1 files changed, 111 insertions, 130 deletions

diff --git a/fs/exfat/inode.c b/fs/exfat/inode.c
index dd894e558c91..b22c02d6000f 100644
--- a/fs/exfat/inode.c
+++ b/fs/exfat/inode.c
@@ -43,7 +43,7 @@ int __exfat_write_inode(struct inode *inode, int sync)
 	exfat_set_volume_dirty(sb);
 
 	/* get the directory entry of given file or directory */
-	if (exfat_get_dentry_set(&es, sb, &(ei->dir), ei->entry, ES_ALL_ENTRIES))
+	if (exfat_get_dentry_set_by_ei(&es, sb, ei))
 		return -EIO;
 	ep = exfat_get_dentry_cached(&es, ES_IDX_FILE);
 	ep2 = exfat_get_dentry_cached(&es, ES_IDX_STREAM);
@@ -102,6 +102,9 @@ int exfat_write_inode(struct inode *inode, struct writeback_control *wbc)
 {
 	int ret;
 
+	if (unlikely(exfat_forced_shutdown(inode->i_sb)))
+		return -EIO;
+
 	mutex_lock(&EXFAT_SB(inode->i_sb)->s_lock);
 	ret = __exfat_write_inode(inode, wbc->sync_mode == WB_SYNC_ALL);
 	mutex_unlock(&EXFAT_SB(inode->i_sb)->s_lock);
@@ -130,11 +133,9 @@ static int exfat_map_cluster(struct inode *inode, unsigned int clu_offset,
 	struct exfat_sb_info *sbi = EXFAT_SB(sb);
 	struct exfat_inode_info *ei = EXFAT_I(inode);
 	unsigned int local_clu_offset = clu_offset;
-	unsigned int num_to_be_allocated = 0, num_clusters = 0;
+	unsigned int num_to_be_allocated = 0, num_clusters;
 
-	if (ei->i_size_ondisk > 0)
-		num_clusters =
-			EXFAT_B_TO_CLU_ROUND_UP(ei->i_size_ondisk, sbi);
+	num_clusters = EXFAT_B_TO_CLU(exfat_ondisk_size(inode), sbi);
 
 	if (clu_offset >= num_clusters)
 		num_to_be_allocated = clu_offset - num_clusters + 1;
@@ -260,21 +261,6 @@ 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 i_size_ondisk is bigger than it.
-	 */
-	if (ei->i_size_ondisk > ei->i_size_aligned)
-		ei->i_size_aligned = ei->i_size_ondisk;
-	return 0;
-}
-
 static int exfat_get_block(struct inode *inode, sector_t iblock,
 		struct buffer_head *bh_result, int create)
 {
@@ -288,10 +274,11 @@ 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;
+	loff_t i_size;
 
 	mutex_lock(&sbi->s_lock);
-	last_block = EXFAT_B_TO_BLK_ROUND_UP(i_size_read(inode), sb);
+	i_size = i_size_read(inode);
+	last_block = EXFAT_B_TO_BLK_ROUND_UP(i_size, sb);
 	if (iblock >= last_block && !create)
 		goto done;
 
@@ -316,93 +303,103 @@ 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);
-	if ((create && iblock >= last_block) || buffer_delay(bh_result)) {
-		if (ei->i_size_ondisk < pos)
-			ei->i_size_ondisk = pos;
-	}
-
 	map_bh(bh_result, sb, phys);
 	if (buffer_delay(bh_result))
 		clear_buffer_delay(bh_result);
 
-	if (create) {
+	/*
+	 * In most cases, we just need to set bh_result to mapped, unmapped
+	 * or new status as follows:
+	 *  1. i_size == valid_size
+	 *  2. write case (create == 1)
+	 *  3. direct_read (!bh_result->b_folio)
+	 *     -> the unwritten part will be zeroed in exfat_direct_IO()
+	 *
+	 * Otherwise, in the case of buffered read, it is necessary to take
+	 * care the last nested block if valid_size is not equal to i_size.
+	 */
+	if (i_size == ei->valid_size || create || !bh_result->b_folio)
 		valid_blks = EXFAT_B_TO_BLK_ROUND_UP(ei->valid_size, sb);
+	else
+		valid_blks = EXFAT_B_TO_BLK(ei->valid_size, sb);
 
-		if (iblock + max_blocks < valid_blks) {
-			/* The range has been written, map it */
-			goto done;
-		} else if (iblock < valid_blks) {
-			/*
-			 * The range has been partially written,
-			 * map the written part.
-			 */
-			max_blocks = valid_blks - iblock;
-			goto done;
-		}
+	/* The range has been fully written, map it */
+	if (iblock + max_blocks < valid_blks)
+		goto done;
 
-		/* 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;
-		}
+	/* The range has been partially written, map the written part */
+	if (iblock < valid_blks) {
+		max_blocks = valid_blks - iblock;
+		goto done;
+	}
 
+	/* The area has not been written, map and mark as new for create case */
+	if (create) {
+		set_buffer_new(bh_result);
 		ei->valid_size = EXFAT_BLK_TO_B(iblock + max_blocks, sb);
 		mark_inode_dirty(inode);
-	} else {
-		valid_blks = EXFAT_B_TO_BLK(ei->valid_size, sb);
+		goto done;
+	}
+
+	/*
+	 * The area has just one block partially written.
+	 * In that case, we should read and fill the unwritten part of
+	 * a block with zero.
+	 */
+	if (bh_result->b_folio && iblock == valid_blks &&
+	    (ei->valid_size & (sb->s_blocksize - 1))) {
+		loff_t size, pos;
+		void *addr;
+
+		max_blocks = 1;
 
