From abb7c742397324f8676c5b622effdce911cd52e3 Mon Sep 17 00:00:00 2001
From: Al Viro <viro@zeniv.linux.org.uk>
Date: Thu, 19 Jan 2023 20:05:43 -0500
Subject: sysv: fix handling of delete_entry and set_link failures

similar to minixfs series - make sysv_set_link() report failures,
lift dir_put_page() into the callers of sysv_set_link() and
sysv_delete_entry(), make sysv_rename() handle failures in both.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 fs/sysv/dir.c   | 16 ++++++++++------
 fs/sysv/namei.c | 33 +++++++++++++++++++--------------
 fs/sysv/sysv.h  |  2 +-
 3 files changed, 30 insertions(+), 21 deletions(-)

(limited to 'fs/sysv')

diff --git a/fs/sysv/dir.c b/fs/sysv/dir.c
index 3ed98d66b152..999bceb99974 100644
--- a/fs/sysv/dir.c
+++ b/fs/sysv/dir.c
@@ -249,10 +249,12 @@ int sysv_delete_entry(struct sysv_dir_entry *de, struct page *page)
 
 	lock_page(page);
 	err = sysv_prepare_chunk(page, pos, SYSV_DIRSIZE);
-	BUG_ON(err);
+	if (err) {
+		unlock_page(page);
+		return err;
+	}
 	de->inode = 0;
 	dir_commit_chunk(page, pos, SYSV_DIRSIZE);
-	dir_put_page(page, de);
 	inode->i_ctime = inode->i_mtime = current_time(inode);
 	mark_inode_dirty(inode);
 	return sysv_handle_dirsync(inode);
@@ -335,7 +337,7 @@ not_empty:
 }
 
 /* Releases the page */
-void sysv_set_link(struct sysv_dir_entry *de, struct page *page,
+int sysv_set_link(struct sysv_dir_entry *de, struct page *page,
 	struct inode *inode)
 {
 	struct inode *dir = page->mapping->host;
@@ -344,13 +346,15 @@ void sysv_set_link(struct sysv_dir_entry *de, struct page *page,
 
 	lock_page(page);
 	err = sysv_prepare_chunk(page, pos, SYSV_DIRSIZE);
-	BUG_ON(err);
+	if (err) {
+		unlock_page(page);
+		return err;
+	}
 	de->inode = cpu_to_fs16(SYSV_SB(inode->i_sb), inode->i_ino);
 	dir_commit_chunk(page, pos, SYSV_DIRSIZE);
-	dir_put_page(page, de);
 	dir->i_mtime = dir->i_ctime = current_time(dir);
 	mark_inode_dirty(dir);
-	sysv_handle_dirsync(inode);
+	return sysv_handle_dirsync(inode);
 }
 
 /*
diff --git a/fs/sysv/namei.c b/fs/sysv/namei.c
index 371cf9012052..1bfe788851a9 100644
--- a/fs/sysv/namei.c
+++ b/fs/sysv/namei.c
@@ -153,19 +153,18 @@ static int sysv_unlink(struct inode * dir, struct dentry * dentry)
 	struct inode * inode = d_inode(dentry);
 	struct page * page;
 	struct sysv_dir_entry * de;
-	int err = -ENOENT;
+	int err;
 
 	de = sysv_find_entry(dentry, &page);
 	if (!de)
-		goto out;
-
-	err = sysv_delete_entry (de, page);
-	if (err)
-		goto out;
+		return -ENOENT;
 
-	inode->i_ctime = dir->i_ctime;
-	inode_dec_link_count(inode);
-out:
+	err = sysv_delete_entry(de, page);
+	if (!err) {
+		inode->i_ctime = dir->i_ctime;
+		inode_dec_link_count(inode);
+	}
+	dir_put_page(page, de);
 	return err;
 }
 
@@ -227,7 +226,10 @@ static int sysv_rename(struct user_namespace *mnt_userns, struct inode *old_dir,
 		new_de = sysv_find_entry(new_dentry, &new_page);
 		if (!new_de)
 			goto out_dir;
-		sysv_set_link(new_de, new_page, old_inode);
+		err = sysv_set_link(new_de, new_page, old_inode);
+		dir_put_page(new_page, new_de);
+		if (err)
+			goto out_dir;
 		new_inode->i_ctime = current_time(new_inode);
 		if (dir_de)
 			drop_nlink(new_inode);
@@ -240,14 +242,17 @@ static int sysv_rename(struct user_namespace *mnt_userns, struct inode *old_dir,
 			inode_inc_link_count(new_dir);
 	}
 
-	sysv_delete_entry(old_de, old_page);
+	err = sysv_delete_entry(old_de, old_page);
+	if (err)
+		goto out_dir;
+
 	mark_inode_dirty(old_inode);
 
 	if (dir_de) {
-		sysv_set_link(dir_de, dir_page, new_dir);
-		inode_dec_link_count(old_dir);
+		err = sysv_set_link(dir_de, dir_page, new_dir);
+		if (!err)
+			inode_dec_link_count(old_dir);
 	}
-	return 0;
 
 out_dir:
 	if (dir_de)
diff --git a/fs/sysv/sysv.h b/fs/sysv/sysv.h
index 50f19bfd8d10..7d900dce713d 100644
--- a/fs/sysv/sysv.h
+++ b/fs/sysv/sysv.h
@@ -154,7 +154,7 @@ extern int sysv_add_link(struct dentry *, struct inode *);
 extern int sysv_delete_entry(struct sysv_dir_entry *, struct page *);
 extern int sysv_make_empty(struct inode *, struct inode *);
 extern int sysv_empty_dir(struct inode *);
-extern void sysv_set_link(struct sysv_dir_entry *, struct page *,
+extern int sysv_set_link(struct sysv_dir_entry *, struct page *,
 			struct inode *);
 extern struct sysv_dir_entry *sysv_dotdot(struct inode *, struct page **);
 extern ino_t sysv_inode_by_name(struct dentry *);
-- 
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