tvbackup: add -i flag to avoid score prefetching (David Swasey) - plan9port - [fork] Plan 9 from user space
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---
(DIR) commit a4b5da0be757518006f2961838194905459548ef
(DIR) parent 89d6e06cb18a2c981586e63dba153656d8f1e92f
(HTM) Author: Russ Cox <rsc@swtch.com>
Date: Tue, 27 Nov 2007 15:49:09 -0500
vbackup: add -i flag to avoid score prefetching (David Swasey)
Diffstat:
M man/man8/vbackup.8 | 6 +++++-
M src/cmd/vbackup/vbackup.c | 101 +++++++++++++++++++------------
2 files changed, 68 insertions(+), 39 deletions(-)
---
(DIR) diff --git a/man/man8/vbackup.8 b/man/man8/vbackup.8
t@@ -5,7 +5,7 @@ back up Unix file systems to Venti
.SH SYNOPSIS
.B vbackup
[
-.B -DVnv
+.B -DVinv
]
[
.B -M
t@@ -154,6 +154,10 @@ The default is the name returned by
.B -n
No-op mode: do not write any blocks to the server
.TP
+.B -i
+Read scores incrementally from the previous backup as needed,
+rather than prefetching them.
+.TP
.B -v
Print verbose output.
.TP
(DIR) diff --git a/src/cmd/vbackup/vbackup.c b/src/cmd/vbackup/vbackup.c
t@@ -6,6 +6,7 @@
*
* -D print debugging
* -f 'fast' writes - skip write if block exists on server
+ * -i read old scores incrementally
* -m set mount name
* -M set mount place
* -n nop -- don't actually write blocks
t@@ -63,6 +64,7 @@ int errors; /* are we exiting with an error status? */
int fastwrites; /* do not write blocks already on server */
int fsscanblock; /* last block scanned */
Fsys* fsys; /* file system being backed up */
+int incremental; /* use vscores rather than bscores */
int nchange; /* number of changed blocks */
int nop; /* don't actually send blocks to venti */
int nskip; /* number of blocks skipped (already on server) */
t@@ -72,6 +74,7 @@ Queue* qventi; /* queue cmp->venti */
int statustime; /* print status every _ seconds */
int verbose; /* print extra stuff */
VtFile* vfile; /* venti file being written */
+VtFile* vscores; /* venti file with block scores */
Channel* writechan; /* chan(WriteReq) */
VtConn* z; /* connection to venti */
VtCache* zcache; /* cache of venti blocks */
t@@ -127,6 +130,9 @@ threadmain(int argc, char **argv)
case 'f':
fastwrites = 1;
break;
+ case 'i':
+ incremental = 1;
+ break;
case 'm':
mountname = EARGF(usage());
break;
t@@ -233,41 +239,49 @@ threadmain(int argc, char **argv)
sysfatal("file system block counts don't match %lld %lld", e.size, fsys->nblock*bsize);
}
- /*
- * write scores of blocks into temporary file
- */
- if((tmp = getenv("TMP")) != nil){
- /* okay, good */
- }else if(access("/var/tmp", 0) >= 0)
- tmp = "/var/tmp";
- else
- tmp = "/tmp";
- tmpnam = smprint("%s/vbackup.XXXXXX", tmp);
- if(tmpnam == nil)
- sysfatal("smprint: %r");
-
- if((fd = opentemp(tmpnam)) < 0)
- sysfatal("opentemp %s: %r", tmpnam);
- if(statustime)
- print("# %T reading scores into %s\n", tmpnam);
- if(verbose)
- fprint(2, "read scores into %s...\n", tmpnam);
-
- Binit(&bscores, fd, OWRITE);
- for(i=0; i<fsys->nblock; i++){
- if(vtfileblockscore(vfile, i, score) < 0)
- sysfatal("vtfileblockhash %d: %r", i);
- if(Bwrite(&bscores, score, VtScoreSize) != VtScoreSize)
- sysfatal("Bwrite: %r");
+ if(incremental){
+ if(vtfilegetentry(vfile, &e) < 0)
+ sysfatal("vtfilegetentry: %r");
+ if((vscores = vtfileopenroot(c, &e)) == nil)
+ sysfatal("vtfileopenroot: %r");
+ vtfileunlock(vfile);
+ }else{
+ /*
+ * write scores of blocks into temporary file
+ */
+ if((tmp = getenv("TMP")) != nil){
+ /* okay, good */
+ }else if(access("/var/tmp", 0) >= 0)
+ tmp = "/var/tmp";
+ else
+ tmp = "/tmp";
+ tmpnam = smprint("%s/vbackup.XXXXXX", tmp);
+ if(tmpnam == nil)
+ sysfatal("smprint: %r");
+
+ if((fd = opentemp(tmpnam)) < 0)
+ sysfatal("opentemp %s: %r", tmpnam);
+ if(statustime)
+ print("# %T reading scores into %s\n", tmpnam);
+ if(verbose)
+ fprint(2, "read scores into %s...\n", tmpnam);
+
+ Binit(&bscores, fd, OWRITE);
+ for(i=0; i<fsys->nblock; i++){
+ if(vtfileblockscore(vfile, i, score) < 0)
+ sysfatal("vtfileblockhash %d: %r", i);
+ if(Bwrite(&bscores, score, VtScoreSize) != VtScoreSize)
+ sysfatal("Bwrite: %r");
+ }
+ Bterm(&bscores);
+ vtfileunlock(vfile);
+
+ /*
+ * prep scores for rereading
+ */
+ seek(fd, 0, 0);
+ Binit(&bscores, fd, OREAD);
}
- Bterm(&bscores);
- vtfileunlock(vfile);
-
- /*
- * prep scores for rereading
- */
- seek(fd, 0, 0);
- Binit(&bscores, fd, OREAD);
/*
* start the main processes
t@@ -305,6 +319,8 @@ threadmain(int argc, char **argv)
/*
* prepare root block
*/
+ if(incremental)
+ vtfileclose(vscores);
vtfilelock(vfile, -1);
if(vtfileflush(vfile) < 0)
sysfatal("vtfileflush: %r");
t@@ -408,14 +424,21 @@ cmpproc(void *dummy)
USED(dummy);
+ if(incremental)
+ vtfilelock(vscores, VtOREAD);
bsize = fsys->blocksize;
while((db = qread(qcmp, &bno)) != nil){
data = db->data;
sha1(data, vtzerotruncate(VtDataType, data, bsize), score, nil);
- if(Bseek(&bscores, (vlong)bno*VtScoreSize, 0) < 0)
- sysfatal("cmpproc Bseek: %r");
- if(Bread(&bscores, score1, VtScoreSize) != VtScoreSize)
- sysfatal("cmpproc Bread: %r");
+ if(incremental){
+ if(vtfileblockscore(vscores, bno, score1) < 0)
+ sysfatal("cmpproc vtfileblockscore %d: %r", bno);
+ }else{
+ if(Bseek(&bscores, (vlong)bno*VtScoreSize, 0) < 0)
+ sysfatal("cmpproc Bseek: %r");
+ if(Bread(&bscores, score1, VtScoreSize) != VtScoreSize)
+ sysfatal("cmpproc Bread: %r");
+ }
if(memcmp(score, score1, VtScoreSize) != 0){
nchange++;
if(verbose)
t@@ -425,6 +448,8 @@ cmpproc(void *dummy)
blockput(db);
}
qclose(qventi);
+ if(incremental)
+ vtfileunlock(vscores);
if(statustime)
print("# %T cmp proc exiting\n");
runlock(&endlk);