1*0Sstevel@tonic-gate /*-
2*0Sstevel@tonic-gate * See the file LICENSE for redistribution information.
3*0Sstevel@tonic-gate *
4*0Sstevel@tonic-gate * Copyright (c) 1996, 1997, 1998
5*0Sstevel@tonic-gate * Sleepycat Software. All rights reserved.
6*0Sstevel@tonic-gate */
7*0Sstevel@tonic-gate #include "config.h"
8*0Sstevel@tonic-gate
9*0Sstevel@tonic-gate #ifndef lint
10*0Sstevel@tonic-gate static const char sccsid[] = "@(#)mp_sync.c 10.31 (Sleepycat) 12/11/98";
11*0Sstevel@tonic-gate #endif /* not lint */
12*0Sstevel@tonic-gate
13*0Sstevel@tonic-gate #ifndef NO_SYSTEM_INCLUDES
14*0Sstevel@tonic-gate #include <sys/types.h>
15*0Sstevel@tonic-gate
16*0Sstevel@tonic-gate #include <errno.h>
17*0Sstevel@tonic-gate #include <stdlib.h>
18*0Sstevel@tonic-gate #endif
19*0Sstevel@tonic-gate
20*0Sstevel@tonic-gate #include "db_int.h"
21*0Sstevel@tonic-gate #include "shqueue.h"
22*0Sstevel@tonic-gate #include "db_shash.h"
23*0Sstevel@tonic-gate #include "mp.h"
24*0Sstevel@tonic-gate #include "common_ext.h"
25*0Sstevel@tonic-gate
26*0Sstevel@tonic-gate static int __bhcmp __P((const void *, const void *));
27*0Sstevel@tonic-gate static int __memp_fsync __P((DB_MPOOLFILE *));
28*0Sstevel@tonic-gate
29*0Sstevel@tonic-gate /*
30*0Sstevel@tonic-gate * memp_sync --
31*0Sstevel@tonic-gate * Mpool sync function.
32*0Sstevel@tonic-gate */
33*0Sstevel@tonic-gate int
memp_sync(dbmp,lsnp)34*0Sstevel@tonic-gate memp_sync(dbmp, lsnp)
35*0Sstevel@tonic-gate DB_MPOOL *dbmp;
36*0Sstevel@tonic-gate DB_LSN *lsnp;
37*0Sstevel@tonic-gate {
38*0Sstevel@tonic-gate BH *bhp, **bharray;
39*0Sstevel@tonic-gate DB_ENV *dbenv;
40*0Sstevel@tonic-gate MPOOL *mp;
41*0Sstevel@tonic-gate MPOOLFILE *mfp;
42*0Sstevel@tonic-gate int ar_cnt, nalloc, next, maxpin, ret, wrote;
43*0Sstevel@tonic-gate
44*0Sstevel@tonic-gate MP_PANIC_CHECK(dbmp);
45*0Sstevel@tonic-gate
46*0Sstevel@tonic-gate dbenv = dbmp->dbenv;
47*0Sstevel@tonic-gate mp = dbmp->mp;
48*0Sstevel@tonic-gate
49*0Sstevel@tonic-gate if (dbenv->lg_info == NULL) {
50*0Sstevel@tonic-gate __db_err(dbenv, "memp_sync: requires logging");
51*0Sstevel@tonic-gate return (EINVAL);
52*0Sstevel@tonic-gate }
53*0Sstevel@tonic-gate
54*0Sstevel@tonic-gate /*
55*0Sstevel@tonic-gate * We try and write the buffers in page order: it should reduce seeks
56*0Sstevel@tonic-gate * by the underlying filesystem and possibly reduce the actual number
57*0Sstevel@tonic-gate * of writes. We don't want to hold the region lock while we write
58*0Sstevel@tonic-gate * the buffers, so only hold it lock while we create a list. Get a
59*0Sstevel@tonic-gate * good-size block of memory to hold buffer pointers, we don't want
60*0Sstevel@tonic-gate * to run out.
61*0Sstevel@tonic-gate */
62*0Sstevel@tonic-gate LOCKREGION(dbmp);
63*0Sstevel@tonic-gate nalloc = mp->stat.st_page_dirty + mp->stat.st_page_dirty / 2 + 10;
64*0Sstevel@tonic-gate UNLOCKREGION(dbmp);
65*0Sstevel@tonic-gate
66*0Sstevel@tonic-gate if ((ret = __os_malloc(nalloc * sizeof(BH *), NULL, &bharray)) != 0)
67*0Sstevel@tonic-gate return (ret);
68*0Sstevel@tonic-gate
69*0Sstevel@tonic-gate LOCKREGION(dbmp);
70*0Sstevel@tonic-gate
71*0Sstevel@tonic-gate /*
72*0Sstevel@tonic-gate * If the application is asking about a previous call to memp_sync(),
73*0Sstevel@tonic-gate * and we haven't found any buffers that the application holding the
74*0Sstevel@tonic-gate * pin couldn't write, return yes or no based on the current count.
