475 lines
12 KiB
C
475 lines
12 KiB
C
/*-
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* Copyright (c) 2000-2003 Tor Egge
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/fcntl.h>
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#include <sys/file.h>
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#include <sys/stat.h>
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#include <sys/proc.h>
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#include <sys/limits.h>
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#include <sys/mount.h>
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#include <sys/namei.h>
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#include <sys/vnode.h>
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#include <sys/conf.h>
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#include <sys/filio.h>
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#include <sys/ttycom.h>
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#include <sys/bio.h>
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#include <sys/buf.h>
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#include <sys/rwlock.h>
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#include <ufs/ufs/extattr.h>
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#include <ufs/ufs/quota.h>
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#include <ufs/ufs/inode.h>
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#include <ufs/ufs/ufsmount.h>
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#include <ufs/ufs/ufs_extern.h>
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#include <ufs/ffs/fs.h>
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#include <ufs/ffs/ffs_extern.h>
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#include <vm/vm.h>
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#include <vm/vm_extern.h>
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#include <vm/vm_object.h>
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#include <sys/kernel.h>
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#include <sys/sysctl.h>
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static int ffs_rawread_readahead(struct vnode *vp,
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caddr_t udata,
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off_t offset,
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size_t len,
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struct thread *td,
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struct buf *bp);
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static int ffs_rawread_main(struct vnode *vp,
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struct uio *uio);
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static int ffs_rawread_sync(struct vnode *vp);
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int ffs_rawread(struct vnode *vp, struct uio *uio, int *workdone);
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SYSCTL_DECL(_vfs_ffs);
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static int ffsrawbufcnt = 4;
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SYSCTL_INT(_vfs_ffs, OID_AUTO, ffsrawbufcnt, CTLFLAG_RD, &ffsrawbufcnt, 0,
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"Buffers available for raw reads");
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static int allowrawread = 1;
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SYSCTL_INT(_vfs_ffs, OID_AUTO, allowrawread, CTLFLAG_RW, &allowrawread, 0,
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"Flag to enable raw reads");
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static int rawreadahead = 1;
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SYSCTL_INT(_vfs_ffs, OID_AUTO, rawreadahead, CTLFLAG_RW, &rawreadahead, 0,
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"Flag to enable readahead for long raw reads");
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static void
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ffs_rawread_setup(void *arg __unused)
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{
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ffsrawbufcnt = (nswbuf > 100 ) ? (nswbuf - (nswbuf >> 4)) : nswbuf - 8;
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}
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SYSINIT(ffs_raw, SI_SUB_VM_CONF, SI_ORDER_ANY, ffs_rawread_setup, NULL);
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static int
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ffs_rawread_sync(struct vnode *vp)
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{
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int error;
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int upgraded;
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struct bufobj *bo;
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struct mount *mp;
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vm_object_t obj;
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/* Check for dirty mmap, pending writes and dirty buffers */
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bo = &vp->v_bufobj;
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BO_LOCK(bo);
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VI_LOCK(vp);
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if (bo->bo_numoutput > 0 ||
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bo->bo_dirty.bv_cnt > 0 ||
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((obj = vp->v_object) != NULL &&
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(obj->flags & OBJ_MIGHTBEDIRTY) != 0)) {
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VI_UNLOCK(vp);
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BO_UNLOCK(bo);
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if (vn_start_write(vp, &mp, V_NOWAIT) != 0) {
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if (VOP_ISLOCKED(vp) != LK_EXCLUSIVE)
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upgraded = 1;
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else
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upgraded = 0;
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VOP_UNLOCK(vp, 0);
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(void) vn_start_write(vp, &mp, V_WAIT);
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VOP_LOCK(vp, LK_EXCLUSIVE);
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} else if (VOP_ISLOCKED(vp) != LK_EXCLUSIVE) {
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upgraded = 1;
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/* Upgrade to exclusive lock, this might block */
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VOP_LOCK(vp, LK_UPGRADE);
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} else
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upgraded = 0;
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VI_LOCK(vp);
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/* Check if vnode was reclaimed while unlocked. */
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if ((vp->v_iflag & VI_DOOMED) != 0) {
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VI_UNLOCK(vp);
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if (upgraded != 0)
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VOP_LOCK(vp, LK_DOWNGRADE);
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vn_finished_write(mp);
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return (EIO);
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}
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/* Attempt to msync mmap() regions to clean dirty mmap */
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if ((obj = vp->v_object) != NULL &&
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(obj->flags & OBJ_MIGHTBEDIRTY) != 0) {
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VI_UNLOCK(vp);
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VM_OBJECT_WLOCK(obj);
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vm_object_page_clean(obj, 0, 0, OBJPC_SYNC);
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VM_OBJECT_WUNLOCK(obj);
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} else
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VI_UNLOCK(vp);
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/* Wait for pending writes to complete */
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BO_LOCK(bo);
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error = bufobj_wwait(&vp->v_bufobj, 0, 0);
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if (error != 0) {
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/* XXX: can't happen with a zero timeout ??? */
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BO_UNLOCK(bo);
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if (upgraded != 0)
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VOP_LOCK(vp, LK_DOWNGRADE);
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vn_finished_write(mp);
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return (error);
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}
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/* Flush dirty buffers */
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if (bo->bo_dirty.bv_cnt > 0) {
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BO_UNLOCK(bo);
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if ((error = ffs_syncvnode(vp, MNT_WAIT, 0)) != 0) {
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if (upgraded != 0)
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VOP_LOCK(vp, LK_DOWNGRADE);
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vn_finished_write(mp);
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return (error);
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}
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BO_LOCK(bo);
