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: releng/11.0/sys/kern/vfs_default.c 296572 2016-03-09 19:05:11Z jhb $");
   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 static int vop_stdgetpages_async(struct vop_getpages_async_args *ap);
   87 
   88 /*
   89  * This vnode table stores what we want to do if the filesystem doesn't
   90  * implement a particular VOP.
   91  *
   92  * If there is no specific entry here, we will return EOPNOTSUPP.
   93  *
   94  * Note that every filesystem has to implement either vop_access
   95  * or vop_accessx; failing to do so will result in immediate crash
   96  * due to stack overflow, as vop_stdaccess() calls vop_stdaccessx(),
   97  * which calls vop_stdaccess() etc.
   98  */
   99 
  100 struct vop_vector default_vnodeops = {
  101         .vop_default =          NULL,
  102         .vop_bypass =           VOP_EOPNOTSUPP,
  103 
  104         .vop_access =           vop_stdaccess,
  105         .vop_accessx =          vop_stdaccessx,
  106         .vop_advise =           vop_stdadvise,
  107         .vop_advlock =          vop_stdadvlock,
  108         .vop_advlockasync =     vop_stdadvlockasync,
  109         .vop_advlockpurge =     vop_stdadvlockpurge,
  110         .vop_allocate =         vop_stdallocate,
  111         .vop_bmap =             vop_stdbmap,
  112         .vop_close =            VOP_NULL,
  113         .vop_fsync =            VOP_NULL,
  114         .vop_getpages =         vop_stdgetpages,
  115         .vop_getpages_async =   vop_stdgetpages_async,
  116         .vop_getwritemount =    vop_stdgetwritemount,
  117         .vop_inactive =         VOP_NULL,
  118         .vop_ioctl =            VOP_ENOTTY,
  119         .vop_kqfilter =         vop_stdkqfilter,
  120         .vop_islocked =         vop_stdislocked,
  121         .vop_lock1 =            vop_stdlock,
  122         .vop_lookup =           vop_nolookup,
  123         .vop_open =             VOP_NULL,
  124         .vop_pathconf =         VOP_EINVAL,
  125         .vop_poll =             vop_nopoll,
  126         .vop_putpages =         vop_stdputpages,
  127         .vop_readlink =         VOP_EINVAL,
  128         .vop_rename =           vop_norename,
  129         .vop_revoke =           VOP_PANIC,
  130         .vop_strategy =         vop_nostrategy,
  131         .vop_unlock =           vop_stdunlock,
  132         .vop_vptocnp =          vop_stdvptocnp,
  133         .vop_vptofh =           vop_stdvptofh,
  134         .vop_unp_bind =         vop_stdunp_bind,
  135         .vop_unp_connect =      vop_stdunp_connect,
  136         .vop_unp_detach =       vop_stdunp_detach,
  137         .vop_is_text =          vop_stdis_text,
  138         .vop_set_text =         vop_stdset_text,
  139         .vop_unset_text =       vop_stdunset_text,
  140         .vop_get_writecount =   vop_stdget_writecount,
  141         .vop_add_writecount =   vop_stdadd_writecount,
  142 };
  143 
  144 /*
  145  * Series of placeholder functions for various error returns for
  146  * VOPs.
  147  */
  148 
  149 int
  150 vop_eopnotsupp(struct vop_generic_args *ap)
  151 {
  152         /*
  153         printf("vop_notsupp[%s]\n", ap->a_desc->vdesc_name);
  154         */
  155 
  156         return (EOPNOTSUPP);
  157 }
  158 
  159 int
  160 vop_ebadf(struct vop_generic_args *ap)
  161 {
  162 
  163         return (EBADF);
  164 }
  165 
  166 int
  167 vop_enotty(struct vop_generic_args *ap)
  168 {
  169 
  170         return (ENOTTY);
  171 }
  172 
  173 int
  174 vop_einval(struct vop_generic_args *ap)
  175 {
  176 
  177         return (EINVAL);
  178 }
  179 
  180 int
  181 vop_enoent(struct vop_generic_args *ap)
  182 {
  183 
  184         return (ENOENT);
  185 }
  186 
  187 int
  188 vop_null(struct vop_generic_args *ap)
  189 {
  190 
  191         return (0);
  192 }
  193 
  194 /*
  195  * Helper function to panic on some bad VOPs in some filesystems.
  196  */
  197 int
  198 vop_panic(struct vop_generic_args *ap)
  199 {
  200 
  201         panic("filesystem goof: vop_panic[%s]", ap->a_desc->vdesc_name);
  202 }
  203 
  204 /*
  205  * vop_std<something> and vop_no<something> are default functions for use by
  206  * filesystems that need the "default reasonable" implementation for a
  207  * particular operation.
  208  *
  209  * The documentation for the operations they implement exists (if it exists)
  210  * in the VOP_<SOMETHING>(9) manpage (all uppercase).
  211  */
  212 
  213 /*
  214  * Default vop for filesystems that do not support name lookup
  215  */
  216 static int
  217 vop_nolookup(ap)
  218         struct vop_lookup_args /* {
  219                 struct vnode *a_dvp;
  220                 struct vnode **a_vpp;
  221                 struct componentname *a_cnp;
  222         } */ *ap;
  223 {
  224 
  225         *ap->a_vpp = NULL;
  226         return (ENOTDIR);
  227 }
  228 
  229 /*
  230  * vop_norename:
  231  *
  232  * Handle unlock and reference counting for arguments of vop_rename
  233  * for filesystems that do not implement rename operation.
