1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * QNX4 file system, Linux implementation. 4 * 5 * Version : 0.2.1 6 * 7 * Using parts of the xiafs filesystem. 8 * 9 * History : 10 * 11 * 28-05-1998 by Richard Frowijn : first release. 12 * 20-06-1998 by Frank Denis : Linux 2.1.99+ & dcache support. 13 */ 14 15 #include <linux/buffer_head.h> 16 #include "qnx4.h" 17 18 /* 19 * A qnx4 directory entry is an inode entry or link info 20 * depending on the status field in the last byte. The 21 * first byte is where the name start either way, and a 22 * zero means it's empty. 23 */ 24 union qnx4_directory_entry { 25 struct { 26 char de_name; 27 char de_pad[62]; 28 char de_status; 29 }; 30 struct qnx4_inode_entry inode; 31 struct qnx4_link_info link; 32 }; 33 34 static int qnx4_readdir(struct file *file, struct dir_context *ctx) 35 { 36 struct inode *inode = file_inode(file); 37 unsigned int offset; 38 struct buffer_head *bh; 39 unsigned long blknum; 40 int ix, ino; 41 int size; 42 43 QNX4DEBUG((KERN_INFO "qnx4_readdir:i_size = %ld\n", (long) inode->i_size)); 44 QNX4DEBUG((KERN_INFO "pos = %ld\n", (long) ctx->pos)); 45 46 while (ctx->pos < inode->i_size) { 47 blknum = qnx4_block_map(inode, ctx->pos >> QNX4_BLOCK_SIZE_BITS); 48 bh = sb_bread(inode->i_sb, blknum); 49 if (bh == NULL) { 50 printk(KERN_ERR "qnx4_readdir: bread failed (%ld)\n", blknum); 51 return 0; 52 } 53 ix = (ctx->pos >> QNX4_DIR_ENTRY_SIZE_BITS) % QNX4_INODES_PER_BLOCK; 54 for (; ix < QNX4_INODES_PER_BLOCK; ix++, ctx->pos += QNX4_DIR_ENTRY_SIZE) { 55 union qnx4_directory_entry *de; 56 const char *name; 57 58 offset = ix * QNX4_DIR_ENTRY_SIZE; 59 de = (union qnx4_directory_entry *) (bh->b_data + offset); 60 61 if (!de->de_name) 62 continue; 63 if (!(de->de_status & (QNX4_FILE_USED|QNX4_FILE_LINK))) 64 continue; 65 if (!(de->de_status & QNX4_FILE_LINK)) { 66 size = sizeof(de->inode.di_fname); 67 name = de->inode.di_fname; 68 ino = blknum * QNX4_INODES_PER_BLOCK + ix - 1; 69 } else { 70 size = sizeof(de->link.dl_fname); 71 name = de->link.dl_fname; 72 ino = ( le32_to_cpu(de->link.dl_inode_blk) - 1 ) * 73 QNX4_INODES_PER_BLOCK + 74 de->link.dl_inode_ndx; 75 } 76 size = strnlen(name, size); 77 QNX4DEBUG((KERN_INFO "qnx4_readdir:%.*s\n", size, name)); 78 if (!dir_emit(ctx, name, size, ino, DT_UNKNOWN)) { 79 brelse(bh); 80 return 0; 81 } 82 } 83 brelse(bh); 84 } 85 return 0; 86 } 87 88 const struct file_operations qnx4_dir_operations = 89 { 90 .llseek = generic_file_llseek, 91 .read = generic_read_dir, 92 .iterate_shared = qnx4_readdir, 93 .fsync = generic_file_fsync, 94 }; 95 96 const struct inode_operations qnx4_dir_inode_operations = 97 { 98 .lookup = qnx4_lookup, 99 }; 100