The Design and Implementation of the FreeBSD Operating System, Second Edition
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FreeBSD/Linux Kernel Cross Reference
sys/kern/vfs_default.c

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    1 /*-
    2  * Copyright (c) 1989, 1993
    3  *      The Regents of the University of California.  All rights reserved.
    4  *
    5  * This code is derived from software contributed
    6  * to Berkeley by John Heidemann of the UCLA Ficus project.
    7  *
    8  * Source: * @(#)i405_init.c 2.10 92/04/27 UCLA Ficus project
    9  *
   10  * Redistribution and use in source and binary forms, with or without
   11  * modification, are permitted provided that the following conditions
   12  * are met:
   13  * 1. Redistributions of source code must retain the above copyright
   14  *    notice, this list of conditions and the following disclaimer.
   15  * 2. Redistributions in binary form must reproduce the above copyright
   16  *    notice, this list of conditions and the following disclaimer in the
   17  *    documentation and/or other materials provided with the distribution.
   18  * 4. Neither the name of the University nor the names of its contributors
   19  *    may be used to endorse or promote products derived from this software
   20  *    without specific prior written permission.
   21  *
   22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   32  * SUCH DAMAGE.
   33  */
   34 
   35 #include <sys/cdefs.h>
   36 __FBSDID("$FreeBSD: stable/10/sys/kern/vfs_default.c 330266 2018-03-02 04:43:07Z mckusick $");
   37 
   38 #include <sys/param.h>
   39 #include <sys/systm.h>
   40 #include <sys/bio.h>
   41 #include <sys/buf.h>
   42 #include <sys/conf.h>
   43 #include <sys/event.h>
   44 #include <sys/kernel.h>
   45 #include <sys/limits.h>
   46 #include <sys/lock.h>
   47 #include <sys/lockf.h>
   48 #include <sys/malloc.h>
   49 #include <sys/mount.h>
   50 #include <sys/namei.h>
   51 #include <sys/rwlock.h>
   52 #include <sys/fcntl.h>
   53 #include <sys/unistd.h>
   54 #include <sys/vnode.h>
   55 #include <sys/dirent.h>
   56 #include <sys/poll.h>
   57 
   58 #include <security/mac/mac_framework.h>
   59 
   60 #include <vm/vm.h>
   61 #include <vm/vm_object.h>
   62 #include <vm/vm_extern.h>
   63 #include <vm/pmap.h>
   64 #include <vm/vm_map.h>
   65 #include <vm/vm_page.h>
   66 #include <vm/vm_pager.h>
   67 #include <vm/vnode_pager.h>
   68 
   69 static int      vop_nolookup(struct vop_lookup_args *);
   70 static int      vop_norename(struct vop_rename_args *);
   71 static int      vop_nostrategy(struct vop_strategy_args *);
   72 static int      get_next_dirent(struct vnode *vp, struct dirent **dpp,
   73                                 char *dirbuf, int dirbuflen, off_t *off,
   74                                 char **cpos, int *len, int *eofflag,
   75                                 struct thread *td);
   76 static int      dirent_exists(struct vnode *vp, const char *dirname,
   77                               struct thread *td);
   78 
   79 #define DIRENT_MINSIZE (sizeof(struct dirent) - (MAXNAMLEN+1) + 4)
   80 
   81 static int vop_stdis_text(struct vop_is_text_args *ap);
   82 static int vop_stdset_text(struct vop_set_text_args *ap);
   83 static int vop_stdunset_text(struct vop_unset_text_args *ap);
   84 static int vop_stdget_writecount(struct vop_get_writecount_args *ap);
   85 static int vop_stdadd_writecount(struct vop_add_writecount_args *ap);
   86 
   87 /*
   88  * This vnode table stores what we want to do if the filesystem doesn't
   89  * implement a particular VOP.
   90  *
   91  * If there is no specific entry here, we will return EOPNOTSUPP.
   92  *
   93  * Note that every filesystem has to implement either vop_access
   94  * or vop_accessx; failing to do so will result in immediate crash
   95  * due to stack overflow, as vop_stdaccess() calls vop_stdaccessx(),
   96  * which calls vop_stdaccess() etc.
   97  */
   98 
   99 struct vop_vector default_vnodeops = {
  100         .vop_default =          NULL,
  101         .vop_bypass =           VOP_EOPNOTSUPP,
  102 
  103         .vop_access =           vop_stdaccess,
  104         .vop_accessx =          vop_stdaccessx,
  105         .vop_advise =           vop_stdadvise,
  106         .vop_advlock =          vop_stdadvlock,
  107         .vop_advlockasync =     vop_stdadvlockasync,
  108         .vop_advlockpurge =     vop_stdadvlockpurge,
  109         .vop_allocate =         vop_stdallocate,
  110         .vop_bmap =             vop_stdbmap,
  111         .vop_close =            VOP_NULL,
  112         .vop_fsync =            VOP_NULL,
  113         .vop_getpages =         vop_stdgetpages,
  114         .vop_getwritemount =    vop_stdgetwritemount,
  115         .vop_inactive =         VOP_NULL,
  116         .vop_ioctl =            VOP_ENOTTY,
  117         .vop_kqfilter =         vop_stdkqfilter,
  118         .vop_islocked =         vop_stdislocked,
  119         .vop_lock1 =            vop_stdlock,
  120         .vop_lookup =           vop_nolookup,
  121         .vop_open =             VOP_NULL,
  122         .vop_pathconf =         VOP_EINVAL,
  123         .vop_poll =             vop_nopoll,
  124         .vop_putpages =         vop_stdputpages,
  125         .vop_readlink =         VOP_EINVAL,
  126         .vop_rename =           vop_norename,
  127         .vop_revoke =           VOP_PANIC,
  128         .vop_strategy =         vop_nostrategy,
  129         .vop_unlock =           vop_stdunlock,
  130         .vop_vptocnp =          vop_stdvptocnp,
  131         .vop_vptofh =           vop_stdvptofh,
  132         .vop_unp_bind =         vop_stdunp_bind,
  133         .vop_unp_connect =      vop_stdunp_connect,
  134         .vop_unp_detach =       vop_stdunp_detach,
  135         .vop_is_text =          vop_stdis_text,
  136         .vop_set_text =         vop_stdset_text,
  137         .vop_unset_text =       vop_stdunset_text,
  138         .vop_get_writecount =   vop_stdget_writecount,
  139         .vop_add_writecount =   vop_stdadd_writecount,
  140 };
  141 
  142 /*
  143  * Series of placeholder functions for various error returns for
  144  * VOPs.
