1 files changed, 113 insertions, 69 deletions

diff --git a/fs/jbd/commit.c b/fs/jbd/commit.c
index 42da60784311..32a8caf0c41e 100644
--- a/fs/jbd/commit.c
+++ b/fs/jbd/commit.c
@@ -160,6 +160,117 @@ static int journal_write_commit_record(journal_t *journal,
         return (ret == -EIO);
 }
 
+static void journal_do_submit_data(struct buffer_head **wbuf, int bufs)
+{
+        int i;
+
+        for (i = 0; i < bufs; i++) {
+                wbuf[i]->b_end_io = end_buffer_write_sync;
+                /* We use-up our safety reference in submit_bh() */
+                submit_bh(WRITE, wbuf[i]);
+        }
+}
+
+/*
+ *  Submit all the data buffers to disk
+ */
+static void journal_submit_data_buffers(journal_t *journal,
+                                transaction_t *commit_transaction)
+{
+        struct journal_head *jh;
+        struct buffer_head *bh;
+        int locked;
+        int bufs = 0;
+        struct buffer_head **wbuf = journal->j_wbuf;
+
+        /*
+         * Whenever we unlock the journal and sleep, things can get added
+         * onto ->t_sync_datalist, so we have to keep looping back to
+         * write_out_data until we *know* that the list is empty.
+         *
+         * Cleanup any flushed data buffers from the data list.  Even in
+         * abort mode, we want to flush this out as soon as possible.
+         */
+write_out_data:
+        cond_resched();
+        spin_lock(&journal->j_list_lock);
+
+        while (commit_transaction->t_sync_datalist) {
+                jh = commit_transaction->t_sync_datalist;
+                bh = jh2bh(jh);
+                locked = 0;
+
+                /* Get reference just to make sure buffer does not disappear
+                 * when we are forced to drop various locks */
+                get_bh(bh);
+                /* If the buffer is dirty, we need to submit IO and hence
+                 * we need the buffer lock. We try to lock the buffer without
+                 * blocking. If we fail, we need to drop j_list_lock and do
+                 * blocking lock_buffer().
+                 */
+                if (buffer_dirty(bh)) {
+                        if (test_set_buffer_locked(bh)) {
+                                BUFFER_TRACE(bh, "needs blocking lock");
+                                spin_unlock(&journal->j_list_lock);
+                                /* Write out all data to prevent deadlocks */
+                                journal_do_submit_data(wbuf, bufs);
+                                bufs = 0;
+                                lock_buffer(bh);
+                                spin_lock(&journal->j_list_lock);
+                        }
+                        locked = 1;
+                }
+                /* We have to get bh_state lock. Again out of order, sigh. */
+                if (!inverted_lock(journal, bh)) {
+                        jbd_lock_bh_state(bh);
+                        spin_lock(&journal->j_list_lock);
+                }
+                /* Someone already cleaned up the buffer? */
+                if (!buffer_jbd(bh)
+                        || jh->b_transaction != commit_transaction
+                        || jh->b_jlist != BJ_SyncData) {
+                        jbd_unlock_bh_state(bh);
+                        if (locked)
+                                unlock_buffer(bh);
+                        BUFFER_TRACE(bh, "already cleaned up");
+                        put_bh(bh);
+                        continue;
+                }
+                if (locked && test_clear_buffer_dirty(bh)) {
+                        BUFFER_TRACE(bh, "needs writeout, adding to array");
+                        wbuf[bufs++] = bh;
+                        __journal_file_buffer(jh, commit_transaction,
+                                                BJ_Locked);
+                        jbd_unlock_bh_state(bh);
+                        if (bufs == journal->j_wbufsize) {
+                                spin_unlock(&journal->j_list_lock);
+                                journal_do_submit_data(wbuf, bufs);
+                                bufs = 0;
+                                goto write_out_data;
+                        }
+                }
+                else {
+                        BUFFER_TRACE(bh, "writeout complete: unfile");
+                        __journal_unfile_buffer(jh);
+                        jbd_unlock_bh_state(bh);
+                        if (locked)
+                                unlock_buffer(bh);
