fix: separate any i/o to sequential device from caching layer

[lunaix-os.git] / lunaix-os / kernel / fs / vfs.c

diff --git a/lunaix-os/kernel/fs/vfs.c b/lunaix-os/kernel/fs/vfs.c
index 48ec27dc18d06155be990d6926f20b1da413f993..53d21d8b026baa7f07ce38bc34a12cda78c0ee90 100644 (file)
--- a/lunaix-os/kernel/fs/vfs.c
+++ b/lunaix-os/kernel/fs/vfs.c
@@ -39,6 +39,7 @@ static int fs_id = 0;
 
 struct hstr vfs_ddot = HSTR("..", 2);
 struct hstr vfs_dot = HSTR(".", 1);
 
 struct hstr vfs_ddot = HSTR("..", 2);
 struct hstr vfs_dot = HSTR(".", 1);

+struct hstr vfs_empty = HSTR("", 0);

 
 struct v_dnode*
 vfs_d_alloc();
 
 struct v_dnode*
 vfs_d_alloc();


@@ -71,6 +72,7 @@ vfs_init()
     // 创建一个根superblock，用来蕴含我们的根目录。
     root_sb = vfs_sb_alloc();
     root_sb->root = vfs_d_alloc();
     // 创建一个根superblock，用来蕴含我们的根目录。
     root_sb = vfs_sb_alloc();
     root_sb->root = vfs_d_alloc();

+    root_sb->root->inode = vfs_i_alloc();

 }
 
 inline struct hbucket*
 }
 
 inline struct hbucket*


@@ -86,9 +88,13 @@ __dcache_get_bucket(struct v_dnode* parent, unsigned int hash)
 struct v_dnode*
 vfs_dcache_lookup(struct v_dnode* parent, struct hstr* str)
 {
 struct v_dnode*
 vfs_dcache_lookup(struct v_dnode* parent, struct hstr* str)
 {

-    if (!str->len)
+    if (!str->len || HSTR_EQ(str, &vfs_dot))

         return parent;
 
         return parent;
 

+    if (HSTR_EQ(str, &vfs_ddot)) {
+        return parent->parent ? parent->parent : parent;
+    }
+

     struct hbucket* slot = __dcache_get_bucket(parent, str->hash);
 
     struct v_dnode *pos, *n;
     struct hbucket* slot = __dcache_get_bucket(parent, str->hash);
 
     struct v_dnode *pos, *n;


@@ -109,11 +115,11 @@ vfs_dcache_add(struct v_dnode* parent, struct v_dnode* dnode)
 }
 
 int
 }
 
 int

-vfs_walk(struct v_dnode* start,
-         const char* path,
-         struct v_dnode** dentry,
-         struct hstr* component,
-         int walk_options)
+__vfs_walk(struct v_dnode* start,
+           const char* path,
+           struct v_dnode** dentry,
+           struct hstr* component,
+           int walk_options)

 {
     int errno = 0;
     int i = 0, j = 0;
 {
     int errno = 0;
     int i = 0, j = 0;


@@ -141,7 +147,7 @@ vfs_walk(struct v_dnode* start,
                 return ENAMETOOLONG;
             }
             if (!VFS_VALID_CHAR(current)) {
                 return ENAMETOOLONG;
             }
             if (!VFS_VALID_CHAR(current)) {

-                return VFS_EINVLD;
+                return EINVAL;

             }
             name_content[j++] = current;
             if (lookahead) {
             }
             name_content[j++] = current;
             if (lookahead) {


@@ -171,8 +177,7 @@ vfs_walk(struct v_dnode* start,
 
         if (!dnode) {
             dnode = vfs_d_alloc();
 
         if (!dnode) {
             dnode = vfs_d_alloc();

-            dnode->name = HSTR(valloc(VFS_NAME_MAXLEN), j);
-            dnode->name.hash = name.hash;
+            dnode->name = HHSTR(valloc(VFS_NAME_MAXLEN), j, name.hash);

 
             strcpy(dnode->name.value, name_content);
 
 
             strcpy(dnode->name.value, name_content);
 


