Inode: Allow external list initialisation

To allow XFS to combine the XFS and linux inodes into a single structure, we need to drive inode lookup from the XFS inode cache, not the generic inode cache. This means that we need initialise a struct inode from a context outside alloc_inode() as it is no longer used by XFS. After inode allocation and initialisation, we need to add the inode to the superblock list, the in-use list, hash it and do some accounting. This all needs to be done with the inode_lock held and there are already several places in fs/inode.c that do this list manipulation. Factor out the common code, add a locking wrapper and export the function so ti can be called from XFS. Signed-off-by: Dave Chinner <david@fromorbit.com> Signed-off-by: Christoph Hellwig <hch@infradead.org> Signed-off-by: Lachlan McIlroy <lachlan@sgi.com>

Inode: Allow external list initialisation
To allow XFS to combine the XFS and linux inodes into a single structure, we need to drive inode lookup from the XFS inode cache, not the generic inode cache. This means that we need initialise a struct inode from a context outside alloc_inode() as it is no longer used by XFS. After inode allocation and initialisation, we need to add the inode to the superblock list, the in-use list, hash it and do some accounting. This all needs to be done with the inode_lock held and there are already several places in fs/inode.c that do this list manipulation. Factor out the common code, add a locking wrapper and export the function so ti can be called from XFS. Signed-off-by: Dave Chinner <david@fromorbit.com> Signed-off-by: Christoph Hellwig <hch@infradead.org> Signed-off-by: Lachlan McIlroy <lachlan@sgi.com>
David Chinner · Lachlan McIlroy
1 parent 2cb1599f9b
Showing 2 changed files with 47 additions and 21 deletions Side-by-side Diff
fs/inode.c
include/linux/fs.h
@@ -550,7 +550,50 @@
 	return node ? inode : NULL;
 }
  
+static unsigned long hash(struct super_block *sb, unsigned long hashval)
+{
+	unsigned long tmp;
+
+	tmp = (hashval * (unsigned long)sb) ^ (GOLDEN_RATIO_PRIME + hashval) /
+			L1_CACHE_BYTES;
+	tmp = tmp ^ ((tmp ^ GOLDEN_RATIO_PRIME) >> I_HASHBITS);
+	return tmp & I_HASHMASK;
+}
+
+static inline void
+__inode_add_to_lists(struct super_block *sb, struct hlist_head *head,
+			struct inode *inode)
+{
+	inodes_stat.nr_inodes++;
+	list_add(&inode->i_list, &inode_in_use);
+	list_add(&inode->i_sb_list, &sb->s_inodes);
+	if (head)
+		hlist_add_head(&inode->i_hash, head);
+}
+
 /**
+ * inode_add_to_lists - add a new inode to relevant lists
+ * @sb		- superblock inode belongs to.
+ * @inode	- inode to mark in use
+ *
+ * When an inode is allocated it needs to be accounted for, added to the in use
+ * list, the owning superblock and the inode hash. This needs to be done under
+ * the inode_lock, so export a function to do this rather than the inode lock
+ * itself. We calculate the hash list to add to here so it is all internal
+ * which requires the caller to have already set up the inode number in the
+ * inode to add.
+ */
+void inode_add_to_lists(struct super_block *sb, struct inode *inode)
+{
+	struct hlist_head *head = inode_hashtable + hash(sb, inode->i_ino);
+
+	spin_lock(&inode_lock);
+	__inode_add_to_lists(sb, head, inode);
+	spin_unlock(&inode_lock);
+}
+EXPORT_SYMBOL_GPL(inode_add_to_lists);
+
+/**
  *	new_inode 	- obtain an inode
  *	@sb: superblock
  *
@@ -577,9 +620,7 @@
 	inode = alloc_inode(sb);
 	if (inode) {
 		spin_lock(&inode_lock);
-		inodes_stat.nr_inodes++;
-		list_add(&inode->i_list, &inode_in_use);
-		list_add(&inode->i_sb_list, &sb->s_inodes);
+		__inode_add_to_lists(sb, NULL, inode);
 		inode->i_ino = ++last_ino;
 		inode->i_state = 0;
 		spin_unlock(&inode_lock);
@@ -638,10 +679,7 @@
 			if (set(inode, data))
 				goto set_failed;
  
-			inodes_stat.nr_inodes++;
-			list_add(&inode->i_list, &inode_in_use);
-			list_add(&inode->i_sb_list, &sb->s_inodes);
-			hlist_add_head(&inode->i_hash, head);
+			__inode_add_to_lists(sb, head, inode);
 			inode->i_state = I_LOCK|I_NEW;
 			spin_unlock(&inode_lock);
  
@@ -687,10 +725,7 @@
 		old = find_inode_fast(sb, head, ino);
 		if (!old) {
 			inode->i_ino = ino;
-			inodes_stat.nr_inodes++;
-			list_add(&inode->i_list, &inode_in_use);
-			list_add(&inode->i_sb_list, &sb->s_inodes);
-			hlist_add_head(&inode->i_hash, head);
+			__inode_add_to_lists(sb, head, inode);
 			inode->i_state = I_LOCK|I_NEW;
 			spin_unlock(&inode_lock);
  
@@ -712,16 +747,6 @@
 		wait_on_inode(inode);
 	}
 	return inode;
-}
-
-static unsigned long hash(struct super_block *sb, unsigned long hashval)
-{
-	unsigned long tmp;
-
-	tmp = (hashval * (unsigned long)sb) ^ (GOLDEN_RATIO_PRIME + hashval) /
-			L1_CACHE_BYTES;
-	tmp = tmp ^ ((tmp ^ GOLDEN_RATIO_PRIME) >> I_HASHBITS);
-	return tmp & I_HASHMASK;
 }
  
