namei.c
上传用户:jlfgdled
上传日期:2013-04-10
资源大小:33168k
文件大小:2k
- /*
- * namei.c
- *
- * Copyright (c) 1999 Al Smith
- *
- * Portions derived from work (c) 1995,1996 Christian Vogelgsang.
- */
- #include <linux/string.h>
- #include <linux/efs_fs.h>
- static efs_ino_t efs_find_entry(struct inode *inode, const char *name, int len) {
- struct buffer_head *bh;
- int slot, namelen;
- char *nameptr;
- struct efs_dir *dirblock;
- struct efs_dentry *dirslot;
- efs_ino_t inodenum;
- efs_block_t block;
-
- if (inode->i_size & (EFS_DIRBSIZE-1))
- printk(KERN_WARNING "EFS: WARNING: find_entry(): directory size not a multiple of EFS_DIRBSIZEn");
- for(block = 0; block < inode->i_blocks; block++) {
- bh = sb_bread(inode->i_sb, efs_bmap(inode, block));
- if (!bh) {
- printk(KERN_ERR "EFS: find_entry(): failed to read dir block %dn", block);
- return 0;
- }
-
- dirblock = (struct efs_dir *) bh->b_data;
- if (be16_to_cpu(dirblock->magic) != EFS_DIRBLK_MAGIC) {
- printk(KERN_ERR "EFS: find_entry(): invalid directory blockn");
- brelse(bh);
- return(0);
- }
- for(slot = 0; slot < dirblock->slots; slot++) {
- dirslot = (struct efs_dentry *) (((char *) bh->b_data) + EFS_SLOTAT(dirblock, slot));
- namelen = dirslot->namelen;
- nameptr = dirslot->name;
- if ((namelen == len) && (!memcmp(name, nameptr, len))) {
- inodenum = be32_to_cpu(dirslot->inode);
- brelse(bh);
- return(inodenum);
- }
- }
- brelse(bh);
- }
- return(0);
- }
- struct dentry *efs_lookup(struct inode *dir, struct dentry *dentry) {
- efs_ino_t inodenum;
- struct inode * inode;
- if (!dir || !S_ISDIR(dir->i_mode))
- return ERR_PTR(-ENOENT);
- inode = NULL;
- inodenum = efs_find_entry(dir, dentry->d_name.name, dentry->d_name.len);
- if (inodenum) {
- if (!(inode = iget(dir->i_sb, inodenum)))
- return ERR_PTR(-EACCES);
- }
- d_add(dentry, inode);
- return NULL;
- }