1 files changed, 17 insertions, 11 deletions

diff --git a/fs/libfs.c b/fs/libfs.c
index 279442b1fe96..14e0e9b18c8e 100644
--- a/fs/libfs.c
+++ b/fs/libfs.c
@@ -496,7 +496,7 @@ offset_dir_lookup(struct dentry *parent, loff_t offset)
 		found = find_positive_dentry(parent, NULL, false);
 	else {
 		rcu_read_lock();
-		child = mas_find(&mas, DIR_OFFSET_MAX);
+		child = mas_find_rev(&mas, DIR_OFFSET_MIN);
 		found = find_positive_dentry(parent, child, false);
 		rcu_read_unlock();
 	}
@@ -665,6 +665,7 @@ static int pseudo_fs_fill_super(struct super_block *s, struct fs_context *fc)
 	s->s_blocksize_bits = PAGE_SHIFT;
 	s->s_magic = ctx->magic;
 	s->s_op = ctx->ops ?: &simple_super_operations;
+	s->s_export_op = ctx->eops;
 	s->s_xattr = ctx->xattr;
 	s->s_time_gran = 1;
 	root = new_inode(s);
@@ -1646,10 +1647,14 @@ struct inode *alloc_anon_inode(struct super_block *s)
 	 * that it already _is_ on the dirty list.
 	 */
 	inode->i_state = I_DIRTY;
+	/*
+	 * Historically anonymous inodes don't have a type at all and
+	 * userspace has come to rely on this.
+	 */
 	inode->i_mode = S_IRUSR | S_IWUSR;
 	inode->i_uid = current_fsuid();
 	inode->i_gid = current_fsgid();
-	inode->i_flags |= S_PRIVATE;
+	inode->i_flags |= S_PRIVATE | S_ANON_INODE;
 	simple_inode_init_ts(inode);
 	return inode;
 }
@@ -1781,7 +1786,7 @@ int generic_ci_d_compare(const struct dentry *dentry, unsigned int len,
 {
 	const struct dentry *parent;
 	const struct inode *dir;
-	char strbuf[DNAME_INLINE_LEN];
+	union shortname_store strbuf;
 	struct qstr qstr;
 
 	/*
@@ -1801,22 +1806,23 @@ int generic_ci_d_compare(const struct dentry *dentry, unsigned int len,
 	if (!dir || !IS_CASEFOLDED(dir))
 		return 1;
 
+	qstr.len = len;
+	qstr.name = str;
 	/*
 	 * If the dentry name is stored in-line, then it may be concurrently
 	 * modified by a rename.  If this happens, the VFS will eventually retry
 	 * the lookup, so it doesn't matter what ->d_compare() returns.
 	 * However, it's unsafe to call utf8_strncasecmp() with an unstable
 	 * string.  Therefore, we have to copy the name into a temporary buffer.
+	 * As above, len is guaranteed to match str, so the shortname case
+	 * is exactly when str points to ->d_shortname.
 	 */
-	if (len <= DNAME_INLINE_LEN - 1) {
-		memcpy(strbuf, str, len);
-		strbuf[len] = 0;
-		str = strbuf;
+	if (qstr.name == dentry->d_shortname.string) {
+		strbuf = dentry->d_shortname; // NUL is guaranteed to be in there
+		qstr.name = strbuf.string;
 		/* prevent compiler from optimizing out the temporary buffer */
 		barrier();
 	}
-	qstr.len = len;
-	qstr.name = str;
 
 	return utf8_strncasecmp(dentry->d_sb->s_encoding, name, &qstr);
 }
@@ -2111,7 +2117,7 @@ struct timespec64 simple_inode_init_ts(struct inode *inode)
 }
 EXPORT_SYMBOL(simple_inode_init_ts);
 
-static inline struct dentry *get_stashed_dentry(struct dentry **stashed)
+struct dentry *stashed_dentry_get(struct dentry **stashed)
 {
 	struct dentry *dentry;
 
@@ -2213,7 +2219,7 @@ int path_from_stashed(struct dentry **stashed, struct vfsmount *mnt, void *data,
 	const struct stashed_operations *sops = mnt->mnt_sb->s_fs_info;
 
 	/* See if dentry can be reused. */
-	path->dentry = get_stashed_dentry(stashed);
+	path->dentry = stashed_dentry_get(stashed);
 	if (path->dentry) {
 		sops->put_data(data);
 		goto out_path;