs/btrfs/volumes.c:6921

This can be triggered when we set devid to (u64)-1 by ioctl. In this
case, the match of devid will be skipped and the match of device may
succeed incorrectly.

Patch 562d7b1512 introduced this function which is used to match device.
This function contains two matching scenarios, we can distinguish them by
checking the value of args->missing rather than check whether args->devid
and args->uuid is default value.

Reported-by: syzbot+031687116258450f9853@syzkaller.appspotmail.com
Fixes: 562d7b1512 ("btrfs: handle device lookup with btrfs_dev_lookup_args")
CC: stable@vger.kernel.org # 5.16+
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Liu Shixin <liushixin2@huawei.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-11-07 14:30:45 +01:00
Linus Torvalds
f2f32f8af2 for-6.1-rc3-tag
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Merge tag 'for-6.1-rc3-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux

Pull btrfs fixes from David Sterba:
 "A batch of error handling fixes for resource leaks, fixes for nowait
  mode in combination with direct and buffered IO:

   - direct IO + dsync + nowait could miss a sync of the file after
     write, add handling for this combination

   - buffered IO + nowait should not fail with ENOSPC, only blocking IO
     could determine that

   - error handling fixes:
      - fix inode reserve space leak due to nowait buffered write
      - check the correct variable after allocation (direct IO submit)
      - fix inode list leak during backref walking
      - fix ulist freeing in self tests"

* tag 'for-6.1-rc3-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
  btrfs: fix inode reserve space leak due to nowait buffered write
  btrfs: fix nowait buffered write returning -ENOSPC
  btrfs: remove pointless and double ulist frees in error paths of qgroup tests
  btrfs: fix ulist leaks in error paths of qgroup self tests
  btrfs: fix inode list leak during backref walking at find_parent_nodes()
  btrfs: fix inode list leak during backref walking at resolve_indirect_refs()
  btrfs: fix lost file sync on direct IO write with nowait and dsync iocb
  btrfs: fix a memory allocation failure test in btrfs_submit_direct
2022-11-03 11:12:48 -07:00
Filipe Manana
eb81b682b1 btrfs: fix inode reserve space leak due to nowait buffered write
During a nowait buffered write, if we fail to balance dirty pages we exit
btrfs_buffered_write() without releasing the delalloc space reserved for
an extent, resulting in leaking space from the inode's block reserve.

So fix that by releasing the delalloc space for the extent when balancing
dirty pages fails.

Reported-by: kernel test robot <yujie.liu@intel.com>
Link: https://lore.kernel.org/all/202210111304.d369bc32-yujie.liu@intel.com
Fixes: 965f47aeb5 ("btrfs: make btrfs_buffered_write nowait compatible")
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-11-02 17:44:45 +01:00
Filipe Manana
a348c8d4f6 btrfs: fix nowait buffered write returning -ENOSPC
If we are doing a buffered write in NOWAIT context and we can't reserve
metadata space due to -ENOSPC, then we should return -EAGAIN so that we
retry the write in a context allowed to block and do metadata reservation
with flushing, which might succeed this time due to the allowed flushing.

Returning -ENOSPC while in NOWAIT context simply makes some writes fail
with -ENOSPC when they would likely succeed after switching from NOWAIT
context to blocking context. That is unexpected behaviour and even fio
complains about it with a warning like this:

  fio: io_u error on file /mnt/sdi/task_0.0.0: No space left on device: write offset=1535705088, buflen=65536
  fio: pid=592630, err=28/file:io_u.c:1846, func=io_u error, error=No space left on device

The fio's job config is this:

   [global]
   bs=64K
   ioengine=io_uring
   iodepth=1
   size=2236962133
   nr_files=1
   filesize=2236962133
   direct=0
   runtime=10
   fallocate=posix
   io_size=2236962133
   group_reporting
   time_based

   [task_0]
   rw=randwrite
   directory=/mnt/sdi
   numjobs=4

So fix this by returning -EAGAIN if we are in NOWAIT context and the
metadata reservation failed with -ENOSPC.

Fixes: 304e45acdb ("btrfs: plumb NOWAIT through the write path")
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-11-02 17:44:42 +01:00
Filipe Manana
d0ea17aec1 btrfs: remove pointless and double ulist frees in error paths of qgroup tests
Several places in the qgroup self tests follow the pattern of freeing the
ulist pointer they passed to btrfs_find_all_roots() if the call to that
function returned an error. That is pointless because that function always
frees the ulist in case it returns an error.

Also In some places like at test_multiple_refs(), after a call to
btrfs_qgroup_account_extent() we also leave "old_roots" and "new_roots"
pointing to ulists that were freed, because btrfs_qgroup_account_extent()
has freed those ulists, and if after that the next call to
btrfs_find_all_roots() fails, we call ulist_free() on the "old_roots"
ulist again, resulting in a double free.

So remove those calls to reduce the code size and avoid double ulist
free in case of an error.

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-11-02 17:44:30 +01:00
Filipe Manana
d37de92b38 btrfs: fix ulist leaks in error paths of qgroup self tests
In the test_no_shared_qgroup() and test_multiple_refs() qgroup self tests,
if we fail to add the tree ref, remove the extent item or remove the
extent ref, we are returning from the test function without freeing the
"old_roots" ulist that was allocated by the previous calls to
btrfs_find_all_roots(). Fix that by calling ulist_free() before returning.

