File: [cvs.NetBSD.org] / src / sys / ufs / ffs / ffs_snapshot.c (download)
Revision 1.55, Sun Dec 2 13:56:20 2007 UTC (16 years, 4 months ago) by hannken
Branch: MAIN
CVS Tags: vmlocking2-base2, vmlocking2-base1, vmlocking-nbase, reinoud-bufcleanup-nbase, reinoud-bufcleanup-base
Branch point for: vmlocking2
Changes since 1.54: +7 -5
lines
Fscow_run(): add a flag "bool data_valid" to note still valid data.
Buffers run through copy-on-write are marked B_COWDONE. This condition
is valid until the buffer has run through bwrite() and gets cleared from
biodone().
Welcome to 4.99.39.
Reviewed by: YAMAMOTO Takashi <yamt@netbsd.org>
|
/* $NetBSD: ffs_snapshot.c,v 1.55 2007/12/02 13:56:20 hannken Exp $ */
/*
* Copyright 2000 Marshall Kirk McKusick. All Rights Reserved.
*
* Further information about snapshots can be obtained from:
*
* Marshall Kirk McKusick http://www.mckusick.com/softdep/
* 1614 Oxford Street mckusick@mckusick.com
* Berkeley, CA 94709-1608 +1-510-843-9542
* USA
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY MARSHALL KIRK MCKUSICK ``AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL MARSHALL KIRK MCKUSICK BE LIABLE FOR
* ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)ffs_snapshot.c 8.11 (McKusick) 7/23/00
*
* from FreeBSD: ffs_snapshot.c,v 1.79 2004/02/13 02:02:06 kuriyama Exp
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: ffs_snapshot.c,v 1.55 2007/12/02 13:56:20 hannken Exp $");
#if defined(_KERNEL_OPT)
#include "opt_ffs.h"
#endif
#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/systm.h>
#include <sys/conf.h>
#include <sys/buf.h>
#include <sys/proc.h>
#include <sys/namei.h>
#include <sys/sched.h>
#include <sys/stat.h>
#include <sys/malloc.h>
#include <sys/mount.h>
#include <sys/resource.h>
#include <sys/resourcevar.h>
#include <sys/vnode.h>
#include <sys/kauth.h>
#include <sys/fstrans.h>
#include <miscfs/specfs/specdev.h>
#include <ufs/ufs/quota.h>
#include <ufs/ufs/ufsmount.h>
#include <ufs/ufs/inode.h>
#include <ufs/ufs/ufs_extern.h>
#include <ufs/ufs/ufs_bswap.h>
#include <ufs/ffs/fs.h>
#include <ufs/ffs/ffs_extern.h>
/* FreeBSD -> NetBSD conversion */
#define KERNCRED lwp0.l_cred
#define ufs1_daddr_t int32_t
#define ufs2_daddr_t int64_t
#define ufs_lbn_t daddr_t
#define VI_MTX(v) (&(v)->v_interlock)
#define VI_LOCK(v) simple_lock(&(v)->v_interlock)
#define VI_UNLOCK(v) simple_unlock(&(v)->v_interlock)
#define MNT_ILOCK(v) simple_lock(&mntvnode_slock)
#define MNT_IUNLOCK(v) simple_unlock(&mntvnode_slock)
#if !defined(FFS_NO_SNAPSHOT)
static int cgaccount(int, struct vnode *, void *, int);
static int expunge_ufs1(struct vnode *, struct inode *, struct fs *,
int (*)(struct vnode *, ufs1_daddr_t *, ufs1_daddr_t *, struct fs *,
ufs_lbn_t, int), int);
static int indiracct_ufs1(struct vnode *, struct vnode *, int,
ufs1_daddr_t, ufs_lbn_t, ufs_lbn_t, ufs_lbn_t, ufs_lbn_t, struct fs *,
int (*)(struct vnode *, ufs1_daddr_t *, ufs1_daddr_t *, struct fs *,
ufs_lbn_t, int), int);
static int fullacct_ufs1(struct vnode *, ufs1_daddr_t *, ufs1_daddr_t *,
struct fs *, ufs_lbn_t, int);
static int snapacct_ufs1(struct vnode *, ufs1_daddr_t *, ufs1_daddr_t *,
struct fs *, ufs_lbn_t, int);
static int mapacct_ufs1(struct vnode *, ufs1_daddr_t *, ufs1_daddr_t *,
struct fs *, ufs_lbn_t, int);
static int expunge_ufs2(struct vnode *, struct inode *, struct fs *,
int (*)(struct vnode *, ufs2_daddr_t *, ufs2_daddr_t *, struct fs *,
ufs_lbn_t, int), int);
static int indiracct_ufs2(struct vnode *, struct vnode *, int,
ufs2_daddr_t, ufs_lbn_t, ufs_lbn_t, ufs_lbn_t, ufs_lbn_t, struct fs *,
int (*)(struct vnode *, ufs2_daddr_t *, ufs2_daddr_t *, struct fs *,
ufs_lbn_t, int), int);
static int fullacct_ufs2(struct vnode *, ufs2_daddr_t *, ufs2_daddr_t *,
struct fs *, ufs_lbn_t, int);
static int snapacct_ufs2(struct vnode *, ufs2_daddr_t *, ufs2_daddr_t *,
struct fs *, ufs_lbn_t, int);
static int mapacct_ufs2(struct vnode *, ufs2_daddr_t *, ufs2_daddr_t *,
struct fs *, ufs_lbn_t, int);
static int readvnblk(struct vnode *, void *, ufs2_daddr_t);
#endif /* !defined(FFS_NO_SNAPSHOT) */
static void si_mount_dtor(void *);
static struct snap_info *si_mount_init(struct mount *);
static int ffs_copyonwrite(void *, struct buf *, bool);
static int readfsblk(struct vnode *, void *, ufs2_daddr_t);
static int writevnblk(struct vnode *, void *, ufs2_daddr_t);
static inline int cow_enter(void);
static inline void cow_leave(int);
static inline ufs2_daddr_t db_get(struct inode *, int);
static inline void db_assign(struct inode *, int, ufs2_daddr_t);
static inline ufs2_daddr_t idb_get(struct inode *, void *, int);
static inline void idb_assign(struct inode *, void *, int, ufs2_daddr_t);
struct snap_info {
kmutex_t si_lock; /* Lock this snapinfo */
struct lock si_vnlock; /* Snapshot vnode common lock */
TAILQ_HEAD(inodelst, inode) si_snapshots; /* List of active snapshots */
daddr_t *si_snapblklist; /* Snapshot block hints list */
uint32_t si_gen; /* Incremented on change */
};
#ifdef DEBUG
static int snapdebug = 0;
#endif
static kmutex_t si_mount_init_lock;
static specificdata_key_t si_mount_data_key;
void
ffs_snapshot_init(void)
{
int error;
error = mount_specific_key_create(&si_mount_data_key, si_mount_dtor);
KASSERT(error == 0);
mutex_init(&si_mount_init_lock, MUTEX_DEFAULT, IPL_NONE);
}
void
ffs_snapshot_fini(void)
{
mount_specific_key_delete(si_mount_data_key);
mutex_destroy(&si_mount_init_lock);
}
static void
si_mount_dtor(void *arg)
{
struct snap_info *si = arg;
KASSERT(TAILQ_EMPTY(&si->si_snapshots));
mutex_destroy(&si->si_lock);
KASSERT(si->si_snapblklist == NULL);
free(si, M_MOUNT);
}
static struct snap_info *
si_mount_init(struct mount *mp)
{
struct snap_info *new;
mutex_enter(&si_mount_init_lock);
if ((new = mount_getspecific(mp, si_mount_data_key)) != NULL) {
mutex_exit(&si_mount_init_lock);
return new;
}
new = malloc(sizeof(*new), M_MOUNT, M_WAITOK);
TAILQ_INIT(&new->si_snapshots);
mutex_init(&new->si_lock, MUTEX_DEFAULT, IPL_NONE);
new->si_gen = 0;
new->si_snapblklist = NULL;
mount_setspecific(mp, si_mount_data_key, new);
mutex_exit(&si_mount_init_lock);
return new;
}
/*
* Create a snapshot file and initialize it for the filesystem.
* Vnode is locked on entry and return.
*/
int
ffs_snapshot(struct mount *mp, struct vnode *vp,
struct timespec *ctime)
{
#if defined(FFS_NO_SNAPSHOT)
return EOPNOTSUPP;
}
#else /* defined(FFS_NO_SNAPSHOT) */
ufs2_daddr_t numblks, blkno, *blkp, snaplistsize = 0, *snapblklist;
int error, ns, cg, snaploc;
int i, s, size, len, loc;
int flag = mp->mnt_flag;
struct timeval starttime;
#ifdef DEBUG
struct timeval endtime;
#endif
struct timespec ts;
long redo = 0;
int32_t *lp;
void *space;
void *sbbuf = NULL;
struct fs *copy_fs = NULL, *fs = VFSTOUFS(mp)->um_fs;
struct lwp *l = curlwp;
struct inode *ip, *xp;
struct buf *bp, *ibp, *nbp;
struct vattr vat;
struct vnode *xvp, *nvp, *devvp;
struct snap_info *si;
ns = UFS_FSNEEDSWAP(fs);
if ((si = mount_getspecific(mp, si_mount_data_key)) == NULL)
si = si_mount_init(mp);
/*
* Need to serialize access to snapshot code per filesystem.
*/
/*
* If the vnode already is a snapshot, return.
*/
if (VTOI(vp)->i_flags & SF_SNAPSHOT) {
if (ctime) {
ctime->tv_sec = DIP(VTOI(vp), mtime);
ctime->tv_nsec = DIP(VTOI(vp), mtimensec);
}
return 0;
}
/*
* Check mount, exclusive reference and owner.
*/
if (vp->v_mount != mp)
return EXDEV;
if (vp->v_usecount != 1 || vp->v_writecount != 0)
return EBUSY;
if (kauth_authorize_generic(l->l_cred, KAUTH_GENERIC_ISSUSER,
NULL) != 0 &&
VTOI(vp)->i_uid != kauth_cred_geteuid(l->l_cred))
return EACCES;
if (vp->v_size != 0) {
error = ffs_truncate(vp, 0, 0, NOCRED, l);
if (error)
return error;
}
/*
* Assign a snapshot slot in the superblock.
