kill I_LOCK

After I_SYNC was split from I_LOCK the leftover is always used together with
I_NEW and thus superflous.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

2 files changed, 17 insertions, 22 deletions

diff --git a/include/linux/fs.h b/include/linux/fs.h
index 77a9750..cca1919 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1587,7 +1587,7 @@ struct super_operations {
  * until that flag is cleared.  I_WILL_FREE, I_FREEING and I_CLEAR are set at
  * various stages of removing an inode.
  *
- * Two bits are used for locking and completion notification, I_LOCK and I_SYNC.
+ * Two bits are used for locking and completion notification, I_NEW and I_SYNC.
  *
  * I_DIRTY_SYNC		Inode is dirty, but doesn't have to be written on
  *			fdatasync().  i_atime is the usual cause.
@@ -1596,8 +1596,14 @@ struct super_operations {
  *			don't have to write inode on fdatasync() when only
  *			mtime has changed in it.
  * I_DIRTY_PAGES	Inode has dirty pages.  Inode itself may be clean.
- * I_NEW		get_new_inode() sets i_state to I_LOCK|I_NEW.  Both
- *			are cleared by unlock_new_inode(), called from iget().
+ * I_NEW		Serves as both a mutex and completion notification.
+ *			New inodes set I_NEW.  If two processes both create
+ *			the same inode, one of them will release its inode and
+ *			wait for I_NEW to be released before returning.
+ *			Inodes in I_WILL_FREE, I_FREEING or I_CLEAR state can
+ *			also cause waiting on I_NEW, without I_NEW actually
+ *			being set.  find_inode() uses this to prevent returning
+ *			nearly-dead inodes.
  * I_WILL_FREE		Must be set when calling write_inode_now() if i_count
  *			is zero.  I_FREEING must be set when I_WILL_FREE is
  *			cleared.
@@ -1611,20 +1617,11 @@ struct super_operations {
  *			prohibited for many purposes.  iget() must wait for
  *			the inode to be completely released, then create it
  *			anew.  Other functions will just ignore such inodes,
- *			if appropriate.  I_LOCK is used for waiting.
+ *			if appropriate.  I_NEW is used for waiting.
  *
- * I_LOCK		Serves as both a mutex and completion notification.
- *			New inodes set I_LOCK.  If two processes both create
- *			the same inode, one of them will release its inode and
- *			wait for I_LOCK to be released before returning.
- *			Inodes in I_WILL_FREE, I_FREEING or I_CLEAR state can
- *			also cause waiting on I_LOCK, without I_LOCK actually
- *			being set.  find_inode() uses this to prevent returning
- *			nearly-dead inodes.
- * I_SYNC		Similar to I_LOCK, but limited in scope to writeback
- *			of inode dirty data.  Having a separate lock for this
- *			purpose reduces latency and prevents some filesystem-
- *			specific deadlocks.
+ * 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.
  *
  * Q: What is the difference between I_WILL_FREE and I_FREEING?
  * Q: igrab() only checks on (I_FREEING|I_WILL_FREE).  Should it also check on
@@ -1633,13 +1630,12 @@ struct super_operations {
 #define I_DIRTY_SYNC		1
 #define I_DIRTY_DATASYNC	2
 #define I_DIRTY_PAGES		4
-#define I_NEW			8
+#define __I_NEW			3
+#define I_NEW			(1 << __I_NEW)
 #define I_WILL_FREE		16
 #define I_FREEING		32
 #define I_CLEAR			64
-#define __I_LOCK		7
-#define I_LOCK			(1 << __I_LOCK)
-#define __I_SYNC		8
+#define __I_SYNC		7
 #define I_SYNC			(1 << __I_SYNC)
 
 #define I_DIRTY (I_DIRTY_SYNC | I_DIRTY_DATASYNC | I_DIRTY_PAGES)
diff --git a/include/linux/writeback.h b/include/linux/writeback.h
index 705f01f..c18c008 100644
--- a/include/linux/writeback.h
+++ b/include/linux/writeback.h
@@ -79,8 +79,7 @@ void wakeup_flusher_threads(long nr_pages);
 static inline void wait_on_inode(struct inode *inode)
 {
 	might_sleep();
-	wait_on_bit(&inode->i_state, __I_LOCK, inode_wait,
-							TASK_UNINTERRUPTIBLE);
+	wait_on_bit(&inode->i_state, __I_NEW, inode_wait, TASK_UNINTERRUPTIBLE);
 }
 static inline void inode_sync_wait(struct inode *inode)
 {