support statfs, check whether target directory is empty and fail on non-empty for rmdir

include/files.h

@@ -24,6 +24,7 @@ public:
     void unlink_inode(u_int64_t inode_number);
     u_int64_t disk_namei(const char* path);
     u_int64_t namei(const char* path);
+    bool dir_empty(u_int64_t inode_number);
     int fischl_mkdir(const char*, mode_t);
     int fischl_mknod(const char*, mode_t, dev_t);//for special file
     int fischl_access(const char* path, int mask);

include/fs.hpp

@@ -12,7 +12,7 @@ class DatablockOperation;
 
 class Fs {
 public:
-  Fs(RawDisk *disk);
+  Fs(RawDisk *disk, bool load, u_int64_t user_inode_blocks = 0);
   ~Fs();
 
   ssize_t read(INode_Data *inode_data, char buf[], size_t count, size_t offset);
@@ -35,6 +35,8 @@ public:
 
   int save_free_list_head(u_int64_t new_free_list_head);
   int save_inode_list_head(u_int64_t new_inode_list_head);
+  void update_num_used_inodes(int delta);
+  void update_num_used_datablocks(int delta);
 
   int sweep_inode_datablocks(INode_Data *inode_data,
                              u_int64_t start_block_index, bool allocate,

include/fs/fs_data_types.hpp

@@ -15,6 +15,10 @@ class SuperBlock_Data {
 public:
   u_int64_t free_list_head;
   u_int64_t inode_list_head;
+  u_int64_t num_inode_blocks;
+  u_int64_t num_used_inodes;
+  u_int64_t num_data_blocks;
+  u_int64_t num_used_data_blocks;
   SuperBlock_Data();
   void serialize(char buf[]);
   void deserialize(char buf[]);

lib/files.cpp

@@ -501,6 +501,25 @@ int FilesOperation::fischl_readdir(const char *path, void *buf,
   return 0;
 }
 
+bool FilesOperation::dir_empty(u_int64_t inode_number) {
+  INode_Data inode;
+  inode.inode_num = inode_number;
+  fs->inode_manager->load_inode(&inode);
+  char buffer[IO_BLOCK_SIZE] = {0};
+  for (u_int64_t idx = 0; idx < inode.metadata.size / IO_BLOCK_SIZE; idx++) {
+    fs->read(&inode, buffer, IO_BLOCK_SIZE, idx * IO_BLOCK_SIZE);
+    DirectoryEntry ent;
+    for (int i = 0; i <= IO_BLOCK_SIZE - 264; i += 264) {
+      ent.deserialize(buffer + i);
+      if (ent.inode_number && strcmp(ent.file_name, ".") &&
+          strcmp(ent.file_name, "..")) {
+        return false;
+      }
+    }
+  }
+  return true;
+}
+
 int FilesOperation::fischl_releasedir(const char *path,
                                       struct fuse_file_info *fi) {
   if (fischl_load_entry(root_node, path) == NULL)
@@ -559,6 +578,16 @@ int FilesOperation::fischl_opendir(const char *path,
 }
 
 int FilesOperation::fischl_rmdir(const char *path) {
+  u_int64_t fh = namei(path);
+  if (fh == -1) {
+    return -ENOENT;
+  }
+  printf("in rmdir\n");
+  if(!dir_empty(fh)){
+    return -ENOTEMPTY;
+  }
+  printf("rmdir: not empty\n");
+  
   char *pathdup = strdup(path);
   char *lastSlash = strrchr(pathdup, '/');
   *lastSlash = '\0';
@@ -1324,10 +1353,11 @@ int FilesOperation::fischl_utimens(const char *path,
 
 int FilesOperation::fischl_statfs(const char *path, struct statvfs *stbuf) {
   stbuf->f_bsize = 4096;
-  stbuf->f_blocks = 0;
-  stbuf->f_bfree = 0;
-  stbuf->f_files = 0;
-  stbuf->f_ffree = 0;
+  stbuf->f_frsize = IO_BLOCK_SIZE;
+  stbuf->f_blocks = fs->superblock.num_data_blocks;
+  stbuf->f_bfree = fs->superblock.num_data_blocks - fs->superblock.num_used_data_blocks;
+  stbuf->f_files = fs->superblock.num_inode_blocks * 8;
+  stbuf->f_ffree = fs->superblock.num_inode_blocks * 8 - fs->superblock.num_used_inodes;
   stbuf->f_namemax = 256;
   return 0;
-}
+}

lib/fischl.cpp

@@ -226,8 +226,21 @@ int fischl(int argc, char *argv[])
         printf("WRONG l/n ARGUMENTS\n");
         return 0;
     }
-    options.fs = new Fs(options.H);
-    if(!options.load){
+    if(options.load){
+        options.fs = new Fs(options.H, true);
+    }
+    else{
+        uint64_t total_blocks = options.H->diskSize / IO_BLOCK_SIZE;
+        uint64_t max_inode_blocks = options.H->diskSize / IO_BLOCK_SIZE - 2 - DATABLOCKS_PER_BITMAP_BLOCK;
+        printf("The block device contains %llu blocks\n", total_blocks);
+        printf("Choose the number of blocks to store inodes: 1 ~ %llu\n", max_inode_blocks);
+        uint64_t user_inode_blocks;
+        scanf("%llu", &user_inode_blocks);
+        if (user_inode_blocks < 1 || user_inode_blocks > max_inode_blocks) {
+            printf("Invalid number of blocks to store inodes\n");
+            return -1;
+        }
+        options.fs = new Fs(options.H, false, user_inode_blocks);
         printf("FORMAT %d\n", options.fs->format());
     }
     options.fsop = new FilesOperation(*options.H, options.fs);
@@ -311,4 +324,4 @@ int fischl(int argc, char *argv[])
 	ret = fuse_main(args.argc, args.argv, &fischl_oper, NULL);
 	fuse_opt_free_args(&args);
 	return ret;
-}
+}

lib/fs/datablock_manager.cpp

@@ -88,6 +88,8 @@ int DataBlock_Manager_Bitmap::new_datablock(u_int64_t *block_num) {
     return err;
 