Fixes: 442244c963 ("btrfs: qgroup: Switch self test to extent-oriented qgroup mechanism.")
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-11-02 17:43:32 +01:00
Filipe Manana
92876eec38 btrfs: fix inode list leak during backref walking at find_parent_nodes()
During backref walking, at find_parent_nodes(), if we are dealing with a
data extent and we get an error while resolving the indirect backrefs, at
resolve_indirect_refs(), or in the while loop that iterates over the refs
in the direct refs rbtree, we end up leaking the inode lists attached to
the direct refs we have in the direct refs rbtree that were not yet added
to the refs ulist passed as argument to find_parent_nodes(). Since they
were not yet added to the refs ulist and prelim_release() does not free
the lists, on error the caller can only free the lists attached to the
refs that were added to the refs ulist, all the remaining refs get their
inode lists never freed, therefore leaking their memory.

Fix this by having prelim_release() always free any attached inode list
to each ref found in the rbtree, and have find_parent_nodes() set the
ref's inode list to NULL once it transfers ownership of the inode list
to a ref added to the refs ulist passed to find_parent_nodes().

Fixes: 86d5f99442 ("btrfs: convert prelimary reference tracking to use rbtrees")
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-11-02 17:43:28 +01:00
Filipe Manana
5614dc3a47 btrfs: fix inode list leak during backref walking at resolve_indirect_refs()
During backref walking, at resolve_indirect_refs(), if we get an error
we jump to the 'out' label and call ulist_free() on the 'parents' ulist,
which frees all the elements in the ulist - however that does not free
any inode lists that may be attached to elements, through the 'aux' field
of a ulist node, so we end up leaking lists if we have any attached to
the unodes.

Fix this by calling free_leaf_list() instead of ulist_free() when we exit
from resolve_indirect_refs(). The static function free_leaf_list() is
moved up for this to be possible and it's slightly simplified by removing
unnecessary code.

Fixes: 3301958b7c ("Btrfs: add inodes before dropping the extent lock in find_all_leafs")
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-11-02 17:43:25 +01:00
Linus Torvalds
5aaef24b5c for-6.1-rc3-tag
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Merge tag 'for-6.1-rc3-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux

Pull btrfs fixes from David Sterba:
 "A few more fixes and regression fixes:

   - fix a corner case when handling tree-mod-log chagnes in reallocated
     notes

   - fix crash on raid0 filesystems created with <5.4 mkfs.btrfs that
     could lead to division by zero

   - add missing super block checksum verification after thawing
     filesystem

   - handle one more case in send when dealing with orphan files

   - fix parameter type mismatch for generation when reading dentry

   - improved error handling in raid56 code

   - better struct bio packing after recent cleanups"

* tag 'for-6.1-rc3-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
  btrfs: don't use btrfs_chunk::sub_stripes from disk
  btrfs: fix type of parameter generation in btrfs_get_dentry
  btrfs: send: fix send failure of a subcase of orphan inodes
  btrfs: make thaw time super block check to also verify checksum
  btrfs: fix tree mod log mishandling of reallocated nodes
  btrfs: reorder btrfs_bio for better packing
  btrfs: raid56: avoid double freeing for rbio if full_stripe_write() failed
  btrfs: raid56: properly handle the error when unable to find the missing stripe
2022-10-31 12:28:29 -07:00
Filipe Manana
8184620ae2 btrfs: fix lost file sync on direct IO write with nowait and dsync iocb
When doing a direct IO write using a iocb with nowait and dsync set, we
end up not syncing the file once the write completes.

This is because we tell iomap to not call generic_write_sync(), which
would result in calling btrfs_sync_file(), in order to avoid a deadlock
since iomap can call it while we are holding the inode's lock and
btrfs_sync_file() needs to acquire the inode's lock. The deadlock happens
only if the write happens synchronously, when iomap_dio_rw() calls
iomap_dio_complete() before it returns. Instead we do the sync ourselves
at btrfs_do_write_iter().

For a nowait write however we can end up not doing the sync ourselves at
at btrfs_do_write_iter() because the write could have been queued, and
therefore we get -EIOCBQUEUED returned from iomap in such case. That makes
us skip the sync call at btrfs_do_write_iter(), as we don't do it for
any error returned from btrfs_direct_write(). We can't simply do the call
even if -EIOCBQUEUED is returned, since that would block the task waiting
for IO, both for the data since there are bios still in progress as well
as potentially blocking when joining a log transaction and when syncing
the log (writing log trees, super blocks, etc).

So let iomap do the sync call itself and in order to avoid deadlocks for
the case of synchronous writes (without nowait), use __iomap_dio_rw() and
have ourselves call iomap_dio_complete() after unlocking the inode.

A test case will later be sent for fstests, after this is fixed in Linus'
tree.

Fixes: 51bd9563b6 ("btrfs: fix deadlock due to page faults during direct IO reads and writes")
Reported-by: Марк Коренберг <socketpair@gmail.com>
Link: https://lore.kernel.org/linux-btrfs/CAEmTpZGRKbzc16fWPvxbr6AfFsQoLmz-Lcg-7OgJOZDboJ+SGQ@mail.gmail.com/
CC: stable@vger.kernel.org # 6.0+
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-10-31 16:52:56 +01:00
Christophe JAILLET
063b1f21cc btrfs: fix a memory allocation failure test in btrfs_submit_direct
After allocation 'dip' is tested instead of 'dip->csums'.  Fix it.