@@ -214,6 +219,44 @@ error:
     return errno;
 }
 
     return errno;
 }
 

+#define VFS_MAX_SYMLINK 16
+
+int
+vfs_walk(struct v_dnode* start,
+         const char* path,
+         struct v_dnode** dentry,
+         struct hstr* component,
+         int options)
+{
+    struct v_dnode* interim;
+    char* pathname = path;
+    int errno = __vfs_walk(start, path, &interim, component, options);
+    int counter = 0;
+
+    while (!errno) {
+        if (counter >= VFS_MAX_SYMLINK) {
+            errno = ELOOP;
+            continue;
+        }
+        if ((interim->inode->itype & VFS_IFSYMLINK) &&
+            !(options & VFS_WALK_NOFOLLOW) &&
+            interim->inode->ops.read_symlink) {
+            errno = interim->inode->ops.read_symlink(interim->inode, &pathname);
+            if (errno) {
+                break;
+            }
+        } else {
+            break;
+        }
+        errno = __vfs_walk(start, pathname, &interim, component, options);
+        counter++;
+    }
+
+    *dentry = errno ? 0 : interim;
+
+    return errno;
+}
+

 int
 vfs_mount(const char* target, const char* fs_name, bdev_t device)
 {
 int
 vfs_mount(const char* target, const char* fs_name, bdev_t device)
 {


@@ -245,7 +288,7 @@ vfs_mount_at(const char* fs_name, bdev_t device, struct v_dnode* mnt_point)
 {
     struct filesystem* fs = fsm_get(fs_name);
     if (!fs)
 {
     struct filesystem* fs = fsm_get(fs_name);
     if (!fs)

-        return VFS_ENOFS;
+        return ENODEV;

     struct v_superblock* sb = vfs_sb_alloc();
     sb->dev = device;
     sb->fs_id = fs_id++;
     struct v_superblock* sb = vfs_sb_alloc();
     sb->dev = device;
     sb->fs_id = fs_id++;


@@ -267,7 +310,7 @@ vfs_unmount_at(struct v_dnode* mnt_point)
     int errno = 0;
     struct v_superblock* sb = mnt_point->super_block;
     if (!sb) {
     int errno = 0;
     struct v_superblock* sb = mnt_point->super_block;
     if (!sb) {

-        return VFS_EBADMNT;
+        return EINVAL;

     }
     if (!(errno = sb->fs->unmount(sb))) {
         struct v_dnode* fs_root = sb->root;
     }
     if (!(errno = sb->fs->unmount(sb))) {
         struct v_dnode* fs_root = sb->root;


@@ -285,10 +328,23 @@ vfs_open(struct v_dnode* dnode, struct v_file** file)
         return ENOTSUP;
     }
 
         return ENOTSUP;
     }
 

+    struct v_inode* inode = dnode->inode;

     struct v_file* vfile = cake_grab(file_pile);
     memset(vfile, 0, sizeof(*vfile));
 
     struct v_file* vfile = cake_grab(file_pile);
     memset(vfile, 0, sizeof(*vfile));
 

-    int errno = dnode->inode->ops.open(dnode->inode, vfile);
+    vfile->dnode = dnode;
+    vfile->inode = inode;
+    vfile->ref_count = 1;
+    vfile->ops = inode->default_fops;
+    inode->open_count++;
+
+    if ((inode->itype & VFS_IFFILE) && !inode->pg_cache) {
+        struct pcache* pcache = vzalloc(sizeof(struct pcache));
+        pcache_init(pcache);
+        inode->pg_cache = pcache;
+    }
+
+    int errno = inode->ops.open(inode, vfile);

     if (errno) {
         cake_release(file_pile, vfile);
     } else {
     if (errno) {
         cake_release(file_pile, vfile);
     } else {


@@ -298,14 +354,30 @@ vfs_open(struct v_dnode* dnode, struct v_file** file)
 }
 
 int
 }
 
 int

-vfs_close(struct v_file* file)
+vfs_link(struct v_dnode* to_link, struct v_dnode* name)

