tmpfs_subr.c

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    1 /*      $NetBSD: tmpfs_subr.c,v 1.35 2007/07/09 21:10:50 ad Exp $       */
    2 
    3 /*-
    4  * Copyright (c) 2005 The NetBSD Foundation, Inc.
    5  * All rights reserved.
    6  *
    7  * This code is derived from software contributed to The NetBSD Foundation
    8  * by Julio M. Merino Vidal, developed as part of Google's Summer of Code
    9  * 2005 program.
   10  *
   11  * Redistribution and use in source and binary forms, with or without
   12  * modification, are permitted provided that the following conditions
   13  * are met:
   14  * 1. Redistributions of source code must retain the above copyright
   15  *    notice, this list of conditions and the following disclaimer.
   16  * 2. Redistributions in binary form must reproduce the above copyright
   17  *    notice, this list of conditions and the following disclaimer in the
   18  *    documentation and/or other materials provided with the distribution.
   19  *
   20  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
   21  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
   22  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
   23  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
   24  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
   25  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
   26  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
   27  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
   28  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
   29  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
   30  * POSSIBILITY OF SUCH DAMAGE.
   31  */
   32 
   33 /*
   34  * Efficient memory file system supporting functions.
   35  */
   36 #include <sys/cdefs.h>
   37 __FBSDID("$FreeBSD: releng/8.0/sys/fs/tmpfs/tmpfs_subr.c 194766 2009-06-23 20:45:22Z kib $");
   38 
   39 #include <sys/param.h>
   40 #include <sys/namei.h>
   41 #include <sys/priv.h>
   42 #include <sys/proc.h>
   43 #include <sys/stat.h>
   44 #include <sys/systm.h>
   45 #include <sys/vnode.h>
   46 #include <sys/vmmeter.h>
   47 
   48 #include <vm/vm.h>
   49 #include <vm/vm_object.h>
   50 #include <vm/vm_page.h>
   51 #include <vm/vm_pager.h>
   52 #include <vm/vm_extern.h>
   53 
   54 #include <fs/tmpfs/tmpfs.h>
   55 #include <fs/tmpfs/tmpfs_fifoops.h>
   56 #include <fs/tmpfs/tmpfs_vnops.h>
   57 
   58 /* --------------------------------------------------------------------- */
   59 
   60 /*
   61  * Allocates a new node of type 'type' inside the 'tmp' mount point, with
   62  * its owner set to 'uid', its group to 'gid' and its mode set to 'mode',
   63  * using the credentials of the process 'p'.
   64  *
   65  * If the node type is set to 'VDIR', then the parent parameter must point
   66  * to the parent directory of the node being created.  It may only be NULL
   67  * while allocating the root node.
   68  *
   69  * If the node type is set to 'VBLK' or 'VCHR', then the rdev parameter
   70  * specifies the device the node represents.
   71  *
   72  * If the node type is set to 'VLNK', then the parameter target specifies
   73  * the file name of the target file for the symbolic link that is being
   74  * created.
   75  *
   76  * Note that new nodes are retrieved from the available list if it has
   77  * items or, if it is empty, from the node pool as long as there is enough
   78  * space to create them.
   79  *
   80  * Returns zero on success or an appropriate error code on failure.
   81  */
   82 int
   83 tmpfs_alloc_node(struct tmpfs_mount *tmp, enum vtype type,
   84     uid_t uid, gid_t gid, mode_t mode, struct tmpfs_node *parent,
   85     char *target, dev_t rdev, struct tmpfs_node **node)
   86 {
   87         struct tmpfs_node *nnode;
   88 
   89         /* If the root directory of the 'tmp' file system is not yet
   90          * allocated, this must be the request to do it. */
   91         MPASS(IMPLIES(tmp->tm_root == NULL, parent == NULL && type == VDIR));
   92 
   93         MPASS(IFF(type == VLNK, target != NULL));
   94         MPASS(IFF(type == VBLK || type == VCHR, rdev != VNOVAL));
   95 
   96         if (tmp->tm_nodes_inuse > tmp->tm_nodes_max)
   97                 return (ENOSPC);
   98 
   99         nnode = (struct tmpfs_node *)uma_zalloc_arg(
  100                                 tmp->tm_node_pool, tmp, M_WAITOK);
  101 
  102         /* Generic initialization. */
  103         nnode->tn_type = type;
  104         vfs_timestamp(&nnode->tn_atime);
  105         nnode->tn_birthtime = nnode->tn_ctime = nnode->tn_mtime =
  106             nnode->tn_atime;
  107         nnode->tn_uid = uid;
  108         nnode->tn_gid = gid;
  109         nnode->tn_mode = mode;
  110         nnode->tn_id = alloc_unr(tmp->tm_ino_unr);
  111 
  112         /* Type-specific initialization. */
  113         switch (nnode->tn_type) {
  114         case VBLK:
  115         case VCHR:
  116                 nnode->tn_rdev = rdev;
  117                 break;
  118 
  119         case VDIR:
  120                 TAILQ_INIT(&nnode->tn_dir.tn_dirhead);
  121                 MPASS(parent != nnode);
  122                 MPASS(IMPLIES(parent == NULL, tmp->tm_root == NULL));
  123                 nnode->tn_dir.tn_parent = (parent == NULL) ? nnode : parent;
  124                 nnode->tn_dir.tn_readdir_lastn = 0;
  125                 nnode->tn_dir.tn_readdir_lastp = NULL;
  126                 nnode->tn_links++;
  127                 nnode->tn_dir.tn_parent->tn_links++;
  128                 break;
  129 
  130         case VFIFO:
  131                 /* FALLTHROUGH */
  132         case VSOCK:
  133                 break;
  134 
  135         case VLNK:
  136                 MPASS(strlen(target) < MAXPATHLEN);
  137                 nnode->tn_size = strlen(target);
  138                 nnode->tn_link = malloc(nnode->tn_size, M_TMPFSNAME,
  139                     M_WAITOK);
  140                 memcpy(nnode->tn_link, target, nnode->tn_size);
  141                 break;
  142 
  143         case VREG:
  144                 nnode->tn_reg.tn_aobj =
  145                     vm_pager_allocate(OBJT_SWAP, NULL, 0, VM_PROT_DEFAULT, 0,
  146                         NULL /* XXXKIB - tmpfs needs swap reservation */);
  147                 nnode->tn_reg.tn_aobj_pages = 0;
  148                 break;
  149 
  150         default:
  151                 panic("tmpfs_alloc_node: type %p %d", nnode, (int)nnode->tn_type);
  152         }
  153 
  154         TMPFS_LOCK(tmp);
  155         LIST_INSERT_HEAD(&tmp->tm_nodes_used, nnode, tn_entries);
  156         tmp->tm_nodes_inuse++;
  157         TMPFS_UNLOCK(tmp);
  158 
  159         *node = nnode;
  160         return 0;
  161 }
  162 
  163 /* --------------------------------------------------------------------- */
  164 
  165 /*
  166  * Destroys the node pointed to by node from the file system 'tmp'.
