FreeBSD/Linux Kernel Cross Reference
sys/geom/geom_vfs.c

     /*-
      * Copyright (c) 2004 Poul-Henning Kamp
      * All rights reserved.
      *
      * 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 THE 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 THE 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/param.h>
    #include <sys/systm.h>
    #include <sys/bio.h>
    #include <sys/kernel.h>
    #include <sys/malloc.h>
    #include <sys/vnode.h>
    #include <sys/mount.h>  /* XXX Temporary for VFS_LOCK_GIANT */
    
    #include <geom/geom.h>
    #include <geom/geom_vfs.h>
    
    /*
     * subroutines for use by filesystems.
     *
     * XXX: should maybe live somewhere else ?
     */
    #include <sys/buf.h>
    
    static struct buf_ops __g_vfs_bufops = {
            .bop_name =     "GEOM_VFS",
            .bop_write =    bufwrite,
            .bop_strategy = g_vfs_strategy, 
            .bop_sync =     bufsync,        
            .bop_bdflush =  bufbdflush
    };
    
    struct buf_ops *g_vfs_bufops = &__g_vfs_bufops;
    
    static g_orphan_t g_vfs_orphan;
    
    static struct g_class g_vfs_class = {
            .name =         "VFS",
            .version =      G_VERSION,
            .orphan =       g_vfs_orphan,
    };
    
    DECLARE_GEOM_CLASS(g_vfs_class, g_vfs);
    
    static void
    g_vfs_done(struct bio *bip)
    {
            struct buf *bp;
            int vfslocked;
    
            /*
             * Provider ('bio_to') could have withered away sometime
             * between incrementing the 'nend' in g_io_deliver() and now,
             * making 'bio_to' a dangling pointer.  We cannot do that
             * in g_wither_geom(), as it would require going over
             * the 'g_bio_run_up' list, resetting the pointer.
             */
            if (bip->bio_from->provider == NULL)
                    bip->bio_to = NULL;
    
            if (bip->bio_error) {
                    printf("g_vfs_done():");
                    g_print_bio(bip);
                    printf("error = %d\n", bip->bio_error);
            }
            bp = bip->bio_caller2;
            bp->b_error = bip->bio_error;
            bp->b_ioflags = bip->bio_flags;
            if (bip->bio_error)
                    bp->b_ioflags |= BIO_ERROR;
            bp->b_resid = bp->b_bcount - bip->bio_completed;
            g_destroy_bio(bip);
            vfslocked = VFS_LOCK_GIANT(((struct mount *)NULL));
            bufdone(bp);
            VFS_UNLOCK_GIANT(vfslocked);
    }
   
   void
   g_vfs_strategy(struct bufobj *bo, struct buf *bp)
   {
           struct g_consumer *cp;
           struct bio *bip;
           int vfslocked;
   
           cp = bo->bo_private;
           /* G_VALID_CONSUMER(cp); We likely lack topology lock */
   
           /*
            * If the provider has orphaned us, just return EXIO.
            */
           if (cp->provider == NULL) {
                   bp->b_error = ENXIO;
                   bp->b_ioflags |= BIO_ERROR;
                   vfslocked = VFS_LOCK_GIANT(((struct mount *)NULL));
                   bufdone(bp);
                   VFS_UNLOCK_GIANT(vfslocked);
                   return;
           }
   
           bip = g_alloc_bio();
           bip->bio_cmd = bp->b_iocmd;
           bip->bio_offset = bp->b_iooffset;
           bip->bio_data = bp->b_data;
           bip->bio_done = g_vfs_done;
           bip->bio_caller2 = bp;
           bip->bio_length = bp->b_bcount;
           if (bp->b_flags & B_BARRIER) {
                   bip->bio_flags |= BIO_ORDERED;
                   bp->b_flags &= ~B_BARRIER;
           }
           g_io_request(bip, cp);
   }
   
   static void
   g_vfs_orphan(struct g_consumer *cp)
   {
           struct g_geom *gp;
           struct bufobj *bo;
   
           g_topology_assert();
   
           gp = cp->geom;
           bo = gp->softc;
           g_trace(G_T_TOPOLOGY, "g_vfs_orphan(%p(%s))", cp, gp->name);
           if (cp->acr > 0 || cp->acw > 0 || cp->ace > 0)
                   g_access(cp, -cp->acr, -cp->acw, -cp->ace);
           g_detach(cp);
   
           /*
            * Do not destroy the geom.  Filesystem will do that during unmount.
            */
   }
   
   int
   g_vfs_open(struct vnode *vp, struct g_consumer **cpp, const char *fsname, int wr)
   {
           struct g_geom *gp;
           struct g_provider *pp;
           struct g_consumer *cp;
           struct bufobj *bo;
           int vfslocked;
           int error;
   
           g_topology_assert();
   
           *cpp = NULL;
           bo = &vp->v_bufobj;
           if (bo->bo_private != vp)
                   return (EBUSY);
   
           pp = g_dev_getprovider(vp->v_rdev);
           if (pp == NULL)
                   return (ENOENT);
           gp = g_new_geomf(&g_vfs_class, "%s.%s", fsname, pp->name);
           cp = g_new_consumer(gp);
           g_attach(cp, pp);
           error = g_access(cp, 1, wr, 1);
           if (error) {
                   g_wither_geom(gp, ENXIO);
                   return (error);
           }
           vfslocked = VFS_LOCK_GIANT(vp->v_mount);
           vnode_create_vobject(vp, pp->mediasize, curthread);
           VFS_UNLOCK_GIANT(vfslocked);
           *cpp = cp;
           cp->private = vp;
           bo->bo_ops = g_vfs_bufops;
           bo->bo_private = cp;
           bo->bo_bsize = pp->sectorsize;
           gp->softc = bo;
   
           return (error);
   }
   
   void
   g_vfs_close(struct g_consumer *cp)
   {
           struct g_geom *gp;
           struct bufobj *bo;
   
           g_topology_assert();
   
           gp = cp->geom;
           bo = gp->softc;
           bufobj_invalbuf(bo, V_SAVE, 0, 0);
           bo->bo_private = cp->private;
           g_wither_geom_close(gp, ENXIO);
   }

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