From a428fcb46abd3647226d85ba79e5d39bf120d319 Mon Sep 17 00:00:00 2001 From: pumnflqv2 Date: Tue, 5 Jul 2022 05:04:12 +0800 Subject: [PATCH] ADD file via upload --- cur/linux/fs/super.c | 282 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 282 insertions(+) create mode 100644 cur/linux/fs/super.c diff --git a/cur/linux/fs/super.c b/cur/linux/fs/super.c new file mode 100644 index 0000000..6a4ccb1 --- /dev/null +++ b/cur/linux/fs/super.c @@ -0,0 +1,282 @@ +/* + * linux/fs/super.c + * + * (C) 1991 Linus Torvalds + */ + +/* + * super.c contains code to handle the super-block tables. + */ +#include +#include +#include +#include + +#include +#include + +int sync_dev(int dev); +void wait_for_keypress(void); + +/* set_bit uses setb, as gas doesn't recognize setc */ +#define set_bit(bitnr,addr) ({ \ +register int __res __asm__("ax"); \ +__asm__("bt %2,%3;setb %%al":"=a" (__res):"a" (0),"r" (bitnr),"m" (*(addr))); \ +__res; }) + +struct super_block super_block[NR_SUPER]; +/* this is initialized in init/main.c */ +int ROOT_DEV = 0; + +static void lock_super(struct super_block * sb) +{ + cli(); + while (sb->s_lock) + sleep_on(&(sb->s_wait)); + sb->s_lock = 1; + sti(); +} + +static void free_super(struct super_block * sb) +{ + cli(); + sb->s_lock = 0; + wake_up(&(sb->s_wait)); + sti(); +} + +static void wait_on_super(struct super_block * sb) +{ + cli(); + while (sb->s_lock) + sleep_on(&(sb->s_wait)); + sti(); +} + +struct super_block * get_super(int dev) +{ + struct super_block * s; + + if (!dev) + return NULL; + s = 0+super_block; + while (s < NR_SUPER+super_block) + if (s->s_dev == dev) { + wait_on_super(s); + if (s->s_dev == dev) + return s; + s = 0+super_block; + } else + s++; + return NULL; +} + +void put_super(int dev) +{ + struct super_block * sb; +/* struct m_inode * inode; */ + int i; + + if (dev == ROOT_DEV) { + printk("root diskette changed: prepare for armageddon\n\r"); + return; + } + if (!(sb = get_super(dev))) + return; + if (sb->s_imount) { + printk("Mounted disk changed - tssk, tssk\n\r"); + return; + } + lock_super(sb); + sb->s_dev = 0; + for(i=0;is_imap[i]); + for(i=0;is_zmap[i]); + free_super(sb); + return; +} + +static struct super_block * read_super(int dev) +{ + struct super_block * s; + struct buffer_head * bh; + int i,block; + + if (!dev) + return NULL; + check_disk_change(dev); + if (s = get_super(dev)) + return s; + for (s = 0+super_block ;; s++) { + if (s >= NR_SUPER+super_block) + return NULL; + if (!s->s_dev) + break; + } + s->s_dev = dev; + s->s_isup = NULL; + s->s_imount = NULL; + s->s_time = 0; + s->s_rd_only = 0; + s->s_dirt = 0; + lock_super(s); + if (!(bh = bread(dev,1))) { + s->s_dev=0; + free_super(s); + return NULL; + } + __asm__ volatile ("cld"); /* by wyj */ + *((struct d_super_block *) s) = + *((struct d_super_block *) bh->b_data); + brelse(bh); + if (s->s_magic != SUPER_MAGIC) { + s->s_dev = 0; + free_super(s); + return NULL; + } + for (i=0;is_imap[i] = NULL; + for (i=0;is_zmap[i] = NULL; + block=2; + for (i=0 ; i < s->s_imap_blocks ; i++) + if (s->s_imap[i]=bread(dev,block)) + block++; + else + break; + for (i=0 ; i < s->s_zmap_blocks ; i++) + if (s->s_zmap[i]=bread(dev,block)) + block++; + else + break; + if (block != 2+s->s_imap_blocks+s->s_zmap_blocks) { + for(i=0;is_imap[i]); + for(i=0;is_zmap[i]); + s->s_dev=0; + free_super(s); + return NULL; + } + s->s_imap[0]->b_data[0] |= 1; + s->s_zmap[0]->b_data[0] |= 1; + free_super(s); + return s; +} + +int sys_umount(char * dev_name) +{ + struct m_inode * inode; + struct super_block * sb; + int dev; + + if (!(inode=namei(dev_name))) + return -ENOENT; + dev = inode->i_zone[0]; + if (!S_ISBLK(inode->i_mode)) { + iput(inode); + return -ENOTBLK; + } + iput(inode); + if (dev==ROOT_DEV) + return -EBUSY; + if (!(sb=get_super(dev)) || !(sb->s_imount)) + return -ENOENT; + if (!sb->s_imount->i_mount) + printk("Mounted inode has i_mount=0\n"); + for (inode=inode_table+0 ; inodei_dev==dev && inode->i_count) + return -EBUSY; + sb->s_imount->i_mount=0; + iput(sb->s_imount); + sb->s_imount = NULL; + iput(sb->s_isup); + sb->s_isup = NULL; + put_super(dev); + sync_dev(dev); + return 0; +} + +int sys_mount(char * dev_name, char * dir_name, int rw_flag) +{ + struct m_inode * dev_i, * dir_i; + struct super_block * sb; + int dev; + + if (!(dev_i=namei(dev_name))) + return -ENOENT; + dev = dev_i->i_zone[0]; + if (!S_ISBLK(dev_i->i_mode)) { + iput(dev_i); + return -EPERM; + } + iput(dev_i); + if (!(dir_i=namei(dir_name))) + return -ENOENT; + if (dir_i->i_count != 1 || dir_i->i_num == ROOT_INO) { + iput(dir_i); + return -EBUSY; + } + if (!S_ISDIR(dir_i->i_mode)) { + iput(dir_i); + return -EPERM; + } + if (!(sb=read_super(dev))) { + iput(dir_i); + return -EBUSY; + } + if (sb->s_imount) { + iput(dir_i); + return -EBUSY; + } + if (dir_i->i_mount) { + iput(dir_i); + return -EPERM; + } + sb->s_imount=dir_i; + dir_i->i_mount=1; + dir_i->i_dirt=1; /* NOTE! we don't iput(dir_i) */ + return 0; /* we do that in umount */ +} + +void mount_root(void) +{ + int i,free; + struct super_block * p; + struct m_inode * mi; + + if (32 != sizeof (struct d_inode)) + panic("bad i-node size"); + for(i=0;is_dev = 0; + p->s_lock = 0; + p->s_wait = NULL; + } + if (!(p=read_super(ROOT_DEV))) + panic("Unable to mount root"); + if (!(mi=iget(ROOT_DEV,ROOT_INO))) + panic("Unable to read root i-node"); + mi->i_count += 3 ; /* NOTE! it is logically used 4 times, not 1 */ + p->s_isup = p->s_imount = mi; + current->pwd = mi; + current->root = mi; + free=0; + i=p->s_nzones; + while (-- i >= 0) + if (!set_bit(i&8191,p->s_zmap[i>>13]->b_data)) + free++; + printk("%d/%d free blocks\n\r",free,p->s_nzones); + free=0; + i=p->s_ninodes+1; + while (-- i >= 0) + if (!set_bit(i&8191,p->s_imap[i>>13]->b_data)) + free++; + printk("%d/%d free inodes\n\r",free,p->s_ninodes); +}