From: Trond Myklebust Date: Tue, 17 Apr 2007 17:15:43 -0400 NFS: Fix race in nfs_set_page_dirty Protect nfs_set_page_dirty() against races with nfs_inode_add_request. Signed-off-by: Trond Myklebust --- fs/nfs/write.c | 17 ++++++++++++++--- 1 files changed, 14 insertions(+), 3 deletions(-) diff --git a/fs/nfs/write.c b/fs/nfs/write.c index ce5b4a9..7975589 100644 --- a/fs/nfs/write.c +++ b/fs/nfs/write.c @@ -388,6 +388,8 @@ static int nfs_inode_add_request(struct inode *inode, struct nfs_page *req) } SetPagePrivate(req->wb_page); set_page_private(req->wb_page, (unsigned long)req); + if (PageDirty(req->wb_page)) + set_bit(PG_NEED_FLUSH, &req->wb_flags); nfsi->npages++; atomic_inc(&req->wb_count); return 0; @@ -407,6 +409,8 @@ static void nfs_inode_remove_request(struct nfs_page *req) set_page_private(req->wb_page, 0); ClearPagePrivate(req->wb_page); radix_tree_delete(&nfsi->nfs_page_tree, req->wb_index); + if (test_and_clear_bit(PG_NEED_FLUSH, &req->wb_flags)) + __set_page_dirty_nobuffers(req->wb_page); nfsi->npages--; if (!nfsi->npages) { spin_unlock(&nfsi->req_lock); @@ -1527,15 +1531,22 @@ int nfs_wb_page(struct inode *inode, struct page* page) int nfs_set_page_dirty(struct page *page) { + spinlock_t *req_lock = &NFS_I(page->mapping->host)->req_lock; struct nfs_page *req; + int ret; - req = nfs_page_find_request(page); + spin_lock(req_lock); + req = nfs_page_find_request_locked(page); if (req != NULL) { /* Mark any existing write requests for flushing */ - set_bit(PG_NEED_FLUSH, &req->wb_flags); + ret = !test_and_set_bit(PG_NEED_FLUSH, &req->wb_flags); + spin_unlock(req_lock); nfs_release_request(req); + return ret; } - return __set_page_dirty_nobuffers(page); + ret = __set_page_dirty_nobuffers(page); + spin_unlock(req_lock); + return ret; }