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

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This reverts commit c9af9fb68e.

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: Sage Weil <sage@newdream.net>
This commit is contained in:
Sage Weil 2011-08-24 14:07:01 -07:00
parent 80db8bea6a
commit 83eaea22bd
1 changed files with 1 additions and 45 deletions
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46
fs/ceph/inode.c
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@ -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 &&