On Sat, 30 Mar 2002, Mike Galbraith wrote:
> Hi,
>
> d_delete() doesn't appear to ever create negative dentries when
> called via vfs_unlink() due to the extra reference on the dentry.
> In fact, a printk() in the d_delete() spot never ever triggers...
Well shoot. I guess I've chased this about as far as I can, and
hope this thread wasn't a total waste. I found a better way to
get my rm -r to work as before fwiw. Rewinding the directory on
seek failure (yeah, could do in three lines, but not the point)
works, but is kinda b0rken. I think the only interesting thing
in the below is the FIXME :)) but I'll post it anyway.
EOT,
-Mike
Private comments on this quite welcome. Locking is a bitch :-)
--- fs/dcache.c.org Sat Mar 30 12:27:34 2002
+++ fs/dcache.c Sat Mar 30 17:32:43 2002
@@ -803,7 +803,10 @@
* @dentry: The dentry to delete
*
* Turn the dentry into a negative dentry if possible, otherwise
- * remove it from the hash queues so it can be deleted later
+ * remove it from the hash queues so it can be deleted later.
+ * FIXME: this assumes more than GOD allows :)
+ * This function must be called while holding an extra reference
+ * to the dentry, and with the dentry's d_inode pinned down.
*/
void d_delete(struct dentry * dentry)
@@ -812,7 +815,7 @@
* Are we the only user?
*/
spin_lock(&dcache_lock);
- if (atomic_read(&dentry->d_count) == 1) {
+ if (atomic_read(&dentry->d_count) == 2) {
dentry_iput(dentry);
return;
}
--- fs/namei.c.org Sat Mar 30 12:54:29 2002
+++ fs/namei.c Sat Mar 30 17:17:02 2002
@@ -1453,6 +1453,7 @@
int vfs_unlink(struct inode *dir, struct dentry *dentry)
{
int error = may_delete(dir, dentry, 0);
+ struct inode *inode;
if (error)
return error;
@@ -1463,7 +1464,12 @@
DQUOT_INIT(dir);
dget(dentry);
- down(&dentry->d_inode->i_sem);
+ inode = igrab(dentry->d_inode);
+ if (!inode) {
+ dput(dentry);
+ return -EBUSY;
+ }
+ down(&inode->i_sem);
if (d_mountpoint(dentry))
error = -EBUSY;
else {
@@ -1471,7 +1477,10 @@
if (!error)
d_delete(dentry);
}
- up(&dentry->d_inode->i_sem);
+ if (inode) {
+ up(&inode->i_sem);
+ iput(inode);
+ }
dput(dentry);
if (!error)
(Hmm. Actually, rewinding on seek failure is a more useful lie
than a NULL when the thing ain't empty, so I think I'll go apply
the three liner again and see if anything gripes)
-
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This archive was generated by hypermail 2b29 : Sun Mar 31 2002 - 22:00:19 EST