75*0Sstevel@tonic-gate * Note, if the application is asking about a LSN *smaller* than one
76*0Sstevel@tonic-gate * we've already handled or are currently handling, then we return a
77*0Sstevel@tonic-gate * result based on the count for the larger LSN.
78*0Sstevel@tonic-gate */
79*0Sstevel@tonic-gate if (!F_ISSET(mp, MP_LSN_RETRY) && log_compare(lsnp, &mp->lsn) <= 0) {
80*0Sstevel@tonic-gate if (mp->lsn_cnt == 0) {
81*0Sstevel@tonic-gate *lsnp = mp->lsn;
82*0Sstevel@tonic-gate ret = 0;
83*0Sstevel@tonic-gate } else
84*0Sstevel@tonic-gate ret = DB_INCOMPLETE;
85*0Sstevel@tonic-gate goto done;
86*0Sstevel@tonic-gate }
87*0Sstevel@tonic-gate
88*0Sstevel@tonic-gate /* Else, it's a new checkpoint. */
89*0Sstevel@tonic-gate F_CLR(mp, MP_LSN_RETRY);
90*0Sstevel@tonic-gate
91*0Sstevel@tonic-gate /*
92*0Sstevel@tonic-gate * Save the LSN. We know that it's a new LSN or larger than the one
93*0Sstevel@tonic-gate * for which we were already doing a checkpoint. (BTW, I don't expect
94*0Sstevel@tonic-gate * to see multiple LSN's from the same or multiple processes, but You
95*0Sstevel@tonic-gate * Just Never Know. Responding as if they all called with the largest
96*0Sstevel@tonic-gate * of the LSNs specified makes everything work.)
97*0Sstevel@tonic-gate *
98*0Sstevel@tonic-gate * We don't currently use the LSN we save. We could potentially save
99*0Sstevel@tonic-gate * the last-written LSN in each buffer header and use it to determine
100*0Sstevel@tonic-gate * what buffers need to be written. The problem with this is that it's
101*0Sstevel@tonic-gate * sizeof(LSN) more bytes of buffer header. We currently write all the
102*0Sstevel@tonic-gate * dirty buffers instead.
103*0Sstevel@tonic-gate *
104*0Sstevel@tonic-gate * Walk the list of shared memory segments clearing the count of
105*0Sstevel@tonic-gate * buffers waiting to be written.
106*0Sstevel@tonic-gate */
107*0Sstevel@tonic-gate mp->lsn = *lsnp;
108*0Sstevel@tonic-gate mp->lsn_cnt = 0;
109*0Sstevel@tonic-gate for (mfp = SH_TAILQ_FIRST(&dbmp->mp->mpfq, __mpoolfile);
110*0Sstevel@tonic-gate mfp != NULL; mfp = SH_TAILQ_NEXT(mfp, q, __mpoolfile))
111*0Sstevel@tonic-gate mfp->lsn_cnt = 0;
112*0Sstevel@tonic-gate
113*0Sstevel@tonic-gate /*
114*0Sstevel@tonic-gate * Walk the list of buffers and mark all dirty buffers to be written
115*0Sstevel@tonic-gate * and all pinned buffers to be potentially written (we can't know if
116*0Sstevel@tonic-gate * we'll need to write them until the holding process returns them to
117*0Sstevel@tonic-gate * the cache). We do this in one pass while holding the region locked
118*0Sstevel@tonic-gate * so that processes can't make new buffers dirty, causing us to never
119*0Sstevel@tonic-gate * finish. Since the application may have restarted the sync, clear
120*0Sstevel@tonic-gate * any BH_WRITE flags that appear to be left over from previous calls.
121*0Sstevel@tonic-gate *
122*0Sstevel@tonic-gate * We don't want to pin down the entire buffer cache, otherwise we'll
123*0Sstevel@tonic-gate * starve threads needing new pages. Don't pin down more than 80% of
124*0Sstevel@tonic-gate * the cache.
125*0Sstevel@tonic-gate *
126*0Sstevel@tonic-gate * Keep a count of the total number of buffers we need to write in
127*0Sstevel@tonic-gate * MPOOL->lsn_cnt, and for each file, in MPOOLFILE->lsn_count.
