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freebsd-skq/sys/ufs/ffs/ffs_snapshot.c
Konstantin Belousov f99cb34c4f The process_deferred_inactive() function locks the vnodes of the ufs 
mount, which means that is must not be called while the snaplock is
owned.  The vfs_write_resume(9) does call the function as the
VFS_SUSP_CLEAN() method, which is too early and falls into the region
still protected by snaplock.

Add yet another flag for the vfs_write_resume_flags() to avoid calling
suspension cleanup handler after the suspend is lifted, and use it in
the ffs_snapshot() call to vfs_write_resume.

Reported and tested by:	pho
Sponsored by:	The FreeBSD Foundation
MFC after:	2 weeks
2013-01-01 16:14:48 +00:00

2678 lines
73 KiB
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/*-
* 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
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_quota.h"
#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/systm.h>
#include <sys/conf.h>
#include <sys/bio.h>
#include <sys/buf.h>
#include <sys/fcntl.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 <geom/geom.h>
#include <ufs/ufs/extattr.h>
#include <ufs/ufs/quota.h>
#include <ufs/ufs/ufsmount.h>
#include <ufs/ufs/inode.h>
#include <ufs/ufs/ufs_extern.h>
#include <ufs/ffs/fs.h>
#include <ufs/ffs/ffs_extern.h>
#define KERNCRED thread0.td_ucred
#define DEBUG 1
#include "opt_ffs.h"
#ifdef NO_FFS_SNAPSHOT
int
ffs_snapshot(mp, snapfile)
struct mount *mp;
char *snapfile;
{
return (EINVAL);
}
int
ffs_snapblkfree(fs, devvp, bno, size, inum, vtype, wkhd)
struct fs *fs;
struct vnode *devvp;
ufs2_daddr_t bno;
long size;
ino_t inum;
enum vtype vtype;
struct workhead *wkhd;
{
return (EINVAL);
}
void
ffs_snapremove(vp)
struct vnode *vp;
{
}
void
ffs_snapshot_mount(mp)
struct mount *mp;
{
}
void
ffs_snapshot_unmount(mp)
struct mount *mp;
{
}
void
ffs_snapgone(ip)
struct inode *ip;
{
}
int
ffs_copyonwrite(devvp, bp)
struct vnode *devvp;
struct buf *bp;
{
return (EINVAL);
}
void
ffs_sync_snap(mp, waitfor)
struct mount *mp;
int waitfor;
{
}
#else
FEATURE(ffs_snapshot, "FFS snapshot support");
LIST_HEAD(, snapdata) snapfree;
static struct mtx snapfree_lock;
MTX_SYSINIT(ffs_snapfree, &snapfree_lock, "snapdata free list", MTX_DEF);
static int cgaccount(int, struct vnode *, struct buf *, 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, 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, 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 readblock(struct vnode *vp, struct buf *, ufs2_daddr_t);
static void try_free_snapdata(struct vnode *devvp);
static struct snapdata *ffs_snapdata_acquire(struct vnode *devvp);
static int ffs_bp_snapblk(struct vnode *, struct buf *);
/*
* To ensure the consistency of snapshots across crashes, we must
* synchronously write out copied blocks before allowing the
* originals to be modified. Because of the rather severe speed
* penalty that this imposes, the code normally only ensures
* persistence for the filesystem metadata contained within a
* snapshot. Setting the following flag allows this crash
* persistence to be enabled for file contents.
*/
int dopersistence = 0;
#ifdef DEBUG
#include <sys/sysctl.h>
SYSCTL_INT(_debug, OID_AUTO, dopersistence, CTLFLAG_RW, &dopersistence, 0, "");
static int snapdebug = 0;
SYSCTL_INT(_debug, OID_AUTO, snapdebug, CTLFLAG_RW, &snapdebug, 0, "");
int collectsnapstats = 0;
SYSCTL_INT(_debug, OID_AUTO, collectsnapstats, CTLFLAG_RW, &collectsnapstats,
0, "");
#endif /* DEBUG */
/*
* Create a snapshot file and initialize it for the filesystem.
*/
int
ffs_snapshot(mp, snapfile)
struct mount *mp;
char *snapfile;
{
ufs2_daddr_t numblks, blkno, *blkp, *snapblklist;
int error, cg, snaploc;
int i, size, len, loc;
ufs2_daddr_t blockno;
uint64_t flag;
struct timespec starttime = {0, 0}, endtime;
char saved_nice = 0;
long redo = 0, snaplistsize = 0;
int32_t *lp;
void *space;
struct fs *copy_fs = NULL, *fs;
struct thread *td = curthread;
struct inode *ip, *xp;
struct buf *bp, *nbp, *ibp;
struct nameidata nd;
struct mount *wrtmp;
struct vattr vat;
struct vnode *vp, *xvp, *mvp, *devvp;
struct uio auio;
struct iovec aiov;
struct snapdata *sn;
struct ufsmount *ump;
ump = VFSTOUFS(mp);
fs = ump->um_fs;
sn = NULL;
/*
* At the moment, journaled soft updates cannot support
* taking snapshots.
*/
if (MOUNTEDSUJ(mp)) {
vfs_mount_error(mp, "%s: Snapshots are not yet supported when "
"running with journaled soft updates", fs->fs_fsmnt);
return (EOPNOTSUPP);
}
MNT_ILOCK(mp);
flag = mp->mnt_flag;
MNT_IUNLOCK(mp);
/*
* Need to serialize access to snapshot code per filesystem.
*/
/*
* Assign a snapshot slot in the superblock.
*/
UFS_LOCK(ump);
for (snaploc = 0; snaploc < FSMAXSNAP; snaploc++)
if (fs->fs_snapinum[snaploc] == 0)
break;
UFS_UNLOCK(ump);
if (snaploc == FSMAXSNAP)
return (ENOSPC);
/*
* Create the snapshot file.
*/
restart:
NDINIT(&nd, CREATE, LOCKPARENT | LOCKLEAF, UIO_SYSSPACE, snapfile, td);
if ((error = namei(&nd)) != 0)
return (error);
if (nd.ni_vp != NULL) {
vput(nd.ni_vp);
error = EEXIST;
}
if (nd.ni_dvp->v_mount != mp)
error = EXDEV;
if (error) {
NDFREE(&nd, NDF_ONLY_PNBUF);
if (nd.ni_dvp == nd.ni_vp)
vrele(nd.ni_dvp);
else
vput(nd.ni_dvp);
return (error);
}
VATTR_NULL(&vat);
vat.va_type = VREG;
vat.va_mode = S_IRUSR;
vat.va_vaflags |= VA_EXCLUSIVE;
if (VOP_GETWRITEMOUNT(nd.ni_dvp, &wrtmp))
wrtmp = NULL;
if (wrtmp != mp)
panic("ffs_snapshot: mount mismatch");
vfs_rel(wrtmp);
if (vn_start_write(NULL, &wrtmp, V_NOWAIT) != 0) {
NDFREE(&nd, NDF_ONLY_PNBUF);
vput(nd.ni_dvp);
if ((error = vn_start_write(NULL, &wrtmp,
V_XSLEEP | PCATCH)) != 0)
return (error);
goto restart;
}
error = VOP_CREATE(nd.ni_dvp, &nd.ni_vp, &nd.ni_cnd, &vat);
VOP_UNLOCK(nd.ni_dvp, 0);
if (error) {
NDFREE(&nd, NDF_ONLY_PNBUF);
vn_finished_write(wrtmp);
vrele(nd.ni_dvp);
return (error);
}
vp = nd.ni_vp;
vp->v_vflag |= VV_SYSTEM;
ip = VTOI(vp);
devvp = ip->i_devvp;
/*
* Allocate and copy the last block contents so as to be able
* to set size to that of the filesystem.
*/
numblks = howmany(fs->fs_size, fs->fs_frag);
error = UFS_BALLOC(vp, lblktosize(fs, (off_t)(numblks - 1)),
fs->fs_bsize, KERNCRED, BA_CLRBUF, &bp);
if (error)
goto out;
ip->i_size = lblktosize(fs, (off_t)numblks);
DIP_SET(ip, i_size, ip->i_size);
ip->i_flag |= IN_CHANGE | IN_UPDATE;
error = readblock(vp, bp, numblks - 1);
bawrite(bp);
if (error != 0)
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 = UFS_BALLOC(vp, lblktosize(fs, (off_t)blkno),
fs->fs_bsize, td->td_ucred, BA_METAONLY, &ibp);
if (error)
goto out;
bawrite(ibp);
}
/*
* Allocate copies for the superblock and its summary information.
*/
error = UFS_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 = UFS_BALLOC(vp, lblktosize(fs, (off_t)(blkno + loc)),
fs->fs_bsize, KERNCRED, 0, &nbp);
if (error)
goto out;
bawrite(nbp);
}
/*
* Allocate all cylinder group blocks.
