Commit 1866d779 authored by Max Reitz's avatar Max Reitz Committed by Miklos Szeredi
Browse files

fuse: Allow fuse_fill_super_common() for submounts 



Submounts have their own superblock, which needs to be initialized.
However, they do not have a fuse_fs_context associated with them, and
the root node's attributes should be taken from the mountpoint's node.

Extend fuse_fill_super_common() to work for submounts by making the @ctx
parameter optional, and by adding a @submount_finode parameter.

(There is a plain "unsigned" in an existing code block that is being
indented by this commit.  Extend it to "unsigned int" so checkpatch does
not complain.)

Signed-off-by: default avatarMax Reitz <mreitz@redhat.com>
Signed-off-by: default avatarMiklos Szeredi <mszeredi@redhat.com>
parent fcee216b

fs/fuse/fuse_i.h

+8 −0
Original line number Diff line number Diff line
@@ -1044,6 +1044,14 @@ void fuse_send_init(struct fuse_mount *fm); 
 */

int fuse_fill_super_common(struct super_block *sb, struct fuse_fs_context *ctx);



/*

 * Fill in superblock for submounts

 * @sb: partially-initialized superblock to fill in

 * @parent_fi: The fuse_inode of the parent filesystem where this submount is

 * 	       mounted

 */

int fuse_fill_super_submount(struct super_block *sb,

			     struct fuse_inode *parent_fi);



/*

 * Remove the mount from the connection

fs/fuse/inode.c

+88 −21
Original line number Diff line number Diff line
@@ -126,9 +126,12 @@ static void fuse_evict_inode(struct inode *inode) 


		if (FUSE_IS_DAX(inode))

			fuse_dax_inode_cleanup(inode);

		fuse_queue_forget(fc, fi->forget, fi->nodeid, fi->nlookup);

		if (fi->nlookup) {

			fuse_queue_forget(fc, fi->forget, fi->nodeid,

					  fi->nlookup);

			fi->forget = NULL;

		}

	}

	if (S_ISREG(inode->i_mode) && !is_bad_inode(inode)) {

		WARN_ON(!list_empty(&fi->write_files));

		WARN_ON(!list_empty(&fi->queued_writes));
@@ -1207,6 +1210,87 @@ void fuse_dev_free(struct fuse_dev *fud) 
}

EXPORT_SYMBOL_GPL(fuse_dev_free);



static void fuse_fill_attr_from_inode(struct fuse_attr *attr,

				      const struct fuse_inode *fi)

{

	*attr = (struct fuse_attr){

		.ino		= fi->inode.i_ino,

		.size		= fi->inode.i_size,

		.blocks		= fi->inode.i_blocks,

		.atime		= fi->inode.i_atime.tv_sec,

		.mtime		= fi->inode.i_mtime.tv_sec,

		.ctime		= fi->inode.i_ctime.tv_sec,

		.atimensec	= fi->inode.i_atime.tv_nsec,

		.mtimensec	= fi->inode.i_mtime.tv_nsec,

		.ctimensec	= fi->inode.i_ctime.tv_nsec,

		.mode		= fi->inode.i_mode,

		.nlink		= fi->inode.i_nlink,

		.uid		= fi->inode.i_uid.val,

		.gid		= fi->inode.i_gid.val,

		.rdev		= fi->inode.i_rdev,

		.blksize	= 1u << fi->inode.i_blkbits,

	};

}



static void fuse_sb_defaults(struct super_block *sb)

{

	sb->s_magic = FUSE_SUPER_MAGIC;

	sb->s_op = &fuse_super_operations;

	sb->s_xattr = fuse_xattr_handlers;

	sb->s_maxbytes = MAX_LFS_FILESIZE;

	sb->s_time_gran = 1;

	sb->s_export_op = &fuse_export_operations;

	sb->s_iflags |= SB_I_IMA_UNVERIFIABLE_SIGNATURE;

	if (sb->s_user_ns != &init_user_ns)

		sb->s_iflags |= SB_I_UNTRUSTED_MOUNTER;

	sb->s_flags &= ~(SB_NOSEC | SB_I_VERSION);



	/*

	 * If we are not in the initial user namespace posix

	 * acls must be translated.

