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Implement the rest of the IO hook. We now do directly satisfy write requests

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by writing them into our buffers and directly satisfy read requests by copying
our buffers, filling any gaps by spawning off subrequests to the underlaying
filesystem.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@32900 a95241bf-73f2-0310-859d-f6bbb57e9c96
This commit is contained in:
Michael Lotz 2009-09-02 03:09:28 +00:00
parent 7e26ad5af7
commit 44fbca2790
2 changed files with 79 additions and 24 deletions
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1
src/add-ons/kernel/file_systems/layers/write_overlay/Jamfile
View File

@ -1,6 +1,7 @@
SubDir HAIKU_TOP src add-ons kernel file_systems layers write_overlay ;
UsePrivateKernelHeaders ;
SubDirHdrs $(HAIKU_TOP) src system kernel device_manager ;
KernelAddon write_overlay :
write_overlay.cpp

98
src/add-ons/kernel/file_systems/layers/write_overlay/write_overlay.cpp
View File

@ -23,6 +23,8 @@
#include <KernelExport.h>
#include <NodeMonitor.h>
#include "IORequest.h"
//#define TRACE_OVERLAY
#ifdef TRACE_OVERLAY
@ -132,9 +134,14 @@ public:
status_t Close(void *cookie);
status_t FreeCookie(void *cookie);
status_t Read(void *cookie, off_t position, void *buffer,
size_t *length, bool readPages);
size_t *length, bool readPages,
IORequest *ioRequest);
status_t Write(void *cookie, off_t position,
const void *buffer, size_t *length);
const void *buffer, size_t length,
IORequest *request);
status_t SynchronousIO(void *cookie, IORequest *request);
status_t SetFlags(void *cookie, int flags);
status_t CreateDir(const char *name, int perms);
@ -519,7 +526,7 @@ OverlayInode::FreeCookie(void *_cookie)
status_t
OverlayInode::Read(void *_cookie, off_t position, void *buffer, size_t *length,
bool readPages)
bool readPages, IORequest *ioRequest)
{
if (position >= fStat.st_size) {
*length = 0;
@ -555,6 +562,20 @@ OverlayInode::Read(void *_cookie, off_t position, void *buffer, size_t *length,
result = fSuperVnode.ops->read_pages(SuperVolume(),
&fSuperVnode, superCookie, position, &vector, 1,
&readLength);
} else if (ioRequest != NULL) {
IORequest *subRequest;
result = ioRequest->CreateSubRequest(position, position,
readLength, subRequest);
if (result != B_OK)
return result;
result = fSuperVnode.ops->io(SuperVolume(), &fSuperVnode,
superCookie, subRequest);
if (result != B_OK)
return result;
result = subRequest->Wait(0, 0);
readLength = subRequest->TransferredBytes();
} else {
result = fSuperVnode.ops->read(SuperVolume(), &fSuperVnode,
superCookie, position, pointer, &readLength);
@ -572,7 +593,11 @@ OverlayInode::Read(void *_cookie, off_t position, void *buffer, size_t *length,
if (gapSize > 0) {
// there's a gap before our next position which we cannot
// fill with original file content, zero it out
if (ioRequest != NULL)
;// TODO: handle this case
else
memset(pointer, 0, gapSize);
bytesLeft -= gapSize;
position += gapSize;
pointer += gapSize;
@ -585,8 +610,14 @@ OverlayInode::Read(void *_cookie, off_t position, void *buffer, size_t *length,
off_t elementEnd = element->position + element->length;
if (elementEnd > position) {
size_t copyLength = MIN(elementEnd - position, bytesLeft);
memcpy(pointer, element->buffer + (position - element->position),
const void *source = element->buffer + (position
- element->position);
if (ioRequest != NULL) {
ioRequest->CopyData(source, (addr_t)pointer - (addr_t)buffer,
copyLength);
} else
memcpy(pointer, source, copyLength);
bytesLeft -= copyLength;
position += copyLength;
@ -602,7 +633,7 @@ OverlayInode::Read(void *_cookie, off_t position, void *buffer, size_t *length,
status_t
OverlayInode::Write(void *_cookie, off_t position, const void *buffer,
size_t *length)
size_t length, IORequest *ioRequest)
{
if (_cookie != NULL) {
open_cookie *cookie = (open_cookie *)_cookie;
@ -618,7 +649,7 @@ OverlayInode::Write(void *_cookie, off_t position, const void *buffer,
write_buffer *other = fWriteBuffers;
write_buffer *swallow = NULL;
