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-rw-r--r--fs/ext4/file.c25
1 files changed, 21 insertions, 4 deletions
diff --git a/fs/ext4/file.c b/fs/ext4/file.c
index 194f5d00fa32..7924634ab0bf 100644
--- a/fs/ext4/file.c
+++ b/fs/ext4/file.c
@@ -371,15 +371,32 @@ truncate:
static int ext4_dio_write_end_io(struct kiocb *iocb, ssize_t size,
int error, unsigned int flags)
{
- loff_t offset = iocb->ki_pos;
+ loff_t pos = iocb->ki_pos;
struct inode *inode = file_inode(iocb->ki_filp);
if (error)
return error;
- if (size && flags & IOMAP_DIO_UNWRITTEN)
- return ext4_convert_unwritten_extents(NULL, inode,
- offset, size);
+ if (size && flags & IOMAP_DIO_UNWRITTEN) {
+ error = ext4_convert_unwritten_extents(NULL, inode, pos, size);
+ if (error < 0)
+ return error;
+ }
+ /*
+ * If we are extending the file, we have to update i_size here before
+ * page cache gets invalidated in iomap_dio_rw(). Otherwise racing
+ * buffered reads could zero out too much from page cache pages. Update
+ * of on-disk size will happen later in ext4_dio_write_iter() where
+ * we have enough information to also perform orphan list handling etc.
+ * Note that we perform all extending writes synchronously under
+ * i_rwsem held exclusively so i_size update is safe here in that case.
+ * If the write was not extending, we cannot see pos > i_size here
+ * because operations reducing i_size like truncate wait for all
+ * outstanding DIO before updating i_size.
+ */
+ pos += size;
+ if (pos > i_size_read(inode))
+ i_size_write(inode, pos);
return 0;
}