-		if (iblock + max_blocks < valid_blks) {
-			/* The range has been written, map it */
+		/*
+		 * No buffer_head is allocated.
+		 * (1) bmap: It's enough to set blocknr without I/O.
+		 * (2) read: The unwritten part should be filled with zero.
+		 *           If a folio does not have any buffers,
+		 *           let's returns -EAGAIN to fallback to
+		 *           block_read_full_folio() for per-bh IO.
+		 */
+		if (!folio_buffers(bh_result->b_folio)) {
+			err = -EAGAIN;
 			goto done;
-		} else if (iblock < valid_blks) {
-			/*
-			 * The area has been partially written,
-			 * map the written part.
-			 */
-			max_blocks = valid_blks - iblock;
+		}
+
+		pos = EXFAT_BLK_TO_B(iblock, sb);
+		size = ei->valid_size - pos;
+		addr = folio_address(bh_result->b_folio) +
+			offset_in_folio(bh_result->b_folio, pos);
+
+		/* Check if bh->b_data points to proper addr in folio */
+		if (bh_result->b_data != addr) {
+			exfat_fs_error_ratelimit(sb,
+					"b_data(%p) != folio_addr(%p)",
+					bh_result->b_data, addr);
+			err = -EINVAL;
 			goto done;
-		} else if (iblock == valid_blks &&
-			   (ei->valid_size & (sb->s_blocksize - 1))) {
-			/*
-			 * The block has been partially written,
-			 * zero the unwritten part and map the block.
-			 */
-			loff_t size, off;
-
-			max_blocks = 1;
-
-			/*
-			 * For direct read, the unwritten part will be zeroed in
-			 * exfat_direct_IO()
-			 */
-			if (!bh_result->b_folio)
-				goto done;
-
-			pos -= sb->s_blocksize;
-			size = ei->valid_size - pos;
-			off = pos & (PAGE_SIZE - 1);
-
-			folio_set_bh(bh_result, bh_result->b_folio, off);
-			err = bh_read(bh_result, 0);
-			if (err < 0)
-				goto unlock_ret;
-
-			folio_zero_segment(bh_result->b_folio, off + size,
-					off + sb->s_blocksize);
-		} else {
-			/*
-			 * The range has not been written, clear the mapped flag
-			 * to only zero the cache and do not read from disk.
-			 */
-			clear_buffer_mapped(bh_result);
 		}
+
+		/* Read a block */
+		err = bh_read(bh_result, 0);
+		if (err < 0)
+			goto done;
+
+		/* Zero unwritten part of a block */
+		memset(bh_result->b_data + size, 0, bh_result->b_size - size);
+		err = 0;
+		goto done;
 	}
+
+	/*
+	 * The area has not been written, clear mapped for read/bmap cases.
+	 * If so, it will be filled with zero without reading from disk.
+	 */
+	clear_buffer_mapped(bh_result);
 done:
 	bh_result->b_size = EXFAT_BLK_TO_B(max_blocks, sb);
+	if (err < 0)
+		clear_buffer_mapped(bh_result);
 unlock_ret:
 	mutex_unlock(&sbi->s_lock);
 	return err;
@@ -432,6 +429,9 @@ static void exfat_readahead(struct readahead_control *rac)
 static int exfat_writepages(struct address_space *mapping,
 		struct writeback_control *wbc)
 {
+	if (unlikely(exfat_forced_shutdown(mapping->host->i_sb)))
+		return -EIO;
+
 	return mpage_writepages(mapping, wbc, exfat_get_block);
 }
 
@@ -448,12 +448,14 @@ static void exfat_write_failed(struct address_space *mapping, loff_t to)
 
 static int exfat_write_begin(struct file *file, struct address_space *mapping,
 		loff_t pos, unsigned int len,
-		struct page **pagep, void **fsdata)
+		struct folio **foliop, void **fsdata)
 {
 	int ret;
 
-	*pagep = NULL;
-	ret = block_write_begin(mapping, pos, len, pagep, exfat_get_block);
+	if (unlikely(exfat_forced_shutdown(mapping->host->i_sb)))
+		return -EIO;
+
+	ret = block_write_begin(mapping, pos, len, foliop, exfat_get_block);
 
 	if (ret < 0)
 		exfat_write_failed(mapping, pos+len);
@@ -463,21 +465,13 @@ static int exfat_write_begin(struct file *file, struct address_space *mapping,
 
 static int exfat_write_end(struct file *file, struct address_space *mapping,
 		loff_t pos, unsigned int len, unsigned int copied,
-		struct page *pagep, void *fsdata)
+		struct folio *folio, void *fsdata)
 {
 	struct inode *inode = mapping->host;
 	struct exfat_inode_info *ei = EXFAT_I(inode);
 	int err;
 
-	err = generic_write_end(file, mapping, pos, len, copied, pagep, 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;
-	}
-
+	err = generic_write_end(file, mapping, pos, len, copied, folio, fsdata);
 	if (err < len)
 		exfat_write_failed(mapping, pos+len);
 
@@ -505,20 +499,6 @@ 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().
@@ -532,8 +512,18 @@ 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);
 	}
@@ -668,15 +658,6 @@ 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;
-	ei->i_size_ondisk = size;
-
 	exfat_save_attr(inode, info->attr);
 
 	inode->i_blocks = round_up(i_size_read(inode), sbi->cluster_size) >> 9;