[PATCH 3/3] xfs_io: add fpunch command for hole punching via fallocate

[Christoph Hellwig <hch@xxxxxxxxxxxxx>]

Add a fpunch command which simply uses fallocate to punch a hole for the
given offset and length.

Signed-off-by: Josef Bacik <josef@xxxxxxxxxx>
Signed-off-by: Christoph Hellwig <hch@xxxxxx>

---
 io/prealloc.c |   45 +++++++++++++++++++++++++++++++++++++++++----
 1 files changed, 41 insertions(+), 4 deletions(-)

Index: xfsprogs-dev/io/prealloc.c
===================================================================
--- xfsprogs-dev.orig/io/prealloc.c     2011-03-05 00:07:16.000000000 +0000
+++ xfsprogs-dev/io/prealloc.c  2011-03-05 00:10:37.000000000 +0000
@@ -36,6 +36,7 @@ static cmdinfo_t unresvsp_cmd;
 static cmdinfo_t zero_cmd;
 #if defined(HAVE_FALLOCATE)
 static cmdinfo_t falloc_cmd;
+static cmdinfo_t fpunch_cmd;
 #endif
 
 static int
@@ -183,7 +184,26 @@ fallocate_f(
        }
        return 0;
 }
-#endif
+
+static int
+fpunch_f(
+        int            argc,
+        char           **argv)
+{
+       xfs_flock64_t   segment;
+       int             mode = FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE;
+
+       if (!offset_length(argv[1], argv[2], &segment))
+               return 0;
+
+       if (fallocate(file->fd, mode,
+                       segment.l_start, segment.l_len)) {
+               perror("fallocate");
+               return 0;
+       }
+       return 0;
+}
+#endif /* HAVE_FALLOCATE */
 
 void
 prealloc_init(void)
@@ -246,7 +266,16 @@ prealloc_init(void)
        falloc_cmd.args = _("[-k] [-p] off len");
        falloc_cmd.oneline =
                _("allocates space associated with part of a file via 
fallocate");
-
        add_command(&falloc_cmd);
-#endif
+
+       fpunch_cmd.name = _("fpunch");
+       fpunch_cmd.cfunc = fpunch_f;
+       fpunch_cmd.argmin = 2;
+       fpunch_cmd.argmax = 2;
+       fpunch_cmd.flags = CMD_NOMAP_OK | CMD_FOREIGN_OK;
+       fpunch_cmd.args = _("off len");
+       fpunch_cmd.oneline =
+               _("de-allocates space assocated with part of a file via 
fallocate");
+       add_command(&fpunch_cmd);
+#endif /* HAVE_FALLOCATE */
 }