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* Fix missing initialization of the entry size on SetSize() that'd cause some

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attribute writes to not be visible.
* Don't read past the current node size when emulating write support.
* Fix writing calculations so that writing actually works as intended.
* Actually follow the linked list when joining write_buffers instead of using
  the same pointer that becomes invalid after the first iteration.
* Small optimizations.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@29251 a95241bf-73f2-0310-859d-f6bbb57e9c96
This commit is contained in:
Michael Lotz 2009-02-19 20:03:05 +00:00
parent 49004dc730
commit a4041d8a6e
1 changed files with 25 additions and 17 deletions
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42
src/add-ons/kernel/file_systems/overlay/overlay.cpp
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@ -422,6 +422,11 @@ status_t
OverlayInode::Read(void *_cookie, off_t position, void *buffer, size_t *length)
{
if (fVolume->WriteSupport()) {
if (position >= fCurrentNodeLength) {
*length = 0;
return B_OK;
}
if (position < fOriginalNodeLength) {
open_cookie *cookie = (open_cookie *)_cookie;
size_t readLength = MIN(fOriginalNodeLength - position, *length);
@ -436,8 +441,11 @@ OverlayInode::Read(void *_cookie, off_t position, void *buffer, size_t *length)
*length = MIN(fCurrentNodeLength - position, *length);
off_t end = position + *length;
while (element) {
if (element->position > end)
break;
off_t elementEnd = element->position + element->length;
if (elementEnd > position && element->position < end) {
if (elementEnd > position) {
off_t copyPosition = MAX(position, element->position);
size_t copyLength = MIN(elementEnd - position, *length);
memcpy((uint8 *)buffer + (copyPosition - position),
@ -473,7 +481,7 @@ OverlayInode::Write(void *_cookie, off_t position, const void *buffer,
off_t newEnd = newPosition + newLength;
off_t otherEnd = other->position + other->length;
if (otherEnd < newPosition) {
// other completely before us
// other is completely before us
link = &other->next;
other = other->next;
continue;
@ -489,20 +497,21 @@ OverlayInode::Write(void *_cookie, off_t position, const void *buffer,
swallow = other;
if (other->position <= newPosition) {
// other chunk overlaps us or is adjacent
if (otherEnd < newEnd) {
// extend the chunk to completely overlap us
newPosition = other->position;
newLength = other->length + (newEnd - otherEnd);
} else {
// other chunk completely overlaps us already
if (swallowCount == 1 && otherEnd >= newEnd) {
// other chunk completely covers us, just copy
memcpy(other->buffer + (newPosition - other->position),
buffer, *length);
fModificationTime = time(NULL);
notify_stat_changed(SuperVolume()->id, fInodeNumber,
B_STAT_MODIFICATION_TIME);
return B_OK;
}
other = other->next;
continue;
newLength += newPosition - other->position;
newPosition = other->position;
}
// we overlap the other chunk - swallow it
if (otherEnd > newEnd)
newLength += otherEnd - newEnd;
@ -529,14 +538,12 @@ OverlayInode::Write(void *_cookie, off_t position, const void *buffer,
// populate the buffer with the existing chunks
if (swallowCount > 0) {
while (swallowCount-- > 0) {
off_t swallowEnd = swallow->position + swallow->length;
if (swallow->position < position || swallowEnd > newEnd) {
memcpy(element->buffer + (swallow->position - newPosition),
swallow->buffer, swallow->length);
}
memcpy(element->buffer + (swallow->position - newPosition),
swallow->buffer, swallow->length);
element->next = swallow->next;
free(swallow);
swallow = element->next;
}
}
@ -1148,6 +1155,7 @@ AttributeEntry::SetSize(size_t size)
}
memcpy(newData, fData, min_c(fEntry->size, size));
fEntry->size = size;
fAllocatedData = true;
fData = newData;
return B_OK;