  167  * If the node does not belong to the given mount point, the results are
  168  * unpredicted.
  169  *
  170  * If the node references a directory; no entries are allowed because
  171  * their removal could need a recursive algorithm, something forbidden in
  172  * kernel space.  Furthermore, there is not need to provide such
  173  * functionality (recursive removal) because the only primitives offered
  174  * to the user are the removal of empty directories and the deletion of
  175  * individual files.
  176  *
  177  * Note that nodes are not really deleted; in fact, when a node has been
  178  * allocated, it cannot be deleted during the whole life of the file
  179  * system.  Instead, they are moved to the available list and remain there
  180  * until reused.
  181  */
  182 void
  183 tmpfs_free_node(struct tmpfs_mount *tmp, struct tmpfs_node *node)
  184 {
  185         size_t pages = 0;
  186 
  187 #ifdef INVARIANTS
  188         TMPFS_NODE_LOCK(node);
  189         MPASS(node->tn_vnode == NULL);
  190         TMPFS_NODE_UNLOCK(node);
  191 #endif
  192 
  193         TMPFS_LOCK(tmp);
  194         LIST_REMOVE(node, tn_entries);
  195         tmp->tm_nodes_inuse--;
  196         TMPFS_UNLOCK(tmp);
  197 
  198         switch (node->tn_type) {
  199         case VNON:
  200                 /* Do not do anything.  VNON is provided to let the
  201                  * allocation routine clean itself easily by avoiding
  202                  * duplicating code in it. */
  203                 /* FALLTHROUGH */
  204         case VBLK:
  205                 /* FALLTHROUGH */
  206         case VCHR:
  207                 /* FALLTHROUGH */
  208         case VDIR:
  209                 /* FALLTHROUGH */
  210         case VFIFO:
  211                 /* FALLTHROUGH */
  212         case VSOCK:
  213                 break;
  214 
  215         case VLNK:
  216                 free(node->tn_link, M_TMPFSNAME);
  217                 break;
  218 
  219         case VREG:
  220                 if (node->tn_reg.tn_aobj != NULL)
  221                         vm_object_deallocate(node->tn_reg.tn_aobj);
  222                 pages = node->tn_reg.tn_aobj_pages;
  223                 break;
  224 
  225         default:
  226                 panic("tmpfs_free_node: type %p %d", node, (int)node->tn_type);
  227         }
  228 
  229         free_unr(tmp->tm_ino_unr, node->tn_id);
  230         uma_zfree(tmp->tm_node_pool, node);
  231 
  232         TMPFS_LOCK(tmp);
  233         tmp->tm_pages_used -= pages;
  234         TMPFS_UNLOCK(tmp);
  235 }
  236 
  237 /* --------------------------------------------------------------------- */
  238 
  239 /*
  240  * Allocates a new directory entry for the node node with a name of name.
  241  * The new directory entry is returned in *de.
  242  *
  243  * The link count of node is increased by one to reflect the new object
  244  * referencing it.
  245  *
  246  * Returns zero on success or an appropriate error code on failure.
  247  */
  248 int
  249 tmpfs_alloc_dirent(struct tmpfs_mount *tmp, struct tmpfs_node *node,
  250     const char *name, uint16_t len, struct tmpfs_dirent **de)
  251 {
  252         struct tmpfs_dirent *nde;
  253 
  254         nde = (struct tmpfs_dirent *)uma_zalloc(
  255                                         tmp->tm_dirent_pool, M_WAITOK);
  256         nde->td_name = malloc(len, M_TMPFSNAME, M_WAITOK);
  257         nde->td_namelen = len;
  258         memcpy(nde->td_name, name, len);
  259 
  260         nde->td_node = node;
  261         node->tn_links++;
  262 
  263         *de = nde;
  264 
  265         return 0;
  266 }
  267 
  268 /* --------------------------------------------------------------------- */
  269 
  270 /*
  271  * Frees a directory entry.  It is the caller's responsibility to destroy
  272  * the node referenced by it if needed.
  273  *
  274  * The link count of node is decreased by one to reflect the removal of an
  275  * object that referenced it.  This only happens if 'node_exists' is true;
  276  * otherwise the function will not access the node referred to by the
  277  * directory entry, as it may already have been released from the outside.
  278  */
  279 void
  280 tmpfs_free_dirent(struct tmpfs_mount *tmp, struct tmpfs_dirent *de,
  281     boolean_t node_exists)
  282 {
  283         if (node_exists) {
  284                 struct tmpfs_node *node;
  285 
  286                 node = de->td_node;
  287 
  288                 MPASS(node->tn_links > 0);
  289                 node->tn_links--;
  290         }
  291 
  292         free(de->td_name, M_TMPFSNAME);
  293         uma_zfree(tmp->tm_dirent_pool, de);
  294 }
  295 
  296 /* --------------------------------------------------------------------- */
  297 
  298 /*
  299  * Allocates a new vnode for the node node or returns a new reference to
  300  * an existing one if the node had already a vnode referencing it.  The
  301  * resulting locked vnode is returned in *vpp.
  302  *
  303  * Returns zero on success or an appropriate error code on failure.
  304  */
  305 int
  306 tmpfs_alloc_vp(struct mount *mp, struct tmpfs_node *node, int lkflag,
  307     struct vnode **vpp)
  308 {
  309         int error = 0;
  310         struct vnode *vp;
  311 
  312 loop:
  313         TMPFS_NODE_LOCK(node);
  314         if ((vp = node->tn_vnode) != NULL) {
  315                 VI_LOCK(vp);
  316                 TMPFS_NODE_UNLOCK(node);
  317                 vholdl(vp);
  318                 (void) vget(vp, lkflag | LK_INTERLOCK | LK_RETRY, curthread);
  319                 vdrop(vp);
  320 
  321                 /*
  322                  * Make sure the vnode is still there after
  323                  * getting the interlock to avoid racing a free.
