sys/ufs/ext2fs/ext2fs_readwrite.c

   1 /*      $NetBSD: ext2fs_readwrite.c,v 1.58 2011/11/18 21:18:51 christos Exp $   */
   2
   3 /*-
   4  * Copyright (c) 1993
   5  *      The Regents of the University of California.  All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  * 3. Neither the name of the University nor the names of its contributors
  16  *    may be used to endorse or promote products derived from this software
  17  *    without specific prior written permission.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  29  * SUCH DAMAGE.
  30  *
  31  *      @(#)ufs_readwrite.c     8.8 (Berkeley) 8/4/94
  32  * Modified for ext2fs by Manuel Bouyer.
  33  */
  34
  35 /*-
  36  * Copyright (c) 1997 Manuel Bouyer.
  37  *
  38  * Redistribution and use in source and binary forms, with or without
  39  * modification, are permitted provided that the following conditions
  40  * are met:
  41  * 1. Redistributions of source code must retain the above copyright
  42  *    notice, this list of conditions and the following disclaimer.
  43  * 2. Redistributions in binary form must reproduce the above copyright
  44  *    notice, this list of conditions and the following disclaimer in the
  45  *    documentation and/or other materials provided with the distribution.
  46  *
  47  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  48  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  49  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  50  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  51  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  52  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  53  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  54  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  55  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  56  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  57  *
  58  *      @(#)ufs_readwrite.c     8.8 (Berkeley) 8/4/94
  59  * Modified for ext2fs by Manuel Bouyer.
  60  */
  61
  62 #include <sys/cdefs.h>
  63 __KERNEL_RCSID(0, "$NetBSD: ext2fs_readwrite.c,v 1.58 2011/11/18 21:18:51 christos Exp $");
  64
  65 #include <sys/param.h>
  66 #include <sys/systm.h>
  67 #include <sys/resourcevar.h>
  68 #include <sys/kernel.h>
  69 #include <sys/file.h>
  70 #include <sys/stat.h>
  71 #include <sys/buf.h>
  72 #include <sys/proc.h>
  73 #include <sys/mount.h>
  74 #include <sys/vnode.h>
  75 #include <sys/malloc.h>
  76 #include <sys/signalvar.h>
  77 #include <sys/kauth.h>
  78
  79 #include <ufs/ufs/inode.h>
  80 #include <ufs/ufs/ufsmount.h>
  81 #include <ufs/ufs/ufs_extern.h>
  82 #include <ufs/ext2fs/ext2fs.h>
  83 #include <ufs/ext2fs/ext2fs_extern.h>
  84
  85
  86 #define doclusterread 0 /* XXX underway */
  87 #define doclusterwrite 0
  88
  89 /*
  90  * Vnode op for reading.
  91  */
  92 /* ARGSUSED */
  93 int
  94 ext2fs_read(void *v)
  95 {
  96         struct vop_read_args /* {
  97                 struct vnode *a_vp;
  98                 struct uio *a_uio;
  99                 int a_ioflag;
 100                 kauth_cred_t a_cred;
 101         } */ *ap = v;
 102         struct vnode *vp;
 103         struct inode *ip;
 104         struct uio *uio;
 105         struct m_ext2fs *fs;
 106         struct buf *bp;
 107         struct ufsmount *ump;
 108         vsize_t bytelen;
 109         daddr_t lbn, nextlbn;
 110         off_t bytesinfile;
 111         long size, xfersize, blkoffset;
 112         int error;
 113
 114         vp = ap->a_vp;
 115         ip = VTOI(vp);
 116         ump = ip->i_ump;
 117         uio = ap->a_uio;
 118         error = 0;
 119
 120 #ifdef DIAGNOSTIC
 121         if (uio->uio_rw != UIO_READ)
 122                 panic("%s: mode", "ext2fs_read");
 123
 124         if (vp->v_type == VLNK) {
 125                 if (ext2fs_size(ip) < ump->um_maxsymlinklen ||
 126                     (ump->um_maxsymlinklen == 0 && ip->i_e2fs_nblock == 0))
 127                         panic("%s: short symlink", "ext2fs_read");
 128         } else if (vp->v_type != VREG && vp->v_type != VDIR)
 129                 panic("%s: type %d", "ext2fs_read", vp->v_type);
 130 #endif
 131         fs = ip->i_e2fs;
 132         if ((uint64_t)uio->uio_offset > ump->um_maxfilesize)
 133                 return (EFBIG);
 134         if (uio->uio_resid == 0)
 135                 return (0);
 136         if (uio->uio_offset >= ext2fs_size(ip))
 137                 goto out;
 138
 139         if (vp->v_type == VREG) {
 140                 const int advice = IO_ADV_DECODE(ap->a_ioflag);
 141
 142                 while (uio->uio_resid > 0) {
 143                         bytelen = MIN(ext2fs_size(ip) - uio->uio_offset,
 144                             uio->uio_resid);
 145                         if (bytelen == 0)
 146                                 break;
 147
 148                         error = ubc_uiomove(&vp->v_uobj, uio, bytelen, advice,
 149                             UBC_READ | UBC_PARTIALOK | UBC_UNMAP_FLAG(vp));
 150                         if (error)
 151                                 break;
 152                 }
 153                 goto out;
 154         }
 155
 156         for (error = 0, bp = NULL; uio->uio_resid > 0; bp = NULL) {
 157                 bytesinfile = ext2fs_size(ip) - uio->uio_offset;
 158                 if (bytesinfile <= 0)
 159                         break;
 160                 lbn = lblkno(fs, uio->uio_offset);
 161                 nextlbn = lbn + 1;
 162                 size = fs->e2fs_bsize;
 163                 blkoffset = blkoff(fs, uio->uio_offset);
 164                 xfersize = fs->e2fs_bsize - blkoffset;
 165                 if (uio->uio_resid < xfersize)
 166                         xfersize = uio->uio_resid;
 167                 if (bytesinfile < xfersize)
 168                         xfersize = bytesinfile;
 169
 170                 if (lblktosize(fs, nextlbn) >= ext2fs_size(ip))
 171                         error = bread(vp, lbn, size, NOCRED, 0, &bp);
 172                 else {
 173                         int nextsize = fs->e2fs_bsize;
 174                         error = breadn(vp, lbn,
 175                                 size, &nextlbn, &nextsize, 1, NOCRED, 0, &bp);
 176                 }
 177                 if (error)
 178                         break;
 179
 180                 /*
 181                  * We should only get non-zero b_resid when an I/O error
 182                  * has occurred, which should cause us to break above.
 183                  * However, if the short read did not cause an error,
 184                  * then we want to ensure that we do not uiomove bad
 185                  * or uninitialized data.
 186                  */
 187                 size -= bp->b_resid;
 188                 if (size < xfersize) {
 189                         if (size == 0)
 190                                 break;
 191                         xfersize = size;
 192                 }
 193                 error = uiomove((char *)bp->b_data + blkoffset, xfersize, uio);
 194                 if (error)
 195                         break;
 196                 brelse(bp, 0);
 197         }
 198         if (bp != NULL)
 199                 brelse(bp, 0);
 200
 201 out:
 202         if (!(vp->v_mount->mnt_flag & MNT_NOATIME)) {
 203                 ip->i_flag |= IN_ACCESS;
 204                 if ((ap->a_ioflag & IO_SYNC) == IO_SYNC)
 205                         error = ext2fs_update(vp, NULL, NULL, UPDATE_WAIT);
 206         }
 207         return (error);
 208 }
 209
 210 /*
 211  * Vnode op for writing.
 212  */
 213 int
 214 ext2fs_write(void *v)
 215 {
 216         struct vop_write_args /* {
 217                 struct vnode *a_vp;
 218                 struct uio *a_uio;
 219                 int a_ioflag;
 220                 kauth_cred_t a_cred;
 221         } */ *ap = v;
 222         struct vnode *vp;
 223         struct uio *uio;
 224         struct inode *ip;
 225         struct m_ext2fs *fs;
 226         struct buf *bp;
 227         struct ufsmount *ump;
 228         daddr_t lbn;
 229         off_t osize;
 230         int blkoffset, error, flags, ioflag, resid, xfersize;
 231         vsize_t bytelen;
 232         off_t oldoff = 0;                                       /* XXX */
 233         bool async;
 234         int extended = 0;
 235         int advice;
 236
 237         ioflag = ap->a_ioflag;
 238         advice = IO_ADV_DECODE(ioflag);
 239         uio = ap->a_uio;
 240         vp = ap->a_vp;
 241         ip = VTOI(vp);
 242         ump = ip->i_ump;
 243         error = 0;
 244
 245 #ifdef DIAGNOSTIC
 246         if (uio->uio_rw != UIO_WRITE)
 247                 panic("%s: mode", "ext2fs_write");
 248 #endif
 249
 250         switch (vp->v_type) {
 251         case VREG:
 252                 if (ioflag & IO_APPEND)
 253                         uio->uio_offset = ext2fs_size(ip);
 254                 if ((ip->i_e2fs_flags & EXT2_APPEND) &&
 255                     uio->uio_offset != ext2fs_size(ip))
 256                         return (EPERM);
 257                 /* FALLTHROUGH */
 258         case VLNK:
 259                 break;
 260         case VDIR:
 261                 if ((ioflag & IO_SYNC) == 0)
 262                         panic("%s: nonsync dir write", "ext2fs_write");
 263                 break;
 264         default:
 265                 panic("%s: type", "ext2fs_write");
 266         }
 267
 268         fs = ip->i_e2fs;
 269         if (uio->uio_offset < 0 ||
 270             (uint64_t)uio->uio_offset + uio->uio_resid > ump->um_maxfilesize)
 271                 return (EFBIG);
 272         if (uio->uio_resid == 0)
 273                 return (0);
 274
 275         async = vp->v_mount->mnt_flag & MNT_ASYNC;
 276         resid = uio->uio_resid;
 277         osize = ext2fs_size(ip);
 278
 279         if (vp->v_type == VREG) {
 280                 while (uio->uio_resid > 0) {
 281                         oldoff = uio->uio_offset;
 282                         blkoffset = blkoff(fs, uio->uio_offset);
 283                         bytelen = MIN(fs->e2fs_bsize - blkoffset,
 284                             uio->uio_resid);
 285
 286                         if (vp->v_size < oldoff + bytelen) {
 287                                 uvm_vnp_setwritesize(vp, oldoff + bytelen);
 288                         }
 289                         error = ufs_balloc_range(vp, uio->uio_offset,
 290                             bytelen, ap->a_cred, 0);
 291                         if (error)
 292                                 break;
 293                         error = ubc_uiomove(&vp->v_uobj, uio, bytelen, advice,
 294                             UBC_WRITE | UBC_UNMAP_FLAG(vp));
 295                         if (error)
 296                                 break;
 297
 298                         /*
 299                          * update UVM's notion of the size now that we've
 300                          * copied the data into the vnode's pages.
