| 47,11 → 47,16 |
|---|
| #include <futex.h> |
| #include <as.h> |
| #include <libadt/list.h> |
| #include <assert.h> |
| #include "vfs.h" |
| |
| atomic_t fs_head_futex = FUTEX_INITIALIZER; |
| link_t fs_head; |
| |
| atomic_t fs_handle_next = { |
| .count = 1 |
| }; |
| |
| /** Verify the VFS info structure. |
| * |
| * @param info Info structure to be verified. |
| 305,13 → 310,80 |
|---|
| |
| /* |
| * That was it. The FS has been registered. |
| * In reply to the VFS_REGISTER request, we assign the client file |
| * system a global file system handle. |
| */ |
| ipc_answer_fast(rid, EOK, 0, 0); |
| dprintf("\"%s\" filesystem successfully registered.\n", |
| fs_info->vfs_info.name); |
| fs_info->fs_handle = (int) atomic_postinc(&fs_handle_next); |
| ipc_answer_fast(rid, EOK, (ipcarg_t) fs_info->fs_handle, 0); |
| dprintf("\"%s\" filesystem successfully registered, handle=%d.\n", |
| fs_info->vfs_info.name, fs_info->fs_handle); |
| |
| } |
| |
| /** For a given file system handle, implement policy for allocating a phone. |
| * |
| * @param handle File system handle. |
| * |
| * @return Phone over which a multi-call request can be safely |
| * sent. Return 0 if no phone was found. |
| */ |
| int vfs_grab_phone(int handle) |
| { |
| /* |
| * For now, we don't try to be very clever and very fast. |
| * We simply lookup the phone in the fs_head list. We currently don't |
| * open any additional phones (even though that itself would be pretty |
| * straightforward; housekeeping multiple open phones to a FS task would |
| * be more demanding). Instead, we simply take the respective |
| * phone_futex and keep it until vfs_release_phone(). |
| */ |
| futex_down(&fs_head_futex); |
| link_t *cur; |
| fs_info_t *fs; |
| for (cur = fs_head.next; cur != &fs_head; cur = cur->next) { |
| fs = list_get_instance(cur, fs_info_t, fs_link); |
| if (fs->fs_handle == handle) { |
| futex_up(&fs_head_futex); |
| /* |
| * For now, take the futex unconditionally. |
| * Oh yeah, serialization rocks. |
| * It will be up'ed in vfs_release_phone(). |
| */ |
| futex_down(&fs->phone_futex); |
| return fs->phone; |
| } |
| } |
| futex_up(&fs_head_futex); |
| return 0; |
| } |
| |
| /** Tell VFS that the phone is in use for any request. |
| * |
| * @param phone Phone to FS task. |
| */ |
| void vfs_release_phone(int phone) |
| { |
| bool found = false; |
| |
| futex_down(&fs_head_futex); |
| link_t *cur; |
| for (cur = fs_head.next; cur != &fs_head; cur = cur->next) { |
| fs_info_t *fs = list_get_instance(cur, fs_info_t, fs_link); |
| if (fs->phone == phone) { |
| found = true; |
| futex_up(&fs_head_futex); |
| futex_up(&fs->phone_futex); |
| return; |
| } |
| } |
| futex_up(&fs_head_futex); |
| |
| /* |
| * Not good to get here. |
| */ |
| assert(found == true); |
| } |
| |
| /** |
| * @} |
| */ |