/* * dir.c * * Copyright (c) 1999 Al Smith */ #include <linux/buffer_head.h> #include <linux/smp_lock.h> #include "efs.h" static int efs_readdir(struct file *, void *, filldir_t); const struct file_operations efs_dir_operations = { .read = generic_read_dir, .readdir = efs_readdir, }; const struct inode_operations efs_dir_inode_operations = { .lookup = efs_lookup, }; static int efs_readdir(struct file *filp, void *dirent, filldir_t filldir) { struct inode *inode = filp->f_path.dentry->d_inode; struct buffer_head *bh; struct efs_dir *dirblock; struct efs_dentry *dirslot; efs_ino_t inodenum; efs_block_t block; int slot, namelen; char *nameptr; if (inode->i_size & (EFS_DIRBSIZE-1)) printk(KERN_WARNING "EFS: WARNING: readdir(): directory size not a multiple of EFS_DIRBSIZE\n"); lock_kernel(); /* work out where this entry can be found */ block = filp->f_pos >> EFS_DIRBSIZE_BITS; /* each block contains at most 256 slots */ slot = filp->f_pos & 0xff; /* look at all blocks */ while (block < inode->i_blocks) { /* read the dir block */ bh = sb_bread(inode->i_sb, efs_bmap(inode, block)); if (!bh) { printk(KERN_ERR "EFS: readdir(): failed to read dir block %d\n", block); break; } dirblock = (struct efs_dir *) bh->b_data; if (be16_to_cpu(dirblock->magic) != EFS_DIRBLK_MAGIC) { printk(KERN_ERR "EFS: readdir(): invalid directory block\n"); brelse(bh); break; } while (slot < dirblock->slots) { if (dirblock->space[slot] == 0) { slot++; continue; } dirslot = (struct efs_dentry *) (((char *) bh->b_data) + EFS_SLOTAT(dirblock, slot)); inodenum = be32_to_cpu(dirslot->inode); namelen = dirslot->namelen; nameptr = dirslot->name; #ifdef DEBUG printk(KERN_DEBUG "EFS: readdir(): block %d slot %d/%d: inode %u, name \"%s\", namelen %u\n", block, slot, dirblock->slots-1, inodenum, nameptr, namelen); #endif if (namelen > 0) { /* found the next entry */ filp->f_pos = (block << EFS_DIRBSIZE_BITS) | slot; /* copy filename and data in dirslot */ filldir(dirent, nameptr, namelen, filp->f_pos, inodenum, DT_UNKNOWN); /* sanity check */ if (nameptr - (char *) dirblock + namelen > EFS_DIRBSIZE) { printk(KERN_WARNING "EFS: directory entry %d exceeds directory block\n", slot); slot++; continue; } /* store position of next slot */ if (++slot == dirblock->slots) { slot = 0; block++; } brelse(bh); filp->f_pos = (block << EFS_DIRBSIZE_BITS) | slot; goto out; } slot++; } brelse(bh); slot = 0; block++; } filp->f_pos = (block << EFS_DIRBSIZE_BITS) | slot; out: unlock_kernel(); return 0; }