+ fat-factor-out-reusable-code-in-vfat_rename-as-helper-functions.patch added to mm-nonmm-unstable branch

+ fat-factor-out-reusable-code-in-vfat_rename-as-helper-functions.patch added to mm-nonmm-unstable branch

[Andrew Morton]

The patch titled
     Subject: fat: factor out reusable code in vfat_rename() as helper functions
has been added to the -mm mm-nonmm-unstable branch.  Its filename is
     fat-factor-out-reusable-code-in-vfat_rename-as-helper-functions.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/fat-factor-out-reusable-code-in-vfat_rename-as-helper-functions.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: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Subject: fat: factor out reusable code in vfat_rename() as helper functions
Date: Fri, 10 Jun 2022 09:57:19 +0200

The vfat_rename() function is quite big and there are code blocks that can
be moved into helper functions.  This not only simplify the implementation
of that function but also allows these helpers to be reused.

For example, the helpers can be used by the handler of the RENAME_EXCHANGE
flag once this is implemented in a subsequent patch.

Link: https://lkml.kernel.org/r/20220610075721.1182745-3-javierm@redhat.com
Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Acked-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Cc: Alexander Larsson <alexl@redhat.com>
Cc: Christian Kellner <ckellner@redhat.com>
Cc: Chung-Chiang Cheng <cccheng@synology.com>
Cc: Colin Walters <walters@verbum.org>
Cc: Lennart Poettering <lennart@poettering.net>
Cc: Muhammad Usama Anjum <usama.anjum@collabora.com>
Cc: Peter Jones <pjones@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 fs/fat/namei_vfat.c |   89 ++++++++++++++++++++++++++----------------
 1 file changed, 57 insertions(+), 32 deletions(-)

--- a/fs/fat/namei_vfat.c~fat-factor-out-reusable-code-in-vfat_rename-as-helper-functions
+++ a/fs/fat/namei_vfat.c
@@ -889,16 +889,55 @@ out:
 	return err;
 }
 
+static int vfat_get_dotdot_de(struct inode *inode, struct buffer_head **bh,
+			      struct msdos_dir_entry **de)
+{
+	if (S_ISDIR(inode->i_mode)) {
+		if (fat_get_dotdot_entry(inode, bh, de))
+			return -EIO;
+	}
+	return 0;
+}
+
+static int vfat_sync_ipos(struct inode *dir, struct inode *inode)
+{
+	if (IS_DIRSYNC(dir))
+		return fat_sync_inode(inode);
+	mark_inode_dirty(inode);
+	return 0;
+}
+
+static int vfat_update_dotdot_de(struct inode *dir, struct inode *inode,
+				 struct buffer_head *dotdot_bh,
+				 struct msdos_dir_entry *dotdot_de)
+{
+	fat_set_start(dotdot_de, MSDOS_I(dir)->i_logstart);
+	mark_buffer_dirty_inode(dotdot_bh, inode);
+	if (IS_DIRSYNC(dir))
+		return sync_dirty_buffer(dotdot_bh);
+	return 0;
+}
+
+static void vfat_update_dir_metadata(struct inode *dir, struct timespec64 *ts)
+{
+	inode_inc_iversion(dir);
+	fat_truncate_time(dir, ts, S_CTIME | S_MTIME);
+	if (IS_DIRSYNC(dir))
+		(void)fat_sync_inode(dir);
+	else
+		mark_inode_dirty(dir);
+}
+
 static int vfat_rename(struct inode *old_dir, struct dentry *old_dentry,
 		       struct inode *new_dir, struct dentry *new_dentry)
 {
 	struct buffer_head *dotdot_bh;
-	struct msdos_dir_entry *dotdot_de;
+	struct msdos_dir_entry *dotdot_de = NULL;
 	struct inode *old_inode, *new_inode;
 	struct fat_slot_info old_sinfo, sinfo;
 	struct timespec64 ts;
 	loff_t new_i_pos;
-	int err, is_dir, update_dotdot, corrupt = 0;
+	int err, is_dir, corrupt = 0;
 	struct super_block *sb = old_dir->i_sb;
 
 	old_sinfo.bh = sinfo.bh = dotdot_bh = NULL;
@@ -909,15 +948,13 @@ static int vfat_rename(struct inode *old
 	if (err)
 		goto out;
 
-	is_dir = S_ISDIR(old_inode->i_mode);
-	update_dotdot = (is_dir && old_dir != new_dir);
-	if (update_dotdot) {
-		if (fat_get_dotdot_entry(old_inode, &dotdot_bh, &dotdot_de)) {
-			err = -EIO;
+	if (old_dir != new_dir) {
+		err = vfat_get_dotdot_de(old_inode, &dotdot_bh, &dotdot_de);
+		if (err)
 			goto out;
-		}
 	}
 
+	is_dir = S_ISDIR(old_inode->i_mode);
 	ts = current_time(old_dir);
 	if (new_inode) {
 		if (is_dir) {
@@ -938,21 +975,15 @@ static int vfat_rename(struct inode *old
 
 	fat_detach(old_inode);
 	fat_attach(old_inode, new_i_pos);
-	if (IS_DIRSYNC(new_dir)) {
-		err = fat_sync_inode(old_inode);
+	err = vfat_sync_ipos(new_dir, old_inode);
+	if (err)
+		goto error_inode;
+
+	if (dotdot_de) {
+		err = vfat_update_dotdot_de(new_dir, old_inode, dotdot_bh,
+					    dotdot_de);
 		if (err)
-			goto error_inode;
-	} else
-		mark_inode_dirty(old_inode);
-
-	if (update_dotdot) {
-		fat_set_start(dotdot_de, MSDOS_I(new_dir)->i_logstart);
-		mark_buffer_dirty_inode(dotdot_bh, old_inode);
-		if (IS_DIRSYNC(new_dir)) {
-			err = sync_dirty_buffer(dotdot_bh);
-			if (err)
-				goto error_dotdot;
-		}
+			goto error_dotdot;
 		drop_nlink(old_dir);
 		if (!new_inode)
  			inc_nlink(new_dir);
@@ -962,12 +993,7 @@ static int vfat_rename(struct inode *old
 	old_sinfo.bh = NULL;
 	if (err)
 		goto error_dotdot;
-	inode_inc_iversion(old_dir);
-	fat_truncate_time(old_dir, &ts, S_CTIME|S_MTIME);
-	if (IS_DIRSYNC(old_dir))
-		(void)fat_sync_inode(old_dir);
-	else
-		mark_inode_dirty(old_dir);
+	vfat_update_dir_metadata(old_dir, &ts);
 
 	if (new_inode) {
 		drop_nlink(new_inode);
@@ -987,10 +1013,9 @@ error_dotdot:
 	/* data cluster is shared, serious corruption */
 	corrupt = 1;
 
-	if (update_dotdot) {
-		fat_set_start(dotdot_de, MSDOS_I(old_dir)->i_logstart);
-		mark_buffer_dirty_inode(dotdot_bh, old_inode);
-		corrupt |= sync_dirty_buffer(dotdot_bh);
+	if (dotdot_de) {
+		corrupt |= vfat_update_dotdot_de(old_dir, old_inode, dotdot_bh,
+						 dotdot_de);
 	}
 error_inode:
 	fat_detach(old_inode);
_

Patches currently in -mm which might be from hirofumi@mail.parknet.co.jp are

fat-factor-out-reusable-code-in-vfat_rename-as-helper-functions.patch