*/
for (cg = 0; cg < fs->fs_ncg; cg++) {
error = UFS_BALLOC(vp, lfragtosize(fs, cgtod(fs, cg)),
fs->fs_bsize, KERNCRED, 0, &nbp);
if (error)
goto out;
bawrite(nbp);
if (cg % 10 == 0)
ffs_syncvnode(vp, MNT_WAIT, 0);
}
/*
* 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);
space = malloc(len, M_DEVBUF, M_WAITOK|M_ZERO);
UFS_LOCK(ump);
fs->fs_active = space;
UFS_UNLOCK(ump);
for (cg = 0; cg < fs->fs_ncg; cg++) {
error = UFS_BALLOC(vp, lfragtosize(fs, cgtod(fs, cg)),
fs->fs_bsize, KERNCRED, 0, &nbp);
if (error)
goto out;
error = cgaccount(cg, vp, nbp, 1);
bawrite(nbp);
if (cg % 10 == 0)
ffs_syncvnode(vp, MNT_WAIT, 0);
if (error)
goto out;
}
/*
* Change inode to snapshot type file.
*/
ip->i_flags |= SF_SNAPSHOT;
DIP_SET(ip, i_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 = ffs_syncvnode(vp, MNT_WAIT, 0)) != 0)
goto out;
VOP_UNLOCK(vp, 0);
/*
* All allocations are done, so we can now snapshot the system.
*
* Recind nice scheduling while running with the filesystem suspended.
*/
if (td->td_proc->p_nice > 0) {
struct proc *p;
p = td->td_proc;
PROC_LOCK(p);
saved_nice = p->p_nice;
sched_nice(p, 0);
PROC_UNLOCK(p);
}
/*
* Suspend operation on filesystem.
*/
for (;;) {
vn_finished_write(wrtmp);
if ((error = vfs_write_suspend(vp->v_mount)) != 0) {
vn_start_write(NULL, &wrtmp, V_WAIT);
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
goto out;
}
if (mp->mnt_kern_flag & MNTK_SUSPENDED)
break;
vn_start_write(NULL, &wrtmp, V_WAIT);
}
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
if (ip->i_effnlink == 0) {
error = ENOENT; /* Snapshot file unlinked */
goto out1;
}
if (collectsnapstats)
nanotime(&starttime);
/* The last block might have changed. Copy it again to be sure. */
error = UFS_BALLOC(vp, lblktosize(fs, (off_t)(numblks - 1)),
fs->fs_bsize, KERNCRED, BA_CLRBUF, &bp);
if (error != 0)
goto out1;
error = readblock(vp, bp, numblks - 1);
bp->b_flags |= B_VALIDSUSPWRT;
bawrite(bp);
if (error != 0)
goto out1;
/*
* First, copy all the cylinder group maps that have changed.
*/
for (cg = 0; cg < fs->fs_ncg; cg++) {
if ((ACTIVECGNUM(fs, cg) & ACTIVECGOFF(cg)) != 0)
continue;
redo++;
error = UFS_BALLOC(vp, lfragtosize(fs, cgtod(fs, cg)),
fs->fs_bsize, KERNCRED, 0, &nbp);
if (error)
goto out1;
error = cgaccount(cg, vp, nbp, 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.
*/
copy_fs = malloc((u_long)fs->fs_bsize, M_UFSMNT, M_WAITOK);
bcopy(fs, copy_fs, fs->fs_sbsize);
if ((fs->fs_flags & (FS_UNCLEAN | FS_NEEDSFSCK)) == 0)
copy_fs->fs_clean = 1;
size = fs->fs_bsize < SBLOCKSIZE ? fs->fs_bsize : SBLOCKSIZE;
if (fs->fs_sbsize < size)
bzero(&((char *)copy_fs)[fs->fs_sbsize],
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);
free(copy_fs->fs_csp, M_UFSMNT);
free(copy_fs, M_UFSMNT);
copy_fs = NULL;
goto out1;
}
bcopy(bp->b_data, space, (u_int)len);
space = (char *)space + len;
bp->b_flags |= B_INVAL | B_NOCACHE;
brelse(bp);
}
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);
mp->mnt_kern_flag &= ~MNTK_SUSPENDED;
MNT_IUNLOCK(mp);
loop:
MNT_VNODE_FOREACH_ALL(xvp, mp, mvp) {
if ((xvp->v_usecount == 0 &&
(xvp->v_iflag & (VI_OWEINACT | VI_DOINGINACT)) == 0) ||
xvp->v_type == VNON ||
IS_SNAPSHOT(VTOI(xvp))) {
VI_UNLOCK(xvp);
continue;
}
/*
* We can skip parent directory vnode because it must have
* this snapshot file in it.
*/
if (xvp == nd.ni_dvp) {
VI_UNLOCK(xvp);
continue;
}
vholdl(xvp);
if (vn_lock(xvp, LK_EXCLUSIVE | LK_INTERLOCK) != 0) {
MNT_VNODE_FOREACH_ALL_ABORT(mp, mvp);
vdrop(xvp);
goto loop;
}
VI_LOCK(xvp);
if (xvp->v_usecount == 0 &&
(xvp->v_iflag & (VI_OWEINACT | VI_DOINGINACT)) == 0) {
VI_UNLOCK(xvp);
VOP_UNLOCK(xvp, 0);
vdrop(xvp);
continue;
}
VI_UNLOCK(xvp);
if (snapdebug)
vprint("ffs_snapshot: busy vnode", xvp);
if (VOP_GETATTR(xvp, &vat, td->td_ucred) == 0 &&
vat.va_nlink > 0) {
VOP_UNLOCK(xvp, 0);
vdrop(xvp);
continue;
}
xp = VTOI(xvp);
if (ffs_checkfreefile(copy_fs, vp, xp->i_number)) {
VOP_UNLOCK(xvp, 0);
vdrop(xvp);
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(ump, copy_fs, vp,
DIP(xp, i_db[loc]), len, xp->i_number,
xvp->v_type, NULL);
blkno = DIP(xp, i_db[loc]);
DIP_SET(xp, i_db[loc], 0);
}
}
snaplistsize += 1;
if (xp->i_ump->um_fstype == UFS1)
error = expunge_ufs1(vp, xp, copy_fs, fullacct_ufs1,
BLK_NOCOPY, 1);
else
error = expunge_ufs2(vp, xp, copy_fs, fullacct_ufs2,
BLK_NOCOPY, 1);
if (blkno)
DIP_SET(xp, i_db[loc], blkno);
if (!error)
error = ffs_freefile(ump, copy_fs, vp, xp->i_number,
xp->i_mode, NULL);
VOP_UNLOCK(xvp, 0);
vdrop(xvp);
if (error) {
free(copy_fs->fs_csp, M_UFSMNT);
free(copy_fs, M_UFSMNT);
copy_fs = NULL;
MNT_VNODE_FOREACH_ALL_ABORT(mp, mvp);
goto out1;
}
}
/*
* Erase the journal file from the snapshot.
*/
if (fs->fs_flags & FS_SUJ) {
error = softdep_journal_lookup(mp, &xvp);
if (error) {
free(copy_fs->fs_csp, M_UFSMNT);
free(copy_fs, M_UFSMNT);
copy_fs = NULL;
goto out1;
}
xp = VTOI(xvp);
if (xp->i_ump->um_fstype == UFS1)
error = expunge_ufs1(vp, xp, copy_fs, fullacct_ufs1,
BLK_NOCOPY, 0);
else
error = expunge_ufs2(vp, xp, copy_fs, fullacct_ufs2,
BLK_NOCOPY, 0);
vput(xvp);
}
/*
* Acquire a lock on the snapdata structure, creating it if necessary.
*/
sn = ffs_snapdata_acquire(devvp);
/*
* Change vnode to use shared snapshot lock instead of the original
* private lock.
*/
vp->v_vnlock = &sn->sn_lock;
lockmgr(&vp->v_lock, LK_RELEASE, NULL);
xp = TAILQ_FIRST(&sn->sn_head);
/*
* 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(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;
VI_LOCK(devvp);
if (sn->sn_blklist != NULL)
panic("ffs_snapshot: non-empty list");
sn->sn_blklist = snapblklist;
sn->sn_listsize = blkp - snapblklist;
VI_UNLOCK(devvp);
}
/*
* Record snapshot inode. Since this is the newest snapshot,
* it must be placed at the end of the list.
*/
VI_LOCK(devvp);
fs->fs_snapinum[snaploc] = ip->i_number;
if (ip->i_nextsnap.tqe_prev != 0)
panic("ffs_snapshot: %ju already on list",
(uintmax_t)ip->i_number);
TAILQ_INSERT_TAIL(&sn->sn_head, ip, i_nextsnap);
devvp->v_vflag |= VV_COPYONWRITE;
VI_UNLOCK(devvp);
ASSERT_VOP_LOCKED(vp, "ffs_snapshot vp");
out1:
KASSERT((sn != NULL && copy_fs != NULL && error == 0) ||
(sn == NULL && copy_fs == NULL && error != 0),
("email phk@ and mckusick@"));
/*
* Resume operation on filesystem.
