Commit 29418aa4 authored by Mel Gorman's avatar Mel Gorman Committed by Linus Torvalds
Browse files

nfs: disable data cache revalidation for swapfiles 

The VM does not like PG_private set on PG_swapcache pages.  As suggested
by Trond in http://lkml.org/lkml/2006/8/25/348

, this patch disables NFS
data cache revalidation on swap files.  as it does not make sense to have
other clients change the file while it is being used as swap.  This avoids
setting PG_private on swap pages, since there ought to be no further races
with invalidate_inode_pages2() to deal with.

Since we cannot set PG_private we cannot use page->private which is
already used by PG_swapcache pages to store the nfs_page.  Thus augment
the new nfs_page_find_request logic.

Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: default avatarMel Gorman <mgorman@suse.de>
Acked-by: default avatarRik van Riel <riel@redhat.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: David S. Miller <davem@davemloft.net>
Cc: Eric B Munson <emunson@mgebm.net>
Cc: Eric Paris <eparis@redhat.com>
Cc: James Morris <jmorris@namei.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Mike Christie <michaelc@cs.wisc.edu>
Cc: Neil Brown <neilb@suse.de>
Cc: Sebastian Andrzej Siewior <sebastian@breakpoint.cc>
Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: Xiaotian Feng <dfeng@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent d56b4ddf

fs/nfs/inode.c

+4 −0
Original line number Diff line number Diff line
@@ -882,6 +882,10 @@ int nfs_revalidate_mapping(struct inode *inode, struct address_space *mapping) 
	struct nfs_inode *nfsi = NFS_I(inode);

	int ret = 0;



	/* swapfiles are not supposed to be shared. */

	if (IS_SWAPFILE(inode))

		goto out;



	if (nfs_mapping_need_revalidate_inode(inode)) {

		ret = __nfs_revalidate_inode(NFS_SERVER(inode), inode);

		if (ret < 0)

fs/nfs/write.c

+35 −14
Original line number Diff line number Diff line
@@ -139,15 +139,28 @@ static void nfs_context_set_write_error(struct nfs_open_context *ctx, int error) 
	set_bit(NFS_CONTEXT_ERROR_WRITE, &ctx->flags);

}



static struct nfs_page *nfs_page_find_request_locked(struct page *page)

static struct nfs_page *

nfs_page_find_request_locked(struct nfs_inode *nfsi, struct page *page)

{

	struct nfs_page *req = NULL;



	if (PagePrivate(page)) {

	if (PagePrivate(page))

		req = (struct nfs_page *)page_private(page);

		if (req != NULL)

			kref_get(&req->wb_kref);

	else if (unlikely(PageSwapCache(page))) {

		struct nfs_page *freq, *t;



		/* Linearly search the commit list for the correct req */

		list_for_each_entry_safe(freq, t, &nfsi->commit_info.list, wb_list) {

			if (freq->wb_page == page) {

				req = freq;

				break;

			}

		}

	}



	if (req)

		kref_get(&req->wb_kref);



	return req;

}
@@ -157,7 +170,7 @@ static struct nfs_page *nfs_page_find_request(struct page *page) 
	struct nfs_page *req = NULL;



	spin_lock(&inode->i_lock);

	req = nfs_page_find_request_locked(page);

	req = nfs_page_find_request_locked(NFS_I(inode), page);

	spin_unlock(&inode->i_lock);

	return req;

}
@@ -258,7 +271,7 @@ static struct nfs_page *nfs_find_and_lock_request(struct page *page, bool nonblo 


	spin_lock(&inode->i_lock);

	for (;;) {

		req = nfs_page_find_request_locked(page);

		req = nfs_page_find_request_locked(NFS_I(inode), page);

		if (req == NULL)

			break;

		if (nfs_lock_request(req))
@@ -413,9 +426,15 @@ static void nfs_inode_add_request(struct inode *inode, struct nfs_page *req) 
	spin_lock(&inode->i_lock);

	if (!nfsi->npages && NFS_PROTO(inode)->have_delegation(inode, FMODE_WRITE))

		inode->i_version++;

	/*

	 * Swap-space should not get truncated. Hence no need to plug the race

	 * with invalidate/truncate.

	 */

	if (likely(!PageSwapCache(req->wb_page))) {

		set_bit(PG_MAPPED, &req->wb_flags);

		SetPagePrivate(req->wb_page);

		set_page_private(req->wb_page, (unsigned long)req);

	}

	nfsi->npages++;

	kref_get(&req->wb_kref);

	spin_unlock(&inode->i_lock);
@@ -432,9 +451,11 @@ static void nfs_inode_remove_request(struct nfs_page *req) 
	BUG_ON (!NFS_WBACK_BUSY(req));



	spin_lock(&inode->i_lock);

	if (likely(!PageSwapCache(req->wb_page))) {

		set_page_private(req->wb_page, 0);

		ClearPagePrivate(req->wb_page);

		clear_bit(PG_MAPPED, &req->wb_flags);

	}

	nfsi->npages--;

	spin_unlock(&inode->i_lock);

	nfs_release_request(req);
@@ -730,7 +751,7 @@ static struct nfs_page *nfs_try_to_update_request(struct inode *inode, 
	spin_lock(&inode->i_lock);



	for (;;) {

		req = nfs_page_find_request_locked(page);

		req = nfs_page_find_request_locked(NFS_I(inode), page);

		if (req == NULL)

			goto out_unlock;
@@ -1744,7 +1765,7 @@ int nfs_wb_page_cancel(struct inode *inode, struct page *page) 
 */

int nfs_wb_page(struct inode *inode, struct page *page)

{

	loff_t range_start = page_offset(page);

	loff_t range_start = page_file_offset(page);

	loff_t range_end = range_start + (loff_t)(PAGE_CACHE_SIZE - 1);

	struct writeback_control wbc = {

		.sync_mode = WB_SYNC_ALL,

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