*/
for (snaploc = 0; snaploc < FSMAXSNAP; snaploc++)
if (fs->fs_snapinum[snaploc] == 0)
break;
if (snaploc == FSMAXSNAP)
return (ENOSPC);
ip = VTOI(vp);
devvp = ip->i_devvp;
/*
* Write an empty list of preallocated blocks to the end of
* the snapshot to set size to at least that of the filesystem.
*/
numblks = howmany(fs->fs_size, fs->fs_frag);
blkno = 1;
blkno = ufs_rw64(blkno, ns);
error = vn_rdwr(UIO_WRITE, vp,
(void *)&blkno, sizeof(blkno), lblktosize(fs, (off_t)numblks),
UIO_SYSSPACE, IO_NODELOCKED|IO_UNIT, l->l_cred, NULL, NULL);
if (error)
goto out;
/*
* Preallocate critical data structures so that we can copy
* them in without further allocation after we suspend all
* operations on the filesystem. We would like to just release
* the allocated buffers without writing them since they will
* be filled in below once we are ready to go, but this upsets
* the soft update code, so we go ahead and write the new buffers.
*
* Allocate all indirect blocks and mark all of them as not
* needing to be copied.
*/
for (blkno = NDADDR; blkno < numblks; blkno += NINDIR(fs)) {
error = ffs_balloc(vp, lblktosize(fs, (off_t)blkno),
fs->fs_bsize, l->l_cred, B_METAONLY, &ibp);
if (error)
goto out;
bawrite(ibp);
}
/*
* Allocate copies for the superblock and its summary information.
*/
error = ffs_balloc(vp, fs->fs_sblockloc, fs->fs_sbsize, KERNCRED,
0, &nbp);
if (error)
goto out;
bawrite(nbp);
blkno = fragstoblks(fs, fs->fs_csaddr);
len = howmany(fs->fs_cssize, fs->fs_bsize);
for (loc = 0; loc < len; loc++) {
error = ffs_balloc(vp, lblktosize(fs, (off_t)(blkno + loc)),
fs->fs_bsize, KERNCRED, 0, &nbp);
if (error)
goto out;
bawrite(nbp);
}
/*
* Copy all the cylinder group maps. Although the
* filesystem is still active, we hope that only a few
* cylinder groups will change between now and when we
* suspend operations. Thus, we will be able to quickly
* touch up the few cylinder groups that changed during
* the suspension period.
*/
len = howmany(fs->fs_ncg, NBBY);
fs->fs_active = malloc(len, M_DEVBUF, M_WAITOK | M_ZERO);
for (cg = 0; cg < fs->fs_ncg; cg++) {
if ((error = ffs_balloc(vp, lfragtosize(fs, cgtod(fs, cg)),
fs->fs_bsize, KERNCRED, 0, &nbp)) != 0)
goto out;
error = cgaccount(cg, vp, nbp->b_data, 1);
bawrite(nbp);
if (error)
goto out;
}
/*
* Change inode to snapshot type file.
*/
ip->i_flags |= SF_SNAPSHOT;
DIP_ASSIGN(ip, flags, ip->i_flags);
ip->i_flag |= IN_CHANGE | IN_UPDATE;
/*
* Ensure that the snapshot is completely on disk.
* Since we have marked it as a snapshot it is safe to
* unlock it as no process will be allowed to write to it.
*/
if ((error = VOP_FSYNC(vp, KERNCRED, FSYNC_WAIT, 0, 0)) != 0)
goto out;
VOP_UNLOCK(vp, 0);
/*
* All allocations are done, so we can now snapshot the system.
*
* Suspend operation on filesystem.
*/
if ((error = vfs_suspend(vp->v_mount, 0)) != 0) {
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
goto out;
}
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
getmicrotime(&starttime);
/*
* First, copy all the cylinder group maps that have changed.
*/
for (cg = 0; cg < fs->fs_ncg; cg++) {
if (ACTIVECG_ISSET(fs, cg))
continue;
redo++;
if ((error = ffs_balloc(vp, lfragtosize(fs, cgtod(fs, cg)),
fs->fs_bsize, KERNCRED, 0, &nbp)) != 0)
goto out1;
error = cgaccount(cg, vp, nbp->b_data, 2);
bawrite(nbp);
if (error)
goto out1;
}
/*
* Grab a copy of the superblock and its summary information.
* We delay writing it until the suspension is released below.
*/
sbbuf = malloc(fs->fs_bsize, M_UFSMNT, M_WAITOK);
loc = blkoff(fs, fs->fs_sblockloc);
if (loc > 0)
memset(sbbuf, 0, loc);
copy_fs = (struct fs *)((char *)sbbuf + loc);
bcopy(fs, copy_fs, fs->fs_sbsize);
size = fs->fs_bsize < SBLOCKSIZE ? fs->fs_bsize : SBLOCKSIZE;
if (fs->fs_sbsize < size)
memset((char *)sbbuf + loc + fs->fs_sbsize, 0,
size - fs->fs_sbsize);
size = blkroundup(fs, fs->fs_cssize);
if (fs->fs_contigsumsize > 0)
size += fs->fs_ncg * sizeof(int32_t);
space = malloc((u_long)size, M_UFSMNT, M_WAITOK);
copy_fs->fs_csp = space;
bcopy(fs->fs_csp, copy_fs->fs_csp, fs->fs_cssize);
space = (char *)space + fs->fs_cssize;
loc = howmany(fs->fs_cssize, fs->fs_fsize);
i = fs->fs_frag - loc % fs->fs_frag;
len = (i == fs->fs_frag) ? 0 : i * fs->fs_fsize;
if (len > 0) {
if ((error = bread(devvp, fsbtodb(fs, fs->fs_csaddr + loc),
len, KERNCRED, &bp)) != 0) {
brelse(bp, 0);
free(copy_fs->fs_csp, M_UFSMNT);
goto out1;
}
bcopy(bp->b_data, space, (u_int)len);
space = (char *)space + len;
brelse(bp, BC_INVAL | BC_NOCACHE);
}
if (fs->fs_contigsumsize > 0) {
copy_fs->fs_maxcluster = lp = space;
for (i = 0; i < fs->fs_ncg; i++)
*lp++ = fs->fs_contigsumsize;
}
/*
* We must check for active files that have been unlinked
* (e.g., with a zero link count). We have to expunge all
* trace of these files from the snapshot so that they are
* not reclaimed prematurely by fsck or unnecessarily dumped.
* We turn off the MNTK_SUSPENDED flag to avoid a panic from
* spec_strategy about writing on a suspended filesystem.
* Note that we skip unlinked snapshot files as they will
* be handled separately below.
*
* We also calculate the needed size for the snapshot list.
*/
snaplistsize = fs->fs_ncg + howmany(fs->fs_cssize, fs->fs_bsize) +
FSMAXSNAP + 1 /* superblock */ + 1 /* last block */ + 1 /* size */;
MNT_ILOCK(mp);
loop:
/*
* NOTE: not using the TAILQ_FOREACH here since in this loop vgone()
* and vclean() can be called indirectly
*/
for (xvp = TAILQ_FIRST(&mp->mnt_vnodelist); xvp; xvp = nvp) {
/*
* Make sure this vnode wasn't reclaimed in getnewvnode().
* Start over if it has (it won't be on the list anymore).
*/
if (xvp->v_mount != mp)
goto loop;
VI_LOCK(xvp);
nvp = TAILQ_NEXT(xvp, v_mntvnodes);
MNT_IUNLOCK(mp);
if ((xvp->v_iflag & VI_XLOCK) ||
xvp->v_usecount == 0 || xvp->v_type == VNON ||
(VTOI(xvp)->i_flags & SF_SNAPSHOT)) {
VI_UNLOCK(xvp);
MNT_ILOCK(mp);
continue;
}
VI_UNLOCK(xvp);
#ifdef DEBUG
if (snapdebug)
vprint("ffs_snapshot: busy vnode", xvp);
#endif
if (VOP_GETATTR(xvp, &vat, l->l_cred) == 0 &&
vat.va_nlink > 0) {
MNT_ILOCK(mp);
continue;
}
xp = VTOI(xvp);
if (ffs_checkfreefile(copy_fs, vp, xp->i_number)) {
MNT_ILOCK(mp);
continue;
}
/*
* If there is a fragment, clear it here.
*/
blkno = 0;
loc = howmany(xp->i_size, fs->fs_bsize) - 1;
if (loc < NDADDR) {
len = fragroundup(fs, blkoff(fs, xp->i_size));
if (len > 0 && len < fs->fs_bsize) {
ffs_blkfree(copy_fs, vp, db_get(xp, loc),
len, xp->i_number);
blkno = db_get(xp, loc);
db_assign(xp, loc, 0);
}
}
snaplistsize += 1;
if (xp->i_ump->um_fstype == UFS1)
error = expunge_ufs1(vp, xp, copy_fs, fullacct_ufs1,
BLK_NOCOPY);
else
error = expunge_ufs2(vp, xp, copy_fs, fullacct_ufs2,
BLK_NOCOPY);
if (blkno)
db_assign(xp, loc, blkno);
if (!error)
error = ffs_freefile(copy_fs, vp, xp->i_number,
xp->i_mode);
if (error) {
free(copy_fs->fs_csp, M_UFSMNT);
goto out1;
}
MNT_ILOCK(mp);
}
MNT_IUNLOCK(mp);
/*
* If there already exist snapshots on this filesystem, grab a
* reference to their shared lock. If this is the first snapshot
* on this filesystem, we need to allocate a lock for the snapshots
* to share. In either case, acquire the snapshot lock and give
* up our original private lock.
*/
mutex_enter(&si->si_lock);
if ((xp = TAILQ_FIRST(&si->si_snapshots)) != NULL) {
VI_LOCK(vp);
vp->v_vnlock = ITOV(xp)->v_vnlock;
} else {
lockinit(&si->si_vnlock, PVFS, "snaplk", 0, LK_CANRECURSE);
VI_LOCK(vp);
vp->v_vnlock = &si->si_vnlock;
}
mutex_exit(&si->si_lock);
vn_lock(vp, LK_INTERLOCK | LK_EXCLUSIVE | LK_RETRY);
lockmgr(&vp->v_lock, LK_RELEASE, NULL);
/*
* If this is the first snapshot on this filesystem, then we need
* to allocate the space for the list of preallocated snapshot blocks.