  324                  */
  325                 if (node->tn_vnode == NULL || node->tn_vnode != vp) {
  326                         vput(vp);
  327                         goto loop;
  328                 }
  329 
  330                 goto out;
  331         }
  332 
  333         /*
  334          * otherwise lock the vp list while we call getnewvnode
  335          * since that can block.
  336          */
  337         if (node->tn_vpstate & TMPFS_VNODE_ALLOCATING) {
  338                 node->tn_vpstate |= TMPFS_VNODE_WANT;
  339                 error = msleep((caddr_t) &node->tn_vpstate,
  340                     TMPFS_NODE_MTX(node), PDROP | PCATCH,
  341                     "tmpfs_alloc_vp", 0);
  342                 if (error)
  343                         return error;
  344 
  345                 goto loop;
  346         } else
  347                 node->tn_vpstate |= TMPFS_VNODE_ALLOCATING;
  348         
  349         TMPFS_NODE_UNLOCK(node);
  350 
  351         /* Get a new vnode and associate it with our node. */
  352         error = getnewvnode("tmpfs", mp, &tmpfs_vnodeop_entries, &vp);
  353         if (error != 0)
  354                 goto unlock;
  355         MPASS(vp != NULL);
  356 
  357         (void) vn_lock(vp, lkflag | LK_RETRY);
  358 
  359         vp->v_data = node;
  360         vp->v_type = node->tn_type;
  361 
  362         /* Type-specific initialization. */
  363         switch (node->tn_type) {
  364         case VBLK:
  365                 /* FALLTHROUGH */
  366         case VCHR:
  367                 /* FALLTHROUGH */
  368         case VLNK:
  369                 /* FALLTHROUGH */
  370         case VREG:
  371                 /* FALLTHROUGH */
  372         case VSOCK:
  373                 break;
  374         case VFIFO:
  375                 vp->v_op = &tmpfs_fifoop_entries;
  376                 break;
  377         case VDIR:
  378                 if (node->tn_dir.tn_parent == node)
  379                         vp->v_vflag |= VV_ROOT;
  380                 break;
  381 
  382         default:
  383                 panic("tmpfs_alloc_vp: type %p %d", node, (int)node->tn_type);
  384         }
  385 
  386         vnode_pager_setsize(vp, node->tn_size);
  387         error = insmntque(vp, mp);
  388         if (error)
  389                 vp = NULL;
  390 
  391 unlock:
  392         TMPFS_NODE_LOCK(node);
  393 
  394         MPASS(node->tn_vpstate & TMPFS_VNODE_ALLOCATING);
  395         node->tn_vpstate &= ~TMPFS_VNODE_ALLOCATING;
  396         node->tn_vnode = vp;
  397 
  398         if (node->tn_vpstate & TMPFS_VNODE_WANT) {
  399                 node->tn_vpstate &= ~TMPFS_VNODE_WANT;
  400                 TMPFS_NODE_UNLOCK(node);
  401                 wakeup((caddr_t) &node->tn_vpstate);
  402         } else
  403                 TMPFS_NODE_UNLOCK(node);
  404 
  405 out:
  406         *vpp = vp;
  407 
  408         MPASS(IFF(error == 0, *vpp != NULL && VOP_ISLOCKED(*vpp)));
  409 #ifdef INVARIANTS
  410         TMPFS_NODE_LOCK(node);
  411         MPASS(*vpp == node->tn_vnode);
  412         TMPFS_NODE_UNLOCK(node);
  413 #endif
  414 
  415         return error;
  416 }
  417 
  418 /* --------------------------------------------------------------------- */
  419 
  420 /*
  421  * Destroys the association between the vnode vp and the node it
  422  * references.
  423  */
  424 void
  425 tmpfs_free_vp(struct vnode *vp)
  426 {
  427         struct tmpfs_node *node;
  428 
  429         node = VP_TO_TMPFS_NODE(vp);
  430 
  431         TMPFS_NODE_LOCK(node);
  432         node->tn_vnode = NULL;
  433         vp->v_data = NULL;
  434         TMPFS_NODE_UNLOCK(node);
  435 }
  436 
  437 /* --------------------------------------------------------------------- */
  438 
  439 /*
  440  * Allocates a new file of type 'type' and adds it to the parent directory
  441  * 'dvp'; this addition is done using the component name given in 'cnp'.
  442  * The ownership of the new file is automatically assigned based on the
  443  * credentials of the caller (through 'cnp'), the group is set based on
  444  * the parent directory and the mode is determined from the 'vap' argument.
  445  * If successful, *vpp holds a vnode to the newly created file and zero
  446  * is returned.  Otherwise *vpp is NULL and the function returns an
  447  * appropriate error code.
  448  */
  449 int
  450 tmpfs_alloc_file(struct vnode *dvp, struct vnode **vpp, struct vattr *vap,
  451     struct componentname *cnp, char *target)
  452 {
  453         int error;
  454         struct tmpfs_dirent *de;
  455         struct tmpfs_mount *tmp;
  456         struct tmpfs_node *dnode;
  457         struct tmpfs_node *node;
  458         struct tmpfs_node *parent;
  459 
  460         MPASS(VOP_ISLOCKED(dvp));
  461         MPASS(cnp->cn_flags & HASBUF);
  462 
  463         tmp = VFS_TO_TMPFS(dvp->v_mount);
  464         dnode = VP_TO_TMPFS_DIR(dvp);
  465         *vpp = NULL;
  466 
  467         /* If the entry we are creating is a directory, we cannot overflow
  468          * the number of links of its parent, because it will get a new
  469          * link. */
  470         if (vap->va_type == VDIR) {
  471                 /* Ensure that we do not overflow the maximum number of links
  472                  * imposed by the system. */
  473                 MPASS(dnode->tn_links <= LINK_MAX);
  474                 if (dnode->tn_links == LINK_MAX) {
  475                         error = EMLINK;
  476                         goto out;
  477                 }
  478 
  479                 parent = dnode;
  480                 MPASS(parent != NULL);
  481         } else
  482                 parent = NULL;
  483 
  484         /* Allocate a node that represents the new file. */
  485         error = tmpfs_alloc_node(tmp, vap->va_type, cnp->cn_cred->cr_uid,
  486             dnode->tn_gid, vap->va_mode, parent, target, vap->va_rdev, &node);
  487         if (error != 0)
  488                 goto out;
  489 
  490         /* Allocate a directory entry that points to the new file. */
  491         error = tmpfs_alloc_dirent(tmp, node, cnp->cn_nameptr, cnp->cn_namelen,
  492             &de);
  493         if (error != 0) {
  494                 tmpfs_free_node(tmp, node);
  495                 goto out;
  496         }
  497 
  498         /* Allocate a vnode for the new file. */
  499         error = tmpfs_alloc_vp(dvp->v_mount, node, LK_EXCLUSIVE, vpp);
  500         if (error != 0) {
  501                 tmpfs_free_dirent(tmp, de, TRUE);
  502                 tmpfs_free_node(tmp, node);
  503                 goto out;
  504         }
  505 
  506         /* Now that all required items are allocated, we can proceed to
  507          * insert the new node into the directory, an operation that
  508          * cannot fail. */
  509         tmpfs_dir_attach(dvp, de);
  510 
  511 out:
  512 
  513         return error;
  514 }
  515 
  516 /* --------------------------------------------------------------------- */
  517 
  518 /*
  519  * Attaches the directory entry de to the directory represented by vp.
  520  * Note that this does not change the link count of the node pointed by
  521  * the directory entry, as this is done by tmpfs_alloc_dirent.
  522  */
  523 void
  524 tmpfs_dir_attach(struct vnode *vp, struct tmpfs_dirent *de)
  525 {
  526         struct tmpfs_node *dnode;
  527 
  528         ASSERT_VOP_ELOCKED(vp, __func__);
  529         dnode = VP_TO_TMPFS_DIR(vp);
  530         TAILQ_INSERT_TAIL(&dnode->tn_dir.tn_dirhead, de, td_entries);
  531         dnode->tn_size += sizeof(struct tmpfs_dirent);
  532         dnode->tn_status |= TMPFS_NODE_ACCESSED | TMPFS_NODE_CHANGED | \
  533             TMPFS_NODE_MODIFIED;
  534 }
  535 
  536 /* --------------------------------------------------------------------- */
  537 
  538 /*
  539  * Detaches the directory entry de from the directory represented by vp.
  540  * Note that this does not change the link count of the node pointed by
  541  * the directory entry, as this is done by tmpfs_free_dirent.
  542  */
  543 void
  544 tmpfs_dir_detach(struct vnode *vp, struct tmpfs_dirent *de)
  545 {
  546         struct tmpfs_node *dnode;
  547 
  548         ASSERT_VOP_ELOCKED(vp, __func__);
  549         dnode = VP_TO_TMPFS_DIR(vp);
  550 
  551         if (dnode->tn_dir.tn_readdir_lastp == de) {
  552                 dnode->tn_dir.tn_readdir_lastn = 0;
  553                 dnode->tn_dir.tn_readdir_lastp = NULL;
  554         }
  555 
  556         TAILQ_REMOVE(&dnode->tn_dir.tn_dirhead, de, td_entries);
  557         dnode->tn_size -= sizeof(struct tmpfs_dirent);
  558         dnode->tn_status |= TMPFS_NODE_ACCESSED | TMPFS_NODE_CHANGED | \
  559             TMPFS_NODE_MODIFIED;
  560 }
  561 
  562 /* --------------------------------------------------------------------- */
  563 
  564 /*
  565  * Looks for a directory entry in the directory represented by node.
  566  * 'cnp' describes the name of the entry to look for.  Note that the .
  567  * and .. components are not allowed as they do not physically exist
  568  * within directories.
  569  *
  570  * Returns a pointer to the entry when found, otherwise NULL.
  571  */
  572 struct tmpfs_dirent *
  573 tmpfs_dir_lookup(struct tmpfs_node *node, struct tmpfs_node *f,
  574     struct componentname *cnp)
  575 {
  576         boolean_t found;
  577         struct tmpfs_dirent *de;
  578 
  579         MPASS(IMPLIES(cnp->cn_namelen == 1, cnp->cn_nameptr[0] != '.'));
  580         MPASS(IMPLIES(cnp->cn_namelen == 2, !(cnp->cn_nameptr[0] == '.' &&
  581             cnp->cn_nameptr[1] == '.')));
  582         TMPFS_VALIDATE_DIR(node);
  583 
  584         found = 0;
  585         TAILQ_FOREACH(de, &node->tn_dir.tn_dirhead, td_entries) {
  586                 if (f != NULL && de->td_node != f)
  587                     continue;
  588                 MPASS(cnp->cn_namelen < 0xffff);
  589                 if (de->td_namelen == (uint16_t)cnp->cn_namelen &&
  590                     bcmp(de->td_name, cnp->cn_nameptr, de->td_namelen) == 0) {
  591                         found = 1;
  592                         break;
  593                 }
  594         }
  595         node->tn_status |= TMPFS_NODE_ACCESSED;
  596 
  597         return found ? de : NULL;
  598 }
  599 
  600 /* --------------------------------------------------------------------- */
  601 
  602 /*
  603  * Helper function for tmpfs_readdir.  Creates a '.' entry for the given
  604  * directory and returns it in the uio space.  The function returns 0
  605  * on success, -1 if there was not enough space in the uio structure to
  606  * hold the directory entry or an appropriate error code if another
  607  * error happens.
  608  */
  609 int
  610 tmpfs_dir_getdotdent(struct tmpfs_node *node, struct uio *uio)
  611 {
  612         int error;
  613         struct dirent dent;
  614 
  615         TMPFS_VALIDATE_DIR(node);
  616         MPASS(uio->uio_offset == TMPFS_DIRCOOKIE_DOT);
  617 
  618         dent.d_fileno = node->tn_id;
  619         dent.d_type = DT_DIR;
  620         dent.d_namlen = 1;
  621         dent.d_name[0] = '.';
  622         dent.d_name[1] = '\0';
  623         dent.d_reclen = GENERIC_DIRSIZ(&dent);
  624 
  625         if (dent.d_reclen > uio->uio_resid)
  626                 error = -1;
  627         else {
  628                 error = uiomove(&dent, dent.d_reclen, uio);
  629                 if (error == 0)
  630                         uio->uio_offset = TMPFS_DIRCOOKIE_DOTDOT;
  631         }
  632 
  633         node->tn_status |= TMPFS_NODE_ACCESSED;
  634 
  635         return error;
  636 }
  637 
  638 /* --------------------------------------------------------------------- */
  639 
  640 /*
  641  * Helper function for tmpfs_readdir.  Creates a '..' entry for the given
  642  * directory and returns it in the uio space.  The function returns 0
  643  * on success, -1 if there was not enough space in the uio structure to
  644  * hold the directory entry or an appropriate error code if another
  645  * error happens.
