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Commit 6298a337 authored by Sage Weil's avatar Sage Weil
Browse files

ceph: fix snap context reference leaks 



The get_oldest_context() helper takes a reference to the returned snap
context, but most callers weren't dropping that reference.  Fix them.

Also drop the unused locked __get_oldest_context() variant.

Signed-off-by: default avatarSage Weil <sage@newdream.net>
parent 80e755fe

fs/ceph/addr.c

+17 −20
Original line number Diff line number Diff line
@@ -336,16 +336,15 @@ static int ceph_readpages(struct file *file, struct address_space *mapping, 
/*

 * Get ref for the oldest snapc for an inode with dirty data... that is, the

 * only snap context we are allowed to write back.

 *

 * Caller holds i_lock.

 */

static struct ceph_snap_context *__get_oldest_context(struct inode *inode,

static struct ceph_snap_context *get_oldest_context(struct inode *inode,

						    u64 *snap_size)

{

	struct ceph_inode_info *ci = ceph_inode(inode);

	struct ceph_snap_context *snapc = NULL;

	struct ceph_cap_snap *capsnap = NULL;



	spin_lock(&inode->i_lock);

	list_for_each_entry(capsnap, &ci->i_cap_snaps, ci_item) {

		dout(" cap_snap %p snapc %p has %d dirty pages\n", capsnap,

		     capsnap->context, capsnap->dirty_pages);
@@ -361,16 +360,6 @@ static struct ceph_snap_context *__get_oldest_context(struct inode *inode, 
		dout(" head snapc %p has %d dirty pages\n",

		     snapc, ci->i_wrbuffer_ref_head);

	}

	return snapc;

}



static struct ceph_snap_context *get_oldest_context(struct inode *inode,

						    u64 *snap_size)

{

	struct ceph_snap_context *snapc = NULL;



	spin_lock(&inode->i_lock);

	snapc = __get_oldest_context(inode, snap_size);

	spin_unlock(&inode->i_lock);

	return snapc;

}
@@ -391,7 +380,7 @@ static int writepage_nounlock(struct page *page, struct writeback_control *wbc) 
	int len = PAGE_CACHE_SIZE;

	loff_t i_size;

	int err = 0;

	struct ceph_snap_context *snapc;

	struct ceph_snap_context *snapc, *oldest;

	u64 snap_size = 0;

	long writeback_stat;
@@ -412,13 +401,16 @@ static int writepage_nounlock(struct page *page, struct writeback_control *wbc) 
		dout("writepage %p page %p not dirty?\n", inode, page);

		goto out;

	}

	if (snapc->seq > get_oldest_context(inode, &snap_size)->seq) {

	oldest = get_oldest_context(inode, &snap_size);

	if (snapc->seq > oldest->seq) {

		dout("writepage %p page %p snapc %p not writeable - noop\n",

		     inode, page, (void *)page->private);

		/* we should only noop if called by kswapd */

		WARN_ON((current->flags & PF_MEMALLOC) == 0);

		ceph_put_snap_context(oldest);

		goto out;

	}

	ceph_put_snap_context(oldest);



	/* is this a partial page at end of file? */

	if (snap_size)
@@ -457,7 +449,7 @@ static int writepage_nounlock(struct page *page, struct writeback_control *wbc) 
	ClearPagePrivate(page);

	end_page_writeback(page);

	ceph_put_wrbuffer_cap_refs(ci, 1, snapc);

	ceph_put_snap_context(snapc);

	ceph_put_snap_context(snapc);  /* page's reference */

out:

	return err;

}
@@ -914,7 +906,10 @@ static int context_is_writeable_or_written(struct inode *inode, 
					   struct ceph_snap_context *snapc)

{

	struct ceph_snap_context *oldest = get_oldest_context(inode, NULL);

	return !oldest || snapc->seq <= oldest->seq;

	int ret = !oldest || snapc->seq <= oldest->seq;



	ceph_put_snap_context(oldest);

	return ret;

}



/*
@@ -957,13 +952,14 @@ static int ceph_update_writeable_page(struct file *file, 
		up_read(&mdsc->snap_rwsem);



		if (snapc->seq > oldest->seq) {

			ceph_put_snap_context(oldest);

			dout(" page %p snapc %p not current or oldest\n",

			     page, (void *)page->private);

			     page, snapc);

			/*

			 * queue for writeback, and wait for snapc to

			 * be writeable or written

			 */

			snapc = ceph_get_snap_context((void *)page->private);

			snapc = ceph_get_snap_context(snapc);

			unlock_page(page);

			ceph_queue_writeback(inode);

			r = wait_event_interruptible(ci->i_cap_wq,
@@ -973,6 +969,7 @@ static int ceph_update_writeable_page(struct file *file, 
				return r;

			return -EAGAIN;

		}

		ceph_put_snap_context(oldest);



		/* yay, writeable, do it now (without dropping page lock) */

		dout(" page %p snapc %p not current, but oldest\n",