+/**
+ * @file vfs.c
+ * @author Lunaixsky (zelong56@gmail.com)
+ * @brief Lunaix virtual file system - an abstraction layer for all file system.
+ * @version 0.1
+ * @date 2022-07-24
+ *
+ * @copyright Copyright (c) 2022
+ *
+ */
+
+// Welcome to The Mountain O'Shit! :)
+
+/*
+ TODO vfs & device todos checklist
+
+ It is overseen by Twilight Sparkle ;)
+
+ 1. Get inodes hooked into lru (CHECKED)
+ 2. Get dnodes hooked into lru (CHECKED)
+ 3. Get inodes properly hashed so they can be reused by underling fs (CHECKED)
+ 4. (lru) Add a callback function (or destructor) for eviction. (CHECKED)
+ [good idea] or a constructor/destructor pattern in cake allocator ?
+ 5. (mount) Figure out a way to identify a busy mount point before unmount
+ maybe a unified mount_point structure that maintain a referencing
+ counter on any dnodes within the subtree? Such a counter will only
+ increament if a file is opened or a dnode is being used as working
+ directory and decreamenting conversely. (CHECKED)
+ 6. (mount) Ability to track all mount points (including sub-mounts)
+ so we can be confident to clean up everything when we
+ unmount. (CHECKED)
+ 7. (mount) Figure out a way to acquire the device represented by a dnode.
+ so it can be used to mount. (e.g. we wish to get `struct device*`
+ out of the dnode at /dev/sda)
+ [tip] we should pay attention at twifs and add a private_data field
+ under struct v_dnode? (CHECKED)
+ 8. (mount) Then, we should refactor on mount/unmount mechanism. (CHECKED)
+ 9. (mount) (future) Ability to mount any thing? e.g. Linux can mount a disk
+ image file using a so called "loopback" pseudo device. Maybe
+ we can do similar thing in Lunaix? A block device emulation
+ above the regular file when we mount it on.
+ 10. (device) device number (dev_t) allocation
+ [good idea] <class>:<subclass>:<uniq_id> composition (CHECKED)
+*/
+
#include <klibc/string.h>
+#include <lunaix/foptions.h>
#include <lunaix/fs.h>
#include <lunaix/mm/cake.h>
+#include <lunaix/mm/page.h>
#include <lunaix/mm/valloc.h>
+#include <lunaix/process.h>
+#include <lunaix/spike.h>
+#include <lunaix/syscall.h>
+#include <lunaix/syscall_utils.h>
-#define PATH_DELIM '/'
-#define DNODE_HASHTABLE_BITS 10
-#define DNODE_HASHTABLE_SIZE (1 << DNODE_HASHTABLE_BITS)
-#define DNODE_HASH_MASK (DNODE_HASHTABLE_SIZE - 1)
-#define DNODE_HASHBITS (32 - DNODE_HASHTABLE_BITS)
+#include <lunaix/fs/twifs.h>
-#define VFS_ETOOLONG -1
-#define VFS_ENOFS -2
+#include <usr/lunaix/dirent_defs.h>
static struct cake_pile* dnode_pile;
static struct cake_pile* inode_pile;
+static struct cake_pile* file_pile;
static struct cake_pile* superblock_pile;
-static struct cake_pile* name_pile;
+static struct cake_pile* fd_pile;
-static struct v_superblock* root_sb;
+struct v_dnode* vfs_sysroot;
static struct hbucket* dnode_cache;
-static int fs_id = 0;
-
-struct v_dnode*
-__new_dnode();
+struct lru_zone *dnode_lru, *inode_lru;
-void
-__free_dnode(struct v_dnode* dnode);
+struct hstr vfs_ddot = HSTR("..", 2);
+struct hstr vfs_dot = HSTR(".", 1);
+struct hstr vfs_empty = HSTR("", 0);
struct v_superblock*
-__new_superblock();
+vfs_sb_alloc();
void
-__free_superblock(struct v_superblock* sb);
+vfs_sb_free(struct v_superblock* sb);
+
+static int
+__vfs_try_evict_dnode(struct lru_node* obj);
+
+static int
+__vfs_try_evict_inode(struct lru_node* obj);
void
vfs_init()
{
- // 为他们专门创建一个蛋糕堆，而不使用valloc，这样我们可以最小化内部碎片的产生
- dnode_pile = cake_new_pile("dnode", sizeof(struct v_dnode), 1, 0);
- inode_pile = cake_new_pile("inode", sizeof(struct v_inode), 1, 0);
- name_pile = cake_new_pile("dname", VFS_NAME_MAXLEN, 1, 0);
+ // 为他们专门创建一个蛋糕堆，而不使用valloc，这样我们可以最小化内碎片的产生
+ dnode_pile = cake_new_pile("dnode_cache", sizeof(struct v_dnode), 1, 0);
+ inode_pile = cake_new_pile("inode_cache", sizeof(struct v_inode), 1, 0);
+ file_pile = cake_new_pile("file_cache", sizeof(struct v_file), 1, 0);
+ fd_pile = cake_new_pile("fd_cache", sizeof(struct v_fd), 1, 0);
superblock_pile =
- cake_new_pile("superblock", sizeof(struct v_superblock), 1, 0);
+ cake_new_pile("sb_cache", sizeof(struct v_superblock), 1, 0);
+
+ dnode_cache = vzalloc(VFS_HASHTABLE_SIZE * sizeof(struct hbucket));
+
+ dnode_lru = lru_new_zone(__vfs_try_evict_dnode);
+ inode_lru = lru_new_zone(__vfs_try_evict_inode);
- dnode_cache = valloc(DNODE_HASHTABLE_SIZE * sizeof(struct hbucket));
+ hstr_rehash(&vfs_ddot, HSTR_FULL_HASH);
+ hstr_rehash(&vfs_dot, HSTR_FULL_HASH);
- // 挂载Lunaix的根文件系统，TwiFS！
- struct filesystem* rootfs = fsm_get("twifs");
- root_sb = __new_superblock();
- rootfs->mount(root_sb, NULL);
+ // 创建一个根dnode。
+ vfs_sysroot = vfs_d_alloc(NULL, &vfs_empty);
