diff options
| -rw-r--r-- | fs/jbd2/commit.c | 32 | ||||
| -rw-r--r-- | fs/jbd2/journal.c | 13 | ||||
| -rw-r--r-- | include/linux/jbd2.h | 1 |
3 files changed, 46 insertions, 0 deletions
diff --git a/fs/jbd2/commit.c b/fs/jbd2/commit.c index b89ef84..1dfcb20 100644 --- a/fs/jbd2/commit.c +++ b/fs/jbd2/commit.c @@ -331,6 +331,10 @@ void jbd2_journal_commit_transaction(journal_t *journal) struct buffer_head *cbh = NULL; /* For transactional checksums */ __u32 crc32_sum = ~0; struct blk_plug plug; + /* Tail of the journal */ + unsigned long first_block; + tid_t first_tid; + int update_tail; /* * First job: lock down the current transaction and wait for @@ -688,10 +692,30 @@ start_journal_io: err = 0; } + /* + * Get current oldest transaction in the log before we issue flush + * to the filesystem device. After the flush we can be sure that + * blocks of all older transactions are checkpointed to persistent + * storage and we will be safe to update journal start in the + * superblock with the numbers we get here. + */ + update_tail = + jbd2_journal_get_log_tail(journal, &first_tid, &first_block); + write_lock(&journal->j_state_lock); + if (update_tail) { + long freed = first_block - journal->j_tail; + + if (first_block < journal->j_tail) + freed += journal->j_last - journal->j_first; + /* Update tail only if we free significant amount of space */ + if (freed < journal->j_maxlen / 4) + update_tail = 0; + } J_ASSERT(commit_transaction->t_state == T_COMMIT); commit_transaction->t_state = T_COMMIT_DFLUSH; write_unlock(&journal->j_state_lock); + /* * If the journal is not located on the file system device, * then we must flush the file system device before we issue @@ -842,6 +866,14 @@ wait_for_iobuf: if (err) jbd2_journal_abort(journal, err); + /* + * Now disk caches for filesystem device are flushed so we are safe to + * erase checkpointed transactions from the log by updating journal + * superblock. + */ + if (update_tail) + jbd2_update_log_tail(journal, first_tid, first_block); + /* End of a transaction! Finally, we can do checkpoint processing: any buffers committed as a result of this transaction can be removed from any checkpoint list it was on diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c index c5ff177..bda564f 100644 --- a/fs/jbd2/journal.c +++ b/fs/jbd2/journal.c @@ -821,6 +821,19 @@ void __jbd2_update_log_tail(journal_t *journal, tid_t tid, unsigned long block) write_unlock(&journal->j_state_lock); } +/* + * This is a variaon of __jbd2_update_log_tail which checks for validity of + * provided log tail and locks j_checkpoint_mutex. So it is safe against races + * with other threads updating log tail. + */ +void jbd2_update_log_tail(journal_t *journal, tid_t tid, unsigned long block) +{ + mutex_lock(&journal->j_checkpoint_mutex); + if (tid_gt(tid, journal->j_tail_sequence)) + __jbd2_update_log_tail(journal, tid, block); + mutex_unlock(&journal->j_checkpoint_mutex); +} + struct jbd2_stats_proc_session { journal_t *journal; struct transaction_stats_s *stats; diff --git a/include/linux/jbd2.h b/include/linux/jbd2.h index 876a7d8..912c30a 100644 --- a/include/linux/jbd2.h +++ b/include/linux/jbd2.h @@ -974,6 +974,7 @@ int jbd2_journal_next_log_block(journal_t *, unsigned long long *); int jbd2_journal_get_log_tail(journal_t *journal, tid_t *tid, unsigned long *block); void __jbd2_update_log_tail(journal_t *journal, tid_t tid, unsigned long block); +void jbd2_update_log_tail(journal_t *journal, tid_t tid, unsigned long block); /* Commit management */ extern void jbd2_journal_commit_transaction(journal_t *); |
