2cc7d26f7f
file are after snaplock, while other ffs device buffers are before snaplock in global lock order. By itself, this could cause deadlock when bdwrite() tries to flush dirty buffers on snapshotted ffs. If, during the flush, COW activity for snapshot needs to allocate block and ffs_alloccg() selects the cylinder group that is being written by bdwrite(), then kernel would panic due to recursive buffer lock acquision. Avoid dealing with buffers in bdwrite() that are from other side of snaplock divisor in the lock order then the buffer being written. Add new BOP, bop_bdwrite(), to do dirty buffer flushing for same vnode in the bdwrite(). Default implementation, bufbdflush(), refactors the code from bdwrite(). For ffs device buffers, specialized implementation is used. Reviewed by: tegge, jeff, Russell Cattelan (cattelan xfs org, xfs changes) Tested by: Peter Holm X-MFC after: 3 weeks (if ever: it changes ABI)
178 lines
4.5 KiB
C
178 lines
4.5 KiB
C
/*-
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* Copyright (c) 2004 Poul-Henning Kamp
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/bio.h>
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#include <sys/kernel.h>
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#include <sys/malloc.h>
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#include <sys/vnode.h>
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#include <sys/mount.h> /* XXX Temporary for VFS_LOCK_GIANT */
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#include <geom/geom.h>
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#include <geom/geom_vfs.h>
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/*
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* subroutines for use by filesystems.
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*
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* XXX: should maybe live somewhere else ?
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*/
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#include <sys/buf.h>
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static struct buf_ops __g_vfs_bufops = {
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.bop_name = "GEOM_VFS",
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.bop_write = bufwrite,
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.bop_strategy = g_vfs_strategy,
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.bop_sync = bufsync,
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.bop_bdflush = bufbdflush
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};
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struct buf_ops *g_vfs_bufops = &__g_vfs_bufops;
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static g_orphan_t g_vfs_orphan;
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static struct g_class g_vfs_class = {
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.name = "VFS",
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.version = G_VERSION,
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.orphan = g_vfs_orphan,
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};
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DECLARE_GEOM_CLASS(g_vfs_class, g_vfs);
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static void
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g_vfs_done(struct bio *bip)
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{
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struct buf *bp;
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int vfslocked;
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if (bip->bio_error) {
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printf("g_vfs_done():");
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g_print_bio(bip);
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printf("error = %d\n", bip->bio_error);
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}
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bp = bip->bio_caller2;
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bp->b_error = bip->bio_error;
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bp->b_ioflags = bip->bio_flags;
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if (bip->bio_error)
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bp->b_ioflags |= BIO_ERROR;
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bp->b_resid = bp->b_bcount - bip->bio_completed;
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g_destroy_bio(bip);
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vfslocked = VFS_LOCK_GIANT(((struct mount *)NULL));
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bufdone(bp);
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VFS_UNLOCK_GIANT(vfslocked);
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}
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void
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g_vfs_strategy(struct bufobj *bo, struct buf *bp)
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{
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struct g_consumer *cp;
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struct bio *bip;
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cp = bo->bo_private;
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G_VALID_CONSUMER(cp);
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bip = g_alloc_bio();
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bip->bio_cmd = bp->b_iocmd;
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bip->bio_offset = bp->b_iooffset;
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bip->bio_data = bp->b_data;
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bip->bio_done = g_vfs_done;
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bip->bio_caller2 = bp;
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bip->bio_length = bp->b_bcount;
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g_io_request(bip, cp);
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}
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static void
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g_vfs_orphan(struct g_consumer *cp)
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{
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/*
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* Don't do anything here yet.
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*
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* Ideally we should detach the consumer already now, but that
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* leads to a locking requirement in the I/O path to see if we have
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* a consumer or not. Considering how ugly things are going to get
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* anyway as none of our filesystems are graceful about i/o errors,
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* this is not important right now.
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*
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* Down the road, this is the place where we could give the user
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* a "Abort, Retry or Ignore" option to replace the media again.
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*/
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}
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int
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g_vfs_open(struct vnode *vp, struct g_consumer **cpp, const char *fsname, int wr)
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{
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struct g_geom *gp;
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struct g_provider *pp;
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struct g_consumer *cp;
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struct bufobj *bo;
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int vfslocked;
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int error;
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g_topology_assert();
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*cpp = NULL;
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pp = g_dev_getprovider(vp->v_rdev);
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if (pp == NULL)
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return (ENOENT);
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gp = g_new_geomf(&g_vfs_class, "%s.%s", fsname, pp->name);
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cp = g_new_consumer(gp);
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g_attach(cp, pp);
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error = g_access(cp, 1, wr, 1);
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if (error) {
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g_wither_geom(gp, ENXIO);
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return (error);
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}
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vfslocked = VFS_LOCK_GIANT(vp->v_mount);
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vnode_create_vobject(vp, pp->mediasize, curthread);
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VFS_UNLOCK_GIANT(vfslocked);
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*cpp = cp;
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bo = &vp->v_bufobj;
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bo->bo_ops = g_vfs_bufops;
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bo->bo_private = cp;
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bo->bo_bsize = pp->sectorsize;
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gp->softc = bo;
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return (error);
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}
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void
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g_vfs_close(struct g_consumer *cp, struct thread *td)
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{
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struct g_geom *gp;
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struct bufobj *bo;
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g_topology_assert();
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gp = cp->geom;
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bo = gp->softc;
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bufobj_invalbuf(bo, V_SAVE, td, 0, 0);
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g_wither_geom_close(gp, ENXIO);
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}
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