Merge branch 'sh-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git...

[pandora-kernel.git] / fs / jbd2 / journal.c

diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
index 9a78269..0dfa5b5 100644 (file)
--- a/fs/jbd2/journal.c
+++ b/fs/jbd2/journal.c
@@ -2078,10 +2078,9 @@ static void journal_free_journal_head(struct journal_head *jh)
  * When a buffer has its BH_JBD bit set it is immune from being released by
  * core kernel code, mainly via ->b_count.
  *
- * A journal_head may be detached from its buffer_head when the journal_head's
- * b_transaction, b_cp_transaction and b_next_transaction pointers are NULL.
- * Various places in JBD call jbd2_journal_remove_journal_head() to indicate that the
- * journal_head can be dropped if needed.
+ * A journal_head is detached from its buffer_head when the journal_head's
+ * b_jcount reaches zero. Running transaction (b_transaction) and checkpoint
+ * transaction (b_cp_transaction) hold their references to b_jcount.
  *
  * Various places in the kernel want to attach a journal_head to a buffer_head
  * _before_ attaching the journal_head to a transaction.  To protect the
@@ -2094,17 +2093,16 @@ static void journal_free_journal_head(struct journal_head *jh)
  *     (Attach a journal_head if needed.  Increments b_jcount)
  *     struct journal_head *jh = jbd2_journal_add_journal_head(bh);
  *     ...
+ *      (Get another reference for transaction)
+ *     jbd2_journal_grab_journal_head(bh);
  *     jh->b_transaction = xxx;
+ *     (Put original reference)
  *     jbd2_journal_put_journal_head(jh);
- *
- * Now, the journal_head's b_jcount is zero, but it is safe from being released
- * because it has a non-zero b_transaction.
  */
 
 /*
  * Give a buffer_head a journal_head.
  *
- * Doesn't need the journal lock.
  * May sleep.
  */
 struct journal_head *jbd2_journal_add_journal_head(struct buffer_head *bh)
@@ -2168,61 +2166,29 @@ static void __journal_remove_journal_head(struct buffer_head *bh)
        struct journal_head *jh = bh2jh(bh);
 
        J_ASSERT_JH(jh, jh->b_jcount >= 0);
-
-       get_bh(bh);
-       if (jh->b_jcount == 0) {
-               if (jh->b_transaction == NULL &&
-                               jh->b_next_transaction == NULL &&
-                               jh->b_cp_transaction == NULL) {
-                       J_ASSERT_JH(jh, jh->b_jlist == BJ_None);
-                       J_ASSERT_BH(bh, buffer_jbd(bh));
-                       J_ASSERT_BH(bh, jh2bh(jh) == bh);
-                       BUFFER_TRACE(bh, "remove journal_head");
-                       if (jh->b_frozen_data) {
-                               printk(KERN_WARNING "%s: freeing "
-                                               "b_frozen_data\n",
-                                               __func__);
-                               jbd2_free(jh->b_frozen_data, bh->b_size);
-                       }
-                       if (jh->b_committed_data) {
-                               printk(KERN_WARNING "%s: freeing "
-                                               "b_committed_data\n",
-                                               __func__);
-                               jbd2_free(jh->b_committed_data, bh->b_size);
-                       }
-                       bh->b_private = NULL;
-                       jh->b_bh = NULL;        /* debug, really */
-                       clear_buffer_jbd(bh);
-                       __brelse(bh);
-                       journal_free_journal_head(jh);
-               } else {
-                       BUFFER_TRACE(bh, "journal_head was locked");
-               }
+       J_ASSERT_JH(jh, jh->b_transaction == NULL);
+       J_ASSERT_JH(jh, jh->b_next_transaction == NULL);
+       J_ASSERT_JH(jh, jh->b_cp_transaction == NULL);
+       J_ASSERT_JH(jh, jh->b_jlist == BJ_None);
+       J_ASSERT_BH(bh, buffer_jbd(bh));
+       J_ASSERT_BH(bh, jh2bh(jh) == bh);
+       BUFFER_TRACE(bh, "remove journal_head");
+       if (jh->b_frozen_data) {
+               printk(KERN_WARNING "%s: freeing b_frozen_data\n", __func__);
+               jbd2_free(jh->b_frozen_data, bh->b_size);
        }
+       if (jh->b_committed_data) {
+               printk(KERN_WARNING "%s: freeing b_committed_data\n", __func__);
+               jbd2_free(jh->b_committed_data, bh->b_size);
+       }
+       bh->b_private = NULL;
+       jh->b_bh = NULL;        /* debug, really */
+       clear_buffer_jbd(bh);
+       journal_free_journal_head(jh);
 }
 
 /*
- * jbd2_journal_remove_journal_head(): if the buffer isn't attached to a transaction
- * and has a zero b_jcount then remove and release its journal_head.   If we did
- * see that the buffer is not used by any transaction we also "logically"
- * decrement ->b_count.
- *
- * We in fact take an additional increment on ->b_count as a convenience,
- * because the caller usually wants to do additional things with the bh
- * after calling here.
- * The caller of jbd2_journal_remove_journal_head() *must* run __brelse(bh) at some
- * time.  Once the caller has run __brelse(), the buffer is eligible for
- * reaping by try_to_free_buffers().
- */
-void jbd2_journal_remove_journal_head(struct buffer_head *bh)
-{
-       jbd_lock_bh_journal_head(bh);
-       __journal_remove_journal_head(bh);
-       jbd_unlock_bh_journal_head(bh);
-}
-
-/*
- * Drop a reference on the passed journal_head.  If it fell to zero then try to
+ * Drop a reference on the passed journal_head.  If it fell to zero then
  * release the journal_head from the buffer_head.
  */
 void jbd2_journal_put_journal_head(struct journal_head *jh)
@@ -2232,11 +2198,12 @@ void jbd2_journal_put_journal_head(struct journal_head *jh)
        jbd_lock_bh_journal_head(bh);
        J_ASSERT_JH(jh, jh->b_jcount > 0);
        --jh->b_jcount;
-       if (!jh->b_jcount && !jh->b_transaction) {
+       if (!jh->b_jcount) {
                __journal_remove_journal_head(bh);
+               jbd_unlock_bh_journal_head(bh);
                __brelse(bh);
-       }
-       jbd_unlock_bh_journal_head(bh);
+       } else
+               jbd_unlock_bh_journal_head(bh);
 }
 
 /*