From: dan <dan@noemail.net>
Date: Wed, 10 May 2017 16:18:05 +0000 (+0000)
Subject: Fix a problem causing a lock to be held past the end of a transaction. Use a
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=730859568d8757a82bda910328a0af523e4f0c70;p=thirdparty%2Fsqlite.git

Fix a problem causing a lock to be held past the end of a transaction. Use a
blocking lock to take the read-lock on page 1 taken by all transactions.

FossilOrigin-Name: 2584df3d42ece69d37f31f3655cd0d4760914bea73d4f4ccb7f2a7aa47f80f49
---

diff --git a/manifest b/manifest
index 4cacc9c1f5..a23f43ff89 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Use\sa\sblocking\scall\sto\sobtain\sthe\swal-mode\sWRITER\slock\sin\ssome\scases.
-D 2017-05-10T13:46:29.059
+C Fix\sa\sproblem\scausing\sa\slock\sto\sbe\sheld\spast\sthe\send\sof\sa\stransaction.\sUse\sa\nblocking\slock\sto\stake\sthe\sread-lock\son\spage\s1\staken\sby\sall\stransactions.
+D 2017-05-10T16:18:05.140
 F Makefile.in 1cc758ce3374a32425e4d130c2fe7b026b20de5b8843243de75f087c0a2661fb
 F Makefile.linux-gcc 7bc79876b875010e8c8f9502eb935ca92aa3c434
 F Makefile.msc 6a8c838220f7c00820e1fc0ac1bccaaa8e5676067e1dbfa1bafa7a4ffecf8ae6
@@ -389,7 +389,7 @@ F src/os_setup.h 0dbaea40a7d36bf311613d31342e0b99e2536586
 F src/os_unix.c 30e2c43e4955db990e5b5a81e901f8aa74cc8820
 F src/os_win.c 2a6c73eef01c51a048cc4ddccd57f981afbec18a
 F src/os_win.h 7b073010f1451abe501be30d12f6bc599824944a
-F src/pager.c 5326f380451332c254690c577c56a668e18207fb505014d2238bb43cca941148
+F src/pager.c da0832b763a947f0f30d1ac449a6a6eccce5f819929b2256a3a289f1281b1ac8
 F src/pager.h ea05992c581c3366279fb1d436944604b4be17208ebb41fa407306e5e4b34205
 F src/parse.y 0513387ce02fea97897d8caef82d45f347818593f24f1bdc48e0c530a8af122d
 F src/pcache.c 62835bed959e2914edd26afadfecce29ece0e870
@@ -403,7 +403,8 @@ F src/random.c 80f5d666f23feb3e6665a6ce04c7197212a88384
 F src/resolve.c 3e518b962d932a997fae373366880fc028c75706
 F src/rowset.c 7b7e7e479212e65b723bf40128c7b36dc5afdfac
 F src/select.c 4f0adefaa5e9417459b07757e0f6060cac97930a86f0fba9797bab233ced66c0
-F src/server.c 0dc1e45a211636dacc1dff6f8c94e2fcb8a171258797638ef8b8afa803190b66
+F src/server.c e6c06532b238941c317cb406d5d67637774003d50c5b1f03634b5e3b2a6acbbc
+F src/server.h 7b8fec0d6671ac5f0c0f9b42647fa37c0cb87c3165651d0c1cacad0bb02432d2
 F src/shell.c e5950029da103c5d378e71d548759459b9a7fc76177a71562c22082c705745ab
 F src/sqlite.h.in 8d126e4cfbd1f4bc6f4043aacd77f78b45613e7d630185d49a5d099394247483
 F src/sqlite3.rc 5121c9e10c3964d5755191c80dd1180c122fc3a8
@@ -481,7 +482,7 @@ F src/vdbesort.c e72fe02a2121386ba767ede8942e9450878b8fc873abf3d1b6824485f092570
