/* * Copyright (c) 2000-2006 Apple Computer, Inc. All rights reserved. * * @APPLE_OSREFERENCE_LICENSE_HEADER_START@ * * This file contains Original Code and/or Modifications of Original Code * as defined in and that are subject to the Apple Public Source License * Version 2.0 (the 'License'). You may not use this file except in * compliance with the License. The rights granted to you under the License * may not be used to create, or enable the creation or redistribution of, * unlawful or unlicensed copies of an Apple operating system, or to * circumvent, violate, or enable the circumvention or violation of, any * terms of an Apple operating system software license agreement. * * Please obtain a copy of the License at * http://www.opensource.apple.com/apsl/ and read it before using this file. * * The Original Code and all software distributed under the License are * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. * Please see the License for the specific language governing rights and * limitations under the License. * * @APPLE_OSREFERENCE_LICENSE_HEADER_END@ */ /* Copyright (c) 1995 NeXT Computer, Inc. All Rights Reserved */ /* * Copyright (c) 1989, 1993, 1995 * The Regents of the University of California. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by the University of * California, Berkeley and its contributors. * 4. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * @(#)spec_vnops.c 8.14 (Berkeley) 5/21/95 */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /* XXX following three prototypes should be in a header file somewhere */ extern int isdisk(dev_t dev, int type); extern dev_t chrtoblk(dev_t dev); extern int iskmemdev(dev_t dev); struct vnode *speclisth[SPECHSZ]; /* symbolic sleep message strings for devices */ char devopn[] = "devopn"; char devio[] = "devio"; char devwait[] = "devwait"; char devin[] = "devin"; char devout[] = "devout"; char devioc[] = "devioc"; char devcls[] = "devcls"; #define VOPFUNC int (*)(void *) int (**spec_vnodeop_p)(void *); struct vnodeopv_entry_desc spec_vnodeop_entries[] = { { &vnop_default_desc, (VOPFUNC)vn_default_error }, { &vnop_lookup_desc, (VOPFUNC)spec_lookup }, /* lookup */ { &vnop_create_desc, (VOPFUNC)err_create }, /* create */ { &vnop_mknod_desc, (VOPFUNC)err_mknod }, /* mknod */ { &vnop_open_desc, (VOPFUNC)spec_open }, /* open */ { &vnop_close_desc, (VOPFUNC)spec_close }, /* close */ { &vnop_access_desc, (VOPFUNC)spec_access }, /* access */ { &vnop_getattr_desc, (VOPFUNC)spec_getattr }, /* getattr */ { &vnop_setattr_desc, (VOPFUNC)spec_setattr }, /* setattr */ { &vnop_read_desc, (VOPFUNC)spec_read }, /* read */ { &vnop_write_desc, (VOPFUNC)spec_write }, /* write */ { &vnop_ioctl_desc, (VOPFUNC)spec_ioctl }, /* ioctl */ { &vnop_select_desc, (VOPFUNC)spec_select }, /* select */ { &vnop_revoke_desc, (VOPFUNC)nop_revoke }, /* revoke */ { &vnop_mmap_desc, (VOPFUNC)err_mmap }, /* mmap */ { &vnop_fsync_desc, (VOPFUNC)spec_fsync }, /* fsync */ { &vnop_remove_desc, (VOPFUNC)err_remove }, /* remove */ { &vnop_link_desc, (VOPFUNC)err_link }, /* link */ { &vnop_rename_desc, (VOPFUNC)err_rename }, /* rename */ { &vnop_mkdir_desc, (VOPFUNC)err_mkdir }, /* mkdir */ { &vnop_rmdir_desc, (VOPFUNC)err_rmdir }, /* rmdir */ { &vnop_symlink_desc, (VOPFUNC)err_symlink }, /* symlink */ { &vnop_readdir_desc, (VOPFUNC)err_readdir }, /* readdir */ { &vnop_readlink_desc, (VOPFUNC)err_readlink }, /* readlink */ { &vnop_inactive_desc, (VOPFUNC)nop_inactive }, /* inactive */ { &vnop_reclaim_desc, (VOPFUNC)nop_reclaim }, /* reclaim */ { &vnop_strategy_desc, (VOPFUNC)spec_strategy }, /* strategy */ { &vnop_pathconf_desc, (VOPFUNC)spec_pathconf }, /* pathconf */ { &vnop_advlock_desc, (VOPFUNC)err_advlock }, /* advlock */ { &vnop_bwrite_desc, (VOPFUNC)spec_bwrite }, /* bwrite */ { &vnop_pagein_desc, (VOPFUNC)err_pagein }, /* Pagein */ { &vnop_pageout_desc, (VOPFUNC)err_pageout }, /* Pageout */ { &vnop_copyfile_desc, (VOPFUNC)err_copyfile }, /* Copyfile */ { &vnop_blktooff_desc, (VOPFUNC)spec_blktooff }, /* blktooff */ { &vnop_offtoblk_desc, (VOPFUNC)spec_offtoblk }, /* offtoblk */ { &vnop_blockmap_desc, (VOPFUNC)spec_blockmap }, /* blockmap */ { (struct vnodeop_desc*)NULL, (int(*)())NULL } }; struct vnodeopv_desc spec_vnodeop_opv_desc = { &spec_vnodeop_p, spec_vnodeop_entries }; static void set_blocksize(vnode_t, dev_t); /* * Trivial lookup routine that always fails. */ int spec_lookup(struct vnop_lookup_args *ap) { *ap->a_vpp = NULL; return (ENOTDIR); } static void set_blocksize(struct vnode *vp, dev_t dev) { int (*size)(dev_t); int rsize; if ((major(dev) < nblkdev) && (size = bdevsw[major(dev)].d_psize)) { rsize = (*size)(dev); if (rsize <= 0) /* did size fail? */ vp->v_specsize = DEV_BSIZE; else vp->v_specsize = rsize; } else vp->v_specsize = DEV_BSIZE; } void set_fsblocksize(struct vnode *vp) { if (vp->v_type == VBLK) { dev_t dev = (dev_t)vp->v_rdev; int maj = major(dev); if ((u_int)maj >= (u_int)nblkdev) return; vnode_lock(vp); set_blocksize(vp, dev); vnode_unlock(vp); } } /* * Open a special file. */ int spec_open(struct vnop_open_args *ap) { struct proc *p = vfs_context_proc(ap->a_context); kauth_cred_t cred = vfs_context_ucred(ap->a_context); struct vnode *vp = ap->a_vp; dev_t bdev, dev = (dev_t)vp->v_rdev; int maj = major(dev); int error; /* * Don't allow open if fs is mounted -nodev. */ if (vp->v_mount && (vp->v_mount->mnt_flag & MNT_NODEV)) return (ENXIO); switch (vp->v_type) { case VCHR: if ((u_int)maj >= (u_int)nchrdev) return (ENXIO); if (cred != FSCRED && (ap->a_mode & FWRITE)) { /* * When running in very secure mode, do not allow * opens for writing of any disk character devices. */ if (securelevel >= 2 && isdisk(dev, VCHR)) return (EPERM); /* * When running in secure mode, do not allow opens * for writing of /dev/mem, /dev/kmem, or character * devices whose corresponding block devices are * currently mounted. */ if (securelevel >= 1) { if ((bdev = chrtoblk(dev)) != NODEV && check_mountedon(bdev, VBLK, &error)) return (error); if (iskmemdev(dev)) return (EPERM); } } if (cdevsw[maj].d_type == D_TTY) { vnode_lock(vp); vp->v_flag |= VISTTY; vnode_unlock(vp); } error = (*cdevsw[maj].d_open)(dev, ap->a_mode, S_IFCHR, p); return (error); case VBLK: if ((u_int)maj >= (u_int)nblkdev) return (ENXIO); /* * When running in very secure mode, do not allow * opens for writing of any disk block devices. */ if (securelevel >= 2 && cred != FSCRED && (ap->a_mode & FWRITE) && bdevsw[maj].d_type == D_DISK) return (EPERM); /* * Do not allow opens of block devices that are * currently mounted. */ if ( (error = vfs_mountedon(vp)) ) return (error); error = (*bdevsw[maj].d_open)(dev, ap->a_mode, S_IFBLK, p); if (!error) { u_int64_t blkcnt; u_int32_t blksize; int setsize = 0; u_int32_t