 {
 {

-    if (!file->ops.close) {
-        return ENOTSUP;
+    int errno;
+    if (to_link->super_block->root != name->super_block->root) {
+        errno = EXDEV;
+    } else if (!to_link->inode->ops.link) {
+        errno = ENOTSUP;
+    } else if (!(errno = to_link->inode->ops.link(to_link->inode, name))) {
+        name->inode = to_link->inode;
+        to_link->inode->link_count++;

     }
 
     }
 

-    int errno = file->ops.close(file);
-    if (!errno) {
+    return errno;
+}
+
+int
+vfs_close(struct v_file* file)
+{
+    int errno = 0;
+    if (!file->ops.close || !(errno = file->ops.close(file))) {
+        if (file->inode->open_count) {
+            file->inode->open_count--;
+        }
+        pcache_commit_all(file);

         cake_release(file_pile, file);
     }
     return errno;
         cake_release(file_pile, file);
     }
     return errno;


@@ -315,6 +387,7 @@ int
 vfs_fsync(struct v_file* file)
 {
     int errno = ENOTSUP;
 vfs_fsync(struct v_file* file)
 {
     int errno = ENOTSUP;

+    pcache_commit_all(file);

     if (file->ops.sync) {
         errno = file->ops.sync(file);
     }
     if (file->ops.sync) {
         errno = file->ops.sync(file);
     }


@@ -357,6 +430,7 @@ vfs_d_alloc()
     struct v_dnode* dnode = cake_grab(dnode_pile);
     memset(dnode, 0, sizeof(*dnode));
     llist_init_head(&dnode->children);
     struct v_dnode* dnode = cake_grab(dnode_pile);
     memset(dnode, 0, sizeof(*dnode));
     llist_init_head(&dnode->children);

+    dnode->name = vfs_empty;

     return dnode;
 }
 
     return dnode;
 }
 


@@ -374,7 +448,6 @@ vfs_i_alloc()
 {
     struct v_inode* inode = cake_grab(inode_pile);
     memset(inode, 0, sizeof(*inode));
 {
     struct v_inode* inode = cake_grab(inode_pile);
     memset(inode, 0, sizeof(*inode));

-

     return inode;
 }
 
     return inode;
 }
 


@@ -384,69 +457,115 @@ vfs_i_free(struct v_inode* inode)
     cake_release(inode_pile, inode);
 }
 
     cake_release(inode_pile, inode);
 }
 

+/* ---- System call definition and support ---- */
+
+#define FLOCATE_CREATE_EMPTY 1
+
+#define DO_STATUS(errno) SYSCALL_ESTATUS(__current->k_status = errno)
+#define DO_STATUS_OR_RETURN(errno) ({ errno < 0 ? DO_STATUS(errno) : errno; })
+

 int
 int

-__vfs_do_open(struct v_file** file_out, const char* path, int options)
+__vfs_try_locate_file(const char* path,
+                      struct v_dnode** fdir,
+                      struct v_dnode** file,
+                      int options)

 {
     char name_str[VFS_NAME_MAXLEN];
     struct hstr name = HSTR(name_str, 0);
 {
     char name_str[VFS_NAME_MAXLEN];
     struct hstr name = HSTR(name_str, 0);

-    struct v_dnode *dentry, *file;

     int errno;
     int errno;

-    if ((errno = vfs_walk(NULL, path, &dentry, &name, VFS_WALK_PARENT))) {
-        return ENOENT;
+    if ((errno = vfs_walk(NULL, path, fdir, &name, VFS_WALK_PARENT))) {
+        return errno;

     }
 
     }
 

-    vfs_walk(dentry, name.value, &file, NULL, 0);
+    errno = vfs_walk(*fdir, name.value, file, NULL, 0);
+    if (errno != ENOENT || !(options & FLOCATE_CREATE_EMPTY)) {
+        return errno;
+    }

 
 

