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Code Issues

Fixed bug CORE-3535 : Write target of dirty page could be undefined if error happens when nbackup state is changed.

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Also prevent overwriting of first page of allocation table by data page contents.
This commit is contained in:
hvlad 2011-06-24 08:56:43 +00:00
parent 7466ac35e8
commit 44fad53bdb
2 changed files with 62 additions and 32 deletions
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83
src/jrd/nbak.cpp
View File

@ -135,7 +135,7 @@ bool NBackupAllocLock::fetch(thread_db* tdbb)
/******************************** BackupManager::StateWriteGuard ******************************/
BackupManager::StateWriteGuard::StateWriteGuard(thread_db* _tdbb, Jrd::WIN* wnd)
: tdbb(_tdbb), window(NULL)
: tdbb(_tdbb), window(NULL), success(false)
{
Database* dbb = tdbb->getDatabase();
dbb->dbb_backup_manager->beginFlush();
@ -150,6 +150,24 @@ BackupManager::StateWriteGuard::StateWriteGuard(thread_db* _tdbb, Jrd::WIN* wnd)
window = wnd;
}
BackupManager::StateWriteGuard::~StateWriteGuard()
{
// It is important to set state into nbak_state_unknown *before* release of state lock,
// else someone could acquire state lock, fetch and modify some page before state will
// be set into unknown. But dirty page can't be written when backup state is unknown
// because write target (database or delta) is also unknown.
if (!success)
{
NBAK_TRACE( ("invalidate state") );
Database* dbb = tdbb->getDatabase();
dbb->dbb_backup_manager->setState(nbak_state_unknown);
}
releaseHeader();
tdbb->getAttachment()->backupStateWriteUnLock(tdbb);
}
void BackupManager::StateWriteGuard::releaseHeader()
{
if (window)
@ -207,7 +225,8 @@ void BackupManager::beginBackup(thread_db* tdbb)
// Check state
if (backup_state != nbak_state_normal) {
NBAK_TRACE(("end backup - invalid state %d", backup_state));
NBAK_TRACE(("begin backup - invalid state %d", backup_state));
stateGuard.setSuccess();
return;
}
@ -219,13 +238,13 @@ void BackupManager::beginBackup(thread_db* tdbb)
}
catch (const Firebird::Exception&)
{
// no reasons to set it to unknown if we just failed to open difference file
// no reasons to set it to unknown if we just failed to create difference file
stateGuard.setSuccess();
backup_state = nbak_state_normal;
throw;
}
try
{
{ // logical scope
if (database->dbb_flags & (DBB_force_write | DBB_no_fs_cache))
{
PIO_force_write(diff_file,
@ -238,20 +257,27 @@ void BackupManager::beginBackup(thread_db* tdbb)
if (diff_file && geteuid() == 0)
{
struct stat st;
while (fstat(database->dbb_page_manager.findPageSpace(DB_PAGE_SPACE)->file->fil_desc, &st) != 0) {
if (errno != EINTR) {
Firebird::system_call_failed::raise("fstat");
}
PageSpace* pageSpace = database->dbb_page_manager.findPageSpace(DB_PAGE_SPACE);
char* func = NULL;
while (!func && fstat(pageSpace->file->fil_desc, &st) != 0)
{
if (errno != EINTR)
func = "fstat";
}
while (fchown(diff_file->fil_desc, st.st_uid, st.st_gid) != 0) {
if (errno != EINTR) {
Firebird::system_call_failed::raise("fchown");
}
while (!func && fchown(diff_file->fil_desc, st.st_uid, st.st_gid) != 0)
{
if (errno != EINTR)
func = "fchown";
}
while (fchmod(diff_file->fil_desc, st.st_mode) != 0) {
if (errno != EINTR) {
Firebird::system_call_failed::raise("fchmod");
}
while (!func && fchmod(diff_file->fil_desc, st.st_mode) != 0)
{
if (errno != EINTR)
func = "fchmod";
}
if (func)
{
stateGuard.setSuccess();
Firebird::system_call_failed::raise(func);
}
}
#endif
@ -276,18 +302,13 @@ void BackupManager::beginBackup(thread_db* tdbb)
reinterpret_cast<const UCHAR*>(&guid));
stateGuard.releaseHeader();
stateGuard.setSuccess();
backup_state = newState;
current_scn = adjusted_scn;
// All changes go to the difference file now
}
catch (const Firebird::Exception&)
{
NBAK_TRACE( ("invalidate state E1") );
backup_state = nbak_state_unknown;
throw;
}
}
@ -377,6 +398,7 @@ void BackupManager::endBackup(thread_db* tdbb, bool recover)
if ( (recover || backup_state != nbak_state_stalled) && (backup_state != nbak_state_merge ) )
{
stateGuard.setSuccess();
NBAK_TRACE(("invalid state %d", backup_state));
endLock.unlockWrite(tdbb);
return;
@ -396,10 +418,9 @@ void BackupManager::endBackup(thread_db* tdbb, bool recover)
// Adjust state
header->hdr_flags = (header->hdr_flags & ~Ods::hdr_backup_mask) | backup_state;
NBAK_TRACE(("Setting state %d in header page is over", backup_state));
stateGuard.setSuccess();
}
catch (const Firebird::Exception&) {
NBAK_TRACE( ("invalidate state E2") );
backup_state = nbak_state_unknown;
endLock.unlockWrite(tdbb);
throw;
}
@ -466,6 +487,7 @@ void BackupManager::endBackup(thread_db* tdbb, bool recover)
NBAK_TRACE(("new SCN=%d is getting written to header", header->hdr_header.pag_scn));
stateGuard.releaseHeader();
stateGuard.setSuccess();
// Page allocation table cache is no longer valid
NBAK_TRACE(("Dropping alloc table"));
@ -482,8 +504,6 @@ void BackupManager::endBackup(thread_db* tdbb, bool recover)
endLock.unlockWrite(tdbb);
}
catch (const Firebird::Exception&) {
NBAK_TRACE( ("invalidate state E3") );
backup_state = nbak_state_unknown;
endLock.unlockWrite(tdbb);
throw;
}
@ -624,6 +644,15 @@ ULONG BackupManager::allocateDifferencePage(thread_db* tdbb, ULONG db_page)
bool BackupManager::writeDifference(ISC_STATUS* status, ULONG diff_page, Ods::pag* page)
{
if (!diff_page)
{
// We should never be here but if it happens let not overwrite first allocation
// page with garbage.
(Arg::Gds(isc_random) << "Can't allocate difference page").copyTo(status);
return false;
}
NBAK_TRACE(("write_diff"));
BufferDesc temp_bdb;
temp_bdb.bdb_page = diff_page;

11
src/jrd/nbak.h
View File

@ -186,13 +186,13 @@ public:
{
public:
StateWriteGuard(thread_db* _tdbb, Jrd::WIN* wnd);
~StateWriteGuard()
{
releaseHeader();
tdbb->getAttachment()->backupStateWriteUnLock(tdbb);
}
~StateWriteGuard();
void releaseHeader();
void setSuccess()
{
success = true;
}
private:
// copying is prohibited
@ -201,6 +201,7 @@ public:
thread_db* tdbb;
Jrd::WIN* window;
bool success;
};
class StateReadGuard