jbd: clean up journal_try_to_free_buffers()
[safe/jmp/linux-2.6] / fs / jbd / transaction.c
index db84045..73242ba 100644 (file)
@@ -25,6 +25,7 @@
 #include <linux/timer.h>
 #include <linux/mm.h>
 #include <linux/highmem.h>
+#include <linux/hrtimer.h>
 
 static void __journal_temp_unlink_buffer(struct journal_head *jh);
 
@@ -49,6 +50,7 @@ get_transaction(journal_t *journal, transaction_t *transaction)
 {
        transaction->t_journal = journal;
        transaction->t_state = T_RUNNING;
+       transaction->t_start_time = ktime_get();
        transaction->t_tid = journal->j_transaction_sequence++;
        transaction->t_expires = jiffies + journal->j_commit_interval;
        spin_lock_init(&transaction->t_handle_lock);
@@ -96,13 +98,12 @@ static int start_this_handle(journal_t *journal, handle_t *handle)
 
 alloc_transaction:
        if (!journal->j_running_transaction) {
-               new_transaction = jbd_kmalloc(sizeof(*new_transaction),
-                                               GFP_NOFS);
+               new_transaction = kzalloc(sizeof(*new_transaction),
+                                               GFP_NOFS|__GFP_NOFAIL);
                if (!new_transaction) {
                        ret = -ENOMEM;
                        goto out;
                }
-               memset(new_transaction, 0, sizeof(*new_transaction));
        }
 
        jbd_debug(3, "New handle %p going live.\n", handle);
@@ -289,10 +290,12 @@ handle_t *journal_start(journal_t *journal, int nblocks)
                jbd_free_handle(handle);
                current->journal_info = NULL;
                handle = ERR_PTR(err);
+               goto out;
        }
 
-       lock_acquire(&handle->h_lockdep_map, 0, 0, 0, 2, _THIS_IP_);
+       lock_map_acquire(&handle->h_lockdep_map);
 
+out:
        return handle;
 }
 
@@ -368,7 +371,7 @@ out:
 
 
 /**
- * int journal_restart() - restart a handle .
+ * int journal_restart() - restart a handle.
  * @handle:  handle to restart
  * @nblocks: nr credits requested
  *
@@ -608,6 +611,12 @@ repeat:
                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
         */
@@ -680,7 +689,7 @@ 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);
@@ -745,7 +754,6 @@ out:
  * int journal_get_write_access() - notify intent to modify a buffer for metadata (not data) update.
  * @handle: transaction to add buffer modifications to
  * @bh:     bh to be used for metadata writes
- * @credits: variable that will receive credits for the buffer
  *
  * Returns an error code or 0 on success.
  *
@@ -819,9 +827,16 @@ int 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");
                __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;
        }
@@ -843,11 +858,9 @@ out:
 }
 
 /**
- * int journal_get_undo_access() -  Notify intent to modify metadata with
- *     non-rewindable consequences
+ * int journal_get_undo_access() - Notify intent to modify metadata with non-rewindable consequences
  * @handle: transaction
  * @bh: buffer to undo
- * @credits: store the number of taken credits here (if not NULL)
  *
  * Sometimes there is a need to distinguish between metadata which has
  * been committed to disk and that which has not.  The ext3fs code uses
@@ -891,7 +904,7 @@ repeat:
                committed_data = jbd_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;
                }
@@ -920,12 +933,14 @@ out:
 }
 
 /**
- * int journal_dirty_data() -  mark a buffer as containing dirty data which
- *                             needs to be flushed before we can commit the
- *                             current transaction.
+ * int journal_dirty_data() - mark a buffer as containing dirty data to be flushed
  * @handle: transaction
  * @bh: bufferhead to mark
  *
+ * Description:
+ * Mark a buffer as containing dirty data which needs to be flushed before
+ * we can commit the current transaction.
+ *
  * The buffer is placed on the transaction's data list and is marked as
  * belonging to the transaction.
  *
@@ -939,9 +954,10 @@ int journal_dirty_data(handle_t *handle, struct buffer_head *bh)
        journal_t *journal = handle->h_transaction->t_journal;
        int need_brelse = 0;
        struct journal_head *jh;
+       int ret = 0;
 
        if (is_handle_aborted(handle))
-               return 0;
+               return ret;
 
        jh = journal_add_journal_head(bh);
        JBUFFER_TRACE(jh, "entry");
@@ -1052,7 +1068,16 @@ int journal_dirty_data(handle_t *handle, struct buffer_head *bh)
                                   time if it is redirtied */
                        }
 
