-
-#if CACHE != 0
-/**
- * This version implements a primitive cache that greatly improves performance of most
- * filesystems under VirtualBox, and slightly improves it on a handful of other systems.
- */
-#define CACHE_SIZE 131072 /* 128KiB */
-fsw_status_t fsw_efi_read_block(struct fsw_volume *vol, fsw_u32 phys_bno, void *buffer)
-{
- EFI_STATUS Status = EFI_SUCCESS;
- FSW_VOLUME_DATA *Volume = (FSW_VOLUME_DATA *)vol->host_data;
- static fsw_u8 *Cache = NULL;
- static fsw_u64 CacheStart = 0;
- static BOOLEAN CacheValid = FALSE;
- static FSW_VOLUME_DATA *PrevVol = NULL;
- fsw_u64 StartRead = (fsw_u64) phys_bno * vol->phys_blocksize;
-
-// FSW_MSG_DEBUGV((FSW_MSGSTR("fsw_efi_read_block: %d (%d)\n"), phys_bno, vol->phys_blocksize));
-
- if (Cache == NULL) {
- Cache = AllocatePool(CACHE_SIZE);
- }
-
- if ((PrevVol != Volume) || (StartRead < CacheStart) || ((StartRead + vol->phys_blocksize) > CacheStart + CACHE_SIZE)) {
- CacheStart = StartRead;
- CacheValid = FALSE;
- PrevVol = Volume;
- }
-
- // read from disk
- if (!CacheValid && (Cache != NULL)) {
- Status = refit_call5_wrapper(Volume->DiskIo->ReadDisk, Volume->DiskIo, Volume->MediaId,
- StartRead, CACHE_SIZE, Cache);
- if (!EFI_ERROR(Status))
- CacheValid = TRUE;
- } // if (!CacheValid)
-
- if (CacheValid) {
- if (buffer != NULL) {
- CopyMem(buffer, &Cache[StartRead - CacheStart], vol->phys_blocksize);
- } else {
- Status = EFI_BAD_BUFFER_SIZE;
- } // if/else buffer OK
- } else {
- // Unable to use cache; load without cache....
- Status = refit_call5_wrapper(Volume->DiskIo->ReadDisk, Volume->DiskIo, Volume->MediaId,
- (UINT64)phys_bno * vol->phys_blocksize,
- vol->phys_blocksize,
- buffer);
- } // if/else CacheValid
-
- Volume->LastIOStatus = Status;
- if (EFI_ERROR(Status))
- return FSW_IO_ERROR;
- return FSW_SUCCESS;
-}
-#else
-/**
- * This version is the original, which does NOT implement a cache. It performs badly under
- * VirtualBox, but I'm still using it for ext2fs because there seems to be a glitch in the
- * ext2fs driver that causes a loop that repeatedly re-reads pairs of sectors, and the
- * primitive cache in the preceding code just makes that worse.
- */
-fsw_status_t fsw_efi_read_block(struct fsw_volume *vol, fsw_u32 phys_bno, void *buffer)
-{
- EFI_STATUS Status;
- FSW_VOLUME_DATA *Volume = (FSW_VOLUME_DATA *)vol->host_data;
-
-// FSW_MSG_DEBUGV((FSW_MSGSTR("fsw_efi_read_block: %d (%d)\n"), phys_bno, vol->phys_blocksize));
-
- // read from disk
- Status = refit_call5_wrapper(Volume->DiskIo->ReadDisk, Volume->DiskIo, Volume->MediaId,
- (UINT64)phys_bno * vol->phys_blocksize,
- vol->phys_blocksize,
- buffer);
+fsw_status_t fsw_efi_read_block(struct fsw_volume *vol, fsw_u64 phys_bno, void *buffer) {
+ int i, ReadCache = -1;
+ FSW_VOLUME_DATA *Volume = (FSW_VOLUME_DATA *)vol->host_data;
+ EFI_STATUS Status = EFI_SUCCESS;
+ BOOLEAN ReadOneBlock = FALSE;
+ fsw_u64 StartRead = phys_bno * vol->phys_blocksize;
+
+ if (buffer == NULL)
+ return (fsw_status_t) EFI_BAD_BUFFER_SIZE;
+
+ // Initialize static data structures, if necessary....
+ if (LastRead < 0) {
+ fsw_efi_clear_cache();
+ } // if
+
+ // Look for a cache hit on the current query....
+ i = 0;
+ do {
+ if ((Caches[i].Volume == Volume) &&
+ (Caches[i].CacheValid == TRUE) &&
+ (StartRead >= Caches[i].CacheStart) &&
+ ((StartRead + vol->phys_blocksize) <= (Caches[i].CacheStart + CACHE_SIZE))) {
+ ReadCache = i;
+ }
+ i++;
+ } while ((i < NUM_CACHES) && (ReadCache < 0));
+
+ // No cache hit found; load new cache and pass it on....
+ if (ReadCache < 0) {
+ if (LastRead == -1)
+ LastRead = 1;
+ ReadCache = 1 - LastRead; // NOTE: If NUM_CACHES > 2, this must become more complex
+ Caches[ReadCache].CacheValid = FALSE;
+ if (Caches[ReadCache].Cache == NULL)
+ Caches[ReadCache].Cache = AllocatePool(CACHE_SIZE);
+ if (Caches[ReadCache].Cache != NULL) {
+ Status = refit_call5_wrapper(Volume->DiskIo->ReadDisk, Volume->DiskIo, Volume->MediaId,
+ StartRead, CACHE_SIZE, Caches[ReadCache].Cache);
+ if (!EFI_ERROR(Status)) {
+ Caches[ReadCache].CacheStart = StartRead;
+ Caches[ReadCache].CacheValid = TRUE;
+ Caches[ReadCache].Volume = Volume;
+ LastRead = ReadCache;
+ } else {
+ ReadOneBlock = TRUE;
+ }
+ } else {
+ ReadOneBlock = TRUE;
+ } // if cache memory allocated
+ } // if (ReadCache < 0)
+
+ if (Caches[ReadCache].Cache != NULL && Caches[ReadCache].CacheValid == TRUE) {
+ CopyMem(buffer, &Caches[ReadCache].Cache[StartRead - Caches[ReadCache].CacheStart], vol->phys_blocksize);
+ } else {
+ ReadOneBlock = TRUE;
+ }
+
+ if (ReadOneBlock) { // Something's failed, so try a simple disk read of one block....
+ Status = refit_call5_wrapper(Volume->DiskIo->ReadDisk, Volume->DiskIo, Volume->MediaId,
+ phys_bno * vol->phys_blocksize,
+ vol->phys_blocksize,
+ buffer);
+ }