FreeBSD/Linux Kernel Cross Reference
sys/fs/fuse/fuse_node.c

     /*-
      * SPDX-License-Identifier: BSD-3-Clause
      *
      * Copyright (c) 2007-2009 Google Inc. and Amit Singh
      * All rights reserved.
      *
      * Redistribution and use in source and binary forms, with or without
      * modification, are permitted provided that the following conditions are
      * met:
     *
     * * Redistributions of source code must retain the above copyright
     *   notice, this list of conditions and the following disclaimer.
     * * Redistributions in binary form must reproduce the above
     *   copyright notice, this list of conditions and the following disclaimer
     *   in the documentation and/or other materials provided with the
     *   distribution.
     * * Neither the name of Google Inc. nor the names of its
     *   contributors may be used to endorse or promote products derived from
     *   this software without specific prior written permission.
     *
     * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
     * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
     * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
     * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     *
     * Copyright (C) 2005 Csaba Henk.
     * All rights reserved.
     *
     * Copyright (c) 2019 The FreeBSD Foundation
     *
     * Portions of this software were developed by BFF Storage Systems, LLC under
     * sponsorship from the FreeBSD Foundation.
     *
     * Redistribution and use in source and binary forms, with or without
     * modification, are permitted provided that the following conditions
     * are met:
     * 1. Redistributions of source code must retain the above copyright
     *    notice, this list of conditions and the following disclaimer.
     * 2. Redistributions in binary form must reproduce the above copyright
     *    notice, this list of conditions and the following disclaimer in the
     *    documentation and/or other materials provided with the distribution.
     *
     * THIS SOFTWARE IS PROVIDED BY AUTHOR AND CONTRIBUTORS ``AS IS'' AND
     * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     * ARE DISCLAIMED.  IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE
     * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     * SUCH DAMAGE.
     */
    
    #include <sys/cdefs.h>
    __FBSDID("$FreeBSD$");
    
    #include <sys/types.h>
    #include <sys/systm.h>
    #include <sys/counter.h>
    #include <sys/module.h>
    #include <sys/errno.h>
    #include <sys/param.h>
    #include <sys/kernel.h>
    #include <sys/conf.h>
    #include <sys/uio.h>
    #include <sys/malloc.h>
    #include <sys/queue.h>
    #include <sys/lock.h>
    #include <sys/sx.h>
    #include <sys/mutex.h>
    #include <sys/proc.h>
    #include <sys/vnode.h>
    #include <sys/namei.h>
    #include <sys/mount.h>
    #include <sys/sysctl.h>
    #include <sys/fcntl.h>
    #include <sys/priv.h>
    #include <sys/buf.h>
    #include <security/mac/mac_framework.h>
    #include <vm/vm.h>
    #include <vm/vm_extern.h>
    
    #include "fuse.h"
    #include "fuse_node.h"
    #include "fuse_internal.h"
    #include "fuse_io.h"
    #include "fuse_ipc.h"
    
    SDT_PROVIDER_DECLARE(fusefs);
    /* 
    * Fuse trace probe:
    * arg0: verbosity.  Higher numbers give more verbose messages
    * arg1: Textual message
    */
   SDT_PROBE_DEFINE2(fusefs, , node, trace, "int", "char*");
   
   MALLOC_DEFINE(M_FUSEVN, "fuse_vnode", "fuse vnode private data");
   
   static int sysctl_fuse_cache_mode(SYSCTL_HANDLER_ARGS);
   
   static counter_u64_t fuse_node_count;
   
   SYSCTL_COUNTER_U64(_vfs_fusefs_stats, OID_AUTO, node_count, CTLFLAG_RD,
       &fuse_node_count, "Count of FUSE vnodes");
   
   int     fuse_data_cache_mode = FUSE_CACHE_WT;
   
   /*
    * DEPRECATED
    * This sysctl is no longer needed as of fuse protocol 7.23.  Individual
    * servers can select the cache behavior they need for each mountpoint:
    * - writethrough: the default
    * - writeback: set FUSE_WRITEBACK_CACHE in fuse_init_out.flags
    * - uncached: set FOPEN_DIRECT_IO for every file
    * The sysctl is retained primarily for use by jails supporting older FUSE
    * protocols.  It may be removed entirely once FreeBSD 11.3 and 12.0 are EOL.
    */
   SYSCTL_PROC(_vfs_fusefs, OID_AUTO, data_cache_mode,
       CTLTYPE_INT | CTLFLAG_MPSAFE | CTLFLAG_RW,
       &fuse_data_cache_mode, 0, sysctl_fuse_cache_mode, "I",
       "Zero: disable caching of FUSE file data; One: write-through caching "
       "(default); Two: write-back caching (generally unsafe)");
   
   static int
   sysctl_fuse_cache_mode(SYSCTL_HANDLER_ARGS)
   {
           int val, error;
   
