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NetBSD/sys/ufs/ffs/ffs_snapshot.c

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/* $NetBSD: ffs_snapshot.c,v 1.152 2020/04/18 19:18:34 christos 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 1.152 2020/04/18 19:18:34 christos Exp $");
#if defined(_KERNEL_OPT)
#include "opt_ffs.h"
#include "opt_quota.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 <sys/wapbl.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/ufs/ufs_wapbl.h>
#include <ufs/ffs/fs.h>
#include <ufs/ffs/ffs_extern.h>
#include <uvm/uvm.h>
TAILQ_HEAD(inodelst, inode); /* List of active snapshots */
struct snap_info {
kmutex_t si_lock; /* Lock this snapinfo */
kmutex_t si_snaplock; /* Snapshot vnode common lock */
lwp_t *si_owner; /* Snaplock owner */
struct inodelst si_snapshots; /* List of active snapshots */
daddr_t *si_snapblklist; /* Snapshot block hints list */
uint32_t si_gen; /* Incremented on change */
};
#if !defined(FFS_NO_SNAPSHOT)
typedef int (*acctfunc_t)
(struct vnode *, void *, int, int, struct fs *, daddr_t, int);
static int snapshot_setup(struct mount *, struct vnode *);
static int snapshot_copyfs(struct mount *, struct vnode *, void **);
static int snapshot_expunge(struct mount *, struct vnode *,
struct fs *, daddr_t *, daddr_t **);
static int snapshot_expunge_snap(struct mount *, struct vnode *,
struct fs *, daddr_t);
static int snapshot_writefs(struct mount *, struct vnode *, void *);
static int cgaccount(struct vnode *, int, int *);
static int cgaccount1(int, struct vnode *, void *, int);
static int expunge(struct vnode *, struct inode *, struct fs *,
acctfunc_t, int);
static int indiracct(struct vnode *, struct vnode *, int, daddr_t,
daddr_t, daddr_t, daddr_t, daddr_t, struct fs *, acctfunc_t, int);
static int fullacct(struct vnode *, void *, int, int, struct fs *,
daddr_t, int);
static int snapacct(struct vnode *, void *, int, int, struct fs *,
daddr_t, int);
static int mapacct(struct vnode *, void *, int, int, struct fs *,
daddr_t, int);
#endif /* !defined(FFS_NO_SNAPSHOT) */
static int ffs_copyonwrite(void *, struct buf *, bool);
static int snapblkaddr(struct vnode *, daddr_t, daddr_t *);
static int rwfsblk(struct vnode *, int, void *, daddr_t);
static int syncsnap(struct vnode *);
static int wrsnapblk(struct vnode *, void *, daddr_t);
#if !defined(FFS_NO_SNAPSHOT)
static int blocks_in_journal(struct fs *);
#endif
static inline bool is_active_snapshot(struct snap_info *, struct inode *);
static inline daddr_t db_get(struct inode *, int);
static inline void db_assign(struct inode *, int, daddr_t);
static inline daddr_t ib_get(struct inode *, int);
static inline daddr_t idb_get(struct inode *, void *, int);
static inline void idb_assign(struct inode *, void *, int, daddr_t);
#ifdef DEBUG
static int snapdebug = 0;
#endif
int
ffs_snapshot_init(struct ufsmount *ump)
{
struct snap_info *si;
si = ump->um_snapinfo = kmem_alloc(sizeof(*si), KM_SLEEP);
TAILQ_INIT(&si->si_snapshots);
mutex_init(&si->si_lock, MUTEX_DEFAULT, IPL_NONE);
mutex_init(&si->si_snaplock, MUTEX_DEFAULT, IPL_NONE);
si->si_owner = NULL;
si->si_gen = 0;
si->si_snapblklist = NULL;
return 0;
}
void
ffs_snapshot_fini(struct ufsmount *ump)
{
struct snap_info *si;
si = ump->um_snapinfo;
ump->um_snapinfo = NULL;
KASSERT(TAILQ_EMPTY(&si->si_snapshots));
mutex_destroy(&si->si_lock);
mutex_destroy(&si->si_snaplock);
KASSERT(si->si_snapblklist == NULL);
kmem_free(si, sizeof(*si));
}
/*
* 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) */
bool suspended = false;
int error, redo = 0, snaploc;
void *sbbuf = NULL;
daddr_t *snaplist = NULL, snaplistsize = 0;
struct buf *bp, *nbp;
struct fs *copy_fs = NULL;
struct fs *fs = VFSTOUFS(mp)->um_fs;
struct inode *ip = VTOI(vp);
struct lwp *l = curlwp;
struct snap_info *si = VFSTOUFS(mp)->um_snapinfo;
struct timespec ts;
struct timeval starttime;
#ifdef DEBUG
struct timeval endtime;
#endif
struct vnode *devvp = ip->i_devvp;
/*
* If the vnode already is a snapshot, return.
*/
if ((ip->i_flags & SF_SNAPSHOT)) {
if ((ip->i_flags & SF_SNAPINVAL))
return EINVAL;
if (ctime) {
ctime->tv_sec = DIP(ip, mtime);
ctime->tv_nsec = DIP(ip, mtimensec);
}
return 0;
}
/*
* Check for free snapshot slot in the superblock.
*/
for (snaploc = 0; snaploc < FSMAXSNAP; snaploc++)
if (fs->fs_snapinum[snaploc] == 0)
break;
if (snaploc == FSMAXSNAP)
return (ENOSPC);
/*
* Prepare the vnode to become a snapshot.
*/
error = snapshot_setup(mp, vp);
if (error)
goto out;
/*
* 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.
*/
error = cgaccount(vp, 1, NULL);
if (error)
goto out;
/*
* snapshot is now valid
*/
ip->i_flags &= ~SF_SNAPINVAL;
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.
*/
error = VOP_FSYNC(vp, l->l_cred, FSYNC_WAIT, 0, 0);
if (error)
goto out;
VOP_UNLOCK(vp);
/*
* All allocations are done, so we can now suspend the filesystem.
*/
error = vfs_suspend(vp->v_mount, 0);
if (error == 0) {
suspended = true;
vrele_flush(vp->v_mount);
error = VFS_SYNC(vp->v_mount, MNT_WAIT, curlwp->l_cred);
}
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
if (error)
goto out;
getmicrotime(&starttime);
/*
* First, copy all the cylinder group maps that have changed.
*/
error = cgaccount(vp, 2, &redo);
if (error)
goto out;
/*
* Create a copy of the superblock and its summary information.
*/
error = snapshot_copyfs(mp, vp, &sbbuf);
if (error)
goto out;
copy_fs = (struct fs *)((char *)sbbuf + ffs_blkoff(fs, fs->fs_sblockloc));
/*
* Expunge unlinked files from our view.
*/
error = snapshot_expunge(mp, vp, copy_fs, &snaplistsize, &snaplist);
if (error)
goto out;
/*
* Record snapshot inode. Since this is the newest snapshot,
* it must be placed at the end of the list.
*/
if (ip->i_nlink > 0)
fs->fs_snapinum[snaploc] = ip->i_number;
mutex_enter(&si->si_lock);
if (is_active_snapshot(si, ip))
panic("ffs_snapshot: %"PRIu64" already on list", ip->i_number);
TAILQ_INSERT_TAIL(&si->si_snapshots, ip, i_nextsnap);
if (TAILQ_FIRST(&si->si_snapshots) == ip) {
/*
* If this is the first snapshot on this filesystem, put the
* preliminary list in place and establish the cow handler.