-    struct v_file* opened_file = 0;
-    if (!file) {
-        if ((options & FO_CREATE)) {
-            errno = dentry->inode->ops.create(dentry->inode, opened_file);
-        } else {
-            errno = ENOENT;
-        }
-    } else {
-        errno = vfs_open(file, &opened_file);
+    if (!(errno = (*fdir)->inode->ops.create((*fdir)->inode))) {
+        struct v_dnode* file_new;
+        file_new = vfs_d_alloc();
+        file_new->name = HHSTR(valloc(VFS_NAME_MAXLEN), name.len, name.hash);
+        strcpy(file_new->name.value, name_str);
+        *file = file_new;
+
+        llist_append(&(*fdir)->children, &file_new->siblings);

     }
 
     }
 

-    *file_out = opened_file;

     return errno;
 }
 
     return errno;
 }
 

-__DEFINE_LXSYSCALL2(int, open, const char*, path, int, options)
+int
+__file_cached_read(struct v_file* file, void* buf, size_t len, size_t fpos)
+{
+    return pcache_read(file, buf, len, fpos);
+}
+
+int
+vfs_do_open(const char* path, int options)

 {
 {

-    struct v_file* opened_file;
-    int errno = __vfs_do_open(&opened_file, path, options), fd;
+    int errno, fd;
+    struct v_dnode *dentry, *file;
+    struct v_file* ofile = 0;

 
 

-    __current->k_status = errno;
+    errno = __vfs_try_locate_file(path, &dentry, &file, 0);
+
+    if (errno != ENOENT && (options & FO_CREATE)) {
+        errno = dentry->inode->ops.create(dentry->inode);
+    }
+
+    if (!errno && (errno = vfs_open(file, &ofile))) {
+        return errno;
+    }
+
+    struct v_inode* o_inode = ofile->inode;
+    if (!(o_inode->itype & VFS_IFSEQDEV) && !(options & FO_DIRECT)) {
+        // XXX Change here accordingly when signature of pcache_r/w changed.
+        ofile->ops.read = pcache_read;
+        ofile->ops.write = pcache_write;
+    }

 
     if (!errno && !(errno = vfs_alloc_fdslot(&fd))) {
         struct v_fd* fd_s = vzalloc(sizeof(*fd_s));
 
     if (!errno && !(errno = vfs_alloc_fdslot(&fd))) {
         struct v_fd* fd_s = vzalloc(sizeof(*fd_s));

-        fd_s->file = opened_file;
-        fd_s->pos = opened_file->inode->fsize & -((options & FO_APPEND) != 0);
+        ofile->f_pos = ofile->inode->fsize & -((options & FO_APPEND) != 0);
+        fd_s->file = ofile;
+        fd_s->flags = options;

         __current->fdtable->fds[fd] = fd_s;
         return fd;
     }
 
         __current->fdtable->fds[fd] = fd_s;
         return fd;
     }
 

-    return SYSCALL_ESTATUS(errno);
+    return errno;
+}
+
+__DEFINE_LXSYSCALL2(int, open, const char*, path, int, options)
+{
+    int errno = vfs_do_open(path, options);
+    return DO_STATUS_OR_RETURN(errno);

 }
 
 }
 

-#define GET_FD(fd, fd_s)                                                       \
-    (fd >= 0 && fd < VFS_MAX_FD && (fd_s = __current->fdtable->fds[fd]))
+#define TEST_FD(fd) (fd >= 0 && fd < VFS_MAX_FD)
+#define GET_FD(fd, fd_s) (TEST_FD(fd) && (fd_s = __current->fdtable->fds[fd]))

 
 __DEFINE_LXSYSCALL1(int, close, int, fd)
 {
     struct v_fd* fd_s;
 
 __DEFINE_LXSYSCALL1(int, close, int, fd)
 {
     struct v_fd* fd_s;

-    int errno;
+    int errno = 0;

     if (!GET_FD(fd, fd_s)) {
         errno = EBADF;
     if (!GET_FD(fd, fd_s)) {
         errno = EBADF;

-    } else if (!(errno = vfs_close(fd_s->file))) {
-        vfree(fd_s);
-        __current->fdtable->fds[fd] = 0;
+        goto done_err;

     }
 
     }
 

-    __current->k_status = errno;
+    if (fd_s->file->ref_count > 1) {
+        fd_s->file->ref_count--;
+    } else if ((errno = vfs_close(fd_s->file))) {
+        goto done_err;
+    }
+
+    vfree(fd_s);
+    __current->fdtable->fds[fd] = 0;