           val = *(int *)arg1;
           error = sysctl_handle_int(oidp, &val, 0, req);
           if (error || !req->newptr)
                   return (error);
   
           switch (val) {
           case FUSE_CACHE_UC:
           case FUSE_CACHE_WT:
           case FUSE_CACHE_WB:
                   *(int *)arg1 = val;
                   break;
           default:
                   return (EDOM);
           }
           return (0);
   }
   
   static void
   fuse_vnode_init(struct vnode *vp, struct fuse_vnode_data *fvdat,
       uint64_t nodeid, enum vtype vtyp)
   {
           fvdat->nid = nodeid;
           LIST_INIT(&fvdat->handles);
           vattr_null(&fvdat->cached_attrs);
           if (nodeid == FUSE_ROOT_ID) {
                   vp->v_vflag |= VV_ROOT;
           }
           vp->v_type = vtyp;
           vp->v_data = fvdat;
           cluster_init_vn(&fvdat->clusterw);
           timespecclear(&fvdat->last_local_modify);
   
           counter_u64_add(fuse_node_count, 1);
   }
   
   void
   fuse_vnode_destroy(struct vnode *vp)
   {
           struct fuse_vnode_data *fvdat = vp->v_data;
   
           vp->v_data = NULL;
           KASSERT(LIST_EMPTY(&fvdat->handles),
                   ("Destroying fuse vnode with open files!"));
           free(fvdat, M_FUSEVN);
   
           counter_u64_add(fuse_node_count, -1);
   }
   
   int
   fuse_vnode_cmp(struct vnode *vp, void *nidp)
   {
           return (VTOI(vp) != *((uint64_t *)nidp));
   }
   
   SDT_PROBE_DEFINE3(fusefs, , node, stale_vnode, "struct vnode*", "enum vtype",
                   "uint64_t");
   static int
   fuse_vnode_alloc(struct mount *mp,
       struct thread *td,
       uint64_t nodeid,
       enum vtype vtyp,
       struct vnode **vpp)
   {
           struct fuse_data *data;
           struct fuse_vnode_data *fvdat;
           struct vnode *vp2;
           int err = 0;
   
           data = fuse_get_mpdata(mp);
           if (vtyp == VNON) {
                   return EINVAL;
           }
           *vpp = NULL;
           err = vfs_hash_get(mp, fuse_vnode_hash(nodeid), LK_EXCLUSIVE, td, vpp,
               fuse_vnode_cmp, &nodeid);
           if (err)
                   return (err);
   
           if (*vpp) {
                   if ((*vpp)->v_type == vtyp) {
                           /* Reuse a vnode that hasn't yet been reclaimed */
                           MPASS((*vpp)->v_data != NULL);
                           MPASS(VTOFUD(*vpp)->nid == nodeid);
                           SDT_PROBE2(fusefs, , node, trace, 1,
                                   "vnode taken from hash");
                           return (0);
                   } else {
                           /*
                            * The inode changed types!  If we get here, we can't
                            * tell whether the inode's entry cache had expired
                            * yet.  So this could be the result of a buggy server,
                            * but more likely the server just reused an inode
                            * number following an entry cache expiration.
                            */
                           SDT_PROBE3(fusefs, , node, stale_vnode, *vpp, vtyp,
                                   nodeid);
                           fuse_internal_vnode_disappear(*vpp);
                           vgone(*vpp);
                           lockmgr((*vpp)->v_vnlock, LK_RELEASE, NULL);
                   }
           }
           fvdat = malloc(sizeof(*fvdat), M_FUSEVN, M_WAITOK | M_ZERO);
           switch (vtyp) {
           case VFIFO:
                   err = getnewvnode("fuse", mp, &fuse_fifoops, vpp);
                   break;
           default:
                   err = getnewvnode("fuse", mp, &fuse_vnops, vpp);
                   break;
           }
           if (err) {
                   free(fvdat, M_FUSEVN);
                   return (err);
           }
           lockmgr((*vpp)->v_vnlock, LK_EXCLUSIVE, NULL);
           fuse_vnode_init(*vpp, fvdat, nodeid, vtyp);
           err = insmntque(*vpp, mp);
           ASSERT_VOP_ELOCKED(*vpp, "fuse_vnode_alloc");
           if (err) {
                   lockmgr((*vpp)->v_vnlock, LK_RELEASE, NULL);
                   free(fvdat, M_FUSEVN);
                   *vpp = NULL;
                   return (err);
           }
           /* Disallow async reads for fifos because UFS does.  I don't know why */
           if (data->dataflags & FSESS_ASYNC_READ && vtyp != VFIFO)
                   VN_LOCK_ASHARE(*vpp);
   
           vn_set_state(*vpp, VSTATE_CONSTRUCTED);
           err = vfs_hash_insert(*vpp, fuse_vnode_hash(nodeid), LK_EXCLUSIVE,
               td, &vp2, fuse_vnode_cmp, &nodeid);
           if (err) {
                   lockmgr((*vpp)->v_vnlock, LK_RELEASE, NULL);
                   free(fvdat, M_FUSEVN);
                   *vpp = NULL;
                   return (err);
           }
           if (vp2 != NULL) {
                   *vpp = vp2;
                   return (0);
           }
   