128*0Sstevel@tonic-gate */
129*0Sstevel@tonic-gate ar_cnt = 0;
130*0Sstevel@tonic-gate maxpin = ((mp->stat.st_page_dirty + mp->stat.st_page_clean) * 8) / 10;
131*0Sstevel@tonic-gate for (bhp = SH_TAILQ_FIRST(&mp->bhq, __bh);
132*0Sstevel@tonic-gate bhp != NULL; bhp = SH_TAILQ_NEXT(bhp, q, __bh))
133*0Sstevel@tonic-gate if (F_ISSET(bhp, BH_DIRTY) || bhp->ref != 0) {
134*0Sstevel@tonic-gate F_SET(bhp, BH_WRITE);
135*0Sstevel@tonic-gate
136*0Sstevel@tonic-gate ++mp->lsn_cnt;
137*0Sstevel@tonic-gate
138*0Sstevel@tonic-gate mfp = R_ADDR(dbmp, bhp->mf_offset);
139*0Sstevel@tonic-gate ++mfp->lsn_cnt;
140*0Sstevel@tonic-gate
141*0Sstevel@tonic-gate /*
142*0Sstevel@tonic-gate * If the buffer isn't in use, we should be able to
143*0Sstevel@tonic-gate * write it immediately, so increment the reference
144*0Sstevel@tonic-gate * count to lock it and its contents down, and then
145*0Sstevel@tonic-gate * save a reference to it.
146*0Sstevel@tonic-gate *
147*0Sstevel@tonic-gate * If we've run out space to store buffer references,
148*0Sstevel@tonic-gate * we're screwed. We don't want to realloc the array
149*0Sstevel@tonic-gate * while holding a region lock, so we set the flag to
150*0Sstevel@tonic-gate * force the checkpoint to be done again, from scratch,
151*0Sstevel@tonic-gate * later.
152*0Sstevel@tonic-gate *
153*0Sstevel@tonic-gate * If we've pinned down too much of the cache stop, and
154*0Sstevel@tonic-gate * set a flag to force the checkpoint to be tried again
155*0Sstevel@tonic-gate * later.
156*0Sstevel@tonic-gate */
157*0Sstevel@tonic-gate if (bhp->ref == 0) {
158*0Sstevel@tonic-gate ++bhp->ref;
159*0Sstevel@tonic-gate bharray[ar_cnt] = bhp;
160*0Sstevel@tonic-gate if (++ar_cnt >= nalloc || ar_cnt >= maxpin) {
161*0Sstevel@tonic-gate F_SET(mp, MP_LSN_RETRY);
162*0Sstevel@tonic-gate break;
163*0Sstevel@tonic-gate }
164*0Sstevel@tonic-gate }
165*0Sstevel@tonic-gate } else
166*0Sstevel@tonic-gate if (F_ISSET(bhp, BH_WRITE))
167*0Sstevel@tonic-gate F_CLR(bhp, BH_WRITE);
168*0Sstevel@tonic-gate
169*0Sstevel@tonic-gate /* If there no buffers we can write immediately, we're done. */
170*0Sstevel@tonic-gate if (ar_cnt == 0) {
171*0Sstevel@tonic-gate ret = mp->lsn_cnt ? DB_INCOMPLETE : 0;
172*0Sstevel@tonic-gate goto done;
173*0Sstevel@tonic-gate }
174*0Sstevel@tonic-gate
175*0Sstevel@tonic-gate UNLOCKREGION(dbmp);
176*0Sstevel@tonic-gate
177*0Sstevel@tonic-gate /* Sort the buffers we're going to write. */
178*0Sstevel@tonic-gate qsort(bharray, ar_cnt, sizeof(BH *), __bhcmp);
179*0Sstevel@tonic-gate
180*0Sstevel@tonic-gate LOCKREGION(dbmp);
181*0Sstevel@tonic-gate
182*0Sstevel@tonic-gate /* Walk the array, writing buffers. */
183*0Sstevel@tonic-gate for (next = 0; next < ar_cnt; ++next) {
184*0Sstevel@tonic-gate /*
185*0Sstevel@tonic-gate * It's possible for a thread to have gotten the buffer since
186*0Sstevel@tonic-gate * we listed it for writing. If the reference count is still
187*0Sstevel@tonic-gate * 1, we're the only ones using the buffer, go ahead and write.
188*0Sstevel@tonic-gate * If it's >1, then skip the buffer and assume that it will be
189*0Sstevel@tonic-gate * written when it's returned to the cache.
190*0Sstevel@tonic-gate */
191*0Sstevel@tonic-gate if (bharray[next]->ref > 1) {
192*0Sstevel@tonic-gate --bharray[next]->ref;
193*0Sstevel@tonic-gate continue;
194*0Sstevel@tonic-gate }
195*0Sstevel@tonic-gate
196*0Sstevel@tonic-gate /* Write the buffer. */
197*0Sstevel@tonic-gate mfp = R_ADDR(dbmp, bharray[next]->mf_offset);
198*0Sstevel@tonic-gate ret = __memp_bhwrite(dbmp, mfp, bharray[next], NULL, &wrote);
199*0Sstevel@tonic-gate
200*0Sstevel@tonic-gate /* Release the buffer. */
201*0Sstevel@tonic-gate --bharray[next]->ref;
202*0Sstevel@tonic-gate
203*0Sstevel@tonic-gate /* If there's an error, release the rest of the buffers. */
204*0Sstevel@tonic-gate if (ret != 0 || !wrote) {
205*0Sstevel@tonic-gate /*
206*0Sstevel@tonic-gate * Any process syncing the shared memory buffer pool
207*0Sstevel@tonic-gate * had better be able to write to any underlying file.