 
 

-    return SYSCALL_ESTATUS(errno);
+done_err:
+    return DO_STATUS(errno);

 }
 
 void
 }
 
 void


@@ -467,7 +586,7 @@ __DEFINE_LXSYSCALL2(int, readdir, int, fd, struct dirent*, dent)
     int errno;
     if (!GET_FD(fd, fd_s)) {
         errno = EBADF;
     int errno;
     if (!GET_FD(fd, fd_s)) {
         errno = EBADF;

-    } else if (!(fd_s->file->inode->itype & VFS_INODE_TYPE_DIR)) {
+    } else if (!(fd_s->file->inode->itype & VFS_IFDIR)) {

         errno = ENOTDIR;
     } else {
         struct dir_context dctx =
         errno = ENOTDIR;
     } else {
         struct dir_context dctx =


@@ -475,13 +594,22 @@ __DEFINE_LXSYSCALL2(int, readdir, int, fd, struct dirent*, dent)
                                 .index = dent->d_offset,
                                 .read_complete_callback =
                                   __vfs_readdir_callback };
                                 .index = dent->d_offset,
                                 .read_complete_callback =
                                   __vfs_readdir_callback };

-        if (!(errno = fd_s->file->ops.readdir(fd_s->file, &dctx))) {
-            dent->d_offset++;
+        if (dent->d_offset == 0) {
+            __vfs_readdir_callback(&dctx, vfs_dot.value, vfs_dot.len, 0);
+        } else if (dent->d_offset == 1) {
+            __vfs_readdir_callback(&dctx, vfs_ddot.value, vfs_ddot.len, 0);
+        } else {
+            dctx.index -= 2;
+            if ((errno = fd_s->file->ops.readdir(fd_s->file, &dctx))) {
+                goto done;
+            }

         }
         }

+        errno = 0;
+        dent->d_offset++;

     }
 
     }
 

-    __current->k_status = errno;
-    return SYSCALL_ESTATUS(errno);
+done:
+    return DO_STATUS(errno);

 }
 
 __DEFINE_LXSYSCALL1(int, mkdir, const char*, path)
 }
 
 __DEFINE_LXSYSCALL1(int, mkdir, const char*, path)


@@ -497,7 +625,7 @@ __DEFINE_LXSYSCALL1(int, mkdir, const char*, path)
         errno = ENOTSUP;
     } else if (!parent->inode->ops.mkdir) {
         errno = ENOTSUP;
         errno = ENOTSUP;
     } else if (!parent->inode->ops.mkdir) {
         errno = ENOTSUP;

-    } else if (!(parent->inode->itype & VFS_INODE_TYPE_DIR)) {
+    } else if (!(parent->inode->itype & VFS_IFDIR)) {

         errno = ENOTDIR;
     } else {
         dir = vfs_d_alloc();
         errno = ENOTDIR;
     } else {
         dir = vfs_d_alloc();


@@ -511,8 +639,7 @@ __DEFINE_LXSYSCALL1(int, mkdir, const char*, path)
     }
 
 done:
     }
 
 done:

-    __current->k_status = errno;
-    return SYSCALL_ESTATUS(errno);
+    return DO_STATUS(errno);

 }
 
 __DEFINE_LXSYSCALL3(int, read, int, fd, void*, buf, size_t, count)
 }
 
 __DEFINE_LXSYSCALL3(int, read, int, fd, void*, buf, size_t, count)


@@ -521,16 +648,24 @@ __DEFINE_LXSYSCALL3(int, read, int, fd, void*, buf, size_t, count)
     struct v_fd* fd_s;
     if (!GET_FD(fd, fd_s)) {
         errno = EBADF;
     struct v_fd* fd_s;
     if (!GET_FD(fd, fd_s)) {
         errno = EBADF;

-    } else {
-        struct v_file* file = fd_s->file;
-        file->f_pos = fd_s->pos;
-        if ((errno = file->ops.read(file, buf, count)) >= 0) {
-            fd_s->pos += errno;
-        }
+        goto done;
+    }
+
+    struct v_file* file = fd_s->file;
+    if ((file->inode->itype & VFS_IFDIR)) {
+        errno = EISDIR;
+        goto done;

