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* The file cache must clear partial pages as well, since they can be mapped

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directly via mmap().
* This fixes bug #4106.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@31669 a95241bf-73f2-0310-859d-f6bbb57e9c96
This commit is contained in:
Axel Dörfler 2009-07-21 10:17:57 +00:00
parent cf2a64ba52
commit db8fb4fdf0
1 changed files with 16 additions and 1 deletions
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17
src/system/kernel/cache/file_cache.cpp vendored
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@ -336,6 +336,7 @@ read_into_cache(file_cache_ref *ref, void *cookie, off_t offset,
uint32 vecCount = 0;
size_t numBytes = PAGE_ALIGN(pageOffset + bufferSize);
size_t bytesUntouched = numBytes;
vm_page *pages[MAX_IO_VECS];
ConditionVariable busyConditions[MAX_IO_VECS];
int32 pageIndex = 0;
@ -363,7 +364,7 @@ read_into_cache(file_cache_ref *ref, void *cookie, off_t offset,
// read file into reserved pages
status_t status = vfs_read_pages(ref->vnode, cookie, offset, vecs,
vecCount, B_PHYSICAL_IO_REQUEST, &numBytes);
if (status < B_OK) {
if (status != B_OK) {
// reading failed, free allocated pages
dprintf("file_cache: read pages failed: %s\n", strerror(status));
@ -379,6 +380,20 @@ read_into_cache(file_cache_ref *ref, void *cookie, off_t offset,
return status;
}
// Clear out any leftovers that were not touched by the above read - we're
// doing this here so that not every file system/device has to implement
// this
bytesUntouched -= numBytes;
for (int32 i = vecCount; i-- > 0 && bytesUntouched != 0; ) {
size_t length = min_c(bytesUntouched, vecs[i].iov_len);
addr_t address = (addr_t)vecs[i].iov_base + vecs[i].iov_len - length;
vm_memset_physical(address, 0, length);
bytesUntouched -= length;
}
// copy the pages if needed and unmap them again
for (int32 i = 0; i < pageIndex; i++) {