*/
si->si_snapblklist = snaplist;
fscow_establish(mp, ffs_copyonwrite, devvp);
}
si->si_gen++;
mutex_exit(&si->si_lock);
vp->v_vflag |= VV_SYSTEM;
/*
* 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;
/*
* Copy allocation information from all snapshots and then
* expunge them from our view.
*/
error = snapshot_expunge_snap(mp, vp, copy_fs, snaplistsize);
if (error)
goto out;
/*
* Write the superblock and its summary information to the snapshot.
*/
error = snapshot_writefs(mp, vp, sbbuf);
if (error)
goto out;
/*
* We're nearly done, ensure that the snapshot is completely on disk.
*/
error = VOP_FSYNC(vp, l->l_cred, FSYNC_WAIT, 0, 0);
if (error)
goto out;
/*
* Invalidate and free all pages on the snapshot vnode.
* We will read and write through the buffercache.
*/
rw_enter(vp->v_uobj.vmobjlock, RW_WRITER);
error = VOP_PUTPAGES(vp, 0, 0,
PGO_ALLPAGES | PGO_CLEANIT | PGO_SYNCIO | PGO_FREE);
if (error)
goto out;
/*
* Invalidate short ( < fs_bsize ) buffers. We will always read
* full size buffers later.
*/
mutex_enter(&bufcache_lock);
KASSERT(LIST_FIRST(&vp->v_dirtyblkhd) == NULL);
for (bp = LIST_FIRST(&vp->v_cleanblkhd); bp; bp = nbp) {
nbp = LIST_NEXT(bp, b_vnbufs);
if (bp->b_bcount == fs->fs_bsize)
continue;
error = bbusy(bp, false, 0, NULL);
if (error != 0) {
if (error == EPASSTHROUGH) {
nbp = LIST_FIRST(&vp->v_cleanblkhd);
continue;
}
break;
}
brelsel(bp, BC_INVAL | BC_VFLUSH);
}
mutex_exit(&bufcache_lock);
out:
if (sbbuf != NULL) {
free(copy_fs->fs_csp, M_UFSMNT);
free(sbbuf, M_UFSMNT);
}
if (fs->fs_active != NULL) {
free(fs->fs_active, M_DEVBUF);
fs->fs_active = NULL;
}
mutex_enter(&si->si_lock);
if (snaplist != NULL) {
if (si->si_snapblklist == snaplist)
si->si_snapblklist = NULL;
free(snaplist, M_UFSMNT);
}
if (error) {
fs->fs_snapinum[snaploc] = 0;
} else {
/*
* As this is the newest list, it is the most inclusive, so
* should replace the previous list.
*/
si->si_snapblklist = ip->i_snapblklist;
}
si->si_gen++;
mutex_exit(&si->si_lock);
if (suspended) {
VOP_UNLOCK(vp);
vfs_resume(vp->v_mount);
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
#ifdef DEBUG
getmicrotime(&endtime);
timersub(&endtime, &starttime, &endtime);
printf("%s: suspended %lld.%03d sec, redo %d of %d\n",
mp->mnt_stat.f_mntonname, (long long)endtime.tv_sec,
endtime.tv_usec / 1000, redo, fs->fs_ncg);
#endif
}
if (error) {
if (UFS_WAPBL_BEGIN(mp) == 0) {
/*
* We depend on ffs_truncate() to call ffs_snapremove()
* before it may return an error. On failed
* ffs_truncate() we have normal file with leaked
* (meta-) data, but no snapshot to use.
*/
(void) ffs_truncate(vp, (off_t)0, 0, NOCRED);
UFS_WAPBL_END(mp);
}
} else if (ip->i_nlink > 0)
vref(vp);
return (error);
}
/*
* Prepare vnode to become a snapshot.
*/
static int
snapshot_setup(struct mount *mp, struct vnode *vp)
{
int error, n, len, loc, cg;
daddr_t blkno, numblks;
struct buf *ibp, *nbp;
struct fs *fs = VFSTOUFS(mp)->um_fs;
struct lwp *l = curlwp;
const int wbreak = blocks_in_journal(fs)/8;
struct inode *ip = VTOI(vp);
/*
* Check mount, readonly reference and owner.
*/
if (vp->v_mount != mp)
return EXDEV;
if (vp->v_writecount != 0)
return EBUSY;
error = kauth_authorize_system(l->l_cred, KAUTH_SYSTEM_FS_SNAPSHOT,
0, mp, vp, NULL);
if (error)
return EACCES;
/*
* Must completely truncate the file here. Allocated
* blocks on a snapshot mean that block has been copied
* on write, see ffs_copyonwrite() testing "blkno != 0"
*/
error = ufs_truncate_all(vp);
if (error)
return error;
/* Change inode to snapshot type file. */
error = UFS_WAPBL_BEGIN(mp);
if (error)
return error;
#if defined(QUOTA) || defined(QUOTA2)
/* shapshot inodes are not accounted in quotas */
chkiq(ip, -1, l->l_cred, 0);
#endif
ip->i_flags |= (SF_SNAPSHOT | SF_SNAPINVAL);
DIP_ASSIGN(ip, flags, ip->i_flags);
ip->i_flag |= IN_CHANGE | IN_UPDATE;
ffs_update(vp, NULL, NULL, UPDATE_WAIT);
UFS_WAPBL_END(mp);
KASSERT(ip->i_flags & SF_SNAPSHOT);
/*
* 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, UFS_FSNEEDSWAP(fs));
error = vn_rdwr(UIO_WRITE, vp,
(void *)&blkno, sizeof(blkno), ffs_lblktosize(fs, (off_t)numblks),
UIO_SYSSPACE, IO_NODELOCKED|IO_UNIT, l->l_cred, NULL, NULL);
if (error)
return error;
/*
* 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.
*/
error = UFS_WAPBL_BEGIN(mp);
if (error)
return error;
for (blkno = UFS_NDADDR, n = 0; blkno < numblks; blkno += FFS_NINDIR(fs)) {
error = ffs_balloc(vp, ffs_lblktosize(fs, (off_t)blkno),
fs->fs_bsize, l->l_cred, B_METAONLY, &ibp);
if (error)
goto out;
brelse(ibp, 0);
if (wbreak > 0 && (++n % wbreak) == 0) {
UFS_WAPBL_END(mp);
error = UFS_WAPBL_BEGIN(mp);
if (error)
return error;
}
}
/*
* Allocate copies for the superblock and its summary information.
*/
error = ffs_balloc(vp, fs->fs_sblockloc, fs->fs_sbsize, l->l_cred,
0, &nbp);
if (error)
goto out;
bawrite(nbp);
blkno = ffs_fragstoblks(fs, fs->fs_csaddr);
len = howmany(fs->fs_cssize, fs->fs_bsize);
for (loc = 0; loc < len; loc++) {
error = ffs_balloc(vp, ffs_lblktosize(fs, (off_t)(blkno + loc)),
fs->fs_bsize, l->l_cred, 0, &nbp);
if (error)
goto out;
bawrite(nbp);
if (wbreak > 0 && (++n % wbreak) == 0) {
UFS_WAPBL_END(mp);
error = UFS_WAPBL_BEGIN(mp);
if (error)
return error;
}
}
/*
* Allocate all cylinder group blocks.
