260 lines
8.4 KiB
C
260 lines
8.4 KiB
C
/* $NetBSD: umount_linux.c,v 1.1.1.2 2005/09/20 17:15:27 rpaulo Exp $ */
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/*
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* Copyright (c) 1997-2005 Erez Zadok
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* Copyright (c) 1990 Jan-Simon Pendry
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* Copyright (c) 1990 Imperial College of Science, Technology & Medicine
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* Copyright (c) 1990 The Regents of the University of California.
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* All rights reserved.
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*
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* This code is derived from software contributed to Berkeley by
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* Jan-Simon Pendry at Imperial College, London.
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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 acknowledgment:
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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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*
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* File: am-utils/conf/umount/umount_linux.c
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*
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*/
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/*
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* Linux method of unmounting filesystems: if umount(2) failed with EIO or
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* ESTALE, try umount2(2) with MNT_FORCE+MNT_DETACH.
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*/
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#ifdef HAVE_CONFIG_H
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# include <config.h>
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#endif /* HAVE_CONFIG_H */
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#include <am_defs.h>
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#include <amu.h>
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int
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umount_fs(char *mntdir, const char *mnttabname, u_int unmount_flags)
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{
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mntlist *mlist, *mp, *mp_save = 0;
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int error = 0;
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#ifdef HAVE_LOOP_DEVICE
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char *opt, *xopts=NULL;
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char loopstr[] = "loop=";
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char *loopdev;
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#endif /* HAVE_LOOP_DEVICE */
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mp = mlist = read_mtab(mntdir, mnttabname);
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/*
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* Search the mount table looking for
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* the correct (ie last) matching entry
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*/
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while (mp) {
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if (STREQ(mp->mnt->mnt_dir, mntdir))
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mp_save = mp;
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mp = mp->mnext;
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}
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if (!mp_save) {
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plog(XLOG_ERROR, "Couldn't find how to unmount %s", mntdir);
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/* Assume it is already unmounted */
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error = 0;
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goto out;
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}
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dlog("Trying unmount(%s)", mp_save->mnt->mnt_dir);
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#ifdef MOUNT_TABLE_ON_FILE
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/*
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* This unmount may hang leaving this process with an exclusive lock on
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* /etc/mtab. Therefore it is necessary to unlock mtab, do the unmount,
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* then lock mtab (again) and reread it and finally update it.
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*/
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unlock_mntlist();
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#endif /* MOUNT_TABLE_ON_FILE */
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#if defined(HAVE_UMOUNT2) && defined(MNT2_GEN_OPT_DETACH)
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/*
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* If user asked to try forced unmounts, then do a quick check to see if
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* the mount point is hung badly. If so, then try to detach it by
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* force; if the latter works, we're done.
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*/
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if (unmount_flags & AMU_UMOUNT_DETACH) {
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/*
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* Note: we pass both DETACH and FORCE flags, because umount2_fs below
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* (on Linux), should try FORCE before DETACH (the latter always
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* succeeds).
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*/
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error = umount2_fs(mp_save->mnt->mnt_dir,
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unmount_flags & (AMU_UMOUNT_DETACH|AMU_UMOUNT_FORCE));
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} else
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#endif /* defined(HAVE_UMOUNT2) && defined(MNT2_GEN_OPT_DETACH) */
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error = UNMOUNT_TRAP(mp_save->mnt);
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if (error < 0) {
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plog(XLOG_WARNING, "unmount(%s) failed: %m", mp_save->mnt->mnt_dir);
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switch ((error = errno)) {
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case EINVAL:
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case ENOTBLK:
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plog(XLOG_WARNING, "unmount: %s is not mounted", mp_save->mnt->mnt_dir);
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error = 0; /* Not really an error */
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break;
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case ENOENT:
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/*
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* This could happen if the kernel insists on following symlinks
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* when we try to unmount a direct mountpoint. We need to propagate
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* the error up so that the top layers know it failed and don't
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* try to rmdir() the mountpoint or other silly things.
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*/
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plog(XLOG_ERROR, "mount point %s: %m", mp_save->mnt->mnt_dir);
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break;
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#if defined(HAVE_UMOUNT2) && defined(MNT2_GEN_OPT_FORCE)
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case EBUSY:
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/*
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* Caller determines if forced unmounts should be used now (for
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* EBUSY). If caller asked to force an unmount, *and* the above
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* "trivial" unmount attempt failed with EBUSY, then try to force
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* the unmount.
