Skip to content

HTTPS clone URL

Subversion checkout URL

You can clone with HTTPS or Subversion.

Download ZIP
Fetching contributors…

Cannot retrieve contributors at this time

471 lines (438 sloc) 14.123 kb
/*
* Copyright (c) 2004,2005 The DragonFly Project. All rights reserved.
*
* This code is derived from software contributed to The DragonFly Project
* by Matthew Dillon <dillon@backplane.com>
*
* 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.
* 3. Neither the name of The DragonFly Project nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific, prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* ``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 THE
* COPYRIGHT HOLDERS OR CONTRIBUTORS 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.
*
* $DragonFly: src/sbin/jscan/jstream.c,v 1.8 2005/09/07 07:20:23 dillon Exp $
*/
#include "jscan.h"
static struct jhash *JHashAry[JHASH_SIZE];
static void jnormalize(struct jstream *js);
static int jaddrecord_backtrack(struct jsession *ss, struct jdata *jd);
/*
* Integrate a raw record. Deal with the transaction begin and end flags
* to create a forward-referenced collection of jstream records. If we are
* able to complete a transaction, the first js associated with that
* transaction is returned.
*
* XXX we need to store the data for very large multi-record transactions
* separately since it might not fit into memory.
*
* Note that a transaction might represent a huge I/O operation, resulting
* in an overall node structure that spans gigabytes, but individual
* subrecord leaf nodes are limited in size and we depend on this to simplify
* the handling of leaf records.
*
* A transaction may cover several raw records. The jstream collection for
* a transaction is only returned when the entire transaction has been
* successfully scanned. Due to the interleaving of transactions the ordering
* of returned JS's may be different (not exactly reversed) when scanning a
* journal backwards verses forwards. Since parallel operations are
* theoretically non-conflicting, this should not present a problem.
*/
struct jstream *
jaddrecord(struct jsession *ss, struct jdata *jd)
{
struct journal_rawrecbeg *head;
struct jstream *js;
struct jhash *jh;
struct jhash **jhp;
js = malloc(sizeof(struct jstream));
bzero(js, sizeof(struct jstream));
js->js_jdata = jref(jd);
js->js_head = (void *)jd->jd_data;
js->js_session = ss;
head = js->js_head;
/*
* Check for a completely self-contained transaction, just return the
* js if possible.
*/
if ((head->streamid & (JREC_STREAMCTL_BEGIN|JREC_STREAMCTL_END)) ==
(JREC_STREAMCTL_BEGIN|JREC_STREAMCTL_END)
) {
jnormalize(js);
return (js);
}
retry:
/*
* Check for an open transaction in the hash table.
*/
jhp = &JHashAry[head->streamid & JHASH_MASK];
while ((jh = *jhp) != NULL) {
if (jh->jh_session == ss &&
((jh->jh_transid ^ head->streamid) & JREC_STREAMID_MASK) == 0
) {
break;
}
jhp = &jh->jh_hash;
}
/*
* We might have picked up a transaction in the middle, which we
* detect by not finding a hash record coupled with a raw record
* whos JREC_STREAMCTL_BEGIN bit is not set (or JREC_STREAMCTL_END
* bit if we are scanning backwards).
*
* When this case occurs we have to backtrack to locate the
* BEGIN (END if scanning backwards) and collect those records
* in order to obtain a complete transaction.
*
* This case most often occurs when a batch operation runs in
* prefix set whos starting raw-record transaction id is in
* the middle of one or more meta-transactions. It's a bit of
* a tricky situation, but easily resolvable by scanning the
* prefix set backwards (forwards if originally scanning backwards)
* to locate the raw record representing the start (end) of the
* transaction.
*/
if (jh == NULL) {
if (ss->ss_direction == JD_FORWARDS &&
(head->streamid & JREC_STREAMCTL_BEGIN) == 0
) {
if (verbose_opt > 1)
fprintf(stderr, "mid-transaction detected transid %016jx "
"streamid %04x\n",
(uintmax_t)jd->jd_transid,
head->streamid & JREC_STREAMID_MASK);
if (jaddrecord_backtrack(ss, jd) == 0) {
if (verbose_opt)
