diff options
Diffstat (limited to 'src/kernel/xloop_main.c')
| -rw-r--r-- | src/kernel/xloop_main.c | 2412 |
1 files changed, 3 insertions, 2409 deletions
diff --git a/src/kernel/xloop_main.c b/src/kernel/xloop_main.c index d133709..b3f7963 100644 --- a/src/kernel/xloop_main.c +++ b/src/kernel/xloop_main.c @@ -1,2413 +1,7 @@ -// SPDX-License-Identifier: GPL-2.0 -/* - * xloop_main.c - * - * 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. - * - * DES encryption plus some minor changes by Werner Almesberger, 30-MAY-1993 - * more DES encryption plus IDEA encryption by Nicholas J. Leon, June 20, 1996 - * - * Modularized and updated for 1.1.16 kernel - Mitch Dsouza 28th May 1994 - * Adapted for 1.3.59 kernel - Andries Brouwer, 1 Feb 1996 - * - * Fixed do_xloop_request() re-entrancy - Vincent.Renardias@waw.com Mar 20, 1997 - * - * Added devfs support - Richard Gooch <rgooch@atnf.csiro.au> 16-Jan-1998 - * - * Handle sparse backing files correctly - Kenn Humborg, Jun 28, 1998 - * - * Loadable modules and other fixes by AK, 1998 - * - * Make real block number available to downstream transfer functions, enables - * CBC (and relatives) mode encryption requiring unique IVs per data block. - * Reed H. Petty, rhp@draper.net - * - * Maximum number of xloop devices now dynamic via max_xloop module parameter. - * Russell Kroll <rkroll@exploits.org> 19990701 - * - * Maximum number of xloop devices when compiled-in now selectable by passing - * max_xloop=<1-255> to the kernel on boot. - * Erik I. Bolsø, <eriki@himolde.no>, Oct 31, 1999 - * - * Completely rewrite request handling to be make_request_fn style and - * non blocking, pushing work to a helper thread. Lots of fixes from - * Al Viro too. - * Jens Axboe <axboe@suse.de>, Nov 2000 - * - * Support up to 256 xloop devices - * Heinz Mauelshagen <mge@sistina.com>, Feb 2002 - * - * Support for falling back on the write file operation when the address space - * operations write_begin is not available on the backing filesystem. - * Anton Altaparmakov, 16 Feb 2005 - * - * Support for using file formats. - * Manuel Bentele <development@manuel-bentele.de>, 2019 - * - * Still To Fix: - * - Advisory locking is ignored here. - * - Should use an own CAP_* category instead of CAP_SYS_ADMIN - * - */ - -#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt - -#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/blkdev.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/version.h> -#ifdef CONFIG_DEBUG_FS -#include <linux/debugfs.h> -#endif - -#include <xloop/version.h> - -#include "xloop_file_fmt.h" -#include "xloop_main.h" - -#include <linux/uaccess.h> - -#define XLOOP_IDLE_WORKER_TIMEOUT (60 * HZ) - -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 int transfer_xor(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) -{ - char *raw_buf = kmap_atomic(raw_page) + raw_off; - char *xloop_buf = kmap_atomic(xloop_page) + xloop_off; - char *in, *out, *key; - int i, keysize; - - if (cmd == READ) { - in = raw_buf; - out = xloop_buf; - } else { - in = xloop_buf; - out = raw_buf; - } - - key = xlo->xlo_encrypt_key; - keysize = xlo->xlo_encrypt_key_size; - for (i = 0; i < size; i++) - *out++ = *in++ ^ key[(i & 511) % keysize]; - - kunmap_atomic(xloop_buf); - kunmap_atomic(raw_buf); - cond_resched(); - return 0; -} - -static int xor_init(struct xloop_device *xlo, const struct xloop_info64 *info) -{ - if (unlikely(info->xlo_encrypt_key_size <= 0)) - return -EINVAL; - return 0; -} - -static struct xloop_func_table none_funcs = { - .number = XLO_CRYPT_NONE, -}; - -static