int lastErrno; /* The unix errno from the last I/O error */
void *lockingContext; /* Locking style specific state */
UnixUnusedFd *pUnused; /* Pre-allocated UnixUnusedFd */
+ int fileFlags; /* Miscellanous flags */
#if SQLITE_ENABLE_LOCKING_STYLE
int openFlags; /* The flags specified at open() */
#endif
#endif
};
+/*
+** The following macros define bits in unixFile.fileFlags
+*/
+#define SQLITE_WHOLE_FILE_LOCKING 0x0001 /* Use whole-file locking */
+
/*
** Include code that is common to all os_*.c files
*/
return rc;
}
+/*
+** Perform a file locking operation on a range of bytes in a file.
+** The "op" parameter should be one of F_RDLCK, F_WRLCK, or F_UNLCK.
+** Return 0 on success or -1 for failure. On failure, write the error
+** code into *pErrcode.
+**
+** If the SQLITE_WHOLE_FILE_LOCKING bit is clear, then only lock
+** the range of bytes on the locking page between SHARED_FIRST and
+** SHARED_SIZE. If SQLITE_WHOLE_FILE_LOCKING is set, then lock all
+** bytes from 0 up to but not including PENDING_BYTE, and all bytes
+** that follow SHARED_FIRST.
+**
+** In other words, of SQLITE_WHOLE_FILE_LOCKING if false (the historical
+** default case) then only lock a small range of bytes from SHARED_FIRST
+** through SHARED_FIRST+SHARED_SIZE-1. But if SQLITE_WHOLE_FILE_LOCKING is
+** true then lock every byte in the file except for PENDING_BYTE and
+** RESERVED_BYTE.
+**
+** SQLITE_WHOLE_FILE_LOCKING=true overlaps SQLITE_WHOLE_FILE_LOCKING=false
+** and so the locking schemes are compatible. One type of lock will
+** effectively exclude the other type. The reason for using the
+** SQLITE_WHOLE_FILE_LOCKING=true is that by indicating the full range
+** of bytes to be read or written, we give hints to NFS to help it
+** maintain cache coherency. On the other hand, whole file locking
+** is slower, so we don't want to use it except for NFS.
+*/
+static int rangeLock(unixFile *pFile, int op, int *pErrcode){
+ struct flock lock;
+ int rc;
+ lock.l_type = op;
+ lock.l_start = SHARED_FIRST;
+ lock.l_whence = SEEK_SET;
+ if( (pFile->fileFlags & SQLITE_WHOLE_FILE_LOCKING)==0 ){
+ lock.l_len = SHARED_SIZE;
+ rc = fcntl(pFile->h, F_SETLK, &lock);
+ *pErrcode = errno;
+ }else{
+ lock.l_len = 0;
+ rc = fcntl(pFile->h, F_SETLK, &lock);
+ *pErrcode = errno;
+ if( NEVER(op==F_UNLCK) || rc!=(-1) ){
+ lock.l_start = 0;
+ lock.l_len = PENDING_BYTE;
+ rc = fcntl(pFile->h, F_SETLK, &lock);
+ if( ALWAYS(op!=F_UNLCK) && rc==(-1) ){
+ *pErrcode = errno;
+ lock.l_type = F_UNLCK;
+ lock.l_start = SHARED_FIRST;
+ lock.l_len = 0;
+ fcntl(pFile->h, F_SETLK, &lock);
+ }
+ }
+ }
+ return rc;
+}
+
/*
** Lock the file with the lock specified by parameter locktype - one
** of the following:
struct unixLockInfo *pLock = pFile->pLock;
struct flock lock;
int s;
+ int tErrno;
assert( pFile );
OSTRACE7("LOCK %d %s was %s(%s,%d) pid=%d\n", pFile->h,
return SQLITE_OK;
}
- /* Make sure the locking sequence is correct
+ /* Make sure the locking sequence is correct.
+ ** (1) We never move from unlocked to anything higher than shared lock.
+ ** (2) SQLite never explicitly requests a pendig lock.
+ ** (3) A shared lock is always held when a reserve lock is requested.