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if (bo->bo_numoutput > 0 || bo->bo_dirty.bv_cnt > 0)
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panic("ffs_rawread_sync: dirty bufs");
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}
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BO_UNLOCK(bo);
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if (upgraded != 0)
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VOP_LOCK(vp, LK_DOWNGRADE);
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vn_finished_write(mp);
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} else {
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VI_UNLOCK(vp);
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BO_UNLOCK(bo);
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}
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return 0;
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}
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static int
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ffs_rawread_readahead(struct vnode *vp,
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caddr_t udata,
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off_t offset,
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size_t len,
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struct thread *td,
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struct buf *bp)
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{
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int error;
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u_int iolen;
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off_t blockno;
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int blockoff;
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int bsize;
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struct vnode *dp;
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int bforwards;
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struct inode *ip;
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ufs2_daddr_t blkno;
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bsize = vp->v_mount->mnt_stat.f_iosize;
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ip = VTOI(vp);
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dp = ITODEVVP(ip);
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iolen = ((vm_offset_t) udata) & PAGE_MASK;
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bp->b_bcount = len;
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if (bp->b_bcount + iolen > bp->b_kvasize) {
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bp->b_bcount = bp->b_kvasize;
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if (iolen != 0)
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bp->b_bcount -= PAGE_SIZE;
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}
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bp->b_flags = 0; /* XXX necessary ? */
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bp->b_iocmd = BIO_READ;
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bp->b_iodone = bdone;
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bp->b_data = udata;
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blockno = offset / bsize;
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blockoff = (offset % bsize) / DEV_BSIZE;
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if ((daddr_t) blockno != blockno) {
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return EINVAL; /* blockno overflow */
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}
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bp->b_lblkno = bp->b_blkno = blockno;
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error = ufs_bmaparray(vp, bp->b_lblkno, &blkno, NULL, &bforwards, NULL);
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if (error != 0)
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return error;
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if (blkno == -1) {
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/* Fill holes with NULs to preserve semantics */
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if (bp->b_bcount + blockoff * DEV_BSIZE > bsize)
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bp->b_bcount = bsize - blockoff * DEV_BSIZE;
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bp->b_bufsize = bp->b_bcount;
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if (vmapbuf(bp, 1) < 0)
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return EFAULT;
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maybe_yield();
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bzero(bp->b_data, bp->b_bufsize);
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/* Mark operation completed (similar to bufdone()) */
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bp->b_resid = 0;
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bp->b_flags |= B_DONE;
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return 0;
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}
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bp->b_blkno = blkno + blockoff;
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bp->b_offset = bp->b_iooffset = (blkno + blockoff) * DEV_BSIZE;
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if (bp->b_bcount + blockoff * DEV_BSIZE > bsize * (1 + bforwards))
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bp->b_bcount = bsize * (1 + bforwards) - blockoff * DEV_BSIZE;
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bp->b_bufsize = bp->b_bcount;
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if (vmapbuf(bp, 1) < 0)
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return EFAULT;
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BO_STRATEGY(&dp->v_bufobj, bp);
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return 0;
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}
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static int
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ffs_rawread_main(struct vnode *vp,
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struct uio *uio)
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{
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int error, nerror;
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struct buf *bp, *nbp, *tbp;
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u_int iolen;
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caddr_t udata;
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long resid;
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off_t offset;
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struct thread *td;
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td = uio->uio_td ? uio->uio_td : curthread;
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udata = uio->uio_iov->iov_base;
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resid = uio->uio_resid;
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offset = uio->uio_offset;
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/*
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* keep the process from being swapped
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*/
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PHOLD(td->td_proc);
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error = 0;
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nerror = 0;
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bp = NULL;
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nbp = NULL;
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while (resid > 0) {
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if (bp == NULL) { /* Setup first read */
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/* XXX: Leave some bufs for swap */
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bp = getpbuf(&ffsrawbufcnt);
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pbgetvp(vp, bp);
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error = ffs_rawread_readahead(vp, udata, offset,
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resid, td, bp);
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if (error != 0)
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break;
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if (resid > bp->b_bufsize) { /* Setup fist readahead */
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/* XXX: Leave bufs for swap */
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if (rawreadahead != 0)
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nbp = trypbuf(&ffsrawbufcnt);
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else
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nbp = NULL;
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if (nbp != NULL) {
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pbgetvp(vp, nbp);
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nerror = ffs_rawread_readahead(vp,
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udata +
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bp->b_bufsize,
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offset +
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bp->b_bufsize,
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resid -
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bp->b_bufsize,
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td,
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nbp);
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if (nerror) {
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pbrelvp(nbp);
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relpbuf(nbp, &ffsrawbufcnt);
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nbp = NULL;
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}
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}