+                        journal_remove_journal_head(bh);
+                        /* Once for our safety reference, once for
+                         * journal_remove_journal_head() */
+                        put_bh(bh);
+                        put_bh(bh);
+                }
+
+                if (lock_need_resched(&journal->j_list_lock)) {
+                        spin_unlock(&journal->j_list_lock);
+                        goto write_out_data;
+                }
+        }
+        spin_unlock(&journal->j_list_lock);
+        journal_do_submit_data(wbuf, bufs);
+}
+
 /*
  * journal_commit_transaction
  *
@@ -313,80 +424,13 @@ void journal_commit_transaction(journal_t *journal)
          * Now start flushing things to disk, in the order they appear
          * on the transaction lists.  Data blocks go first.
          */
-
         err = 0;
-        /*
-         * Whenever we unlock the journal and sleep, things can get added
-         * onto ->t_sync_datalist, so we have to keep looping back to
-         * write_out_data until we *know* that the list is empty.
-         */
-        bufs = 0;
-        /*
-         * Cleanup any flushed data buffers from the data list.  Even in
-         * abort mode, we want to flush this out as soon as possible.
-         */
-write_out_data:
-        cond_resched();
-        spin_lock(&journal->j_list_lock);
-
-        while (commit_transaction->t_sync_datalist) {
-                struct buffer_head *bh;
-
-                jh = commit_transaction->t_sync_datalist;
-                commit_transaction->t_sync_datalist = jh->b_tnext;
-                bh = jh2bh(jh);
-                if (buffer_locked(bh)) {
-                        BUFFER_TRACE(bh, "locked");
-                        if (!inverted_lock(journal, bh))
-                                goto write_out_data;
-                        __journal_temp_unlink_buffer(jh);
-                        __journal_file_buffer(jh, commit_transaction,
-                                                BJ_Locked);
-                        jbd_unlock_bh_state(bh);
-                        if (lock_need_resched(&journal->j_list_lock)) {
-                                spin_unlock(&journal->j_list_lock);
-                                goto write_out_data;
-                        }
-                } else {
-                        if (buffer_dirty(bh)) {
-                                BUFFER_TRACE(bh, "start journal writeout");
-                                get_bh(bh);
-                                wbuf[bufs++] = bh;
-                                if (bufs == journal->j_wbufsize) {
-                                        jbd_debug(2, "submit %d writes\n",
-                                                        bufs);
-                                        spin_unlock(&journal->j_list_lock);
-                                        ll_rw_block(SWRITE, bufs, wbuf);
-                                        journal_brelse_array(wbuf, bufs);
-                                        bufs = 0;
-                                        goto write_out_data;
-                                }
-                        } else {
-                                BUFFER_TRACE(bh, "writeout complete: unfile");
-                                if (!inverted_lock(journal, bh))
-                                        goto write_out_data;
-                                __journal_unfile_buffer(jh);
-                                jbd_unlock_bh_state(bh);
-                                journal_remove_journal_head(bh);
-                                put_bh(bh);
-                                if (lock_need_resched(&journal->j_list_lock)) {
-                                        spin_unlock(&journal->j_list_lock);
-                                        goto write_out_data;
-                                }
-                        }
-                }
-        }
-
-        if (bufs) {
-                spin_unlock(&journal->j_list_lock);
-                ll_rw_block(SWRITE, bufs, wbuf);
-                journal_brelse_array(wbuf, bufs);
-                spin_lock(&journal->j_list_lock);
-        }
+        journal_submit_data_buffers(journal, commit_transaction);
 
         /*
          * Wait for all previously submitted IO to complete.
          */
+        spin_lock(&journal->j_list_lock);
         while (commit_transaction->t_locked_list) {
                 struct buffer_head *bh;