/* * linux/fs/inode.c * * (C) 1991 Linus Torvalds */ #include <linux/string.h> #include <linux/stat.h> #include <linux/sched.h> #include <linux/kernel.h> #include <linux/mm.h> #include <asm/system.h> struct inode inode_table[NR_INODE]={{0,},}; static inline void wait_on_inode(struct inode * inode) { cli(); while (inode->i_lock) sleep_on(&inode->i_wait); sti(); } static inline void lock_inode(struct inode * inode) { cli(); while (inode->i_lock) sleep_on(&inode->i_wait); inode->i_lock=1; sti(); } static inline void unlock_inode(struct inode * inode) { inode->i_lock=0; wake_up(&inode->i_wait); } static void write_inode(struct inode * inode) { if (!inode->i_dirt) return; inode->i_dirt = 0; lock_inode(inode); if (inode->i_dev && inode->i_sb && inode->i_sb->s_op && inode->i_sb->s_op->write_inode) inode->i_sb->s_op->write_inode(inode); unlock_inode(inode); } static void read_inode(struct inode * inode) { lock_inode(inode); if (inode->i_sb && inode->i_sb->s_op && inode->i_sb->s_op->read_inode) inode->i_sb->s_op->read_inode(inode); unlock_inode(inode); } /* * bmap is needed for demand-loading and paging: if this function * doesn't exist for a filesystem, then those things are impossible: * executables cannot be run from the filesystem etc... * * This isn't as bad as it sounds: the read-routines might still work, * so the filesystem would be otherwise ok (for example, you might have * a DOS filesystem, which doesn't lend itself to bmap very well, but * you could still transfer files to/from the filesystem) */ int bmap(struct inode * inode, int block) { if (inode->i_op && inode->i_op->bmap) return inode->i_op->bmap(inode,block); return 0; } void invalidate_inodes(int dev) { int i; struct inode * inode; inode = 0+inode_table; for(i=0 ; i<NR_INODE ; i++,inode++) { wait_on_inode(inode); if (inode->i_dev == dev) { if (inode->i_count) { printk("inode in use on removed disk\n\r"); continue; } inode->i_dev = inode->i_dirt = 0; } } } void sync_inodes(void) { int i; struct inode * inode; inode = 0+inode_table; for(i=0 ; i<NR_INODE ; i++,inode++) { wait_on_inode(inode); if (inode->i_dirt) write_inode(inode); } } void iput(struct inode * inode) { if (!inode) return; wait_on_inode(inode); if (!inode->i_count) { printk("iput: trying to free free inode\n"); printk("device %04x, inode %d, mode=%07o\n",inode->i_rdev, inode->i_ino,inode->i_mode); return; } if (inode->i_pipe) { wake_up(&inode->i_wait); wake_up(&inode->i_wait2); } repeat: if (inode->i_count>1) { inode->i_count--; return; } if (inode->i_pipe) { free_page(inode->i_size); inode->i_size = 0; } if (!inode->i_dev) { inode->i_count--; return; } if (!inode->i_nlink) { if (inode->i_sb && inode->i_sb->s_op && inode->i_sb->s_op->put_inode) { inode->i_sb->s_op->put_inode(inode); return; } } if (inode->i_dirt) { write_inode(inode); /* we can sleep - so do again */ wait_on_inode(inode); goto repeat; } inode->i_count--; return; } struct inode * get_empty_inode(void) { struct inode * inode; static struct inode * last_inode = inode_table; int i; do { inode = NULL; for (i = NR_INODE; i ; i--) { if (++last_inode >= inode_table + NR_INODE) last_inode = inode_table; if (!last_inode->i_count) { inode = last_inode; if (!inode->i_dirt && !inode->i_lock) break; } } if (!inode) { for (i=0 ; i<NR_INODE ; i++) printk("(%04x: %d (%o)) ",inode_table[i].i_dev, inode_table[i].i_ino,inode_table[i].i_mode); panic("No free inodes in mem"); } wait_on_inode(inode); while (inode->i_dirt) { write_inode(inode); wait_on_inode(inode); } } while (inode->i_count); memset(inode,0,sizeof(*inode)); inode->i_count = 1; return inode; } struct inode * get_pipe_inode(void) { struct inode * inode; if (!(inode = get_empty_inode())) return NULL; if (!(inode->i_size = get_free_page())) { inode->i_count = 0; return NULL; } inode->i_count = 2; /* sum of readers/writers */ PIPE_HEAD(*inode) = PIPE_TAIL(*inode) = 0; PIPE_READERS(*inode) = PIPE_WRITERS(*inode) = 1; inode->i_pipe = 1; return inode; } struct inode * iget(int dev,int nr) { struct inode * inode, * empty; if (!dev) panic("iget with dev==0"); empty = get_empty_inode(); inode = inode_table; while (inode < NR_INODE+inode_table) { if (inode->i_dev != dev || inode->i_ino != nr) { inode++; continue; } wait_on_inode(inode); if (inode->i_dev != dev || inode->i_ino != nr) { inode = inode_table; continue; } inode->i_count++; if (inode->i_mount) { int i; for (i = 0 ; i<NR_SUPER ; i++) if (super_block[i].s_covered==inode) break; if (i >= NR_SUPER) { printk("Mounted inode hasn't got sb\n"); if (empty) iput(empty); return inode; } iput(inode); if (!(inode = super_block[i].s_mounted)) printk("iget: mounted dev has no rootinode\n"); else { inode->i_count++; wait_on_inode(inode); } } if (empty) iput(empty); return inode; } if (!empty) return (NULL); inode = empty; if (!(inode->i_sb = get_super(dev))) { printk("iget: gouldn't get super-block\n\t"); iput(inode); return NULL; } inode->i_dev = dev; inode->i_ino = nr; read_inode(inode); return inode; }