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1599 lines
37 KiB
1599 lines
37 KiB
// SPDX-License-Identifier: GPL-2.0 |
|
/* |
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* Copyright (C) 2018 Cambridge Greys Ltd |
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* Copyright (C) 2015-2016 Anton Ivanov ([email protected]) |
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* Copyright (C) 2000 Jeff Dike ([email protected]) |
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*/ |
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|
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/* 2001-09-28...2002-04-17 |
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* Partition stuff by [email protected] |
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* old style ubd by setting UBD_SHIFT to 0 |
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* 2002-09-27...2002-10-18 massive tinkering for 2.5 |
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* partitions have changed in 2.5 |
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* 2003-01-29 more tinkering for 2.5.59-1 |
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* This should now address the sysfs problems and has |
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* the symlink for devfs to allow for booting with |
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* the common /dev/ubd/discX/... names rather than |
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* only /dev/ubdN/discN this version also has lots of |
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* clean ups preparing for ubd-many. |
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* James McMechan |
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*/ |
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|
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#define UBD_SHIFT 4 |
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|
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#include <linux/module.h> |
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#include <linux/init.h> |
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#include <linux/blkdev.h> |
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#include <linux/blk-mq.h> |
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#include <linux/ata.h> |
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#include <linux/hdreg.h> |
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#include <linux/cdrom.h> |
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#include <linux/proc_fs.h> |
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#include <linux/seq_file.h> |
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#include <linux/ctype.h> |
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#include <linux/slab.h> |
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#include <linux/vmalloc.h> |
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#include <linux/platform_device.h> |
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#include <linux/scatterlist.h> |
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#include <asm/tlbflush.h> |
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#include <kern_util.h> |
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#include "mconsole_kern.h" |
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#include <init.h> |
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#include <irq_kern.h> |
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#include "ubd.h" |
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#include <os.h> |
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#include "cow.h" |
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|
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/* Max request size is determined by sector mask - 32K */ |
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#define UBD_MAX_REQUEST (8 * sizeof(long)) |
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|
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struct io_desc { |
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char *buffer; |
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unsigned long length; |
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unsigned long sector_mask; |
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unsigned long long cow_offset; |
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unsigned long bitmap_words[2]; |
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}; |
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|
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struct io_thread_req { |
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struct request *req; |
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int fds[2]; |
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unsigned long offsets[2]; |
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unsigned long long offset; |
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int sectorsize; |
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int error; |
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|
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int desc_cnt; |
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/* io_desc has to be the last element of the struct */ |
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struct io_desc io_desc[]; |
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}; |
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|
|
|
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static struct io_thread_req * (*irq_req_buffer)[]; |
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static struct io_thread_req *irq_remainder; |
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static int irq_remainder_size; |
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|
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static struct io_thread_req * (*io_req_buffer)[]; |
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static struct io_thread_req *io_remainder; |
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static int io_remainder_size; |
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|
|
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|
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static inline int ubd_test_bit(__u64 bit, unsigned char *data) |
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{ |
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__u64 n; |
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int bits, off; |
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|
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bits = sizeof(data[0]) * 8; |
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n = bit / bits; |
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off = bit % bits; |
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return (data[n] & (1 << off)) != 0; |
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} |
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|
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static inline void ubd_set_bit(__u64 bit, unsigned char *data) |
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{ |
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__u64 n; |
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int bits, off; |
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|
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bits = sizeof(data[0]) * 8; |
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n = bit / bits; |
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off = bit % bits; |
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data[n] |= (1 << off); |
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} |
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/*End stuff from ubd_user.h*/ |
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|
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#define DRIVER_NAME "uml-blkdev" |
