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[JFFS2] Fix inode allocation race 

Signed-off-by: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
David Woodhouse 2005-04-13 14:22:38 +01:00 committed by Thomas Gleixner
parent 0a18cde60f
commit 7d200960d4
3 changed files with 13 additions and 6 deletions
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6
fs/jffs2/README.Locking
View File

@ -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 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.

6
fs/jffs2/nodelist.c
View File

@ -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];

7
fs/jffs2/write.c
View File

@ -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);