*/
for (cg = 0; cg < fs->fs_ncg; cg++) {
error = ffs_balloc(vp, ffs_lfragtosize(fs, cgtod(fs, cg)),
fs->fs_bsize, l->l_cred, 0, &nbp);
if (error)
goto out;
bawrite(nbp);
if (wbreak > 0 && (++n % wbreak) == 0) {
UFS_WAPBL_END(mp);
error = UFS_WAPBL_BEGIN(mp);
if (error)
return error;
}
}
out:
UFS_WAPBL_END(mp);
return error;
}
/*
* Create a copy of the superblock and its summary information.
* It is up to the caller to free copyfs and copy_fs->fs_csp.
*/
static int
snapshot_copyfs(struct mount *mp, struct vnode *vp, void **sbbuf)
{
int error, i, len, loc, size;
void *space;
int32_t *lp;
struct buf *bp;
struct fs *copyfs, *fs = VFSTOUFS(mp)->um_fs;
struct vnode *devvp = VTOI(vp)->i_devvp;
/*
* 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 = ffs_blkoff(fs, fs->fs_sblockloc);
if (loc > 0)
memset(*sbbuf, 0, loc);
copyfs = (struct fs *)((char *)(*sbbuf) + loc);
memcpy(copyfs, 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 = ffs_blkroundup(fs, fs->fs_cssize);
if (fs->fs_contigsumsize > 0)
size += fs->fs_ncg * sizeof(int32_t);
space = malloc(size, M_UFSMNT, M_WAITOK);
copyfs->fs_csp = space;
memcpy(copyfs->fs_csp, 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, FFS_FSBTODB(fs, fs->fs_csaddr + loc),
len, 0, &bp)) != 0) {
free(copyfs->fs_csp, M_UFSMNT);
free(*sbbuf, M_UFSMNT);
*sbbuf = NULL;
return error;
}
memcpy(space, bp->b_data, (u_int)len);
space = (char *)space + len;
brelse(bp, BC_INVAL | BC_NOCACHE);
}
if (fs->fs_contigsumsize > 0) {
copyfs->fs_maxcluster = lp = space;
for (i = 0; i < fs->fs_ncg; i++)
*lp++ = fs->fs_contigsumsize;
}
if (mp->mnt_wapbl)
copyfs->fs_flags &= ~FS_DOWAPBL;
return 0;
}
struct snapshot_expunge_ctx {
struct vnode *logvp;
struct lwp *l;
struct vnode *vp;
struct fs *copy_fs;
};
static bool
snapshot_expunge_selector(void *cl, struct vnode *xvp)
{
struct vattr vat;
struct snapshot_expunge_ctx *c = cl;
struct inode *xp;
KASSERT(mutex_owned(xvp->v_interlock));
xp = VTOI(xvp);
if (xvp->v_type == VNON || VTOI(xvp) == NULL ||
(xp->i_flags & SF_SNAPSHOT))
return false;
#ifdef DEBUG
if (snapdebug)
vprint("ffs_snapshot: busy vnode", xvp);
#endif
if (xvp == c->logvp)
return true;
if (VOP_GETATTR(xvp, &vat, c->l->l_cred) == 0 &&
vat.va_nlink > 0)
return false;
if (ffs_checkfreefile(c->copy_fs, c->vp, xp->i_number))
return false;
return true;
}
/*
* 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.
* Note that we skip unlinked snapshot files as they will be handled separately.
* Calculate the snapshot list size and create a preliminary list.
*/
static int
snapshot_expunge(struct mount *mp, struct vnode *vp, struct fs *copy_fs,
daddr_t *snaplistsize, daddr_t **snaplist)
{
int cg, error = 0, len, loc;
daddr_t blkno, *blkp;
struct fs *fs = VFSTOUFS(mp)->um_fs;
struct inode *xp;
struct lwp *l = curlwp;
struct vnode *logvp = NULL, *xvp;
struct vnode_iterator *marker;
struct snapshot_expunge_ctx ctx;
*snaplist = NULL;
/*
* Get the log inode if any.
*/
if ((fs->fs_flags & FS_DOWAPBL) &&
fs->fs_journal_location == UFS_WAPBL_JOURNALLOC_IN_FILESYSTEM) {
error = VFS_VGET(mp, fs->fs_journallocs[UFS_WAPBL_INFS_INO],
LK_EXCLUSIVE, &logvp);
if (error)
goto out;
}
/*
* 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 */;
vfs_vnode_iterator_init(mp, &marker);
ctx.logvp = logvp;
ctx.l = l;
ctx.vp = vp;
ctx.copy_fs = copy_fs;
while ((xvp = vfs_vnode_iterator_next(marker, snapshot_expunge_selector,
&ctx)))
{
/*
* If there is a fragment, clear it here.
*/
xp = VTOI(xvp);
blkno = 0;
loc = howmany(xp->i_size, fs->fs_bsize) - 1;
if (loc < UFS_NDADDR) {
len = ffs_fragroundup(fs, ffs_blkoff(fs, xp->i_size));
if (len > 0 && len < fs->fs_bsize) {
error = UFS_WAPBL_BEGIN(mp);
if (error) {
vrele(xvp);
vfs_vnode_iterator_destroy(marker);
goto out;
}
ffs_blkfree_snap(copy_fs, vp, db_get(xp, loc),
len, xp->i_number);
blkno = db_get(xp, loc);
db_assign(xp, loc, 0);
UFS_WAPBL_END(mp);
}
}
*snaplistsize += 1;
error = expunge(vp, xp, copy_fs, fullacct, BLK_NOCOPY);
if (blkno)
db_assign(xp, loc, blkno);
if (!error) {
error = UFS_WAPBL_BEGIN(mp);
if (!error) {
error = ffs_freefile_snap(copy_fs, vp,
xp->i_number, xp->i_mode);
UFS_WAPBL_END(mp);
}
}
vrele(xvp);
if (error) {
vfs_vnode_iterator_destroy(marker);
goto out;
}
}
vfs_vnode_iterator_destroy(marker);
/*
* Create a preliminary list of preallocated snapshot blocks.
*/
*snaplist = malloc(*snaplistsize * sizeof(daddr_t), M_UFSMNT, M_WAITOK);
blkp = &(*snaplist)[1];
*blkp++ = ffs_lblkno(fs, fs->fs_sblockloc);
blkno = ffs_fragstoblks(fs, fs->fs_csaddr);
for (cg = 0; cg < fs->fs_ncg; cg++) {
if (ffs_fragstoblks(fs, cgtod(fs, cg)) > blkno)
break;
*blkp++ = ffs_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++ = ffs_fragstoblks(fs, cgtod(fs, cg));
(*snaplist)[0] = blkp - &(*snaplist)[0];
out:
if (logvp != NULL)
vput(logvp);
if (error && *snaplist != NULL) {
free(*snaplist, M_UFSMNT);
*snaplist = NULL;
}
return error;
}
/*
* Copy allocation information from all the snapshots in this snapshot and
* then expunge them from its view. Also, collect the list of allocated
* blocks in i_snapblklist.
*/
static int
snapshot_expunge_snap(struct mount *mp, struct vnode *vp,
struct fs *copy_fs, daddr_t snaplistsize)
{
int error = 0, i;
daddr_t numblks, *snaplist = NULL;
struct fs *fs = VFSTOUFS(mp)->um_fs;
struct inode *ip = VTOI(vp), *xp;
struct lwp *l = curlwp;
struct snap_info *si = VFSTOUFS(mp)->um_snapinfo;
TAILQ_FOREACH(xp, &si->si_snapshots, i_nextsnap) {
if (xp != ip) {
error = expunge(vp, xp, fs, snapacct, BLK_SNAP);
if (error)
break;
}
if (xp->i_nlink != 0)
continue;
error = UFS_WAPBL_BEGIN(mp);
if (error)
break;
error = ffs_freefile_snap(copy_fs, vp, xp->i_number, xp->i_mode);
UFS_WAPBL_END(mp);
if (error)
break;
}
if (error)
goto out;
/*
* Allocate space for the full list of preallocated snapshot blocks.