208*0Sstevel@tonic-gate * Be understanding, but firm, on this point.
209*0Sstevel@tonic-gate */
210*0Sstevel@tonic-gate if (ret == 0) {
211*0Sstevel@tonic-gate __db_err(dbenv, "%s: unable to flush page: %lu",
212*0Sstevel@tonic-gate __memp_fns(dbmp, mfp),
213*0Sstevel@tonic-gate (u_long)bharray[next]->pgno);
214*0Sstevel@tonic-gate ret = EPERM;
215*0Sstevel@tonic-gate }
216*0Sstevel@tonic-gate
217*0Sstevel@tonic-gate while (++next < ar_cnt)
218*0Sstevel@tonic-gate --bharray[next]->ref;
219*0Sstevel@tonic-gate goto err;
220*0Sstevel@tonic-gate }
221*0Sstevel@tonic-gate }
222*0Sstevel@tonic-gate ret = mp->lsn_cnt != 0 ||
223*0Sstevel@tonic-gate F_ISSET(mp, MP_LSN_RETRY) ? DB_INCOMPLETE : 0;
224*0Sstevel@tonic-gate
225*0Sstevel@tonic-gate done:
226*0Sstevel@tonic-gate if (0) {
227*0Sstevel@tonic-gate err: /*
228*0Sstevel@tonic-gate * On error, clear:
229*0Sstevel@tonic-gate * MPOOL->lsn_cnt (the total sync count)
230*0Sstevel@tonic-gate * MPOOLFILE->lsn_cnt (the per-file sync count)
231*0Sstevel@tonic-gate * BH_WRITE flag (the scheduled for writing flag)
232*0Sstevel@tonic-gate */
233*0Sstevel@tonic-gate mp->lsn_cnt = 0;
234*0Sstevel@tonic-gate for (mfp = SH_TAILQ_FIRST(&dbmp->mp->mpfq, __mpoolfile);
235*0Sstevel@tonic-gate mfp != NULL; mfp = SH_TAILQ_NEXT(mfp, q, __mpoolfile))
236*0Sstevel@tonic-gate mfp->lsn_cnt = 0;
237*0Sstevel@tonic-gate for (bhp = SH_TAILQ_FIRST(&mp->bhq, __bh);
238*0Sstevel@tonic-gate bhp != NULL; bhp = SH_TAILQ_NEXT(bhp, q, __bh))
239*0Sstevel@tonic-gate F_CLR(bhp, BH_WRITE);
240*0Sstevel@tonic-gate }
241*0Sstevel@tonic-gate UNLOCKREGION(dbmp);
242*0Sstevel@tonic-gate __os_free(bharray, nalloc * sizeof(BH *));
243*0Sstevel@tonic-gate return (ret);
244*0Sstevel@tonic-gate }
245*0Sstevel@tonic-gate
246*0Sstevel@tonic-gate /*
247*0Sstevel@tonic-gate * memp_fsync --
248*0Sstevel@tonic-gate * Mpool file sync function.
249*0Sstevel@tonic-gate */
250*0Sstevel@tonic-gate int
memp_fsync(dbmfp)251*0Sstevel@tonic-gate memp_fsync(dbmfp)
252*0Sstevel@tonic-gate DB_MPOOLFILE *dbmfp;
253*0Sstevel@tonic-gate {
254*0Sstevel@tonic-gate DB_MPOOL *dbmp;
255*0Sstevel@tonic-gate int is_tmp;
256*0Sstevel@tonic-gate
257*0Sstevel@tonic-gate dbmp = dbmfp->dbmp;
258*0Sstevel@tonic-gate
259*0Sstevel@tonic-gate MP_PANIC_CHECK(dbmp);
260*0Sstevel@tonic-gate
261*0Sstevel@tonic-gate /*
262*0Sstevel@tonic-gate * If this handle doesn't have a file descriptor that's open for
263*0Sstevel@tonic-gate * writing, or if the file is a temporary, there's no reason to
264*0Sstevel@tonic-gate * proceed further.
