writeback: fix comment, use helper function

There's a comment in there which claims that the inode is left on s_io
if nfs chickened out of writing some data.

But that's not been true for three years.
9290280ced13c85689adeffa587e9a53bd3a5873 fixed a livelock by moving these
inodes back onto s_dirty.  Fix the comment.

In the second leg of the `if', use redirty_tail() rather than open-coding it.

Add weaselly comment indicating lack of confidence in the code and lack of the
fortitude which would be needed to fiddle with it.

Cc: Mike Waychison <mikew@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Andrew Morton 2007-10-16 23:30:35 -07:00 committed by Linus Torvalds
parent c986d1e2a4
commit 1b43ef91d4

View File

@ -201,7 +201,6 @@ __sync_single_inode(struct inode *inode, struct writeback_control *wbc)
{
unsigned dirty;
struct address_space *mapping = inode->i_mapping;
struct super_block *sb = inode->i_sb;
int wait = wbc->sync_mode == WB_SYNC_ALL;
int ret;
@ -237,7 +236,16 @@ __sync_single_inode(struct inode *inode, struct writeback_control *wbc)
/*
* We didn't write back all the pages. nfs_writepages()
* sometimes bales out without doing anything. Redirty
* the inode. It is still on sb->s_io.
* the inode. It is moved from s_io onto s_dirty.
*/
/*
* akpm: if the caller was the kupdate function we put
* this inode at the head of s_dirty so it gets first
* consideration. Otherwise, move it to the tail, for
* the reasons described there. I'm not really sure
* how much sense this makes. Presumably I had a good
* reasons for doing it this way, and I'd rather not
* muck with it at present.
*/
if (wbc->for_kupdate) {
/*
@ -257,8 +265,7 @@ __sync_single_inode(struct inode *inode, struct writeback_control *wbc)
* all the other files.
*/
inode->i_state |= I_DIRTY_PAGES;
inode->dirtied_when = jiffies;
list_move(&inode->i_list, &sb->s_dirty);
redirty_tail(inode);
}
} else if (inode->i_state & I_DIRTY) {
/*