Resguardo inicial

linux-7.2.3/fs/isofs/Kconfig

@@ -0,0 +1,41 @@
+# SPDX-License-Identifier: GPL-2.0-only
+config ISO9660_FS
+	tristate "ISO 9660 CDROM file system support"
+	select BUFFER_HEAD
+	help
+	  This is the standard file system used on CD-ROMs.  It was previously
+	  known as "High Sierra File System" and is called "hsfs" on other
+	  Unix systems.  The so-called Rock-Ridge extensions which allow for
+	  long Unix filenames and symbolic links are also supported by this
+	  driver.  If you have a CD-ROM drive and want to do more with it than
+	  just listen to audio CDs and watch its LEDs, say Y (and read
+	  <file:Documentation/filesystems/isofs.rst> and the CD-ROM-HOWTO,
+	  available from <http://www.tldp.org/docs.html#howto>), thereby
+	  enlarging your kernel by about 27 KB; otherwise say N.
+
+	  To compile this file system support as a module, choose M here: the
+	  module will be called isofs.
+
+config JOLIET
+	bool "Microsoft Joliet CDROM extensions"
+	depends on ISO9660_FS
+	select NLS
+	help
+	  Joliet is a Microsoft extension for the ISO 9660 CD-ROM file system
+	  which allows for long filenames in unicode format (unicode is the
+	  new 16 bit character code, successor to ASCII, which encodes the
+	  characters of almost all languages of the world; see
+	  <http://www.unicode.org/> for more information).  Say Y here if you
+	  want to be able to read Joliet CD-ROMs under Linux.
+
+config ZISOFS
+	bool "Transparent decompression extension"
+	depends on ISO9660_FS
+	select ZLIB_INFLATE
+	help
+	  This is a Linux-specific extension to RockRidge which lets you store
+	  data in compressed form on a CD-ROM and have it transparently
+	  decompressed when the CD-ROM is accessed.  See
+	  <http://www.kernel.org/pub/linux/utils/fs/zisofs/> for the tools
+	  necessary to create such a filesystem.  Say Y here if you want to be
+	  able to read such compressed CD-ROMs.

linux-7.2.3/fs/isofs/Makefile

@@ -0,0 +1,10 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Makefile for the Linux isofs filesystem routines.
+#
+
+obj-$(CONFIG_ISO9660_FS) += isofs.o
+
+isofs-y 		:= namei.o inode.o dir.o util.o rock.o export.o
+isofs-$(CONFIG_JOLIET)	+= joliet.o
+isofs-$(CONFIG_ZISOFS)	+= compress.o

linux-7.2.3/fs/isofs/compress.c

@@ -0,0 +1,383 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* -*- linux-c -*- ------------------------------------------------------- *
+ *   
+ *   Copyright 2001 H. Peter Anvin - All Rights Reserved
+ *
+ * ----------------------------------------------------------------------- */
+
+/*
+ * linux/fs/isofs/compress.c
+ *
+ * Transparent decompression of files on an iso9660 filesystem
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/bio.h>
+
+#include <linux/slab.h>
+#include <linux/vmalloc.h>
+#include <linux/zlib.h>
+
+#include "isofs.h"
+#include "zisofs.h"
+
+/* This should probably be global. */
+static char zisofs_sink_page[PAGE_SIZE];
+
+/*
+ * This contains the zlib memory allocation and the mutex for the
+ * allocation; this avoids failures at block-decompression time.
+ */
+static void *zisofs_zlib_workspace;
+static DEFINE_MUTEX(zisofs_zlib_lock);
+
+/*
+ * Read data of @inode from @block_start to @block_end and uncompress
+ * to one zisofs block. Store the data in the @pages array with @pcount
+ * entries. Start storing at offset @poffset of the first page.
+ */
+static loff_t zisofs_uncompress_block(struct inode *inode, loff_t block_start,
+				      loff_t block_end, int pcount,
+				      struct page **pages, unsigned poffset,
+				      int *errp)
+{
+	unsigned int zisofs_block_shift = ISOFS_I(inode)->i_format_parm[1];
+	unsigned int bufsize = ISOFS_BUFFER_SIZE(inode);
+	unsigned int bufshift = ISOFS_BUFFER_BITS(inode);
+	unsigned int bufmask = bufsize - 1;
+	int i, block_size = block_end - block_start;
+	z_stream stream = { .total_out = 0,
+			    .avail_in = 0,
+			    .avail_out = 0, };
+	int zerr;
+	int needblocks = (block_size + (block_start & bufmask) + bufmask)
+				>> bufshift;
+	int haveblocks;
+	blkcnt_t blocknum;
+	struct buffer_head **bhs;
+	int curbh, curpage;
+
+	if (block_size > deflateBound(1UL << zisofs_block_shift)) {
+		*errp = -EIO;
+		return 0;
+	}
+	/* Empty block? */
+	if (block_size == 0) {
+		for ( i = 0 ; i < pcount ; i++ ) {
+			if (!pages[i])
+				continue;
+			memzero_page(pages[i], 0, PAGE_SIZE);
+			SetPageUptodate(pages[i]);
+		}
+		return ((loff_t)pcount) << PAGE_SHIFT;
+	}
+
+	/* Because zlib is not thread-safe, do all the I/O at the top. */
+	blocknum = block_start >> bufshift;
+	bhs = kzalloc_objs(*bhs, needblocks + 1);
+	if (!bhs) {
+		*errp = -ENOMEM;
+		return 0;
+	}
+	haveblocks = isofs_get_blocks(inode, blocknum, bhs, needblocks);
+	bh_read_batch(haveblocks, bhs);
+
+	curbh = 0;
+	curpage = 0;
+	/*
+	 * First block is special since it may be fractional.  We also wait for
+	 * it before grabbing the zlib mutex; odds are that the subsequent
+	 * blocks are going to come in in short order so we don't hold the zlib
+	 * mutex longer than necessary.
+	 */
+
+	if (!bhs[0])
+		goto b_eio;
+
+	wait_on_buffer(bhs[0]);
+	if (!buffer_uptodate(bhs[0])) {
+		*errp = -EIO;
+		goto b_eio;
+	}
+
+	stream.workspace = zisofs_zlib_workspace;
+	mutex_lock(&zisofs_zlib_lock);
+		
+	zerr = zlib_inflateInit(&stream);
+	if (zerr != Z_OK) {
+		if (zerr == Z_MEM_ERROR)
+			*errp = -ENOMEM;
+		else
+			*errp = -EIO;
+		printk(KERN_DEBUG "zisofs: zisofs_inflateInit returned %d\n",
+			       zerr);
+		goto z_eio;
+	}
+
+	while (curpage < pcount && curbh < haveblocks &&
+	       zerr != Z_STREAM_END) {
+		if (!stream.avail_out) {
+			if (pages[curpage]) {
+				stream.next_out = kmap_local_page(pages[curpage])
+						+ poffset;
+				stream.avail_out = PAGE_SIZE - poffset;
+				poffset = 0;
+			} else {
+				stream.next_out = (void *)&zisofs_sink_page;
+				stream.avail_out = PAGE_SIZE;
+			}
+		}
+		if (!stream.avail_in) {
+			wait_on_buffer(bhs[curbh]);
+			if (!buffer_uptodate(bhs[curbh])) {
+				*errp = -EIO;
+				break;
+			}
+			stream.next_in  = bhs[curbh]->b_data +
+						(block_start & bufmask);
+			stream.avail_in = min_t(unsigned, bufsize -
+						(block_start & bufmask),
+						block_size);
+			block_size -= stream.avail_in;
+			block_start = 0;
+		}
+
+		while (stream.avail_out && stream.avail_in) {
+			zerr = zlib_inflate(&stream, Z_SYNC_FLUSH);
+			if (zerr == Z_BUF_ERROR && stream.avail_in == 0)
+				break;
+			if (zerr == Z_STREAM_END)
+				break;
+			if (zerr != Z_OK) {
+				/* EOF, error, or trying to read beyond end of input */
+				if (zerr == Z_MEM_ERROR)
+					*errp = -ENOMEM;
+				else {
+					printk(KERN_DEBUG
+					       "zisofs: zisofs_inflate returned"
+					       " %d, inode = %llu,"
+					       " page idx = %d, bh idx = %d,"
+					       " avail_in = %ld,"
+					       " avail_out = %ld\n",
+					       zerr, inode->i_ino, curpage,
+					       curbh, stream.avail_in,
+					       stream.avail_out);
+					*errp = -EIO;
+				}
+				goto inflate_out;
+			}
+		}
+
+		if (!stream.avail_out) {
+			/* This page completed */
+			if (pages[curpage]) {
+				flush_dcache_page(pages[curpage]);
+				SetPageUptodate(pages[curpage]);
+			}
+			if (stream.next_out != (unsigned char *)zisofs_sink_page) {
+				kunmap_local(stream.next_out);
+				stream.next_out = NULL;
+			}
+			curpage++;
+		}
+		if (!stream.avail_in)
+			curbh++;
+	}
+inflate_out:
+	zlib_inflateEnd(&stream);
+	if (stream.next_out && stream.next_out != (unsigned char *)zisofs_sink_page)
+		kunmap_local(stream.next_out);
+
+z_eio:
+	mutex_unlock(&zisofs_zlib_lock);
+
+b_eio:
+	for (i = 0; i < haveblocks; i++)
+		brelse(bhs[i]);
+	kfree(bhs);
+	return stream.total_out;
+}
+
+/*
+ * Uncompress data so that pages[full_page] is fully uptodate and possibly
+ * fills in other pages if we have data for them.
+ */
+static int zisofs_fill_pages(struct inode *inode, int full_page, int pcount,
+			     struct page **pages)
+{
+	loff_t start_off, end_off;
+	loff_t block_start, block_end;
+	unsigned int header_size = ISOFS_I(inode)->i_format_parm[0];
+	unsigned int zisofs_block_shift = ISOFS_I(inode)->i_format_parm[1];
+	unsigned int blockptr;
+	loff_t poffset = 0;
+	blkcnt_t cstart_block, cend_block;
+	struct buffer_head *bh;
+	unsigned int blkbits = ISOFS_BUFFER_BITS(inode);
+	unsigned int blksize = 1 << blkbits;
+	int err;
+	loff_t ret;
+
+	BUG_ON(!pages[full_page]);
+
+	/*
+	 * We want to read at least 'full_page' page. Because we have to
+	 * uncompress the whole compression block anyway, fill the surrounding
+	 * pages with the data we have anyway...
+	 */
+	start_off = page_offset(pages[full_page]);
+	end_off = min_t(loff_t, start_off + PAGE_SIZE, inode->i_size);
+
+	cstart_block = start_off >> zisofs_block_shift;
+	cend_block = (end_off + (1 << zisofs_block_shift) - 1)
+			>> zisofs_block_shift;
+
+	WARN_ON(start_off - (full_page << PAGE_SHIFT) !=
+		((cstart_block << zisofs_block_shift) & PAGE_MASK));
+
+	/* Find the pointer to this specific chunk */
+	/* Note: we're not using isonum_731() here because the data is known aligned */
+	/* Note: header_size is in 32-bit words (4 bytes) */
+	blockptr = (header_size + cstart_block) << 2;
+	bh = isofs_bread(inode, blockptr >> blkbits);
+	if (!bh)
+		return -EIO;
+	block_start = le32_to_cpu(*(__le32 *)
+				(bh->b_data + (blockptr & (blksize - 1))));
+
+	while (cstart_block < cend_block && pcount > 0) {
+		/* Load end of the compressed block in the file */
+		blockptr += 4;
+		/* Traversed to next block? */
+		if (!(blockptr & (blksize - 1))) {
+			brelse(bh);
+
+			bh = isofs_bread(inode, blockptr >> blkbits);
+			if (!bh)
+				return -EIO;
+		}
+		block_end = le32_to_cpu(*(__le32 *)
+				(bh->b_data + (blockptr & (blksize - 1))));
+		if (block_start > block_end) {
+			brelse(bh);
+			return -EIO;
+		}
+		err = 0;
+		ret = zisofs_uncompress_block(inode, block_start, block_end,
+					      pcount, pages, poffset, &err);
+		poffset += ret;
+		pages += poffset >> PAGE_SHIFT;
+		pcount -= poffset >> PAGE_SHIFT;
+		full_page -= poffset >> PAGE_SHIFT;
+		poffset &= ~PAGE_MASK;
+
+		if (err) {
+			brelse(bh);
+			/*
+			 * Did we finish reading the page we really wanted
+			 * to read?
+			 */
+			if (full_page < 0)
+				return 0;
+			return err;
+		}
+
+		block_start = block_end;
+		cstart_block++;
+	}
+
+	if (poffset && *pages) {
+		memzero_page(*pages, poffset, PAGE_SIZE - poffset);
+		SetPageUptodate(*pages);
+	}
+	return 0;
+}
+
+/*
+ * When decompressing, we typically obtain more than one page
+ * per reference.  We inject the additional pages into the page
+ * cache as a form of readahead.
+ */
+static int zisofs_read_folio(struct file *file, struct folio *folio)
+{
+	struct inode *inode = file_inode(file);
+	struct address_space *mapping = inode->i_mapping;
+	int err;
+	int i, pcount, full_page;
+	unsigned int zisofs_block_shift = ISOFS_I(inode)->i_format_parm[1];
+	unsigned int zisofs_pages_per_cblock =
+		PAGE_SHIFT <= zisofs_block_shift ?
+		(1 << (zisofs_block_shift - PAGE_SHIFT)) : 0;
+	struct page **pages;
+	pgoff_t index = folio->index, end_index;
+
+	end_index = (inode->i_size + PAGE_SIZE - 1) >> PAGE_SHIFT;
+	/*
+	 * If this folio is wholly outside i_size we just return zero;
+	 * do_generic_file_read() will handle this for us
+	 */
+	if (index >= end_index) {
+		folio_end_read(folio, true);
+		return 0;
+	}
+
+	if (PAGE_SHIFT <= zisofs_block_shift) {
+		/* We have already been given one page, this is the one
+		   we must do. */
+		full_page = index & (zisofs_pages_per_cblock - 1);
+		pcount = min_t(int, zisofs_pages_per_cblock,
+			end_index - (index & ~(zisofs_pages_per_cblock - 1)));
+		index -= full_page;
+	} else {
+		full_page = 0;
+		pcount = 1;
+	}
+	pages = kzalloc_objs(*pages,
+			     max_t(unsigned int, zisofs_pages_per_cblock, 1));
+	if (!pages) {
+		folio_unlock(folio);
+		return -ENOMEM;
+	}
+	pages[full_page] = &folio->page;
+
+	for (i = 0; i < pcount; i++, index++) {
+		if (i != full_page)
+			pages[i] = grab_cache_page_nowait(mapping, index);
+	}
+
+	err = zisofs_fill_pages(inode, full_page, pcount, pages);
+
+	/* Release any residual pages, do not SetPageUptodate */
+	for (i = 0; i < pcount; i++) {
+		if (pages[i]) {
+			flush_dcache_page(pages[i]);
+			unlock_page(pages[i]);
+			if (i != full_page)
+				put_page(pages[i]);
+		}
+	}			
+
+	/* At this point, err contains 0 or -EIO depending on the "critical" page */
+	kfree(pages);
+	return err;
+}
+
+const struct address_space_operations zisofs_aops = {
+	.read_folio = zisofs_read_folio,
+	/* No bmap operation supported */
+};
+
+int __init zisofs_init(void)
+{
+	zisofs_zlib_workspace = vmalloc(zlib_inflate_workspacesize());
+	if ( !zisofs_zlib_workspace )
+		return -ENOMEM;
+
+	return 0;
+}
+
+void zisofs_cleanup(void)
+{
+	vfree(zisofs_zlib_workspace);
+}