Fixes: 642c5d34da ("btrfs: allocate the btrfs_dio_private as part of the iomap dio bio")
CC: stable@vger.kernel.org # 5.19+
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-10-31 16:50:15 +01:00
Qu Wenruo
76a66ba101 btrfs: don't use btrfs_chunk::sub_stripes from disk
[BUG]
There are two reports (the earliest one from LKP, a more recent one from
kernel bugzilla) that we can have some chunks with 0 as sub_stripes.

This will cause divide-by-zero errors at btrfs_rmap_block, which is
introduced by a recent kernel patch ac0677348f ("btrfs: merge
calculations for simple striped profiles in btrfs_rmap_block"):

		if (map->type & (BTRFS_BLOCK_GROUP_RAID0 |
				 BTRFS_BLOCK_GROUP_RAID10)) {
			stripe_nr = stripe_nr * map->num_stripes + i;
			stripe_nr = div_u64(stripe_nr, map->sub_stripes); <<<
		}

[CAUSE]
From the more recent report, it has been proven that we have some chunks
with 0 as sub_stripes, mostly caused by older mkfs.

It turns out that the mkfs.btrfs fix is only introduced in 6718ab4d33aa
("btrfs-progs: Initialize sub_stripes to 1 in btrfs_alloc_data_chunk")
which is included in v5.4 btrfs-progs release.

So there would be quite some old filesystems with such 0 sub_stripes.

[FIX]
Just don't trust the sub_stripes values from disk.

We have a trusted btrfs_raid_array[] to fetch the correct sub_stripes
numbers for each profile and that are fixed.

By this, we can keep the compatibility with older filesystems while
still avoid divide-by-zero bugs.

Reported-by: kernel test robot <oliver.sang@intel.com>
Reported-by: Viktor Kuzmin <kvaster@gmail.com>
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=216559
Fixes: ac0677348f ("btrfs: merge calculations for simple striped profiles in btrfs_rmap_block")
CC: stable@vger.kernel.org # 6.0
Reviewed-by: Su Yue <glass@fydeos.io>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-10-25 10:17:33 +02:00
David Sterba
2398091f9c btrfs: fix type of parameter generation in btrfs_get_dentry
The type of parameter generation has been u32 since the beginning,
however all callers pass a u64 generation, so unify the types to prevent
potential loss.

CC: stable@vger.kernel.org # 4.9+
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-10-24 15:28:58 +02:00
BingJing Chang
9b8be45f1e btrfs: send: fix send failure of a subcase of orphan inodes
Commit 9ed0a72e5b ("btrfs: send: fix failures when processing inodes with
no links") tries to fix all incremental send cases of orphan inodes the
send operation will meet. However, there's still a bug causing the corner
subcase fails with a ENOENT error.

Here's shortened steps of that subcase:

  $ btrfs subvolume create vol
  $ touch vol/foo

  $ btrfs subvolume snapshot -r vol snap1
  $ btrfs subvolume snapshot -r vol snap2

  # Turn the second snapshot to RW mode and delete the file while
  # holding an open file descriptor on it
  $ btrfs property set snap2 ro false
  $ exec 73<snap2/foo
  $ rm snap2/foo

  # Set the second snapshot back to RO mode and do an incremental send
  # with an unusal reverse order
  $ btrfs property set snap2 ro true
  $ btrfs send -p snap2 snap1 > /dev/null
  At subvol snap1
  ERROR: send ioctl failed with -2: No such file or directory

It's subcase 3 of BTRFS_COMPARE_TREE_CHANGED in the commit 9ed0a72e5b
("btrfs: send: fix failures when processing inodes with no links"). And
it's not a common case. We still have not met it in the real world.
Theoretically, this case can happen in a batch cascading snapshot backup.
In cascading backups, the receive operation in the middle may cause orphan
inodes to appear because of the open file descriptors on the snapshot files
during receiving. And if we don't do the batch snapshot backups in their
creation order, then we can have an inode, which is an orphan in the parent
snapshot but refers to a file in the send snapshot. Since an orphan inode
has no paths, the send operation will fail with a ENOENT error if it
tries to generate a path for it.

In that patch, this subcase will be treated as an inode with a new
generation. However, when the routine tries to delete the old paths in
the parent snapshot, the function process_all_refs() doesn't check whether
there are paths recorded or not before it calls the function
process_recorded_refs(). And the function process_recorded_refs() try
to get the first path in the parent snapshot in the beginning. Since it has
no paths in the parent snapshot, the send operation fails.

To fix this, we can easily put a link count check to avoid entering the
deletion routine like what we do a link count check to avoid creating a
new one. Moreover, we can assume that the function process_all_refs()
can always collect references to process because we know it has a
positive link count.

Fixes: 9ed0a72e5b ("btrfs: send: fix failures when processing inodes with no links")
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: BingJing Chang <bingjingc@synology.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-10-24 15:28:52 +02:00
Qu Wenruo
3d17adea74 btrfs: make thaw time super block check to also verify checksum
Previous commit a05d3c9153 ("btrfs: check superblock to ensure the fs
was not modified at thaw time") only checks the content of the super
block, but it doesn't really check if the on-disk super block has a
matching checksum.

This patch will add the checksum verification to thaw time superblock
verification.

This involves the following extra changes:

- Export btrfs_check_super_csum()
  As we need to call it in super.c.

- Change the argument list of btrfs_check_super_csum()
  Instead of passing a char *, directly pass struct btrfs_super_block *
  pointer.

