v4.19.13 snapshot.
diff --git a/fs/udf/symlink.c b/fs/udf/symlink.c
new file mode 100644
index 0000000..6023c97
--- /dev/null
+++ b/fs/udf/symlink.c
@@ -0,0 +1,191 @@
+/*
+ * symlink.c
+ *
+ * PURPOSE
+ * Symlink handling routines for the OSTA-UDF(tm) filesystem.
+ *
+ * COPYRIGHT
+ * This file is distributed under the terms of the GNU General Public
+ * License (GPL). Copies of the GPL can be obtained from:
+ * ftp://prep.ai.mit.edu/pub/gnu/GPL
+ * Each contributing author retains all rights to their own work.
+ *
+ * (C) 1998-2001 Ben Fennema
+ * (C) 1999 Stelias Computing Inc
+ *
+ * HISTORY
+ *
+ * 04/16/99 blf Created.
+ *
+ */
+
+#include "udfdecl.h"
+#include <linux/uaccess.h>
+#include <linux/errno.h>
+#include <linux/fs.h>
+#include <linux/time.h>
+#include <linux/mm.h>
+#include <linux/stat.h>
+#include <linux/pagemap.h>
+#include "udf_i.h"
+
+static int udf_pc_to_char(struct super_block *sb, unsigned char *from,
+ int fromlen, unsigned char *to, int tolen)
+{
+ struct pathComponent *pc;
+ int elen = 0;
+ int comp_len;
+ unsigned char *p = to;
+
+ /* Reserve one byte for terminating \0 */
+ tolen--;
+ while (elen < fromlen) {
+ pc = (struct pathComponent *)(from + elen);
+ elen += sizeof(struct pathComponent);
+ switch (pc->componentType) {
+ case 1:
+ /*
+ * Symlink points to some place which should be agreed
+ * upon between originator and receiver of the media. Ignore.
+ */
+ if (pc->lengthComponentIdent > 0) {
+ elen += pc->lengthComponentIdent;
+ break;
+ }
+ /* Fall through */
+ case 2:
+ if (tolen == 0)
+ return -ENAMETOOLONG;
+ p = to;
+ *p++ = '/';
+ tolen--;
+ break;
+ case 3:
+ if (tolen < 3)
+ return -ENAMETOOLONG;
+ memcpy(p, "../", 3);
+ p += 3;
+ tolen -= 3;
+ break;
+ case 4:
+ if (tolen < 2)
+ return -ENAMETOOLONG;
+ memcpy(p, "./", 2);
+ p += 2;
+ tolen -= 2;
+ /* that would be . - just ignore */
+ break;
+ case 5:
+ elen += pc->lengthComponentIdent;
+ if (elen > fromlen)
+ return -EIO;
+ comp_len = udf_get_filename(sb, pc->componentIdent,
+ pc->lengthComponentIdent,
+ p, tolen);
+ if (comp_len < 0)
+ return comp_len;
+
+ p += comp_len;
+ tolen -= comp_len;
+ if (tolen == 0)
+ return -ENAMETOOLONG;
+ *p++ = '/';
+ tolen--;
+ break;
+ }
+ }
+ if (p > to + 1)
+ p[-1] = '\0';
+ else
+ p[0] = '\0';
+ return 0;
+}
+
+static int udf_symlink_filler(struct file *file, struct page *page)
+{
+ struct inode *inode = page->mapping->host;
+ struct buffer_head *bh = NULL;
+ unsigned char *symlink;
+ int err;
+ unsigned char *p = page_address(page);
+ struct udf_inode_info *iinfo;
+ uint32_t pos;
+
+ /* We don't support symlinks longer than one block */
+ if (inode->i_size > inode->i_sb->s_blocksize) {
+ err = -ENAMETOOLONG;
+ goto out_unmap;
+ }
+
+ iinfo = UDF_I(inode);
+ pos = udf_block_map(inode, 0);
+
+ down_read(&iinfo->i_data_sem);
+ if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB) {
+ symlink = iinfo->i_ext.i_data + iinfo->i_lenEAttr;
+ } else {
+ bh = sb_bread(inode->i_sb, pos);
+
+ if (!bh) {
+ err = -EIO;
+ goto out_unlock_inode;
+ }
+
+ symlink = bh->b_data;
+ }
+
+ err = udf_pc_to_char(inode->i_sb, symlink, inode->i_size, p, PAGE_SIZE);
+ brelse(bh);
+ if (err)
+ goto out_unlock_inode;
+
+ up_read(&iinfo->i_data_sem);
+ SetPageUptodate(page);
+ unlock_page(page);
+ return 0;
+
+out_unlock_inode:
+ up_read(&iinfo->i_data_sem);
+ SetPageError(page);
+out_unmap:
+ unlock_page(page);
+ return err;
+}
+
+static int udf_symlink_getattr(const struct path *path, struct kstat *stat,
+ u32 request_mask, unsigned int flags)
+{
+ struct dentry *dentry = path->dentry;
+ struct inode *inode = d_backing_inode(dentry);
+ struct page *page;
+
+ generic_fillattr(inode, stat);
+ page = read_mapping_page(inode->i_mapping, 0, NULL);
+ if (IS_ERR(page))
+ return PTR_ERR(page);
+ /*
+ * UDF uses non-trivial encoding of symlinks so i_size does not match
+ * number of characters reported by readlink(2) which apparently some
+ * applications expect. Also POSIX says that "The value returned in the
+ * st_size field shall be the length of the contents of the symbolic
+ * link, and shall not count a trailing null if one is present." So
+ * let's report the length of string returned by readlink(2) for
+ * st_size.
+ */
+ stat->size = strlen(page_address(page));
+ put_page(page);
+
+ return 0;
+}
+
+/*
+ * symlinks can't do much...
+ */
+const struct address_space_operations udf_symlink_aops = {
+ .readpage = udf_symlink_filler,
+};
+
+const struct inode_operations udf_symlink_inode_operations = {
+ .get_link = page_get_link,
+ .getattr = udf_symlink_getattr,
+};