* This list will be refined below, but this preliminary one will
* keep us out of deadlock until the full one is ready.
*/
if (xp == NULL) {
snapblklist = malloc(
snaplistsize * sizeof(ufs2_daddr_t), M_UFSMNT, M_WAITOK);
blkp = &snapblklist[1];
*blkp++ = lblkno(fs, fs->fs_sblockloc);
blkno = fragstoblks(fs, fs->fs_csaddr);
for (cg = 0; cg < fs->fs_ncg; cg++) {
if (fragstoblks(fs, cgtod(fs, cg)) > blkno)
break;
*blkp++ = fragstoblks(fs, cgtod(fs, cg));
}
len = howmany(fs->fs_cssize, fs->fs_bsize);
for (loc = 0; loc < len; loc++)
*blkp++ = blkno + loc;
for (; cg < fs->fs_ncg; cg++)
*blkp++ = fragstoblks(fs, cgtod(fs, cg));
snapblklist[0] = blkp - snapblklist;
mutex_enter(&si->si_lock);
if (si->si_snapblklist != NULL)
panic("ffs_snapshot: non-empty list");
si->si_snapblklist = snapblklist;
} else
mutex_enter(&si->si_lock);
/*
* Record snapshot inode. Since this is the newest snapshot,
* it must be placed at the end of the list.
*/
fs->fs_snapinum[snaploc] = ip->i_number;
if (ip->i_nextsnap.tqe_prev != 0)
panic("ffs_snapshot: %llu already on list",
(unsigned long long)ip->i_number);
TAILQ_INSERT_TAIL(&si->si_snapshots, ip, i_nextsnap);
if (xp == NULL)
fscow_establish(mp, ffs_copyonwrite, devvp);
si->si_gen++;
mutex_exit(&si->si_lock);
vp->v_vflag |= VV_SYSTEM;
out1:
/*
* Resume operation on filesystem.
*/
vfs_resume(vp->v_mount);
/*
* Set the mtime to the time the snapshot has been taken.
*/
TIMEVAL_TO_TIMESPEC(&starttime, &ts);
if (ctime)
*ctime = ts;
DIP_ASSIGN(ip, mtime, ts.tv_sec);
DIP_ASSIGN(ip, mtimensec, ts.tv_nsec);
ip->i_flag |= IN_CHANGE | IN_UPDATE;
#ifdef DEBUG
if (starttime.tv_sec > 0) {
getmicrotime(&endtime);
timersub(&endtime, &starttime, &endtime);
printf("%s: suspended %ld.%03ld sec, redo %ld of %d\n",
vp->v_mount->mnt_stat.f_mntonname, (long)endtime.tv_sec,
endtime.tv_usec / 1000, redo, fs->fs_ncg);
}
#endif
if (error)
goto out;
/*
* Copy allocation information from all the snapshots in
* this snapshot and then expunge them from its view.
*/
TAILQ_FOREACH(xp, &si->si_snapshots, i_nextsnap) {
if (xp == ip)
break;
if (xp->i_ump->um_fstype == UFS1)
error = expunge_ufs1(vp, xp, fs, snapacct_ufs1,
BLK_SNAP);
else
error = expunge_ufs2(vp, xp, fs, snapacct_ufs2,
BLK_SNAP);
if (error == 0 && xp->i_ffs_effnlink == 0)
error = ffs_freefile(copy_fs, vp,
xp->i_number, xp->i_mode);
if (error) {
fs->fs_snapinum[snaploc] = 0;
goto done;
}
}
/*
* Allocate space for the full list of preallocated snapshot blocks.
*/
snapblklist = malloc(snaplistsize * sizeof(ufs2_daddr_t),
M_UFSMNT, M_WAITOK);
ip->i_snapblklist = &snapblklist[1];
/*
* Expunge the blocks used by the snapshots from the set of
* blocks marked as used in the snapshot bitmaps. Also, collect
* the list of allocated blocks in i_snapblklist.
*/
if (ip->i_ump->um_fstype == UFS1)
error = expunge_ufs1(vp, ip, copy_fs, mapacct_ufs1, BLK_SNAP);
else
error = expunge_ufs2(vp, ip, copy_fs, mapacct_ufs2, BLK_SNAP);
if (error) {
fs->fs_snapinum[snaploc] = 0;
FREE(snapblklist, M_UFSMNT);
goto done;
}
if (snaplistsize < ip->i_snapblklist - snapblklist)
panic("ffs_snapshot: list too small");
snaplistsize = ip->i_snapblklist - snapblklist;
snapblklist[0] = snaplistsize;
ip->i_snapblklist = &snapblklist[0];
/*
* Write out the list of allocated blocks to the end of the snapshot.
*/
for (i = 0; i < snaplistsize; i++)
snapblklist[i] = ufs_rw64(snapblklist[i], ns);
error = vn_rdwr(UIO_WRITE, vp, (void *)snapblklist,
snaplistsize*sizeof(ufs2_daddr_t), lblktosize(fs, (off_t)numblks),
UIO_SYSSPACE, IO_NODELOCKED|IO_UNIT, l->l_cred, NULL, NULL);
for (i = 0; i < snaplistsize; i++)
snapblklist[i] = ufs_rw64(snapblklist[i], ns);
if (error) {
fs->fs_snapinum[snaploc] = 0;
FREE(snapblklist, M_UFSMNT);
goto done;
}
/*
* Write the superblock and its summary information
* to the snapshot.
*/
blkno = fragstoblks(fs, fs->fs_csaddr);
len = howmany(fs->fs_cssize, fs->fs_bsize);
space = copy_fs->fs_csp;
#ifdef FFS_EI
if (ns) {
ffs_sb_swap(copy_fs, copy_fs);
ffs_csum_swap(space, space, fs->fs_cssize);
}
#endif
for (loc = 0; loc < len; loc++) {
error = bread(vp, blkno + loc, fs->fs_bsize, KERNCRED, &nbp);
if (error) {
brelse(nbp, 0);
fs->fs_snapinum[snaploc] = 0;
FREE(snapblklist, M_UFSMNT);
goto done;
}
bcopy(space, nbp->b_data, fs->fs_bsize);
space = (char *)space + fs->fs_bsize;
bawrite(nbp);
}
/*
* As this is the newest list, it is the most inclusive, so
* should replace the previous list. If this is the first snapshot
* free the preliminary list.
*/
mutex_enter(&si->si_lock);
space = si->si_snapblklist;
si->si_snapblklist = snapblklist;
if (TAILQ_FIRST(&si->si_snapshots) == ip)
FREE(space, M_UFSMNT);
si->si_gen++;
mutex_exit(&si->si_lock);
done:
free(copy_fs->fs_csp, M_UFSMNT);
if (!error) {
error = bread(vp, lblkno(fs, fs->fs_sblockloc), fs->fs_bsize,
KERNCRED, &nbp);
if (error) {
brelse(nbp, 0);
fs->fs_snapinum[snaploc] = 0;
}
bcopy(sbbuf, nbp->b_data, fs->fs_bsize);
bawrite(nbp);
}
out:
/*
* Invalidate and free all pages on the snapshot vnode.
* All metadata has been written through the buffer cache.
* Clean all dirty buffers now to avoid UBC inconsistencies.
*/
if (!error) {
simple_lock(&vp->v_interlock);
error = VOP_PUTPAGES(vp, 0, 0,
PGO_ALLPAGES|PGO_CLEANIT|PGO_SYNCIO|PGO_FREE);
}
if (!error) {
s = splbio();
for (bp = LIST_FIRST(&vp->v_dirtyblkhd); bp; bp = nbp) {
nbp = LIST_NEXT(bp, b_vnbufs);
simple_lock(&bp->b_interlock);
splx(s);
if ((bp->b_flags & (B_DELWRI|B_BUSY)) != B_DELWRI)
panic("ffs_snapshot: not dirty or busy, bp %p",
bp);
bp->b_flags |= B_BUSY|B_VFLUSH;
if (LIST_FIRST(&bp->b_dep) == NULL)
bp->b_flags |= B_NOCACHE;
simple_unlock(&bp->b_interlock);
bwrite(bp);
s = splbio();
}
simple_lock(&global_v_numoutput_slock);
while (vp->v_numoutput) {
vp->v_iflag |= VI_BWAIT;
ltsleep((void *)&vp->v_numoutput, PRIBIO+1,
"snapflushbuf", 0, &global_v_numoutput_slock);
}
simple_unlock(&global_v_numoutput_slock);
splx(s);
}
if (sbbuf)
free(sbbuf, M_UFSMNT);
if (fs->fs_active != 0) {
FREE(fs->fs_active, M_DEVBUF);
fs->fs_active = 0;
}
mp->mnt_flag = flag;
if (error)
(void) ffs_truncate(vp, (off_t)0, 0, NOCRED, l);
else
vref(vp);
return (error);
}
/*
* Copy a cylinder group map. All the unallocated blocks are marked
* BLK_NOCOPY so that the snapshot knows that it need not copy them
* if they are later written. If passno is one, then this is a first
* pass, so only setting needs to be done. If passno is 2, then this
* is a revision to a previous pass which must be undone as the
* replacement pass is done.