linux-7.2.3/fs/isofs/dir.c

@@ -0,0 +1,303 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  linux/fs/isofs/dir.c
+ *
+ *  (C) 1992, 1993, 1994  Eric Youngdale Modified for ISO 9660 filesystem.
+ *
+ *  (C) 1991  Linus Torvalds - minix filesystem
+ *
+ *  Steve Beynon		       : Missing last directory entries fixed
+ *  (stephen@askone.demon.co.uk)      : 21st June 1996
+ *
+ *  isofs directory handling functions
+ */
+#include <linux/gfp.h>
+#include <linux/filelock.h>
+#include <linux/slab.h>
+#include "isofs.h"
+#include <linux/fileattr.h>
+
+int isofs_name_translate(struct iso_directory_record *de, char *new, struct inode *inode)
+{
+	char * old = de->name;
+	int len = de->name_len[0];
+	int i;
+
+	for (i = 0; i < len; i++) {
+		unsigned char c = old[i];
+		if (!c)
+			break;
+
+		if (c >= 'A' && c <= 'Z')
+			c |= 0x20;	/* lower case */
+
+		/* Drop trailing '.;1' (ISO 9660:1988 7.5.1 requires period) */
+		if (c == '.' && i == len - 3 && old[i + 1] == ';' && old[i + 2] == '1')
+			break;
+
+		/* Drop trailing ';1' */
+		if (c == ';' && i == len - 2 && old[i + 1] == '1')
+			break;
+
+		/* Convert remaining ';' to '.' */
+		/* Also '/' to '.' (broken Acorn-generated ISO9660 images) */
+		if (c == ';' || c == '/')
+			c = '.';
+
+		new[i] = c;
+	}
+	return i;
+}
+
+/* Acorn extensions written by Matthew Wilcox <willy@infradead.org> 1998 */
+int get_acorn_filename(struct iso_directory_record *de,
+			    char *retname, struct inode *inode)
+{
+	int std;
+	unsigned char *chr;
+	int retnamlen = isofs_name_translate(de, retname, inode);
+
+	if (retnamlen == 0)
+		return 0;
+	std = sizeof(struct iso_directory_record) + de->name_len[0];
+	if (std & 1)
+		std++;
+	if (de->length[0] - std != 32)
+		return retnamlen;
+	chr = ((unsigned char *) de) + std;
+	if (strncmp(chr, "ARCHIMEDES", 10))
+		return retnamlen;
+	if ((*retname == '_') && ((chr[19] & 1) == 1))
+		*retname = '!';
+	if (((de->flags[0] & 2) == 0) && (chr[13] == 0xff)
+		&& ((chr[12] & 0xf0) == 0xf0)) {
+		retname[retnamlen] = ',';
+		sprintf(retname+retnamlen+1, "%3.3x",
+			((chr[12] & 0xf) << 8) | chr[11]);
+		retnamlen += 4;
+	}
+	return retnamlen;
+}
+
+/*
+ * This should _really_ be cleaned up some day..
+ */
+static int do_isofs_readdir(struct inode *inode, struct file *file,
+		struct dir_context *ctx,
+		char *tmpname, struct iso_directory_record *tmpde)
+{
+	unsigned long bufsize = ISOFS_BUFFER_SIZE(inode);
+	unsigned char bufbits = ISOFS_BUFFER_BITS(inode);
+	unsigned long block, offset, block_saved, offset_saved;
+	unsigned long inode_number = 0;	/* Quiet GCC */
+	struct buffer_head *bh = NULL;
+	int len;
+	int map;
+	int first_de = 1;
+	char *p = NULL;		/* Quiet GCC */
+	struct iso_directory_record *de;
+	struct isofs_sb_info *sbi = ISOFS_SB(inode->i_sb);
+
+	offset = ctx->pos & (bufsize - 1);
+	block = ctx->pos >> bufbits;
+
+	while (ctx->pos < inode->i_size) {
+		int de_len;
+
+		if (!bh) {
+			bh = isofs_bread(inode, block);
+			if (!bh)
+				return 0;
+		}
+
+		de = (struct iso_directory_record *) (bh->b_data + offset);
+
+		de_len = *(unsigned char *)de;
+
+		/*
+		 * If the length byte is zero, we should move on to the next
+		 * CDROM sector.  If we are at the end of the directory, we
+		 * kick out of the while loop.
+		 */
+
+		if (de_len == 0) {
+			brelse(bh);
+			bh = NULL;
+			ctx->pos = (ctx->pos + ISOFS_BLOCK_SIZE) & ~(ISOFS_BLOCK_SIZE - 1);
+			block = ctx->pos >> bufbits;
+			offset = 0;
+			continue;
+		}
+
+		block_saved = block;
+		offset_saved = offset;
+		offset += de_len;
+
+		/* Make sure we have a full directory entry */
+		if (offset >= bufsize) {
+			int slop = bufsize - offset + de_len;
+			memcpy(tmpde, de, slop);
+			offset &= bufsize - 1;
+			block++;
+			brelse(bh);
+			bh = NULL;
+			if (offset) {
+				bh = isofs_bread(inode, block);
+				if (!bh)
+					return 0;
+				memcpy((void *) tmpde + slop, bh->b_data, offset);
+			}
+			de = tmpde;
+		}
+		/* Basic sanity check, whether name doesn't exceed dir entry */
+		if (de_len < sizeof(struct iso_directory_record) ||
+		    de_len < de->name_len[0] +
+					sizeof(struct iso_directory_record)) {
+			printk(KERN_NOTICE "iso9660: Corrupted directory entry"
+			       " in block %lu of inode %llu\n", block,
+			       inode->i_ino);
+			brelse(bh);
+			return -EIO;
+		}
+
+		if (first_de) {
+			isofs_normalize_block_and_offset(de,
+							&block_saved,
+							&offset_saved);
+			inode_number = isofs_get_ino(block_saved,
+							offset_saved, bufbits);
+		}
+
+		if (de->flags[-sbi->s_high_sierra] & 0x80) {
+			first_de = 0;
+			ctx->pos += de_len;
+			continue;
+		}
+		first_de = 1;
+
+		/* Handle the case of the '.' directory */
+		if (de->name_len[0] == 1 && de->name[0] == 0) {
+			if (!dir_emit_dot(file, ctx))
+				break;
+			ctx->pos += de_len;
+			continue;
+		}
+
+		len = 0;
+
+		/* Handle the case of the '..' directory */
+		if (de->name_len[0] == 1 && de->name[0] == 1) {
+			if (!dir_emit_dotdot(file, ctx))
+				break;
+			ctx->pos += de_len;
+			continue;
+		}
+
+		/* Handle everything else.  Do name translation if there
+		   is no Rock Ridge NM field. */
+
+		/*
+		 * Do not report hidden files if so instructed, or associated
+		 * files unless instructed to do so
+		 */
+		if ((sbi->s_hide && (de->flags[-sbi->s_high_sierra] & 1)) ||
+		    (!sbi->s_showassoc &&
+				(de->flags[-sbi->s_high_sierra] & 4))) {
+			ctx->pos += de_len;
+			continue;
+		}
+
+		map = 1;
+		if (sbi->s_rock) {
+			len = get_rock_ridge_filename(de, tmpname, inode);
+			if (len != 0) {		/* may be -1 */
+				p = tmpname;
+				map = 0;
+			}
+		}
+		if (map) {
+#ifdef CONFIG_JOLIET
+			if (sbi->s_joliet_level) {
+				len = get_joliet_filename(de, tmpname, inode);
+				p = tmpname;
+			} else
+#endif
+			if (sbi->s_mapping == 'a') {
+				len = get_acorn_filename(de, tmpname, inode);
+				p = tmpname;
+			} else
+			if (sbi->s_mapping == 'n') {
+				len = isofs_name_translate(de, tmpname, inode);
+				p = tmpname;
+			} else {
+				p = de->name;
+				len = de->name_len[0];
+			}
+		}
+		if (len > 0) {
+			if (!dir_emit(ctx, p, len, inode_number, DT_UNKNOWN))
+				break;
+		}
+		ctx->pos += de_len;
+	}
+	if (bh)
+		brelse(bh);
+	return 0;
+}
+
+/*
+ * Handle allocation of temporary space for name translation and
+ * handling split directory entries.. The real work is done by
+ * "do_isofs_readdir()".
+ */
+static int isofs_readdir(struct file *file, struct dir_context *ctx)
+{
+	int result;
+	char *tmpname;
+	struct iso_directory_record *tmpde;
+	struct inode *inode = file_inode(file);
+
+	tmpname = kmalloc(PAGE_SIZE, GFP_KERNEL);
+	if (tmpname == NULL)
+		return -ENOMEM;
+
+	tmpde = (struct iso_directory_record *) (tmpname+1024);
+
+	result = do_isofs_readdir(inode, file, ctx, tmpname, tmpde);
+
+	kfree(tmpname);
+	return result;
+}
+
+int isofs_fileattr_get(struct dentry *dentry, struct file_kattr *fa)
+{
+	struct isofs_sb_info *sbi = ISOFS_SB(dentry->d_sb);
+
+	if (sbi->s_check == 'r') {
+		fa->fsx_xflags |= FS_XFLAG_CASEFOLD;
+		fa->flags |= FS_CASEFOLD_FL;
+	}
+	if (!sbi->s_joliet_level && !sbi->s_rock &&
+	    (sbi->s_mapping == 'n' || sbi->s_mapping == 'a'))
+		fa->fsx_xflags |= FS_XFLAG_CASENONPRESERVING;
+	return 0;
+}
+
+const struct file_operations isofs_dir_operations =
+{
+	.llseek = generic_file_llseek,
+	.read = generic_read_dir,
+	.iterate_shared = isofs_readdir,
+	.setlease = generic_setlease,
+};
+
+/*
+ * directories can handle most operations...
+ */
+const struct inode_operations isofs_dir_inode_operations =
+{
+	.lookup = isofs_lookup,
+	.fileattr_get = isofs_fileattr_get,
+};
+
+

linux-7.2.3/fs/isofs/export.c

@@ -0,0 +1,193 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * fs/isofs/export.c
+ *
+ *  (C) 2004  Paul Serice - The new inode scheme requires switching
+ *                          from iget() to iget5_locked() which means
+ *                          the NFS export operations have to be hand
+ *                          coded because the default routines rely on
+ *                          iget().
+ *
+ * The following files are helpful:
+ *
+ *     Documentation/filesystems/nfs/exporting.rst
+ *     fs/exportfs/expfs.c.
+ */
+
+#include "isofs.h"
+
+static struct dentry *
+isofs_export_iget(struct super_block *sb,
+		  unsigned long block,
+		  unsigned long offset,
+		  __u32 generation)
+{
+	struct inode *inode;
+
+	if (block == 0 || block >= ISOFS_SB(sb)->s_nzones)
+		return ERR_PTR(-ESTALE);
+	inode = isofs_iget(sb, block, offset);
+	if (IS_ERR(inode))
+		return ERR_CAST(inode);
+	if (generation && inode->i_generation != generation) {
+		iput(inode);
+		return ERR_PTR(-ESTALE);
+	}
+	return d_obtain_alias(inode);
+}
+
+/* This function is surprisingly simple.  The trick is understanding
+ * that "child" is always a directory. So, to find its parent, you
+ * simply need to find its ".." entry, normalize its block and offset,
+ * and return the underlying inode.  See the comments for
+ * isofs_normalize_block_and_offset(). */
+static struct dentry *isofs_export_get_parent(struct dentry *child)
+{
+	unsigned long parent_block = 0;
+	unsigned long parent_offset = 0;
+	struct inode *child_inode = d_inode(child);
+	struct iso_inode_info *e_child_inode = ISOFS_I(child_inode);
+	struct iso_directory_record *de = NULL;
+	struct buffer_head * bh = NULL;
+	struct dentry *rv = NULL;
+
+	/* "child" must always be a directory. */
+	if (!S_ISDIR(child_inode->i_mode)) {
+		printk(KERN_ERR "isofs: isofs_export_get_parent(): "
+		       "child is not a directory!\n");
+		rv = ERR_PTR(-EACCES);
+		goto out;
+	}
+
+	/* It is an invariant that the directory offset is zero.  If
+	 * it is not zero, it means the directory failed to be
+	 * normalized for some reason. */
+	if (e_child_inode->i_iget5_offset != 0) {
+		printk(KERN_ERR "isofs: isofs_export_get_parent(): "
+		       "child directory not normalized!\n");
+		rv = ERR_PTR(-EACCES);
+		goto out;
+	}
+
+	/* The child inode has been normalized such that its
+	 * i_iget5_block value points to the "." entry.  Fortunately,
+	 * the ".." entry is located in the same block. */
+	parent_block = e_child_inode->i_iget5_block;
+
+	/* Get the block in question. */
+	bh = sb_bread(child_inode->i_sb, parent_block);
+	if (bh == NULL) {
+		rv = ERR_PTR(-EACCES);
+		goto out;
+	}
+
+	/* This is the "." entry. */
+	de = (struct iso_directory_record*)bh->b_data;
+
+	/* The ".." entry is always the second entry. */
+	parent_offset = (unsigned long)isonum_711(de->length);
+	de = (struct iso_directory_record*)(bh->b_data + parent_offset);
+
+	/* Verify it is in fact the ".." entry. */
+	if ((isonum_711(de->name_len) != 1) || (de->name[0] != 1)) {
+		printk(KERN_ERR "isofs: Unable to find the \"..\" "
+		       "directory for NFS.\n");
+		rv = ERR_PTR(-EACCES);
+		goto out;
+	}
+
+	/* Normalize */
+	isofs_normalize_block_and_offset(de, &parent_block, &parent_offset);
+
+	rv = d_obtain_alias(isofs_iget(child_inode->i_sb, parent_block,
+				     parent_offset));
+ out:
+	if (bh)
+		brelse(bh);
+	return rv;
+}
+
+static int
+isofs_export_encode_fh(struct inode *inode,
+		       __u32 *fh32,
+		       int *max_len,
+		       struct inode *parent)
+{
+	struct iso_inode_info * ei = ISOFS_I(inode);
+	int len = *max_len;
+	int type = 1;
+	__u16 *fh16 = (__u16*)fh32;
+
+	/*
+	 * WARNING: max_len is 5 for NFSv2.  Because of this
+	 * limitation, we use the lower 16 bits of fh32[1] to hold the
+	 * offset of the inode and the upper 16 bits of fh32[1] to
+	 * hold the offset of the parent.
+	 */
+	if (parent && (len < 5)) {
+		*max_len = 5;
+		return FILEID_INVALID;
+	} else if (len < 3) {
+		*max_len = 3;
+		return FILEID_INVALID;
+	}
+
+	len = 3;
+	fh32[0] = ei->i_iget5_block;
+ 	fh16[2] = (__u16)ei->i_iget5_offset;  /* fh16 [sic] */
+	fh16[3] = 0;  /* avoid leaking uninitialized data */
+	fh32[2] = inode->i_generation;
+	if (parent) {
+		struct iso_inode_info *eparent;
+		eparent = ISOFS_I(parent);
+		fh32[3] = eparent->i_iget5_block;
+		fh16[3] = (__u16)eparent->i_iget5_offset;  /* fh16 [sic] */
+		fh32[4] = parent->i_generation;
+		len = 5;
+		type = 2;
+	}
+	*max_len = len;
+	return type;
+}
+
+struct isofs_fid {
+	u32 block;
+	u16 offset;
+	u16 parent_offset;
+	u32 generation;
+	u32 parent_block;
+	u32 parent_generation;
+};
+
+static struct dentry *isofs_fh_to_dentry(struct super_block *sb,
+	struct fid *fid, int fh_len, int fh_type)
+{
+	struct isofs_fid *ifid = (struct isofs_fid *)fid;
+
+	if (fh_len < 3 || fh_type > 2)
+		return NULL;
+
+	return isofs_export_iget(sb, ifid->block, ifid->offset,
+			ifid->generation);
+}
+
+static struct dentry *isofs_fh_to_parent(struct super_block *sb,
+		struct fid *fid, int fh_len, int fh_type)
+{
+	struct isofs_fid *ifid = (struct isofs_fid *)fid;
+
+	if (fh_len < 2 || fh_type != 2)
+		return NULL;
+
+	return isofs_export_iget(sb,
+			fh_len > 3 ? ifid->parent_block : 0,
+			ifid->parent_offset,
+			fh_len > 4 ? ifid->parent_generation : 0);
+}
+
+const struct export_operations isofs_export_ops = {
+	.encode_fh	= isofs_export_encode_fh,
+	.fh_to_dentry	= isofs_fh_to_dentry,
+	.fh_to_parent	= isofs_fh_to_parent,
+	.get_parent     = isofs_export_get_parent,
+};

