diff options
| -rw-r--r-- | src/kernel/xloop_main_6.6.c | 2160 | ||||
| -rw-r--r-- | src/kernel/xloop_main_6.6.h | 98 |
2 files changed, 2258 insertions, 0 deletions
diff --git a/src/kernel/xloop_main_6.6.c b/src/kernel/xloop_main_6.6.c new file mode 100644 index 0000000..b964ec4 --- /dev/null +++ b/src/kernel/xloop_main_6.6.c @@ -0,0 +1,2160 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * xloop_main.c + * + * Written by Theodore Ts'o, 3/29/93 + */ + +#include <linux/module.h> +#include <linux/moduleparam.h> +#include <linux/sched.h> +#include <linux/fs.h> +#include <linux/pagemap.h> +#include <linux/file.h> +#include <linux/stat.h> +#include <linux/errno.h> +#include <linux/major.h> +#include <linux/wait.h> +#include <linux/blkpg.h> +#include <linux/init.h> +#include <linux/swap.h> +#include <linux/slab.h> +#include <linux/compat.h> +#include <linux/suspend.h> +#include <linux/freezer.h> +#include <linux/mutex.h> +#include <linux/writeback.h> +#include <linux/completion.h> +#include <linux/highmem.h> +#include <linux/splice.h> +#include <linux/sysfs.h> +#include <linux/miscdevice.h> +#include <linux/falloc.h> +#include <linux/uio.h> +#include <linux/ioprio.h> +#include <linux/blk-cgroup.h> +#include <linux/sched/mm.h> +#include <linux/statfs.h> +#include <linux/uaccess.h> +//#include <linux/blk-mq.h> +//#include <linux/spinlock.h> + +#include <linux/version.h> +#ifdef CONFIG_DEBUG_FS +#include <linux/debugfs.h> +#endif + +#include <xloop/version.h> + +#include "xloop_file_fmt.h" +#include "xloop_main.h" + +#define XLOOP_IDLE_WORKER_TIMEOUT (60 * HZ) +#define XLOOP_DEFAULT_HW_Q_DEPTH 128 + +static DEFINE_IDR(xloop_index_idr); +static DEFINE_MUTEX(xloop_ctl_mutex); +static DEFINE_MUTEX(xloop_validate_mutex); + +/** + * xloop_global_lock_killable() - take locks for safe xloop_validate_file() test + * + * @xlo: struct xloop_device + * @global: true if @xlo is about to bind another "struct xloop_device", false otherwise + * + * Returns 0 on success, -EINTR otherwise. + * + * Since xloop_validate_file() traverses on other "struct xloop_device" if + * is_xloop_device() is true, we need a global lock for serializing concurrent + * xloop_configure()/xloop_change_fd()/__xloop_clr_fd() calls. + */ +static int xloop_global_lock_killable(struct xloop_device *xlo, bool global) +{ + int err; + + if (global) { + err = mutex_lock_killable(&xloop_validate_mutex); + if (err) + return err; + } + err = mutex_lock_killable(&xlo->xlo_mutex); + if (err && global) + mutex_unlock(&xloop_validate_mutex); + return err; +} + +/** + * xloop_global_unlock() - release locks taken by xloop_global_lock_killable() + * + * @xlo: struct xloop_device + * @global: true if @xlo was about to bind another "struct xloop_device", false otherwise + */ +static void xloop_global_unlock(struct xloop_device *xlo, bool global) +{ + mutex_unlock(&xlo->xlo_mutex); + if (global) + mutex_unlock(&xloop_validate_mutex); +} + +static int max_part; +static int part_shift; + +struct device *xloop_device_to_dev(struct xloop_device *xlo) +{ + return disk_to_dev(xlo->xlo_disk); +} +EXPORT_SYMBOL(xloop_device_to_dev); + +static loff_t get_xloop_size(struct xloop_device *xlo, struct file *file) +{ + return xloop_file_fmt_sector_size(xlo->xlo_fmt, file, xlo->xlo_offset, xlo->xlo_sizelimit); +} + +static void __xloop_update_dio(struct xloop_device *xlo, bool dio) +{ + struct file *file = xlo->xlo_backing_file; + struct address_space *mapping = file->f_mapping; + struct inode *inode = mapping->host; + unsigned short sb_bsize = 0; + unsigned dio_align = 0; + bool use_dio; + + if (inode->i_sb->s_bdev) { + sb_bsize = bdev_logical_block_size(inode->i_sb->s_bdev); + dio_align = sb_bsize - 1; + } + + /* + * We support direct I/O only if xlo_offset is aligned with the + * logical I/O size of backing device, and the logical block + * size of xloop is bigger than the backing device's. + * + * TODO: the above condition may be loosed in the future, and + * direct I/O may be switched runtime at that time because most + * of requests in sane applications should be PAGE_SIZE aligned + */ + if (dio) { + if (queue_logical_block_size(xlo->xlo_queue) >= sb_bsize && + !(xlo->xlo_offset & dio_align) && + (file->f_mode & FMODE_CAN_ODIRECT)) + use_dio = true; + else + use_dio = false; + } else { + use_dio = false; + } + + if (xlo->use_dio == use_dio) + return; + + /* flush dirty pages before changing direct IO */ + xloop_file_fmt_flush(xlo->xlo_fmt); + + /* + * The flag of XLO_FLAGS_DIRECT_IO is handled similarly with + * XLO_FLAGS_READ_ONLY, both are set from kernel, and xlosetup + * will get updated by ioctl(XLOOP_GET_STATUS) + */ + if (xlo->xlo_state == Xlo_bound) + blk_mq_freeze_queue(xlo->xlo_queue); + xlo->use_dio = use_dio; + if (use_dio) { + blk_queue_flag_clear(QUEUE_FLAG_NOMERGES, xlo->xlo_queue); + xlo->xlo_flags |= XLO_FLAGS_DIRECT_IO; + } else { + blk_queue_flag_set(QUEUE_FLAG_NOMERGES, xlo->xlo_queue); + xlo->xlo_flags &= ~XLO_FLAGS_DIRECT_IO; + } + if (xlo->xlo_state == Xlo_bound) + blk_mq_unfreeze_queue(xlo->xlo_queue); +} + +/** + * xloop_set_size() - sets device size and notifies userspace + * @xlo: struct xloop_device to set the size for + * @size: new size of the xloop device + * + * Callers must validate that the size passed into this function fits into + * a sector_t, eg using xloop_validate_size() + */ +static void xloop_set_size(struct xloop_device *xlo, loff_t size) +{ + if (!set_capacity_and_notify(xlo->xlo_disk, size)) + kobject_uevent(&disk_to_dev(xlo->xlo_disk)->kobj, KOBJ_CHANGE); +} + +static void xlo_complete_rq(struct request *rq) +{ + struct xloop_cmd *cmd = blk_mq_rq_to_pdu(rq); + blk_status_t ret = BLK_STS_OK; + + if (!cmd->use_aio || cmd->ret < 0 || cmd->ret == blk_rq_bytes(rq) || + req_op(rq) != REQ_OP_READ) { + if (cmd->ret < 0) + ret = errno_to_blk_status(cmd->ret); + goto end_io; + } + + /* + * Short READ - if we got some data, advance our request and + * retry it. If we got no data, end the rest with EIO. + */ + if (cmd->ret) { + blk_update_request(rq, BLK_STS_OK, cmd->ret); + cmd->ret = 0; + blk_mq_requeue_request(rq, true); + } else { + if (cmd->use_aio) { + struct bio *bio = rq->bio; + + while (bio) { + zero_fill_bio(bio); + bio = bio->bi_next; + } + } + ret = BLK_STS_IOERR; +end_io: + blk_mq_end_request(rq, ret); + } +} + +static int do_req_filebacked(struct xloop_device *xlo, struct request *rq) +{ + struct xloop_cmd *cmd = blk_mq_rq_to_pdu(rq); + + /* + * xlo_write_simple and xlo_read_simple should have been covered + * by io submit style function like xloop_file_fmt_read_aio(), one + * blocker is that xloop_file_fmt_read() need to call flush_dcache_page + * after the page is written from kernel, and it isn't easy to handle + * this in io submit style function which submits all segments + * of the req at one time. And direct read IO doesn't need to + * run flush_dcache_page(). + */ + switch (req_op(rq)) { + case REQ_OP_FLUSH: + return xloop_file_fmt_flush(xlo->xlo_fmt); + case REQ_OP_WRITE_ZEROES: + return xloop_file_fmt_write_zeros(xlo->xlo_fmt, rq); + case REQ_OP_DISCARD: + return xloop_file_fmt_discard(xlo->xlo_fmt, rq); + case REQ_OP_WRITE: + if (cmd->use_aio) + return xloop_file_fmt_write_aio(xlo->xlo_fmt, rq); + else + return xloop_file_fmt_write(xlo->xlo_fmt, rq); + case REQ_OP_READ: + if (cmd->use_aio) + return xloop_file_fmt_read_aio(xlo->xlo_fmt, rq); + else + return xloop_file_fmt_read(xlo->xlo_fmt, rq); + default: + WARN_ON_ONCE(1); + return -EIO; + } +} + +static inline void xloop_update_dio(struct xloop_device *xlo) +{ + __xloop_update_dio(xlo, (xlo->xlo_backing_file->f_flags & O_DIRECT) | + xlo->use_dio); +} + +static void