  234  */
  235 static int
  236 vop_norename(struct vop_rename_args *ap)
  237 {
  238 
  239         vop_rename_fail(ap);
  240         return (EOPNOTSUPP);
  241 }
  242 
  243 /*
  244  *      vop_nostrategy:
  245  *
  246  *      Strategy routine for VFS devices that have none.
  247  *
  248  *      BIO_ERROR and B_INVAL must be cleared prior to calling any strategy
  249  *      routine.  Typically this is done for a BIO_READ strategy call.
  250  *      Typically B_INVAL is assumed to already be clear prior to a write
  251  *      and should not be cleared manually unless you just made the buffer
  252  *      invalid.  BIO_ERROR should be cleared either way.
  253  */
  254 
  255 static int
  256 vop_nostrategy (struct vop_strategy_args *ap)
  257 {
  258         printf("No strategy for buffer at %p\n", ap->a_bp);
  259         vprint("vnode", ap->a_vp);
  260         ap->a_bp->b_ioflags |= BIO_ERROR;
  261         ap->a_bp->b_error = EOPNOTSUPP;
  262         bufdone(ap->a_bp);
  263         return (EOPNOTSUPP);
  264 }
  265 
  266 static int
  267 get_next_dirent(struct vnode *vp, struct dirent **dpp, char *dirbuf,
  268                 int dirbuflen, off_t *off, char **cpos, int *len,
  269                 int *eofflag, struct thread *td)
  270 {
  271         int error, reclen;
  272         struct uio uio;
  273         struct iovec iov;
  274         struct dirent *dp;
  275 
  276         KASSERT(VOP_ISLOCKED(vp), ("vp %p is not locked", vp));
  277         KASSERT(vp->v_type == VDIR, ("vp %p is not a directory", vp));
  278 
  279         if (*len == 0) {
  280                 iov.iov_base = dirbuf;
  281                 iov.iov_len = dirbuflen;
  282 
  283                 uio.uio_iov = &iov;
  284                 uio.uio_iovcnt = 1;
  285                 uio.uio_offset = *off;
  286                 uio.uio_resid = dirbuflen;
  287                 uio.uio_segflg = UIO_SYSSPACE;
  288                 uio.uio_rw = UIO_READ;
  289                 uio.uio_td = td;
  290 
  291                 *eofflag = 0;
  292 
  293 #ifdef MAC
  294                 error = mac_vnode_check_readdir(td->td_ucred, vp);
  295                 if (error == 0)
  296 #endif
  297                         error = VOP_READDIR(vp, &uio, td->td_ucred, eofflag,
  298                                 NULL, NULL);
  299                 if (error)
  300                         return (error);
  301 
  302                 *off = uio.uio_offset;
  303 
  304                 *cpos = dirbuf;
  305                 *len = (dirbuflen - uio.uio_resid);
  306 
  307                 if (*len == 0)
  308                         return (ENOENT);
  309         }
  310 
  311         dp = (struct dirent *)(*cpos);
  312         reclen = dp->d_reclen;
  313         *dpp = dp;
  314 
  315         /* check for malformed directory.. */
  316         if (reclen < DIRENT_MINSIZE)
  317                 return (EINVAL);
  318 
  319         *cpos += reclen;
  320         *len -= reclen;
  321 
  322         return (0);
  323 }
  324 
  325 /*
  326  * Check if a named file exists in a given directory vnode.
  327  */
  328 static int
  329 dirent_exists(struct vnode *vp, const char *dirname, struct thread *td)
  330 {
  331         char *dirbuf, *cpos;
  332         int error, eofflag, dirbuflen, len, found;
  333         off_t off;
  334         struct dirent *dp;
  335         struct vattr va;
  336 
  337         KASSERT(VOP_ISLOCKED(vp), ("vp %p is not locked", vp));
  338         KASSERT(vp->v_type == VDIR, ("vp %p is not a directory", vp));
  339 
  340         found = 0;
  341 
  342         error = VOP_GETATTR(vp, &va, td->td_ucred);
  343         if (error)
  344                 return (found);
  345 
  346         dirbuflen = DEV_BSIZE;
  347         if (dirbuflen < va.va_blocksize)
  348                 dirbuflen = va.va_blocksize;
  349         dirbuf = (char *)malloc(dirbuflen, M_TEMP, M_WAITOK);
  350 
  351         off = 0;
  352         len = 0;
  353         do {
  354                 error = get_next_dirent(vp, &dp, dirbuf, dirbuflen, &off,
  355                                         &cpos, &len, &eofflag, td);
  356                 if (error)
  357                         goto out;
  358 
  359                 if (dp->d_type != DT_WHT && dp->d_fileno != 0 &&
  360                     strcmp(dp->d_name, dirname) == 0) {
  361                         found = 1;
  362                         goto out;
  363                 }
  364         } while (len > 0 || !eofflag);
  365 
  366 out:
  367         free(dirbuf, M_TEMP);
  368         return (found);
  369 }
  370 
  371 int
  372 vop_stdaccess(struct vop_access_args *ap)
  373 {
  374 
  375         KASSERT((ap->a_accmode & ~(VEXEC | VWRITE | VREAD | VADMIN |
  376             VAPPEND)) == 0, ("invalid bit in accmode"));
  377 
  378         return (VOP_ACCESSX(ap->a_vp, ap->a_accmode, ap->a_cred, ap->a_td));
  379 }
  380 
  381 int
  382 vop_stdaccessx(struct vop_accessx_args *ap)
  383 {
  384         int error;
  385         accmode_t accmode = ap->a_accmode;
  386 
  387         error = vfs_unixify_accmode(&accmode);
  388         if (error != 0)
  389                 return (error);
  390 
  391         if (accmode == 0)
  392                 return (0);
  393 
  394         return (VOP_ACCESS(ap->a_vp, accmode, ap->a_cred, ap->a_td));
  395 }
  396 
  397 /*
  398  * Advisory record locking support
  399  */
  400 int
  401 vop_stdadvlock(struct vop_advlock_args *ap)
  402 {
  403         struct vnode *vp;
  404         struct vattr vattr;
  405         int error;
  406 
  407         vp = ap->a_vp;
  408         if (ap->a_fl->l_whence == SEEK_END) {
  409                 /*
  410                  * The NFSv4 server must avoid doing a vn_lock() here, since it
  411                  * can deadlock the nfsd threads, due to a LOR.  Fortunately
  412                  * the NFSv4 server always uses SEEK_SET and this code is
  413                  * only required for the SEEK_END case.