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|
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static DEFINE_MUTEX(ubd_lock); |
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static DEFINE_MUTEX(ubd_mutex); /* replaces BKL, might not be needed */ |
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|
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static int ubd_open(struct block_device *bdev, fmode_t mode); |
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static void ubd_release(struct gendisk *disk, fmode_t mode); |
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static int ubd_ioctl(struct block_device *bdev, fmode_t mode, |
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unsigned int cmd, unsigned long arg); |
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static int ubd_getgeo(struct block_device *bdev, struct hd_geometry *geo); |
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|
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#define MAX_DEV (16) |
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|
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static const struct block_device_operations ubd_blops = { |
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.owner = THIS_MODULE, |
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.open = ubd_open, |
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.release = ubd_release, |
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.ioctl = ubd_ioctl, |
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.compat_ioctl = blkdev_compat_ptr_ioctl, |
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.getgeo = ubd_getgeo, |
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}; |
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|
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/* Protected by ubd_lock */ |
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static struct gendisk *ubd_gendisk[MAX_DEV]; |
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|
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#ifdef CONFIG_BLK_DEV_UBD_SYNC |
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#define OPEN_FLAGS ((struct openflags) { .r = 1, .w = 1, .s = 1, .c = 0, \ |
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.cl = 1 }) |
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#else |
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#define OPEN_FLAGS ((struct openflags) { .r = 1, .w = 1, .s = 0, .c = 0, \ |
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.cl = 1 }) |
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#endif |
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static struct openflags global_openflags = OPEN_FLAGS; |
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|
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struct cow { |
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/* backing file name */ |
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char *file; |
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/* backing file fd */ |
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int fd; |
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unsigned long *bitmap; |
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unsigned long bitmap_len; |
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int bitmap_offset; |
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int data_offset; |
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}; |
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|
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#define MAX_SG 64 |
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|
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struct ubd { |
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/* name (and fd, below) of the file opened for writing, either the |
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* backing or the cow file. */ |
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char *file; |
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char *serial; |
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int count; |
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int fd; |
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__u64 size; |
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struct openflags boot_openflags; |
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struct openflags openflags; |
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unsigned shared:1; |
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unsigned no_cow:1; |
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unsigned no_trim:1; |
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struct cow cow; |
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struct platform_device pdev; |
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struct request_queue *queue; |
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struct blk_mq_tag_set tag_set; |
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spinlock_t lock; |
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}; |
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|
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#define DEFAULT_COW { \ |
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.file = NULL, \ |
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.fd = -1, \ |
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.bitmap = NULL, \ |
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.bitmap_offset = 0, \ |
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.data_offset = 0, \ |
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} |
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|
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#define DEFAULT_UBD { \ |
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.file = NULL, \ |
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.serial = NULL, \ |
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.count = 0, \ |
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.fd = -1, \ |
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.size = -1, \ |
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.boot_openflags = OPEN_FLAGS, \ |
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.openflags = OPEN_FLAGS, \ |
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.no_cow = 0, \ |
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.no_trim = 0, \ |
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.shared = 0, \ |
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.cow = DEFAULT_COW, \ |
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.lock = __SPIN_LOCK_UNLOCKED(ubd_devs.lock), \ |
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} |
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|
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/* Protected by ubd_lock */ |
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static struct ubd ubd_devs[MAX_DEV] = { [0 ... MAX_DEV - 1] = DEFAULT_UBD }; |
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|
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static blk_status_t ubd_queue_rq(struct blk_mq_hw_ctx *hctx, |
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const struct blk_mq_queue_data *bd); |
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|
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static int fake_ide_setup(char *str) |
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{ |
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pr_warn("The fake_ide option has been removed\n"); |
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return 1; |
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} |
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__setup("fake_ide", fake_ide_setup); |
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|
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__uml_help(fake_ide_setup, |