     }
 
     }
 

-    __current->k_status = errno;
-    return SYSCALL_ESTATUS(errno);
+    errno = file->ops.read(file, buf, count, file->f_pos);
+
+    if (errno > 0) {
+        file->f_pos += errno;
+        return errno;
+    }
+
+done:
+    return DO_STATUS(errno);

 }
 
 __DEFINE_LXSYSCALL3(int, write, int, fd, void*, buf, size_t, count)
 }
 
 __DEFINE_LXSYSCALL3(int, write, int, fd, void*, buf, size_t, count)


@@ -539,16 +674,24 @@ __DEFINE_LXSYSCALL3(int, write, int, fd, void*, buf, size_t, count)
     struct v_fd* fd_s;
     if (!GET_FD(fd, fd_s)) {
         errno = EBADF;
     struct v_fd* fd_s;
     if (!GET_FD(fd, fd_s)) {
         errno = EBADF;

-    } else {
-        struct v_file* file = fd_s->file;
-        file->f_pos = fd_s->pos;
-        if ((errno = file->ops.write(file, buf, count)) >= 0) {
-            fd_s->pos += errno;
-        }
+        goto done;

     }
 
     }
 

-    __current->k_status = errno;
-    return SYSCALL_ESTATUS(errno);
+    struct v_file* file = fd_s->file;
+    if ((file->inode->itype & VFS_IFDIR)) {
+        errno = EISDIR;
+        goto done;
+    }
+
+    errno = file->ops.write(file, buf, count, file->f_pos);
+
+    if (errno > 0) {
+        file->f_pos += errno;
+        return errno;
+    }
+
+done:
+    return DO_STATUS(errno);

 }
 
 __DEFINE_LXSYSCALL3(int, lseek, int, fd, int, offset, int, options)
 }
 
 __DEFINE_LXSYSCALL3(int, lseek, int, fd, int, offset, int, options)


@@ -558,24 +701,321 @@ __DEFINE_LXSYSCALL3(int, lseek, int, fd, int, offset, int, options)
     if (!GET_FD(fd, fd_s)) {
         errno = EBADF;
     } else {
     if (!GET_FD(fd, fd_s)) {
         errno = EBADF;
     } else {

-        size_t fpos = fd_s->file->f_pos;
+        struct v_file* file = fd_s->file;
+        size_t fpos = file->f_pos;

         switch (options) {
             case FSEEK_CUR:
         switch (options) {
             case FSEEK_CUR:

-                fpos = (size_t)((int)fd_s->file->f_pos + offset);
+                fpos = (size_t)((int)file->f_pos + offset);

                 break;
             case FSEEK_END:
                 break;
             case FSEEK_END:

-                fpos = (size_t)((int)fd_s->file->inode->fsize + offset);
+                fpos = (size_t)((int)file->inode->fsize + offset);

                 break;
             case FSEEK_SET:
                 fpos = offset;
                 break;
                 break;
             case FSEEK_SET:
                 fpos = offset;
                 break;

+        }
+        if (!file->ops.seek || !(errno = file->ops.seek(file, fpos))) {
+            file->f_pos = fpos;
+        }
+    }

 
 