*/
vfs_write_resume_flags(vp->v_mount, VR_START_WRITE | VR_NO_SUSPCLR);
if (collectsnapstats && starttime.tv_sec > 0) {
nanotime(&endtime);
timespecsub(&endtime, &starttime);
printf("%s: suspended %ld.%03ld sec, redo %ld of %d\n",
vp->v_mount->mnt_stat.f_mntonname, (long)endtime.tv_sec,
endtime.tv_nsec / 1000000, redo, fs->fs_ncg);
}
if (copy_fs == NULL)
goto out;
/*
* Copy allocation information from all the snapshots in
* this snapshot and then expunge them from its view.
*/
TAILQ_FOREACH(xp, &sn->sn_head, i_nextsnap) {
if (xp == ip)
break;
if (xp->i_ump->um_fstype == UFS1)
error = expunge_ufs1(vp, xp, fs, snapacct_ufs1,
BLK_SNAP, 0);
else
error = expunge_ufs2(vp, xp, fs, snapacct_ufs2,
BLK_SNAP, 0);
if (error == 0 && xp->i_effnlink == 0) {
error = ffs_freefile(ump,
copy_fs,
vp,
xp->i_number,
xp->i_mode, NULL);
}
if (error) {
fs->fs_snapinum[snaploc] = 0;
goto done;
}
}
/*
* Allocate space for the full list of preallocated snapshot blocks.
*/
snapblklist = malloc(snaplistsize * sizeof(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, 0);
else
error = expunge_ufs2(vp, ip, copy_fs, mapacct_ufs2,
BLK_SNAP, 0);
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 = 0;
/*
* Write out the list of allocated blocks to the end of the snapshot.
*/
auio.uio_iov = &aiov;
auio.uio_iovcnt = 1;
aiov.iov_base = (void *)snapblklist;
aiov.iov_len = snaplistsize * sizeof(daddr_t);
auio.uio_resid = aiov.iov_len;
auio.uio_offset = ip->i_size;
auio.uio_segflg = UIO_SYSSPACE;
auio.uio_rw = UIO_WRITE;
auio.uio_td = td;
if ((error = VOP_WRITE(vp, &auio, IO_UNIT, td->td_ucred)) != 0) {
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;
for (loc = 0; loc < len; loc++) {
error = bread(vp, blkno + loc, fs->fs_bsize, KERNCRED, &nbp);
if (error) {
brelse(nbp);
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);
}
error = bread(vp, lblkno(fs, fs->fs_sblockloc), fs->fs_bsize,
KERNCRED, &nbp);
if (error) {
brelse(nbp);
} else {
loc = blkoff(fs, fs->fs_sblockloc);
bcopy((char *)copy_fs, &nbp->b_data[loc], fs->fs_bsize);
bawrite(nbp);
}
/*
* As this is the newest list, it is the most inclusive, so
* should replace the previous list.
*/
VI_LOCK(devvp);
space = sn->sn_blklist;
sn->sn_blklist = snapblklist;
sn->sn_listsize = snaplistsize;
VI_UNLOCK(devvp);
if (space != NULL)
free(space, M_UFSMNT);
/*
* Preallocate all the direct blocks in the snapshot inode so
* that we never have to write the inode itself to commit an
* update to the contents of the snapshot. Note that once
* created, the size of the snapshot will never change, so
* there will never be a need to write the inode except to
* update the non-integrity-critical time fields and
* allocated-block count.
*/
for (blockno = 0; blockno < NDADDR; blockno++) {
if (DIP(ip, i_db[blockno]) != 0)
continue;
error = UFS_BALLOC(vp, lblktosize(fs, blockno),
fs->fs_bsize, KERNCRED, BA_CLRBUF, &bp);
if (error)
break;
error = readblock(vp, bp, blockno);
bawrite(bp);
if (error != 0)
break;
}
done:
free(copy_fs->fs_csp, M_UFSMNT);
free(copy_fs, M_UFSMNT);
copy_fs = NULL;
out:
NDFREE(&nd, NDF_ONLY_PNBUF);
if (saved_nice > 0) {
struct proc *p;
p = td->td_proc;
PROC_LOCK(p);
sched_nice(td->td_proc, saved_nice);
PROC_UNLOCK(td->td_proc);
}
UFS_LOCK(ump);
if (fs->fs_active != 0) {
free(fs->fs_active, M_DEVBUF);
fs->fs_active = 0;
}
UFS_UNLOCK(ump);
MNT_ILOCK(mp);
mp->mnt_flag = (mp->mnt_flag & MNT_QUOTA) | (flag & ~MNT_QUOTA);
MNT_IUNLOCK(mp);
if (error)
(void) ffs_truncate(vp, (off_t)0, 0, NOCRED);
(void) ffs_syncvnode(vp, MNT_WAIT, 0);
if (error)
vput(vp);
else
VOP_UNLOCK(vp, 0);
vrele(nd.ni_dvp);
vn_finished_write(wrtmp);
process_deferred_inactive(mp);
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(cg, vp, nbp, passno)
int cg;
struct vnode *vp;
struct buf *nbp;
int passno;
{
struct buf *bp, *ibp;
struct inode *ip;
struct cg *cgp;
struct fs *fs;
ufs2_daddr_t base, numblks;
int error, len, loc, indiroff;
ip = VTOI(vp);
fs = ip->i_fs;
error = bread(ip->i_devvp, fsbtodb(fs, cgtod(fs, cg)),
(int)fs->fs_cgsize, KERNCRED, &bp);
if (error) {
brelse(bp);
return (error);
}
cgp = (struct cg *)bp->b_data;
if (!cg_chkmagic(cgp)) {
brelse(bp);
return (EIO);
}
UFS_LOCK(ip->i_ump);
ACTIVESET(fs, cg);
/*
* Recomputation of summary information might not have been performed
* at mount time. Sync up summary information for current cylinder
* group while data is in memory to ensure that result of background
* fsck is slightly more consistent.
*/
fs->fs_cs(fs, cg) = cgp->cg_cs;
UFS_UNLOCK(ip->i_ump);
bcopy(bp->b_data, nbp->b_data, fs->fs_cgsize);
if (fs->fs_cgsize < fs->fs_bsize)
bzero(&nbp->b_data[fs->fs_cgsize],
fs->fs_bsize - fs->fs_cgsize);
cgp = (struct cg *)nbp->b_data;
bqrelse(bp);
if (passno == 2)
nbp->b_flags |= B_VALIDSUSPWRT;
numblks = howmany(fs->fs_size, fs->fs_frag);
len = howmany(fs->fs_fpg, fs->fs_frag);
base = cgbase(fs, cg) / 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), loc))
DIP_SET(ip, i_db[loc], BLK_NOCOPY);
else if (passno == 2 && DIP(ip, i_db[loc])== BLK_NOCOPY)
DIP_SET(ip, i_db[loc], 0);
else if (passno == 1 && DIP(ip, i_db[loc])== BLK_NOCOPY)
panic("ffs_snapshot: lost direct block");
}
}
error = UFS_BALLOC(vp, lblktosize(fs, (off_t)(base + loc)),
fs->fs_bsize, KERNCRED, BA_METAONLY, &ibp);
if (error) {
return (error);
}
indiroff = (base + loc - NDADDR) % NINDIR(fs);
for ( ; loc < len; loc++, indiroff++) {
if (indiroff >= NINDIR(fs)) {
if (passno == 2)
ibp->b_flags |= B_VALIDSUSPWRT;
bawrite(ibp);
error = UFS_BALLOC(vp,
lblktosize(fs, (off_t)(base + loc)),
fs->fs_bsize, KERNCRED, BA_METAONLY, &ibp);
if (error) {
return (error);
}
indiroff = 0;
}
if (ip->i_ump->um_fstype == UFS1) {
if (ffs_isblock(fs, cg_blksfree(cgp), loc))
((ufs1_daddr_t *)(ibp->b_data))[indiroff] =
BLK_NOCOPY;
else if (passno == 2 && ((ufs1_daddr_t *)(ibp->b_data))
[indiroff] == BLK_NOCOPY)
((ufs1_daddr_t *)(ibp->b_data))[indiroff] = 0;
else if (passno == 1 && ((ufs1_daddr_t *)(ibp->b_data))
[indiroff] == BLK_NOCOPY)
panic("ffs_snapshot: lost indirect block");
continue;
}
if (ffs_isblock(fs, cg_blksfree(cgp), loc))
((ufs2_daddr_t *)(ibp->b_data))[indiroff] = BLK_NOCOPY;
else if (passno == 2 &&
((ufs2_daddr_t *)(ibp->b_data)) [indiroff] == BLK_NOCOPY)
((ufs2_daddr_t *)(ibp->b_data))[indiroff] = 0;
else if (passno == 1 &&
((ufs2_daddr_t *)(ibp->b_data)) [indiroff] == BLK_NOCOPY)
panic("ffs_snapshot: lost indirect block");
}
if (passno == 2)
ibp->b_flags |= B_VALIDSUSPWRT;
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(snapvp, cancelip, fs, acctfunc, expungetype, clearmode)
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 clearmode;
{
int i, error, indiroff;
ufs_lbn_t lbn, rlbn;
ufs2_daddr_t len, blkno, numblks, blksperindir;
struct ufs1_dinode *dip;
struct thread *td = curthread;
struct buf *bp;
/*
* 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 = VTOI(snapvp)->i_din1->di_db[lbn];
