/* $NetBSD: nfs_bio.c,v 1.21 1995/07/24 21:20:46 cgd Exp $ */ /* * Copyright (c) 1989, 1993 * The Regents of the University of California. All rights reserved. * * This code is derived from software contributed to Berkeley by * Rick Macklem at The University of Guelph. * * 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. * * @(#)nfs_bio.c 8.5 (Berkeley) 1/4/94 */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include struct buf *incore(), *nfs_getcacheblk(); extern struct proc *nfs_iodwant[NFS_MAXASYNCDAEMON]; extern int nfs_numasync; /* * Vnode op for read using bio * Any similarity to readip() is purely coincidental */ nfs_bioread(vp, uio, ioflag, cred) register struct vnode *vp; register struct uio *uio; int ioflag; struct ucred *cred; { register struct nfsnode *np = VTONFS(vp); register int biosize, diff; struct buf *bp, *rabp; struct vattr vattr; struct proc *p; struct nfsmount *nmp; daddr_t lbn, bn, rabn; caddr_t baddr; int got_buf, nra, error = 0, n, on, not_readin; #ifdef lint ioflag = ioflag; #endif /* lint */ #ifdef DIAGNOSTIC if (uio->uio_rw != UIO_READ) panic("nfs_read mode"); #endif if (uio->uio_resid == 0) return (0); if (uio->uio_offset < 0 && vp->v_type != VDIR) return (EINVAL); nmp = VFSTONFS(vp->v_mount); biosize = nmp->nm_rsize; p = uio->uio_procp; /* * For nfs, cache consistency can only be maintained approximately. * Although RFC1094 does not specify the criteria, the following is * believed to be compatible with the reference port. * For nqnfs, full cache consistency is maintained within the loop. * For nfs: * If the file's modify time on the server has changed since the * last read rpc or you have written to the file, * you may have lost data cache consistency with the * server, so flush all of the file's data out of the cache. * Then force a getattr rpc to ensure that you have up to date * attributes. * The mount flag NFSMNT_MYWRITE says "Assume that my writes are * the ones changing the modify time. * NB: This implies that cache data can be read when up to * NFS_ATTRTIMEO seconds out of date. If you find that you need current * attributes this could be forced by setting n_attrstamp to 0 before * the VOP_GETATTR() call. */ if ((nmp->nm_flag & NFSMNT_NQNFS) == 0 && vp->v_type != VLNK) { if (np->n_flag & NMODIFIED) { if ((nmp->nm_flag & NFSMNT_MYWRITE) == 0 || vp->v_type != VREG) { if (error = nfs_vinvalbuf(vp, V_SAVE, cred, p, 1)) return (error); } np->n_attrstamp = 0; np->n_direofoffset = 0; if (error = VOP_GETATTR(vp, &vattr, cred, p)) return (error); np->n_mtime = vattr.va_mtime.ts_sec; } else { if (error = VOP_GETATTR(vp, &vattr, cred, p)) return (error); if (np->n_mtime != vattr.va_mtime.ts_sec) { np->n_direofoffset = 0; if (error = nfs_vinvalbuf(vp, V_SAVE, cred, p, 1)) return (error); np->n_mtime = vattr.va_mtime.ts_sec; } } } do { /* * Get a valid lease. If cached data is stale, flush it. */ if (nmp->nm_flag & NFSMNT_NQNFS) { if (NQNFS_CKINVALID(vp, np, NQL_READ)) { do { error = nqnfs_getlease(vp, NQL_READ, cred, p); } while (error == NQNFS_EXPIRED); if (error) return (error); if (np->n_lrev != np->n_brev || (np->n_flag & NQNFSNONCACHE) || ((np->n_flag & NMODIFIED) && vp->v_type == VDIR)) { if (vp->v_type == VDIR) { np->n_direofoffset = 0; cache_purge(vp); } if (error = nfs_vinvalbuf(vp, V_SAVE, cred, p, 1)) return (error); np->n_brev = np->n_lrev; } } else if (vp->v_type == VDIR && (np->n_flag & NMODIFIED)) { np->n_direofoffset = 0; cache_purge(vp); if (error = nfs_vinvalbuf(vp, V_SAVE, cred, p, 1)) return (error); } } /* * Don't cache magic amd symlinks. */ if (np->n_flag & NQNFSNONCACHE || ((vp->v_flag & VROOT) && vp->v_type == VLNK)) { switch (vp->v_type) { case VREG: error = nfs_readrpc(vp, uio, cred); break; case VLNK: error = nfs_readlinkrpc(vp, uio, cred); break; case VDIR: error = nfs_readdirrpc(vp, uio, cred); break; }; return (error); } baddr = (caddr_t)0; switch (vp->v_type) { case VREG: nfsstats.biocache_reads++; lbn = uio->uio_offset / biosize; on = uio->uio_offset & (biosize-1); bn = lbn * (biosize / DEV_BSIZE); not_readin = 1; /* * Start the read ahead(s), as required. */ if (nfs_numasync > 0 && nmp->nm_readahead > 0 && lbn == vp->v_lastr + 1) { for (nra = 0; nra < nmp->nm_readahead && (lbn + 1 + nra) * biosize < np->n_size; nra++) { rabn = (lbn + 1 + nra) * (biosize / DEV_BSIZE); if (!incore(vp, rabn)) { rabp = nfs_getcacheblk(vp, rabn, biosize, p); if (!rabp) return (EINTR); if ((rabp->b_flags & (B_DELWRI | B_DONE)) == 0) { rabp->b_flags |= (B_READ | B_ASYNC); if (nfs_asyncio(rabp, cred)) { rabp->b_flags |= B_INVAL; brelse(rabp); } } else brelse(rabp); } } } /* * If the block is in the cache and has the required data * in a valid region, just copy it out. * Otherwise, get the block and write back/read in, * as required. */ if ((bp = incore(vp, bn)) && (bp->b_flags & (B_BUSY | B_WRITEINPROG)) == (B_BUSY | B_WRITEINPROG)) got_buf = 0; else { again: bp = nfs_getcacheblk(vp, bn, biosize, p); if (!bp) return (EINTR); got_buf = 1; if ((bp->b_flags & (B_DONE | B_DELWRI)) == 0) { bp->b_flags |= B_READ; not_readin = 0; if (error = nfs_doio(bp, cred, p)) { brelse(bp); return (error); } } } n = min((unsigned)(biosize - on), uio->uio_resid); diff = np->n_size - uio->uio_offset; if (diff < n) n = diff; if (not_readin && n > 0) { if (on < bp->b_validoff || (on + n) > bp->b_validend) { if (!got_buf) { bp = nfs_getcacheblk(vp, bn, biosize, p); if (!bp) return (EINTR); got_buf = 1; } bp->b_flags |= B_INVAL; if (bp->b_dirtyend > 0) { if ((bp->b_flags & B_DELWRI) == 0) panic("nfsbioread"); if (VOP_BWRITE(bp) == EINTR) return (EINTR); } else brelse(bp); goto again; } } vp->v_lastr = lbn; diff = (on >= bp->b_validend) ? 0 : (bp->b_validend - on); if (diff < n) n = diff; break; case VLNK: nfsstats.biocache_readlinks++; bp = nfs_getcacheblk(vp, (daddr_t)0, NFS_MAXPATHLEN, p); if (!bp) return (EINTR); if ((bp->b_flags & B_DONE) == 0) { bp->b_flags |= B_READ; if (error = nfs_doio(bp, cred, p)) { brelse(bp); return (error); } } n = min(uio->uio_resid, NFS_MAXPATHLEN - bp->b_resid); got_buf = 1; on = 0; break; case VDIR: if (uio->uio_resid < NFS_DIRBLKSIZ) return (0); nfsstats.biocache_readdirs++; bn = (daddr_t)uio->uio_offset; bp = nfs_getcacheblk(vp, bn, NFS_DIRBLKSIZ, p); if (!bp) return (EINTR); if ((bp->b_flags & B_DONE) == 0) { bp->b_flags |= B_READ; if (error = nfs_doio(bp, cred, p)) { brelse(bp); return (error); } } /* * If not eof and read aheads are enabled, start one. * (You need the current block first, so that you have the * directory offset cookie of the next block. */ rabn = bp->b_blkno; if (nfs_numasync > 0 && nmp->nm_readahead > 0 && rabn != 0 && rabn != np->n_direofoffset && !incore(vp, rabn)) { rabp = nfs_getcacheblk(vp, rabn, NFS_DIRBLKSIZ, p); if (rabp) { if ((rabp->b_flags & (B_DONE | B_DELWRI)) == 0) { rabp->b_flags |= (B_READ | B_ASYNC); if (nfs_asyncio(rabp, cred)) { rabp->b_flags |= B_INVAL; brelse(rabp); } } else brelse(rabp); } } on = 0; n = min(uio->uio_resid, NFS_DIRBLKSIZ - bp->b_resid); got_buf = 1; break; }; if (n > 0) { if (!baddr) baddr = bp->b_data; error = uiomove(baddr + on, (int)n, uio); } switch (vp->v_type) { case VLNK: n = 0; break; case VDIR: uio->uio_offset = bp->b_blkno; break; }; if (got_buf) brelse(bp); } while (error == 0 && uio->uio_resid > 0 && n > 0); return (error); } /* * Vnode op for write using bio */ nfs_write(ap) struct vop_write_args /* { struct vnode *a_vp; struct uio *a_uio; int a_ioflag; struct ucred *a_cred; } */ *ap; { register int biosize; register struct uio *uio = ap->a_uio; struct proc *p = uio->uio_procp; register struct vnode *vp = ap->a_vp; struct nfsnode *np = VTONFS(vp); register struct ucred *cred = ap->a_cred; int ioflag = ap->a_ioflag; struct buf *bp; struct vattr vattr; struct nfsmount *nmp; daddr_t lbn, bn; int n, on, error = 0; #ifdef DIAGNOSTIC if (uio->uio_rw != UIO_WRITE) panic("nfs_write mode"); if (uio->uio_segflg == UIO_USERSPACE && uio->uio_procp != curproc) panic("nfs_write proc"); #endif if (vp->v_type != VREG) return (EIO); if (np->n_flag & NWRITEERR) { np->n_flag &= ~NWRITEERR; return (np->n_error); } if (ioflag & (IO_APPEND | IO_SYNC)) { if (np->n_flag & NMODIFIED) { np->n_attrstamp = 0; if (error = nfs_vinvalbuf(vp, V_SAVE, cred, p, 1)) return (error); } if (ioflag & IO_APPEND) { np->n_attrstamp = 0; if (error = VOP_GETATTR(vp, &vattr, cred, p)) return (error); uio->uio_offset = np->n_size; } } nmp = VFSTONFS(vp->v_mount); if (uio->uio_offset < 0) return (EINVAL); if (uio->uio_resid == 0) return (0); /* * Maybe this should be above the vnode op call, but so long as * file servers have no limits, i don't think it matters */ if (p && uio->uio_offset + uio->uio_resid > p->p_rlimit[RLIMIT_FSIZE].rlim_cur) { psignal(p, SIGXFSZ); return (EFBIG); } /* * I use nm_rsize, not nm_wsize so that all buffer cache blocks * will be the same size within a filesystem. nfs_writerpc will * still use nm_wsize when sizing the rpc's. */ biosize = nmp->nm_rsize; do { /* * XXX make sure we aren't cached in the VM page cache */ (void)vnode_pager_uncache(vp); /* * Check for a valid write lease. * If non-cachable, just do the rpc */ if ((nmp->nm_flag & NFSMNT_NQNFS) && NQNFS_CKINVALID(vp, np, NQL_WRITE)) { do { error = nqnfs_getlease(vp, NQL_WRITE, cred, p); } while (error == NQNFS_EXPIRED); if (error) return (error); if (np->n_lrev != np->n_brev || (np->n_flag & NQNFSNONCACHE)) { if (error = nfs_vinvalbuf(vp, V_SAVE, cred, p, 1)) return (error); np->n_brev = np->n_lrev; } } if (np->n_flag & NQNFSNONCACHE) return (nfs_writerpc(vp, uio, cred, ioflag)); nfsstats.biocache_writes++; lbn = uio->uio_offset / biosize; on = uio->uio_offset & (biosize-1); n = min((unsigned)(biosize - on), uio->uio_resid); bn = lbn * (biosize / DEV_BSIZE); again: bp = nfs_getcacheblk(vp, bn, biosize, p); if (!bp) return (EINTR); if (bp->b_wcred == NOCRED) { crhold(cred); bp->b_wcred = cred; } np->n_flag |= NMODIFIED; if (uio->uio_offset + n > np->n_size) { np->n_size = uio->uio_offset + n; vnode_pager_setsize(vp, (u_long)np->n_size); } /* * If the new write will leave a contiguous dirty * area, just update the b_dirtyoff and b_dirtyend, * otherwise force a write rpc of the old dirty area. */ if (bp->b_dirtyend > 0 && (on > bp->b_dirtyend || (on + n) < bp->b_dirtyoff)) { bp->b_proc = p; if (VOP_BWRITE(bp) == EINTR) return (EINTR); goto again; } /* * Check for valid write lease and get one as required. * In case getblk() and/or bwrite() delayed us. */ if ((nmp->nm_flag & NFSMNT_NQNFS) && NQNFS_CKINVALID(vp, np, NQL_WRITE)) { do { error = nqnfs_getlease(vp, NQL_WRITE, cred, p); } while (error == NQNFS_EXPIRED); if (error) { brelse(bp); return (error); } if (np->n_lrev != np->n_brev || (np->n_flag & NQNFSNONCACHE)) { brelse(bp); if (error = nfs_vinvalbuf(vp, V_SAVE, cred, p, 1)) return (error); np->n_brev = np->n_lrev; goto again; } } if (error = uiomove((char *)bp->b_data + on, n, uio)) { bp->b_flags |= B_ERROR; brelse(bp); return (error); } if (bp->b_dirtyend > 0) { bp->b_dirtyoff = min(on, bp->b_dirtyoff); bp->b_dirtyend = max((on + n), bp->b_dirtyend); } else { bp->b_dirtyoff = on; bp->b_dirtyend = on + n; } #ifndef notdef if (bp->b_validend == 0 || bp->b_validend < bp->b_dirtyoff || bp->b_validoff > bp->b_dirtyend) { bp->b_validoff = bp->b_dirtyoff; bp->b_validend = bp->b_dirtyend; } else { bp->b_validoff = min(bp->b_validoff, bp->b_dirtyoff); bp->b_validend = max(bp->b_validend, bp->b_dirtyend); } #else bp->b_validoff = bp->b_dirtyoff; bp->b_validend = bp->b_dirtyend; #endif if (ioflag & IO_APPEND) bp->b_flags |= B_APPENDWRITE; /* * If the lease is non-cachable or IO_SYNC do bwrite(). */ if ((np->n_flag & NQNFSNONCACHE) || (ioflag & IO_SYNC)) { bp->b_proc = p; if (error = VOP_BWRITE(bp)) return (error); } else if ((n + on) == biosize && (nmp->nm_flag & NFSMNT_NQNFS) == 0) { bp->b_proc = (struct proc *)0; bawrite(bp); } else bdwrite(bp); } while (uio->uio_resid > 0 && n > 0); return (0); } /* * Get an nfs cache block. * Allocate a new one if the block isn't currently in the cache * and return the block marked busy. If the calling process is * interrupted by a signal for an interruptible mount point, return * NULL. */ struct buf * nfs_getcacheblk(vp, bn, size, p) struct vnode *vp; daddr_t bn; int size; struct proc *p; { register struct buf *bp; struct nfsmount *nmp = VFSTONFS(vp->v_mount); if (nmp->nm_flag & NFSMNT_INT) { bp = getblk(vp, bn, size, PCATCH, 0); while (bp == (struct buf *)0) { if (nfs_sigintr(nmp, (struct nfsreq *)0, p)) return ((struct buf *)0); bp = getblk(vp, bn, size, 0, 2 * hz); } } else bp = getblk(vp, bn, size, 0, 0); return (bp); } /* * Flush and invalidate all dirty buffers. If another process is already * doing the flush, just wait for completion. */ nfs_vinvalbuf(vp, flags, cred, p, intrflg) struct vnode *vp; int flags; struct ucred *cred; struct proc *p; int intrflg; { register struct nfsnode *np = VTONFS(vp); struct nfsmount *nmp = VFSTONFS(vp->v_mount); int error = 0, slpflag, slptimeo; if ((nmp->nm_flag & NFSMNT_INT) == 0) intrflg = 0; if (intrflg) { slpflag = PCATCH; slptimeo = 2 * hz; } else { slpflag = 0; slptimeo = 0; } /* * First wait for any other process doing a flush to complete. */ while (np->n_flag & NFLUSHINPROG) { np->n_flag |= NFLUSHWANT; error = tsleep((caddr_t)&np->n_flag, PRIBIO + 2, "nfsvinval", slptimeo); if (error && intrflg && nfs_sigintr(nmp, (struct nfsreq *)0, p)) return (EINTR); } /* * Now, flush as required. */ np->n_flag |= NFLUSHINPROG; error = vinvalbuf(vp, flags, cred, p, slpflag, 0); while (error) { if (intrflg && nfs_sigintr(nmp, (struct nfsreq *)0, p)) { np->n_flag &= ~NFLUSHINPROG; if (np->n_flag & NFLUSHWANT) { np->n_flag &= ~NFLUSHWANT; wakeup((caddr_t)&np->n_flag); } return (EINTR); } error = vinvalbuf(vp, flags, cred, p, 0, slptimeo); } np->n_flag &= ~(NMODIFIED | NFLUSHINPROG); if (np->n_flag & NFLUSHWANT) { np->n_flag &= ~NFLUSHWANT; wakeup((caddr_t)&np->n_flag); } return (0); } /* * Initiate asynchronous I/O. Return an error if no nfsiods are available. * This is mainly to avoid queueing async I/O requests when the nfsiods * are all hung on a dead server. */ nfs_asyncio(bp, cred) register struct buf *bp; struct ucred *cred; { register int i; if (nfs_numasync == 0) return (EIO); for (i = 0; i < NFS_MAXASYNCDAEMON; i++) if (nfs_iodwant[i]) { if (bp->b_flags & B_READ) { if (bp->b_rcred == NOCRED && cred != NOCRED) { crhold(cred); bp->b_rcred = cred; } } else { if (bp->b_wcred == NOCRED && cred != NOCRED) { crhold(cred); bp->b_wcred = cred; } } TAILQ_INSERT_TAIL(&nfs_bufq, bp, b_freelist); nfs_iodwant[i] = (struct proc *)0; wakeup((caddr_t)&nfs_iodwant[i]); return (0); } return (EIO); } /* * Do an I/O operation to/from a cache block. This may be called * synchronously or from an nfsiod. */ int nfs_doio(bp, cr, p) register struct buf *bp; struct cred *cr; struct proc *p; { register struct uio *uiop; register struct vnode *vp; struct nfsnode *np; struct nfsmount *nmp; int error, diff, len; struct uio uio; struct iovec io; vp = bp->b_vp; np = VTONFS(vp); nmp = VFSTONFS(vp->v_mount); uiop = &uio; uiop->uio_iov = &io; uiop->uio_iovcnt = 1; uiop->uio_segflg = UIO_SYSSPACE; uiop->uio_procp = p; /* * Historically, paging was done with physio, but no more... */ if (bp->b_flags & B_PHYS) { /* * ...though reading /dev/drum still gets us here. */ io.iov_len = uiop->uio_resid = bp->b_bcount; /* mapping was done by vmapbuf() */ io.iov_base = bp->b_data; uiop->uio_offset = bp->b_blkno * DEV_BSIZE; if (bp->b_flags & B_READ) { uiop->uio_rw = UIO_READ; nfsstats.read_physios++; error = nfs_readrpc(vp, uiop, cr); } else { uiop->uio_rw = UIO_WRITE; nfsstats.write_physios++; error = nfs_writerpc(vp, uiop, cr, 0); } if (error) { bp->b_flags |= B_ERROR; bp->b_error = error; } } else if (bp->b_flags & B_READ) { io.iov_len = uiop->uio_resid = bp->b_bcount; io.iov_base = bp->b_data; uiop->uio_rw = UIO_READ; switch (vp->v_type) { case VREG: uiop->uio_offset = bp->b_blkno * DEV_BSIZE; nfsstats.read_bios++; error = nfs_readrpc(vp, uiop, cr); if (!error) { bp->b_validoff = 0; if (uiop->uio_resid) { /* * If len > 0, there is a hole in the file and * no writes after the hole have been pushed to * the server yet. * Just zero fill the rest of the valid area. */ diff = bp->b_bcount - uiop->uio_resid; len = np->n_size - (bp->b_blkno * DEV_BSIZE + diff); if (len > 0) { len = min(len, uiop->uio_resid); bzero((char *)bp->b_data + diff, len); bp->b_validend = diff + len; } else bp->b_validend = diff; } else bp->b_validend = bp->b_bcount; } if (p && (vp->v_flag & VTEXT) && (((nmp->nm_flag & NFSMNT_NQNFS) && NQNFS_CKINVALID(vp, np, NQL_READ) && np->n_lrev != np->n_brev) || (!(nmp->nm_flag & NFSMNT_NQNFS) && np->n_mtime != np->n_vattr.va_mtime.ts_sec))) { uprintf("Process killed due to text file modification\n"); psignal(p, SIGKILL); p->p_holdcnt++; } break; case VLNK: uiop->uio_offset = 0; nfsstats.readlink_bios++; error = nfs_readlinkrpc(vp, uiop, cr); break; case VDIR: uiop->uio_offset = bp->b_lblkno; nfsstats.readdir_bios++; if (VFSTONFS(vp->v_mount)->nm_flag & NFSMNT_NQNFS) error = nfs_readdirlookrpc(vp, uiop, cr); else error = nfs_readdirrpc(vp, uiop, cr); /* * Save offset cookie in b_blkno. */ bp->b_blkno = uiop->uio_offset; break; }; if (error) { bp->b_flags |= B_ERROR; bp->b_error = error; } } else { io.iov_len = uiop->uio_resid = bp->b_dirtyend - bp->b_dirtyoff; uiop->uio_offset = (bp->b_blkno * DEV_BSIZE) + bp->b_dirtyoff; io.iov_base = (char *)bp->b_data + bp->b_dirtyoff; uiop->uio_rw = UIO_WRITE; nfsstats.write_bios++; if (bp->b_flags & B_APPENDWRITE) error = nfs_writerpc(vp, uiop, cr, IO_APPEND); else error = nfs_writerpc(vp, uiop, cr, 0); bp->b_flags &= ~(B_WRITEINPROG | B_APPENDWRITE); /* * For an interrupted write, the buffer is still valid and the * write hasn't been pushed to the server yet, so we can't set * B_ERROR and report the interruption by setting B_EINTR. For * the B_ASYNC case, B_EINTR is not relevant, so the rpc attempt * is essentially a noop. */ if (error == EINTR) { bp->b_flags &= ~B_INVAL; bp->b_flags |= B_DELWRI; /* * Since for the B_ASYNC case, nfs_bwrite() has reassigned the * buffer to the clean list, we have to reassign it back to the * dirty one. Ugh. */ if (bp->b_flags & B_ASYNC) reassignbuf(bp, vp); else bp->b_flags |= B_EINTR; } else { if (error) { bp->b_flags |= B_ERROR; bp->b_error = np->n_error = error; np->n_flag |= NWRITEERR; } bp->b_dirtyoff = bp->b_dirtyend = 0; } } bp->b_resid = uiop->uio_resid; biodone(bp); return (error); }