exfat: do not fallback to buffered write

After commit(11a347f exfat: change to get file size from
DataLength), the remaining area or hole had been filled with
zeros before calling exfat_direct_IO(), so there is no need to
fallback to buffered write, and ->i_size_aligned is no longer
needed, drop it.

Signed-off-by: Yuezhang Mo <Yuezhang.Mo@sony.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>

Author: YuezhangMo

fs/exfat/exfat_fs.h

@@ -309,8 +309,6 @@ struct exfat_inode_info {
 	/* for avoiding the race between alloc and free */
 	unsigned int cache_valid_id;
 
-	/* block-aligned i_size (used in cont_write_begin) */
-	loff_t i_size_aligned;
 	/* on-disk position of directory entry or 0 */
 	loff_t i_pos;
 	loff_t valid_size;

fs/exfat/file.c

@@ -74,7 +74,6 @@ static int exfat_cont_expand(struct inode *inode, loff_t size)
 	/* Expanded range not zeroed, do not update valid_size */
 	i_size_write(inode, size);
 
-	ei->i_size_aligned = round_up(size, sb->s_blocksize);
 	inode->i_blocks = round_up(size, sbi->cluster_size) >> 9;
 	mark_inode_dirty(inode);
 
@@ -244,8 +243,6 @@ void exfat_truncate(struct inode *inode)
 	struct super_block *sb = inode->i_sb;
 	struct exfat_sb_info *sbi = EXFAT_SB(sb);
 	struct exfat_inode_info *ei = EXFAT_I(inode);
-	unsigned int blocksize = i_blocksize(inode);
-	loff_t aligned_size;
 	int err;
 
 	mutex_lock(&sbi->s_lock);
@@ -263,14 +260,6 @@ void exfat_truncate(struct inode *inode)
 
 	inode->i_blocks = round_up(i_size_read(inode), sbi->cluster_size) >> 9;
 write_size:
-	aligned_size = i_size_read(inode);
-	if (aligned_size & (blocksize - 1)) {
-		aligned_size |= (blocksize - 1);
-		aligned_size++;
-	}
-
-	if (ei->i_size_aligned > i_size_read(inode))
-		ei->i_size_aligned = aligned_size;
 	mutex_unlock(&sbi->s_lock);
 }
 

fs/exfat/inode.c

@@ -258,21 +258,6 @@ static int exfat_map_cluster(struct inode *inode, unsigned int clu_offset,
 	return 0;
 }
 
-static int exfat_map_new_buffer(struct exfat_inode_info *ei,
-		struct buffer_head *bh, loff_t pos)
-{
-	if (buffer_delay(bh) && pos > ei->i_size_aligned)
-		return -EIO;
-	set_buffer_new(bh);
-
-	/*
-	 * Adjust i_size_aligned if ondisk_size is bigger than it.
-	 */
-	if (exfat_ondisk_size(&ei->vfs_inode) > ei->i_size_aligned)
-		ei->i_size_aligned = exfat_ondisk_size(&ei->vfs_inode);
-	return 0;
-}
-
 static int exfat_get_block(struct inode *inode, sector_t iblock,
 		struct buffer_head *bh_result, int create)
 {
@@ -286,7 +271,6 @@ static int exfat_get_block(struct inode *inode, sector_t iblock,
 	sector_t last_block;
 	sector_t phys = 0;
 	sector_t valid_blks;
-	loff_t pos;
 
 	mutex_lock(&sbi->s_lock);
 	last_block = EXFAT_B_TO_BLK_ROUND_UP(i_size_read(inode), sb);
@@ -314,8 +298,6 @@ static int exfat_get_block(struct inode *inode, sector_t iblock,
 	mapped_blocks = sbi->sect_per_clus - sec_offset;
 	max_blocks = min(mapped_blocks, max_blocks);
 
-	pos = EXFAT_BLK_TO_B((iblock + 1), sb);
-
 	map_bh(bh_result, sb, phys);
 	if (buffer_delay(bh_result))
 		clear_buffer_delay(bh_result);
@@ -336,13 +318,7 @@ static int exfat_get_block(struct inode *inode, sector_t iblock,
 		}
 