} else {
if (DOINGSOFTDEP(snapvp))
softdep_prealloc(snapvp, MNT_WAIT);
td->td_pflags |= TDP_COWINPROGRESS;
error = ffs_balloc_ufs1(snapvp, lblktosize(fs, (off_t)lbn),
fs->fs_bsize, KERNCRED, BA_METAONLY, &bp);
td->td_pflags &= ~TDP_COWINPROGRESS;
if (error)
return (error);
indiroff = (lbn - NDADDR) % NINDIR(fs);
blkno = ((ufs1_daddr_t *)(bp->b_data))[indiroff];
bqrelse(bp);
}
if (blkno != 0) {
if ((error = bread(snapvp, lbn, fs->fs_bsize, KERNCRED, &bp)))
return (error);
} else {
error = ffs_balloc_ufs1(snapvp, lblktosize(fs, (off_t)lbn),
fs->fs_bsize, KERNCRED, 0, &bp);
if (error)
return (error);
if ((error = readblock(snapvp, bp, lbn)) != 0)
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 *)bp->b_data +
ino_to_fsbo(fs, cancelip->i_number);
if (clearmode || cancelip->i_effnlink == 0)
dip->di_mode = 0;
dip->di_size = 0;
dip->di_blocks = 0;
dip->di_flags &= ~SF_SNAPSHOT;
bzero(&dip->di_db[0], (NDADDR + NIADDR) * sizeof(ufs1_daddr_t));
bdwrite(bp);
/*
* 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_din1->di_db[0],
&cancelip->i_din1->di_db[NDADDR], fs, 0, expungetype)))
return (error);
if ((error = (*acctfunc)(snapvp, &cancelip->i_din1->di_ib[0],
&cancelip->i_din1->di_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,
cancelip->i_din1->di_ib[i], 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(snapvp, cancelvp, level, blkno, lbn, rlbn, remblks,
blksperindir, fs, acctfunc, expungetype)
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, num, i;
ufs_lbn_t subblksperindir;
struct indir indirs[NIADDR + 2];
ufs1_daddr_t last, *bap;
struct buf *bp;
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, 0);
bp->b_blkno = fsbtodb(fs, blkno);
if ((bp->b_flags & (B_DONE | B_DELWRI)) == 0 &&
(error = readblock(cancelvp, bp, fragstoblks(fs, blkno)))) {
brelse(bp);
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, (caddr_t)bap, fs->fs_bsize);
bqrelse(bp);
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, 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_ufs1(vp, oldblkp, lastblkp, fs, lblkno, exptype)
struct vnode *vp;
ufs1_daddr_t *oldblkp, *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(vp, oldblkp, lastblkp, fs, lblkno, expungetype)
struct vnode *vp;
ufs1_daddr_t *oldblkp, *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;
for ( ; oldblkp < lastblkp; oldblkp++) {
blkno = *oldblkp;
if (blkno == 0 || blkno == BLK_NOCOPY || blkno == BLK_SNAP)
continue;
lbn = fragstoblks(fs, blkno);
if (lbn < NDADDR) {
blkp = &ip->i_din1->di_db[lbn];
ip->i_flag |= IN_CHANGE | IN_UPDATE;
} else {
error = ffs_balloc_ufs1(vp, lblktosize(fs, (off_t)lbn),
fs->fs_bsize, KERNCRED, BA_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.
*/
if (expungetype == BLK_SNAP && *blkp == BLK_NOCOPY) {
if (lbn >= NDADDR)
brelse(ibp);
} else {
if (*blkp != 0)
panic("snapacct_ufs1: bad block");
*blkp = expungetype;
if (lbn >= NDADDR)
bdwrite(ibp);
}
}
return (0);
}
/*
* Account for a set of blocks allocated in a snapshot inode.
*/
static int
mapacct_ufs1(vp, oldblkp, lastblkp, fs, lblkno, expungetype)
struct vnode *vp;
ufs1_daddr_t *oldblkp, *lastblkp;
struct fs *fs;
ufs_lbn_t lblkno;
int expungetype;
{
ufs1_daddr_t blkno;
struct inode *ip;
ino_t inum;
int acctit;
ip = VTOI(vp);
inum = ip->i_number;
if (lblkno == -1)
acctit = 0;
else
acctit = 1;
for ( ; oldblkp < lastblkp; oldblkp++, lblkno++) {
blkno = *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 = blkstofrags(fs, lblkno);
ffs_blkfree(ip->i_ump, fs, vp, blkno, fs->fs_bsize, inum,
vp->v_type, NULL);
}
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(snapvp, cancelip, fs, acctfunc, expungetype, clearmode)
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 clearmode;
{
int i, error, indiroff;
ufs_lbn_t lbn, rlbn;
ufs2_daddr_t len, blkno, numblks, blksperindir;
struct ufs2_dinode *dip;
struct thread *td = curthread;
struct buf *bp;
/*
* 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 = VTOI(snapvp)->i_din2->di_db[lbn];
} else {
if (DOINGSOFTDEP(snapvp))
softdep_prealloc(snapvp, MNT_WAIT);
td->td_pflags |= TDP_COWINPROGRESS;
error = ffs_balloc_ufs2(snapvp, lblktosize(fs, (off_t)lbn),
fs->fs_bsize, KERNCRED, BA_METAONLY, &bp);
td->td_pflags &= ~TDP_COWINPROGRESS;
if (error)
return (error);
indiroff = (lbn - NDADDR) % NINDIR(fs);
blkno = ((ufs2_daddr_t *)(bp->b_data))[indiroff];
bqrelse(bp);
}
if (blkno != 0) {
if ((error = bread(snapvp, lbn, fs->fs_bsize, KERNCRED, &bp)))
return (error);
} else {
error = ffs_balloc_ufs2(snapvp, lblktosize(fs, (off_t)lbn),
fs->fs_bsize, KERNCRED, 0, &bp);
if (error)
return (error);
if ((error = readblock(snapvp, bp, lbn)) != 0)
return (error);
}
/*
* Set a snapshot inode to be a zero length file, regular files
* to be completely unallocated.
*/
dip = (struct ufs2_dinode *)bp->b_data +
ino_to_fsbo(fs, cancelip->i_number);
if (clearmode || cancelip->i_effnlink == 0)
dip->di_mode = 0;
dip->di_size = 0;
dip->di_blocks = 0;
dip->di_flags &= ~SF_SNAPSHOT;
bzero(&dip->di_db[0], (NDADDR + NIADDR) * sizeof(ufs2_daddr_t));
bdwrite(bp);
/*
* 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_din2->di_db[0],
&cancelip->i_din2->di_db[NDADDR], fs, 0, expungetype)))
return (error);
if ((error = (*acctfunc)(snapvp, &cancelip->i_din2->di_ib[0],
&cancelip->i_din2->di_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,
cancelip->i_din2->di_ib[i], 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(snapvp, cancelvp, level, blkno, lbn, rlbn, remblks,
blksperindir, fs, acctfunc, expungetype)
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, num, i;
ufs_lbn_t subblksperindir;
struct indir indirs[NIADDR + 2];
ufs2_daddr_t last, *bap;
struct buf *bp;
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, 0);
bp->b_blkno = fsbtodb(fs, blkno);
if ((bp->b_flags & (B_DONE | B_DELWRI)) == 0 &&
(error = readblock(cancelvp, bp, fragstoblks(fs, blkno)))) {
brelse(bp);
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, (caddr_t)bap, fs->fs_bsize);
bqrelse(bp);
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, 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_ufs2(vp, oldblkp, lastblkp, fs, lblkno, exptype)
struct vnode *vp;
ufs2_daddr_t *oldblkp, *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(vp, oldblkp, lastblkp, fs, lblkno, expungetype)
struct vnode *vp;
ufs2_daddr_t *oldblkp, *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;
for ( ; oldblkp < lastblkp; oldblkp++) {
blkno = *oldblkp;
if (blkno == 0 || blkno == BLK_NOCOPY || blkno == BLK_SNAP)
continue;
lbn = fragstoblks(fs, blkno);
if (lbn < NDADDR) {
blkp = &ip->i_din2->di_db[lbn];
ip->i_flag |= IN_CHANGE | IN_UPDATE;
} else {
error = ffs_balloc_ufs2(vp, lblktosize(fs, (off_t)lbn),
fs->fs_bsize, KERNCRED, BA_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.