*/
snaplist = malloc(snaplistsize * sizeof(daddr_t), M_UFSMNT, M_WAITOK);
ip->i_snapblklist = &snaplist[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.
*/
error = expunge(vp, ip, copy_fs, mapacct, BLK_SNAP);
if (error)
goto out;
if (snaplistsize < ip->i_snapblklist - snaplist)
panic("ffs_snapshot: list too small");
snaplistsize = ip->i_snapblklist - snaplist;
snaplist[0] = snaplistsize;
ip->i_snapblklist = &snaplist[0];
/*
* Write out the list of allocated blocks to the end of the snapshot.
*/
numblks = howmany(fs->fs_size, fs->fs_frag);
for (i = 0; i < snaplistsize; i++)
snaplist[i] = ufs_rw64(snaplist[i], UFS_FSNEEDSWAP(fs));
error = vn_rdwr(UIO_WRITE, vp, (void *)snaplist,
snaplistsize * sizeof(daddr_t), ffs_lblktosize(fs, (off_t)numblks),
UIO_SYSSPACE, IO_NODELOCKED | IO_UNIT, l->l_cred, NULL, NULL);
for (i = 0; i < snaplistsize; i++)
snaplist[i] = ufs_rw64(snaplist[i], UFS_FSNEEDSWAP(fs));
out:
if (error && snaplist != NULL) {
free(snaplist, M_UFSMNT);
ip->i_snapblklist = NULL;
}
return error;
}
/*
* Write the superblock and its summary information to the snapshot.
* Make sure, the first UFS_NDADDR blocks get copied to the snapshot.
*/
static int
snapshot_writefs(struct mount *mp, struct vnode *vp, void *sbbuf)
{
int error, len, loc;
void *space;
daddr_t blkno;
struct buf *bp;
struct fs *copyfs, *fs = VFSTOUFS(mp)->um_fs;
struct inode *ip = VTOI(vp);
struct lwp *l = curlwp;
copyfs = (struct fs *)((char *)sbbuf + ffs_blkoff(fs, fs->fs_sblockloc));
/*
* Write the superblock and its summary information
* to the snapshot.
*/
blkno = ffs_fragstoblks(fs, fs->fs_csaddr);
len = howmany(fs->fs_cssize, fs->fs_bsize);
space = copyfs->fs_csp;
#ifdef FFS_EI
if (UFS_FSNEEDSWAP(fs)) {
ffs_sb_swap(copyfs, copyfs);
ffs_csum_swap(space, space, fs->fs_cssize);
}
#endif
error = UFS_WAPBL_BEGIN(mp);
if (error)
return error;
for (loc = 0; loc < len; loc++) {
error = bread(vp, blkno + loc, fs->fs_bsize,
B_MODIFY, &bp);
if (error) {
break;
}
memcpy(bp->b_data, space, fs->fs_bsize);
space = (char *)space + fs->fs_bsize;
bawrite(bp);
}
if (error)
goto out;
error = bread(vp, ffs_lblkno(fs, fs->fs_sblockloc),
fs->fs_bsize, B_MODIFY, &bp);
if (error) {
goto out;
} else {
memcpy(bp->b_data, sbbuf, fs->fs_bsize);
bawrite(bp);
}
/*
* Copy the first UFS_NDADDR blocks to the snapshot so
* ffs_copyonwrite() and ffs_snapblkfree() will always work on
* indirect blocks.
*/
for (loc = 0; loc < UFS_NDADDR; loc++) {
if (db_get(ip, loc) != 0)
continue;
error = ffs_balloc(vp, ffs_lblktosize(fs, (off_t)loc),
fs->fs_bsize, l->l_cred, 0, &bp);
if (error)
break;
error = rwfsblk(vp, B_READ, bp->b_data, loc);
if (error) {
brelse(bp, 0);
break;
}
bawrite(bp);
}
out:
UFS_WAPBL_END(mp);
return error;
}
/*
* Copy all cylinder group maps.
*/
static int
cgaccount(struct vnode *vp, int passno, int *redo)
{
int cg, error = 0;
struct buf *nbp;
struct fs *fs = VTOI(vp)->i_fs;
if (redo != NULL)
*redo = 0;
if (passno == 1)
fs->fs_active = malloc(howmany(fs->fs_ncg, NBBY),
M_DEVBUF, M_WAITOK | M_ZERO);
for (cg = 0; cg < fs->fs_ncg; cg++) {
if (passno == 2 && ACTIVECG_ISSET(fs, cg))
continue;
if (redo != NULL)
*redo += 1;
error = UFS_WAPBL_BEGIN(vp->v_mount);
if (error)
return error;
error = ffs_balloc(vp, ffs_lfragtosize(fs, cgtod(fs, cg)),
fs->fs_bsize, curlwp->l_cred, 0, &nbp);
if (error) {
UFS_WAPBL_END(vp->v_mount);
break;
}
error = cgaccount1(cg, vp, nbp->b_data, passno);
bawrite(nbp);
UFS_WAPBL_END(vp->v_mount);
if (error)
break;
}
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
cgaccount1(int cg, struct vnode *vp, void *data, int passno)
{
struct buf *bp, *ibp;
struct inode *ip;
struct cg *cgp;
struct fs *fs;
struct lwp *l = curlwp;
daddr_t base, numblks;
int error, len, loc, ns __unused, indiroff;
ip = VTOI(vp);
fs = ip->i_fs;
ns = UFS_FSNEEDSWAP(fs);
error = bread(ip->i_devvp, FFS_FSBTODB(fs, cgtod(fs, cg)),
(int)fs->fs_cgsize, 0, &bp);
if (error) {
return (error);
}
cgp = (struct cg *)bp->b_data;
if (!cg_chkmagic(cgp, ns)) {
brelse(bp, 0);
return (EIO);
}
ACTIVECG_SET(fs, cg);
memcpy(data, bp->b_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 < UFS_NDADDR) {
for ( ; loc < UFS_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, ffs_lblktosize(fs, (off_t)(base + loc)),
fs->fs_bsize, l->l_cred, B_METAONLY, &ibp)) != 0)
return (error);
indiroff = (base + loc - UFS_NDADDR) % FFS_NINDIR(fs);
for ( ; loc < len; loc++, indiroff++) {
if (indiroff >= FFS_NINDIR(fs)) {
bawrite(ibp);
if ((error = ffs_balloc(vp,
ffs_lblktosize(fs, (off_t)(base + loc)),
fs->fs_bsize, l->l_cred, 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.
*/
static int
expunge(struct vnode *snapvp, struct inode *cancelip, struct fs *fs,
acctfunc_t acctfunc, int expungetype)
{
int i, error, ns __unused;
daddr_t lbn, rlbn;
daddr_t len, blkno, numblks, blksperindir;
struct ufs1_dinode *dip1;
struct ufs2_dinode *dip2;
struct lwp *l = curlwp;
void *bap;
struct buf *bp;
struct mount *mp;
ns = UFS_FSNEEDSWAP(fs);
mp = snapvp->v_mount;
error = UFS_WAPBL_BEGIN(mp);
if (error)
return error;
/*
* Prepare to expunge the inode. If its inode block has not
* yet been copied, then allocate and fill the copy.