struct xloop_func_table xor_funcs = { - .number = XLO_CRYPT_XOR, - .transfer = transfer_xor, - .init = xor_init -}; - -/* xfer_funcs[0] is special - its release function is never called */ -static struct xloop_func_table *xfer_funcs[MAX_XLO_CRYPT] = { - &none_funcs, - &xor_funcs -}; - -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 and the xloop - * needn't transform transfer. - * - * 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) && - mapping->a_ops->direct_IO && - !xlo->transfer) - 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 inline int -xlo_do_transfer(struct xloop_device *xlo, int cmd, - struct page *rpage, unsigned roffs, - struct page *lpage, unsigned loffs, - int size, sector_t rblock) -{ - int ret; - - ret = xlo->transfer(xlo, cmd, rpage, roffs, lpage, loffs, size, rblock); - if (likely(!ret)) - return 0; - - pr_err_ratelimited("Transfer error at byte offset %llu, length %i.\n", - (unsigned long long)rblock << 9, size); - return ret; -} - -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; - 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, DISK_EVENT_MEDIA_CHANGE); - 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); - return 0; - -out_err: - xloop_global_unlock(xlo, is_xloop); -out_putf: - fput(file); - return error; -} - -/* 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 += sprintf(buf + len, "\n"); - - return len; -} - -static ssize_t xloop_attr_offset_show(struct xloop_device *xlo, char *buf) -{ - return sprintf(buf, "%llu\n", (unsigned long long)xlo->xlo_offset); -} - -static ssize_t xloop_attr_sizelimit_show(struct xloop_device *xlo, char *buf) -{ - return sprintf(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 sprintf(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 sprintf(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 sprintf(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) && !xlo->xlo_encrypt_key_size) { - struct request_queue *backingq = bdev_get_queue(I_BDEV(inode)); - max_discard_sectors = backingq->limits.max_write_zeroes_sectors; - granularity = backingq->limits.discard_granularity ?: - queue_physical_block_size(backingq); - - /* - * We use punch hole to reclaim the free space used by the - * image a.k.a. discard. However we do not support discard if - * encryption is enabled, because it may give an attacker - * useful information. - */ - } else if (!file->f_op->fallocate || xlo->xlo_encrypt_key_size) { - max_discard_sectors = 0; - granularity = 0; - - } else { - max_discard_sectors = UINT_MAX >> 9; - granularity = inode->i_sb->s_blocksize; - } - - 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); - blk_queue_flag_set(QUEUE_FLAG_DISCARD, q); - } else { - q->limits.discard_granularity = 0; - blk_queue_max_discard_sectors(q, 0); - blk_queue_max_write_zeroes_sectors(q, 0); - blk_queue_flag_clear(QUEUE_FLAG_DISCARD, q); - } - q->limits.discard_alignment = 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); -static void xloop_rootcg_workfn(struct work_struct *work); -static void xloop_free_idle_workers(struct timer_list *timer); - -#ifdef CONFIG_BLK_CGROUP -static inline int queue_on_root_worker(struct cgroup_subsys_state *css) -{ - return !css || css == blkcg_root_css; -} +#if LINUX_VERSION_CODE < KERNEL_VERSION(5, 15, 0) +#include "xloop_main_4.18.c" #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 = &(xlo->worker_tree.rb_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_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 = blk_queue_nonrot(bdev_get_queue(file_bdev)); - - if (nonrot) - blk_queue_flag_set(QUEUE_FLAG_NONROT, q); - else - blk_queue_flag_clear(QUEUE_FLAG_NONROT, q); -} - -static int -xloop_release_xfer(struct xloop_device *xlo) -{ - int err = 0; - struct xloop_func_table *xfer = xlo->xlo_encryption; - - if (xfer) { - if (xfer->release) - err = xfer->release(xlo); - xlo->transfer = NULL; - xlo->xlo_encryption = NULL; - module_put(xfer->owner); - } - return err; -} - -static int -xloop_init_xfer(struct xloop_device *xlo, struct xloop_func_table *xfer, - const struct xloop_info64 *i) -{ - int err = 0; - - if (xfer) { - struct module *owner = xfer->owner; - - if (!try_module_get(owner)) - return -EINVAL; - if (xfer->init) - err = xfer->init(xlo, i); - if (err) - module_put(owner); - else - xlo->xlo_encryption = xfer; - } - return err; -} - -/** - * 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) -{ - int err; - struct xloop_func_table *xfer; - kuid_t uid = current_uid(); - - if ((unsigned int) info->xlo_encrypt_key_size > XLO_KEY_SIZE) - return -EINVAL; - - err = xloop_release_xfer(xlo); - if (err) - return err; - - if (info->xlo_encrypt_type) { - unsigned int type = info->xlo_encrypt_type; - - if (type >= MAX_XLO_CRYPT) - return -EINVAL; - xfer = xfer_funcs[type]; - if (xfer == NULL) - return -EINVAL; - } else - xfer = NULL; - - err = xloop_init_xfer(xlo, xfer, info); - if (err) - return err; - - xlo->xlo_offset = info->xlo_offset; - xlo->xlo_sizelimit = info->xlo_sizelimit; - memcpy(xlo->xlo_file_name, info->xlo_file_name, XLO_NAME_SIZE); - memcpy(xlo->xlo_crypt_name, info->xlo_crypt_name, XLO_NAME_SIZE); - xlo->xlo_file_name[XLO_NAME_SIZE-1] = 0; - xlo->xlo_crypt_name[XLO_NAME_SIZE-1] = 0; - - if (!xfer) - xfer = &none_funcs; - xlo->transfer = xfer->transfer; - xlo->ioctl = xfer->ioctl; - - xlo->xlo_flags = info->xlo_flags; - - xlo->xlo_encrypt_key_size = info->xlo_encrypt_key_size; - xlo->xlo_init[0] = info->xlo_init[0]; - xlo->xlo_init[1] = info->xlo_init[1]; - if (info->xlo_encrypt_key_size) { - memcpy(xlo->xlo_encrypt_key, info->xlo_encrypt_key, - info->xlo_encrypt_key_size); - xlo->xlo_key_owner = uid; - } - - return 0; -} - -static int xloop_configure(struct xloop_device *xlo, fmode_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 & FMODE_EXCL)) { - error = bd_prepare_to_claim(bdev, xloop_configure); - 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 & FMODE_WRITE) || - !file->f_op->write_iter) - xlo->xlo_flags |= XLO_FLAGS_READ_ONLY; - - xlo->workqueue = alloc_workqueue("xloop%d", - WQ_UNBOUND | WQ_FREEZABLE, - 0, - xlo->xlo_number); - if (!xlo->workqueue) { - error = -ENOMEM; - goto out_unlock; - } - - disk_force_media_change(xlo->xlo_disk, DISK_EVENT_MEDIA_CHANGE); - set_disk_ro(xlo->xlo_disk, (xlo->xlo_flags & XLO_FLAGS_READ_ONLY) != 0); - - INIT_WORK(&xlo->rootcg_work, xloop_rootcg_workfn); - INIT_LIST_HEAD(&xlo->rootcg_cmd_list); - INIT_LIST_HEAD(&xlo->idle_worker_list); - xlo->worker_tree = RB_ROOT; - timer_setup(&xlo->timer, xloop_free_idle_workers, - TIMER_DEFERRABLE); - 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) - 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) - xlo->xlo_disk->flags &= ~GENHD_FL_NO_PART_SCAN; - - xloop_global_unlock(xlo, is_xloop); - if (partscan) - xloop_reread_partitions(xlo); - if (!(mode & FMODE_EXCL)) - bd_abort_claiming(bdev, xloop_configure); - return 0; - -out_unlock: - xloop_global_unlock(xlo, is_xloop); -out_bdev: - if (!