fprintf(stderr, "mid-transaction streamid %04x collection "
"succeeded\n",
head->streamid & JREC_STREAMID_MASK);
goto retry;
}
fprintf(stderr, "mid-transaction streamid %04x collection failed\n",
head->streamid & JREC_STREAMID_MASK);
jscan_dispose(js);
return(NULL);
} else if (ss->ss_direction == JD_BACKWARDS &&
(head->streamid & JREC_STREAMCTL_END) == 0
) {
if (verbose_opt > 1)
fprintf(stderr, "mid-transaction detected transid %016jx "
"streamid %04x\n",
(uintmax_t)jd->jd_transid,
head->streamid & JREC_STREAMID_MASK);
if (jaddrecord_backtrack(ss, jd) == 0) {
if (verbose_opt)
fprintf(stderr, "mid-transaction streamid %04x "
"collection succeeded\n",
head->streamid & JREC_STREAMID_MASK);
goto retry;
}
fprintf(stderr, "mid-transaction streamid %04x collection failed\n",
head->streamid & JREC_STREAMID_MASK);
jscan_dispose(js);
return(NULL);
}
}
/*
* If we've made it to here and we still don't have a hash record
* to track the transaction, create one.
*/
if (jh == NULL) {
jh = malloc(sizeof(*jh));
bzero(jh, sizeof(*jh));
*jhp = jh;
jh->jh_first = js;
jh->jh_last = js;
jh->jh_transid = head->streamid;
jh->jh_session = ss;
return (NULL);
}
/*
* Emplace the stream segment
*/
jh->jh_transid |= head->streamid & JREC_STREAMCTL_MASK;
if (ss->ss_direction == JD_FORWARDS) {
jh->jh_last->js_next = js;
jh->jh_last = js;
} else {
js->js_next = jh->jh_first;
jh->jh_first = js;
}
/*
* If the transaction is complete, remove the hash entry and return the
* js representing the beginning of the transaction. Otherwise leave
* the hash entry intact and return NULL.
*/
if ((jh->jh_transid & (JREC_STREAMCTL_BEGIN|JREC_STREAMCTL_END)) ==
(JREC_STREAMCTL_BEGIN|JREC_STREAMCTL_END)
) {
*jhp = jh->jh_hash;
js = jh->jh_first;
free(jh);
jnormalize(js);
} else {
js = NULL;
}
return (js);
}
/*
* Renormalize the jscan list to remove all the meta record headers
* and trailers except for the very first one.
*/
static
void
jnormalize(struct jstream *js)
{
struct jstream *jscan;
off_t off;
js->js_normalized_off = 0;
js->js_normalized_base = (void *)js->js_head;
js->js_normalized_size = js->js_head->recsize - sizeof(struct journal_rawrecend);
js->js_normalized_total = js->js_normalized_size;
off = js->js_normalized_size;
for (jscan = js->js_next; jscan; jscan = jscan->js_next) {
jscan->js_normalized_off = off;
jscan->js_normalized_base = (char *)jscan->js_head +
sizeof(struct journal_rawrecbeg);
jscan->js_normalized_size = jscan->js_head->recsize -
sizeof(struct journal_rawrecbeg) -
sizeof(struct journal_rawrecend);
off += jscan->js_normalized_size;
js->js_normalized_total += jscan->js_normalized_size;
}
}
/*
* For sanity's sake I will describe the normal backtracking that must occur,
* but this routine must also operate on reverse-scanned (undo) records
* by forward tracking.
*
* A record has been found that represents the middle or end of a transaction
* when we were expecting the beginning of a transaction. We must backtrack
* to locate the start of the transaction, then process raw records relating
* to the transaction until we reach our current point (jd) again. If
* we find a matching streamid representing the end of a transaction instead
* of the expected start-of-transaction that record belongs to a wholely
* different meta-transaction and the record we seek is known to not be
* available.
*
* jd is the current record, directon is the normal scan direction (we have
* to scan in the reverse direction).
*/
static
int
jaddrecord_backtrack(struct jsession *ss, struct jdata *jd)
{
struct jfile *jf = ss->ss_jfin;
struct jdata *scan;
struct jstream *js;
u_int16_t streamid;
u_int16_t scanid;
assert(ss->ss_direction == JD_FORWARDS || ss->ss_direction == JD_BACKWARDS);
if (jmodes & JMODEF_INPUT_PIPE)
return(-1);
streamid = ((struct journal_rawrecbeg *)jd->jd_data)->streamid & JREC_STREAMID_MASK;
if (ss->ss_direction == JD_FORWARDS) {
/*
* Backtrack in the reverse direction looking for the transaction
* start bit. If we find an end bit instead it belongs to an
* unrelated transaction using the same streamid and there is no
