text: /*	$OpenBSD: ffs_vnops.c,v 1.62 2011/04/12 19:45:43 beck Exp $	*/
  /*	$NetBSD: ffs_vnops.c,v 1.7 1996/05/11 18:27:24 mycroft Exp $	*/
  
  /*
   * Copyright (c) 1982, 1986, 1989, 1993
   *	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. 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.
   *
   *	@(#)ffs_vnops.c	8.10 (Berkeley) 8/10/94
   */
  
  #include <sys/param.h>
  #include <sys/systm.h>
  #include <sys/resourcevar.h>
  #include <sys/kernel.h>
  #include <sys/file.h>
  #include <sys/stat.h>
  #include <sys/buf.h>
  #include <sys/proc.h>
  #include <sys/conf.h>
  #include <sys/mount.h>
  #include <sys/vnode.h>
  #include <sys/malloc.h>
  #include <sys/signalvar.h>
  #include <sys/pool.h>
  #include <sys/event.h>
  
  #include <uvm/uvm_extern.h>
  
  #include <miscfs/specfs/specdev.h>
  #include <miscfs/fifofs/fifo.h>
  
  #include <ufs/ufs/quota.h>
  #include <ufs/ufs/inode.h>
  #include <ufs/ufs/dir.h>
  #include <ufs/ufs/ufs_extern.h>
  #include <ufs/ufs/ufsmount.h>
  
  #include <ufs/ffs/fs.h>
  #include <ufs/ffs/ffs_extern.h>
  
  struct vops ffs_vops = {
  	.vop_lookup	= ufs_lookup,
  	.vop_create	= ufs_create,
  	.vop_mknod	= ufs_mknod,
  	.vop_open	= ufs_open,
  	.vop_close	= ufs_close,
  	.vop_access	= ufs_access,
  	.vop_getattr	= ufs_getattr,
  	.vop_setattr	= ufs_setattr,
  	.vop_read	= ffs_read,
  	.vop_write	= ffs_write,
  	.vop_ioctl	= ufs_ioctl,
  	.vop_poll	= ufs_poll,
  	.vop_kqfilter	= ufs_kqfilter,
  	.vop_revoke	= vop_generic_revoke,
  	.vop_fsync	= ffs_fsync,
  	.vop_remove	= ufs_remove,
  	.vop_link	= ufs_link,
  	.vop_rename	= ufs_rename,
  	.vop_mkdir	= ufs_mkdir,
  	.vop_rmdir	= ufs_rmdir,
  	.vop_symlink	= ufs_symlink,
  	.vop_readdir	= ufs_readdir,
  	.vop_readlink	= ufs_readlink,
  	.vop_abortop	= vop_generic_abortop,
  	.vop_inactive	= ufs_inactive,
  	.vop_reclaim	= ffs_reclaim,
  	.vop_lock	= ufs_lock,
  	.vop_unlock	= ufs_unlock,
  	.vop_bmap	= ufs_bmap,
  	.vop_strategy	= ufs_strategy,
  	.vop_print	= ufs_print,
  	.vop_islocked	= ufs_islocked,
  	.vop_pathconf	= ufs_pathconf,
  	.vop_advlock	= ufs_advlock,
  	.vop_reallocblks = ffs_reallocblks,
  	.vop_bwrite	= vop_generic_bwrite
  };
  
  struct vops ffs_specvops = {
  	.vop_close	= ufsspec_close,
  	.vop_access	= ufs_access,
  	.vop_getattr	= ufs_getattr,
  	.vop_setattr	= ufs_setattr,
  	.vop_read	= ufsspec_read,
  	.vop_write	= ufsspec_write,
  	.vop_fsync	= ffs_fsync,
  	.vop_inactive	= ufs_inactive,
  	.vop_reclaim	= ffs_reclaim,
  	.vop_lock	= ufs_lock,
  	.vop_unlock	= ufs_unlock,
  	.vop_print	= ufs_print,
  	.vop_islocked	= ufs_islocked,
  
