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>

fs/gfs2/inode.c

@@ -125,7 +125,7 @@ static struct inode *gfs2_iget_skip(struct super_block *sb,
  * directory entry when gfs2_inode_lookup() is invoked. Part of the code
  * segment inside gfs2_inode_lookup code needs to get moved around.
  *
- * Clean up I_LOCK and I_NEW as well.
+ * Clears I_NEW as well.
  **/
 
 void gfs2_set_iop(struct inode *inode)

fs/inode.c

@@ -113,7 +113,7 @@ static void wake_up_inode(struct inode *inode)
 	 * Prevent speculative execution through spin_unlock(&inode_lock);
 	 */
 	smp_mb();
-	wake_up_bit(&inode->i_state, __I_LOCK);
+	wake_up_bit(&inode->i_state, __I_NEW);
 }
 
 /**
@@ -690,17 +690,17 @@ void unlock_new_inode(struct inode *inode)
 	}
 #endif
 	/*
-	 * This is special!  We do not need the spinlock when clearing I_LOCK,
+	 * This is special!  We do not need the spinlock when clearing I_NEW,
 	 * because we're guaranteed that nobody else tries to do anything about
 	 * the state of the inode when it is locked, as we just created it (so
-	 * there can be no old holders that haven't tested I_LOCK).
+	 * there can be no old holders that haven't tested I_NEW).
 	 * However we must emit the memory barrier so that other CPUs reliably
-	 * see the clearing of I_LOCK after the other inode initialisation has
+	 * see the clearing of I_NEW after the other inode initialisation has
 	 * completed.
 	 */
 	smp_mb();
-	WARN_ON((inode->i_state & (I_LOCK|I_NEW)) != (I_LOCK|I_NEW));
-	inode->i_state &= ~(I_LOCK|I_NEW);
+	WARN_ON(!(inode->i_state & I_NEW));
+	inode->i_state &= ~I_NEW;
 	wake_up_inode(inode);
 }
 EXPORT_SYMBOL(unlock_new_inode);
@@ -731,7 +731,7 @@ static struct inode *get_new_inode(struct super_block *sb,
 				goto set_failed;
 
 			__inode_add_to_lists(sb, head, inode);
-			inode->i_state = I_LOCK|I_NEW;
+			inode->i_state = I_NEW;
 			spin_unlock(&inode_lock);
 
 			/* Return the locked inode with I_NEW set, the
@@ -778,7 +778,7 @@ static struct inode *get_new_inode_fast(struct super_block *sb,
 		if (!old) {
 			inode->i_ino = ino;
 			__inode_add_to_lists(sb, head, inode);
-			inode->i_state = I_LOCK|I_NEW;
+			inode->i_state = I_NEW;
 			spin_unlock(&inode_lock);
 
 			/* Return the locked inode with I_NEW set, the
@@ -1083,7 +1083,7 @@ int insert_inode_locked(struct inode *inode)
 	ino_t ino = inode->i_ino;
 	struct hlist_head *head = inode_hashtable + hash(sb, ino);
 
-	inode->i_state |= I_LOCK|I_NEW;
+	inode->i_state |= I_NEW;
 	while (1) {
 		struct hlist_node *node;
 		struct inode *old = NULL;
@@ -1120,7 +1120,7 @@ int insert_inode_locked4(struct inode *inode, unsigned long hashval,
 	struct super_block *sb = inode->i_sb;
 	struct hlist_head *head = inode_hashtable + hash(sb, hashval);
 
-	inode->i_state |= I_LOCK|I_NEW;
+	inode->i_state |= I_NEW;
 
 	while (1) {
 		struct hlist_node *node;
@@ -1510,7 +1510,7 @@ EXPORT_SYMBOL(inode_wait);
  * until the deletion _might_ have completed.  Callers are responsible
  * to recheck inode state.
  *
- * It doesn't matter if I_LOCK is not set initially, a call to
+ * It doesn't matter if I_NEW is not set initially, a call to
  * wake_up_inode() after removing from the hash list will DTRT.
  *
  * This is called with inode_lock held.
@@ -1518,8 +1518,8 @@ EXPORT_SYMBOL(inode_wait);
 static void __wait_on_freeing_inode(struct inode *inode)
 {
 	wait_queue_head_t *wq;
-	DEFINE_WAIT_BIT(wait, &inode->i_state, __I_LOCK);
-	wq = bit_waitqueue(&inode->i_state, __I_LOCK);
+	DEFINE_WAIT_BIT(wait, &inode->i_state, __I_NEW);
+	wq = bit_waitqueue(&inode->i_state, __I_NEW);
 	prepare_to_wait(wq, &wait.wait, TASK_UNINTERRUPTIBLE);
 	spin_unlock(&inode_lock);
 	schedule();