* point continuing.
*/
scan = jref(jd);
while ((scan = jread(jf, scan, JD_BACKWARDS)) != NULL) {
scanid = ((struct journal_rawrecbeg *)scan->jd_data)->streamid;
if ((scanid & JREC_STREAMID_MASK) != streamid)
continue;
if (scanid & JREC_STREAMCTL_END) {
jfree(jf, scan);
return(-1);
}
if (scanid & JREC_STREAMCTL_BEGIN)
break;
}
/*
* Now jaddrecord the related records.
*/
while (scan != NULL && scan->jd_transid < jd->jd_transid) {
scanid = ((struct journal_rawrecbeg *)scan->jd_data)->streamid;
if ((scanid & JREC_STREAMID_MASK) == streamid) {
js = jaddrecord(ss, scan);
assert(js == NULL);
}
scan = jread(jf, scan, JD_FORWARDS);
}
if (scan == NULL)
return(-1);
jfree(jf, scan);
} else {
/*
* Backtrack in the forwards direction looking for the transaction
* end bit. If we find a start bit instead if belongs to an
* unrelated transaction using the same streamid and there is no
* point continuing.
*/
scan = jref(jd);
while ((scan = jread(jf, scan, JD_FORWARDS)) != NULL) {
scanid = ((struct journal_rawrecbeg *)scan->jd_data)->streamid;
if ((scanid & JREC_STREAMID_MASK) != streamid)
continue;
if (scanid & JREC_STREAMCTL_BEGIN) {
jfree(jf, scan);
return(-1);
}
if (scanid & JREC_STREAMCTL_END)
break;
}
/*
* Now jaddrecord the related records.
*/
while (scan != NULL && scan->jd_transid > jd->jd_transid) {
scanid = ((struct journal_rawrecbeg *)scan->jd_data)->streamid;
if ((scanid & JREC_STREAMID_MASK) == streamid) {
js = jaddrecord(ss, scan);
assert(js == NULL);
}
scan = jread(jf, scan, JD_BACKWARDS);
}
if (scan == NULL)
return(-1);
jfree(jf, scan);
}
return(0);
}
void
jscan_dispose(struct jstream *js)
{
struct jstream *jnext;
if (js->js_alloc_buf) {
free(js->js_alloc_buf);
js->js_alloc_buf = NULL;
js->js_alloc_size = 0;
}
while (js) {
jnext = js->js_next;
jfree(js->js_session->ss_jfin, js->js_jdata);
js->js_jdata = NULL;
free(js);
js = jnext;
}
}
/*
* Read the specified block of data out of a linked set of jstream
* structures. Returns 0 on success or an error code on error.
*/
int
jsread(struct jstream *js, off_t off, void *buf, int bytes)
{
const void *ptr;
int n;
while (bytes) {
n = jsreadany(js, off, &ptr);
if (n == 0)
return (ENOENT);
if (n > bytes)
n = bytes;
bcopy(ptr, buf, n);
buf = (char *)buf + n;
off += n;
bytes -= n;
}
return(0);
}
/*
* Read the specified block of data out of a linked set of jstream
* structures. Attempt to return a pointer into the data set but
* allocate and copy if that is not possible. Returns 0 on success
* or an error code on error.
*/
int
jsreadp(struct jstream *js, off_t off, const void **bufp,
int bytes)
{
int error = 0;
int n;
n = jsreadany(js, off, bufp);
if (n < bytes) {
if (js->js_alloc_size < bytes) {
if (js->js_alloc_buf)
free(js->js_alloc_buf);
js->js_alloc_buf = malloc(bytes);
js->js_alloc_size = bytes;
if (js->js_alloc_buf == NULL)
fprintf(stderr, "attempt to allocate %d bytes failed\n", bytes);
assert(js->js_alloc_buf != NULL);
}
error = jsread(js, off, js->js_alloc_buf, bytes);
if (error) {
*bufp = NULL;
} else {
*bufp = js->js_alloc_buf;
}
}
return(error);
}
int
jsreadcallback(struct jstream *js, ssize_t (*func)(int, const void *, size_t),
int fd, off_t off, int bytes)
{
const void *bufp;
int res;
int n;
int r;
res = 0;
while (bytes && (n = jsreadany(js, off, &bufp)) > 0) {
if (n > bytes)
n = bytes;
r = func(fd, bufp, n);
if (r != n) {
if (res == 0)
res = -1;
}
res += n;
bytes -= n;
off += n;
}
return(res);
}
/*
* Return the largest contiguous buffer starting at the specified offset,
* or 0.
*/
int
jsreadany(struct jstream *js, off_t off, const void **bufp)
{
struct jstream *scan;
int n;
if ((scan = js->js_cache) == NULL || scan->js_normalized_off > off)
scan = js;
while (scan && scan->js_normalized_off <= off) {
js->js_cache = scan;
if (scan->js_normalized_off + scan->js_normalized_size > off) {
n = (int)(off - scan->js_normalized_off);
*bufp = scan->js_normalized_base + n;
return(scan->js_normalized_size - n);
}
scan = scan->js_next;
}
return(0);
}
Jump to Line
Something went wrong with that request. Please try again.