1 files changed, 25 insertions, 6 deletions

diff --git a/fs/ext4/file.c b/fs/ext4/file.c
index 5f225881176b..7d61069531d3 100644
--- a/fs/ext4/file.c
+++ b/fs/ext4/file.c
@@ -145,10 +145,9 @@ static int ext4_release_file(struct inode *inode, struct file *filp)
 	/* if we are the last writer on the inode, drop the block reservation */
 	if ((filp->f_mode & FMODE_WRITE) &&
 			(atomic_read(&inode->i_writecount) == 1) &&
-		        !EXT4_I(inode)->i_reserved_data_blocks)
-	{
+			!EXT4_I(inode)->i_reserved_data_blocks) {
 		down_write(&EXT4_I(inode)->i_data_sem);
-		ext4_discard_preallocations(inode);
+		ext4_discard_preallocations(inode, 0);
 		up_write(&EXT4_I(inode)->i_data_sem);
 	}
 	if (is_dx(inode) && filp->private_data)
@@ -287,6 +286,7 @@ static ssize_t ext4_handle_inode_extension(struct inode *inode, loff_t offset,
 	bool truncate = false;
 	u8 blkbits = inode->i_blkbits;
 	ext4_lblk_t written_blk, end_blk;
+	int ret;
 
 	/*
 	 * Note that EXT4_I(inode)->i_disksize can get extended up to
@@ -327,8 +327,14 @@ static ssize_t ext4_handle_inode_extension(struct inode *inode, loff_t offset,
 		goto truncate;
 	}
 
-	if (ext4_update_inode_size(inode, offset + written))
-		ext4_mark_inode_dirty(handle, inode);
+	if (ext4_update_inode_size(inode, offset + written)) {
+		ret = ext4_mark_inode_dirty(handle, inode);
+		if (unlikely(ret)) {
+			written = ret;
+			ext4_journal_stop(handle);
+			goto truncate;
+		}
+	}
 
 	/*
 	 * We may need to truncate allocated but not written blocks beyond EOF.
@@ -421,6 +427,10 @@ restart:
 	 */
 	if (*ilock_shared && (!IS_NOSEC(inode) || *extend ||
 	     !ext4_overwrite_io(inode, offset, count))) {
+		if (iocb->ki_flags & IOCB_NOWAIT) {
+			ret = -EAGAIN;
+			goto out;
+		}
 		inode_unlock_shared(inode);
 		*ilock_shared = false;
 		inode_lock(inode);
@@ -495,6 +505,12 @@ static ssize_t ext4_dio_write_iter(struct kiocb *iocb, struct iov_iter *from)
 	if (ret <= 0)
 		return ret;
 
+	/* if we're going to block and IOCB_NOWAIT is set, return -EAGAIN */
+	if ((iocb->ki_flags & IOCB_NOWAIT) && (unaligned_io || extend)) {
+		ret = -EAGAIN;
+		goto out;
+	}
+
 	offset = iocb->ki_pos;
 	count = ret;
 
@@ -531,6 +547,8 @@ static ssize_t ext4_dio_write_iter(struct kiocb *iocb, struct iov_iter *from)
 		iomap_ops = &ext4_iomap_overwrite_ops;
 	ret = iomap_dio_rw(iocb, from, iomap_ops, &ext4_dio_write_ops,
 			   is_sync_kiocb(iocb) || unaligned_io || extend);
+	if (ret == -ENOTBLK)
+		ret = 0;
 
 	if (extend)
 		ret = ext4_handle_inode_extension(inode, offset, ret, count);
@@ -797,7 +815,7 @@ out:
 	return err;
 }
 
-static int ext4_file_open(struct inode * inode, struct file * filp)
+static int ext4_file_open(struct inode *inode, struct file *filp)
 {
 	int ret;
 
@@ -872,6 +890,7 @@ const struct file_operations ext4_file_operations = {
 	.llseek		= ext4_llseek,
 	.read_iter	= ext4_file_read_iter,
 	.write_iter	= ext4_file_write_iter,
+	.iopoll		= iomap_dio_iopoll,
 	.unlocked_ioctl = ext4_ioctl,
 #ifdef CONFIG_COMPAT
 	.compat_ioctl	= ext4_compat_ioctl,