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Differential D27269 Diff 79749 sys/fs/msdosfs/msdosfs_vfsops.c

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sys/fs/msdosfs/msdosfs_vfsops.c

Show First 20 Lines • Show All 242 Lines • ▼ Show 20 Linesmsdosfs_mount(struct mount *mp)
/* /*
* If updating, check whether changing from read-only to * If updating, check whether changing from read-only to
* read/write; if there is no device name, that's all we do. * read/write; if there is no device name, that's all we do.
*/ */
if (mp->mnt_flag & MNT_UPDATE) { if (mp->mnt_flag & MNT_UPDATE) {
pmp = VFSTOMSDOSFS(mp); pmp = VFSTOMSDOSFS(mp);
if (!(pmp->pm_flags & MSDOSFSMNT_RONLY) && if (!(pmp->pm_flags & MSDOSFSMNT_RONLY) &&
vfs_flagopt(mp->mnt_optnew, "ro", NULL, 0)) { vfs_flagopt(mp->mnt_optnew, "ro", NULL, 0)) {
error = VFS_SYNC(mp, MNT_WAIT); if ((error = vn_start_write(NULL, &mp, V_WAIT)) != 0)
if (error)
return (error); return (error);
error = vfs_write_suspend_umnt(mp);
if (error != 0)
return (error);
flags = WRITECLOSE; flags = WRITECLOSE;
if (mp->mnt_flag & MNT_FORCE) if (mp->mnt_flag & MNT_FORCE)
flags |= FORCECLOSE; flags |= FORCECLOSE;
error = vflush(mp, 0, flags, td); error = vflush(mp, 0, flags, td);
if (error) if (error != 0) {
vfs_write_resume(mp, 0);
return (error); return (error);
}
/* /*
* Now the volume is clean. Mark it so while the * Now the volume is clean. Mark it so while the
* device is still rw. * device is still rw.
*/ */
error = markvoldirty(pmp, 0); error = markvoldirty(pmp, 0);
if (error) { if (error != 0) {
vfs_write_resume(mp, 0);
(void)markvoldirty(pmp, 1); (void)markvoldirty(pmp, 1);
return (error); return (error);
} }
/* Downgrade the device from rw to ro. */ /* Downgrade the device from rw to ro. */
g_topology_lock(); g_topology_lock();
error = g_access(pmp->pm_cp, 0, -1, 0); error = g_access(pmp->pm_cp, 0, -1, 0);
g_topology_unlock(); g_topology_unlock();
if (error) { if (error) {
vfs_write_resume(mp, 0);
(void)markvoldirty(pmp, 1); (void)markvoldirty(pmp, 1);
return (error); return (error);
} }
/* /*
* Backing out after an error was painful in the * Backing out after an error was painful in the
* above. Now we are committed to succeeding. * above. Now we are committed to succeeding.
*/ */
pmp->pm_fmod = 0; pmp->pm_fmod = 0;
pmp->pm_flags |= MSDOSFSMNT_RONLY; pmp->pm_flags |= MSDOSFSMNT_RONLY;
MNT_ILOCK(mp); MNT_ILOCK(mp);
mp->mnt_flag |= MNT_RDONLY; mp->mnt_flag |= MNT_RDONLY;
MNT_IUNLOCK(mp); MNT_IUNLOCK(mp);
vfs_write_resume(mp, 0);
} else if ((pmp->pm_flags & MSDOSFSMNT_RONLY) && } else if ((pmp->pm_flags & MSDOSFSMNT_RONLY) &&
!vfs_flagopt(mp->mnt_optnew, "ro", NULL, 0)) { !vfs_flagopt(mp->mnt_optnew, "ro", NULL, 0)) {
/* /*
* If upgrade to read-write by non-root, then verify * If upgrade to read-write by non-root, then verify
* that user has necessary permissions on the device. * that user has necessary permissions on the device.
*/ */
devvp = pmp->pm_devvp; devvp = pmp->pm_devvp;
vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY); vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY);
▲ Show 20 Lines • Show All 447 Lines • ▼ Show 20 Lines
/* /*
* Unmount the filesystem described by mp. * Unmount the filesystem described by mp.
*/ */
static int static int
msdosfs_unmount(struct mount *mp, int mntflags) msdosfs_unmount(struct mount *mp, int mntflags)
{ {
struct msdosfsmount *pmp; struct msdosfsmount *pmp;
int error, flags; int error, flags;
bool susp;
error = flags = 0; error = flags = 0;
pmp = VFSTOMSDOSFS(mp); pmp = VFSTOMSDOSFS(mp);
if ((pmp->pm_flags & MSDOSFSMNT_RONLY) == 0) susp = (pmp->pm_flags & MSDOSFSMNT_RONLY) != 0;
error = msdosfs_sync(mp, MNT_WAIT);
if (susp) {
error = vfs_write_suspend_umnt(mp);
if (error != 0)
return (error);
}
if ((mntflags & MNT_FORCE) != 0) if ((mntflags & MNT_FORCE) != 0)
flags |= FORCECLOSE; flags |= FORCECLOSE;
else if (error != 0)
return (error);
error = vflush(mp, 0, flags, curthread); error = vflush(mp, 0, flags, curthread);
if (error != 0 && error != ENXIO) if (error != 0 && error != ENXIO) {
if (susp)
vfs_write_resume(mp, VR_START_WRITE);
return (error); return (error);
if ((pmp->pm_flags & MSDOSFSMNT_RONLY) == 0) { }
if (susp) {
error = markvoldirty(pmp, 0); error = markvoldirty(pmp, 0);
if (error && error != ENXIO) { if (error != 0 && error != ENXIO) {
if (susp)
vfs_write_resume(mp, VR_START_WRITE);
(void)markvoldirty(pmp, 1); (void)markvoldirty(pmp, 1);
return (error); return (error);
} }
} }
if (pmp->pm_flags & MSDOSFSMNT_KICONV && msdosfs_iconv) { if (pmp->pm_flags & MSDOSFSMNT_KICONV && msdosfs_iconv) {
if (pmp->pm_w2u) if (pmp->pm_w2u)
msdosfs_iconv->close(pmp->pm_w2u); msdosfs_iconv->close(pmp->pm_w2u);
if (pmp->pm_u2w) if (pmp->pm_u2w)
Show All 20 Lines#ifdef MSDOSFS_DEBUG
printf("cleanblkhd %p, dirtyblkhd %p, numoutput %ld, type %d\n", printf("cleanblkhd %p, dirtyblkhd %p, numoutput %ld, type %d\n",
TAILQ_FIRST(&vp->v_bufobj.bo_clean.bv_hd), TAILQ_FIRST(&vp->v_bufobj.bo_clean.bv_hd),
TAILQ_FIRST(&vp->v_bufobj.bo_dirty.bv_hd), TAILQ_FIRST(&vp->v_bufobj.bo_dirty.bv_hd),
vp->v_bufobj.bo_numoutput, vp->v_type); vp->v_bufobj.bo_numoutput, vp->v_type);
VI_UNLOCK(vp); VI_UNLOCK(vp);
BO_UNLOCK(bo); BO_UNLOCK(bo);
} }
#endif #endif
if (susp)
vfs_write_resume(mp, VR_START_WRITE);
impUnsubmitted
Done
Inline Actions

