luck/tmp_suning_uos_patched
1
0
Fork 1
Code Issues Pull Requests Packages Projects Releases Wiki Activity

CacheFiles: Better showing of debugging information in active object problems

Browse Source 
Show more debugging information if cachefiles_mark_object_active() is asked to
activate an active object.

This may happen, for instance, if the netfs tries to register an object with
the same key multiple times.

The code is changed to (a) get the appropriate object lock to protect the
cookie pointer whilst we dereference it, and (b) get and display the cookie key
if available.

Signed-off-by: David Howells <dhowells@redhat.com>
This commit is contained in:
David Howells 2009-11-19 18:12:02 +00:00
parent 6511de33c8
commit d0e27b7808
1 changed files with 75 additions and 27 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

102
fs/cachefiles/namei.c
View File

@ -27,6 +27,76 @@ static int cachefiles_wait_bit(void *flags)
return 0;
}
#define CACHEFILES_KEYBUF_SIZE 512
/*
* dump debugging info about an object
*/
static noinline
void __cachefiles_printk_object(struct cachefiles_object *object,
const char *prefix,
u8 *keybuf)
{
struct fscache_cookie *cookie;
unsigned keylen, loop;
printk(KERN_ERR "%sobject: OBJ%x\n",
prefix, object->fscache.debug_id);
printk(KERN_ERR "%sobjstate=%s fl=%lx swfl=%lx ev=%lx[%lx]\n",
prefix, fscache_object_states[object->fscache.state],
object->fscache.flags, object->fscache.work.flags,
object->fscache.events,
object->fscache.event_mask & FSCACHE_OBJECT_EVENTS_MASK);
printk(KERN_ERR "%sops=%u inp=%u exc=%u\n",
prefix, object->fscache.n_ops, object->fscache.n_in_progress,
object->fscache.n_exclusive);
printk(KERN_ERR "%sparent=%p\n",
prefix, object->fscache.parent);
spin_lock(&object->fscache.lock);
cookie = object->fscache.cookie;
if (cookie) {
printk(KERN_ERR "%scookie=%p [pr=%p nd=%p fl=%lx]\n",
prefix,
object->fscache.cookie,
object->fscache.cookie->parent,
object->fscache.cookie->netfs_data,
object->fscache.cookie->flags);
if (keybuf)
keylen = cookie->def->get_key(cookie->netfs_data, keybuf,
CACHEFILES_KEYBUF_SIZE);
else
keylen = 0;
} else {
printk(KERN_ERR "%scookie=NULL\n", prefix);
keylen = 0;
}
spin_unlock(&object->fscache.lock);
if (keylen) {
printk(KERN_ERR "%skey=[%u] '", prefix, keylen);
for (loop = 0; loop < keylen; loop++)
printk("%02x", keybuf[loop]);
printk("'\n");
}
}
/*
* dump debugging info about a pair of objects
*/
static noinline void cachefiles_printk_object(struct cachefiles_object *object,
struct cachefiles_object *xobject)
{
u8 *keybuf;
keybuf = kmalloc(CACHEFILES_KEYBUF_SIZE, GFP_NOIO);
if (object)
__cachefiles_printk_object(object, "", keybuf);
if (xobject)
__cachefiles_printk_object(xobject, "x", keybuf);
kfree(keybuf);
}
/*
* record the fact that an object is now active
*/
@ -42,8 +112,11 @@ static void cachefiles_mark_object_active(struct cachefiles_cache *cache,
try_again:
write_lock(&cache->active_lock);
if (test_and_set_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags))
if (test_and_set_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags)) {
printk(KERN_ERR "CacheFiles: Error: Object already active\n");
cachefiles_printk_object(object, NULL);
BUG();
}
dentry = object->dentry;
_p = &cache->active_nodes.rb_node;
@ -76,32 +149,7 @@ static void cachefiles_mark_object_active(struct cachefiles_cache *cache,
printk(KERN_ERR "\n");
printk(KERN_ERR "CacheFiles: Error:"
" Unexpected object collision\n");
printk(KERN_ERR "xobject: OBJ%x\n",
xobject->fscache.debug_id);
printk(KERN_ERR "xobjstate=%s\n",
fscache_object_states[xobject->fscache.state]);
printk(KERN_ERR "xobjflags=%lx\n", xobject->fscache.flags);
printk(KERN_ERR "xobjevent=%lx [%lx]\n",
xobject->fscache.events, xobject->fscache.event_mask);
printk(KERN_ERR "xops=%u inp=%u exc=%u\n",
xobject->fscache.n_ops, xobject->fscache.n_in_progress,
xobject->fscache.n_exclusive);
printk(KERN_ERR "xcookie=%p [pr=%p nd=%p fl=%lx]\n",
xobject->fscache.cookie,
xobject->fscache.cookie->parent,
xobject->fscache.cookie->netfs_data,
xobject->fscache.cookie->flags);
printk(KERN_ERR "xparent=%p\n",
xobject->fscache.parent);
printk(KERN_ERR "object: OBJ%x\n",
object->fscache.debug_id);
printk(KERN_ERR "cookie=%p [pr=%p nd=%p fl=%lx]\n",
object->fscache.cookie,
object->fscache.cookie->parent,
object->fscache.cookie->netfs_data,
object->fscache.cookie->flags);
printk(KERN_ERR "parent=%p\n",
object->fscache.parent);
cachefiles_printk_object(object, xobject);
BUG();
}
atomic_inc(&xobject->usage);