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"fake_ide\n" |
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" Obsolete stub.\n\n" |
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); |
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|
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static int parse_unit(char **ptr) |
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{ |
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char *str = *ptr, *end; |
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int n = -1; |
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|
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if(isdigit(*str)) { |
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n = simple_strtoul(str, &end, 0); |
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if(end == str) |
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return -1; |
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*ptr = end; |
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} |
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else if (('a' <= *str) && (*str <= 'z')) { |
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n = *str - 'a'; |
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str++; |
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*ptr = str; |
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} |
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return n; |
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} |
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|
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/* If *index_out == -1 at exit, the passed option was a general one; |
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* otherwise, the str pointer is used (and owned) inside ubd_devs array, so it |
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* should not be freed on exit. |
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*/ |
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static int ubd_setup_common(char *str, int *index_out, char **error_out) |
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{ |
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struct ubd *ubd_dev; |
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struct openflags flags = global_openflags; |
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char *file, *backing_file, *serial; |
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int n, err = 0, i; |
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|
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if(index_out) *index_out = -1; |
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n = *str; |
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if(n == '='){ |
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str++; |
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if(!strcmp(str, "sync")){ |
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global_openflags = of_sync(global_openflags); |
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return err; |
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} |
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pr_warn("fake major not supported any more\n"); |
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return 0; |
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} |
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n = parse_unit(&str); |
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if(n < 0){ |
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*error_out = "Couldn't parse device number"; |
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return -EINVAL; |
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} |
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if(n >= MAX_DEV){ |
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*error_out = "Device number out of range"; |
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return 1; |
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} |
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err = -EBUSY; |
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mutex_lock(&ubd_lock); |
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|
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ubd_dev = &ubd_devs[n]; |
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if(ubd_dev->file != NULL){ |
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*error_out = "Device is already configured"; |
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goto out; |
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} |
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if (index_out) |
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*index_out = n; |
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err = -EINVAL; |
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for (i = 0; i < sizeof("rscdt="); i++) { |
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switch (*str) { |
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case 'r': |
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flags.w = 0; |
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break; |
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case 's': |
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flags.s = 1; |
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break; |
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case 'd': |
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ubd_dev->no_cow = 1; |
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break; |
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case 'c': |
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ubd_dev->shared = 1; |
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break; |
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case 't': |
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ubd_dev->no_trim = 1; |
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break; |
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case '=': |
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str++; |
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goto break_loop; |
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default: |
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*error_out = "Expected '=' or flag letter " |
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"(r, s, c, t or d)"; |
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goto out; |
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} |
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str++; |
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} |
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|
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if (*str == '=') |
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*error_out = "Too many flags specified"; |
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else |
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*error_out = "Missing '='"; |
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goto out; |
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|
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break_loop: |
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file = strsep(&str, ",:"); |
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if (*file == '\0') |
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file = NULL; |
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|
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backing_file = strsep(&str, ",:"); |
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if (backing_file && *backing_file == '\0') |
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backing_file = NULL; |
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serial = strsep(&str, ",:"); |
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if (serial && *serial == '\0') |
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serial = NULL; |
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|
