119 lines
3.3 KiB
C
119 lines
3.3 KiB
C
/******************************************************************************
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* blkback/vbd.c
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*
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* Routines for managing virtual block devices (VBDs).
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*
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* Copyright (c) 2003-2005, Keir Fraser & Steve Hand
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License version 2
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* as published by the Free Software Foundation; or, when distributed
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* separately from the Linux kernel or incorporated into other
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* software packages, subject to the following license:
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this source file (the "Software"), to deal in the Software without
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* restriction, including without limitation the rights to use, copy, modify,
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* merge, publish, distribute, sublicense, and/or sell copies of the Software,
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* and to permit persons to whom the Software is furnished to do so, subject to
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* the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
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* IN THE SOFTWARE.
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*/
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#include "common.h"
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#define vbd_sz(_v) ((_v)->bdev->bd_part ? \
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(_v)->bdev->bd_part->nr_sects : get_capacity((_v)->bdev->bd_disk))
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unsigned long long vbd_size(struct vbd *vbd)
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{
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return vbd_sz(vbd);
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}
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unsigned int vbd_info(struct vbd *vbd)
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{
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return vbd->type | (vbd->readonly?VDISK_READONLY:0);
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}
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unsigned long vbd_secsize(struct vbd *vbd)
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{
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return bdev_logical_block_size(vbd->bdev);
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}
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int vbd_create(blkif_t *blkif, blkif_vdev_t handle, unsigned major,
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unsigned minor, int readonly, int cdrom)
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{
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struct vbd *vbd;
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struct block_device *bdev;
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vbd = &blkif->vbd;
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vbd->handle = handle;
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vbd->readonly = readonly;
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vbd->type = 0;
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vbd->pdevice = MKDEV(major, minor);
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bdev = open_by_devnum(vbd->pdevice,
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vbd->readonly ? FMODE_READ : FMODE_WRITE);
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if (IS_ERR(bdev)) {
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DPRINTK("vbd_creat: device %08x could not be opened.\n",
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vbd->pdevice);
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return -ENOENT;
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}
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vbd->bdev = bdev;
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if (vbd->bdev->bd_disk == NULL) {
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DPRINTK("vbd_creat: device %08x doesn't exist.\n",
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vbd->pdevice);
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vbd_free(vbd);
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return -ENOENT;
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}
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if (vbd->bdev->bd_disk->flags & GENHD_FL_CD || cdrom)
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vbd->type |= VDISK_CDROM;
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if (vbd->bdev->bd_disk->flags & GENHD_FL_REMOVABLE)
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vbd->type |= VDISK_REMOVABLE;
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DPRINTK("Successful creation of handle=%04x (dom=%u)\n",
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handle, blkif->domid);
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return 0;
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}
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void vbd_free(struct vbd *vbd)
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{
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if (vbd->bdev)
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blkdev_put(vbd->bdev, vbd->readonly ? FMODE_READ : FMODE_WRITE);
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vbd->bdev = NULL;
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}
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int vbd_translate(struct phys_req *req, blkif_t *blkif, int operation)
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{
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struct vbd *vbd = &blkif->vbd;
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int rc = -EACCES;
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if ((operation != READ) && vbd->readonly)
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goto out;
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if (unlikely((req->sector_number + req->nr_sects) > vbd_sz(vbd)))
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goto out;
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req->dev = vbd->pdevice;
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req->bdev = vbd->bdev;
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rc = 0;
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out:
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return rc;
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}
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