On Tue, 26 Mar 2002, Mike Galbraith wrote:
> On Sat, 23 Mar 2002, Alexander Viro wrote:
>
> > There are known problems with rm(1) on ramfs/tmpfs/etc. - the thing assumes
> > that offsets in directory remain stable after unlink(2), but locking changes
> > didn't affect.
>
> Ok, I finally found a wee bit of clue. I understand the assumption,
> and in virgin 2.5.4, that assumption is enforced... somefsckingwhere ;-)
I suppose that doesn't matter much though, since the assumption working
still doesn't make it right. (mentioned it because I can't figure out
why the behavior changed despite MUCH reading.. seemed odd/reportable)
Anyway, the hack below seems to work fine. Is there a better way?
-Mike
--- fs/libfs.c.org Sun Mar 24 13:20:39 2002
+++ fs/libfs.c Wed Mar 27 10:46:13 2002
@@ -29,6 +29,21 @@
return 0;
}
+static int seek_ok(struct dentry *dir, int offset)
+{
+ struct list_head *list;
+ int count = 2;
+
+ list = dir->d_subdirs.next;
+
+ while(list != &dir->d_subdirs) {
+ list = list->next;
+ count++;
+ }
+
+ return offset > count;
+}
+
/*
* Directory is locked and all positive dentries in it are safe, since
* for ramfs-type trees they can't go away without unlink() or rmdir(),
@@ -37,10 +52,9 @@
int dcache_readdir(struct file * filp, void * dirent, filldir_t filldir)
{
- int i;
+ int i = filp->f_pos;
struct dentry *dentry = filp->f_dentry;
- i = filp->f_pos;
switch (i) {
case 0:
if (filldir(dirent, ".", 1, i, dentry->d_inode->i_ino, DT_DIR) < 0)
@@ -57,11 +71,17 @@
default: {
struct list_head *list;
int j = i-2;
+ int abort;
spin_lock(&dcache_lock);
list = dentry->d_subdirs.next;
+ /*
+ * HACK: if we're attempting to seek _past_ the last
+ * entry, the directory is being modified. Abort seek.
+ */
+ abort = seek_ok(dentry, i);
- for (;;) {
+ for (;!abort;) {
if (list == &dentry->d_subdirs) {
spin_unlock(&dcache_lock);
return 0;
-
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This archive was generated by hypermail 2b29 : Sun Mar 31 2002 - 22:00:13 EST