X-Git-Url: https://scm.lunaixsky.com/lunaix-os.git/blobdiff_plain/6fefc6f5af83f316e18b0cb9dbbde1cea0b98add..c50398ab4cb09658b3b3fff74804d2f26df785e7:/lunaix-os/kernel/fs/vfs.c diff --git a/lunaix-os/kernel/fs/vfs.c b/lunaix-os/kernel/fs/vfs.c index 09668f5..476b00b 100644 --- a/lunaix-os/kernel/fs/vfs.c +++ b/lunaix-os/kernel/fs/vfs.c @@ -9,6 +9,40 @@ * */ +// 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] :: composition +*/ + #include #include #include @@ -20,11 +54,7 @@ #include #include -#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 static struct cake_pile* dnode_pile; static struct cake_pile* inode_pile; @@ -32,16 +62,14 @@ static struct cake_pile* file_pile; static struct cake_pile* superblock_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* -vfs_d_alloc(); +struct lru_zone *dnode_lru, *inode_lru; -void -vfs_d_free(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* vfs_sb_alloc(); @@ -49,6 +77,12 @@ vfs_sb_alloc(); void 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() { @@ -60,35 +94,49 @@ vfs_init() superblock_pile = cake_new_pile("sb_cache", sizeof(struct v_superblock), 1, 0); - dnode_cache = vzalloc(DNODE_HASHTABLE_SIZE * sizeof(struct hbucket)); + 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); + + hstr_rehash(&vfs_ddot, HSTR_FULL_HASH); + hstr_rehash(&vfs_dot, HSTR_FULL_HASH); - // 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) +__dcache_hash(struct v_dnode* parent, uint32_t* hash) { + uint32_t _hash = *hash; // 与parent的指针值做加法，来减小碰撞的可能性。 - hash += (uint32_t)parent; + _hash += (uint32_t)parent; // 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); + *hash = _hash; + return &dnode_cache[_hash & VFS_HASH_MASK]; } 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; - struct hbucket* slot = __dcache_get_bucket(parent, str->hash); + if (HSTR_EQ(str, &vfs_ddot)) { + return parent->parent; + } + + uint32_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; } } @@ -98,223 +146,171 @@ vfs_dcache_lookup(struct v_dnode* parent, struct hstr* str) 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, - struct hstr* component, - int walk_options) +void +vfs_dcache_remove(struct v_dnode* dnode) { - int errno = 0; - int i = 0, j = 0; - - if (path[0] == PATH_DELIM || !start) { - if ((walk_options & VFS_WALK_FSRELATIVE) && start) { - start = start->super_block->root; - } else { - start = root_sb->root; - } - i++; - } - - 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 = path[i++], lookahead; - while (current) { - lookahead = path[i++]; - if (current != PATH_DELIM) { - if (j >= VFS_NAME_MAXLEN - 1) { - return ENAMETOOLONG; - } - if (!VFS_VALID_CHAR(current)) { - return VFS_EINVLD; - } - name_content[j++] = current; - if (lookahead) { - goto cont; - } - } + assert(dnode); + assert(dnode->ref_count == 1); - // handling cases like /^.*(\/+).*$/ - if (lookahead == PATH_DELIM) { - goto cont; - } + llist_delete(&dnode->siblings); + hlist_delete(&dnode->hash_list); - name_content[j] = 0; - name.len = j; - hstr_rehash(&name, HSTR_FULL_HASH); + dnode->parent = NULL; + atomic_fetch_sub(&dnode->ref_count, 1); +} - if (!lookahead && (walk_options & VFS_WALK_PARENT)) { - if (component) { - component->hash = name.hash; - component->len = j; - strcpy(component->value, name_content); - } - break; - } +void +vfs_dcache_rehash(struct v_dnode* new_parent, struct v_dnode* dnode) +{ + assert(new_parent); - dnode = vfs_dcache_lookup(current_level, &name); + hstr_rehash(&dnode->name, HSTR_FULL_HASH); + vfs_dcache_remove(dnode); + vfs_dcache_add(new_parent, dnode); +} - if (!dnode) { - dnode = vfs_d_alloc(); - dnode->name = HSTR(valloc(VFS_NAME_MAXLEN), j); - dnode->name.hash = name.hash; +int +vfs_open(struct v_dnode* dnode, struct v_file** file) +{ + if (!dnode->inode || !dnode->inode->ops->open) { + return ENOTSUP; + } - strcpy(dnode->name.value, name_content); + struct v_inode* inode = dnode->inode; - errno = - current_level->inode->ops.dir_lookup(current_level->inode, dnode); + lock_inode(inode); - if (errno == ENOENT && (walk_options & VFS_WALK_MKPARENT)) { - if (!current_level->inode->ops.mkdir) { - errno = ENOTSUP; - } else { - errno = current_level->inode->ops.mkdir( - current_level->inode, dnode); - } - } + struct v_file* vfile = cake_grab(file_pile); + memset(vfile, 0, sizeof(*vfile)); - if (errno) { - goto error; - } + vfile->dnode = dnode; + vfile->inode = inode; + vfile->ref_count = ATOMIC_VAR_INIT(1); + vfile->ops = inode->default_fops; - vfs_dcache_add(current_level, dnode); + if ((inode->itype & VFS_IFFILE) && !inode->pg_cache) { + struct pcache* pcache = vzalloc(sizeof(struct pcache)); + pcache_init(pcache); + pcache->master = inode; + inode->pg_cache = pcache; + } - dnode->parent = current_level; - llist_append(¤t_level->children, &dnode->siblings); - } + 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); - j = 0; - current_level = dnode; - cont: - current = lookahead; - }; + *file = vfile; + } - *dentry = current_level; - return 0; + unlock_inode(inode); -error: - vfree(dnode->name.value); - vfs_d_free(dnode); - *dentry = NULL; return errno; } -int -vfs_mount(const char* target, const char* fs_name, bdev_t device) +void +vfs_assign_inode(struct v_dnode* assign_to, struct v_inode* inode) { - int errno; - struct v_dnode* mnt; - - if (!(errno = vfs_walk(NULL, target, &mnt, NULL, 0))) { - errno = vfs_mount_at(fs_name, device, mnt); + if (assign_to->inode) { + assign_to->inode->link_count--; } - - return errno; + assign_to->inode = inode; + inode->link_count++; } int -vfs_unmount(const char* target) +vfs_link(struct v_dnode* to_link, struct v_dnode* name) { int errno; - struct v_dnode* mnt; - if (!(errno = vfs_walk(NULL, target, &mnt, NULL, 0))) { - errno = vfs_unmount_at(mnt); + if ((errno = vfs_check_writable(to_link))) { + return errno; } - return errno; -} - -int -vfs_mount_at(const char* fs_name, bdev_t device, struct v_dnode* mnt_point) -{ - struct filesystem* fs = fsm_get(fs_name); - if (!fs) - return VFS_ENOFS; - struct v_superblock* sb = vfs_sb_alloc(); - sb->dev = device; - sb->fs_id = fs_id++; - - int errno = 0; - if (!(errno = fs->mount(sb, mnt_point))) { - sb->fs = fs; - sb->root = mnt_point; - mnt_point->super_block = sb; - llist_append(&root_sb->sb_list, &sb->sb_list); + 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_at(struct v_dnode* mnt_point) +vfs_close(struct v_file* file) { int errno = 0; - struct v_superblock* sb = mnt_point->super_block; - if (!sb) { - return VFS_EBADMNT; - } - if (!(errno = sb->fs->unmount(sb))) { - struct v_dnode* fs_root = sb->root; - llist_delete(&fs_root->siblings); - llist_delete(&sb->sb_list); - vfs_sb_free(sb); + 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--; + + // Remove 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. + // FIXME is this a good solution? + /* + * Consider two process both open the same file both with fd=x. + * Process A: busy on reading x + * Process B: do nothing with x + * Assume 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. + * + * A possible solution is to add a owner identification in the lock + * context, so only the lock holder can do the release. + */ + if (mutex_on_hold(&file->inode->lock)) { + unlock_inode(file->inode); + } + mnt_chillax(file->dnode->mnt); + + pcache_commit_all(file->inode); + cake_release(file_pile, file); } return errno; } int -vfs_open(struct v_dnode* dnode, struct v_file** file) +vfs_fsync(struct v_file* file) { - if (!dnode->inode || !dnode->inode->ops.open) { - return ENOTSUP; + int errno; + if ((errno = vfs_check_writable(file->dnode))) { + return errno; } - struct v_file* vfile = cake_grab(file_pile); - memset(vfile, 0, sizeof(*vfile)); + lock_inode(file->inode); - int errno = dnode->inode->ops.open(dnode->inode, vfile); - if (errno) { - cake_release(file_pile, vfile); - } else { - *file = vfile; - } - return errno; -} + pcache_commit_all(file->inode); -int -vfs_close(struct v_file* file) -{ - if (!file->ops.close) { - return ENOTSUP; + errno = ENOTSUP; + if (file->ops->sync) { + errno = file->ops->sync(file); } - int errno = file->ops.close(file); - if (!errno) { - cake_release(file_pile, file); - } - return errno; -} + unlock_inode(file->inode); -int -vfs_fsync(struct v_file* file) -{ - int errno = ENOTSUP; - if (file->ops.sync) { - errno = file->ops.sync(file); - } - if (!errno && file->inode->ops.sync) { - return file->inode->ops.sync(file->inode); - } return errno; } @@ -336,98 +332,268 @@ vfs_sb_alloc() struct v_superblock* sb = cake_grab(superblock_pile); memset(sb, 0, sizeof(*sb)); llist_init_head(&sb->sb_list); + sb->i_cache = vzalloc(VFS_HASHTABLE_SIZE * sizeof(struct hbucket)); return sb; } void vfs_sb_free(struct v_superblock* sb) { + 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* -vfs_d_alloc() +vfs_d_alloc(struct v_dnode* parent, struct hstr* name) { struct v_dnode* dnode = cake_grab(dnode_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); + 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 vfs_d_free(struct v_dnode* dnode) { - if (dnode->ops.destruct) { - dnode->ops.destruct(dnode); + 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(dnode->name.value); cake_release(dnode_pile, dnode); } struct v_inode* -vfs_i_alloc() +vfs_i_find(struct v_superblock* sb, uint32_t i_id) { - struct v_inode* inode = cake_grab(inode_pile); + 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); + sb->ops.init_inode(sb, inode); + + inode->sb = sb; + inode->ctime = clock_unixtime(); + inode->atime = inode->ctime; + inode->mtime = inode->ctime; + +done: + 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); + } + inode->ops->sync(inode); + hlist_delete(&inode->hash_list); cake_release(inode_pile, inode); } -__DEFINE_LXSYSCALL2(int, open, const char*, path, int, options) +/* ---- System call definition and support ---- */ + +#define FLOCATE_CREATE_EMPTY 1 + +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); - struct v_dnode *dentry, *file; - int errno, fd; - if ((errno = vfs_walk(NULL, path, &dentry, &name, VFS_WALK_PARENT))) { - return -1; + int errno; + + name_str[0] = 0; + if ((errno = vfs_walk_proc(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; - } + 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 { - errno = vfs_open(file, &opened_file); + vfs_d_free(file_new); } - __current->k_status = errno; + unlock_dnode(parent); + + return errno; +} + +int +vfs_do_open(const char* path, int options) +{ + int errno, fd; + struct v_dnode *dentry, *file; + struct v_file* ofile = 0; + + errno = __vfs_try_locate_file( + path, &dentry, &file, (options & FO_CREATE) ? FLOCATE_CREATE_EMPTY : 0); + + if (errno || (errno = vfs_open(file, &ofile))) { + return errno; + } + + struct v_inode* o_inode = ofile->inode; if (!errno && !(errno = vfs_alloc_fdslot(&fd))) { struct v_fd* fd_s = vzalloc(sizeof(*fd_s)); - fd_s->file = opened_file; - fd_s->pos = 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; } - return SYSCALL_ESTATUS(errno); + return errno; } -#define GET_FD(fd, fd_s) \ - (fd >= 0 && fd < VFS_MAX_FD && (fd_s = __current->fdtable->fds[fd])) +__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; - if (!GET_FD(fd, fd_s)) { - errno = EBADF; - } else if (!(errno = vfs_close(fd_s->file))) { - vfree(fd_s); - __current->fdtable->fds[fd] = 0; + int errno = 0; + if ((errno = vfs_getfd(fd, &fd_s))) { + goto done_err; } - __current->k_status = errno; + if ((errno = vfs_close(fd_s->file))) { + goto done_err; + } - return SYSCALL_ESTATUS(errno); + vfree(fd_s); + __current->fdtable->fds[fd] = 0; + +done_err: + return DO_STATUS(errno); } void @@ -446,9 +612,16 @@ __DEFINE_LXSYSCALL2(int, readdir, int, fd, struct dirent*, dent) { struct v_fd* fd_s; int errno; - if (!GET_FD(fd, fd_s)) { - errno = EBADF; - } else if (!(fd_s->file->inode->itype & VFS_INODE_TYPE_DIR)) { + + if ((errno = vfs_getfd(fd, &fd_s))) { + goto done; + } + + struct v_inode* inode = fd_s->file->inode; + + lock_inode(inode); + + if (!(inode->itype & VFS_IFDIR)) { errno = ENOTDIR; } else { struct dir_context dctx = @@ -456,105 +629,765 @@ __DEFINE_LXSYSCALL2(int, readdir, int, fd, struct dirent*, dent) .index = dent->d_offset, .read_complete_callback = __vfs_readdir_callback }; - if (!