[patch] remove xattr buffer size dependency on page size in xfsdump

[David Chinner <dgc@xxxxxxx>]

The extended attr buffer size used by xfsdump is based on page size.
The maximum buffer size the kernel will accept is 64k. On a 64k page
machine, the default buffer size will be rejected by the kernel, thereby
breaking dump and restore.

Limit the buffer size to XATTR_LIST_MAX in dump, restore and libhandle
so the kernel won't reject otherwise valid requests.

Signed-off-by: Dave Chinner <dgc@xxxxxxx>
---
 xfsdump/dump/content.c      |    2 +-
 xfsprogs/libhandle/handle.c |    5 ++++-
 xfsprogs/libhandle/jdm.c    |    4 ++++
 3 files changed, 9 insertions(+), 2 deletions(-)

Index: xfs-cmds/xfsdump/dump/content.c
===================================================================
--- xfs-cmds.orig/xfsdump/dump/content.c        2007-02-03 01:26:21.000000000 
+1100
+++ xfs-cmds/xfsdump/dump/content.c     2008-05-13 08:46:04.673298673 +1000
@@ -210,7 +210,7 @@ typedef struct extent_group_context exte
 
 /* minimum sizes for extended attributes buffers
  */
-#define EXTATTR_LISTBUF_SZ     ( 4 * pgsz )
+#define EXTATTR_LISTBUF_SZ     ( XATTR_LIST_MAX )
 #define EXTATTR_RTRVARRAY_LEN  ( 1 * pgsz )
 #define EXTATTR_DUMPBUF_SZ     ( 4 * pgsz )
 
Index: xfs-cmds/xfsprogs/libhandle/handle.c
===================================================================
--- xfs-cmds.orig/xfsprogs/libhandle/handle.c   2006-11-15 19:00:31.000000000 
+1100
+++ xfs-cmds/xfsprogs/libhandle/handle.c        2008-05-13 08:52:07.150983837 
+1000
@@ -360,8 +360,11 @@ attr_list_by_handle(
 
        memcpy(&alhreq.pos, cursor, sizeof(alhreq.pos));
        alhreq.flags = flags;
-       alhreq.buflen = bufsize;
        alhreq.buffer = buf;
+       alhreq.buflen = bufsize;
+       /* prevent needless EINVAL from the kernel */
+       if (alhreq.buflen > XATTR_LIST_MAX)
+               alhreq.buflen = XATTR_LIST_MAX;
 
        error = xfsctl(path, fd, XFS_IOC_ATTRLIST_BY_HANDLE, &alhreq);
 
Index: xfs-cmds/xfsprogs/libhandle/jdm.c
===================================================================
--- xfs-cmds.orig/xfsprogs/libhandle/jdm.c      2008-04-16 13:04:05.000000000 
+1000
+++ xfs-cmds/xfsprogs/libhandle/jdm.c   2008-05-13 08:51:23.344565394 +1000
@@ -166,6 +166,10 @@ jdm_attr_list(     jdm_fshandle_t *fshp,
        filehandle_t filehandle;
        int rval;
 
+       /* prevent needless EINVAL from the kernel */
+       if (bufsz > XATTR_LIST_MAX)
+               bufsz = XATTR_LIST_MAX;
+
        jdm_fill_filehandle( &filehandle, fshandlep, statp );
        rval = attr_list_by_handle (( void * )&filehandle,
                        sizeof( filehandle ),