*/
static int
cgaccount(int cg, struct vnode *vp, void *data, int passno)
{
struct buf *bp, *ibp;
struct inode *ip;
struct cg *cgp;
struct fs *fs;
ufs2_daddr_t base, numblks;
int error, len, loc, ns, indiroff;
ip = VTOI(vp);
fs = ip->i_fs;
ns = UFS_FSNEEDSWAP(fs);
error = bread(ip->i_devvp, fsbtodb(fs, cgtod(fs, cg)),
(int)fs->fs_cgsize, KERNCRED, &bp);
if (error) {
brelse(bp, 0);
return (error);
}
cgp = (struct cg *)bp->b_data;
if (!cg_chkmagic(cgp, ns)) {
brelse(bp, 0);
return (EIO);
}
ACTIVECG_SET(fs, cg);
bcopy(bp->b_data, data, fs->fs_cgsize);
brelse(bp, 0);
if (fs->fs_cgsize < fs->fs_bsize)
memset((char *)data + fs->fs_cgsize, 0,
fs->fs_bsize - fs->fs_cgsize);
numblks = howmany(fs->fs_size, fs->fs_frag);
len = howmany(fs->fs_fpg, fs->fs_frag);
base = cg * fs->fs_fpg / fs->fs_frag;
if (base + len >= numblks)
len = numblks - base - 1;
loc = 0;
if (base < NDADDR) {
for ( ; loc < NDADDR; loc++) {
if (ffs_isblock(fs, cg_blksfree(cgp, ns), loc))
db_assign(ip, loc, BLK_NOCOPY);
else if (db_get(ip, loc) == BLK_NOCOPY) {
if (passno == 2)
db_assign(ip, loc, 0);
else if (passno == 1)
panic("ffs_snapshot: lost direct block");
}
}
}
if ((error = ffs_balloc(vp, lblktosize(fs, (off_t)(base + loc)),
fs->fs_bsize, KERNCRED, B_METAONLY, &ibp)) != 0)
return (error);
indiroff = (base + loc - NDADDR) % NINDIR(fs);
for ( ; loc < len; loc++, indiroff++) {
if (indiroff >= NINDIR(fs)) {
bawrite(ibp);
if ((error = ffs_balloc(vp,
lblktosize(fs, (off_t)(base + loc)),
fs->fs_bsize, KERNCRED, B_METAONLY, &ibp)) != 0)
return (error);
indiroff = 0;
}
if (ffs_isblock(fs, cg_blksfree(cgp, ns), loc))
idb_assign(ip, ibp->b_data, indiroff, BLK_NOCOPY);
else if (idb_get(ip, ibp->b_data, indiroff) == BLK_NOCOPY) {
if (passno == 2)
idb_assign(ip, ibp->b_data, indiroff, 0);
else if (passno == 1)
panic("ffs_snapshot: lost indirect block");
}
}
bdwrite(ibp);
return (0);
}
/*
* Before expunging a snapshot inode, note all the
* blocks that it claims with BLK_SNAP so that fsck will
* be able to account for those blocks properly and so
* that this snapshot knows that it need not copy them
* if the other snapshot holding them is freed. This code
* is reproduced once each for UFS1 and UFS2.
*/
static int
expunge_ufs1(struct vnode *snapvp, struct inode *cancelip, struct fs *fs,
int (*acctfunc)(struct vnode *, ufs1_daddr_t *, ufs1_daddr_t *,
struct fs *, ufs_lbn_t, int),
int expungetype)
{
int i, s, error, ns, indiroff;
ufs_lbn_t lbn, rlbn;
ufs2_daddr_t len, blkno, numblks, blksperindir;
struct ufs1_dinode *dip;
struct buf *bp;
void *bf;
ns = UFS_FSNEEDSWAP(fs);
/*
* Prepare to expunge the inode. If its inode block has not
* yet been copied, then allocate and fill the copy.
*/
lbn = fragstoblks(fs, ino_to_fsba(fs, cancelip->i_number));
blkno = 0;
if (lbn < NDADDR) {
blkno = db_get(VTOI(snapvp), lbn);
} else {
s = cow_enter();
error = ffs_balloc(snapvp, lblktosize(fs, (off_t)lbn),
fs->fs_bsize, KERNCRED, B_METAONLY, &bp);
cow_leave(s);
if (error)
return (error);
indiroff = (lbn - NDADDR) % NINDIR(fs);
blkno = idb_get(VTOI(snapvp), bp->b_data, indiroff);
brelse(bp, 0);
}
bf = malloc(fs->fs_bsize, M_UFSMNT, M_WAITOK);
if (blkno != 0)
error = readvnblk(snapvp, bf, lbn);
else
error = readfsblk(snapvp, bf, lbn);
if (error) {
free(bf, M_UFSMNT);
return error;
}
/*
* Set a snapshot inode to be a zero length file, regular files
* or unlinked snapshots to be completely unallocated.
*/
dip = (struct ufs1_dinode *)bf + ino_to_fsbo(fs, cancelip->i_number);
if (expungetype == BLK_NOCOPY || cancelip->i_ffs_effnlink == 0)
dip->di_mode = 0;
dip->di_size = 0;
dip->di_blocks = 0;
dip->di_flags =
ufs_rw32(ufs_rw32(dip->di_flags, ns) & ~SF_SNAPSHOT, ns);
bzero(&dip->di_db[0], (NDADDR + NIADDR) * sizeof(ufs1_daddr_t));
error = writevnblk(snapvp, bf, lbn);
free(bf, M_UFSMNT);
if (error)
return error;
/*
* Now go through and expunge all the blocks in the file
* using the function requested.
*/
numblks = howmany(cancelip->i_size, fs->fs_bsize);
if ((error = (*acctfunc)(snapvp, &cancelip->i_ffs1_db[0],
&cancelip->i_ffs1_db[NDADDR], fs, 0, expungetype)))
return (error);
if ((error = (*acctfunc)(snapvp, &cancelip->i_ffs1_ib[0],
&cancelip->i_ffs1_ib[NIADDR], fs, -1, expungetype)))
return (error);
blksperindir = 1;
lbn = -NDADDR;
len = numblks - NDADDR;
rlbn = NDADDR;
for (i = 0; len > 0 && i < NIADDR; i++) {
error = indiracct_ufs1(snapvp, ITOV(cancelip), i,
ufs_rw32(cancelip->i_ffs1_ib[i], ns), lbn, rlbn, len,
blksperindir, fs, acctfunc, expungetype);
if (error)
return (error);
blksperindir *= NINDIR(fs);
lbn -= blksperindir + 1;
len -= blksperindir;
rlbn += blksperindir;
}
return (0);
}
/*
* Descend an indirect block chain for vnode cancelvp accounting for all
* its indirect blocks in snapvp.
*/
static int
indiracct_ufs1(struct vnode *snapvp, struct vnode *cancelvp, int level,
ufs1_daddr_t blkno, ufs_lbn_t lbn, ufs_lbn_t rlbn, ufs_lbn_t remblks,
ufs_lbn_t blksperindir, struct fs *fs,
int (*acctfunc)(struct vnode *, ufs1_daddr_t *, ufs1_daddr_t *,
struct fs *, ufs_lbn_t, int),
int expungetype)
{
int error, ns, num, i;
ufs_lbn_t subblksperindir;
struct indir indirs[NIADDR + 2];
ufs1_daddr_t last, *bap;
struct buf *bp;
ns = UFS_FSNEEDSWAP(fs);
if (blkno == 0) {
if (expungetype == BLK_NOCOPY)
return (0);
panic("indiracct_ufs1: missing indir");
}
if ((error = ufs_getlbns(cancelvp, rlbn, indirs, &num)) != 0)
return (error);
if (lbn != indirs[num - 1 - level].in_lbn || num < 2)
panic("indiracct_ufs1: botched params");
/*
* We have to expand bread here since it will deadlock looking
* up the block number for any blocks that are not in the cache.
*/
bp = getblk(cancelvp, lbn, fs->fs_bsize, 0, 0);
bp->b_blkno = fsbtodb(fs, blkno);
if ((bp->b_flags & (B_DONE | B_DELWRI)) == 0 &&
(error = readfsblk(bp->b_vp, bp->b_data, fragstoblks(fs, blkno)))) {
brelse(bp, 0);
return (error);
}
/*
* Account for the block pointers in this indirect block.
*/
last = howmany(remblks, blksperindir);
if (last > NINDIR(fs))
last = NINDIR(fs);
bap = malloc(fs->fs_bsize, M_DEVBUF, M_WAITOK);
bcopy(bp->b_data, (void *)bap, fs->fs_bsize);
brelse(bp, 0);
error = (*acctfunc)(snapvp, &bap[0], &bap[last], fs,
level == 0 ? rlbn : -1, expungetype);
if (error || level == 0)
goto out;
/*
* Account for the block pointers in each of the indirect blocks
* in the levels below us.
*/
subblksperindir = blksperindir / NINDIR(fs);
for (lbn++, level--, i = 0; i < last; i++) {
error = indiracct_ufs1(snapvp, cancelvp, level,
ufs_rw32(bap[i], ns), lbn, rlbn, remblks, subblksperindir,
fs, acctfunc, expungetype);
if (error)
goto out;
rlbn += blksperindir;
lbn -= blksperindir;
remblks -= blksperindir;
}
out:
FREE(bap, M_DEVBUF);
return (error);
}
/*
* Do both snap accounting and map accounting.
*/
static int
fullacct_ufs1(struct vnode *vp, ufs1_daddr_t *oldblkp, ufs1_daddr_t *lastblkp,
struct fs *fs, ufs_lbn_t lblkno,
int exptype /* BLK_SNAP or BLK_NOCOPY */)
{
int error;
if ((error = snapacct_ufs1(vp, oldblkp, lastblkp, fs, lblkno, exptype)))
return (error);
return (mapacct_ufs1(vp, oldblkp, lastblkp, fs, lblkno, exptype));
}
/*
* Identify a set of blocks allocated in a snapshot inode.
*/
static int
snapacct_ufs1(struct vnode *vp, ufs1_daddr_t *oldblkp, ufs1_daddr_t *lastblkp,
struct fs *fs, ufs_lbn_t lblkno,
int expungetype /* BLK_SNAP or BLK_NOCOPY */)
{
struct inode *ip = VTOI(vp);
ufs1_daddr_t blkno, *blkp;
ufs_lbn_t lbn;
struct buf *ibp;
int error, ns;
ns = UFS_FSNEEDSWAP(fs);
for ( ; oldblkp < lastblkp; oldblkp++) {
blkno = ufs_rw32(*oldblkp, ns);
if (blkno == 0 || blkno == BLK_NOCOPY || blkno == BLK_SNAP)
continue;
lbn = fragstoblks(fs, blkno);
if (lbn < NDADDR) {
blkp = &ip->i_ffs1_db[lbn];
ip->i_flag |= IN_CHANGE | IN_UPDATE;
} else {
error = ffs_balloc(vp, lblktosize(fs, (off_t)lbn),
fs->fs_bsize, KERNCRED, B_METAONLY, &ibp);
if (error)
return (error);
blkp = &((ufs1_daddr_t *)(ibp->b_data))
[(lbn - NDADDR) % NINDIR(fs)];
}
/*
* If we are expunging a snapshot vnode and we
* find a block marked BLK_NOCOPY, then it is
* one that has been allocated to this snapshot after
* we took our current snapshot and can be ignored.
