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ext4: delete useless comments about ext4_move_extents

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In patch 'ext4: refactor ext4_move_extents code base',  Dmitry Monakhov has
refactored ext4_move_extents' implementation, but forgot to update the
corresponding comments, this patch will try to delete some useless comments.

Reviewed-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: Xiaoguang Wang <wangxg.fnst@cn.fujitsu.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
This commit is contained in:
Xiaoguang Wang 2014-10-11 19:56:34 -04:00 committed by Theodore Ts'o
parent 0ff8947fc5
commit 65dd8327eb
1 changed files with 6 additions and 53 deletions
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59
fs/ext4/move_extent.c
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@ -119,34 +119,13 @@ out:
return ret;
}
/**
* mext_replace_branches - Replace original extents with new extents
*
* @handle: journal handle
* @orig_inode: original inode
* @donor_inode: donor inode
* @from: block offset of orig_inode
* @count: block count to be replaced
* @err: pointer to save return value
*
* Replace original inode extents and donor inode extents page by page.
* We implement this replacement in the following three steps:
* 1. Save the block information of original and donor inodes into
* dummy extents.
* 2. Change the block information of original inode to point at the
* donor inode blocks.
* 3. Change the block information of donor inode to point at the saved
* original inode blocks in the dummy extents.
*
* Return replaced block count.
*/
/**
* mext_page_double_lock - Grab and lock pages on both @inode1 and @inode2
*
* @inode1: the inode structure
* @inode2: the inode structure
* @index: page index
* @index1: page index
* @index2: page index
* @page: result page vector
*
* Grab two locked pages for inode's by inode order
@ -266,13 +245,14 @@ out:
* @o_filp: file structure of original file
* @donor_inode: donor inode
* @orig_page_offset: page index on original file
* @donor_page_offset: page index on donor file
* @data_offset_in_page: block index where data swapping starts
* @block_len_in_page: the number of blocks to be swapped
* @unwritten: orig extent is unwritten or not
* @err: pointer to save return value
*
* Save the data in original inode blocks and replace original inode extents
* with donor inode extents by calling mext_replace_branches().
* with donor inode extents by calling ext4_swap_extents().
* Finally, write out the saved data in new original inode blocks. Return
* replaced block count.
*/
@ -551,41 +531,14 @@ mext_check_arguments(struct inode *orig_inode,
*
* @o_filp: file structure of the original file
* @d_filp: file structure of the donor file
* @orig_start: start offset in block for orig
* @donor_start: start offset in block for donor
* @orig_blk: start offset in block for orig
* @donor_blk: start offset in block for donor
* @len: the number of blocks to be moved
* @moved_len: moved block length
*
* This function returns 0 and moved block length is set in moved_len
* if succeed, otherwise returns error value.
*
* Note: ext4_move_extents() proceeds the following order.
* 1:ext4_move_extents() calculates the last block number of moving extent
* function by the start block number (orig_start) and the number of blocks
* to be moved (len) specified as arguments.
* If the {orig, donor}_start points a hole, the extent's start offset
* pointed by ext_cur (current extent), holecheck_path, orig_path are set
* after hole behind.
* 2:Continue step 3 to step 5, until the holecheck_path points to last_extent
* or the ext_cur exceeds the block_end which is last logical block number.
* 3:To get the length of continues area, call mext_next_extent()
* specified with the ext_cur (initial value is holecheck_path) re-cursive,
* until find un-continuous extent, the start logical block number exceeds
* the block_end or the extent points to the last extent.
* 4:Exchange the original inode data with donor inode data
* from orig_page_offset to seq_end_page.
* The start indexes of data are specified as arguments.
* That of the original inode is orig_page_offset,
* and the donor inode is also orig_page_offset
* (To easily handle blocksize != pagesize case, the offset for the
* donor inode is block unit).
* 5:Update holecheck_path and orig_path to points a next proceeding extent,
* then returns to step 2.
* 6:Release holecheck_path, orig_path and set the len to moved_len
* which shows the number of moved blocks.
* The moved_len is useful for the command to calculate the file offset
* for starting next move extent ioctl.
* 7:Return 0 on success, or a negative error value on failure.
*/
int
ext4_move_extents(struct file *o_filp, struct file *d_filp, __u64 orig_blk,