4 files changed, 51 insertions, 41 deletions

diff --git a/fs/jbd2/checkpoint.c b/fs/jbd2/checkpoint.c
index 076d1cc44f95..f8cdc02520f9 100644
--- a/fs/jbd2/checkpoint.c
+++ b/fs/jbd2/checkpoint.c
@@ -775,7 +775,7 @@ void __jbd2_journal_drop_transaction(journal_t *journal, transaction_t *transact
         J_ASSERT(transaction->t_log_list == NULL);
         J_ASSERT(transaction->t_checkpoint_list == NULL);
         J_ASSERT(transaction->t_checkpoint_io_list == NULL);
-        J_ASSERT(transaction->t_updates == 0);
+        J_ASSERT(atomic_read(&transaction->t_updates) == 0);
         J_ASSERT(journal->j_committing_transaction != transaction);
         J_ASSERT(journal->j_running_transaction != transaction);
 
diff --git a/fs/jbd2/commit.c b/fs/jbd2/commit.c
index af056810acb6..fbd2c564e916 100644
--- a/fs/jbd2/commit.c
+++ b/fs/jbd2/commit.c
@@ -417,12 +417,12 @@ void jbd2_journal_commit_transaction(journal_t *journal)
                                               stats.run.rs_locked);
 
         spin_lock(&commit_transaction->t_handle_lock);
-        while (commit_transaction->t_updates) {
+        while (atomic_read(&commit_transaction->t_updates)) {
                 DEFINE_WAIT(wait);
 
                 prepare_to_wait(&journal->j_wait_updates, &wait,
                                         TASK_UNINTERRUPTIBLE);
-                if (commit_transaction->t_updates) {
+                if (atomic_read(&commit_transaction->t_updates)) {
                         spin_unlock(&commit_transaction->t_handle_lock);
                         spin_unlock(&journal->j_state_lock);
                         schedule();
@@ -433,7 +433,7 @@ void jbd2_journal_commit_transaction(journal_t *journal)
         }
         spin_unlock(&commit_transaction->t_handle_lock);
 
-        J_ASSERT (commit_transaction->t_outstanding_credits <=
+        J_ASSERT (atomic_read(&commit_transaction->t_outstanding_credits) <=
                         journal->j_max_transaction_buffers);
 
         /*
@@ -527,11 +527,12 @@ void jbd2_journal_commit_transaction(journal_t *journal)
         stats.run.rs_logging = jiffies;
         stats.run.rs_flushing = jbd2_time_diff(stats.run.rs_flushing,
                                                stats.run.rs_logging);
-        stats.run.rs_blocks = commit_transaction->t_outstanding_credits;
+        stats.run.rs_blocks =
+                atomic_read(&commit_transaction->t_outstanding_credits);
         stats.run.rs_blocks_logged = 0;
 
         J_ASSERT(commit_transaction->t_nr_buffers <=
-                 commit_transaction->t_outstanding_credits);
+                 atomic_read(&commit_transaction->t_outstanding_credits));
 
         err = 0;
         descriptor = NULL;
@@ -616,7 +617,7 @@ void jbd2_journal_commit_transaction(journal_t *journal)
                  * the free space in the log, but this counter is changed
                  * by jbd2_journal_next_log_block() also.
                  */
-                commit_transaction->t_outstanding_credits--;
+                atomic_dec(&commit_transaction->t_outstanding_credits);
 
                 /* Bump b_count to prevent truncate from stumbling over
                    the shadowed buffer!  @@@ This can go if we ever get
diff --git a/fs/jbd2/transaction.c b/fs/jbd2/transaction.c
index 001e95fb0fe1..9c64c7ec48d4 100644
--- a/fs/jbd2/transaction.c
+++ b/fs/jbd2/transaction.c
@@ -55,6 +55,8 @@ jbd2_get_transaction(journal_t *journal, transaction_t *transaction)
         transaction->t_tid = journal->j_transaction_sequence++;
         transaction->t_expires = jiffies + journal->j_commit_interval;
         spin_lock_init(&transaction->t_handle_lock);
+        atomic_set(&transaction->t_updates, 0);
+        atomic_set(&transaction->t_outstanding_credits, 0);
         INIT_LIST_HEAD(&transaction->t_inode_list);
         INIT_LIST_HEAD(&transaction->t_private_list);
 
