extern void
mvfs_linux_umount_begin(
struct vfsmount * mnt,
int flags
)
#endif
{
VNODE_T *vp;
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,18) || \
LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,27)
struct vfsmount *mnt;
#else
/*
* Since 2.6.18 and before 2.6.27 we have mnt as a parameter.
* But we still need super_p.
*/
SUPER_T *super_p = mnt->mnt_sb;
#endif
#if LINUX_VERSION_CODE < KERNEL_VERSION(3,3,0)
int mount_count = 0;
#endif
ASSERT(super_p != NULL);
ASSERT(super_p->s_root != NULL);
vp = ITOV(super_p->s_root->d_inode);
ASSERT(vp != NULL);
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,18) || \
LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,27)
mnt = VTOVFSMNT(vp);
#else
/* Check that the mountpoint passed in matches the one
* from the vp that we are going to clear. Skip it otherwise.
* We know from experience that this can happen when unmounting
* loopback (bind) mounts.
*/
if (mnt != VTOVFSMNT(vp))
return;
#endif
/* Note that there is no mechanism for restoring the mount pointer
* in the vnode if an error happens later on in the umount. This is
* the only callback into the mvfs during umount. So far this has not
* been a problem and if we don't do this here, the umount will never
* succeed because the Linux code expects the mnt_count to be 2.
* The count is 3 at this point from the initial allocation of the
* vfsmnt structure, the path_lookup call in this umount call and
* from when we placed the pointer in the vp.
*/
if (mnt == NULL) {
MDKI_VFS_LOG(VFS_LOG_ERR, "%s: mnt is NULL\n", __FUNCTION__);
return;
}
#if LINUX_VERSION_CODE < KERNEL_VERSION(3,3,0)
mount_count = MDKI_READ_MNT_COUNT(mnt);
if (mount_count == 3) {
MDKI_MNTPUT(mnt);
SET_VTOVFSMNT(vp, NULL);
}
#else
/*
* may_umount returns !0 when the ref counter is 2 (and other conditions).
* We took an extra ref, I'll drop it to test may_umount. If it is not
* ready to be unmounted, the put is reverted.
*/
MDKI_MNTPUT(mnt);
if (may_umount(mnt)) {
SET_VTOVFSMNT(vp, NULL);
} else {
/* not ready yet */
MDKI_MNTGET(mnt);
}
#endif /* LINUX_VERSION_CODE < KERNEL_VERSION(3,3,0) */
}
extern void
mvfs_linux_umount_begin(
struct vfsmount * mnt,
int flags
)
#endif
{
VNODE_T *vp;
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,18) || \
LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,27)
struct vfsmount *mnt;
#else
/*
* Since 2.6.18 and before 2.6.27 we have mnt as a parameter.
* But we still need super_p.
*/
SUPER_T *super_p = mnt->mnt_sb;
#endif
int mount_count = 0;
#if (LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,38)) && defined(CONFIG_SMP)
int cpu;
#endif
ASSERT(super_p != NULL);
ASSERT(super_p->s_root != NULL);
vp = ITOV(super_p->s_root->d_inode);
ASSERT(vp != NULL);
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,18) || \
LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,27)
mnt = VTOVFSMNT(vp);
#else
/* Check that the mountpoint passed in matches the one
* from the vp that we are going to clear. Skip it otherwise.
* We know from experience that this can happen when unmounting
* loopback (bind) mounts.
*/
if (mnt != VTOVFSMNT(vp))
return;
#endif
/* Note that there is no mechanism for restoring the mount pointer
* in the vnode if an error happens later on in the umount. This is
* the only callback into the mvfs during umount. So far this has not
* been a problem and if we don't do this here, the umount will never
* succeed because the Linux code expects the mnt_count to be 2.
* The count is 3 at this point from the initial allocation of the
* vfsmnt structure, the path_lookup call in this umount call and
* from when we placed the pointer in the vp.
*/
if (mnt == NULL) {
MDKI_VFS_LOG(VFS_LOG_ERR, "%s: mnt is NULL\n", __FUNCTION__);
return;
}
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,38)
mount_count = atomic_read(&mnt->mnt_count);
#else
# ifdef CONFIG_SMP
br_read_lock(vfsmount_lock);
for_each_possible_cpu(cpu) {
mount_count += per_cpu_ptr(mnt->mnt_pcp, cpu)->mnt_count;
}
br_read_unlock(vfsmount_lock);
# else /* CONFIG_SMP */
mount_count = mnt->mnt_count;
# endif /* else CONFIG_SMP */
#endif /* else < KERNEL_VERSION(2,6,38) */
if (mount_count == 3) {
MDKI_MNTPUT(mnt);
SET_VTOVFSMNT(vp, NULL);
}
}
