udf: Fix data integrity writeout issues

UDF could fail to properly write out inode on fsync(2) due to races
with WB_SYNC_NONE writeback. Several racing fsyncs could also result in
some fsync returning earlier than all metadata buffers were properly
persisted.

Fix all these issues by using new .sync_inode_metadata method which
makes sure all inode related metadata is written to disk during any
WB_SYNC_ALL writeback.

Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://patch.msgid.link/20260727104923.3828017-30-jack@suse.cz
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>

fs/udf/dir.c

@@ -157,6 +157,6 @@ const struct file_operations udf_dir_operations = {
 	.read			= generic_read_dir,
 	.iterate_shared		= udf_readdir,
 	.unlocked_ioctl		= udf_ioctl,
-	.fsync			= udf_fsync,
+	.fsync			= simple_fsync,
 	.setlease		= generic_setlease,
 };

fs/udf/file.c

@@ -198,13 +198,6 @@ static int udf_file_mmap(struct file *file, struct vm_area_struct *vma)
 	return 0;
 }
 
-int udf_fsync(struct file *file, loff_t start, loff_t end, int datasync)
-{
-	return mmb_fsync(file,
-			&UDF_I(file->f_mapping->host)->i_metadata_bhs,
-			start, end, datasync);
-}
-
 const struct file_operations udf_file_operations = {
 	.read_iter		= generic_file_read_iter,
 	.unlocked_ioctl		= udf_ioctl,
@@ -212,7 +205,7 @@ const struct file_operations udf_file_operations = {
 	.mmap			= udf_file_mmap,
 	.write_iter		= udf_file_write_iter,
 	.release		= udf_release_file,
-	.fsync			= udf_fsync,
+	.fsync			= simple_fsync,
 	.splice_read		= filemap_splice_read,
 	.splice_write		= iter_file_splice_write,
 	.llseek			= generic_file_llseek,

fs/udf/inode.c

@@ -142,7 +142,9 @@ void udf_evict_inode(struct inode *inode)
 		if (!inode->i_nlink) {
 			want_delete = 1;
 			udf_setsize(inode, 0);
-			udf_update_inode(inode, IS_SYNC(inode));
+			udf_update_inode(inode, 0);
+			if (IS_SYNC(inode))
+				udf_sync_inode_metadata(inode, NULL);
 		}
 		if (iinfo->i_alloc_type != ICBTAG_FLAG_AD_IN_ICB &&
 		    inode->i_size != iinfo->i_lenExtents) {
@@ -1710,6 +1712,30 @@ int udf_write_inode(struct inode *inode, struct writeback_control *wbc)
 	return udf_update_inode(inode, wbc->sync_mode == WB_SYNC_ALL);
 }
 
+int udf_sync_inode_metadata(struct inode *inode, struct writeback_control *wbc)
+{
+	struct buffer_head *bh;
+	int err = 0;
+
+	bh = sb_getblk(inode->i_sb,
+			udf_get_lb_pblock(inode->i_sb,
+					  &UDF_I(inode)->i_location, 0));
+	if (!bh)
+		return -EIO;
+
+	sync_dirty_buffer(bh);
+	if (buffer_write_io_error(bh)) {
+		udf_warn(inode->i_sb, "IO error syncing udf inode [%08llx]\n",
+			 inode->i_ino);
+		err = -EIO;
+		goto out;
+	}
+	err = mmb_sync(&UDF_I(inode)->i_metadata_bhs);
+out:
+	brelse(bh);
+	return err;
+}
+
 static int udf_sync_inode(struct inode *inode)
 {
 	return udf_update_inode(inode, 1);
@@ -1732,7 +1758,6 @@ static int udf_update_inode(struct inode *inode, int do_sync)
 	uint32_t udfperms;
 	uint16_t icbflags;
 	uint16_t crclen;
-	int err = 0;
 	struct udf_sb_info *sbi = UDF_SB(inode->i_sb);
 	unsigned char blocksize_bits = inode->i_sb->s_blocksize_bits;
 	struct udf_inode_info *iinfo = UDF_I(inode);
@@ -1937,17 +1962,10 @@ static int udf_update_inode(struct inode *inode, int do_sync)
 
 	/* write the data blocks */
 	mark_buffer_dirty(bh);
-	if (do_sync) {
-		sync_dirty_buffer(bh);
-		if (buffer_write_io_error(bh)) {
-			udf_warn(inode->i_sb, "IO error syncing udf inode [%08llx]\n",
-				 inode->i_ino);
-			err = -EIO;
-		}
-	}
 	brelse(bh);
+	set_inode_metadata_writeback(inode);
 
-	return err;
+	return 0;
 }
 
 struct inode *__udf_iget(struct super_block *sb, struct kernel_lb_addr *ino,

fs/udf/super.c

@@ -211,6 +211,7 @@ static const struct super_operations udf_sb_ops = {
 	.alloc_inode	= udf_alloc_inode,
 	.free_inode	= udf_free_in_core_inode,
 	.write_inode	= udf_write_inode,
+	.sync_inode_metadata = udf_sync_inode_metadata,
 	.evict_inode	= udf_evict_inode,
 	.put_super	= udf_put_super,
 	.sync_fs	= udf_sync_fs,

fs/udf/udfdecl.h

@@ -137,7 +137,6 @@ static inline unsigned int udf_dir_entry_len(struct fileIdentDesc *cfi)
 
 /* file.c */
 extern long udf_ioctl(struct file *, unsigned int, unsigned long);
-int udf_fsync(struct file *file, loff_t start, loff_t end, int datasync);
 
 /* inode.c */
 extern struct inode *__udf_iget(struct super_block *, struct kernel_lb_addr *,
@@ -158,6 +157,7 @@ extern struct buffer_head *udf_bread(struct inode *inode, udf_pblk_t block,
 extern int udf_setsize(struct inode *, loff_t);
 extern void udf_evict_inode(struct inode *);
 extern int udf_write_inode(struct inode *, struct writeback_control *wbc);
+int udf_sync_inode_metadata(struct inode *, struct writeback_control *wbc);
 extern int inode_bmap(struct inode *inode, sector_t block,
 		      struct extent_position *pos, struct kernel_lb_addr *eloc,
 		      uint32_t *elen, sector_t *offset, int8_t *etype);