Add ->flock() operation to low and high level interfaces

This fixes problems with emulating flock() with POSIX locking.
Reported by Sebastian Pipping.

As with lock/setlk/getlk most filesystems don't need to implement
this, as the kernel takes care of file locking.  The only reason to
implement locking operations is for network filesystems which want
file locking to work between clients.

1 files changed, 44 insertions, 0 deletions

diff --git a/lib/fuse.c b/lib/fuse.c
index 50f3d0d..f7740c3 100644
--- a/lib/fuse.c
+++ b/lib/fuse.c
@@ -1933,6 +1933,27 @@ int fuse_fs_lock(struct fuse_fs *fs, const char *path,
 	}
 }
 
+int fuse_fs_flock(struct fuse_fs *fs, const char *path,
+		  struct fuse_file_info *fi, int op)
+{
+	fuse_get_context()->private_data = fs->user_data;
+	if (fs->op.flock) {
+		if (fs->debug) {
+			int xop = op & ~LOCK_NB;
+
+			fprintf(stderr, "lock[%llu] %s%s\n",
+				(unsigned long long) fi->fh,
+				xop == LOCK_SH ? "LOCK_SH" :
+				(xop == LOCK_EX ? "LOCK_EX" :
+				 (xop == LOCK_UN ? "LOCK_UN" : "???")),
+				(op & LOCK_NB) ? "|LOCK_NB" : "");
+		}
+		return fs->op.flock(path, fi, op);
+	} else {
+		return -ENOSYS;
+	}
+}
+
 int fuse_fs_chown(struct fuse_fs *fs, const char *path, uid_t uid, gid_t gid)
 {
 	fuse_get_context()->private_data = fs->user_data;
@@ -2410,6 +2431,10 @@ void fuse_fs_init(struct fuse_fs *fs, struct fuse_conn_info *conn)
 	fuse_get_context()->private_data = fs->user_data;
 	if (!fs->op.write_buf)
 		conn->want &= ~FUSE_CAP_SPLICE_READ;
+	if (!fs->op.lock)
+		conn->want &= ~FUSE_CAP_POSIX_LOCKS;
+	if (!fs->op.flock)
+		conn->want &= ~FUSE_CAP_FLOCK_LOCKS;
 	if (fs->op.init)
 		fs->user_data = fs->op.init(conn);
 }
@@ -3754,6 +3779,24 @@ static void fuse_lib_setlk(fuse_req_t req, fuse_ino_t ino,
 	reply_err(req, err);
 }
 
+static void fuse_lib_flock(fuse_req_t req, fuse_ino_t ino,
+			   struct fuse_file_info *fi, int op)
+{
+	struct fuse *f = req_fuse_prepare(req);
+	char *path;
+	int err;
+
+	err = get_path_nullok(f, ino, &path);
+	if (err == 0) {
+		struct fuse_intr_data d;
+		fuse_prepare_interrupt(f, req, &d);
+		err = fuse_fs_flock(f->fs, path, fi, op);
+		fuse_finish_interrupt(f, req, &d);
+		free_path(f, ino, path);
+	}
+	reply_err(req, err);
+}
+
 static void fuse_lib_bmap(fuse_req_t req, fuse_ino_t ino, size_t blocksize,
 			  uint64_t idx)
 {
@@ -3939,6 +3982,7 @@ static struct fuse_lowlevel_ops fuse_path_ops = {
 	.removexattr = fuse_lib_removexattr,
 	.getlk = fuse_lib_getlk,
 	.setlk = fuse_lib_setlk,
+	.flock = fuse_lib_flock,
 	.bmap = fuse_lib_bmap,
 	.ioctl = fuse_lib_ioctl,
 	.poll = fuse_lib_poll,