Bug 202173

Summary:	Btrfs deadlock calling leaf_space_used() and btrfs_tree_read_lock()
Product:	File System	Reporter:	Eli V (eliventer)
Component:	btrfs	Assignee:	BTRFS virtual assignee (fs_btrfs)
Status:	RESOLVED CODE_FIX
Severity:	high	CC:	dsterba
Priority:	P1
Hardware:	All
OS:	Linux
Kernel Version:	4.19.12	Subsystem:
Regression:	No	Bisected commit-id:
Attachments:	dmesg stack traces just before deadlock

Description Eli V 2019-01-07 19:13:32 UTC

Running an rsync process writing to the btrfs filesystem deadlocked with a bunch of kworkers in leaf_space_used and one in btrfs_tree_read_lock(). The first stack trace in the attched file, hitting btrfs_lock_root_node(), was about 2 minutes before the deadlock when all activity on the filesystem stopped.

Comment 1 Eli V 2019-01-07 19:14:19 UTC

Created attachment 280299 [details]
dmesg stack traces just before deadlock

Comment 2 David Sterba 2019-01-08 16:17:24 UTC

Thanks for the report. Fix https://patchwork.kernel.org/patch/10751909/ will go to 5.0-rc and then to stable 4.19.x.