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if (backing_file && ubd_dev->no_cow) { |
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*error_out = "Can't specify both 'd' and a cow file"; |
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goto out; |
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} |
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err = 0; |
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ubd_dev->file = file; |
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ubd_dev->cow.file = backing_file; |
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ubd_dev->serial = serial; |
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ubd_dev->boot_openflags = flags; |
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out: |
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mutex_unlock(&ubd_lock); |
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return err; |
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} |
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static int ubd_setup(char *str) |
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{ |
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char *error; |
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int err; |
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err = ubd_setup_common(str, NULL, &error); |
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if(err) |
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printk(KERN_ERR "Failed to initialize device with \"%s\" : " |
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"%s\n", str, error); |
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return 1; |
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} |
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__setup("ubd", ubd_setup); |
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__uml_help(ubd_setup, |
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"ubd<n><flags>=<filename>[(:|,)<filename2>][(:|,)<serial>]\n" |
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" This is used to associate a device with a file in the underlying\n" |
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" filesystem. When specifying two filenames, the first one is the\n" |
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" COW name and the second is the backing file name. As separator you can\n" |
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" use either a ':' or a ',': the first one allows writing things like;\n" |
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" ubd0=~/Uml/root_cow:~/Uml/root_backing_file\n" |
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" while with a ',' the shell would not expand the 2nd '~'.\n" |
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" When using only one filename, UML will detect whether to treat it like\n" |
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" a COW file or a backing file. To override this detection, add the 'd'\n" |
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" flag:\n" |
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" ubd0d=BackingFile\n" |
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" Usually, there is a filesystem in the file, but \n" |
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" that's not required. Swap devices containing swap files can be\n" |
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" specified like this. Also, a file which doesn't contain a\n" |
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" filesystem can have its contents read in the virtual \n" |
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" machine by running 'dd' on the device. <n> must be in the range\n" |
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" 0 to 7. Appending an 'r' to the number will cause that device\n" |
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" to be mounted read-only. For example ubd1r=./ext_fs. Appending\n" |
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" an 's' will cause data to be written to disk on the host immediately.\n" |
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" 'c' will cause the device to be treated as being shared between multiple\n" |
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" UMLs and file locking will be turned off - this is appropriate for a\n" |
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" cluster filesystem and inappropriate at almost all other times.\n\n" |
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" 't' will disable trim/discard support on the device (enabled by default).\n\n" |
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" An optional device serial number can be exposed using the serial parameter\n" |
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" on the cmdline which is exposed as a sysfs entry. This is particularly\n" |
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" useful when a unique number should be given to the device. Note when\n" |
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" specifying a label, the filename2 must be also presented. It can be\n" |
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" an empty string, in which case the backing file is not used:\n" |
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" ubd0=File,,Serial\n" |
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); |
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|
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static int udb_setup(char *str) |
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{ |
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printk("udb%s specified on command line is almost certainly a ubd -> " |
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"udb TYPO\n", str); |
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return 1; |
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} |
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|
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__setup("udb", udb_setup); |
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__uml_help(udb_setup, |
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"udb\n" |
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" This option is here solely to catch ubd -> udb typos, which can be\n" |
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" to impossible to catch visually unless you specifically look for\n" |
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" them. The only result of any option starting with 'udb' is an error\n" |
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" in the boot output.\n\n" |
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); |
|
|
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/* Only changed by ubd_init, which is an initcall. */ |
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static int thread_fd = -1; |
|
|
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/* Function to read several request pointers at a time |
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* handling fractional reads if (and as) needed |
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*/ |
|
|
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static int bulk_req_safe_read( |
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int fd, |
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struct io_thread_req * (*request_buffer)[], |
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struct io_thread_req **remainder, |
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int *remainder_size, |
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int max_recs |
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) |
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{ |
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int n = 0; |
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int res = 0; |
|
|
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if (*remainder_size > 0) { |