- Verify that our checksum type didn't change before checking the
  checksum value, like it's done at mount time

Fixes: a05d3c9153 ("btrfs: check superblock to ensure the fs was not modified at thaw time")
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-10-24 15:28:29 +02:00
Josef Bacik
968b715831 btrfs: fix tree mod log mishandling of reallocated nodes
We have been seeing the following panic in production

  kernel BUG at fs/btrfs/tree-mod-log.c:677!
  invalid opcode: 0000 [#1] SMP
  RIP: 0010:tree_mod_log_rewind+0x1b4/0x200
  RSP: 0000:ffffc9002c02f890 EFLAGS: 00010293
  RAX: 0000000000000003 RBX: ffff8882b448c700 RCX: 0000000000000000
  RDX: 0000000000008000 RSI: 00000000000000a7 RDI: ffff88877d831c00
  RBP: 0000000000000002 R08: 000000000000009f R09: 0000000000000000
  R10: 0000000000000000 R11: 0000000000100c40 R12: 0000000000000001
  R13: ffff8886c26d6a00 R14: ffff88829f5424f8 R15: ffff88877d831a00
  FS:  00007fee1d80c780(0000) GS:ffff8890400c0000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: 00007fee1963a020 CR3: 0000000434f33002 CR4: 00000000007706e0
  DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
  DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
  PKRU: 55555554
  Call Trace:
   btrfs_get_old_root+0x12b/0x420
   btrfs_search_old_slot+0x64/0x2f0
   ? tree_mod_log_oldest_root+0x3d/0xf0
   resolve_indirect_ref+0xfd/0x660
   ? ulist_alloc+0x31/0x60
   ? kmem_cache_alloc_trace+0x114/0x2c0
   find_parent_nodes+0x97a/0x17e0
   ? ulist_alloc+0x30/0x60
   btrfs_find_all_roots_safe+0x97/0x150
   iterate_extent_inodes+0x154/0x370
   ? btrfs_search_path_in_tree+0x240/0x240
   iterate_inodes_from_logical+0x98/0xd0
   ? btrfs_search_path_in_tree+0x240/0x240
   btrfs_ioctl_logical_to_ino+0xd9/0x180
   btrfs_ioctl+0xe2/0x2ec0
   ? __mod_memcg_lruvec_state+0x3d/0x280
   ? do_sys_openat2+0x6d/0x140
   ? kretprobe_dispatcher+0x47/0x70
   ? kretprobe_rethook_handler+0x38/0x50
   ? rethook_trampoline_handler+0x82/0x140
   ? arch_rethook_trampoline_callback+0x3b/0x50
   ? kmem_cache_free+0xfb/0x270
   ? do_sys_openat2+0xd5/0x140
   __x64_sys_ioctl+0x71/0xb0
   do_syscall_64+0x2d/0x40

Which is this code in tree_mod_log_rewind()

	switch (tm->op) {
        case BTRFS_MOD_LOG_KEY_REMOVE_WHILE_FREEING:
		BUG_ON(tm->slot < n);

This occurs because we replay the nodes in order that they happened, and
when we do a REPLACE we will log a REMOVE_WHILE_FREEING for every slot,
starting at 0.  'n' here is the number of items in this block, which in
this case was 1, but we had 2 REMOVE_WHILE_FREEING operations.

The actual root cause of this was that we were replaying operations for
a block that shouldn't have been replayed.  Consider the following
sequence of events

1. We have an already modified root, and we do a btrfs_get_tree_mod_seq().
2. We begin removing items from this root, triggering KEY_REPLACE for
   it's child slots.
3. We remove one of the 2 children this root node points to, thus triggering
   the root node promotion of the remaining child, and freeing this node.
4. We modify a new root, and re-allocate the above node to the root node of
   this other root.

The tree mod log looks something like this

	logical 0	op KEY_REPLACE (slot 1)			seq 2
	logical 0	op KEY_REMOVE (slot 1)			seq 3
	logical 0	op KEY_REMOVE_WHILE_FREEING (slot 0)	seq 4
	logical 4096	op LOG_ROOT_REPLACE (old logical 0)	seq 5
	logical 8192	op KEY_REMOVE_WHILE_FREEING (slot 1)	seq 6
	logical 8192	op KEY_REMOVE_WHILE_FREEING (slot 0)	seq 7
	logical 0	op LOG_ROOT_REPLACE (old logical 8192)	seq 8

>From here the bug is triggered by the following steps

1.  Call btrfs_get_old_root() on the new_root.
2.  We call tree_mod_log_oldest_root(btrfs_root_node(new_root)), which is
    currently logical 0.
3.  tree_mod_log_oldest_root() calls tree_mod_log_search_oldest(), which
    gives us the KEY_REPLACE seq 2, and since that's not a
    LOG_ROOT_REPLACE we incorrectly believe that we don't have an old
    root, because we expect that the most recent change should be a
    LOG_ROOT_REPLACE.
4.  Back in tree_mod_log_oldest_root() we don't have a LOG_ROOT_REPLACE,
    so we don't set old_root, we simply use our existing extent buffer.
5.  Since we're using our existing extent buffer (logical 0) we call
    tree_mod_log_search(0) in order to get the newest change to start the
    rewind from, which ends up being the LOG_ROOT_REPLACE at seq 8.
6.  Again since we didn't find an old_root we simply clone logical 0 at
    it's current state.
7.  We call tree_mod_log_rewind() with the cloned extent buffer.
8.  Set n = btrfs_header_nritems(logical 0), which would be whatever the
    original nritems was when we COWed the original root, say for this
    example it's 2.
9.  We start from the newest operation and work our way forward, so we
    see LOG_ROOT_REPLACE which we ignore.
10. Next we see KEY_REMOVE_WHILE_FREEING for slot 0, which triggers the
    BUG_ON(tm->slot < n), because it expects if we've done this we have a
    completely empty extent buffer to replay completely.