-                       /* journal_clean_data_list() may have got there first */
+                       /*
+                        * We cannot remove the buffer with io error from the
+                        * committing transaction, because otherwise it would
+                        * miss the error and the commit would not abort.
+                        */
+                       if (unlikely(!buffer_uptodate(bh))) {
+                               ret = -EIO;
+                               goto no_journal;
+                       }
+
                        if (jh->b_transaction != NULL) {
                                JBUFFER_TRACE(jh, "unfile from commit");
                                __journal_temp_unlink_buffer(jh);
@@ -1093,15 +1118,15 @@ no_journal:
        }
        JBUFFER_TRACE(jh, "exit");
        journal_put_journal_head(jh);
-       return 0;
+       return ret;
 }
 
 /**
- * int journal_dirty_metadata() -  mark a buffer as containing dirty metadata
+ * int journal_dirty_metadata() - mark a buffer as containing dirty metadata
  * @handle: transaction to add buffer to.
  * @bh: buffer to mark
  *
- * mark dirty metadata which needs to be journaled as part of the current
+ * Mark dirty metadata which needs to be journaled as part of the current
  * transaction.
  *
  * The buffer is placed on the transaction's metadata list and is marked
@@ -1172,7 +1197,7 @@ int journal_dirty_metadata(handle_t *handle, struct buffer_head *bh)
        }
 
        /* That test should have eliminated the following case: */
-       J_ASSERT_JH(jh, jh->b_frozen_data == 0);
+       J_ASSERT_JH(jh, jh->b_frozen_data == NULL);
 
        JBUFFER_TRACE(jh, "file as BJ_Metadata");
        spin_lock(&journal->j_list_lock);
@@ -1220,6 +1245,7 @@ int 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");
 
@@ -1238,6 +1264,9 @@ int 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
@@ -1255,7 +1284,12 @@ int 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.
@@ -1295,7 +1329,13 @@ int 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;
                }
        }
 
@@ -1331,7 +1371,7 @@ int journal_stop(handle_t *handle)
 {
        transaction_t *transaction = handle->h_transaction;
        journal_t *journal = transaction->t_journal;
-       int old_handle_count, err;
+       int err;
        pid_t pid;
 
        J_ASSERT(journal_current_handle() == handle);
@@ -1360,6 +1400,17 @@ int journal_stop(handle_t *handle)
         * on IO anyway.  Speeds up many-threaded, many-dir operations
         * by 30x or more...
         *
+        * We try and optimize the sleep time against what the underlying disk
+        * can do, instead of having a static sleep time.  This is usefull for
+        * the case where our storage is so fast that it is more optimal to go
+        * ahead and force a flush and wait for the transaction to be committed
+        * than it is to wait for an arbitrary amount of time for new writers to
+        * join the transaction.  We acheive this by measuring how long it takes
+        * to commit a transaction, and compare it with how long this
+        * transaction has been running, and if run time < commit time then we
+        * sleep for the delta and commit.  This greatly helps super fast disks
+        * that would see slowdowns as more threads started doing fsyncs.
+        *
         * But don't do this if this process was the most recent one to
         * perform a synchronous write.  We do this to detect the case where a
         * single process is doing a stream of sync writes.  No point in waiting
@@ -1367,13 +1418,30 @@ int journal_stop(handle_t *handle)
         */
        pid = current->pid;
        if (handle->h_sync && journal->j_last_sync_writer != pid) {
+               u64 commit_time, trans_time;
+
                journal->j_last_sync_writer = pid;
-               do {
-                       old_handle_count = transaction->t_handle_count;
-                       schedule_timeout_uninterruptible(1);
-               } while (old_handle_count != transaction->t_handle_count);
+
+               spin_lock(&journal->j_state_lock);
+               commit_time = journal->j_average_commit_time;
+               spin_unlock(&journal->j_state_lock);
+
+               trans_time = ktime_to_ns(ktime_sub(ktime_get(),
+                                                  transaction->t_start_time));
+
+               commit_time = min_t(u64, commit_time,
+                                   1000*jiffies_to_usecs(1));
+
+               if (trans_time < commit_time) {
+                       ktime_t expires = ktime_add_ns(ktime_get(),
+                                                      commit_time);
+                       set_current_state(TASK_UNINTERRUPTIBLE);
+                       schedule_hrtimeout(&expires, HRTIMER_MODE_ABS);
+               }
        }
 
+       if (handle->h_sync)
+               transaction->t_synchronous_commit = 1;
        current->journal_info = NULL;
        spin_lock(&journal->j_state_lock);
        spin_lock(&transaction->t_handle_lock);
@@ -1418,13 +1486,14 @@ int journal_stop(handle_t *handle)
                spin_unlock(&journal->j_state_lock);
        }
 
