+++ /dev/null
-/* -*- mode: c; c-basic-offset: 8; indent-tabs-mode: nil; -*-
- * vim:expandtab:shiftwidth=8:tabstop=8:
- *
- * Lustre virtual block device emulator.
- *
- * Copyright (c) 2001-2003 Cluster File Systems, Inc.
- *
- * This file is part of Lustre, http://www.lustre.org.
- *
- * Lustre is free software; you can redistribute it and/or
- * modify it under the terms of version 2 of the GNU General Public
- * License as published by the Free Software Foundation.
- *
- * Lustre is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with Lustre; if not, write to the Free Software
- * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
- */
-
-/*
- * linux/drivers/block/loop.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_loop_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 loop devices now dynamic via max_loop module parameter.
- * Russell Kroll <rkroll@exploits.org> 19990701
- *
- * Maximum number of loop devices when compiled-in now selectable by passing
- * max_loop=<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 loop devices
- * Heinz Mauelshagen <mge@sistina.com>, Feb 2002
- *
- * Support for falling back on the write file operation when the address space
- * operations prepare_write and/or commit_write are not available on the
- * backing filesystem.
- * Anton Altaparmakov, 16 Feb 2005
- *
- * Still To Fix:
- * - Advisory locking is ignored here.
- * - Should use an own CAP_* category instead of CAP_SYS_ADMIN
- *
- */
-
-#include <linux/config.h>
-#include <linux/module.h>
-
-#include <linux/sched.h>
-#include <linux/fs.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/smp_lock.h>
-#include <linux/swap.h>
-#include <linux/slab.h>
-#include <linux/suspend.h>
-#include <linux/writeback.h>
-#include <linux/buffer_head.h> /* for invalidate_bdev() */
-#include <linux/completion.h>
-#include <linux/highmem.h>
-#include <linux/gfp.h>
-#include <linux/swap.h>
-#include <linux/pagevec.h>
-
-#include <asm/uaccess.h>
-
-#include <lustre_lib.h>
-#include <lustre_lite.h>
-#include "llite_internal.h"
-
-#define LLOOP_MAX_SEGMENTS PTLRPC_MAX_BRW_PAGES
-
-/* Possible states of device */
-enum {
- LLOOP_UNBOUND,
- LLOOP_BOUND,
- LLOOP_RUNDOWN,
-};
-
-struct lloop_device {
- int lo_number;
- int lo_refcnt;
- loff_t lo_offset;
- loff_t lo_sizelimit;
- int lo_flags;
- int (*ioctl)(struct lloop_device *, int cmd,
- unsigned long arg);
-
- struct file * lo_backing_file;
- struct block_device *lo_device;
- unsigned lo_blocksize;
-
- int old_gfp_mask;
-
- spinlock_t lo_lock;
- struct bio *lo_bio;
- struct bio *lo_biotail;
- int lo_state;
- struct semaphore lo_sem;
- struct semaphore lo_ctl_mutex;
- struct semaphore lo_bh_mutex;
- atomic_t lo_pending;
-
- request_queue_t *lo_queue;
-
- /* data to handle bio for lustre. */
- struct lo_request_data {
- struct brw_page lrd_pages[LLOOP_MAX_SEGMENTS];
- struct obdo lrd_oa;
- } lo_requests[1];
-
-};
-
-/*
- * Loop flags
- */
-enum {
- LO_FLAGS_READ_ONLY = 1,
-};
-
-static int lloop_major;
-static int max_loop = 8;
-static struct lloop_device *loop_dev;
-static struct gendisk **disks;
-static struct semaphore lloop_mutex;
-static void *ll_iocontrol_magic = NULL;
-
-static loff_t get_loop_size(struct lloop_device *lo, struct file *file)
-{
- loff_t size, offset, loopsize;
-
- /* Compute loopsize in bytes */
- size = i_size_read(file->f_mapping->host);
- offset = lo->lo_offset;
- loopsize = size - offset;
- if (lo->lo_sizelimit > 0 && lo->lo_sizelimit < loopsize)
- loopsize = lo->lo_sizelimit;
-
- /*
- * Unfortunately, if we want to do I/O on the device,
- * the number of 512-byte sectors has to fit into a sector_t.
