From ab714aff4f744f52f0beae93ed441f2f5585eb7a Mon Sep 17 00:00:00 2001 From: Jan Kara Date: Thu, 30 Jun 2016 11:39:38 -0400 Subject: jbd2: move lockdep tracking to journal_s Currently lockdep map is tracked in each journal handle. To be able to expand lockdep support to cover also other cases where we depend on transaction commit and where handle is not available, move lockdep map into struct journal_s. Since this makes the lockdep map shared for all handles, we have to use rwsem_acquire_read() for acquisitions now. Signed-off-by: Jan Kara Signed-off-by: Theodore Ts'o --- include/linux/jbd2.h | 17 +++++++++++++---- 1 file changed, 13 insertions(+), 4 deletions(-) (limited to 'include') diff --git a/include/linux/jbd2.h b/include/linux/jbd2.h index efb232c5f668..3d210cbe4e1b 100644 --- a/include/linux/jbd2.h +++ b/include/linux/jbd2.h @@ -491,10 +491,6 @@ struct jbd2_journal_handle unsigned long h_start_jiffies; unsigned int h_requested_credits; - -#ifdef CONFIG_DEBUG_LOCK_ALLOC - struct lockdep_map h_lockdep_map; -#endif }; @@ -793,6 +789,7 @@ jbd2_time_diff(unsigned long start, unsigned long end) * @j_proc_entry: procfs entry for the jbd statistics directory * @j_stats: Overall statistics * @j_private: An opaque pointer to fs-private information. + * @j_trans_commit_map: Lockdep entity to track transaction commit dependencies */ struct journal_s @@ -1035,6 +1032,18 @@ struct journal_s /* Precomputed journal UUID checksum for seeding other checksums */ __u32 j_csum_seed; + +#ifdef CONFIG_DEBUG_LOCK_ALLOC + /* + * Lockdep entity to track transaction commit dependencies. Handles + * hold this "lock" for read, when we wait for commit, we acquire the + * "lock" for writing. This matches the properties of jbd2 journalling + * where the running transaction has to wait for all handles to be + * dropped to commit that transaction and also acquiring a handle may + * require transaction commit to finish. + */ + struct lockdep_map j_trans_commit_map; +#endif }; /* journal feature predicate functions */ -- cgit v1.2.3 From 1eaa566d368b214d99cbb973647c1b0b8102a9ae Mon Sep 17 00:00:00 2001 From: Jan Kara Date: Thu, 30 Jun 2016 11:40:54 -0400 Subject: jbd2: track more dependencies on transaction commit So far we were tracking only dependency on transaction commit due to starting a new handle (which may require commit to start a new transaction). Now add tracking also for other cases where we wait for transaction commit. This way lockdep can catch deadlocks e. g. because we call jbd2_journal_stop() for a synchronous handle with some locks held which rank below transaction start. Signed-off-by: Jan Kara Signed-off-by: Theodore Ts'o --- fs/jbd2/journal.c | 1 + fs/jbd2/transaction.c | 4 ++++ include/linux/jbd2.h | 6 ++++++ 3 files changed, 11 insertions(+) (limited to 'include') diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c index 208e4058040b..fc1d7a39b082 100644 --- a/fs/jbd2/journal.c +++ b/fs/jbd2/journal.c @@ -691,6 +691,7 @@ int jbd2_log_wait_commit(journal_t *journal, tid_t tid) { int err = 0; + jbd2_might_wait_for_commit(journal); read_lock(&journal->j_state_lock); #ifdef CONFIG_JBD2_DEBUG if (!tid_geq(journal->j_commit_request, tid)) { diff --git a/fs/jbd2/transaction.c b/fs/jbd2/transaction.c index c0065040c5be..b5bc3e249163 100644 --- a/fs/jbd2/transaction.c +++ b/fs/jbd2/transaction.c @@ -182,6 +182,8 @@ static int add_transaction_credits(journal_t *journal, int blocks, int needed; int total = blocks + rsv_blocks; + jbd2_might_wait_for_commit(journal); + /* * If the current transaction is locked down for commit, wait * for the lock to be released. @@ -695,6 +697,8 @@ void jbd2_journal_lock_updates(journal_t *journal) { DEFINE_WAIT(wait); + jbd2_might_wait_for_commit(journal); + write_lock(&journal->j_state_lock); ++journal->j_barrier_count; diff --git a/include/linux/jbd2.h b/include/linux/jbd2.h index 3d210cbe4e1b..dfaa1f4dcb0c 100644 --- a/include/linux/jbd2.h +++ b/include/linux/jbd2.h @@ -1046,6 +1046,12 @@ struct journal_s #endif }; +#define jbd2_might_wait_for_commit(j) \ + do { \ + rwsem_acquire(&j->j_trans_commit_map, 0, 0, _THIS_IP_); \ + rwsem_release(&j->j_trans_commit_map, 1, _THIS_IP_); \ + } while (0) + /* journal feature predicate functions */ #define JBD2_FEATURE_COMPAT_FUNCS(name, flagname) \ static inline bool jbd2_has_feature_##name(journal_t *j) \ -- cgit v1.2.3