A Dimarts 17 Maig 2011 20:07:13, vÃreu escriure:
> Jordi, what about the original bug you reported:
> >>>- a few days ago we talked about an error when repetitive sed
> >>>instructions were executed, also it happens in other processes, like
> >>>mantaining list of installed files for actual packages,
> >>>that is solved in ovl_rename issuing a dget for the old-dentry and
> >>>parent dentries. (This code is inspired on rename.c from unionfs)
>
> Is this still happening? Does the debug patch make any difference?
my patch adds some dget/dput operations that minimize the problem, it occurs
less times, but it happens.
I suppose that those extra operations add an execution delay before processing
the main routine;
a deduction is that locking dentries is required to synchronize a rename to
not be executed until another rename operation has finished.
As an example of code that looks like that of unionfs, (this is not tested)
struct ovl_entry {
struct dentry *__upperdentry;
struct dentry *lowerdentry;
+ struct mutex d_mutex;
union {
struct {
u64 version;
bool opaque;
};
struct rcu_head rcu;
};
};
static struct ovl_entry *ovl_alloc_entry(void)
{
struct ovl_entry *oe;
oe = kzalloc(sizeof(struct ovl_entry), GFP_KERNEL);
mutex_init(&oe->d_mutex);
return oe;
}
void ovl_lock_dentry(struct dentry *dentry)
{
struct ovl_entry *oe = dentry->d_fsdata;
mutex_lock(&oe->d_mutex);
}
void ovl_unlock_dentry(struct dentry *dentry)
{
struct ovl_entry *oe = dentry->d_fsdata;
mutex_unlock(&oe->d_mutex);
}
static int ovl_rename(struct inode *olddir, struct dentry *old,
struct inode *newdir, struct dentry *new)
{
int err;
...........
+ ovl_lock_dentry(old);
err = ovl_copy_up(old);
...........
+ ovl_unlock_dentry(old);
return err;
}
consider this idea,
Thanks,
Jordi Pujol
Live never ending Tale
GNU/Linux Live forever!
http://livenet.selfip.com
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