/*
* Make sure target_dir is fully connected to the dentry tree.
*
- * It may already be, as the flag isn't always updated when connection happens.
+ * On successful return, DCACHE_DISCONNECTED will be cleared on
+ * target_dir, and target_dir->d_parent->...->d_parent will reach the
+ * root of the filesystem.
+ *
+ * Whenever DCACHE_DISCONNECTED is unset, target_dir is fully connected.
+ * But the converse is not true: target_dir may have DCACHE_DISCONNECTED
+ * set but already be connected. In that case we'll verify the
+ * connection to root and then clear the flag.
+ *
+ * Note that target_dir could be removed by a concurrent operation. In
+ * that case reconnect_path may still succeed with target_dir fully
+ * connected, but further operations using the filehandle will fail when
+ * necessary (due to S_DEAD being set on the directory).
*/
static int
reconnect_path(struct vfsmount *mnt, struct dentry *target_dir, char *nbuf)
while (target_dir->d_flags & DCACHE_DISCONNECTED && noprogress++ < 10) {
struct dentry *pd = find_disconnected_root(target_dir);
+ BUG_ON(pd == mnt->mnt_sb->s_root);
+
if (!IS_ROOT(pd)) {
/* must have found a connected parent - great */
spin_lock(&pd->d_lock);
pd->d_flags &= ~DCACHE_DISCONNECTED;
spin_unlock(&pd->d_lock);
noprogress = 0;
- } else if (pd == mnt->mnt_sb->s_root) {
- printk(KERN_ERR "export: Eeek filesystem root is not connected, impossible\n");
- spin_lock(&pd->d_lock);
- pd->d_flags &= ~DCACHE_DISCONNECTED;
- spin_unlock(&pd->d_lock);
- noprogress = 0;
} else {
/*
* We have hit the top of a disconnected path, try to
struct dir_context ctx;
char *name; /* name that was found. It already points to a
buffer NAME_MAX+1 is size */
- unsigned long ino; /* the inum we are looking for */
+ u64 ino; /* the inum we are looking for */
int found; /* inode matched? */
int sequence; /* sequence counter */
};
struct inode *dir = path->dentry->d_inode;
int error;
struct file *file;
+ struct kstat stat;
+ struct path child_path = {
+ .mnt = path->mnt,
+ .dentry = child,
+ };
struct getdents_callback buffer = {
.ctx.actor = filldir_one,
.name = name,
- .ino = child->d_inode->i_ino
};
error = -ENOTDIR;
error = -EINVAL;
if (!dir->i_fop)
goto out;
+ /*
+ * inode->i_ino is unsigned long, kstat->ino is u64, so the
+ * former would be insufficient on 32-bit hosts when the
+ * filesystem supports 64-bit inode numbers. So we need to
+ * actually call ->getattr, not just read i_ino:
+ */
+ error = vfs_getattr_nosec(&child_path, &stat);
+ if (error)
+ return error;
+ buffer.ino = stat.ino;
/*
* Open the directory ...
*/