xloop_reread_partitions(struct xloop_device *xlo) +{ + int rc; + + mutex_lock(&xlo->xlo_disk->open_mutex); + rc = bdev_disk_changed(xlo->xlo_disk, false); + mutex_unlock(&xlo->xlo_disk->open_mutex); + if (rc) + dev_warn(xloop_device_to_dev(xlo), + "partition scan of xloop%d (%s) failed (rc=%d)\n", + xlo->xlo_number, xlo->xlo_file_name, rc); +} + +static inline int is_xloop_device(struct file *file) +{ + struct inode *i = file->f_mapping->host; + + return i && S_ISBLK(i->i_mode) && imajor(i) == XLOOP_MAJOR; +} + +static int xloop_validate_file(struct file *file, struct block_device *bdev) +{ + struct inode *inode = file->f_mapping->host; + struct file *f = file; + + /* Avoid recursion */ + while (is_xloop_device(f)) { + struct xloop_device *l; + + lockdep_assert_held(&xloop_validate_mutex); + if (f->f_mapping->host->i_rdev == bdev->bd_dev) + return -EBADF; + + l = I_BDEV(f->f_mapping->host)->bd_disk->private_data; + if (l->xlo_state != Xlo_bound) + return -EINVAL; + /* Order wrt setting xlo->xlo_backing_file in xloop_configure(). */ + rmb(); + f = l->xlo_backing_file; + } + if (!S_ISREG(inode->i_mode) && !S_ISBLK(inode->i_mode)) + return -EINVAL; + return 0; +} + +/* + * xloop_change_fd switched the backing store of a xloopback device to + * a new file. This is useful for operating system installers to free up + * the original file and in High Availability environments to switch to + * an alternative location for the content in case of server meltdown. + * This can only work if the xloop device is used read-only, and if the + * new backing store is the same size and type as the old backing store. + */ +static int xloop_change_fd(struct xloop_device *xlo, struct block_device *bdev, + unsigned int arg) +{ + struct file *file = fget(arg); + struct file *old_file; + int error; + bool partscan; + bool is_xloop; + + if (!file) + return -EBADF; + + /* suppress uevents while reconfiguring the device */ + dev_set_uevent_suppress(disk_to_dev(xlo->xlo_disk), 1); + + is_xloop = is_xloop_device(file); + error = xloop_global_lock_killable(xlo, is_xloop); + if (error) + goto out_putf; + error = -ENXIO; + if (xlo->xlo_state != Xlo_bound) + goto out_err; + + /* the xloop device has to be read-only */ + error = -EINVAL; + if (!(xlo->xlo_flags & XLO_FLAGS_READ_ONLY)) + goto out_err; + + error = xloop_validate_file(file, bdev); + if (error) + goto out_err; + + old_file = xlo->xlo_backing_file; + + error = -EINVAL; + + /* size of the new backing store needs to be the same */ + if (get_xloop_size(xlo, file) != get_xloop_size(xlo, old_file)) + goto out_err; + + /* and ... switch */ + disk_force_media_change(xlo->xlo_disk); + blk_mq_freeze_queue(xlo->xlo_queue); + mapping_set_gfp_mask(old_file->f_mapping, xlo->old_gfp_mask); + xlo->xlo_backing_file = file; + xlo->old_gfp_mask = mapping_gfp_mask(file->f_mapping); + mapping_set_gfp_mask(file->f_mapping, + xlo->old_gfp_mask & ~(__GFP_IO|__GFP_FS)); + xloop_update_dio(xlo); + blk_mq_unfreeze_queue(xlo->xlo_queue); + partscan = xlo->xlo_flags & XLO_FLAGS_PARTSCAN; + xloop_global_unlock(xlo, is_xloop); + + /* + * Flush xloop_validate_file() before fput(), for l->xlo_backing_file + * might be pointing at old_file which might be the last reference. + */ + if (!is_xloop) { + mutex_lock(&xloop_validate_mutex); + mutex_unlock(&xloop_validate_mutex); + } + /* + * We must drop file reference outside of xlo_mutex as dropping + * the file ref can take open_mutex which creates circular locking + * dependency. + */ + fput(old_file); + if (partscan) + xloop_reread_partitions(xlo); + + error = 0; +done: + /* enable and uncork uevent now that we are done */ + dev_set_uevent_suppress(disk_to_dev(xlo->xlo_disk), 0); + return error; + +out_err: + xloop_global_unlock(xlo, is_xloop); +out_putf: + fput(file); + goto done; +} + +/* xloop sysfs attributes */ + +static ssize_t xloop_attr_show(struct device *dev, char *page, + ssize_t (*callback)(struct xloop_device *, char *)) +{ + struct gendisk *disk = dev_to_disk(dev); + struct xloop_device *xlo = disk->private_data; + + return callback(xlo, page); +} + +#define XLOOP_ATTR_RO(_name) \ +static ssize_t xloop_attr_##_name##_show(struct xloop_device *, char *); \ +static ssize_t xloop_attr_do_show_##_name(struct device *d, \ + struct device_attribute *attr, char *b) \ +{ \ + return xloop_attr_show(d, b, xloop_attr_##_name##_show); \ +} \ +static struct device_attribute xloop_attr_##_name = \ + __ATTR(_name, 0444, xloop_attr_do_show_##_name, NULL); + +static ssize_t xloop_attr_backing_file_show(struct xloop_device *xlo, char *buf) +{ + ssize_t ret; + char *p = NULL; + + spin_lock_irq(&xlo->xlo_lock); + if (xlo->xlo_backing_file) + p = file_path(xlo->xlo_backing_file, buf, PAGE_SIZE - 1); + spin_unlock_irq(&xlo->xlo_lock); + + if (IS_ERR_OR_NULL(p)) + ret = PTR_ERR(p); + else { + ret = strlen(p); + memmove(buf, p, ret); + buf[ret++] = '\n'; + buf[ret] = 0; + } + + return ret; +} + +static ssize_t xloop_attr_file_fmt_type_show(struct xloop_device *xlo, char *buf) +{ + ssize_t len = 0; + + len = xloop_file_fmt_print_type(xlo->xlo_fmt->file_fmt_type, buf); + len += sysfs_emit(buf + len, "\n"); + + return len; +} + +static ssize_t xloop_attr_offset_show(struct xloop_device *xlo, char *buf) +{ + return sysfs_emit(buf, "%llu\n", (unsigned long long)xlo->xlo_offset); +} + +static ssize_t xloop_attr_sizelimit_show(struct xloop_device *xlo, char *buf) +{ + return sysfs_emit(buf, "%llu\n", (unsigned long long)xlo->xlo_sizelimit); +} + +static ssize_t xloop_attr_autoclear_show(struct xloop_device *xlo, char *buf) +{ + int autoclear = (xlo->xlo_flags & XLO_FLAGS_AUTOCLEAR); + + return sysfs_emit(buf, "%s\n", autoclear ? "1" : "0"); +} + +static ssize_t xloop_attr_partscan_show(struct xloop_device *xlo, char *buf) +{ + int partscan = (xlo->xlo_flags & XLO_FLAGS_PARTSCAN); + + return sysfs_emit(buf, "%s\n", partscan ? "1" : "0"); +} + +static ssize_t xloop_attr_dio_show(struct xloop_device *xlo, char *buf) +{ + int dio = (xlo->xlo_flags & XLO_FLAGS_DIRECT_IO); + + return sysfs_emit(buf, "%s\n", dio ? "1" : "0"); +} + +XLOOP_ATTR_RO(backing_file); +XLOOP_ATTR_RO(file_fmt_type); +XLOOP_ATTR_RO(offset); +XLOOP_ATTR_RO(sizelimit); +XLOOP_ATTR_RO(autoclear); +XLOOP_ATTR_RO(partscan); +XLOOP_ATTR_RO(dio); + +static struct attribute *xloop_attrs[] = { + &xloop_attr_backing_file.attr, + &xloop_attr_file_fmt_type.attr, + &xloop_attr_offset.attr, + &xloop_attr_sizelimit.attr, + &xloop_attr_autoclear.attr, + &xloop_attr_partscan.attr, + &xloop_attr_dio.attr, + NULL, +}; + +static struct attribute_group xloop_attribute_group = { + .name = "xloop", + .attrs = xloop_attrs, +}; + +static void xloop_sysfs_init(struct xloop_device *xlo) +{ + xlo->sysfs_inited = !sysfs_create_group(&disk_to_dev(xlo->xlo_disk)->kobj, + &xloop_attribute_group); +} + +static void xloop_sysfs_exit(struct xloop_device *xlo) +{ + if (xlo->sysfs_inited) + sysfs_remove_group(&disk_to_dev(xlo->xlo_disk)->kobj, + &xloop_attribute_group); +} + +static void xloop_config_discard(struct xloop_device *xlo) +{ + struct file *file = xlo->xlo_backing_file; + struct inode *inode = file->f_mapping->host; + struct request_queue *q = xlo->xlo_queue; + u32 granularity, max_discard_sectors; + + /* + * If the backing device is a block device, mirror its zeroing + * capability. Set the discard sectors to the block device's zeroing + * capabilities because xloop discards result in blkdev_issue_zeroout(), + * not blkdev_issue_discard(). This maintains consistent behavior with + * file-backed xloop devices: discarded regions read back as zero. + */ + if (S_ISBLK(inode->i_mode)) { + struct request_queue *backingq = bdev_get_queue(I_BDEV(inode)); + + max_discard_sectors = backingq->limits.max_write_zeroes_sectors; + granularity = bdev_discard_granularity(I_BDEV(inode)) ?: + queue_physical_block_size(backingq); + + /* + * We use punch hole to reclaim the free space used by the + * image a.k.a. discard. + */ + } else if (!file->f_op->fallocate) { + max_discard_sectors = 0; + granularity = 0; + + } else { + struct kstatfs sbuf; + + max_discard_sectors = UINT_MAX >> 9; + if (!vfs_statfs(&file->f_path, &sbuf)) + granularity = sbuf.f_bsize; + else + max_discard_sectors = 0; + } + + if (max_discard_sectors) { + q->limits.discard_granularity = granularity; + blk_queue_max_discard_sectors(q, max_discard_sectors); + blk_queue_max_write_zeroes_sectors(q, max_discard_sectors); + } else { + q->limits.discard_granularity = 0; + blk_queue_max_discard_sectors(q, 0); + blk_queue_max_write_zeroes_sectors(q, 0); + } +} + +struct xloop_worker { + struct rb_node rb_node; + struct work_struct work; + struct list_head cmd_list; + struct list_head idle_list; + struct xloop_device *xlo; + struct cgroup_subsys_state *blkcg_css; + unsigned long last_ran_at; +}; + +static void xloop_workfn(struct work_struct *work); + +#ifdef CONFIG_BLK_CGROUP +static inline int queue_on_root_worker(struct cgroup_subsys_state *css) +{ + return !css || css == blkcg_root_css; +} +#else +static inline int queue_on_root_worker(struct cgroup_subsys_state *css) +{ + return !css; +} +#endif + +static void xloop_queue_work(struct xloop_device *xlo, struct xloop_cmd *cmd) +{ + struct rb_node **node, *parent = NULL; + struct xloop_worker *cur_worker, *worker = NULL; + struct work_struct *work; + struct list_head *cmd_list; + + spin_lock_irq(&xlo->xlo_work_lock); + + if (queue_on_root_worker(cmd->blkcg_css)) + goto queue_work; + + node = &xlo->worker_tree.rb_node; + + while (*node) { + parent = *node; + cur_worker = container_of(*node, struct xloop_worker, rb_node); + if (cur_worker->blkcg_css == cmd->blkcg_css) { + worker = cur_worker; + break; + } else if ((long)cur_worker->blkcg_css < (long)cmd->blkcg_css) { + node = &(*node)->rb_left; + } else { + node = &(*node)->rb_right; + } + } + if (worker) + goto queue_work; + + worker = kzalloc(sizeof(struct xloop_worker), GFP_NOWAIT | __GFP_NOWARN); + /* + * In the event we cannot allocate a worker, just queue on the + * rootcg worker and issue the I/O as the rootcg + */ + if (!worker) { + cmd->blkcg_css = NULL; + if (cmd->memcg_css) + css_put(cmd->memcg_css); + cmd->memcg_css = NULL; + goto queue_work; + } + + worker->blkcg_css = cmd->blkcg_css; + css_get(worker->blkcg_css); + INIT_WORK(&worker->work, xloop_workfn); + INIT_LIST_HEAD(&worker->cmd_list); + INIT_LIST_HEAD(&worker->idle_list); + worker->xlo = xlo; + rb_link_node(&worker->rb_node, parent, node); + rb_insert_color(&worker->rb_node, &xlo->worker_tree); +queue_work: + if (worker) { + /* + * We need to remove from the idle list here while + * holding the lock so that the idle timer doesn't + * free the worker + */ + if (!list_empty(&worker->idle_list)) + list_del_init(&worker->idle_list); + work = &worker->work; + cmd_list = &worker->cmd_list; + } else { + work = &xlo->rootcg_work; + cmd_list = &xlo->rootcg_cmd_list; + } + list_add_tail(&cmd->list_entry, cmd_list); + queue_work(xlo->workqueue, work); + spin_unlock_irq(&xlo->xlo_work_lock); +} + +static void xloop_set_timer(struct xloop_device *xlo) +{ + timer_reduce(&xlo->timer, jiffies + XLOOP_IDLE_WORKER_TIMEOUT); +} + +static void xloop_free_idle_workers(struct xloop_device *xlo, bool delete_all) +{ + struct xloop_worker *pos, *worker; + + spin_lock_irq(&xlo->xlo_work_lock); + list_for_each_entry_safe(worker, pos, &xlo->idle_worker_list, + idle_list) { + if (!delete_all && + time_is_after_jiffies(worker->last_ran_at + + XLOOP_IDLE_WORKER_TIMEOUT)) + break; + list_del(&worker->idle_list); + rb_erase(&worker->rb_node, &xlo->worker_tree); + css_put(worker->blkcg_css); + kfree(worker); + } + if (!list_empty(&xlo->idle_worker_list)) + xloop_set_timer(xlo); + spin_unlock_irq(&xlo->xlo_work_lock); +} + +static void xloop_free_idle_workers_timer(struct timer_list *timer) +{ + struct xloop_device *xlo = container_of(timer, struct xloop_device, timer); + + return xloop_free_idle_workers(xlo, false); +} + +static void xloop_update_rotational(struct xloop_device *xlo) +{ + struct file *file = xlo->xlo_backing_file; + struct inode *file_inode = file->f_mapping->host; + struct block_device *file_bdev = file_inode->i_sb->s_bdev; + struct request_queue *q = xlo->xlo_queue; + bool nonrot = true; + + /* not all filesystems (e.g. tmpfs) have a sb->s_bdev */ + if (file_bdev) + nonrot = bdev_nonrot(file_bdev); + + if (nonrot) + blk_queue_flag_set(QUEUE_FLAG_NONROT, q); + else + blk_queue_flag_clear(QUEUE_FLAG_NONROT, q); +} + +/** + * xloop_set_status_from_info - configure device from xloop_info + * @xlo: struct xloop_device to configure + * @info: struct xloop_info64 to configure the device with + * + * Configures the xloop device parameters according to the passed + * in xloop_info64 configuration. + */ +static int +xloop_set_status_from_info(struct xloop_device *xlo, + const struct xloop_info64 *info) +{ + if ((unsigned int) info->xlo_encrypt_key_size > XLO_KEY_SIZE) + return -EINVAL; + + switch (info->xlo_encrypt_type) { + case XLO_CRYPT_NONE: + break; + case XLO_CRYPT_XOR: + pr_warn("support for the xor transformation has been removed.\n"); + return -EINVAL; + case XLO_CRYPT_CRYPTOAPI: + pr_warn("support for cryptoloop has been removed. Use dm-crypt instead.\n"); + return -EINVAL; + default: + return -EINVAL; + } + + /* Avoid assigning overflow values */ + if (info->xlo_offset > LLONG_MAX || info->xlo_sizelimit > LLONG_MAX) + return -EOVERFLOW; + + xlo->xlo_offset = info->xlo_offset; + xlo->xlo_sizelimit = info->xlo_sizelimit; + + memcpy(xlo->xlo_file_name, info->xlo_file_name, XLO_NAME_SIZE); + xlo->xlo_file_name[XLO_NAME_SIZE-1] = 0; + xlo->xlo_flags = info->xlo_flags; + return 0; +} + +static int xloop_configure(struct xloop_device *xlo, blk_mode_t mode, + struct block_device *bdev, + const struct xloop_config *config) +{ + struct file *file = fget(config->fd); + struct inode *inode; + struct address_space *mapping; + int error; + loff_t size; + bool partscan; + unsigned short bsize; + bool is_xloop; + + if (!file) + return -EBADF; + is_xloop = is_xloop_device(file); + + /* This is safe, since we have a reference from open(). */ + __module_get(THIS_MODULE); + + /* + * If we don't hold exclusive handle for the device, upgrade to it + * here to avoid changing device under exclusive owner. + */ + if (!(mode & BLK_OPEN_EXCL)) { + error = bd_prepare_to_claim(bdev, xloop_configure, NULL); + if (error) + goto out_putf; + } + + error = xloop_global_lock_killable(xlo, is_xloop); + if (error) + goto out_bdev; + + error = -EBUSY; + if (xlo->xlo_state != Xlo_unbound) + goto out_unlock; + + error = xloop_validate_file(file, bdev); + if (error) + goto out_unlock; + + mapping = file->f_mapping; + inode = mapping->host; + + if ((config->info.xlo_flags & ~XLOOP_CONFIGURE_SETTABLE_FLAGS) != 0) { + error = -EINVAL; + goto out_unlock; + } + + if (config->block_size) { + error = blk_validate_block_size(config->block_size); + if (error) + goto out_unlock; + } + + error = xloop_set_status_from_info(xlo, &config->info); + if (error) + goto out_unlock; + + if (!(file->f_mode & FMODE_WRITE) || !