1,6 → 1,6 |
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; |
;; ;; |
;; Copyright (C) KolibriOS team 2011-2012. All rights reserved. ;; |
;; Copyright (C) KolibriOS team 2011-2014. All rights reserved. ;; |
;; Distributed under terms of the GNU General Public License ;; |
;; ;; |
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; |
7,6 → 7,489 |
|
$Revision$ |
|
; Read/write functions try to do large operations, |
; it is significantly faster than several small operations. |
; This requires large buffers. |
; We can't use input/output buffers directly - they can be controlled |
; by user-mode application, so they can be modified between the operation |
; and copying to/from cache, giving invalid data in cache. |
; It is unclear how to use cache directly, currently cache items are |
; allocated/freed sector-wise, so items for sequential sectors can be |
; scattered over all the cache. |
; So read/write functions allocate a temporary buffer which is |
; 1) not greater than half of free memory and |
; 2) not greater than the following constant. |
CACHE_MAX_ALLOC_SIZE = 4 shl 20 |
|
; Legacy interface for filesystems fs_{read,write}32_{sys,app} |
; gives only one sector for FS. However, per-sector reading is inefficient, |
; so internally fs_read32_{sys,app} reads to the cache several sequential |
; sectors, hoping that they will be useful. |
; Total number of sectors is given by the following constant. |
CACHE_LEGACY_READ_SIZE = 16 |
|
; This structure describes one item in the cache. |
struct CACHE_ITEM |
SectorLo dd ? ; low 32 bits of sector |
SectorHi dd ? ; high 32 bits of sector |
Status dd ? ; one of CACHE_ITEM_* |
ends |
|
; Possible values for CACHE_ITEM_* |
CACHE_ITEM_EMPTY = 0 |
CACHE_ITEM_COPY = 1 |
CACHE_ITEM_MODIFIED = 2 |
|
; Read several sequential sectors using cache #1. |
; in: edx:eax = start sector, relative to start of partition |
; in: ecx = number of sectors to read |
; in: ebx -> buffer |
; in: ebp -> PARTITION |
; out: eax = error code, 0 = ok |
; out: ecx = number of sectors that were read |
fs_read64_sys: |
; Save ebx, set ebx to SysCache and let the common part do its work. |
push ebx |
mov ebx, [ebp+PARTITION.Disk] |
add ebx, DISK.SysCache |
jmp fs_read64_common |
|
; Read several sequential sectors using cache #2. |
; in: edx:eax = start sector, relative to start of partition |
; in: ecx = number of sectors to read |
; in: edi -> buffer |
; in: ebp -> PARTITION |
; out: eax = error code, 0 = ok |
; out: ecx = number of sectors that were read |
fs_read64_app: |
; Save ebx, set ebx to AppCache and let the common part do its work. |
push ebx |
mov ebx, [ebp+PARTITION.Disk] |
add ebx, DISK.AppCache |
|
; Common part of fs_read64_{app,sys}: |
; read several sequential sectors using the given cache. |
fs_read64_common: |
; 1. Setup stack frame. |
push esi edi ; save used registers to be stdcall |
push 0 ; initialize .error_code |
push ebx edx eax ecx ecx ; initialize stack variables |
virtual at esp |
.local_vars: |
.num_sectors_orig dd ? |
; Number of sectors that should be read. Used to generate output value of ecx. |
.num_sectors dd ? |
; Number of sectors that remain to be read. Decreases from .num_sectors_orig to 0. |
.sector_lo dd ? ; low 32 bits of the current sector |
.sector_hi dd ? ; high 32 bits of the current sector |
.cache dd ? ; pointer to DISKCACHE |
.error_code dd ? ; current status |
.local_vars_size = $ - .local_vars |
.saved_regs rd 2 |
.buffer dd ? ; filled by fs_read64_{sys,app} |
end virtual |
; 2. Validate parameters against partition length: |
; immediately return error if edx:eax are beyond partition end, |
; decrease .num_sectors and .num_sectors_orig, if needed, |
; so that the entire operation fits in the partition limits. |
mov eax, dword [ebp+PARTITION.Length] |
mov edx, dword [ebp+PARTITION.Length+4] |
sub eax, [.sector_lo] |
sbb edx, [.sector_hi] |
jb .end_of_media |
jnz .no_end_of_media |
cmp ecx, eax |
jbe .no_end_of_media |
; If .num_sectors got decreased, set status to DISK_STATUS_END_OF_MEDIA; |
; if all subsequent operations would be successful, this would become the final |
; status, otherwise this would be rewritten by failed operation. |
mov [.num_sectors], eax |
mov [.num_sectors_orig], eax |
mov [.error_code], DISK_STATUS_END_OF_MEDIA |
.no_end_of_media: |
; 3. If number of sectors to read is zero, either because zero-sectors operation |
; was requested or because it got decreased to zero due to partition limits, |
; just return the current status. |
cmp [.num_sectors], 0 |
jz .return |
; 4. Shift sector from partition-relative to absolute. |
mov eax, dword [ebp+PARTITION.FirstSector] |
mov edx, dword [ebp+PARTITION.FirstSector+4] |
add [.sector_lo], eax |
adc [.sector_hi], edx |
; 5. If the cache is disabled, pass the request directly to the driver. |
mov edi, [.buffer] |
cmp [ebx+DISKCACHE.pointer], 0 |
jz .nocache |
; 6. Look for sectors in the cache, sequentially from the beginning. |
; Stop at the first sector that is not in the cache |
; or when all sectors were read from the cache. |
; 6a. Acquire the lock. |
mov ecx, [ebp+PARTITION.Disk] |
add ecx, DISK.CacheLock |
call mutex_lock |
.lookup_in_cache_loop: |
; 6b. For each sector, call the lookup function without adding to the cache. |
mov eax, [.sector_lo] |
mov edx, [.sector_hi] |
call cache_lookup_read |
; 6c. If it has failed, the sector is not in cache; |
; release the lock and go to 7. |
jc .not_found_in_cache |
; The sector is found in cache. |
; 6d. Copy data for the caller. |
; Note that buffer in edi is advanced automatically. |
mov esi, ecx |
shl esi, 9 |
add esi, [ebx+DISKCACHE.data] |
mov ecx, 512/4 |
rep movsd |
; 6e. Advance the sector. |
add [.sector_lo], 1 |
adc [.sector_hi], 0 |
; 6f. Decrement number of sectors left. |
; If all sectors were read, release the lock and return. |