  414                  */
  415                 vn_lock(vp, LK_SHARED | LK_RETRY);
  416                 error = VOP_GETATTR(vp, &vattr, curthread->td_ucred);
  417                 VOP_UNLOCK(vp, 0);
  418                 if (error)
  419                         return (error);
  420         } else
  421                 vattr.va_size = 0;
  422 
  423         return (lf_advlock(ap, &(vp->v_lockf), vattr.va_size));
  424 }
  425 
  426 int
  427 vop_stdadvlockasync(struct vop_advlockasync_args *ap)
  428 {
  429         struct vnode *vp;
  430         struct vattr vattr;
  431         int error;
  432 
  433         vp = ap->a_vp;
  434         if (ap->a_fl->l_whence == SEEK_END) {
  435                 /* The size argument is only needed for SEEK_END. */
  436                 vn_lock(vp, LK_SHARED | LK_RETRY);
  437                 error = VOP_GETATTR(vp, &vattr, curthread->td_ucred);
  438                 VOP_UNLOCK(vp, 0);
  439                 if (error)
  440                         return (error);
  441         } else
  442                 vattr.va_size = 0;
  443 
  444         return (lf_advlockasync(ap, &(vp->v_lockf), vattr.va_size));
  445 }
  446 
  447 int
  448 vop_stdadvlockpurge(struct vop_advlockpurge_args *ap)
  449 {
  450         struct vnode *vp;
  451 
  452         vp = ap->a_vp;
  453         lf_purgelocks(vp, &vp->v_lockf);
  454         return (0);
  455 }
  456 
  457 /*
  458  * vop_stdpathconf:
  459  *
  460  * Standard implementation of POSIX pathconf, to get information about limits
  461  * for a filesystem.
  462  * Override per filesystem for the case where the filesystem has smaller
  463  * limits.
  464  */
  465 int
  466 vop_stdpathconf(ap)
  467         struct vop_pathconf_args /* {
  468         struct vnode *a_vp;
  469         int a_name;
  470         int *a_retval;
  471         } */ *ap;
  472 {
  473 
  474         switch (ap->a_name) {
  475                 case _PC_ASYNC_IO:
  476                         *ap->a_retval = _POSIX_ASYNCHRONOUS_IO;
  477                         return (0);
  478                 case _PC_NAME_MAX:
  479                         *ap->a_retval = NAME_MAX;
  480                         return (0);
  481                 case _PC_PATH_MAX:
  482                         *ap->a_retval = PATH_MAX;
  483                         return (0);
  484                 case _PC_LINK_MAX:
  485                         *ap->a_retval = LINK_MAX;
  486                         return (0);
  487                 case _PC_MAX_CANON:
  488                         *ap->a_retval = MAX_CANON;
  489                         return (0);
  490                 case _PC_MAX_INPUT:
  491                         *ap->a_retval = MAX_INPUT;
  492                         return (0);
  493                 case _PC_PIPE_BUF:
  494                         *ap->a_retval = PIPE_BUF;
  495                         return (0);
  496                 case _PC_CHOWN_RESTRICTED:
  497                         *ap->a_retval = 1;
  498                         return (0);
  499                 case _PC_VDISABLE:
  500                         *ap->a_retval = _POSIX_VDISABLE;
  501                         return (0);
  502                 default:
  503                         return (EINVAL);
  504         }
  505         /* NOTREACHED */
  506 }
  507 
  508 /*
  509  * Standard lock, unlock and islocked functions.
  510  */
  511 int
  512 vop_stdlock(ap)
  513         struct vop_lock1_args /* {
  514                 struct vnode *a_vp;
  515                 int a_flags;
  516                 char *file;
  517                 int line;
  518         } */ *ap;
  519 {
  520         struct vnode *vp = ap->a_vp;
  521 
  522         return (_lockmgr_args(vp->v_vnlock, ap->a_flags, VI_MTX(vp),
  523             LK_WMESG_DEFAULT, LK_PRIO_DEFAULT, LK_TIMO_DEFAULT, ap->a_file,
  524             ap->a_line));
  525 }
  526 
  527 /* See above. */
  528 int
  529 vop_stdunlock(ap)
  530         struct vop_unlock_args /* {
  531                 struct vnode *a_vp;
  532                 int a_flags;
  533         } */ *ap;
  534 {
  535         struct vnode *vp = ap->a_vp;
  536 
  537         return (lockmgr(vp->v_vnlock, ap->a_flags | LK_RELEASE, VI_MTX(vp)));
  538 }
  539 
  540 /* See above. */
  541 int
  542 vop_stdislocked(ap)
  543         struct vop_islocked_args /* {
  544                 struct vnode *a_vp;
  545         } */ *ap;
  546 {
  547 
  548         return (lockstatus(ap->a_vp->v_vnlock));
  549 }
  550 
  551 /*
  552  * Return true for select/poll.