+ vfs_sysroot->parent = vfs_sysroot;
+ atomic_fetch_add(&vfs_sysroot->ref_count, 1);
}
-inline struct hbucket*
-__dcache_get_bucket(struct v_dnode* parent, unsigned int hash)
+static inline struct hbucket*
+__dcache_hash(struct v_dnode* parent, u32_t* hash)
{
- // 与parent的指针值做加法，来减小碰撞的可能性。
- hash += (uint32_t)parent;
+ u32_t _hash = *hash;
// 确保低位更加随机
- hash = hash ^ (hash >> DNODE_HASHBITS);
- return &dnode_cache[hash & DNODE_HASH_MASK];
+ _hash = _hash ^ (_hash >> VFS_HASHBITS);
+ // 与parent的指针值做加法，来减小碰撞的可能性。
+ _hash += (u32_t)parent;
+ *hash = _hash;
+ return &dnode_cache[_hash & VFS_HASH_MASK];
}
struct v_dnode*
vfs_dcache_lookup(struct v_dnode* parent, struct hstr* str)
{
- struct hbucket* slot = __dcache_get_bucket(parent, str->hash);
+ if (!str->len || HSTR_EQ(str, &vfs_dot))
+ return parent;
+
+ if (HSTR_EQ(str, &vfs_ddot)) {
+ return parent->parent;
+ }
+
+ u32_t hash = str->hash;
+ struct hbucket* slot = __dcache_hash(parent, &hash);
struct v_dnode *pos, *n;
hashtable_bucket_foreach(slot, pos, n, hash_list)
{
- if (pos->name.hash == str->hash) {
+ if (pos->name.hash == hash) {
return pos;
}
}
void
vfs_dcache_add(struct v_dnode* parent, struct v_dnode* dnode)
{
- struct hbucket* bucket = __dcache_get_bucket(parent, dnode->name.hash);
+ assert(parent);
+
+ atomic_fetch_add(&dnode->ref_count, 1);
+ dnode->parent = parent;
+ llist_append(&parent->children, &dnode->siblings);
+
+ struct hbucket* bucket = __dcache_hash(parent, &dnode->name.hash);
hlist_add(&bucket->head, &dnode->hash_list);
}
-int
-vfs_walk(struct v_dnode* start, const char* path, struct v_dnode** dentry)
+void
+vfs_dcache_remove(struct v_dnode* dnode)
{
- int errno = 0;
- int i = 0, j = 0;
+ assert(dnode);
+ assert(dnode->ref_count == 1);
- if (path[0] == PATH_DELIM) {
- start = start->super_block->root;
- i++;
- }
+ llist_delete(&dnode->siblings);
+ llist_delete(&dnode->aka_list);
+ hlist_delete(&dnode->hash_list);
- struct v_dnode* dnode;
- struct v_dnode* current_level = start;
-
- char name_content[VFS_NAME_MAXLEN];
- struct hstr name = HSTR(name_content, 0);
-
- char current, lookahead;
- do {
- current = path[i++];
- lookahead = path[i++];
- if (current != PATH_DELIM) {
- if (j >= VFS_NAME_MAXLEN - 1) {
- errno = VFS_ETOOLONG;
- goto error;
- }
- name_content[j++] = current;
- if (lookahead) {
- continue;
- }
- }
+ dnode->parent = NULL;
+ atomic_fetch_sub(&dnode->ref_count, 1);
+}
+
+void
+vfs_dcache_rehash(struct v_dnode* new_parent, struct v_dnode* dnode)
+{
+ assert(new_parent);
+
+ hstr_rehash(&dnode->name, HSTR_FULL_HASH);
+ vfs_dcache_remove(dnode);
+ vfs_dcache_add(new_parent, dnode);
+}
- name_content[j] = 0;
- hstr_rehash(&name, 32);
+int
+vfs_open(struct v_dnode* dnode, struct v_file** file)
+{
+ if (!dnode->inode || !dnode->inode->ops->open) {
+ return ENOTSUP;
+ }
- dnode = vfs_dcache_lookup(current_level, &name);
+ struct v_inode* inode = dnode->inode;
- if (!dnode) {
- dnode = __new_dnode();
- strcpy(dnode->name.value, name_content);
- dnode->name.hash = name.hash;
- dnode->name.len = j;
+ lock_inode(inode);
- if ((errno =
- dnode->inode->ops.dir_lookup(current_level->inode, dnode))) {
- goto error;
- }
+ struct v_file* vfile = cake_grab(file_pile);
+ memset(vfile, 0, sizeof(*vfile));
- vfs_dcache_add(current_level, dnode);
+ vfile->dnode = dnode;
+ vfile->inode = inode;
+ vfile->ref_count = ATOMIC_VAR_INIT(1);
+ vfile->ops = inode->default_fops;
- dnode->parent = current_level;
- llist_append(¤t_level->children, &dnode->siblings);
- }
+ if ((inode->itype & F_MFILE) && !inode->pg_cache) {
+ struct pcache* pcache = vzalloc(sizeof(struct pcache));
+ pcache_init(pcache);
+ pcache->master = inode;
+ inode->pg_cache = pcache;
+ }
- j = 0;
- current_level = dnode;
- } while (lookahead);
+ int errno = inode->ops->open(inode, vfile);
+ if (errno) {
+ cake_release(file_pile, vfile);
+ } else {
+ atomic_fetch_add(&dnode->ref_count, 1);
+ inode->open_count++;
+ mnt_mkbusy(dnode->mnt);
- *dentry = dnode;
- return 0;
+ *file = vfile;
+ }
+
+ unlock_inode(inode);
-error:
- __free_dnode(dnode);
return errno;
}
+void
+vfs_assign_inode(struct v_dnode* assign_to, struct v_inode* inode)
+{
+ if (assign_to->inode) {
+ llist_delete(&assign_to->aka_list);
+ assign_to->inode->link_count--;
+ }
+ llist_append(&inode->aka_dnodes, &assign_to->aka_list);
+ assign_to->inode = inode;
+ inode->link_count++;
+}
+
int
-vfs_mount(const char* fs_name, bdev_t device, struct v_dnode* mnt_point)
+vfs_link(struct v_dnode* to_link, struct v_dnode* name)
{
- struct filesystem* fs = fsm_get(fs_name);
- if (!fs)
- return VFS_ENOFS;
- struct v_superblock* sb = __new_superblock();
- sb->dev = device;
