+ fat-roll-back-the-new-entry-when-create-mkdir-fails-to-build-the-inode.patch added to mm-nonmm-unstable branch

[Andrew Morton <akpm@linux-foundation.org>]

The patch titled
     Subject: fat: roll back the new entry when create/mkdir fails to build the inode
has been added to the -mm mm-nonmm-unstable branch.  Its filename is
     fat-roll-back-the-new-entry-when-create-mkdir-fails-to-build-the-inode.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/fat-roll-back-the-new-entry-when-create-mkdir-fails-to-build-the-inode.patch

This patch will later appear in the mm-nonmm-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------
From: zhoumin <teczm@foxmail.com>
Subject: fat: roll back the new entry when create/mkdir fails to build the inode
Date: Mon, 12 Oct 2026 21:20:06 +0800

vfat_create(), vfat_mkdir(), msdos_create() and msdos_mkdir() add the
on-disk entry before calling fat_build_inode() to set up the VFS inode. 
If fat_build_inode() fails, the error is returned but the entry stays on
disk and the file or directory shows up after remount.

Remove the entry in that case.  For mkdir, also free the directory cluster
and decrement the parent's link count.

Link: https://lore.kernel.org/tencent_4EDD66523CED299DB0C99498B4D8C939A009@qq.com
Signed-off-by: zhoumin <teczm@foxmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
---

 fs/fat/namei_msdos.c |   22 ++++++++++++++++++----
 fs/fat/namei_vfat.c  |   22 ++++++++++++++++++----
 2 files changed, 36 insertions(+), 8 deletions(-)

--- a/fs/fat/namei_msdos.c~fat-roll-back-the-new-entry-when-create-mkdir-fails-to-build-the-inode
+++ a/fs/fat/namei_msdos.c
@@ -292,11 +292,17 @@ static int msdos_create(struct mnt_idmap
 	if (err)
 		goto out;
 	inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
-	brelse(sinfo.bh);
 	if (IS_ERR(inode)) {
+		int err2;
+
 		err = PTR_ERR(inode);
+		err2 = fat_remove_entries(dir, &sinfo);
+		if (err2)
+			fat_msg(sb, KERN_WARNING,
+				"failed to roll back new entry (%d)", err2);
 		goto out;
 	}
+	brelse(sinfo.bh);
 	fat_truncate_time(inode, &ts, FAT_UPDATE_ATIME | FAT_UPDATE_CMTIME);
 	/* timestamp is already written, so mark_inode_dirty() is unneeded. */
 
@@ -381,12 +387,20 @@ static struct dentry *msdos_mkdir(struct
 	inc_nlink(dir);
 
 	inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
-	brelse(sinfo.bh);
 	if (IS_ERR(inode)) {
+		int err2;
+
 		err = PTR_ERR(inode);
-		/* the directory was completed, just return a error */
-		goto out;
+		err2 = fat_remove_entries(dir, &sinfo);
+		if (err2) {
+			fat_msg(sb, KERN_WARNING,
+				"failed to roll back new entry (%d)", err2);
+			goto out;
+		}
+		drop_nlink(dir);
+		goto out_free;
 	}
+	brelse(sinfo.bh);
 	set_nlink(inode, 2);
 	fat_truncate_time(inode, &ts, FAT_UPDATE_ATIME | FAT_UPDATE_CMTIME);
 	/* timestamp is already written, so mark_inode_dirty() is unneeded. */
--- a/fs/fat/namei_vfat.c~fat-roll-back-the-new-entry-when-create-mkdir-fails-to-build-the-inode
+++ a/fs/fat/namei_vfat.c
@@ -771,11 +771,17 @@ static int vfat_create(struct mnt_idmap
 	inode_inc_iversion(dir);
 
 	inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
-	brelse(sinfo.bh);
 	if (IS_ERR(inode)) {
+		int err2;
+
 		err = PTR_ERR(inode);
+		err2 = fat_remove_entries(dir, &sinfo);
+		if (err2)
+			fat_msg(sb, KERN_WARNING,
+				"failed to roll back new entry (%d)", err2);
 		goto out;
 	}
+	brelse(sinfo.bh);
 	inode_inc_iversion(inode);
 
 	d_instantiate(dentry, inode);
@@ -870,12 +876,20 @@ static struct dentry *vfat_mkdir(struct
 	inc_nlink(dir);
 
 	inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
-	brelse(sinfo.bh);
 	if (IS_ERR(inode)) {
+		int err2;
+
 		err = PTR_ERR(inode);
-		/* the directory was completed, just return a error */
-		goto out;
+		err2 = fat_remove_entries(dir, &sinfo);
+		if (err2) {
+			fat_msg(sb, KERN_WARNING,
+				"failed to roll back new entry (%d)", err2);
+			goto out;
+		}
+		drop_nlink(dir);
+		goto out_free;
 	}
+	brelse(sinfo.bh);
 	inode_inc_iversion(inode);
 	set_nlink(inode, 2);
 
_

Patches currently in -mm which might be from teczm@foxmail.com are

fat-roll-back-the-new-entry-when-create-mkdir-fails-to-build-the-inode.patch