@@ -177,7 +179,7 @@ repeat_locked:
          * checkpoint to free some more log space.
          */
         spin_lock(&transaction->t_handle_lock);
-        needed = transaction->t_outstanding_credits + nblocks;
+        needed = atomic_read(&transaction->t_outstanding_credits) + nblocks;
 
         if (needed > journal->j_max_transaction_buffers) {
                 /*
@@ -240,11 +242,12 @@ repeat_locked:
         }
 
         handle->h_transaction = transaction;
-        transaction->t_outstanding_credits += nblocks;
-        transaction->t_updates++;
+        atomic_add(nblocks, &transaction->t_outstanding_credits);
+        atomic_inc(&transaction->t_updates);
         transaction->t_handle_count++;
         jbd_debug(4, "Handle %p given %d credits (total %d, free %d)\n",
-                  handle, nblocks, transaction->t_outstanding_credits,
+                  handle, nblocks,
+                  atomic_read(&transaction->t_outstanding_credits),
                   __jbd2_log_space_left(journal));
         spin_unlock(&transaction->t_handle_lock);
         spin_unlock(&journal->j_state_lock);
@@ -369,7 +372,7 @@ int jbd2_journal_extend(handle_t *handle, int nblocks)
         }
 
         spin_lock(&transaction->t_handle_lock);
-        wanted = transaction->t_outstanding_credits + nblocks;
+        wanted = atomic_read(&transaction->t_outstanding_credits) + nblocks;
 
         if (wanted > journal->j_max_transaction_buffers) {
                 jbd_debug(3, "denied handle %p %d blocks: "
@@ -384,7 +387,7 @@ int jbd2_journal_extend(handle_t *handle, int nblocks)
         }
 
         handle->h_buffer_credits += nblocks;
-        transaction->t_outstanding_credits += nblocks;
+        atomic_add(nblocks, &transaction->t_outstanding_credits);
         result = 0;
 
         jbd_debug(3, "extended handle %p by %d\n", handle, nblocks);
@@ -426,15 +429,14 @@ int jbd2__journal_restart(handle_t *handle, int nblocks, int gfp_mask)
          * First unlink the handle from its current transaction, and start the
          * commit on that.
          */
-        J_ASSERT(transaction->t_updates > 0);
+        J_ASSERT(atomic_read(&transaction->t_updates) > 0);
         J_ASSERT(journal_current_handle() == handle);
 
         spin_lock(&journal->j_state_lock);
         spin_lock(&transaction->t_handle_lock);
-        transaction->t_outstanding_credits -= handle->h_buffer_credits;
-        transaction->t_updates--;
-
-        if (!transaction->t_updates)
+        atomic_sub(handle->h_buffer_credits,
+                   &transaction->t_outstanding_credits);
+        if (atomic_dec_and_test(&transaction->t_updates))
                 wake_up(&journal->j_wait_updates);
         spin_unlock(&transaction->t_handle_lock);
 
@@ -481,7 +483,7 @@ void jbd2_journal_lock_updates(journal_t *journal)
                         break;
 
                 spin_lock(&transaction->t_handle_lock);
-                if (!transaction->t_updates) {
+                if (!atomic_read(&transaction->t_updates)) {
                         spin_unlock(&transaction->t_handle_lock);
                         break;
                 }
@@ -1258,7 +1260,8 @@ int jbd2_journal_stop(handle_t *handle)
 {
         transaction_t *transaction = handle->h_transaction;
         journal_t *journal = transaction->t_journal;
-        int err;
+        int err, wait_for_commit = 0;
+        tid_t tid;
         pid_t pid;
 
         J_ASSERT(journal_current_handle() == handle);
@@ -1266,7 +1269,7 @@ int jbd2_journal_stop(handle_t *handle)
         if (is_handle_aborted(handle))
                 err = -EIO;
         else {
-                J_ASSERT(transaction->t_updates > 0);
+                J_ASSERT(atomic_read(&transaction->t_updates) > 0);
                 err = 0;
         }
 