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memmove( |
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(char *) request_buffer, |
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(char *) remainder, *remainder_size |
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); |
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n = *remainder_size; |
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} |
|
|
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res = os_read_file( |
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fd, |
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((char *) request_buffer) + *remainder_size, |
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sizeof(struct io_thread_req *)*max_recs |
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- *remainder_size |
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); |
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if (res > 0) { |
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n += res; |
|
if ((n % sizeof(struct io_thread_req *)) > 0) { |
|
/* |
|
* Read somehow returned not a multiple of dword |
|
* theoretically possible, but never observed in the |
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* wild, so read routine must be able to handle it |
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*/ |
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*remainder_size = n % sizeof(struct io_thread_req *); |
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WARN(*remainder_size > 0, "UBD IPC read returned a partial result"); |
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memmove( |
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remainder, |
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((char *) request_buffer) + |
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(n/sizeof(struct io_thread_req *))*sizeof(struct io_thread_req *), |
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*remainder_size |
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); |
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n = n - *remainder_size; |
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} |
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} else { |
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n = res; |
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} |
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return n; |
|
} |
|
|
|
/* Called without dev->lock held, and only in interrupt context. */ |
|
static void ubd_handler(void) |
|
{ |
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int n; |
|
int count; |
|
|
|
while(1){ |
|
n = bulk_req_safe_read( |
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thread_fd, |
|
irq_req_buffer, |
|
&irq_remainder, |
|
&irq_remainder_size, |
|
UBD_REQ_BUFFER_SIZE |
|
); |
|
if (n < 0) { |
|
if(n == -EAGAIN) |
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break; |
|
printk(KERN_ERR "spurious interrupt in ubd_handler, " |
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"err = %d\n", -n); |
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return; |
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} |
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for (count = 0; count < n/sizeof(struct io_thread_req *); count++) { |
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struct io_thread_req *io_req = (*irq_req_buffer)[count]; |
|
|
|
if ((io_req->error == BLK_STS_NOTSUPP) && (req_op(io_req->req) == REQ_OP_DISCARD)) { |
|
blk_queue_max_discard_sectors(io_req->req->q, 0); |
|
blk_queue_max_write_zeroes_sectors(io_req->req->q, 0); |
|
blk_queue_flag_clear(QUEUE_FLAG_DISCARD, io_req->req->q); |
|
} |
|
blk_mq_end_request(io_req->req, io_req->error); |
|
kfree(io_req); |
|
} |
|
} |
|
} |
|
|
|
static irqreturn_t ubd_intr(int irq, void *dev) |
|
{ |
|
ubd_handler(); |
|
return IRQ_HANDLED; |
|
} |
|
|
|
/* Only changed by ubd_init, which is an initcall. */ |
|
static int io_pid = -1; |
|
|
|
static void kill_io_thread(void) |
|
{ |
|
if(io_pid != -1) |
|
os_kill_process(io_pid, 1); |
|
} |
|
|
|
__uml_exitcall(kill_io_thread); |
|
|
|
static inline int ubd_file_size(struct ubd *ubd_dev, __u64 *size_out) |
|
{ |
|
char *file; |
|
int fd; |
|
int err; |
|
|
|
__u32 version; |
|
__u32 align; |
|
char *backing_file; |
|
time64_t mtime; |
|
unsigned long long size; |
|
int sector_size; |
|
int bitmap_offset; |
|
|
|
if (ubd_dev->file && ubd_dev->cow.file) { |
|
file = ubd_dev->cow.file; |
|
|
|
goto out; |
|
} |
|
|
|
fd = os_open_file(ubd_dev->file, of_read(OPENFLAGS()), 0); |
|
if (fd < 0) |
|
return fd; |
|
|
|
err = read_cow_header(file_reader, &fd, &version, &backing_file, \ |
|
&mtime, &size, §or_size, &align, &bitmap_offset); |
|
os_close_file(fd); |
|
|
|
if(err == -EINVAL) |
|
file = ubd_dev->file; |
|
else |
|
file = backing_file; |
|
|
|
out: |
|
return os_file_size(file, size_out); |
|
} |
|
|
|
static int read_cow_bitmap(int fd, void *buf, int offset, int len) |
|
{ |
|
int err; |
|
|
|
err = os_pread_file(fd, buf, len, offset); |
|
if (err < 0) |
|
return err; |
|
|
|
return 0; |
|
} |
|
|
|
static int backing_file_mismatch(char *file, __u64 size, time64_t mtime) |
|
{ |
|
time64_t modtime; |
|
unsigned long long actual; |
|
int err; |
|
|
|
err = os_file_modtime(file, &modtime); |
|
if (err < 0) { |
|
printk(KERN_ERR "Failed to get modification time of backing " |
|
"file \"%s\", err = %d\n", file, -err); |
|
return err; |
|
} |
|
|
|
err = os_file_size(file, &actual); |
|
if (err < 0) { |
|
printk(KERN_ERR "Failed to get size of backing file \"%s\", " |
|
"err = %d\n", file, -err); |
|
return err; |
|
} |
|
|
|
if (actual != size) { |
|
/*__u64 can be a long on AMD64 and with %lu GCC complains; so |
|
* the typecast.*/ |
|
printk(KERN_ERR "Size mismatch (%llu vs %llu) of COW header " |
|
"vs backing file\n", (unsigned long long) size, actual); |
|
return -EINVAL; |
|
} |
|
if (modtime != mtime) { |
|
printk(KERN_ERR "mtime mismatch (%lld vs %lld) of COW header vs " |
|
"backing file\n", mtime, modtime); |
|
return -EINVAL; |
|
} |
|
return 0; |
|
} |
|
|
|
static int path_requires_switch(char *from_cmdline, char *from_cow, char *cow) |
|
{ |
|
struct uml_stat buf1, buf2; |
|
int err; |
|
|
|
if (from_cmdline == NULL) |
|
return 0; |
|
if (!strcmp(from_cmdline, from_cow)) |
|
return 0; |
|
|
|
err = os_stat_file(from_cmdline, &buf1); |
|
if (err < 0) { |
|
printk(KERN_ERR "Couldn't stat '%s', err = %d\n", from_cmdline, |
|
-err); |
|
return 0; |
|
} |
|
err = os_stat_file(from_cow, &buf2); |
|
if (err < 0) { |
|
printk(KERN_ERR "Couldn't stat '%s', err = %d\n", from_cow, |
|
-err); |
|
return 1; |
|
} |
|
if ((buf1.ust_dev == buf2.ust_dev) && (buf1.ust_ino == buf2.ust_ino)) |
|
return 0; |
|
|
|
printk(KERN_ERR "Backing file mismatch - \"%s\" requested, " |
|
"\"%s\" specified in COW header of \"%s\"\n", |
|
from_cmdline, from_cow, cow); |
|
return 1; |
|
} |
|
|
|
static int open_ubd_file(char *file, struct openflags *openflags, int shared, |
|
char **backing_file_out, int *bitmap_offset_out, |
|
unsigned long *bitmap_len_out, int *data_offset_out, |
|
int *create_cow_out) |
|
{ |
|
time64_t mtime; |
|
unsigned long long size; |
|
__u32 version, align; |
|
char *backing_file; |
|
int fd, err, sectorsize, asked_switch, mode = 0644; |
|
|
|
fd = os_open_file(file, *openflags, mode); |
|
if (fd < 0) { |
|
if ((fd == -ENOENT) && (create_cow_out != NULL)) |
|
*create_cow_out = 1; |
|
if (!openflags->w || |
|
((fd != -EROFS) && (fd != -EACCES))) |
|
return fd; |
|
openflags->w = 0; |
|
fd = os_open_file(file, *openflags, mode); |
|
if (fd < 0) |
|
return fd; |
|
} |
|
|
|
if (shared) |
|
printk(KERN_INFO "Not locking \"%s\" on the host\n", file); |
|
else { |
|
err = os_lock_file(fd, openflags->w); |
|
if (err < 0) { |
|
printk(KERN_ERR "Failed to lock '%s', err = %d\n", |
|
file, -err); |
|
goto out_close; |
|
} |
|
} |
|
|
|
/* Successful return case! */ |
|
if (backing_file_out == NULL) |
|
return fd; |
|
|
|
err = read_cow_header(file_reader, &fd, &version, &backing_file, &mtime, |
