f2fs: update several comments
Update several comments:
1. use f2fs_{un}lock_op install of mutex_{un}lock_op.
2. update comment of get_data_block().
3. update description of node offset.
Signed-off-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index e46b5c5..0879d2a 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -508,8 +508,8 @@
* Caller ensures that this data page is never allocated.
* A new zero-filled data page is allocated in the page cache.
*
- * Also, caller should grab and release a mutex by calling mutex_lock_op() and
- * mutex_unlock_op().
+ * Also, caller should grab and release a rwsem by calling f2fs_lock_op() and
+ * f2fs_unlock_op().
* Note that, npage is set only by make_empty_dir.
*/
struct page *get_new_data_page(struct inode *inode,
@@ -595,10 +595,12 @@
}
/*
- * This function should be used by the data read flow only where it
- * does not check the "create" flag that indicates block allocation.
- * The reason for this special functionality is to exploit VFS readahead
- * mechanism.
+ * get_data_block() now supported readahead/bmap/rw direct_IO with mapped bh.
+ * If original data blocks are allocated, then give them to blockdev.
+ * Otherwise,
+ * a. preallocate requested block addresses
+ * b. do not use extent cache for better performance
+ * c. give the block addresses to blockdev
*/
static int get_data_block(struct inode *inode, sector_t iblock,
struct buffer_head *bh_result, int create)