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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 | /* * dir.c * * Copyright (c) 1999 Al Smith */ #include <linux/efs_fs.h> static int efs_readdir(struct file *, void *, filldir_t); static struct file_operations efs_dir_operations = { NULL, /* lseek */ NULL, /* read */ NULL, /* write */ efs_readdir, /* readdir */ NULL, /* poll */ NULL, /* ioctl */ NULL, /* mmap */ NULL, /* open */ NULL, /* flush */ NULL, /* release */ NULL, /* fsync */ NULL, /* fasync */ NULL, /* check_media_change */ NULL /* revalidate */ }; extern int efs_get_block(struct inode *, long, struct buffer_head *, int); struct inode_operations efs_dir_inode_operations = { &efs_dir_operations, /* default directory file-ops */ NULL, /* create */ efs_lookup, /* lookup */ NULL, /* link */ NULL, /* unlink */ NULL, /* symlink */ NULL, /* mkdir */ NULL, /* rmdir */ NULL, /* mknod */ NULL, /* rename */ NULL, /* readlink */ NULL, /* follow_link */ efs_get_block, /* get_block */ NULL, /* readpage */ NULL, /* writepage */ NULL, /* truncate */ NULL, /* permission */ NULL /* revalidate */ }; static int efs_readdir(struct file *filp, void *dirent, filldir_t filldir) { struct inode *inode = filp->f_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 || !S_ISDIR(inode->i_mode)) return -EBADF; if (inode->i_size & (EFS_DIRBSIZE-1)) printk(KERN_WARNING "EFS: WARNING: readdir(): directory size not a multiple of EFS_DIRBSIZE\n"); /* 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 = bread(inode->i_dev, efs_bmap(inode, block), EFS_DIRBSIZE); 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); /* 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; return 0; } slot++; } brelse(bh); slot = 0; block++; } filp->f_pos = (block << EFS_DIRBSIZE_BITS) | slot; return 0; } |