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Partial handling of incomplete log entries. (It detects when the log file does not end at the right byte, but doesn't checksum, or otherwise look for

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sectors that didn't make it to disk.)
This commit is contained in:
Sears Russell 2006-07-21 01:06:35 +00:00
parent 5c5eeab3f6
commit eb13531c0f
1 changed files with 21 additions and 3 deletions
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24
src/lladd/logger/logWriter.c
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@ -138,7 +138,8 @@ int openLogWriter() {
synchronous disk writes. Therefore, all read accesses (and synchronous disk writes. Therefore, all read accesses (and
therefore all seeks) run through the second descriptor. */ therefore all seeks) run through the second descriptor. */
int logFD = open (LOG_FILE, O_CREAT | O_WRONLY | O_APPEND | O_SYNC, S_IRWXU | S_IRWXG | S_IRWXO); // int logFD = open (LOG_FILE, O_CREAT | O_WRONLY | O_APPEND | O_SYNC, S_IRWXU | S_IRWXG | S_IRWXO);
int logFD = open (LOG_FILE, O_CREAT | O_WRONLY | O_SYNC, S_IRWXU | S_IRWXG | S_IRWXO);
if(logFD == -1) { if(logFD == -1) {
perror("Couldn't open log file for append.\n"); perror("Couldn't open log file for append.\n");
abort(); abort();
@ -224,6 +225,8 @@ int openLogWriter() {
nextAvailableLSN = le->LSN + sizeofLogEntry(le) + sizeof(lsn_t);; nextAvailableLSN = le->LSN + sizeofLogEntry(le) + sizeof(lsn_t);;
FreeLogEntry(le); FreeLogEntry(le);
} }
// If there was a short write at the end of the log, just reuse its lsn, and overwrite it.
fseek(log, nextAvailableLSN, SEEK_SET);
return 0; return 0;
} }
@ -375,8 +378,17 @@ static LogEntry * readLogEntry() {
abort(); abort();
return (LogEntry*)LLADD_IO_ERROR; return (LogEntry*)LLADD_IO_ERROR;
} else { } else {
lsn_t newSize = size - bytesRead;
lsn_t newBytesRead = read (roLogFD, ((byte*)ret)+bytesRead, newSize);
if(newBytesRead == 0) {
return NULL;
}
fprintf(stderr, "short read from log. Expected %ld bytes, got %ld.\nFIXME: This is 'normal', but currently not handled", sizeof(lsn_t), bytesRead); fprintf(stderr, "short read from log. Expected %ld bytes, got %ld.\nFIXME: This is 'normal', but currently not handled", sizeof(lsn_t), bytesRead);
fflush(stderr); fflush(stderr);
fprintf(stderr, "\nattempt to read again produced newBytesRead = %ld, newSize was %ld\n", newBytesRead, newSize);
fflush(stderr);
abort(); // really abort here. This code should attempt to piece together short log reads... abort(); // really abort here. This code should attempt to piece together short log reads...
} }
} }
@ -398,12 +410,18 @@ static LogEntry * readLogEntry() {
abort(); abort();
return (LogEntry*)LLADD_IO_ERROR; return (LogEntry*)LLADD_IO_ERROR;
} else { } else {
fprintf(stderr, "short read from log w/ lsn %ld. Expected %ld bytes, got %ld.\nFIXME: This is 'normal', but currently not handled", debug_lsn, size, bytesRead);
fflush(stderr);
lsn_t newSize = size - bytesRead; lsn_t newSize = size - bytesRead;
lsn_t newBytesRead = read (roLogFD, ((byte*)ret)+bytesRead, newSize); lsn_t newBytesRead = read (roLogFD, ((byte*)ret)+bytesRead, newSize);
if(newBytesRead == 0) {
return NULL;
}
fprintf(stderr, "short read from log w/ lsn %ld. Expected %ld bytes, got %ld.\nFIXME: This is 'normal', but currently not handled", debug_lsn, size, bytesRead);
fflush(stderr);
fprintf(stderr, "\nattempt to read again produced newBytesRead = %ld, newSize was %ld\n", newBytesRead, newSize); fprintf(stderr, "\nattempt to read again produced newBytesRead = %ld, newSize was %ld\n", newBytesRead, newSize);
fflush(stderr); fflush(stderr);
abort(); abort();
return (LogEntry*)LLADD_IO_ERROR; return (LogEntry*)LLADD_IO_ERROR;
} }