// mount 挂载sfs文件系统
static int
sfs_do_mount(struct device *dev, struct fs **fs_store) {
static_assert(SFS_BLKSIZE >= sizeof(struct sfs_super));
static_assert(SFS_BLKSIZE >= sizeof(struct sfs_disk_inode));
static_assert(SFS_BLKSIZE >= sizeof(struct sfs_disk_entry));
if (dev->d_blocksize != SFS_BLKSIZE) {
return -E_NA_DEV;
}
/* allocate fs structure */
struct fs *fs;
// 我要稍微说一下这里的sfs,alloc_fs以及fsop_info只是一个宏而已，展开之后就做了一系列的替换
// 所以sfs只是字符而已，不要大惊小怪
if ((fs = alloc_fs(sfs)) == NULL) { // 首先是分配一个fs结构，并且指定了类型
return -E_NO_MEM;
}
struct sfs_fs *sfs = fsop_info(fs, sfs); // 得到fs里面的__sfs_info结构的指针
sfs->dev = dev; // sfs主要是用于记录文件系统的一些信息
int ret = -E_NO_MEM;
void *sfs_buffer;
if ((sfs->sfs_buffer = sfs_buffer = kmalloc(SFS_BLKSIZE)) == NULL) { // 分配buffer
goto failed_cleanup_fs;
}
/* load and check superblock */
// 加载和检查超级块
if ((ret = sfs_init_read(dev, SFS_BLKN_SUPER, sfs_buffer)) != 0) {
goto failed_cleanup_sfs_buffer;
}
// 第一个扇区的东西就是超级块吗？
ret = -E_INVAL;
struct sfs_super *super = sfs_buffer;
if (super->magic != SFS_MAGIC) {
cprintf("sfs: wrong magic in superblock. (%08x should be %08x).\n",
super->magic, SFS_MAGIC);
goto failed_cleanup_sfs_buffer;
}
if (super->blocks > dev->d_blocks) {
cprintf("sfs: fs has %u blocks, device has %u blocks.\n",
super->blocks, dev->d_blocks);
goto failed_cleanup_sfs_buffer;
}
super->info[SFS_MAX_INFO_LEN] = '\0';
sfs->super = *super; // 记录下超级块的信息
ret = -E_NO_MEM;
uint32_t i;
/* alloc and initialize hash list */
// 分配和初始化hash list
list_entry_t *hash_list;
if ((sfs->hash_list = hash_list = kmalloc(sizeof(list_entry_t) * SFS_HLIST_SIZE)) == NULL) {
goto failed_cleanup_sfs_buffer;
}
for (i = 0; i < SFS_HLIST_SIZE; i ++) { // 为什么要分配那么多的hash_list?
list_init(hash_list + i); // 都需要初始化
}
/* load and check freemap */
// 加载和检查freemap
struct bitmap *freemap;
uint32_t freemap_size_nbits = sfs_freemap_bits(super);
if ((sfs->freemap = freemap = bitmap_create(freemap_size_nbits)) == NULL) {
goto failed_cleanup_hash_list;
}
uint32_t freemap_size_nblks = sfs_freemap_blocks(super);
if ((ret = sfs_init_freemap(dev, freemap, SFS_BLKN_FREEMAP, freemap_size_nblks, sfs_buffer)) != 0) {
goto failed_cleanup_freemap;
}
uint32_t blocks = sfs->super.blocks, unused_blocks = 0;
for (i = 0; i < freemap_size_nbits; i ++) {
if (bitmap_test(freemap, i)) {
unused_blocks ++;
}
}
assert(unused_blocks == sfs->super.unused_blocks);
/* and other fields */
sfs->super_dirty = 0;
sem_init(&(sfs->fs_sem), 1);
sem_init(&(sfs->io_sem), 1);
sem_init(&(sfs->mutex_sem), 1);
list_init(&(sfs->inode_list));
cprintf("sfs: mount: '%s' (%d/%d/%d)\n", sfs->super.info,
blocks - unused_blocks, unused_blocks, blocks);
/* link addr of sync/get_root/unmount/cleanup funciton fs's function pointers*/
fs->fs_sync = sfs_sync;
fs->fs_get_root = sfs_get_root;
fs->fs_unmount = sfs_unmount;
fs->fs_cleanup = sfs_cleanup;
*fs_store = fs;
return 0;
failed_cleanup_freemap:
bitmap_destroy(freemap);
failed_cleanup_hash_list:
kfree(hash_list);
failed_cleanup_sfs_buffer:
kfree(sfs_buffer);
failed_cleanup_fs:
kfree(fs);
return ret;
}
static int
sfs_do_mount(struct device *dev, struct fs **fs_store) {
/*
* Make sure SFS on-disk structures aren't messed up
*/
static_assert(SFS_BLKSIZE >= sizeof(struct sfs_super));
static_assert(SFS_BLKSIZE >= sizeof(struct sfs_disk_inode));
static_assert(SFS_BLKSIZE >= sizeof(struct sfs_disk_entry));
/*
* We can't mount on devices with the wrong sector size.
