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ANDROID: mnt: Add filesystem private data to mount points

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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>
This commit is contained in:
Daniel Rosenberg
2016-10-26 15:29:51 -07:00
committed by Dmitry Shmidt
parent 948041536c
commit 1aaf05b350
5 changed files with 46 additions and 1 deletions
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fs/namespace.c
+27 -1
View File
@@ -580,6 +580,7 @@ int sb_prepare_remount_readonly(struct super_block *sb)
static void free_vfsmnt(struct mount *mnt)
{
kfree(mnt->mnt.data);
kfree_const(mnt->mnt_devname);
#ifdef CONFIG_SMP
free_percpu(mnt->mnt_pcp);
@@ -948,11 +949,21 @@ vfs_kern_mount(struct file_system_type *type, int flags, const char *name, void
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);
mnt_free_id(mnt);
free_vfsmnt(mnt);
return ERR_CAST(root);
@@ -980,6 +991,14 @@ static struct mount *clone_mnt(struct mount *old, struct dentry *root,
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) {
err = -ENOMEM;
goto out_free;
}
}
if (flag & (CL_SLAVE | CL_PRIVATE | CL_SHARED_TO_SLAVE))
mnt->mnt_group_id = 0; /* not a peer of original */
else
@@ -1048,6 +1067,7 @@ static struct mount *clone_mnt(struct mount *old, struct dentry *root,
return mnt;
out_free:
kfree(mnt->mnt.data);
mnt_free_id(mnt);
free_vfsmnt(mnt);
return ERR_PTR(err);
@@ -2253,8 +2273,14 @@ static int do_remount(struct path *path, int flags, int mnt_flags,
err = change_mount_flags(path->mnt, flags);
else if (!capable(CAP_SYS_ADMIN))
err = -EPERM;
else
else {
err = do_remount_sb(sb, flags, data, 0);
namespace_lock();
lock_mount_hash();
propagate_remount(mnt);
unlock_mount_hash();
namespace_unlock();
}
if (!err) {
lock_mount_hash();
mnt_flags |= mnt->mnt.mnt_flags & ~MNT_USER_SETTABLE_MASK;