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}
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}
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bwait(bp, PRIBIO, "rawrd");
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vunmapbuf(bp);
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iolen = bp->b_bcount - bp->b_resid;
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if (iolen == 0 && (bp->b_ioflags & BIO_ERROR) == 0) {
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nerror = 0; /* Ignore possible beyond EOF error */
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break; /* EOF */
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}
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if ((bp->b_ioflags & BIO_ERROR) != 0) {
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error = bp->b_error;
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break;
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}
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resid -= iolen;
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udata += iolen;
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offset += iolen;
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if (iolen < bp->b_bufsize) {
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/* Incomplete read. Try to read remaining part */
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error = ffs_rawread_readahead(vp,
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udata,
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offset,
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bp->b_bufsize - iolen,
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td,
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bp);
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if (error != 0)
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break;
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} else if (nbp != NULL) { /* Complete read with readahead */
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tbp = bp;
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bp = nbp;
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nbp = tbp;
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if (resid <= bp->b_bufsize) { /* No more readaheads */
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pbrelvp(nbp);
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relpbuf(nbp, &ffsrawbufcnt);
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nbp = NULL;
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} else { /* Setup next readahead */
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nerror = ffs_rawread_readahead(vp,
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udata +
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bp->b_bufsize,
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offset +
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bp->b_bufsize,
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resid -
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bp->b_bufsize,
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td,
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nbp);
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if (nerror != 0) {
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pbrelvp(nbp);
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relpbuf(nbp, &ffsrawbufcnt);
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nbp = NULL;
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}
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}
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} else if (nerror != 0) {/* Deferred Readahead error */
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break;
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} else if (resid > 0) { /* More to read, no readahead */
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error = ffs_rawread_readahead(vp, udata, offset,
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resid, td, bp);
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if (error != 0)
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break;
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}
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}
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if (bp != NULL) {
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pbrelvp(bp);
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relpbuf(bp, &ffsrawbufcnt);
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}
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if (nbp != NULL) { /* Run down readahead buffer */
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bwait(nbp, PRIBIO, "rawrd");
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vunmapbuf(nbp);
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pbrelvp(nbp);
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relpbuf(nbp, &ffsrawbufcnt);
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}
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if (error == 0)
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error = nerror;
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PRELE(td->td_proc);
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uio->uio_iov->iov_base = udata;
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uio->uio_resid = resid;
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uio->uio_offset = offset;
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return error;
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}
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int
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ffs_rawread(struct vnode *vp,
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struct uio *uio,
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int *workdone)
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{
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if (allowrawread != 0 &&
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uio->uio_iovcnt == 1 &&
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uio->uio_segflg == UIO_USERSPACE &&
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uio->uio_resid == uio->uio_iov->iov_len &&
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(((uio->uio_td != NULL) ? uio->uio_td : curthread)->td_pflags &
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TDP_DEADLKTREAT) == 0) {
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int secsize; /* Media sector size */
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off_t filebytes; /* Bytes left of file */
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int blockbytes; /* Bytes left of file in full blocks */
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int partialbytes; /* Bytes in last partial block */
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int skipbytes; /* Bytes not to read in ffs_rawread */
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struct inode *ip;
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int error;
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/* Only handle sector aligned reads */
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ip = VTOI(vp);
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secsize = ITODEVVP(ip)->v_bufobj.bo_bsize;
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if ((uio->uio_offset & (secsize - 1)) == 0 &&
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(uio->uio_resid & (secsize - 1)) == 0) {
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/* Sync dirty pages and buffers if needed */
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error = ffs_rawread_sync(vp);
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if (error != 0)
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return error;
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/* Check for end of file */
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if (ip->i_size > uio->uio_offset) {
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filebytes = ip->i_size - uio->uio_offset;
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/* No special eof handling needed ? */
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if (uio->uio_resid <= filebytes) {
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*workdone = 1;
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return ffs_rawread_main(vp, uio);
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}
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partialbytes = ((unsigned int) ip->i_size) %
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ITOFS(ip)->fs_bsize;
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blockbytes = (int) filebytes - partialbytes;
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if (blockbytes > 0) {
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skipbytes = uio->uio_resid -
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blockbytes;
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uio->uio_resid = blockbytes;
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error = ffs_rawread_main(vp, uio);
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uio->uio_resid += skipbytes;
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if (error != 0)
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return error;
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/* Read remaining part using buffer */
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}
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}
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}
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}
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*workdone = 0;
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return 0;
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}
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