Commit 1b43ef91 authored by Andrew Morton's avatar Andrew Morton Committed by Linus Torvalds
Browse files

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: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent c986d1e2

fs/fs-writeback.c

+11 −4
Original line number Diff line number Diff line
@@ -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) {

			/*

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