simplify checks for I_CLEAR/I_FREEING

add I_CLEAR instead of replacing I_FREEING with it.  I_CLEAR is
equivalent to I_FREEING for almost all code looking at either;
it's there to keep track of having called clear_inode() exactly
once per inode lifetime, at some point after having set I_FREEING.
I_CLEAR and I_FREEING never get set at the same time with the
current code, so we can switch to setting i_flags to I_FREEING | I_CLEAR
instead of I_CLEAR without loss of information.  As the result of
such change, checks become simpler and the amount of code that needs
to know about I_CLEAR shrinks a lot.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

11 files changed, 27 insertions, 28 deletions

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 7f9e0536db1a..95eac0116963 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -3860,7 +3860,7 @@ again:
                         p = &parent->rb_right;
                 else {
                         WARN_ON(!(entry->vfs_inode.i_state &
-                                  (I_WILL_FREE | I_FREEING | I_CLEAR)));
+                                  (I_WILL_FREE | I_FREEING)));
                         rb_erase(parent, &root->inode_tree);
                         RB_CLEAR_NODE(parent);
                         spin_unlock(&root->inode_lock);
diff --git a/fs/drop_caches.c b/fs/drop_caches.c
index 83c4f600786a..2195c213ab2f 100644
--- a/fs/drop_caches.c
+++ b/fs/drop_caches.c
@@ -18,7 +18,7 @@ static void drop_pagecache_sb(struct super_block *sb, void *unused)
 
         spin_lock(&inode_lock);
         list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
-                if (inode->i_state & (I_FREEING|I_CLEAR|I_WILL_FREE|I_NEW))
+                if (inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW))
                         continue;
                 if (inode->i_mapping->nrpages == 0)
                         continue;
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index d5be1693ac93..7608880b5c58 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -352,7 +352,7 @@ writeback_single_inode(struct inode *inode, struct writeback_control *wbc)
 
         spin_lock(&inode_lock);
         inode->i_state &= ~I_SYNC;
-        if (!(inode->i_state & (I_FREEING | I_CLEAR))) {
+        if (!(inode->i_state & I_FREEING)) {
                 if ((inode->i_state & I_DIRTY_PAGES) && wbc->for_kupdate) {
                         /*
                          * More pages get dirtied by a fast dirtier.
@@ -499,7 +499,7 @@ static int writeback_sb_inodes(struct super_block *sb, struct bdi_writeback *wb,
                 if (inode_dirtied_after(inode, wbc->wb_start))
                         return 1;
 
-                BUG_ON(inode->i_state & (I_FREEING | I_CLEAR));
+                BUG_ON(inode->i_state & I_FREEING);
                 __iget(inode);
                 pages_skipped = wbc->pages_skipped;
                 writeback_single_inode(inode, wbc);
@@ -935,7 +935,7 @@ void __mark_inode_dirty(struct inode *inode, int flags)
                         if (hlist_unhashed(&inode->i_hash))
                                 goto out;
                 }
-                if (inode->i_state & (I_FREEING|I_CLEAR))
+                if (inode->i_state & I_FREEING)
                         goto out;
 
                 /*
@@ -1001,7 +1001,7 @@ static void wait_sb_inodes(struct super_block *sb)
         list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
                 struct address_space *mapping;
 
-                if (inode->i_state & (I_FREEING|I_CLEAR|I_WILL_FREE|I_NEW))
+                if (inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW))
                         continue;
                 mapping = inode->i_mapping;
                 if (mapping->nrpages == 0)
diff --git a/fs/gfs2/inode.c b/fs/gfs2/inode.c
index 6c023a3b5d25..08140f185a37 100644
--- a/fs/gfs2/inode.c
+++ b/fs/gfs2/inode.c
@@ -84,7 +84,7 @@ static int iget_skip_test(struct inode *inode, void *opaque)
         struct gfs2_skip_data *data = opaque;
 
         if (ip->i_no_addr == data->no_addr) {
-                if (inode->i_state & (I_FREEING|I_CLEAR|I_WILL_FREE)){
+                if (inode->i_state & (I_FREEING|I_WILL_FREE)){
                         data->skipped = 1;
                         return 0;
                 }
diff --git a/fs/inode.c b/fs/inode.c
index 722860b323a9..71fe079ca32a 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -317,7 +317,7 @@ void clear_inode(struct inode *inode)
                 bd_forget(inode);
         if (S_ISCHR(inode->i_mode) && inode->i_cdev)
                 cd_forget(inode);
-        inode->i_state = I_CLEAR;
+        inode->i_state = I_FREEING | I_CLEAR;
 }
 EXPORT_SYMBOL(clear_inode);
 
