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SubjectRe: [PATCH 03/14] VFS: Implement a filesystem superblock creation/configuration context [ver #6]
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On 10/06/17 08:49, David Howells wrote:
>
> diff --git a/fs/fs_context.c b/fs/fs_context.c
> new file mode 100644
> index 000000000000..a3a7ccb4323d
> --- /dev/null
> +++ b/fs/fs_context.c

> +/**
> + * generic_parse_monolithic - Parse key[=val][,key[=val]]* mount data
> + * @mc: The superblock configuration to fill in.

function argument is &struct fs_context *ctx, not @mc

> + * @data: The data to parse
> + *
> + * Parse a blob of data that's in key[=val][,key[=val]]* form. This can be
> + * called from the ->monolithic_mount_data() fs_context operation.
> + *
> + * Returns 0 on success or the error returned by the ->parse_option() fs_context
> + * operation on failure.
> + */
> +int generic_parse_monolithic(struct fs_context *ctx, void *data)
> +{
> + char *options = data, *p;
> + int ret;
> +
> + if (!options)
> + return 0;
> +
> + while ((p = strsep(&options, ",")) != NULL) {
> + if (*p) {
> + ret = vfs_parse_mount_option(ctx, p);
> + if (ret < 0)
> + return ret;
> + }
> + }
> +
> + return 0;
> +}
> +EXPORT_SYMBOL(generic_parse_monolithic);
> +

> +
> +/**
> + * put_fs_context - Dispose of a superblock configuration context.
> + * @sc: The context to dispose of.

@fc:

> + */
> +void put_fs_context(struct fs_context *fc)
> +{
> + struct super_block *sb;
> +
> + if (fc->root) {
> + sb = fc->root->d_sb;
> + dput(fc->root);
> + fc->root = NULL;
> + deactivate_super(sb);
> + }
> +
> + if (fc->ops && fc->ops->free)
> + fc->ops->free(fc);
> +
> + security_fs_context_free(fc);
> + if (fc->net_ns)
> + put_net(fc->net_ns);
> + put_user_ns(fc->user_ns);
> + if (fc->cred)
> + put_cred(fc->cred);
> + kfree(fc->subtype);
> + put_filesystem(fc->fs_type);
> + kfree(fc->source);
> + kfree(fc);
> +}
> +EXPORT_SYMBOL(put_fs_context);


(in fs/namespace.c:)

> +/**
> + * vfs_create_mount - Create a mount for a configured superblock
> + * fc: The configuration context with the superblock attached

@fc:

> + *
> + * Create a mount to an already configured superblock. If necessary, the
> + * caller should invoke vfs_get_tree() before calling this.
> + *
> + * Note that this does not attach the mount to anything.
> + */
> +struct vfsmount *vfs_create_mount(struct fs_context *fc)
> +{
> + struct mount *mnt;
> +
> + if (!fc->root)
> + return ERR_PTR(-EINVAL);
> +
> + mnt = alloc_vfsmnt(fc->source ?: "none");
> + if (!mnt)
> + return ERR_PTR(-ENOMEM);
> +
> + if (fc->purpose == FS_CONTEXT_FOR_KERNEL_MOUNT)
> + /* It's a longterm mount, don't release mnt until we unmount
> + * before file sys is unregistered
> + */
> + mnt->mnt.mnt_flags = MNT_INTERNAL;
> +
> + atomic_inc(&fc->root->d_sb->s_active);
> + mnt->mnt.mnt_sb = fc->root->d_sb;
> + mnt->mnt.mnt_root = dget(fc->root);
> + mnt->mnt_mountpoint = mnt->mnt.mnt_root;
> + mnt->mnt_parent = mnt;
> +
> + lock_mount_hash();
> + list_add_tail(&mnt->mnt_instance, &mnt->mnt.mnt_sb->s_mounts);
> + unlock_mount_hash();
> + return &mnt->mnt;
> +}
> +EXPORT_SYMBOL(vfs_create_mount);


--
~Randy

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