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Commit 83eaea22 authored by Sage Weil's avatar Sage Weil
Browse files

Revert "ceph: don't truncate dirty pages in invalidate work thread" 



This reverts commit c9af9fb6.

We need to block and truncate all pages in order to reliably invalidate
them.  Otherwise, we could:

 - have some uptodate pages in the cache
 - queue an invalidate
 - write(2) locks some pages
 - invalidate_work skips them
 - write(2) only overwrites part of the page
 - page now dirty and uptodate
 -> partial leakage of invalidated data

It's not entirely clear why we started skipping locked pages in the first
place.  I just ran this through fsx and didn't see any problems.

Signed-off-by: default avatarSage Weil <sage@newdream.net>
parent 80db8bea

fs/ceph/inode.c

+1 −45
Original line number Diff line number Diff line
@@ -9,7 +9,6 @@ 
#include <linux/namei.h>

#include <linux/writeback.h>

#include <linux/vmalloc.h>

#include <linux/pagevec.h>



#include "super.h"

#include "mds_client.h"
@@ -1363,49 +1362,6 @@ void ceph_queue_invalidate(struct inode *inode) 
	}

}



/*

 * invalidate any pages that are not dirty or under writeback.  this

 * includes pages that are clean and mapped.

 */

static void ceph_invalidate_nondirty_pages(struct address_space *mapping)

{

	struct pagevec pvec;

	pgoff_t next = 0;

	int i;



	pagevec_init(&pvec, 0);

	while (pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)) {

		for (i = 0; i < pagevec_count(&pvec); i++) {

			struct page *page = pvec.pages[i];

			pgoff_t index;

			int skip_page =

				(PageDirty(page) || PageWriteback(page));



			if (!skip_page)

				skip_page = !trylock_page(page);



			/*

			 * We really shouldn't be looking at the ->index of an

			 * unlocked page.  But we're not allowed to lock these

			 * pages.  So we rely upon nobody altering the ->index

			 * of this (pinned-by-us) page.

			 */

			index = page->index;

			if (index > next)

				next = index;

			next++;



			if (skip_page)

				continue;



			generic_error_remove_page(mapping, page);

			unlock_page(page);

		}

		pagevec_release(&pvec);

		cond_resched();

	}

}



/*

 * Invalidate inode pages in a worker thread.  (This can't be done

 * in the message handler context.)
@@ -1429,7 +1385,7 @@ static void ceph_invalidate_work(struct work_struct *work) 
	orig_gen = ci->i_rdcache_gen;

	spin_unlock(&inode->i_lock);



	ceph_invalidate_nondirty_pages(inode->i_mapping);

	truncate_inode_pages(&inode->i_data, 0);



	spin_lock(&inode->i_lock);

	if (orig_gen == ci->i_rdcache_gen &&