2 * Copyright (c) 2012 The FreeBSD Foundation
5 * This software was developed by Edward Tomasz Napierala under sponsorship
6 * from the FreeBSD Foundation.
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 #include <sys/cdefs.h>
33 __FBSDID("$FreeBSD$");
35 #include <sys/param.h>
36 #include <sys/systm.h>
38 #include <sys/ioccom.h>
39 #include <sys/mount.h>
40 #include <sys/vnode.h>
45 #include <security/mac/mac_framework.h>
47 #include <ufs/ufs/extattr.h>
48 #include <ufs/ufs/quota.h>
49 #include <ufs/ufs/ufsmount.h>
50 #include <ufs/ufs/inode.h>
52 #include <ufs/ffs/fs.h>
53 #include <ufs/ffs/ffs_extern.h>
55 static d_open_t ffs_susp_open;
56 static d_write_t ffs_susp_rdwr;
57 static d_ioctl_t ffs_susp_ioctl;
59 static struct cdevsw ffs_susp_cdevsw = {
60 .d_version = D_VERSION,
61 .d_open = ffs_susp_open,
62 .d_read = ffs_susp_rdwr,
63 .d_write = ffs_susp_rdwr,
64 .d_ioctl = ffs_susp_ioctl,
68 static struct cdev *ffs_susp_dev;
69 static struct sx ffs_susp_lock;
72 ffs_susp_suspended(struct mount *mp)
76 sx_assert(&ffs_susp_lock, SA_LOCKED);
79 if (ump->um_writesuspended)
85 ffs_susp_open(struct cdev *dev __unused, int flags __unused,
86 int fmt __unused, struct thread *td __unused)
93 ffs_susp_rdwr(struct cdev *dev, struct uio *uio, int ioflag)
105 sx_slock(&ffs_susp_lock);
107 error = devfs_get_cdevpriv((void **)&mp);
109 sx_sunlock(&ffs_susp_lock);
114 devvp = ump->um_devvp;
117 if (ffs_susp_suspended(mp) == 0) {
118 sx_sunlock(&ffs_susp_lock);
122 KASSERT(uio->uio_rw == UIO_READ || uio->uio_rw == UIO_WRITE,
123 ("neither UIO_READ or UIO_WRITE"));
124 KASSERT(uio->uio_segflg == UIO_USERSPACE,
125 ("uio->uio_segflg != UIO_USERSPACE"));
127 cnt = uio->uio_resid;
129 for (i = 0; i < uio->uio_iovcnt; i++) {
130 while (uio->uio_iov[i].iov_len) {
131 base = uio->uio_iov[i].iov_base;
132 len = uio->uio_iov[i].iov_len;
133 if (len > fs->fs_bsize)
135 if (fragoff(fs, uio->uio_offset) != 0 ||
136 fragoff(fs, len) != 0) {
140 error = bread(devvp, btodb(uio->uio_offset), len,
144 if (uio->uio_rw == UIO_WRITE) {
145 error = copyin(base, bp->b_data, len);
147 bp->b_flags |= B_INVAL | B_NOCACHE;
155 error = copyout(bp->b_data, base, len);
160 uio->uio_iov[i].iov_base =
161 (char *)uio->uio_iov[i].iov_base + len;
162 uio->uio_iov[i].iov_len -= len;
163 uio->uio_resid -= len;
164 uio->uio_offset += len;
169 sx_sunlock(&ffs_susp_lock);
171 if (uio->uio_resid < cnt)
178 ffs_susp_suspend(struct mount *mp)
180 struct ufsmount *ump;
183 sx_assert(&ffs_susp_lock, SA_XLOCKED);
185 if (!ffs_own_mount(mp))
187 if (ffs_susp_suspended(mp))
193 * Make sure the calling thread is permitted to access the mounted
194 * device. The permissions can change after we unlock the vnode;
197 vn_lock(ump->um_devvp, LK_EXCLUSIVE | LK_RETRY);
198 error = VOP_ACCESS(ump->um_devvp, VREAD | VWRITE,
199 curthread->td_ucred, curthread);
200 VOP_UNLOCK(ump->um_devvp, 0);
204 if (mac_mount_check_stat(curthread->td_ucred, mp) != 0)
208 if ((error = vfs_write_suspend(mp, VS_SKIP_UNMOUNT)) != 0)
211 ump->um_writesuspended = 1;
217 ffs_susp_dtor(void *data)
220 struct ufsmount *ump;
224 sx_xlock(&ffs_susp_lock);
226 mp = (struct mount *)data;
230 if (ffs_susp_suspended(mp) == 0) {
231 sx_xunlock(&ffs_susp_lock);
235 KASSERT((mp->mnt_kern_flag & MNTK_SUSPEND) != 0,
236 ("MNTK_SUSPEND not set"));
238 error = ffs_reload(mp, curthread, FFSR_FORCE | FFSR_UNSUSPEND);
240 panic("failed to unsuspend writes on %s", fs->fs_fsmnt);
243 * XXX: The status is kept per-process; the vfs_write_resume() routine
244 * asserts that the resuming thread is the same one that called
245 * vfs_write_suspend(). The cdevpriv data, however, is attached
246 * to the file descriptor, e.g. is inherited during fork. Thus,
247 * it's possible that the resuming process will be different from
248 * the one that started the suspension.
250 * Work around by fooling the check in vfs_write_resume().
252 mp->mnt_susp_owner = curthread;
254 vfs_write_resume(mp, 0);
256 ump->um_writesuspended = 0;
258 sx_xunlock(&ffs_susp_lock);
262 ffs_susp_ioctl(struct cdev *dev, u_long cmd, caddr_t addr, int flags,
270 * No suspend inside the jail. Allowing it would require making
271 * sure that e.g. the devfs ruleset for that jail permits access
274 if (jailed(td->td_ucred))
277 sx_xlock(&ffs_susp_lock);
281 fsidp = (fsid_t *)addr;
282 mp = vfs_getvfs(fsidp);
287 error = vfs_busy(mp, 0);
291 error = ffs_susp_suspend(mp);
296 error = devfs_set_cdevpriv(mp, ffs_susp_dtor);
297 KASSERT(error == 0, ("devfs_set_cdevpriv failed"));
300 error = devfs_get_cdevpriv((void **)&mp);
304 * This calls ffs_susp_dtor, which in turn unsuspends the fs.
305 * The dtor expects to be called without lock held, because
306 * sometimes it's called from here, and sometimes due to the
307 * file being closed or process exiting.
309 sx_xunlock(&ffs_susp_lock);
310 devfs_clear_cdevpriv();
317 sx_xunlock(&ffs_susp_lock);
323 ffs_susp_initialize(void)
326 sx_init(&ffs_susp_lock, "ffs_susp");
327 ffs_susp_dev = make_dev(&ffs_susp_cdevsw, 0, UID_ROOT, GID_WHEEL, 0600,
332 ffs_susp_uninitialize(void)
335 destroy_dev(ffs_susp_dev);
336 sx_destroy(&ffs_susp_lock);