mem: cdev lock_kernel() pushdown

[safe/jmp/linux-2.6] / fs / fs-writeback.c

diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index 3fe782d..ae45f77 100644 (file)
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -25,6 +25,45 @@
 #include <linux/buffer_head.h>
 #include "internal.h"
 
+
+/**
+ * writeback_acquire - attempt to get exclusive writeback access to a device
+ * @bdi: the device's backing_dev_info structure
+ *
+ * It is a waste of resources to have more than one pdflush thread blocked on
+ * a single request queue.  Exclusion at the request_queue level is obtained
+ * via a flag in the request_queue's backing_dev_info.state.
+ *
+ * Non-request_queue-backed address_spaces will share default_backing_dev_info,
+ * unless they implement their own.  Which is somewhat inefficient, as this
+ * may prevent concurrent writeback against multiple devices.
+ */
+static int writeback_acquire(struct backing_dev_info *bdi)
+{
+       return !test_and_set_bit(BDI_pdflush, &bdi->state);
+}
+
+/**
+ * writeback_in_progress - determine whether there is writeback in progress
+ * @bdi: the device's backing_dev_info structure.
+ *
+ * Determine whether there is writeback in progress against a backing device.
+ */
+int writeback_in_progress(struct backing_dev_info *bdi)
+{
+       return test_bit(BDI_pdflush, &bdi->state);
+}
+
+/**
+ * writeback_release - relinquish exclusive writeback access against a device.
+ * @bdi: the device's backing_dev_info structure
+ */
+static void writeback_release(struct backing_dev_info *bdi)
+{
+       BUG_ON(!writeback_in_progress(bdi));
+       clear_bit(BDI_pdflush, &bdi->state);
+}
+
 /**
  *     __mark_inode_dirty -    internal function
  *     @inode: inode to mark
@@ -284,7 +323,17 @@ __sync_single_inode(struct inode *inode, struct writeback_control *wbc)
                                 * soon as the queue becomes uncongested.
                                 */
                                inode->i_state |= I_DIRTY_PAGES;
-                               requeue_io(inode);
+                               if (wbc->nr_to_write <= 0) {
+                                       /*
+                                        * slice used up: queue for next turn
+                                        */
+                                       requeue_io(inode);
+                               } else {
+                                       /*
+                                        * somehow blocked: retry later
+                                        */
+                                       redirty_tail(inode);
+                               }
                        } else {
                                /*
                                 * Otherwise fully redirty the inode so that
@@ -468,8 +517,12 @@ sync_sb_inodes(struct super_block *sb, struct writeback_control *wbc)
                iput(inode);
                cond_resched();
                spin_lock(&inode_lock);
-               if (wbc->nr_to_write <= 0)
+               if (wbc->nr_to_write <= 0) {
+                       wbc->more_io = 1;
                        break;
+               }
+               if (!list_empty(&sb->s_more_io))
+                       wbc->more_io = 1;
        }
        return;         /* Leave any unwritten inodes on s_io */
 }
@@ -501,8 +554,7 @@ writeback_inodes(struct writeback_control *wbc)
        might_sleep();
        spin_lock(&sb_lock);
 restart:
-       sb = sb_entry(super_blocks.prev);
-       for (; sb != sb_entry(&super_blocks); sb = sb_entry(sb->s_list.prev)) {
+       list_for_each_entry_reverse(sb, &super_blocks, s_list) {
                if (sb_has_dirty_inodes(sb)) {
                        /* we're making our own get_super here */
                        sb->s_count++;
@@ -567,10 +619,8 @@ static void set_sb_syncing(int val)
 {
        struct super_block *sb;
        spin_lock(&sb_lock);
-       sb = sb_entry(super_blocks.prev);
-       for (; sb != sb_entry(&super_blocks); sb = sb_entry(sb->s_list.prev)) {
+       list_for_each_entry_reverse(sb, &super_blocks, s_list)
                sb->s_syncing = val;
-       }
        spin_unlock(&sb_lock);
 }
 
@@ -644,7 +694,7 @@ int write_inode_now(struct inode *inode, int sync)
        int ret;
        struct writeback_control wbc = {
                .nr_to_write = LONG_MAX,
-               .sync_mode = WB_SYNC_ALL,
+               .sync_mode = sync ? WB_SYNC_ALL : WB_SYNC_NONE,
                .range_start = 0,
                .range_end = LLONG_MAX,
        };
@@ -736,43 +786,4 @@ int generic_osync_inode(struct inode *inode, struct address_space *mapping, int
 
        return err;
 }
-
 EXPORT_SYMBOL(generic_osync_inode);
-
-/**
- * writeback_acquire: attempt to get exclusive writeback access to a device
- * @bdi: the device's backing_dev_info structure
- *
- * It is a waste of resources to have more than one pdflush thread blocked on
- * a single request queue.  Exclusion at the request_queue level is obtained
- * via a flag in the request_queue's backing_dev_info.state.
- *
- * Non-request_queue-backed address_spaces will share default_backing_dev_info,
- * unless they implement their own.  Which is somewhat inefficient, as this
- * may prevent concurrent writeback against multiple devices.
- */
-int writeback_acquire(struct backing_dev_info *bdi)
-{
-       return !test_and_set_bit(BDI_pdflush, &bdi->state);
-}
-
-/**
- * writeback_in_progress: determine whether there is writeback in progress
- * @bdi: the device's backing_dev_info structure.
- *
- * Determine whether there is writeback in progress against a backing device.
- */
-int writeback_in_progress(struct backing_dev_info *bdi)
-{
-       return test_bit(BDI_pdflush, &bdi->state);
-}
-
-/**
- * writeback_release: relinquish exclusive writeback access against a device.
- * @bdi: the device's backing_dev_info structure
- */
-void writeback_release(struct backing_dev_info *bdi)
-{
-       BUG_ON(!writeback_in_progress(bdi));
-       clear_bit(BDI_pdflush, &bdi->state);
-}