The correct thing would be to find the first LOG_ROOT_REPLACE, and then
get the old_root set to logical 8192.  In fact making that change fixes
this particular problem.

However consider the much more complicated case.  We have a child node
in this tree and the above situation.  In the above case we freed one
of the child blocks at the seq 3 operation.  If this block was also
re-allocated and got new tree mod log operations we would have a
different problem.  btrfs_search_old_slot(orig root) would get down to
the logical 0 root that still pointed at that node.  However in
btrfs_search_old_slot() we call tree_mod_log_rewind(buf) directly.  This
is not context aware enough to know which operations we should be
replaying.  If the block was re-allocated multiple times we may only
want to replay a range of operations, and determining what that range is
isn't possible to determine.

We could maybe solve this by keeping track of which root the node
belonged to at every tree mod log operation, and then passing this
around to make sure we're only replaying operations that relate to the
root we're trying to rewind.

However there's a simpler way to solve this problem, simply disallow
reallocations if we have currently running tree mod log users.  We
already do this for leaf's, so we're simply expanding this to nodes as
well.  This is a relatively uncommon occurrence, and the problem is
complicated enough I'm worried that we will still have corner cases in
the reallocation case.  So fix this in the most straightforward way
possible.

Fixes: bd989ba359 ("Btrfs: add tree modification log functions")
CC: stable@vger.kernel.org # 3.3+
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-10-24 15:28:07 +02:00
David Sterba
ae0e5df4d1 btrfs: reorder btrfs_bio for better packing
After changes in commit 917f32a235 ("btrfs: give struct btrfs_bio a
real end_io handler") the layout of btrfs_bio can be improved.  There
are two holes and the structure size is 264 bytes on release build. By
reordering the iterator we can get rid of the holes and the size is 256
bytes which fits to slabs much better.

Final layout:

struct btrfs_bio {
	unsigned int               mirror_num;           /*     0     4 */
	struct bvec_iter           iter;                 /*     4    20 */
	u64                        file_offset;          /*    24     8 */
	struct btrfs_device *      device;               /*    32     8 */
	u8 *                       csum;                 /*    40     8 */
	u8                         csum_inline[64];      /*    48    64 */
	/* --- cacheline 1 boundary (64 bytes) was 48 bytes ago --- */
	btrfs_bio_end_io_t         end_io;               /*   112     8 */
	void *                     private;              /*   120     8 */
	/* --- cacheline 2 boundary (128 bytes) --- */
	struct work_struct         end_io_work;          /*   128    32 */
	struct bio                 bio;                  /*   160    96 */

	/* size: 256, cachelines: 4, members: 10 */
};

Fixes: 917f32a235 ("btrfs: give struct btrfs_bio a real end_io handler")
Signed-off-by: David Sterba <dsterba@suse.com>
2022-10-24 15:27:34 +02:00
Qu Wenruo
ab4c54c643 btrfs: raid56: avoid double freeing for rbio if full_stripe_write() failed
Currently if full_stripe_write() failed to allocate the pages for
parity, it will call __free_raid_bio() first, then return -ENOMEM.

But some caller of full_stripe_write() will also call __free_raid_bio()
again, this would cause double freeing.

And it's not a logically sound either, normally we should either free
the memory at the same level where we allocated it, or let endio to
handle everything.

So this patch will solve the double freeing by make
raid56_parity_write() to handle the error and free the rbio.

Just like what we do in raid56_parity_recover().

Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-10-24 15:26:56 +02:00
Qu Wenruo
f15fb2cd97 btrfs: raid56: properly handle the error when unable to find the missing stripe
In raid56_alloc_missing_rbio(), if we can not determine where the
missing device is inside the full stripe, we just BUG_ON().

This is not necessary especially the only caller inside scrub.c is
already properly checking the return value, and will treat it as a
memory allocation failure.

Fix the error handling by:

- Add an extra warning for the reason
  Although personally speaking it may be better to be an ASSERT().

- Properly free the allocated rbio

Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-10-24 15:26:54 +02:00
Linus Torvalds
aae703b02f for-6.1-rc1-tag
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Merge tag 'for-6.1-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux

Pull btrfs fixes from David Sterba:

 - fiemap fixes:
      - add missing path cache update
      - fix processing of delayed data and tree refs during backref
        walking, this could lead to reporting incorrect extent sharing

 - fix extent range locking under heavy contention to avoid deadlocks

 - make it possible to test send v3 in debugging mode

 - update links in MAINTAINERS

* tag 'for-6.1-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
  MAINTAINERS: update btrfs website links and files
  btrfs: ignore fiemap path cache if we have multiple leaves for a data extent
  btrfs: fix processing of delayed tree block refs during backref walking
  btrfs: fix processing of delayed data refs during backref walking
  btrfs: delete stale comments after merge conflict resolution
  btrfs: unlock locked extent area if we have contention
  btrfs: send: update command for protocol version check
  btrfs: send: allow protocol version 3 with CONFIG_BTRFS_DEBUG
  btrfs: add missing path cache update during fiemap
2022-10-18 11:25:50 -07:00
Filipe Manana
63c84b46b3 btrfs: ignore fiemap path cache if we have multiple leaves for a data extent
The path cache used during fiemap used to determine the sharedness of
extent buffers in a path from a leaf containing a file extent item
pointing to our data extent up to the root node of the tree, is meant to
be used for a single path. Having a single path is by far the most common
case, and therefore worth to optimize for, but it's possible to actually
have multiple paths because we have 2 or more leaves.