- */
- return loopsize >> 9;
-}
-
-static int do_bio_filebacked(struct lloop_device *lo, struct bio *bio)
-{
- struct inode *inode = lo->lo_backing_file->f_dentry->d_inode;
- struct ll_inode_info *lli = ll_i2info(inode);
- struct lov_stripe_md *lsm = lli->lli_smd;
- struct obd_info oinfo = {{{0}}};
- struct brw_page *pg = lo->lo_requests[0].lrd_pages;
- struct obdo *oa = &lo->lo_requests[0].lrd_oa;
- pgoff_t offset;
- int ret, cmd, i;
- struct bio_vec *bvec;
-
- BUG_ON(bio->bi_hw_segments > LLOOP_MAX_SEGMENTS);
-
- offset = (pgoff_t)(bio->bi_sector << 9) + lo->lo_offset;
- bio_for_each_segment(bvec, bio, i) {
- BUG_ON(bvec->bv_offset != 0);
- BUG_ON(bvec->bv_len != CFS_PAGE_SIZE);
-
- pg->pg = bvec->bv_page;
- pg->off = offset;
- pg->count = bvec->bv_len;
- pg->flag = OBD_BRW_SRVLOCK;
-
- pg++;
- offset += bvec->bv_len;
- }
-
- oa->o_mode = inode->i_mode;
- oa->o_id = lsm->lsm_object_id;
- oa->o_valid = OBD_MD_FLID | OBD_MD_FLMODE | OBD_MD_FLTYPE;
- obdo_from_inode(oa, inode, OBD_MD_FLFID | OBD_MD_FLGENER);
-
- cmd = OBD_BRW_READ;
- if (bio_rw(bio) == WRITE)
- cmd = OBD_BRW_WRITE;
-
- if (cmd == OBD_BRW_WRITE)
- ll_stats_ops_tally(ll_i2sbi(inode), LPROC_LL_BRW_WRITE, bio->bi_size);
- else
- ll_stats_ops_tally(ll_i2sbi(inode), LPROC_LL_BRW_READ, bio->bi_size);
- oinfo.oi_oa = oa;
- oinfo.oi_md = lsm;
- ret = obd_brw(cmd, ll_i2obdexp(inode), &oinfo,
- (obd_count)(i - bio->bi_idx),
- lo->lo_requests[0].lrd_pages, NULL);
- if (ret == 0)
- obdo_to_inode(inode, oa, OBD_MD_FLBLOCKS);
- return ret;
-}
-
-
-/*
- * Add bio to back of pending list
- */
-static void loop_add_bio(struct lloop_device *lo, struct bio *bio)
-{
- unsigned long flags;
-
- spin_lock_irqsave(&lo->lo_lock, flags);
- if (lo->lo_biotail) {
- lo->lo_biotail->bi_next = bio;
- lo->lo_biotail = bio;
- } else
- lo->lo_bio = lo->lo_biotail = bio;
- spin_unlock_irqrestore(&lo->lo_lock, flags);
-
- up(&lo->lo_bh_mutex);
-}
-
-/*
- * Grab first pending buffer
- */
-static struct bio *loop_get_bio(struct lloop_device *lo)
-{
- struct bio *bio;
-
- spin_lock_irq(&lo->lo_lock);
- if ((bio = lo->lo_bio)) {
- if (bio == lo->lo_biotail)
- lo->lo_biotail = NULL;
- lo->lo_bio = bio->bi_next;
- bio->bi_next = NULL;
- }
- spin_unlock_irq(&lo->lo_lock);
-
- return bio;
-}
-
-static int loop_make_request(request_queue_t *q, struct bio *old_bio)
-{
- struct lloop_device *lo = q->queuedata;
- int rw = bio_rw(old_bio);
-
- if (!lo)
- goto out;
-
- spin_lock_irq(&lo->lo_lock);
- if (lo->lo_state != LLOOP_BOUND)
- goto inactive;
- atomic_inc(&lo->lo_pending);
- spin_unlock_irq(&lo->lo_lock);
-
- if (rw == WRITE) {
- if (lo->lo_flags & LO_FLAGS_READ_ONLY)
- goto err;