  	/* XXX: Keep in sync with spec_vops */
  	.vop_lookup	= vop_generic_lookup,
  	.vop_create	= spec_badop,
  	.vop_mknod	= spec_badop,
  	.vop_open	= spec_open,
  	.vop_ioctl	= spec_ioctl,
  	.vop_poll	= spec_poll,
  	.vop_kqfilter	= spec_kqfilter,
  	.vop_revoke	= vop_generic_revoke,
  	.vop_remove	= spec_badop,
  	.vop_link	= spec_badop,
  	.vop_rename	= spec_badop,
  	.vop_mkdir	= spec_badop,
  	.vop_rmdir	= spec_badop,
  	.vop_symlink	= spec_badop,
  	.vop_readdir	= spec_badop,
  	.vop_readlink	= spec_badop,
  	.vop_abortop	= spec_badop,
  	.vop_bmap	= vop_generic_bmap,
  	.vop_strategy	= spec_strategy,
  	.vop_pathconf	= spec_pathconf,
  	.vop_advlock	= spec_advlock,
  	.vop_bwrite	= vop_generic_bwrite,
  };
  
  #ifdef FIFO
  struct vops ffs_fifovops = {
  	.vop_close	= ufsfifo_close,
  	.vop_access	= ufs_access,
  	.vop_getattr	= ufs_getattr,
  	.vop_setattr	= ufs_setattr,
  	.vop_read	= ufsfifo_read,
  	.vop_write	= ufsfifo_write,
  	.vop_fsync	= ffs_fsync,
  	.vop_inactive	= ufs_inactive,
  	.vop_reclaim	= ffsfifo_reclaim,
  	.vop_lock	= ufs_lock,
  	.vop_unlock	= ufs_unlock,
  	.vop_print	= ufs_print,
  	.vop_islocked	= ufs_islocked,
  	.vop_bwrite	= vop_generic_bwrite,
  
  	/* XXX: Keep in sync with fifo_vops */
  	.vop_lookup	= vop_generic_lookup,
  	.vop_create	= fifo_badop,
  	.vop_mknod	= fifo_badop,
  	.vop_open	= fifo_open,
  	.vop_ioctl	= fifo_ioctl,
  	.vop_poll	= fifo_poll,
  	.vop_kqfilter	= fifo_kqfilter,
  	.vop_revoke	= vop_generic_revoke,
  	.vop_remove	= fifo_badop,
  	.vop_link	= fifo_badop,
  	.vop_rename	= fifo_badop,
  	.vop_mkdir	= fifo_badop,
  	.vop_rmdir	= fifo_badop,
  	.vop_symlink	= fifo_badop,
  	.vop_readdir	= fifo_badop,
  	.vop_readlink	= fifo_badop,
  	.vop_abortop	= fifo_badop,
  	.vop_bmap	= vop_generic_bmap,
  	.vop_strategy	= fifo_badop,
  	.vop_pathconf	= fifo_pathconf,
  	.vop_advlock	= fifo_advlock
  };
  #endif /* FIFO */
  
  /*
   * Enabling cluster read/write operations.
   */
  int doclusterread = 1;
  int doclusterwrite = 1;
  
  /*
   * Vnode op for reading.
   */
  int
  ffs_read(void *v)
  {
  	struct vop_read_args *ap = v;
  	struct vnode *vp;
  	struct inode *ip;
  	struct uio *uio;
  	struct fs *fs;
  	struct buf *bp;
  	daddr64_t lbn, nextlbn;
  	off_t bytesinfile;
  	long size, xfersize, blkoffset;
  	mode_t mode;
  	int error;
  
  	vp = ap->a_vp;
  	ip = VTOI(vp);
  	mode = DIP(ip, mode);
  	uio = ap->a_uio;
  
  #ifdef DIAGNOSTIC
  	if (uio->uio_rw != UIO_READ)
  		panic("ffs_read: mode");
  
  	if (vp->v_type == VLNK) {
  		if ((int)DIP(ip, size) < vp->v_mount->mnt_maxsymlinklen ||
  		    (vp->v_mount->mnt_maxsymlinklen == 0 &&
  		     DIP(ip, blocks) == 0))
  			panic("ffs_read: short symlink");
  	} else if (vp->v_type != VREG && vp->v_type != VDIR)
  		panic("ffs_read: type %d", vp->v_type);
  #endif
  	fs = ip->i_fs;
  	if ((u_int64_t)uio->uio_offset > fs->fs_maxfilesize)
  		return (EFBIG);
  
  	if (uio->uio_resid == 0)
  		return (0);
  
