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-rw-r--r--fs/autofs4/root.c23
1 files changed, 19 insertions, 4 deletions
diff --git a/fs/autofs4/root.c b/fs/autofs4/root.c
index 47adf270106a..b4631046867e 100644
--- a/fs/autofs4/root.c
+++ b/fs/autofs4/root.c
@@ -655,14 +655,29 @@ static struct dentry *autofs4_lookup(struct inode *dir, struct dentry *dentry, s
/*
* If this dentry is unhashed, then we shouldn't honour this
- * lookup even if the dentry is positive. Returning ENOENT here
- * doesn't do the right thing for all system calls, but it should
- * be OK for the operations we permit from an autofs.
+ * lookup. Returning ENOENT here doesn't do the right thing
+ * for all system calls, but it should be OK for the operations
+ * we permit from an autofs.
*/
if (dentry->d_inode && d_unhashed(dentry)) {
+ /*
+ * A user space application can (and has done in the past)
+ * remove and re-create this directory during the callback.
+ * This can leave us with an unhashed dentry, but a
+ * successful mount! So we need to perform another
+ * cached lookup in case the dentry now exists.
+ */
+ struct dentry *parent = dentry->d_parent;
+ struct dentry *new = d_lookup(parent, &dentry->d_name);
+ if (new != NULL)
+ dentry = new;
+ else
+ dentry = ERR_PTR(-ENOENT);
+
if (unhashed)
dput(unhashed);
- return ERR_PTR(-ENOENT);
+
+ return dentry;
}
if (unhashed)