  145  */
  146 
  147 int
  148 vop_eopnotsupp(struct vop_generic_args *ap)
  149 {
  150         /*
  151         printf("vop_notsupp[%s]\n", ap->a_desc->vdesc_name);
  152         */
  153 
  154         return (EOPNOTSUPP);
  155 }
  156 
  157 int
  158 vop_ebadf(struct vop_generic_args *ap)
  159 {
  160 
  161         return (EBADF);
  162 }
  163 
  164 int
  165 vop_enotty(struct vop_generic_args *ap)
  166 {
  167 
  168         return (ENOTTY);
  169 }
  170 
  171 int
  172 vop_einval(struct vop_generic_args *ap)
  173 {
  174 
  175         return (EINVAL);
  176 }
  177 
  178 int
  179 vop_enoent(struct vop_generic_args *ap)
  180 {
  181 
  182         return (ENOENT);
  183 }
  184 
  185 int
  186 vop_null(struct vop_generic_args *ap)
  187 {
  188 
  189         return (0);
  190 }
  191 
  192 /*
  193  * Helper function to panic on some bad VOPs in some filesystems.
  194  */
  195 int
  196 vop_panic(struct vop_generic_args *ap)
  197 {
  198 
  199         panic("filesystem goof: vop_panic[%s]", ap->a_desc->vdesc_name);
  200 }
  201 
  202 /*
  203  * vop_std<something> and vop_no<something> are default functions for use by
  204  * filesystems that need the "default reasonable" implementation for a
  205  * particular operation.
  206  *
  207  * The documentation for the operations they implement exists (if it exists)
  208  * in the VOP_<SOMETHING>(9) manpage (all uppercase).
  209  */
  210 
  211 /*
  212  * Default vop for filesystems that do not support name lookup
  213  */
  214 static int
  215 vop_nolookup(ap)
  216         struct vop_lookup_args /* {
  217                 struct vnode *a_dvp;
  218                 struct vnode **a_vpp;
  219                 struct componentname *a_cnp;
  220         } */ *ap;
  221 {
  222 
  223         *ap->a_vpp = NULL;
  224         return (ENOTDIR);
  225 }
  226 
  227 /*
  228  * vop_norename:
  229  *
  230  * Handle unlock and reference counting for arguments of vop_rename
  231  * for filesystems that do not implement rename operation.
  232  */
  233 static int
  234 vop_norename(struct vop_rename_args *ap)
  235 {
  236 
  237         vop_rename_fail(ap);
  238         return (EOPNOTSUPP);
  239 }
  240 
  241 /*
  242  *      vop_nostrategy:
  243  *
  244  *      Strategy routine for VFS devices that have none.
  245  *
  246  *      BIO_ERROR and B_INVAL must be cleared prior to calling any strategy
  247  *      routine.  Typically this is done for a BIO_READ strategy call.
  248  *      Typically B_INVAL is assumed to already be clear prior to a write
  249  *      and should not be cleared manually unless you just made the buffer
  250  *      invalid.  BIO_ERROR should be cleared either way.
  251  */
  252 
  253 static int
  254 vop_nostrategy (struct vop_strategy_args *ap)
  255 {
  256         printf("No strategy for buffer at %p\n", ap->a_bp);
  257         vprint("vnode", ap->a_vp);
  258         ap->a_bp->b_ioflags |= BIO_ERROR;
  259         ap->a_bp->b_error = EOPNOTSUPP;
  260         bufdone(ap->a_bp);
  261         return (EOPNOTSUPP);
  262 }
  263 
  264 static int
  265 get_next_dirent(struct vnode *vp, struct dirent **dpp, char *dirbuf,
  266                 int dirbuflen, off_t *off, char **cpos, int *len,
  267                 int *eofflag, struct thread *td)
  268 {
  269         int error, reclen;
  270         struct uio uio;
  271         struct iovec iov;
  272         struct dirent *dp;
  273 
  274         KASSERT(VOP_ISLOCKED(vp), ("vp %p is not locked", vp));
  275         KASSERT(vp->v_type == VDIR, ("vp %p is not a directory", vp));
  276 
  277         if (*len == 0) {
  278                 iov.iov_base = dirbuf;
  279                 iov.iov_len = dirbuflen;
  280 
  281                 uio.uio_iov = &iov;
  282                 uio.uio_iovcnt = 1;
  283                 uio.uio_offset = *off;
  284                 uio.uio_resid = dirbuflen;
  285                 uio.uio_segflg = UIO_SYSSPACE;
  286                 uio.uio_rw = UIO_READ;
  287                 uio.uio_td = td;
  288 
  289                 *eofflag = 0;
  290 
  291 #ifdef MAC
  292                 error = mac_vnode_check_readdir(td->td_ucred, vp);
  293                 if (error == 0)
  294 #endif
  295                         error = VOP_READDIR(vp, &uio, td->td_ucred, eofflag,
  296                                 NULL, NULL);
  297                 if (error)
  298                         return (error);
  299 
  300                 *off = uio.uio_offset;
  301 
  302                 *cpos = dirbuf;
  303                 *len = (dirbuflen - uio.uio_resid);
  304 
  305                 if (*len == 0)
  306                         return (ENOENT);
  307         }
  308 
  309         dp = (struct dirent *)(*cpos);
  310         reclen = dp->d_reclen;
  311         *dpp = dp;
  312 
  313         /* check for malformed directory.. */
  314         if (reclen < DIRENT_MINSIZE)
  315                 return (EINVAL);
  316 
  317         *cpos += reclen;
  318         *len -= reclen;
  319 
  320         return (0);
  321 }
  322 
  323 /*
  324  * Check if a named file exists in a given directory vnode.