-            default:
-                break;
+    return DO_STATUS(errno);
+}
+
+int
+vfs_get_path(struct v_dnode* dnode, char* buf, size_t size, int depth)
+{
+    if (!dnode) {
+        return 0;
+    }
+
+    if (depth > 64) {
+        return ELOOP;
+    }
+
+    size_t len = vfs_get_path(dnode->parent, buf, size, depth + 1);
+
+    if (len >= size) {
+        return len;
+    }
+
+    size_t cpy_size = MIN(dnode->name.len, size - len);
+    strncpy(buf + len, dnode->name.value, cpy_size);
+    len += cpy_size;
+
+    if (len < size) {
+        buf[len++] = PATH_DELIM;
+    }
+
+    return len;
+}
+
+int
+vfs_readlink(struct v_dnode* dnode, char* buf, size_t size)
+{
+    char* link;
+    if (dnode->inode->ops.read_symlink) {
+        int errno = dnode->inode->ops.read_symlink(dnode->inode, &link);
+        strncpy(buf, link, size);
+        return errno;
+    }
+    return 0;
+}
+
+__DEFINE_LXSYSCALL3(int, realpathat, int, fd, char*, buf, size_t, size)
+{
+    int errno;
+    struct v_fd* fd_s;
+    if (!GET_FD(fd, fd_s)) {
+        errno = EBADF;
+    } else {
+        struct v_dnode* dnode;
+        errno = vfs_get_path(fd_s->file->dnode, buf, size, 0);
+    }
+
+    if (errno >= 0) {
+        return errno;
+    }
+
+    return DO_STATUS(errno);
+}
+
+__DEFINE_LXSYSCALL3(int, readlink, const char*, path, char*, buf, size_t, size)
+{
+    int errno;
+    struct v_dnode* dnode;
+    if (!(errno = vfs_walk(NULL, path, &dnode, NULL, VFS_WALK_NOFOLLOW))) {
+        errno = vfs_readlink(dnode, buf, size);
+    }
+
+    if (errno >= 0) {
+        return errno;
+    }
+
+    return DO_STATUS(errno);
+}
+
+__DEFINE_LXSYSCALL4(int,
+                    readlinkat,
+                    int,
+                    dirfd,
+                    const char*,
+                    pathname,
+                    char*,
+                    buf,
+                    size_t,
+                    size)
+{
+    int errno;
+    struct v_fd* fd_s;
+    if (!GET_FD(dirfd, fd_s)) {
+        errno = EBADF;
+    } else {
+        struct v_dnode* dnode;
+        if (!(errno = vfs_walk(fd_s->file->dnode,
+                               pathname,
+                               &dnode,
+                               NULL,
+                               VFS_WALK_NOFOLLOW))) {
+            errno = vfs_readlink(fd_s->file->dnode, buf, size);

         }
         }

-        fd_s->pos = fpos;