linux-7.2.3/fs/isofs/isofs.h

@@ -0,0 +1,206 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#include <linux/fs.h>
+#include <linux/buffer_head.h>
+#include <linux/exportfs.h>
+#include <linux/iso_fs.h>
+#include <linux/unaligned.h>
+
+enum isofs_file_format {
+	isofs_file_normal = 0,
+	isofs_file_sparse = 1,
+	isofs_file_compressed = 2,
+};
+	
+/*
+ * iso fs inode data in memory
+ */
+struct iso_inode_info {
+	unsigned long i_iget5_block;
+	unsigned long i_iget5_offset;
+	unsigned int i_first_extent;
+	unsigned char i_file_format;
+	unsigned char i_format_parm[3];
+	unsigned long i_next_section_block;
+	unsigned long i_next_section_offset;
+	off_t i_section_size;
+	struct inode vfs_inode;
+};
+
+/*
+ * iso9660 super-block data in memory
+ */
+struct isofs_sb_info {
+	unsigned long s_ninodes;
+	unsigned long s_nzones;
+	unsigned long s_firstdatazone;
+	unsigned long s_log_zone_size;
+	unsigned long s_max_size;
+	
+	int           s_rock_offset; /* offset of SUSP fields within SU area */
+	s32           s_sbsector;
+	unsigned char s_joliet_level;
+	unsigned char s_mapping;
+	unsigned char s_check;
+	unsigned char s_session;
+	unsigned int  s_high_sierra:1;
+	unsigned int  s_rock:2;
+	unsigned int  s_cruft:1; /* Broken disks with high byte of length
+				  * containing junk */
+	unsigned int  s_nocompress:1;
+	unsigned int  s_hide:1;
+	unsigned int  s_showassoc:1;
+	unsigned int  s_overriderockperm:1;
+	unsigned int  s_uid_set:1;
+	unsigned int  s_gid_set:1;
+
+	umode_t s_fmode;
+	umode_t s_dmode;
+	kgid_t s_gid;
+	kuid_t s_uid;
+	struct nls_table *s_nls_iocharset; /* Native language support table */
+};
+
+#define ISOFS_INVALID_MODE ((umode_t) -1)
+
+static inline struct isofs_sb_info *ISOFS_SB(struct super_block *sb)
+{
+	return sb->s_fs_info;
+}
+
+static inline struct iso_inode_info *ISOFS_I(struct inode *inode)
+{
+	return container_of(inode, struct iso_inode_info, vfs_inode);
+}
+
+static inline int isonum_711(u8 *p)
+{
+	return *p;
+}
+static inline int isonum_712(s8 *p)
+{
+	return *p;
+}
+static inline unsigned int isonum_721(u8 *p)
+{
+	return get_unaligned_le16(p);
+}
+static inline unsigned int isonum_722(u8 *p)
+{
+	return get_unaligned_be16(p);
+}
+static inline unsigned int isonum_723(u8 *p)
+{
+	/* Ignore bigendian datum due to broken mastering programs */
+	return get_unaligned_le16(p);
+}
+static inline unsigned int isonum_731(u8 *p)
+{
+	return get_unaligned_le32(p);
+}
+static inline unsigned int isonum_732(u8 *p)
+{
+	return get_unaligned_be32(p);
+}
+static inline unsigned int isonum_733(u8 *p)
+{
+	/* Ignore bigendian datum due to broken mastering programs */
+	return get_unaligned_le32(p);
+}
+#define ISO_DATE_HIGH_SIERRA (1 << 0)
+#define ISO_DATE_LONG_FORM (1 << 1)
+struct timespec64 iso_date(u8 *p, int flags);
+
+struct inode;		/* To make gcc happy */
+
+extern int parse_rock_ridge_inode(struct iso_directory_record *, struct inode *, int relocated);
+extern int get_rock_ridge_filename(struct iso_directory_record *, char *, struct inode *);
+extern int isofs_name_translate(struct iso_directory_record *, char *, struct inode *);
+
+int get_joliet_filename(struct iso_directory_record *, unsigned char *, struct inode *);
+int get_acorn_filename(struct iso_directory_record *, char *, struct inode *);
+
+extern struct dentry *isofs_lookup(struct inode *, struct dentry *, unsigned int flags);
+extern struct buffer_head *isofs_bread(struct inode *, sector_t);
+extern int isofs_get_blocks(struct inode *, sector_t, struct buffer_head **, unsigned long);
+
+struct inode *__isofs_iget(struct super_block *sb,
+			   unsigned long block,
+			   unsigned long offset,
+			   int relocated);
+
+static inline struct inode *isofs_iget(struct super_block *sb,
+				       unsigned long block,
+				       unsigned long offset)
+{
+	return __isofs_iget(sb, block, offset, 0);
+}
+
+static inline struct inode *isofs_iget_reloc(struct super_block *sb,
+					     unsigned long block,
+					     unsigned long offset)
+{
+	return __isofs_iget(sb, block, offset, 1);
+}
+
+/* Because the inode number is no longer relevant to finding the
+ * underlying meta-data for an inode, we are free to choose a more
+ * convenient 32-bit number as the inode number.  The inode numbering
+ * scheme was recommended by Sergey Vlasov and Eric Lammerts. */
+static inline unsigned long isofs_get_ino(unsigned long block,
+					  unsigned long offset,
+					  unsigned long bufbits)
+{
+	return (block << (bufbits - 5)) | (offset >> 5);
+}
+
+/* Every directory can have many redundant directory entries scattered
+ * throughout the directory tree.  First there is the directory entry
+ * with the name of the directory stored in the parent directory.
+ * Then, there is the "." directory entry stored in the directory
+ * itself.  Finally, there are possibly many ".." directory entries
+ * stored in all the subdirectories.
+ *
+ * In order for the NFS get_parent() method to work and for the
+ * general consistency of the dcache, we need to make sure the
+ * "i_iget5_block" and "i_iget5_offset" all point to exactly one of
+ * the many redundant entries for each directory.  We normalize the
+ * block and offset by always making them point to the "."  directory.
+ *
+ * Notice that we do not use the entry for the directory with the name
+ * that is located in the parent directory.  Even though choosing this
+ * first directory is more natural, it is much easier to find the "."
+ * entry in the NFS get_parent() method because it is implicitly
+ * encoded in the "extent + ext_attr_length" fields of _all_ the
+ * redundant entries for the directory.  Thus, it can always be
+ * reached regardless of which directory entry you have in hand.
+ *
+ * This works because the "." entry is simply the first directory
+ * record when you start reading the file that holds all the directory
+ * records, and this file starts at "extent + ext_attr_length" blocks.
+ * Because the "." entry is always the first entry listed in the
+ * directories file, the normalized "offset" value is always 0.
+ *
+ * You should pass the directory entry in "de".  On return, "block"
+ * and "offset" will hold normalized values.  Only directories are
+ * affected making it safe to call even for non-directory file
+ * types. */
+static inline void
+isofs_normalize_block_and_offset(struct iso_directory_record* de,
+				 unsigned long *block,
+				 unsigned long *offset)
+{
+	/* Only directories are normalized. */
+	if (de->flags[0] & 2) {
+		*offset = 0;
+		*block = (unsigned long)isonum_733(de->extent)
+			+ (unsigned long)isonum_711(de->ext_attr_length);
+	}
+}
+
+struct file_kattr;
+int isofs_fileattr_get(struct dentry *dentry, struct file_kattr *fa);
+
+extern const struct inode_operations isofs_dir_inode_operations;
+extern const struct file_operations isofs_dir_operations;
+extern const struct address_space_operations isofs_symlink_aops;
+extern const struct export_operations isofs_export_ops;

linux-7.2.3/fs/isofs/joliet.c

@@ -0,0 +1,68 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  linux/fs/isofs/joliet.c
+ *
+ *  (C) 1996 Gordon Chaffee
+ *
+ *  Joliet: Microsoft's Unicode extensions to iso9660
+ */
+
+#include <linux/types.h>
+#include <linux/nls.h>
+#include "isofs.h"
+
+/*
+ * Convert Unicode 16 to UTF-8 or ASCII.
+ */
+static int
+uni16_to_x8(unsigned char *ascii, __be16 *uni, int len, struct nls_table *nls)
+{
+	__be16 *ip, ch;
+	unsigned char *op;
+
+	ip = uni;
+	op = ascii;
+
+	while ((ch = get_unaligned(ip)) && len) {
+		int llen;
+		llen = nls->uni2char(be16_to_cpu(ch), op, NLS_MAX_CHARSET_SIZE);
+		if (llen > 0)
+			op += llen;
+		else
+			*op++ = '?';
+		ip++;
+
+		len--;
+	}
+	*op = 0;
+	return (op - ascii);
+}
+
+int
+get_joliet_filename(struct iso_directory_record * de, unsigned char *outname, struct inode * inode)
+{
+	struct nls_table *nls;
+	unsigned char len = 0;
+
+	nls = ISOFS_SB(inode->i_sb)->s_nls_iocharset;
+
+	if (!nls) {
+		len = utf16s_to_utf8s((const wchar_t *) de->name,
+				de->name_len[0] >> 1, UTF16_BIG_ENDIAN,
+				outname, PAGE_SIZE);
+	} else {
+		len = uni16_to_x8(outname, (__be16 *) de->name,
+				de->name_len[0] >> 1, nls);
+	}
+	if ((len > 2) && (outname[len-2] == ';') && (outname[len-1] == '1'))
+		len -= 2;
+
+	/*
+	 * Windows doesn't like periods at the end of a name,
+	 * so neither do we
+	 */
+	while (len >= 2 && (outname[len-1] == '.'))
+		len--;
+
+	return len;
+}