If we have multiple leaves, the 'level' variable keeps getting incremented
in each iteration of the while loop at btrfs_is_data_extent_shared(),
which means we will treat the second leaf in the 'tmp' ulist as a level 1
node, and so forth. In the worst case this can lead to getting a level
greater than or equals to BTRFS_MAX_LEVEL (8), which will trigger a
WARN_ON_ONCE() in the functions to lookup from or store in the path cache
(lookup_backref_shared_cache() and store_backref_shared_cache()). If the
current level never goes beyond 8, due to shared nodes in the paths and
a fs tree height smaller than 8, it can still result in incorrectly
marking one leaf as shared because some other leaf is shared and is stored
one level below that other leaf, as when storing a true sharedness value
in the cache results in updating the sharedness to true of all entries in
the cache below the current level.

Having multiple leaves happens in a case like the following:

  - We have a file extent item point to data extent at bytenr X, for
    a file range [0, 1M[ for example;

  - At this moment we have an extent data ref for the extent, with
    an offset of 0 and a count of 1;

  - A write into the middle of the extent happens, file range [64K, 128K)
    so the file extent item is split into two (at btrfs_drop_extents()):

    1) One for file range [0, 64K), with a length (num_bytes field) of
       64K and an extent offset of 0;

    2) Another one for file range [128K, 1M), with a length of 896K
       (1M - 128K) and an extent offset of 128K.

  - At this moment the two file extent items are located in the same
    leaf;

  - A new file extent item for the range [64K, 128K), pointing to a new
    data extent, is inserted in the leaf. This results in a leaf split
    and now those two file extent items pointing to data extent X end
    up located in different leaves;

  - Once delayed refs are run, we still have a single extent data ref
    item for our data extent at bytenr X, for offset 0, but now with a
    count of 2 instead of 1;

  - So during fiemap, at btrfs_is_data_extent_shared(), after we call
    find_parent_nodes() for the data extent, we get two leaves, since
    we have two file extent items point to data extent at bytenr X that
    are located in two different leaves.

So skip the use of the path cache when we get more than one leaf.

Fixes: 12a824dc67 ("btrfs: speedup checking for extent sharedness during fiemap")
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-10-11 14:48:07 +02:00
Filipe Manana
943553ef9b btrfs: fix processing of delayed tree block refs during backref walking
During backref walking, when processing a delayed reference with a type of
BTRFS_TREE_BLOCK_REF_KEY, we have two bugs there:

1) We are accessing the delayed references extent_op, and its key, without
   the protection of the delayed ref head's lock;

2) If there's no extent op for the delayed ref head, we end up with an
   uninitialized key in the stack, variable 'tmp_op_key', and then pass
   it to add_indirect_ref(), which adds the reference to the indirect
   refs rb tree.

   This is wrong, because indirect references should have a NULL key
   when we don't have access to the key, and in that case they should be
   added to the indirect_missing_keys rb tree and not to the indirect rb
   tree.

   This means that if have BTRFS_TREE_BLOCK_REF_KEY delayed ref resulting
   from freeing an extent buffer, therefore with a count of -1, it will
   not cancel out the corresponding reference we have in the extent tree
   (with a count of 1), since both references end up in different rb
   trees.

   When using fiemap, where we often need to check if extents are shared
   through shared subtrees resulting from snapshots, it means we can
   incorrectly report an extent as shared when it's no longer shared.
   However this is temporary because after the transaction is committed
   the extent is no longer reported as shared, as running the delayed
   reference results in deleting the tree block reference from the extent
   tree.

   Outside the fiemap context, the result is unpredictable, as the key was
   not initialized but it's used when navigating the rb trees to insert
   and search for references (prelim_ref_compare()), and we expect all
   references in the indirect rb tree to have valid keys.

The following reproducer triggers the second bug:

   $ cat test.sh
   #!/bin/bash

   DEV=/dev/sdj
   MNT=/mnt/sdj

   mkfs.btrfs -f $DEV
   mount -o compress $DEV $MNT

   # With a compressed 128M file we get a tree height of 2 (level 1 root).
   xfs_io -f -c "pwrite -b 1M 0 128M" $MNT/foo

   btrfs subvolume snapshot $MNT $MNT/snap

   # Fiemap should output 0x2008 in the flags column.
   # 0x2000 means shared extent
   # 0x8 means encoded extent (because it's compressed)
   echo
   echo "fiemap after snapshot, range [120M, 120M + 128K):"
   xfs_io -c "fiemap -v 120M 128K" $MNT/foo
   echo

   # Overwrite one extent and fsync to flush delalloc and COW a new path
   # in the snapshot's tree.
   #
   # After this we have a BTRFS_DROP_DELAYED_REF delayed ref of type
   # BTRFS_TREE_BLOCK_REF_KEY with a count of -1 for every COWed extent
   # buffer in the path.
   #
   # In the extent tree we have inline references of type
   # BTRFS_TREE_BLOCK_REF_KEY, with a count of 1, for the same extent
   # buffers, so they should cancel each other, and the extent buffers in
   # the fs tree should no longer be considered as shared.
   #
   echo "Overwriting file range [120M, 120M + 128K)..."
   xfs_io -c "pwrite -b 128K 120M 128K" $MNT/snap/foo
   xfs_io -c "fsync" $MNT/snap/foo

