0458054c4e
description:
How it works:
--
Basically ifs is a copy of ffs, overriding some vfs/vnops. (Yes, hack.)
I didn't see the need in duplicating all of sys/ufs/ffs to get this
off the ground.
File creation is done through a special file - 'newfile' . When newfile
is called, the system allocates and returns an inode. Note that newfile
is done in a cloning fashion:
fd = open("newfile", O_CREAT|O_RDWR, 0644);
fstat(fd, &st);
printf("new file is %d\n", (int)st.st_ino);
Once you have created a file, you can open() and unlink() it by its returned
inode number retrieved from the stat call, ie:
fd = open("5", O_RDWR);
The creation permissions depend entirely if you have write access to the
root directory of the filesystem.
To get the list of currently allocated inodes, VOP_READDIR has been added
which returns a directory listing of those currently allocated.
--
What this entails:
* patching conf/files and conf/options to include IFS as a new compile
option (and since ifs depends upon FFS, include the FFS routines)
* An entry in i386/conf/NOTES indicating IFS exists and where to go for
an explanation
* Unstaticize a couple of routines in src/sys/ufs/ffs/ which the IFS
routines require (ffs_mount() and ffs_reload())
* a new bunch of routines in src/sys/ufs/ifs/ which implement the IFS
routines. IFS replaces some of the vfsops, and a handful of vnops -
most notably are VFS_VGET(), VOP_LOOKUP(), VOP_UNLINK() and VOP_READDIR().
Any other directory operation is marked as invalid.
What this results in:
* an IFS partition's create permissions are controlled by the perm/ownership of
the root mount point, just like a normal directory
* Each inode has perm and ownership too
* IFS does *NOT* mean an FFS partition can be opened per inode. This is a
completely seperate filesystem here
* Softupdates doesn't work with IFS, and really I don't think it needs it.
Besides, fsck's are FAST. (Try it :-)
* Inodes 0 and 1 aren't allocatable because they are special (dump/swap IIRC).
Inode 2 isn't allocatable since UFS/FFS locks all inodes in the system against
this particular inode, and unravelling THAT code isn't trivial. Therefore,
useful inodes start at 3.
Enjoy, and feedback is definitely appreciated!
302 lines
8.9 KiB
C
302 lines
8.9 KiB
C
/*
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* Copyright (c) 1982, 1986, 1989, 1993
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* The Regents of the University of California. 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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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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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* @(#)ffs_vnops.c 8.15 (Berkeley) 5/14/95
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* $FreeBSD$
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*/
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#include "opt_ffs.h"
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/resourcevar.h>
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#include <sys/signalvar.h>
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#include <sys/kernel.h>
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#include <sys/stat.h>
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#include <sys/bio.h>
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#include <sys/buf.h>
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#include <sys/proc.h>
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#include <sys/mount.h>
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#include <sys/vnode.h>
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#include <sys/conf.h>
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#include <machine/limits.h>
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#include <vm/vm.h>
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#include <vm/vm_page.h>
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#include <vm/vm_object.h>
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#include <vm/vm_extern.h>
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#include <ufs/ufs/extattr.h>
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#include <ufs/ufs/quota.h>
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#include <ufs/ufs/inode.h>
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#include <ufs/ufs/ufsmount.h>
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#include <ufs/ufs/ufs_extern.h>
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#include <ufs/ffs/fs.h>
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#include <ufs/ffs/ffs_extern.h>
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int ffs_fsync __P((struct vop_fsync_args *));
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static int ffs_getpages __P((struct vop_getpages_args *));
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static int ffs_putpages __P((struct vop_putpages_args *));
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static int ffs_read __P((struct vop_read_args *));
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static int ffs_write __P((struct vop_write_args *));
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/* Global vfs data structures for ufs. */
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vop_t **ffs_vnodeop_p;
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static struct vnodeopv_entry_desc ffs_vnodeop_entries[] = {
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{ &vop_default_desc, (vop_t *) ufs_vnoperate },
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{ &vop_fsync_desc, (vop_t *) ffs_fsync },
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{ &vop_getpages_desc, (vop_t *) ffs_getpages },
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{ &vop_putpages_desc, (vop_t *) ffs_putpages },
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{ &vop_read_desc, (vop_t *) ffs_read },
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{ &vop_balloc_desc, (vop_t *) ffs_balloc },
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{ &vop_reallocblks_desc, (vop_t *) ffs_reallocblks },