*/
lbn = ffs_fragstoblks(fs, ino_to_fsba(fs, cancelip->i_number));
error = snapblkaddr(snapvp, lbn, &blkno);
if (error)
return error;
if (blkno != 0) {
error = bread(snapvp, lbn, fs->fs_bsize,
B_MODIFY, &bp);
} else {
error = ffs_balloc(snapvp, ffs_lblktosize(fs, (off_t)lbn),
fs->fs_bsize, l->l_cred, 0, &bp);
if (! error)
error = rwfsblk(snapvp, B_READ, bp->b_data, lbn);
}
if (error) {
UFS_WAPBL_END(mp);
return error;
}
/*
* Set a snapshot inode to be a zero length file, regular files
* or unlinked snapshots to be completely unallocated.
*/
if (fs->fs_magic == FS_UFS1_MAGIC) {
dip1 = (struct ufs1_dinode *)bp->b_data +
ino_to_fsbo(fs, cancelip->i_number);
if (cancelip->i_flags & SF_SNAPSHOT) {
dip1->di_flags =
ufs_rw32(ufs_rw32(dip1->di_flags, ns) |
SF_SNAPINVAL, ns);
}
if (expungetype == BLK_NOCOPY || cancelip->i_nlink == 0)
dip1->di_mode = 0;
dip1->di_size = 0;
dip1->di_blocks = 0;
memset(&dip1->di_db[0], 0, (UFS_NDADDR + UFS_NIADDR) * sizeof(int32_t));
} else {
dip2 = (struct ufs2_dinode *)bp->b_data +
ino_to_fsbo(fs, cancelip->i_number);
if (cancelip->i_flags & SF_SNAPSHOT) {
dip2->di_flags =
ufs_rw32(ufs_rw32(dip2->di_flags, ns) |
SF_SNAPINVAL, ns);
}
if (expungetype == BLK_NOCOPY || cancelip->i_nlink == 0)
dip2->di_mode = 0;
dip2->di_size = 0;
dip2->di_blocks = 0;
memset(&dip2->di_db[0], 0, (UFS_NDADDR + UFS_NIADDR) * sizeof(int64_t));
}
bdwrite(bp);
UFS_WAPBL_END(mp);
/*
* Now go through and expunge all the blocks in the file
* using the function requested.
*/
numblks = howmany(cancelip->i_size, fs->fs_bsize);
if (fs->fs_magic == FS_UFS1_MAGIC)
bap = &cancelip->i_ffs1_db[0];
else
bap = &cancelip->i_ffs2_db[0];
error = (*acctfunc)(snapvp, bap, 0, UFS_NDADDR, fs, 0, expungetype);
if (error)
return (error);
if (fs->fs_magic == FS_UFS1_MAGIC)
bap = &cancelip->i_ffs1_ib[0];
else
bap = &cancelip->i_ffs2_ib[0];
error = (*acctfunc)(snapvp, bap, 0, UFS_NIADDR, fs, -1, expungetype);
if (error)
return (error);
blksperindir = 1;
lbn = -UFS_NDADDR;
len = numblks - UFS_NDADDR;
rlbn = UFS_NDADDR;
for (i = 0; len > 0 && i < UFS_NIADDR; i++) {
error = indiracct(snapvp, ITOV(cancelip), i,
ib_get(cancelip, i), lbn, rlbn, len,
blksperindir, fs, acctfunc, expungetype);
if (error)
return (error);
blksperindir *= FFS_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(struct vnode *snapvp, struct vnode *cancelvp, int level,
daddr_t blkno, daddr_t lbn, daddr_t rlbn, daddr_t remblks,
daddr_t blksperindir, struct fs *fs, acctfunc_t acctfunc, int expungetype)
{
int error, num, i;
daddr_t subblksperindir;
struct indir indirs[UFS_NIADDR + 2];
daddr_t last;
void *bap;
struct buf *bp;
if (blkno == 0) {
if (expungetype == BLK_NOCOPY)
return (0);
panic("indiracct: 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: 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.
*/
error = ffs_getblk(cancelvp, lbn, FFS_FSBTODB(fs, blkno), fs->fs_bsize,
false, &bp);
if (error)
return error;
if ((bp->b_oflags & (BO_DONE | BO_DELWRI)) == 0 && (error =
rwfsblk(bp->b_vp, B_READ, bp->b_data, ffs_fragstoblks(fs, blkno)))) {
brelse(bp, 0);
return (error);
}
/*
* Account for the block pointers in this indirect block.
*/
last = howmany(remblks, blksperindir);
if (last > FFS_NINDIR(fs))
last = FFS_NINDIR(fs);
bap = malloc(fs->fs_bsize, M_DEVBUF, M_WAITOK | M_ZERO);
memcpy((void *)bap, bp->b_data, fs->fs_bsize);
brelse(bp, 0);
error = (*acctfunc)(snapvp, bap, 0, 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 / FFS_NINDIR(fs);
for (lbn++, level--, i = 0; i < last; i++) {
error = indiracct(snapvp, cancelvp, level,
idb_get(VTOI(snapvp), bap, i), 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(struct vnode *vp, void *bap, int oldblkp, int lastblkp,
struct fs *fs, daddr_t lblkno,
int exptype /* BLK_SNAP or BLK_NOCOPY */)
{
int error;
if ((error = snapacct(vp, bap, oldblkp, lastblkp, fs, lblkno, exptype)))
return (error);
return (mapacct(vp, bap, oldblkp, lastblkp, fs, lblkno, exptype));
}
/*
* Identify a set of blocks allocated in a snapshot inode.
*/
static int
snapacct(struct vnode *vp, void *bap, int oldblkp, int lastblkp,
struct fs *fs, daddr_t lblkno,
int expungetype /* BLK_SNAP or BLK_NOCOPY */)
{
struct inode *ip = VTOI(vp);
struct lwp *l = curlwp;
struct mount *mp = vp->v_mount;
daddr_t blkno;
daddr_t lbn;
struct buf *ibp;
int error, n;
const int wbreak = blocks_in_journal(VFSTOUFS(mp)->um_fs)/8;
error = UFS_WAPBL_BEGIN(mp);
if (error)
return error;
for ( n = 0; oldblkp < lastblkp; oldblkp++) {
blkno = idb_get(ip, bap, oldblkp);
if (blkno == 0 || blkno == BLK_NOCOPY || blkno == BLK_SNAP)
continue;
lbn = ffs_fragstoblks(fs, blkno);
if (lbn < UFS_NDADDR) {
blkno = db_get(ip, lbn);
ip->i_flag |= IN_CHANGE | IN_UPDATE;
} else {
error = ffs_balloc(vp, ffs_lblktosize(fs, (off_t)lbn),
fs->fs_bsize, l->l_cred, B_METAONLY, &ibp);
if (error)
break;
blkno = idb_get(ip, ibp->b_data,
(lbn - UFS_NDADDR) % FFS_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.