dec [.num_sectors] |
jnz .lookup_in_cache_loop |
; Release the lock acquired at 6a. |
mov ecx, [ebp+PARTITION.Disk] |
add ecx, DISK.CacheLock |
call mutex_unlock |
.return: |
mov eax, [.error_code] |
mov ecx, [.num_sectors_orig] |
sub ecx, [.num_sectors] |
.nothing: |
add esp, .local_vars_size |
pop edi esi ebx ; restore used registers to be stdcall |
ret |
.not_found_in_cache: |
; Release the lock acquired at 6a. |
mov ecx, [ebp+PARTITION.Disk] |
add ecx, DISK.CacheLock |
call mutex_unlock |
; The current sector is not present in the cache. |
; Ask the driver to read all requested not-yet-read sectors, |
; put results in the cache. |
; Also, see the comment before the definition of CACHE_MAX_ALLOC_SIZE. |
; 7. Allocate buffer for operations. |
; Normally, create buffer that is sufficient for all remaining data. |
; However, for extra-large requests make an upper limit: |
; do not use more than half of the free memory |
; or more than CACHE_MAX_ALLOC_SIZE bytes. |
mov ebx, [pg_data.pages_free] |
shr ebx, 1 |
jz .nomemory |
cmp ebx, CACHE_MAX_ALLOC_SIZE shr 12 |
jbe @f |
mov ebx, CACHE_MAX_ALLOC_SIZE shr 12 |
@@: |
shl ebx, 12 - 9 |
cmp ebx, [.num_sectors] |
jbe @f |
mov ebx, [.num_sectors] |
@@: |
mov eax, ebx |
shl eax, 9 |
stdcall kernel_alloc, eax |
; If failed, return the appropriate error code. |
test eax, eax |
jz .nomemory |
mov esi, eax |
; Split the request to chunks that fit in the allocated buffer. |
.read_loop: |
; 8. Get iteration size: either size of allocated buffer in sectors |
; or number of sectors left, select what is smaller. |
cmp ebx, [.num_sectors] |
jbe @f |
mov ebx, [.num_sectors] |
@@: |
; 9. Create second portion of local variables. |
; Note that variables here and above are esp-relative; |
; it means that all addresses should be corrected when esp is changing. |
push ebx esi esi |
push ebx |
; In particular, num_sectors is now [.num_sectors+.local_vars2_size]. |
virtual at esp |
.local_vars2: |
.current_num_sectors dd ? ; number of sectors that were read |
.current_buffer dd ? |
; pointer inside .allocated_buffer that points |
; to the beginning of not-processed data |
.allocated_buffer dd ? ; saved in safe place |
.iteration_size dd ? ; saved in safe place |
.local_vars2_size = $ - .local_vars2 |
end virtual |
; 10. Call the driver, reading the next chunk. |
push esp ; numsectors |
push [.sector_hi+.local_vars2_size+4] ; startsector |
push [.sector_lo+.local_vars2_size+8] ; startsector |
push esi ; buffer |
mov esi, [ebp+PARTITION.Disk] |
mov al, DISKFUNC.read |
call disk_call_driver |
; If failed, save error code. |
test eax, eax |
jz @f |
mov [.error_code], eax |
@@: |
; 11. Copy data for the caller. |
; Note that buffer in edi is advanced automatically. |
cmp [.current_num_sectors], 0 |
jz .copy_done |
mov ecx, [.current_num_sectors] |
shl ecx, 9-2 |
mov esi, [.allocated_buffer] |
rep movsd |
; 12. Copy data to the cache. |
; 12a. Acquire the lock. |
mov ebx, [.cache+.local_vars2_size] |
mov ecx, [ebp+PARTITION.Disk] |
add ecx, DISK.CacheLock |
call mutex_lock |
; 12b. Prepare for the loop: save edi and create a local variable that |
; stores number of sectors to be copied. |
push edi |
push [.current_num_sectors] |
.store_to_cache: |
; 12c. For each sector, call the lookup function with adding to the cache, if not yet. |
mov eax, [.sector_lo+.local_vars2_size+8] |
mov edx, [.sector_hi+.local_vars2_size+8] |
call cache_lookup_write |
test eax, eax |
jnz .cache_error |
; 12d. For each sector, copy data, mark the item as not-modified copy of the disk, |
; advance .current_buffer and .sector_hi:.sector_lo to the next sector. |
mov [esi+CACHE_ITEM.Status], CACHE_ITEM_COPY |
mov esi, [.current_buffer+8] |
mov edi, ecx |
shl edi, 9 |
add edi, [ebx+DISKCACHE.data] |
mov ecx, 512/4 |
rep movsd |
mov [.current_buffer+8], esi |
add [.sector_lo+.local_vars2_size+8], 1 |
adc [.sector_hi+.local_vars2_size+8], 0 |
; 12e. Continue the loop 12c-12d until all sectors are read. |
dec dword [esp] |
jnz .store_to_cache |
.cache_error: |
; 12f. Restore after the loop: pop the local variable and restore edi. |
pop ecx |
pop edi |
; 12g. Release the lock. |
mov ecx, [ebp+PARTITION.Disk] |
add ecx, DISK.CacheLock |
call mutex_unlock |
.copy_done: |
; 13. Remove portion of local variables created at step 9. |
pop ecx |
pop esi esi ebx |
; 14. Continue iterations while number of sectors read by the driver |
; is equal to number of sectors requested and there are additional sectors. |
cmp ecx, ebx |
jnz @f |
sub [.num_sectors], ebx |
jnz .read_loop |
@@: |
; 15. Free the buffer allocated at step 7 and return. |
stdcall kernel_free, esi |
jmp .return |
|
; Special branches: |
.nomemory: |
; memory allocation failed at step 7: return the corresponding error |
mov [.error_code], DISK_STATUS_NO_MEMORY |
jmp .return |
.nocache: |
; step 5, after correcting number of sectors to fit in partition limits |
; and advancing partition-relative sector to absolute, |
; sees that cache is disabled: pass corrected request to the driver |
lea eax, [.num_sectors] |
push eax ; numsectors |
push [.sector_hi+4] ; startsector |
push [.sector_lo+8] ; startsector |
push edi ; buffer |
mov esi, [ebp+PARTITION.Disk] |
mov al, DISKFUNC.read |
call disk_call_driver |
test eax, eax |
jnz @f |
mov eax, [.error_code] |
@@: |
mov ecx, [.num_sectors] |
jmp .nothing |
.end_of_media: |
; requested sector is beyond the partition end: return the corresponding error |
mov [.error_code], DISK_STATUS_END_OF_MEDIA |
jmp .return |
|
; Write several sequential sectors using cache #1. |
; in: edx:eax = start sector |
; in: ecx = number of sectors to write |
; in: ebx -> buffer |
; in: ebp -> PARTITION |
; out: eax = error code, 0 = ok |
; out: ecx = number of sectors that were written |
fs_write64_sys: |
; Save ebx, set ebx to SysCache and let the common part do its work. |