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{ &vop_write_desc, (vop_t *) ffs_write },
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#ifdef FFS_EXTATTR
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{ &vop_getextattr_desc, (vop_t *) ufs_vop_getextattr },
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{ &vop_setextattr_desc, (vop_t *) ufs_vop_setextattr },
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#endif
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{ NULL, NULL }
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};
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static struct vnodeopv_desc ffs_vnodeop_opv_desc =
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{ &ffs_vnodeop_p, ffs_vnodeop_entries };
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vop_t **ffs_specop_p;
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static struct vnodeopv_entry_desc ffs_specop_entries[] = {
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{ &vop_default_desc, (vop_t *) ufs_vnoperatespec },
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{ &vop_fsync_desc, (vop_t *) ffs_fsync },
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{ &vop_copyonwrite_desc, (vop_t *) ffs_copyonwrite },
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#ifdef FFS_EXTATTR
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{ &vop_getextattr_desc, (vop_t *) ufs_vop_getextattr },
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{ &vop_setextattr_desc, (vop_t *) ufs_vop_setextattr },
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#endif
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{ NULL, NULL }
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};
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static struct vnodeopv_desc ffs_specop_opv_desc =
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{ &ffs_specop_p, ffs_specop_entries };
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vop_t **ffs_fifoop_p;
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static struct vnodeopv_entry_desc ffs_fifoop_entries[] = {
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{ &vop_default_desc, (vop_t *) ufs_vnoperatefifo },
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#ifdef FFS_EXTATTR
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{ &vop_getextattr_desc, (vop_t *) ufs_vop_getextattr },
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{ &vop_setextattr_desc, (vop_t *) ufs_vop_setextattr },
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#endif
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{ &vop_fsync_desc, (vop_t *) ffs_fsync },
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{ NULL, NULL }
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};
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static struct vnodeopv_desc ffs_fifoop_opv_desc =
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{ &ffs_fifoop_p, ffs_fifoop_entries };
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VNODEOP_SET(ffs_vnodeop_opv_desc);
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VNODEOP_SET(ffs_specop_opv_desc);
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VNODEOP_SET(ffs_fifoop_opv_desc);
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#include <ufs/ufs/ufs_readwrite.c>
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/*
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* Synch an open file.
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*/
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/* ARGSUSED */
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int
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ffs_fsync(ap)
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struct vop_fsync_args /* {
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struct vnode *a_vp;
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struct ucred *a_cred;
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int a_waitfor;
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struct proc *a_p;
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} */ *ap;
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{
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struct vnode *vp = ap->a_vp;
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struct inode *ip = VTOI(vp);
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struct buf *bp;
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struct buf *nbp;
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int s, error, wait, passes, skipmeta;
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daddr_t lbn;
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/*
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* Snapshots have to be unlocked so they do not deadlock
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* checking whether they need to copy their written buffers.
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* We always hold a reference, so they cannot be removed
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* out from underneath us.
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*/
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if (ip->i_flags & SF_SNAPSHOT)
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VOP_UNLOCK(vp, 0, ap->a_p);
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wait = (ap->a_waitfor == MNT_WAIT);
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if (vn_isdisk(vp, NULL)) {
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lbn = INT_MAX;
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if (vp->v_rdev->si_mountpoint != NULL &&
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(vp->v_rdev->si_mountpoint->mnt_flag & MNT_SOFTDEP))
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softdep_fsync_mountdev(vp);
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} else {
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lbn = lblkno(ip->i_fs, (ip->i_size + ip->i_fs->fs_bsize - 1));
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}
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/*
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* Flush all dirty buffers associated with a vnode.
