Commit 0cc2656c authored by Stefan Hajnoczi's avatar Stefan Hajnoczi Committed by Miklos Szeredi
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fuse: extract fuse_fill_super_common() 



fuse_fill_super() includes code to process the fd= option and link the
struct fuse_dev to the fd's struct file.  In virtio-fs there is no file
descriptor because /dev/fuse is not used.

This patch extracts fuse_fill_super_common() so that both classic fuse and
virtio-fs can share the code to initialize a mount.

Signed-off-by: default avatarStefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: default avatarMiklos Szeredi <mszeredi@redhat.com>
parent 4388c5aa

fs/fuse/fuse_i.h

+27 −0
Original line number Diff line number Diff line
@@ -416,6 +416,26 @@ struct fuse_dev { 
	struct list_head entry;

};



struct fuse_fs_context {

	int fd;

	unsigned int rootmode;

	kuid_t user_id;

	kgid_t group_id;

	bool is_bdev:1;

	bool fd_present:1;

	bool rootmode_present:1;

	bool user_id_present:1;

	bool group_id_present:1;

	bool default_permissions:1;

	bool allow_other:1;

	unsigned int max_read;

	unsigned int blksize;

	const char *subtype;



	/* fuse_dev pointer to fill in, should contain NULL on entry */

	void **fudptr;

};



/**

 * A Fuse connection.

 *
@@ -873,6 +893,13 @@ struct fuse_dev *fuse_dev_alloc(struct fuse_conn *fc); 
void fuse_dev_free(struct fuse_dev *fud);

void fuse_send_init(struct fuse_conn *fc);



/**

 * Fill in superblock and initialize fuse connection

 * @sb: partially-initialized superblock to fill in

 * @ctx: mount context

 */

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



/**

 * Add connection to control filesystem

 */

fs/fuse/inode.c

+53 −59
Original line number Diff line number Diff line
@@ -64,23 +64,6 @@ MODULE_PARM_DESC(max_user_congthresh, 
static struct file_system_type fuseblk_fs_type;

#endif



struct fuse_fs_context {

	const char	*subtype;

	bool		is_bdev;

	int fd;

	unsigned rootmode;

	kuid_t user_id;

	kgid_t group_id;

	unsigned fd_present:1;

	unsigned rootmode_present:1;

	unsigned user_id_present:1;

	unsigned group_id_present:1;

	unsigned default_permissions:1;

	unsigned allow_other:1;

	unsigned max_read;

	unsigned blksize;

};



struct fuse_forget_link *fuse_alloc_forget(void)

{

	return kzalloc(sizeof(struct fuse_forget_link), GFP_KERNEL);
@@ -1100,16 +1083,13 @@ void fuse_dev_free(struct fuse_dev *fud) 
}

EXPORT_SYMBOL_GPL(fuse_dev_free);



static int fuse_fill_super(struct super_block *sb, struct fs_context *fsc)

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

{

	struct fuse_fs_context *ctx = fsc->fs_private;

	struct fuse_dev *fud;

	struct fuse_conn *fc;

	struct fuse_conn *fc = get_fuse_conn_super(sb);

	struct inode *root;

	struct file *file;

	struct dentry *root_dentry;

	int err;

	int is_bdev = sb->s_bdev != NULL;



	err = -EINVAL;

	if (sb->s_flags & SB_MANDLOCK)
@@ -1117,7 +1097,7 @@ static int fuse_fill_super(struct super_block *sb, struct fs_context *fsc) 


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



	if (is_bdev) {

	if (ctx->is_bdev) {

#ifdef CONFIG_BLOCK

		err = -EINVAL;

		if (!sb_set_blocksize(sb, ctx->blksize))
@@ -1140,19 +1120,6 @@ static int fuse_fill_super(struct super_block *sb, struct fs_context *fsc) 
	if (sb->s_user_ns != &init_user_ns)

		sb->s_iflags |= SB_I_UNTRUSTED_MOUNTER;



	file = fget(ctx->fd);

	err = -EINVAL;

	if (!file)

		goto err;



	/*

	 * Require mount to happen from the same user namespace which

	 * opened /dev/fuse to prevent potential attacks.

