lib/vfscore: Fix double-lock bug in symlink

This change fixes an issue where the lock of the destination parent
directory was being taken more than once in the symlink syscall by using
the locked variant of namei_last_nofollow.

Signed-off-by: Andrei Tatar <andrei@unikraft.io>
Reviewed-by: Maria Sfiraiala <maria.sfiraiala@gmail.com>
Approved-by: Razvan Deaconescu <razvand@unikraft.io>
Tested-by: Unikraft CI <monkey@unikraft.io>
GitHub-Closes: #952

diff --git a/lib/vfscore/syscalls.c b/lib/vfscore/syscalls.c
index 4b203ccd8e83e8dc46b6bd677cd2c708b368df28..21d2ac6a760deef805cc2f52c0b9de6476222494 100644 (file)
--- a/lib/vfscore/syscalls.c
+++ b/lib/vfscore/syscalls.c
@@ -908,7 +908,7 @@ sys_symlink(const char *oldpath, const char *newpath)
        vn_lock(newdirdp->d_vnode);
 
        /* newpath should not already exist */
-       if (unlikely(namei_last_nofollow(np, newdirdp, &newdp) == 0)) {
+       if (unlikely(namei_last_nofollow_locked(np, newdirdp, &newdp) == 0)) {
                drele(newdp);
                error = EEXIST;
                goto out_unlock;