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When creating a new journal file, open a (read-only) file descriptor on the

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directory containing the journal and sync that directory once to make sure
that the journal filename entry gets into the directory.  Ticket #410. (CVS 1066)

FossilOrigin-Name: 09c10fe3c99cffc64ed02c2929f206d99c8e3309
This commit is contained in:
drh
2003-07-27 18:59:42 +00:00
parent 98e3e60012
commit a76c82eb0d
5 changed files with 78 additions and 13 deletions
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55
src/os.c
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@@ -326,6 +326,7 @@ int sqliteOsOpenReadWrite(
int *pReadonly
){
#if OS_UNIX
id->dirfd = -1;
id->fd = open(zFilename, O_RDWR|O_CREAT|O_LARGEFILE|O_BINARY, 0644);
if( id->fd<0 ){
id->fd = open(zFilename, O_RDONLY|O_LARGEFILE|O_BINARY);
@@ -450,6 +451,7 @@ int sqliteOsOpenExclusive(const char *zFilename, OsFile *id, int delFlag){
if( access(zFilename, 0)==0 ){
return SQLITE_CANTOPEN;
}
id->dirfd = -1;
id->fd = open(zFilename,
O_RDWR|O_CREAT|O_EXCL|O_NOFOLLOW|O_LARGEFILE|O_BINARY, 0600);
if( id->fd<0 ){
@@ -536,6 +538,7 @@ int sqliteOsOpenExclusive(const char *zFilename, OsFile *id, int delFlag){
*/
int sqliteOsOpenReadOnly(const char *zFilename, OsFile *id){
#if OS_UNIX
id->dirfd = -1;
id->fd = open(zFilename, O_RDONLY|O_LARGEFILE|O_BINARY);
if( id->fd<0 ){
return SQLITE_CANTOPEN;
@@ -597,6 +600,42 @@ int sqliteOsOpenReadOnly(const char *zFilename, OsFile *id){
#endif
}
/*
** Attempt to open a file descriptor for the directory that contains a
** file. This file descriptor can be used to fsync() the directory
** in order to make sure the creation of a new file is actually written
** to disk.
**
** This routine is only meaningful for Unix. It is a no-op under
** windows since windows does not support hard links.
**
** On success, a handle for a previously open file is at *id is
** updated with the new directory file descriptor and SQLITE_OK is
** returned.
**
** On failure, the function returns SQLITE_CANTOPEN and leaves
** *id unchanged.
*/
int sqliteOsOpenDirectory(
const char *zDirname,
OsFile *id
){
#if OS_UNIX
if( id->fd<0 ){
/* Do not open the directory if the corresponding file is not already
** open. */
return SQLITE_CANTOPEN;
}
assert( id->dirfd<0 );
id->dirfd = open(zDirname, O_RDONLY|O_BINARY, 0644);
if( id->dirfd<0 ){
return SQLITE_CANTOPEN;
}
TRACE3("OPENDIR %-3d %s\n", id->dirfd, zDirname);
#endif
return SQLITE_OK;
}
/*
** Create a temporary file name in zBuf. zBuf must be big enough to
** hold at least SQLITE_TEMPNAME_SIZE characters.
@@ -706,6 +745,8 @@ int sqliteOsTempFileName(char *zBuf){
int sqliteOsClose(OsFile *id){
#if OS_UNIX
close(id->fd);
if( id->dirfd>=0 ) close(id->dirfd);
id->dirfd = -1;
sqliteOsEnterMutex();
releaseLockInfo(id->pLock);
sqliteOsLeaveMutex();
@@ -892,6 +933,14 @@ int sqliteOsSeek(OsFile *id, off_t offset){
/*
** Make sure all writes to a particular file are committed to disk.
**
** Under Unix, also make sure that the directory entry for the file
** has been created by fsync-ing the directory that contains the file.
** If we do not do this and we encounter a power failure, the directory
** entry for the journal might not exist after we reboot. The next
** SQLite to access the file will not know that the journal exists (because
** the directory entry for the journal was never created) and the transaction
** will not roll back - possibly leading to database corruption.
*/
int sqliteOsSync(OsFile *id){
#if OS_UNIX
@@ -900,6 +949,12 @@ int sqliteOsSync(OsFile *id){
if( fsync(id->fd) ){
return SQLITE_IOERR;
}else{
if( id->dirfd>=0 ){
TRACE2("DIRSYNC %-3d\n", id->dirfd);
fsync(id->dirfd);
close(id->dirfd); /* Only need to sync once, so close the directory */
id->dirfd = -1; /* when we are done. */
}
return SQLITE_OK;
}
#endif