From 42e49608683ab25fbbbf9c40edb944601e543882 Mon Sep 17 00:00:00 2001 From: Wu Fengguang Date: Fri, 5 Mar 2010 13:42:01 -0800 Subject: [PATCH] vfs: take f_lock on modifying f_mode after open time We'll introduce FMODE_RANDOM which will be runtime modified. So protect all runtime modification to f_mode with f_lock to avoid races. Signed-off-by: Wu Fengguang Cc: Al Viro Cc: Christoph Hellwig Cc: Trond Myklebust Cc: Chuck Lever Cc: [2.6.33.x] Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/file_table.c | 2 ++ fs/nfsd/nfs4state.c | 2 ++ 2 files changed, 4 insertions(+) diff --git a/fs/file_table.c b/fs/file_table.c index b98404b54383..32d12b78bac8 100644 --- a/fs/file_table.c +++ b/fs/file_table.c @@ -393,7 +393,9 @@ retry: continue; if (!(f->f_mode & FMODE_WRITE)) continue; + spin_lock(&f->f_lock); f->f_mode &= ~FMODE_WRITE; + spin_unlock(&f->f_lock); if (file_check_writeable(f) != 0) continue; file_release_write(f); diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c index f19ed866c95f..fcafe6087f69 100644 --- a/fs/nfsd/nfs4state.c +++ b/fs/nfsd/nfs4state.c @@ -1998,7 +1998,9 @@ nfs4_file_downgrade(struct file *filp, unsigned int share_access) { if (share_access & NFS4_SHARE_ACCESS_WRITE) { drop_file_write_access(filp); + spin_lock(&filp->f_lock); filp->f_mode = (filp->f_mode | FMODE_READ) & ~FMODE_WRITE; + spin_unlock(&filp->f_lock); } } -- 2.30.2