[XFS] convert xfs_getbmap to take formatter functions

Preliminary work to hook up fiemap, this allows us to pass in an
arbitrary formatter to copy extent data back to userspace.

The formatter takes info for 1 extent, a pointer to the user "thing*"
and a pointer to a "filled" variable to indicate whether a userspace
buffer did get filled in (for fiemap, hole "extents" are skipped).

I'm just using the getbmapx struct as a "common denominator" because
as far as I can see, it holds all info that any formatters will care
about.

("*thing" because fiemap doesn't pass the user pointer around, but rather
has a pointer to a fiemap info structure, and helpers associated with it)

Signed-off-by: Eric Sandeen <sandeen@sandeen.net>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Niv Sardi <xaiki@sgi.com>

1 files changed, 39 insertions, 25 deletions

diff --git a/fs/xfs/linux-2.6/xfs_ioctl.c b/fs/xfs/linux-2.6/xfs_ioctl.c
index f1bd6c36e6fe..d59705999534 100644
--- a/fs/xfs/linux-2.6/xfs_ioctl.c
+++ b/fs/xfs/linux-2.6/xfs_ioctl.c
@@ -1250,43 +1250,67 @@ xfs_ioc_setxflags(
 }
 
 STATIC int
+xfs_getbmap_format(void **ap, struct getbmapx *bmv, int *full)
+{
+        struct getbmap __user   *base = *ap;
+
+        /* copy only getbmap portion (not getbmapx) */
+        if (copy_to_user(base, bmv, sizeof(struct getbmap)))
+                return XFS_ERROR(EFAULT);
+
+        *ap += sizeof(struct getbmap);
+        return 0;
+}
+
+STATIC int
 xfs_ioc_getbmap(
         struct xfs_inode        *ip,
         int                     ioflags,
         unsigned int            cmd,
         void                    __user *arg)
 {
-        struct getbmap          bm;
-        int                     iflags;
+        struct getbmapx         bmx;
         int                     error;
 
-        if (copy_from_user(&bm, arg, sizeof(bm)))
+        if (copy_from_user(&bmx, arg, sizeof(struct getbmapx)))
                 return -XFS_ERROR(EFAULT);
 
-        if (bm.bmv_count < 2)
+        if (bmx.bmv_count < 2)
                 return -XFS_ERROR(EINVAL);
 
-        iflags = (cmd == XFS_IOC_GETBMAPA ? BMV_IF_ATTRFORK : 0);
+        bmx.bmv_iflags = (cmd == XFS_IOC_GETBMAPA ? BMV_IF_ATTRFORK : 0);
         if (ioflags & IO_INVIS)
-                iflags |= BMV_IF_NO_DMAPI_READ;
+                bmx.bmv_iflags |= BMV_IF_NO_DMAPI_READ;
 
-        error = xfs_getbmap(ip, &bm, (struct getbmap __user *)arg+1, iflags);
+        error = xfs_getbmap(ip, &bmx, xfs_getbmap_format,
+                            (struct getbmap *)arg+1);
         if (error)
                 return -error;
 
-        if (copy_to_user(arg, &bm, sizeof(bm)))
+        /* copy back header - only size of getbmap */
+        if (copy_to_user(arg, &bmx, sizeof(struct getbmap)))
                 return -XFS_ERROR(EFAULT);
         return 0;
 }
 
 STATIC int
+xfs_getbmapx_format(void **ap, struct getbmapx *bmv, int *full)
+{
+        struct getbmapx __user  *base = *ap;
+
+        if (copy_to_user(base, bmv, sizeof(struct getbmapx)))
+                return XFS_ERROR(EFAULT);
+
+        *ap += sizeof(struct getbmapx);
+        return 0;
+}
+
+STATIC int
 xfs_ioc_getbmapx(
         struct xfs_inode        *ip,
         void                    __user *arg)
 {
         struct getbmapx         bmx;
-        struct getbmap          bm;
-        int                     iflags;
         int                     error;
 
         if (copy_from_user(&bmx, arg, sizeof(bmx)))
@@ -1295,26 +1319,16 @@ xfs_ioc_getbmapx(
         if (bmx.bmv_count < 2)
                 return -XFS_ERROR(EINVAL);
 
-        /*
-         * Map input getbmapx structure to a getbmap
-         * structure for xfs_getbmap.
-         */
-        GETBMAP_CONVERT(bmx, bm);
-
-        iflags = bmx.bmv_iflags;
-
-        if (iflags & (~BMV_IF_VALID))
+        if (bmx.bmv_iflags & (~BMV_IF_VALID))
                 return -XFS_ERROR(EINVAL);
 
-        iflags |= BMV_IF_EXTENDED;
-
-        error = xfs_getbmap(ip, &bm, (struct getbmapx __user *)arg+1, iflags);
+        error = xfs_getbmap(ip, &bmx, xfs_getbmapx_format,
+                            (struct getbmapx *)arg+1);
         if (error)
                 return -error;
 
-        GETBMAP_CONVERT(bm, bmx);
-
-        if (copy_to_user(arg, &bmx, sizeof(bmx)))
+        /* copy back header */
+        if (copy_to_user(arg, &bmx, sizeof(struct getbmapx)))
                 return -XFS_ERROR(EFAULT);
 
         return 0;