ext4: fix ext4_ext_direct_IO()'s return value after converting uninit extents (109f5565) · Commits · 戴 / test

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>

fs/ext4/extents.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -3519,6 +3519,7 @@ retry:
		*
		* 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)

fs/ext4/inode.c

+7 −3

Original line number	Diff line number	Diff line
		@@ -3772,13 +3772,17 @@ static ssize_t ext4_ext_direct_IO(int rw, struct kiocb *iocb,
		if (ret != -EIOCBQUEUED && ret <= 0 && iocb->private) {
		ext4_free_io_end(iocb->private);
		iocb->private = NULL;
		} else if (ret > 0)
		} else if (ret > 0) {
		int err;
		/*
		* for non AIO case, since the IO is already
		* completed, we could do the convertion right here
		*/
		ret = ext4_convert_unwritten_extents(inode,
		err = ext4_convert_unwritten_extents(inode,
		offset, ret);
		if (err < 0)
		ret = err;
		}
		return ret;
		}

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