push ebx |
mov ebx, [ebp+PARTITION.Disk] |
add ebx, DISK.SysCache |
jmp fs_write64_common |
|
; Write several sequential sectors using cache #2. |
; in: edx:eax = start sector |
; in: ecx = number of sectors to write |
; in: ebx -> buffer |
; in: ebp -> PARTITION |
; out: eax = error code, 0 = ok |
; out: ecx = number of sectors that were written |
fs_write64_app: |
; Save ebx, set ebx to AppCache and let the common part do its work. |
push ebx |
mov ebx, [ebp+PARTITION.Disk] |
add ebx, DISK.AppCache |
|
; Common part of fs_write64_{app,sys}: |
; write several sequential sectors using the given cache. |
fs_write64_common: |
; 1. Setup stack frame. |
push esi edi ; save used registers to be stdcall |
push 0 ; initialize .error_code |
push edx eax ecx ecx ; initialize stack variables |
push [.buffer-4] ; copy [.buffer] to [.cur_buffer] |
; -4 is due to esp-relative addressing |
virtual at esp |
.local_vars: |
.cur_buffer dd ? ; pointer to data that are currently copying |
.num_sectors_orig dd ? |
; Number of sectors that should be written. Used to generate output value of ecx. |
.num_sectors dd ? |
; Number of sectors that remain to be written. |
.sector_lo dd ? ; low 32 bits of the current sector |
.sector_hi dd ? ; high 32 bits of the current sector |
.error_code dd ? ; current status |
.local_vars_size = $ - .local_vars |
.saved_regs rd 2 |
.buffer dd ? ; filled by fs_write64_{sys,app} |
end virtual |
; 2. Validate parameters against partition length: |
; immediately return error if edx:eax are beyond partition end, |
; decrease .num_sectors and .num_sectors_orig, if needed, |
; so that the entire operation fits in the partition limits. |
mov eax, dword [ebp+PARTITION.Length] |
mov edx, dword [ebp+PARTITION.Length+4] |
sub eax, [.sector_lo] |
sbb edx, [.sector_hi] |
jb .end_of_media |
jnz .no_end_of_media |
cmp ecx, eax |
jbe .no_end_of_media |
; If .num_sectors got decreased, set status to DISK_STATUS_END_OF_MEDIA; |
; if all subsequent operations would be successful, this would become the final |
; status, otherwise this would be rewritten by failed operation. |
mov [.num_sectors], eax |
mov [.num_sectors_orig], eax |
mov [.error_code], DISK_STATUS_END_OF_MEDIA |
.no_end_of_media: |
; 3. If number of sectors to write is zero, either because zero-sectors operation |
; was requested or because it got decreased to zero due to partition limits, |
; just return the current status. |
cmp [.num_sectors], 0 |
jz .return |
; 4. Shift sector from partition-relative to absolute. |
mov eax, dword [ebp+PARTITION.FirstSector] |
mov edx, dword [ebp+PARTITION.FirstSector+4] |
add [.sector_lo], eax |
adc [.sector_hi], edx |
; 5. If the cache is disabled, pass the request directly to the driver. |
cmp [ebx+DISKCACHE.pointer], 0 |
jz .nocache |
; 6. Store sectors in the cache, sequentially from the beginning. |
; 6a. Acquire the lock. |
mov ecx, [ebp+PARTITION.Disk] |
add ecx, DISK.CacheLock |
call mutex_lock |
.lookup_in_cache_loop: |
; 6b. For each sector, call the lookup function with adding to the cache, if not yet. |
mov eax, [.sector_lo] |
mov edx, [.sector_hi] |
call cache_lookup_write |
test eax, eax |
jnz .cache_error |
; 6c. For each sector, copy data, mark the item as modified and not saved, |
; advance .current_buffer to the next sector. |
mov [esi+CACHE_ITEM.Status], CACHE_ITEM_MODIFIED |
mov esi, [.cur_buffer] |
mov edi, ecx |
shl edi, 9 |
add edi, [ebx+DISKCACHE.data] |
mov ecx, 512/4 |
rep movsd |
mov [.cur_buffer], esi |
; 6d. Remove the sector from the other cache. |
; Normally it should not be there, but prefetching could put to the app cache |
; data that normally should belong to the sys cache and vice versa. |
; Note: this requires that both caches must be protected by the same lock. |
mov eax, [.sector_lo] |
mov edx, [.sector_hi] |
push ebx |
sub ebx, [ebp+PARTITION.Disk] |
xor ebx, DISK.SysCache xor DISK.AppCache |
add ebx, [ebp+PARTITION.Disk] |
call cache_lookup_read |
jc @f |
mov [esi+CACHE_ITEM.Status], CACHE_ITEM_EMPTY |
@@: |
pop ebx |
; 6e. Advance .sector_hi:.sector_lo to the next sector. |
add [.sector_lo], 1 |
adc [.sector_hi], 0 |
; 6f. Continue the loop at 6b-6e until all sectors are processed. |
dec [.num_sectors] |
jnz .lookup_in_cache_loop |
.unlock_return: |
; 6g. Release the lock and return. |
mov ecx, [ebp+PARTITION.Disk] |
add ecx, DISK.CacheLock |
call mutex_unlock |
.return: |
mov eax, [.error_code] |
mov ecx, [.num_sectors_orig] |
sub ecx, [.num_sectors] |
.nothing: |
add esp, .local_vars_size |
pop edi esi ebx |
ret |
|
; Special branches: |
.cache_error: |
; error at flushing the cache while adding sector to the cache: |
; return the error from the lookup function |
mov [.error_code], eax |
jmp .unlock_return |
.end_of_media: |
; requested sector is beyond the partition end: return the corresponding error |
mov eax, DISK_STATUS_END_OF_MEDIA |
xor ecx, ecx |
jmp .nothing |
.nocache: |
; step 5, after correcting number of sectors to fit in partition limits |
; and advancing partition-relative sector to absolute, |
; sees that cache is disabled: pass corrected request to the driver |
lea eax, [.num_sectors] |
push eax ; numsectors |
push [.sector_hi+4] ; startsector |
push [.sector_lo+8] ; startsector |
push [.buffer+12] ; buffer |
mov esi, [ebp+PARTITION.Disk] |
mov al, DISKFUNC.write |
call disk_call_driver |
mov ecx, [.num_sectors] |
jmp .nothing |
|
; Legacy. Use fs_read64_sys instead. |
; This function is intended to replace the old 'hd_read' function when |
; [hdd_appl_data] = 0, so its input/output parameters are the same, except |
; that it can't use the global variables 'hd_error' and 'hdd_appl_data'. |
14,12 → 497,13 |
; eax is relative to partition start |
; out: eax = error code; 0 = ok |
fs_read32_sys: |
; Save ecx, set ecx to SysCache and let the common part do its work. |
push ecx |