(errno = fd_s->file->ops.readdir(fd_s->file, &dctx))) { - dent->d_offset++; + 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++; } - __current->k_status = errno; - return SYSCALL_ESTATUS(errno); + unlock_inode(inode); + +done: + return DO_STATUS_OR_RETURN(errno); } -__DEFINE_LXSYSCALL1(int, mkdir, const char*, path) +__DEFINE_LXSYSCALL3(int, read, int, fd, void*, buf, size_t, count) { - struct v_dnode *parent, *dir; - struct hstr component = HSTR(valloc(VFS_NAME_MAXLEN), 0); - int errno = vfs_walk(NULL, path, &parent, &component, VFS_WALK_PARENT); - if (errno) { + int errno = 0; + struct v_fd* fd_s; + if ((errno = vfs_getfd(fd, &fd_s))) { goto done; } - if (!parent->inode->ops.mkdir) { - errno = ENOTSUP; - } else if (!(parent->inode->itype & VFS_INODE_TYPE_DIR)) { - errno = ENOTDIR; - } else { - dir = vfs_d_alloc(); - dir->name = component; - if (!(errno = parent->inode->ops.mkdir(parent->inode, dir))) { - llist_append(&parent->children, &dir->siblings); - } else { - vfs_d_free(dir); - vfree(component.value); - } + struct v_file* file = fd_s->file; + if ((file->inode->itype & VFS_IFDIR)) { + errno = EISDIR; + goto done; } -done: - __current->k_status = errno; - return SYSCALL_ESTATUS(errno); -} + lock_inode(file->inode); -__DEFINE_LXSYSCALL3(int, read, int, fd, void*, buf, size_t, count) -{ - int errno = 0; - struct v_fd* fd_s; - if (!GET_FD(fd, fd_s)) { - errno = EBADF; + 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 { - 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; - } + errno = pcache_read(file->inode, buf, count, file->f_pos); } - __current->k_status = errno; - return SYSCALL_ESTATUS(errno); + 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 (!GET_FD(fd, fd_s)) { - errno = EBADF; + 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 & VFS_IFDIR)) { + 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 { - 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; - } + errno = pcache_write(file->inode, buf, count, file->f_pos); } - __current->k_status = errno; - return SYSCALL_ESTATUS(errno); + 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 (!GET_FD(fd, fd_s)) { - errno = EBADF; - } else { - size_t fpos = fd_s->file->f_pos; - switch (options) { - case FSEEK_CUR: - fpos = (size_t)((int)fd_s->file->f_pos + offset); - break; - case FSEEK_END: - fpos = (size_t)((int)fd_s->file->inode->fsize + offset); - break; - case FSEEK_SET: - fpos = offset; - break; - - default: - break; - } - fd_s->pos = fpos; + 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 || dnode->parent == dnode) { + return 0; + } + + if (depth > 64) { + return ENAMETOOLONG; + } + + size_t len = vfs_get_path(dnode->parent, buf, size, depth + 1); + + if (len >= size) { + return len; + } + + 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) +{ + switch (itype) { + case VFS_IFDIR: + return DT_DIR; + case VFS_IFSYMLINK: + return DT_SYMLINK; + default: + return DT_PIPE; + } +} + +__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; + } + + 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 & VFS_IFDIR)) { + 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 & VFS_IFDIR)) { + 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 & VFS_IFDIR)) { + // The underlying unlink implementation should handle + // symlink case + 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_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 (!(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; + if ((errno = vfs_walk_proc(pathname, &dnode, NULL, 0))) { + goto done; + } + + if (errno = vfs_check_writable(dnode)) { + goto done; + } + + if (!dnode->inode->ops->set_symlink) { + errno = ENOTSUP; + goto done; + } + + lock_inode(dnode->inode); + + errno = dnode->inode->ops->set_symlink(dnode->inode, link_target); + + unlock_inode(dnode->inode); + +done: + return DO_STATUS(errno); +} + +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 & VFS_IFDIR)) { + 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(__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(__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 + 1] = '\0'; + + ret_ptr = buf; + +done: __current->k_status = errno; - return SYSCALL_ESTATUS(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(name.value); + return DO_STATUS(errno); } \ No newline at end of file