  646  */
  647 int
  648 tmpfs_dir_getdotdotdent(struct tmpfs_node *node, struct uio *uio)
  649 {
  650         int error;
  651         struct dirent dent;
  652 
  653         TMPFS_VALIDATE_DIR(node);
  654         MPASS(uio->uio_offset == TMPFS_DIRCOOKIE_DOTDOT);
  655 
  656         dent.d_fileno = node->tn_dir.tn_parent->tn_id;
  657         dent.d_type = DT_DIR;
  658         dent.d_namlen = 2;
  659         dent.d_name[0] = '.';
  660         dent.d_name[1] = '.';
  661         dent.d_name[2] = '\0';
  662         dent.d_reclen = GENERIC_DIRSIZ(&dent);
  663 
  664         if (dent.d_reclen > uio->uio_resid)
  665                 error = -1;
  666         else {
  667                 error = uiomove(&dent, dent.d_reclen, uio);
  668                 if (error == 0) {
  669                         struct tmpfs_dirent *de;
  670 
  671                         de = TAILQ_FIRST(&node->tn_dir.tn_dirhead);
  672                         if (de == NULL)
  673                                 uio->uio_offset = TMPFS_DIRCOOKIE_EOF;
  674                         else
  675                                 uio->uio_offset = tmpfs_dircookie(de);
  676                 }
  677         }
  678 
  679         node->tn_status |= TMPFS_NODE_ACCESSED;
  680 
  681         return error;
  682 }
  683 
  684 /* --------------------------------------------------------------------- */
  685 
  686 /*
  687  * Lookup a directory entry by its associated cookie.
  688  */
  689 struct tmpfs_dirent *
  690 tmpfs_dir_lookupbycookie(struct tmpfs_node *node, off_t cookie)
  691 {
  692         struct tmpfs_dirent *de;
  693 
  694         if (cookie == node->tn_dir.tn_readdir_lastn &&
  695             node->tn_dir.tn_readdir_lastp != NULL) {
  696                 return node->tn_dir.tn_readdir_lastp;
  697         }
  698 
  699         TAILQ_FOREACH(de, &node->tn_dir.tn_dirhead, td_entries) {
  700                 if (tmpfs_dircookie(de) == cookie) {
  701                         break;
  702                 }
  703         }
  704 
  705         return de;
  706 }
  707 
  708 /* --------------------------------------------------------------------- */
  709 
  710 /*
  711  * Helper function for tmpfs_readdir.  Returns as much directory entries
  712  * as can fit in the uio space.  The read starts at uio->uio_offset.
  713  * The function returns 0 on success, -1 if there was not enough space
  714  * in the uio structure to hold the directory entry or an appropriate
  715  * error code if another error happens.
  716  */
  717 int
  718 tmpfs_dir_getdents(struct tmpfs_node *node, struct uio *uio, off_t *cntp)
  719 {
  720         int error;
  721         off_t startcookie;
  722         struct tmpfs_dirent *de;
  723 
  724         TMPFS_VALIDATE_DIR(node);
  725 
  726         /* Locate the first directory entry we have to return.  We have cached
  727          * the last readdir in the node, so use those values if appropriate.
  728          * Otherwise do a linear scan to find the requested entry. */
  729         startcookie = uio->uio_offset;
  730         MPASS(startcookie != TMPFS_DIRCOOKIE_DOT);
  731         MPASS(startcookie != TMPFS_DIRCOOKIE_DOTDOT);
  732         if (startcookie == TMPFS_DIRCOOKIE_EOF) {
  733                 return 0;
  734         } else {
  735                 de = tmpfs_dir_lookupbycookie(node, startcookie);
  736         }
  737         if (de == NULL) {
  738                 return EINVAL;
  739         }
  740 
  741         /* Read as much entries as possible; i.e., until we reach the end of
  742          * the directory or we exhaust uio space. */
  743         do {
  744                 struct dirent d;
  745 
  746                 /* Create a dirent structure representing the current
  747                  * tmpfs_node and fill it. */
  748                 d.d_fileno = de->td_node->tn_id;
  749                 switch (de->td_node->tn_type) {
  750                 case VBLK:
  751                         d.d_type = DT_BLK;
  752                         break;
  753 
  754                 case VCHR:
  755                         d.d_type = DT_CHR;
  756                         break;
  757 
  758                 case VDIR:
  759                         d.d_type = DT_DIR;
  760                         break;
  761 
  762                 case VFIFO:
  763                         d.d_type = DT_FIFO;
  764                         break;
  765 
  766                 case VLNK:
  767                         d.d_type = DT_LNK;
  768                         break;
  769 
  770                 case VREG:
  771                         d.d_type = DT_REG;
  772                         break;
  773 
  774                 case VSOCK:
  775                         d.d_type = DT_SOCK;
  776                         break;
  777 
  778                 default:
  779                         panic("tmpfs_dir_getdents: type %p %d",
  780                             de->td_node, (int)de->td_node->tn_type);
  781                 }
  782                 d.d_namlen = de->td_namelen;
  783                 MPASS(de->td_namelen < sizeof(d.d_name));
  784                 (void)memcpy(d.d_name, de->td_name, de->td_namelen);
  785                 d.d_name[de->td_namelen] = '\0';
  786                 d.d_reclen = GENERIC_DIRSIZ(&d);
  787 
  788                 /* Stop reading if the directory entry we are treating is
  789                  * bigger than the amount of data that can be returned. */
  790                 if (d.d_reclen > uio->uio_resid) {
  791                         error = -1;
  792                         break;
  793                 }
  794 
  795                 /* Copy the new dirent structure into the output buffer and
  796                  * advance pointers. */
  797                 error = uiomove(&d, d.d_reclen, uio);
  798 
  799                 (*cntp)++;
  800                 de = TAILQ_NEXT(de, td_entries);
  801         } while (error == 0 && uio->uio_resid > 0 && de != NULL);
  802 
  803         /* Update the offset and cache. */
  804         if (de == NULL) {
  805                 uio->uio_offset = TMPFS_DIRCOOKIE_EOF;
  806                 node->tn_dir.tn_readdir_lastn = 0;
  807                 node->tn_dir.tn_readdir_lastp = NULL;
  808         } else {
  809                 node->tn_dir.tn_readdir_lastn = uio->uio_offset = tmpfs_dircookie(de);
  810                 node->tn_dir.tn_readdir_lastp = de;
  811         }
  812 
  813         node->tn_status |= TMPFS_NODE_ACCESSED;
  814         return error;
  815 }
  816 
  817 /* --------------------------------------------------------------------- */
  818 
  819 /*
  820  * Resizes the aobj associated to the regular file pointed to by vp to
  821  * the size newsize.  'vp' must point to a vnode that represents a regular
  822  * file.  'newsize' must be positive.