- sb->fs_id = fs_id++;
+ int errno;
- int errno = 0;
- if (!(errno = fs->mount(sb, mnt_point))) {
- sb->fs = fs;
- llist_append(&root_sb->sb_list, &sb->sb_list);
+ if ((errno = vfs_check_writable(to_link))) {
+ return errno;
}
+ lock_inode(to_link->inode);
+ 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))) {
+ vfs_assign_inode(name, to_link->inode);
+ }
+ unlock_inode(to_link->inode);
+
return errno;
}
int
-vfs_unmount(const int fs_id)
+vfs_pclose(struct v_file* file, pid_t pid)
{
int errno = 0;
- struct v_superblock *pos, *n;
- llist_for_each(pos, n, &root_sb->sb_list, sb_list)
- {
- if (pos->fs_id != fs_id) {
- continue;
- }
- if (!(errno = pos->fs->unmount(pos))) {
- llist_delete(&pos->sb_list);
- __free_superblock(pos);
+ if (file->ref_count > 1) {
+ atomic_fetch_sub(&file->ref_count, 1);
+ } else if (!(errno = file->ops->close(file))) {
+ atomic_fetch_sub(&file->dnode->ref_count, 1);
+ file->inode->open_count--;
+
+ /*
+ * Prevent dead lock.
+ * This happened when process is terminated while blocking on read.
+ * In that case, the process is still holding the inode lock and it
+ will never get released.
+ * The unlocking should also include ownership check.
+ *
+ * To see why, consider two process both open the same file both with
+ * fd=x.
+ * Process A: busy on reading x
+ * Process B: do nothing with x
+ * Assuming that, after a very short time, process B get terminated
+ * while process A is still busy in it's reading business. By this
+ * design, the inode lock of this file x is get released by B rather
+ * than A. And this will cause a probable race condition on A if other
+ * process is writing to this file later after B exit.
+ */
+ if (mutex_on_hold(&file->inode->lock)) {
+ mutex_unlock_for(&file->inode->lock, pid);
}
- break;
+ mnt_chillax(file->dnode->mnt);
+
+ pcache_commit_all(file->inode);
+ cake_release(file_pile, file);
+ }
+ return errno;
+}
+
+int
+vfs_close(struct v_file* file)
+{
+ return vfs_pclose(file, __current->pid);
+}
+
+void
+vfs_free_fd(struct v_fd* fd)
+{
+ cake_release(fd_pile, fd);
+}
+
+int
+vfs_fsync(struct v_file* file)
+{
+ int errno;
+ if ((errno = vfs_check_writable(file->dnode))) {
+ return errno;
+ }
+
+ lock_inode(file->inode);
+
+ pcache_commit_all(file->inode);
+
+ errno = ENOTSUP;
+ if (file->ops->sync) {
+ errno = file->ops->sync(file);
}
+
+ unlock_inode(file->inode);
+
return errno;
}
+int
+vfs_alloc_fdslot(int* fd)
+{
+ for (size_t i = 0; i < VFS_MAX_FD; i++) {
+ if (!__current->fdtable->fds[i]) {
+ *fd = i;
+ return 0;
+ }
+ }
+ return EMFILE;
+}
+
struct v_superblock*
-__new_superblock()
+vfs_sb_alloc()
{
struct v_superblock* sb = cake_grab(superblock_pile);
memset(sb, 0, sizeof(*sb));
llist_init_head(&sb->sb_list);
- sb->root = __new_dnode();
+ sb->i_cache = vzalloc(VFS_HASHTABLE_SIZE * sizeof(struct hbucket));
+ return sb;
}
void
-__free_superblock(struct v_superblock* sb)
+vfs_sb_free(struct v_superblock* sb)
{
- __free_dnode(sb->root);
+ vfree(sb->i_cache);
cake_release(superblock_pile, sb);
}
+static int
+__vfs_try_evict_dnode(struct lru_node* obj)
+{
+ struct v_dnode* dnode = container_of(obj, struct v_dnode, lru);
+
+ if (!dnode->ref_count) {
+ vfs_d_free(dnode);
+ return 1;
+ }
+ return 0;
+}
+
+static int
+__vfs_try_evict_inode(struct lru_node* obj)
+{
+ struct v_inode* inode = container_of(obj, struct v_inode, lru);
+
+ if (!inode->link_count && !inode->open_count) {
+ vfs_i_free(inode);
+ return 1;
+ }
+ return 0;
+}
+
struct v_dnode*
-__new_dnode()
+vfs_d_alloc(struct v_dnode* parent, struct hstr* name)
{
struct v_dnode* dnode = cake_grab(dnode_pile);
- dnode->inode = cake_grab(inode_pile);
- dnode->name.value = cake_grab(name_pile);
+ if (!dnode) {
+ lru_evict_half(dnode_lru);
+
+ if (!(dnode = cake_grab(dnode_pile))) {
+ return NULL;
+ }
+ }
+
+ memset(dnode, 0, sizeof(*dnode));
+ llist_init_head(&dnode->children);
+ llist_init_head(&dnode->siblings);
+ llist_init_head(&dnode->aka_list);
+ mutex_init(&dnode->lock);
+
+ dnode->ref_count = ATOMIC_VAR_INIT(0);
+ dnode->name = HHSTR(vzalloc(VFS_NAME_MAXLEN), 0, 0);
+
+ hstrcpy(&dnode->name, name);
+
+ if (parent) {
+ dnode->super_block = parent->super_block;
+ dnode->mnt = parent->mnt;
+ }
+
+ lru_use_one(dnode_lru, &dnode->lru);
+
+ return dnode;
}
void
-__free_dnode(struct v_dnode* dnode)
+vfs_d_free(struct v_dnode* dnode)
{
- cake_release(inode_pile, dnode->inode);
- cake_release(name_pile, dnode->name.value);
+ assert(dnode->ref_count == 1);
+
+ if (dnode->inode) {
+ assert(dnode->inode->link_count > 0);
+ dnode->inode->link_count--;
+ }
+
+ vfs_dcache_remove(dnode);
+ // Make sure the children de-referencing their parent.