|
&size, §orsize, &align, bitmap_offset_out); |
|
if (err && (*backing_file_out != NULL)) { |
|
printk(KERN_ERR "Failed to read COW header from COW file " |
|
"\"%s\", errno = %d\n", file, -err); |
|
goto out_close; |
|
} |
|
if (err) |
|
return fd; |
|
|
|
asked_switch = path_requires_switch(*backing_file_out, backing_file, |
|
file); |
|
|
|
/* Allow switching only if no mismatch. */ |
|
if (asked_switch && !backing_file_mismatch(*backing_file_out, size, |
|
mtime)) { |
|
printk(KERN_ERR "Switching backing file to '%s'\n", |
|
*backing_file_out); |
|
err = write_cow_header(file, fd, *backing_file_out, |
|
sectorsize, align, &size); |
|
if (err) { |
|
printk(KERN_ERR "Switch failed, errno = %d\n", -err); |
|
goto out_close; |
|
} |
|
} else { |
|
*backing_file_out = backing_file; |
|
err = backing_file_mismatch(*backing_file_out, size, mtime); |
|
if (err) |
|
goto out_close; |
|
} |
|
|
|
cow_sizes(version, size, sectorsize, align, *bitmap_offset_out, |
|
bitmap_len_out, data_offset_out); |
|
|
|
return fd; |
|
out_close: |
|
os_close_file(fd); |
|
return err; |
|
} |
|
|
|
static int create_cow_file(char *cow_file, char *backing_file, |
|
struct openflags flags, |
|
int sectorsize, int alignment, int *bitmap_offset_out, |
|
unsigned long *bitmap_len_out, int *data_offset_out) |
|
{ |
|
int err, fd; |
|
|
|
flags.c = 1; |
|
fd = open_ubd_file(cow_file, &flags, 0, NULL, NULL, NULL, NULL, NULL); |
|
if (fd < 0) { |
|
err = fd; |
|
printk(KERN_ERR "Open of COW file '%s' failed, errno = %d\n", |
|
cow_file, -err); |
|
goto out; |
|
} |
|
|
|
err = init_cow_file(fd, cow_file, backing_file, sectorsize, alignment, |
|
bitmap_offset_out, bitmap_len_out, |
|
data_offset_out); |
|
if (!err) |
|
return fd; |
|
os_close_file(fd); |
|
out: |
|
return err; |
|
} |
|
|
|
static void ubd_close_dev(struct ubd *ubd_dev) |
|
{ |
|
os_close_file(ubd_dev->fd); |
|
if(ubd_dev->cow.file == NULL) |
|
return; |
|
|
|
os_close_file(ubd_dev->cow.fd); |
|
vfree(ubd_dev->cow.bitmap); |
|
ubd_dev->cow.bitmap = NULL; |
|
} |
|
|
|
static int ubd_open_dev(struct ubd *ubd_dev) |
|
{ |
|
struct openflags flags; |
|
char **back_ptr; |
|
int err, create_cow, *create_ptr; |
|
int fd; |
|
|
|
ubd_dev->openflags = ubd_dev->boot_openflags; |
|
create_cow = 0; |
|
create_ptr = (ubd_dev->cow.file != NULL) ? &create_cow : NULL; |
|
back_ptr = ubd_dev->no_cow ? NULL : &ubd_dev->cow.file; |
|
|
|
fd = open_ubd_file(ubd_dev->file, &ubd_dev->openflags, ubd_dev->shared, |
|
back_ptr, &ubd_dev->cow.bitmap_offset, |
|
&ubd_dev->cow.bitmap_len, &ubd_dev->cow.data_offset, |
|
create_ptr); |
|
|
|
if((fd == -ENOENT) && create_cow){ |
|
fd = create_cow_file(ubd_dev->file, ubd_dev->cow.file, |
|
ubd_dev->openflags, SECTOR_SIZE, PAGE_SIZE, |
|
&ubd_dev->cow.bitmap_offset, |
|
&ubd_dev->cow.bitmap_len, |
|
&ubd_dev->cow.data_offset); |
|
if(fd >= 0){ |
|
printk(KERN_INFO "Creating \"%s\" as COW file for " |
|
"\"%s\"\n", ubd_dev->file, ubd_dev->cow.file); |
|
} |
|
} |
|
|
|
if(fd < 0){ |
|
printk("Failed to open '%s', errno = %d\n", ubd_dev->file, |
|
-fd); |
|
return fd; |
|
} |
|
ubd_dev->fd = fd; |
|
|
|
if(ubd_dev->cow.file != NULL){ |
|
blk_queue_max_hw_sectors(ubd_dev->queue, 8 * sizeof(long)); |
|
|
|
err = -ENOMEM; |
|
ubd_dev->cow.bitmap = vmalloc(ubd_dev->cow.bitmap_len); |
|
if(ubd_dev->cow.bitmap == NULL){ |
|
printk(KERN_ERR "Failed to vmalloc COW bitmap\n"); |
|
goto error; |
|
} |
|
flush_tlb_kernel_vm(); |
|
|
|
err = read_cow_bitmap(ubd_dev->fd, ubd_dev->cow.bitmap, |
|
ubd_dev->cow.bitmap_offset, |
|
ubd_dev->cow.bitmap_len); |
|
if(err < 0) |
|
goto error; |
|
|
|
flags = ubd_dev->openflags; |
|
flags.w = 0; |
|
err = open_ubd_file(ubd_dev->cow.file, &flags, ubd_dev->shared, NULL, |
|
NULL, NULL, NULL, NULL); |
|
if(err < 0) goto error; |
|
ubd_dev->cow.fd = err; |
|
} |
|
if (ubd_dev->no_trim == 0) { |
|
ubd_dev->queue->limits.discard_granularity = SECTOR_SIZE; |
|
ubd_dev->queue->limits.discard_alignment = SECTOR_SIZE; |
|
blk_queue_max_discard_sectors(ubd_dev->queue, UBD_MAX_REQUEST); |
|
blk_queue_max_write_zeroes_sectors(ubd_dev->queue, UBD_MAX_REQUEST); |
|
blk_queue_flag_set(QUEUE_FLAG_DISCARD, ubd_dev->queue); |
|
} |
|
blk_queue_flag_set(QUEUE_FLAG_NONROT, ubd_dev->queue); |
|
return 0; |
|
error: |
|
os_close_file(ubd_dev->fd); |
|
return err; |
|
} |
|
|
|
static void ubd_device_release(struct device *dev) |
|
{ |
|
struct ubd *ubd_dev = dev_get_drvdata(dev); |
|
|
|
blk_mq_free_tag_set(&ubd_dev->tag_set); |
|
*ubd_dev = ((struct ubd) DEFAULT_UBD); |
|
} |
|
|
|
static ssize_t serial_show(struct device *dev, |
|
struct device_attribute *attr, char *buf) |
|
{ |
|
struct gendisk *disk = dev_to_disk(dev); |
|
struct ubd *ubd_dev = disk->private_data; |
|
|
|
if (!ubd_dev) |
|
return 0; |
|
|
|
return sprintf(buf, "%s", ubd_dev->serial); |
|
} |
|
|
|
static DEVICE_ATTR_RO(serial); |
|
|
|
static struct attribute *ubd_attrs[] = { |
|
&dev_attr_serial.attr, |
|
NULL, |
|
}; |
|
|
|
static umode_t ubd_attrs_are_visible(struct kobject *kobj, |
|
struct attribute *a, int n) |
|
{ |
|
return a->mode; |
|
} |
|
|
|
static const struct attribute_group ubd_attr_group = { |
|
.attrs = ubd_attrs, |
|
.is_visible = ubd_attrs_are_visible, |
|
}; |
|
|
|
static const struct attribute_group *ubd_attr_groups[] = { |
|
&ubd_attr_group, |
|
NULL, |
|
}; |
|
|
|
static void ubd_disk_register(int major, u64 size, int unit, |
|
struct gendisk *disk) |
|
{ |
|
disk->major = major; |
|
disk->first_minor = unit << UBD_SHIFT; |
|
disk->minors = 1 << UBD_SHIFT; |
|
disk->fops = &ubd_blops; |
|
set_capacity(disk, size / 512); |
|
sprintf(disk->disk_name, "ubd%c", 'a' + unit); |
|
|
|
ubd_devs[unit].pdev.id = unit; |
|
ubd_devs[unit].pdev.name = DRIVER_NAME; |
|
ubd_devs[unit].pdev.dev.release = ubd_device_release; |
|
dev_set_drvdata(&ubd_devs[unit].pdev.dev, &ubd_devs[unit]); |
|
platform_device_register(&ubd_devs[unit].pdev); |
|
|
|
disk->private_data = &ubd_devs[unit]; |
|
disk->queue = ubd_devs[unit].queue; |
|
device_add_disk(&ubd_devs[unit].pdev.dev, disk, ubd_attr_groups); |
|
} |
|
|
|
#define ROUND_BLOCK(n) ((n + (SECTOR_SIZE - 1)) & (-SECTOR_SIZE)) |
|
|
|
static const struct blk_mq_ops ubd_mq_ops = { |
|
.queue_rq = ubd_queue_rq, |
|
}; |
|
|
|
static int ubd_add(int n, char **error_out) |
|
{ |
|
struct ubd *ubd_dev = &ubd_devs[n]; |
|
struct gendisk *disk; |
|
int err = 0; |
|
|
|
if(ubd_dev->file == NULL) |
|
goto out; |
|
|
|
err = ubd_file_size(ubd_dev, &ubd_dev->size); |
|
if(err < 0){ |
|
*error_out = "Couldn't determine size of device's file"; |
|
goto out; |
|
} |
|
|
|
ubd_dev->size = ROUND_BLOCK(ubd_dev->size); |
|
|
|
ubd_dev->tag_set.ops = &ubd_mq_ops; |
|
ubd_dev->tag_set.queue_depth = 64; |
|
ubd_dev->tag_set.numa_node = NUMA_NO_NODE; |
|
ubd_dev->tag_set.flags = BLK_MQ_F_SHOULD_MERGE; |
|
ubd_dev->tag_set.driver_data = ubd_dev; |
|
ubd_dev->tag_set.nr_hw_queues = 1; |
|
|
|
err = blk_mq_alloc_tag_set(&ubd_dev->tag_set); |
|
if (err) |
|
goto out; |
|
|
|
disk = blk_mq_alloc_disk(&ubd_dev->tag_set, ubd_dev); |
|
if (IS_ERR(disk)) { |
|
err = PTR_ERR(disk); |
|
goto out_cleanup_tags; |
|
} |
|
ubd_dev->queue = disk->queue; |
|
|
|
blk_queue_write_cache(ubd_dev->queue, true, false); |
|
blk_queue_max_segments(ubd_dev->queue, MAX_SG); |
|
blk_queue_segment_boundary(ubd_dev->queue, PAGE_SIZE - 1); |
|
ubd_disk_register(UBD_MAJOR, ubd_dev->size, n, disk); |
|
ubd_gendisk[n] = disk; |
|
return 0; |
|
|
|
out_cleanup_tags: |
|
blk_mq_free_tag_set(&ubd_dev->tag_set); |
|
out: |
|
return err; |
|
} |
|
|
|
static int ubd_config(char *str, char **error_out) |
|
{ |
|
int n, ret; |
|
|
|
/* This string is possibly broken up and stored, so it's only |
|
* freed if ubd_setup_common fails, or if only general options |
|
* were set. |
|
*/ |
|
str = kstrdup(str, GFP_KERNEL); |
|
if (str == NULL) { |
|
*error_out = "Failed to allocate memory"; |
|
return -ENOMEM; |
|
} |
|
|
|
ret = ubd_setup_common(str, &n, error_out); |
|
if (ret) |
|
goto err_free; |
|
|
|
if (n == -1) { |
|
ret = 0; |