  	for (error = 0, bp = NULL; uio->uio_resid > 0; bp = NULL) {
  		if ((bytesinfile = DIP(ip, size) - uio->uio_offset) <= 0)
  			break;
  		lbn = lblkno(fs, uio->uio_offset);
  		nextlbn = lbn + 1;
  		size = fs->fs_bsize;	/* WAS blksize(fs, ip, lbn); */
  		blkoffset = blkoff(fs, uio->uio_offset);
  		xfersize = fs->fs_bsize - blkoffset;
  		if (uio->uio_resid < xfersize)
  			xfersize = uio->uio_resid;
  		if (bytesinfile < xfersize)
  			xfersize = bytesinfile;
  
  		if (lblktosize(fs, nextlbn) >= DIP(ip, size))
  			error = bread(vp, lbn, size, NOCRED, &bp);
  		else if (lbn - 1 == ip->i_ci.ci_lastr) {
  			error = bread_cluster(vp, lbn, size, &bp);
  		} else
  			error = bread(vp, lbn, size, NOCRED, &bp);
  
  		if (error)
  			break;
  		ip->i_ci.ci_lastr = lbn;
  
  		/*
  		 * We should only get non-zero b_resid when an I/O error
  		 * has occurred, which should cause us to break above.
  		 * However, if the short read did not cause an error,
  		 * then we want to ensure that we do not uiomove bad
  		 * or uninitialized data.
  		 */
  		size -= bp->b_resid;
  		if (size < xfersize) {
  			if (size == 0)
  				break;
  			xfersize = size;
  		}
  		error = uiomove((char *)bp->b_data + blkoffset, (int)xfersize,
  				uio);
  		if (error)
  			break;
  		brelse(bp);
  	}
  	if (bp != NULL)
  		brelse(bp);
  	if (!(vp->v_mount->mnt_flag & MNT_NOATIME) ||
  	    (ip->i_flag & (IN_CHANGE | IN_UPDATE))) {
  		ip->i_flag |= IN_ACCESS;
  	}
  	return (error);
  }
  
  /*
   * Vnode op for writing.
   */
  int
  ffs_write(void *v)
  {
  	struct vop_write_args *ap = v;
  	struct vnode *vp;
  	struct uio *uio;
  	struct inode *ip;
  	struct fs *fs;
  	struct buf *bp;
  	struct proc *p;
  	daddr64_t lbn;
  	off_t osize;
  	int blkoffset, error, extended, flags, ioflag, resid, size, xfersize;
  	extern int num_indirdep, max_indirdep;
  
  	extended = 0;
  	ioflag = ap->a_ioflag;
  	uio = ap->a_uio;
  	vp = ap->a_vp;
  	ip = VTOI(vp);
  
  #ifdef DIAGNOSTIC
  	if (uio->uio_rw != UIO_WRITE)
  		panic("ffs_write: mode");
  #endif
  
  	/*
  	 * If writing 0 bytes, succeed and do not change
  	 * update time or file offset (standards compliance)
  	 */
  	if (uio->uio_resid == 0)
  		return (0);
  
  	switch (vp->v_type) {
  	case VREG:
  		if (ioflag & IO_APPEND)
  			uio->uio_offset = DIP(ip, size);
  		if ((DIP(ip, flags) & APPEND) && uio->uio_offset != DIP(ip, size))
  			return (EPERM);
  		/* FALLTHROUGH */
  	case VLNK:
  		break;
  	case VDIR:
  		if ((ioflag & IO_SYNC) == 0)
  			panic("ffs_write: nonsync dir write");
  		break;
  	default:
  		panic("ffs_write: type");
  	}
  
  	fs = ip->i_fs;
  	if (uio->uio_offset < 0 ||
  	    (u_int64_t)uio->uio_offset + uio->uio_resid > fs->fs_maxfilesize)
  		return (EFBIG);
  	/*
  	 * Maybe this should be above the vnode op call, but so long as
  	 * file servers have no limits, I don't think it matters.
  	 */
  	p = uio->uio_procp;
  	if (vp->v_type == VREG && p && !(ioflag & IO_NOLIMIT) &&
  	    uio->uio_offset + uio->uio_resid >
  	    p->p_rlimit[RLIMIT_FSIZE].rlim_cur) {
  		psignal(p, SIGXFSZ);
  		return (EFBIG);
  	}
  
  	resid = uio->uio_resid;
  	osize = DIP(ip, size);
  	flags = ioflag & IO_SYNC ? B_SYNC : 0;
  