 		/* The area has not been written, map and mark as new. */
-		err = exfat_map_new_buffer(ei, bh_result, pos);
-		if (err) {
-			exfat_fs_error(sb,
-					"requested for bmap out of range(pos : (%llu) > i_size_aligned(%llu)\n",
-					pos, ei->i_size_aligned);
-			goto unlock_ret;
-		}
+		set_buffer_new(bh_result);
 
 		ei->valid_size = EXFAT_BLK_TO_B(iblock + max_blocks, sb);
 		mark_inode_dirty(inode);
@@ -365,7 +341,7 @@ static int exfat_get_block(struct inode *inode, sector_t iblock,
 			 * The block has been partially written,
 			 * zero the unwritten part and map the block.
 			 */
-			loff_t size, off;
+			loff_t size, off, pos;
 
 			max_blocks = 1;
 
@@ -376,7 +352,7 @@ static int exfat_get_block(struct inode *inode, sector_t iblock,
 			if (!bh_result->b_folio)
 				goto done;
 
-			pos -= sb->s_blocksize;
+			pos = EXFAT_BLK_TO_B(iblock, sb);
 			size = ei->valid_size - pos;
 			off = pos & (PAGE_SIZE - 1);
 
@@ -463,14 +439,6 @@ static int exfat_write_end(struct file *file, struct address_space *mapping,
 	int err;
 
 	err = generic_write_end(file, mapping, pos, len, copied, folio, fsdata);
-
-	if (ei->i_size_aligned < i_size_read(inode)) {
-		exfat_fs_error(inode->i_sb,
-			"invalid size(size(%llu) > aligned(%llu)\n",
-			i_size_read(inode), ei->i_size_aligned);
-		return -EIO;
-	}
-
 	if (err < len)
 		exfat_write_failed(mapping, pos+len);
 
@@ -498,20 +466,6 @@ static ssize_t exfat_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
 	int rw = iov_iter_rw(iter);
 	ssize_t ret;
 
-	if (rw == WRITE) {
-		/*
-		 * FIXME: blockdev_direct_IO() doesn't use ->write_begin(),
-		 * so we need to update the ->i_size_aligned to block boundary.
-		 *
-		 * But we must fill the remaining area or hole by nul for
-		 * updating ->i_size_aligned
-		 *
-		 * Return 0, and fallback to normal buffered write.
-		 */
-		if (EXFAT_I(inode)->i_size_aligned < size)
-			return 0;
-	}
-
 	/*
 	 * Need to use the DIO_LOCKING for avoiding the race
 	 * condition of exfat_get_block() and ->truncate().
@@ -525,8 +479,18 @@ static ssize_t exfat_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
 	} else
 		size = pos + ret;
 
-	/* zero the unwritten part in the partially written block */
-	if (rw == READ && pos < ei->valid_size && ei->valid_size < size) {
+	if (rw == WRITE) {
+		/*
+		 * If the block had been partially written before this write,
+		 * ->valid_size will not be updated in exfat_get_block(),
+		 * update it here.
+		 */
+		if (ei->valid_size < size) {
+			ei->valid_size = size;
+			mark_inode_dirty(inode);
+		}
+	} else if (pos < ei->valid_size && ei->valid_size < size) {
+		/* zero the unwritten part in the partially written block */
 		iov_iter_revert(iter, size - ei->valid_size);
 		iov_iter_zero(size - ei->valid_size, iter);
 	}
@@ -661,14 +625,6 @@ static int exfat_fill_inode(struct inode *inode, struct exfat_dir_entry *info)
 
 	i_size_write(inode, size);
 
-	/* ondisk and aligned size should be aligned with block size */
-	if (size & (inode->i_sb->s_blocksize - 1)) {
-		size |= (inode->i_sb->s_blocksize - 1);
-		size++;
-	}
-
-	ei->i_size_aligned = size;
-
 	exfat_save_attr(inode, info->attr);
 
 	inode->i_blocks = round_up(i_size_read(inode), sbi->cluster_size) >> 9;

fs/exfat/namei.c

@@ -372,7 +372,6 @@ static int exfat_find_empty_entry(struct inode *inode,
 
 		/* directory inode should be updated in here */
 		i_size_write(inode, size);
-		ei->i_size_aligned += sbi->cluster_size;
 		ei->valid_size += sbi->cluster_size;
 		ei->flags = p_dir->flags;
 		inode->i_blocks += sbi->cluster_size >> 9;

fs/exfat/super.c

@@ -370,7 +370,6 @@ static int exfat_read_root(struct inode *inode)
 
 	inode->i_blocks = round_up(i_size_read(inode), sbi->cluster_size) >> 9;
 	ei->i_pos = ((loff_t)sbi->root_dir << 32) | 0xffffffff;
-	ei->i_size_aligned = i_size_read(inode);
 
 	exfat_save_attr(inode, EXFAT_ATTR_SUBDIR);
 	ei->i_crtime = simple_inode_init_ts(inode);