  325  */
  326 static int
  327 dirent_exists(struct vnode *vp, const char *dirname, struct thread *td)
  328 {
  329         char *dirbuf, *cpos;
  330         int error, eofflag, dirbuflen, len, found;
  331         off_t off;
  332         struct dirent *dp;
  333         struct vattr va;
  334 
  335         KASSERT(VOP_ISLOCKED(vp), ("vp %p is not locked", vp));
  336         KASSERT(vp->v_type == VDIR, ("vp %p is not a directory", vp));
  337 
  338         found = 0;
  339 
  340         error = VOP_GETATTR(vp, &va, td->td_ucred);
  341         if (error)
  342                 return (found);
  343 
  344         dirbuflen = DEV_BSIZE;
  345         if (dirbuflen < va.va_blocksize)
  346                 dirbuflen = va.va_blocksize;
  347         dirbuf = (char *)malloc(dirbuflen, M_TEMP, M_WAITOK);
  348 
  349         off = 0;
  350         len = 0;
  351         do {
  352                 error = get_next_dirent(vp, &dp, dirbuf, dirbuflen, &off,
  353                                         &cpos, &len, &eofflag, td);
  354                 if (error)
  355                         goto out;
  356 
  357                 if (dp->d_type != DT_WHT && dp->d_fileno != 0 &&
  358                     strcmp(dp->d_name, dirname) == 0) {
  359                         found = 1;
  360                         goto out;
  361                 }
  362         } while (len > 0 || !eofflag);
  363 
  364 out:
  365         free(dirbuf, M_TEMP);
  366         return (found);
  367 }
  368 
  369 int
  370 vop_stdaccess(struct vop_access_args *ap)
  371 {
  372 
  373         KASSERT((ap->a_accmode & ~(VEXEC | VWRITE | VREAD | VADMIN |
  374             VAPPEND)) == 0, ("invalid bit in accmode"));
  375 
  376         return (VOP_ACCESSX(ap->a_vp, ap->a_accmode, ap->a_cred, ap->a_td));
  377 }
  378 
  379 int
  380 vop_stdaccessx(struct vop_accessx_args *ap)
  381 {
  382         int error;
  383         accmode_t accmode = ap->a_accmode;
  384 
  385         error = vfs_unixify_accmode(&accmode);
  386         if (error != 0)
  387                 return (error);
  388 
  389         if (accmode == 0)
  390                 return (0);
  391 
  392         return (VOP_ACCESS(ap->a_vp, accmode, ap->a_cred, ap->a_td));
  393 }
  394 
  395 /*
  396  * Advisory record locking support
  397  */
  398 int
  399 vop_stdadvlock(struct vop_advlock_args *ap)
  400 {
  401         struct vnode *vp;
  402         struct vattr vattr;
  403         int error;
  404 
  405         vp = ap->a_vp;
  406         if (ap->a_fl->l_whence == SEEK_END) {
  407                 /*
  408                  * The NFSv4 server must avoid doing a vn_lock() here, since it
  409                  * can deadlock the nfsd threads, due to a LOR.  Fortunately
  410                  * the NFSv4 server always uses SEEK_SET and this code is
  411                  * only required for the SEEK_END case.
  412                  */
  413                 vn_lock(vp, LK_SHARED | LK_RETRY);
  414                 error = VOP_GETATTR(vp, &vattr, curthread->td_ucred);
  415                 VOP_UNLOCK(vp, 0);
  416                 if (error)
  417                         return (error);
  418         } else
  419                 vattr.va_size = 0;
  420 
  421         return (lf_advlock(ap, &(vp->v_lockf), vattr.va_size));
  422 }
  423 
  424 int
  425 vop_stdadvlockasync(struct vop_advlockasync_args *ap)
  426 {
  427         struct vnode *vp;
  428         struct vattr vattr;
  429         int error;
  430 
  431         vp = ap->a_vp;
  432         if (ap->a_fl->l_whence == SEEK_END) {
  433                 /* The size argument is only needed for SEEK_END. */
  434                 vn_lock(vp, LK_SHARED | LK_RETRY);
  435                 error = VOP_GETATTR(vp, &vattr, curthread->td_ucred);
  436                 VOP_UNLOCK(vp, 0);
  437                 if (error)
  438                         return (error);
  439         } else
  440                 vattr.va_size = 0;
  441 
  442         return (lf_advlockasync(ap, &(vp->v_lockf), vattr.va_size));
  443 }
  444 
  445 int
  446 vop_stdadvlockpurge(struct vop_advlockpurge_args *ap)
  447 {
  448         struct vnode *vp;
  449 
  450         vp = ap->a_vp;
  451         lf_purgelocks(vp, &vp->v_lockf);
  452         return (0);
  453 }
  454 
  455 /*
  456  * vop_stdpathconf:
  457  *
  458  * Standard implementation of POSIX pathconf, to get information about limits
  459  * for a filesystem.
  460  * Override per filesystem for the case where the filesystem has smaller
  461  * limits.