*/
blkno = ufs_rw32(*blkp, ns);
if (expungetype == BLK_SNAP && blkno == BLK_NOCOPY) {
if (lbn >= NDADDR)
brelse(ibp, 0);
} else {
if (blkno != 0)
panic("snapacct_ufs1: bad block");
*blkp = ufs_rw32(expungetype, ns);
if (lbn >= NDADDR)
bdwrite(ibp);
}
}
return (0);
}
/*
* Account for a set of blocks allocated in a snapshot inode.
*/
static int
mapacct_ufs1(struct vnode *vp, ufs1_daddr_t *oldblkp, ufs1_daddr_t *lastblkp,
struct fs *fs, ufs_lbn_t lblkno, int expungetype)
{
ufs1_daddr_t blkno;
struct inode *ip;
ino_t inum;
int acctit, ns;
ns = UFS_FSNEEDSWAP(fs);
ip = VTOI(vp);
inum = ip->i_number;
if (lblkno == -1)
acctit = 0;
else
acctit = 1;
for ( ; oldblkp < lastblkp; oldblkp++, lblkno++) {
blkno = ufs_rw32(*oldblkp, ns);
if (blkno == 0 || blkno == BLK_NOCOPY)
continue;
if (acctit && expungetype == BLK_SNAP && blkno != BLK_SNAP)
*ip->i_snapblklist++ = lblkno;
if (blkno == BLK_SNAP)
blkno = blkstofrags(fs, lblkno);
ffs_blkfree(fs, vp, blkno, fs->fs_bsize, inum);
}
return (0);
}
/*
* Before expunging a snapshot inode, note all the
* blocks that it claims with BLK_SNAP so that fsck will
* be able to account for those blocks properly and so
* that this snapshot knows that it need not copy them
* if the other snapshot holding them is freed. This code
* is reproduced once each for UFS1 and UFS2.
*/
static int
expunge_ufs2(struct vnode *snapvp, struct inode *cancelip, struct fs *fs,
int (*acctfunc)(struct vnode *, ufs2_daddr_t *, ufs2_daddr_t *,
struct fs *, ufs_lbn_t, int),
int expungetype)
{
int i, s, error, ns, indiroff;
ufs_lbn_t lbn, rlbn;
ufs2_daddr_t len, blkno, numblks, blksperindir;
struct ufs2_dinode *dip;
struct buf *bp;
void *bf;
ns = UFS_FSNEEDSWAP(fs);
/*
* Prepare to expunge the inode. If its inode block has not
* yet been copied, then allocate and fill the copy.
*/
lbn = fragstoblks(fs, ino_to_fsba(fs, cancelip->i_number));
blkno = 0;
if (lbn < NDADDR) {
blkno = db_get(VTOI(snapvp), lbn);
} else {
s = cow_enter();
error = ffs_balloc(snapvp, lblktosize(fs, (off_t)lbn),
fs->fs_bsize, KERNCRED, B_METAONLY, &bp);
cow_leave(s);
if (error)
return (error);
indiroff = (lbn - NDADDR) % NINDIR(fs);
blkno = idb_get(VTOI(snapvp), bp->b_data, indiroff);
brelse(bp, 0);
}
bf = malloc(fs->fs_bsize, M_UFSMNT, M_WAITOK);
if (blkno != 0)
error = readvnblk(snapvp, bf, lbn);
else
error = readfsblk(snapvp, bf, lbn);
if (error) {
free(bf, M_UFSMNT);
return error;
}
/*
* Set a snapshot inode to be a zero length file, regular files
* or unlinked snapshots to be completely unallocated.
*/
dip = (struct ufs2_dinode *)bf + ino_to_fsbo(fs, cancelip->i_number);
if (expungetype == BLK_NOCOPY || cancelip->i_ffs_effnlink == 0)
dip->di_mode = 0;
dip->di_size = 0;
dip->di_blocks = 0;
dip->di_flags =
ufs_rw32(ufs_rw32(dip->di_flags, ns) & ~SF_SNAPSHOT, ns);
bzero(&dip->di_db[0], (NDADDR + NIADDR) * sizeof(ufs2_daddr_t));
error = writevnblk(snapvp, bf, lbn);
free(bf, M_UFSMNT);
if (error)
return error;
/*
* Now go through and expunge all the blocks in the file
* using the function requested.
*/
numblks = howmany(cancelip->i_size, fs->fs_bsize);
if ((error = (*acctfunc)(snapvp, &cancelip->i_ffs2_db[0],
&cancelip->i_ffs2_db[NDADDR], fs, 0, expungetype)))
return (error);
if ((error = (*acctfunc)(snapvp, &cancelip->i_ffs2_ib[0],
&cancelip->i_ffs2_ib[NIADDR], fs, -1, expungetype)))
return (error);
blksperindir = 1;
lbn = -NDADDR;
len = numblks - NDADDR;
rlbn = NDADDR;
for (i = 0; len > 0 && i < NIADDR; i++) {
error = indiracct_ufs2(snapvp, ITOV(cancelip), i,
ufs_rw64(cancelip->i_ffs2_ib[i], ns), lbn, rlbn, len,
blksperindir, fs, acctfunc, expungetype);
if (error)
return (error);
blksperindir *= NINDIR(fs);
lbn -= blksperindir + 1;
len -= blksperindir;
rlbn += blksperindir;
}
return (0);
}
/*
* Descend an indirect block chain for vnode cancelvp accounting for all
* its indirect blocks in snapvp.
*/
static int
indiracct_ufs2(struct vnode *snapvp, struct vnode *cancelvp, int level,
ufs2_daddr_t blkno, ufs_lbn_t lbn, ufs_lbn_t rlbn, ufs_lbn_t remblks,
ufs_lbn_t blksperindir, struct fs *fs,
int (*acctfunc)(struct vnode *, ufs2_daddr_t *, ufs2_daddr_t *,
struct fs *, ufs_lbn_t, int),
int expungetype)
{
int error, ns, num, i;
ufs_lbn_t subblksperindir;
struct indir indirs[NIADDR + 2];
ufs2_daddr_t last, *bap;
struct buf *bp;
ns = UFS_FSNEEDSWAP(fs);
if (blkno == 0) {
if (expungetype == BLK_NOCOPY)
return (0);
panic("indiracct_ufs2: missing indir");
}
if ((error = ufs_getlbns(cancelvp, rlbn, indirs, &num)) != 0)
return (error);
if (lbn != indirs[num - 1 - level].in_lbn || num < 2)
panic("indiracct_ufs2: botched params");
/*
* We have to expand bread here since it will deadlock looking
* up the block number for any blocks that are not in the cache.
*/
bp = getblk(cancelvp, lbn, fs->fs_bsize, 0, 0);
bp->b_blkno = fsbtodb(fs, blkno);
if ((bp->b_flags & (B_DONE | B_DELWRI)) == 0 &&
(error = readfsblk(bp->b_vp, bp->b_data, fragstoblks(fs, blkno)))) {
brelse(bp, 0);
return (error);
}
/*
* Account for the block pointers in this indirect block.
*/
last = howmany(remblks, blksperindir);
if (last > NINDIR(fs))
last = NINDIR(fs);
bap = malloc(fs->fs_bsize, M_DEVBUF, M_WAITOK);
bcopy(bp->b_data, (void *)bap, fs->fs_bsize);
brelse(bp, 0);
error = (*acctfunc)(snapvp, &bap[0], &bap[last], fs,
level == 0 ? rlbn : -1, expungetype);
if (error || level == 0)
goto out;
/*
* Account for the block pointers in each of the indirect blocks
* in the levels below us.
*/
subblksperindir = blksperindir / NINDIR(fs);
for (lbn++, level--, i = 0; i < last; i++) {
error = indiracct_ufs2(snapvp, cancelvp, level,
ufs_rw64(bap[i], ns), lbn, rlbn, remblks, subblksperindir,
fs, acctfunc, expungetype);
if (error)
goto out;
rlbn += blksperindir;
lbn -= blksperindir;
remblks -= blksperindir;
}
out:
FREE(bap, M_DEVBUF);
return (error);
}
/*
* Do both snap accounting and map accounting.
*/
static int
fullacct_ufs2(struct vnode *vp, ufs2_daddr_t *oldblkp, ufs2_daddr_t *lastblkp,
struct fs *fs, ufs_lbn_t lblkno,
int exptype /* BLK_SNAP or BLK_NOCOPY */)
{
int error;
if ((error = snapacct_ufs2(vp, oldblkp, lastblkp, fs, lblkno, exptype)))
return (error);
return (mapacct_ufs2(vp, oldblkp, lastblkp, fs, lblkno, exptype));
}
/*
* Identify a set of blocks allocated in a snapshot inode.
*/
static int
snapacct_ufs2(struct vnode *vp, ufs2_daddr_t *oldblkp, ufs2_daddr_t *lastblkp,
struct fs *fs, ufs_lbn_t lblkno,
int expungetype /* BLK_SNAP or BLK_NOCOPY */)
{
struct inode *ip = VTOI(vp);
ufs2_daddr_t blkno, *blkp;
ufs_lbn_t lbn;
struct buf *ibp;
int error, ns;
ns = UFS_FSNEEDSWAP(fs);
for ( ; oldblkp < lastblkp; oldblkp++) {
blkno = ufs_rw64(*oldblkp, ns);
if (blkno == 0 || blkno == BLK_NOCOPY || blkno == BLK_SNAP)
continue;
lbn = fragstoblks(fs, blkno);
if (lbn < NDADDR) {
blkp = &ip->i_ffs2_db[lbn];
ip->i_flag |= IN_CHANGE | IN_UPDATE;
} else {
error = ffs_balloc(vp, lblktosize(fs, (off_t)lbn),
fs->fs_bsize, KERNCRED, B_METAONLY, &ibp);
if (error)
return (error);
blkp = &((ufs2_daddr_t *)(ibp->b_data))
[(lbn - NDADDR) % NINDIR(fs)];
}
/*
* If we are expunging a snapshot vnode and we
* find a block marked BLK_NOCOPY, then it is
* one that has been allocated to this snapshot after
* we took our current snapshot and can be ignored.