- } else if (rw == READA) {
- rw = READ;
- } else if (rw != READ) {
- CERROR("lloop: unknown command (%x)\n", rw);
- goto err;
- }
- loop_add_bio(lo, old_bio);
- return 0;
-err:
- if (atomic_dec_and_test(&lo->lo_pending))
- up(&lo->lo_bh_mutex);
-out:
- bio_io_error(old_bio, old_bio->bi_size);
- return 0;
-inactive:
- spin_unlock_irq(&lo->lo_lock);
- goto out;
-}
-
-/*
- * kick off io on the underlying address space
- */
-static void loop_unplug(request_queue_t *q)
-{
- struct lloop_device *lo = q->queuedata;
-
- clear_bit(QUEUE_FLAG_PLUGGED, &q->queue_flags);
- blk_run_address_space(lo->lo_backing_file->f_mapping);
-}
-
-static inline void loop_handle_bio(struct lloop_device *lo, struct bio *bio)
-{
- int ret;
- ret = do_bio_filebacked(lo, bio);
- bio_endio(bio, bio->bi_size, ret);
-}
-
-/*
- * worker thread that handles reads/writes to file backed loop devices,
- * to avoid blocking in our make_request_fn. it also does loop decrypting
- * on reads for block backed loop, as that is too heavy to do from
- * b_end_io context where irqs may be disabled.
- */
-static int loop_thread(void *data)
-{
- struct lloop_device *lo = data;
- struct bio *bio;
-
- daemonize("lloop%d", lo->lo_number);
-
- set_user_nice(current, -20);
-
- lo->lo_state = LLOOP_BOUND;
- atomic_inc(&lo->lo_pending);
-
- /*
- * up sem, we are running
- */
- up(&lo->lo_sem);
-
- for (;;) {
- down_interruptible(&lo->lo_bh_mutex);
- /*
- * could be upped because of tear-down, not because of
- * pending work
- */
- if (!atomic_read(&lo->lo_pending))
- break;
-
- bio = loop_get_bio(lo);
- if (!bio) {
- CWARN("lloop(minor: %d): missing bio\n", lo->lo_number);
- continue;
- }
- loop_handle_bio(lo, bio);
-
- /*
- * upped both for pending work and tear-down, lo_pending
- * will hit zero then
- */
- if (atomic_dec_and_test(&lo->lo_pending))
- break;
- }
-
- up(&lo->lo_sem);
- return 0;
-}
-
-static int loop_set_fd(struct lloop_device *lo, struct file *unused,
- struct block_device *bdev, struct file *file)
-{
- struct inode *inode;
- struct address_space *mapping;
- int lo_flags = 0;
- int error;
- loff_t size;
-
- if (!try_module_get(THIS_MODULE))
- return -ENODEV;
-
- error = -EBUSY;
- if (lo->lo_state != LLOOP_UNBOUND)
- goto out;
-
- mapping = file->f_mapping;
- inode = mapping->host;
-
- error = -EINVAL;
- if (!S_ISREG(inode->i_mode) || inode->i_sb->s_magic != LL_SUPER_MAGIC)
- goto out;
-
- if (!(file->f_mode & FMODE_WRITE))
- lo_flags |= LO_FLAGS_READ_ONLY;
-
- size = get_loop_size(lo, file);
-
- if ((loff_t)(sector_t)size != size) {
- error = -EFBIG;
- goto out;
- }
-
- /* remove all pages in cache so as dirty pages not to be existent. */
- truncate_inode_pages(mapping, 0);
