From ddeff520f02b92128132c282c350fa72afffb84a Mon Sep 17 00:00:00 2001 From: Nikita Danilov Date: Wed, 9 Aug 2006 13:53:47 -0400 Subject: [PATCH] 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 (cherry picked from 374d969debfb290bafcb41d28918dc6f7e43ce31 commit) --- fs/nfs/file.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/fs/nfs/file.c b/fs/nfs/file.c index cc2b874ad5a4..48e892880d5b 100644 --- a/fs/nfs/file.c +++ b/fs/nfs/file.c @@ -312,7 +312,13 @@ static void nfs_invalidate_page(struct page *page, unsigned long offset) 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 = { -- GitLab