mov ecx, [ebp+PARTITION.Disk] |
add ecx, DISK.SysCache |
; Save ebx, set ebx to SysCache and let the common part do its work. |
push ebx |
mov ebx, [ebp+PARTITION.Disk] |
add ebx, DISK.SysCache |
jmp fs_read32_common |
|
; Legacy. Use fs_read64_app instead. |
; This function is intended to replace the old 'hd_read' function when |
; [hdd_appl_data] = 1, so its input/output parameters are the same, except |
; that it can't use the global variables 'hd_error' and 'hdd_appl_data'. |
27,10 → 511,10 |
; eax is relative to partition start |
; out: eax = error code; 0 = ok |
fs_read32_app: |
; Save ecx, set ecx to AppCache and let the common part do its work. |
push ecx |
mov ecx, [ebp+PARTITION.Disk] |
add ecx, DISK.AppCache |
; Save ebx, set ebx to AppCache and let the common part do its work. |
push ebx |
mov ebx, [ebp+PARTITION.Disk] |
add ebx, DISK.AppCache |
|
; This label is the common part of fs_read32_sys and fs_read32_app. |
fs_read32_common: |
41,119 → 525,215 |
cmp dword [ebp+PARTITION.Length], eax |
ja @f |
mov eax, DISK_STATUS_END_OF_MEDIA |
pop ecx |
pop ebx |
ret |
@@: |
; 2. Get the absolute sector on the disk. |
push edx esi |
push ecx edx esi edi |
xor edx, edx |
add eax, dword [ebp+PARTITION.FirstSector] |
adc edx, dword [ebp+PARTITION.FirstSector+4] |
; 3. If there is no cache for this disk, just pass the request to the driver. |
cmp [ecx+DISKCACHE.pointer], 0 |
cmp [ebx+DISKCACHE.pointer], 0 |
jnz .scancache |
push 1 |
push esp ; numsectors |
push edx ; startsector |
push eax ; startsector |
push ebx ; buffer |
pushd [esp+32]; buffer |
mov esi, [ebp+PARTITION.Disk] |
mov al, DISKFUNC.read |
call disk_call_driver |
pop ecx |
pop esi edx |
pop ecx |
pop edi esi edx ecx |
pop ebx |
ret |
.scancache: |
; 4. Scan the cache. |
push edi ecx ; scan cache |
push edx eax |
push ebx edx eax |
virtual at esp |
.local_vars: |
.sector_lo dd ? |
.sector_hi dd ? |
.cache dd ? |
.local_vars_size = $ - .local_vars |
.saved_regs rd 4 |
.buffer dd ? |
end virtual |
; The following code is inherited from hd_read. The differences are: |
; all code is protected by the cache lock; instead of static calls |
; to hd_read_dma/hd_read_pio/bd_read the dynamic call to DISKFUNC.read is used; |
; sector is 64-bit, not 32-bit. |
; 4. Scan for the requested sector in the cache. |
; If found, copy the data and return. |
; 4a. Acquire the lock. |
mov ecx, [ebp+PARTITION.Disk] |
add ecx, DISK.CacheLock |
call mutex_lock |
; 4b. Call the lookup function without adding to the cache. |
mov eax, [.sector_lo] |
mov edx, [.sector_hi] |
mov esi, [ecx+DISKCACHE.pointer] |
mov ecx, [ecx+DISKCACHE.sad_size] |
add esi, 12 |
|
mov edi, 1 |
|
.hdreadcache: |
|
cmp dword [esi+8], 0 ; empty |
je .nohdcache |
|
cmp [esi], eax ; correct sector |
jne .nohdcache |
cmp [esi+4], edx ; correct sector |
je .yeshdcache |
|
.nohdcache: |
|
add esi, 12 |
inc edi |
dec ecx |
jnz .hdreadcache |
|
mov esi, [.cache] |
call find_empty_slot64 ; ret in edi |
call cache_lookup_read |
; If not found, go to 5. |
jc .not_found_in_cache |
.found_in_cache: |
; 4c. Copy the data. |
mov edi, [.buffer] |
mov esi, ecx |
shl esi, 9 |
add esi, [ebx+DISKCACHE.data] |
mov ecx, 512/4 |
rep movsd |
; 4d. Release the lock and return success. |
mov ecx, [ebp+PARTITION.Disk] |
add ecx, DISK.CacheLock |
call mutex_unlock |
.return: |
xor eax, eax |
.return_eax: |
add esp, .local_vars_size |
pop edi esi edx ecx |
pop ebx |
ret |
.not_found_in_cache: |
; 5. Decide whether we need to prefetch further sectors. |
; If so, advance to 6. If not, go to 13. |
; Assume that devices < 3MB are floppies which are slow |
; (ramdisk does not have a cache, so we don't even get here for ramdisk). |
; This is a dirty hack, but the entire function is somewhat hacky. Use fs_read64*. |
mov eax, [ebp+PARTITION.Disk] |
cmp dword [eax+DISK.MediaInfo.Capacity+4], 0 |
jnz @f |
cmp dword [eax+DISK.MediaInfo.Capacity], 3 shl (20-9) |
jb .floppy |
@@: |
; We want to prefetch CACHE_LEGACY_READ_SIZE sectors. |
; 6. Release the lock acquired at step 4a. |
mov ecx, [ebp+PARTITION.Disk] |
add ecx, DISK.CacheLock |
call mutex_unlock |
; 7. Allocate buffer for CACHE_LEGACY_READ_SIZE sectors. |
stdcall kernel_alloc, CACHE_LEGACY_READ_SIZE shl 9 |
; If failed, return the corresponding error code. |
test eax, eax |
jnz .read_done |
jz .nomemory |
; 8. Create second portion of local variables. |
push eax eax |
push CACHE_LEGACY_READ_SIZE |
virtual at esp |
.local_vars2: |
.num_sectors dd ? ; number of sectors left |
.current_buffer dd ? ; pointer to data that are currently copying |
.allocated_buffer dd ? ; saved at safe place |
.local_vars2_size = $ - .local_vars2 |
end virtual |
; 9. Call the driver to read CACHE_LEGACY_READ_SIZE sectors. |
push esp ; numsectors |
push [.sector_hi+.local_vars2_size+4] ; startsector |
push [.sector_lo+.local_vars2_size+8] ; startsector |
push eax ; buffer |
mov esi, [ebp+PARTITION.Disk] |
mov al, DISKFUNC.read |
call disk_call_driver |
; Note: we're ok if at least one sector is read, |
; read error somewhere after that just limits data to be put in cache. |
cmp [.num_sectors], 0 |
jz .read_error |
; 10. Copy data for the caller. |
mov esi, [.allocated_buffer] |
mov edi, [.buffer+.local_vars2_size] |
mov ecx, 512/4 |
rep movsd |
; 11. Store all sectors that were successfully read to the cache. |
; 11a. Acquire the lock. |
mov ecx, [ebp+PARTITION.Disk] |
add ecx, DISK.CacheLock |
call mutex_lock |
.store_to_cache: |
; 11b. For each sector, call the lookup function with adding to the cache, if not yet. |
mov eax, [.sector_lo+.local_vars2_size] |
mov edx, [.sector_hi+.local_vars2_size] |
call cache_lookup_write |
test eax, eax |
jnz .cache_error |
; 11c. For each sector, copy data, mark the item as not-modified copy of the disk, |
; advance .current_buffer and .sector_hi:.sector_lo to the next sector. |