  	for (error = 0; uio->uio_resid > 0;) {
  		lbn = lblkno(fs, uio->uio_offset);
  		blkoffset = blkoff(fs, uio->uio_offset);
  		xfersize = fs->fs_bsize - blkoffset;
  		if (uio->uio_resid < xfersize)
  			xfersize = uio->uio_resid;
  		if (fs->fs_bsize > xfersize)
  			flags |= B_CLRBUF;
  		else
  			flags &= ~B_CLRBUF;
  
  		if ((error = UFS_BUF_ALLOC(ip, uio->uio_offset, xfersize,
  			 ap->a_cred, flags, &bp)) != 0)
  			break;
  		if (uio->uio_offset + xfersize > DIP(ip, size)) {
  			DIP_ASSIGN(ip, size, uio->uio_offset + xfersize);
  			uvm_vnp_setsize(vp, DIP(ip, size));
  			/* Are we extending into an indirect block? */
  			if (bp->b_lblkno < NDADDR)
  				extended = 1;
  			else
  				extended = 2;
  		}
  		(void)uvm_vnp_uncache(vp);
  
  		size = blksize(fs, ip, lbn) - bp->b_resid;
  		if (size < xfersize)
  			xfersize = size;
  
  		error =
  		    uiomove((char *)bp->b_data + blkoffset, xfersize, uio);
  
  		if (error != 0)
  			bzero((char *)bp->b_data + blkoffset, xfersize);
  
  		if (ioflag & IO_SYNC)
  			(void)bwrite(bp);
  		else if (xfersize + blkoffset == fs->fs_bsize) {
  			if (doclusterwrite)
  				cluster_write(bp, &ip->i_ci, DIP(ip, size));
  			else
  				bawrite(bp);
  		} else
  			bdwrite(bp);
  
  		if (error || xfersize == 0)
  			break;
  		ip->i_flag |= IN_CHANGE | IN_UPDATE;
  	}
  	/*
  	 * If we successfully wrote any data, and we are not the superuser
  	 * we clear the setuid and setgid bits as a precaution against
  	 * tampering.
  	 */
  	if (resid > uio->uio_resid && ap->a_cred && ap->a_cred->cr_uid != 0)
  		DIP_ASSIGN(ip, mode, DIP(ip, mode) & ~(ISUID | ISGID));
  	if (resid > uio->uio_resid)
  		VN_KNOTE(vp, NOTE_WRITE | (extended ? NOTE_EXTEND : 0));
  	if (error) {
  		if (ioflag & IO_UNIT) {
  			(void)UFS_TRUNCATE(ip, osize,
  			    ioflag & IO_SYNC, ap->a_cred);
  			uio->uio_offset -= resid - uio->uio_resid;
  			uio->uio_resid = resid;
  		}
  	} else if (resid > uio->uio_resid) {
  		if (ioflag & IO_SYNC)
  			error = UFS_UPDATE(ip, MNT_WAIT);
  		if (DOINGSOFTDEP(vp) && num_indirdep > max_indirdep)
  			if (extended > 1) {
  				/*
  				 * If the number of pending indirect block
  				 * dependencies is sufficiently close to the
  				 * maximum number of simultaneously mappable
  				 * buffers force a sync on the vnode to prevent
  				 * buffer cache exhaustion.
  				 */
  				VOP_FSYNC(vp, p->p_ucred, MNT_WAIT, p);
  			}
  	}
  	return (error);
  }
  
  /*
   * Synch an open file.
   */
  int
  ffs_fsync(void *v)
  {
  	struct vop_fsync_args *ap = v;
  	struct vnode *vp = ap->a_vp;
  	struct buf *bp, *nbp;
  	int s, error, passes, skipmeta;
  
  	if (vp->v_type == VBLK &&
  	    vp->v_specmountpoint != NULL &&
  	    (vp->v_specmountpoint->mnt_flag & MNT_SOFTDEP))
  		softdep_fsync_mountdev(vp, ap->a_waitfor);
  