*/
if (expungetype == BLK_SNAP && blkno == BLK_NOCOPY) {
if (lbn >= UFS_NDADDR)
brelse(ibp, 0);
} else {
if (blkno != 0)
panic("snapacct: bad block");
if (lbn < UFS_NDADDR)
db_assign(ip, lbn, expungetype);
else {
idb_assign(ip, ibp->b_data,
(lbn - UFS_NDADDR) % FFS_NINDIR(fs), expungetype);
bdwrite(ibp);
}
}
if (wbreak > 0 && (++n % wbreak) == 0) {
UFS_WAPBL_END(mp);
error = UFS_WAPBL_BEGIN(mp);
if (error)
return error;
}
}
UFS_WAPBL_END(mp);
return error;
}
/*
* Account for a set of blocks allocated in a snapshot inode.
*/
static int
mapacct(struct vnode *vp, void *bap, int oldblkp, int lastblkp,
struct fs *fs, daddr_t lblkno, int expungetype)
{
daddr_t blkno;
struct inode *ip;
struct mount *mp = vp->v_mount;
ino_t inum;
int acctit, error, n;
const int wbreak = blocks_in_journal(VFSTOUFS(mp)->um_fs)/8;
error = UFS_WAPBL_BEGIN(mp);
if (error)
return error;
ip = VTOI(vp);
inum = ip->i_number;
if (lblkno == -1)
acctit = 0;
else
acctit = 1;
for ( n = 0; oldblkp < lastblkp; oldblkp++, lblkno++) {
blkno = idb_get(ip, bap, oldblkp);
if (blkno == 0 || blkno == BLK_NOCOPY)
continue;
if (acctit && expungetype == BLK_SNAP && blkno != BLK_SNAP)
*ip->i_snapblklist++ = lblkno;
if (blkno == BLK_SNAP)
blkno = ffs_blkstofrags(fs, lblkno);
ffs_blkfree_snap(fs, vp, blkno, fs->fs_bsize, inum);
if (wbreak > 0 && (++n % wbreak) == 0) {
UFS_WAPBL_END(mp);
error = UFS_WAPBL_BEGIN(mp);
if (error)
return error;
}
}
UFS_WAPBL_END(mp);
return (0);
}
/*
* Number of blocks that fit into the journal or zero if not logging.
*/
static int
blocks_in_journal(struct fs *fs)
{
off_t bpj;
if ((fs->fs_flags & FS_DOWAPBL) == 0)
return 0;
bpj = 1;
if (fs->fs_journal_version == UFS_WAPBL_VERSION) {
switch (fs->fs_journal_location) {
case UFS_WAPBL_JOURNALLOC_END_PARTITION:
bpj = (off_t)fs->fs_journallocs[UFS_WAPBL_EPART_BLKSZ]*
fs->fs_journallocs[UFS_WAPBL_EPART_COUNT];
break;
case UFS_WAPBL_JOURNALLOC_IN_FILESYSTEM:
bpj = (off_t)fs->fs_journallocs[UFS_WAPBL_INFS_BLKSZ]*
fs->fs_journallocs[UFS_WAPBL_INFS_COUNT];
break;
}
}
bpj /= fs->fs_bsize;
return (bpj > 0 ? bpj : 1);
}
#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 vnode *vp)
{
struct inode *xp, *ip = VTOI(vp);
struct mount *mp = spec_node_getmountedfs(ip->i_devvp);
struct fs *fs;
struct snap_info *si;
int snaploc;
si = VFSTOUFS(mp)->um_snapinfo;
/*
* 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 = spec_node_getmountedfs(devvp);
struct buf *ibp;
struct snap_info *si;
struct lwp *l = curlwp;
daddr_t numblks, blkno, dblk;
int error, loc, last;
si = VFSTOUFS(mp)->um_snapinfo;
/*
* 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.
*/
mutex_enter(&si->si_snaplock);
mutex_enter(&si->si_lock);
if (is_active_snapshot(si, ip)) {
TAILQ_REMOVE(&si->si_snapshots, ip, i_nextsnap);
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;
si->si_gen++;
mutex_exit(&si->si_lock);
mutex_exit(&si->si_snaplock);
} else {
si->si_snapblklist = 0;
si->si_gen++;
mutex_exit(&si->si_lock);
mutex_exit(&si->si_snaplock);
fscow_disestablish(mp, ffs_copyonwrite, devvp);
}
if (ip->i_snapblklist != NULL) {
free(ip->i_snapblklist, M_UFSMNT);
ip->i_snapblklist = NULL;
}
} else {
mutex_exit(&si->si_lock);
mutex_exit(&si->si_snaplock);
}
/*
* Clear all BLK_NOCOPY fields. Pass any block claims to other
* snapshots that want them (see ffs_snapblkfree below).
*/
for (blkno = 1; blkno < UFS_NDADDR; blkno++) {
dblk = db_get(ip, blkno);
if (dblk == BLK_NOCOPY || dblk == BLK_SNAP)
db_assign(ip, blkno, 0);
else if ((dblk == ffs_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 = UFS_NDADDR; blkno < numblks; blkno += FFS_NINDIR(fs)) {
error = ffs_balloc(vp, ffs_lblktosize(fs, (off_t)blkno),
fs->fs_bsize, l->l_cred, B_METAONLY, &ibp);
if (error)
continue;
if (fs->fs_size - blkno > FFS_NINDIR(fs))
last = FFS_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 == ffs_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);
UFS_WAPBL_END(mp);
error = UFS_WAPBL_BEGIN(mp);
KASSERT(error == 0);
}
/*
* Clear snapshot flag and drop reference.
*/
ip->i_flags &= ~(SF_SNAPSHOT | SF_SNAPINVAL);
DIP_ASSIGN(ip, flags, ip->i_flags);
ip->i_flag |= IN_CHANGE | IN_UPDATE;
#if defined(QUOTA) || defined(QUOTA2)
chkdq(ip, DIP(ip, blocks), l->l_cred, FORCE);
chkiq(ip, 1, l->l_cred, FORCE);
#endif
}
/*
* 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, daddr_t bno,
long size, ino_t inum)
{
struct mount *mp = spec_node_getmountedfs(devvp);
struct buf *ibp;
struct inode *ip;
struct vnode *vp = NULL;
struct snap_info *si;
void *saved_data = NULL;
daddr_t lbn;
daddr_t blkno;
uint32_t gen;
int indiroff = 0, error = 0, claimedblk = 0;
si = VFSTOUFS(mp)->um_snapinfo;
lbn = ffs_fragstoblks(fs, bno);
mutex_enter(&si->si_snaplock);
mutex_enter(&si->si_lock);
si->si_owner = curlwp;
retry:
gen = si->si_gen;
TAILQ_FOREACH(ip, &si->si_snapshots, i_nextsnap) {
vp = ITOV(ip);
/*
* Lookup block being written.
