Merge tag 'writeback' of git://git.kernel.org/pub/scm/linux/kernel/git/wfg/linux

Pull writeback tree from Wu Fengguang:
 "Mainly from Jan Kara to avoid iput() in the flusher threads."

* tag 'writeback' of git://git.kernel.org/pub/scm/linux/kernel/git/wfg/linux:
  writeback: Avoid iput() from flusher thread
  vfs: Rename end_writeback() to clear_inode()
  vfs: Move waiting for inode writeback from end_writeback() to evict_inode()
  writeback: Refactor writeback_single_inode()
  writeback: Remove wb->list_lock from writeback_single_inode()
  writeback: Separate inode requeueing after writeback
  writeback: Move I_DIRTY_PAGES handling
  writeback: Move requeueing when I_SYNC set to writeback_sb_inodes()
  writeback: Move clearing of I_SYNC into inode_sync_complete()
  writeback: initialize global_dirty_limit
  fs: remove 8 bytes of padding from struct writeback_control on 64 bit builds
  mm: page-writeback.c: local functions should not be exposed globally

3 files changed, 39 insertions, 20 deletions

diff --git a/include/linux/fs.h b/include/linux/fs.h
index c0e53372b082..cdc1a9630948 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1764,8 +1764,8 @@ struct super_operations {
  * I_FREEING            Set when inode is about to be freed but still has dirty
  *                      pages or buffers attached or the inode itself is still
  *                      dirty.
- * I_CLEAR              Added by end_writeback().  In this state the inode is clean
- *                      and can be destroyed.  Inode keeps I_FREEING.
+ * I_CLEAR              Added by clear_inode().  In this state the inode is
+ *                      clean and can be destroyed.  Inode keeps I_FREEING.
  *
  *                      Inodes that are I_WILL_FREE, I_FREEING or I_CLEAR are
  *                      prohibited for many purposes.  iget() must wait for
@@ -1773,9 +1773,10 @@ struct super_operations {
  *                      anew.  Other functions will just ignore such inodes,
  *                      if appropriate.  I_NEW is used for waiting.
  *
- * I_SYNC               Synchonized write of dirty inode data.  The bits is
- *                      set during data writeback, and cleared with a wakeup
- *                      on the bit address once it is done.
+ * I_SYNC               Writeback of inode is running. The bit is set during
+ *                      data writeback, and cleared with a wakeup on the bit
+ *                      address once it is done. The bit is also used to pin
+ *                      the inode in memory for flusher thread.
  *
  * I_REFERENCED         Marks the inode as recently references on the LRU list.
  *
@@ -2349,7 +2350,7 @@ extern unsigned int get_next_ino(void);
 
 extern void __iget(struct inode * inode);
 extern void iget_failed(struct inode *);
-extern void end_writeback(struct inode *);
+extern void clear_inode(struct inode *);
 extern void __destroy_inode(struct inode *);
 extern struct inode *new_inode_pseudo(struct super_block *sb);
 extern struct inode *new_inode(struct super_block *sb);
diff --git a/include/linux/writeback.h b/include/linux/writeback.h
index a2b84f598e2b..6d0a0fcd80e7 100644
--- a/include/linux/writeback.h
+++ b/include/linux/writeback.h
@@ -58,7 +58,6 @@ extern const char *wb_reason_name[];
  * in a manner such that unspecified fields are set to zero.
  */
 struct writeback_control {
-        enum writeback_sync_modes sync_mode;
         long nr_to_write;               /* Write this many pages, and decrement
                                            this for each page written */
         long pages_skipped;             /* Pages which were not written */
@@ -71,6 +70,8 @@ struct writeback_control {
         loff_t range_start;
         loff_t range_end;
 
+        enum writeback_sync_modes sync_mode;
+
         unsigned for_kupdate:1;         /* A kupdate writeback */
         unsigned for_background:1;      /* A background writeback */
         unsigned tagged_writepages:1;   /* tag-and-write to avoid livelock */
@@ -94,6 +95,7 @@ long writeback_inodes_wb(struct bdi_writeback *wb, long nr_pages,
                                 enum wb_reason reason);
 long wb_do_writeback(struct bdi_writeback *wb, int force_wait);
 void wakeup_flusher_threads(long nr_pages, enum wb_reason reason);
+void inode_wait_for_writeback(struct inode *inode);
 
 /* writeback.h requires fs.h; it, too, is not included from here. */
 static inline void wait_on_inode(struct inode *inode)
@@ -101,12 +103,6 @@ static inline void wait_on_inode(struct inode *inode)
         might_sleep();
         wait_on_bit(&inode->i_state, __I_NEW, inode_wait, TASK_UNINTERRUPTIBLE);
 }
-static inline void inode_sync_wait(struct inode *inode)
-{
-        might_sleep();
-        wait_on_bit(&inode->i_state, __I_SYNC, inode_wait,
-                                                        TASK_UNINTERRUPTIBLE);
-}
 
 
 /*
diff --git a/include/trace/events/writeback.h b/include/trace/events/writeback.h
index 7b81887b023f..b453d92c2253 100644
--- a/include/trace/events/writeback.h
+++ b/include/trace/events/writeback.h
@@ -372,6 +372,35 @@ TRACE_EVENT(balance_dirty_pages,
           )
 );
 
+TRACE_EVENT(writeback_sb_inodes_requeue,
+
+        TP_PROTO(struct inode *inode),
+        TP_ARGS(inode),
+
+        TP_STRUCT__entry(
+                __array(char, name, 32)
+                __field(unsigned long, ino)
+                __field(unsigned long, state)
+                __field(unsigned long, dirtied_when)
+        ),
+
+        TP_fast_assign(
+                strncpy(__entry->name,
+                        dev_name(inode_to_bdi(inode)->dev), 32);
+                __entry->ino            = inode->i_ino;
+                __entry->state          = inode->i_state;
+                __entry->dirtied_when   = inode->dirtied_when;
+        ),
+
+        TP_printk("bdi %s: ino=%lu state=%s dirtied_when=%lu age=%lu",
+                  __entry->name,
+                  __entry->ino,
+                  show_inode_state(__entry->state),
+                  __entry->dirtied_when,
+                  (jiffies - __entry->dirtied_when) / HZ
+        )
+);
+
 DECLARE_EVENT_CLASS(writeback_congest_waited_template,
 
         TP_PROTO(unsigned int usec_timeout, unsigned int usec_delayed),
@@ -450,13 +479,6 @@ DECLARE_EVENT_CLASS(writeback_single_inode_template,
         )
 );
 
-DEFINE_EVENT(writeback_single_inode_template, writeback_single_inode_requeue,
-        TP_PROTO(struct inode *inode,
-                 struct writeback_control *wbc,
-                 unsigned long nr_to_write),
-        TP_ARGS(inode, wbc, nr_to_write)
-);
-
 DEFINE_EVENT(writeback_single_inode_template, writeback_single_inode,
         TP_PROTO(struct inode *inode,
                  struct writeback_control *wbc,