@@ -1334,14 +1337,8 @@ int jbd2_journal_stop(handle_t *handle)
         if (handle->h_sync)
                 transaction->t_synchronous_commit = 1;
         current->journal_info = NULL;
-        spin_lock(&transaction->t_handle_lock);
-        transaction->t_outstanding_credits -= handle->h_buffer_credits;
-        transaction->t_updates--;
-        if (!transaction->t_updates) {
-                wake_up(&journal->j_wait_updates);
-                if (journal->j_barrier_count)
-                        wake_up(&journal->j_wait_transaction_locked);
-        }
+        atomic_sub(handle->h_buffer_credits,
+                   &transaction->t_outstanding_credits);
 
         /*
          * If the handle is marked SYNC, we need to set another commit
@@ -1350,15 +1347,13 @@ int jbd2_journal_stop(handle_t *handle)
          * transaction is too old now.
          */
         if (handle->h_sync ||
-                        transaction->t_outstanding_credits >
-                                journal->j_max_transaction_buffers ||
-                        time_after_eq(jiffies, transaction->t_expires)) {
+            (atomic_read(&transaction->t_outstanding_credits) >
+             journal->j_max_transaction_buffers) ||
+            time_after_eq(jiffies, transaction->t_expires)) {
                 /* Do this even for aborted journals: an abort still
                  * completes the commit thread, it just doesn't write
                  * anything to disk. */
-                tid_t tid = transaction->t_tid;
 
-                spin_unlock(&transaction->t_handle_lock);
                 jbd_debug(2, "transaction too old, requesting commit for "
                                         "handle %p\n", handle);
                 /* This is non-blocking */
@@ -1369,11 +1364,25 @@ int jbd2_journal_stop(handle_t *handle)
                  * to wait for the commit to complete.
                  */
                 if (handle->h_sync && !(current->flags & PF_MEMALLOC))
-                        err = jbd2_log_wait_commit(journal, tid);
-        } else {
-                spin_unlock(&transaction->t_handle_lock);
+                        wait_for_commit = 1;
         }
 
+        /*
+         * Once we drop t_updates, if it goes to zero the transaction
+         * could start commiting on us and eventually disappear.  So
+         * once we do this, we must not dereference transaction
+         * pointer again.
+         */
+        tid = transaction->t_tid;
+        if (atomic_dec_and_test(&transaction->t_updates)) {
+                wake_up(&journal->j_wait_updates);
+                if (journal->j_barrier_count)
+                        wake_up(&journal->j_wait_transaction_locked);
+        }
+
+        if (wait_for_commit)
+                err = jbd2_log_wait_commit(journal, tid);
+
         lock_map_release(&handle->h_lockdep_map);
 
         jbd2_free_handle(handle);
diff --git a/include/linux/jbd2.h b/include/linux/jbd2.h
index 5a72bc75b273..a72ce21de0e1 100644
--- a/include/linux/jbd2.h
+++ b/include/linux/jbd2.h
@@ -601,13 +601,13 @@ struct transaction_s
          * Number of outstanding updates running on this transaction
          * [t_handle_lock]
          */
-        int                     t_updates;
+        atomic_t                t_updates;
 
         /*
          * Number of buffers reserved for use by all handles in this transaction
          * handle but not yet modified. [t_handle_lock]
          */
-        int                     t_outstanding_credits;
+        atomic_t                t_outstanding_credits;
 
         /*
          * Forward and backward links for the circular list of all transactions
@@ -1258,8 +1258,8 @@ static inline int jbd_space_needed(journal_t *journal)
 {
         int nblocks = journal->j_max_transaction_buffers;
         if (journal->j_committing_transaction)
-                nblocks += journal->j_committing_transaction->
-                                        t_outstanding_credits;
+                nblocks += atomic_read(&journal->j_committing_transaction->
+                                       t_outstanding_credits);
         return nblocks;
 }