(mode & FMODE_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 int __xloop_clr_fd(struct xloop_device *xlo, bool release) -{ - struct file *filp = NULL; - gfp_t gfp = xlo->old_gfp_mask; - struct block_device *bdev = xlo->xlo_device; - int err = 0; - bool partscan = false; - int xlo_number; - struct xloop_worker *pos, *worker; - - /* - * Flush xloop_configure() and xloop_change_fd(). It is acceptable for - * xloop_validate_file() to succeed, for actual clear operation has not - * started yet. - */ - mutex_lock(&xloop_validate_mutex); - mutex_unlock(&xloop_validate_mutex); - /* - * xloop_validate_file() now fails because l->xlo_state != Xlo_bound - * became visible. - */ - - mutex_lock(&xlo->xlo_mutex); - if (WARN_ON_ONCE(xlo->xlo_state != Xlo_rundown)) { - err = -ENXIO; - goto out_unlock; - } - - filp = xlo->xlo_backing_file; - if (filp == NULL) { - err = -EINVAL; - goto out_unlock; - } - - if (test_bit(QUEUE_FLAG_WC, &xlo->xlo_queue->queue_flags)) - blk_queue_write_cache(xlo->xlo_queue, false, false); - - /* freeze request queue during the transition */ - blk_mq_freeze_queue(xlo->xlo_queue); - - xloop_file_fmt_exit(xlo->xlo_fmt); - - destroy_workqueue(xlo->workqueue); - spin_lock_irq(&xlo->xlo_work_lock); - list_for_each_entry_safe(worker, pos, &xlo->idle_worker_list, - idle_list) { - list_del(&worker->idle_list); - rb_erase(&worker->rb_node, &xlo->worker_tree); - css_put(worker->blkcg_css); - kfree(worker); - } - spin_unlock_irq(&xlo->xlo_work_lock); - del_timer_sync(&xlo->timer); - - spin_lock_irq(&xlo->xlo_lock); - xlo->xlo_backing_file = NULL; - spin_unlock_irq(&xlo->xlo_lock); - - xloop_release_xfer(xlo); - xlo->transfer = NULL; - xlo->ioctl = NULL; - xlo->xlo_device = NULL; - xlo->xlo_encryption = NULL; - xlo->xlo_offset = 0; - xlo->xlo_sizelimit = 0; - xlo->xlo_encrypt_key_size = 0; - memset(xlo->xlo_encrypt_key, 0, XLO_KEY_SIZE); - memset(xlo->xlo_crypt_name, 0, XLO_NAME_SIZE); - 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); - if (bdev) { - invalidate_bdev(bdev); - bdev->bd_inode->i_mapping->wb_err = 0; - } - set_capacity(xlo->xlo_disk, 0); - xloop_sysfs_exit(xlo); - if (bdev) { - /* let user-space know about this change */ - kobject_uevent(&disk_to_dev(bdev->bd_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); - blk_mq_unfreeze_queue(xlo->xlo_queue); - - partscan = xlo->xlo_flags & XLO_FLAGS_PARTSCAN && bdev; - xlo_number = xlo->xlo_number; - disk_force_media_change(xlo->xlo_disk, DISK_EVENT_MEDIA_CHANGE); -out_unlock: - mutex_unlock(&xlo->xlo_mutex); - if (partscan) { - /* - * 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) - dev_warn(xloop_device_to_dev(xlo), - "partition scan of xloop%d failed (rc=%d)\n", - xlo_number, err); - /* Device is gone, no point in returning error */ - err = 0; - } - - /* - * 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->xlo_backing_file is already cleared and Xlo_rundown state - * protects us from all the other places trying to change the 'xlo' - * device. - */ - mutex_lock(&xlo->xlo_mutex); - xlo->xlo_flags = 0; - if (!part_shift) - xlo->xlo_disk->flags |= GENHD_FL_NO_PART_SCAN; - 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. - */ - if (filp) - fput(filp); - return err; -} - -static int xloop_clr_fd(struct xloop_device *xlo) -{ - int err; - - err = mutex_lock_killable(&xlo->xlo_mutex); - if (err) - return err; - if (xlo->xlo_state != Xlo_bound) { - mutex_unlock(&xlo->xlo_mutex); - 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 (atomic_read(&xlo->xlo_refcnt) > 1) { - xlo->xlo_flags |= XLO_FLAGS_AUTOCLEAR; - mutex_unlock(&xlo->xlo_mutex); - return 0; - } - xlo->xlo_state = Xlo_rundown; - mutex_unlock(&xlo->xlo_mutex); - - return __xloop_clr_fd(xlo, false); -} - -static