off_t newPosition = position;
size_t newLength = *length;
size_t newLength = length;
uint32 swallowCount = 0;
while (other) {
@ -643,8 +674,11 @@ OverlayInode::Write(void *_cookie, off_t position, const void *buffer,
if (other->position <= newPosition) {
if (swallowCount == 1 && otherEnd >= newEnd) {
// other chunk completely covers us, just copy
memcpy(other->buffer + (newPosition - other->position),
buffer, *length);
void *target = other->buffer + (newPosition - other->position);
if (ioRequest != NULL)
ioRequest->CopyData(0, target, length);
else
memcpy(target, buffer, length);
fStat.st_mtime = time(NULL);
notify_stat_changed(SuperVolume()->id, fInodeNumber,
@ -694,7 +728,11 @@ OverlayInode::Write(void *_cookie, off_t position, const void *buffer,
}
}
memcpy(element->buffer + (position - newPosition), buffer, *length);
void *target = element->buffer + (position - newPosition);
if (ioRequest != NULL)
ioRequest->CopyData(0, target, length);
else
memcpy(target, buffer, length);
fStat.st_mtime = time(NULL);
notify_stat_changed(SuperVolume()->id, fInodeNumber,
@ -703,6 +741,25 @@ OverlayInode::Write(void *_cookie, off_t position, const void *buffer,
}
status_t
OverlayInode::SynchronousIO(void *cookie, IORequest *request)
{
status_t result;
size_t length = request->Length();
if (request->IsWrite())
result = Write(cookie, request->Offset(), NULL, length, request);
else
result = Read(cookie, request->Offset(), NULL, &length, false, request);
if (result != B_OK)
return result;
request->SetTransferredBytes(false, length);
request->SetStatusAndNotify(B_OK);
return B_OK;
}
status_t
OverlayInode::SetFlags(void *_cookie, int flags)
{
@ -803,8 +860,7 @@ OverlayInode::CreateSymlink(const char *name, const char *path, int mode)
if (result != B_OK)
return result;
size_t writeLength = strlen(path);
return newNode->Write(NULL, 0, path, &writeLength);
return newNode->Write(NULL, 0, path, strlen(path), NULL);
}
@ -815,7 +871,7 @@ OverlayInode::ReadSymlink(char *buffer, size_t *bufferSize)
if (!S_ISLNK(fStat.st_mode))
return B_BAD_VALUE;
return Read(NULL, 0, buffer, bufferSize, false);
return Read(NULL, 0, buffer, bufferSize, false, NULL);
}
if (fSuperVnode.ops->read_symlink == NULL)
@ -1239,7 +1295,7 @@ overlay_read_pages(fs_volume *volume, fs_vnode *vnode, void *cookie, off_t pos,
for (size_t i = 0; i < count; i++) {
size_t transferBytes = MIN(vecs[i].iov_len, bytesLeft);
status_t result = node->Read(cookie, pos, vecs[i].iov_base,
&transferBytes, true);
&transferBytes, true, NULL);
if (result != B_OK) {
*numBytes -= bytesLeft;
return result;
@ -1272,7 +1328,7 @@ overlay_write_pages(fs_volume *volume, fs_vnode *vnode, void *cookie, off_t pos,
for (size_t i = 0; i < count; i++) {
size_t transferBytes = MIN(vecs[i].iov_len, bytesLeft);
status_t result = node->Write(cookie, pos, vecs[i].iov_base,
&transferBytes);
transferBytes, NULL);
if (result != B_OK) {
*numBytes -= bytesLeft;
return result;
@ -1299,17 +1355,15 @@ static status_t
overlay_io(fs_volume *volume, fs_vnode *vnode, void *cookie,
io_request *request)
{
if (io_request_is_write(request))
return B_UNSUPPORTED;
OverlayInode *node = (OverlayInode *)vnode->private_node;
if (node->IsModified())
return B_UNSUPPORTED;
if (io_request_is_write(request) || node->IsModified())
return node->SynchronousIO(cookie, (IORequest *)request);
TRACE("relaying op: io\n");
fs_vnode *superVnode = node->SuperVnode();
if (superVnode->ops->io != NULL) {
return superVnode->ops->io(volume->super_volume, superVnode, cookie,
return superVnode->ops->io(volume->super_volume, superVnode,
cookie != NULL ? ((open_cookie *)cookie)->super_cookie : NULL,
request);
}
@ -1521,7 +1575,7 @@ overlay_read(fs_volume *volume, fs_vnode *vnode, void *cookie, off_t pos,
{
TRACE("read\n");
return ((OverlayInode *)vnode->private_node)->Read(cookie, pos, buffer,
length, false);
length, false, NULL);
}
@ -1531,7 +1585,7 @@ overlay_write(fs_volume *volume, fs_vnode *vnode, void *cookie, off_t pos,
{
TRACE("write\n");
return ((OverlayInode *)vnode->private_node)->Write(cookie, pos, buffer,
length);
*length, NULL);
}