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*/
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if (unmount_flags & AMU_UMOUNT_FORCE) {
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error = umount2_fs(mp_save->mnt->mnt_dir,
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unmount_flags & AMU_UMOUNT_FORCE);
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if (error < 0) {
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plog(XLOG_WARNING, "%s: unmount/force: %m",
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mp_save->mnt->mnt_dir);
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error = errno;
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}
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}
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break;
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#endif /* defined(HAVE_UMOUNT2) && defined(MNT2_GEN_OPT_FORCE) */
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default:
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dlog("%s: unmount: %m", mp_save->mnt->mnt_dir);
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break;
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}
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} else {
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dlog("unmount(%s) succeeded", mp_save->mnt->mnt_dir);
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}
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dlog("Finished unmount(%s)", mp_save->mnt->mnt_dir);
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/*
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* If we are successful or there was an ENOENT, remove
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* the mount entry from the mtab file.
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*/
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if (error && error != ENOENT)
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goto out;
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#ifdef HAVE_LOOP_DEVICE
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/* look for loop=/dev/loopX in mnt_opts */
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xopts = strdup(mp_save->mnt->mnt_opts); /* b/c strtok is destructive */
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for (opt = strtok(xopts, ","); opt; opt = strtok(NULL, ","))
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if (NSTREQ(opt, loopstr, sizeof(loopstr) - 1)) {
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loopdev = opt + sizeof(loopstr) - 1;
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if (delete_loop_device(loopdev) < 0)
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plog(XLOG_WARNING, "unmount() failed to release loop device %s: %m", loopdev);
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else
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plog(XLOG_INFO, "unmount() released loop device %s OK", loopdev);
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break;
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}
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if (xopts)
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XFREE(xopts);
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#endif /* HAVE_LOOP_DEVICE */
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#ifdef MOUNT_TABLE_ON_FILE
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free_mntlist(mlist);
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mp = mlist = read_mtab(mntdir, mnttabname);
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/*
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* Search the mount table looking for
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* the correct (ie last) matching entry
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*/
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mp_save = 0;
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while (mp) {
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if (STREQ(mp->mnt->mnt_dir, mntdir))
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mp_save = mp;
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mp = mp->mnext;
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}
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if (mp_save) {
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mnt_free(mp_save->mnt);
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mp_save->mnt = 0;
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rewrite_mtab(mlist, mnttabname);
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}
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#endif /* MOUNT_TABLE_ON_FILE */
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out:
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free_mntlist(mlist);
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return error;
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}
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#if defined(HAVE_UMOUNT2) && (defined(MNT2_GEN_OPT_FORCE) || defined(MNT2_GEN_OPT_DETACH))
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/*
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* Force unmount, no questions asked, without touching mnttab file. Try
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* detach first because it is safer: will remove the hung mnt point without
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* affecting hung applications. "Force" is more risky: it will cause the
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* kernel to return EIO to applications stuck on a stat(2) of Amd.
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*/
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int
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umount2_fs(const char *mntdir, u_int unmount_flags)
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{
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int error = 0;
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#ifdef MNT2_GEN_OPT_DETACH
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if (unmount_flags & AMU_UMOUNT_DETACH) {
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error = umount2(mntdir, MNT2_GEN_OPT_DETACH);
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if (error < 0 && (errno == EINVAL || errno == ENOENT))
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error = 0; /* ignore EINVAL/ENOENT */
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if (error < 0) { /* don't try FORCE if detach succeeded */
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plog(XLOG_WARNING, "%s: unmount/detach: %m", mntdir);
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/* fall through to try "force" (if flag specified) */
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} else {
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dlog("%s: unmount/detach: OK", mntdir);
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return error;
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}
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}
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#endif /* MNT2_GEN_OPT_DETACH */
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#ifdef MNT2_GEN_OPT_FORCE
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if (unmount_flags & AMU_UMOUNT_FORCE) {
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plog(XLOG_INFO, "umount2_fs: trying unmount/forced on %s", mntdir);
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error = umount2(mntdir, MNT2_GEN_OPT_FORCE);
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if (error < 0 && (errno == EINVAL || errno == ENOENT))
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error = 0; /* ignore EINVAL/ENOENT */
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if (error < 0)
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plog(XLOG_WARNING, "%s: unmount/force: %m", mntdir);
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else
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dlog("%s: unmount/force: OK", mntdir);
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/* fall through to return whatever error we got (if any) */
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}
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#endif /* MNT2_GEN_OPT_FORCE */
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return error;
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}
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#endif /* HAVE_UMOUNT2 && (MNT2_GEN_OPT_FORCE || MNT2_GEN_OPT_DETACH) */
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