Commit 4188188b authored by Curt Wohlgemuth's avatar Curt Wohlgemuth Committed by Theodore Ts'o
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ext4: add comments to definition of ext4_io_end_t 



This should make it more clear what this structure is used
for, and how some of the (mutually exclusive) fields are
used to keep page cache references.

Signed-off-by: default avatarCurt Wohlgemuth <curtw@google.com>
Signed-off-by: default avatar"Theodore Ts'o" <tytso@mit.edu>
parent b43d17f3

fs/ext4/ext4.h

+10 −3
Original line number Diff line number Diff line
@@ -194,18 +194,25 @@ struct ext4_io_page { 


#define MAX_IO_PAGES 128



/*

 * For converting uninitialized extents on a work queue.

 *

 * 'page' is only used from the writepage() path; 'pages' is only used for

 * buffered writes; they are used to keep page references until conversion

 * takes place.  For AIO/DIO, neither field is filled in.

 */

typedef struct ext4_io_end {

	struct list_head	list;		/* per-file finished IO list */

	struct inode		*inode;		/* file being written to */

	unsigned int		flag;		/* unwritten or not */

	struct page		*page;		/* page struct for buffer write */

	struct page		*page;		/* for writepage() path */

	loff_t			offset;		/* offset in the file */

	ssize_t			size;		/* size of the extent */

	struct work_struct	work;		/* data work queue */

	struct kiocb		*iocb;		/* iocb struct for AIO */

	int			result;		/* error value for AIO */

	int			num_io_pages;

	struct ext4_io_page	*pages[MAX_IO_PAGES];

	int			num_io_pages;   /* for writepages() */

	struct ext4_io_page	*pages[MAX_IO_PAGES]; /* for writepages() */

} ext4_io_end_t;



struct ext4_io_submit {