int -xloop_set_status(struct xloop_device *xlo, const struct xloop_info64 *info) -{ - int err; - kuid_t uid = current_uid(); - 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_encrypt_key_size && - !uid_eq(xlo->xlo_key_owner, uid) && - !capable(CAP_SYS_ADMIN)) { - err = -EPERM; - goto out_unlock; - } - 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); - - if (size_changed && xlo->xlo_device->bd_inode->i_mapping->nrpages) { - /* If any pages were dirtied after invalidate_bdev(), try again */ - err = -EAGAIN; - dev_warn(xloop_device_to_dev(xlo), - "xloop%d (%s) has still dirty pages (nrpages=%lu)\n", - xlo->xlo_number, xlo->xlo_file_name, - xlo->xlo_device->bd_inode->i_mapping->nrpages); - goto out_unfreeze; - } - - 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)) { - xlo->xlo_disk->flags &= ~GENHD_FL_NO_PART_SCAN; - 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); - memcpy(info->xlo_crypt_name, xlo->xlo_crypt_name, XLO_NAME_SIZE); - info->xlo_encrypt_type = - xlo->xlo_encryption ? xlo->xlo_encryption->number : 0; - if (xlo->xlo_encrypt_key_size && capable(CAP_SYS_ADMIN)) { - info->xlo_encrypt_key_size = xlo->xlo_encrypt_key_size; - memcpy(info->xlo_encrypt_key, xlo->xlo_encrypt_key, - xlo->xlo_encrypt_key_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_encrypt_type = info->xlo_encrypt_type; - info64->xlo_encrypt_key_size = info->xlo_encrypt_key_size; - info64->xlo_flags = info->xlo_flags; - info64->xlo_init[0] = info->xlo_init[0]; - info64->xlo_init[1] = info->xlo_init[1]; - if (info->xlo_encrypt_type == XLO_CRYPT_CRYPTOAPI) - memcpy(info64->xlo_crypt_name, info->xlo_name, XLO_NAME_SIZE); - else - memcpy(info64->xlo_file_name, info->xlo_name, XLO_NAME_SIZE); - memcpy(info64->xlo_encrypt_key, info->xlo_encrypt_key, XLO_KEY_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_encrypt_type = info64->xlo_encrypt_type; - info->xlo_encrypt_key_size = info64->xlo_encrypt_key_size; - info->xlo_flags = info64->xlo_flags; - info->xlo_init[0] = info64->xlo_init[0]; - info->xlo_init[1] = info64->xlo_init[1]; - if (info->xlo_encrypt_type == XLO_CRYPT_CRYPTOAPI) - memcpy(info->xlo_name, info64->xlo_crypt_name, XLO_NAME_SIZE); - else - memcpy(info->xlo_name, info64->xlo_file_name, XLO_NAME_SIZE); - memcpy(info->xlo_encrypt_key, info64->xlo_encrypt_key, XLO_KEY_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); - - /* invalidate_bdev should have truncated all the pages */ - if (xlo->xlo_device->bd_inode->i_mapping->nrpages) { - err = -EAGAIN; - dev_warn(xloop_device_to_dev(xlo), - "xloop%d (%s) has still dirty pages (nrpages=%lu)\n", - xlo->xlo_number, xlo->xlo_file_name, - xlo->xlo_device->bd_inode->i_mapping->nrpages); - goto out_unfreeze; - } - - 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); -out_unfreeze: - 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 = xlo->ioctl ? xlo->ioctl(xlo, cmd, arg) : -EINVAL; - } - mutex_unlock(&xlo->xlo_mutex); - return err; -} - -static int xlo_ioctl(struct block_device *bdev, fmode_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 & FMODE_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 & FMODE_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 & FMODE_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; - 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_encrypt_type = info.xlo_encrypt_type; - info64->xlo_encrypt_key_size = info.xlo_encrypt_key_size; - info64->xlo_flags = info.xlo_flags; - info64->xlo_init[0] = info.xlo_init[0]; - info64->xlo_init[1] = info.xlo_init[1]; - if (info.xlo_encrypt_type == XLO_CRYPT_CRYPTOAPI) - memcpy(info64->xlo_crypt_name, info.xlo_name, XLO_NAME_SIZE); - else - memcpy(info64->xlo_file_name, info.xlo_name, XLO_NAME_SIZE); - memcpy(info64->xlo_encrypt_key, info.xlo_encrypt_key, XLO_KEY_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_encrypt_type = info64->xlo_encrypt_type; - info.xlo_encrypt_key_size = info64->xlo_encrypt_key_size; - info.xlo_flags = info64->xlo_flags; - info.xlo_init[0] = info64->xlo_init[0]; - info.xlo_init[1] = info64->xlo_init[1]; - if (info.xlo_encrypt_type == XLO_CRYPT_CRYPTOAPI) - memcpy(info.xlo_name, info64->xlo_crypt_name, XLO_NAME_SIZE); - else - memcpy(info.xlo_name, info64->xlo_file_name, XLO_NAME_SIZE); - memcpy(info.xlo_encrypt_key, info64->xlo_encrypt_key, XLO_KEY_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 || - info.xlo_init[0] != info64->xlo_init[0] || - info.xlo_init[1] != info64->xlo_init[1]) - 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, fmode_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 int xlo_open(struct block_device *bdev, fmode_t mode) -{ - struct xloop_device *xlo = bdev->bd_disk->private_data; - int err; - - err = mutex_lock_killable(&xlo->xlo_mutex); - if (err) - return err; - if (xlo->xlo_state == Xlo_deleting) - err = -ENXIO; - else - atomic_inc(&xlo->xlo_refcnt); - mutex_unlock(&xlo->xlo_mutex); - return err; -} - -static void xlo_release(struct gendisk *disk, fmode_t mode) -{ - struct xloop_device *xlo = disk->private_data; - - mutex_lock(&xlo->xlo_mutex); - if (atomic_dec_return(&xlo->xlo_refcnt)) - goto out_unlock; - - if (xlo->xlo_flags & XLO_FLAGS_AUTOCLEAR) { - if (xlo->xlo_state != Xlo_bound) - goto out_unlock; - 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; - } else if (xlo->xlo_state == Xlo_bound) { - /* - * Otherwise keep thread (if running) and config, - * but flush possible ongoing bios in thread. - */ - blk_mq_freeze_queue(xlo->xlo_queue); - blk_mq_unfreeze_queue(xlo->xlo_queue); - } - -out_unlock: - mutex_unlock(&xlo->xlo_mutex); -} - -static const struct block_device_operations xlo_fops = { - .owner = THIS_MODULE, - .open = xlo_open, - .release = xlo_release, - .ioctl = xlo_ioctl, -#ifdef CONFIG_COMPAT - .compat_ioctl = xlo_compat_ioctl, -#endif -}; - -/* - * And now the modules code and kernel interface. - */ -static int max_xloop; -module_param(max_xloop, int, 0444); -MODULE_PARM_DESC(max_xloop, "Maximum number of xloop devices"); -module_param(max_part, int, 0444); -MODULE_PARM_DESC(max_part, "Maximum number of partitions per xloop device"); -MODULE_LICENSE("GPL"); -MODULE_AUTHOR("Manuel Bentele <development@manuel-bentele.de>"); -MODULE_VERSION(XLOOP_VERSION); -MODULE_ALIAS_BLOCKDEV_MAJOR(XLOOP_MAJOR); - -int xloop_register_transfer(struct xloop_func_table *funcs) -{ - unsigned int n = funcs->number; - - if (n >= MAX_XLO_CRYPT || xfer_funcs[n]) - return -EINVAL; - xfer_funcs[n] = funcs; - return 0; -} -EXPORT_SYMBOL(xloop_register_transfer); - -int xloop_unregister_transfer(int number) -{ - unsigned int n = number; - struct xloop_func_table *xfer = xfer_funcs[n]; - - if (n == 0 || n >= MAX_XLO_CRYPT || xfer == NULL) - return -EINVAL; - /* - * This function is called from only cleanup_cryptoxloop(). - * Given that each xloop device that has a transfer enabled holds a - * reference to the module implementing it we should never get here - * with a transfer that is set (unless forced module unloading is - * requested). Thus, check module's refcount and warn if this is - * not a clean unloading. - */ -#ifdef CONFIG_MODULE_UNLOAD - if (xfer->owner && module_refcount(xfer->owner) != -1) - pr_err("Danger! Unregistering an in use transfer function.