  823  *
  824  * Returns zero on success or an appropriate error code on failure.
  825  */
  826 int
  827 tmpfs_reg_resize(struct vnode *vp, off_t newsize)
  828 {
  829         int error;
  830         size_t newpages, oldpages;
  831         struct tmpfs_mount *tmp;
  832         struct tmpfs_node *node;
  833         off_t oldsize;
  834 
  835         MPASS(vp->v_type == VREG);
  836         MPASS(newsize >= 0);
  837 
  838         node = VP_TO_TMPFS_NODE(vp);
  839         tmp = VFS_TO_TMPFS(vp->v_mount);
  840 
  841         /* Convert the old and new sizes to the number of pages needed to
  842          * store them.  It may happen that we do not need to do anything
  843          * because the last allocated page can accommodate the change on
  844          * its own. */
  845         oldsize = node->tn_size;
  846         oldpages = round_page(oldsize) / PAGE_SIZE;
  847         MPASS(oldpages == node->tn_reg.tn_aobj_pages);
  848         newpages = round_page(newsize) / PAGE_SIZE;
  849 
  850         if (newpages > oldpages &&
  851             newpages - oldpages > TMPFS_PAGES_AVAIL(tmp)) {
  852                 error = ENOSPC;
  853                 goto out;
  854         }
  855 
  856         node->tn_reg.tn_aobj_pages = newpages;
  857 
  858         TMPFS_LOCK(tmp);
  859         tmp->tm_pages_used += (newpages - oldpages);
  860         TMPFS_UNLOCK(tmp);
  861 
  862         node->tn_size = newsize;
  863         vnode_pager_setsize(vp, newsize);
  864         if (newsize < oldsize) {
  865                 size_t zerolen = round_page(newsize) - newsize;
  866                 vm_object_t uobj = node->tn_reg.tn_aobj;
  867                 vm_page_t m;
  868 
  869                 /*
  870                  * free "backing store"
  871                  */
  872                 VM_OBJECT_LOCK(uobj);
  873                 if (newpages < oldpages) {
  874                         swap_pager_freespace(uobj,
  875                                                 newpages, oldpages - newpages);
  876                         vm_object_page_remove(uobj,
  877                                 OFF_TO_IDX(newsize + PAGE_MASK), 0, FALSE);
  878                 }
  879 
  880                 /*
  881                  * zero out the truncated part of the last page.
  882                  */
  883 
  884                 if (zerolen > 0) {
  885                         m = vm_page_grab(uobj, OFF_TO_IDX(newsize),
  886                                         VM_ALLOC_NORMAL | VM_ALLOC_RETRY);
  887                         pmap_zero_page_area(m, PAGE_SIZE - zerolen,
  888                                 zerolen);
  889                         vm_page_wakeup(m);
  890                 }
  891                 VM_OBJECT_UNLOCK(uobj);
  892 
  893         }
  894 
  895         error = 0;
  896 
  897 out:
  898         return error;
  899 }
  900 
  901 /* --------------------------------------------------------------------- */
  902 
  903 /*
  904  * Change flags of the given vnode.
  905  * Caller should execute tmpfs_update on vp after a successful execution.
  906  * The vnode must be locked on entry and remain locked on exit.
  907  */
  908 int
  909 tmpfs_chflags(struct vnode *vp, int flags, struct ucred *cred, struct thread *p)
  910 {
  911         int error;
  912         struct tmpfs_node *node;
  913 
  914         MPASS(VOP_ISLOCKED(vp));
  915 
  916         node = VP_TO_TMPFS_NODE(vp);
  917 
  918         /* Disallow this operation if the file system is mounted read-only. */
  919         if (vp->v_mount->mnt_flag & MNT_RDONLY)
  920                 return EROFS;
  921 
  922         /*
  923          * Callers may only modify the file flags on objects they
  924          * have VADMIN rights for.
  925          */
  926         if ((error = VOP_ACCESS(vp, VADMIN, cred, p)))
  927                 return (error);
  928         /*
  929          * Unprivileged processes are not permitted to unset system
  930          * flags, or modify flags if any system flags are set.
  931          */
  932         if (!priv_check_cred(cred, PRIV_VFS_SYSFLAGS, 0)) {
  933                 if (node->tn_flags
  934                   & (SF_NOUNLINK | SF_IMMUTABLE | SF_APPEND)) {
  935                         error = securelevel_gt(cred, 0);
  936                         if (error)
  937                                 return (error);
  938                 }
  939                 /* Snapshot flag cannot be set or cleared */
  940                 if (((flags & SF_SNAPSHOT) != 0 &&
  941                   (node->tn_flags & SF_SNAPSHOT) == 0) ||
  942                   ((flags & SF_SNAPSHOT) == 0 &&
  943                   (node->tn_flags & SF_SNAPSHOT) != 0))
  944                         return (EPERM);
  945                 node->tn_flags = flags;
  946         } else {
  947                 if (node->tn_flags
  948                   & (SF_NOUNLINK | SF_IMMUTABLE | SF_APPEND) ||
  949                   (flags & UF_SETTABLE) != flags)
  950                         return (EPERM);
  951                 node->tn_flags &= SF_SETTABLE;
  952                 node->tn_flags |= (flags & UF_SETTABLE);
  953         }
  954         node->tn_status |= TMPFS_NODE_CHANGED;
  955 
  956         MPASS(VOP_ISLOCKED(vp));
  957 
  958         return 0;
  959 }
  960 
  961 /* --------------------------------------------------------------------- */
  962 
  963 /*
  964  * Change access mode on the given vnode.