  462  */
  463 int
  464 vop_stdpathconf(ap)
  465         struct vop_pathconf_args /* {
  466         struct vnode *a_vp;
  467         int a_name;
  468         int *a_retval;
  469         } */ *ap;
  470 {
  471 
  472         switch (ap->a_name) {
  473                 case _PC_NAME_MAX:
  474                         *ap->a_retval = NAME_MAX;
  475                         return (0);
  476                 case _PC_PATH_MAX:
  477                         *ap->a_retval = PATH_MAX;
  478                         return (0);
  479                 case _PC_LINK_MAX:
  480                         *ap->a_retval = LINK_MAX;
  481                         return (0);
  482                 case _PC_MAX_CANON:
  483                         *ap->a_retval = MAX_CANON;
  484                         return (0);
  485                 case _PC_MAX_INPUT:
  486                         *ap->a_retval = MAX_INPUT;
  487                         return (0);
  488                 case _PC_PIPE_BUF:
  489                         *ap->a_retval = PIPE_BUF;
  490                         return (0);
  491                 case _PC_CHOWN_RESTRICTED:
  492                         *ap->a_retval = 1;
  493                         return (0);
  494                 case _PC_VDISABLE:
  495                         *ap->a_retval = _POSIX_VDISABLE;
  496                         return (0);
  497                 default:
  498                         return (EINVAL);
  499         }
  500         /* NOTREACHED */
  501 }
  502 
  503 /*
  504  * Standard lock, unlock and islocked functions.
  505  */
  506 int
  507 vop_stdlock(ap)
  508         struct vop_lock1_args /* {
  509                 struct vnode *a_vp;
  510                 int a_flags;
  511                 char *file;
  512                 int line;
  513         } */ *ap;
  514 {
  515         struct vnode *vp = ap->a_vp;
  516 
  517         return (_lockmgr_args(vp->v_vnlock, ap->a_flags, VI_MTX(vp),
  518             LK_WMESG_DEFAULT, LK_PRIO_DEFAULT, LK_TIMO_DEFAULT, ap->a_file,
  519             ap->a_line));
  520 }
  521 
  522 /* See above. */
  523 int
  524 vop_stdunlock(ap)
  525         struct vop_unlock_args /* {
  526                 struct vnode *a_vp;
  527                 int a_flags;
  528         } */ *ap;
  529 {
  530         struct vnode *vp = ap->a_vp;
  531 
  532         return (lockmgr(vp->v_vnlock, ap->a_flags | LK_RELEASE, VI_MTX(vp)));
  533 }
  534 
  535 /* See above. */
  536 int
  537 vop_stdislocked(ap)
  538         struct vop_islocked_args /* {
  539                 struct vnode *a_vp;
  540         } */ *ap;
  541 {
  542 
  543         return (lockstatus(ap->a_vp->v_vnlock));
  544 }
  545 
  546 /*
  547  * Return true for select/poll.
  548  */
  549 int
  550 vop_nopoll(ap)
  551         struct vop_poll_args /* {
  552                 struct vnode *a_vp;
  553                 int  a_events;
  554                 struct ucred *a_cred;
  555                 struct thread *a_td;
  556         } */ *ap;
  557 {
  558 
  559         return (poll_no_poll(ap->a_events));
  560 }
  561 
  562 /*
  563  * Implement poll for local filesystems that support it.
  564  */
  565 int
  566 vop_stdpoll(ap)
  567         struct vop_poll_args /* {
  568                 struct vnode *a_vp;
  569                 int  a_events;
  570                 struct ucred *a_cred;
  571                 struct thread *a_td;
  572         } */ *ap;
  573 {
  574         if (ap->a_events & ~POLLSTANDARD)
  575                 return (vn_pollrecord(ap->a_vp, ap->a_td, ap->a_events));
  576         return (ap->a_events & (POLLIN | POLLOUT | POLLRDNORM | POLLWRNORM));
  577 }
  578 
  579 /*
  580  * Return our mount point, as we will take charge of the writes.
  581  */
  582 int
  583 vop_stdgetwritemount(ap)
  584         struct vop_getwritemount_args /* {
  585                 struct vnode *a_vp;
  586                 struct mount **a_mpp;
  587         } */ *ap;
  588 {
  589         struct mount *mp;
  590 
  591         /*
  592          * XXX Since this is called unlocked we may be recycled while
  593          * attempting to ref the mount.  If this is the case or mountpoint
  594          * will be set to NULL.  We only have to prevent this call from
  595          * returning with a ref to an incorrect mountpoint.  It is not
  596          * harmful to return with a ref to our previous mountpoint.
  597          */
  598         mp = ap->a_vp->v_mount;
  599         if (mp != NULL) {
  600                 vfs_ref(mp);
  601                 if (mp != ap->a_vp->v_mount) {
  602                         vfs_rel(mp);
  603                         mp = NULL;
  604                 }
  605         }
  606         *(ap->a_mpp) = mp;
  607         return (0);
  608 }
  609 
  610 /* XXX Needs good comment and VOP_BMAP(9) manpage */
  611 int
  612 vop_stdbmap(ap)
  613         struct vop_bmap_args /* {
  614                 struct vnode *a_vp;
  615                 daddr_t  a_bn;
  616                 struct bufobj **a_bop;
  617                 daddr_t *a_bnp;
  618                 int *a_runp;
  619                 int *a_runb;
  620         } */ *ap;
  621 {
  622 
  623         if (ap->a_bop != NULL)
  624                 *ap->a_bop = &ap->a_vp->v_bufobj;
  625         if (ap->a_bnp != NULL)
  626                 *ap->a_bnp = ap->a_bn * btodb(ap->a_vp->v_mount->mnt_stat.f_iosize);
  627         if (ap->a_runp != NULL)
  628                 *ap->a_runp = 0;
  629         if (ap->a_runb != NULL)
  630                 *ap->a_runb = 0;
  631         return (0);
  632 }
  633 
  634 int
  635 vop_stdfsync(ap)
  636         struct vop_fsync_args /* {
  637                 struct vnode *a_vp;
  638                 int a_waitfor;
  639                 struct thread *a_td;
  640         } */ *ap;
  641 {
  642         struct vnode *vp;
  643         struct buf *bp, *nbp;
  644         struct bufobj *bo;
  645         struct mount *mp;
  646         int error, maxretry;
  647 
  648         error = 0;
  649         maxretry = 10000;     /* large, arbitrarily chosen */
  650         vp = ap->a_vp;
  651         mp = NULL;
  652         if (vp->v_type == VCHR) {
  653                 VI_LOCK(vp);
  654                 mp = vp->v_rdev->si_mountpt;
  655                 VI_UNLOCK(vp);
  656         }
  657         bo = &vp->v_bufobj;
  658         BO_LOCK(bo);
  659 loop1:
  660         /*
  661          * MARK/SCAN initialization to avoid infinite loops.