  553  */
  554 int
  555 vop_nopoll(ap)
  556         struct vop_poll_args /* {
  557                 struct vnode *a_vp;
  558                 int  a_events;
  559                 struct ucred *a_cred;
  560                 struct thread *a_td;
  561         } */ *ap;
  562 {
  563 
  564         return (poll_no_poll(ap->a_events));
  565 }
  566 
  567 /*
  568  * Implement poll for local filesystems that support it.
  569  */
  570 int
  571 vop_stdpoll(ap)
  572         struct vop_poll_args /* {
  573                 struct vnode *a_vp;
  574                 int  a_events;
  575                 struct ucred *a_cred;
  576                 struct thread *a_td;
  577         } */ *ap;
  578 {
  579         if (ap->a_events & ~POLLSTANDARD)
  580                 return (vn_pollrecord(ap->a_vp, ap->a_td, ap->a_events));
  581         return (ap->a_events & (POLLIN | POLLOUT | POLLRDNORM | POLLWRNORM));
  582 }
  583 
  584 /*
  585  * Return our mount point, as we will take charge of the writes.
  586  */
  587 int
  588 vop_stdgetwritemount(ap)
  589         struct vop_getwritemount_args /* {
  590                 struct vnode *a_vp;
  591                 struct mount **a_mpp;
  592         } */ *ap;
  593 {
  594         struct mount *mp;
  595 
  596         /*
  597          * XXX Since this is called unlocked we may be recycled while
  598          * attempting to ref the mount.  If this is the case or mountpoint
  599          * will be set to NULL.  We only have to prevent this call from
  600          * returning with a ref to an incorrect mountpoint.  It is not
  601          * harmful to return with a ref to our previous mountpoint.
  602          */
  603         mp = ap->a_vp->v_mount;
  604         if (mp != NULL) {
  605                 vfs_ref(mp);
  606                 if (mp != ap->a_vp->v_mount) {
  607                         vfs_rel(mp);
  608                         mp = NULL;
  609                 }
  610         }
  611         *(ap->a_mpp) = mp;
  612         return (0);
  613 }
  614 
  615 /* XXX Needs good comment and VOP_BMAP(9) manpage */
  616 int
  617 vop_stdbmap(ap)
  618         struct vop_bmap_args /* {
  619                 struct vnode *a_vp;
  620                 daddr_t  a_bn;
  621                 struct bufobj **a_bop;
  622                 daddr_t *a_bnp;
  623                 int *a_runp;
  624                 int *a_runb;
  625         } */ *ap;
  626 {
  627 
  628         if (ap->a_bop != NULL)
  629                 *ap->a_bop = &ap->a_vp->v_bufobj;
  630         if (ap->a_bnp != NULL)
  631                 *ap->a_bnp = ap->a_bn * btodb(ap->a_vp->v_mount->mnt_stat.f_iosize);
  632         if (ap->a_runp != NULL)
  633                 *ap->a_runp = 0;
  634         if (ap->a_runb != NULL)
  635                 *ap->a_runb = 0;
  636         return (0);
  637 }
  638 
  639 int
  640 vop_stdfsync(ap)
  641         struct vop_fsync_args /* {
  642                 struct vnode *a_vp;
  643                 struct ucred *a_cred;
  644                 int a_waitfor;
  645                 struct thread *a_td;
  646         } */ *ap;
  647 {
  648         struct vnode *vp = ap->a_vp;
  649         struct buf *bp;
  650         struct bufobj *bo;
  651         struct buf *nbp;
  652         int error = 0;
  653         int maxretry = 1000;     /* large, arbitrarily chosen */
  654 
  655         bo = &vp->v_bufobj;
  656         BO_LOCK(bo);
  657 loop1:
  658         /*
  659          * MARK/SCAN initialization to avoid infinite loops.
  660          */
  661         TAILQ_FOREACH(bp, &bo->bo_dirty.bv_hd, b_bobufs) {
  662                 bp->b_vflags &= ~BV_SCANNED;
  663                 bp->b_error = 0;
  664         }
  665 
  666         /*
  667          * Flush all dirty buffers associated with a vnode.
  668          */
  669 loop2:
  670         TAILQ_FOREACH_SAFE(bp, &bo->bo_dirty.bv_hd, b_bobufs, nbp) {
  671                 if ((bp->b_vflags & BV_SCANNED) != 0)
  672                         continue;
  673                 bp->b_vflags |= BV_SCANNED;
  674                 if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT, NULL)) {
  675                         if (ap->a_waitfor != MNT_WAIT)
  676                                 continue;
  677                         if (BUF_LOCK(bp,
  678                             LK_EXCLUSIVE | LK_INTERLOCK | LK_SLEEPFAIL,
  679                             BO_LOCKPTR(bo)) != 0) {
  680                                 BO_LOCK(bo);
  681                                 goto loop1;
  682                         }
  683                         BO_LOCK(bo);
  684                 }
  685                 BO_UNLOCK(bo);
  686                 KASSERT(bp->b_bufobj == bo,
  687                     ("bp %p wrong b_bufobj %p should be %p",
  688                     bp, bp->b_bufobj, bo));
  689                 if ((bp->b_flags & B_DELWRI) == 0)
  690                         panic("fsync: not dirty");
  691                 if ((vp->v_object != NULL) && (bp->b_flags & B_CLUSTEROK)) {
  692                         vfs_bio_awrite(bp);
  693                 } else {
  694                         bremfree(bp);
  695                         bawrite(bp);
  696                 }
  697                 BO_LOCK(bo);
  698                 goto loop2;
  699         }
  700 
  701         /*
  702          * If synchronous the caller expects us to completely resolve all
  703          * dirty buffers in the system.  Wait for in-progress I/O to
  704          * complete (which could include background bitmap writes), then
  705          * retry if dirty blocks still exist.