+ // With lru presented, the eviction will be propagated over the entire
+ // detached subtree eventually
+ struct v_dnode *pos, *n;
+ llist_for_each(pos, n, &dnode->children, siblings)
+ {
+ vfs_dcache_remove(pos);
+ }
+
+ vfree((void*)dnode->name.value);
cake_release(dnode_pile, dnode);
+}
+
+struct v_inode*
+vfs_i_find(struct v_superblock* sb, u32_t i_id)
+{
+ struct hbucket* slot = &sb->i_cache[i_id & VFS_HASH_MASK];
+ struct v_inode *pos, *n;
+ hashtable_bucket_foreach(slot, pos, n, hash_list)
+ {
+ if (pos->id == i_id) {
+ lru_use_one(inode_lru, &pos->lru);
+ return pos;
+ }
+ }
+
+ return NULL;
+}
+
+void
+vfs_i_addhash(struct v_inode* inode)
+{
+ struct hbucket* slot = &inode->sb->i_cache[inode->id & VFS_HASH_MASK];
+
+ hlist_delete(&inode->hash_list);
+ hlist_add(&slot->head, &inode->hash_list);
+}
+
+struct v_inode*
+vfs_i_alloc(struct v_superblock* sb)
+{
+ assert(sb->ops.init_inode);
+
+ struct v_inode* inode;
+ if (!(inode = cake_grab(inode_pile))) {
+ lru_evict_half(inode_lru);
+ if (!(inode = cake_grab(inode_pile))) {
+ return NULL;
+ }
+ }
+
+ memset(inode, 0, sizeof(*inode));
+ mutex_init(&inode->lock);
+ llist_init_head(&inode->xattrs);
+ llist_init_head(&inode->aka_dnodes);
+
+ sb->ops.init_inode(sb, inode);
+
+ inode->sb = sb;
+ inode->ctime = clock_unixtime();
+ inode->atime = inode->ctime;
+ inode->mtime = inode->ctime;
+
+ lru_use_one(inode_lru, &inode->lru);
+ return inode;
+}
+
+void
+vfs_i_free(struct v_inode* inode)
+{
+ if (inode->pg_cache) {
+ pcache_release(inode->pg_cache);
+ vfree(inode->pg_cache);
+ }
+ // we don't need to sync inode.
+ // If an inode can be free, then it must be properly closed.
+ // Hence it must be synced already!
+ if (inode->destruct) {
+ inode->destruct(inode);
+ }
+ hlist_delete(&inode->hash_list);
+ cake_release(inode_pile, inode);
+}
+
+/* ---- System call definition and support ---- */
+
+#define FLOCATE_CREATE_EMPTY 1
+#define FLOCATE_CREATE_ONLY 2
+#define FLOCATE_NOFOLLOW 4
+
+int
+vfs_getfd(int fd, struct v_fd** fd_s)
+{
+ if (TEST_FD(fd) && (*fd_s = __current->fdtable->fds[fd])) {
+ return 0;
+ }
+ return EBADF;
+}
+
+int
+__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);
+ int errno, woption = 0;
+
+ if ((options & FLOCATE_NOFOLLOW)) {
+ woption |= VFS_WALK_NOFOLLOW;
+ }
+
+ name_str[0] = 0;
+ if ((errno = vfs_walk_proc(path, fdir, &name, woption | VFS_WALK_PARENT))) {
+ return errno;
+ }
+
+ errno = vfs_walk(*fdir, name.value, file, NULL, woption);
+
+ if (errno != ENOENT && (options & FLOCATE_CREATE_ONLY)) {
+ return EEXIST;
+ }
+
+ if (errno != ENOENT ||
+ !(options & (FLOCATE_CREATE_EMPTY | FLOCATE_CREATE_ONLY))) {
+ return errno;
+ }
+
+ struct v_dnode* parent = *fdir;
+ struct v_dnode* file_new = vfs_d_alloc(parent, &name);
+
+ if (!file_new) {
+ return ENOMEM;
+ }
+
+ lock_dnode(parent);
+
+ if (!(errno = parent->inode->ops->create(parent->inode, file_new))) {
+ vfs_dcache_add(parent, file_new);
+ *file = file_new;
+ } else {
+ vfs_d_free(file_new);
+ }
+
+ unlock_dnode(parent);
+
+ return errno;
+}
+
+int
+vfs_do_open(const char* path, int options)
+{
+ int errno, fd, loptions = 0;
+ struct v_dnode *dentry, *file;
+ struct v_file* ofile = NULL;
+
+ if ((options & FO_CREATE)) {
+ loptions |= FLOCATE_CREATE_EMPTY;
+ } else if ((options & FO_NOFOLLOW)) {
+ loptions |= FLOCATE_NOFOLLOW;
+ }
+
+ errno = __vfs_try_locate_file(path, &dentry, &file, loptions);
+
+ if (!errno && !(errno = vfs_alloc_fdslot(&fd))) {
+
+ if (errno || (errno = vfs_open(file, &ofile))) {
+ return errno;
+ }
+
+ struct v_fd* fd_s = cake_grab(fd_pile);
+ memset(fd_s, 0, sizeof(*fd_s));
+
+ 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;
+ }
+
+ 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_LXSYSCALL1(int, close, int, fd)
+{
+ struct v_fd* fd_s;
