Skip to content

Commit

Permalink
[JFFS2] Fix inode allocation race
Browse files Browse the repository at this point in the history
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
  • Loading branch information
David Woodhouse authored and Thomas Gleixner committed May 23, 2005
1 parent 0a18cde commit 7d20096
Show file tree
Hide file tree
Showing 3 changed files with 13 additions and 6 deletions.
6 changes: 5 additions & 1 deletion fs/jffs2/README.Locking
Original file line number Diff line number Diff line change
@@ -1,4 +1,4 @@
$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
---------------------------
Expand Down Expand Up @@ -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
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
will not be removed. So, it is allowed to access it without locking
the inocache_lock spinlock.
Expand Down
6 changes: 5 additions & 1 deletion fs/jffs2/nodelist.c
Original file line number Diff line number Diff line change
Expand Up @@ -7,7 +7,7 @@
*
* 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 $
*
*/

Expand Down Expand Up @@ -491,6 +491,10 @@ void jffs2_add_ino_cache (struct jffs2_sb_info *c, struct jffs2_inode_cache *new
struct jffs2_inode_cache **prev;
D2(printk(KERN_DEBUG "jffs2_add_ino_cache: Add %p (ino #%u)\n", new, new->ino));
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];

Expand Down
7 changes: 3 additions & 4 deletions fs/jffs2/write.c
Original file line number Diff line number Diff line change
Expand Up @@ -7,7 +7,7 @@
*
* 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 $
*
*/

Expand Down Expand Up @@ -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->nlink = 1;
f->inocache->nodes = (struct jffs2_raw_node_ref *)f->inocache;
f->inocache->ino = ++c->highest_ino;
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);
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->nodetype = cpu_to_je16(JFFS2_NODETYPE_INODE);
Expand Down

0 comments on commit 7d20096

Please sign in to comment.