mov [esi+CACHE_ITEM.Status], CACHE_ITEM_COPY |
mov esi, [.current_buffer] |
mov edi, ecx |
shl edi, 9 |
add edi, [ebx+DISKCACHE.data] |
mov ecx, 512/4 |
rep movsd |
mov [.current_buffer], esi |
add [.sector_lo+.local_vars2_size], 1 |
adc [.sector_hi+.local_vars2_size], 0 |
; 11d. Continue the loop at 11b-11c until all sectors are processed. |
dec [.num_sectors] |
jnz .store_to_cache |
.cache_error: |
; 11e. Release the lock. |
mov ecx, [ebp+PARTITION.Disk] |
add ecx, DISK.CacheLock |
call mutex_unlock |
.copy_done: |
; 12. Remove portion of local variables created at step 8, |
; free the buffer allocated at step 7 and return. |
pop ecx ecx |
stdcall kernel_free |
jmp .return |
.read_error: |
; If no sectors were read, free the buffer allocated at step 7 |
; and pass the error to the caller. |
push eax |
stdcall kernel_free, [.allocated_buffer+4] |
pop eax |
add esp, .local_vars2_size |
jmp .return_eax |
.nomemory: |
mov eax, DISK_STATUS_NO_MEMORY |
jmp .return_eax |
.floppy: |
; We don't want to prefetch anything, just read one sector. |
; We are still holding the lock acquired at step 4a. |
; 13. Call the lookup function adding sector to the cache. |
call cache_lookup_write |
test eax, eax |
jnz .floppy_cache_error |
; 14. Mark the item as empty for the case of read error. |
mov [esi+CACHE_ITEM.Status], CACHE_ITEM_EMPTY |
push ecx |
|
; 15. Call the driver to read one sector. |
push 1 |
push esp |
push edx |
push [.sector_lo+12] |
mov ecx, [.cache+16] |
mov eax, edi |
shl eax, 9 |
add eax, [ecx+DISKCACHE.data] |
push eax |
push [.sector_lo+16] |
shl ecx, 9 |
add ecx, [ebx+DISKCACHE.data] |
push ecx |
mov esi, [ebp+PARTITION.Disk] |
mov al, DISKFUNC.read |
call disk_call_driver |
pop ecx |
dec ecx |
jnz .read_done |
jnz .floppy_read_error |
; 16. Get the slot and pointer to the cache item, |
; change the status to not-modified copy of the disk |
; and go to 4c. |
pop ecx |
lea esi, [ecx*sizeof.CACHE_ITEM/4] |
shl esi, 2 |
add esi, [ebx+DISKCACHE.pointer] |
mov [esi+CACHE_ITEM.Status], CACHE_ITEM_COPY |
jmp .found_in_cache |
|
mov ecx, [.cache] |
lea eax, [edi*3] |
mov esi, [ecx+DISKCACHE.pointer] |
lea esi, [eax*4+esi] |
|
mov eax, [.sector_lo] |
mov edx, [.sector_hi] |
mov [esi], eax ; sector number |
mov [esi+4], edx ; sector number |
mov dword [esi+8], 1; hd read - mark as same as in hd |
|
.yeshdcache: |
|
mov esi, edi |
mov ecx, [.cache] |
shl esi, 9 |
add esi, [ecx+DISKCACHE.data] |
|
mov edi, ebx |
mov ecx, 512/4 |
rep movsd ; move data |
xor eax, eax ; successful read |
.read_done: |
mov ecx, [.cache] |
; On error at steps 13-15, release the lock |
; and pass the error to the caller. |
.floppy_read_error: |
pop ecx |
.floppy_cache_error: |
mov ecx, [ebp+PARTITION.Disk] |
add ecx, DISK.CacheLock |
push eax |
call mutex_unlock |
pop eax |
add esp, 12 |
pop edi esi edx ecx |
ret |
jmp .return_eax |
|
; This function is intended to replace the old 'hd_write' function when |
; [hdd_appl_data] = 0, so its input/output parameters are the same, except |
162,11 → 742,13 |
; eax is relative to partition start |
; out: eax = error code; 0 = ok |
fs_write32_sys: |
; Save ecx, set ecx to SysCache and let the common part do its work. |
push ecx |
mov ecx, [ebp+PARTITION.Disk] |
add ecx, DISK.SysCache |
jmp fs_write32_common |
; Just call the advanced function. |
push ecx edx |
xor edx, edx |
mov ecx, 1 |
call fs_write64_sys |
pop edx ecx |
ret |
|
; This function is intended to replace the old 'hd_write' function when |
; [hdd_appl_data] = 1, so its input/output parameters are the same, except |
175,144 → 757,89 |
; eax is relative to partition start |
; out: eax = error code; 0 = ok |
fs_write32_app: |
; Save ecx, set ecx to AppCache and let the common part do its work. |
push ecx |
mov ecx, [ebp+PARTITION.Disk] |
add ecx, DISK.AppCache |
|
; This label is the common part of fs_read32_sys and fs_read32_app. |
fs_write32_common: |
; 1. Check that the required sector is inside the partition. If no, return |
; DISK_STATUS_END_OF_MEDIA. |
cmp dword [ebp+PARTITION.Length+4], 0 |
jnz @f |
cmp dword [ebp+PARTITION.Length], eax |
ja @f |
mov eax, DISK_STATUS_END_OF_MEDIA |
pop ecx |
ret |
@@: |
push edx esi |
; 2. Get the absolute sector on the disk. |
; Just call the advanced function. |
push ecx edx |
xor edx, edx |
add eax, dword [ebp+PARTITION.FirstSector] |
adc edx, dword [ebp+PARTITION.FirstSector+4] |
; 3. If there is no cache for this disk, just pass request to the driver. |
cmp [ecx+DISKCACHE.pointer], 0 |
jnz .scancache |
push 1 |
push esp ; numsectors |
push edx ; startsector |
push eax ; startsector |
push ebx ; buffer |
mov esi, [ebp+PARTITION.Disk] |
mov al, DISKFUNC.write |
call disk_call_driver |
pop ecx |
pop esi edx |
pop ecx |
mov ecx, 1 |
call fs_write64_app |
pop edx ecx |
ret |
.scancache: |
; 4. Scan the cache. |
push edi ecx ; scan cache |
push edx eax |
virtual at esp |
.sector_lo dd ? |
.sector_hi dd ? |
.cache dd ? |
end virtual |
; The following code is inherited from hd_write. The differences are: |
; all code is protected by the cache lock; |
; sector is 64-bit, not 32-bit. |
call mutex_lock |
|
; check if the cache already has the sector and overwrite it |
mov eax, [.sector_lo] |
mov edx, [.sector_hi] |
mov esi, [ecx+DISKCACHE.pointer] |
mov ecx, [ecx+DISKCACHE.sad_size] |
add esi, 12 |
; Lookup for the given sector in the given cache. |
; If the sector is not present, return error. |
; The caller must acquire the cache lock. |
; in: edx:eax = sector |
; in: ebx -> DISKCACHE structure |
; out: CF set if sector is not in cache |
; out: ecx = index in cache |
; out: esi -> sector:status |
proc cache_lookup_read |
mov esi, [ebx+DISKCACHE.pointer] |
add esi, sizeof.CACHE_ITEM |
|
mov edi, 1 |
mov ecx, 1 |
|
.hdwritecache: |
cmp dword [esi+8], 0 ; if cache slot is empty |
je .not_in_cache_write |
.hdreadcache: |
|