|
goto err_free; |
|
} |
|
|
|
mutex_lock(&ubd_lock); |
|
ret = ubd_add(n, error_out); |
|
if (ret) |
|
ubd_devs[n].file = NULL; |
|
mutex_unlock(&ubd_lock); |
|
|
|
out: |
|
return ret; |
|
|
|
err_free: |
|
kfree(str); |
|
goto out; |
|
} |
|
|
|
static int ubd_get_config(char *name, char *str, int size, char **error_out) |
|
{ |
|
struct ubd *ubd_dev; |
|
int n, len = 0; |
|
|
|
n = parse_unit(&name); |
|
if((n >= MAX_DEV) || (n < 0)){ |
|
*error_out = "ubd_get_config : device number out of range"; |
|
return -1; |
|
} |
|
|
|
ubd_dev = &ubd_devs[n]; |
|
mutex_lock(&ubd_lock); |
|
|
|
if(ubd_dev->file == NULL){ |
|
CONFIG_CHUNK(str, size, len, "", 1); |
|
goto out; |
|
} |
|
|
|
CONFIG_CHUNK(str, size, len, ubd_dev->file, 0); |
|
|
|
if(ubd_dev->cow.file != NULL){ |
|
CONFIG_CHUNK(str, size, len, ",", 0); |
|
CONFIG_CHUNK(str, size, len, ubd_dev->cow.file, 1); |
|
} |
|
else CONFIG_CHUNK(str, size, len, "", 1); |
|
|
|
out: |
|
mutex_unlock(&ubd_lock); |
|
return len; |
|
} |
|
|
|
static int ubd_id(char **str, int *start_out, int *end_out) |
|
{ |
|
int n; |
|
|
|
n = parse_unit(str); |
|
*start_out = 0; |
|
*end_out = MAX_DEV - 1; |
|
return n; |
|
} |
|
|
|
static int ubd_remove(int n, char **error_out) |
|
{ |
|
struct gendisk *disk = ubd_gendisk[n]; |
|
struct ubd *ubd_dev; |
|
int err = -ENODEV; |
|
|
|
mutex_lock(&ubd_lock); |
|
|
|
ubd_dev = &ubd_devs[n]; |
|
|
|
if(ubd_dev->file == NULL) |
|
goto out; |
|
|
|
/* you cannot remove a open disk */ |
|
err = -EBUSY; |
|
if(ubd_dev->count > 0) |
|
goto out; |
|
|
|
ubd_gendisk[n] = NULL; |
|
if(disk != NULL){ |
|
del_gendisk(disk); |
|
blk_cleanup_disk(disk); |
|
} |
|
|
|
err = 0; |
|
platform_device_unregister(&ubd_dev->pdev); |
|
out: |
|
mutex_unlock(&ubd_lock); |
|
return err; |
|
} |
|
|
|
/* All these are called by mconsole in process context and without |
|
* ubd-specific locks. The structure itself is const except for .list. |
|
*/ |
|
static struct mc_device ubd_mc = { |
|
.list = LIST_HEAD_INIT(ubd_mc.list), |
|
.name = "ubd", |
|
.config = ubd_config, |
|
.get_config = ubd_get_config, |
|
.id = ubd_id, |
|
.remove = ubd_remove, |
|
}; |
|
|
|
static int __init ubd_mc_init(void) |
|
{ |
|
mconsole_register_dev(&ubd_mc); |
|
return 0; |
|
} |
|
|
|
__initcall(ubd_mc_init); |
|
|
|
static int __init ubd0_init(void) |
|
{ |
|
struct ubd *ubd_dev = &ubd_devs[0]; |
|
|
|
mutex_lock(&ubd_lock); |
|
if(ubd_dev->file == NULL) |
|
ubd_dev->file = "root_fs"; |
|
mutex_unlock(&ubd_lock); |
|
|
|
return 0; |
|
} |
|
|
|
__initcall(ubd0_init); |
|
|
|
/* Used in ubd_init, which is an initcall */ |
|
static struct platform_driver ubd_driver = { |
|
.driver = { |
|
.name = DRIVER_NAME, |
|
}, |
|
}; |
|
|
|
static int __init ubd_init(void) |
|
{ |
|
char *error; |
|
int i, err; |
|
|
|
if (register_blkdev(UBD_MAJOR, "ubd")) |
|
return -1; |
|
|
|
irq_req_buffer = kmalloc_array(UBD_REQ_BUFFER_SIZE, |
|
sizeof(struct io_thread_req *), |
|
GFP_KERNEL |
|
); |
|
irq_remainder = 0; |
|
|
|
if (irq_req_buffer == NULL) { |
|
printk(KERN_ERR "Failed to initialize ubd buffering\n"); |
|
return -1; |
|
} |
|
io_req_buffer = kmalloc_array(UBD_REQ_BUFFER_SIZE, |
|
sizeof(struct io_thread_req *), |
|
GFP_KERNEL |
|
); |
|
|
|
io_remainder = 0; |
|
|
|
if (io_req_buffer == NULL) { |
|
printk(KERN_ERR "Failed to initialize ubd buffering\n"); |
|
return -1; |
|
} |
|
platform_driver_register(&ubd_driver); |
|
mutex_lock(&ubd_lock); |
|
for (i = 0; i < MAX_DEV; i++){ |
|
err = ubd_add(i, &error); |
|
if(err) |
|
printk(KERN_ERR "Failed to initialize ubd device %d :" |
|
"%s\n", i, error); |
|
} |
|
mutex_unlock(&ubd_lock); |
|
return 0; |
|
} |
|
|
|
late_initcall(ubd_init); |
|
|
|
static int __init ubd_driver_init(void){ |
|
unsigned long stack; |
|
int err; |
|
|
|
/* Set by CONFIG_BLK_DEV_UBD_SYNC or ubd=sync.*/ |
|
if(global_openflags.s){ |
|
printk(KERN_INFO "ubd: Synchronous mode\n"); |
|
/* Letting ubd=sync be like using ubd#s= instead of ubd#= is |
|
* enough. So use anyway the io thread. */ |
|
} |
|
stack = alloc_stack(0, 0); |
|
io_pid = start_io_thread(stack + PAGE_SIZE, &thread_fd); |
|
if(io_pid < 0){ |
|
printk(KERN_ERR |
|
"ubd : Failed to start I/O thread (errno = %d) - " |
|
"falling back to synchronous I/O\n", -io_pid); |
|
io_pid = -1; |
|
return 0; |
|
} |
|
err = um_request_irq(UBD_IRQ, thread_fd, IRQ_READ, ubd_intr, |
|
0, "ubd", ubd_devs); |
|
if(err < 0) |
|
printk(KERN_ERR "um_request_irq failed - errno = %d\n", -err); |
|
return 0; |
|
} |
|
|
|
device_initcall(ubd_driver_init); |
|
|
|
static int ubd_open(struct block_device *bdev, fmode_t mode) |
|
{ |
|
struct gendisk *disk = bdev->bd_disk; |
|
struct ubd *ubd_dev = disk->private_data; |
|
int err = 0; |
|
|
|
mutex_lock(&ubd_mutex); |
|
if(ubd_dev->count == 0){ |
|
err = ubd_open_dev(ubd_dev); |
|
if(err){ |
|
printk(KERN_ERR "%s: Can't open \"%s\": errno = %d\n", |
|
disk->disk_name, ubd_dev->file, -err); |
|
goto out; |
|
} |
|
} |
|
ubd_dev->count++; |
|
set_disk_ro(disk, !ubd_dev->openflags.w); |
|
|
|
/* This should no more be needed. And it didn't work anyway to exclude |
|
* read-write remounting of filesystems.*/ |
|
/*if((mode & FMODE_WRITE) && !ubd_dev->openflags.w){ |
|
if(--ubd_dev->count == 0) ubd_close_dev(ubd_dev); |
|
err = -EROFS; |
|
}*/ |
|
out: |
|
mutex_unlock(&ubd_mutex); |
|
return err; |
|
} |
|
|
|
static void ubd_release(struct gendisk *disk, fmode_t mode) |
|
{ |
|
struct ubd *ubd_dev = disk->private_data; |
|
|
|
mutex_lock(&ubd_mutex); |
|
if(--ubd_dev->count == 0) |
|
ubd_close_dev(ubd_dev); |
|
mutex_unlock(&ubd_mutex); |
|
} |
|
|
|
static void cowify_bitmap(__u64 io_offset, int length, unsigned long *cow_mask, |
|
__u64 *cow_offset, unsigned long *bitmap, |
|
__u64 bitmap_offset, unsigned long *bitmap_words, |
|
__u64 bitmap_len) |
|
{ |
|
__u64 sector = io_offset >> SECTOR_SHIFT; |
|
int i, update_bitmap = 0; |
|
|
|
for (i = 0; i < length >> SECTOR_SHIFT; i++) { |
|
if(cow_mask != NULL) |
|
ubd_set_bit(i, (unsigned char *) cow_mask); |
|
if(ubd_test_bit(sector + i, (unsigned char *) bitmap)) |
|
continue; |
|
|
|
update_bitmap = 1; |
|
ubd_set_bit(sector + i, (unsigned char *) bitmap); |
|
} |
|
|
|
if(!update_bitmap) |
|
return; |
|
|
|
*cow_offset = sector / (sizeof(unsigned long) * 8); |
|
|
|
/* This takes care of the case where we're exactly at the end of the |
|
* device, and *cow_offset + 1 is off the end. So, just back it up |
|
* by one word. Thanks to Lynn Kerby for the fix and James McMechan |
|
* for the original diagnosis. |
|
*/ |
|
if (*cow_offset == (DIV_ROUND_UP(bitmap_len, |
|
sizeof(unsigned long)) - 1)) |
|
(*cow_offset)--; |
|
|
|
bitmap_words[0] = bitmap[*cow_offset]; |
|
bitmap_words[1] = bitmap[*cow_offset + 1]; |
|
|
|
*cow_offset *= sizeof(unsigned long); |
|
*cow_offset += bitmap_offset; |
|
} |
|
|
|
static void cowify_req(struct io_thread_req *req, struct io_desc *segment, |
|
unsigned long offset, unsigned long *bitmap, |
|
__u64 bitmap_offset, __u64 bitmap_len) |
|
{ |
|
__u64 sector = offset >> SECTOR_SHIFT; |
|
int i; |
|
|
|
if (segment->length > (sizeof(segment->sector_mask) * 8) << SECTOR_SHIFT) |
|
panic("Operation too long"); |
|
|
|
if (req_op(req->req) == REQ_OP_READ) { |
|
for (i = 0; i < segment->length >> SECTOR_SHIFT; i++) { |
|
if(ubd_test_bit(sector + i, (unsigned char *) bitmap)) |
|
ubd_set_bit(i, (unsigned char *) |
|
&segment->sector_mask); |
|
} |
|
} else { |
|
cowify_bitmap(offset, segment->length, &segment->sector_mask, |
|
&segment->cow_offset, bitmap, bitmap_offset, |
|
segment->bitmap_words, bitmap_len); |
|
} |
|
} |
|
|
|
static void ubd_map_req(struct ubd *dev, struct io_thread_req *io_req, |
|
struct request *req) |
|
{ |
|
struct bio_vec bvec; |
|
struct req_iterator iter; |
|
int i = 0; |
|
unsigned long byte_offset = io_req->offset; |
|
int op = req_op(req); |
|
|
|
if (op == REQ_OP_WRITE_ZEROES || op == REQ_OP_DISCARD) { |
|
io_req->io_desc[0].buffer = NULL; |
|
io_req->io_desc[0].length = blk_rq_bytes(req); |
|
} else { |
|
rq_for_each_segment(bvec, req, iter) { |
