1 files changed, 54 insertions, 88 deletions

diff --git a/fs/inode.c b/fs/inode.c
index 6b4c77268fc0..01ebdc40021e 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -184,7 +184,7 @@ static int proc_nr_inodes(const struct ctl_table *table, int write, void *buffer
 	return proc_doulongvec_minmax(table, write, buffer, lenp, ppos);
 }
 
-static struct ctl_table inodes_sysctls[] = {
+static const struct ctl_table inodes_sysctls[] = {
 	{
 		.procname	= "inode-nr",
 		.data		= &inodes_stat,
@@ -327,7 +327,17 @@ static void i_callback(struct rcu_head *head)
 		free_inode_nonrcu(inode);
 }
 
-static struct inode *alloc_inode(struct super_block *sb)
+/**
+ *	alloc_inode 	- obtain an inode
+ *	@sb: superblock
+ *
+ *	Allocates a new inode for given superblock.
+ *	Inode wont be chained in superblock s_inodes list
+ *	This means :
+ *	- fs can't be unmount
+ *	- quotas, fsnotify, writeback can't work
+ */
+struct inode *alloc_inode(struct super_block *sb)
 {
 	const struct super_operations *ops = sb->s_op;
 	struct inode *inode;
@@ -613,18 +623,22 @@ static void inode_wait_for_lru_isolating(struct inode *inode)
  */
 void inode_sb_list_add(struct inode *inode)
 {
-	spin_lock(&inode->i_sb->s_inode_list_lock);
-	list_add(&inode->i_sb_list, &inode->i_sb->s_inodes);
-	spin_unlock(&inode->i_sb->s_inode_list_lock);
+	struct super_block *sb = inode->i_sb;
+
+	spin_lock(&sb->s_inode_list_lock);
+	list_add(&inode->i_sb_list, &sb->s_inodes);
+	spin_unlock(&sb->s_inode_list_lock);
 }
 EXPORT_SYMBOL_GPL(inode_sb_list_add);
 
 static inline void inode_sb_list_del(struct inode *inode)
 {
+	struct super_block *sb = inode->i_sb;
+
 	if (!list_empty(&inode->i_sb_list)) {
-		spin_lock(&inode->i_sb->s_inode_list_lock);
+		spin_lock(&sb->s_inode_list_lock);
 		list_del_init(&inode->i_sb_list);
-		spin_unlock(&inode->i_sb->s_inode_list_lock);
+		spin_unlock(&sb->s_inode_list_lock);
 	}
 }
 
@@ -806,23 +820,16 @@ static void evict(struct inode *inode)
 	/*
 	 * Wake up waiters in __wait_on_freeing_inode().
 	 *
-	 * Lockless hash lookup may end up finding the inode before we removed
-	 * it above, but only lock it *after* we are done with the wakeup below.
-	 * In this case the potential waiter cannot safely block.
+	 * It is an invariant that any thread we need to wake up is already
+	 * accounted for before remove_inode_hash() acquires ->i_lock -- both
+	 * sides take the lock and sleep is aborted if the inode is found
+	 * unhashed. Thus either the sleeper wins and goes off CPU, or removal
+	 * wins and the sleeper aborts after testing with the lock.
 	 *
-	 * The inode being unhashed after the call to remove_inode_hash() is
-	 * used as an indicator whether blocking on it is safe.
+	 * This also means we don't need any fences for the call below.
 	 */
-	spin_lock(&inode->i_lock);
-	/*
-	 * Pairs with the barrier in prepare_to_wait_event() to make sure
-	 * ___wait_var_event() either sees the bit cleared or
-	 * waitqueue_active() check in wake_up_var() sees the waiter.
-	 */
-	smp_mb__after_spinlock();
 	inode_wake_up_bit(inode, __I_NEW);
 	BUG_ON(inode->i_state != (I_FREEING | I_CLEAR));
-	spin_unlock(&inode->i_lock);
 
 	destroy_inode(inode);
 }
@@ -858,12 +865,12 @@ static void dispose_list(struct list_head *head)
  */
 void evict_inodes(struct super_block *sb)
 {
-	struct inode *inode, *next;
+	struct inode *inode;
 	LIST_HEAD(dispose);
 
 again:
 	spin_lock(&sb->s_inode_list_lock);
-	list_for_each_entry_safe(inode, next, &sb->s_inodes, i_sb_list) {
+	list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
 		if (atomic_read(&inode->i_count))
 			continue;
 
@@ -900,46 +907,6 @@ again:
 }
 EXPORT_SYMBOL_GPL(evict_inodes);
 
-/**
- * invalidate_inodes	- attempt to free all inodes on a superblock
- * @sb:		superblock to operate on
- *
- * Attempts to free all inodes (including dirty inodes) for a given superblock.
- */
-void invalidate_inodes(struct super_block *sb)
-{
-	struct inode *inode, *next;
-	LIST_HEAD(dispose);
-
-again:
-	spin_lock(&sb->s_inode_list_lock);
-	list_for_each_entry_safe(inode, next, &sb->s_inodes, i_sb_list) {
-		spin_lock(&inode->i_lock);
-		if (inode->i_state & (I_NEW | I_FREEING | I_WILL_FREE)) {
-			spin_unlock(&inode->i_lock);
-			continue;
-		}
-		if (atomic_read(&inode->i_count)) {
-			spin_unlock(&inode->i_lock);
-			continue;
-		}
-
-		inode->i_state |= I_FREEING;
-		inode_lru_list_del(inode);
-		spin_unlock(&inode->i_lock);
-		list_add(&inode->i_lru, &dispose);
-		if (need_resched()) {
-			spin_unlock(&sb->s_inode_list_lock);
-			cond_resched();
-			dispose_list(&dispose);
-			goto again;
-		}
-	}
-	spin_unlock(&sb->s_inode_list_lock);
-
-	dispose_list(&dispose);
-}
-
 /*
  * Isolate the inode from the LRU in preparation for freeing it.
  *
@@ -1160,21 +1127,6 @@ unsigned int get_next_ino(void)
 EXPORT_SYMBOL(get_next_ino);
 