     }
 
     }
 

-    __current->k_status = errno;
-    return SYSCALL_ESTATUS(errno);
+    if (errno >= 0) {
+        return errno;
+    }
+
+    return DO_STATUS(errno);
+}
+
+__DEFINE_LXSYSCALL1(int, rmdir, const char*, pathname)
+{
+    int errno;
+    struct v_dnode* dnode;
+    if ((errno = vfs_walk(NULL, pathname, &dnode, NULL, 0))) {
+        goto done;
+    }
+    if ((dnode->super_block->fs->types & FSTYPE_ROFS)) {
+        errno = EROFS;
+        goto done;
+    }
+
+    if (dnode->inode->open_count) {
+        errno = EBUSY;
+        goto done;
+    }
+
+    if ((dnode->inode->itype & VFS_IFDIR)) {
+        errno = dnode->inode->ops.rmdir(dnode->inode);
+    } else {
+        errno = ENOTDIR;
+    }
+
+done:
+    return DO_STATUS(errno);
+}
+
+int
+__vfs_do_unlink(struct v_inode* inode)
+{
+    int errno;
+    if (inode->open_count) {
+        errno = EBUSY;
+    } else if (!(inode->itype & VFS_IFDIR)) {
+        // TODO handle symbolic link and type other than regular file
+        errno = inode->ops.unlink(inode);
+        if (!errno) {
+            inode->link_count--;
+        }
+    } else {
+        errno = EISDIR;
+    }
+
+    return errno;
+}
+
+__DEFINE_LXSYSCALL1(int, unlink, const char*, pathname)
+{
+    int errno;
+    struct v_dnode* dnode;
+    if ((errno = vfs_walk(NULL, pathname, &dnode, NULL, 0))) {
+        goto done;
+    }
+    if ((dnode->super_block->fs->types & FSTYPE_ROFS)) {
+        errno = EROFS;
+        goto done;
+    }
+
+    errno = __vfs_do_unlink(dnode->inode);
+
+done:
+    return DO_STATUS(errno);
+}
+
+__DEFINE_LXSYSCALL2(int, unlinkat, int, fd, const char*, pathname)
+{
+    int errno;
+    struct v_fd* fd_s;
+    if (!GET_FD(fd, fd_s)) {
+        errno = EBADF;
+    } else {
+        struct v_dnode* dnode;
+        if (!(errno = vfs_walk(fd_s->file->dnode, pathname, &dnode, NULL, 0))) {
+            errno = __vfs_do_unlink(dnode->inode);
+        }
+    }
+
+done:
+    return DO_STATUS(errno);
+}
+
+__DEFINE_LXSYSCALL2(int, link, const char*, oldpath, const char*, newpath)
+{
+    int errno;
+    struct v_dnode *dentry, *to_link, *name_dentry, *name_file;
+
+    errno = __vfs_try_locate_file(oldpath, &dentry, &to_link, 0);
+    if (!errno) {
+        errno = __vfs_try_locate_file(
+          newpath, &name_dentry, &name_file, FLOCATE_CREATE_EMPTY);
+        if (!errno) {
+            errno = EEXIST;
+        } else if (name_file) {
+            errno = vfs_link(to_link, name_file);
+        }
+    }
+    return DO_STATUS(errno);
+}
+
+__DEFINE_LXSYSCALL1(int, fsync, int, fildes)
+{
+    int errno;
+    struct v_fd* fd_s;
+    if (!GET_FD(fildes, fd_s)) {
+        errno = EBADF;
+    } else {
+        errno = vfs_fsync(fd_s->file);
+    }
+
+    return DO_STATUS(errno);
+}
+
+int
+__vfs_dup_fd(struct v_fd* old, struct v_fd** new)
+{
+    int errno = 0;
+    struct v_fd* copied = cake_grab(fd_pile);
+
+    memcpy(copied, old, sizeof(struct v_fd));
+    old->file->ref_count++;
+
+    return errno;
+}
+
+__DEFINE_LXSYSCALL2(int, dup2, int, oldfd, int, newfd)
+{
+    if (newfd == oldfd) {
+        return newfd;
+    }
+
+    int errno;
+    struct v_fd *oldfd_s, *newfd_s;
+    if (!GET_FD(oldfd, oldfd_s) || TEST_FD(newfd)) {
+        errno = EBADF;
+        goto done;
+    }
+    newfd_s = __current->fdtable->fds[newfd];
+    if (newfd_s && (errno = vfs_close(newfd_s))) {
+        goto done;
+    }
+
+    if (!(errno = __vfs_dup_fd(oldfd_s, &newfd_s))) {
+        __current->fdtable->fds[newfd] = newfd_s;
+        return newfd;
+    }
+
+done:
+    return DO_STATUS(errno);
+}
+
+__DEFINE_LXSYSCALL1(int, dup, int, oldfd)
+{
+    int errno, newfd;
+    struct v_fd *oldfd_s, *newfd_s;
+    if (!GET_FD(oldfd, oldfd_s)) {
+        errno = EBADF;
+    } else if (!(errno = vfs_alloc_fdslot(&newfd)) &&
+               !(errno = __vfs_dup_fd(oldfd_s, &newfd_s))) {
+        __current->fdtable->fds[newfd] = newfd_s;
+        return newfd;
+    }
+
+    return DO_STATUS(errno);
+}
+
+__DEFINE_LXSYSCALL2(int,
+                    symlink,
+                    const char*,
+                    pathname,
+                    const char*,
+                    link_target)
+{
+    int errno;
+    struct v_dnode* dnode;
+    if ((errno = vfs_walk(NULL, pathname, &dnode, NULL, 0))) {
+        goto done;
+    }
+    if ((dnode->super_block->fs->types & FSTYPE_ROFS)) {
+        errno = EROFS;
+        goto done;
+    }
+    if (!dnode->inode->ops.symlink) {
+        errno = ENOTSUP;
+        goto done;
+    }
+
+    errno = dnode->inode->ops.symlink(dnode->inode, link_target);
+
+done:
+    return DO_STATUS(errno);

 }
\ No newline at end of file
 }
\ No newline at end of file