linux-7.2.3/fs/isofs/namei.c

@@ -0,0 +1,167 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  linux/fs/isofs/namei.c
+ *
+ *  (C) 1992  Eric Youngdale Modified for ISO 9660 filesystem.
+ *
+ *  (C) 1991  Linus Torvalds - minix filesystem
+ */
+
+#include <linux/gfp.h>
+#include "isofs.h"
+
+static int
+isofs_cmp(struct dentry *dentry, const char *compare, int dlen)
+{
+	if (likely(!dentry->d_op))
+		return dentry->d_name.len != dlen || memcmp(dentry->d_name.name, compare, dlen);
+	return dentry->d_op->d_compare(NULL, dentry->d_name.len, dentry->d_name.name,
+				       &QSTR_LEN(compare, dlen));
+}
+
+/*
+ *	isofs_find_entry()
+ *
+ * finds an entry in the specified directory with the wanted name. It
+ * returns the inode number of the found entry, or 0 on error.
+ */
+static unsigned long
+isofs_find_entry(struct inode *dir, struct dentry *dentry,
+	unsigned long *block_rv, unsigned long *offset_rv,
+	char *tmpname, struct iso_directory_record *tmpde)
+{
+	unsigned long bufsize = ISOFS_BUFFER_SIZE(dir);
+	unsigned char bufbits = ISOFS_BUFFER_BITS(dir);
+	unsigned long block, f_pos, offset, block_saved, offset_saved;
+	struct buffer_head *bh = NULL;
+	struct isofs_sb_info *sbi = ISOFS_SB(dir->i_sb);
+
+	if (!ISOFS_I(dir)->i_first_extent)
+		return 0;
+
+	f_pos = 0;
+	offset = 0;
+	block = 0;
+
+	while (f_pos < dir->i_size) {
+		struct iso_directory_record *de;
+		int de_len, match, i, dlen;
+		char *dpnt;
+
+		if (!bh) {
+			bh = isofs_bread(dir, block);
+			if (!bh)
+				return 0;
+		}
+
+		de = (struct iso_directory_record *) (bh->b_data + offset);
+
+		de_len = *(unsigned char *) de;
+		if (!de_len) {
+			brelse(bh);
+			bh = NULL;
+			f_pos = (f_pos + ISOFS_BLOCK_SIZE) & ~(ISOFS_BLOCK_SIZE - 1);
+			block = f_pos >> bufbits;
+			offset = 0;
+			continue;
+		}
+
+		block_saved = bh->b_blocknr;
+		offset_saved = offset;
+		offset += de_len;
+		f_pos += de_len;
+
+		/* Make sure we have a full directory entry */
+		if (offset >= bufsize) {
+			int slop = bufsize - offset + de_len;
+			memcpy(tmpde, de, slop);
+			offset &= bufsize - 1;
+			block++;
+			brelse(bh);
+			bh = NULL;
+			if (offset) {
+				bh = isofs_bread(dir, block);
+				if (!bh)
+					return 0;
+				memcpy((void *) tmpde + slop, bh->b_data, offset);
+			}
+			de = tmpde;
+		}
+
+		dlen = de->name_len[0];
+		dpnt = de->name;
+		/* Basic sanity check, whether name doesn't exceed dir entry */
+		if (de_len < dlen + sizeof(struct iso_directory_record)) {
+			printk(KERN_NOTICE "iso9660: Corrupted directory entry"
+			       " in block %lu of inode %llu\n", block,
+			       dir->i_ino);
+			brelse(bh);
+			return 0;
+		}
+
+		if (sbi->s_rock &&
+		    ((i = get_rock_ridge_filename(de, tmpname, dir)))) {
+			dlen = i;	/* possibly -1 */
+			dpnt = tmpname;
+#ifdef CONFIG_JOLIET
+		} else if (sbi->s_joliet_level) {
+			dlen = get_joliet_filename(de, tmpname, dir);
+			dpnt = tmpname;
+#endif
+		} else if (sbi->s_mapping == 'a') {
+			dlen = get_acorn_filename(de, tmpname, dir);
+			dpnt = tmpname;
+		} else if (sbi->s_mapping == 'n') {
+			dlen = isofs_name_translate(de, tmpname, dir);
+			dpnt = tmpname;
+		}
+
+		/*
+		 * Skip hidden or associated files unless hide or showassoc,
+		 * respectively, is set
+		 */
+		match = 0;
+		if (dlen > 0 &&
+			(!sbi->s_hide ||
+				(!(de->flags[-sbi->s_high_sierra] & 1))) &&
+			(sbi->s_showassoc ||
+				(!(de->flags[-sbi->s_high_sierra] & 4)))) {
+			if (dpnt && (dlen > 1 || dpnt[0] > 1))
+				match = (isofs_cmp(dentry, dpnt, dlen) == 0);
+		}
+		if (match) {
+			isofs_normalize_block_and_offset(de,
+							 &block_saved,
+							 &offset_saved);
+			*block_rv = block_saved;
+			*offset_rv = offset_saved;
+			brelse(bh);
+			return 1;
+		}
+	}
+	brelse(bh);
+	return 0;
+}
+
+struct dentry *isofs_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
+{
+	int found;
+	unsigned long block;
+	unsigned long offset;
+	struct inode *inode;
+	struct page *page;
+
+	page = alloc_page(GFP_USER);
+	if (!page)
+		return ERR_PTR(-ENOMEM);
+
+	found = isofs_find_entry(dir, dentry,
+				&block, &offset,
+				page_address(page),
+				1024 + page_address(page));
+	__free_page(page);
+
+	inode = found ? isofs_iget(dir->i_sb, block, offset) : NULL;
+
+	return d_splice_alias(inode, dentry);
+}