   (*block_num) = block_num_;
+  fs->update_num_used_datablocks(1);
+  
   return 0;
 }
 
@@ -119,6 +121,7 @@ int DataBlock_Manager_Bitmap::free_datablock(u_int64_t block_num) {
     if ((err = fs->save_free_list_head(bitmap_block_num)) < 0)
       return err;
 
+  fs->update_num_used_datablocks(-1);
   return 0;
 
   // placing almost full bitmaps back at start of freelist is slow

lib/fs/fs.cpp

@@ -1,13 +1,25 @@
 #include "fs.hpp"
 #include <assert.h>
 
-Fs::Fs(RawDisk *disk) : disk(disk) {
-  assert((disk->diskSize / IO_BLOCK_SIZE) >
-         2 + NUM_INODE_BLOCKS + DATABLOCKS_PER_BITMAP_BLOCK);
+Fs::Fs(RawDisk *disk, bool load, uint64_t user_inode_blocks) : disk(disk) {
   superblock = SuperBlock_Data();
-  inode_manager = new INode_Manager_Freelist(this, 1, 1 + NUM_INODE_BLOCKS);
+  // Determine the num inode blocks
+  uint64_t num_inode_blocks = 0; // The superblock is not loaded from disk here; it is done in FilesOperation::initialize called by fischl_init
+  if(load) {
+    load_superblock();
+    num_inode_blocks = superblock.num_inode_blocks;
+  } else {
+    num_inode_blocks = user_inode_blocks;
+    superblock.num_inode_blocks = num_inode_blocks;
+    superblock.num_used_inodes = 0;
+    superblock.num_data_blocks = disk->diskSize / IO_BLOCK_SIZE - 1 - num_inode_blocks;
+    superblock.num_used_data_blocks = 0;
+  }
+  assert((disk->diskSize / IO_BLOCK_SIZE) >
+         2 + num_inode_blocks + DATABLOCKS_PER_BITMAP_BLOCK);
+  inode_manager = new INode_Manager_Freelist(this, 1, 1 + num_inode_blocks);
   datablock_manager = new DataBlock_Manager_Bitmap(
-      this, 1 + NUM_INODE_BLOCKS, disk->diskSize / IO_BLOCK_SIZE);
+      this, 1 + num_inode_blocks, disk->diskSize / IO_BLOCK_SIZE);
 };
 
 Fs::~Fs() {
@@ -68,4 +80,12 @@ int Fs::save_inode_list_head(u_int64_t new_inode_list_head) {
     return err;
   }
   return 0;
+}
+
+void Fs::update_num_used_inodes(int delta) {
+  superblock.num_used_inodes += delta;
+}
+
+void Fs::update_num_used_datablocks(int delta) {
+  superblock.num_used_data_blocks += delta;
 }

lib/fs/fs_data_types.cpp

@@ -36,18 +36,27 @@ size_t read_u32(u_int32_t *num, char buf[]) {
 SuperBlock_Data::SuperBlock_Data() {
   free_list_head = 0;
   inode_list_head = 0;
+  num_inode_blocks = 0;
 }
 
 void SuperBlock_Data::serialize(char buf[]) {
   size_t i = 0;
   i += write_u64(free_list_head, &buf[i]);
   i += write_u64(inode_list_head, &buf[i]);
+  i += write_u64(num_inode_blocks, &buf[i]);
+  i += write_u64(num_used_inodes, &buf[i]);
+  i += write_u64(num_data_blocks, &buf[i]);
+  i += write_u64(num_used_data_blocks, &buf[i]);
 }
 
 void SuperBlock_Data::deserialize(char buf[]) {
   size_t i = 0;
   i += read_u64(&free_list_head, &buf[i]);
   i += read_u64(&inode_list_head, &buf[i]);
+  i += read_u64(&num_inode_blocks, &buf[i]);
+  i += read_u64(&num_used_inodes, &buf[i]);
+  i += read_u64(&num_data_blocks, &buf[i]);
+  i += read_u64(&num_used_data_blocks, &buf[i]);
 }
 
 INode_Data::INode_Data(u_int64_t inode_num) : inode_num(inode_num) {

lib/fs/inode_manager.cpp

@@ -88,6 +88,7 @@ int INode_Manager_Freelist::new_inode(u_int64_t uid, u_int64_t gid,
     inode_data->inode_num = 0xFFFFFFFFFFFFFFFF;
     return err;
   }
+  fs->update_num_used_inodes(1);
 
   return 0;
 }
@@ -111,6 +112,7 @@ int INode_Manager_Freelist::free_inode(INode_Data *inode_data) {
 
   if ((err = fs->save_inode_list_head(inode_data->inode_num)) < 0)
     return err;
+  fs->update_num_used_inodes(-1);
 
   return 0;
 }