-
- set_device_ro(bdev, (lo_flags & LO_FLAGS_READ_ONLY) != 0);
-
- lo->lo_blocksize = CFS_PAGE_SIZE;
- lo->lo_device = bdev;
- lo->lo_flags = lo_flags;
- lo->lo_backing_file = file;
- lo->ioctl = NULL;
- lo->lo_sizelimit = 0;
- lo->old_gfp_mask = mapping_gfp_mask(mapping);
- mapping_set_gfp_mask(mapping, lo->old_gfp_mask & ~(__GFP_IO|__GFP_FS));
-
- lo->lo_bio = lo->lo_biotail = NULL;
-
- /*
- * set queue make_request_fn, and add limits based on lower level
- * device
- */
- blk_queue_make_request(lo->lo_queue, loop_make_request);
- lo->lo_queue->queuedata = lo;
- lo->lo_queue->unplug_fn = loop_unplug;
-
- /* queue parameters */
- blk_queue_hardsect_size(lo->lo_queue, CFS_PAGE_SIZE);
- blk_queue_max_sectors(lo->lo_queue, LLOOP_MAX_SEGMENTS);
- blk_queue_max_phys_segments(lo->lo_queue, LLOOP_MAX_SEGMENTS);
-
- set_capacity(disks[lo->lo_number], size);
- bd_set_size(bdev, size << 9);
-
- set_blocksize(bdev, lo->lo_blocksize);
-
- kernel_thread(loop_thread, lo, CLONE_KERNEL);
- down(&lo->lo_sem);
- return 0;
-
- out:
- /* This is safe: open() is still holding a reference. */
- module_put(THIS_MODULE);
- return error;
-}
-
-static int loop_clr_fd(struct lloop_device *lo, struct block_device *bdev,
- int count)
-{
- struct file *filp = lo->lo_backing_file;
- int gfp = lo->old_gfp_mask;
-
- if (lo->lo_state != LLOOP_BOUND)
- return -ENXIO;
-
- if (lo->lo_refcnt > count) /* we needed one fd for the ioctl */
- return -EBUSY;
-
- if (filp == NULL)
- return -EINVAL;
-
- spin_lock_irq(&lo->lo_lock);
- lo->lo_state = LLOOP_RUNDOWN;
- if (atomic_dec_and_test(&lo->lo_pending))
- up(&lo->lo_bh_mutex);
- spin_unlock_irq(&lo->lo_lock);
-
- down(&lo->lo_sem);
- lo->lo_backing_file = NULL;
- lo->ioctl = NULL;
- lo->lo_device = NULL;
- lo->lo_offset = 0;
- lo->lo_sizelimit = 0;
- lo->lo_flags = 0;
- invalidate_bdev(bdev, 0);
- set_capacity(disks[lo->lo_number], 0);
- bd_set_size(bdev, 0);
- mapping_set_gfp_mask(filp->f_mapping, gfp);
- lo->lo_state = LLOOP_UNBOUND;
- fput(filp);
- /* This is safe: open() is still holding a reference. */
- module_put(THIS_MODULE);
- return 0;
-}
-
-static int lo_open(struct inode *inode, struct file *file)
-{
- struct lloop_device *lo = inode->i_bdev->bd_disk->private_data;
-
- down(&lo->lo_ctl_mutex);
- lo->lo_refcnt++;
- up(&lo->lo_ctl_mutex);
-
- return 0;
-}
-
-static int lo_release(struct inode *inode, struct file *file)
-{
- struct lloop_device *lo = inode->i_bdev->bd_disk->private_data;
-
- down(&lo->lo_ctl_mutex);
- --lo->lo_refcnt;
- up(&lo->lo_ctl_mutex);
-
- return 0;
-}
-
-/* lloop device node's ioctl function. */
-static int lo_ioctl(struct inode *inode, struct file *unused,
