Commit 612c9384 authored by Trond Myklebust's avatar Trond Myklebust Committed by Linus Torvalds
Browse files

NFS: Fix the 'desynchronized value of nfs_i.ncommit' error 



Redirtying a request that is already marked for commit will screw up the
accounting for NR_UNSTABLE_NFS as well as nfs_i.ncommit.
Ensure that all requests on the commit queue are labelled with the
PG_NEED_COMMIT flag, and avoid moving them onto the dirty list inside
nfs_page_mark_flush().

Also inline nfs_mark_request_dirty() into nfs_page_mark_flush() for
atomicity reasons. Avoid dropping the spinlock until we're done marking the
request in the radix tree and have added it to the ->dirty list.

Signed-off-by: default avatarTrond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 6d677e35

fs/nfs/write.c

+22 −25
Original line number Diff line number Diff line
@@ -38,7 +38,6 @@ 
static struct nfs_page * nfs_update_request(struct nfs_open_context*,

					    struct page *,

					    unsigned int, unsigned int);

static void nfs_mark_request_dirty(struct nfs_page *req);

static long nfs_flush_mapping(struct address_space *mapping, struct writeback_control *wbc, int how);

static const struct rpc_call_ops nfs_write_partial_ops;

static const struct rpc_call_ops nfs_write_full_ops;
@@ -255,7 +254,8 @@ static void nfs_end_page_writeback(struct page *page) 
static int nfs_page_mark_flush(struct page *page)

{

	struct nfs_page *req;

	spinlock_t *req_lock = &NFS_I(page->mapping->host)->req_lock;

	struct nfs_inode *nfsi = NFS_I(page->mapping->host);

	spinlock_t *req_lock = &nfsi->req_lock;

	int ret;



	spin_lock(req_lock);
@@ -279,11 +279,23 @@ static int nfs_page_mark_flush(struct page *page) 
			return ret;

		spin_lock(req_lock);

	}

	if (test_bit(PG_NEED_COMMIT, &req->wb_flags)) {

		/* This request is marked for commit */

		spin_unlock(req_lock);

		nfs_unlock_request(req);

		return 1;

	}

	if (nfs_set_page_writeback(page) == 0) {

		nfs_list_remove_request(req);

		nfs_mark_request_dirty(req);

	}

		/* add the request to the inode's dirty list. */

		radix_tree_tag_set(&nfsi->nfs_page_tree,

				req->wb_index, NFS_PAGE_TAG_DIRTY);

		nfs_list_add_request(req, &nfsi->dirty);

		nfsi->ndirty++;

		spin_unlock(req_lock);

		__mark_inode_dirty(page->mapping->host, I_DIRTY_PAGES);

	} else

		spin_unlock(req_lock);

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

	nfs_unlock_request(req);

	return ret;
@@ -406,24 +418,6 @@ static void nfs_inode_remove_request(struct nfs_page *req) 
	nfs_release_request(req);

}



/*

 * Add a request to the inode's dirty list.

 */

static void

nfs_mark_request_dirty(struct nfs_page *req)

{

	struct inode *inode = req->wb_context->dentry->d_inode;

	struct nfs_inode *nfsi = NFS_I(inode);



	spin_lock(&nfsi->req_lock);

	radix_tree_tag_set(&nfsi->nfs_page_tree,

			req->wb_index, NFS_PAGE_TAG_DIRTY);

	nfs_list_add_request(req, &nfsi->dirty);

	nfsi->ndirty++;

	spin_unlock(&nfsi->req_lock);

	__mark_inode_dirty(inode, I_DIRTY_PAGES);

}



static void

nfs_redirty_request(struct nfs_page *req)

{
@@ -438,7 +432,7 @@ nfs_dirty_request(struct nfs_page *req) 
{

	struct page *page = req->wb_page;



	if (page == NULL)

	if (page == NULL || test_bit(PG_NEED_COMMIT, &req->wb_flags))

		return 0;

	return !PageWriteback(req->wb_page);

}
@@ -456,6 +450,7 @@ nfs_mark_request_commit(struct nfs_page *req) 
	spin_lock(&nfsi->req_lock);

	nfs_list_add_request(req, &nfsi->commit);

	nfsi->ncommit++;

	set_bit(PG_NEED_COMMIT, &(req)->wb_flags);

	spin_unlock(&nfsi->req_lock);

	inc_zone_page_state(req->wb_page, NR_UNSTABLE_NFS);

	__mark_inode_dirty(inode, I_DIRTY_DATASYNC);
@@ -470,7 +465,7 @@ int nfs_write_need_commit(struct nfs_write_data *data) 
static inline

int nfs_reschedule_unstable_write(struct nfs_page *req)

{

	if (test_and_clear_bit(PG_NEED_COMMIT, &req->wb_flags)) {

	if (test_bit(PG_NEED_COMMIT, &req->wb_flags)) {

		nfs_mark_request_commit(req);

		return 1;

	}
@@ -557,6 +552,7 @@ static void nfs_cancel_commit_list(struct list_head *head) 
		req = nfs_list_entry(head->next);

		dec_zone_page_state(req->wb_page, NR_UNSTABLE_NFS);

		nfs_list_remove_request(req);

		clear_bit(PG_NEED_COMMIT, &(req)->wb_flags);

		nfs_inode_remove_request(req);

		nfs_unlock_request(req);

	}
@@ -1295,6 +1291,7 @@ static void nfs_commit_done(struct rpc_task *task, void *calldata) 
	while (!list_empty(&data->pages)) {

		req = nfs_list_entry(data->pages.next);

		nfs_list_remove_request(req);

		clear_bit(PG_NEED_COMMIT, &(req)->wb_flags);

		dec_zone_page_state(req->wb_page, NR_UNSTABLE_NFS);



		dprintk("NFS: commit (%s/%Ld %d@%Ld)",

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