[JFFS2] Fix inode allocation race (7d200960) · Commits · e / devices / android_kernel_fairphone_FP3

fs/jffs2/README.Locking

+5 −1

Original line number	Original line	Diff line number	Diff line
	$Id: README.Locking,v 1.9 2004/11/20 10:35:40 dwmw2 Exp $		$Id: README.Locking,v 1.12 2005/04/13 13:22:35 dwmw2 Exp $

	JFFS2 LOCKING DOCUMENTATION		JFFS2 LOCKING DOCUMENTATION
	---------------------------		---------------------------
	@@ -108,6 +108,10 @@ in-core jffs2_inode_cache objects (each inode in JFFS2 has the
	correspondent jffs2_inode_cache object). So, the inocache_lock		correspondent jffs2_inode_cache object). So, the inocache_lock
	has to be locked while walking the c->inocache_list hash buckets.		has to be locked while walking the c->inocache_list hash buckets.

			This spinlock also covers allocation of new inode numbers, which is
			currently just '++->highest_ino++', but might one day get more complicated
			if we need to deal with wrapping after 4 milliard inode numbers are used.

	Note, the f->sem guarantees that the correspondent jffs2_inode_cache		Note, the f->sem guarantees that the correspondent jffs2_inode_cache
	will not be removed. So, it is allowed to access it without locking		will not be removed. So, it is allowed to access it without locking
	the inocache_lock spinlock.		the inocache_lock spinlock.

+5 −1

Original line number	Original line	Diff line number	Diff line
	@@ -7,7 +7,7 @@
	*		*
	* For licensing information, see the file 'LICENCE' in this directory.		* For licensing information, see the file 'LICENCE' in this directory.
	*		*
	* $Id: nodelist.c,v 1.93 2005/02/27 23:01:32 dwmw2 Exp $		* $Id: nodelist.c,v 1.94 2005/04/13 13:22:35 dwmw2 Exp $
	*		*
	*/		*/

	@@ -491,6 +491,10 @@ void jffs2_add_ino_cache (struct jffs2_sb_info c, struct jffs2_inode_cache new
	struct jffs2_inode_cache **prev;		struct jffs2_inode_cache **prev;
	D2(printk(KERN_DEBUG "jffs2_add_ino_cache: Add %p (ino #%u)\n", new, new->ino));		D2(printk(KERN_DEBUG "jffs2_add_ino_cache: Add %p (ino #%u)\n", new, new->ino));
	spin_lock(&c->inocache_lock);		spin_lock(&c->inocache_lock);
			if (!new->ino)
			new->ino = ++c->highest_ino;

			D2(printk(KERN_DEBUG "jffs2_add_ino_cache: Add %p (ino #%u)\n", new, new->ino));

	prev = &c->inocache_list[new->ino % INOCACHE_HASHSIZE];		prev = &c->inocache_list[new->ino % INOCACHE_HASHSIZE];

+3 −4

Original line number	Original line	Diff line number	Diff line
	@@ -7,7 +7,7 @@
	*		*
	* For licensing information, see the file 'LICENCE' in this directory.		* For licensing information, see the file 'LICENCE' in this directory.
	*		*
	* $Id: write.c,v 1.91 2005/03/01 10:34:03 dedekind Exp $		* $Id: write.c,v 1.92 2005/04/13 13:22:35 dwmw2 Exp $
	*		*
	*/		*/

	@@ -35,13 +35,12 @@ int jffs2_do_new_inode(struct jffs2_sb_info c, struct jffs2_inode_info f, uint
	f->inocache = ic;		f->inocache = ic;
	f->inocache->nlink = 1;		f->inocache->nlink = 1;
	f->inocache->nodes = (struct jffs2_raw_node_ref *)f->inocache;		f->inocache->nodes = (struct jffs2_raw_node_ref *)f->inocache;
	f->inocache->ino = ++c->highest_ino;
	f->inocache->state = INO_STATE_PRESENT;		f->inocache->state = INO_STATE_PRESENT;

	ri->ino = cpu_to_je32(f->inocache->ino);

	D1(printk(KERN_DEBUG "jffs2_do_new_inode(): Assigned ino# %d\n", f->inocache->ino));
	jffs2_add_ino_cache(c, f->inocache);		jffs2_add_ino_cache(c, f->inocache);
			D1(printk(KERN_DEBUG "jffs2_do_new_inode(): Assigned ino# %d\n", f->inocache->ino));
			ri->ino = cpu_to_je32(f->inocache->ino);

	ri->magic = cpu_to_je16(JFFS2_MAGIC_BITMASK);		ri->magic = cpu_to_je16(JFFS2_MAGIC_BITMASK);
	ri->nodetype = cpu_to_je16(JFFS2_NODETYPE_INODE);		ri->nodetype = cpu_to_je16(JFFS2_NODETYPE_INODE);