From 5af7926ff33b68b3ba46531471c6e0564b285efc Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Tue, 5 May 2009 15:41:25 +0200 Subject: enforce ->sync_fs is only called for rw superblock Make sure a superblock really is writeable by checking MS_RDONLY under s_umount. sync_filesystems needed some re-arragement for that, but all but one sync_filesystem caller had the correct locking already so that we could add that check there. cachefiles grew s_umount locking. I've also added a WARN_ON to sync_filesystem to assert this for future callers. Signed-off-by: Christoph Hellwig Signed-off-by: Al Viro --- fs/cachefiles/interface.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'fs/cachefiles') diff --git a/fs/cachefiles/interface.c b/fs/cachefiles/interface.c index dafd484d7bda..431accd475a7 100644 --- a/fs/cachefiles/interface.c +++ b/fs/cachefiles/interface.c @@ -354,7 +354,9 @@ static void cachefiles_sync_cache(struct fscache_cache *_cache) /* make sure all pages pinned by operations on behalf of the netfs are * written to disc */ cachefiles_begin_secure(cache, &saved_cred); + down_read(&cache->mnt->mnt_sb->s_umount); ret = sync_filesystem(cache->mnt->mnt_sb); + up_read(&cache->mnt->mnt_sb->s_umount); cachefiles_end_secure(cache, saved_cred); if (ret == -EIO) -- cgit v1.2.3-59-g8ed1b