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Message-Id: <20200408215530.25649-6-harshads@google.com>
Date: Wed, 8 Apr 2020 14:55:16 -0700
From: Harshad Shirwadkar <harshadshirwadkar@...il.com>
To: linux-ext4@...r.kernel.org
Cc: tytso@....edu, Harshad Shirwadkar <harshadshirwadkar@...il.com>
Subject: [PATCH v6 06/20] jbd2: fast commit main commit path changes
From: Harshad Shirwadkar <harshadshirwadkar@...il.com>
Add 3 new APIs jbd2_start_async_fc_nowait(),
jbd2_start_async_fc_wait() and jbd2_stop_async_fc(). These APIs can be
used by file systems to indicate to jbd2 that they are starting or
stopping a fast commit.
Signed-off-by: Harshad Shirwadkar <harshadshirwadkar@...il.com>
---
fs/jbd2/commit.c | 21 +++++++++++
fs/jbd2/journal.c | 85 +++++++++++++++++++++++++++++++++++++++++++-
include/linux/jbd2.h | 21 +++++++++++
3 files changed, 126 insertions(+), 1 deletion(-)
diff --git a/fs/jbd2/commit.c b/fs/jbd2/commit.c
index e855d8260433..280d11591bcb 100644
--- a/fs/jbd2/commit.c
+++ b/fs/jbd2/commit.c
@@ -413,6 +413,23 @@ void jbd2_journal_commit_transaction(journal_t *journal)
J_ASSERT(journal->j_running_transaction != NULL);
J_ASSERT(journal->j_committing_transaction == NULL);
+ write_lock(&journal->j_state_lock);
+ journal->j_flags |= JBD2_FULL_COMMIT_ONGOING;
+ while (journal->j_flags & JBD2_FAST_COMMIT_ONGOING) {
+ DEFINE_WAIT(wait);
+
+ prepare_to_wait(&journal->j_wait_async_fc, &wait,
+ TASK_UNINTERRUPTIBLE);
+ write_unlock(&journal->j_state_lock);
+ schedule();
+ write_lock(&journal->j_state_lock);
+ finish_wait(&journal->j_wait_async_fc, &wait);
+ }
+ write_unlock(&journal->j_state_lock);
+
+ if (journal->j_fc_cleanup_callback)
+ journal->j_fc_cleanup_callback(journal);
+
commit_transaction = journal->j_running_transaction;
trace_jbd2_start_commit(journal, commit_transaction);
@@ -420,6 +437,7 @@ void jbd2_journal_commit_transaction(journal_t *journal)
commit_transaction->t_tid);
write_lock(&journal->j_state_lock);
+ journal->j_fc_off = 0;
J_ASSERT(commit_transaction->t_state == T_RUNNING);
commit_transaction->t_state = T_LOCKED;
@@ -1125,6 +1143,8 @@ void jbd2_journal_commit_transaction(journal_t *journal)
journal->j_commit_sequence, journal->j_tail_sequence);
write_lock(&journal->j_state_lock);
+ journal->j_flags &= ~JBD2_FULL_COMMIT_ONGOING;
+ journal->j_flags &= ~JBD2_FAST_COMMIT_ONGOING;
spin_lock(&journal->j_list_lock);
commit_transaction->t_state = T_FINISHED;
/* Check if the transaction can be dropped now that we are finished */
@@ -1136,6 +1156,7 @@ void jbd2_journal_commit_transaction(journal_t *journal)
spin_unlock(&journal->j_list_lock);
write_unlock(&journal->j_state_lock);
wake_up(&journal->j_wait_done_commit);
+ wake_up(&journal->j_wait_async_fc);
/*
* Calculate overall stats
diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
index f8f55d0814ea..d3897d155fb9 100644
--- a/fs/jbd2/journal.c
+++ b/fs/jbd2/journal.c
@@ -157,7 +157,9 @@ static void commit_timeout(struct timer_list *t)
*
* 1) COMMIT: Every so often we need to commit the current state of the
* filesystem to disk. The journal thread is responsible for writing
- * all of the metadata buffers to disk.
+ * all of the metadata buffers to disk. If a fast commit is ongoing
+ * journal thread waits until it's done and then copntinues from
+ * there on.
*
* 2) CHECKPOINT: We cannot reuse a used section of the log file until all
* of the data in that part of the log has been rewritten elsewhere on
@@ -714,6 +716,86 @@ int jbd2_log_wait_commit(journal_t *journal, tid_t tid)
return err;
}
+/*
+ * Returns 0 if async fc could be started. Returns -EINVAL if no full
+ * commit has been done yet. Returns -EALREADY if another fast /
+ * full commit is ongoing.
+ */
+int jbd2_start_async_fc_nowait(journal_t *journal, tid_t tid)
+{
+ /*
+ * Fast commits only allowed if at least one full commit has
+ * been processed.