fs/jfs/jfs_txnmgr.c

@@ -1292,7 +1292,7 @@ int txCommit(tid_t tid,		/* transaction identifier */
 		 */
 		/*
 		 * I believe this code is no longer needed.  Splitting I_LOCK
-		 * into two bits, I_LOCK and I_SYNC should prevent this
+		 * into two bits, I_NEW and I_SYNC should prevent this
 		 * deadlock as well.  But since I don't have a JFS testload
 		 * to verify this, only a trivial s/I_LOCK/I_SYNC/ was done.
 		 * Joern

fs/ntfs/inode.c

@@ -530,7 +530,7 @@ static int ntfs_is_extended_system_file(ntfs_attr_search_ctx *ctx)
  * the ntfs inode.
  *
  * Q: What locks are held when the function is called?
- * A: i_state has I_LOCK set, hence the inode is locked, also
+ * A: i_state has I_NEW set, hence the inode is locked, also
  *    i_count is set to 1, so it is not going to go away
  *    i_flags is set to 0 and we have no business touching it.  Only an ioctl()
  *    is allowed to write to them. We should of course be honouring them but
@@ -1207,7 +1207,7 @@ static int ntfs_read_locked_inode(struct inode *vi)
  * necessary fields in @vi as well as initializing the ntfs inode.
  *
  * Q: What locks are held when the function is called?
- * A: i_state has I_LOCK set, hence the inode is locked, also
+ * A: i_state has I_NEW set, hence the inode is locked, also
  *    i_count is set to 1, so it is not going to go away
  *
  * Return 0 on success and -errno on error.  In the error case, the inode will
@@ -1474,7 +1474,7 @@ static int ntfs_read_locked_attr_inode(struct inode *base_vi, struct inode *vi)
  * normal directory inodes.
  *
  * Q: What locks are held when the function is called?
- * A: i_state has I_LOCK set, hence the inode is locked, also
+ * A: i_state has I_NEW set, hence the inode is locked, also
  *    i_count is set to 1, so it is not going to go away
  *
  * Return 0 on success and -errno on error.  In the error case, the inode will

fs/ubifs/file.c

@@ -45,7 +45,7 @@
  *
  * Similarly, @i_mutex is not always locked in 'ubifs_readpage()', e.g., the
  * read-ahead path does not lock it ("sys_read -> generic_file_aio_read ->
- * ondemand_readahead -> readpage"). In case of readahead, @I_LOCK flag is not
+ * ondemand_readahead -> readpage"). In case of readahead, @I_SYNC flag is not
  * set as well. However, UBIFS disables readahead.
  */
 

fs/xfs/linux-2.6/xfs_iops.c

@@ -794,7 +794,7 @@ xfs_setup_inode(
 	struct inode		*inode = &ip->i_vnode;
 
 	inode->i_ino = ip->i_ino;
-	inode->i_state = I_NEW|I_LOCK;
+	inode->i_state = I_NEW;
 	inode_add_to_lists(ip->i_mount->m_super, inode);
 
 	inode->i_mode	= ip->i_d.di_mode;

fs/xfs/xfs_iget.c

@@ -91,7 +91,7 @@ xfs_inode_alloc(
 	ip->i_new_size = 0;
 
 	/* prevent anyone from using this yet */
-	VFS_I(ip)->i_state = I_NEW|I_LOCK;
+	VFS_I(ip)->i_state = I_NEW;
 
 	return ip;
 }
@@ -217,7 +217,7 @@ xfs_iget_cache_hit(
 			trace_xfs_iget_reclaim(ip);
 			goto out_error;
 		}
-		inode->i_state = I_LOCK|I_NEW;
+		inode->i_state = I_NEW;
 	} else {
 		/* If the VFS inode is being torn down, pause and try again. */
 		if (!igrab(inode)) {

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)

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)
 {