linux-7.2.3/fs/isofs/rock.c

@@ -0,0 +1,830 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  linux/fs/isofs/rock.c
+ *
+ *  (C) 1992, 1993  Eric Youngdale
+ *
+ *  Rock Ridge Extensions to iso9660
+ */
+
+#include <linux/slab.h>
+#include <linux/pagemap.h>
+
+#include "isofs.h"
+#include "rock.h"
+
+/*
+ * These functions are designed to read the system areas of a directory record
+ * and extract relevant information.  There are different functions provided
+ * depending upon what information we need at the time.  One function fills
+ * out an inode structure, a second one extracts a filename, a third one
+ * returns a symbolic link name, and a fourth one returns the extent number
+ * for the file.
+ */
+
+#define SIG(A,B) ((A) | ((B) << 8))	/* isonum_721() */
+
+struct rock_state {
+	void *buffer;
+	unsigned char *chr;
+	int len;
+	int cont_size;
+	int cont_extent;
+	int cont_offset;
+	int cont_loops;
+	struct inode *inode;
+};
+
+/*
+ * This is a way of ensuring that we have something in the system
+ * use fields that is compatible with Rock Ridge.  Return zero on success.
+ */
+
+static int check_sp(struct rock_ridge *rr, struct inode *inode)
+{
+	if (rr->u.SP.magic[0] != 0xbe)
+		return -1;
+	if (rr->u.SP.magic[1] != 0xef)
+		return -1;
+	ISOFS_SB(inode->i_sb)->s_rock_offset = rr->u.SP.skip;
+	return 0;
+}
+
+static void setup_rock_ridge(struct iso_directory_record *de,
+			struct inode *inode, struct rock_state *rs)
+{
+	rs->len = sizeof(struct iso_directory_record) + de->name_len[0];
+	if (rs->len & 1)
+		(rs->len)++;
+	rs->chr = (unsigned char *)de + rs->len;
+	rs->len = *((unsigned char *)de) - rs->len;
+	if (rs->len < 0)
+		rs->len = 0;
+
+	if (ISOFS_SB(inode->i_sb)->s_rock_offset != -1) {
+		rs->len -= ISOFS_SB(inode->i_sb)->s_rock_offset;
+		rs->chr += ISOFS_SB(inode->i_sb)->s_rock_offset;
+		if (rs->len < 0)
+			rs->len = 0;
+	}
+}
+
+static void init_rock_state(struct rock_state *rs, struct inode *inode)
+{
+	memset(rs, 0, sizeof(*rs));
+	rs->inode = inode;
+}
+
+/* Maximum number of Rock Ridge continuation entries */
+#define RR_MAX_CE_ENTRIES 32
+
+/*
+ * Returns 0 if the caller should continue scanning, 1 if the scan must end
+ * and -ve on error.
+ */
+static int rock_continue(struct rock_state *rs)
+{
+	int ret = 1;
+	int blocksize = 1 << rs->inode->i_blkbits;
+	const int min_de_size = offsetof(struct rock_ridge, u);
+
+	kfree(rs->buffer);
+	rs->buffer = NULL;
+
+	if ((unsigned)rs->cont_offset > blocksize - min_de_size ||
+	    (unsigned)rs->cont_size > blocksize ||
+	    (unsigned)(rs->cont_offset + rs->cont_size) > blocksize) {
+		printk(KERN_NOTICE "rock: corrupted directory entry. "
+			"extent=%d, offset=%d, size=%d\n",
+			rs->cont_extent, rs->cont_offset, rs->cont_size);
+		ret = -EIO;
+		goto out;
+	}
+
+	if ((unsigned)rs->cont_extent >= ISOFS_SB(rs->inode->i_sb)->s_nzones) {
+		printk(KERN_NOTICE "rock: corrupted directory entry. "
+			"extent=%u out of volume (nzones=%lu)\n",
+			(unsigned)rs->cont_extent,
+			ISOFS_SB(rs->inode->i_sb)->s_nzones);
+		ret = -EIO;
+		goto out;
+	}
+
+	if (rs->cont_extent) {
+		struct buffer_head *bh;
+
+		rs->buffer = kmalloc(rs->cont_size, GFP_KERNEL);
+		if (!rs->buffer) {
+			ret = -ENOMEM;
+			goto out;
+		}
+		ret = -EIO;
+		if (++rs->cont_loops >= RR_MAX_CE_ENTRIES)
+			goto out;
+		bh = sb_bread(rs->inode->i_sb, rs->cont_extent);
+		if (bh) {
+			memcpy(rs->buffer, bh->b_data + rs->cont_offset,
+					rs->cont_size);
+			put_bh(bh);
+			rs->chr = rs->buffer;
+			rs->len = rs->cont_size;
+			rs->cont_extent = 0;
+			rs->cont_size = 0;
+			rs->cont_offset = 0;
+			return 0;
+		}
+		printk("Unable to read rock-ridge attributes\n");
+	}
+out:
+	kfree(rs->buffer);
+	rs->buffer = NULL;
+	return ret;
+}
+
+/*
+ * We think there's a record of type `sig' at rs->chr.  Parse the signature
+ * and make sure that there's really room for a record of that type.
+ */
+static int rock_check_overflow(struct rock_state *rs, int sig)
+{
+	int len;
+
+	switch (sig) {
+	case SIG('S', 'P'):
+		len = sizeof(struct SU_SP_s);
+		break;
+	case SIG('C', 'E'):
+		len = sizeof(struct SU_CE_s);
+		break;
+	case SIG('E', 'R'):
+		len = sizeof(struct SU_ER_s);
+		break;
+	case SIG('R', 'R'):
+		len = sizeof(struct RR_RR_s);
+		break;
+	case SIG('P', 'X'):
+		len = sizeof(struct RR_PX_s);
+		break;
+	case SIG('P', 'N'):
+		len = sizeof(struct RR_PN_s);
+		break;
+	case SIG('S', 'L'):
+		len = sizeof(struct RR_SL_s);
+		break;
+	case SIG('N', 'M'):
+		len = sizeof(struct RR_NM_s);
+		break;
+	case SIG('C', 'L'):
+		len = sizeof(struct RR_CL_s);
+		break;
+	case SIG('P', 'L'):
+		len = sizeof(struct RR_PL_s);
+		break;
+	case SIG('T', 'F'):
+		len = sizeof(struct RR_TF_s);
+		break;
+	case SIG('Z', 'F'):
+		len = sizeof(struct RR_ZF_s);
+		break;
+	default:
+		len = 0;
+		break;
+	}
+	len += offsetof(struct rock_ridge, u);
+	if (len > rs->len) {
+		printk(KERN_NOTICE "rock: directory entry would overflow "
+				"storage\n");
+		printk(KERN_NOTICE "rock: sig=0x%02x, size=%d, remaining=%d\n",
+				sig, len, rs->len);
+		return -EIO;
+	}
+	return 0;
+}
+
+/*
+ * return length of name field; 0: not found, -1: to be ignored
+ */
+int get_rock_ridge_filename(struct iso_directory_record *de,
+			    char *retname, struct inode *inode)
+{
+	struct rock_state rs;
+	struct rock_ridge *rr;
+	int sig;
+	int retnamlen = 0;
+	int truncate = 0;
+	int ret = 0;
+	char *p;
+	int len;
+
+	if (!ISOFS_SB(inode->i_sb)->s_rock)
+		return 0;
+	*retname = 0;
+
+	init_rock_state(&rs, inode);
+	setup_rock_ridge(de, inode, &rs);
+repeat:
+
+	while (rs.len > 2) { /* There may be one byte for padding somewhere */
+		rr = (struct rock_ridge *)rs.chr;
+		/*
+		 * Ignore rock ridge info if rr->len is out of range, but
+		 * don't return -EIO because that would make the file
+		 * invisible.
+		 */
+		if (rr->len < 3)
+			goto out;	/* Something got screwed up here */
+		sig = isonum_721(rs.chr);
+		if (rock_check_overflow(&rs, sig))
+			goto eio;
+		rs.chr += rr->len;
+		rs.len -= rr->len;
+		/*
+		 * As above, just ignore the rock ridge info if rr->len
+		 * is bogus.
+		 */
+		if (rs.len < 0)
+			goto out;	/* Something got screwed up here */
+
+		switch (sig) {
+		case SIG('R', 'R'):
+			if ((rr->u.RR.flags[0] & RR_NM) == 0)
+				goto out;
+			break;
+		case SIG('S', 'P'):
+			if (check_sp(rr, inode))
+				goto out;
+			break;
+		case SIG('C', 'E'):
+			rs.cont_extent = isonum_733(rr->u.CE.extent);
+			rs.cont_offset = isonum_733(rr->u.CE.offset);
+			rs.cont_size = isonum_733(rr->u.CE.size);
+			break;
+		case SIG('N', 'M'):
+			if (truncate)
+				break;
+			if (rr->len < 5)
+				break;
+			/*
+			 * If the flags are 2 or 4, this indicates '.' or '..'.
+			 * We don't want to do anything with this, because it
+			 * screws up the code that calls us.  We don't really
+			 * care anyways, since we can just use the non-RR
+			 * name.
+			 */
+			if (rr->u.NM.flags & 6)
+				break;