*/
assert( pFile->locktype!=NO_LOCK || locktype==SHARED_LOCK );
assert( locktype!=PENDING_LOCK );
goto end_lock;
}
- lock.l_len = 1L;
-
- lock.l_whence = SEEK_SET;
/* A PENDING lock is needed before acquiring a SHARED lock and before
** acquiring an EXCLUSIVE lock. For the SHARED lock, the PENDING will
** be released.
*/
+ lock.l_len = 1L;
+ lock.l_whence = SEEK_SET;
if( locktype==SHARED_LOCK
|| (locktype==EXCLUSIVE_LOCK && pFile->locktype<PENDING_LOCK)
){
lock.l_start = PENDING_BYTE;
s = fcntl(pFile->h, F_SETLK, &lock);
if( s==(-1) ){
- int tErrno = errno;
+ tErrno = errno;
rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_LOCK);
if( IS_LOCK_ERROR(rc) ){
pFile->lastErrno = tErrno;
** operating system calls for the specified lock.
*/
if( locktype==SHARED_LOCK ){
- int tErrno = 0;
assert( pLock->cnt==0 );
assert( pLock->locktype==0 );
/* Now get the read-lock */
- lock.l_start = SHARED_FIRST;
- lock.l_len = SHARED_SIZE;
- if( (s = fcntl(pFile->h, F_SETLK, &lock))==(-1) ){
- tErrno = errno;
- }
+ s = rangeLock(pFile, F_RDLCK, &tErrno);
+
/* Drop the temporary PENDING lock */
lock.l_start = PENDING_BYTE;
lock.l_len = 1L;
switch( locktype ){
case RESERVED_LOCK:
lock.l_start = RESERVED_BYTE;
+ s = fcntl(pFile->h, F_SETLK, &lock);
+ tErrno = errno;
break;
case EXCLUSIVE_LOCK:
- lock.l_start = SHARED_FIRST;
- lock.l_len = SHARED_SIZE;
+ s = rangeLock(pFile, F_WRLCK, &tErrno);
break;
default:
assert(0);
}
- s = fcntl(pFile->h, F_SETLK, &lock);
if( s==(-1) ){
- int tErrno = errno;
rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_LOCK);
if( IS_LOCK_ERROR(rc) ){
pFile->lastErrno = tErrno;
** the requested locking level, this routine is a no-op.
*/
static int unixUnlock(sqlite3_file *id, int locktype){
- struct unixLockInfo *pLock;
- struct flock lock;
- int rc = SQLITE_OK;
- unixFile *pFile = (unixFile*)id;
- int h;
+ unixFile *pFile = (unixFile*)id; /* The open file */
+ struct unixLockInfo *pLock; /* Structure describing current lock state */
+ struct flock lock; /* Information passed into fcntl() */
+ int rc = SQLITE_OK; /* Return code from this interface */
+ int h; /* The underlying file descriptor */
+ int tErrno; /* Error code from system call errors */
assert( pFile );
OSTRACE7("UNLOCK %d %d was %d(%d,%d) pid=%d\n", pFile->h, locktype,
if( locktype==SHARED_LOCK ){
- lock.l_type = F_RDLCK;
- lock.l_whence = SEEK_SET;
- lock.l_start = SHARED_FIRST;
- lock.l_len = SHARED_SIZE;
- if( fcntl(h, F_SETLK, &lock)==(-1) ){
- int tErrno = errno;
+ if( rangeLock(pFile, F_RDLCK, &tErrno)==(-1) ){
rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_RDLOCK);
if( IS_LOCK_ERROR(rc) ){
pFile->lastErrno = tErrno;
if( fcntl(h, F_SETLK, &lock)!=(-1) ){
pLock->locktype = SHARED_LOCK;
}else{
- int tErrno = errno;
+ tErrno = errno;
rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_UNLOCK);
if( IS_LOCK_ERROR(rc) ){
pFile->lastErrno = tErrno;
if( fcntl(h, F_SETLK, &lock)!=(-1) ){
pLock->locktype = NO_LOCK;
}else{
- int tErrno = errno;
+ tErrno = errno;
rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_UNLOCK);
if( IS_LOCK_ERROR(rc) ){
pFile->lastErrno = tErrno;
/******************************************************************************
************************* Begin dot-file Locking ******************************
**
-** The dotfile locking implementation uses the existing of separate lock
+** The dotfile locking implementation uses the existance of separate lock
** files in order to control access to the database. This works on just
** about every filesystem imaginable. But there are serious downsides:
**
unixSectorSize, /* xSectorSize */ \
unixDeviceCharacteristics /* xDeviceCapabilities */ \
}; \
-static const sqlite3_io_methods *FINDER##Impl(const char *z, int h){ \
- UNUSED_PARAMETER(z); UNUSED_PARAMETER(h); \
+static const sqlite3_io_methods *FINDER##Impl(const char *z, unixFile *p){ \
+ UNUSED_PARAMETER(z); UNUSED_PARAMETER(p); \
return &METHOD; \
} \
-static const sqlite3_io_methods *(*const FINDER)(const char*,int) \
+static const sqlite3_io_methods *(*const FINDER)(const char*,unixFile *p) \
= FINDER##Impl;
/*
)
#endif
+/*
+** The "Whole File Locking" finder returns the same set of methods as
+** the posix locking finder. But it also sets the SQLITE_WHOLE_FILE_LOCKING
+** flag to force the posix advisory locks to cover the whole file instead
+** of just a small span of bytes near the 1GiB boundary. Whole File Locking
+** is useful on NFS-mounted files since it helps NFS to maintain cache
+** coherency. But it is a detriment to other filesystems since it runs
+** slower.