  706          */
  707         if (ap->a_waitfor == MNT_WAIT) {
  708                 bufobj_wwait(bo, 0, 0);
  709                 if (bo->bo_dirty.bv_cnt > 0) {
  710                         /*
  711                          * If we are unable to write any of these buffers
  712                          * then we fail now rather than trying endlessly
  713                          * to write them out.
  714                          */
  715                         TAILQ_FOREACH(bp, &bo->bo_dirty.bv_hd, b_bobufs)
  716                                 if ((error = bp->b_error) == 0)
  717                                         continue;
  718                         if (error == 0 && --maxretry >= 0)
  719                                 goto loop1;
  720                         error = EAGAIN;
  721                 }
  722         }
  723         BO_UNLOCK(bo);
  724         if (error == EAGAIN)
  725                 vprint("fsync: giving up on dirty", vp);
  726 
  727         return (error);
  728 }
  729 
  730 /* XXX Needs good comment and more info in the manpage (VOP_GETPAGES(9)). */
  731 int
  732 vop_stdgetpages(ap)
  733         struct vop_getpages_args /* {
  734                 struct vnode *a_vp;
  735                 vm_page_t *a_m;
  736                 int a_count;
  737                 int *a_rbehind;
  738                 int *a_rahead;
  739         } */ *ap;
  740 {
  741 
  742         return vnode_pager_generic_getpages(ap->a_vp, ap->a_m,
  743             ap->a_count, ap->a_rbehind, ap->a_rahead, NULL, NULL);
  744 }
  745 
  746 static int
  747 vop_stdgetpages_async(struct vop_getpages_async_args *ap)
  748 {
  749         int error;
  750 
  751         error = VOP_GETPAGES(ap->a_vp, ap->a_m, ap->a_count, ap->a_rbehind,
  752             ap->a_rahead);
  753         ap->a_iodone(ap->a_arg, ap->a_m, ap->a_count, error);
  754         return (error);
  755 }
  756 
  757 int
  758 vop_stdkqfilter(struct vop_kqfilter_args *ap)
  759 {
  760         return vfs_kqfilter(ap);
  761 }
  762 
  763 /* XXX Needs good comment and more info in the manpage (VOP_PUTPAGES(9)). */
  764 int
  765 vop_stdputpages(ap)
  766         struct vop_putpages_args /* {
  767                 struct vnode *a_vp;
  768                 vm_page_t *a_m;
  769                 int a_count;
  770                 int a_sync;
  771                 int *a_rtvals;
  772         } */ *ap;
  773 {
  774 
  775         return vnode_pager_generic_putpages(ap->a_vp, ap->a_m, ap->a_count,
  776              ap->a_sync, ap->a_rtvals);
  777 }
  778 
  779 int
  780 vop_stdvptofh(struct vop_vptofh_args *ap)
  781 {
  782         return (EOPNOTSUPP);
  783 }
  784 
  785 int
  786 vop_stdvptocnp(struct vop_vptocnp_args *ap)
  787 {
  788         struct vnode *vp = ap->a_vp;
  789         struct vnode **dvp = ap->a_vpp;
  790         struct ucred *cred = ap->a_cred;
  791         char *buf = ap->a_buf;
  792         int *buflen = ap->a_buflen;
  793         char *dirbuf, *cpos;
  794         int i, error, eofflag, dirbuflen, flags, locked, len, covered;
  795         off_t off;
  796         ino_t fileno;
  797         struct vattr va;
  798         struct nameidata nd;
  799         struct thread *td;
  800         struct dirent *dp;
  801         struct vnode *mvp;
  802 
  803         i = *buflen;
  804         error = 0;
  805         covered = 0;
  806         td = curthread;
  807 
  808         if (vp->v_type != VDIR)
  809                 return (ENOENT);
  810 
  811         error = VOP_GETATTR(vp, &va, cred);
  812         if (error)
  813                 return (error);
  814 
  815         VREF(vp);
  816         locked = VOP_ISLOCKED(vp);
  817         VOP_UNLOCK(vp, 0);
  818         NDINIT_ATVP(&nd, LOOKUP, FOLLOW | LOCKSHARED | LOCKLEAF, UIO_SYSSPACE,
  819             "..", vp, td);
  820         flags = FREAD;
  821         error = vn_open_cred(&nd, &flags, 0, VN_OPEN_NOAUDIT, cred, NULL);
  822         if (error) {
  823                 vn_lock(vp, locked | LK_RETRY);
  824                 return (error);
  825         }
  826         NDFREE(&nd, NDF_ONLY_PNBUF);
  827 
  828         mvp = *dvp = nd.ni_vp;
  829 
  830         if (vp->v_mount != (*dvp)->v_mount &&
  831             ((*dvp)->v_vflag & VV_ROOT) &&
  832             ((*dvp)->v_mount->mnt_flag & MNT_UNION)) {
  833                 *dvp = (*dvp)->v_mount->mnt_vnodecovered;
  834                 VREF(mvp);
  835                 VOP_UNLOCK(mvp, 0);
  836                 vn_close(mvp, FREAD, cred, td);
  837                 VREF(*dvp);
  838                 vn_lock(*dvp, LK_SHARED | LK_RETRY);
  839                 covered = 1;
  840         }
  841 
  842         fileno = va.va_fileid;
  843 
  844         dirbuflen = DEV_BSIZE;
  845         if (dirbuflen < va.va_blocksize)
  846                 dirbuflen = va.va_blocksize;
  847         dirbuf = (char *)malloc(dirbuflen, M_TEMP, M_WAITOK);
  848 
  849         if ((*dvp)->v_type != VDIR) {
  850                 error = ENOENT;
  851                 goto out;