+
+			if (rr->u.NM.flags & ~1) {
+				printk("Unsupported NM flag settings (%d)\n",
+					rr->u.NM.flags);
+				break;
+			}
+			len = rr->len - 5;
+			if (retnamlen + len > NAME_MAX) {
+				truncate = 1;
+				break;
+			}
+			p = memchr(rr->u.NM.name, '\0', len);
+			if (unlikely(p))
+				len = p - rr->u.NM.name;
+			memcpy(retname + retnamlen, rr->u.NM.name, len);
+			retnamlen += len;
+			retname[retnamlen] = '\0';
+			break;
+		case SIG('R', 'E'):
+			kfree(rs.buffer);
+			return -1;
+		default:
+			break;
+		}
+	}
+	ret = rock_continue(&rs);
+	if (ret == 0)
+		goto repeat;
+	if (ret == 1)
+		return retnamlen; /* If 0, this file did not have a NM field */
+out:
+	kfree(rs.buffer);
+	return ret;
+eio:
+	ret = -EIO;
+	goto out;
+}
+
+#define RR_REGARD_XA 1
+#define RR_RELOC_DE 2
+
+static int
+parse_rock_ridge_inode_internal(struct iso_directory_record *de,
+				struct inode *inode, int flags)
+{
+	int symlink_len = 0;
+	int cnt, sig;
+	unsigned int reloc_block;
+	struct inode *reloc;
+	struct rock_ridge *rr;
+	int rootflag;
+	struct rock_state rs;
+	int ret = 0;
+
+	if (!ISOFS_SB(inode->i_sb)->s_rock)
+		return 0;
+
+	init_rock_state(&rs, inode);
+	setup_rock_ridge(de, inode, &rs);
+	if (flags & RR_REGARD_XA) {
+		rs.chr += 14;
+		rs.len -= 14;
+		if (rs.len < 0)
+			rs.len = 0;
+	}
+
+repeat:
+	while (rs.len > 2) { /* There may be one byte for padding somewhere */
+		rr = (struct rock_ridge *)rs.chr;
+		/*
+		 * Ignore rock ridge info if rr->len is out of range, but
+		 * don't return -EIO because that would make the file
+		 * invisible.
+		 */
+		if (rr->len < 3)
+			goto out;	/* Something got screwed up here */
+		sig = isonum_721(rs.chr);
+		if (rock_check_overflow(&rs, sig))
+			goto eio;
+		rs.chr += rr->len;
+		rs.len -= rr->len;
+		/*
+		 * As above, just ignore the rock ridge info if rr->len
+		 * is bogus.
+		 */
+		if (rs.len < 0)
+			goto out;	/* Something got screwed up here */
+
+		switch (sig) {
+#ifndef CONFIG_ZISOFS		/* No flag for SF or ZF */
+		case SIG('R', 'R'):
+			if ((rr->u.RR.flags[0] &
+			     (RR_PX | RR_TF | RR_SL | RR_CL)) == 0)
+				goto out;
+			break;
+#endif
+		case SIG('S', 'P'):
+			if (check_sp(rr, inode))
+				goto out;
+			break;
+		case SIG('C', 'E'):
+			rs.cont_extent = isonum_733(rr->u.CE.extent);
+			rs.cont_offset = isonum_733(rr->u.CE.offset);
+			rs.cont_size = isonum_733(rr->u.CE.size);
+			break;
+		case SIG('E', 'R'):
+			/* Invalid length of ER tag id? */
+			if (rr->u.ER.len_id + offsetof(struct rock_ridge, u.ER.data) > rr->len)
+				goto out;
+			ISOFS_SB(inode->i_sb)->s_rock = 1;
+			printk(KERN_DEBUG "ISO 9660 Extensions: ");
+			{
+				int p;
+				for (p = 0; p < rr->u.ER.len_id; p++)
+					printk(KERN_CONT "%c", rr->u.ER.data[p]);
+			}
+			printk(KERN_CONT "\n");
+			break;
+		case SIG('P', 'X'):
+			inode->i_mode = isonum_733(rr->u.PX.mode);
+			set_nlink(inode, isonum_733(rr->u.PX.n_links));
+			i_uid_write(inode, isonum_733(rr->u.PX.uid));
+			i_gid_write(inode, isonum_733(rr->u.PX.gid));
+			break;
+		case SIG('P', 'N'):
+			{
+				int high, low;
+				high = isonum_733(rr->u.PN.dev_high);
+				low = isonum_733(rr->u.PN.dev_low);
+				/*
+				 * The Rock Ridge standard specifies that if
+				 * sizeof(dev_t) <= 4, then the high field is
+				 * unused, and the device number is completely
+				 * stored in the low field.  Some writers may
+				 * ignore this subtlety,
+				 * and as a result we test to see if the entire
+				 * device number is
+				 * stored in the low field, and use that.
+				 */
+				if ((low & ~0xff) && high == 0) {
+					inode->i_rdev =
+					    MKDEV(low >> 8, low & 0xff);
+				} else {
+					inode->i_rdev =
+					    MKDEV(high, low);
+				}
+			}
+			break;
+		case SIG('T', 'F'): {
+			int flags, size, slen;
+
+			flags = rr->u.TF.flags & TF_LONG_FORM ? ISO_DATE_LONG_FORM : 0;
+			size = rr->u.TF.flags & TF_LONG_FORM ? 17 : 7;
+			slen = rr->len - 5;
+			/*
+			 * Some RRIP writers incorrectly place ctime in the
+			 * TF_CREATE field. Try to handle this correctly for
+			 * either case.
+			 */
+			/* Rock ridge never appears on a High Sierra disk */
+			cnt = 0;
+			if ((rr->u.TF.flags & TF_CREATE) && size <= slen) {
+				inode_set_ctime_to_ts(inode,
+						iso_date(rr->u.TF.data + size * cnt++, flags));
+				slen -= size;
+			}
+			if ((rr->u.TF.flags & TF_MODIFY) && size <= slen) {
+				inode_set_mtime_to_ts(inode,
+						iso_date(rr->u.TF.data + size * cnt++, flags));
+				slen -= size;
+			}
+			if ((rr->u.TF.flags & TF_ACCESS) && size <= slen) {
+				inode_set_atime_to_ts(inode,
+						iso_date(rr->u.TF.data + size * cnt++, flags));
+				slen -= size;
+			}
+			if ((rr->u.TF.flags & TF_ATTRIBUTES) && size <= slen) {
+				inode_set_ctime_to_ts(inode,
+						iso_date(rr->u.TF.data + size * cnt++, flags));
+				slen -= size;
+			}
+			break;
+		}
+		case SIG('S', 'L'):
+			{
+				int slen;
+				struct SL_component *slp;
+				struct SL_component *oldslp;
+				slen = rr->len - 5;
+				slp = &rr->u.SL.link;
+				inode->i_size = symlink_len;
+				while (slen > 1) {
+					rootflag = 0;
+					/* keep the component within the SL record */
+					if (slp->len + 2 > slen)
+						goto eio;
+					switch (slp->flags & ~1) {
+					case 0:
+						inode->i_size +=
+						    slp->len;
+						break;
+					case 2:
+						inode->i_size += 1;
+						break;
+					case 4:
+						inode->i_size += 2;
+						break;
+					case 8:
+						rootflag = 1;
+						inode->i_size += 1;
+						break;
+					default:
+						printk("Symlink component flag "
+							"not implemented\n");
+					}
+					slen -= slp->len + 2;
+					oldslp = slp;
+					slp = (struct SL_component *)
+						(((char *)slp) + slp->len + 2);
+
+					if (slen < 2) {
+						if (((rr->u.SL.
+						      flags & 1) != 0)
+						    &&
+						    ((oldslp->
+						      flags & 1) == 0))
+							inode->i_size +=
+							    1;
+						break;
+					}
+
+					/*
+					 * If this component record isn't
+					 * continued, then append a '/'.
+					 */
+					if (!rootflag
+					    && (oldslp->flags & 1) == 0)
+						inode->i_size += 1;
+				}
+			}
+			symlink_len = inode->i_size;
+			break;
+		case SIG('R', 'E'):
+			printk(KERN_WARNING "Attempt to read inode for "
+					"relocated directory\n");
+			goto out;
+		case SIG('C', 'L'):
+			if (flags & RR_RELOC_DE) {
+				printk(KERN_ERR
+				       "ISOFS: Recursive directory relocation "
+				       "is not supported\n");
+				goto eio;
+			}
+			reloc_block = isonum_733(rr->u.CL.location);
+			if (reloc_block == ISOFS_I(inode)->i_iget5_block &&
+			    ISOFS_I(inode)->i_iget5_offset == 0) {
+				printk(KERN_ERR
+				       "ISOFS: Directory relocation points to "
+				       "itself\n");
+				goto eio;
+			}
+			ISOFS_I(inode)->i_first_extent = reloc_block;
+			reloc = isofs_iget_reloc(inode->i_sb, reloc_block, 0);
+			if (IS_ERR(reloc)) {
+				ret = PTR_ERR(reloc);
+				goto out;
+			}
+			inode->i_mode = reloc->i_mode;