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*/
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passes = NIADDR + 1;
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skipmeta = 0;
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if (wait)
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skipmeta = 1;
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s = splbio();
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loop:
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for (bp = TAILQ_FIRST(&vp->v_dirtyblkhd); bp;
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bp = TAILQ_NEXT(bp, b_vnbufs))
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bp->b_flags &= ~B_SCANNED;
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for (bp = TAILQ_FIRST(&vp->v_dirtyblkhd); bp; bp = nbp) {
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nbp = TAILQ_NEXT(bp, b_vnbufs);
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/*
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* Reasons to skip this buffer: it has already been considered
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* on this pass, this pass is the first time through on a
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* synchronous flush request and the buffer being considered
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* is metadata, the buffer has dependencies that will cause
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* it to be redirtied and it has not already been deferred,
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* or it is already being written.
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*/
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if ((bp->b_flags & B_SCANNED) != 0)
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continue;
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bp->b_flags |= B_SCANNED;
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if ((skipmeta == 1 && bp->b_lblkno < 0))
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continue;
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if (!wait && LIST_FIRST(&bp->b_dep) != NULL &&
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(bp->b_flags & B_DEFERRED) == 0 &&
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buf_countdeps(bp, 0)) {
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bp->b_flags |= B_DEFERRED;
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continue;
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}
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if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT))
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continue;
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if ((bp->b_flags & B_DELWRI) == 0)
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panic("ffs_fsync: not dirty");
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if (vp != bp->b_vp)
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panic("ffs_fsync: vp != vp->b_vp");
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/*
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* If this is a synchronous flush request, or it is not a
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* file or device, start the write on this buffer immediatly.
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*/
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if (wait || (vp->v_type != VREG && vp->v_type != VBLK)) {
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/*
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* On our final pass through, do all I/O synchronously
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* so that we can find out if our flush is failing
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* because of write errors.
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*/
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if (passes > 0 || !wait) {
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if ((bp->b_flags & B_CLUSTEROK) && !wait) {
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BUF_UNLOCK(bp);
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(void) vfs_bio_awrite(bp);
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} else {
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bremfree(bp);
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splx(s);
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(void) bawrite(bp);
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s = splbio();
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}
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} else {
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bremfree(bp);
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splx(s);
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if ((error = bwrite(bp)) != 0)
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return (error);
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s = splbio();
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}
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} else if ((vp->v_type == VREG) && (bp->b_lblkno >= lbn)) {
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/*
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* If the buffer is for data that has been truncated
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* off the file, then throw it away.
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*/
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bremfree(bp);
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bp->b_flags |= B_INVAL | B_NOCACHE;
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splx(s);
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brelse(bp);
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s = splbio();
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} else {
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BUF_UNLOCK(bp);
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vfs_bio_awrite(bp);
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}
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/*
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* Since we may have slept during the I/O, we need
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* to start from a known point.
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*/
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nbp = TAILQ_FIRST(&vp->v_dirtyblkhd);
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}
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/*
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* If we were asked to do this synchronously, then go back for
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* another pass, this time doing the metadata.
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*/
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if (skipmeta) {
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skipmeta = 0;
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goto loop;
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}
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if (wait) {
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while (vp->v_numoutput) {
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vp->v_flag |= VBWAIT;
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(void) tsleep((caddr_t)&vp->v_numoutput,
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PRIBIO + 4, "ffsfsn", 0);
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}
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/*
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* Ensure that any filesystem metatdata associated
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* with the vnode has been written.
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*/
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splx(s);
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if ((error = softdep_sync_metadata(ap)) != 0)
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return (error);
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s = splbio();
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if (!TAILQ_EMPTY(&vp->v_dirtyblkhd)) {
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/*
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* Block devices associated with filesystems may
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* have new I/O requests posted for them even if
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* the vnode is locked, so no amount of trying will
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* get them clean. Thus we give block devices a
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* good effort, then just give up. For all other file
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* types, go around and try again until it is clean.
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*/
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if (passes > 0) {
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passes -= 1;
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goto loop;
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}
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#ifdef DIAGNOSTIC
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if (!vn_isdisk(vp, NULL))
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vprint("ffs_fsync: dirty", vp);
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#endif
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}
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}
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splx(s);
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error = UFS_UPDATE(vp, wait);
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if (ip->i_flags & SF_SNAPSHOT)
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vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, ap->a_p);
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return (error);
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}
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