cmp [esi], eax ; if the slot has the sector |
jne .not_in_cache_write |
cmp [esi+4], edx ; if the slot has the sector |
je .yes_in_cache_write |
cmp [esi+CACHE_ITEM.Status], CACHE_ITEM_EMPTY |
je .nohdcache |
|
.not_in_cache_write: |
cmp [esi+CACHE_ITEM.SectorLo], eax |
jne .nohdcache |
cmp [esi+CACHE_ITEM.SectorHi], edx |
jne .nohdcache |
clc |
ret |
|
add esi, 12 |
inc edi |
dec ecx |
jnz .hdwritecache |
.nohdcache: |
|
; sector not found in cache |
; write the block to a new location |
|
mov esi, [.cache] |
call find_empty_slot64 ; ret in edi |
test eax, eax |
jne .hd_write_access_denied |
|
mov ecx, [.cache] |
lea eax, [edi*3] |
mov esi, [ecx+DISKCACHE.pointer] |
lea esi, [eax*4+esi] |
|
mov eax, [.sector_lo] |
mov edx, [.sector_hi] |
mov [esi], eax ; sector number |
mov [esi+4], edx ; sector number |
|
.yes_in_cache_write: |
|
mov dword [esi+8], 2 ; write - differs from hd |
|
shl edi, 9 |
mov ecx, [.cache] |
add edi, [ecx+DISKCACHE.data] |
|
mov esi, ebx |
mov ecx, 512/4 |
rep movsd ; move data |
xor eax, eax ; success |
.hd_write_access_denied: |
mov ecx, [.cache] |
push eax |
call mutex_unlock |
pop eax |
add esp, 12 |
pop edi esi edx ecx |
add esi, sizeof.CACHE_ITEM |
inc ecx |
cmp ecx, [ebx+DISKCACHE.sad_size] |
jbe .hdreadcache |
stc |
ret |
endp |
|
; This internal function is called from fs_read32_* and fs_write32_*. It is the |
; analogue of find_empty_slot for 64-bit sectors. |
find_empty_slot64: |
; Lookup for the given sector in the given cache. |
; If the sector is not present, allocate space for it, |
; possibly flushing data. |
; in: edx:eax = sector |
; in: ebx -> DISKCACHE structure |
; in: ebp -> PARTITION structure |
; out: eax = error code |
; out: ecx = index in cache |
; out: esi -> sector:status |
proc cache_lookup_write |
call cache_lookup_read |
jnc .return0 |
push edx eax |
;----------------------------------------------------------- |
; find empty or read slot, flush cache if next 12.5% is used by write |
; output : edi = cache slot |
; output : ecx = cache slot |
;----------------------------------------------------------- |
; Note: the code is essentially inherited, so probably |
; no analysis of efficiency were done. |
; However, it works. |
.search_again: |
mov ecx, [esi+DISKCACHE.sad_size] |
mov edi, [esi+DISKCACHE.search_start] |
shr ecx, 3 |
mov eax, [ebx+DISKCACHE.sad_size] |
mov ecx, [ebx+DISKCACHE.search_start] |
shr eax, 3 |
lea esi, [ecx*sizeof.CACHE_ITEM/4] |
shl esi, 2 |
add esi, [ebx+DISKCACHE.pointer] |
.search_for_empty: |
inc edi |
cmp edi, [esi+DISKCACHE.sad_size] |
inc ecx |
add esi, sizeof.CACHE_ITEM |
cmp ecx, [ebx+DISKCACHE.sad_size] |
jbe .inside_cache |
mov edi, 1 |
mov ecx, 1 |
mov esi, [ebx+DISKCACHE.pointer] |
add esi, sizeof.CACHE_ITEM |
.inside_cache: |
lea eax, [edi*3] |
shl eax, 2 |
add eax, [esi+DISKCACHE.pointer] |
cmp dword [eax+8], 2 |
cmp [esi+CACHE_ITEM.Status], CACHE_ITEM_MODIFIED |
jb .found_slot ; it's empty or read |
dec ecx |
dec eax |
jnz .search_for_empty |
stdcall write_cache64, [ebp+PARTITION.Disk] ; no empty slots found, write all |
test eax, eax |
319,125 → 846,324 |
jne .found_slot_access_denied |
jmp .search_again ; and start again |
.found_slot: |
mov [esi+DISKCACHE.search_start], edi |
mov [ebx+DISKCACHE.search_start], ecx |
popd [esi+CACHE_ITEM.SectorLo] |
popd [esi+CACHE_ITEM.SectorHi] |
.return0: |
xor eax, eax ; success |
ret |
.found_slot_access_denied: |
add esp, 8 |
ret |
endp |
|
; This function is intended to replace the old 'write_cache' function. |
proc write_cache64 uses ecx edx esi edi, disk:dword |
locals |
cache_chain_started dd 0 |
cache_chain_size dd ? |
cache_chain_pos dd ? |
cache_chain_ptr dd ? |
endl |
saved_esi_pos = 16+12 ; size of local variables + size of registers before esi |
; If there is no cache for this disk, nothing to do. |
cmp [esi+DISKCACHE.pointer], 0 |
jz .flush |
;----------------------------------------------------------- |
; write all changed sectors to disk |
;----------------------------------------------------------- |
|
; write difference ( 2 ) from cache to DISK |
mov ecx, [esi+DISKCACHE.sad_size] |
mov esi, [esi+DISKCACHE.pointer] |
add esi, 12 |
mov edi, 1 |
.write_cache_more: |
cmp dword [esi+8], 2 ; if cache slot is not different |
jne .write_chain |
mov dword [esi+8], 1 ; same as in hd |
mov eax, [esi] |
mov edx, [esi+4] ; edx:eax = sector to write |
; Объединяем запись цепочки последовательных секторов в одно обращение к диску |
cmp ecx, 1 |
jz .nonext |
cmp dword [esi+12+8], 2 |
jnz .nonext |
push eax edx |
; Flush the given cache. |
; The caller must acquire the cache lock. |
; in: ebx -> DISKCACHE |
; in: first argument in stdcall convention -> PARTITION |
proc write_cache64 |
; 1. Setup stack frame. |
push esi edi ; save used registers to be stdcall |
sub esp, .local_vars_size ; reserve space for local vars |
virtual at esp |
.local_vars: |
.cache_end dd ? ; item past the end of the cache |
.size_left dd ? ; items left to scan |
.current_ptr dd ? ; pointer to the current item |
; |
; Write operations are coalesced in chains, |
; one chain describes a sequential interval of sectors, |
; they can be sequential or scattered in the cache. |
.sequential dd ? |
; boolean variable, 1 if the current chain is sequential in the cache, |
; 0 if additional buffer is needed to perform the operation |
.chain_start_pos dd ? ; slot of chain start item |
.chain_start_ptr dd ? ; pointer to chain start item |
.chain_size dd ? ; chain size (thanks, C.O.) |
.iteration_size dd ? |
; If the chain size is too large, split the operation to several iterations. |
; This is size in sectors for one iterations. |
.iteration_buffer dd ? ; temporary buffer for non-sequential chains |
.local_vars_size = $ - .local_vars |
rd 2 ; saved registers |
dd ? ; return address |
.disk dd ? ; first argument |
end virtual |