@@ -553,7 +553,7 @@ repeat:
                         continue;
                 if (!test(inode, data))
                         continue;
-                if (inode->i_state & (I_FREEING|I_CLEAR|I_WILL_FREE)) {
+                if (inode->i_state & (I_FREEING|I_WILL_FREE)) {
                         __wait_on_freeing_inode(inode);
                         goto repeat;
                 }
@@ -578,7 +578,7 @@ repeat:
                         continue;
                 if (inode->i_sb != sb)
                         continue;
-                if (inode->i_state & (I_FREEING|I_CLEAR|I_WILL_FREE)) {
+                if (inode->i_state & (I_FREEING|I_WILL_FREE)) {
                         __wait_on_freeing_inode(inode);
                         goto repeat;
                 }
@@ -840,7 +840,7 @@ EXPORT_SYMBOL(iunique);
 struct inode *igrab(struct inode *inode)
 {
         spin_lock(&inode_lock);
-        if (!(inode->i_state & (I_FREEING|I_CLEAR|I_WILL_FREE)))
+        if (!(inode->i_state & (I_FREEING|I_WILL_FREE)))
                 __iget(inode);
         else
                 /*
@@ -1089,7 +1089,7 @@ int insert_inode_locked(struct inode *inode)
                                 continue;
                         if (old->i_sb != sb)
                                 continue;
-                        if (old->i_state & (I_FREEING|I_CLEAR|I_WILL_FREE))
+                        if (old->i_state & (I_FREEING|I_WILL_FREE))
                                 continue;
                         break;
                 }
@@ -1128,7 +1128,7 @@ int insert_inode_locked4(struct inode *inode, unsigned long hashval,
                                 continue;
                         if (!test(old, data))
                                 continue;
-                        if (old->i_state & (I_FREEING|I_CLEAR|I_WILL_FREE))
+                        if (old->i_state & (I_FREEING|I_WILL_FREE))
                                 continue;
                         break;
                 }
@@ -1218,7 +1218,7 @@ void generic_delete_inode(struct inode *inode)
         hlist_del_init(&inode->i_hash);
         spin_unlock(&inode_lock);
         wake_up_inode(inode);
-        BUG_ON(inode->i_state != I_CLEAR);
+        BUG_ON(inode->i_state != (I_FREEING | I_CLEAR));
         destroy_inode(inode);
 }
 EXPORT_SYMBOL(generic_delete_inode);
@@ -1322,7 +1322,7 @@ static inline void iput_final(struct inode *inode)
 void iput(struct inode *inode)
 {
         if (inode) {
-                BUG_ON(inode->i_state == I_CLEAR);
+                BUG_ON(inode->i_state & I_CLEAR);
 
                 if (atomic_dec_and_lock(&inode->i_count, &inode_lock))
                         iput_final(inode);
diff --git a/fs/nilfs2/gcdat.c b/fs/nilfs2/gcdat.c
index dd5f7e0a95f6..84a45d1d5464 100644
--- a/fs/nilfs2/gcdat.c
+++ b/fs/nilfs2/gcdat.c
@@ -78,7 +78,7 @@ void nilfs_clear_gcdat_inode(struct the_nilfs *nilfs)
         struct inode *gcdat = nilfs->ns_gc_dat;
         struct nilfs_inode_info *gii = NILFS_I(gcdat);
 
-        gcdat->i_state = I_CLEAR;
+        gcdat->i_state = I_FREEING | I_CLEAR;
         gii->i_flags = 0;
 
         nilfs_palloc_clear_cache(gcdat);
diff --git a/fs/notify/inode_mark.c b/fs/notify/inode_mark.c
index 0399bcbe09c8..152b83ec005d 100644
--- a/fs/notify/inode_mark.c
+++ b/fs/notify/inode_mark.c
@@ -369,11 +369,11 @@ void fsnotify_unmount_inodes(struct list_head *list)
                 struct inode *need_iput_tmp;
 