*/
blkno = ufs_rw64(*blkp, ns);
if (expungetype == BLK_SNAP && blkno == BLK_NOCOPY) {
if (lbn >= NDADDR)
brelse(ibp, 0);
} else {
if (blkno != 0)
panic("snapacct_ufs2: bad block");
*blkp = ufs_rw64(expungetype, ns);
if (lbn >= NDADDR)
bdwrite(ibp);
}
}
return (0);
}
/*
* Account for a set of blocks allocated in a snapshot inode.
*/
static int
mapacct_ufs2(struct vnode *vp, ufs2_daddr_t *oldblkp, ufs2_daddr_t *lastblkp,
struct fs *fs, ufs_lbn_t lblkno, int expungetype)
{
ufs2_daddr_t blkno;
struct inode *ip;
ino_t inum;
int acctit, ns;
ns = UFS_FSNEEDSWAP(fs);
ip = VTOI(vp);
inum = ip->i_number;
if (lblkno == -1)
acctit = 0;
else
acctit = 1;
for ( ; oldblkp < lastblkp; oldblkp++, lblkno++) {
blkno = ufs_rw64(*oldblkp, ns);
if (blkno == 0 || blkno == BLK_NOCOPY)
continue;
if (acctit && expungetype == BLK_SNAP && blkno != BLK_SNAP)
*ip->i_snapblklist++ = lblkno;
if (blkno == BLK_SNAP)
blkno = blkstofrags(fs, lblkno);
ffs_blkfree(fs, vp, blkno, fs->fs_bsize, inum);
}
return (0);
}
#endif /* defined(FFS_NO_SNAPSHOT) */
/*
* Decrement extra reference on snapshot when last name is removed.
* It will not be freed until the last open reference goes away.
*/
void
ffs_snapgone(struct inode *ip)
{
struct mount *mp = ip->i_devvp->v_specmountpoint;
struct inode *xp;
struct fs *fs;
struct snap_info *si;
int snaploc;
if ((si = mount_getspecific(mp, si_mount_data_key)) == NULL)
return;
/*
* Find snapshot in incore list.
*/
mutex_enter(&si->si_lock);
TAILQ_FOREACH(xp, &si->si_snapshots, i_nextsnap)
if (xp == ip)
break;
mutex_exit(&si->si_lock);
if (xp != NULL)
vrele(ITOV(ip));
#ifdef DEBUG
else if (snapdebug)
printf("ffs_snapgone: lost snapshot vnode %llu\n",
(unsigned long long)ip->i_number);
#endif
/*
* Delete snapshot inode from superblock. Keep list dense.
*/
mutex_enter(&si->si_lock);
fs = ip->i_fs;
for (snaploc = 0; snaploc < FSMAXSNAP; snaploc++)
if (fs->fs_snapinum[snaploc] == ip->i_number)
break;
if (snaploc < FSMAXSNAP) {
for (snaploc++; snaploc < FSMAXSNAP; snaploc++) {
if (fs->fs_snapinum[snaploc] == 0)
break;
fs->fs_snapinum[snaploc - 1] = fs->fs_snapinum[snaploc];
}
fs->fs_snapinum[snaploc - 1] = 0;
}
si->si_gen++;
mutex_exit(&si->si_lock);
}
/*
* Prepare a snapshot file for being removed.
*/
void
ffs_snapremove(struct vnode *vp)
{
struct inode *ip = VTOI(vp), *xp;
struct vnode *devvp = ip->i_devvp;
struct fs *fs = ip->i_fs;
struct mount *mp = devvp->v_specmountpoint;
struct lock *lkp;
struct buf *ibp;
struct snap_info *si;
ufs2_daddr_t numblks, blkno, dblk;
int error, ns, loc, last;
if ((si = mount_getspecific(mp, si_mount_data_key)) == NULL)
return;
ns = UFS_FSNEEDSWAP(fs);
/*
* If active, delete from incore list (this snapshot may
* already have been in the process of being deleted, so
* would not have been active).
*
* Clear copy-on-write flag if last snapshot.
*/
if (ip->i_nextsnap.tqe_prev != 0) {
mutex_enter(&si->si_lock);
lockmgr(&vp->v_lock, LK_EXCLUSIVE, NULL);
TAILQ_REMOVE(&si->si_snapshots, ip, i_nextsnap);
ip->i_nextsnap.tqe_prev = 0;
VI_LOCK(vp);
lkp = vp->v_vnlock;
vp->v_vnlock = &vp->v_lock;
lockmgr(lkp, LK_RELEASE | LK_INTERLOCK, VI_MTX(vp));
if (TAILQ_FIRST(&si->si_snapshots) != 0) {
/* Roll back the list of preallocated blocks. */
xp = TAILQ_LAST(&si->si_snapshots, inodelst);
si->si_snapblklist = xp->i_snapblklist;
} else {
si->si_snapblklist = 0;
si->si_gen++;
mutex_exit(&si->si_lock);
lockmgr(lkp, LK_DRAIN, NULL);
lockmgr(lkp, LK_RELEASE, NULL);
fscow_disestablish(mp, ffs_copyonwrite, devvp);
mutex_enter(&si->si_lock);
}
si->si_gen++;
mutex_exit(&si->si_lock);
FREE(ip->i_snapblklist, M_UFSMNT);
ip->i_snapblklist = NULL;
}
/*
* Clear all BLK_NOCOPY fields. Pass any block claims to other
* snapshots that want them (see ffs_snapblkfree below).
*/
for (blkno = 1; blkno < NDADDR; blkno++) {
dblk = db_get(ip, blkno);
if (dblk == BLK_NOCOPY || dblk == BLK_SNAP)
db_assign(ip, blkno, 0);
else if ((dblk == blkstofrags(fs, blkno) &&
ffs_snapblkfree(fs, ip->i_devvp, dblk, fs->fs_bsize,
ip->i_number))) {
DIP_ADD(ip, blocks, -btodb(fs->fs_bsize));
db_assign(ip, blkno, 0);
}
}
numblks = howmany(ip->i_size, fs->fs_bsize);
for (blkno = NDADDR; blkno < numblks; blkno += NINDIR(fs)) {
error = ffs_balloc(vp, lblktosize(fs, (off_t)blkno),
fs->fs_bsize, KERNCRED, B_METAONLY, &ibp);
if (error)
continue;
if (fs->fs_size - blkno > NINDIR(fs))
last = NINDIR(fs);
else
last = fs->fs_size - blkno;
for (loc = 0; loc < last; loc++) {
dblk = idb_get(ip, ibp->b_data, loc);
if (dblk == BLK_NOCOPY || dblk == BLK_SNAP)
idb_assign(ip, ibp->b_data, loc, 0);
else if (dblk == blkstofrags(fs, blkno) &&
ffs_snapblkfree(fs, ip->i_devvp, dblk,
fs->fs_bsize, ip->i_number)) {
DIP_ADD(ip, blocks, -btodb(fs->fs_bsize));
idb_assign(ip, ibp->b_data, loc, 0);
}
}
bawrite(ibp);
}
/*
* Clear snapshot flag and drop reference.
*/
ip->i_flags &= ~SF_SNAPSHOT;
DIP_ASSIGN(ip, flags, ip->i_flags);
ip->i_flag |= IN_CHANGE | IN_UPDATE;
}
/*
* Notification that a block is being freed. Return zero if the free
* should be allowed to proceed. Return non-zero if the snapshot file
* wants to claim the block. The block will be claimed if it is an
* uncopied part of one of the snapshots. It will be freed if it is
* either a BLK_NOCOPY or has already been copied in all of the snapshots.
* If a fragment is being freed, then all snapshots that care about
* it must make a copy since a snapshot file can only claim full sized
* blocks. Note that if more than one snapshot file maps the block,
* we can pick one at random to claim it. Since none of the snapshots
* can change, we are assurred that they will all see the same unmodified
* image. When deleting a snapshot file (see ffs_snapremove above), we
* must push any of these claimed blocks to one of the other snapshots
* that maps it. These claimed blocks are easily identified as they will
* have a block number equal to their logical block number within the
* snapshot. A copied block can never have this property because they
* must always have been allocated from a BLK_NOCOPY location.
*/
int
ffs_snapblkfree(struct fs *fs, struct vnode *devvp, ufs2_daddr_t bno,
long size, ino_t inum)
{
struct mount *mp = devvp->v_specmountpoint;
struct buf *ibp;
struct inode *ip;
struct vnode *vp = NULL;
struct snap_info *si;
void *saved_data = NULL;
ufs_lbn_t lbn;
ufs2_daddr_t blkno;
uint32_t gen;
int s, indiroff = 0, snapshot_locked = 0, error = 0, claimedblk = 0;
if ((si = mount_getspecific(mp, si_mount_data_key)) == NULL)
return 0;
lbn = fragstoblks(fs, bno);
mutex_enter(&si->si_lock);
retry:
gen = si->si_gen;
TAILQ_FOREACH(ip, &si->si_snapshots, i_nextsnap) {
vp = ITOV(ip);
if (snapshot_locked == 0) {
mutex_exit(&si->si_lock);
if (VOP_LOCK(vp, LK_EXCLUSIVE | LK_SLEEPFAIL) != 0) {
mutex_enter(&si->si_lock);
goto retry;
}
mutex_enter(&si->si_lock);
snapshot_locked = 1;
if (gen != si->si_gen)
goto retry;
}
/*
* Lookup block being written.
*/
if (lbn < NDADDR) {
blkno = db_get(ip, lbn);
} else {
mutex_exit(&si->si_lock);
s = cow_enter();
error = ffs_balloc(vp, lblktosize(fs, (off_t)lbn),
fs->fs_bsize, KERNCRED, B_METAONLY, &ibp);
cow_leave(s);
if (error) {
mutex_enter(&si->si_lock);
break;
}
indiroff = (lbn - NDADDR) % NINDIR(fs);
blkno = idb_get(ip, ibp->b_data, indiroff);
mutex_enter(&si->si_lock);
if (gen != si->si_gen) {
brelse(ibp, 0);
goto retry;
}
}
/*
* Check to see if block needs to be copied.