  852         }
  853 
  854         off = 0;
  855         len = 0;
  856         do {
  857                 /* call VOP_READDIR of parent */
  858                 error = get_next_dirent(*dvp, &dp, dirbuf, dirbuflen, &off,
  859                                         &cpos, &len, &eofflag, td);
  860                 if (error)
  861                         goto out;
  862 
  863                 if ((dp->d_type != DT_WHT) &&
  864                     (dp->d_fileno == fileno)) {
  865                         if (covered) {
  866                                 VOP_UNLOCK(*dvp, 0);
  867                                 vn_lock(mvp, LK_SHARED | LK_RETRY);
  868                                 if (dirent_exists(mvp, dp->d_name, td)) {
  869                                         error = ENOENT;
  870                                         VOP_UNLOCK(mvp, 0);
  871                                         vn_lock(*dvp, LK_SHARED | LK_RETRY);
  872                                         goto out;
  873                                 }
  874                                 VOP_UNLOCK(mvp, 0);
  875                                 vn_lock(*dvp, LK_SHARED | LK_RETRY);
  876                         }
  877                         i -= dp->d_namlen;
  878 
  879                         if (i < 0) {
  880                                 error = ENOMEM;
  881                                 goto out;
  882                         }
  883                         if (dp->d_namlen == 1 && dp->d_name[0] == '.') {
  884                                 error = ENOENT;
  885                         } else {
  886                                 bcopy(dp->d_name, buf + i, dp->d_namlen);
  887                                 error = 0;
  888                         }
  889                         goto out;
  890                 }
  891         } while (len > 0 || !eofflag);
  892         error = ENOENT;
  893 
  894 out:
  895         free(dirbuf, M_TEMP);
  896         if (!error) {
  897                 *buflen = i;
  898                 vref(*dvp);
  899         }
  900         if (covered) {
  901                 vput(*dvp);
  902                 vrele(mvp);
  903         } else {
  904                 VOP_UNLOCK(mvp, 0);
  905                 vn_close(mvp, FREAD, cred, td);
  906         }
  907         vn_lock(vp, locked | LK_RETRY);
  908         return (error);
  909 }
  910 
  911 int
  912 vop_stdallocate(struct vop_allocate_args *ap)
  913 {
  914 #ifdef __notyet__
  915         struct statfs sfs;
  916 #endif
  917         struct iovec aiov;
  918         struct vattr vattr, *vap;
  919         struct uio auio;
  920         off_t fsize, len, cur, offset;
  921         uint8_t *buf;
  922         struct thread *td;
  923         struct vnode *vp;
  924         size_t iosize;
  925         int error;
  926 
  927         buf = NULL;
  928         error = 0;
  929         td = curthread;
  930         vap = &vattr;
  931         vp = ap->a_vp;
  932         len = *ap->a_len;
  933         offset = *ap->a_offset;
  934 
  935         error = VOP_GETATTR(vp, vap, td->td_ucred);
  936         if (error != 0)
  937                 goto out;
  938         fsize = vap->va_size;
  939         iosize = vap->va_blocksize;
  940         if (iosize == 0)
  941                 iosize = BLKDEV_IOSIZE;
  942         if (iosize > MAXPHYS)
  943                 iosize = MAXPHYS;
  944         buf = malloc(iosize, M_TEMP, M_WAITOK);
  945 
  946 #ifdef __notyet__
  947         /*
  948          * Check if the filesystem sets f_maxfilesize; if not use
  949          * VOP_SETATTR to perform the check.
  950          */
  951         error = VFS_STATFS(vp->v_mount, &sfs, td);
  952         if (error != 0)
  953                 goto out;
  954         if (sfs.f_maxfilesize) {
  955                 if (offset > sfs.f_maxfilesize || len > sfs.f_maxfilesize ||
  956                     offset + len > sfs.f_maxfilesize) {
  957                         error = EFBIG;
  958                         goto out;
  959                 }
  960         } else
  961 #endif
  962         if (offset + len > vap->va_size) {
  963                 /*
  964                  * Test offset + len against the filesystem's maxfilesize.
  965                  */
  966                 VATTR_NULL(vap);
  967                 vap->va_size = offset + len;
  968                 error = VOP_SETATTR(vp, vap, td->td_ucred);
  969                 if (error != 0)
  970                         goto out;
  971                 VATTR_NULL(vap);
  972                 vap->va_size = fsize;
  973                 error = VOP_SETATTR(vp, vap, td->td_ucred);
  974                 if (error != 0)
  975                         goto out;
  976         }
  977 
  978         for (;;) {
  979                 /*
  980                  * Read and write back anything below the nominal file
  981                  * size.  There's currently no way outside the filesystem
  982                  * to know whether this area is sparse or not.
