提交 4188188b 编写于 作者: C Curt Wohlgemuth 提交者: Theodore Ts'o

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: NCurt Wohlgemuth <curtw@google.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>
上级 b43d17f3
......@@ -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 {
......
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