fuse: allow umask processing in userspace

This patch lets filesystems handle masking the file mode on creation.
This is needed if filesystem is using ACLs.

 - The CREATE, MKDIR and MKNOD requests are extended with a "umask"
   parameter.

 - A new FUSE_DONT_MASK flag is added to the INIT request/reply.  With
   this the filesystem may request that the create mode is not masked.

CC: Jean-Pierre André <jean-pierre.andre@wanadoo.fr>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>

1 files changed, 8 insertions, 1 deletions

diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c
index d8673ccf90b..6cc501bd018 100644
--- a/fs/fuse/inode.c
+++ b/fs/fuse/inode.c
@@ -725,6 +725,8 @@ static void process_init_reply(struct fuse_conn *fc, struct fuse_req *req)
 			}
 			if (arg->flags & FUSE_BIG_WRITES)
 				fc->big_writes = 1;
+			if (arg->flags & FUSE_DONT_MASK)
+				fc->dont_mask = 1;
 		} else {
 			ra_pages = fc->max_read / PAGE_CACHE_SIZE;
 			fc->no_lock = 1;
@@ -748,7 +750,7 @@ static void fuse_send_init(struct fuse_conn *fc, struct fuse_req *req)
 	arg->minor = FUSE_KERNEL_MINOR_VERSION;
 	arg->max_readahead = fc->bdi.ra_pages * PAGE_CACHE_SIZE;
 	arg->flags |= FUSE_ASYNC_READ | FUSE_POSIX_LOCKS | FUSE_ATOMIC_O_TRUNC |
-		FUSE_EXPORT_SUPPORT | FUSE_BIG_WRITES;
+		FUSE_EXPORT_SUPPORT | FUSE_BIG_WRITES | FUSE_DONT_MASK;
 	req->in.h.opcode = FUSE_INIT;
 	req->in.numargs = 1;
 	req->in.args[0].size = sizeof(*arg);
@@ -864,6 +866,11 @@ static int fuse_fill_super(struct super_block *sb, void *data, int silent)
 	if (err)
 		goto err_put_conn;
 
+	/* Handle umasking inside the fuse code */
+	if (sb->s_flags & MS_POSIXACL)
+		fc->dont_mask = 1;
+	sb->s_flags |= MS_POSIXACL;
+
 	fc->release = fuse_free_conn;
 	fc->flags = d.flags;
 	fc->user_id = d.user_id;