*/
if (expungetype == BLK_SNAP && *blkp == BLK_NOCOPY) {
if (lbn >= NDADDR)
brelse(ibp);
} else {
if (*blkp != 0)
panic("snapacct_ufs2: bad block");
*blkp = expungetype;
if (lbn >= NDADDR)
bdwrite(ibp);
}
}
return (0);
}
/*
* Account for a set of blocks allocated in a snapshot inode.
*/
static int
mapacct_ufs2(vp, oldblkp, lastblkp, fs, lblkno, expungetype)
struct vnode *vp;
ufs2_daddr_t *oldblkp, *lastblkp;
struct fs *fs;
ufs_lbn_t lblkno;
int expungetype;
{
ufs2_daddr_t blkno;
struct inode *ip;
ino_t inum;
int acctit;
ip = VTOI(vp);
inum = ip->i_number;
if (lblkno == -1)
acctit = 0;
else
acctit = 1;
for ( ; oldblkp < lastblkp; oldblkp++, lblkno++) {
blkno = *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 = blkstofrags(fs, lblkno);
ffs_blkfree(ip->i_ump, fs, vp, blkno, fs->fs_bsize, inum,
vp->v_type, NULL);
}
return (0);
}
/*
* 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(ip)
struct inode *ip;
{
struct inode *xp;
struct fs *fs;
int snaploc;
struct snapdata *sn;
struct ufsmount *ump;
/*
* Find snapshot in incore list.
*/
xp = NULL;
sn = ip->i_devvp->v_rdev->si_snapdata;
if (sn != NULL)
TAILQ_FOREACH(xp, &sn->sn_head, i_nextsnap)
if (xp == ip)
break;
if (xp != NULL)
vrele(ITOV(ip));
else if (snapdebug)
printf("ffs_snapgone: lost snapshot vnode %ju\n",
(uintmax_t)ip->i_number);
/*
* Delete snapshot inode from superblock. Keep list dense.
*/
fs = ip->i_fs;
ump = ip->i_ump;
UFS_LOCK(ump);
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;
}
UFS_UNLOCK(ump);
}
/*
* Prepare a snapshot file for being removed.
*/
void
ffs_snapremove(vp)
struct vnode *vp;
{
struct inode *ip;
struct vnode *devvp;
struct buf *ibp;
struct fs *fs;
ufs2_daddr_t numblks, blkno, dblk;
int error, loc, last;
struct snapdata *sn;
ip = VTOI(vp);
fs = ip->i_fs;
devvp = ip->i_devvp;
/*
* 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.
*/
VI_LOCK(devvp);
if (ip->i_nextsnap.tqe_prev != 0) {
sn = devvp->v_rdev->si_snapdata;
TAILQ_REMOVE(&sn->sn_head, ip, i_nextsnap);
ip->i_nextsnap.tqe_prev = 0;
VI_UNLOCK(devvp);
lockmgr(&vp->v_lock, LK_EXCLUSIVE, NULL);
KASSERT(vp->v_vnlock == &sn->sn_lock,
("ffs_snapremove: lost lock mutation"));
vp->v_vnlock = &vp->v_lock;
VI_LOCK(devvp);
lockmgr(&sn->sn_lock, LK_RELEASE, NULL);
try_free_snapdata(devvp);
} else
VI_UNLOCK(devvp);
/*
* 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 = DIP(ip, i_db[blkno]);
if (dblk == 0)
continue;
if (dblk == BLK_NOCOPY || dblk == BLK_SNAP)
DIP_SET(ip, i_db[blkno], 0);
else if ((dblk == blkstofrags(fs, blkno) &&
ffs_snapblkfree(fs, ip->i_devvp, dblk, fs->fs_bsize,
ip->i_number, vp->v_type, NULL))) {
DIP_SET(ip, i_blocks, DIP(ip, i_blocks) -
btodb(fs->fs_bsize));
DIP_SET(ip, i_db[blkno], 0);
}
}
numblks = howmany(ip->i_size, fs->fs_bsize);
for (blkno = NDADDR; blkno < numblks; blkno += NINDIR(fs)) {
error = UFS_BALLOC(vp, lblktosize(fs, (off_t)blkno),
fs->fs_bsize, KERNCRED, BA_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++) {
if (ip->i_ump->um_fstype == UFS1) {
dblk = ((ufs1_daddr_t *)(ibp->b_data))[loc];
if (dblk == 0)
continue;
if (dblk == BLK_NOCOPY || dblk == BLK_SNAP)
((ufs1_daddr_t *)(ibp->b_data))[loc]= 0;
else if ((dblk == blkstofrags(fs, blkno) &&
ffs_snapblkfree(fs, ip->i_devvp, dblk,
fs->fs_bsize, ip->i_number, vp->v_type,
NULL))) {
ip->i_din1->di_blocks -=
btodb(fs->fs_bsize);
((ufs1_daddr_t *)(ibp->b_data))[loc]= 0;
}
continue;
}
dblk = ((ufs2_daddr_t *)(ibp->b_data))[loc];
if (dblk == 0)
continue;
if (dblk == BLK_NOCOPY || dblk == BLK_SNAP)
((ufs2_daddr_t *)(ibp->b_data))[loc] = 0;
else if ((dblk == blkstofrags(fs, blkno) &&
ffs_snapblkfree(fs, ip->i_devvp, dblk,
fs->fs_bsize, ip->i_number, vp->v_type, NULL))) {
ip->i_din2->di_blocks -= btodb(fs->fs_bsize);
((ufs2_daddr_t *)(ibp->b_data))[loc] = 0;
}
}
bawrite(ibp);
}
/*
* Clear snapshot flag and drop reference.
*/
ip->i_flags &= ~SF_SNAPSHOT;
DIP_SET(ip, i_flags, ip->i_flags);
ip->i_flag |= IN_CHANGE | IN_UPDATE;
/*
* The dirtied indirects must be written out before
* softdep_setup_freeblocks() is called. Otherwise indir_trunc()
* may find indirect pointers using the magic BLK_* values.
*/
if (DOINGSOFTDEP(vp))
ffs_syncvnode(vp, MNT_WAIT, 0);
#ifdef QUOTA
/*
* Reenable disk quotas for ex-snapshot file.
*/
if (!getinoquota(ip))
(void) chkdq(ip, DIP(ip, i_blocks), KERNCRED, 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(fs, devvp, bno, size, inum, vtype, wkhd)
struct fs *fs;
struct vnode *devvp;
ufs2_daddr_t bno;
long size;
ino_t inum;
enum vtype vtype;
struct workhead *wkhd;
{
struct buf *ibp, *cbp, *savedcbp = NULL;
struct thread *td = curthread;
struct inode *ip;
struct vnode *vp = NULL;
ufs_lbn_t lbn;
ufs2_daddr_t blkno;
int indiroff = 0, error = 0, claimedblk = 0;
struct snapdata *sn;
lbn = fragstoblks(fs, bno);
retry:
VI_LOCK(devvp);
sn = devvp->v_rdev->si_snapdata;
if (sn == NULL) {
VI_UNLOCK(devvp);
return (0);
}
if (lockmgr(&sn->sn_lock, LK_INTERLOCK | LK_EXCLUSIVE | LK_SLEEPFAIL,
VI_MTX(devvp)) != 0)
goto retry;
TAILQ_FOREACH(ip, &sn->sn_head, i_nextsnap) {
vp = ITOV(ip);
if (DOINGSOFTDEP(vp))
softdep_prealloc(vp, MNT_WAIT);
/*
* Lookup block being written.
*/
if (lbn < NDADDR) {
blkno = DIP(ip, i_db[lbn]);
} else {
td->td_pflags |= TDP_COWINPROGRESS;
error = UFS_BALLOC(vp, lblktosize(fs, (off_t)lbn),
fs->fs_bsize, KERNCRED, BA_METAONLY, &ibp);
td->td_pflags &= ~TDP_COWINPROGRESS;
if (error)
break;
indiroff = (lbn - NDADDR) % NINDIR(fs);
if (ip->i_ump->um_fstype == UFS1)
blkno=((ufs1_daddr_t *)(ibp->b_data))[indiroff];
else
blkno=((ufs2_daddr_t *)(ibp->b_data))[indiroff];
}
/*
* 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) {
DIP_SET(ip, i_db[lbn], BLK_NOCOPY);
ip->i_flag |= IN_CHANGE | IN_UPDATE;
} else if (ip->i_ump->um_fstype == UFS1) {
((ufs1_daddr_t *)(ibp->b_data))[indiroff] =
BLK_NOCOPY;
bdwrite(ibp);
} else {
((ufs2_daddr_t *)(ibp->b_data))[indiroff] =
BLK_NOCOPY;
bdwrite(ibp);
}
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)
bqrelse(ibp);
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 %ju lbn %jd from inum %ju\n",
"Grabonremove: snapino",
(uintmax_t)ip->i_number,
(intmax_t)lbn, (uintmax_t)inum);
#endif
/*
* If journaling is tracking this write we must add
* the work to the inode or indirect being written.
