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vfs: support for uncached read/write

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Matheus
2024-05-26 15:31:26 -03:00
parent 171fde1574
commit 61fa847b65
6 changed files with 79 additions and 33 deletions
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kernel-src/fs/vfs.c
+41 -6
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@@ -154,9 +154,24 @@ static void bytestopages(uintmax_t offset, size_t size, uintmax_t *pageoffset, s
*pagecount = toppage - *pageoffset;
}
static int writenocache(vnode_t *node, page_t *page, uintmax_t pageoffset) {
// don't keep the pages in the cache!
// if its a file, do the proper filesystem sync.
// if its a block device, sync only the page we just dirtied
int e;
if (node->type == V_TYPE_REGULAR)
e = VOP_SYNC(node);
else
e = vmmcache_syncvnode(node, pageoffset, PAGE_SIZE);
// try to turn it into anonymous memory
vmmcache_evict(page);
return e;
}
int vfs_write(vnode_t *node, void *buffer, size_t size, uintmax_t offset, size_t *written, int flags) {
int err;
// TODO skip caching flag, cred check
if (node->type == V_TYPE_REGULAR || node->type == V_TYPE_BLKDEV) {
*written = 0;
// can't write a size 0 buffer
@@ -211,10 +226,16 @@ int vfs_write(vnode_t *node, void *buffer, size_t size, uintmax_t offset, size_t
void *address = MAKE_HHDM(pmm_getpageaddress(page));
memcpy((void *)((uintptr_t)address + startoffset), buffer, writesize);
vmmcache_makedirty(page);
pmm_release(FROM_HHDM(address));
*written += writesize;
pageoffset += 1;
pagecount -= 1;
if (flags & V_FFLAGS_NOCACHE) {
err = writenocache(node, page, pageoffset * PAGE_SIZE);
if (err)
goto leave;
}
pmm_release(FROM_HHDM(address));
}
for (uintmax_t offset = 0; offset < pagecount * PAGE_SIZE; offset += PAGE_SIZE) {
@@ -227,8 +248,14 @@ int vfs_write(vnode_t *node, void *buffer, size_t size, uintmax_t offset, size_t
void *address = MAKE_HHDM(pmm_getpageaddress(page));
memcpy(address, (void *)((uintptr_t)buffer + *written), writesize);
vmmcache_makedirty(page);
pmm_release(FROM_HHDM(address));
*written += writesize;
if (flags & V_FFLAGS_NOCACHE) {
err = writenocache(node, page, pageoffset * PAGE_SIZE + offset);
if (err)
goto leave;
}
pmm_release(FROM_HHDM(address));
}
leave:
@@ -242,7 +269,6 @@ int vfs_write(vnode_t *node, void *buffer, size_t size, uintmax_t offset, size_t
}
int vfs_read(vnode_t *node, void *buffer, size_t size, uintmax_t offset, size_t *bytesread, int flags) {
// TODO skip caching flag, cred check
int err;
if (node->type == V_TYPE_REGULAR || node->type == V_TYPE_BLKDEV) {
*bytesread = 0;
@@ -294,10 +320,15 @@ int vfs_read(vnode_t *node, void *buffer, size_t size, uintmax_t offset, size_t
size_t readsize = min(PAGE_SIZE - startoffset, size);
void *address = MAKE_HHDM(pmm_getpageaddress(page));
memcpy(buffer, (void *)((uintptr_t)address + startoffset), readsize);
pmm_release(FROM_HHDM(address));
*bytesread += readsize;
pageoffset += 1;
pagecount -= 1;
if (flags & V_FFLAGS_NOCACHE) {
// try to turn it into anonymous memory
vmmcache_evict(page);
}
pmm_release(FROM_HHDM(address));
}
for (uintmax_t offset = 0; offset < pagecount * PAGE_SIZE; offset += PAGE_SIZE) {
@@ -309,8 +340,12 @@ int vfs_read(vnode_t *node, void *buffer, size_t size, uintmax_t offset, size_t
size_t readsize = min(PAGE_SIZE, size - *bytesread);
void *address = MAKE_HHDM(pmm_getpageaddress(page));
memcpy((void *)((uintptr_t)buffer + *bytesread), address, readsize);
pmm_release(FROM_HHDM(address));
*bytesread += readsize;
if (flags & V_FFLAGS_NOCACHE) {
// try to turn it into anonymous memory
vmmcache_evict(page);
}
pmm_release(FROM_HHDM(address));
}
leave: