btrfs_destroy_inode WARN_ON.

[Dave Jones]

Just hit this on a tree from earlier this morning, v4.5-11140 or so.

WARNING: CPU: 2 PID: 32570 at fs/btrfs/inode.c:9261 btrfs_destroy_inode+0x389/0x3f0 [btrfs]
CPU: 2 PID: 32570 Comm: rm Not tainted 4.5.0-think+ #14
 ffffffffc039baf9 00000000ef721ef0 ffff88025966fc08 ffffffff8957bcdb
 0000000000000000 0000000000000000 ffff88025966fc50 ffffffff890b41f1
 ffff88045d918040 0000242d4eed6048 ffff88024eed6048 ffff88024eed6048
Call Trace:
 [<ffffffffc039baf9>] ? btrfs_destroy_inode+0x389/0x3f0 [btrfs]
 [<ffffffff8957bcdb>] dump_stack+0x68/0x9d
 [<ffffffff890b41f1>] __warn+0x111/0x130
 [<ffffffff890b43fd>] warn_slowpath_null+0x1d/0x20
 [<ffffffffc039baf9>] btrfs_destroy_inode+0x389/0x3f0 [btrfs]
 [<ffffffff89352307>] destroy_inode+0x67/0x90
 [<ffffffff893524e7>] evict+0x1b7/0x240
 [<ffffffff893529be>] iput+0x3ae/0x4e0
 [<ffffffff8934c93e>] ? dput+0x20e/0x460
 [<ffffffff8933ee26>] do_unlinkat+0x256/0x440
 [<ffffffff8933ebd0>] ? do_rmdir+0x350/0x350
 [<ffffffff890031e7>] ? syscall_trace_enter_phase1+0x87/0x260
 [<ffffffff89003160>] ? enter_from_user_mode+0x50/0x50
 [<ffffffff8913c3b5>] ? __lock_is_held+0x25/0xd0
 [<ffffffff891411f2>] ? mark_held_locks+0x22/0xc0
 [<ffffffff890034ed>] ? syscall_trace_enter_phase2+0x12d/0x3d0
 [<ffffffff893400b0>] ? SyS_rmdir+0x20/0x20
 [<ffffffff893400cb>] SyS_unlinkat+0x1b/0x30
 [<ffffffff89003ac4>] do_syscall_64+0xf4/0x240
 [<ffffffff89d520da>] entry_SYSCALL64_slow_path+0x25/0x25
---[ end trace a48ce4e6a1b5e409 ]---


That's WARN_ON(BTRFS_I(inode)->csum_bytes);

*maybe* it's a bad disk, but there's no indication in dmesg of anything awry.
Spinning rust on SATA, nothing special.

	Dave