                 /*
-                 * We cannot __iget() an inode in state I_CLEAR, I_FREEING,
+                 * We cannot __iget() an inode in state I_FREEING,
                  * I_WILL_FREE, or I_NEW which is fine because by that point
                  * the inode cannot have any associated watches.
                  */
-                if (inode->i_state & (I_CLEAR|I_FREEING|I_WILL_FREE|I_NEW))
+                if (inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW))
                         continue;
 
                 /*
@@ -397,7 +397,7 @@ void fsnotify_unmount_inodes(struct list_head *list)
                 /* In case the dropping of a reference would nuke next_i. */
                 if ((&next_i->i_sb_list != list) &&
                     atomic_read(&next_i->i_count) &&
-                    !(next_i->i_state & (I_CLEAR | I_FREEING | I_WILL_FREE))) {
+                    !(next_i->i_state & (I_FREEING | I_WILL_FREE))) {
                         __iget(next_i);
                         need_iput = next_i;
                 }
diff --git a/fs/notify/inotify/inotify.c b/fs/notify/inotify/inotify.c
index 27b75ebc7460..cf6b0429a257 100644
--- a/fs/notify/inotify/inotify.c
+++ b/fs/notify/inotify/inotify.c
@@ -377,11 +377,11 @@ void inotify_unmount_inodes(struct list_head *list)
                 struct list_head *watches;
 
                 /*
-                 * We cannot __iget() an inode in state I_CLEAR, I_FREEING,
+                 * We cannot __iget() an inode in state I_FREEING,
                  * I_WILL_FREE, or I_NEW which is fine because by that point
                  * the inode cannot have any associated watches.
                  */
-                if (inode->i_state & (I_CLEAR|I_FREEING|I_WILL_FREE|I_NEW))
+                if (inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW))
                         continue;
 
                 /*
@@ -403,8 +403,7 @@ void inotify_unmount_inodes(struct list_head *list)
                 /* In case the dropping of a reference would nuke next_i. */
                 if ((&next_i->i_sb_list != list) &&
                                 atomic_read(&next_i->i_count) &&
-                                !(next_i->i_state & (I_CLEAR | I_FREEING |
-                                        I_WILL_FREE))) {
+                                !(next_i->i_state & (I_FREEING|I_WILL_FREE))) {
                         __iget(next_i);
                         need_iput = next_i;
                 }
diff --git a/fs/quota/dquot.c b/fs/quota/dquot.c
index 437d2ca2de97..5cec3e2348f1 100644
--- a/fs/quota/dquot.c
+++ b/fs/quota/dquot.c
@@ -885,7 +885,7 @@ static void add_dquot_ref(struct super_block *sb, int type)
 
         spin_lock(&inode_lock);
         list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
-                if (inode->i_state & (I_FREEING|I_CLEAR|I_WILL_FREE|I_NEW))
+                if (inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW))
                         continue;
 #ifdef CONFIG_QUOTA_DEBUG
                 if (unlikely(inode_get_rsv_space(inode) > 0))
diff --git a/fs/xfs/linux-2.6/xfs_iops.c b/fs/xfs/linux-2.6/xfs_iops.c
index 62dd349facee..68be25dcd301 100644
--- a/fs/xfs/linux-2.6/xfs_iops.c
+++ b/fs/xfs/linux-2.6/xfs_iops.c
@@ -80,7 +80,7 @@ xfs_mark_inode_dirty_sync(
 {
         struct inode    *inode = VFS_I(ip);
 
-        if (!(inode->i_state & (I_WILL_FREE|I_FREEING|I_CLEAR)))
+        if (!(inode->i_state & (I_WILL_FREE|I_FREEING)))
                 mark_inode_dirty_sync(inode);
 }
 
@@ -90,7 +90,7 @@ xfs_mark_inode_dirty(
 {
         struct inode    *inode = VFS_I(ip);
 
-        if (!(inode->i_state & (I_WILL_FREE|I_FREEING|I_CLEAR)))
+        if (!(inode->i_state & (I_WILL_FREE|I_FREEING)))
                 mark_inode_dirty(inode);
 }
 
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 5547b1b027db..218693d8d446 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1616,8 +1616,8 @@ 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              Set by clear_inode().  In this state the inode is clean
- *                      and can be destroyed.
+ * 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