vfs: Block devices

2026-10-25 19:07:58 +01:00
parent c0767b4631
commit 9991c1ddcb
10 changed files with 1346 additions and 0 deletions
@@ -0,0 +1,78 @@
+// SPDX-License-Identifier: ISC
+
+#include <zinnia/alloc.h>
+#include <zinnia/atomic.h>
+#include <zinnia/blockdev.h>
+#include <stdint.h>
+
+struct partition {
+    struct blockdev blk;
+    struct blockdev* parent;
+    uint64_t start;
+};
+
+static _Atomic(uint32_t) next_minor;
+
+static errno_t partition_submit(struct blockdev* blk, struct bio* bio) {
+    struct partition* part = containerof(blk, struct partition, blk);
+    struct blockdev* parent = part->parent;
+
+    if (bio->op != BIO_FLUSH) {
+        if (bio->lba >= blk->lba_count) {
+            bio_complete(bio, bio->op == BIO_READ ? 0 : ENOSPC, 0);
+            return 0;
+        }
+        if (bio->op == BIO_WRITE && bio->num_lbas > blk->lba_count - bio->lba) {
+            bio_complete(bio, ENOSPC, 0);
+            return 0;
+        }
+        bio->lba += part->start;
+    }
+    return parent->ops->submit(parent, bio);
+}
+
+static errno_t partition_ioctl(
+    struct blockdev* blk,
+    struct vfs_file* file,
+    uintptr_t request,
+    uintptr_t arg,
+    uintptr_t* out
+) {
+    struct blockdev* parent = containerof(blk, struct partition, blk)->parent;
+    if (!parent->ops->ioctl)
+        return ENOTTY;
+    return parent->ops->ioctl(parent, file, request, arg, out);
+}
+
+static void partition_destroy(struct blockdev* blk) {
+    struct partition* part = containerof(blk, struct partition, blk);
+    blockdev_unref(part->parent);
+    mem_free(part);
+}
+
+static const struct blockdev_ops partition_ops = {
+    .submit = partition_submit,
+    .ioctl = partition_ioctl,
+    .destroy = partition_destroy,
+};
+
+errno_t partition_new(struct blockdev* parent, uint64_t start_lba, uint64_t lba_count, struct blockdev** out) {
+    struct partition* part = mem_alloc(sizeof(struct partition), 0);
+    if (!part)
+        return ENOMEM;
+
+    blockdev_init(
+        &part->blk,
+        &partition_ops,
+        259,
+        atomic_fetch_add(&next_minor, 1, ATOMIC_RELAXED),
+        parent->lba_size,
+        lba_count
+    );
+    part->blk.limits = parent->limits;
+    blockdev_ref(parent);
+    part->parent = parent;
+    part->start = start_lba;
+    *out = &part->blk;
+    return 0;
+}