  662          */
  663         TAILQ_FOREACH(bp, &bo->bo_dirty.bv_hd, b_bobufs) {
  664                 bp->b_vflags &= ~BV_SCANNED;
  665                 bp->b_error = 0;
  666         }
  667 
  668         /*
  669          * Flush all dirty buffers associated with a vnode.
  670          */
  671 loop2:
  672         TAILQ_FOREACH_SAFE(bp, &bo->bo_dirty.bv_hd, b_bobufs, nbp) {
  673                 if ((bp->b_vflags & BV_SCANNED) != 0)
  674                         continue;
  675                 bp->b_vflags |= BV_SCANNED;
  676                 if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT, NULL)) {
  677                         if (ap->a_waitfor != MNT_WAIT)
  678                                 continue;
  679                         if (BUF_LOCK(bp,
  680                             LK_EXCLUSIVE | LK_INTERLOCK | LK_SLEEPFAIL,
  681                             BO_LOCKPTR(bo)) != 0) {
  682                                 BO_LOCK(bo);
  683                                 goto loop1;
  684                         }
  685                         BO_LOCK(bo);
  686                 }
  687                 BO_UNLOCK(bo);
  688                 KASSERT(bp->b_bufobj == bo,
  689                     ("bp %p wrong b_bufobj %p should be %p",
  690                     bp, bp->b_bufobj, bo));
  691                 if ((bp->b_flags & B_DELWRI) == 0)
  692                         panic("fsync: not dirty");
  693                 if ((vp->v_object != NULL) && (bp->b_flags & B_CLUSTEROK)) {
  694                         vfs_bio_awrite(bp);
  695                 } else {
  696                         bremfree(bp);
  697                         bawrite(bp);
  698                 }
  699                 if (maxretry < 1000)
  700                         pause("dirty", hz < 1000 ? 1 : hz / 1000);
  701                 BO_LOCK(bo);
  702                 goto loop2;
  703         }
  704 
  705         /*
  706          * If synchronous the caller expects us to completely resolve all
  707          * dirty buffers in the system.  Wait for in-progress I/O to
  708          * complete (which could include background bitmap writes), then
  709          * retry if dirty blocks still exist.
  710          */
  711         if (ap->a_waitfor == MNT_WAIT) {
  712                 bufobj_wwait(bo, 0, 0);
  713                 if (bo->bo_dirty.bv_cnt > 0) {
  714                         /*
  715                          * If we are unable to write any of these buffers
  716                          * then we fail now rather than trying endlessly
  717                          * to write them out.
  718                          */
  719                         TAILQ_FOREACH(bp, &bo->bo_dirty.bv_hd, b_bobufs)
  720                                 if ((error = bp->b_error) == 0)
  721                                         continue;
  722                         if ((mp != NULL && mp->mnt_secondary_writes > 0) ||
  723                             (error == 0 && --maxretry >= 0))
  724                                 goto loop1;
  725                         if (error == 0)
  726                                 error = EAGAIN;
  727                 }
  728         }
  729         BO_UNLOCK(bo);
  730         if (error != 0)
  731                 vn_printf(vp, "fsync: giving up on dirty (error = %d) ", error);
  732 
  733         return (error);
  734 }
  735 
  736 /* XXX Needs good comment and more info in the manpage (VOP_GETPAGES(9)). */
  737 int
  738 vop_stdgetpages(ap)
  739         struct vop_getpages_args /* {
  740                 struct vnode *a_vp;
  741                 vm_page_t *a_m;
  742                 int a_count;
  743                 int a_reqpage;
  744                 vm_ooffset_t a_offset;
  745         } */ *ap;
  746 {
  747 
  748         return vnode_pager_generic_getpages(ap->a_vp, ap->a_m,
  749             ap->a_count, ap->a_reqpage);
  750 }
  751 
  752 int
  753 vop_stdkqfilter(struct vop_kqfilter_args *ap)
  754 {
  755         return vfs_kqfilter(ap);
  756 }
  757 
  758 /* XXX Needs good comment and more info in the manpage (VOP_PUTPAGES(9)). */
  759 int
  760 vop_stdputpages(ap)
  761         struct vop_putpages_args /* {
  762                 struct vnode *a_vp;
  763                 vm_page_t *a_m;
  764                 int a_count;
  765                 int a_sync;
  766                 int *a_rtvals;
  767                 vm_ooffset_t a_offset;
  768         } */ *ap;
  769 {
  770 
  771         return vnode_pager_generic_putpages(ap->a_vp, ap->a_m, ap->a_count,
  772              ap->a_sync, ap->a_rtvals);
  773 }
  774 
  775 int
  776 vop_stdvptofh(struct vop_vptofh_args *ap)
  777 {
  778         return (EOPNOTSUPP);
  779 }
  780 
  781 int
  782 vop_stdvptocnp(struct vop_vptocnp_args *ap)
  783 {
  784         struct vnode *vp = ap->a_vp;
  785         struct vnode **dvp = ap->a_vpp;
  786         struct ucred *cred = ap->a_cred;
  787         char *buf = ap->a_buf;
  788         int *buflen = ap->a_buflen;
  789         char *dirbuf, *cpos;
  790         int i, error, eofflag, dirbuflen, flags, locked, len, covered;
  791         off_t off;
  792         ino_t fileno;
  793         struct vattr va;
  794         struct nameidata nd;
  795         struct thread *td;
  796         struct dirent *dp;
  797         struct vnode *mvp;
  798 