   # Fiemap should output 0x8 in the flags column. The extent in the range
   # [120M, 120M + 128K) is no longer shared, it's now exclusive to the fs
   # tree.
   echo
   echo "fiemap after overwrite range [120M, 120M + 128K):"
   xfs_io -c "fiemap -v 120M 128K" $MNT/foo
   echo

   umount $MNT

Running it before this patch:

   $ ./test.sh
   (...)
   wrote 134217728/134217728 bytes at offset 0
   128 MiB, 128 ops; 0.1152 sec (1.085 GiB/sec and 1110.5809 ops/sec)
   Create a snapshot of '/mnt/sdj' in '/mnt/sdj/snap'

   fiemap after snapshot, range [120M, 120M + 128K):
   /mnt/sdj/foo:
    EXT: FILE-OFFSET      BLOCK-RANGE      TOTAL FLAGS
      0: [245760..246015]: 34304..34559       256 0x2008

   Overwriting file range [120M, 120M + 128K)...
   wrote 131072/131072 bytes at offset 125829120
   128 KiB, 1 ops; 0.0001 sec (683.060 MiB/sec and 5464.4809 ops/sec)

   fiemap after overwrite range [120M, 120M + 128K):
   /mnt/sdj/foo:
    EXT: FILE-OFFSET      BLOCK-RANGE      TOTAL FLAGS
      0: [245760..246015]: 34304..34559       256 0x2008

The extent in the range [120M, 120M + 128K) is still reported as shared
(0x2000 bit set) after overwriting that range and flushing delalloc, which
is not correct - an entire path was COWed in the snapshot's tree and the
extent is now only referenced by the original fs tree.

Running it after this patch:

   $ ./test.sh
   (...)
   wrote 134217728/134217728 bytes at offset 0
   128 MiB, 128 ops; 0.1198 sec (1.043 GiB/sec and 1068.2067 ops/sec)
   Create a snapshot of '/mnt/sdj' in '/mnt/sdj/snap'

   fiemap after snapshot, range [120M, 120M + 128K):
   /mnt/sdj/foo:
    EXT: FILE-OFFSET      BLOCK-RANGE      TOTAL FLAGS
      0: [245760..246015]: 34304..34559       256 0x2008

   Overwriting file range [120M, 120M + 128K)...
   wrote 131072/131072 bytes at offset 125829120
   128 KiB, 1 ops; 0.0001 sec (694.444 MiB/sec and 5555.5556 ops/sec)

   fiemap after overwrite range [120M, 120M + 128K):
   /mnt/sdj/foo:
    EXT: FILE-OFFSET      BLOCK-RANGE      TOTAL FLAGS
      0: [245760..246015]: 34304..34559       256   0x8

Now the extent is not reported as shared anymore.

So fix this by passing a NULL key pointer to add_indirect_ref() when
processing a delayed reference for a tree block if there's no extent op
for our delayed ref head with a defined key. Also access the extent op
only after locking the delayed ref head's lock.

The reproducer will be converted later to a test case for fstests.

Fixes: 86d5f99442 ("btrfs: convert prelimary reference tracking to use rbtrees")
Fixes: a6dbceafb9 ("btrfs: Remove unused op_key var from add_delayed_refs")
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-10-11 14:48:01 +02:00
Filipe Manana
4fc7b57228 btrfs: fix processing of delayed data refs during backref walking
When processing delayed data references during backref walking and we are
using a share context (we are being called through fiemap), whenever we
find a delayed data reference for an inode different from the one we are
interested in, then we immediately exit and consider the data extent as
shared. This is wrong, because:

1) This might be a DROP reference that will cancel out a reference in the
   extent tree;

2) Even if it's an ADD reference, it may be followed by a DROP reference
   that cancels it out.

In either case we should not exit immediately.

Fix this by never exiting when we find a delayed data reference for
another inode - instead add the reference and if it does not cancel out
other delayed reference, we will exit early when we call
extent_is_shared() after processing all delayed references. If we find
a drop reference, then signal the code that processes references from
the extent tree (add_inline_refs() and add_keyed_refs()) to not exit
immediately if it finds there a reference for another inode, since we
have delayed drop references that may cancel it out. In this later case
we exit once we don't have references in the rb trees that cancel out
each other and have two references for different inodes.

Example reproducer for case 1):

   $ cat test-1.sh
   #!/bin/bash

   DEV=/dev/sdj
   MNT=/mnt/sdj

   mkfs.btrfs -f $DEV
   mount $DEV $MNT

   xfs_io -f -c "pwrite 0 64K" $MNT/foo
   cp --reflink=always $MNT/foo $MNT/bar

   echo
   echo "fiemap after cloning:"
   xfs_io -c "fiemap -v" $MNT/foo

   rm -f $MNT/bar
   echo
   echo "fiemap after removing file bar:"
   xfs_io -c "fiemap -v" $MNT/foo

   umount $MNT

Running it before this patch, the extent is still listed as shared, it has
the flag 0x2000 (FIEMAP_EXTENT_SHARED) set:

   $ ./test-1.sh
   fiemap after cloning:
   /mnt/sdj/foo:
    EXT: FILE-OFFSET      BLOCK-RANGE      TOTAL FLAGS
      0: [0..127]:        26624..26751       128 0x2001

   fiemap after removing file bar:
   /mnt/sdj/foo:
    EXT: FILE-OFFSET      BLOCK-RANGE      TOTAL FLAGS
      0: [0..127]:        26624..26751       128 0x2001