  965  * Caller should execute tmpfs_update on vp after a successful execution.
  966  * The vnode must be locked on entry and remain locked on exit.
  967  */
  968 int
  969 tmpfs_chmod(struct vnode *vp, mode_t mode, struct ucred *cred, struct thread *p)
  970 {
  971         int error;
  972         struct tmpfs_node *node;
  973 
  974         MPASS(VOP_ISLOCKED(vp));
  975 
  976         node = VP_TO_TMPFS_NODE(vp);
  977 
  978         /* Disallow this operation if the file system is mounted read-only. */
  979         if (vp->v_mount->mnt_flag & MNT_RDONLY)
  980                 return EROFS;
  981 
  982         /* Immutable or append-only files cannot be modified, either. */
  983         if (node->tn_flags & (IMMUTABLE | APPEND))
  984                 return EPERM;
  985 
  986         /*
  987          * To modify the permissions on a file, must possess VADMIN
  988          * for that file.
  989          */
  990         if ((error = VOP_ACCESS(vp, VADMIN, cred, p)))
  991                 return (error);
  992 
  993         /*
  994          * Privileged processes may set the sticky bit on non-directories,
  995          * as well as set the setgid bit on a file with a group that the
  996          * process is not a member of.
  997          */
  998         if (vp->v_type != VDIR && (mode & S_ISTXT)) {
  999                 if (priv_check_cred(cred, PRIV_VFS_STICKYFILE, 0))
 1000                         return (EFTYPE);
 1001         }
 1002         if (!groupmember(node->tn_gid, cred) && (mode & S_ISGID)) {
 1003                 error = priv_check_cred(cred, PRIV_VFS_SETGID, 0);
 1004                 if (error)
 1005                         return (error);
 1006         }
 1007 
 1008 
 1009         node->tn_mode &= ~ALLPERMS;
 1010         node->tn_mode |= mode & ALLPERMS;
 1011 
 1012         node->tn_status |= TMPFS_NODE_CHANGED;
 1013 
 1014         MPASS(VOP_ISLOCKED(vp));
 1015 
 1016         return 0;
 1017 }
 1018 
 1019 /* --------------------------------------------------------------------- */
 1020 
 1021 /*
 1022  * Change ownership of the given vnode.  At least one of uid or gid must
 1023  * be different than VNOVAL.  If one is set to that value, the attribute
 1024  * is unchanged.
 1025  * Caller should execute tmpfs_update on vp after a successful execution.
 1026  * The vnode must be locked on entry and remain locked on exit.
 1027  */
 1028 int
 1029 tmpfs_chown(struct vnode *vp, uid_t uid, gid_t gid, struct ucred *cred,
 1030     struct thread *p)
 1031 {
 1032         int error;
 1033         struct tmpfs_node *node;
 1034         uid_t ouid;
 1035         gid_t ogid;
 1036 
 1037         MPASS(VOP_ISLOCKED(vp));
 1038 
 1039         node = VP_TO_TMPFS_NODE(vp);
 1040 
 1041         /* Assign default values if they are unknown. */
 1042         MPASS(uid != VNOVAL || gid != VNOVAL);
 1043         if (uid == VNOVAL)
 1044                 uid = node->tn_uid;
 1045         if (gid == VNOVAL)
 1046                 gid = node->tn_gid;
 1047         MPASS(uid != VNOVAL && gid != VNOVAL);
 1048 
 1049         /* Disallow this operation if the file system is mounted read-only. */
 1050         if (vp->v_mount->mnt_flag & MNT_RDONLY)
 1051                 return EROFS;
 1052 
 1053         /* Immutable or append-only files cannot be modified, either. */
 1054         if (node->tn_flags & (IMMUTABLE | APPEND))
 1055                 return EPERM;
 1056 
 1057         /*
 1058          * To modify the ownership of a file, must possess VADMIN for that
 1059          * file.
 1060          */
 1061         if ((error = VOP_ACCESS(vp, VADMIN, cred, p)))
 1062                 return (error);
 1063 
 1064         /*
 1065          * To change the owner of a file, or change the group of a file to a
 1066          * group of which we are not a member, the caller must have
 1067          * privilege.
 1068          */
 1069         if ((uid != node->tn_uid ||
 1070             (gid != node->tn_gid && !groupmember(gid, cred))) &&
 1071             (error = priv_check_cred(cred, PRIV_VFS_CHOWN, 0)))
 1072                 return (error);
 1073 
 1074         ogid = node->tn_gid;
 1075         ouid = node->tn_uid;
 1076 
 1077         node->tn_uid = uid;
 1078         node->tn_gid = gid;
 1079 
 1080         node->tn_status |= TMPFS_NODE_CHANGED;
 1081 
 1082         if ((node->tn_mode & (S_ISUID | S_ISGID)) && (ouid != uid || ogid != gid)) {
 1083                 if (priv_check_cred(cred, PRIV_VFS_RETAINSUGID, 0))
 1084                         node->tn_mode &= ~(S_ISUID | S_ISGID);
 1085         }
 1086 
 1087         MPASS(VOP_ISLOCKED(vp));
 1088 
 1089         return 0;
 1090 }
 1091 
 1092 /* --------------------------------------------------------------------- */
 1093 
 1094 /*
 1095  * Change size of the given vnode.
 1096  * Caller should execute tmpfs_update on vp after a successful execution.
 1097  * The vnode must be locked on entry and remain locked on exit.
 1098  */
 1099 int
 1100 tmpfs_chsize(struct vnode *vp, u_quad_t size, struct ucred *cred,
 1101     struct thread *p)
 1102 {
 1103         int error;
 1104         struct tmpfs_node *node;
 1105 
 1106         MPASS(VOP_ISLOCKED(vp));
 1107 
 1108         node = VP_TO_TMPFS_NODE(vp);
 1109 
 1110         /* Decide whether this is a valid operation based on the file type. */
 1111         error = 0;
 1112         switch (vp->v_type) {
 1113         case VDIR:
 1114                 return EISDIR;
 1115 
 1116         case VREG:
 1117                 if (vp->v_mount->mnt_flag & MNT_RDONLY)
 1118                         return EROFS;
 1119                 break;
 1120 
 1121         case VBLK:
 1122                 /* FALLTHROUGH */
 1123         case VCHR:
 1124                 /* FALLTHROUGH */
 1125         case VFIFO:
 1126                 /* Allow modifications of special files even if in the file
 1127                  * system is mounted read-only (we are not modifying the
 1128                  * files themselves, but the objects they represent). */
 1129                 return 0;
 1130 
 1131         default:
 1132                 /* Anything else is unsupported. */
 1133                 return EOPNOTSUPP;
 1134         }
 1135 
 1136         /* Immutable or append-only files cannot be modified, either. */
 1137         if (node->tn_flags & (IMMUTABLE | APPEND))
 1138                 return EPERM;
 1139 
 1140         error = tmpfs_truncate(vp, size);
 1141         /* tmpfs_truncate will raise the NOTE_EXTEND and NOTE_ATTRIB kevents
 1142          * for us, as will update tn_status; no need to do that here. */
 1143 
 1144         MPASS(VOP_ISLOCKED(vp));
 1145 
 1146         return error;
 1147 }
 1148 
 1149 /* --------------------------------------------------------------------- */
 1150 
 1151 /*
 1152  * Change access and modification times of the given vnode.