265*0Sstevel@tonic-gate */
266*0Sstevel@tonic-gate if (F_ISSET(dbmfp, MP_READONLY))
267*0Sstevel@tonic-gate return (0);
268*0Sstevel@tonic-gate
269*0Sstevel@tonic-gate LOCKREGION(dbmp);
270*0Sstevel@tonic-gate is_tmp = F_ISSET(dbmfp->mfp, MP_TEMP);
271*0Sstevel@tonic-gate UNLOCKREGION(dbmp);
272*0Sstevel@tonic-gate if (is_tmp)
273*0Sstevel@tonic-gate return (0);
274*0Sstevel@tonic-gate
275*0Sstevel@tonic-gate return (__memp_fsync(dbmfp));
276*0Sstevel@tonic-gate }
277*0Sstevel@tonic-gate
278*0Sstevel@tonic-gate /*
279*0Sstevel@tonic-gate * __mp_xxx_fd --
280*0Sstevel@tonic-gate * Return a file descriptor for DB 1.85 compatibility locking.
281*0Sstevel@tonic-gate *
282*0Sstevel@tonic-gate * PUBLIC: int __mp_xxx_fd __P((DB_MPOOLFILE *, int *));
283*0Sstevel@tonic-gate */
284*0Sstevel@tonic-gate int
__mp_xxx_fd(dbmfp,fdp)285*0Sstevel@tonic-gate __mp_xxx_fd(dbmfp, fdp)
286*0Sstevel@tonic-gate DB_MPOOLFILE *dbmfp;
287*0Sstevel@tonic-gate int *fdp;
288*0Sstevel@tonic-gate {
289*0Sstevel@tonic-gate int ret;
290*0Sstevel@tonic-gate
291*0Sstevel@tonic-gate /*
292*0Sstevel@tonic-gate * This is a truly spectacular layering violation, intended ONLY to
293*0Sstevel@tonic-gate * support compatibility for the DB 1.85 DB->fd call.
294*0Sstevel@tonic-gate *
295*0Sstevel@tonic-gate * Sync the database file to disk, creating the file as necessary.
296*0Sstevel@tonic-gate *
297*0Sstevel@tonic-gate * We skip the MP_READONLY and MP_TEMP tests done by memp_fsync(3).
298*0Sstevel@tonic-gate * The MP_READONLY test isn't interesting because we will either
299*0Sstevel@tonic-gate * already have a file descriptor (we opened the database file for
300*0Sstevel@tonic-gate * reading) or we aren't readonly (we created the database which
301*0Sstevel@tonic-gate * requires write privileges). The MP_TEMP test isn't interesting
302*0Sstevel@tonic-gate * because we want to write to the backing file regardless so that
303*0Sstevel@tonic-gate * we get a file descriptor to return.
304*0Sstevel@tonic-gate */
305*0Sstevel@tonic-gate ret = dbmfp->fd == -1 ? __memp_fsync(dbmfp) : 0;
306*0Sstevel@tonic-gate
307*0Sstevel@tonic-gate return ((*fdp = dbmfp->fd) == -1 ? ENOENT : ret);
308*0Sstevel@tonic-gate }
309*0Sstevel@tonic-gate
310*0Sstevel@tonic-gate /*
311*0Sstevel@tonic-gate * __memp_fsync --
312*0Sstevel@tonic-gate * Mpool file internal sync function.
313*0Sstevel@tonic-gate */
314*0Sstevel@tonic-gate static int
__memp_fsync(dbmfp)315*0Sstevel@tonic-gate __memp_fsync(dbmfp)
316*0Sstevel@tonic-gate DB_MPOOLFILE *dbmfp;
317*0Sstevel@tonic-gate {
318*0Sstevel@tonic-gate BH *bhp, **bharray;
319*0Sstevel@tonic-gate DB_MPOOL *dbmp;
320*0Sstevel@tonic-gate MPOOL *mp;
321*0Sstevel@tonic-gate size_t mf_offset;
322*0Sstevel@tonic-gate int ar_cnt, incomplete, nalloc, next, ret, wrote;
323*0Sstevel@tonic-gate
324*0Sstevel@tonic-gate ret = 0;
325*0Sstevel@tonic-gate dbmp = dbmfp->dbmp;
326*0Sstevel@tonic-gate mp = dbmp->mp;
327*0Sstevel@tonic-gate mf_offset = R_OFFSET(dbmp, dbmfp->mfp);
328*0Sstevel@tonic-gate
329*0Sstevel@tonic-gate /*
330*0Sstevel@tonic-gate * We try and write the buffers in page order: it should reduce seeks
331*0Sstevel@tonic-gate * by the underlying filesystem and possibly reduce the actual number
332*0Sstevel@tonic-gate * of writes. We don't want to hold the region lock while we write
333*0Sstevel@tonic-gate * the buffers, so only hold it lock while we create a list. Get a
334*0Sstevel@tonic-gate * good-size block of memory to hold buffer pointers, we don't want
335*0Sstevel@tonic-gate * to run out.
