From: Nikita Danilov NFS: Fix a potential deadlock in nfs_release_page nfs_wb_page() waits on request completion and, as a result, is not safe to be called from nfs_release_page() invoked by VM scanner as part of GFP_NOFS allocation. Fix possible deadlock by analyzing gfp mask and refusing to release page if __GFP_FS is not set. Signed-off-by: Nikita Danilov Signed-off-by: Trond Myklebust --- fs/nfs/file.c | 8 +++++++- 1 files changed, 7 insertions(+), 1 deletions(-) diff --git a/fs/nfs/file.c b/fs/nfs/file.c index cc2b874..48e8928 100644 --- a/fs/nfs/file.c +++ b/fs/nfs/file.c @@ -312,7 +312,13 @@ static void nfs_invalidate_page(struct p static int nfs_release_page(struct page *page, gfp_t gfp) { - return !nfs_wb_page(page->mapping->host, page); + if (gfp & __GFP_FS) + return !nfs_wb_page(page->mapping->host, page); + else + /* + * Avoid deadlock on nfs_wait_on_request(). + */ + return 0; } const struct address_space_operations nfs_file_aops = {