*
* (Note: for all intents and purposes here, "sector" and
* "block" are interchangeable terms. Technically a filesystem
* block may be composed of several hardware sectors, but we
* don't do that in sfs.)
*/
if (dev->d_blocksize != SFS_BLKSIZE) {
return -E_NA_DEV;
}
/* allocate fs structure */
struct fs *fs;
if ((fs = alloc_fs(sfs)) == NULL) {
return -E_NO_MEM;
}
/* get sfs from fs.fs_info.__sfs_info */
struct sfs_fs *sfs = fsop_info(fs, sfs);
sfs->dev = dev;
int ret = -E_NO_MEM;
void *sfs_buffer;
if ((sfs->sfs_buffer = sfs_buffer = kmalloc(SFS_BLKSIZE)) == NULL) {
goto failed_cleanup_fs;
}
/* load and check sfs's superblock */
if ((ret = sfs_init_read(dev, SFS_BLKN_SUPER, sfs_buffer)) != 0) {
goto failed_cleanup_sfs_buffer;
}
ret = -E_INVAL;
struct sfs_super *super = sfs_buffer;
/* Make some simple sanity checks */
if (super->magic != SFS_MAGIC) {
cprintf("sfs: wrong magic in superblock. (%08x should be %08x).\n",
super->magic, SFS_MAGIC);
goto failed_cleanup_sfs_buffer;
}
if (super->blocks > dev->d_blocks) {
cprintf("sfs: fs has %u blocks, device has %u blocks.\n",
super->blocks, dev->d_blocks);
goto failed_cleanup_sfs_buffer;
}
super->info[SFS_MAX_INFO_LEN] = '\0';
sfs->super = *super;
ret = -E_NO_MEM;
uint32_t i;
/* alloc and initialize hash list */
list_entry_t *hash_list;
if ((sfs->hash_list = hash_list = kmalloc(sizeof(list_entry_t) * SFS_HLIST_SIZE)) == NULL) {
goto failed_cleanup_sfs_buffer;
}
for (i = 0; i < SFS_HLIST_SIZE; i ++) {
list_init(hash_list + i);
}
/* load and check freemap (free space bitmap in disk) */
struct bitmap *freemap;
uint32_t freemap_size_nbits = sfs_freemap_bits(super);
if ((sfs->freemap = freemap = bitmap_create(freemap_size_nbits)) == NULL) {
goto failed_cleanup_hash_list;
}
uint32_t freemap_size_nblks = sfs_freemap_blocks(super);
if ((ret = sfs_init_freemap(dev, freemap, SFS_BLKN_FREEMAP, freemap_size_nblks, sfs_buffer)) != 0) {
goto failed_cleanup_freemap;
}
uint32_t blocks = sfs->super.blocks, unused_blocks = 0;
for (i = 0; i < freemap_size_nbits; i ++) {
if (bitmap_test(freemap, i)) {
unused_blocks ++;
}
}
assert(unused_blocks == sfs->super.unused_blocks);
/* and other fields */
sfs->super_dirty = 0;
sem_init(&(sfs->fs_sem), 1);
sem_init(&(sfs->io_sem), 1);
sem_init(&(sfs->mutex_sem), 1);
list_init(&(sfs->inode_list));
cprintf("sfs: mount: '%s' (%d/%d/%d)\n", sfs->super.info,
blocks - unused_blocks, unused_blocks, blocks);
/* Set up abstract fs calls */
fs->fs_sync = sfs_sync;
fs->fs_get_root = sfs_get_root;
fs->fs_unmount = sfs_unmount;
fs->fs_cleanup = sfs_cleanup;
*fs_store = fs;
return 0;
failed_cleanup_freemap:
bitmap_destroy(freemap);
failed_cleanup_hash_list:
kfree(hash_list);
failed_cleanup_sfs_buffer:
kfree(sfs_buffer);
failed_cleanup_fs:
kfree(fs);
return ret;
}
static int