           ASSERT_VOP_ELOCKED(*vpp, "fuse_vnode_alloc");
   
           return (0);
   }
   
   int
   fuse_vnode_get(struct mount *mp,
       struct fuse_entry_out *feo,
       uint64_t nodeid,
       struct vnode *dvp,
       struct vnode **vpp,
       struct componentname *cnp,
       enum vtype vtyp)
   {
           struct thread *td = curthread;
           /* 
            * feo should only be NULL for the root directory, which (when libfuse
            * is used) always has generation 0
            */
           uint64_t generation = feo ? feo->generation : 0;
           int err = 0;
   
           if (dvp != NULL && VTOFUD(dvp)->nid == nodeid) {
                   fuse_warn(fuse_get_mpdata(mp), FSESS_WARN_ILLEGAL_INODE,
                           "Assigned same inode to both parent and child.");
                   return EIO;
           }
   
           err = fuse_vnode_alloc(mp, td, nodeid, vtyp, vpp);
           if (err) {
                   return err;
           }
           if (dvp != NULL) {
                   MPASS(cnp && (cnp->cn_flags & ISDOTDOT) == 0);
                   MPASS(cnp &&
                           !(cnp->cn_namelen == 1 && cnp->cn_nameptr[0] == '.'));
                   fuse_vnode_setparent(*vpp, dvp);
           }
           if (dvp != NULL && cnp != NULL && (cnp->cn_flags & MAKEENTRY) != 0 &&
               feo != NULL &&
               (feo->entry_valid != 0 || feo->entry_valid_nsec != 0)) {
                   struct timespec timeout;
   
                   ASSERT_VOP_LOCKED(*vpp, "fuse_vnode_get");
                   ASSERT_VOP_LOCKED(dvp, "fuse_vnode_get");
   
                   fuse_validity_2_timespec(feo, &timeout);
                   cache_enter_time(dvp, *vpp, cnp, &timeout, NULL);
           }
   
           VTOFUD(*vpp)->generation = generation;
           /*
            * In userland, libfuse uses cached lookups for dot and dotdot entries,
            * thus it does not really bump the nlookup counter for forget.
            * Follow the same semantic and avoid the bump in order to keep
            * nlookup counters consistent.
            */
           if (cnp == NULL || ((cnp->cn_flags & ISDOTDOT) == 0 &&
               (cnp->cn_namelen != 1 || cnp->cn_nameptr[0] != '.')))
                   VTOFUD(*vpp)->nlookup++;
   
           return 0;
   }
   
   /*
    * Called for every fusefs vnode open to initialize the vnode (not
    * fuse_filehandle) for use
    */
   void
   fuse_vnode_open(struct vnode *vp, int32_t fuse_open_flags, struct thread *td)
   {
           if (vnode_vtype(vp) == VREG)
                   vnode_create_vobject(vp, 0, td);
   }
   
   int
   fuse_vnode_savesize(struct vnode *vp, struct ucred *cred, pid_t pid)
   {
           struct fuse_vnode_data *fvdat = VTOFUD(vp);
           struct thread *td = curthread;
           struct fuse_filehandle *fufh = NULL;
           struct fuse_dispatcher fdi;
           struct fuse_setattr_in *fsai;
           int err = 0;
   
           ASSERT_VOP_ELOCKED(vp, "fuse_io_extend");
   
           if (fuse_isdeadfs(vp)) {
                   return EBADF;
           }
           if (vnode_vtype(vp) == VDIR) {
                   return EISDIR;
           }
           if (vfs_isrdonly(vnode_mount(vp))) {
                   return EROFS;
           }
           if (cred == NULL) {
                   cred = td->td_ucred;
           }
           fdisp_init(&fdi, sizeof(*fsai));
           fdisp_make_vp(&fdi, FUSE_SETATTR, vp, td, cred);
           fsai = fdi.indata;
           fsai->valid = 0;
   