- unsigned int cmd, unsigned long arg)
-{
- struct lloop_device *lo = inode->i_bdev->bd_disk->private_data;
- struct block_device *bdev = inode->i_bdev;
- int err = 0;
-
- down(&lloop_mutex);
- switch (cmd) {
- case LL_IOC_LLOOP_DETACH: {
- err = loop_clr_fd(lo, bdev, 2);
- if (err == 0)
- blkdev_put(bdev); /* grabbed in LLOOP_ATTACH */
- break;
- }
-
- case LL_IOC_LLOOP_INFO: {
- __u64 ino = 0;
-
- if (lo->lo_state == LLOOP_BOUND)
- ino = lo->lo_backing_file->f_dentry->d_inode->i_ino;
-
- if (put_user(ino, (__u64 *)arg))
- err = -EFAULT;
- break;
- }
-
- default:
- err = -EINVAL;
- break;
- }
- up(&lloop_mutex);
-
- return err;
-}
-
-static struct block_device_operations lo_fops = {
- .owner = THIS_MODULE,
- .open = lo_open,
- .release = lo_release,
- .ioctl = lo_ioctl,
-};
-
-/* dynamic iocontrol callback.
- * This callback is registered in lloop_init and will be called by
- * ll_iocontrol_call.
- * This is a llite regular file ioctl function. It takes the responsibility
- * of attaching a file, and detaching a file by a lloop's device numner.
- */
-static enum llioc_iter lloop_ioctl(struct inode *unused, struct file *file,
- unsigned int cmd, unsigned long arg,
- void *magic, int *rcp)
-{
- struct lloop_device *lo = NULL;
- struct block_device *bdev = NULL;
- int err = 0;
- dev_t dev;
-
- if (magic != ll_iocontrol_magic)
- return LLIOC_CONT;
-
- if (disks == NULL)
- GOTO(out1, err = -ENODEV);
-
- down(&lloop_mutex);
- switch (cmd) {
- case LL_IOC_LLOOP_ATTACH: {
- struct lloop_device *lo_free = NULL;
- int i;
-
- for (i = 0; i < max_loop; i++, lo = NULL) {
- lo = &loop_dev[i];
- if (lo->lo_state == LLOOP_UNBOUND) {
- if (!lo_free)
- lo_free = lo;
- continue;
- }
- if (lo->lo_backing_file->f_dentry->d_inode ==
- file->f_dentry->d_inode)
- break;
- }
- if (lo || !lo_free)
- GOTO(out, err = -EBUSY);
-
- lo = lo_free;
- dev = MKDEV(lloop_major, lo->lo_number);
-
- /* quit if the used pointer is writable */
- if (put_user((long)old_encode_dev(dev), (long*)arg))
- GOTO(out, err = -EFAULT);
-
- bdev = open_by_devnum(dev, file->f_mode);
- if (IS_ERR(bdev))
- GOTO(out, err = PTR_ERR(bdev));
-
- get_file(file);
- err = loop_set_fd(lo, NULL, bdev, file);
- if (err) {
- fput(file);
- blkdev_put(bdev);
- }
-
- break;
- }
-
- case LL_IOC_LLOOP_DETACH_BYDEV: {
- int minor;
-
- dev = old_decode_dev(arg);
- if (MAJOR(dev) != lloop_major)
- GOTO(out, err = -EINVAL);
-
- minor = MINOR(dev);
- if (minor > max_loop - 1)
- GOTO(out, err = -EINVAL);
-
- lo = &loop_dev[minor];
- if (lo->lo_state != LLOOP_BOUND)
- GOTO(out, err = -EINVAL);
-
- bdev = lo->lo_device;
- err = loop_clr_fd(lo, bdev, 1);
- if (err == 0)
