diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
index bcc7831d03af..54dc27d92781 100644
--- a/fs/iomap/buffered-io.c
+++ b/fs/iomap/buffered-io.c
@@ -1794,7 +1794,52 @@ static int iomap_add_to_ioend(struct iomap_writepage_ctx *wpc,
 
 	if (ifs)
 		atomic_add(len, &ifs->write_bytes_pending);
+
+	/*
+	 * Clamp io_offset and io_size to the incore EOF so that ondisk
+	 * file size updates in the ioend completion are byte-accurate.
+	 * This avoids recovering files with zeroed tail regions when
+	 * writeback races with appending writes:
+	 *
+	 *    Thread 1:                  Thread 2:
+	 *    ------------               -----------
+	 *    write [A, A+B]
+	 *    update inode size to A+B
+	 *    submit I/O [A, A+BS]
+	 *                               write [A+B, A+B+C]
+	 *                               update inode size to A+B+C
+	 *    <I/O completes, updates disk size to min(A+B+C, A+BS)>
+	 *    <power failure>
+	 *
+	 *  After reboot:
+	 *    1) with A+B+C < A+BS, the file has zero padding in range
+	 *       [A+B, A+B+C]
+	 *
+	 *    |<     Block Size (BS)   >|
+	 *    |DDDDDDDDDDDD0000000000000|
+	 *    ^           ^        ^
+	 *    A          A+B     A+B+C
+	 *                       (EOF)
+	 *
+	 *    2) with A+B+C > A+BS, the file has zero padding in range
+	 *       [A+B, A+BS]
+	 *
+	 *    |<     Block Size (BS)   >|<     Block Size (BS)    >|
+	 *    |DDDDDDDDDDDD0000000000000|00000000000000000000000000|
+	 *    ^           ^             ^           ^
+	 *    A          A+B           A+BS       A+B+C
+	 *                             (EOF)
+	 *
+	 *    D = Valid Data
+	 *    0 = Zero Padding
+	 *
+	 * Note that this defeats the ability to chain the ioends of
+	 * appending writes.
+	 */
 	wpc->ioend->io_size += len;
+	if (wpc->ioend->io_offset + wpc->ioend->io_size > end_pos)
+		wpc->ioend->io_size = end_pos - wpc->ioend->io_offset;
+
 	wbc_account_cgroup_owner(wbc, folio, len);
 	return 0;
 }
diff --git a/include/linux/iomap.h b/include/linux/iomap.h
index 5675af6b740c..75bf54e76f3b 100644
--- a/include/linux/iomap.h
+++ b/include/linux/iomap.h
@@ -335,7 +335,7 @@ struct iomap_ioend {
 	u16			io_type;
 	u16			io_flags;	/* IOMAP_F_* */
 	struct inode		*io_inode;	/* file being written to */
-	size_t			io_size;	/* size of the extent */
+	size_t			io_size;	/* size of data within eof */
 	loff_t			io_offset;	/* offset in the file */
 	sector_t		io_sector;	/* start sector of ioend */
 	struct bio		io_bio;		/* MUST BE LAST! */