*/
if (blkno == 0) {
/*
* A block that we map is being freed. If it has not
* been claimed yet, we will claim or copy it (below).
*/
claimedblk = 1;
} else if (blkno == BLK_SNAP) {
/*
* No previous snapshot claimed the block,
* so it will be freed and become a BLK_NOCOPY
* (don't care) for us.
*/
if (claimedblk)
panic("snapblkfree: inconsistent block type");
if (lbn < NDADDR) {
db_assign(ip, lbn, BLK_NOCOPY);
ip->i_flag |= IN_CHANGE | IN_UPDATE;
} else {
idb_assign(ip, ibp->b_data, indiroff,
BLK_NOCOPY);
mutex_exit(&si->si_lock);
bwrite(ibp);
mutex_enter(&si->si_lock);
if (gen != si->si_gen)
goto retry;
}
continue;
} else /* BLK_NOCOPY or default */ {
/*
* If the snapshot has already copied the block
* (default), or does not care about the block,
* it is not needed.
*/
if (lbn >= NDADDR)
brelse(ibp, 0);
continue;
}
/*
* If this is a full size block, we will just grab it
* and assign it to the snapshot inode. Otherwise we
* will proceed to copy it. See explanation for this
* routine as to why only a single snapshot needs to
* claim this block.
*/
if (size == fs->fs_bsize) {
#ifdef DEBUG
if (snapdebug)
printf("%s %llu lbn %" PRId64
"from inum %llu\n",
"Grabonremove: snapino",
(unsigned long long)ip->i_number,
lbn, (unsigned long long)inum);
#endif
mutex_exit(&si->si_lock);
if (lbn < NDADDR) {
db_assign(ip, lbn, bno);
} else {
idb_assign(ip, ibp->b_data, indiroff, bno);
bwrite(ibp);
}
DIP_ADD(ip, blocks, btodb(size));
ip->i_flag |= IN_CHANGE | IN_UPDATE;
VOP_UNLOCK(vp, 0);
return (1);
}
if (lbn >= NDADDR)
brelse(ibp, 0);
#ifdef DEBUG
if (snapdebug)
printf("%s%llu lbn %" PRId64 " %s %llu size %ld\n",
"Copyonremove: snapino ",
(unsigned long long)ip->i_number,
lbn, "for inum", (unsigned long long)inum, size);
#endif
/*
* If we have already read the old block contents, then
* simply copy them to the new block. Note that we need
* to synchronously write snapshots that have not been
* unlinked, and hence will be visible after a crash,
* to ensure their integrity.
*/
mutex_exit(&si->si_lock);
if (saved_data == NULL) {
saved_data = malloc(fs->fs_bsize, M_UFSMNT, M_WAITOK);
if ((error = readfsblk(vp, saved_data, lbn)) != 0) {
free(saved_data, M_UFSMNT);
saved_data = NULL;
mutex_enter(&si->si_lock);
break;
}
}
error = writevnblk(vp, saved_data, lbn);
mutex_enter(&si->si_lock);
if (error)
break;
if (gen != si->si_gen)
goto retry;
}
mutex_exit(&si->si_lock);
if (saved_data)
free(saved_data, M_UFSMNT);
/*
* If we have been unable to allocate a block in which to do
* the copy, then return non-zero so that the fragment will
* not be freed. Although space will be lost, the snapshot
* will stay consistent.
*/
if (snapshot_locked)
VOP_UNLOCK(vp, 0);
return (error);
}
/*
* Associate snapshot files when mounting.
*/
void
ffs_snapshot_mount(struct mount *mp)
{
struct vnode *devvp = VFSTOUFS(mp)->um_devvp;
struct fs *fs = VFSTOUFS(mp)->um_fs;
struct lwp *l = curlwp;
struct vnode *vp;
struct inode *ip, *xp;
struct snap_info *si;
ufs2_daddr_t snaplistsize, *snapblklist;
int i, error, ns, snaploc, loc;
/*
* No persistent snapshots on apple ufs file systems.
*/
if (UFS_MPISAPPLEUFS(VFSTOUFS(mp)))
return;
if ((si = mount_getspecific(mp, si_mount_data_key)) == NULL)
si = si_mount_init(mp);
ns = UFS_FSNEEDSWAP(fs);
/*
* XXX The following needs to be set before ffs_truncate or
* VOP_READ can be called.
*/
mp->mnt_stat.f_iosize = fs->fs_bsize;
/*
* Process each snapshot listed in the superblock.
*/
vp = NULL;
mutex_enter(&si->si_lock);
for (snaploc = 0; snaploc < FSMAXSNAP; snaploc++) {
if (fs->fs_snapinum[snaploc] == 0)
break;
if ((error = VFS_VGET(mp, fs->fs_snapinum[snaploc],
&vp)) != 0) {
printf("ffs_snapshot_mount: vget failed %d\n", error);
continue;
}
ip = VTOI(vp);
if ((ip->i_flags & SF_SNAPSHOT) == 0) {
printf("ffs_snapshot_mount: non-snapshot inode %d\n",
fs->fs_snapinum[snaploc]);
vput(vp);
vp = NULL;
for (loc = snaploc + 1; loc < FSMAXSNAP; loc++) {
if (fs->fs_snapinum[loc] == 0)
break;
fs->fs_snapinum[loc - 1] = fs->fs_snapinum[loc];
}
fs->fs_snapinum[loc - 1] = 0;
snaploc--;
continue;
}
/*
* Read the block hints list. Use an empty list on
* read errors.
*/
error = vn_rdwr(UIO_READ, vp,
(void *)&snaplistsize, sizeof(snaplistsize),
lblktosize(fs, howmany(fs->fs_size, fs->fs_frag)),
UIO_SYSSPACE, IO_NODELOCKED|IO_UNIT,
l->l_cred, NULL, NULL);
if (error) {
printf("ffs_snapshot_mount: read_1 failed %d\n", error);
snaplistsize = 1;
} else
snaplistsize = ufs_rw64(snaplistsize, ns);
snapblklist = malloc(
snaplistsize * sizeof(ufs2_daddr_t), M_UFSMNT, M_WAITOK);
if (error)
snapblklist[0] = 1;
else {
error = vn_rdwr(UIO_READ, vp, (void *)snapblklist,
snaplistsize * sizeof(ufs2_daddr_t),
lblktosize(fs, howmany(fs->fs_size, fs->fs_frag)),
UIO_SYSSPACE, IO_NODELOCKED|IO_UNIT,
l->l_cred, NULL, NULL);
for (i = 0; i < snaplistsize; i++)
snapblklist[i] = ufs_rw64(snapblklist[i], ns);
if (error) {
printf("ffs_snapshot_mount: read_2 failed %d\n",
error);
snapblklist[0] = 1;
}
}
ip->i_snapblklist = &snapblklist[0];
/*
* If there already exist snapshots on this filesystem, grab a
* reference to their shared lock. If this is the first snapshot
* on this filesystem, we need to allocate a lock for the
* snapshots to share. In either case, acquire the snapshot
* lock and give up our original private lock.
*/
if ((xp = TAILQ_FIRST(&si->si_snapshots)) != NULL) {
VI_LOCK(vp);
vp->v_vnlock = ITOV(xp)->v_vnlock;
} else {
lockinit(&si->si_vnlock, PVFS, "snaplk",
0, LK_CANRECURSE);
VI_LOCK(vp);
vp->v_vnlock = &si->si_vnlock;
}
vn_lock(vp, LK_INTERLOCK | LK_EXCLUSIVE | LK_RETRY);
lockmgr(&vp->v_lock, LK_RELEASE, NULL);
/*
* Link it onto the active snapshot list.
*/
if (ip->i_nextsnap.tqe_prev != 0)
panic("ffs_snapshot_mount: %llu already on list",
(unsigned long long)ip->i_number);
else
TAILQ_INSERT_TAIL(&si->si_snapshots, ip, i_nextsnap);
vp->v_vflag |= VV_SYSTEM;
VOP_UNLOCK(vp, 0);
}
/*
* No usable snapshots found.
*/
if (vp == NULL) {
mutex_exit(&si->si_lock);
return;
}
/*
* Attach the block hints list. We always want to
* use the list from the newest snapshot.
*/
xp = TAILQ_LAST(&si->si_snapshots, inodelst);
si->si_snapblklist = xp->i_snapblklist;
fscow_establish(mp, ffs_copyonwrite, devvp);
si->si_gen++;
mutex_exit(&si->si_lock);
}
/*
* Disassociate snapshot files when unmounting.
*/
void
ffs_snapshot_unmount(struct mount *mp)
{
struct vnode *devvp = VFSTOUFS(mp)->um_devvp;
struct inode *xp;
struct vnode *vp = NULL;
struct snap_info *si;
if ((si = mount_getspecific(mp, si_mount_data_key)) == NULL)
return;
mutex_enter(&si->si_lock);
while ((xp = TAILQ_FIRST(&si->si_snapshots)) != 0) {
vp = ITOV(xp);
vp->v_vnlock = &vp->v_lock;
TAILQ_REMOVE(&si->si_snapshots, xp, i_nextsnap);
xp->i_nextsnap.tqe_prev = 0;
if (xp->i_snapblklist == si->si_snapblklist)
si->si_snapblklist = NULL;
FREE(xp->i_snapblklist, M_UFSMNT);
if (xp->i_ffs_effnlink > 0) {
si->si_gen++;
mutex_exit(&si->si_lock);
vrele(vp);
mutex_enter(&si->si_lock);
}
}
if (vp)
fscow_disestablish(mp, ffs_copyonwrite, devvp);
si->si_gen++;
mutex_exit(&si->si_lock);
}
/*
* Check for need to copy block that is about to be written,
* copying the block if necessary.