(mode & BLK_OPEN_WRITE) || + !file->f_op->write_iter) + xlo->xlo_flags |= XLO_FLAGS_READ_ONLY; + + if (!xlo->workqueue) { + xlo->workqueue = alloc_workqueue("xloop%d", + WQ_UNBOUND | WQ_FREEZABLE, + 0, xlo->xlo_number); + if (!xlo->workqueue) { + error = -ENOMEM; + goto out_unlock; + } + } + + /* suppress uevents while reconfiguring the device */ + dev_set_uevent_suppress(disk_to_dev(xlo->xlo_disk), 1); + + disk_force_media_change(xlo->xlo_disk); + set_disk_ro(xlo->xlo_disk, (xlo->xlo_flags & XLO_FLAGS_READ_ONLY) != 0); + + xlo->use_dio = xlo->xlo_flags & XLO_FLAGS_DIRECT_IO; + xlo->xlo_device = bdev; + xlo->xlo_backing_file = file; + xlo->old_gfp_mask = mapping_gfp_mask(mapping); + mapping_set_gfp_mask(mapping, xlo->old_gfp_mask & ~(__GFP_IO|__GFP_FS)); + + error = xloop_file_fmt_init(xlo->xlo_fmt, config->info.xlo_file_fmt_type); + if (error) /* TODO: Undo stuff right above */ + goto out_unlock; + + if (!(xlo->xlo_flags & XLO_FLAGS_READ_ONLY) && file->f_op->fsync) + blk_queue_write_cache(xlo->xlo_queue, true, false); + + if (config->block_size) + bsize = config->block_size; + else if ((xlo->xlo_backing_file->f_flags & O_DIRECT) && inode->i_sb->s_bdev) + /* In case of direct I/O, match underlying block size */ + bsize = bdev_logical_block_size(inode->i_sb->s_bdev); + else + bsize = 512; + + blk_queue_logical_block_size(xlo->xlo_queue, bsize); + blk_queue_physical_block_size(xlo->xlo_queue, bsize); + blk_queue_io_min(xlo->xlo_queue, bsize); + + xloop_config_discard(xlo); + xloop_update_rotational(xlo); + xloop_update_dio(xlo); + xloop_sysfs_init(xlo); + + size = get_xloop_size(xlo, file); + xloop_set_size(xlo, size); + + /* Order wrt reading xlo_state in xloop_validate_file(). */ + wmb(); + + xlo->xlo_state = Xlo_bound; + if (part_shift) + xlo->xlo_flags |= XLO_FLAGS_PARTSCAN; + partscan = xlo->xlo_flags & XLO_FLAGS_PARTSCAN; + if (partscan) + clear_bit(GD_SUPPRESS_PART_SCAN, &xlo->xlo_disk->state); + + /* enable and uncork uevent now that we are done */ + dev_set_uevent_suppress(disk_to_dev(xlo->xlo_disk), 0); + + xloop_global_unlock(xlo, is_xloop); + if (partscan) + xloop_reread_partitions(xlo); + + if (!(mode & BLK_OPEN_EXCL)) + bd_abort_claiming(bdev, xloop_configure); + + return 0; + +out_unlock: + xloop_global_unlock(xlo, is_xloop); +out_bdev: + if (!(mode & BLK_OPEN_EXCL)) + bd_abort_claiming(bdev, xloop_configure); +out_putf: + fput(file); + /* This is safe: open() is still holding a reference. */ + module_put(THIS_MODULE); + return error; +} + +static void __xloop_clr_fd(struct xloop_device *xlo, bool release) +{ + struct file *filp; + gfp_t gfp = xlo->old_gfp_mask; + + if (test_bit(QUEUE_FLAG_WC, &xlo->xlo_queue->queue_flags)) + blk_queue_write_cache(xlo->xlo_queue, false, false); + + /* + * Freeze the request queue when unbinding on a live file descriptor and + * thus an open device. When called from ->release we are guaranteed + * that there is no I/O in progress already. + */ + if (!release) + blk_mq_freeze_queue(xlo->xlo_queue); + + xloop_file_fmt_exit(xlo->xlo_fmt); + + spin_lock_irq(&xlo->xlo_lock); + filp = xlo->xlo_backing_file; + xlo->xlo_backing_file = NULL; + spin_unlock_irq(&xlo->xlo_lock); + + xlo->xlo_device = NULL; + xlo->xlo_offset = 0; + xlo->xlo_sizelimit = 0; + memset(xlo->xlo_file_name, 0, XLO_NAME_SIZE); + blk_queue_logical_block_size(xlo->xlo_queue, 512); + blk_queue_physical_block_size(xlo->xlo_queue, 512); + blk_queue_io_min(xlo->xlo_queue, 512); + invalidate_disk(xlo->xlo_disk); + xloop_sysfs_exit(xlo); + /* let user-space know about this change */ + kobject_uevent(&disk_to_dev(xlo->xlo_disk)->kobj, KOBJ_CHANGE); + mapping_set_gfp_mask(filp->f_mapping, gfp); + /* This is safe: open() is still holding a reference. */ + module_put(THIS_MODULE); + if (!release) + blk_mq_unfreeze_queue(xlo->xlo_queue); + + disk_force_media_change(xlo->xlo_disk); + + if (xlo->xlo_flags & XLO_FLAGS_PARTSCAN) { + int err; + + /* + * open_mutex has been held already in release path, so don't + * acquire it if this function is called in such case. + * + * If the reread partition isn't from release path, xlo_refcnt + * must be at least one and it can only become zero when the + * current holder is released. + */ + if (!release) + mutex_lock(&xlo->xlo_disk->open_mutex); + err = bdev_disk_changed(xlo->xlo_disk, false); + if (!release) + mutex_unlock(&xlo->xlo_disk->open_mutex); + if (err) + pr_warn("%s: partition scan of xloop%d failed (rc=%d)\n", + __func__, xlo->xlo_number, err); + /* Device is gone, no point in returning error */ + } + + /* + * xlo->xlo_state is set to Xlo_unbound here after above partscan has + * finished. There cannot be anybody else entering __xloop_clr_fd() as + * Xlo_rundown state protects us from all the other places trying to + * change the 'xlo' device. + */ + xlo->xlo_flags = 0; + if (!part_shift) + set_bit(GD_SUPPRESS_PART_SCAN, &xlo->xlo_disk->state); + mutex_lock(&xlo->xlo_mutex); + xlo->xlo_state = Xlo_unbound; + mutex_unlock(&xlo->xlo_mutex); + + /* + * Need not hold xlo_mutex to fput backing file. Calling fput holding + * xlo_mutex triggers a circular lock dependency possibility warning as + * fput can take open_mutex which is usually taken before xlo_mutex. + */ + fput(filp); +} + +static int xloop_clr_fd(struct xloop_device *xlo) +{ + int err; + + /* + * Since xlo_ioctl() is called without locks held, it is possible that + * xloop_configure()/xloop_change_fd() and xloop_clr_fd() run in parallel. + * + * Therefore, use global lock when setting Xlo_rundown state in order to + * make sure that xloop_validate_file() will fail if the "struct file" + * which xloop_configure()/xloop_change_fd() found via fget() was this + * xloop device. + */ + err = xloop_global_lock_killable(xlo, true); + if (err) + return err; + if (xlo->xlo_state != Xlo_bound) { + xloop_global_unlock(xlo, true); + return -ENXIO; + } + /* + * If we've explicitly asked to tear down the xloop device, + * and it has an elevated reference count, set it for auto-teardown when + * the last reference goes away. This stops $!~#$@ udev from + * preventing teardown because it decided that it needs to run blkid on + * the xloopback device whenever they appear. xfstests is notorious for + * failing tests because blkid via udev races with a xlosetup + * <dev>/do something like mkfs/xlosetup -d <dev> causing the xlosetup -d + * command to fail with EBUSY. + */ + if (disk_openers(xlo->xlo_disk) > 1) { + xlo->xlo_flags |= XLO_FLAGS_AUTOCLEAR; + xloop_global_unlock(xlo, true); + return 0; + } + xlo->xlo_state = Xlo_rundown; + xloop_global_unlock(xlo, true); + + __xloop_clr_fd(xlo, false); + return 0; +} + +static int +xloop_set_status(struct xloop_device *xlo, const struct xloop_info64 *info) +{ + int err; + int prev_xlo_flags; + bool partscan = false; + bool size_changed = false; + + err = mutex_lock_killable(&xlo->xlo_mutex); + if (err) + return err; + if (xlo->xlo_state != Xlo_bound) { + err = -ENXIO; + goto out_unlock; + } + + if (xlo->xlo_offset != info->xlo_offset || + xlo->xlo_sizelimit != info->xlo_sizelimit) { + size_changed = true; + sync_blockdev(xlo->xlo_device); + invalidate_bdev(xlo->xlo_device); + } + + /* I/O need to be drained during transfer transition */ + blk_mq_freeze_queue(xlo->xlo_queue); + + prev_xlo_flags = xlo->xlo_flags; + + err = xloop_set_status_from_info(xlo, info); + if (err) + goto out_unfreeze; + + /* Mask out flags that can't be set using XLOOP_SET_STATUS. */ + xlo->xlo_flags &= XLOOP_SET_STATUS_SETTABLE_FLAGS; + /* For those flags, use the previous values instead */ + xlo->xlo_flags |= prev_xlo_flags & ~XLOOP_SET_STATUS_SETTABLE_FLAGS; + /* For flags that can't be cleared, use previous values too */ + xlo->xlo_flags |= prev_xlo_flags & ~XLOOP_SET_STATUS_CLEARABLE_FLAGS; + + if (xlo->xlo_fmt->file_fmt_type != info->xlo_file_fmt_type) { + /* xloop file format has changed, so change file format driver */ + err = xloop_file_fmt_change(xlo->xlo_fmt, info->xlo_file_fmt_type); + if (err) + goto out_unfreeze; + + /* After change of the file format, recalculate the capacity of the xloop device. */ + size_changed = true; + } + + if (size_changed) { + loff_t new_size = get_xloop_size(xlo, xlo->xlo_backing_file); + + xloop_set_size(xlo, new_size); + } + + xloop_config_discard(xlo); + + /* update dio if xlo_offset or transfer is changed */ + __xloop_update_dio(xlo, xlo->use_dio); + +out_unfreeze: + blk_mq_unfreeze_queue(xlo->xlo_queue); + + if (!err && (xlo->xlo_flags & XLO_FLAGS_PARTSCAN) && + !