bcachefs: Fix race leading to btree node write getting stuck

Browse source

Checking btree_node_may_write() isn't atomic with the other btree flags,
dirty and need_write in particular. There was a rare race where we'd
unblock a node from writing while __btree_node_flush() was setting
need_write, and no thread would notice that the node was now both able
to write and needed to be written.

Fix this by adding btree node flags for will_make_reachable and
write_blocked that can be checked in the cmpxchg loop in
__bch2_btree_node_write.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

...

This commit is contained in:

Kent Overstreet 2022-02-27 09:56:33 -05:00 • committed by Kent Overstreet

parent 6f5f747c31

commit bf3efff5e4

5 changed files with 19 additions and 13 deletions

Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL

Download patch file Download diff file Expand all files Collapse all files

7

fs/bcachefs/btree_cache.c

View file

10

fs/bcachefs/btree_io.c

View file

6

fs/bcachefs/btree_io.h

View file

2

fs/bcachefs/btree_types.h

View file

7

fs/bcachefs/btree_update_interior.c

View file