static void au_do_unlock(const unsigned char dmsg, struct au_mvd_args *a)
{
if (!a->rename_lock) {
mutex_unlock(&a->mvd_h_src_dir->i_mutex);
au_unpin(&a->pin);
} else
vfsub_unlock_rename(a->mvd_h_src_parent, a->mvd_hdir_src,
a->mvd_h_dst_parent, a->mvd_hdir_dst);
}
/*
* locking order
* (VFS)
* - src_dir and dir by lock_rename()
* - inode if exitsts
* (aufs)
* - lock all
* + src_dentry and dentry by aufs_read_and_write_lock2() which calls,
* + si_read_lock
* + di_write_lock2_child()
* + di_write_lock_child()
* + ii_write_lock_child()
* + di_write_lock_child2()
* + ii_write_lock_child2()
* + src_parent and parent
* + di_write_lock_parent()
* + ii_write_lock_parent()
* + di_write_lock_parent2()
* + ii_write_lock_parent2()
* + lower src_dir and dir by vfsub_lock_rename()
* + verify the every relationships between child and parent. if any
* of them failed, unlock all and return -EBUSY.
*/
static void au_ren_unlock(struct au_ren_args *a)
{
struct super_block *sb;
sb = a->dst_dentry->d_sb;
if (au_ftest_ren(a->flags, MNT_WRITE))
mnt_drop_write(a->br->br_mnt);
vfsub_unlock_rename(a->src_h_parent, a->src_hdir,
a->dst_h_parent, a->dst_hdir);
}
static void au_do_unlock(const unsigned char dmsg, struct au_mvd_args *a)
{
if (!a->rename_lock)
au_unpin(&a->mvd_pin_src);
else {
vfsub_unlock_rename(a->mvd_h_src_parent, a->mvd_hdir_src,
a->mvd_h_dst_parent, a->mvd_hdir_dst);
au_pin_hdir_lock(&a->mvd_pin_src);
au_unpin(&a->mvd_pin_src);
au_pin_hdir_lock(&a->mvd_pin_dst);
}
au_unpin(&a->mvd_pin_dst);
}
/* lock them all */
static int au_do_lock(const unsigned char dmsg, struct au_mvd_args *a)
{
int err;
struct dentry *h_trap;
a->mvd_h_src_sb = au_sbr_sb(a->sb, a->mvd_bsrc);
a->mvd_h_dst_sb = au_sbr_sb(a->sb, a->mvd_bdst);
err = au_pin(&a->mvd_pin_dst, a->dentry, a->mvd_bdst,
au_opt_udba(a->sb),
AuPin_MNT_WRITE | AuPin_DI_LOCKED);
AuTraceErr(err);
if (unlikely(err)) {
AU_MVD_PR(dmsg, "pin_dst failed\n");
goto out;
}
if (a->mvd_h_src_sb != a->mvd_h_dst_sb) {
a->rename_lock = 0;
au_pin_init(&a->mvd_pin_src, a->dentry, a->mvd_bsrc,
AuLsc_DI_PARENT, AuLsc_I_PARENT3,
au_opt_udba(a->sb),
AuPin_MNT_WRITE | AuPin_DI_LOCKED);
err = au_do_pin(&a->mvd_pin_src);
AuTraceErr(err);
a->mvd_h_src_dir = d_inode(a->mvd_h_src_parent);
if (unlikely(err)) {
AU_MVD_PR(dmsg, "pin_src failed\n");
goto out_dst;
}
goto out; /* success */
}
a->rename_lock = 1;
au_pin_hdir_unlock(&a->mvd_pin_dst);
err = au_pin(&a->mvd_pin_src, a->dentry, a->mvd_bsrc,
au_opt_udba(a->sb),
AuPin_MNT_WRITE | AuPin_DI_LOCKED);
AuTraceErr(err);
a->mvd_h_src_dir = d_inode(a->mvd_h_src_parent);
if (unlikely(err)) {
AU_MVD_PR(dmsg, "pin_src failed\n");
au_pin_hdir_lock(&a->mvd_pin_dst);
goto out_dst;
}
au_pin_hdir_unlock(&a->mvd_pin_src);
h_trap = vfsub_lock_rename(a->mvd_h_src_parent, a->mvd_hdir_src,
a->mvd_h_dst_parent, a->mvd_hdir_dst);
if (h_trap) {
err = (h_trap != a->mvd_h_src_parent);
if (err)
err = (h_trap != a->mvd_h_dst_parent);
}
BUG_ON(err); /* it should never happen */
if (unlikely(a->mvd_h_src_dir != au_pinned_h_dir(&a->mvd_pin_src))) {
err = -EBUSY;
AuTraceErr(err);
vfsub_unlock_rename(a->mvd_h_src_parent, a->mvd_hdir_src,
a->mvd_h_dst_parent, a->mvd_hdir_dst);
au_pin_hdir_lock(&a->mvd_pin_src);
au_unpin(&a->mvd_pin_src);
au_pin_hdir_lock(&a->mvd_pin_dst);
goto out_dst;
}
goto out; /* success */
out_dst:
au_unpin(&a->mvd_pin_dst);
out:
AuTraceErr(err);
return err;
}