size512 = 512; if (!VNOP_IOCTL(vp, DKIOCGETBLOCKSIZE, (caddr_t)&blksize, 0, ap->a_context)) { /* Switch to 512 byte sectors (temporarily) */ if (!VNOP_IOCTL(vp, DKIOCSETBLOCKSIZE, (caddr_t)&size512, FWRITE, ap->a_context)) { /* Get the number of 512 byte physical blocks. */ if (!VNOP_IOCTL(vp, DKIOCGETBLOCKCOUNT, (caddr_t)&blkcnt, 0, ap->a_context)) { setsize = 1; } } /* If it doesn't set back, we can't recover */ if (VNOP_IOCTL(vp, DKIOCSETBLOCKSIZE, (caddr_t)&blksize, FWRITE, ap->a_context)) error = ENXIO; } vnode_lock(vp); set_blocksize(vp, dev); /* * Cache the size in bytes of the block device for later * use by spec_write(). */ if (setsize) vp->v_specdevsize = blkcnt * (u_int64_t)size512; else vp->v_specdevsize = (u_int64_t)0; /* Default: Can't get */ vnode_unlock(vp); } return(error); default: panic("spec_open type"); } return (0); } /* * Vnode op for read */ int spec_read(struct vnop_read_args *ap) { struct vnode *vp = ap->a_vp; struct uio *uio = ap->a_uio; struct buf *bp; daddr64_t bn, nextbn; long bsize, bscale; int devBlockSize=0; int n, on; int error = 0; dev_t dev; #if DIAGNOSTIC if (uio->uio_rw != UIO_READ) panic("spec_read mode"); if (UIO_SEG_IS_USER_SPACE(uio->uio_segflg)) panic("spec_read proc"); #endif if (uio_resid(uio) == 0) return (0); switch (vp->v_type) { case VCHR: error = (*cdevsw[major(vp->v_rdev)].d_read) (vp->v_rdev, uio, ap->a_ioflag); return (error); case VBLK: if (uio->uio_offset < 0) return (EINVAL); dev = vp->v_rdev; devBlockSize = vp->v_specsize; if (devBlockSize > PAGE_SIZE) return (EINVAL); bscale = PAGE_SIZE / devBlockSize; bsize = bscale * devBlockSize; do { on = uio->uio_offset % bsize; bn = (daddr64_t)((uio->uio_offset / devBlockSize) &~ (bscale - 1)); if (vp->v_speclastr + bscale == bn) { nextbn = bn + bscale; error = buf_breadn(vp, bn, (int)bsize, &nextbn, (int *)&bsize, 1, NOCRED, &bp); } else error = buf_bread(vp, bn, (int)bsize, NOCRED, &bp); vnode_lock(vp); vp->v_speclastr = bn; vnode_unlock(vp); n = bsize - buf_resid(bp); if ((on > n) || error) { if (!error) error = EINVAL; buf_brelse(bp); return (error); } // LP64todo - fix this! n = min((unsigned)(n - on), uio_resid(uio)); error = uiomove((char *)0 + buf_dataptr(bp) + on, n, uio); if (n + on == bsize) buf_markaged(bp); buf_brelse(bp); } while (error == 0 && uio_resid(uio) > 0 && n != 0); return (error); default: panic("spec_read type"); } /* NOTREACHED */ return (0); } /* * Vnode op for write */ int spec_write(struct vnop_write_args *ap) { struct vnode *vp = ap->a_vp; struct uio *uio = ap->a_uio; struct buf *bp; daddr64_t bn; int bsize, blkmask, bscale; int io_sync; int io_size; int devBlockSize=0; int n, on; int error = 0; dev_t dev; #if DIAGNOSTIC if (uio->uio_rw != UIO_WRITE) panic("spec_write mode"); if (UIO_SEG_IS_USER_SPACE(uio->uio_segflg)) panic("spec_write proc"); #endif switch (vp->v_type) { case VCHR: error = (*cdevsw[major(vp->v_rdev)].d_write) (vp->v_rdev, uio, ap->a_ioflag); return (error); case VBLK: if (uio_resid(uio) == 0) return (0); if (uio->uio_offset < 0) return (EINVAL); io_sync = (ap->a_ioflag & IO_SYNC); // LP64todo - fix this! io_size = uio_resid(uio); dev = (vp->v_rdev); devBlockSize = vp->v_specsize; if (devBlockSize > PAGE_SIZE) return(EINVAL); bscale = PAGE_SIZE / devBlockSize; blkmask = bscale - 1; bsize = bscale * devBlockSize; do { bn = (daddr64_t)((uio->uio_offset / devBlockSize) &~ blkmask); on = uio->uio_offset % bsize; // LP64todo - fix this! n = min((unsigned)(bsize - on), uio_resid(uio)); /* * Use buf_getblk() as an optimization IFF: * * 1) We are reading exactly a block on a block * aligned boundary * 2) We know the size of the device from spec_open * 3) The read doesn't span the end of the device * * Otherwise, we fall back on buf_bread(). */ if (n == bsize && vp->v_specdevsize != (u_int64_t)0 && (uio->uio_offset + (u_int64_t)n) > vp->v_specdevsize) { /* reduce the size of the read to what is there */ n = (uio->uio_offset + (u_int64_t)n) - vp->v_specdevsize; } if (n == bsize) bp = buf_getblk(vp, bn, bsize, 0, 0, BLK_WRITE); else error = (int)buf_bread(vp, bn, bsize, NOCRED, &bp); /* Translate downstream error for upstream, if needed */ if (!error) error = (int)buf_error(bp); if (error) { buf_brelse(bp); return (error); } n = min(n, bsize - buf_resid(bp)); error = uiomove((char *)0 + buf_dataptr(bp) + on, n, uio); if (error) { buf_brelse(bp); return (error); } buf_markaged(bp); if (io_sync) error = buf_bwrite(bp); else { if ((n + on) == bsize) error = buf_bawrite(bp); else error = buf_bdwrite(bp); } } while (error == 0 && uio_resid(uio) > 0 && n != 0); return (error); default: panic("spec_write type"); } /* NOTREACHED */ return (0); } /* * Device ioctl operation. */ int spec_ioctl(struct vnop_ioctl_args *ap) { proc_t p = vfs_context_proc(ap->a_context); dev_t dev = ap->a_vp->v_rdev; switch (ap->a_vp->v_type) { case VCHR: return ((*cdevsw[major(dev)].d_ioctl)(dev, ap->a_command, ap->a_data, ap->a_fflag, p)); case VBLK: if (ap->a_command == 0 && (unsigned int)ap->a_data == B_TAPE) { if (bdevsw[major(dev)].d_type == D_TAPE) return (0); else return (1); } return ((*bdevsw[major(dev)].d_ioctl)(dev, ap->a_command, ap->a_data, ap->a_fflag, p)); default: panic("spec_ioctl"); /* NOTREACHED */ } return (0); } int spec_select(struct vnop_select_args *ap) { proc_t p = vfs_context_proc(ap->a_context); dev_t dev; switch (ap->a_vp->v_type) { default: return (1); /* XXX */ case VCHR: dev = ap->a_vp->v_rdev; return (*cdevsw[major(dev)].d_select)(dev, ap->a_which, ap->a_wql, p); } } /* * Synch buffers associated with a block device */ int spec_fsync_internal(vnode_t vp, int waitfor, __unused vfs_context_t context) { if (vp->v_type == VCHR) return (0); /* * Flush all dirty buffers associated with a block device. */ buf_flushdirtyblks(vp, waitfor == MNT_WAIT, 0, "spec_fsync"); return (0); } int spec_fsync(struct vnop_fsync_args *ap) { return spec_fsync_internal(ap->a_vp, ap->a_waitfor, ap->a_context); } /* * Just call the device strategy routine */ extern int hard_throttle_on_root; void IOSleep(int); // the low priority process may wait for at most LOWPRI_MAX_DELAY millisecond #define LOWPRI_INITIAL_WINDOW_MSECS 100 #define LOWPRI_WINDOW_MSECS_INC 50 #define LOWPRI_MAX_WINDOW_MSECS 200 #define LOWPRI_MAX_WAITING_MSECS 200 #define LOWPRI_SLEEP_INTERVAL 5 struct _throttle_io_info_t { struct timeval last_normal_IO_timestamp; struct timeval last_IO_timestamp; SInt32 numthreads_throttling; }; struct _throttle_io_info_t _throttle_io_info[LOWPRI_MAX_NUM_DEV]; int lowpri_IO_initial_window_msecs = LOWPRI_INITIAL_WINDOW_MSECS; int lowpri_IO_window_msecs_inc = LOWPRI_WINDOW_MSECS_INC; int lowpri_max_window_msecs = LOWPRI_MAX_WINDOW_MSECS; int lowpri_max_waiting_msecs = LOWPRI_MAX_WAITING_MSECS; SYSCTL_INT(_debug, OID_AUTO, lowpri_IO_initial_window_msecs, CTLFLAG_RW, &lowpri_IO_initial_window_msecs, LOWPRI_INITIAL_WINDOW_MSECS, ""); SYSCTL_INT(_debug, OID_AUTO, lowpri_IO_window_inc, CTLFLAG_RW, &lowpri_IO_window_msecs_inc, LOWPRI_INITIAL_WINDOW_MSECS, ""); SYSCTL_INT(_debug, OID_AUTO, lowpri_max_window_msecs, CTLFLAG_RW, &lowpri_max_window_msecs, LOWPRI_INITIAL_WINDOW_MSECS, ""); SYSCTL_INT(_debug, OID_AUTO, lowpri_max_waiting_msecs, CTLFLAG_RW, &lowpri_max_waiting_msecs, LOWPRI_INITIAL_WINDOW_MSECS, ""); void throttle_info_get_last_io_time(mount_t mp, struct timeval *tv) { size_t devbsdunit; devbsdunit = mp->mnt_devbsdunit; if (devbsdunit < LOWPRI_MAX_NUM_DEV) { *tv = _throttle_io_info[devbsdunit].last_IO_timestamp; } else { memset(tv, 0, sizeof(*tv)); } } void update_last_io_time(mount_t mp) { size_t devbsdunit; devbsdunit = mp->mnt_devbsdunit; if (devbsdunit < LOWPRI_MAX_NUM_DEV) { microuptime(&_throttle_io_info[devbsdunit].last_IO_timestamp); } } int throttle_io_will_be_throttled(int lowpri_window_msecs, size_t devbsdunit) { struct timeval elapsed; int elapsed_msecs; microuptime(&elapsed); timevalsub(&elapsed, &_throttle_io_info[devbsdunit].last_normal_IO_timestamp); elapsed_msecs = elapsed.tv_sec * 1000 + elapsed.tv_usec / 1000; if (lowpri_window_msecs == -1) // use the max waiting time lowpri_window_msecs = lowpri_max_waiting_msecs; return elapsed_msecs < lowpri_window_msecs; } void throttle_lowpri_io(boolean_t ok_to_sleep) { int i; int max_try_num; struct uthread *ut; ut = get_bsdthread_info(current_thread()); if (ut->uu_lowpri_window == 0) return; max_try_num = lowpri_max_waiting_msecs / LOWPRI_SLEEP_INTERVAL * MAX(1, _throttle_io_info[ut->uu_devbsdunit].numthreads_throttling); KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 97)) | DBG_FUNC_START, ut->uu_lowpri_window, 0, 0, 0, 0); if (ok_to_sleep == TRUE) { for (i=0; iuu_lowpri_window, ut->uu_devbsdunit)) { IOSleep(LOWPRI_SLEEP_INTERVAL); } else { break; } } } KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 97)) | DBG_FUNC_END, ut->uu_lowpri_window, i*5, 0, 0, 0); SInt32 oldValue; oldValue = OSDecrementAtomic(&_throttle_io_info[ut->uu_devbsdunit].numthreads_throttling); ut->uu_lowpri_window = 0; if (oldValue <= 0) { panic("%s: numthreads negative", __func__); } } int throttle_get_io_policy(struct uthread **ut) { int policy = IOPOL_DEFAULT; proc_t p = current_proc(); *ut = get_bsdthread_info(current_thread()); if (p != NULL) policy = p->p_iopol_disk; if (*ut != NULL) { // the I/O policy of the thread overrides that of the process // unless the I/O policy of the thread is default if ((*ut)->uu_iopol_disk != IOPOL_DEFAULT) policy = (*ut)->uu_iopol_disk; } return policy; } int spec_strategy(struct vnop_strategy_args *ap) { buf_t bp; int bflags; dev_t bdev; bp = ap->a_bp; bdev = buf_device(bp); bflags = buf_flags(bp); if (kdebug_enable) { int code = 0; if (bflags & B_READ) code |= DKIO_READ; if (bflags & B_ASYNC) code |= DKIO_ASYNC; if (bflags & B_META) code |= DKIO_META; else if (bflags & B_PAGEIO) code |= DKIO_PAGING; KERNEL_DEBUG_CONSTANT(FSDBG_CODE(DBG_DKRW, code) | DBG_FUNC_NONE, (unsigned int)bp, bdev, (int)buf_blkno(bp), buf_count(bp), 0); } if (((bflags & (B_PAGEIO | B_READ)) == (B_PAGEIO | B_READ)) && (buf_vnode(bp)->v_mount->mnt_kern_flag & MNTK_ROOTDEV)) hard_throttle_on_root = 1; if (lowpri_IO_initial_window_msecs) { struct uthread *ut; int policy; int is_throttleable_io = 0; int is_passive_io = 0; size_t devbsdunit; SInt32 oldValue; policy = throttle_get_io_policy(&ut); switch (policy) { case IOPOL_DEFAULT: case IOPOL_NORMAL: break; case IOPOL_THROTTLE: is_throttleable_io = 1; break; case IOPOL_PASSIVE: is_passive_io = 1; break; default: printf("unknown I/O policy %d", policy); break; } if (!is_throttleable_io && ISSET(bflags, B_PASSIVE)) is_passive_io |= 1; if (buf_vnode(bp)->v_mount != NULL) devbsdunit = buf_vnode(bp)->v_mount->mnt_devbsdunit; else devbsdunit = LOWPRI_MAX_NUM_DEV - 1; if (!is_throttleable_io) { if (!is_passive_io){ microuptime(&_throttle_io_info[devbsdunit].last_normal_IO_timestamp); } } else { /* * I'd really like to do the IOSleep here, but * we may be holding all kinds of filesystem related locks * and the pages for this I/O marked 'busy'... * we don't want to cause a normal task to block on * one of these locks while we're throttling a task marked * for low priority I/O... we'll mark the uthread and * do the delay just before we return from the system * call that triggered this I/O or from vnode_pagein */ if (ut->uu_lowpri_window == 0) { ut->uu_devbsdunit = devbsdunit; oldValue = OSIncrementAtomic(&_throttle_io_info[devbsdunit].numthreads_throttling); if (oldValue < 0) { panic("%s: numthreads negative", __func__); } ut->uu_lowpri_window = lowpri_IO_initial_window_msecs; ut->uu_lowpri_window += lowpri_IO_window_msecs_inc * oldValue; } else { if (ut->uu_devbsdunit != devbsdunit) { // the thread sends I/Os to different devices within the same system call // keep track of the numthreads in the right device OSDecrementAtomic(&_throttle_io_info[ut->uu_devbsdunit].numthreads_throttling); OSIncrementAtomic(&_throttle_io_info[devbsdunit].numthreads_throttling); ut->uu_devbsdunit = devbsdunit; } int numthreads = MAX(1, _throttle_io_info[devbsdunit].numthreads_throttling); ut->uu_lowpri_window += lowpri_IO_window_msecs_inc * numthreads; if (ut->uu_lowpri_window > lowpri_max_window_msecs * numthreads) ut->uu_lowpri_window = lowpri_max_window_msecs * numthreads; } } } if ((bflags & B_READ) == 0) { size_t devbsdunit; if (buf_vnode(bp)->v_mount != NULL) devbsdunit = buf_vnode(bp)->v_mount->mnt_devbsdunit; else devbsdunit = LOWPRI_MAX_NUM_DEV - 1; microuptime(&_throttle_io_info[devbsdunit].last_IO_timestamp); } (*bdevsw[major(bdev)].d_strategy)(bp); return (0); } /* * This is a noop, simply returning what one has been given. */ int spec_blockmap(__unused struct vnop_blockmap_args *ap) { return (ENOTSUP); } /* * Device close routine */ int spec_close(struct vnop_close_args *ap) { struct vnode *vp = ap->a_vp; dev_t dev = vp->v_rdev; int (*devclose)(dev_t, int, int, struct proc *); int mode, error; int flags = ap->a_fflag; struct proc *p = vfs_context_proc(ap->a_context); struct session *sessp; switch (vp->v_type) { case VCHR: /* * Hack: a tty device that is a controlling terminal * has a reference from the session structure. * We cannot easily tell that a character device is * a controlling terminal, unless it is the closing * process' controlling terminal. In that case, * if the reference count is 2 (this last descriptor * plus the session), release the reference from the session. */ sessp = proc_session(p); if (sessp != SESSION_NULL) { if ((vcount(vp) == 2) && (vp == sessp->s_ttyvp)) { session_lock(sessp); sessp->s_ttyvp = NULL; sessp->s_ttyvid = 0; sessp->s_ttyp = NULL; sessp->s_ttypgrpid = NO_PID; session_unlock(sessp); vnode_rele(vp); } session_rele(sessp); } devclose = cdevsw[major(dev)].d_close; mode = S_IFCHR; /* * close on last reference or on vnode revoke call */ if ((flags & IO_REVOKE) != 0) break; if (vcount(vp) > 1) return (0); break; case VBLK: #ifdef DEVFS_IMPLEMENTS_LOCKING /* * On last close of a block device (that isn't mounted) * we must invalidate any in core blocks, so that * we can, for instance, change floppy disks. */ if ((error = spec_fsync_internal(vp, MNT_WAIT, ap->a_context))) return (error); error = buf_invalidateblks(vp, BUF_WRITE_DATA, 0, 0); if (error) return (error); /* * Since every use (buffer, vnode, swap, blockmap) * holds a reference to the vnode, and because we mark * any other vnodes that alias this device, when the * sum of the reference counts on all the aliased * vnodes descends to one, we are on last close. */ if (vcount(vp) > 0) return (0); #else /* DEVFS_IMPLEMENTS_LOCKING */ /* * Since every use (buffer, vnode, swap, blockmap) * holds a reference to the vnode, and because we mark * any other vnodes that alias this device, when the * sum of the reference counts on all the aliased * vnodes descends to one, we are on last close. */ if (vcount(vp) > 0) return (0); /* * On last close of a block device (that isn't mounted) * we must invalidate any in core blocks, so that * we can, for instance, change floppy disks. */ if ((error = spec_fsync_internal(vp, MNT_WAIT, ap->a_context))) return (error); error = buf_invalidateblks(vp, BUF_WRITE_DATA, 0, 0); if (error) return (error); #endif /* DEVFS_IMPLEMENTS_LOCKING */ devclose = bdevsw[major(dev)].d_close; mode = S_IFBLK; break; default: panic("spec_close: not special"); return(EBADF); } return ((*devclose)(dev, flags, mode, p)); } /* * Return POSIX pathconf information applicable to special devices. */ int spec_pathconf(struct vnop_pathconf_args *ap) { switch (ap->a_name) { case _PC_LINK_MAX: *ap->a_retval = LINK_MAX; return (0); case _PC_MAX_CANON: *ap->a_retval = MAX_CANON; return (0); case _PC_MAX_INPUT: *ap->a_retval = MAX_INPUT; return (0); case _PC_PIPE_BUF: *ap->a_retval = PIPE_BUF; return (0); case _PC_CHOWN_RESTRICTED: *ap->a_retval = 200112; /* _POSIX_CHOWN_RESTRICTED */ return (0); case _PC_VDISABLE: *ap->a_retval = _POSIX_VDISABLE; return (0); default: return (EINVAL); } /* NOTREACHED */ } /* * Special device failed operation */ int spec_ebadf(__unused void *dummy) { return (EBADF); } /* Blktooff derives file offset from logical block number */ int spec_blktooff(struct vnop_blktooff_args *ap) { struct vnode *vp = ap->a_vp; switch (vp->v_type) { case VCHR: *ap->a_offset = (off_t)-1; /* failure */ return (ENOTSUP); case VBLK: printf("spec_blktooff: not implemented for VBLK\n"); *ap->a_offset = (off_t)-1; /* failure */ return (ENOTSUP); default: panic("spec_blktooff type"); } /* NOTREACHED */ return (0); } /* Offtoblk derives logical block number from file offset */ int spec_offtoblk(struct vnop_offtoblk_args *ap) { struct vnode *vp = ap->a_vp; switch (vp->v_type) { case VCHR: *ap->a_lblkno = (daddr64_t)-1; /* failure */ return (ENOTSUP); case VBLK: printf("spec_offtoblk: not implemented for VBLK\n"); *ap->a_lblkno = (daddr64_t)-1; /* failure */ return (ENOTSUP); default: panic("spec_offtoblk type"); } /* NOTREACHED */ return (0); }