  	/*
  	 * Flush all dirty buffers associated with a vnode.
  	 */
  	passes = NIADDR + 1;
  	skipmeta = 0;
  	if (ap->a_waitfor == MNT_WAIT)
  		skipmeta = 1;
  	s = splbio();
  loop:
  	for (bp = LIST_FIRST(&vp->v_dirtyblkhd); bp;
  	     bp = LIST_NEXT(bp, b_vnbufs))
  		bp->b_flags &= ~B_SCANNED;
  	for (bp = LIST_FIRST(&vp->v_dirtyblkhd); bp; bp = nbp) {
  		nbp = LIST_NEXT(bp, b_vnbufs);
  		/* 
  		 * Reasons to skip this buffer: it has already been considered
  		 * on this pass, this pass is the first time through on a
  		 * synchronous flush request and the buffer being considered
  		 * is metadata, the buffer has dependencies that will cause
  		 * it to be redirtied and it has not already been deferred,
  		 * or it is already being written.
  		 */
  		if (bp->b_flags & (B_BUSY | B_SCANNED))
  			continue;
  		if ((bp->b_flags & B_DELWRI) == 0)
  			panic("ffs_fsync: not dirty");
  		if (skipmeta && bp->b_lblkno < 0)
  			continue;
  		if (ap->a_waitfor != MNT_WAIT &&
  		    LIST_FIRST(&bp->b_dep) != NULL &&
  		    (bp->b_flags & B_DEFERRED) == 0 &&
  		    buf_countdeps(bp, 0, 1)) {
  			bp->b_flags |= B_DEFERRED;
  			continue;
  		}
  
  		bremfree(bp);
  		buf_acquire(bp);
  		bp->b_flags |= B_SCANNED;
  		splx(s);
  		/*
  		 * On our final pass through, do all I/O synchronously
  		 * so that we can find out if our flush is failing
  		 * because of write errors.
  		 */
  		if (passes > 0 || ap->a_waitfor != MNT_WAIT)
  			(void) bawrite(bp);
  		else if ((error = bwrite(bp)) != 0)
  			return (error);
  		s = splbio();
  		/*
  		 * Since we may have slept during the I/O, we need
  		 * to start from a known point.
  		 */
  		nbp = LIST_FIRST(&vp->v_dirtyblkhd);
  	}
  	if (skipmeta) {
  		skipmeta = 0;
  		goto loop;
  	}
  	if (ap->a_waitfor == MNT_WAIT) {
  		vwaitforio(vp, 0, "ffs_fsync", 0);
  
  		/*
  		 * Ensure that any filesystem metadata associated
  		 * with the vnode has been written.
  		 */
  		splx(s);
  		if ((error = softdep_sync_metadata(ap)) != 0)
  			return (error);
  		s = splbio();
  		if (!LIST_EMPTY(&vp->v_dirtyblkhd)) {
  			/*
  			 * Block devices associated with filesystems may
  			 * have new I/O requests posted for them even if
  			 * the vnode is locked, so no amount of trying will
  			 * get them clean. Thus we give block devices a
  			 * good effort, then just give up. For all other file
  			 * types, go around and try again until it is clean.
  			 */
  			if (passes > 0) {
  				passes -= 1;
  				goto loop;
  			}
  #ifdef DIAGNOSTIC
  			if (vp->v_type != VBLK)
  				vprint("ffs_fsync: dirty", vp);
  #endif
  		}
  	}
  	splx(s);
  	return (UFS_UPDATE(VTOI(vp), ap->a_waitfor == MNT_WAIT));
  }
  
  /*
   * Reclaim an inode so that it can be used for other purposes.
   */
  int
  ffs_reclaim(void *v)
  {
  	struct vop_reclaim_args *ap = v;
  	struct vnode *vp = ap->a_vp;
  	struct inode *ip = VTOI(vp);
  	int error;
  
  	if ((error = ufs_reclaim(vp, ap->a_p)) != 0)
  		return (error);
  
  	if (ip->i_din1 != NULL) {
  #ifdef FFS2
  		if (ip->i_ump->um_fstype == UM_UFS2)
  			pool_put(&ffs_dinode2_pool, ip->i_din2);
  		else
  #endif
  			pool_put(&ffs_dinode1_pool, ip->i_din1);
  	}
  
  	pool_put(&ffs_ino_pool, ip);
  
  	vp->v_data = NULL;
  
  	return (0);
  }
  
  #ifdef FIFO
  int
  ffsfifo_reclaim(void *v)
  {
  	fifo_reclaim(v);
  	return (ffs_reclaim(v));
  }
  #endif
  