	 */

	if (file->f_op != &fuse_dev_operations ||

	    file->f_cred->user_ns != sb->s_user_ns)

		goto err_fput;



	/*

	 * If we are not in the initial user namespace posix

	 * acls must be translated.
@@ -1160,17 +1127,9 @@ static int fuse_fill_super(struct super_block *sb, struct fs_context *fsc) 
	if (sb->s_user_ns != &init_user_ns)

		sb->s_xattr = fuse_no_acl_xattr_handlers;



	fc = kmalloc(sizeof(*fc), GFP_KERNEL);

	err = -ENOMEM;

	if (!fc)

		goto err_fput;



	fuse_conn_init(fc, sb->s_user_ns);

	fc->release = fuse_free_conn;



	fud = fuse_dev_alloc(fc);

	if (!fud)

		goto err_put_conn;

		goto err;



	fc->dev = sb->s_dev;

	fc->sb = sb;
@@ -1188,10 +1147,7 @@ static int fuse_fill_super(struct super_block *sb, struct fs_context *fsc) 
	fc->user_id = ctx->user_id;

	fc->group_id = ctx->group_id;

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

	fc->destroy = is_bdev;



	/* Used by get_root_inode() */

	sb->s_fs_info = fc;

	fc->destroy = ctx->is_bdev;



	err = -ENOMEM;

	root = fuse_get_root_inode(sb, ctx->rootmode);
@@ -1204,7 +1160,7 @@ static int fuse_fill_super(struct super_block *sb, struct fs_context *fsc) 


	mutex_lock(&fuse_mutex);

	err = -EINVAL;

	if (file->private_data)

	if (*ctx->fudptr)

		goto err_unlock;



	err = fuse_ctl_add_conn(fc);
@@ -1213,24 +1169,62 @@ static int fuse_fill_super(struct super_block *sb, struct fs_context *fsc) 


	list_add_tail(&fc->entry, &fuse_conn_list);

	sb->s_root = root_dentry;

	file->private_data = fud;

	*ctx->fudptr = fud;

	mutex_unlock(&fuse_mutex);

	return 0;



 err_unlock:

	mutex_unlock(&fuse_mutex);

	dput(root_dentry);

 err_dev_free:

	fuse_dev_free(fud);

 err:

	return err;

}

EXPORT_SYMBOL_GPL(fuse_fill_super_common);



static int fuse_fill_super(struct super_block *sb, struct fs_context *fsc)

{

	struct fuse_fs_context *ctx = fsc->fs_private;

	struct file *file;

	int err;

	struct fuse_conn *fc;



	err = -EINVAL;

	file = fget(ctx->fd);

	if (!file)

		goto err;



	/*

	 * Require mount to happen from the same user namespace which

	 * opened /dev/fuse to prevent potential attacks.

	 */

	if ((file->f_op != &fuse_dev_operations) ||

	    (file->f_cred->user_ns != sb->s_user_ns))

		goto err_fput;

	ctx->fudptr = &file->private_data;



	fc = kmalloc(sizeof(*fc), GFP_KERNEL);

	err = -ENOMEM;

	if (!fc)

		goto err_fput;



	fuse_conn_init(fc, sb->s_user_ns);

	fc->release = fuse_free_conn;

	sb->s_fs_info = fc;



	err = fuse_fill_super_common(sb, ctx);

	if (err)

		goto err_put_conn;

	/*

	 * atomic_dec_and_test() in fput() provides the necessary

	 * memory barrier for file->private_data to be visible on all

	 * CPUs after this

	 */

	fput(file);



	fuse_send_init(fc);



	fuse_send_init(get_fuse_conn_super(sb));

	return 0;



 err_unlock:

	mutex_unlock(&fuse_mutex);

	dput(root_dentry);

 err_dev_free:

	fuse_dev_free(fud);

 err_put_conn:

	fuse_conn_put(fc);

	sb->s_fs_info = NULL;

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