 F src/vdbetrace.c 41963d5376f0349842b5fc4aaaaacd7d9cdc0834
 F src/vtab.c 35b9bdc2b41de32a417141d12097bcc4e29a77ed7cdb8f836d1d2305d946b61b
 F src/vxworks.h d2988f4e5a61a4dfe82c6524dd3d6e4f2ce3cdb9
-F src/wal.c 8db0fb216f08c20da136b521dc294ae28c7ae6658c37460c97ba661735d186f5
+F src/wal.c b78eab7bb45f6c5b59ad90b7825adb2fe10cb3bc73295d2fcdaa61859f078301
 F src/wal.h 739d92494eb18b6d8f3e353e66c10eb8f94534bafd336ece9f3f60235317ea08
 F src/walker.c b71a992b413b3a022572eccf29ef4b4890223791
 F src/where.c c6352f15be5031907c68bcbde96cad1a6da20e9f4051d10168a59235de9a8566
@@ -1114,7 +1115,7 @@ F test/server1.test 46803bd3fe8b99b30dbc5ff38ffc756f5c13a118
 F test/server2.test 11dda300ebef43b4abe0fdc086b6f51b964beddb529fb65bc1f026db5895c36e
 F test/server3.test c33343f2f6bc23f2b4e2f047c3d083579f0cfac2795e0f1eb226ab34758967c0
 F test/servercrash.test 816c132b26af008067cab2913783f67006d4003e3988f3f3ee1075742f6e0a6c
-F test/serverwal.test 968154cee9a7719fa3e6b9b648e7e4d691a8e8ea4f797e13354a6e84fd159d8a
+F test/serverwal.test a162dd5105b0c1d6d68a12224aae06aba06812503396711fdc70f967b9f00f8d
 F test/session.test 78fa2365e93d3663a6e933f86e7afc395adf18be
 F test/shared.test 1da9dbad400cee0d93f252ccf76e1ae007a63746
 F test/shared2.test 03eb4a8d372e290107d34b6ce1809919a698e879
@@ -1583,7 +1584,7 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P 270b7d1eacb57827465946262b31c5c890d7fc5b5618ccd9e220bc2f9546de54
-R 093b295a1ab0adce73d443998b14bdc9
+P 4464ca1d686b5c457995cc885d4a8704e402ad387aa4cc37de199276b28cc08e
+R 8af7c0b56c931c6427bbb46d22a2354a
 U dan
-Z 579dd9e65d85708090977566fef93a28
+Z 9c853b21d10daf349150cf7187819c31
diff --git a/manifest.uuid b/manifest.uuid
index b93192d744..cf91b36b8c 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-4464ca1d686b5c457995cc885d4a8704e402ad387aa4cc37de199276b28cc08e
\ No newline at end of file
+2584df3d42ece69d37f31f3655cd0d4760914bea73d4f4ccb7f2a7aa47f80f49
\ No newline at end of file
diff --git a/src/pager.c b/src/pager.c
index c25173a677..b84bbb6ad9 100644
--- a/src/pager.c
+++ b/src/pager.c
@@ -5393,7 +5393,7 @@ int sqlite3PagerSharedLock(Pager *pPager){
     rc = sqlite3ServerBegin(pPager->pServer);
   }
 #endif
-  if( pagerUseWal(pPager) ){
+  if( rc==SQLITE_OK && pagerUseWal(pPager) ){
     assert( rc==SQLITE_OK );
     rc = pagerBeginReadTransaction(pPager);
   }
diff --git a/src/server.c b/src/server.c
index b1508fc82b..4a2f501be2 100644
--- a/src/server.c
+++ b/src/server.c
@@ -413,7 +413,7 @@ int sqlite3ServerBegin(Server *p){
   int rc = posixLock(p->pHma->fd, p->iClient+1, SERVER_WRITE_LOCK, 1);
   if( rc ) return rc;
 #endif
-  return sqlite3ServerLock(p, 1, 0, 0);
+  return sqlite3ServerLock(p, 1, 0, 1);
 }
 
