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