ocfs2: POSIX file locks support
This is actually pretty easy since fs/dlm already handles the bulk of the
work. The Ocfs2 userspace cluster stack module already uses fs/dlm as the
underlying lock manager, so I only had to add the right calls.
Cluster-aware POSIX locks ("plocks") can be turned off by the same means at
UNIX locks - mount with 'noflocks', or create a local-only Ocfs2 volume.
Internally, the file system uses two sets of file_operations, depending on
whether cluster aware plocks is required. This turns out to be easier than
implementing local-only versions of ->lock.
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
diff --git a/fs/ocfs2/file.c b/fs/ocfs2/file.c
index ed38796..1015ef1 100644
--- a/fs/ocfs2/file.c
+++ b/fs/ocfs2/file.c
@@ -2237,6 +2237,10 @@
.permission = ocfs2_permission,
};
+/*
+ * Other than ->lock, keep ocfs2_fops and ocfs2_dops in sync with
+ * ocfs2_fops_no_plocks and ocfs2_dops_no_plocks!
+ */
const struct file_operations ocfs2_fops = {
.llseek = generic_file_llseek,
.read = do_sync_read,
@@ -2251,12 +2255,59 @@
#ifdef CONFIG_COMPAT
.compat_ioctl = ocfs2_compat_ioctl,
#endif
+ .lock = ocfs2_lock,
+ .flock = ocfs2_flock,
+ .splice_read = ocfs2_file_splice_read,
+ .splice_write = ocfs2_file_splice_write,
+};
+
+const struct file_operations ocfs2_dops = {
+ .llseek = generic_file_llseek,
+ .read = generic_read_dir,
+ .readdir = ocfs2_readdir,
+ .fsync = ocfs2_sync_file,
+ .release = ocfs2_dir_release,
+ .open = ocfs2_dir_open,
+ .unlocked_ioctl = ocfs2_ioctl,
+#ifdef CONFIG_COMPAT
+ .compat_ioctl = ocfs2_compat_ioctl,
+#endif
+ .lock = ocfs2_lock,
+ .flock = ocfs2_flock,
+};
+
+/*
+ * POSIX-lockless variants of our file_operations.
+ *
+ * These will be used if the underlying cluster stack does not support
+ * posix file locking, if the user passes the "localflocks" mount
+ * option, or if we have a local-only fs.
+ *
+ * ocfs2_flock is in here because all stacks handle UNIX file locks,
+ * so we still want it in the case of no stack support for
+ * plocks. Internally, it will do the right thing when asked to ignore
+ * the cluster.
+ */
+const struct file_operations ocfs2_fops_no_plocks = {
+ .llseek = generic_file_llseek,
+ .read = do_sync_read,
+ .write = do_sync_write,
+ .mmap = ocfs2_mmap,
+ .fsync = ocfs2_sync_file,
+ .release = ocfs2_file_release,
+ .open = ocfs2_file_open,
+ .aio_read = ocfs2_file_aio_read,
+ .aio_write = ocfs2_file_aio_write,
+ .unlocked_ioctl = ocfs2_ioctl,
+#ifdef CONFIG_COMPAT
+ .compat_ioctl = ocfs2_compat_ioctl,
+#endif
.flock = ocfs2_flock,
.splice_read = ocfs2_file_splice_read,
.splice_write = ocfs2_file_splice_write,
};
-const struct file_operations ocfs2_dops = {
+const struct file_operations ocfs2_dops_no_plocks = {
.llseek = generic_file_llseek,
.read = generic_read_dir,
.readdir = ocfs2_readdir,