NFS: Fix a race with the new commit code
This patch fixes a race which occurs due to the fact that we release the
PG_writeback flag while still holding the nfs_page locked.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/fs/nfs/write.c b/fs/nfs/write.c
index 7f40ea3..40297c4 100644
--- a/fs/nfs/write.c
+++ b/fs/nfs/write.c
@@ -201,6 +201,7 @@
struct inode *inode = page->mapping->host;
struct nfs_server *nfss = NFS_SERVER(inode);
+ page_cache_get(page);
if (atomic_long_inc_return(&nfss->writeback) >
NFS_CONGESTION_ON_THRESH) {
set_bdi_congested(&nfss->backing_dev_info,
@@ -216,6 +217,7 @@
struct nfs_server *nfss = NFS_SERVER(inode);
end_page_writeback(page);
+ page_cache_release(page);
if (atomic_long_dec_return(&nfss->writeback) < NFS_CONGESTION_OFF_THRESH)
clear_bdi_congested(&nfss->backing_dev_info, BLK_RW_ASYNC);
}
@@ -665,6 +667,7 @@
/* Update file length */
nfs_grow_file(page, offset, count);
nfs_mark_uptodate(page, req->wb_pgbase, req->wb_bytes);
+ nfs_mark_request_dirty(req);
nfs_clear_page_tag_locked(req);
return 0;
}
@@ -749,13 +752,12 @@
static void nfs_writepage_release(struct nfs_page *req)
{
+ struct page *page = req->wb_page;
- if (PageError(req->wb_page) || !nfs_reschedule_unstable_write(req)) {
- nfs_end_page_writeback(req->wb_page);
+ if (PageError(req->wb_page) || !nfs_reschedule_unstable_write(req))
nfs_inode_remove_request(req);
- } else
- nfs_end_page_writeback(req->wb_page);
nfs_clear_page_tag_locked(req);
+ nfs_end_page_writeback(page);
}
static int flush_task_priority(int how)
@@ -847,9 +849,11 @@
*/
static void nfs_redirty_request(struct nfs_page *req)
{
+ struct page *page = req->wb_page;
+
nfs_mark_request_dirty(req);
- nfs_end_page_writeback(req->wb_page);
nfs_clear_page_tag_locked(req);
+ nfs_end_page_writeback(page);
}
/*
@@ -1084,16 +1088,15 @@
if (nfs_write_need_commit(data)) {
memcpy(&req->wb_verf, &data->verf, sizeof(req->wb_verf));
nfs_mark_request_commit(req);
- nfs_end_page_writeback(page);
dprintk(" marked for commit\n");
goto next;
}
dprintk(" OK\n");
remove_request:
- nfs_end_page_writeback(page);
nfs_inode_remove_request(req);
next:
nfs_clear_page_tag_locked(req);
+ nfs_end_page_writeback(page);
}
nfs_writedata_release(calldata);
}