[PATCH 08/14] xfs: teach fiemap about reflink'd extents

["Darrick J. Wong" <darrick.wong@xxxxxxxxxx>]

Teach FIEMAP to report shared (i.e. reflinked) extents.

Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
---
 fs/xfs/xfs_bmap_util.c |    2 +-
 fs/xfs/xfs_bmap_util.h |    3 ++
 fs/xfs/xfs_ioctl.c     |    4 ++-
 fs/xfs/xfs_iops.c      |   62 +++++++++++++++++++++++++++++++++++++++---------
 4 files changed, 55 insertions(+), 16 deletions(-)


diff --git a/fs/xfs/xfs_bmap_util.c b/fs/xfs/xfs_bmap_util.c
index 17975fe..090cf75 100644
--- a/fs/xfs/xfs_bmap_util.c
+++ b/fs/xfs/xfs_bmap_util.c
@@ -689,7 +689,7 @@ xfs_getbmap(
                int full = 0;   /* user array is full */
 
                /* format results & advance arg */
-               error = formatter(&arg, &out[i], &full);
+               error = formatter(ip, &arg, &out[i], &full);
                if (error || full)
                        break;
        }
diff --git a/fs/xfs/xfs_bmap_util.h b/fs/xfs/xfs_bmap_util.h
index af97d9a..9919b9a 100644
--- a/fs/xfs/xfs_bmap_util.h
+++ b/fs/xfs/xfs_bmap_util.h
@@ -37,7 +37,8 @@ int   xfs_bmap_punch_delalloc_range(struct xfs_inode *ip,
                xfs_fileoff_t start_fsb, xfs_fileoff_t length);
 
 /* bmap to userspace formatter - copy to user & advance pointer */
-typedef int (*xfs_bmap_format_t)(void **, struct getbmapx *, int *);
+typedef int (*xfs_bmap_format_t)(xfs_inode_t *ip, void **, struct getbmapx *,
+               int *);
 int    xfs_getbmap(struct xfs_inode *ip, struct getbmapx *bmv,
                xfs_bmap_format_t formatter, void *arg);
 
diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
index efc6e8d..c590786 100644
--- a/fs/xfs/xfs_ioctl.c
+++ b/fs/xfs/xfs_ioctl.c
@@ -1352,7 +1352,7 @@ out_drop_write:
 }
 
 STATIC int
-xfs_getbmap_format(void **ap, struct getbmapx *bmv, int *full)
+xfs_getbmap_format(xfs_inode_t *ip, void **ap, struct getbmapx *bmv, int *full)
 {
        struct getbmap __user   *base = (struct getbmap __user *)*ap;
 
@@ -1396,7 +1396,7 @@ xfs_ioc_getbmap(
 }
 
 STATIC int
-xfs_getbmapx_format(void **ap, struct getbmapx *bmv, int *full)
+xfs_getbmapx_format(xfs_inode_t *ip, void **ap, struct getbmapx *bmv, int 
*full)
 {
        struct getbmapx __user  *base = (struct getbmapx __user *)*ap;
 
diff --git a/fs/xfs/xfs_iops.c b/fs/xfs/xfs_iops.c
index 2923419..0336fed 100644
--- a/fs/xfs/xfs_iops.c
+++ b/fs/xfs/xfs_iops.c
@@ -38,6 +38,8 @@
 #include "xfs_dir2.h"
 #include "xfs_trans_space.h"
 #include "xfs_pnfs.h"
+#include "xfs_bit.h"
+#include "xfs_reflink.h"
 
 #include <linux/capability.h>
 #include <linux/xattr.h>
@@ -1017,14 +1019,21 @@ xfs_vn_update_time(
  */
 STATIC int
 xfs_fiemap_format(
+       xfs_inode_t             *ip,
        void                    **arg,
        struct getbmapx         *bmv,
        int                     *full)
 {
-       int                     error;
+       int                     error = 0;
        struct fiemap_extent_info *fieinfo = *arg;
        u32                     fiemap_flags = 0;
-       u64                     logical, physical, length;
+       u64                     logical, physical, length, loop_len, len;
+       xfs_extlen_t            elen;
+       xfs_nlink_t             nr;
+       xfs_fsblock_t           fsbno;
+       xfs_agnumber_t          agno;
+       xfs_agblock_t           agbno;
+       xfs_mount_t             *mp = ip->i_mount;
 
        /* Do nothing for a hole */
        if (bmv->bmv_block == -1LL)
@@ -1032,7 +1041,7 @@ xfs_fiemap_format(
 
        logical = BBTOB(bmv->bmv_offset);
        physical = BBTOB(bmv->bmv_block);
-       length = BBTOB(bmv->bmv_length);
+       length = loop_len = BBTOB(bmv->bmv_length);
 
        if (bmv->bmv_oflags & BMV_OF_PREALLOC)
                fiemap_flags |= FIEMAP_EXTENT_UNWRITTEN;
@@ -1041,16 +1050,45 @@ xfs_fiemap_format(
                                 FIEMAP_EXTENT_UNKNOWN);
                physical = 0;   /* no block yet */
        }
-       if (bmv->bmv_oflags & BMV_OF_LAST)
-               fiemap_flags |= FIEMAP_EXTENT_LAST;
-
-       error = fiemap_fill_next_extent(fieinfo, logical, physical,
-                                       length, fiemap_flags);
-       if (error > 0) {
-               error = 0;
-               *full = 1;      /* user array now full */
-       }
 
+       while (loop_len > 0) {
+               u32 ext_flags = 0;
+
+               if (bmv->bmv_oflags & BMV_OF_DELALLOC) {
+                       physical = 0;
+                       len = loop_len;
+                       nr = 1;
+               } else if (xfs_sb_version_hasreflink(&mp->m_sb)) {
+                       fsbno = XFS_DADDR_TO_FSB(mp, BTOBB(physical));
+                       agno = XFS_FSB_TO_AGNO(mp, fsbno);
+                       agbno = XFS_FSB_TO_AGBNO(mp, fsbno);
+                       error = xfs_reflink_get_refcount(mp, agno, agbno,
+                                       &elen, &nr);
+                       if (error)
+                               goto out;
+                       len = XFS_FSB_TO_B(mp, elen);
+                       if (len == 0 || len > loop_len)
+                               len = loop_len;
+                       if (nr >= 2)
+                               ext_flags |= FIEMAP_EXTENT_SHARED;
+               } else
+                       len = loop_len;
+               if ((bmv->bmv_oflags & BMV_OF_LAST) &&
+                   len == loop_len)
+                       ext_flags |= FIEMAP_EXTENT_LAST;
+
+               error = fiemap_fill_next_extent(fieinfo, logical, physical,
+                                               len, fiemap_flags | ext_flags);
+               if (error > 0) {
+                       error = 0;
+                       *full = 1;      /* user array now full */
+                       goto out;
+               }
+               logical += len;
+               physical += len;
+               loop_len -= len;
+       }
+out:
        return error;
 }