+ int errno = 0;
+ if ((errno = vfs_getfd(fd, &fd_s))) {
+ goto done_err;
+ }
+
+ if ((errno = vfs_close(fd_s->file))) {
+ goto done_err;
+ }
+
+ cake_release(fd_pile, fd_s);
+ __current->fdtable->fds[fd] = 0;
+
+done_err:
+ return DO_STATUS(errno);
+}
+
+void
+__vfs_readdir_callback(struct dir_context* dctx,
+ const char* name,
+ const int len,
+ const int dtype)
+{
+ struct lx_dirent* dent = (struct lx_dirent*)dctx->cb_data;
+ strncpy(dent->d_name, name, DIRENT_NAME_MAX_LEN);
+ dent->d_nlen = len;
+ dent->d_type = dtype;
+}
+
+__DEFINE_LXSYSCALL2(int, sys_readdir, int, fd, struct lx_dirent*, dent)
+{
+ struct v_fd* fd_s;
+ int errno;
+
+ if ((errno = vfs_getfd(fd, &fd_s))) {
+ goto done;
+ }
+
+ struct v_inode* inode = fd_s->file->inode;
+
+ lock_inode(inode);
+
+ if ((inode->itype & F_FILE)) {
+ errno = ENOTDIR;
+ } else {
+ struct dir_context dctx =
+ (struct dir_context){ .cb_data = dent,
+ .index = dent->d_offset,
+ .read_complete_callback =
+ __vfs_readdir_callback };
+ errno = 1;
+ if (dent->d_offset == 0) {
+ __vfs_readdir_callback(&dctx, vfs_dot.value, vfs_dot.len, DT_DIR);
+ } else if (dent->d_offset == 1) {
+ __vfs_readdir_callback(&dctx, vfs_ddot.value, vfs_ddot.len, DT_DIR);
+ } else {
+ dctx.index -= 2;
+ if ((errno = fd_s->file->ops->readdir(fd_s->file, &dctx)) != 1) {
+ unlock_inode(inode);
+ goto done;
+ }
+ }
+ dent->d_offset++;
+ }
+
+ unlock_inode(inode);
+
+done:
+ return DO_STATUS_OR_RETURN(errno);
+}
+
+__DEFINE_LXSYSCALL3(int, read, int, fd, void*, buf, size_t, count)
+{
+ int errno = 0;
+ struct v_fd* fd_s;
+ if ((errno = vfs_getfd(fd, &fd_s))) {
+ goto done;
+ }
+
+ struct v_file* file = fd_s->file;
+ if (!(file->inode->itype & F_FILE)) {
+ errno = EISDIR;
+ goto done;
+ }
+
+ lock_inode(file->inode);
+
+ file->inode->atime = clock_unixtime();
+
+ if ((file->inode->itype & VFS_IFSEQDEV) || (fd_s->flags & FO_DIRECT)) {
+ errno = file->ops->read(file->inode, buf, count, file->f_pos);
+ } else {
+ errno = pcache_read(file->inode, buf, count, file->f_pos);
+ }
+
+ if (errno > 0) {
+ file->f_pos += errno;
+ unlock_inode(file->inode);
+ return errno;
+ }
+
+ unlock_inode(file->inode);
+
+done:
+ return DO_STATUS(errno);
+}
+
+__DEFINE_LXSYSCALL3(int, write, int, fd, void*, buf, size_t, count)
+{
+ int errno = 0;
+ struct v_fd* fd_s;
+ if ((errno = vfs_getfd(fd, &fd_s))) {
+ goto done;
+ }
+
+ struct v_file* file = fd_s->file;
+
+ if ((errno = vfs_check_writable(file->dnode))) {
+ goto done;
+ }
+
+ if (!(file->inode->itype & F_FILE)) {
+ errno = EISDIR;
+ goto done;
+ }
+
+ lock_inode(file->inode);
+
+ file->inode->mtime = clock_unixtime();
+
+ if ((file->inode->itype & VFS_IFSEQDEV) || (fd_s->flags & FO_DIRECT)) {
+ errno = file->ops->write(file->inode, buf, count, file->f_pos);
+ } else {
+ errno = pcache_write(file->inode, buf, count, file->f_pos);
+ }
+
+ if (errno > 0) {
+ file->f_pos += errno;
+ unlock_inode(file->inode);
+ return errno;
+ }
+
+ unlock_inode(file->inode);
+
+done:
+ return DO_STATUS(errno);
+}
+
+__DEFINE_LXSYSCALL3(int, lseek, int, fd, int, offset, int, options)
+{
+ int errno = 0;
+ struct v_fd* fd_s;
+ if ((errno = vfs_getfd(fd, &fd_s))) {
+ goto done;
+ }
+
+ struct v_file* file = fd_s->file;
+
+ if (!file->ops->seek) {
+ errno = ENOTSUP;
+ goto done;
+ }
+
+ lock_inode(file->inode);
+
+ int overflow = 0;
+ int fpos = file->f_pos;
+ switch (options) {
+ case FSEEK_CUR:
+ overflow = __builtin_sadd_overflow((int)file->f_pos, offset, &fpos);
+ break;
+ case FSEEK_END:
+ overflow =
+ __builtin_sadd_overflow((int)file->inode->fsize, offset, &fpos);
+ break;
+ case FSEEK_SET:
+ fpos = offset;
+ break;
+ }
+ if (overflow) {
+ errno = EOVERFLOW;
+ } else if (!(errno = file->ops->seek(file->inode, fpos))) {
+ file->f_pos = fpos;
+ }
+
+ unlock_inode(file->inode);