(prev_xlo_flags & XLO_FLAGS_PARTSCAN)) { + clear_bit(GD_SUPPRESS_PART_SCAN, &xlo->xlo_disk->state); + partscan = true; + } +out_unlock: + mutex_unlock(&xlo->xlo_mutex); + if (partscan) + xloop_reread_partitions(xlo); + + return err; +} + +static int +xloop_get_status(struct xloop_device *xlo, struct xloop_info64 *info) +{ + struct path path; + struct kstat stat; + int ret; + + ret = mutex_lock_killable(&xlo->xlo_mutex); + if (ret) + return ret; + if (xlo->xlo_state != Xlo_bound) { + mutex_unlock(&xlo->xlo_mutex); + return -ENXIO; + } + + memset(info, 0, sizeof(*info)); + info->xlo_number = xlo->xlo_number; + info->xlo_offset = xlo->xlo_offset; + info->xlo_sizelimit = xlo->xlo_sizelimit; + info->xlo_flags = xlo->xlo_flags; + memcpy(info->xlo_file_name, xlo->xlo_file_name, XLO_NAME_SIZE); + + /* Drop xlo_mutex while we call into the filesystem. */ + path = xlo->xlo_backing_file->f_path; + path_get(&path); + mutex_unlock(&xlo->xlo_mutex); + ret = vfs_getattr(&path, &stat, STATX_INO, AT_STATX_SYNC_AS_STAT); + if (!ret) { + info->xlo_device = huge_encode_dev(stat.dev); + info->xlo_inode = stat.ino; + info->xlo_rdevice = huge_encode_dev(stat.rdev); + } + path_put(&path); + return ret; +} + +static void +xloop_info64_from_old(const struct xloop_info *info, struct xloop_info64 *info64) +{ + memset(info64, 0, sizeof(*info64)); + info64->xlo_number = info->xlo_number; + info64->xlo_device = info->xlo_device; + info64->xlo_inode = info->xlo_inode; + info64->xlo_rdevice = info->xlo_rdevice; + info64->xlo_offset = info->xlo_offset; + info64->xlo_sizelimit = 0; + info64->xlo_flags = info->xlo_flags; + memcpy(info64->xlo_file_name, info->xlo_name, XLO_NAME_SIZE); +} + +static int +xloop_info64_to_old(const struct xloop_info64 *info64, struct xloop_info *info) +{ + memset(info, 0, sizeof(*info)); + info->xlo_number = info64->xlo_number; + info->xlo_device = info64->xlo_device; + info->xlo_inode = info64->xlo_inode; + info->xlo_rdevice = info64->xlo_rdevice; + info->xlo_offset = info64->xlo_offset; + info->xlo_flags = info64->xlo_flags; + memcpy(info->xlo_name, info64->xlo_file_name, XLO_NAME_SIZE); + + /* error in case values were truncated */ + if (info->xlo_device != info64->xlo_device || + info->xlo_rdevice != info64->xlo_rdevice || + info->xlo_inode != info64->xlo_inode || + info->xlo_offset != info64->xlo_offset) + return -EOVERFLOW; + + return 0; +} + +static int +xloop_set_status_old(struct xloop_device *xlo, const struct xloop_info __user *arg) +{ + struct xloop_info info; + struct xloop_info64 info64; + + if (copy_from_user(&info, arg, sizeof(struct xloop_info))) + return -EFAULT; + xloop_info64_from_old(&info, &info64); + return xloop_set_status(xlo, &info64); +} + +static int +xloop_set_status64(struct xloop_device *xlo, const struct xloop_info64 __user *arg) +{ + struct xloop_info64 info64; + + if (copy_from_user(&info64, arg, sizeof(struct xloop_info64))) + return -EFAULT; + return xloop_set_status(xlo, &info64); +} + +static int +xloop_get_status_old(struct xloop_device *xlo, struct xloop_info __user *arg) +{ + struct xloop_info info; + struct xloop_info64 info64; + int err; + + if (!arg) + return -EINVAL; + err = xloop_get_status(xlo, &info64); + if (!err) + err = xloop_info64_to_old(&info64, &info); + if (!err && copy_to_user(arg, &info, sizeof(info))) + err = -EFAULT; + + return err; +} + +static int +xloop_get_status64(struct xloop_device *xlo, struct xloop_info64 __user *arg) +{ + struct xloop_info64 info64; + int err; + + if (!arg) + return -EINVAL; + err = xloop_get_status(xlo, &info64); + if (!err && copy_to_user(arg, &info64, sizeof(info64))) + err = -EFAULT; + + return err; +} + +static int xloop_set_capacity(struct xloop_device *xlo) +{ + loff_t size; + + if (unlikely(xlo->xlo_state != Xlo_bound)) + return -ENXIO; + + size = get_xloop_size(xlo, xlo->xlo_backing_file); + xloop_set_size(xlo, size); + + return 0; +} + +static int xloop_set_dio(struct xloop_device *xlo, unsigned long arg) +{ + int error = -ENXIO; + + if (xlo->xlo_state != Xlo_bound) + goto out; + + __xloop_update_dio(xlo, !!arg); + if (xlo->use_dio == !!arg) + return 0; + error = -EINVAL; + out: + return error; +} + +static int xloop_set_block_size(struct xloop_device *xlo, unsigned long arg) +{ + int err = 0; + + if (xlo->xlo_state != Xlo_bound) + return -ENXIO; + + err = blk_validate_block_size(arg); + if (err) + return err; + + if (xlo->xlo_queue->limits.logical_block_size == arg) + return 0; + + sync_blockdev(xlo->xlo_device); + invalidate_bdev(xlo->xlo_device); + + blk_mq_freeze_queue(xlo->xlo_queue); + blk_queue_logical_block_size(xlo->xlo_queue, arg); + blk_queue_physical_block_size(xlo->xlo_queue, arg); + blk_queue_io_min(xlo->xlo_queue, arg); + xloop_update_dio(xlo); + blk_mq_unfreeze_queue(xlo->xlo_queue); + + return err; +} + +static int xlo_simple_ioctl(struct xloop_device *xlo, unsigned int cmd, + unsigned long arg) +{ + int err; + + err = mutex_lock_killable(&xlo->xlo_mutex); + if (err) + return err; + switch (cmd) { + case XLOOP_SET_CAPACITY: + err = xloop_set_capacity(xlo); + break; + case XLOOP_SET_DIRECT_IO: + err = xloop_set_dio(xlo, arg); + break; + case XLOOP_SET_BLOCK_SIZE: + err = xloop_set_block_size(xlo, arg); + break; + default: + err = -EINVAL; + } + mutex_unlock(&xlo->xlo_mutex); + return err; +} + +static int xlo_ioctl(struct block_device *bdev, blk_mode_t mode, + unsigned int cmd, unsigned long arg) +{ + struct xloop_device *xlo = bdev->bd_disk->private_data; + void __user *argp = (void __user *) arg; + int err; + + switch (cmd) { + case XLOOP_SET_FD: { + /* + * Legacy case - pass in a zeroed out struct xloop_config with + * only the file descriptor set , which corresponds with the + * default parameters we'd have used otherwise. + */ + struct xloop_config config; + + memset(&config, 0, sizeof(config)); + config.fd = arg; + + return xloop_configure(xlo, mode, bdev, &config); + } + case XLOOP_CONFIGURE: { + struct xloop_config config; + + if (copy_from_user(&config, argp, sizeof(config))) + return -EFAULT; + + return xloop_configure(xlo, mode, bdev, &config); + } + case XLOOP_CHANGE_FD: + return xloop_change_fd(xlo, bdev, arg); + case XLOOP_CLR_FD: + return xloop_clr_fd(xlo); + case XLOOP_SET_STATUS: + err = -EPERM; + if ((mode & BLK_OPEN_WRITE) || capable(CAP_SYS_ADMIN)) + err = xloop_set_status_old(xlo, argp); + break; + case XLOOP_GET_STATUS: + return xloop_get_status_old(xlo, argp); + case XLOOP_SET_STATUS64: + err = -EPERM; + if ((mode & BLK_OPEN_WRITE) || capable(CAP_SYS_ADMIN)) + err = xloop_set_status64(xlo, argp); + break; + case XLOOP_GET_STATUS64: + return xloop_get_status64(xlo, argp); + case XLOOP_SET_CAPACITY: + case XLOOP_SET_DIRECT_IO: + case XLOOP_SET_BLOCK_SIZE: + if (!