 1153  * Caller should execute tmpfs_update on vp after a successful execution.
 1154  * The vnode must be locked on entry and remain locked on exit.
 1155  */
 1156 int
 1157 tmpfs_chtimes(struct vnode *vp, struct timespec *atime, struct timespec *mtime,
 1158         struct timespec *birthtime, int vaflags, struct ucred *cred, struct thread *l)
 1159 {
 1160         int error;
 1161         struct tmpfs_node *node;
 1162 
 1163         MPASS(VOP_ISLOCKED(vp));
 1164 
 1165         node = VP_TO_TMPFS_NODE(vp);
 1166 
 1167         /* Disallow this operation if the file system is mounted read-only. */
 1168         if (vp->v_mount->mnt_flag & MNT_RDONLY)
 1169                 return EROFS;
 1170 
 1171         /* Immutable or append-only files cannot be modified, either. */
 1172         if (node->tn_flags & (IMMUTABLE | APPEND))
 1173                 return EPERM;
 1174 
 1175         /* Determine if the user have proper privilege to update time. */
 1176         if (vaflags & VA_UTIMES_NULL) {
 1177                 error = VOP_ACCESS(vp, VADMIN, cred, l);
 1178                 if (error)
 1179                         error = VOP_ACCESS(vp, VWRITE, cred, l);
 1180         } else
 1181                 error = VOP_ACCESS(vp, VADMIN, cred, l);
 1182         if (error)
 1183                 return (error);
 1184 
 1185         if (atime->tv_sec != VNOVAL && atime->tv_nsec != VNOVAL)
 1186                 node->tn_status |= TMPFS_NODE_ACCESSED;
 1187 
 1188         if (mtime->tv_sec != VNOVAL && mtime->tv_nsec != VNOVAL)
 1189                 node->tn_status |= TMPFS_NODE_MODIFIED;
 1190 
 1191         if (birthtime->tv_nsec != VNOVAL && birthtime->tv_nsec != VNOVAL)
 1192                 node->tn_status |= TMPFS_NODE_MODIFIED;
 1193 
 1194         tmpfs_itimes(vp, atime, mtime);
 1195 
 1196         if (birthtime->tv_nsec != VNOVAL && birthtime->tv_nsec != VNOVAL)
 1197                 node->tn_birthtime = *birthtime;
 1198         MPASS(VOP_ISLOCKED(vp));
 1199 
 1200         return 0;
 1201 }
 1202 
 1203 /* --------------------------------------------------------------------- */
 1204 /* Sync timestamps */
 1205 void
 1206 tmpfs_itimes(struct vnode *vp, const struct timespec *acc,
 1207     const struct timespec *mod)
 1208 {
 1209         struct tmpfs_node *node;
 1210         struct timespec now;
 1211 
 1212         node = VP_TO_TMPFS_NODE(vp);
 1213 
 1214         if ((node->tn_status & (TMPFS_NODE_ACCESSED | TMPFS_NODE_MODIFIED |
 1215             TMPFS_NODE_CHANGED)) == 0)
 1216                 return;
 1217 
 1218         vfs_timestamp(&now);
 1219         if (node->tn_status & TMPFS_NODE_ACCESSED) {
 1220                 if (acc == NULL)
 1221                          acc = &now;
 1222                 node->tn_atime = *acc;
 1223         }
 1224         if (node->tn_status & TMPFS_NODE_MODIFIED) {
 1225                 if (mod == NULL)
 1226                         mod = &now;
 1227                 node->tn_mtime = *mod;
 1228         }
 1229         if (node->tn_status & TMPFS_NODE_CHANGED) {
 1230                 node->tn_ctime = now;
 1231         }
 1232         node->tn_status &=
 1233             ~(TMPFS_NODE_ACCESSED | TMPFS_NODE_MODIFIED | TMPFS_NODE_CHANGED);
 1234 }
 1235 
 1236 /* --------------------------------------------------------------------- */
 1237 
 1238 void
 1239 tmpfs_update(struct vnode *vp)
 1240 {
 1241 
 1242         tmpfs_itimes(vp, NULL, NULL);
 1243 }
 1244 
 1245 /* --------------------------------------------------------------------- */
 1246 
 1247 int
 1248 tmpfs_truncate(struct vnode *vp, off_t length)
 1249 {
 1250         int error;
 1251         struct tmpfs_node *node;
 1252 
 1253         node = VP_TO_TMPFS_NODE(vp);
 1254 
 1255         if (length < 0) {
 1256                 error = EINVAL;
 1257                 goto out;
 1258         }
 1259 
 1260         if (node->tn_size == length) {
 1261                 error = 0;
 1262                 goto out;
 1263         }
 1264 
 1265         if (length > VFS_TO_TMPFS(vp->v_mount)->tm_maxfilesize)
 1266                 return (EFBIG);
 1267 
 1268         error = tmpfs_reg_resize(vp, length);
 1269         if (error == 0) {
 1270                 node->tn_status |= TMPFS_NODE_CHANGED | TMPFS_NODE_MODIFIED;
 1271         }
 1272 
 1273 out:
 1274         tmpfs_update(vp);
 1275 
 1276         return error;
 1277 }
Cache object: 96551f8b0c5fc77694327cf8be33cdb9
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FreeBSD/Linux Kernel Cross Reference sys/fs/tmpfs/tmpfs_subr.c

FreeBSD/Linux Kernel Cross Reference
sys/fs/tmpfs/tmpfs_subr.c