; 1. If there is no cache for this disk, nothing to do, just return zero. |
cmp [ebx+DISKCACHE.pointer], 0 |
jz .return0 |
; 2. Prepare for the loop: initialize current pointer and .size_left, |
; calculate .cache_end. |
mov ecx, [ebx+DISKCACHE.sad_size] |
mov [.size_left], ecx |
lea ecx, [ecx*sizeof.CACHE_ITEM/4] |
shl ecx, 2 |
mov esi, [ebx+DISKCACHE.pointer] |
add esi, sizeof.CACHE_ITEM |
add ecx, esi |
mov [.cache_end], ecx |
; 3. Main loop: go over all items, go to 5 for every modified item. |
.look: |
cmp [esi+CACHE_ITEM.Status], CACHE_ITEM_MODIFIED |
jz .begin_write |
.look_next: |
add esi, sizeof.CACHE_ITEM |
dec [.size_left] |
jnz .look |
; 4. Return success. |
.return0: |
xor eax, eax |
.return: |
add esp, .local_vars_size |
pop edi esi ; restore used registers to be stdcall |
ret 4 ; return popping one argument |
.begin_write: |
; We have found a modified item. |
; 5. Prepare for chain finding: save the current item, initialize chain variables. |
mov [.current_ptr], esi |
; Initialize chain as sequential zero-length starting at the current item. |
mov [.chain_start_ptr], esi |
mov eax, [ebx+DISKCACHE.sad_size] |
sub eax, [.size_left] |
inc eax |
mov [.chain_start_pos], eax |
mov [.chain_size], 0 |
mov [.sequential], 1 |
; 6. Expand the chain backward. |
; Note: the main loop in step 2 looks for items sequentially, |
; so the previous item is not modified. If the previous sector |
; is present in the cache, it automatically makes the chain scattered. |
; 6a. Calculate sector number: one before the sector for the current item. |
mov eax, [esi+CACHE_ITEM.SectorLo] |
mov edx, [esi+CACHE_ITEM.SectorHi] |
sub eax, 1 |
sbb edx, 0 |
.find_chain_start: |
; 6b. For each sector where the previous item does not expand the chain, |
; call the lookup function without adding to the cache. |
call cache_lookup_read |
; 6c. If the sector is not found in cache or is not modified, stop expanding |
; and advance to step 7. |
jc .found_chain_start |
cmp [esi+CACHE_ITEM.Status], CACHE_ITEM_MODIFIED |
jnz .found_chain_start |
; 6d. We have found a new block that expands the chain backwards. |
; It makes the chain non-sequential. |
; Normally, sectors come in sequential blocks, so try to look at previous items |
; before returning to 6b; if there is a sequential block indeed, this saves some |
; time instead of many full-fledged lookups. |
mov [.sequential], 0 |
mov [.chain_start_pos], ecx |
.look_backward: |
; 6e. For each sector, update chain start pos/ptr, decrement sector number, |
; look at the previous item. |
mov [.chain_start_ptr], esi |
inc [.chain_size] |
sub eax, 1 |
sbb edx, 0 |
sub esi, sizeof.CACHE_ITEM |
; If the previous item exists... |
cmp esi, [ebx+DISKCACHE.pointer] |
jbe .find_chain_start |
; ...describes the correct sector... |
cmp [esi+CACHE_ITEM.SectorLo], eax |
jnz .find_chain_start |
cmp [esi+CACHE_ITEM.SectorHi], edx |
jnz .find_chain_start |
; ...and is modified... |
cmp [esi+CACHE_ITEM.Status], CACHE_ITEM_MODIFIED |
jnz .found_chain_start |
; ...expand the chain one sector backwards and continue the loop at 6e. |
; Otherwise, advance to step 7 if the previous item describes the correct sector |
; but is not modified, and return to step 6b otherwise. |
dec [.chain_start_pos] |
jmp .look_backward |
.found_chain_start: |
; 7. Expand the chain forward. |
; 7a. Prepare for the loop at 7b: |
; set esi = pointer to current item, edx:eax = current sector. |
mov esi, [.current_ptr] |
mov eax, [esi+CACHE_ITEM.SectorLo] |
mov edx, [esi+CACHE_ITEM.SectorHi] |
.look_forward: |
; 7b. First, look at the next item. If it describes the next sector: |
; if it is modified, expand the chain with that sector and continue this step, |
; if it is not modified, the chain is completed, so advance to step 8. |
inc [.chain_size] |
add eax, 1 |
adc edx, 0 |
cmp eax, [esi+12] |
jnz @f |
cmp edx, [esi+12+4] |
add esi, sizeof.CACHE_ITEM |
cmp esi, [.cache_end] |
jae .find_chain_end |
cmp [esi+CACHE_ITEM.SectorLo], eax |
jnz .find_chain_end |
cmp [esi+CACHE_ITEM.SectorHi], edx |
jnz .find_chain_end |
cmp [esi+CACHE_ITEM.Status], CACHE_ITEM_MODIFIED |
jnz .found_chain_end |
jmp .look_forward |
.find_chain_end: |
; 7c. Otherwise, call the lookup function. |
call cache_lookup_read |
; 7d. If the next sector is present in the cache and is modified, |
; mark the chain as non-sequential and continue to step 7b. |
jc .found_chain_end |
cmp [esi+CACHE_ITEM.Status], CACHE_ITEM_MODIFIED |
jnz .found_chain_end |
mov [.sequential], 0 |
jmp .look_forward |
.found_chain_end: |
; 8. Decide whether the chain is sequential or scattered. |
; Advance to step 9 for sequential chains, go to step 10 for scattered chains. |
cmp [.sequential], 0 |
jz .write_non_sequential |
.write_sequential: |
; 9. Write a sequential chain to disk. |
; 9a. Pass the entire chain to the driver. |
mov eax, [.chain_start_ptr] |
mov edx, [.chain_start_pos] |
shl edx, 9 |
add edx, [ebx+DISKCACHE.data] |
lea ecx, [.chain_size] |
push ecx ; numsectors |
pushd [eax+CACHE_ITEM.SectorHi] ; startsector |
pushd [eax+CACHE_ITEM.SectorLo] ; startsector |
push edx ; buffer |
mov esi, [ebp+PARTITION.Disk] |
mov al, DISKFUNC.write |
call disk_call_driver |
; 9b. If failed, pass the error code to the driver. |
test eax, eax |
jnz .return |
; 9c. If succeeded, mark all sectors in the chain as not-modified, |
; advance current item and number of items left to skip the chain. |
mov esi, [.current_ptr] |
mov eax, [.chain_size] |
sub [.size_left], eax |
@@: |
pop edx eax |
jnz .nonext |
cmp [cache_chain_started], 1 |
jz @f |
mov [cache_chain_started], 1 |
mov [cache_chain_size], 0 |
mov [cache_chain_pos], edi |
mov [cache_chain_ptr], esi |
mov [esi+CACHE_ITEM.Status], CACHE_ITEM_COPY |
add esi, sizeof.CACHE_ITEM |
dec eax |
jnz @b |
; 9d. Continue the main loop at step 2 if there are more sectors. |
; Return success otherwise. |