(mode & BLK_OPEN_WRITE) && !capable(CAP_SYS_ADMIN)) + return -EPERM; + fallthrough; + default: + err = xlo_simple_ioctl(xlo, cmd, arg); + break; + } + + return err; +} + +#ifdef CONFIG_COMPAT +struct compat_xloop_info { + compat_int_t xlo_number; /* ioctl r/o */ + compat_dev_t xlo_device; /* ioctl r/o */ + compat_ulong_t xlo_inode; /* ioctl r/o */ + compat_dev_t xlo_rdevice; /* ioctl r/o */ + compat_int_t xlo_offset; + compat_int_t xlo_encrypt_type; /* obsolete, ignored */ + compat_int_t xlo_encrypt_key_size; /* ioctl w/o */ + compat_int_t xlo_flags; /* ioctl r/o */ + char xlo_name[XLO_NAME_SIZE]; + unsigned char xlo_encrypt_key[XLO_KEY_SIZE]; /* ioctl w/o */ + compat_ulong_t xlo_init[2]; + char reserved[4]; +}; + +/* + * Transfer 32-bit compatibility structure in userspace to 64-bit xloop info + * - noinlined to reduce stack space usage in main part of driver + */ +static noinline int +xloop_info64_from_compat(const struct compat_xloop_info __user *arg, + struct xloop_info64 *info64) +{ + struct compat_xloop_info info; + + if (copy_from_user(&info, arg, sizeof(info))) + return -EFAULT; + + memset(info64, 0, sizeof(*info64)); + info64->xlo_number = info.xlo_number; + info64->xlo_device = info.xlo_device; + info64->xlo_inode = info.xlo_inode; + info64->xlo_rdevice = info.xlo_rdevice; + info64->xlo_offset = info.xlo_offset; + info64->xlo_sizelimit = 0; + info64->xlo_flags = info.xlo_flags; + memcpy(info64->xlo_file_name, info.xlo_name, XLO_NAME_SIZE); + return 0; +} + +/* + * Transfer 64-bit xloop info to 32-bit compatibility structure in userspace + * - noinlined to reduce stack space usage in main part of driver + */ +static noinline int +xloop_info64_to_compat(const struct xloop_info64 *info64, + struct compat_xloop_info __user *arg) +{ + struct compat_xloop_info info; + + memset(&info, 0, sizeof(info)); + info.xlo_number = info64->xlo_number; + info.xlo_device = info64->xlo_device; + info.xlo_inode = info64->xlo_inode; + info.xlo_rdevice = info64->xlo_rdevice; + info.xlo_offset = info64->xlo_offset; + info.xlo_flags = info64->xlo_flags; + memcpy(info.xlo_name, info64->xlo_file_name, XLO_NAME_SIZE); + + /* error in case values were truncated */ + if (info.xlo_device != info64->xlo_device || + info.xlo_rdevice != info64->xlo_rdevice || + info.xlo_inode != info64->xlo_inode || + info.xlo_offset != info64->xlo_offset) + return -EOVERFLOW; + + if (copy_to_user(arg, &info, sizeof(info))) + return -EFAULT; + return 0; +} + +static int +xloop_set_status_compat(struct xloop_device *xlo, + const struct compat_xloop_info __user *arg) +{ + struct xloop_info64 info64; + int ret; + + ret = xloop_info64_from_compat(arg, &info64); + if (ret < 0) + return ret; + return xloop_set_status(xlo, &info64); +} + +static int +xloop_get_status_compat(struct xloop_device *xlo, + struct compat_xloop_info __user *arg) +{ + struct xloop_info64 info64; + int err; + + if (!arg) + return -EINVAL; + err = xloop_get_status(xlo, &info64); + if (!err) + err = xloop_info64_to_compat(&info64, arg); + return err; +} + +static int xlo_compat_ioctl(struct block_device *bdev, blk_mode_t mode, + unsigned int cmd, unsigned long arg) +{ + struct xloop_device *xlo = bdev->bd_disk->private_data; + int err; + + switch (cmd) { + case XLOOP_SET_STATUS: + err = xloop_set_status_compat(xlo, + (const struct compat_xloop_info __user *)arg); + break; + case XLOOP_GET_STATUS: + err = xloop_get_status_compat(xlo, + (struct compat_xloop_info __user *)arg); + break; + case XLOOP_SET_CAPACITY: + case XLOOP_CLR_FD: + case XLOOP_GET_STATUS64: + case XLOOP_SET_STATUS64: + case XLOOP_CONFIGURE: + arg = (unsigned long) compat_ptr(arg); + fallthrough; + case XLOOP_SET_FD: + case XLOOP_CHANGE_FD: + case XLOOP_SET_BLOCK_SIZE: + case XLOOP_SET_DIRECT_IO: + err = xlo_ioctl(bdev, mode, cmd, arg); + break; + default: + err = -ENOIOCTLCMD; + break; + } + return err; +} +#endif + +static void xlo_release(struct gendisk *disk) +{ + struct xloop_device *xlo = disk->private_data; + + if (disk_openers(disk) > 0) + return; + + mutex_lock(&xlo->xlo_mutex); + if (xlo->xlo_state == Xlo_bound && (xlo->xlo_flags & XLO_FLAGS_AUTOCLEAR)) { + xlo->xlo_state = Xlo_rundown; + mutex_unlock(&xlo->xlo_mutex); + /* + * In autoclear mode, stop the xloop thread + * and remove configuration after last close. + */ + __xloop_clr_fd(xlo, true); + return; + } + mutex_unlock(&xlo->xlo_mutex); +} + +static void xlo_free_disk(struct gendisk *disk) +{ + struct xloop_device *xlo = disk->private_data; + + if (xlo->workqueue) + destroy_workqueue(xlo->workqueue); + xloop_free_idle_workers(xlo, true); + timer_shutdown_sync(&xlo->timer); + mutex_destroy(&xlo->xlo_mutex); + kfree(xlo); +} + +static const struct block_device_operations xlo_fops = { + .owner = THIS_MODULE, + .release = xlo_release, + .ioctl = xlo_ioctl, +#ifdef CONFIG_COMPAT + .compat_ioctl = xlo_compat_ioctl, +#endif + .free_disk = xlo_free_disk, +}; + +/* + * And now the modules code and kernel interface. + */ + +/* + * If max_xloop is specified, create that many devices upfront. + * This also becomes a hard limit. If max_xloop is not specified, + * the default isn't a hard limit (as before commit 85c50197716c + * changed the default value from 0 for max_xloop=0 reasons), just + * create CONFIG_BLK_DEV_XLOOP_MIN_COUNT xloop devices at module + * init time. Loop devices can be requested on-demand with the + * /dev/loop-control interface, or be instantiated by accessing + * a 'dead' device node. + */ +static int max_xloop = CONFIG_BLK_DEV_XLOOP_MIN_COUNT; + +#ifdef CONFIG_BLOCK_LEGACY_AUTOLOAD +static bool max_xloop_specified; + +static int max_xloop_param_set_int(const char *val, + const struct kernel_param *kp) +{ + int ret; + + ret = param_set_int(val, kp); + if (ret < 0) + return ret; + + max_xloop_specified = true; + return 0; +} + +static const struct kernel_param_ops max_xloop_param_ops = { + .set = max_xloop_param_set_int, + .get = param_get_int, +}; + +module_param_cb(max_xloop, &max_xloop_param_ops, &max_xloop, 0444); +MODULE_PARM_DESC(max_xloop, "Maximum number of xloop devices"); +#else +module_param(max_xloop, int, 0444); +MODULE_PARM_DESC(max_xloop, "Initial number of xloop devices"); +#endif + +module_param(max_part, int, 0444); +MODULE_PARM_DESC(max_part, "Maximum number of partitions per xloop device"); + +static int hw_queue_depth = XLOOP_DEFAULT_HW_Q_DEPTH; + +static int xloop_set_hw_queue_depth(const char *s, const struct kernel_param *p) +{ + int qd, ret; + + ret = kstrtoint(s, 0, &qd); + if (ret < 0) + return ret; + if (qd < 1) + return -EINVAL; + hw_queue_depth = qd; + return 0; +} + +static const struct kernel_param_ops xloop_hw_qdepth_param_ops = { + .set = xloop_set_hw_queue_depth, + .get = param_get_int, +}; + +device_param_cb(hw_queue_depth, &xloop_hw_qdepth_param_ops, &hw_queue_depth, 0444); +MODULE_PARM_DESC(hw_queue_depth, "Queue depth for each hardware queue. Default: " __stringify(XLOOP_DEFAULT_HW_Q_DEPTH)); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Manuel Bentele <development@manuel-bentele.de>"); +MODULE_VERSION(XLOOP_VERSION); +MODULE_ALIAS_BLOCKDEV_MAJOR(XLOOP_MAJOR); + +static blk_status_t xloop_queue_rq(struct blk_mq_hw_ctx *hctx, + const struct blk_mq_queue_data *bd) +{ + struct request *rq = bd->rq; + struct xloop_cmd *cmd = blk_mq_rq_to_pdu(rq); + struct xloop_device *xlo = rq->q->queuedata; + + blk_mq_start_request(rq); + + if (xlo->xlo_state != Xlo_bound) + return BLK_STS_IOERR; + + switch (req_op(rq)) { + case REQ_OP_FLUSH: + case REQ_OP_DISCARD: + case REQ_OP_WRITE_ZEROES: + cmd->use_aio = false; + break; + default: + cmd->use_aio = xlo->use_dio; + break; + } + + /* always use the first bio's css */ + cmd->blkcg_css = NULL; + cmd->memcg_css = NULL; +#ifdef CONFIG_BLK_CGROUP + if (rq->bio) { + cmd->blkcg_css = bio_blkcg_css(rq->bio); +#ifdef CONFIG_MEMCG + if (cmd->blkcg_css) { + cmd->memcg_css = + cgroup_get_e_css(cmd->blkcg_css->cgroup, + &memory_cgrp_subsys); + } +#endif + } +#endif + xloop_queue_work(xlo, cmd); + + return BLK_STS_OK; +} + +static void xloop_handle_cmd(struct xloop_cmd *cmd) +{ + struct cgroup_subsys_state *cmd_blkcg_css = cmd->blkcg_css; + struct cgroup_subsys_state *cmd_memcg_css = cmd->memcg_css; + struct request *rq = blk_mq_rq_from_pdu(cmd); + const bool write = op_is_write(req_op(rq)); + struct xloop_device *xlo = rq->q->queuedata; + int ret = 0; + struct mem_cgroup *old_memcg = NULL; + const bool use_aio = cmd->use_aio; + + if (write && (xlo->xlo_flags & XLO_FLAGS_READ_ONLY)) { + ret = -EIO; + goto failed; + } + + if (cmd_blkcg_css) + kthread_associate_blkcg(cmd_blkcg_css); + if (cmd_memcg_css) + old_memcg = set_active_memcg( + mem_cgroup_from_css(cmd_memcg_css)); + + /* + * do_req_filebacked() may call blk_mq_complete_request() synchronously + * or asynchronously if using aio. Hence, do not touch 'cmd' after + * do_req_filebacked() has returned unless we are sure that 'cmd' has + * not yet been completed. + */ + ret = do_req_filebacked(xlo, rq); + + if (cmd_blkcg_css) + kthread_associate_blkcg(NULL); + + if (cmd_memcg_css) { + set_active_memcg(old_memcg); + css_put(cmd_memcg_css); + } + failed: + /* complete non-aio request */ + if (!use_aio || ret) { + if (ret == -EOPNOTSUPP) + cmd->ret = ret; + else + cmd->ret = ret ? -EIO : 0; + if (likely(!blk_should_fake_timeout(rq->q))) + blk_mq_complete_request(rq); + } +} + +static void xloop_process_work(struct xloop_worker *worker, + struct list_head *cmd_list, struct xloop_device *xlo) +{ + int orig_flags = current->flags; + struct xloop_cmd *cmd; + + current->flags |= PF_LOCAL_THROTTLE | PF_MEMALLOC_NOIO; + spin_lock_irq(&xlo->xlo_work_lock); + while (!list_empty(cmd_list)) { + cmd = container_of( + cmd_list->next, struct xloop_cmd, list_entry); + list_del(cmd_list->next); + spin_unlock_irq(&xlo->xlo_work_lock); + + xloop_handle_cmd(cmd); + cond_resched(); + + spin_lock_irq(&xlo->xlo_work_lock); + } + + /* + * We only add to the idle list if there are no pending cmds + * *and* the worker will not run again which ensures that it + * is safe to free any worker on the idle list + */ + if (worker && !work_pending(&worker->work)) { + worker->last_ran_at = jiffies; + list_add_tail(&worker->idle_list, &xlo->idle_worker_list); + xloop_set_timer(xlo); + } + spin_unlock_irq(&xlo->xlo_work_lock); + current->flags = orig_flags; +} + +static void xloop_workfn(struct work_struct *work) +{ + struct xloop_worker *worker = + container_of(work, struct xloop_worker, work); + xloop_process_work(worker, &worker->cmd_list, worker->xlo); +} + +static void xloop_rootcg_workfn(struct work_struct *work) +{ + struct xloop_device *xlo = + container_of(work, struct xloop_device, rootcg_work); + xloop_process_work(NULL, &xlo->rootcg_cmd_list, xlo); +} + +static const struct blk_mq_ops xloop_mq_ops = { + .queue_rq = xloop_queue_rq, + .complete = xlo_complete_rq, +}; + +#ifdef CONFIG_DEBUG_FS +static struct dentry *xloop_dbgfs_dir; +#endif + +static int xloop_add(int i) +{ + struct xloop_device *xlo; + struct gendisk *disk; + int err; + + err = -ENOMEM; + xlo = kzalloc(sizeof(*xlo), GFP_KERNEL); + if (!xlo) + goto out; + xlo->worker_tree = RB_ROOT; + INIT_LIST_HEAD(&xlo->idle_worker_list); + timer_setup(&xlo->timer, xloop_free_idle_workers_timer, TIMER_DEFERRABLE); + xlo->xlo_state = Xlo_unbound; + + err = mutex_lock_killable(&xloop_ctl_mutex); + if (err) + goto out_free_dev; + + /* allocate id, if @id >= 0, we're requesting that specific id */ + if (i >= 0) { + err = idr_alloc(&xloop_index_idr, xlo, i, i + 1, GFP_KERNEL); + if (err == -ENOSPC) + err = -EEXIST; + } else { + err = idr_alloc(&xloop_index_idr, xlo, 0, 0, GFP_KERNEL); + } + mutex_unlock(&xloop_ctl_mutex); + if (err < 0) + goto out_free_dev; + i = err; + + xlo->tag_set.ops = &xloop_mq_ops; + xlo->tag_set.nr_hw_queues = 1; + xlo->tag_set.queue_depth = hw_queue_depth; + xlo->tag_set.numa_node = NUMA_NO_NODE; + xlo->tag_set.cmd_size = sizeof(struct xloop_cmd); + xlo->tag_set.flags = BLK_MQ_F_SHOULD_MERGE | BLK_MQ_F_STACKING | + BLK_MQ_F_NO_SCHED_BY_DEFAULT; + xlo->tag_set.driver_data = xlo; + + err = blk_mq_alloc_tag_set(&xlo->tag_set); + if (err) + goto out_free_idr; + + disk = xlo->xlo_disk = blk_mq_alloc_disk(&xlo->tag_set, xlo); + if (IS_ERR(disk)) { + err = PTR_ERR(disk); + goto out_cleanup_tags; + } + xlo->xlo_queue = xlo->xlo_disk->queue; + + blk_queue_max_hw_sectors(xlo->xlo_queue, BLK_DEF_MAX_SECTORS); + + /* + * By default, we do buffer IO, so it doesn't make sense to enable + * merge because the I/O submitted to backing file is handled page by + * page. For directio mode, merge does help to dispatch bigger request + * to underlayer disk. We will enable merge once directio is enabled. + */ + blk_queue_flag_set(QUEUE_FLAG_NOMERGES, xlo->xlo_queue); + + err = -ENOMEM; + xlo->xlo_fmt = xloop_file_fmt_alloc(); + if (!xlo->xlo_fmt) + goto out_cleanup_disk; + + xloop_file_fmt_set_xlo(xlo->xlo_fmt, xlo); + + /* + * Disable partition scanning by default. The in-kernel partition + * scanning can be requested individually per-device during its + * setup. Userspace can always add and remove partitions from all + * devices. The needed partition minors are allocated from the + * extended minor space, the main xloop device numbers will continue + * to match the xloop minors, regardless of the number of partitions + * used. + * + * If max_part is given, partition scanning is globally enabled for + * all xloop devices. The minors for the main xloop devices will be + * multiples of max_part. + * + * Note: Global-for-all-devices, set-only-at-init, read-only module + * parameteters like 'max_xloop' and 'max_part' make things needlessly + * complicated, are too static, inflexible and may surprise + * userspace tools. Parameters like this in general should be avoided. + */ + if (!part_shift) + set_bit(GD_SUPPRESS_PART_SCAN, &disk->state); + mutex_init(&xlo->xlo_mutex); + xlo->xlo_number = i; + spin_lock_init(&xlo->xlo_lock); + spin_lock_init(&xlo->xlo_work_lock); + INIT_WORK(&xlo->rootcg_work, xloop_rootcg_workfn); + INIT_LIST_HEAD(&xlo->rootcg_cmd_list); + disk->major = XLOOP_MAJOR; + disk->first_minor = i << part_shift; + disk->minors = 1 << part_shift; + disk->fops = &xlo_fops; + disk->private_data = xlo; + disk->queue = xlo->xlo_queue; + disk->events = DISK_EVENT_MEDIA_CHANGE; + disk->event_flags = DISK_EVENT_FLAG_UEVENT; + sprintf(disk->disk_name, "xloop%d", i); + /* Make this xloop device reachable from pathname. */ + err = add_disk(disk); + if (err) + goto out_free_file_fmt; + + /* Show this xloop device. */ + mutex_lock(&xloop_ctl_mutex); + xlo->idr_visible = true; + mutex_unlock(&xloop_ctl_mutex); + + /* + * initialize debugfs entries + * + * create for each xloop device a debugfs directory under 'xloop' if + * the 'block' directory exists, otherwise create the loop directory in + * the root directory + */ +#ifdef CONFIG_DEBUG_FS + xlo->xlo_dbgfs_dir = debugfs_create_dir(disk->disk_name, xloop_dbgfs_dir); + + if (IS_ERR_OR_NULL(xlo->xlo_dbgfs_dir)) { + err = -ENODEV; + xlo->xlo_dbgfs_dir = NULL; + goto out_free_file_fmt; + } +#endif + + return i; + +out_free_file_fmt: + xloop_file_fmt_free(xlo->xlo_fmt); +out_cleanup_disk: + put_disk(disk); +out_cleanup_tags: + blk_mq_free_tag_set(&xlo->tag_set); +out_free_idr: + mutex_lock(&xloop_ctl_mutex); + idr_remove(&xloop_index_idr, i); + mutex_unlock(&xloop_ctl_mutex); +out_free_dev: + kfree(xlo); +out: + return err; +} + +static void xloop_remove(struct xloop_device *xlo) +{ + xloop_file_fmt_free(xlo->xlo_fmt); +#ifdef CONFIG_DEBUG_FS + debugfs_remove(xlo->xlo_dbgfs_dir); +#endif + /* Make this xloop device unreachable from pathname. */ + del_gendisk(xlo->xlo_disk); + blk_mq_free_tag_set(&xlo->tag_set); + + mutex_lock(&xloop_ctl_mutex); + idr_remove(&xloop_index_idr, xlo->xlo_number); + mutex_unlock(&xloop_ctl_mutex); + + put_disk(xlo->xlo_disk); +} + +#ifdef CONFIG_BLOCK_LEGACY_AUTOLOAD +static void xloop_probe(dev_t dev) +{ + int idx = MINOR(dev) >> part_shift; + + if (max_xloop_specified && max_xloop && idx >= max_xloop) + return; + xloop_add(idx); +} +#else +#define xloop_probe NULL +#endif /* !CONFIG_BLOCK_LEGACY_AUTOLOAD */ + +static int xloop_control_remove(int idx) +{ + struct xloop_device *xlo; + int ret; + + if (idx < 0) { + pr_warn_once("deleting an unspecified xloop device is not supported.