Btrfs: fix deadlock on metadata reservation when evicting a inode

When I ran the xfstests, I found the test tasks was blocked on meta-data

By debugging, I found the reason of this bug:
   start transaction
   reserve meta-data space
   flush delay allocation -> iput inode -> evict inode
	^					|
	|					v
   wait for delay allocation flush <- reserve meta-data space

And besides that, the flush on evicting inode will block the thread, which
is reclaiming the memory, and make oom happen easily.

Fix this bug by skipping the flush step when evicting inode.

Signed-off-by: Miao Xie <>
3 files changed