*/
if (wkhd != NULL) {
if (lbn < NDADDR)
softdep_inode_append(ip,
curthread->td_ucred, wkhd);
else
softdep_buf_append(ibp, wkhd);
}
if (lbn < NDADDR) {
DIP_SET(ip, i_db[lbn], bno);
} else if (ip->i_ump->um_fstype == UFS1) {
((ufs1_daddr_t *)(ibp->b_data))[indiroff] = bno;
bdwrite(ibp);
} else {
((ufs2_daddr_t *)(ibp->b_data))[indiroff] = bno;
bdwrite(ibp);
}
DIP_SET(ip, i_blocks, DIP(ip, i_blocks) + btodb(size));
ip->i_flag |= IN_CHANGE | IN_UPDATE;
lockmgr(vp->v_vnlock, LK_RELEASE, NULL);
return (1);
}
if (lbn >= NDADDR)
bqrelse(ibp);
/*
* Allocate the block into which to do the copy. Note that this
* allocation will never require any additional allocations for
* the snapshot inode.
*/
td->td_pflags |= TDP_COWINPROGRESS;
error = UFS_BALLOC(vp, lblktosize(fs, (off_t)lbn),
fs->fs_bsize, KERNCRED, 0, &cbp);
td->td_pflags &= ~TDP_COWINPROGRESS;
if (error)
break;
#ifdef DEBUG
if (snapdebug)
printf("%s%ju lbn %jd %s %ju size %ld to blkno %jd\n",
"Copyonremove: snapino ", (uintmax_t)ip->i_number,
(intmax_t)lbn, "for inum", (uintmax_t)inum, size,
(intmax_t)cbp->b_blkno);
#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. At a minimum we ensure the
* integrity of the filesystem metadata, but use the
* dopersistence sysctl-setable flag to decide on the
* persistence needed for file content data.
*/
if (savedcbp != 0) {
bcopy(savedcbp->b_data, cbp->b_data, fs->fs_bsize);
bawrite(cbp);
if ((vtype == VDIR || dopersistence) &&
ip->i_effnlink > 0)
(void) ffs_syncvnode(vp, MNT_WAIT, NO_INO_UPDT);
continue;
}
/*
* Otherwise, read the old block contents into the buffer.
*/
if ((error = readblock(vp, cbp, lbn)) != 0) {
bzero(cbp->b_data, fs->fs_bsize);
bawrite(cbp);
if ((vtype == VDIR || dopersistence) &&
ip->i_effnlink > 0)
(void) ffs_syncvnode(vp, MNT_WAIT, NO_INO_UPDT);
break;
}
savedcbp = cbp;
}
/*
* 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. At a minimum we
* ensure the integrity of the filesystem metadata, but
* use the dopersistence sysctl-setable flag to decide on
* the persistence needed for file content data.
*/
if (savedcbp) {
vp = savedcbp->b_vp;
bawrite(savedcbp);
if ((vtype == VDIR || dopersistence) &&
VTOI(vp)->i_effnlink > 0)
(void) ffs_syncvnode(vp, MNT_WAIT, NO_INO_UPDT);
}
/*
* 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 (error != 0 && wkhd != NULL)
softdep_freework(wkhd);
lockmgr(vp->v_vnlock, LK_RELEASE, NULL);
return (error);
}
/*
* Associate snapshot files when mounting.
*/
void
ffs_snapshot_mount(mp)
struct mount *mp;
{
struct ufsmount *ump = VFSTOUFS(mp);
struct vnode *devvp = ump->um_devvp;
struct fs *fs = ump->um_fs;
struct thread *td = curthread;
struct snapdata *sn;
struct vnode *vp;
struct vnode *lastvp;
struct inode *ip;
struct uio auio;
struct iovec aiov;
void *snapblklist;
char *reason;
daddr_t snaplistsize;
int error, snaploc, loc;
/*
* 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;
lastvp = NULL;
sn = NULL;
for (snaploc = 0; snaploc < FSMAXSNAP; snaploc++) {
if (fs->fs_snapinum[snaploc] == 0)
break;
if ((error = ffs_vget(mp, fs->fs_snapinum[snaploc],
LK_EXCLUSIVE, &vp)) != 0){
printf("ffs_snapshot_mount: vget failed %d\n", error);
continue;
}
ip = VTOI(vp);
if (!IS_SNAPSHOT(ip) || ip->i_size ==
lblktosize(fs, howmany(fs->fs_size, fs->fs_frag))) {
if (!IS_SNAPSHOT(ip)) {
reason = "non-snapshot";
} else {
reason = "old format snapshot";
(void)ffs_truncate(vp, (off_t)0, 0, NOCRED);
(void)ffs_syncvnode(vp, MNT_WAIT, 0);
}
printf("ffs_snapshot_mount: %s inode %d\n",
reason, 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;
}
/*
* Acquire a lock on the snapdata structure, creating it if
* necessary.
*/
sn = ffs_snapdata_acquire(devvp);
/*
* Change vnode to use shared snapshot lock instead of the
* original private lock.
*/
vp->v_vnlock = &sn->sn_lock;
lockmgr(&vp->v_lock, LK_RELEASE, NULL);
/*
* Link it onto the active snapshot list.
*/
VI_LOCK(devvp);
if (ip->i_nextsnap.tqe_prev != 0)
panic("ffs_snapshot_mount: %ju already on list",
(uintmax_t)ip->i_number);
else
TAILQ_INSERT_TAIL(&sn->sn_head, ip, i_nextsnap);
vp->v_vflag |= VV_SYSTEM;
VI_UNLOCK(devvp);
VOP_UNLOCK(vp, 0);
lastvp = vp;
}
vp = lastvp;
/*
* No usable snapshots found.
*/
if (sn == NULL || vp == NULL)
return;
/*
* Allocate the space for the block hints list. We always want to
* use the list from the newest snapshot.
*/
auio.uio_iov = &aiov;
auio.uio_iovcnt = 1;
aiov.iov_base = (void *)&snaplistsize;
aiov.iov_len = sizeof(snaplistsize);
auio.uio_resid = aiov.iov_len;
auio.uio_offset =
lblktosize(fs, howmany(fs->fs_size, fs->fs_frag));
auio.uio_segflg = UIO_SYSSPACE;
auio.uio_rw = UIO_READ;
auio.uio_td = td;
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
if ((error = VOP_READ(vp, &auio, IO_UNIT, td->td_ucred)) != 0) {
printf("ffs_snapshot_mount: read_1 failed %d\n", error);
VOP_UNLOCK(vp, 0);
return;
}
snapblklist = malloc(snaplistsize * sizeof(daddr_t),
M_UFSMNT, M_WAITOK);
auio.uio_iovcnt = 1;
aiov.iov_base = snapblklist;
aiov.iov_len = snaplistsize * sizeof (daddr_t);
auio.uio_resid = aiov.iov_len;
auio.uio_offset -= sizeof(snaplistsize);
if ((error = VOP_READ(vp, &auio, IO_UNIT, td->td_ucred)) != 0) {
printf("ffs_snapshot_mount: read_2 failed %d\n", error);
VOP_UNLOCK(vp, 0);
free(snapblklist, M_UFSMNT);
return;
}
VOP_UNLOCK(vp, 0);
VI_LOCK(devvp);
ASSERT_VOP_LOCKED(devvp, "ffs_snapshot_mount");
sn->sn_listsize = snaplistsize;
sn->sn_blklist = (daddr_t *)snapblklist;
devvp->v_vflag |= VV_COPYONWRITE;
VI_UNLOCK(devvp);
}
/*
* Disassociate snapshot files when unmounting.
*/
void
ffs_snapshot_unmount(mp)
struct mount *mp;
{
struct vnode *devvp = VFSTOUFS(mp)->um_devvp;
struct snapdata *sn;
struct inode *xp;
struct vnode *vp;
VI_LOCK(devvp);
sn = devvp->v_rdev->si_snapdata;
while (sn != NULL && (xp = TAILQ_FIRST(&sn->sn_head)) != NULL) {
vp = ITOV(xp);
TAILQ_REMOVE(&sn->sn_head, xp, i_nextsnap);
xp->i_nextsnap.tqe_prev = 0;
lockmgr(&sn->sn_lock, LK_INTERLOCK | LK_EXCLUSIVE,
VI_MTX(devvp));
lockmgr(&vp->v_lock, LK_EXCLUSIVE, NULL);
KASSERT(vp->v_vnlock == &sn->sn_lock,
("ffs_snapshot_unmount: lost lock mutation"));
vp->v_vnlock = &vp->v_lock;
lockmgr(&vp->v_lock, LK_RELEASE, NULL);
lockmgr(&sn->sn_lock, LK_RELEASE, NULL);
if (xp->i_effnlink > 0)
vrele(vp);
VI_LOCK(devvp);
sn = devvp->v_rdev->si_snapdata;
}
try_free_snapdata(devvp);
ASSERT_VOP_LOCKED(devvp, "ffs_snapshot_unmount");
}
/*
* Check the buffer block to be belong to device buffer that shall be
* locked after snaplk. devvp shall be locked on entry, and will be
* leaved locked upon exit.
