mnt: Add filesystem private data to mount points
This starts to add private data associated directly
to mount points. The intent is to give filesystems
a sense of where they have come from, as a means of
letting a filesystem take different actions based on
this information.
Change-Id: Ie769d7b3bb2f5972afe05c1bf16cf88c91647ab2
Signed-off-by: Daniel Rosenberg <drosen@google.com>
Signed-off-by: Kevin F. Haggerty <haggertk@lineageos.org>
diff --git a/fs/namespace.c b/fs/namespace.c
index 24488a4..af36e11 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -482,6 +482,7 @@
static void free_vfsmnt(struct mount *mnt)
{
+ kfree(mnt->mnt.data);
kfree(mnt->mnt_devname);
mnt_free_id(mnt);
#ifdef CONFIG_SMP
@@ -698,11 +699,21 @@
if (!mnt)
return ERR_PTR(-ENOMEM);
+ mnt->mnt.data = NULL;
+ if (type->alloc_mnt_data) {
+ mnt->mnt.data = type->alloc_mnt_data();
+ if (!mnt->mnt.data) {
+ mnt_free_id(mnt);
+ free_vfsmnt(mnt);
+ return ERR_PTR(-ENOMEM);
+ }
+ }
if (flags & MS_KERNMOUNT)
mnt->mnt.mnt_flags = MNT_INTERNAL;
root = mount_fs(type, flags, name, data);
if (IS_ERR(root)) {
+ kfree(mnt->mnt.data);
free_vfsmnt(mnt);
return ERR_CAST(root);
}
@@ -729,6 +740,13 @@
if (!mnt)
return ERR_PTR(-ENOMEM);
+ if (sb->s_op->clone_mnt_data) {
+ mnt->mnt.data = sb->s_op->clone_mnt_data(old->mnt.data);
+ if (!mnt->mnt.data) {
+ goto out_free;
+ }
+ }
+
if (flag & (CL_SLAVE | CL_PRIVATE))
mnt->mnt_group_id = 0; /* not a peer of original */
else
@@ -774,6 +792,7 @@
return mnt;
out_free:
+ kfree(mnt->mnt.data);
free_vfsmnt(mnt);
return ERR_PTR(err);
}
@@ -1711,8 +1730,12 @@
down_write(&sb->s_umount);
if (flags & MS_BIND)
err = change_mount_flags(path->mnt, flags);
- else
+ else {
err = do_remount_sb(sb, flags, data, 0);
+ br_write_lock(&vfsmount_lock);
+ propagate_remount(mnt);
+ br_write_unlock(&vfsmount_lock);
+ }
if (!err) {
br_write_lock(&vfsmount_lock);
mnt_flags |= mnt->mnt.mnt_flags & ~MNT_USER_SETTABLE_MASK;
diff --git a/fs/pnode.c b/fs/pnode.c
index 61f3d51..c1148ba 100644
--- a/fs/pnode.c
+++ b/fs/pnode.c
@@ -356,3 +356,17 @@
__propagate_umount(mnt);
return 0;
}
+
+int propagate_remount(struct mount *mnt) {
+ struct mount *m;
+ struct super_block *sb = mnt->mnt.mnt_sb;
+ int ret = 0;
+
+ if (sb->s_op->copy_mnt_data) {
+ for (m = first_slave(mnt); m->mnt_slave.next != &mnt->mnt_slave_list; m = next_slave(m)) {
+ sb->s_op->copy_mnt_data(m->mnt.data, mnt->mnt.data);
+ }
+ }
+
+ return ret;
+}
diff --git a/fs/pnode.h b/fs/pnode.h
index 3471ddf..7bcd512 100644
--- a/fs/pnode.h
+++ b/fs/pnode.h
@@ -35,6 +35,7 @@
struct list_head *);
int propagate_umount(struct list_head *);
int propagate_mount_busy(struct mount *, int);
+int propagate_remount(struct mount *);
void mnt_release_group_id(struct mount *);
int get_dominating_id(struct mount *mnt, const struct path *root);
unsigned int mnt_get_count(struct mount *mnt);