Why do we need to resume writes if we're unmounting and near the end of that process? Is this a precondition for something else?

imp: Why do we need to resume writes if we're unmounting and near the end of that process? Is this a…
kibAuthorUnsubmitted
Done
Inline Actions

Draining mount point for safe state in vfs_mount_destroy() checks that there is no active writers when mp is destroyed.

VFS guarantees that no new consumers can enter mp when VFS_UNMOUNT() is called, so this is a precaution against bugs in this area, and calls to vfs_write_resume() restore invariant that is assumed by the unmount code.

kib: Draining mount point for safe state in vfs_mount_destroy() checks that there is no active…
g_topology_lock(); g_topology_lock();
g_vfs_close(pmp->pm_cp); g_vfs_close(pmp->pm_cp);
g_topology_unlock(); g_topology_unlock();
atomic_store_rel_ptr((uintptr_t *)&pmp->pm_dev->si_mountpt, 0); atomic_store_rel_ptr((uintptr_t *)&pmp->pm_dev->si_mountpt, 0);
vrele(pmp->pm_devvp); vrele(pmp->pm_devvp);
dev_rel(pmp->pm_dev); dev_rel(pmp->pm_dev);
free(pmp->pm_inusemap, M_MSDOSFSFAT); free(pmp->pm_inusemap, M_MSDOSFSFAT);
lockdestroy(&pmp->pm_fatlock); lockdestroy(&pmp->pm_fatlock);
▲ Show 20 Lines • Show All 134 Lines • ▼ Show 20 Lines if (waitfor != MNT_LAZY) {
if (error) if (error)
allerror = error; allerror = error;
VOP_UNLOCK(pmp->pm_devvp); VOP_UNLOCK(pmp->pm_devvp);
} }
error = msdosfs_fsiflush(pmp, waitfor); error = msdosfs_fsiflush(pmp, waitfor);
if (error != 0) if (error != 0)
allerror = error; allerror = error;
if (allerror == 0 && waitfor == MNT_SUSPEND) {
MNT_ILOCK(mp);
mp->mnt_kern_flag |= MNTK_SUSPEND2 | MNTK_SUSPENDED;
MNT_IUNLOCK(mp);
}
return (allerror); return (allerror);
} }
static int static int
msdosfs_fhtovp(struct mount *mp, struct fid *fhp, int flags, struct vnode **vpp) msdosfs_fhtovp(struct mount *mp, struct fid *fhp, int flags, struct vnode **vpp)
{ {
struct msdosfsmount *pmp = VFSTOMSDOSFS(mp); struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
struct defid *defhp = (struct defid *) fhp; struct defid *defhp = (struct defid *) fhp;
Show All 25 Lines