*/
static int
ffs_bp_snapblk(devvp, bp)
struct vnode *devvp;
struct buf *bp;
{
struct snapdata *sn;
struct fs *fs;
ufs2_daddr_t lbn, *snapblklist;
int lower, upper, mid;
ASSERT_VI_LOCKED(devvp, "ffs_bp_snapblk");
KASSERT(devvp->v_type == VCHR, ("Not a device %p", devvp));
sn = devvp->v_rdev->si_snapdata;
if (sn == NULL || TAILQ_FIRST(&sn->sn_head) == NULL)
return (0);
fs = TAILQ_FIRST(&sn->sn_head)->i_fs;
lbn = fragstoblks(fs, dbtofsb(fs, bp->b_blkno));
snapblklist = sn->sn_blklist;
upper = sn->sn_listsize - 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)
return (1);
return (0);
}
void
ffs_bdflush(bo, bp)
struct bufobj *bo;
struct buf *bp;
{
struct thread *td;
struct vnode *vp, *devvp;
struct buf *nbp;
int bp_bdskip;
if (bo->bo_dirty.bv_cnt <= dirtybufthresh)
return;
td = curthread;
vp = bp->b_vp;
devvp = bo->__bo_vnode;
KASSERT(vp == devvp, ("devvp != vp %p %p", bo, bp));
VI_LOCK(devvp);
bp_bdskip = ffs_bp_snapblk(devvp, bp);
if (bp_bdskip)
bdwriteskip++;
VI_UNLOCK(devvp);
if (bo->bo_dirty.bv_cnt > dirtybufthresh + 10 && !bp_bdskip) {
(void) VOP_FSYNC(vp, MNT_NOWAIT, td);
altbufferflushes++;
} else {
BO_LOCK(bo);
/*
* Try to find a buffer to flush.
*/
TAILQ_FOREACH(nbp, &bo->bo_dirty.bv_hd, b_bobufs) {
if ((nbp->b_vflags & BV_BKGRDINPROG) ||
BUF_LOCK(nbp,
LK_EXCLUSIVE | LK_NOWAIT, NULL))
continue;
if (bp == nbp)
panic("bdwrite: found ourselves");
BO_UNLOCK(bo);
/*
* Don't countdeps with the bo lock
* held.
*/
if (buf_countdeps(nbp, 0)) {
BO_LOCK(bo);
BUF_UNLOCK(nbp);
continue;
}
if (bp_bdskip) {
VI_LOCK(devvp);
if (!ffs_bp_snapblk(vp, nbp)) {
if (BO_MTX(bo) != VI_MTX(vp)) {
VI_UNLOCK(devvp);
BO_LOCK(bo);
}
BUF_UNLOCK(nbp);
continue;
}
VI_UNLOCK(devvp);
}
if (nbp->b_flags & B_CLUSTEROK) {
vfs_bio_awrite(nbp);
} else {
bremfree(nbp);
bawrite(nbp);
}
dirtybufferflushes++;
break;
}
if (nbp == NULL)
BO_UNLOCK(bo);
}
}
/*
* Check for need to copy block that is about to be written,
* copying the block if necessary.
*/
int
ffs_copyonwrite(devvp, bp)
struct vnode *devvp;
struct buf *bp;
{
struct snapdata *sn;
struct buf *ibp, *cbp, *savedcbp = NULL;
struct thread *td = curthread;
struct fs *fs;
struct inode *ip;
struct vnode *vp = NULL;
ufs2_daddr_t lbn, blkno, *snapblklist;
int lower, upper, mid, indiroff, error = 0;
int launched_async_io, prev_norunningbuf;
long saved_runningbufspace;
if (devvp != bp->b_vp && IS_SNAPSHOT(VTOI(bp->b_vp)))
return (0); /* Update on a snapshot file */
if (td->td_pflags & TDP_COWINPROGRESS)
panic("ffs_copyonwrite: recursive call");
/*
* First check to see if it is in the preallocated list.
* By doing this check we avoid several potential deadlocks.
*/
VI_LOCK(devvp);
sn = devvp->v_rdev->si_snapdata;
if (sn == NULL ||
TAILQ_EMPTY(&sn->sn_head)) {
VI_UNLOCK(devvp);
return (0); /* No snapshot */
}
ip = TAILQ_FIRST(&sn->sn_head);
fs = ip->i_fs;
lbn = fragstoblks(fs, dbtofsb(fs, bp->b_blkno));
snapblklist = sn->sn_blklist;
upper = sn->sn_listsize - 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) {
VI_UNLOCK(devvp);
return (0);
}
launched_async_io = 0;
prev_norunningbuf = td->td_pflags & TDP_NORUNNINGBUF;
/*
* Since I/O on bp isn't yet in progress and it may be blocked
* for a long time waiting on snaplk, back it out of
* runningbufspace, possibly waking other threads waiting for space.
*/
saved_runningbufspace = bp->b_runningbufspace;
if (saved_runningbufspace != 0)
runningbufwakeup(bp);
/*
* Not in the precomputed list, so check the snapshots.
*/
while (lockmgr(&sn->sn_lock, LK_INTERLOCK | LK_EXCLUSIVE | LK_SLEEPFAIL,
VI_MTX(devvp)) != 0) {
VI_LOCK(devvp);
sn = devvp->v_rdev->si_snapdata;
if (sn == NULL ||
TAILQ_EMPTY(&sn->sn_head)) {
VI_UNLOCK(devvp);
if (saved_runningbufspace != 0) {
bp->b_runningbufspace = saved_runningbufspace;
atomic_add_long(&runningbufspace,
bp->b_runningbufspace);
}
return (0); /* Snapshot gone */
}
}
TAILQ_FOREACH(ip, &sn->sn_head, i_nextsnap) {
vp = ITOV(ip);
if (DOINGSOFTDEP(vp))
softdep_prealloc(vp, MNT_WAIT);
/*
* 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 UFS_BALLOC.
*/
if (bp->b_vp == vp)
continue;
/*
* 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 = DIP(ip, i_db[lbn]);
} else {
td->td_pflags |= TDP_COWINPROGRESS | TDP_NORUNNINGBUF;
error = UFS_BALLOC(vp, lblktosize(fs, (off_t)lbn),
fs->fs_bsize, KERNCRED, BA_METAONLY, &ibp);
td->td_pflags &= ~TDP_COWINPROGRESS;
if (error)
break;
indiroff = (lbn - NDADDR) % NINDIR(fs);
if (ip->i_ump->um_fstype == UFS1)
blkno=((ufs1_daddr_t *)(ibp->b_data))[indiroff];
else
blkno=((ufs2_daddr_t *)(ibp->b_data))[indiroff];
bqrelse(ibp);
}
#ifdef INVARIANTS
if (blkno == BLK_SNAP && bp->b_lblkno >= 0)
panic("ffs_copyonwrite: bad copy block");
#endif
if (blkno != 0)
continue;
/*
* 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.
*/
td->td_pflags |= TDP_COWINPROGRESS | TDP_NORUNNINGBUF;
error = UFS_BALLOC(vp, lblktosize(fs, (off_t)lbn),
fs->fs_bsize, KERNCRED, 0, &cbp);
td->td_pflags &= ~TDP_COWINPROGRESS;
if (error)
break;
#ifdef DEBUG
if (snapdebug) {
printf("Copyonwrite: snapino %ju lbn %jd for ",
(uintmax_t)ip->i_number, (intmax_t)lbn);
if (bp->b_vp == devvp)
printf("fs metadata");
else
printf("inum %ju",
(uintmax_t)VTOI(bp->b_vp)->i_number);
printf(" lblkno %jd to blkno %jd\n",
(intmax_t)bp->b_lblkno, (intmax_t)cbp->b_blkno);
}
#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. At a minimum we ensure the
* integrity of the filesystem metadata, but use the
* dopersistence sysctl-setable flag to decide on the
* persistence needed for file content data.
*/
if (savedcbp != 0) {
bcopy(savedcbp->b_data, cbp->b_data, fs->fs_bsize);
bawrite(cbp);
if ((devvp == bp->b_vp || bp->b_vp->v_type == VDIR ||
dopersistence) && ip->i_effnlink > 0)
(void) ffs_syncvnode(vp, MNT_WAIT, NO_INO_UPDT);
else
launched_async_io = 1;
continue;
}
/*
* Otherwise, read the old block contents into the buffer.