 301                          */
 302
 303                         if (vp->v_size < uio->uio_offset) {
 304                                 uvm_vnp_setsize(vp, uio->uio_offset);
 305                                 extended = 1;
 306                         }
 307
 308                         /*
 309                          * flush what we just wrote if necessary.
 310                          * XXXUBC simplistic async flushing.
 311                          */
 312
 313                         if (!async && oldoff >> 16 != uio->uio_offset >> 16) {
 314                                 mutex_enter(vp->v_interlock);
 315                                 error = VOP_PUTPAGES(vp, (oldoff >> 16) << 16,
 316                                     (uio->uio_offset >> 16) << 16, PGO_CLEANIT);
 317                         }
 318                 }
 319                 if (error == 0 && ioflag & IO_SYNC) {
 320                         mutex_enter(vp->v_interlock);
 321                         error = VOP_PUTPAGES(vp, trunc_page(oldoff),
 322                             round_page(blkroundup(fs, uio->uio_offset)),
 323                             PGO_CLEANIT | PGO_SYNCIO);
 324                 }
 325
 326                 goto out;
 327         }
 328
 329         flags = ioflag & IO_SYNC ? B_SYNC : 0;
 330         for (error = 0; uio->uio_resid > 0;) {
 331                 lbn = lblkno(fs, uio->uio_offset);
 332                 blkoffset = blkoff(fs, uio->uio_offset);
 333                 xfersize = MIN(fs->e2fs_bsize - blkoffset, uio->uio_resid);
 334                 if (xfersize < fs->e2fs_bsize)
 335                         flags |= B_CLRBUF;
 336                 else
 337                         flags &= ~B_CLRBUF;
 338                 error = ext2fs_balloc(ip,
 339                     lbn, blkoffset + xfersize, ap->a_cred, &bp, flags);
 340                 if (error)
 341                         break;
 342                 if (ext2fs_size(ip) < uio->uio_offset + xfersize) {
 343                         error = ext2fs_setsize(ip, uio->uio_offset + xfersize);
 344                         if (error)
 345                                 break;
 346                 }
 347                 error = uiomove((char *)bp->b_data + blkoffset, xfersize, uio);
 348
 349                 /*
 350                  * update UVM's notion of the size now that we've
 351                  * copied the data into the vnode's pages.
 352                  */
 353
 354                 if (vp->v_size < uio->uio_offset) {
 355                         uvm_vnp_setsize(vp, uio->uio_offset);
 356                         extended = 1;
 357                 }
 358
 359                 if (ioflag & IO_SYNC)
 360                         (void)bwrite(bp);
 361                 else if (xfersize + blkoffset == fs->e2fs_bsize)
 362                         bawrite(bp);
 363                 else
 364                         bdwrite(bp);
 365                 if (error || xfersize == 0)
 366                         break;
 367         }
 368
 369         /*
 370          * If we successfully wrote any data, and we are not the superuser
 371          * we clear the setuid and setgid bits as a precaution against
 372          * tampering.
 373          */
 374
 375 out:
 376         ip->i_flag |= IN_CHANGE | IN_UPDATE;
 377         if (vp->v_mount->mnt_flag & MNT_RELATIME)
 378                 ip->i_flag |= IN_ACCESS;
 379         if (resid > uio->uio_resid && ap->a_cred &&
 380             kauth_authorize_generic(ap->a_cred, KAUTH_GENERIC_ISSUSER, NULL))
 381                 ip->i_e2fs_mode &= ~(ISUID | ISGID);
 382         if (resid > uio->uio_resid)
 383                 VN_KNOTE(vp, NOTE_WRITE | (extended ? NOTE_EXTEND : 0));
 384         if (error) {
 385                 (void) ext2fs_truncate(vp, osize, ioflag & IO_SYNC, ap->a_cred);
 386                 uio->uio_offset -= resid - uio->uio_resid;
 387                 uio->uio_resid = resid;
 388         } else if (resid > uio->uio_resid && (ioflag & IO_SYNC) == IO_SYNC)
 389                 error = ext2fs_update(vp, NULL, NULL, UPDATE_WAIT);
 390         KASSERT(vp->v_size == ext2fs_size(ip));
 391         return (error);
 392 }