md/bcache/journal.h

1 /* SPDX-License-Identifier: GPL-2.0 */
8  * The journal is treated as a circular buffer of buckets - a journal entry
16  * superblock - all the things that are frequently updated. This is for future
22  * Currently, we don't journal BTREE_REPLACE operations - this will hopefully be
23  * fixed eventually. This isn't a bug - BTREE_REPLACE is used for insertions
32  * journal entry still open - i.e. that has keys that haven't been flushed to
38  * zero, we pop it off - thus, the size of the fifo tells us the number of open
48  * might contain keys for many journal entries - we handle this by making sure
56  * last_seq - the oldest journal entry we still need. We write last_seq in each
61  * newest journal entry it contains - if we don't need that journal entry we
75  * allocate space for a journal write again - preferentially flushing btree
85 	atomic_t		*pin;  member
98 	struct closure_waitlist	wait;  member
110 	struct closure_waitlist	wait;  member
118 	DECLARE_FIFO(atomic_t, pin);
132 	 * journal writes it contains - so we know when a bucket can be reused.
148 	/* 1 - discard in flight, -1 - discard completed */
163 	(fifo_idx(&(c)->journal.pin, (l)) > fifo_idx(&(c)->journal.pin, (r)))
168 	(!(j)->blocks_free || fifo_free(&(j)->pin) <= 1)