From ace9429bb58fd418f0c81d4c2835699bddf6bde6 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Thu, 11 Apr 2024 10:27:49 +0200 Subject: Adding upstream version 6.6.15. Signed-off-by: Daniel Baumann --- fs/qnx4/dir.c | 117 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 117 insertions(+) create mode 100644 fs/qnx4/dir.c (limited to 'fs/qnx4/dir.c') diff --git a/fs/qnx4/dir.c b/fs/qnx4/dir.c new file mode 100644 index 0000000000..66645a5a35 --- /dev/null +++ b/fs/qnx4/dir.c @@ -0,0 +1,117 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * QNX4 file system, Linux implementation. + * + * Version : 0.2.1 + * + * Using parts of the xiafs filesystem. + * + * History : + * + * 28-05-1998 by Richard Frowijn : first release. + * 20-06-1998 by Frank Denis : Linux 2.1.99+ & dcache support. + */ + +#include +#include "qnx4.h" + +/* + * A qnx4 directory entry is an inode entry or link info + * depending on the status field in the last byte. The + * first byte is where the name start either way, and a + * zero means it's empty. + * + * Also, due to a bug in gcc, we don't want to use the + * real (differently sized) name arrays in the inode and + * link entries, but always the 'de_name[]' one in the + * fake struct entry. + * + * See + * + * https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99578#c6 + * + * for details, but basically gcc will take the size of the + * 'name' array from one of the used union entries randomly. + * + * This use of 'de_name[]' (48 bytes) avoids the false positive + * warnings that would happen if gcc decides to use 'inode.di_name' + * (16 bytes) even when the pointer and size were to come from + * 'link.dl_name' (48 bytes). + * + * In all cases the actual name pointer itself is the same, it's + * only the gcc internal 'what is the size of this field' logic + * that can get confused. + */ +union qnx4_directory_entry { + struct { + const char de_name[48]; + u8 de_pad[15]; + u8 de_status; + }; + struct qnx4_inode_entry inode; + struct qnx4_link_info link; +}; + +static int qnx4_readdir(struct file *file, struct dir_context *ctx) +{ + struct inode *inode = file_inode(file); + unsigned int offset; + struct buffer_head *bh; + unsigned long blknum; + int ix, ino; + int size; + + QNX4DEBUG((KERN_INFO "qnx4_readdir:i_size = %ld\n", (long) inode->i_size)); + QNX4DEBUG((KERN_INFO "pos = %ld\n", (long) ctx->pos)); + + while (ctx->pos < inode->i_size) { + blknum = qnx4_block_map(inode, ctx->pos >> QNX4_BLOCK_SIZE_BITS); + bh = sb_bread(inode->i_sb, blknum); + if (bh == NULL) { + printk(KERN_ERR "qnx4_readdir: bread failed (%ld)\n", blknum); + return 0; + } + ix = (ctx->pos >> QNX4_DIR_ENTRY_SIZE_BITS) % QNX4_INODES_PER_BLOCK; + for (; ix < QNX4_INODES_PER_BLOCK; ix++, ctx->pos += QNX4_DIR_ENTRY_SIZE) { + union qnx4_directory_entry *de; + + offset = ix * QNX4_DIR_ENTRY_SIZE; + de = (union qnx4_directory_entry *) (bh->b_data + offset); + + if (!de->de_name[0]) + continue; + if (!(de->de_status & (QNX4_FILE_USED|QNX4_FILE_LINK))) + continue; + if (!(de->de_status & QNX4_FILE_LINK)) { + size = sizeof(de->inode.di_fname); + ino = blknum * QNX4_INODES_PER_BLOCK + ix - 1; + } else { + size = sizeof(de->link.dl_fname); + ino = ( le32_to_cpu(de->link.dl_inode_blk) - 1 ) * + QNX4_INODES_PER_BLOCK + + de->link.dl_inode_ndx; + } + size = strnlen(de->de_name, size); + QNX4DEBUG((KERN_INFO "qnx4_readdir:%.*s\n", size, name)); + if (!dir_emit(ctx, de->de_name, size, ino, DT_UNKNOWN)) { + brelse(bh); + return 0; + } + } + brelse(bh); + } + return 0; +} + +const struct file_operations qnx4_dir_operations = +{ + .llseek = generic_file_llseek, + .read = generic_read_dir, + .iterate_shared = qnx4_readdir, + .fsync = generic_file_fsync, +}; + +const struct inode_operations qnx4_dir_inode_operations = +{ + .lookup = qnx4_lookup, +}; -- cgit v1.2.3