ocfs2: Support xfs style space reservation ioctls

We re-use the RESVSP/UNRESVSP ioctls from xfs which allow the user to
allocate and deallocate regions to a file without zeroing data or changing
i_size.

Though renamed, the structure passed in from user is identical to struct
xfs_flock64. The three fields that are actually used right now are l_whence,
l_start and l_len.

This should get ocfs2 immediate compatibility with userspace software using
the pre-existing xfs ioctls.

Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>

1 files changed, 26 insertions, 0 deletions

diff --git a/fs/ocfs2/ocfs2_fs.h b/fs/ocfs2/ocfs2_fs.h
index c20a74b99d87..82f8a75b207e 100644
--- a/fs/ocfs2/ocfs2_fs.h
+++ b/fs/ocfs2/ocfs2_fs.h
@@ -175,6 +175,32 @@
 #define OCFS2_IOC32_SETFLAGS    _IOW('f', 2, int)
 
 /*
+ * Space reservation / allocation / free ioctls and argument structure
+ * are designed to be compatible with XFS.
+ *
+ * ALLOCSP* and FREESP* are not and will never be supported, but are
+ * included here for completeness.
+ */
+struct ocfs2_space_resv {
+        __s16           l_type;
+        __s16           l_whence;
+        __s64           l_start;
+        __s64           l_len;          /* len == 0 means until end of file */
+        __s32           l_sysid;
+        __u32           l_pid;
+        __s32           l_pad[4];       /* reserve area                     */
+};
+
+#define OCFS2_IOC_ALLOCSP               _IOW ('X', 10, struct ocfs2_space_resv)
+#define OCFS2_IOC_FREESP                _IOW ('X', 11, struct ocfs2_space_resv)
+#define OCFS2_IOC_RESVSP                _IOW ('X', 40, struct ocfs2_space_resv)
+#define OCFS2_IOC_UNRESVSP      _IOW ('X', 41, struct ocfs2_space_resv)
+#define OCFS2_IOC_ALLOCSP64     _IOW ('X', 36, struct ocfs2_space_resv)
+#define OCFS2_IOC_FREESP64      _IOW ('X', 37, struct ocfs2_space_resv)
+#define OCFS2_IOC_RESVSP64      _IOW ('X', 42, struct ocfs2_space_resv)
+#define OCFS2_IOC_UNRESVSP64    _IOW ('X', 43, struct ocfs2_space_resv)
+
+/*
  * Journal Flags (ocfs2_dinode.id1.journal1.i_flags)
  */
 #define OCFS2_JOURNAL_DIRTY_FL  (0x00000001)    /* Journal needs recovery */