Example reproducer for case 2):

   $ cat test-2.sh
   #!/bin/bash

   DEV=/dev/sdj
   MNT=/mnt/sdj

   mkfs.btrfs -f $DEV
   mount $DEV $MNT

   xfs_io -f -c "pwrite 0 64K" $MNT/foo
   cp --reflink=always $MNT/foo $MNT/bar

   # Flush delayed references to the extent tree and commit current
   # transaction.
   sync

   echo
   echo "fiemap after cloning:"
   xfs_io -c "fiemap -v" $MNT/foo

   rm -f $MNT/bar
   echo
   echo "fiemap after removing file bar:"
   xfs_io -c "fiemap -v" $MNT/foo

   umount $MNT

Running it before this patch, the extent is still listed as shared, it has
the flag 0x2000 (FIEMAP_EXTENT_SHARED) set:

   $ ./test-2.sh
   fiemap after cloning:
   /mnt/sdj/foo:
    EXT: FILE-OFFSET      BLOCK-RANGE      TOTAL FLAGS
      0: [0..127]:        26624..26751       128 0x2001

   fiemap after removing file bar:
   /mnt/sdj/foo:
    EXT: FILE-OFFSET      BLOCK-RANGE      TOTAL FLAGS
      0: [0..127]:        26624..26751       128 0x2001

After this patch, after deleting bar in both tests, the extent is not
reported with the 0x2000 flag anymore, it gets only the flag 0x1
(which is FIEMAP_EXTENT_LAST):

   $ ./test-1.sh
   fiemap after cloning:
   /mnt/sdj/foo:
    EXT: FILE-OFFSET      BLOCK-RANGE      TOTAL FLAGS
      0: [0..127]:        26624..26751       128 0x2001

   fiemap after removing file bar:
   /mnt/sdj/foo:
    EXT: FILE-OFFSET      BLOCK-RANGE      TOTAL FLAGS
      0: [0..127]:        26624..26751       128   0x1

   $ ./test-2.sh
   fiemap after cloning:
   /mnt/sdj/foo:
    EXT: FILE-OFFSET      BLOCK-RANGE      TOTAL FLAGS
      0: [0..127]:        26624..26751       128 0x2001

   fiemap after removing file bar:
   /mnt/sdj/foo:
    EXT: FILE-OFFSET      BLOCK-RANGE      TOTAL FLAGS
      0: [0..127]:        26624..26751       128   0x1

These tests will later be converted to a test case for fstests.

Fixes: dc046b10c8 ("Btrfs: make fiemap not blow when you have lots of snapshots")
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-10-11 14:47:58 +02:00
David Sterba
295a53ccc4 btrfs: delete stale comments after merge conflict resolution
There are two comments in btrfs_cache_block_group that I left when
resolving conflict between commits ced8ecf026 "btrfs: fix space cache
corruption and potential double allocations" and 527c490f44 "btrfs:
delete btrfs_wait_space_cache_v1_finished".

The former reworked the caching logic to wait until the caching ends in
btrfs_cache_block_group while the latter only open coded the waiting.
Both removed btrfs_wait_space_cache_v1_finished, the correct code is
with the waiting and returning error. Thus the conflict resolution was
OK.

Signed-off-by: David Sterba <dsterba@suse.com>
2022-10-11 14:47:54 +02:00
Josef Bacik
9e769bd7e5 btrfs: unlock locked extent area if we have contention
In production we hit the following deadlock

task 1			task 2			task 3
------			------			------
fiemap(file)		falloc(file)		fsync(file)
						  write(0, 1MiB)
						  btrfs_commit_transaction()
						    wait_on(!pending_ordered)
			  lock(512MiB, 1GiB)
			  start_transaction
			    wait_on_transaction

  lock(0, 1GiB)
    wait_extent_bit(512MiB)

task 4
------
finish_ordered_extent(0, 1MiB)
  lock(0, 1MiB)
  **DEADLOCK**

This occurs because when task 1 does it's lock, it locks everything from
0-512MiB, and then waits for the 512MiB chunk to unlock.  task 2 will
never unlock because it's waiting on the transaction commit to happen,
the transaction commit is waiting for the outstanding ordered extents,
and then the ordered extent thread is blocked waiting on the 0-1MiB
range to unlock.

To fix this we have to clear anything we've locked so far, wait for the
extent_state that we contended on, and then try to re-lock the entire
range again.

CC: stable@vger.kernel.org # 5.15+
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-10-11 14:47:06 +02:00
David Sterba
c86eab81a2 btrfs: send: update command for protocol version check
For a protocol and command compatibility we have a helper that hasn't
been updated for v3 yet. We use it for verity so update where necessary.

Fixes: 38622010a6 ("btrfs: send: add support for fs-verity")
Signed-off-by: David Sterba <dsterba@suse.com>
2022-10-11 14:47:06 +02:00
Boris Burkov
9971a741c5 btrfs: send: allow protocol version 3 with CONFIG_BTRFS_DEBUG
We haven't finalized send stream v3 yet, so gate the send stream version
behind CONFIG_BTRFS_DEBUG as we want some way to test it.

The original verity send did not check the protocol version, so add that
actual protection as well.

Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Boris Burkov <boris@bur.io>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-10-11 14:46:55 +02:00