Messages in this thread | | | Date | Tue, 20 May 2008 09:34:57 -0600 | From | Matthew Wilcox <> | Subject | Re: [RFC PATCH] Introduce filesystem type tracking |
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On Tue, May 20, 2008 at 04:18:14PM +0100, Tom Spink wrote: > + > + mutex_lock(&type->fs_supers_lock); > + if (list_empty(&type->fs_supers) && type->init) { > + err = type->init(); > + if (err) { > + mutex_unlock(&type->fs_supers_lock); > + spin_unlock(&sb_lock); > + destroy_super(s); > + return ERR_PTR(err); > + } > + } > + > + list_add(&s->s_instances, &type->fs_supers); > + mutex_unlock(&type->fs_supers_lock); > + > s->s_type = type; > strlcpy(s->s_id, type->name, sizeof(s->s_id)); > list_add_tail(&s->s_list, &super_blocks); > - list_add(&s->s_instances, &type->fs_supers); > + > spin_unlock(&sb_lock);
You can't take a mutex while holding a spinlock -- what if you had to sleep to acquire the mutex?
I imagine you also don't want to hold a spinlock while calling the ->init or ->exit -- what if the fs wants to sleep in there (eg allocate memory with GFP_KERNEL).
-- Intel are signing my paycheques ... these opinions are still mine "Bill, look, we understand that you're interested in selling us this operating system, but compare it to ours. We can't possibly take such a retrograde step."
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