+			set_nlink(inode, reloc->i_nlink);
+			inode->i_uid = reloc->i_uid;
+			inode->i_gid = reloc->i_gid;
+			inode->i_rdev = reloc->i_rdev;
+			inode->i_size = reloc->i_size;
+			inode->i_blocks = reloc->i_blocks;
+			inode_set_atime_to_ts(inode, inode_get_atime(reloc));
+			inode_set_ctime_to_ts(inode, inode_get_ctime(reloc));
+			inode_set_mtime_to_ts(inode, inode_get_mtime(reloc));
+			iput(reloc);
+			break;
+#ifdef CONFIG_ZISOFS
+		case SIG('Z', 'F'): {
+			int algo;
+
+			if (ISOFS_SB(inode->i_sb)->s_nocompress)
+				break;
+			algo = isonum_721(rr->u.ZF.algorithm);
+			if (algo == SIG('p', 'z')) {
+				int block_shift =
+					isonum_711(&rr->u.ZF.parms[1]);
+				if (block_shift > 17) {
+					printk(KERN_WARNING "isofs: "
+						"Can't handle ZF block "
+						"size of 2^%d\n",
+						block_shift);
+				} else {
+					/*
+					 * Note: we don't change
+					 * i_blocks here
+					 */
+					ISOFS_I(inode)->i_file_format =
+						isofs_file_compressed;
+					/*
+					 * Parameters to compression
+					 * algorithm (header size,
+					 * block size)
+					 */
+					ISOFS_I(inode)->i_format_parm[0] =
+						isonum_711(&rr->u.ZF.parms[0]);
+					ISOFS_I(inode)->i_format_parm[1] =
+						isonum_711(&rr->u.ZF.parms[1]);
+					inode->i_size =
+					    isonum_733(rr->u.ZF.
+						       real_size);
+				}
+			} else {
+				printk(KERN_WARNING
+				       "isofs: Unknown ZF compression "
+						"algorithm: %c%c\n",
+				       rr->u.ZF.algorithm[0],
+				       rr->u.ZF.algorithm[1]);
+			}
+			break;
+		}
+#endif
+		default:
+			break;
+		}
+	}
+	ret = rock_continue(&rs);
+	if (ret == 0)
+		goto repeat;
+	if (ret == 1)
+		ret = 0;
+out:
+	kfree(rs.buffer);
+	return ret;
+eio:
+	ret = -EIO;
+	goto out;
+}
+
+static char *get_symlink_chunk(char *rpnt, struct rock_ridge *rr, char *plimit)
+{
+	int slen;
+	int rootflag;
+	struct SL_component *oldslp;
+	struct SL_component *slp;
+	slen = rr->len - 5;
+	slp = &rr->u.SL.link;
+	while (slen > 1) {
+		rootflag = 0;
+		/*
+		 * A component is slp->len + 2 bytes (a two-byte header plus
+		 * len bytes of text).  If it does not fit in the bytes left in
+		 * the SL record the record is malformed: fail like the plimit
+		 * checks below so readlink() returns -EIO, not a truncated path.
+		 */
+		if (slp->len + 2 > slen)
+			return NULL;
+		switch (slp->flags & ~1) {
+		case 0:
+			if (slp->len > plimit - rpnt)
+				return NULL;
+			memcpy(rpnt, slp->text, slp->len);
+			rpnt += slp->len;
+			break;
+		case 2:
+			if (rpnt >= plimit)
+				return NULL;
+			*rpnt++ = '.';
+			break;
+		case 4:
+			if (2 > plimit - rpnt)
+				return NULL;
+			*rpnt++ = '.';
+			*rpnt++ = '.';
+			break;
+		case 8:
+			if (rpnt >= plimit)
+				return NULL;
+			rootflag = 1;
+			*rpnt++ = '/';
+			break;
+		default:
+			printk("Symlink component flag not implemented (%d)\n",
+			       slp->flags);
+		}
+		slen -= slp->len + 2;
+		oldslp = slp;
+		slp = (struct SL_component *)((char *)slp + slp->len + 2);
+
+		if (slen < 2) {
+			/*
+			 * If there is another SL record, and this component
+			 * record isn't continued, then add a slash.
+			 */
+			if ((!rootflag) && (rr->u.SL.flags & 1) &&
+			    !(oldslp->flags & 1)) {
+				if (rpnt >= plimit)
+					return NULL;
+				*rpnt++ = '/';
+			}
+			break;
+		}
+
+		/*
+		 * If this component record isn't continued, then append a '/'.
+		 */
+		if (!rootflag && !(oldslp->flags & 1)) {
+			if (rpnt >= plimit)
+				return NULL;
+			*rpnt++ = '/';
+		}
+	}
+	return rpnt;
+}
+
+int parse_rock_ridge_inode(struct iso_directory_record *de, struct inode *inode,
+			   int relocated)
+{
+	int flags = relocated ? RR_RELOC_DE : 0;
+	int result = parse_rock_ridge_inode_internal(de, inode, flags);
+
+	/*
+	 * if rockridge flag was reset and we didn't look for attributes
+	 * behind eventual XA attributes, have a look there
+	 */
+	if ((ISOFS_SB(inode->i_sb)->s_rock_offset == -1)
+	    && (ISOFS_SB(inode->i_sb)->s_rock == 2)) {
+		result = parse_rock_ridge_inode_internal(de, inode,
+							 flags | RR_REGARD_XA);
+	}
+	return result;
+}
+
+/*
+ * read_folio() for symlinks: reads symlink contents into the folio and either
+ * makes it uptodate and returns 0 or returns error (-EIO)
+ */
+static int rock_ridge_symlink_read_folio(struct file *file, struct folio *folio)
+{
+	struct inode *inode = folio->mapping->host;
+	struct iso_inode_info *ei = ISOFS_I(inode);
+	struct isofs_sb_info *sbi = ISOFS_SB(inode->i_sb);
+	char *link = folio_address(folio);
+	unsigned long bufsize = ISOFS_BUFFER_SIZE(inode);
+	struct buffer_head *bh;
+	char *rpnt = link;
+	unsigned char *pnt;
+	struct iso_directory_record *raw_de;
+	unsigned long block, offset;
+	int sig;
+	struct rock_ridge *rr;
+	struct rock_state rs;
+	int ret;
+
+	if (!sbi->s_rock)
+		goto error;
+
+	init_rock_state(&rs, inode);
+	block = ei->i_iget5_block;
+	bh = sb_bread(inode->i_sb, block);
+	if (!bh)
+		goto out_noread;
+
+	offset = ei->i_iget5_offset;
+	pnt = (unsigned char *)bh->b_data + offset;
+
+	raw_de = (struct iso_directory_record *)pnt;
+
+	/*
+	 * If we go past the end of the buffer, there is some sort of error.
+	 */
+	if (offset + *pnt > bufsize)
+		goto out_bad_span;
+
+	/*
+	 * Now test for possible Rock Ridge extensions which will override
+	 * some of these numbers in the inode structure.
+	 */
+
+	setup_rock_ridge(raw_de, inode, &rs);
+
+repeat:
+	while (rs.len > 2) { /* There may be one byte for padding somewhere */
+		rr = (struct rock_ridge *)rs.chr;
+		if (rr->len < 3)
+			goto out;	/* Something got screwed up here */
+		sig = isonum_721(rs.chr);
+		if (rock_check_overflow(&rs, sig))
+			goto out;
+		rs.chr += rr->len;
+		rs.len -= rr->len;
+		if (rs.len < 0)
+			goto out;	/* corrupted isofs */
+
+		switch (sig) {
+		case SIG('R', 'R'):
+			if ((rr->u.RR.flags[0] & RR_SL) == 0)
+				goto out;
+			break;
+		case SIG('S', 'P'):
+			if (check_sp(rr, inode))
+				goto out;
+			break;
+		case SIG('S', 'L'):
+			rpnt = get_symlink_chunk(rpnt, rr,
+						 link + (PAGE_SIZE - 1));
+			if (rpnt == NULL)
+				goto out;
+			break;
+		case SIG('C', 'E'):
+			/* This tells is if there is a continuation record */
+			rs.cont_extent = isonum_733(rr->u.CE.extent);
+			rs.cont_offset = isonum_733(rr->u.CE.offset);
+			rs.cont_size = isonum_733(rr->u.CE.size);
+			break;
+		default:
+			break;
+		}
+	}
+	ret = rock_continue(&rs);
+	if (ret == 0)
+		goto repeat;
+	if (ret < 0)
+		goto fail;
+
+	if (rpnt == link)
+		goto fail;
+	brelse(bh);
+	*rpnt = '\0';
+	ret = 0;
+end:
+	folio_end_read(folio, ret == 0);
+	return ret;
+
+	/* error exit from macro */
+out:
+	kfree(rs.buffer);
+	goto fail;
+out_noread:
+	printk("unable to read i-node block");
+	goto fail;
+out_bad_span:
+	printk("symlink spans iso9660 blocks\n");
+fail:
+	brelse(bh);
+error:
+	ret = -EIO;
+	goto end;
+}
+
+const struct address_space_operations isofs_symlink_aops = {
+	.read_folio = rock_ridge_symlink_read_folio
+};