+ */
+ if (!journal->j_stats.ts_tid)
+ return -EINVAL;
+
+ if (tid <= journal->j_commit_sequence)
+ return -EALREADY;
+
+ write_lock(&journal->j_state_lock);
+ if (journal->j_flags &
+ (JBD2_FAST_COMMIT_ONGOING | JBD2_FULL_COMMIT_ONGOING)) {
+ write_unlock(&journal->j_state_lock);
+ return -EALREADY;
+ }
+
+ journal->j_flags |= JBD2_FAST_COMMIT_ONGOING;
+ write_unlock(&journal->j_state_lock);
+
+ return 0;
+}
+
+/*
+ * Same as above but waits for any ongoing fast commits to complete.
+ * If a full commit is ongoing, this function returns with
+ * -EALREADY.
+ */
+int jbd2_start_async_fc_wait(journal_t *journal, tid_t tid)
+{
+ int ret;
+
+ /*
+ * Fast commits only allowed if at least one full commit has
+ * been processed.
+ */
+ if (!journal->j_stats.ts_tid)
+ return -EINVAL;
+
+ if (tid <= journal->j_commit_sequence)
+ return -EALREADY;
+
+ write_lock(&journal->j_state_lock);
+restart:
+ if (journal->j_flags & JBD2_FULL_COMMIT_ONGOING) {
+ ret = -EALREADY;
+ } else if (journal->j_flags & JBD2_FAST_COMMIT_ONGOING) {
+ DEFINE_WAIT(wait);
+
+ prepare_to_wait(&journal->j_wait_async_fc, &wait,
+ TASK_UNINTERRUPTIBLE);
+ write_unlock(&journal->j_state_lock);
+ schedule();
+ write_lock(&journal->j_state_lock);
+ finish_wait(&journal->j_wait_async_fc, &wait);
+ goto restart;
+ } else {
+ journal->j_flags |= JBD2_FAST_COMMIT_ONGOING;
+ ret = 0;
+ }
+ write_unlock(&journal->j_state_lock);
+
+ return ret;
+}
+
+void jbd2_stop_async_fc(journal_t *journal, tid_t tid)
+{
+ write_lock(&journal->j_state_lock);
+ journal->j_flags &= ~JBD2_FAST_COMMIT_ONGOING;
+ write_unlock(&journal->j_state_lock);
+ wake_up(&journal->j_wait_async_fc);
+}
+
/* Return 1 when transaction with given tid has already committed. */
int jbd2_transaction_committed(journal_t *journal, tid_t tid)
{
@@ -1140,6 +1222,7 @@ static journal_t *journal_init_common(struct block_device *bdev,
init_waitqueue_head(&journal->j_wait_commit);
init_waitqueue_head(&journal->j_wait_updates);
init_waitqueue_head(&journal->j_wait_reserved);
+ init_waitqueue_head(&journal->j_wait_async_fc);
mutex_init(&journal->j_barrier);
mutex_init(&journal->j_checkpoint_mutex);
spin_lock_init(&journal->j_revoke_lock);
diff --git a/include/linux/jbd2.h b/include/linux/jbd2.h
index 1fc981cca479..0a4d9d484528 100644
--- a/include/linux/jbd2.h
+++ b/include/linux/jbd2.h
@@ -853,6 +853,13 @@ struct journal_s
*/
wait_queue_head_t j_wait_reserved;
+ /**
+ * @j_wait_async_fc:
+ *
+ * Wait queue to wait for completion of async fast commits.
+ */
+ wait_queue_head_t j_wait_async_fc;
+
/**
* @j_checkpoint_mutex:
*
@@ -1203,6 +1210,14 @@ struct journal_s
*/
struct lockdep_map j_trans_commit_map;
#endif
+
+ /**
+ * @j_fc_cleanup_callback:
+ *
+ * Clean-up after fast commit or full commit. JBD2 calls this function
+ * after every commit operation.
+ */
+ void (*j_fc_cleanup_callback)(struct journal_s *journal);
};
#define jbd2_might_wait_for_commit(j) \
@@ -1288,6 +1303,8 @@ JBD2_FEATURE_INCOMPAT_FUNCS(fast_commit, FAST_COMMIT)
* data write error in ordered
* mode */
#define JBD2_REC_ERR 0x080 /* The errno in the sb has been recorded */
+#define JBD2_FAST_COMMIT_ONGOING 0x100 /* Fast commit is ongoing */
+#define JBD2_FULL_COMMIT_ONGOING 0x200 /* Full commit is ongoing */
/*
* Function declarations for the journaling transaction and buffer
@@ -1540,6 +1557,10 @@ void __jbd2_log_wait_for_space(journal_t *journal);
extern void __jbd2_journal_drop_transaction(journal_t *, transaction_t *);
extern int jbd2_cleanup_journal_tail(journal_t *);
+/* Fast commit related APIs */
+int jbd2_start_async_fc_nowait(journal_t *journal, tid_t tid);
+int jbd2_start_async_fc_wait(journal_t *journal, tid_t tid);
+void jbd2_stop_async_fc(journal_t *journal, tid_t tid);
void jbd2_init_fast_commit(journal_t *journal, int num_fc_blks);
/*
* is_journal_abort
--
2.26.0.110.g2183baf09c-goog
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