 /**
@@ -1883,6 +1883,7 @@
  
 extern struct inode * inode_init_always(struct super_block *, struct inode *);
 extern void inode_init_once(struct inode *);
+extern void inode_add_to_lists(struct super_block *, struct inode *);
 extern void iput(struct inode *);
 extern struct inode * igrab(struct inode *);
 extern ino_t iunique(struct super_block *, ino_t);
...	...	@@ -550,7 +550,50 @@
550	550	return node ? inode : NULL;
551	551	}
552	552
	553	+static unsigned long hash(struct super_block *sb, unsigned long hashval)
	554	+{
	555	+ unsigned long tmp;
	556	+
	557	+ tmp = (hashval * (unsigned long)sb) ^ (GOLDEN_RATIO_PRIME + hashval) /
	558	+ L1_CACHE_BYTES;
	559	+ tmp = tmp ^ ((tmp ^ GOLDEN_RATIO_PRIME) >> I_HASHBITS);
	560	+ return tmp & I_HASHMASK;
	561	+}
	562	+
	563	+static inline void
	564	+__inode_add_to_lists(struct super_block sb, struct hlist_head head,
	565	+ struct inode *inode)
	566	+{
	567	+ inodes_stat.nr_inodes++;
	568	+ list_add(&inode->i_list, &inode_in_use);
	569	+ list_add(&inode->i_sb_list, &sb->s_inodes);
	570	+ if (head)
	571	+ hlist_add_head(&inode->i_hash, head);
	572	+}
	573	+
553	574	/**
	575	+ * inode_add_to_lists - add a new inode to relevant lists
	576	+ * @sb - superblock inode belongs to.
	577	+ * @inode - inode to mark in use
	578	+ *
	579	+ * When an inode is allocated it needs to be accounted for, added to the in use
	580	+ * list, the owning superblock and the inode hash. This needs to be done under
	581	+ * the inode_lock, so export a function to do this rather than the inode lock
	582	+ * itself. We calculate the hash list to add to here so it is all internal
	583	+ * which requires the caller to have already set up the inode number in the
	584	+ * inode to add.
	585	+ */
	586	+void inode_add_to_lists(struct super_block sb, struct inode inode)
	587	+{
	588	+ struct hlist_head *head = inode_hashtable + hash(sb, inode->i_ino);
	589	+
	590	+ spin_lock(&inode_lock);
	591	+ __inode_add_to_lists(sb, head, inode);
	592	+ spin_unlock(&inode_lock);
	593	+}
	594	+EXPORT_SYMBOL_GPL(inode_add_to_lists);
	595	+
	596	+/**
554	597	* new_inode - obtain an inode
555	598	* @sb: superblock
556	599	*
...	...	@@ -577,9 +620,7 @@
577	620	inode = alloc_inode(sb);
578	621	if (inode) {
579	622	spin_lock(&inode_lock);
580		- inodes_stat.nr_inodes++;
581		- list_add(&inode->i_list, &inode_in_use);
582		- list_add(&inode->i_sb_list, &sb->s_inodes);
	623	+ __inode_add_to_lists(sb, NULL, inode);
583	624	inode->i_ino = ++last_ino;
584	625	inode->i_state = 0;
585	626	spin_unlock(&inode_lock);
...	...	@@ -638,10 +679,7 @@
638	679	if (set(inode, data))
639	680	goto set_failed;
640	681
641		- inodes_stat.nr_inodes++;
642		- list_add(&inode->i_list, &inode_in_use);
643		- list_add(&inode->i_sb_list, &sb->s_inodes);
644		- hlist_add_head(&inode->i_hash, head);
	682	+ __inode_add_to_lists(sb, head, inode);
645	683	inode->i_state = I_LOCK\|I_NEW;
646	684	spin_unlock(&inode_lock);
647	685
...	...	@@ -687,10 +725,7 @@
687	725	old = find_inode_fast(sb, head, ino);
688	726	if (!old) {
689	727	inode->i_ino = ino;
690		- inodes_stat.nr_inodes++;
691		- list_add(&inode->i_list, &inode_in_use);
692		- list_add(&inode->i_sb_list, &sb->s_inodes);
693		- hlist_add_head(&inode->i_hash, head);
	728	+ __inode_add_to_lists(sb, head, inode);
694	729	inode->i_state = I_LOCK\|I_NEW;
695	730	spin_unlock(&inode_lock);
696	731
...	...	@@ -712,16 +747,6 @@
712	747	wait_on_inode(inode);
713	748	}
714	749	return inode;
715		-}
716		-
717		-static unsigned long hash(struct super_block *sb, unsigned long hashval)
718		-{
719		- unsigned long tmp;
720		-
721		- tmp = (hashval * (unsigned long)sb) ^ (GOLDEN_RATIO_PRIME + hashval) /
722		- L1_CACHE_BYTES;
723		- tmp = tmp ^ ((tmp ^ GOLDEN_RATIO_PRIME) >> I_HASHBITS);
724		- return tmp & I_HASHMASK;
725	750	}
726	751
727	752	/**
...	...	@@ -1883,6 +1883,7 @@
1883	1883
1884	1884	extern struct inode * inode_init_always(struct super_block , struct inode );
1885	1885	extern void inode_init_once(struct inode *);
	1886	+extern void inode_add_to_lists(struct super_block , struct inode );
1886	1887	extern void iput(struct inode *);
1887	1888	extern struct inode * igrab(struct inode *);
1888	1889	extern ino_t iunique(struct super_block *, ino_t);