linux-7.2.3/fs/isofs/rock.h

@@ -0,0 +1,119 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * These structs are used by the system-use-sharing protocol, in which the
+ * Rock Ridge extensions are embedded.  It is quite possible that other
+ * extensions are present on the disk, and this is fine as long as they
+ * all use SUSP
+ */
+
+struct SU_SP_s {
+	__u8 magic[2];
+	__u8 skip;
+} __attribute__ ((packed));
+
+struct SU_CE_s {
+	__u8 extent[8];
+	__u8 offset[8];
+	__u8 size[8];
+};
+
+struct SU_ER_s {
+	__u8 len_id;
+	__u8 len_des;
+	__u8 len_src;
+	__u8 ext_ver;
+	__u8 data[];
+} __attribute__ ((packed));
+
+struct RR_RR_s {
+	__u8 flags[1];
+} __attribute__ ((packed));
+
+struct RR_PX_s {
+	__u8 mode[8];
+	__u8 n_links[8];
+	__u8 uid[8];
+	__u8 gid[8];
+};
+
+struct RR_PN_s {
+	__u8 dev_high[8];
+	__u8 dev_low[8];
+};
+
+struct SL_component {
+	__u8 flags;
+	__u8 len;
+	__u8 text[] __counted_by(len);
+} __attribute__ ((packed));
+
+struct RR_SL_s {
+	__u8 flags;
+	struct SL_component link;
+} __attribute__ ((packed));
+
+struct RR_NM_s {
+	__u8 flags;
+	char name[];
+} __attribute__ ((packed));
+
+struct RR_CL_s {
+	__u8 location[8];
+};
+
+struct RR_PL_s {
+	__u8 location[8];
+};
+
+struct RR_TF_s {
+	__u8 flags;
+	__u8 data[];
+} __attribute__ ((packed));
+
+/* Linux-specific extension for transparent decompression */
+struct RR_ZF_s {
+	__u8 algorithm[2];
+	__u8 parms[2];
+	__u8 real_size[8];
+};
+
+/*
+ * These are the bits and their meanings for flags in the TF structure.
+ */
+#define TF_CREATE 1
+#define TF_MODIFY 2
+#define TF_ACCESS 4
+#define TF_ATTRIBUTES 8
+#define TF_BACKUP 16
+#define TF_EXPIRATION 32
+#define TF_EFFECTIVE 64
+#define TF_LONG_FORM 128
+
+struct rock_ridge {
+	__u8 signature[2];
+	__u8 len;
+	__u8 version;
+	union {
+		struct SU_SP_s SP;
+		struct SU_CE_s CE;
+		struct SU_ER_s ER;
+		struct RR_RR_s RR;
+		struct RR_PX_s PX;
+		struct RR_PN_s PN;
+		struct RR_SL_s SL;
+		struct RR_NM_s NM;
+		struct RR_CL_s CL;
+		struct RR_PL_s PL;
+		struct RR_TF_s TF;
+		struct RR_ZF_s ZF;
+	} u;
+};
+
+#define RR_PX 1			/* POSIX attributes */
+#define RR_PN 2			/* POSIX devices */
+#define RR_SL 4			/* Symbolic link */
+#define RR_NM 8			/* Alternate Name */
+#define RR_CL 16		/* Child link */
+#define RR_PL 32		/* Parent link */
+#define RR_RE 64		/* Relocation directory */
+#define RR_TF 128		/* Timestamps */

linux-7.2.3/fs/isofs/util.c

@@ -0,0 +1,86 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  linux/fs/isofs/util.c
+ */
+
+#include <linux/time.h>
+#include "isofs.h"
+
+/* 
+ * We have to convert from a MM/DD/YY format to the Unix ctime format.
+ * We have to take into account leap years and all of that good stuff.
+ * Unfortunately, the kernel does not have the information on hand to
+ * take into account daylight savings time, but it shouldn't matter.
+ * The time stored should be localtime (with or without DST in effect),
+ * and the timezone offset should hold the offset required to get back
+ * to GMT.  Thus  we should always be correct.
+ */
+
+struct timespec64 iso_date(u8 *p, int flags)
+{
+	int year, month, day, hour, minute, second, tz;
+	struct timespec64 ts;
+
+	if (flags & ISO_DATE_LONG_FORM) {
+		year = (p[0] - '0') * 1000 +
+		       (p[1] - '0') * 100 +
+		       (p[2] - '0') * 10 +
+		       (p[3] - '0') - 1900;
+		month = ((p[4] - '0') * 10 + (p[5] - '0'));
+		day = ((p[6] - '0') * 10 + (p[7] - '0'));
+		hour = ((p[8] - '0') * 10 + (p[9] - '0'));
+		minute = ((p[10] - '0') * 10 + (p[11] - '0'));
+		second = ((p[12] - '0') * 10 + (p[13] - '0'));
+		ts.tv_nsec = ((p[14] - '0') * 10 + (p[15] - '0')) * 10000000;
+		tz = p[16];
+	} else {
+		year = p[0];
+		month = p[1];
+		day = p[2];
+		hour = p[3];
+		minute = p[4];
+		second = p[5];
+		ts.tv_nsec = 0;
+		/* High sierra has no time zone */
+		tz = flags & ISO_DATE_HIGH_SIERRA ? 0 : p[6];
+	}
+
+	if (year < 0) {
+		ts.tv_sec = 0;
+	} else {
+		ts.tv_sec = mktime64(year+1900, month, day, hour, minute, second);
+
+		/* sign extend */
+		if (tz & 0x80)
+			tz |= (-1 << 8);
+
+		/* 
+		 * The timezone offset is unreliable on some disks,
+		 * so we make a sanity check.  In no case is it ever
+		 * more than 13 hours from GMT, which is 52*15min.
+		 * The time is always stored in localtime with the
+		 * timezone offset being what get added to GMT to
+		 * get to localtime.  Thus we need to subtract the offset
+		 * to get to true GMT, which is what we store the time
+		 * as internally.  On the local system, the user may set
+		 * their timezone any way they wish, of course, so GMT
+		 * gets converted back to localtime on the receiving
+		 * system.
+		 *
+		 * NOTE: mkisofs in versions prior to mkisofs-1.10 had
+		 * the sign wrong on the timezone offset.  This has now
+		 * been corrected there too, but if you are getting screwy
+		 * results this may be the explanation.  If enough people
+		 * complain, a user configuration option could be added
+		 * to add the timezone offset in with the wrong sign
+		 * for 'compatibility' with older discs, but I cannot see how
+		 * it will matter that much.
+		 *
+		 * Thanks to kuhlmav@elec.canterbury.ac.nz (Volker Kuhlmann)
+		 * for pointing out the sign error.
+		 */
+		if (-52 <= tz && tz <= 52)
+			ts.tv_sec -= tz * 15 * 60;
+	}
+	return ts;
+}

linux-7.2.3/fs/isofs/zisofs.h

@@ -0,0 +1,16 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/* ----------------------------------------------------------------------- *
+ *   
+ *   Copyright 2001 H. Peter Anvin - All Rights Reserved
+ *
+ * ----------------------------------------------------------------------- */
+
+/*
+ * Prototypes for functions exported from the compressed isofs subsystem
+ */
+
+#ifdef CONFIG_ZISOFS
+extern const struct address_space_operations zisofs_aops;
+extern int __init zisofs_init(void);
+extern void zisofs_cleanup(void);
+#endif