+*/
+static const sqlite3_io_methods *posixWflIoFinderImpl(const char*z, unixFile*p){
+ UNUSED_PARAMETER(z);
+ p->fileFlags = SQLITE_WHOLE_FILE_LOCKING;
+ return &posixIoMethods;
+}
+static const sqlite3_io_methods
+ *(*const posixWflIoFinder)(const char*,unixFile *p) = posixWflIoFinderImpl;
+
/*
** The proxy locking method is a "super-method" in the sense that it
** opens secondary file descriptors for the conch and lock files and
*/
static const sqlite3_io_methods *autolockIoFinderImpl(
const char *filePath, /* name of the database file */
- int fd /* file descriptor open on the database file */
+ unixFile *pNew /* open file object for the database file */
){
static const struct Mapping {
const char *zFilesystem; /* Filesystem type name */
lockInfo.l_start = 0;
lockInfo.l_whence = SEEK_SET;
lockInfo.l_type = F_RDLCK;
- if( fcntl(fd, F_GETLK, &lockInfo)!=-1 ) {
+ if( fcntl(pNew->h, F_GETLK, &lockInfo)!=-1 ) {
+ pNew->fileFlags = SQLITE_WHOLE_FILE_LOCKING;
return &posixIoMethods;
}else{
return &dotlockIoMethods;
}
}
-static const sqlite3_io_methods *(*const autolockIoFinder)(const char*,int)
- = autolockIoFinderImpl;
+static const sqlite3_io_methods
+ *(*const autolockIoFinder)(const char*,unixFile*) = autolockIoFinderImpl;
#endif /* defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE */
*/
static const sqlite3_io_methods *autolockIoFinderImpl(
const char *filePath, /* name of the database file */
- int fd /* file descriptor open on the database file */
+ unixFile *pNew /* the open file object */
){
struct flock lockInfo;
lockInfo.l_start = 0;
lockInfo.l_whence = SEEK_SET;
lockInfo.l_type = F_RDLCK;
- if( fcntl(fd, F_GETLK, &lockInfo)!=-1 ) {
+ if( fcntl(pNew->h, F_GETLK, &lockInfo)!=-1 ) {
return &posixIoMethods;
}else{
return &semIoMethods;
}
}
-static const sqlite3_io_methods *(*const autolockIoFinder)(const char*,int)
- = autolockIoFinderImpl;
+static const sqlite3_io_methods
+ *(*const autolockIoFinder)(const char*,unixFile*) = autolockIoFinderImpl;
#endif /* OS_VXWORKS && SQLITE_ENABLE_LOCKING_STYLE */
/*
** An abstract type for a pointer to a IO method finder function:
*/
-typedef const sqlite3_io_methods *(*finder_type)(const char*,int);
+typedef const sqlite3_io_methods *(*finder_type)(const char*,unixFile*);
/****************************************************************************
pNew->h = h;
pNew->dirfd = dirfd;
SET_THREADID(pNew);
+ pNew->fileFlags = 0;
#if OS_VXWORKS
pNew->pId = vxworksFindFileId(zFilename);
if( noLock ){
pLockingStyle = &nolockIoMethods;
}else{
- pLockingStyle = (**(finder_type*)pVfs->pAppData)(zFilename, h);
+ pLockingStyle = (**(finder_type*)pVfs->pAppData)(zFilename, pNew);
#if SQLITE_ENABLE_LOCKING_STYLE
/* Cache zFilename in the locking context (AFP and dotlock override) for
** proxyLock activation is possible (remote proxy is based on db name)
#endif
UNIXVFS("unix-none", nolockIoFinder ),
UNIXVFS("unix-dotfile", dotlockIoFinder ),
+ UNIXVFS("unix-wfl", posixWflIoFinder ),
#if OS_VXWORKS
UNIXVFS("unix-namedsem", semIoFinder ),
#endif
projects / thirdparty / sqlite.git / commitdiff