  799         i = *buflen;
  800         error = 0;
  801         covered = 0;
  802         td = curthread;
  803 
  804         if (vp->v_type != VDIR)
  805                 return (ENOENT);
  806 
  807         error = VOP_GETATTR(vp, &va, cred);
  808         if (error)
  809                 return (error);
  810 
  811         VREF(vp);
  812         locked = VOP_ISLOCKED(vp);
  813         VOP_UNLOCK(vp, 0);
  814         NDINIT_ATVP(&nd, LOOKUP, FOLLOW | LOCKLEAF, UIO_SYSSPACE,
  815             "..", vp, td);
  816         flags = FREAD;
  817         error = vn_open_cred(&nd, &flags, 0, VN_OPEN_NOAUDIT, cred, NULL);
  818         if (error) {
  819                 vn_lock(vp, locked | LK_RETRY);
  820                 return (error);
  821         }
  822         NDFREE(&nd, NDF_ONLY_PNBUF);
  823 
  824         mvp = *dvp = nd.ni_vp;
  825 
  826         if (vp->v_mount != (*dvp)->v_mount &&
  827             ((*dvp)->v_vflag & VV_ROOT) &&
  828             ((*dvp)->v_mount->mnt_flag & MNT_UNION)) {
  829                 *dvp = (*dvp)->v_mount->mnt_vnodecovered;
  830                 VREF(mvp);
  831                 VOP_UNLOCK(mvp, 0);
  832                 vn_close(mvp, FREAD, cred, td);
  833                 VREF(*dvp);
  834                 vn_lock(*dvp, LK_EXCLUSIVE | LK_RETRY);
  835                 covered = 1;
  836         }
  837 
  838         fileno = va.va_fileid;
  839 
  840         dirbuflen = DEV_BSIZE;
  841         if (dirbuflen < va.va_blocksize)
  842                 dirbuflen = va.va_blocksize;
  843         dirbuf = (char *)malloc(dirbuflen, M_TEMP, M_WAITOK);
  844 
  845         if ((*dvp)->v_type != VDIR) {
  846                 error = ENOENT;
  847                 goto out;
  848         }
  849 
  850         off = 0;
  851         len = 0;
  852         do {
  853                 /* call VOP_READDIR of parent */
  854                 error = get_next_dirent(*dvp, &dp, dirbuf, dirbuflen, &off,
  855                                         &cpos, &len, &eofflag, td);
  856                 if (error)
  857                         goto out;
  858 
  859                 if ((dp->d_type != DT_WHT) &&
  860                     (dp->d_fileno == fileno)) {
  861                         if (covered) {
  862                                 VOP_UNLOCK(*dvp, 0);
  863                                 vn_lock(mvp, LK_EXCLUSIVE | LK_RETRY);
  864                                 if (dirent_exists(mvp, dp->d_name, td)) {
  865                                         error = ENOENT;
  866                                         VOP_UNLOCK(mvp, 0);
  867                                         vn_lock(*dvp, LK_EXCLUSIVE | LK_RETRY);
  868                                         goto out;
  869                                 }
  870                                 VOP_UNLOCK(mvp, 0);
  871                                 vn_lock(*dvp, LK_EXCLUSIVE | LK_RETRY);
  872                         }
  873                         i -= dp->d_namlen;
  874 
  875                         if (i < 0) {
  876                                 error = ENOMEM;
  877                                 goto out;
  878                         }
  879                         if (dp->d_namlen == 1 && dp->d_name[0] == '.') {
  880                                 error = ENOENT;
  881                         } else {
  882                                 bcopy(dp->d_name, buf + i, dp->d_namlen);
  883                                 error = 0;
  884                         }
  885                         goto out;
  886                 }
  887         } while (len > 0 || !eofflag);
  888         error = ENOENT;
  889 
  890 out:
  891         free(dirbuf, M_TEMP);
  892         if (!error) {
  893                 *buflen = i;
  894                 vref(*dvp);
  895         }
  896         if (covered) {
  897                 vput(*dvp);
  898                 vrele(mvp);
  899         } else {
  900                 VOP_UNLOCK(mvp, 0);
  901                 vn_close(mvp, FREAD, cred, td);
  902         }
  903         vn_lock(vp, locked | LK_RETRY);
  904         return (error);
  905 }
  906 
  907 int
  908 vop_stdallocate(struct vop_allocate_args *ap)
  909 {
  910 #ifdef __notyet__
  911         struct statfs sfs;
  912 #endif
  913         struct iovec aiov;
  914         struct vattr vattr, *vap;
  915         struct uio auio;
  916         off_t fsize, len, cur, offset;
  917         uint8_t *buf;
  918         struct thread *td;
  919         struct vnode *vp;
  920         size_t iosize;
  921         int error;
  922 
  923         buf = NULL;
  924         error = 0;
  925         td = curthread;
  926         vap = &vattr;
  927         vp = ap->a_vp;
  928         len = *ap->a_len;
  929         offset = *ap->a_offset;
  930 
  931         error = VOP_GETATTR(vp, vap, td->td_ucred);
  932         if (error != 0)
  933                 goto out;
  934         fsize = vap->va_size;
  935         iosize = vap->va_blocksize;
  936         if (iosize == 0)
  937                 iosize = BLKDEV_IOSIZE;
  938         if (iosize > MAXPHYS)
  939                 iosize = MAXPHYS;
  940         buf = malloc(iosize, M_TEMP, M_WAITOK);
  941 
  942 #ifdef __notyet__
  943         /*
  944          * Check if the filesystem sets f_maxfilesize; if not use
  945          * VOP_SETATTR to perform the check.