*/
if (lbn < UFS_NDADDR) {
blkno = db_get(ip, lbn);
} else {
mutex_exit(&si->si_lock);
error = ffs_balloc(vp, ffs_lblktosize(fs, (off_t)lbn),
fs->fs_bsize, FSCRED, B_METAONLY, &ibp);
if (error) {
mutex_enter(&si->si_lock);
break;
}
indiroff = (lbn - UFS_NDADDR) % FFS_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 < UFS_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);
if (ip->i_nlink > 0)
bwrite(ibp);
else
bdwrite(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 >= UFS_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 < UFS_NDADDR) {
db_assign(ip, lbn, bno);
} else {
idb_assign(ip, ibp->b_data, indiroff, bno);
if (ip->i_nlink > 0)
bwrite(ibp);
else
bdwrite(ibp);
}
DIP_ADD(ip, blocks, btodb(size));
ip->i_flag |= IN_CHANGE | IN_UPDATE;
if (ip->i_nlink > 0 && mp->mnt_wapbl)
error = syncsnap(vp);
else
error = 0;
mutex_enter(&si->si_lock);
si->si_owner = NULL;
mutex_exit(&si->si_lock);
mutex_exit(&si->si_snaplock);
return (error == 0);
}
if (lbn >= UFS_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);
error = rwfsblk(vp, B_READ, saved_data, lbn);
if (error) {
free(saved_data, M_UFSMNT);
saved_data = NULL;
mutex_enter(&si->si_lock);
break;
}
}
error = wrsnapblk(vp, saved_data, lbn);
if (error == 0 && ip->i_nlink > 0 && mp->mnt_wapbl)
error = syncsnap(vp);
mutex_enter(&si->si_lock);
if (error)
break;
if (gen != si->si_gen)
goto retry;
}
si->si_owner = NULL;
mutex_exit(&si->si_lock);
mutex_exit(&si->si_snaplock);
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.
*/
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;
daddr_t snaplistsize, *snapblklist;
int i, error, ns __unused, snaploc, loc;
/*
* No persistent snapshots on apple ufs file systems.
*/
if (UFS_MPISAPPLEUFS(VFSTOUFS(mp)))
return;
si = VFSTOUFS(mp)->um_snapinfo;
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],
LK_EXCLUSIVE, &vp)) != 0) {
printf("ffs_snapshot_mount: vget failed %d\n", error);
continue;
}
ip = VTOI(vp);
if ((ip->i_flags & (SF_SNAPSHOT | SF_SNAPINVAL)) !=
SF_SNAPSHOT) {
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),
ffs_lblktosize(fs, howmany(fs->fs_size, fs->fs_frag)),
UIO_SYSSPACE, IO_NODELOCKED|IO_UNIT|IO_ALTSEMANTICS,
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(daddr_t), M_UFSMNT, M_WAITOK);
if (error)
snapblklist[0] = 1;
else {
error = vn_rdwr(UIO_READ, vp, (void *)snapblklist,
snaplistsize * sizeof(daddr_t),
ffs_lblktosize(fs, howmany(fs->fs_size, fs->fs_frag)),
UIO_SYSSPACE, IO_NODELOCKED|IO_UNIT|IO_ALTSEMANTICS,
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];
/*
* Link it onto the active snapshot list.
*/
if (is_active_snapshot(si, ip))
panic("ffs_snapshot_mount: %"PRIu64" already on list",
ip->i_number);
else
TAILQ_INSERT_TAIL(&si->si_snapshots, ip, i_nextsnap);
vp->v_vflag |= VV_SYSTEM;
VOP_UNLOCK(vp);
}
/*
* 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;
si = VFSTOUFS(mp)->um_snapinfo;
mutex_enter(&si->si_lock);
while ((xp = TAILQ_FIRST(&si->si_snapshots)) != 0) {
vp = ITOV(xp);
TAILQ_REMOVE(&si->si_snapshots, xp, i_nextsnap);
if (xp->i_snapblklist == si->si_snapblklist)
si->si_snapblklist = NULL;
free(xp->i_snapblklist, M_UFSMNT);
if (xp->i_nlink > 0) {
si->si_gen++;
mutex_exit(&si->si_lock);
vrele(vp);
mutex_enter(&si->si_lock);
}
}
si->si_gen++;
mutex_exit(&si->si_lock);
if (vp)
fscow_disestablish(mp, ffs_copyonwrite, devvp);
}
/*
* 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 fs *fs;
struct inode *ip;
struct vnode *devvp = v, *vp = NULL;
struct mount *mp = spec_node_getmountedfs(devvp);
struct snap_info *si;
void *saved_data = NULL;
daddr_t lbn, blkno, *snapblklist;
uint32_t gen;
int lower, upper, mid, snapshot_locked = 0, error = 0;
/*
* Check for valid snapshots.
*/
si = VFSTOUFS(mp)->um_snapinfo;
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 after the file system,
* in the journal or in the preallocated list.
* By doing these checks we avoid several potential deadlocks.
*/
fs = ip->i_fs;
lbn = ffs_fragstoblks(fs, FFS_DBTOFSB(fs, bp->b_blkno));
if (bp->b_blkno >= FFS_FSBTODB(fs, fs->fs_size)) {
mutex_exit(&si->si_lock);
return 0;
}
if ((fs->fs_flags & FS_DOWAPBL) &&
fs->fs_journal_location == UFS_WAPBL_JOURNALLOC_IN_FILESYSTEM) {
off_t blk_off, log_start, log_end;
log_start = (off_t)fs->fs_journallocs[UFS_WAPBL_INFS_ADDR] *
fs->fs_journallocs[UFS_WAPBL_INFS_BLKSZ];
log_end = log_start + fs->fs_journallocs[UFS_WAPBL_INFS_COUNT] *
fs->fs_journallocs[UFS_WAPBL_INFS_BLKSZ];
blk_off = dbtob(bp->b_blkno);
if (blk_off >= log_start && blk_off < log_end) {
mutex_exit(&si->si_lock);
return 0;
}
}
snapblklist = si->si_snapblklist;
upper = (snapblklist != NULL ? snapblklist[0] - 1 : 0);
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 (si->si_owner != curlwp) {
if (!mutex_tryenter(&si->si_snaplock)) {
mutex_exit(&si->si_lock);
mutex_enter(&si->si_snaplock);
mutex_enter(&si->si_lock);
}
si->si_owner = curlwp;
snapshot_locked = 1;
}
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;
/*
* Check to see if block needs to be copied.
*/
if (lbn < UFS_NDADDR) {
blkno = db_get(ip, lbn);
} else {
mutex_exit(&si->si_lock);
blkno = 0; /* XXX: GCC */
if ((error = snapblkaddr(vp, lbn, &blkno)) != 0) {
mutex_enter(&si->si_lock);
break;
}
mutex_enter(&si->si_lock);
if (gen != si->si_gen)
goto retry;
}
KASSERTMSG((blkno != BLK_SNAP || bp->b_lblkno < 0),
"ffs_copyonwrite: bad copy block: blkno %jd, lblkno %jd",
(intmax_t)blkno, (intmax_t)bp->b_lblkno);
if (blkno != 0)
continue;
if (curlwp == uvm.pagedaemon_lwp) {
error = ENOMEM;
break;
}
/* Only one level of recursion allowed. */
KASSERT(snapshot_locked);
/*
* 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);
error = rwfsblk(vp, B_READ, saved_data, lbn);
if (error) {
free(saved_data, M_UFSMNT);
saved_data = NULL;
mutex_enter(&si->si_lock);
break;
}
}
error = wrsnapblk(vp, saved_data, lbn);
if (error == 0 && ip->i_nlink > 0 && mp->mnt_wapbl)
error = syncsnap(vp);
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.
*/
if (snapshot_locked) {
si->si_owner = NULL;
mutex_exit(&si->si_lock);
mutex_exit(&si->si_snaplock);
} else
mutex_exit(&si->si_lock);
if (saved_data && saved_data != bp->b_data)
free(saved_data, M_UFSMNT);
return error;
}
/*
* Read from a snapshot.