 /*
@@ -479,14 +479,11 @@ int sqlite3ServerLock(Server *p, Pgno pgno, int bWrite, int bBlock){
     if( bWrite ){
       int iLock = ((int)(v>>HMA_CLIENT_SLOTS)) - 1;
       if( iLock==p->iClient ) goto server_lock_out;
-      if( iLock<0 ){
-        p->aLock[p->nLock++] = pgno;
-      }
     }else{
       if( v & (1<<p->iClient) ) goto server_lock_out;
-      p->aLock[p->nLock++] = pgno;
     }
 
+    p->aLock[p->nLock++] = pgno;
     while( 1 ){
       u32 n;
 
diff --git a/src/server.h b/src/server.h
new file mode 100644
index 0000000000..fe0bc0b380
--- /dev/null
+++ b/src/server.h
@@ -0,0 +1,34 @@
+/*
+** 2017 April 24
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+*/
+
+#ifdef SQLITE_SERVER_EDITION
+
+#ifndef SQLITE_SERVER_H
+#define SQLITE_SERVER_H
+
+
+typedef struct Server Server;
+
+int sqlite3ServerConnect(Pager *pPager, Server **ppOut, int *piClient);
+
+void sqlite3ServerDisconnect(Server *p, sqlite3_file *dbfd);
+
+int sqlite3ServerBegin(Server *p);
+int sqlite3ServerEnd(Server *p);
+int sqlite3ServerReleaseWriteLocks(Server *p);
+
+int sqlite3ServerLock(Server *p, Pgno pgno, int bWrite, int bBlock);
+
+#endif /* SQLITE_SERVER_H */
+
+#endif /* SQLITE_SERVER_EDITION */
diff --git a/src/wal.c b/src/wal.c
index d0776db99b..3a70b29946 100644
--- a/src/wal.c
+++ b/src/wal.c
@@ -2610,7 +2610,7 @@ int sqlite3WalFindFrame(
   /* This routine is only be called from within a read transaction. */
   assert( walIsServer(pWal) || pWal->readLock>=0 || pWal->lockError );
 
-  if( walIsServer(pWal) ){
+  if( walIsServer(pWal) && pWal->writeLock==0 ){
     /* A server mode connection must read from the most recent snapshot. */
     iLast = walIndexHdr(pWal)->mxFrame;
   }
@@ -2812,7 +2812,7 @@ int sqlite3WalEndWriteTransaction(Wal *pWal){
 */
 int sqlite3WalUndo(Wal *pWal, int (*xUndo)(void *, Pgno), void *pUndoCtx){
   int rc = SQLITE_OK;
-  if( ALWAYS(pWal->writeLock) ){
+  if( pWal->writeLock ){
     Pgno iMax = pWal->hdr.mxFrame;
     Pgno iFrame;
   
diff --git a/test/serverwal.test b/test/serverwal.test
index d856e5ea95..abcd78b3be 100644
--- a/test/serverwal.test
+++ b/test/serverwal.test
@@ -86,5 +86,28 @@ do_test 3.1 {
   expr {$N == [file size test.db-wal]}
 } {1}
 
+#-------------------------------------------------------------------------
+# That ROLLBACK appears to work.
+#
+reset_db
+do_execsql_test 4.0 {
+  PRAGMA cache_size = 10;
+  CREATE TABLE ttt(a, b);
+  CREATE INDEX yyy ON ttt(b, a);
+  PRAGMA journal_mode = wal;
+  WITH s(i) AS (
+    SELECT 1 UNION ALL SELECT i+1 FROM s WHERE i<100
+  )
+  INSERT INTO ttt SELECT randomblob(100), randomblob(100) FROM s;
+} {wal}
+
+do_execsql_test 4.1 {
+  PRAGMA integrity_check;
+  BEGIN;
+    UPDATE ttt SET b=a;
+  ROLLBACK;
+  PRAGMA integrity_check;
+} {ok ok}
+
 finish_test