  946          */
  947         error = VFS_STATFS(vp->v_mount, &sfs, td);
  948         if (error != 0)
  949                 goto out;
  950         if (sfs.f_maxfilesize) {
  951                 if (offset > sfs.f_maxfilesize || len > sfs.f_maxfilesize ||
  952                     offset + len > sfs.f_maxfilesize) {
  953                         error = EFBIG;
  954                         goto out;
  955                 }
  956         } else
  957 #endif
  958         if (offset + len > vap->va_size) {
  959                 /*
  960                  * Test offset + len against the filesystem's maxfilesize.
  961                  */
  962                 VATTR_NULL(vap);
  963                 vap->va_size = offset + len;
  964                 error = VOP_SETATTR(vp, vap, td->td_ucred);
  965                 if (error != 0)
  966                         goto out;
  967                 VATTR_NULL(vap);
  968                 vap->va_size = fsize;
  969                 error = VOP_SETATTR(vp, vap, td->td_ucred);
  970                 if (error != 0)
  971                         goto out;
  972         }
  973 
  974         for (;;) {
  975                 /*
  976                  * Read and write back anything below the nominal file
  977                  * size.  There's currently no way outside the filesystem
  978                  * to know whether this area is sparse or not.
  979                  */
  980                 cur = iosize;
  981                 if ((offset % iosize) != 0)
  982                         cur -= (offset % iosize);
  983                 if (cur > len)
  984                         cur = len;
  985                 if (offset < fsize) {
  986                         aiov.iov_base = buf;
  987                         aiov.iov_len = cur;
  988                         auio.uio_iov = &aiov;
  989                         auio.uio_iovcnt = 1;
  990                         auio.uio_offset = offset;
  991                         auio.uio_resid = cur;
  992                         auio.uio_segflg = UIO_SYSSPACE;
  993                         auio.uio_rw = UIO_READ;
  994                         auio.uio_td = td;
  995                         error = VOP_READ(vp, &auio, 0, td->td_ucred);
  996                         if (error != 0)
  997                                 break;
  998                         if (auio.uio_resid > 0) {
  999                                 bzero(buf + cur - auio.uio_resid,
 1000                                     auio.uio_resid);
 1001                         }
 1002                 } else {
 1003                         bzero(buf, cur);
 1004                 }
 1005 
 1006                 aiov.iov_base = buf;
 1007                 aiov.iov_len = cur;
 1008                 auio.uio_iov = &aiov;
 1009                 auio.uio_iovcnt = 1;
 1010                 auio.uio_offset = offset;
 1011                 auio.uio_resid = cur;
 1012                 auio.uio_segflg = UIO_SYSSPACE;
 1013                 auio.uio_rw = UIO_WRITE;
 1014                 auio.uio_td = td;
 1015 
 1016                 error = VOP_WRITE(vp, &auio, 0, td->td_ucred);
 1017                 if (error != 0)
 1018                         break;
 1019 
 1020                 len -= cur;
 1021                 offset += cur;
 1022                 if (len == 0)
 1023                         break;
 1024                 if (should_yield())
 1025                         break;
 1026         }
 1027 
 1028  out:
 1029         *ap->a_len = len;
 1030         *ap->a_offset = offset;
 1031         free(buf, M_TEMP);
 1032         return (error);
 1033 }
 1034 
 1035 int
 1036 vop_stdadvise(struct vop_advise_args *ap)
 1037 {
 1038         struct vnode *vp;
 1039         off_t start, end;
 1040         int error;
 1041 
 1042         vp = ap->a_vp;
 1043         switch (ap->a_advice) {
 1044         case POSIX_FADV_WILLNEED:
 1045                 /*
 1046                  * Do nothing for now.  Filesystems should provide a
 1047                  * custom method which starts an asynchronous read of
 1048                  * the requested region.
 1049                  */
 1050                 error = 0;
 1051                 break;
 1052         case POSIX_FADV_DONTNEED:
 1053                 /*
 1054                  * Flush any open FS buffers and then remove pages
 1055                  * from the backing VM object.  Using vinvalbuf() here
 1056                  * is a bit heavy-handed as it flushes all buffers for
 1057                  * the given vnode, not just the buffers covering the
 1058                  * requested range.