+
+done:
+ 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 ENAMETOOLONG;
+ }
+
+ size_t len = 0;
+
+ if (dnode->parent != dnode) {
+ len = vfs_get_path(dnode->parent, buf, size, depth + 1);
+ }
+
+ if (len >= size) {
+ return len;
+ }
+
+ if (!len || buf[len - 1] != VFS_PATH_DELIM) {
+ buf[len++] = VFS_PATH_DELIM;
+ }
+
+ size_t cpy_size = MIN(dnode->name.len, size - len);
+ strncpy(buf + len, dnode->name.value, cpy_size);
+ len += cpy_size;
+
+ return len;
+}
+
+int
+vfs_readlink(struct v_dnode* dnode, char* buf, size_t size)
+{
+ const char* link;
+ struct v_inode* inode = dnode->inode;
+ if (inode->ops->read_symlink) {
+ lock_inode(inode);
+
+ int errno = inode->ops->read_symlink(inode, &link);
+ strncpy(buf, link, size);
+
+ unlock_inode(inode);
+ return errno;
+ }
+ return 0;
+}
+
+int
+vfs_get_dtype(int itype)
+{
+ if ((itype & VFS_IFSYMLINK)) {
+ return DT_SYMLINK;
+ } else if (!(itype & VFS_IFFILE)) {
+ return DT_DIR;
+ } else {
+ return DT_FILE;
+ }
+}
+
+__DEFINE_LXSYSCALL3(int, realpathat, int, fd, char*, buf, size_t, size)
+{
+ int errno;
+ struct v_fd* fd_s;
+ if ((errno = vfs_getfd(fd, &fd_s))) {
+ goto done;
+ }
+
+ struct v_dnode* dnode;
+ errno = vfs_get_path(fd_s->file->dnode, buf, size, 0);
+
+ if (errno >= 0) {
+ return errno;
+ }
+
+done:
+ 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_proc(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 ((errno = vfs_getfd(dirfd, &fd_s))) {
+ goto done;
+ }
+
+ pathname = pathname ? pathname : "";
+
+ 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);
+ }
+
+ if (errno >= 0) {
+ return errno;
+ }
+
+done:
+ return DO_STATUS(errno);
+}
+
+/*
+ NOTE
+ When we perform operation that could affect the layout of
+ directory (i.e., rename, mkdir, rmdir). We must lock the parent dir
+ whenever possible. This will blocking any ongoing path walking to reach
+ it hence avoid any partial state.
+*/
+
+__DEFINE_LXSYSCALL1(int, rmdir, const char*, pathname)
+{
+ int errno;
+ struct v_dnode* dnode;
+ if ((errno = vfs_walk_proc(pathname, &dnode, NULL, 0))) {
+ return DO_STATUS(errno);
+ }
+
+ lock_dnode(dnode);
+
+ if ((errno = vfs_check_writable(dnode))) {
+ goto done;
+ }
+
+ if ((dnode->super_block->fs->types & FSTYPE_ROFS)) {
+ errno = EROFS;
+ goto done;
+ }
+
+ if (dnode->ref_count > 1 || dnode->inode->open_count) {
+ errno = EBUSY;
+ goto done;
+ }
+
+ if (!llist_empty(&dnode->children)) {
+ errno = ENOTEMPTY;
+ goto done;
+ }
+
+ struct v_dnode* parent = dnode->parent;
+
+ if (!parent) {
+ errno = EINVAL;
+ goto done;
+ }
+
+ lock_dnode(parent);
+ lock_inode(parent->inode);
+
+ if (!(dnode->inode->itype & F_MFILE)) {
+ errno = parent->inode->ops->rmdir(parent->inode, dnode);
+ if (!errno) {
+ vfs_dcache_remove(dnode);
+ }
+ } else {
+ errno = ENOTDIR;
+ }
+
+ unlock_inode(parent->inode);
+ unlock_dnode(parent);
+
+done:
+ unlock_dnode(dnode);
+ return DO_STATUS(errno);
+}
+
+__DEFINE_LXSYSCALL1(int, mkdir, const char*, path)
+{
+ int errno = 0;
+ struct v_dnode *parent, *dir;
+ char name_value[VFS_NAME_MAXLEN];
+ struct hstr name = HHSTR(name_value, 0, 0);
+
+ if ((errno = vfs_walk_proc(path, &parent, &name, VFS_WALK_PARENT))) {
+ goto done;
+ }
+
+ if ((errno = vfs_check_writable(parent))) {
+ goto done;
+ }
+
+ if (!(dir = vfs_d_alloc(parent, &name))) {
+ errno = ENOMEM;
+ goto done;
+ }
+
+ lock_dnode(parent);
+ lock_inode(parent->inode);
+
+ if ((parent->super_block->fs->types & FSTYPE_ROFS)) {
+ errno = ENOTSUP;
+ } else if (!parent->inode->ops->mkdir) {
+ errno = ENOTSUP;
+ } else if ((parent->inode->itype & F_FILE)) {
+ errno = ENOTDIR;
+ } else if (!(errno = parent->inode->ops->mkdir(parent->inode, dir))) {
+ vfs_dcache_add(parent, dir);
+ goto cleanup;
+ }
+
+ vfs_d_free(dir);
+
+cleanup:
+ unlock_inode(parent->inode);