  983                  */
  984                 cur = iosize;
  985                 if ((offset % iosize) != 0)
  986                         cur -= (offset % iosize);
  987                 if (cur > len)
  988                         cur = len;
  989                 if (offset < fsize) {
  990                         aiov.iov_base = buf;
  991                         aiov.iov_len = cur;
  992                         auio.uio_iov = &aiov;
  993                         auio.uio_iovcnt = 1;
  994                         auio.uio_offset = offset;
  995                         auio.uio_resid = cur;
  996                         auio.uio_segflg = UIO_SYSSPACE;
  997                         auio.uio_rw = UIO_READ;
  998                         auio.uio_td = td;
  999                         error = VOP_READ(vp, &auio, 0, td->td_ucred);
 1000                         if (error != 0)
 1001                                 break;
 1002                         if (auio.uio_resid > 0) {
 1003                                 bzero(buf + cur - auio.uio_resid,
 1004                                     auio.uio_resid);
 1005                         }
 1006                 } else {
 1007                         bzero(buf, cur);
 1008                 }
 1009 
 1010                 aiov.iov_base = buf;
 1011                 aiov.iov_len = cur;
 1012                 auio.uio_iov = &aiov;
 1013                 auio.uio_iovcnt = 1;
 1014                 auio.uio_offset = offset;
 1015                 auio.uio_resid = cur;
 1016                 auio.uio_segflg = UIO_SYSSPACE;
 1017                 auio.uio_rw = UIO_WRITE;
 1018                 auio.uio_td = td;
 1019 
 1020                 error = VOP_WRITE(vp, &auio, 0, td->td_ucred);
 1021                 if (error != 0)
 1022                         break;
 1023 
 1024                 len -= cur;
 1025                 offset += cur;
 1026                 if (len == 0)
 1027                         break;
 1028                 if (should_yield())
 1029                         break;
 1030         }
 1031 
 1032  out:
 1033         *ap->a_len = len;
 1034         *ap->a_offset = offset;
 1035         free(buf, M_TEMP);
 1036         return (error);
 1037 }
 1038 
 1039 int
 1040 vop_stdadvise(struct vop_advise_args *ap)
 1041 {
 1042         struct vnode *vp;
 1043         struct bufobj *bo;
 1044         daddr_t startn, endn;
 1045         off_t start, end;
 1046         int bsize, error;
 1047 
 1048         vp = ap->a_vp;
 1049         switch (ap->a_advice) {
 1050         case POSIX_FADV_WILLNEED:
 1051                 /*
 1052                  * Do nothing for now.  Filesystems should provide a
 1053                  * custom method which starts an asynchronous read of
 1054                  * the requested region.
 1055                  */
 1056                 error = 0;
 1057                 break;
 1058         case POSIX_FADV_DONTNEED:
 1059                 error = 0;
 1060                 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
 1061                 if (vp->v_iflag & VI_DOOMED) {
 1062                         VOP_UNLOCK(vp, 0);
 1063                         break;
 1064                 }
 1065 
 1066                 /*
 1067                  * Deactivate pages in the specified range from the backing VM
 1068                  * object.  Pages that are resident in the buffer cache will
 1069                  * remain wired until their corresponding buffers are released
 1070                  * below.
 1071                  */
 1072                 if (vp->v_object != NULL) {
 1073                         start = trunc_page(ap->a_start);
 1074                         end = round_page(ap->a_end);
 1075                         VM_OBJECT_WLOCK(vp->v_object);
 1076                         vm_object_page_noreuse(vp->v_object, OFF_TO_IDX(start),
 1077                             OFF_TO_IDX(end));
 1078                         VM_OBJECT_WUNLOCK(vp->v_object);
 1079                 }
 1080 
 1081                 bo = &vp->v_bufobj;
 1082                 BO_RLOCK(bo);
 1083                 bsize = vp->v_bufobj.bo_bsize;
 1084                 startn = ap->a_start / bsize;
 1085                 endn = ap->a_end / bsize;
 1086                 error = bnoreuselist(&bo->bo_clean, bo, startn, endn);
 1087                 if (error == 0)
 1088                         error = bnoreuselist(&bo->bo_dirty, bo, startn, endn);
 1089                 BO_RUNLOCK(bo);
 1090                 VOP_UNLOCK(vp, 0);
 1091                 break;
 1092         default:
 1093                 error = EINVAL;
 1094                 break;
 1095         }
 1096         return (error);
 1097 }
 1098 
 1099 int
 1100 vop_stdunp_bind(struct vop_unp_bind_args *ap)
 1101 {
 1102 
 1103         ap->a_vp->v_socket = ap->a_socket;
 1104         return (0);
 1105 }
 1106 
 1107 int
 1108 vop_stdunp_connect(struct vop_unp_connect_args *ap)
 1109 {
 1110 
 1111         *ap->a_socket = ap->a_vp->v_socket;
 1112         return (0);
 1113 }
 1114 
 1115 int
 1116 vop_stdunp_detach(struct vop_unp_detach_args *ap)
 1117 {
 1118 
 1119         ap->a_vp->v_socket = NULL;
 1120         return (0);
 1121 }
 1122 
 1123 static int
 1124 vop_stdis_text(struct vop_is_text_args *ap)
 1125 {
 1126 
 1127         return ((ap->a_vp->v_vflag & VV_TEXT) != 0);
 1128 }
 1129 
 1130 static int
 1131 vop_stdset_text(struct vop_set_text_args *ap)
 1132 {
 1133 
 1134         ap->a_vp->v_vflag |= VV_TEXT;
 1135         return (0);
 1136 }
 1137 
 1138 static int
 1139 vop_stdunset_text(struct vop_unset_text_args *ap)
 1140 {
 1141 
 1142         ap->a_vp->v_vflag &= ~VV_TEXT;
 1143         return (0);
 1144 }
 1145 
 1146 static int
 1147 vop_stdget_writecount(struct vop_get_writecount_args *ap)
 1148 {
 1149 
 1150         *ap->a_writecount = ap->a_vp->v_writecount;
 1151         return (0);
 1152 }
 1153 
 1154 static int
 1155 vop_stdadd_writecount(struct vop_add_writecount_args *ap)
 1156 {
 1157 
 1158         ap->a_vp->v_writecount += ap->a_inc;
 1159         return (0);
 1160 }
 1161 
 1162 /*
 1163  * vfs default ops
 1164  * used to fill the vfs function table to get reasonable default return values.