sfs_do_mount(struct device *dev, struct fs **fs_store) {
static_assert(SFS_BLKSIZE >= sizeof(struct sfs_super));
static_assert(SFS_BLKSIZE >= sizeof(struct sfs_disk_inode));
static_assert(SFS_BLKSIZE >= sizeof(struct sfs_disk_entry));
if (dev->d_blocksize != SFS_BLKSIZE) {
return -E_NA_DEV;
}
/* allocate fs structure */
struct fs *fs;
if ((fs = alloc_fs(sfs)) == NULL) {
return -E_NO_MEM;
}
struct sfs_fs *sfs = fsop_info(fs, sfs);
sfs->dev = dev;
int ret = -E_NO_MEM;
void *sfs_buffer;
if ((sfs->sfs_buffer = sfs_buffer = kmalloc(SFS_BLKSIZE)) == NULL) {
goto failed_cleanup_fs;
}
/* load and check superblock */
if ((ret = sfs_init_read(dev, SFS_BLKN_SUPER, sfs_buffer)) != 0) {
goto failed_cleanup_sfs_buffer;
}
ret = -E_INVAL;
struct sfs_super *super = sfs_buffer;
if (super->magic != SFS_MAGIC) {
kprintf("sfs: wrong magic in superblock. (%08x should be %08x).\n",
super->magic, SFS_MAGIC);
goto failed_cleanup_sfs_buffer;
}
if (super->blocks > dev->d_blocks) {
kprintf("sfs: fs has %u blocks, device has %u blocks.\n",
super->blocks, dev->d_blocks);
goto failed_cleanup_sfs_buffer;
}
super->info[SFS_MAX_INFO_LEN] = '\0';
sfs->super = *super;
ret = -E_NO_MEM;
uint32_t i;
/* alloc and initialize hash list */
list_entry_t *hash_list;
if ((sfs->hash_list = hash_list = kmalloc(sizeof(list_entry_t) * SFS_HLIST_SIZE)) == NULL) {
goto failed_cleanup_sfs_buffer;
}
for (i = 0; i < SFS_HLIST_SIZE; i ++) {
list_init(hash_list + i);
}
/* load and check freemap */
struct bitmap *freemap;
uint32_t freemap_size_nbits = sfs_freemap_bits(super);
if ((sfs->freemap = freemap = bitmap_create(freemap_size_nbits)) == NULL) {
goto failed_cleanup_hash_list;
}
uint32_t freemap_size_nblks = sfs_freemap_blocks(super);
if ((ret = sfs_init_freemap(dev, freemap, SFS_BLKN_FREEMAP, freemap_size_nblks, sfs_buffer)) != 0) {
goto failed_cleanup_freemap;
}
uint32_t blocks = sfs->super.blocks, unused_blocks = 0;
for (i = 0; i < freemap_size_nbits; i ++) {
if (bitmap_test(freemap, i)) {
unused_blocks ++;
}
}
kprintf("unused_blocks is %d and super->unused_blocks is %d", \
unused_blocks, sfs->super.unused_blocks);
// while (1);
assert(unused_blocks == sfs->super.unused_blocks);
/* and other fields */
sfs->super_dirty = 0;
sem_init(&(sfs->fs_sem), 1);
sem_init(&(sfs->io_sem), 1);
sem_init(&(sfs->mutex_sem), 1);
list_init(&(sfs->inode_list));
kprintf("sfs: mount: '%s' (%d/%d/%d)\n", sfs->super.info,
blocks - unused_blocks, unused_blocks, blocks);
fs->fs_sync = sfs_sync;
fs->fs_get_root = sfs_get_root;
fs->fs_unmount = sfs_unmount;
fs->fs_cleanup = sfs_cleanup;
*fs_store = fs;
return 0;
failed_cleanup_freemap:
bitmap_destroy(freemap);
failed_cleanup_hash_list:
kfree(hash_list);
failed_cleanup_sfs_buffer:
kfree(sfs_buffer);
failed_cleanup_fs:
kfree(fs);
return ret;
}