cmp [.size_left], 0 |
jnz .look |
jmp .return0 |
.write_non_sequential: |
; Write a non-sequential chain to the disk. |
; 10. Allocate a temporary buffer. |
; Use [.chain_size] sectors, but |
; not greater than CACHE_MAX_ALLOC_SIZE bytes |
; and not greater than half of free memory. |
mov eax, [pg_data.pages_free] |
shr eax, 1 |
jz .nomemory |
cmp eax, CACHE_MAX_ALLOC_SIZE shr 12 |
jbe @f |
mov eax, CACHE_MAX_ALLOC_SIZE shr 12 |
@@: |
inc [cache_chain_size] |
cmp [cache_chain_size], 16 |
jnz .continue |
jmp .write_chain |
.nonext: |
call .flush_cache_chain |
shl eax, 12 - 9 |
cmp eax, [.chain_size] |
jbe @f |
mov eax, [.chain_size] |
@@: |
mov [.iteration_size], eax |
shl eax, 9 |
stdcall kernel_alloc, eax |
test eax, eax |
jnz .nothing |
mov [cache_chain_size], 1 |
mov [cache_chain_ptr], esi |
call .write_cache_sector |
test eax, eax |
jnz .nothing |
jmp .continue |
.write_chain: |
call .flush_cache_chain |
test eax, eax |
jnz .nothing |
.continue: |
add esi, 12 |
inc edi |
dec ecx |
jnz .write_cache_more |
call .flush_cache_chain |
test eax, eax |
jnz .nothing |
.flush: |
mov esi, [disk] |
mov al, DISKFUNC.flush |
call disk_call_driver |
.nothing: |
ret |
|
.flush_cache_chain: |
xor eax, eax |
cmp [cache_chain_started], eax |
jz @f |
call .write_cache_chain |
mov [cache_chain_started], 0 |
jz .nomemory |
mov [.iteration_buffer], eax |
.write_non_sequential_iteration: |
; 11. Split the chain so that each iteration fits in the allocated buffer. |
; Iteration size is the minimum of chain size and allocated size. |
mov eax, [.chain_size] |
cmp eax, [.iteration_size] |
jae @f |
mov [.iteration_size], eax |
@@: |
retn |
|
.write_cache_sector: |
mov [cache_chain_size], 1 |
mov [cache_chain_pos], edi |
.write_cache_chain: |
pusha |
mov edi, [cache_chain_pos] |
mov ecx, [ebp-saved_esi_pos] |
shl edi, 9 |
add edi, [ecx+DISKCACHE.data] |
mov ecx, [cache_chain_size] |
push ecx |
; 12. Prepare arguments for the driver. |
mov esi, [.chain_start_ptr] |
mov edi, [.iteration_buffer] |
push [.iteration_size] |
push esp ; numsectors |
mov eax, [cache_chain_ptr] |
pushd [eax+4] |
pushd [eax] ; startsector |
push [esi+CACHE_ITEM.SectorHi] ; startsector |
push [esi+CACHE_ITEM.SectorLo] ; startsector |
push edi ; buffer |
mov esi, [ebp] |
mov esi, [esi+PARTITION.Disk] |
; 13. Copy data from the cache to the temporary buffer, |
; advancing chain_start pos/ptr and marking sectors as not-modified. |
; 13a. Prepare for the loop: push number of sectors to process. |
push [.iteration_size+20] ; temporary variable |
.copy_loop: |
; 13b. For each sector, copy the data. |
; Note that edi is advanced automatically. |
mov esi, [.chain_start_pos+24] |
shl esi, 9 |
add esi, [ebx+DISKCACHE.data] |
mov ecx, 512/4 |
rep movsd |
; 13c. Mark the item as not-modified. |
mov esi, [.chain_start_ptr+24] |
mov [esi+CACHE_ITEM.Status], CACHE_ITEM_COPY |
; 13d. Check whether the next sector continues the chain. |
; If so, advance to 13e. Otherwise, go to 13f. |
mov eax, [esi+CACHE_ITEM.SectorLo] |
mov edx, [esi+CACHE_ITEM.SectorHi] |
add esi, sizeof.CACHE_ITEM |
add eax, 1 |
adc edx, 0 |
cmp esi, [.cache_end+24] |
jae .no_forward |
cmp [esi+CACHE_ITEM.SectorLo], eax |
jnz .no_forward |
cmp [esi+CACHE_ITEM.SectorHi], edx |
jnz .no_forward |
; 13e. Increment position/pointer to the chain and |
; continue the loop. |
inc [.chain_start_pos+24] |
mov [.chain_start_ptr+24], esi |
dec dword [esp] |
jnz .copy_loop |
jmp .copy_done |
.no_forward: |
; 13f. Call the lookup function without adding to the cache. |
; Update position/pointer with returned value. |
; Note: for the last sector in the chain, ecx/esi may contain |
; garbage; we are not going to use them in this case. |
call cache_lookup_read |
mov [.chain_start_pos+24], ecx |
mov [.chain_start_ptr+24], esi |
dec dword [esp] |
jnz .copy_loop |
.copy_done: |
; 13g. Restore the stack after 13a. |
pop ecx |
; 14. Call the driver. |
mov esi, [ebp+PARTITION.Disk] |
mov al, DISKFUNC.write |
call disk_call_driver |
pop ecx |
mov [esp+28], eax |
popa |
retn |
pop ecx ; numsectors |
; 15. If the driver has returned an error, free the buffer allocated at step 10 |
; and pass the error to the caller. |
; Otherwise, remove the processed part from the chain and continue iterations |
; starting in step 11 if there are more data to process. |
test eax, eax |
jnz .nonsequential_error |
sub [.chain_size], ecx |
jnz .write_non_sequential_iteration |
; 16. The chain is written. Free the temporary buffer |
; and continue the loop at step 2. |
stdcall kernel_free, [.iteration_buffer] |
mov esi, [.current_ptr] |
jmp .look_next |
.nonsequential_error: |
push eax |
stdcall kernel_free, [.iteration_buffer+4] |
pop eax |
jmp .return |
.nomemory: |
mov eax, DISK_STATUS_NO_MEMORY |
jmp .return |
endp |
|
; This internal function is called from disk_add to initialize the caching for |
486,10 → 1212,8 |
@@: |
; 3. Fill two DISKCACHE structures. |
mov [esi+DISK.SysCache.pointer], eax |
lea ecx, [esi+DISK.SysCache.mutex] |
lea ecx, [esi+DISK.CacheLock] |
call mutex_init |
lea ecx, [esi+DISK.AppCache.mutex] |
call mutex_init |
; The following code is inherited from getcache.inc. |
mov edx, [esi+DISK.SysCache.pointer] |
and [esi+DISK.SysCache.search_start], 0 |
577,12 → 1301,21 |
; esi = pointer to DISK |
disk_sync: |
; The algorithm is straightforward. |
push esi |
cmp [esi+DISK.SysCache.pointer], 0 |
jz .nothing |
lea ecx, [esi+DISK.CacheLock] |
call mutex_lock |
push ebx |
push esi ; for second write_cache64 |
push esi ; for first write_cache64 |
add esi, DISK.SysCache |
lea ebx, [esi+DISK.SysCache] |
call write_cache64 |
add esi, DISK.AppCache - DISK.SysCache |
add ebx, DISK.AppCache - DISK.SysCache |
call write_cache64 |
pop esi |
pop ebx |
lea ecx, [esi+DISK.CacheLock] |
call mutex_unlock |
.nothing: |
mov al, DISKFUNC.flush |
call disk_call_driver |
ret |