*/
if ((error = readblock(vp, cbp, lbn)) != 0) {
bzero(cbp->b_data, fs->fs_bsize);
bawrite(cbp);
if ((devvp == bp->b_vp || bp->b_vp->v_type == VDIR ||
dopersistence) && ip->i_effnlink > 0)
(void) ffs_syncvnode(vp, MNT_WAIT, NO_INO_UPDT);
else
launched_async_io = 1;
break;
}
savedcbp = cbp;
}
/*
* 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. At a minimum we
* ensure the integrity of the filesystem metadata, but
* use the dopersistence sysctl-setable flag to decide on
* the persistence needed for file content data.
*/
if (savedcbp) {
vp = savedcbp->b_vp;
bawrite(savedcbp);
if ((devvp == bp->b_vp || bp->b_vp->v_type == VDIR ||
dopersistence) && VTOI(vp)->i_effnlink > 0)
(void) ffs_syncvnode(vp, MNT_WAIT, NO_INO_UPDT);
else
launched_async_io = 1;
}
lockmgr(vp->v_vnlock, LK_RELEASE, NULL);
td->td_pflags = (td->td_pflags & ~TDP_NORUNNINGBUF) |
prev_norunningbuf;
if (launched_async_io && (td->td_pflags & TDP_NORUNNINGBUF) == 0)
waitrunningbufspace();
/*
* I/O on bp will now be started, so count it in runningbufspace.
*/
if (saved_runningbufspace != 0) {
bp->b_runningbufspace = saved_runningbufspace;
atomic_add_long(&runningbufspace, bp->b_runningbufspace);
}
return (error);
}
/*
* sync snapshots to force freework records waiting on snapshots to claim
* blocks to free.
*/
void
ffs_sync_snap(mp, waitfor)
struct mount *mp;
int waitfor;
{
struct snapdata *sn;
struct vnode *devvp;
struct vnode *vp;
struct inode *ip;
devvp = VFSTOUFS(mp)->um_devvp;
if ((devvp->v_vflag & VV_COPYONWRITE) == 0)
return;
for (;;) {
VI_LOCK(devvp);
sn = devvp->v_rdev->si_snapdata;
if (sn == NULL) {
VI_UNLOCK(devvp);
return;
}
if (lockmgr(&sn->sn_lock,
LK_INTERLOCK | LK_EXCLUSIVE | LK_SLEEPFAIL,
VI_MTX(devvp)) == 0)
break;
}
TAILQ_FOREACH(ip, &sn->sn_head, i_nextsnap) {
vp = ITOV(ip);
ffs_syncvnode(vp, waitfor, NO_INO_UPDT);
}
lockmgr(&sn->sn_lock, LK_RELEASE, NULL);
}
/*
* Read the specified block into the given buffer.
* Much of this boiler-plate comes from bwrite().
*/
static int
readblock(vp, bp, lbn)
struct vnode *vp;
struct buf *bp;
ufs2_daddr_t lbn;
{
struct inode *ip = VTOI(vp);
struct bio *bip;
bip = g_alloc_bio();
bip->bio_cmd = BIO_READ;
bip->bio_offset = dbtob(fsbtodb(ip->i_fs, blkstofrags(ip->i_fs, lbn)));
bip->bio_data = bp->b_data;
bip->bio_length = bp->b_bcount;
bip->bio_done = NULL;
g_io_request(bip, ip->i_devvp->v_bufobj.bo_private);
bp->b_error = biowait(bip, "snaprdb");
g_destroy_bio(bip);
return (bp->b_error);
}
#endif
/*
* Process file deletes that were deferred by ufs_inactive() due to
* the file system being suspended. Transfer IN_LAZYACCESS into
* IN_MODIFIED for vnodes that were accessed during suspension.
*/
void
process_deferred_inactive(struct mount *mp)
{
struct vnode *vp, *mvp;
struct inode *ip;
struct thread *td;
int error;
td = curthread;
(void) vn_start_secondary_write(NULL, &mp, V_WAIT);
loop:
MNT_VNODE_FOREACH_ALL(vp, mp, mvp) {
/*
* IN_LAZYACCESS is checked here without holding any
* vnode lock, but this flag is set only while holding
* vnode interlock.
*/
if (vp->v_type == VNON ||
((VTOI(vp)->i_flag & IN_LAZYACCESS) == 0 &&
((vp->v_iflag & VI_OWEINACT) == 0 || vp->v_usecount > 0))) {
VI_UNLOCK(vp);
continue;
}
vholdl(vp);
error = vn_lock(vp, LK_EXCLUSIVE | LK_INTERLOCK);
if (error != 0) {
vdrop(vp);
if (error == ENOENT)
continue; /* vnode recycled */
MNT_VNODE_FOREACH_ALL_ABORT(mp, mvp);
goto loop;
}
ip = VTOI(vp);
if ((ip->i_flag & IN_LAZYACCESS) != 0) {
ip->i_flag &= ~IN_LAZYACCESS;
ip->i_flag |= IN_MODIFIED;
}
VI_LOCK(vp);
if ((vp->v_iflag & VI_OWEINACT) == 0 || vp->v_usecount > 0) {
VI_UNLOCK(vp);
VOP_UNLOCK(vp, 0);
vdrop(vp);
continue;
}
vinactive(vp, td);
VNASSERT((vp->v_iflag & VI_OWEINACT) == 0, vp,
("process_deferred_inactive: got VI_OWEINACT"));
VI_UNLOCK(vp);
VOP_UNLOCK(vp, 0);
vdrop(vp);
}
vn_finished_secondary_write(mp);
}
#ifndef NO_FFS_SNAPSHOT
static struct snapdata *
ffs_snapdata_alloc(void)
{
struct snapdata *sn;
/*
* Fetch a snapdata from the free list if there is one available.
*/
mtx_lock(&snapfree_lock);
sn = LIST_FIRST(&snapfree);
if (sn != NULL)
LIST_REMOVE(sn, sn_link);
mtx_unlock(&snapfree_lock);
if (sn != NULL)
return (sn);
/*
* If there were no free snapdatas allocate one.
*/
sn = malloc(sizeof *sn, M_UFSMNT, M_WAITOK | M_ZERO);
TAILQ_INIT(&sn->sn_head);
lockinit(&sn->sn_lock, PVFS, "snaplk", VLKTIMEOUT,
LK_CANRECURSE | LK_NOSHARE);
return (sn);
}
/*
* The snapdata is never freed because we can not be certain that
* there are no threads sleeping on the snap lock. Persisting
* them permanently avoids costly synchronization in ffs_lock().
*/
static void
ffs_snapdata_free(struct snapdata *sn)
{
mtx_lock(&snapfree_lock);
LIST_INSERT_HEAD(&snapfree, sn, sn_link);
mtx_unlock(&snapfree_lock);
}
/* Try to free snapdata associated with devvp */
static void
try_free_snapdata(struct vnode *devvp)
{
struct snapdata *sn;
ufs2_daddr_t *snapblklist;
ASSERT_VI_LOCKED(devvp, "try_free_snapdata");
sn = devvp->v_rdev->si_snapdata;
if (sn == NULL || TAILQ_FIRST(&sn->sn_head) != NULL ||
(devvp->v_vflag & VV_COPYONWRITE) == 0) {
VI_UNLOCK(devvp);
return;
}
devvp->v_rdev->si_snapdata = NULL;
devvp->v_vflag &= ~VV_COPYONWRITE;
lockmgr(&sn->sn_lock, LK_DRAIN|LK_INTERLOCK, VI_MTX(devvp));
snapblklist = sn->sn_blklist;
sn->sn_blklist = NULL;
sn->sn_listsize = 0;
lockmgr(&sn->sn_lock, LK_RELEASE, NULL);
if (snapblklist != NULL)
free(snapblklist, M_UFSMNT);
ffs_snapdata_free(sn);
}
static struct snapdata *
ffs_snapdata_acquire(struct vnode *devvp)
{
struct snapdata *nsn;
struct snapdata *sn;
/*
* Allocate a free snapdata. This is done before acquiring the
* devvp lock to avoid allocation while the devvp interlock is
* held.
*/
nsn = ffs_snapdata_alloc();
/*
* If there snapshots already exist on this filesystem grab a
* reference to the shared lock. Otherwise this is the first
* snapshot on this filesystem and we need to use our
* pre-allocated snapdata.
*/
VI_LOCK(devvp);
if (devvp->v_rdev->si_snapdata == NULL) {
devvp->v_rdev->si_snapdata = nsn;
nsn = NULL;
}
sn = devvp->v_rdev->si_snapdata;
/*
* Acquire the snapshot lock.
*/
lockmgr(&sn->sn_lock,
LK_INTERLOCK | LK_EXCLUSIVE | LK_RETRY, VI_MTX(devvp));
/*
* Free any unused snapdata.
*/
if (nsn != NULL)
ffs_snapdata_free(nsn);
return (sn);
}
#endif
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