+ unlock_dnode(parent);
+done:
+ return DO_STATUS(errno);
+}
+
+int
+__vfs_do_unlink(struct v_dnode* dnode)
+{
+ int errno;
+ struct v_inode* inode = dnode->inode;
+
+ if (dnode->ref_count > 1) {
+ return EBUSY;
+ }
+
+ if ((errno = vfs_check_writable(dnode))) {
+ return errno;
+ }
+
+ lock_inode(inode);
+
+ if (inode->open_count) {
+ errno = EBUSY;
+ } else if ((inode->itype & F_MFILE)) {
+ errno = inode->ops->unlink(inode);
+ if (!errno) {
+ vfs_d_free(dnode);
+ }
+ } else {
+ errno = EISDIR;
+ }
+
+ unlock_inode(inode);
+
+ return errno;
+}
+
+__DEFINE_LXSYSCALL1(int, unlink, const char*, pathname)
+{
+ int errno;
+ struct v_dnode* dnode;
+ if ((errno = vfs_walk_proc(pathname, &dnode, NULL, 0))) {
+ goto done;
+ }
+
+ errno = __vfs_do_unlink(dnode);
+
+done:
+ return DO_STATUS(errno);
+}
+
+__DEFINE_LXSYSCALL2(int, unlinkat, int, fd, const char*, pathname)
+{
+ int errno;
+ struct v_fd* fd_s;
+ if ((errno = vfs_getfd(fd, &fd_s))) {
+ goto done;
+ }
+
+ struct v_dnode* dnode;
+ if (!(errno = vfs_walk(fd_s->file->dnode, pathname, &dnode, NULL, 0))) {
+ errno = __vfs_do_unlink(dnode);
+ }
+
+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_ONLY);
+ if (!errno) {
+ 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 (!(errno = vfs_getfd(fildes, &fd_s))) {
+ 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));
+
+ atomic_fetch_add(&old->file->ref_count, 1);
+
+ *new = copied;
+
+ return errno;
+}
+
+int
+vfs_dup2(int oldfd, int newfd)
+{
+ if (newfd == oldfd) {
+ return newfd;
+ }
+
+ int errno;
+ struct v_fd *oldfd_s, *newfd_s;
+ if ((errno = vfs_getfd(oldfd, &oldfd_s))) {
+ goto done;
+ }
+
+ if (!TEST_FD(newfd)) {
+ errno = EBADF;
+ goto done;
+ }
+
+ newfd_s = __current->fdtable->fds[newfd];
+ if (newfd_s && (errno = vfs_close(newfd_s->file))) {
+ 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_LXSYSCALL2(int, dup2, int, oldfd, int, newfd)
+{
+ return vfs_dup2(oldfd, newfd);
+}
+
+__DEFINE_LXSYSCALL1(int, dup, int, oldfd)
+{
+ int errno, newfd;
+ struct v_fd *oldfd_s, *newfd_s;
+ if ((errno = vfs_getfd(oldfd, &oldfd_s))) {
+ goto done;
+ }
+
+ if (!(errno = vfs_alloc_fdslot(&newfd)) &&
+ !(errno = vfs_dup_fd(oldfd_s, &newfd_s))) {
+ __current->fdtable->fds[newfd] = newfd_s;
+ return newfd;
+ }
+
+done:
+ return DO_STATUS(errno);
+}
+
+__DEFINE_LXSYSCALL2(int,
+ symlink,
+ const char*,
+ pathname,
+ const char*,
+ link_target)
+{
+ int errno;
+ struct v_dnode *dnode, *file;
+ if ((errno = __vfs_try_locate_file(
+ pathname, &dnode, &file, FLOCATE_CREATE_ONLY))) {
+ goto done;
+ }
+
+ if ((errno = vfs_check_writable(file))) {
+ goto done;
+ }
+
+ if (!file->inode->ops->set_symlink) {
+ errno = ENOTSUP;
+ goto done;
+ }
+
+ lock_inode(file->inode);
+
+ errno = file->inode->ops->set_symlink(file->inode, link_target);
+
+ unlock_inode(file->inode);
+
+done:
+ return DO_STATUS(errno);
+}
+
+void
+vfs_ref_file(struct v_file* file)
+{
+ atomic_fetch_add(&file->ref_count, 1);
+}
+
+void
+vfs_ref_dnode(struct v_dnode* dnode)
+{
+ atomic_fetch_add(&dnode->ref_count, 1);
+ mnt_mkbusy(dnode->mnt);
+}
+
+void
+vfs_unref_dnode(struct v_dnode* dnode)
+{
+ atomic_fetch_sub(&dnode->ref_count, 1);
+ mnt_chillax(dnode->mnt);
+}
+
+int
+vfs_do_chdir(struct proc_info* proc, struct v_dnode* dnode)
+{
+ int errno = 0;
+
+ lock_dnode(dnode);
+
+ if ((dnode->inode->itype & F_FILE)) {
+ errno = ENOTDIR;
+ goto done;
+ }
+
+ if (proc->cwd) {
+ vfs_unref_dnode(proc->cwd);
+ }
+
+ vfs_ref_dnode(dnode);
+ proc->cwd = dnode;
+
+ unlock_dnode(dnode);
+
+done:
+ return errno;
+}
+
+__DEFINE_LXSYSCALL1(int, chdir, const char*, path)
+{
+ struct v_dnode* dnode;
+ int errno = 0;
+
+ if ((errno = vfs_walk_proc(path, &dnode, NULL, 0))) {
+ goto done;
+ }
+
+ errno = vfs_do_chdir((struct proc_info*)__current, dnode);
