From: drh <>
Date: Sun, 7 May 2023 03:23:32 +0000 (+0000)
Subject: It turns out that pagerExclusiveLock() can be called with the lock state
X-Git-Tag: version-3.42.0~36
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=28f32bedd16b6bb3f90848d3ac3778231eebca34;p=thirdparty%2Fsqlite.git

It turns out that pagerExclusiveLock() can be called with the lock state
already set to RESERVED if the SQLITE_FCNTL_PERSIST_WAL setting is set and
a specific sequence of multiple journal mode changes occur.
Enhance pagerExclusiveLock() to deal with this.
[forum:/forumpost/8130545bc6|Forum post 8130545bc6]

FossilOrigin-Name: 2bb8d977392f635515aa4a36f6f763a2e4858f7adc1120519e2e74c04a9749b5
---

diff --git a/manifest b/manifest
index 7133d0784d..331a35aaec 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Fix\sa\scomment\sin\sthe\sJSON\slogic.\s\sNo\scode\schanges.
-D 2023-05-05T20:22:06.621
+C It\sturns\sout\sthat\spagerExclusiveLock()\scan\sbe\scalled\swith\sthe\slock\sstate\nalready\sset\sto\sRESERVED\sif\sthe\sSQLITE_FCNTL_PERSIST_WAL\ssetting\sis\sset\sand\na\sspecific\ssequence\sof\smultiple\sjournal\smode\schanges\soccur.\nEnhance\spagerExclusiveLock()\sto\sdeal\swith\sthis.\n[forum:/forumpost/8130545bc6|Forum\spost\s8130545bc6]
+D 2023-05-07T03:23:32.841
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724
@@ -622,7 +622,7 @@ F src/os_setup.h 6011ad7af5db4e05155f385eb3a9b4470688de6f65d6166b8956e58a3d87210
 F src/os_unix.c 1b3ddb7814c4bf37f494c04d2ab30c1ced5b2c927267e1930ce7cd388787a96d
 F src/os_win.c 2b2411279f7b24f927591561303fc5871845732df42641cbf695c23640b16975
 F src/os_win.h 7b073010f1451abe501be30d12f6bc599824944a
-F src/pager.c 9d36ddedc842e993c88c222ed914822dbd6f8ece3c648fde04468637012a034a
+F src/pager.c 45e2ef5e9eb5cc0138bcc32b5d2299479be80b206f621873f59149dfb517f496
 F src/pager.h f82e9844166e1585f5786837ddc7709966138ced17f568c16af7ccf946c2baa3
 F src/parse.y 146f9a1db7db5ef4299c6897d335e5abed348c2626190d2877d45ffa210fd4ca
 F src/pcache.c 8ee13acccfd9accbf0af94910b7323dd7f7d55300d92ddafcf40e34fcc8e21be
@@ -1874,7 +1874,7 @@ F test/walhook.test ed00a40ba7255da22d6b66433ab61fab16a63483
 F test/walmode.test cd6e7cff618eaaa5910ce57c3657aa50110397f86213886a2400afb9bfec7b7b
 F test/walnoshm.test 84ca10c544632a756467336b7c3b864d493ee496
 F test/waloverwrite.test dad2f26567f1b45174e54fbf9a8dc1cb876a7f03
-F test/walpersist.test 8c6b7e3ec1ba91b5e4dc4e0921d6d3f87cd356a6
+F test/walpersist.test 8d78a1ec91299163451417b451a2bac3481f8eb9f455b1ca507a6625c927ca6e
 F test/walprotocol.test 1b3f922125e341703f6e946d77fdc564d38fb3e07a9385cfdc6c99cac1ecf878
 F test/walprotocol2.test 7d3b6b4bf0b12f8007121b1e6ef714bc99101fb3b48e46371df1db868eebc131
 F test/walro.test cb438d05ba0d191f10b688e39c4f0cd5b71569a1d1f4440e5bdf3c6880e08c20
@@ -2068,8 +2068,8 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P 910e770ad4d8e8e45bf069af963f2e975bfcfb882578dc5fe714cd2396258934
-R fb2c885eb34d0a9c073f49ec6e0b9a64
+P 3f30ea5ec9d849c64d8c38f4fffbc06c749ecff91ab90bc29b3a3cc9ec5b9df0
+R 50489123bab67876dc44e71aabe4a3c4
 U drh
-Z 083918063f857e50a07fc4bf5f897840
+Z 15666d796dadaefad48a0d98e2e18377
 # Remove this line to create a well-formed Fossil manifest.
diff --git a/manifest.uuid b/manifest.uuid
index 556a9a20a0..a4526c604e 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-3f30ea5ec9d849c64d8c38f4fffbc06c749ecff91ab90bc29b3a3cc9ec5b9df0
\ No newline at end of file
+2bb8d977392f635515aa4a36f6f763a2e4858f7adc1120519e2e74c04a9749b5
\ No newline at end of file
diff --git a/src/pager.c b/src/pager.c
index 063b793f7f..44384de5c0 100644
--- a/src/pager.c
+++ b/src/pager.c
@@ -7473,13 +7473,15 @@ int sqlite3PagerWalSupported(Pager *pPager){
 */
 static int pagerExclusiveLock(Pager *pPager){
   int rc;                         /* Return code */
+  u8 eOrigLock;                   /* Original lock */
 
-  assert( pPager->eLock==SHARED_LOCK || pPager->eLock==EXCLUSIVE_LOCK );
+  assert( pPager->eLock>=SHARED_LOCK );
+  eOrigLock = pPager->eLock;
   rc = pagerLockDb(pPager, EXCLUSIVE_LOCK);
   if( rc!=SQLITE_OK ){
     /* If the attempt to grab the exclusive lock failed, release the 
     ** pending lock that may have been obtained instead.  */
-    pagerUnlockDb(pPager, SHARED_LOCK);
+    pagerUnlockDb(pPager, eOrigLock);
   }
 
   return rc;
diff --git a/test/walpersist.test b/test/walpersist.test
index 692728dda4..73e6de13d4 100644
--- a/test/walpersist.test
+++ b/test/walpersist.test
@@ -121,6 +121,22 @@ do_test walpersist-3.4 {
   sqlite3 db test.db
   execsql { PRAGMA integrity_check }
 } {ok}
- 
+
+# 2023-05-07 https://sqlite.org/forum/forumpost/8130545bc6
+#
+reset_db
+do_test 4.1 {
+  db eval {
+    PRAGMA journal_mode=WAL;
+    CREATE TABLE t1(x);
+  }
+  file_control_persist_wal db 1
+  db eval {
+    PRAGMA journal_mode=TRUNCATE;
+    PRAGMA journal_mode=MEMORY;
+    PRAGMA journal_mode=WAL;
+    PRAGMA journal_mode=PERSIST;
+  }
+} {truncate memory wal persist}
 
 finish_test