 1059                  */
 1060                 error = 0;
 1061                 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
 1062                 if (vp->v_iflag & VI_DOOMED) {
 1063                         VOP_UNLOCK(vp, 0);
 1064                         break;
 1065                 }
 1066                 vinvalbuf(vp, V_CLEANONLY, 0, 0);
 1067                 if (vp->v_object != NULL) {
 1068                         start = trunc_page(ap->a_start);
 1069                         end = round_page(ap->a_end);
 1070                         VM_OBJECT_WLOCK(vp->v_object);
 1071                         vm_object_page_cache(vp->v_object, OFF_TO_IDX(start),
 1072                             OFF_TO_IDX(end));
 1073                         VM_OBJECT_WUNLOCK(vp->v_object);
 1074                 }
 1075                 VOP_UNLOCK(vp, 0);
 1076                 break;
 1077         default:
 1078                 error = EINVAL;
 1079                 break;
 1080         }
 1081         return (error);
 1082 }
 1083 
 1084 int
 1085 vop_stdunp_bind(struct vop_unp_bind_args *ap)
 1086 {
 1087 
 1088         ap->a_vp->v_socket = ap->a_socket;
 1089         return (0);
 1090 }
 1091 
 1092 int
 1093 vop_stdunp_connect(struct vop_unp_connect_args *ap)
 1094 {
 1095 
 1096         *ap->a_socket = ap->a_vp->v_socket;
 1097         return (0);
 1098 }
 1099 
 1100 int
 1101 vop_stdunp_detach(struct vop_unp_detach_args *ap)
 1102 {
 1103 
 1104         ap->a_vp->v_socket = NULL;
 1105         return (0);
 1106 }
 1107 
 1108 static int
 1109 vop_stdis_text(struct vop_is_text_args *ap)
 1110 {
 1111 
 1112         return ((ap->a_vp->v_vflag & VV_TEXT) != 0);
 1113 }
 1114 
 1115 static int
 1116 vop_stdset_text(struct vop_set_text_args *ap)
 1117 {
 1118 
 1119         ap->a_vp->v_vflag |= VV_TEXT;
 1120         return (0);
 1121 }
 1122 
 1123 static int
 1124 vop_stdunset_text(struct vop_unset_text_args *ap)
 1125 {
 1126 
 1127         ap->a_vp->v_vflag &= ~VV_TEXT;
 1128         return (0);
 1129 }
 1130 
 1131 static int
 1132 vop_stdget_writecount(struct vop_get_writecount_args *ap)
 1133 {
 1134 
 1135         *ap->a_writecount = ap->a_vp->v_writecount;
 1136         return (0);
 1137 }
 1138 
 1139 static int
 1140 vop_stdadd_writecount(struct vop_add_writecount_args *ap)
 1141 {
 1142 
 1143         ap->a_vp->v_writecount += ap->a_inc;
 1144         return (0);
 1145 }
 1146 
 1147 /*
 1148  * vfs default ops
 1149  * used to fill the vfs function table to get reasonable default return values.
 1150  */
 1151 int
 1152 vfs_stdroot (mp, flags, vpp)
 1153         struct mount *mp;
 1154         int flags;
 1155         struct vnode **vpp;
 1156 {
 1157 
 1158         return (EOPNOTSUPP);
 1159 }
 1160 
 1161 int
 1162 vfs_stdstatfs (mp, sbp)
 1163         struct mount *mp;
 1164         struct statfs *sbp;
 1165 {
 1166 
 1167         return (EOPNOTSUPP);
 1168 }
 1169 
 1170 int
 1171 vfs_stdquotactl (mp, cmds, uid, arg)
 1172         struct mount *mp;
 1173         int cmds;
 1174         uid_t uid;
 1175         void *arg;
 1176 {
 1177 
 1178         return (EOPNOTSUPP);
 1179 }
 1180 
 1181 int
 1182 vfs_stdsync(mp, waitfor)
 1183         struct mount *mp;
 1184         int waitfor;
 1185 {
 1186         struct vnode *vp, *mvp;
 1187         struct thread *td;
 1188         int error, lockreq, allerror = 0;
 1189 
 1190         td = curthread;
 1191         lockreq = LK_EXCLUSIVE | LK_INTERLOCK;
 1192         if (waitfor != MNT_WAIT)
 1193                 lockreq |= LK_NOWAIT;
 1194         /*
 1195          * Force stale buffer cache information to be flushed.
 1196          */
 1197 loop:
 1198         MNT_VNODE_FOREACH_ALL(vp, mp, mvp) {
 1199                 if (vp->v_bufobj.bo_dirty.bv_cnt == 0) {
 1200                         VI_UNLOCK(vp);
 1201                         continue;
 1202                 }
 1203                 if ((error = vget(vp, lockreq, td)) != 0) {
 1204                         if (error == ENOENT) {
 1205                                 MNT_VNODE_FOREACH_ALL_ABORT(mp, mvp);
 1206                                 goto loop;
 1207                         }
 1208                         continue;
 1209                 }
 1210                 error = VOP_FSYNC(vp, waitfor, td);
 1211                 if (error)
 1212                         allerror = error;
 1213                 vput(vp);
 1214         }
 1215         return (allerror);
 1216 }
 1217 
 1218 int
 1219 vfs_stdnosync (mp, waitfor)
 1220         struct mount *mp;
 1221         int waitfor;
 1222 {
 1223 
 1224         return (0);
 1225 }
 1226 
 1227 int
 1228 vfs_stdvget (mp, ino, flags, vpp)
 1229         struct mount *mp;
 1230         ino_t ino;
 1231         int flags;
 1232         struct vnode **vpp;
 1233 {
 1234 
 1235         return (EOPNOTSUPP);
 1236 }
 1237 
 1238 int
 1239 vfs_stdfhtovp (mp, fhp, flags, vpp)
 1240         struct mount *mp;
 1241         struct fid *fhp;
 1242         int flags;
 1243         struct vnode **vpp;
 1244 {
 1245 
 1246         return (EOPNOTSUPP);
 1247 }
 1248 
 1249 int
 1250 vfs_stdinit (vfsp)
 1251         struct vfsconf *vfsp;
 1252 {
 1253 
 1254         return (0);
 1255 }
 1256 
 1257 int
 1258 vfs_stduninit (vfsp)
 1259         struct vfsconf *vfsp;
 1260 {
 1261 
 1262         return(0);
 1263 }
 1264 
 1265 int
 1266 vfs_stdextattrctl(mp, cmd, filename_vp, attrnamespace, attrname)
 1267         struct mount *mp;
 1268         int cmd;
 1269         struct vnode *filename_vp;
 1270         int attrnamespace;
 1271         const char *attrname;
 1272 {
 1273 
 1274         if (filename_vp != NULL)
 1275                 VOP_UNLOCK(filename_vp, 0);
 1276         return (EOPNOTSUPP);
 1277 }
 1278 
 1279 int
 1280 vfs_stdsysctl(mp, op, req)
 1281         struct mount *mp;
 1282         fsctlop_t op;
 1283         struct sysctl_req *req;
 1284 {
 1285 
 1286         return (EOPNOTSUPP);
 1287 }
 1288 
 1289 /* end of vfs default ops */

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