           /* Truncate to a new value. */
           MPASS((fvdat->flag & FN_SIZECHANGE) != 0);
           fsai->size = fvdat->cached_attrs.va_size;
           fsai->valid |= FATTR_SIZE;
   
           fuse_filehandle_getrw(vp, FWRITE, &fufh, cred, pid);
           if (fufh) {
                   fsai->fh = fufh->fh_id;
                   fsai->valid |= FATTR_FH;
           }
           err = fdisp_wait_answ(&fdi);
           fdisp_destroy(&fdi);
           if (err == 0) {
                   getnanouptime(&fvdat->last_local_modify);
                   fvdat->flag &= ~FN_SIZECHANGE;
           }
   
           return err;
   }
   
   /*
    * Adjust the vnode's size to a new value.
    *
    * If the new value came from the server, such as from a FUSE_GETATTR
    * operation, set `from_server` true.  But if it came from a local operation,
    * such as write(2) or truncate(2), set `from_server` false.
    */
   int
   fuse_vnode_setsize(struct vnode *vp, off_t newsize, bool from_server)
   {
           struct fuse_vnode_data *fvdat = VTOFUD(vp);
           struct vattr *attrs;
           off_t oldsize;
           size_t iosize;
           struct buf *bp = NULL;
           int err = 0;
   
           ASSERT_VOP_ELOCKED(vp, "fuse_vnode_setsize");
   
           iosize = fuse_iosize(vp);
           oldsize = fvdat->cached_attrs.va_size;
           fvdat->cached_attrs.va_size = newsize;
           if ((attrs = VTOVA(vp)) != NULL)
                   attrs->va_size = newsize;
   
           if (newsize < oldsize) {
                   daddr_t lbn;
   
                   err = vtruncbuf(vp, newsize, fuse_iosize(vp));
                   if (err)
                           goto out;
                   if (newsize % iosize == 0)
                           goto out;
                   /* 
                    * Zero the contents of the last partial block.
                    * Sure seems like vtruncbuf should do this for us.
                    */
   
                   lbn = newsize / iosize;
                   bp = getblk(vp, lbn, iosize, PCATCH, 0, 0);
                   if (!bp) {
                           err = EINTR;
                           goto out;
                   }
                   if (!(bp->b_flags & B_CACHE))
                           goto out;       /* Nothing to do */
                   MPASS(bp->b_flags & B_VMIO);
                   vfs_bio_clrbuf(bp);
                   bp->b_dirtyend = MIN(bp->b_dirtyend, newsize - lbn * iosize);
           } else if (from_server && newsize > oldsize && oldsize != VNOVAL) {
                   /*
                    * The FUSE server changed the file size behind our back.  We
                    * should invalidate the entire cache.
                    */
                   daddr_t end_lbn;
   
                   end_lbn = howmany(newsize, iosize);
                   v_inval_buf_range(vp, 0, end_lbn, iosize);
           }
   out:
           if (bp)
                   brelse(bp);
           vnode_pager_setsize(vp, newsize);
           return err;
   }
   
   /* Get the current, possibly dirty, size of the file */
   int
   fuse_vnode_size(struct vnode *vp, off_t *filesize, struct ucred *cred,
           struct thread *td)
   {
           struct fuse_vnode_data *fvdat = VTOFUD(vp);
           int error = 0;
   
           if (!(fvdat->flag & FN_SIZECHANGE) &&
                   (!fuse_vnode_attr_cache_valid(vp) ||
                     fvdat->cached_attrs.va_size == VNOVAL)) 
                   error = fuse_internal_do_getattr(vp, NULL, cred, td);
   
           if (!error)
                   *filesize = fvdat->cached_attrs.va_size;
   
           return error;
   }
   
   void
   fuse_vnode_undirty_cached_timestamps(struct vnode *vp, bool atime)
   {
           struct fuse_vnode_data *fvdat = VTOFUD(vp);
   
           fvdat->flag &= ~(FN_MTIMECHANGE | FN_CTIMECHANGE);
           if (atime)
                   fvdat->flag &= ~FN_ATIMECHANGE;
   }
   
   /* Update a fuse file's cached timestamps */
   void
   fuse_vnode_update(struct vnode *vp, int flags)
   {
           struct fuse_vnode_data *fvdat = VTOFUD(vp);
           struct mount *mp = vnode_mount(vp);
           struct fuse_data *data = fuse_get_mpdata(mp);
           struct timespec ts;
   
           vfs_timestamp(&ts);
   
           if (data->time_gran > 1)
                   ts.tv_nsec = rounddown(ts.tv_nsec, data->time_gran);
   
           if (mp->mnt_flag & MNT_NOATIME)
                   flags &= ~FN_ATIMECHANGE;
   
           if (flags & FN_ATIMECHANGE)
                   fvdat->cached_attrs.va_atime = ts;
           if (flags & FN_MTIMECHANGE)
                   fvdat->cached_attrs.va_mtime = ts;
           if (flags & FN_CTIMECHANGE)
                   fvdat->cached_attrs.va_ctime = ts;
   
           fvdat->flag |= flags;
   }
   
   void
   fuse_node_init(void)
   {
           fuse_node_count = counter_u64_alloc(M_WAITOK);
   }
   
   void
   fuse_node_destroy(void)
   {
           counter_u64_free(fuse_node_count);
   }

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