336*0Sstevel@tonic-gate */
337*0Sstevel@tonic-gate LOCKREGION(dbmp);
338*0Sstevel@tonic-gate nalloc = mp->stat.st_page_dirty + mp->stat.st_page_dirty / 2 + 10;
339*0Sstevel@tonic-gate UNLOCKREGION(dbmp);
340*0Sstevel@tonic-gate
341*0Sstevel@tonic-gate if ((ret = __os_malloc(nalloc * sizeof(BH *), NULL, &bharray)) != 0)
342*0Sstevel@tonic-gate return (ret);
343*0Sstevel@tonic-gate
344*0Sstevel@tonic-gate LOCKREGION(dbmp);
345*0Sstevel@tonic-gate
346*0Sstevel@tonic-gate /*
347*0Sstevel@tonic-gate * Walk the LRU list of buffer headers, and get a list of buffers to
348*0Sstevel@tonic-gate * write for this MPOOLFILE.
349*0Sstevel@tonic-gate */
350*0Sstevel@tonic-gate ar_cnt = incomplete = 0;
351*0Sstevel@tonic-gate for (bhp = SH_TAILQ_FIRST(&mp->bhq, __bh);
352*0Sstevel@tonic-gate bhp != NULL; bhp = SH_TAILQ_NEXT(bhp, q, __bh)) {
353*0Sstevel@tonic-gate if (!F_ISSET(bhp, BH_DIRTY) || bhp->mf_offset != mf_offset)
354*0Sstevel@tonic-gate continue;
355*0Sstevel@tonic-gate if (bhp->ref != 0 || F_ISSET(bhp, BH_LOCKED)) {
356*0Sstevel@tonic-gate incomplete = 1;
357*0Sstevel@tonic-gate continue;
358*0Sstevel@tonic-gate }
359*0Sstevel@tonic-gate
360*0Sstevel@tonic-gate ++bhp->ref;
361*0Sstevel@tonic-gate bharray[ar_cnt] = bhp;
362*0Sstevel@tonic-gate
363*0Sstevel@tonic-gate /*
364*0Sstevel@tonic-gate * If we've run out space to store buffer references, we're
365*0Sstevel@tonic-gate * screwed, as we don't want to realloc the array holding a
366*0Sstevel@tonic-gate * region lock. Set the incomplete flag -- the only way we
367*0Sstevel@tonic-gate * can get here is if the file is active in the buffer cache,
368*0Sstevel@tonic-gate * which is the same thing as finding pinned buffers.
369*0Sstevel@tonic-gate */
370*0Sstevel@tonic-gate if (++ar_cnt >= nalloc) {
371*0Sstevel@tonic-gate incomplete = 1;
372*0Sstevel@tonic-gate break;
373*0Sstevel@tonic-gate }
374*0Sstevel@tonic-gate }
375*0Sstevel@tonic-gate
376*0Sstevel@tonic-gate UNLOCKREGION(dbmp);
377*0Sstevel@tonic-gate
378*0Sstevel@tonic-gate /* Sort the buffers we're going to write. */
379*0Sstevel@tonic-gate if (ar_cnt != 0)
380*0Sstevel@tonic-gate qsort(bharray, ar_cnt, sizeof(BH *), __bhcmp);
381*0Sstevel@tonic-gate
382*0Sstevel@tonic-gate LOCKREGION(dbmp);
383*0Sstevel@tonic-gate
384*0Sstevel@tonic-gate /* Walk the array, writing buffers. */
385*0Sstevel@tonic-gate for (next = 0; next < ar_cnt; ++next) {
386*0Sstevel@tonic-gate /*
387*0Sstevel@tonic-gate * It's possible for a thread to have gotten the buffer since
388*0Sstevel@tonic-gate * we listed it for writing. If the reference count is still
389*0Sstevel@tonic-gate * 1, we're the only ones using the buffer, go ahead and write.
390*0Sstevel@tonic-gate * If it's >1, then skip the buffer.
391*0Sstevel@tonic-gate */
392*0Sstevel@tonic-gate if (bharray[next]->ref > 1) {
393*0Sstevel@tonic-gate incomplete = 1;
394*0Sstevel@tonic-gate
395*0Sstevel@tonic-gate --bharray[next]->ref;
396*0Sstevel@tonic-gate continue;
397*0Sstevel@tonic-gate }
398*0Sstevel@tonic-gate
399*0Sstevel@tonic-gate /* Write the buffer. */
400*0Sstevel@tonic-gate ret = __memp_pgwrite(dbmfp, bharray[next], NULL, &wrote);
401*0Sstevel@tonic-gate
402*0Sstevel@tonic-gate /* Release the buffer. */
403*0Sstevel@tonic-gate --bharray[next]->ref;
404*0Sstevel@tonic-gate
405*0Sstevel@tonic-gate /* If there's an error, release the rest of the buffers. */
406*0Sstevel@tonic-gate if (ret != 0) {
407*0Sstevel@tonic-gate while (++next < ar_cnt)
408*0Sstevel@tonic-gate --bharray[next]->ref;
409*0Sstevel@tonic-gate goto err;
410*0Sstevel@tonic-gate }
411*0Sstevel@tonic-gate
412*0Sstevel@tonic-gate /*
413*0Sstevel@tonic-gate * If we didn't write the buffer for some reason, don't return
414*0Sstevel@tonic-gate * success.