 /**
- *	new_inode_pseudo 	- obtain an inode
- *	@sb: superblock
- *
- *	Allocates a new inode for given superblock.
- *	Inode wont be chained in superblock s_inodes list
- *	This means :
- *	- fs can't be unmount
- *	- quotas, fsnotify, writeback can't work
- */
-struct inode *new_inode_pseudo(struct super_block *sb)
-{
-	return alloc_inode(sb);
-}
-
-/**
  *	new_inode 	- obtain an inode
  *	@sb: superblock
  *
@@ -1190,7 +1142,7 @@ struct inode *new_inode(struct super_block *sb)
 {
 	struct inode *inode;
 
-	inode = new_inode_pseudo(sb);
+	inode = alloc_inode(sb);
 	if (inode)
 		inode_sb_list_add(inode);
 	return inode;
@@ -1206,9 +1158,8 @@ void lockdep_annotate_inode_mutex_key(struct inode *inode)
 		/* Set new key only if filesystem hasn't already changed it */
 		if (lockdep_match_class(&inode->i_rwsem, &type->i_mutex_key)) {
 			/*
-			 * ensure nobody is actually holding i_mutex
+			 * ensure nobody is actually holding i_rwsem
 			 */
-			// mutex_destroy(&inode->i_mutex);
 			init_rwsem(&inode->i_rwsem);
 			lockdep_set_class(&inode->i_rwsem,
 					  &type->i_mutex_dir_key);
@@ -1348,8 +1299,8 @@ again:
 	}
 
 	if (set && unlikely(set(inode, data))) {
-		inode = NULL;
-		goto unlock;
+		spin_unlock(&inode_hash_lock);
+		return NULL;
 	}
 
 	/*
@@ -1361,14 +1312,14 @@ again:
 	hlist_add_head_rcu(&inode->i_hash, head);
 	spin_unlock(&inode->i_lock);
 
+	spin_unlock(&inode_hash_lock);
+
 	/*
 	 * Add inode to the sb list if it's not already. It has I_NEW at this
 	 * point, so it should be safe to test i_sb_list locklessly.
 	 */
 	if (list_empty(&inode->i_sb_list))
 		inode_sb_list_add(inode);
-unlock:
-	spin_unlock(&inode_hash_lock);
 
 	return inode;
 }
@@ -1497,8 +1448,8 @@ again:
 			inode->i_state = I_NEW;
 			hlist_add_head_rcu(&inode->i_hash, head);
 			spin_unlock(&inode->i_lock);
-			inode_sb_list_add(inode);
 			spin_unlock(&inode_hash_lock);
+			inode_sb_list_add(inode);
 
 			/* Return the locked inode with I_NEW set, the
 			 * caller is responsible for filling in the contents
@@ -2663,7 +2614,7 @@ EXPORT_SYMBOL(inode_dio_finished);
  * proceed with a truncate or equivalent operation.
  *
  * Must be called under a lock that serializes taking new references
- * to i_dio_count, usually by inode->i_mutex.
+ * to i_dio_count, usually by inode->i_rwsem.
  */
 void inode_dio_wait(struct inode *inode)
 {
@@ -2681,7 +2632,7 @@ EXPORT_SYMBOL(inode_dio_wait_interruptible);
 /*
  * inode_set_flags - atomically set some inode flags
  *
- * Note: the caller should be holding i_mutex, or else be sure that
+ * Note: the caller should be holding i_rwsem exclusively, or else be sure that
  * they have exclusive access to the inode structure (i.e., while the
  * inode is being instantiated).  The reason for the cmpxchg() loop
  * --- which wouldn't be necessary if all code paths which modify
@@ -2689,7 +2640,7 @@ EXPORT_SYMBOL(inode_dio_wait_interruptible);
  * code path which doesn't today so we use cmpxchg() out of an abundance
  * of caution.
  *
- * In the long run, i_mutex is overkill, and we should probably look
+ * In the long run, i_rwsem is overkill, and we should probably look
  * at using the i_lock spinlock to protect i_flags, and then make sure
  * it is so documented in include/linux/fs.h and that all code follows
  * the locking convention!!
@@ -2953,3 +2904,18 @@ umode_t mode_strip_sgid(struct mnt_idmap *idmap,
 	return mode & ~S_ISGID;
 }
 EXPORT_SYMBOL(mode_strip_sgid);
+
+#ifdef CONFIG_DEBUG_VFS
+/*
+ * Dump an inode.
+ *
+ * TODO: add a proper inode dumping routine, this is a stub to get debug off the
+ * ground.
+ */
+void dump_inode(struct inode *inode, const char *reason)
+{
+       pr_warn("%s encountered for inode %px", reason, inode);
+}
+
+EXPORT_SYMBOL(dump_inode);
+#endif