 1165  */
 1166 int
 1167 vfs_stdroot (mp, flags, vpp)
 1168         struct mount *mp;
 1169         int flags;
 1170         struct vnode **vpp;
 1171 {
 1172 
 1173         return (EOPNOTSUPP);
 1174 }
 1175 
 1176 int
 1177 vfs_stdstatfs (mp, sbp)
 1178         struct mount *mp;
 1179         struct statfs *sbp;
 1180 {
 1181 
 1182         return (EOPNOTSUPP);
 1183 }
 1184 
 1185 int
 1186 vfs_stdquotactl (mp, cmds, uid, arg)
 1187         struct mount *mp;
 1188         int cmds;
 1189         uid_t uid;
 1190         void *arg;
 1191 {
 1192 
 1193         return (EOPNOTSUPP);
 1194 }
 1195 
 1196 int
 1197 vfs_stdsync(mp, waitfor)
 1198         struct mount *mp;
 1199         int waitfor;
 1200 {
 1201         struct vnode *vp, *mvp;
 1202         struct thread *td;
 1203         int error, lockreq, allerror = 0;
 1204 
 1205         td = curthread;
 1206         lockreq = LK_EXCLUSIVE | LK_INTERLOCK;
 1207         if (waitfor != MNT_WAIT)
 1208                 lockreq |= LK_NOWAIT;
 1209         /*
 1210          * Force stale buffer cache information to be flushed.
 1211          */
 1212 loop:
 1213         MNT_VNODE_FOREACH_ALL(vp, mp, mvp) {
 1214                 if (vp->v_bufobj.bo_dirty.bv_cnt == 0) {
 1215                         VI_UNLOCK(vp);
 1216                         continue;
 1217                 }
 1218                 if ((error = vget(vp, lockreq, td)) != 0) {
 1219                         if (error == ENOENT) {
 1220                                 MNT_VNODE_FOREACH_ALL_ABORT(mp, mvp);
 1221                                 goto loop;
 1222                         }
 1223                         continue;
 1224                 }
 1225                 error = VOP_FSYNC(vp, waitfor, td);
 1226                 if (error)
 1227                         allerror = error;
 1228                 vput(vp);
 1229         }
 1230         return (allerror);
 1231 }
 1232 
 1233 int
 1234 vfs_stdnosync (mp, waitfor)
 1235         struct mount *mp;
 1236         int waitfor;
 1237 {
 1238 
 1239         return (0);
 1240 }
 1241 
 1242 int
 1243 vfs_stdvget (mp, ino, flags, vpp)
 1244         struct mount *mp;
 1245         ino_t ino;
 1246         int flags;
 1247         struct vnode **vpp;
 1248 {
 1249 
 1250         return (EOPNOTSUPP);
 1251 }
 1252 
 1253 int
 1254 vfs_stdfhtovp (mp, fhp, flags, vpp)
 1255         struct mount *mp;
 1256         struct fid *fhp;
 1257         int flags;
 1258         struct vnode **vpp;
 1259 {
 1260 
 1261         return (EOPNOTSUPP);
 1262 }
 1263 
 1264 int
 1265 vfs_stdinit (vfsp)
 1266         struct vfsconf *vfsp;
 1267 {
 1268 
 1269         return (0);
 1270 }
 1271 
 1272 int
 1273 vfs_stduninit (vfsp)
 1274         struct vfsconf *vfsp;
 1275 {
 1276 
 1277         return(0);
 1278 }
 1279 
 1280 int
 1281 vfs_stdextattrctl(mp, cmd, filename_vp, attrnamespace, attrname)
 1282         struct mount *mp;
 1283         int cmd;
 1284         struct vnode *filename_vp;
 1285         int attrnamespace;
 1286         const char *attrname;
 1287 {
 1288 
 1289         if (filename_vp != NULL)
 1290                 VOP_UNLOCK(filename_vp, 0);
 1291         return (EOPNOTSUPP);
 1292 }
 1293 
 1294 int
 1295 vfs_stdsysctl(mp, op, req)
 1296         struct mount *mp;
 1297         fsctlop_t op;
 1298         struct sysctl_req *req;
 1299 {
 1300 
 1301         return (EOPNOTSUPP);
 1302 }
 1303 
 1304 /* end of vfs default ops */

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