415*0Sstevel@tonic-gate */
416*0Sstevel@tonic-gate if (!wrote)
417*0Sstevel@tonic-gate incomplete = 1;
418*0Sstevel@tonic-gate }
419*0Sstevel@tonic-gate
420*0Sstevel@tonic-gate err: UNLOCKREGION(dbmp);
421*0Sstevel@tonic-gate
422*0Sstevel@tonic-gate __os_free(bharray, nalloc * sizeof(BH *));
423*0Sstevel@tonic-gate
424*0Sstevel@tonic-gate /*
425*0Sstevel@tonic-gate * Sync the underlying file as the last thing we do, so that the OS
426*0Sstevel@tonic-gate * has maximal opportunity to flush buffers before we request it.
427*0Sstevel@tonic-gate *
428*0Sstevel@tonic-gate * XXX:
429*0Sstevel@tonic-gate * Don't lock the region around the sync, fsync(2) has no atomicity
430*0Sstevel@tonic-gate * issues.
431*0Sstevel@tonic-gate */
432*0Sstevel@tonic-gate if (ret == 0)
433*0Sstevel@tonic-gate return (incomplete ? DB_INCOMPLETE : __os_fsync(dbmfp->fd));
434*0Sstevel@tonic-gate return (ret);
435*0Sstevel@tonic-gate }
436*0Sstevel@tonic-gate
437*0Sstevel@tonic-gate /*
438*0Sstevel@tonic-gate * memp_trickle --
439*0Sstevel@tonic-gate * Keep a specified percentage of the buffers clean.
440*0Sstevel@tonic-gate */
441*0Sstevel@tonic-gate int
memp_trickle(dbmp,pct,nwrotep)442*0Sstevel@tonic-gate memp_trickle(dbmp, pct, nwrotep)
443*0Sstevel@tonic-gate DB_MPOOL *dbmp;
444*0Sstevel@tonic-gate int pct, *nwrotep;
445*0Sstevel@tonic-gate {
446*0Sstevel@tonic-gate BH *bhp;
447*0Sstevel@tonic-gate MPOOL *mp;
448*0Sstevel@tonic-gate MPOOLFILE *mfp;
449*0Sstevel@tonic-gate db_pgno_t pgno;
450*0Sstevel@tonic-gate u_long total;
451*0Sstevel@tonic-gate int ret, wrote;
452*0Sstevel@tonic-gate
453*0Sstevel@tonic-gate MP_PANIC_CHECK(dbmp);
454*0Sstevel@tonic-gate
455*0Sstevel@tonic-gate mp = dbmp->mp;
456*0Sstevel@tonic-gate if (nwrotep != NULL)
457*0Sstevel@tonic-gate *nwrotep = 0;
458*0Sstevel@tonic-gate
459*0Sstevel@tonic-gate if (pct < 1 || pct > 100)
460*0Sstevel@tonic-gate return (EINVAL);
461*0Sstevel@tonic-gate
462*0Sstevel@tonic-gate LOCKREGION(dbmp);
463*0Sstevel@tonic-gate
464*0Sstevel@tonic-gate /*
465*0Sstevel@tonic-gate * If there are sufficient clean buffers, or no buffers or no dirty
466*0Sstevel@tonic-gate * buffers, we're done.
467*0Sstevel@tonic-gate *
468*0Sstevel@tonic-gate * XXX
469*0Sstevel@tonic-gate * Using st_page_clean and st_page_dirty is our only choice at the
470*0Sstevel@tonic-gate * moment, but it's not as correct as we might like in the presence
471*0Sstevel@tonic-gate * of pools with more than one buffer size, as a free 512-byte buffer
472*0Sstevel@tonic-gate * isn't the same as a free 8K buffer.