*/
int
ffs_snapshot_read(struct vnode *vp, struct uio *uio, int ioflag)
{
struct inode *ip = VTOI(vp);
struct fs *fs = ip->i_fs;
struct snap_info *si = VFSTOUFS(vp->v_mount)->um_snapinfo;
struct buf *bp;
daddr_t lbn, nextlbn;
off_t fsbytes, bytesinfile;
long size, xfersize, blkoffset;
int error;
mutex_enter(&si->si_snaplock);
if (ioflag & IO_ALTSEMANTICS)
fsbytes = ip->i_size;
else
fsbytes = ffs_lfragtosize(fs, fs->fs_size);
for (error = 0, bp = NULL; uio->uio_resid > 0; bp = NULL) {
bytesinfile = fsbytes - uio->uio_offset;
if (bytesinfile <= 0)
break;
lbn = ffs_lblkno(fs, uio->uio_offset);
nextlbn = lbn + 1;
size = fs->fs_bsize;
blkoffset = ffs_blkoff(fs, uio->uio_offset);
xfersize = MIN(MIN(fs->fs_bsize - blkoffset, uio->uio_resid),
bytesinfile);
if (ffs_lblktosize(fs, nextlbn + 1) >= fsbytes) {
if (ffs_lblktosize(fs, lbn) + size > fsbytes)
size = ffs_fragroundup(fs,
fsbytes - ffs_lblktosize(fs, lbn));
error = bread(vp, lbn, size, 0, &bp);
} else {
int nextsize = fs->fs_bsize;
error = breadn(vp, lbn,
size, &nextlbn, &nextsize, 1, 0, &bp);
}
if (error)
break;
/*
* We should only get non-zero b_resid when an I/O error
* has occurred, which should cause us to break above.
* However, if the short read did not cause an error,
* then we want to ensure that we do not uiomove bad
* or uninitialized data.
*/
size -= bp->b_resid;
if (size < blkoffset + xfersize) {
xfersize = size - blkoffset;
if (xfersize <= 0)
break;
}
error = uiomove((char *)bp->b_data + blkoffset, xfersize, uio);
if (error)
break;
brelse(bp, BC_AGE);
}
if (bp != NULL)
brelse(bp, BC_AGE);
mutex_exit(&si->si_snaplock);
return error;
}
/*
* Lookup a snapshots data block address.
* Simpler than UFS_BALLOC() as we know all metadata is already allocated
* and safe even for the pagedaemon where we cannot bread().
*/
static int
snapblkaddr(struct vnode *vp, daddr_t lbn, daddr_t *res)
{
struct indir indirs[UFS_NIADDR + 2];
struct inode *ip = VTOI(vp);
struct fs *fs = ip->i_fs;
struct buf *bp;
int error, num;
KASSERT(lbn >= 0);
if (lbn < UFS_NDADDR) {
*res = db_get(ip, lbn);
return 0;
}
if ((error = ufs_getlbns(vp, lbn, indirs, &num)) != 0)
return error;
if (curlwp == uvm.pagedaemon_lwp) {
mutex_enter(&bufcache_lock);
bp = incore(vp, indirs[num-1].in_lbn);
if (bp && (bp->b_oflags & (BO_DONE | BO_DELWRI))) {
*res = idb_get(ip, bp->b_data, indirs[num-1].in_off);
error = 0;
} else
error = ENOMEM;
mutex_exit(&bufcache_lock);
return error;
}
error = bread(vp, indirs[num-1].in_lbn, fs->fs_bsize, 0, &bp);
if (error == 0) {
*res = idb_get(ip, bp->b_data, indirs[num-1].in_off);
brelse(bp, 0);
}
return error;
}
/*
* Read or write the specified block of the filesystem vp resides on
* from or to the disk bypassing the buffer cache.
*/
static int
rwfsblk(struct vnode *vp, int flags, void *data, daddr_t lbn)
{
int error;
struct inode *ip = VTOI(vp);
struct fs *fs = ip->i_fs;
struct buf *nbp;
nbp = getiobuf(NULL, true);
nbp->b_flags = flags;
nbp->b_bcount = nbp->b_bufsize = fs->fs_bsize;
nbp->b_error = 0;
nbp->b_data = data;
nbp->b_blkno = nbp->b_rawblkno = FFS_FSBTODB(fs, ffs_blkstofrags(fs, lbn));
nbp->b_proc = NULL;
nbp->b_dev = ip->i_devvp->v_rdev;
SET(nbp->b_cflags, BC_BUSY); /* mark buffer busy */
bdev_strategy(nbp);
error = biowait(nbp);
putiobuf(nbp);
return error;
}
/*
* Write all dirty buffers to disk and invalidate them.
*/
static int
syncsnap(struct vnode *vp)
{
int error;
buf_t *bp;
struct fs *fs = VTOI(vp)->i_fs;
mutex_enter(&bufcache_lock);
while ((bp = LIST_FIRST(&vp->v_dirtyblkhd))) {
error = bbusy(bp, false, 0, NULL);
if (error == EPASSTHROUGH)
continue;
else if (error != 0) {
mutex_exit(&bufcache_lock);
return error;
}
KASSERT(bp->b_bcount == fs->fs_bsize);
mutex_exit(&bufcache_lock);
error = rwfsblk(vp, B_WRITE, bp->b_data,
ffs_fragstoblks(fs, FFS_DBTOFSB(fs, bp->b_blkno)));
brelse(bp, BC_INVAL | BC_VFLUSH);
if (error)
return error;
mutex_enter(&bufcache_lock);
}
mutex_exit(&bufcache_lock);
return 0;
}
/*
* Write the specified block to a snapshot.
*/
static int
wrsnapblk(struct vnode *vp, void *data, daddr_t lbn)
{
struct inode *ip = VTOI(vp);
struct fs *fs = ip->i_fs;
struct buf *bp;
int error;
error = ffs_balloc(vp, ffs_lblktosize(fs, (off_t)lbn), fs->fs_bsize,
FSCRED, (ip->i_nlink > 0 ? B_SYNC : 0), &bp);
if (error)
return error;
memcpy(bp->b_data, data, fs->fs_bsize);
if (ip->i_nlink > 0)
error = bwrite(bp);
else
bawrite(bp);
return error;
}
/*
* Check if this inode is present on the active snapshot list.
* Must be called with snapinfo locked.
*/
static inline bool
is_active_snapshot(struct snap_info *si, struct inode *ip)
{
struct inode *xp;
KASSERT(mutex_owned(&si->si_lock));
TAILQ_FOREACH(xp, &si->si_snapshots, i_nextsnap)
if (xp == ip)
return true;
return false;
}
/*
* 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 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, 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));
}
__unused static inline daddr_t
ib_get(struct inode *ip, int loc)
{
if (ip->i_ump->um_fstype == UFS1)
return ufs_rw32(ip->i_ffs1_ib[loc], UFS_IPNEEDSWAP(ip));
else
return ufs_rw64(ip->i_ffs2_ib[loc], UFS_IPNEEDSWAP(ip));
}
static inline daddr_t
idb_get(struct inode *ip, void *bf, int loc)
{
if (ip->i_ump->um_fstype == UFS1)
return ufs_rw32(((int32_t *)(bf))[loc], UFS_IPNEEDSWAP(ip));
else
return ufs_rw64(((int64_t *)(bf))[loc], UFS_IPNEEDSWAP(ip));
}
static inline void
idb_assign(struct inode *ip, void *bf, int loc, daddr_t val)
{
if (ip->i_ump->um_fstype == UFS1)
((int32_t *)(bf))[loc] = ufs_rw32(val, UFS_IPNEEDSWAP(ip));
else
((int64_t *)(bf))[loc] = ufs_rw64(val, UFS_IPNEEDSWAP(ip));
}
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