While trying to track down a lost EIO problem I hit the following
assertion while doing my error injection testing

  BTRFS warning (device nvme1n1): transaction 1609 (with 180224 dirty metadata bytes) is not committed
  assertion failed: !found, in fs/btrfs/disk-io.c:4456
  ------------[ cut here ]------------
  kernel BUG at fs/btrfs/messages.h:169!
  invalid opcode: 0000 [#1] PREEMPT SMP NOPTI
  CPU: 0 PID: 1445 Comm: mount Tainted: G        W          6.2.0-rc5+ #3
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.1-2.fc37 04/01/2014
  RIP: 0010:btrfs_assertfail.constprop.0+0x18/0x1a
  RSP: 0018:ffffb95fc3b0bc68 EFLAGS: 00010286
  RAX: 0000000000000034 RBX: ffff9941c2ac2000 RCX: 0000000000000000
  RDX: 0000000000000001 RSI: ffffffffb6741f7d RDI: 00000000ffffffff
  RBP: ffff9941c2ac2428 R08: 0000000000000000 R09: ffffb95fc3b0bb38
  R10: 0000000000000003 R11: ffffffffb71438a8 R12: ffff9941c2ac2428
  R13: ffff9941c2ac2450 R14: ffff9941c2ac2450 R15: 000000000002c000
  FS:  00007fcea2d07800(0000) GS:ffff9941fbc00000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: 00007f00cc7c83a8 CR3: 000000010c686000 CR4: 0000000000350ef0
  Call Trace:
   <TASK>
   close_ctree+0x426/0x48f
   btrfs_mount_root.cold+0x7e/0xee
   ? legacy_parse_param+0x2b/0x220
   legacy_get_tree+0x2b/0x50
   vfs_get_tree+0x29/0xc0
   vfs_kern_mount.part.0+0x73/0xb0
   btrfs_mount+0x11d/0x3d0
   ? legacy_parse_param+0x2b/0x220
   legacy_get_tree+0x2b/0x50
   vfs_get_tree+0x29/0xc0
   path_mount+0x438/0xa40
   __x64_sys_mount+0xe9/0x130
   do_syscall_64+0x3e/0x90
   entry_SYSCALL_64_after_hwframe+0x72/0xdc

This is because the error injection did an EIO for the root inode lookup
and we simply jumped to closing the ctree.  However because we didn't
mark the file system as having an error we skipped all of the broken
transaction cleanup stuff, and thus triggered this ASSERT().  Fix this
by calling btrfs_handle_fs_error() in this case so we have the error set
on the file system.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>