|
BUG_ON(i >= io_req->desc_cnt); |
|
|
|
io_req->io_desc[i].buffer = |
|
page_address(bvec.bv_page) + bvec.bv_offset; |
|
io_req->io_desc[i].length = bvec.bv_len; |
|
i++; |
|
} |
|
} |
|
|
|
if (dev->cow.file) { |
|
for (i = 0; i < io_req->desc_cnt; i++) { |
|
cowify_req(io_req, &io_req->io_desc[i], byte_offset, |
|
dev->cow.bitmap, dev->cow.bitmap_offset, |
|
dev->cow.bitmap_len); |
|
byte_offset += io_req->io_desc[i].length; |
|
} |
|
|
|
} |
|
} |
|
|
|
static struct io_thread_req *ubd_alloc_req(struct ubd *dev, struct request *req, |
|
int desc_cnt) |
|
{ |
|
struct io_thread_req *io_req; |
|
int i; |
|
|
|
io_req = kmalloc(sizeof(*io_req) + |
|
(desc_cnt * sizeof(struct io_desc)), |
|
GFP_ATOMIC); |
|
if (!io_req) |
|
return NULL; |
|
|
|
io_req->req = req; |
|
if (dev->cow.file) |
|
io_req->fds[0] = dev->cow.fd; |
|
else |
|
io_req->fds[0] = dev->fd; |
|
io_req->error = 0; |
|
io_req->sectorsize = SECTOR_SIZE; |
|
io_req->fds[1] = dev->fd; |
|
io_req->offset = (u64) blk_rq_pos(req) << SECTOR_SHIFT; |
|
io_req->offsets[0] = 0; |
|
io_req->offsets[1] = dev->cow.data_offset; |
|
|
|
for (i = 0 ; i < desc_cnt; i++) { |
|
io_req->io_desc[i].sector_mask = 0; |
|
io_req->io_desc[i].cow_offset = -1; |
|
} |
|
|
|
return io_req; |
|
} |
|
|
|
static int ubd_submit_request(struct ubd *dev, struct request *req) |
|
{ |
|
int segs = 0; |
|
struct io_thread_req *io_req; |
|
int ret; |
|
int op = req_op(req); |
|
|
|
if (op == REQ_OP_FLUSH) |
|
segs = 0; |
|
else if (op == REQ_OP_WRITE_ZEROES || op == REQ_OP_DISCARD) |
|
segs = 1; |
|
else |
|
segs = blk_rq_nr_phys_segments(req); |
|
|
|
io_req = ubd_alloc_req(dev, req, segs); |
|
if (!io_req) |
|
return -ENOMEM; |
|
|
|
io_req->desc_cnt = segs; |
|
if (segs) |
|
ubd_map_req(dev, io_req, req); |
|
|
|
ret = os_write_file(thread_fd, &io_req, sizeof(io_req)); |
|
if (ret != sizeof(io_req)) { |
|
if (ret != -EAGAIN) |
|
pr_err("write to io thread failed: %d\n", -ret); |
|
kfree(io_req); |
|
} |
|
return ret; |
|
} |
|
|
|
static blk_status_t ubd_queue_rq(struct blk_mq_hw_ctx *hctx, |
|
const struct blk_mq_queue_data *bd) |
|
{ |
|
struct ubd *ubd_dev = hctx->queue->queuedata; |
|
struct request *req = bd->rq; |
|
int ret = 0, res = BLK_STS_OK; |
|
|
|
blk_mq_start_request(req); |
|
|
|
spin_lock_irq(&ubd_dev->lock); |
|
|
|
switch (req_op(req)) { |
|
case REQ_OP_FLUSH: |
|
case REQ_OP_READ: |
|
case REQ_OP_WRITE: |
|
case REQ_OP_DISCARD: |
|
case REQ_OP_WRITE_ZEROES: |
|
ret = ubd_submit_request(ubd_dev, req); |
|
break; |
|
default: |
|
WARN_ON_ONCE(1); |
|
res = BLK_STS_NOTSUPP; |
|
} |
|
|
|
spin_unlock_irq(&ubd_dev->lock); |
|
|
|
if (ret < 0) { |
|
if (ret == -ENOMEM) |
|
res = BLK_STS_RESOURCE; |
|
else |
|
res = BLK_STS_DEV_RESOURCE; |
|
} |
|
|
|
return res; |
|
} |
|
|
|
static int ubd_getgeo(struct block_device *bdev, struct hd_geometry *geo) |
|
{ |
|
struct ubd *ubd_dev = bdev->bd_disk->private_data; |
|
|
|
geo->heads = 128; |
|
geo->sectors = 32; |
|
geo->cylinders = ubd_dev->size / (128 * 32 * 512); |
|
return 0; |
|
} |
|
|
|
static int ubd_ioctl(struct block_device *bdev, fmode_t mode, |
|
unsigned int cmd, unsigned long arg) |
|
{ |
|
struct ubd *ubd_dev = bdev->bd_disk->private_data; |
|
u16 ubd_id[ATA_ID_WORDS]; |
|
|
|
switch (cmd) { |
|
struct cdrom_volctrl volume; |
|
case HDIO_GET_IDENTITY: |
|
memset(&ubd_id, 0, ATA_ID_WORDS * 2); |
|
ubd_id[ATA_ID_CYLS] = ubd_dev->size / (128 * 32 * 512); |
|
ubd_id[ATA_ID_HEADS] = 128; |
|
ubd_id[ATA_ID_SECTORS] = 32; |
|
if(copy_to_user((char __user *) arg, (char *) &ubd_id, |
|
sizeof(ubd_id))) |
|
return -EFAULT; |
|
return 0; |
|
|
|
case CDROMVOLREAD: |
|
if(copy_from_user(&volume, (char __user *) arg, sizeof(volume))) |
|
return -EFAULT; |
|
volume.channel0 = 255; |
|
volume.channel1 = 255; |
|
volume.channel2 = 255; |
|
volume.channel3 = 255; |
|
if(copy_to_user((char __user *) arg, &volume, sizeof(volume))) |
|
return -EFAULT; |
|
return 0; |
|
} |
|
return -EINVAL; |
|
} |
|
|
|
static int map_error(int error_code) |
|
{ |
|
switch (error_code) { |
|
case 0: |
|
return BLK_STS_OK; |
|
case ENOSYS: |
|
case EOPNOTSUPP: |
|
return BLK_STS_NOTSUPP; |
|
case ENOSPC: |
|
return BLK_STS_NOSPC; |
|
} |
|
return BLK_STS_IOERR; |
|
} |
|
|
|
/* |
|
* Everything from here onwards *IS NOT PART OF THE KERNEL* |
|
* |
|
* The following functions are part of UML hypervisor code. |
|
* All functions from here onwards are executed as a helper |
|
* thread and are not allowed to execute any kernel functions. |
|
* |
|
* Any communication must occur strictly via shared memory and IPC. |
|
* |
|
* Do not add printks, locks, kernel memory operations, etc - it |
|
* will result in unpredictable behaviour and/or crashes. |
|
*/ |
|
|
|
static int update_bitmap(struct io_thread_req *req, struct io_desc *segment) |
|
{ |
|
int n; |
|
|
|
if (segment->cow_offset == -1) |
|
return map_error(0); |
|
|
|
n = os_pwrite_file(req->fds[1], &segment->bitmap_words, |
|
sizeof(segment->bitmap_words), segment->cow_offset); |
|
if (n != sizeof(segment->bitmap_words)) |
|
return map_error(-n); |
|
|
|
return map_error(0); |
|
} |
|
|
|
static void do_io(struct io_thread_req *req, struct io_desc *desc) |
|
{ |
|
char *buf = NULL; |
|
unsigned long len; |
|
int n, nsectors, start, end, bit; |
|
__u64 off; |
|
|
|
/* FLUSH is really a special case, we cannot "case" it with others */ |
|
|
|
if (req_op(req->req) == REQ_OP_FLUSH) { |
|
/* fds[0] is always either the rw image or our cow file */ |
|
req->error = map_error(-os_sync_file(req->fds[0])); |
|
return; |
|
} |
|
|
|
nsectors = desc->length / req->sectorsize; |
|
start = 0; |
|
do { |
|
bit = ubd_test_bit(start, (unsigned char *) &desc->sector_mask); |
|
end = start; |
|
while((end < nsectors) && |
|
(ubd_test_bit(end, (unsigned char *) &desc->sector_mask) == bit)) |
|
end++; |
|
|
|
off = req->offset + req->offsets[bit] + |
|
start * req->sectorsize; |
|
len = (end - start) * req->sectorsize; |
|
if (desc->buffer != NULL) |
|
buf = &desc->buffer[start * req->sectorsize]; |
|
|
|
switch (req_op(req->req)) { |
|
case REQ_OP_READ: |
|
n = 0; |
|
do { |
|
buf = &buf[n]; |
|
len -= n; |
|
n = os_pread_file(req->fds[bit], buf, len, off); |
|
if (n < 0) { |
|
req->error = map_error(-n); |
|
return; |
|
} |
|
} while((n < len) && (n != 0)); |
|
if (n < len) memset(&buf[n], 0, len - n); |
|
break; |
|
case REQ_OP_WRITE: |
|
n = os_pwrite_file(req->fds[bit], buf, len, off); |
|
if(n != len){ |
|
req->error = map_error(-n); |
|
return; |
|
} |
|
break; |
|
case REQ_OP_DISCARD: |
|
case REQ_OP_WRITE_ZEROES: |
|
n = os_falloc_punch(req->fds[bit], off, len); |
|
if (n) { |
|
req->error = map_error(-n); |
|
return; |
|
} |
|
break; |
|
default: |
|
WARN_ON_ONCE(1); |
|
req->error = BLK_STS_NOTSUPP; |
|
return; |
|
} |
|
|
|
start = end; |
|
} while(start < nsectors); |
|
|
|
req->offset += len; |
|
req->error = update_bitmap(req, desc); |
|
} |
|
|
|
/* Changed in start_io_thread, which is serialized by being called only |
|
* from ubd_init, which is an initcall. |
|
*/ |
|
int kernel_fd = -1; |
|
|
|
/* Only changed by the io thread. XXX: currently unused. */ |
|
static int io_count = 0; |
|
|
|
int io_thread(void *arg) |
|
{ |
|
int n, count, written, res; |
|
|
|
os_fix_helper_signals(); |
|
|
|
while(1){ |
|
n = bulk_req_safe_read( |
|
kernel_fd, |
|
io_req_buffer, |
|
&io_remainder, |
|
&io_remainder_size, |
|
UBD_REQ_BUFFER_SIZE |
|
); |
|
if (n <= 0) { |
|
if (n == -EAGAIN) |
|
ubd_read_poll(-1); |
|
|
|
continue; |
|
} |
|
|
|
for (count = 0; count < n/sizeof(struct io_thread_req *); count++) { |
|
struct io_thread_req *req = (*io_req_buffer)[count]; |
|
int i; |
|
|
|
io_count++; |
|
for (i = 0; !req->error && i < req->desc_cnt; i++) |
|
do_io(req, &(req->io_desc[i])); |
|
|
|
} |
|
|
|
written = 0; |
|
|
|
do { |
|
res = os_write_file(kernel_fd, |
|
((char *) io_req_buffer) + written, |
|
n - written); |
|
if (res >= 0) { |
|
written += res; |
|
} |
|
if (written < n) { |
|
ubd_write_poll(-1); |
|
} |
|
} while (written < n); |
|
} |
|
|
|
return 0; |
|
}
|
|
|