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: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
This commit is contained in:
Stefan Hajnoczi 2018-06-13 10:23:04 +01:00 committed by Miklos Szeredi
parent 4388c5aac4
commit 0cc2656cdb
2 changed files with 81 additions and 60 deletions

View File

@ -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
*/

View File

@ -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);
@ -1213,17 +1169,8 @@ 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);
/*
* 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);
return 0;
err_unlock:
@ -1231,6 +1178,53 @@ static int fuse_fill_super(struct super_block *sb, struct fs_context *fsc)
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(get_fuse_conn_super(sb));
return 0;
err_put_conn:
fuse_conn_put(fc);
sb->s_fs_info = NULL;