473*0Sstevel@tonic-gate */
474*0Sstevel@tonic-gate loop: total = mp->stat.st_page_clean + mp->stat.st_page_dirty;
475*0Sstevel@tonic-gate if (total == 0 || mp->stat.st_page_dirty == 0 ||
476*0Sstevel@tonic-gate (mp->stat.st_page_clean * 100) / total >= (u_long)pct) {
477*0Sstevel@tonic-gate UNLOCKREGION(dbmp);
478*0Sstevel@tonic-gate return (0);
479*0Sstevel@tonic-gate }
480*0Sstevel@tonic-gate
481*0Sstevel@tonic-gate /* Loop until we write a buffer. */
482*0Sstevel@tonic-gate for (bhp = SH_TAILQ_FIRST(&mp->bhq, __bh);
483*0Sstevel@tonic-gate bhp != NULL; bhp = SH_TAILQ_NEXT(bhp, q, __bh)) {
484*0Sstevel@tonic-gate if (bhp->ref != 0 ||
485*0Sstevel@tonic-gate !F_ISSET(bhp, BH_DIRTY) || F_ISSET(bhp, BH_LOCKED))
486*0Sstevel@tonic-gate continue;
487*0Sstevel@tonic-gate
488*0Sstevel@tonic-gate mfp = R_ADDR(dbmp, bhp->mf_offset);
489*0Sstevel@tonic-gate
490*0Sstevel@tonic-gate /*
491*0Sstevel@tonic-gate * We can't write to temporary files -- see the comment in
492*0Sstevel@tonic-gate * mp_bh.c:__memp_bhwrite().
493*0Sstevel@tonic-gate */
494*0Sstevel@tonic-gate if (F_ISSET(mfp, MP_TEMP))
495*0Sstevel@tonic-gate continue;
496*0Sstevel@tonic-gate
497*0Sstevel@tonic-gate pgno = bhp->pgno;
498*0Sstevel@tonic-gate if ((ret = __memp_bhwrite(dbmp, mfp, bhp, NULL, &wrote)) != 0)
499*0Sstevel@tonic-gate goto err;
500*0Sstevel@tonic-gate
501*0Sstevel@tonic-gate /*
502*0Sstevel@tonic-gate * Any process syncing the shared memory buffer pool had better
503*0Sstevel@tonic-gate * be able to write to any underlying file. Be understanding,
504*0Sstevel@tonic-gate * but firm, on this point.
505*0Sstevel@tonic-gate */
506*0Sstevel@tonic-gate if (!wrote) {
507*0Sstevel@tonic-gate __db_err(dbmp->dbenv, "%s: unable to flush page: %lu",
508*0Sstevel@tonic-gate __memp_fns(dbmp, mfp), (u_long)pgno);
509*0Sstevel@tonic-gate ret = EPERM;
510*0Sstevel@tonic-gate goto err;
511*0Sstevel@tonic-gate }
512*0Sstevel@tonic-gate
513*0Sstevel@tonic-gate ++mp->stat.st_page_trickle;
514*0Sstevel@tonic-gate if (nwrotep != NULL)
515*0Sstevel@tonic-gate ++*nwrotep;
516*0Sstevel@tonic-gate goto loop;
517*0Sstevel@tonic-gate }
518*0Sstevel@tonic-gate
519*0Sstevel@tonic-gate /* No more buffers to write. */
520*0Sstevel@tonic-gate ret = 0;
521*0Sstevel@tonic-gate
522*0Sstevel@tonic-gate err: UNLOCKREGION(dbmp);
523*0Sstevel@tonic-gate return (ret);
524*0Sstevel@tonic-gate }
525*0Sstevel@tonic-gate
526*0Sstevel@tonic-gate static int
__bhcmp(p1,p2)527*0Sstevel@tonic-gate __bhcmp(p1, p2)
528*0Sstevel@tonic-gate const void *p1, *p2;
529*0Sstevel@tonic-gate {
530*0Sstevel@tonic-gate BH *bhp1, *bhp2;
531*0Sstevel@tonic-gate
532*0Sstevel@tonic-gate bhp1 = *(BH * const *)p1;
533*0Sstevel@tonic-gate bhp2 = *(BH * const *)p2;
534*0Sstevel@tonic-gate
535*0Sstevel@tonic-gate /* Sort by file (shared memory pool offset). */
536*0Sstevel@tonic-gate if (bhp1->mf_offset < bhp2->mf_offset)
537*0Sstevel@tonic-gate return (-1);
538*0Sstevel@tonic-gate if (bhp1->mf_offset > bhp2->mf_offset)
539*0Sstevel@tonic-gate return (1);
540*0Sstevel@tonic-gate
541*0Sstevel@tonic-gate /*
542*0Sstevel@tonic-gate * !!!
543*0Sstevel@tonic-gate * Defend against badly written quicksort code calling the comparison
544*0Sstevel@tonic-gate * function with two identical pointers (e.g., WATCOM C++ (Power++)).
545*0Sstevel@tonic-gate */
546*0Sstevel@tonic-gate if (bhp1->pgno < bhp2->pgno)
547*0Sstevel@tonic-gate return (-1);
548*0Sstevel@tonic-gate if (bhp1->pgno > bhp2->pgno)
549*0Sstevel@tonic-gate return (1);
550*0Sstevel@tonic-gate return (0);
551*0Sstevel@tonic-gate }
552