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Overview
| Comment: | Add compiler hints to disable TSAN for the routines that access the -shm file header in WAL mode using a double-read with memory barrier. |
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| Downloads: | Tarball | ZIP archive | SQL archive |
| Timelines: | family | ancestors | descendants | both | trunk |
| Files: | files | file ages | folders |
| SHA3-256: |
3117c1b5a9e348fd8d16ba9d03fdafaa |
| User & Date: | drh 2020-05-19 15:51:10 |
Context
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2020-05-20
| ||
| 15:02 | Back out the change from [7fab1393c2b22b1f] that tries to convert invalid surrogate characters in UTF16 into the replacement character 0xfffd, as we find that this breaks some software. check-in: 4218c7b71f user: drh tags: trunk | |
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2020-05-19
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| 15:51 | Add compiler hints to disable TSAN for the routines that access the -shm file header in WAL mode using a double-read with memory barrier. check-in: 3117c1b5a9 user: drh tags: trunk | |
| 15:40 | In os_win.c, avoid calling sqlite3_uri_boolean() on anything other than a main-db filename. check-in: cb0a18e64f user: dan tags: trunk | |
Changes
Changes to src/wal.c.
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*/
static void walShmBarrier(Wal *pWal){
if( pWal->exclusiveMode!=WAL_HEAPMEMORY_MODE ){
sqlite3OsShmBarrier(pWal->pDbFd);
}
}
/*
** Write the header information in pWal->hdr into the wal-index.
**
** The checksum on pWal->hdr is updated before it is written.
*/
static void walIndexWriteHdr(Wal *pWal){
volatile WalIndexHdr *aHdr = walIndexHdr(pWal);
const int nCksum = offsetof(WalIndexHdr, aCksum);
assert( pWal->writeLock );
pWal->hdr.isInit = 1;
pWal->hdr.iVersion = WALINDEX_MAX_VERSION;
walChecksumBytes(1, (u8*)&pWal->hdr, nCksum, 0, pWal->hdr.aCksum);
................................................................................
** If and only if the read is consistent and the header is different from
** pWal->hdr, then pWal->hdr is updated to the content of the new header
** and *pChanged is set to 1.
**
** If the checksum cannot be verified return non-zero. If the header
** is read successfully and the checksum verified, return zero.
*/
static int walIndexTryHdr(Wal *pWal, int *pChanged){
u32 aCksum[2]; /* Checksum on the header content */
WalIndexHdr h1, h2; /* Two copies of the header content */
WalIndexHdr volatile *aHdr; /* Header in shared memory */
/* The first page of the wal-index must be mapped at this point. */
assert( pWal->nWiData>0 && pWal->apWiData[0] );
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*/
static void walShmBarrier(Wal *pWal){
if( pWal->exclusiveMode!=WAL_HEAPMEMORY_MODE ){
sqlite3OsShmBarrier(pWal->pDbFd);
}
}
/*
** Add the SQLITE_NO_TSAN as part of the return-type of a function
** definition as a hint that the function contains constructs that
** might give false-positive TSAN warnings.
**
** See tag-20200519-1.
*/
#if defined(__clang__) && !defined(SQLITE_NO_TSAN)
# define SQLITE_NO_TSAN __attribute__((no_sanitize_thread))
#else
# define SQLITE_NO_TSAN
#endif
/*
** Write the header information in pWal->hdr into the wal-index.
**
** The checksum on pWal->hdr is updated before it is written.
*/
static SQLITE_NO_TSAN void walIndexWriteHdr(Wal *pWal){
volatile WalIndexHdr *aHdr = walIndexHdr(pWal);
const int nCksum = offsetof(WalIndexHdr, aCksum);
assert( pWal->writeLock );
pWal->hdr.isInit = 1;
pWal->hdr.iVersion = WALINDEX_MAX_VERSION;
walChecksumBytes(1, (u8*)&pWal->hdr, nCksum, 0, pWal->hdr.aCksum);
................................................................................
** If and only if the read is consistent and the header is different from
** pWal->hdr, then pWal->hdr is updated to the content of the new header
** and *pChanged is set to 1.
**
** If the checksum cannot be verified return non-zero. If the header
** is read successfully and the checksum verified, return zero.
*/
static SQLITE_NO_TSAN int walIndexTryHdr(Wal *pWal, int *pChanged){
u32 aCksum[2]; /* Checksum on the header content */
WalIndexHdr h1, h2; /* Two copies of the header content */
WalIndexHdr volatile *aHdr; /* Header in shared memory */
/* The first page of the wal-index must be mapped at this point. */
assert( pWal->nWiData>0 && pWal->apWiData[0] );
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