+
+done:
+ return DO_STATUS(errno);
+}
+
+__DEFINE_LXSYSCALL1(int, fchdir, int, fd)
+{
+ struct v_fd* fd_s;
+ int errno = 0;
+
+ if ((errno = vfs_getfd(fd, &fd_s))) {
+ goto done;
+ }
+
+ errno = vfs_do_chdir((struct proc_info*)__current, fd_s->file->dnode);
+
+done:
+ return DO_STATUS(errno);
+}
+
+__DEFINE_LXSYSCALL2(char*, getcwd, char*, buf, size_t, size)
+{
+ int errno = 0;
+ char* ret_ptr = 0;
+ if (size < 2) {
+ errno = ERANGE;
+ goto done;
+ }
+
+ size_t len = 0;
+
+ if (!__current->cwd) {
+ *buf = VFS_PATH_DELIM;
+ len = 1;
+ } else {
+ len = vfs_get_path(__current->cwd, buf, size, 0);
+ if (len == size) {
+ errno = ERANGE;
+ goto done;
+ }
+ }
+
+ buf[len] = '\0';
+
+ ret_ptr = buf;
+
+done:
+ __current->k_status = errno;
+ return ret_ptr;
+}
+
+int
+vfs_do_rename(struct v_dnode* current, struct v_dnode* target)
+{
+ int errno = 0;
+ if (current->inode->id == target->inode->id) {
+ // hard link
+ return 0;
+ }
+
+ if ((errno = vfs_check_writable(current))) {
+ return errno;
+ }
+
+ if (current->ref_count > 1 || target->ref_count > 1) {
+ return EBUSY;
+ }
+
+ if (current->super_block != target->super_block) {
+ return EXDEV;
+ }
+
+ struct v_dnode* oldparent = current->parent;
+ struct v_dnode* newparent = target->parent;
+
+ lock_dnode(current);
+ lock_dnode(target);
+ if (oldparent)
+ lock_dnode(oldparent);
+ if (newparent)
+ lock_dnode(newparent);
+
+ if (!llist_empty(&target->children)) {
+ errno = ENOTEMPTY;
+ unlock_dnode(target);
+ goto cleanup;
+ }
+
+ if ((errno =
+ current->inode->ops->rename(current->inode, current, target))) {
+ unlock_dnode(target);
+ goto cleanup;
+ }
+
+ // re-position current
+ hstrcpy(¤t->name, &target->name);
+ vfs_dcache_rehash(newparent, current);
+
+ // detach target
+ vfs_d_free(target);
+
+ unlock_dnode(target);
+
+cleanup:
+ unlock_dnode(current);
+ if (oldparent)
+ unlock_dnode(oldparent);
+ if (newparent)
+ unlock_dnode(newparent);
+
+ return errno;
+}
+
+__DEFINE_LXSYSCALL2(int, rename, const char*, oldpath, const char*, newpath)
+{
+ struct v_dnode *cur, *target_parent, *target;
+ struct hstr name = HSTR(valloc(VFS_NAME_MAXLEN), 0);
+ int errno = 0;
+
+ if ((errno = vfs_walk_proc(oldpath, &cur, NULL, 0))) {
+ goto done;
+ }
+
+ if ((errno = vfs_walk(
+ __current->cwd, newpath, &target_parent, &name, VFS_WALK_PARENT))) {
+ goto done;
+ }
+
+ errno = vfs_walk(target_parent, name.value, &target, NULL, 0);
+ if (errno == ENOENT) {
+ target = vfs_d_alloc(target_parent, &name);
+ vfs_dcache_add(target_parent, target);
+ } else if (errno) {
+ goto done;
+ }
+
+ if (!target) {
+ errno = ENOMEM;
+ goto done;
+ }
+
+ errno = vfs_do_rename(cur, target);
+
+done:
+ vfree((void*)name.value);
+ return DO_STATUS(errno);
+}
+
+__DEFINE_LXSYSCALL2(int, fstat, int, fd, struct file_stat*, stat)
+{
+ int errno = 0;
+ struct v_fd* fds;
+
+ if ((errno = vfs_getfd(fd, &fds))) {
+ goto done;
+ }
+
+ struct v_inode* vino = fds->file->inode;
+ struct device* fdev = vino->sb->dev;
+
+ *stat = (struct file_stat){ .st_ino = vino->id,
+ .st_blocks = vino->lb_usage,
+ .st_size = vino->fsize,
+ .mode = vino->itype,
+ .st_ioblksize = PG_SIZE,
+ .st_blksize = vino->sb->blksize };
+
+ if (VFS_DEVFILE(vino->itype)) {
+ struct device* rdev = (struct device*)vino->data;
+ if (!rdev || rdev->magic != DEV_STRUCT_MAGIC) {
+ errno = EINVAL;
+ goto done;
+ }
+
+ stat->st_rdev = (dev_t){ .meta = rdev->class->meta,
+ .devident = device_id_from_class(rdev->class),
+ .dev_uid = rdev->dev_uid };
+ }
+
+ if (fdev) {
+ u32_t devident = device_id_from_class(fdev->class);
+ stat->st_dev = (dev_t){ .meta = fdev->class->meta,
+ .devident = devident,
+ .dev_uid = fdev->dev_uid };
+ }
+
+done:
+ return DO_STATUS(errno);
}
\ No newline at end of file
git://scm.lunaixsky.com / lunaix-os.git / blobdiff