ext4: fix ext4_ext_direct_IO()'s return value after converting uninit extents
After a direct I/O request covering an uninitalized extent (i.e.,
created using the fallocate system call) or a hole in a file, ext4
will convert the uninitialized extent so it is marked as initialized
by calling ext4_convert_unwritten_extents(). This function returns
zero on success.
This return value was getting returned by ext4_direct_IO(); however
the file system's direct_IO function is supposed to return the number
of bytes read or written on a success. By returning zero, it confused
the direct I/O code into falling back to buffered I/O unnecessarily.
Signed-off-by: Mingming Cao <cmm@us.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index 10539e3..441716f 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -3519,6 +3519,7 @@
*
* This function is called from the direct IO end io call back
* function, to convert the fallocated extents after IO is completed.
+ * Returns 0 on success.
*/
int ext4_convert_unwritten_extents(struct inode *inode, loff_t offset,
loff_t len)