-       lock_release(&handle->h_lockdep_map, 1, _THIS_IP_);
+       lock_map_release(&handle->h_lockdep_map);
 
        jbd_free_handle(handle);
        return err;
 }
 
-/**int journal_force_commit() - force any uncommitted transactions
+/**
+ * int journal_force_commit() - force any uncommitted transactions
  * @journal: journal to force
  *
  * For synchronous operations: force any uncommitted transactions
@@ -1522,7 +1591,7 @@ static void __journal_temp_unlink_buffer(struct journal_head *jh)
 
        J_ASSERT_JH(jh, jh->b_jlist < BJ_Types);
        if (jh->b_jlist != BJ_None)
-               J_ASSERT_JH(jh, transaction != 0);
+               J_ASSERT_JH(jh, transaction != NULL);
 
        switch (jh->b_jlist) {
        case BJ_None:
@@ -1591,11 +1660,11 @@ __journal_try_to_free_buffer(journal_t *journal, struct buffer_head *bh)
        if (buffer_locked(bh) || buffer_dirty(bh))
                goto out;
 
-       if (jh->b_next_transaction != 0)
+       if (jh->b_next_transaction != NULL)
                goto out;
 
        spin_lock(&journal->j_list_lock);
-       if (jh->b_transaction != 0 && jh->b_cp_transaction == 0) {
+       if (jh->b_transaction != NULL && jh->b_cp_transaction == NULL) {
                if (jh->b_jlist == BJ_SyncData || jh->b_jlist == BJ_Locked) {
                        /* A written-back ordered data buffer */
                        JBUFFER_TRACE(jh, "release data");
@@ -1603,7 +1672,7 @@ __journal_try_to_free_buffer(journal_t *journal, struct buffer_head *bh)
                        journal_remove_journal_head(bh);
                        __brelse(bh);
                }
-       } else if (jh->b_cp_transaction != 0 && jh->b_transaction == 0) {
+       } else if (jh->b_cp_transaction != NULL && jh->b_transaction == NULL) {
                /* written-back checkpointed metadata buffer */
                if (jh->b_jlist == BJ_None) {
                        JBUFFER_TRACE(jh, "remove from checkpoint list");
@@ -1617,12 +1686,13 @@ out:
        return;
 }
 
-
 /**
  * int journal_try_to_free_buffers() - try to free page buffers.
  * @journal: journal for operation
  * @page: to try and free
- * @unused_gfp_mask: unused
+ * @gfp_mask: we use the mask to detect how hard should we try to release
+ * buffers. If __GFP_WAIT and __GFP_FS is set, we wait for commit code to
+ * release the buffers.
  *
  *
  * For all the buffers on this page,
@@ -1651,9 +1721,11 @@ out:
  * journal_try_to_free_buffer() is changing its state.  But that
  * cannot happen because we never reallocate freed data as metadata
  * while the data is part of a transaction.  Yes?
+ *
+ * Return 0 on failure, 1 on success
  */
 int journal_try_to_free_buffers(journal_t *journal,
-                               struct page *page, gfp_t unused_gfp_mask)
+                               struct page *page, gfp_t gfp_mask)
 {
        struct buffer_head *head;
        struct buffer_head *bh;
@@ -1682,7 +1754,9 @@ int journal_try_to_free_buffers(journal_t *journal,
                if (buffer_jbd(bh))
                        goto busy;
        } while ((bh = bh->b_this_page) != head);
+
        ret = try_to_free_buffers(page);
+
 busy:
        return ret;
 }
@@ -1901,13 +1975,12 @@ zap_buffer_unlocked:
 }
 
 /**
- * void journal_invalidatepage()
- * @journal: journal to use for flush...
+ * void journal_invalidatepage() - invalidate a journal page
+ * @journal: journal to use for flush
  * @page:    page to flush
  * @offset:  length of page to invalidate.
  *
  * Reap page buffers containing data after offset in page.
- *
  */
 void journal_invalidatepage(journal_t *journal,
                      struct page *page,
@@ -1963,7 +2036,7 @@ void __journal_file_buffer(struct journal_head *jh,
 
        J_ASSERT_JH(jh, jh->b_jlist < BJ_Types);
        J_ASSERT_JH(jh, jh->b_transaction == transaction ||
-                               jh->b_transaction == 0);
+                               jh->b_transaction == NULL);
 
        if (jh->b_transaction && jh->b_jlist == jlist)
                return;
@@ -2067,7 +2140,7 @@ void __journal_refile_buffer(struct journal_head *jh)
        jh->b_transaction = jh->b_next_transaction;
        jh->b_next_transaction = NULL;
        __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)