*/
static int
ffs_copyonwrite(void *v, struct buf *bp, bool data_valid)
{
struct buf *ibp;
struct fs *fs;
struct inode *ip;
struct vnode *devvp = v, *vp = NULL;
struct mount *mp = devvp->v_specmountpoint;
struct snap_info *si;
void *saved_data = NULL;
ufs2_daddr_t lbn, blkno, *snapblklist;
uint32_t gen;
int lower, upper, mid, s, ns, indiroff, snapshot_locked = 0, error = 0;
/*
* Check for valid snapshots.
*/
if ((si = mount_getspecific(mp, si_mount_data_key)) == NULL)
return 0;
mutex_enter(&si->si_lock);
ip = TAILQ_FIRST(&si->si_snapshots);
if (ip == NULL) {
mutex_exit(&si->si_lock);
return 0;
}
/*
* First check to see if it is in the preallocated list.
* By doing this check we avoid several potential deadlocks.
*/
fs = ip->i_fs;
ns = UFS_FSNEEDSWAP(fs);
lbn = fragstoblks(fs, dbtofsb(fs, bp->b_blkno));
snapblklist = si->si_snapblklist;
upper = si->si_snapblklist[0] - 1;
lower = 1;
while (lower <= upper) {
mid = (lower + upper) / 2;
if (snapblklist[mid] == lbn)
break;
if (snapblklist[mid] < lbn)
lower = mid + 1;
else
upper = mid - 1;
}
if (lower <= upper) {
mutex_exit(&si->si_lock);
return 0;
}
/*
* Not in the precomputed list, so check the snapshots.
*/
if (data_valid && bp->b_bcount == fs->fs_bsize)
saved_data = bp->b_data;
retry:
gen = si->si_gen;
TAILQ_FOREACH(ip, &si->si_snapshots, i_nextsnap) {
vp = ITOV(ip);
/*
* We ensure that everything of our own that needs to be
* copied will be done at the time that ffs_snapshot is
* called. Thus we can skip the check here which can
* deadlock in doing the lookup in ffs_balloc.
*/
if (bp->b_vp == vp)
continue;
if (snapshot_locked == 0) {
mutex_exit(&si->si_lock);
if (VOP_LOCK(vp, LK_EXCLUSIVE | LK_SLEEPFAIL) != 0) {
mutex_enter(&si->si_lock);
goto retry;
}
mutex_enter(&si->si_lock);
snapshot_locked = 1;
if (gen != si->si_gen)
goto retry;
}
/*
* Check to see if block needs to be copied. We do not have
* to hold the snapshot lock while doing this lookup as it
* will never require any additional allocations for the
* snapshot inode.
*/
if (lbn < NDADDR) {
blkno = db_get(ip, lbn);
} else {
mutex_exit(&si->si_lock);
s = cow_enter();
error = ffs_balloc(vp, lblktosize(fs, (off_t)lbn),
fs->fs_bsize, KERNCRED, B_METAONLY, &ibp);
cow_leave(s);
if (error) {
mutex_enter(&si->si_lock);
break;
}
indiroff = (lbn - NDADDR) % NINDIR(fs);
blkno = idb_get(ip, ibp->b_data, indiroff);
brelse(ibp, 0);
mutex_enter(&si->si_lock);
if (gen != si->si_gen)
goto retry;
}
#ifdef DIAGNOSTIC
if (blkno == BLK_SNAP && bp->b_lblkno >= 0)
panic("ffs_copyonwrite: bad copy block");
#endif
if (blkno != 0)
continue;
#ifdef DIAGNOSTIC
if (curlwp->l_pflag & LP_UFSCOW)
printf("ffs_copyonwrite: recursive call\n");
#endif
/*
* Allocate the block into which to do the copy. Since
* multiple processes may all try to copy the same block,
* we have to recheck our need to do a copy if we sleep
* waiting for the lock.
*
* Because all snapshots on a filesystem share a single
* lock, we ensure that we will never be in competition
* with another process to allocate a block.
*/
#ifdef DEBUG
if (snapdebug) {
printf("Copyonwrite: snapino %llu lbn %" PRId64 " for ",
(unsigned long long)ip->i_number, lbn);
if (bp->b_vp == devvp)
printf("fs metadata");
else
printf("inum %llu", (unsigned long long)
VTOI(bp->b_vp)->i_number);
printf(" lblkno %" PRId64 "\n", bp->b_lblkno);
}
#endif
/*
* If we have already read the old block contents, then
* simply copy them to the new block. Note that we need
* to synchronously write snapshots that have not been
* unlinked, and hence will be visible after a crash,
* to ensure their integrity.
*/
mutex_exit(&si->si_lock);
if (saved_data == NULL) {
saved_data = malloc(fs->fs_bsize, M_UFSMNT, M_WAITOK);
if ((error = readfsblk(vp, saved_data, lbn)) != 0) {
free(saved_data, M_UFSMNT);
saved_data = NULL;
mutex_enter(&si->si_lock);
break;
}
}
error = writevnblk(vp, saved_data, lbn);
mutex_enter(&si->si_lock);
if (error)
break;
if (gen != si->si_gen)
goto retry;
}
/*
* Note that we need to synchronously write snapshots that
* have not been unlinked, and hence will be visible after
* a crash, to ensure their integrity.
*/
mutex_exit(&si->si_lock);
if (saved_data && saved_data != bp->b_data)
free(saved_data, M_UFSMNT);
if (snapshot_locked)
VOP_UNLOCK(vp, 0);
return error;
}
/*
* Read the specified block from disk. Vp is usually a snapshot vnode.
*/
static int
readfsblk(struct vnode *vp, void *data, ufs2_daddr_t lbn)
{
int error;
struct inode *ip = VTOI(vp);
struct fs *fs = ip->i_fs;
struct buf *nbp;
nbp = getiobuf();
nbp->b_flags = B_READ;
nbp->b_bcount = nbp->b_bufsize = fs->fs_bsize;
nbp->b_error = 0;
nbp->b_data = data;
nbp->b_blkno = nbp->b_rawblkno = fsbtodb(fs, blkstofrags(fs, lbn));
nbp->b_proc = NULL;
nbp->b_dev = ip->i_devvp->v_rdev;
nbp->b_vp = NULLVP;
bdev_strategy(nbp);
error = biowait(nbp);
putiobuf(nbp);
return error;
}
#if !defined(FFS_NO_SNAPSHOT)
/*
* Read the specified block. Bypass UBC to prevent deadlocks.
*/
static int
readvnblk(struct vnode *vp, void *data, ufs2_daddr_t lbn)
{
int error;
daddr_t bn;
off_t offset;
struct inode *ip = VTOI(vp);
struct fs *fs = ip->i_fs;
error = VOP_BMAP(vp, lbn, NULL, &bn, NULL);
if (error)
return error;
if (bn != (daddr_t)-1) {
offset = dbtob(bn);
simple_lock(&vp->v_interlock);
error = VOP_PUTPAGES(vp, trunc_page(offset),
round_page(offset+fs->fs_bsize),
PGO_CLEANIT|PGO_SYNCIO|PGO_FREE);
if (error)
return error;
return readfsblk(vp, data, fragstoblks(fs, dbtofsb(fs, bn)));
}
bzero(data, fs->fs_bsize);
return 0;
}
#endif /* !defined(FFS_NO_SNAPSHOT) */
/*
* Write the specified block. Bypass UBC to prevent deadlocks.
*/
static int
writevnblk(struct vnode *vp, void *data, ufs2_daddr_t lbn)
{
int s, error;
off_t offset;
struct buf *bp;
struct inode *ip = VTOI(vp);
struct fs *fs = ip->i_fs;
offset = lblktosize(fs, (off_t)lbn);
s = cow_enter();
simple_lock(&vp->v_interlock);
error = VOP_PUTPAGES(vp, trunc_page(offset),
round_page(offset+fs->fs_bsize), PGO_CLEANIT|PGO_SYNCIO|PGO_FREE);
if (error == 0)
error = ffs_balloc(vp, lblktosize(fs, (off_t)lbn),
fs->fs_bsize, KERNCRED, B_SYNC, &bp);
cow_leave(s);
if (error)
return error;
bcopy(data, bp->b_data, fs->fs_bsize);
bp->b_flags |= B_NOCACHE;
return bwrite(bp);
}
/*
* Set/reset lwp's LP_UFSCOW flag.
* May be called recursive.
*/
static inline int
cow_enter(void)
{
struct lwp *l = curlwp;
if (l->l_pflag & LP_UFSCOW) {
return 0;
} else {
l->l_pflag |= LP_UFSCOW;
return LP_UFSCOW;
}
}
static inline void
cow_leave(int flag)
{
struct lwp *l = curlwp;
l->l_pflag &= ~flag;
}
/*
* Get/Put direct block from inode or buffer containing disk addresses. Take
* care for fs type (UFS1/UFS2) and byte swapping. These functions should go
* into a global include.
*/
static inline ufs2_daddr_t
db_get(struct inode *ip, int loc)
{
if (ip->i_ump->um_fstype == UFS1)
return ufs_rw32(ip->i_ffs1_db[loc], UFS_IPNEEDSWAP(ip));
else
return ufs_rw64(ip->i_ffs2_db[loc], UFS_IPNEEDSWAP(ip));
}
static inline void
db_assign(struct inode *ip, int loc, ufs2_daddr_t val)
{
if (ip->i_ump->um_fstype == UFS1)
ip->i_ffs1_db[loc] = ufs_rw32(val, UFS_IPNEEDSWAP(ip));
else
ip->i_ffs2_db[loc] = ufs_rw64(val, UFS_IPNEEDSWAP(ip));
}
static inline ufs2_daddr_t
idb_get(struct inode *ip, void *bf, int loc)
{
if (ip->i_ump->um_fstype == UFS1)
return ufs_rw32(((ufs1_daddr_t *)(bf))[loc],
UFS_IPNEEDSWAP(ip));
else
return ufs_rw64(((ufs2_daddr_t *)(bf))[loc],
UFS_IPNEEDSWAP(ip));
}
static inline void
idb_assign(struct inode *ip, void *bf, int loc, ufs2_daddr_t val)
{
if (ip->i_ump->um_fstype == UFS1)
((ufs1_daddr_t *)(bf))[loc] =
ufs_rw32(val, UFS_IPNEEDSWAP(ip));
else
((ufs2_daddr_t *)(bf))[loc] =
ufs_rw64(val, UFS_IPNEEDSWAP(ip));
}
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