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>

9 files changed, 39 insertions, 44 deletions

diff --git a/fs/gfs2/inode.c b/fs/gfs2/inode.c
index 3ff32fa793da..6e220f4eee7d 100644
--- a/fs/gfs2/inode.c
+++ b/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)
diff --git a/fs/inode.c b/fs/inode.c
index 06c1f02de611..03dfeb2e3928 100644
--- a/fs/inode.c
+++ b/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();
diff --git a/fs/jfs/jfs_txnmgr.c b/fs/jfs/jfs_txnmgr.c
index f26e4d03ada5..d945ea76b445 100644
--- a/fs/jfs/jfs_txnmgr.c
+++ b/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
diff --git a/fs/ntfs/inode.c b/fs/ntfs/inode.c
index 9938034762cc..dc2505abb6d7 100644
--- a/fs/ntfs/inode.c
+++ b/fs/ntfs/inode.c
@@ -530,7 +530,7 @@ err_corrupt_attr:
  * 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 @@ err_out:
  * 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 @@ err_out:
  * 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
diff --git a/fs/ubifs/file.c b/fs/ubifs/file.c
index 39849f887e72..16a6444330ec 100644
--- a/fs/ubifs/file.c
+++ b/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.
  */
 
diff --git a/fs/xfs/linux-2.6/xfs_iops.c b/fs/xfs/linux-2.6/xfs_iops.c
index 1d5b298ba8b2..225946012d0b 100644
--- a/fs/xfs/linux-2.6/xfs_iops.c
+++ b/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;
diff --git a/fs/xfs/xfs_iget.c b/fs/xfs/xfs_iget.c
index 0de36c2a46f1..fa402a6bbbcf 100644
--- a/fs/xfs/xfs_iget.c
+++ b/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)) {
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 77a975089d9a..cca191933ff6 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 705f01fe413a..c18c008f4bbf 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)
 {