Merge branch 'for-2.6.26' of master.kernel.org:/pub/scm/linux/kernel/git/jwboyer...

[linux-2.6] / fs / jbd2 / transaction.c

diff --git a/fs/jbd2/transaction.c b/fs/jbd2/transaction.c
index b9b0b6f899b91b2000cc4f34e72c97931670fe53..d6e006e67804d5facfbad041797e87586266751b 100644 (file)
--- a/fs/jbd2/transaction.c
+++ b/fs/jbd2/transaction.c
@@ -617,6 +617,12 @@ repeat:
            jh->b_next_transaction == transaction)
                goto done;
 
+       /*
+        * this is the first time this transaction is touching this buffer,
+        * reset the modified flag
+        */
+       jh->b_modified = 0;
+
        /*
         * If there is already a copy-out version of this buffer, then we don't
         * need to make another one
@@ -690,7 +696,7 @@ repeat:
                                if (!frozen_buffer) {
                                        printk(KERN_EMERG
                                               "%s: OOM for frozen_buffer\n",
-                                              __FUNCTION__);
+                                              __func__);
                                        JBUFFER_TRACE(jh, "oom!");
                                        error = -ENOMEM;
                                        jbd_lock_bh_state(bh);
@@ -829,9 +835,16 @@ int jbd2_journal_get_create_access(handle_t *handle, struct buffer_head *bh)
 
        if (jh->b_transaction == NULL) {
                jh->b_transaction = transaction;
+
+               /* first access by this transaction */
+               jh->b_modified = 0;
+
                JBUFFER_TRACE(jh, "file as BJ_Reserved");
                __jbd2_journal_file_buffer(jh, transaction, BJ_Reserved);
        } else if (jh->b_transaction == journal->j_committing_transaction) {
+               /* first access by this transaction */
+               jh->b_modified = 0;
+
                JBUFFER_TRACE(jh, "set next transaction");
                jh->b_next_transaction = transaction;
        }
@@ -901,7 +914,7 @@ repeat:
                committed_data = jbd2_alloc(jh2bh(jh)->b_size, GFP_NOFS);
                if (!committed_data) {
                        printk(KERN_EMERG "%s: No memory for committed data\n",
-                               __FUNCTION__);
+                               __func__);
                        err = -ENOMEM;
                        goto out;
                }
@@ -1230,6 +1243,7 @@ int jbd2_journal_forget (handle_t *handle, struct buffer_head *bh)
        struct journal_head *jh;
        int drop_reserve = 0;
        int err = 0;
+       int was_modified = 0;
 
        BUFFER_TRACE(bh, "entry");
 
@@ -1248,6 +1262,9 @@ int jbd2_journal_forget (handle_t *handle, struct buffer_head *bh)
                goto not_jbd;
        }
 
+       /* keep track of wether or not this transaction modified us */
+       was_modified = jh->b_modified;
+
        /*
         * The buffer's going from the transaction, we must drop
         * all references -bzzz
@@ -1265,7 +1282,12 @@ int jbd2_journal_forget (handle_t *handle, struct buffer_head *bh)
 
                JBUFFER_TRACE(jh, "belongs to current transaction: unfile");
 
-               drop_reserve = 1;
+               /*
+                * we only want to drop a reference if this transaction
+                * modified the buffer
+                */
+               if (was_modified)
+                       drop_reserve = 1;
 
                /*
                 * We are no longer going to journal this buffer.
@@ -1305,7 +1327,13 @@ int jbd2_journal_forget (handle_t *handle, struct buffer_head *bh)
                if (jh->b_next_transaction) {
                        J_ASSERT(jh->b_next_transaction == transaction);
                        jh->b_next_transaction = NULL;
-                       drop_reserve = 1;
+
+                       /*
+                        * only drop a reference if this transaction modified
+                        * the buffer
+                        */
+                       if (was_modified)
+                               drop_reserve = 1;
                }
        }
 
@@ -1434,7 +1462,8 @@ int jbd2_journal_stop(handle_t *handle)
        return err;
 }
 
-/**int jbd2_journal_force_commit() - force any uncommitted transactions
+/**
+ * int jbd2_journal_force_commit() - force any uncommitted transactions
  * @journal: journal to force
  *
  * For synchronous operations: force any uncommitted transactions
@@ -2077,7 +2106,7 @@ void __jbd2_journal_refile_buffer(struct journal_head *jh)
        jh->b_transaction = jh->b_next_transaction;
        jh->b_next_transaction = NULL;
        __jbd2_journal_file_buffer(jh, jh->b_transaction,
-                               was_dirty ? BJ_Metadata : BJ_Reserved);
+                               jh->b_modified ? BJ_Metadata : BJ_Reserved);
        J_ASSERT_JH(jh, jh->b_transaction->t_state == T_RUNNING);
 
        if (was_dirty)