Commit 5a6d41b3 authored by Trond Myklebust's avatar Trond Myklebust Committed by Linus Torvalds
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NFS: Ensure PG_writeback is cleared when writeback fails 



If the writebacks are cancelled via nfs_cancel_dirty_list, or due to the
memory allocation failing in nfs_flush_one/nfs_flush_multi, then we must
ensure that the PG_writeback flag is cleared.

Also ensure that we actually own the PG_writeback flag whenever we
schedule a new writeback by making nfs_set_page_writeback() return the
value of test_set_page_writeback().
The PG_writeback page flag ends up replacing the functionality of the
PG_FLUSHING nfs_page flag, so we rip that out too.

Signed-off-by: default avatarTrond Myklebust <Trond.Myklebust@netapp.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 60fa3f76

fs/nfs/write.c

+15 −7
Original line number Diff line number Diff line
@@ -218,9 +218,11 @@ int nfs_congestion_kb; 
#define NFS_CONGESTION_OFF_THRESH	\

	(NFS_CONGESTION_ON_THRESH - (NFS_CONGESTION_ON_THRESH >> 2))



static void nfs_set_page_writeback(struct page *page)

static int nfs_set_page_writeback(struct page *page)

{

	if (!test_set_page_writeback(page)) {

	int ret = test_set_page_writeback(page);



	if (!ret) {

		struct inode *inode = page->mapping->host;

		struct nfs_server *nfss = NFS_SERVER(inode);
@@ -228,6 +230,7 @@ static void nfs_set_page_writeback(struct page *page) 
				NFS_CONGESTION_ON_THRESH)

			set_bdi_congested(&nfss->backing_dev_info, WRITE);

	}

	return ret;

}



static void nfs_end_page_writeback(struct page *page)
@@ -277,10 +280,8 @@ static int nfs_page_mark_flush(struct page *page) 
		spin_lock(req_lock);

	}

	spin_unlock(req_lock);

	if (test_and_set_bit(PG_FLUSHING, &req->wb_flags) == 0) {

	if (nfs_set_page_writeback(page) == 0)

		nfs_mark_request_dirty(req);

		nfs_set_page_writeback(page);

	}

	ret = test_bit(PG_NEED_FLUSH, &req->wb_flags);

	nfs_unlock_request(req);

	return ret;
@@ -424,7 +425,6 @@ nfs_mark_request_dirty(struct nfs_page *req) 
static void

nfs_redirty_request(struct nfs_page *req)

{

	clear_bit(PG_FLUSHING, &req->wb_flags);

	__set_page_dirty_nobuffers(req->wb_page);

}
@@ -434,7 +434,11 @@ nfs_redirty_request(struct nfs_page *req) 
static inline int

nfs_dirty_request(struct nfs_page *req)

{

	return test_bit(PG_FLUSHING, &req->wb_flags) == 0;

	struct page *page = req->wb_page;



	if (page == NULL)

		return 0;

	return !PageWriteback(req->wb_page);

}



#if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4)
@@ -500,6 +504,7 @@ static void nfs_cancel_dirty_list(struct list_head *head) 
	while(!list_empty(head)) {

		req = nfs_list_entry(head->next);

		nfs_list_remove_request(req);

		nfs_end_page_writeback(req->wb_page);

		nfs_inode_remove_request(req);

		nfs_clear_page_writeback(req);

	}
@@ -890,6 +895,7 @@ out_bad: 
		list_del(&data->pages);

		nfs_writedata_release(data);

	}

	nfs_end_page_writeback(req->wb_page);

	nfs_redirty_request(req);

	nfs_clear_page_writeback(req);

	return -ENOMEM;
@@ -935,6 +941,7 @@ static int nfs_flush_one(struct inode *inode, struct list_head *head, int how) 
	while (!list_empty(head)) {

		struct nfs_page *req = nfs_list_entry(head->next);

		nfs_list_remove_request(req);

		nfs_end_page_writeback(req->wb_page);

		nfs_redirty_request(req);

		nfs_clear_page_writeback(req);

	}
@@ -970,6 +977,7 @@ out_err: 
	while (!list_empty(head)) {

		req = nfs_list_entry(head->next);

		nfs_list_remove_request(req);

		nfs_end_page_writeback(req->wb_page);

		nfs_redirty_request(req);

		nfs_clear_page_writeback(req);

	}

include/linux/nfs_page.h

+0 −1
Original line number Diff line number Diff line
@@ -31,7 +31,6 @@ 
#define PG_NEED_COMMIT		1

#define PG_NEED_RESCHED		2

#define PG_NEED_FLUSH		3

#define PG_FLUSHING		4



struct nfs_inode;

struct nfs_page {

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