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syscalls: fsync

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Matheus
2024-05-25 12:04:29 -03:00
parent abb2fb9b26
commit b9071fe59e
11 changed files with 131 additions and 38 deletions
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kernel-src/mm/vmmcache.c
+65 -13
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@@ -232,12 +232,73 @@ int vmmcache_truncate(vnode_t *vnode, uintmax_t offset) {
return 0;
}
int vmmcache_syncvnode(vnode_t *vnode) {
__assert(!"unimplemented");
// called with lock held
// returns with lock released
static int syncpage(page_t *page) {
__assert(page->flags & PAGE_FLAGS_DIRTY);
page->flags &= ~PAGE_FLAGS_DIRTY;
RELEASE_LOCK();
int e = 0;
if ((page->flags & PAGE_FLAGS_TRUNCATED) == 0) {
e = VOP_PUTPAGE(page->backing, page->offset, (page_t *)page);
VOP_RELEASE(page->backing);
}
pmm_release(pmm_getpageaddress((page_t *)page));
return e;
}
static page_t *dirtylist;
int vmmcache_syncvnode(vnode_t *vnode, uintmax_t offset, size_t size) {
offset = ROUND_DOWN(offset, PAGE_SIZE);
uintmax_t top = offset + size;
// overflow check
__assert(top > offset);
HOLD_LOCK();
// loop through all vnode pages in memory and check which ones are in the range and are dirty
// TODO create a proper vnode dirty list as to not have to loop through the ENTIRE thing in memory
page_t *page = vnode->pages;
page_t *vnodedirtylist = NULL;
for (; page; page = page->vnodenext) {
if (page->offset < offset || page->offset >= top)
continue;
// remove from write list and add to an internal list using the write pointers
// in a singly linked list way
if (page->writenext)
page->writenext->writeprev = page->writeprev;
if (page->writeprev)
page->writeprev->writenext = page->writenext;
else
dirtylist = page->writenext;
page->writenext = vnodedirtylist;
page->writeprev = NULL;
vnodedirtylist = page;
}
RELEASE_LOCK();
int e = 0;
while (vnodedirtylist) {
// in the case of failure, only the first error to occur will be reported and we will not
// retry the write and keep on syncing the pages to disk
HOLD_LOCK();
page_t *page = vnodedirtylist;
vnodedirtylist = vnodedirtylist->writenext;
page->writenext = NULL;
int error = syncpage(page);
if (e == 0)
e = error;
// syncpage returns with lock released
}
return e;
}
int vmmcache_sync() {
polldesc_t polldesc = {0};
int e = poll_initdesc(&polldesc, 1);
@@ -313,22 +374,13 @@ static void writer() {
continue;
}
__assert(page->flags & PAGE_FLAGS_DIRTY);
page->flags &= ~PAGE_FLAGS_DIRTY;
dirtylist = page->writenext;
if (dirtylist)
dirtylist->writeprev = NULL;
page->writenext = NULL;
RELEASE_LOCK();
if ((page->flags & PAGE_FLAGS_TRUNCATED) == 0) {
VOP_PUTPAGE(page->backing, page->offset, (page_t *)page);
VOP_RELEASE(page->backing);
}
pmm_release(pmm_getpageaddress((page_t *)page));
// TODO notify error on vmmcache_syncvnode
syncpage((page_t *)page);
}
}