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PATCH 3/3 v3] hook up fiemap & associated formatter

To: xfs-oss <xfs@xxxxxxxxxxx>
Subject: PATCH 3/3 v3] hook up fiemap & associated formatter
From: Eric Sandeen <sandeen@xxxxxxxxxxx>
Date: Sun, 26 Oct 2008 16:32:12 -0500
In-reply-to: <4904E0DE.3040902@xxxxxxxxxxx>
References: <4904E0DE.3040902@xxxxxxxxxxx>
User-agent: Thunderbird 2.0.0.17 (Macintosh/20080914)
Hook up the fiemap ioctl.

This adds the fiemap inode_operation, which for us converts the 
fiemap values & flags into a getbmapx structure which can be sent
to xfs_getbmap.  The formatter then copies the bmv array back into
the user's fiemap buffer via the fiemap helpers.

If we wanted to be more clever, we could also return mapping data
for in-inode attributes, but I'm not terribly motivated to do that
just yet.

Signed-off-by: Eric Sandeen <sandeen@xxxxxxxxxxx>
---

Index: linux-2.6-xfs/fs/xfs/linux-2.6/xfs_iops.c
===================================================================
--- linux-2.6-xfs.orig/fs/xfs/linux-2.6/xfs_iops.c
+++ linux-2.6-xfs/fs/xfs/linux-2.6/xfs_iops.c
@@ -53,6 +53,7 @@
 #include <linux/namei.h>
 #include <linux/security.h>
 #include <linux/falloc.h>
+#include <linux/fiemap.h>
 
 /*
  * Bring the atime in the XFS inode uptodate.
@@ -661,6 +662,82 @@ out_error:
        return error;
 }
 
+#define XFS_FIEMAP_FLAGS       (FIEMAP_FLAG_SYNC|FIEMAP_FLAG_XATTR)
+
+STATIC int
+xfs_fiemap_format(
+       void                    **arg,
+       struct getbmapx         *bmv,
+       int                     *filled)
+{
+       int                     error = 0;
+       struct fiemap_extent_info *fieinfo = *arg;
+       u32                     fiemap_flags = 0;
+       u64                     logical, physical, length;
+
+       *filled = 0;
+       /* Do nothing for a hole */
+       if (bmv->bmv_block == -1LL)
+               return 0;
+
+       logical = BBTOB(bmv->bmv_offset);
+       physical = BBTOB(bmv->bmv_block);
+       length = BBTOB(bmv->bmv_length);
+
+       if (bmv->bmv_oflags & BMV_OF_PREALLOC)
+               fiemap_flags |= FIEMAP_EXTENT_UNWRITTEN;
+       else if (bmv->bmv_oflags & BMV_OF_DELALLOC) {
+               fiemap_flags |= FIEMAP_EXTENT_DELALLOC;
+               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)
+               return -error;
+       *filled = 1;
+       return 0;
+}
+
+STATIC int
+xfs_vn_fiemap(
+       struct inode            *inode,
+       struct fiemap_extent_info *fieinfo,
+       u64                     start,
+       u64                     length)
+{
+       xfs_inode_t             *ip = XFS_I(inode);
+       struct getbmapx         bm;
+       int                     error;
+
+       error = fiemap_check_flags(fieinfo, XFS_FIEMAP_FLAGS);
+       if (error)
+               return error;
+
+       /* Set up bmap header for xfs internal routine */
+       bm.bmv_offset = BTOBB(start);
+       /* Special case for whole file */
+       if (length == FIEMAP_MAX_OFFSET)
+               bm.bmv_length = -1LL;
+       else
+               bm.bmv_length = BTOBB(length);
+       /* xfs_getbmap takes count as header + array */
+       bm.bmv_count = fieinfo->fi_extents_max + 1;
+       bm.bmv_iflags = BMV_IF_PREALLOC;
+       if (fieinfo->fi_flags & FIEMAP_FLAG_XATTR)
+               bm.bmv_iflags |= BMV_IF_ATTRFORK;
+       if (!(fieinfo->fi_flags & FIEMAP_FLAG_SYNC))
+               bm.bmv_iflags |= BMV_IF_DELALLOC;
+
+       error = xfs_getbmap(ip, &bm, xfs_fiemap_format, fieinfo);
+       if (error)
+               return -error;
+
+       return 0;
+}
+
 static const struct inode_operations xfs_inode_operations = {
        .permission             = xfs_vn_permission,
        .truncate               = xfs_vn_truncate,
@@ -671,6 +748,7 @@ static const struct inode_operations xfs
        .removexattr            = generic_removexattr,
        .listxattr              = xfs_vn_listxattr,
        .fallocate              = xfs_vn_fallocate,
+       .fiemap                 = xfs_vn_fiemap,
 };
 
 static const struct inode_operations xfs_dir_inode_operations = {


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