	 */

	if (sb->s_user_ns != &init_user_ns)

		sb->s_xattr = fuse_no_acl_xattr_handlers;

}



int fuse_fill_super_submount(struct super_block *sb,

			     struct fuse_inode *parent_fi)

{

	struct fuse_mount *fm = get_fuse_mount_super(sb);

	struct super_block *parent_sb = parent_fi->inode.i_sb;

	struct fuse_attr root_attr;

	struct inode *root;



	fuse_sb_defaults(sb);

	fm->sb = sb;



	WARN_ON(sb->s_bdi != &noop_backing_dev_info);

	sb->s_bdi = bdi_get(parent_sb->s_bdi);



	sb->s_xattr = parent_sb->s_xattr;

	sb->s_time_gran = parent_sb->s_time_gran;

	sb->s_blocksize = parent_sb->s_blocksize;

	sb->s_blocksize_bits = parent_sb->s_blocksize_bits;

	sb->s_subtype = kstrdup(parent_sb->s_subtype, GFP_KERNEL);

	if (parent_sb->s_subtype && !sb->s_subtype)

		return -ENOMEM;



	fuse_fill_attr_from_inode(&root_attr, parent_fi);

	root = fuse_iget(sb, parent_fi->nodeid, 0, &root_attr, 0, 0);

	/*

	 * This inode is just a duplicate, so it is not looked up and

	 * its nlookup should not be incremented.  fuse_iget() does

	 * that, though, so undo it here.

	 */

	get_fuse_inode(root)->nlookup--;

	sb->s_d_op = &fuse_dentry_operations;

	sb->s_root = d_make_root(root);

	if (!sb->s_root)

		return -ENOMEM;



	return 0;

}



int fuse_fill_super_common(struct super_block *sb, struct fuse_fs_context *ctx)

{

	struct fuse_dev *fud = NULL;
@@ -1220,7 +1304,7 @@ int fuse_fill_super_common(struct super_block *sb, struct fuse_fs_context *ctx) 
	if (sb->s_flags & SB_MANDLOCK)

		goto err;



	sb->s_flags &= ~(SB_NOSEC | SB_I_VERSION);

	fuse_sb_defaults(sb);



	if (ctx->is_bdev) {

#ifdef CONFIG_BLOCK
@@ -1235,23 +1319,6 @@ int fuse_fill_super_common(struct super_block *sb, struct fuse_fs_context *ctx) 


	sb->s_subtype = ctx->subtype;

	ctx->subtype = NULL;

	sb->s_magic = FUSE_SUPER_MAGIC;

	sb->s_op = &fuse_super_operations;

	sb->s_xattr = fuse_xattr_handlers;

	sb->s_maxbytes = MAX_LFS_FILESIZE;

	sb->s_time_gran = 1;

	sb->s_export_op = &fuse_export_operations;

	sb->s_iflags |= SB_I_IMA_UNVERIFIABLE_SIGNATURE;

	if (sb->s_user_ns != &init_user_ns)

		sb->s_iflags |= SB_I_UNTRUSTED_MOUNTER;



	/*

	 * If we are not in the initial user namespace posix

	 * acls must be translated.

	 */

	if (sb->s_user_ns != &init_user_ns)

		sb->s_xattr = fuse_no_acl_xattr_handlers;



	if (IS_ENABLED(CONFIG_FUSE_DAX)) {

		err = fuse_dax_conn_alloc(fc, ctx->dax_dev);

		if (err)
@@ -1281,7 +1348,7 @@ int fuse_fill_super_common(struct super_block *sb, struct fuse_fs_context *ctx) 
	fc->user_id = ctx->user_id;

	fc->group_id = ctx->group_id;

	fc->legacy_opts_show = ctx->legacy_opts_show;

	fc->max_read = max_t(unsigned, 4096, ctx->max_read);

	fc->max_read = max_t(unsigned int, 4096, ctx->max_read);

	fc->destroy = ctx->destroy;

	fc->no_control = ctx->no_control;

	fc->no_force_umount = ctx->no_force_umount;

CRA Git | Maintained and supported by SUSTech CRA and CCSE