From 71be6b4942dd64bc17728f82f787be98fd8afed7 Mon Sep 17 00:00:00 2001 From: "Darrick J. Wong" Date: Mon, 3 Oct 2016 09:11:14 -0700 Subject: vfs: add a FALLOC_FL_UNSHARE mode to fallocate to unshare a range of blocks Add a new fallocate mode flag that explicitly unshares blocks on filesystems that support such features. The new flag can only be used with an allocate-mode fallocate call. Signed-off-by: Darrick J. Wong --- fs/open.c | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'fs/open.c') diff --git a/fs/open.c b/fs/open.c index 4fd6e256f4f45..d58525dda28dd 100644 --- a/fs/open.c +++ b/fs/open.c @@ -256,6 +256,11 @@ int vfs_fallocate(struct file *file, int mode, loff_t offset, loff_t len) (mode & ~FALLOC_FL_INSERT_RANGE)) return -EINVAL; + /* Unshare range should only be used with allocate mode. */ + if ((mode & FALLOC_FL_UNSHARE_RANGE) && + (mode & ~(FALLOC_FL_UNSHARE_RANGE | FALLOC_FL_KEEP_SIZE))) + return -EINVAL; + if (!(file->f_mode & FMODE_WRITE)) return -EBADF; -- cgit v1.2.3