\n"); -#endif - - xfer_funcs[n] = NULL; - return 0; -} -EXPORT_SYMBOL(xloop_unregister_transfer); - -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 && rq->bio->bi_blkg) { - cmd->blkcg_css = &bio_blkcg(rq->bio)->css; -#ifdef CONFIG_MEMCG - 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 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; - - 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)); - - 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 (!cmd->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_set_timer(struct xloop_device *xlo) -{ - timer_reduce(&xlo->timer, jiffies + XLOOP_IDLE_WORKER_TIMEOUT); -} - -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 void xloop_free_idle_workers(struct timer_list *timer) -{ - struct xloop_device *xlo = container_of(timer, struct xloop_device, timer); - 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 (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 const struct blk_mq_ops xloop_mq_ops = { - .queue_rq = xloop_queue_rq, - .complete = xlo_complete_rq, -}; - -static struct dentry *xloop_dbgfs_dir; - -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->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; - - err = -ENOMEM; - xlo->tag_set.ops = &xloop_mq_ops; - xlo->tag_set.nr_hw_queues = 1; - xlo->tag_set.queue_depth = 128; - 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) - disk->flags |= GENHD_FL_NO_PART_SCAN; - disk->flags |= GENHD_FL_EXT_DEVT; - atomic_set(&xlo->xlo_refcnt, 0); - mutex_init(&xlo->xlo_mutex); - xlo->xlo_number = i; - spin_lock_init(&xlo->xlo_lock); - spin_lock_init(&xlo->xlo_work_lock); - 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. */ - add_disk(disk); - /* 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: - blk_cleanup_disk(xlo->xlo_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); - debugfs_remove(xlo->xlo_dbgfs_dir); - /* Make this xloop device unreachable from pathname. */ - del_gendisk(xlo->xlo_disk); - blk_cleanup_disk(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); - /* There is no route which can find this xloop device. */ - mutex_destroy(&xlo->xlo_mutex); - kfree(xlo); -} - -static void xloop_probe(dev_t dev) -{ - int idx = MINOR(dev) >> part_shift; - - if (max_xloop && idx >= max_xloop) - return; - xloop_add(idx); -} - -static int xloop_control_remove(int idx) -{ - struct xloop_device *xlo; - int ret; - - if (idx < 0) { - pr_warn("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 || - atomic_read(&xlo->xlo_refcnt) > 0) { - mutex_unlock(&xlo->xlo_mutex); - ret = -EBUSY; - goto mark_visible; - } - /* Mark this xloop device no longer open()-able. */ - 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, nr; - 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; - } - - /* - * If max_xloop is specified, create that many devices upfront. - * This also becomes a hard limit. If max_xloop is not specified, - * create CONFIG_BLK_DEV_XLOOP_MIN_COUNT xloop devices at module - * init time. Loop devices can be requested on-demand with the - * /dev/xloop-control interface, or be instantiated by accessing - * a 'dead' device node. - */ - if (max_xloop) - nr = max_xloop; - else - nr = CONFIG_BLK_DEV_XLOOP_MIN_COUNT; - - 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 < nr; i++) - xloop_add(i); - - pr_info("module in 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); - return 1; -} - -__setup("max_xloop=", max_xloop_setup); +#include "xloop_main_5.15.c" #endif |