\n"); + return -EINVAL; + } + + /* Hide this xloop device for serialization. */ + ret = mutex_lock_killable(&xloop_ctl_mutex); + if (ret) + return ret; + xlo = idr_find(&xloop_index_idr, idx); + if (!xlo || !xlo->idr_visible) + ret = -ENODEV; + else + xlo->idr_visible = false; + mutex_unlock(&xloop_ctl_mutex); + if (ret) + return ret; + + /* Check whether this xloop device can be removed. */ + ret = mutex_lock_killable(&xlo->xlo_mutex); + if (ret) + goto mark_visible; + if (xlo->xlo_state != Xlo_unbound || disk_openers(xlo->xlo_disk) > 0) { + mutex_unlock(&xlo->xlo_mutex); + ret = -EBUSY; + goto mark_visible; + } + /* Mark this xloop device as no more bound, but not quite unbound yet */ + xlo->xlo_state = Xlo_deleting; + mutex_unlock(&xlo->xlo_mutex); + + xloop_remove(xlo); + return 0; + +mark_visible: + /* Show this xloop device again. */ + mutex_lock(&xloop_ctl_mutex); + xlo->idr_visible = true; + mutex_unlock(&xloop_ctl_mutex); + return ret; +} + +static int xloop_control_get_free(int idx) +{ + struct xloop_device *xlo; + int id, ret; + + ret = mutex_lock_killable(&xloop_ctl_mutex); + if (ret) + return ret; + idr_for_each_entry(&xloop_index_idr, xlo, id) { + /* Hitting a race results in creating a new xloop device which is harmless. */ + if (xlo->idr_visible && data_race(xlo->xlo_state) == Xlo_unbound) + goto found; + } + mutex_unlock(&xloop_ctl_mutex); + return xloop_add(-1); +found: + mutex_unlock(&xloop_ctl_mutex); + return id; +} + +static long xloop_control_ioctl(struct file *file, unsigned int cmd, + unsigned long parm) +{ + switch (cmd) { + case XLOOP_CTL_ADD: + return xloop_add(parm); + case XLOOP_CTL_REMOVE: + return xloop_control_remove(parm); + case XLOOP_CTL_GET_FREE: + return xloop_control_get_free(parm); + default: + return -ENOSYS; + } +} + +static const struct file_operations xloop_ctl_fops = { + .open = nonseekable_open, + .unlocked_ioctl = xloop_control_ioctl, + .compat_ioctl = xloop_control_ioctl, + .owner = THIS_MODULE, + .llseek = noop_llseek, +}; + +static struct miscdevice xloop_misc = { + .minor = XLOOP_CTRL_MINOR, + .name = "xloop-control", + .fops = &xloop_ctl_fops, +}; + +MODULE_ALIAS_MISCDEV(XLOOP_CTRL_MINOR); +MODULE_ALIAS("devname:xloop-control"); + +static int __init xloop_init(void) +{ + int i; + int err; + + part_shift = 0; + if (max_part > 0) { + part_shift = fls(max_part); + + /* + * Adjust max_part according to part_shift as it is exported + * to user space so that user can decide correct minor number + * if [s]he want to create more devices. + * + * Note that -1 is required because partition 0 is reserved + * for the whole disk. + */ + max_part = (1UL << part_shift) - 1; + } + + if ((1UL << part_shift) > DISK_MAX_PARTS) { + err = -EINVAL; + goto err_out; + } + + if (max_xloop > 1UL << (MINORBITS - part_shift)) { + err = -EINVAL; + goto err_out; + } + + err = misc_register(&xloop_misc); + if (err < 0) + goto err_out; + + + if (__register_blkdev(XLOOP_MAJOR, "xloop", xloop_probe)) { + err = -EIO; + goto misc_out; + } + +#ifdef CONFIG_DEBUG_FS + xloop_dbgfs_dir = debugfs_create_dir("xloop", NULL); + if (IS_ERR_OR_NULL(xloop_dbgfs_dir)) { + err = -ENODEV; + goto blkdev_out; + } +#endif + + /* pre-create number of devices given by config or max_xloop */ + for (i = 0; i < max_xloop; i++) + xloop_add(i); + + pr_info("module (version %s) loaded\n", XLOOP_VERSION); + return 0; + +#ifdef CONFIG_DEBUG_FS +blkdev_out: + unregister_blkdev(XLOOP_MAJOR, "xloop"); +#endif +misc_out: + misc_deregister(&xloop_misc); +err_out: + return err; +} + +static void __exit xloop_exit(void) +{ + struct xloop_device *xlo; + int id; + + unregister_blkdev(XLOOP_MAJOR, "xloop"); + misc_deregister(&xloop_misc); + + /* + * There is no need to use xloop_ctl_mutex here, for nobody else can + * access xloop_index_idr when this module is unloading (unless forced + * module unloading is requested). If this is not a clean unloading, + * we have no means to avoid kernel crash. + */ + idr_for_each_entry(&xloop_index_idr, xlo, id) + xloop_remove(xlo); + + idr_destroy(&xloop_index_idr); + +#ifdef CONFIG_DEBUG_FS + debugfs_remove(xloop_dbgfs_dir); +#endif + + pr_info("exit module\n"); +} + +module_init(xloop_init); +module_exit(xloop_exit); + +#ifndef MODULE +static int __init max_xloop_setup(char *str) +{ + max_xloop = simple_strtol(str, NULL, 0); +#ifdef CONFIG_BLOCK_LEGACY_AUTOLOAD + max_xloop_specified = true; +#endif + return 1; +} + +__setup("max_xloop=", max_xloop_setup); +#endif diff --git a/src/kernel/xloop_main_6.6.h b/src/kernel/xloop_main_6.6.h new file mode 100644 index 0000000..94e523d --- /dev/null +++ b/src/kernel/xloop_main_6.6.h @@ -0,0 +1,98 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * loop_main.h + * + * Written by Theodore Ts'o, 3/29/93. + * + * Copyright 1993 by Theodore Ts'o. Redistribution of this file is + * permitted under the GNU General Public License. + */ +#ifndef _LINUX_XLOOP_H +#define _LINUX_XLOOP_H + +#include <linux/bio.h> +#include <linux/blkdev.h> +#include <linux/blk-mq.h> +#include <linux/spinlock.h> +#include <linux/mutex.h> +#include "uapi_xloop.h" +#ifdef CONFIG_DEBUG_FS +#include <linux/debugfs.h> +#endif + +#include "xloop_file_fmt.h" + +/* Possible states of device */ +enum { + Xlo_unbound, + Xlo_bound, + Xlo_rundown, + Xlo_deleting, +}; + +struct xloop_func_table; + +struct xloop_device { + int xlo_number; + loff_t xlo_offset; + loff_t xlo_sizelimit; + int xlo_flags; + char xlo_file_name[XLO_NAME_SIZE]; + + struct xloop_file_fmt *xlo_fmt; + + struct file *xlo_backing_file; + struct block_device *xlo_device; + + gfp_t old_gfp_mask; + + spinlock_t xlo_lock; + int xlo_state; + spinlock_t xlo_work_lock; + struct workqueue_struct *workqueue; + struct work_struct rootcg_work; + struct list_head rootcg_cmd_list; + struct list_head idle_worker_list; + struct rb_root worker_tree; + struct timer_list timer; + bool use_dio; + bool sysfs_inited; + + struct request_queue *xlo_queue; + struct blk_mq_tag_set tag_set; + struct gendisk *xlo_disk; + struct mutex xlo_mutex; + bool idr_visible; + +#ifdef CONFIG_DEBUG_FS + struct dentry *xlo_dbgfs_dir; +#endif +}; + +struct xloop_cmd { + struct list_head list_entry; + bool use_aio; /* use AIO interface to handle I/O */ + atomic_t ref; /* only for aio */ + long ret; + struct kiocb iocb; + struct bio_vec *bvec; + struct cgroup_subsys_state *blkcg_css; + struct cgroup_subsys_state *memcg_css; +}; + +/* Support for loadable transfer modules */ +struct xloop_func_table { + int number; /* filter type */ + int (*transfer)(struct xloop_device *xlo, int cmd, struct page *raw_page, unsigned raw_off, struct page *xloop_page, unsigned xloop_off, int size, sector_t real_block); + int (*init)(struct xloop_device *xlo, const struct xloop_info64 *info); + /* release is called from xloop_unregister_transfer or clr_fd */ + int (*release)(struct xloop_device *xlo); + struct module *owner; +}; + +extern inline struct device *xloop_device_to_dev(struct xloop_device *xlo); + +int xloop_register_transfer(struct xloop_func_table *funcs); +int xloop_unregister_transfer(int number); + +#endif |