- blkdev_put(bdev); /* grabbed in LLOOP_ATTACH */
-
- break;
- }
-
- default:
- err = -EINVAL;
- break;
- }
-
-out:
- up(&lloop_mutex);
-out1:
- if (rcp)
- *rcp = err;
- return LLIOC_STOP;
-}
-
-static int __init lloop_init(void)
-{
- int i;
- unsigned int cmdlist[] = {
- LL_IOC_LLOOP_ATTACH,
- LL_IOC_LLOOP_DETACH_BYDEV,
- };
-
- if (max_loop < 1 || max_loop > 256) {
- CWARN("lloop: invalid max_loop (must be between"
- " 1 and 256), using default (8)\n");
- max_loop = 8;
- }
-
- lloop_major = register_blkdev(0, "lloop");
- if (lloop_major < 0)
- return -EIO;
-
- ll_iocontrol_magic = ll_iocontrol_register(lloop_ioctl, 2, cmdlist);
- if (ll_iocontrol_magic == NULL)
- goto out_mem1;
-
- loop_dev = kmalloc(max_loop * sizeof(struct lloop_device), GFP_KERNEL);
- if (!loop_dev)
- goto out_mem1;
- memset(loop_dev, 0, max_loop * sizeof(struct lloop_device));
-
- disks = kmalloc(max_loop * sizeof(struct gendisk *), GFP_KERNEL);
- if (!disks)
- goto out_mem2;
-
- for (i = 0; i < max_loop; i++) {
- disks[i] = alloc_disk(1);
- if (!disks[i])
- goto out_mem3;
- }
-
- init_MUTEX(&lloop_mutex);
-
- for (i = 0; i < max_loop; i++) {
- struct lloop_device *lo = &loop_dev[i];
- struct gendisk *disk = disks[i];
-
- memset(lo, 0, sizeof(*lo));
- lo->lo_queue = blk_alloc_queue(GFP_KERNEL);
- if (!lo->lo_queue)
- goto out_mem4;
-
- init_MUTEX(&lo->lo_ctl_mutex);
- init_MUTEX_LOCKED(&lo->lo_sem);
- init_MUTEX_LOCKED(&lo->lo_bh_mutex);
- lo->lo_number = i;
- spin_lock_init(&lo->lo_lock);
- disk->major = lloop_major;
- disk->first_minor = i;
- disk->fops = &lo_fops;
- sprintf(disk->disk_name, "lloop%d", i);
- disk->private_data = lo;
- disk->queue = lo->lo_queue;
- }
-
- /* We cannot fail after we call this, so another loop!*/
- for (i = 0; i < max_loop; i++)
- add_disk(disks[i]);
- return 0;
-
-out_mem4:
- while (i--)
- blk_put_queue(loop_dev[i].lo_queue);
- i = max_loop;
-out_mem3:
- while (i--)
- put_disk(disks[i]);
- kfree(disks);
-out_mem2:
- kfree(loop_dev);
-out_mem1:
- unregister_blkdev(lloop_major, "lloop");
- ll_iocontrol_unregister(ll_iocontrol_magic);
- CERROR("lloop: ran out of memory\n");
- return -ENOMEM;
-}
-
-static void lloop_exit(void)
-{
- int i;
-
- ll_iocontrol_unregister(ll_iocontrol_magic);
- for (i = 0; i < max_loop; i++) {
- del_gendisk(disks[i]);
- blk_put_queue(loop_dev[i].lo_queue);
- put_disk(disks[i]);
- }
- if (unregister_blkdev(lloop_major, "lloop"))
- CWARN("lloop: cannot unregister blkdev\n");
-
- kfree(disks);
- kfree(loop_dev);
-}
-
-module_init(lloop_init);
-module_exit(lloop_exit);
-
-CFS_MODULE_PARM(max_loop, "i", int, 0444, "maximum of lloop_device");
git://git.whamcloud.com / fs / lustre-release.git / commitdiff