xfs: add owner field to extent allocation and freeing

For the rmap btree to work, we have to feed the extent owner
information to the the allocation and freeing functions. This
information is what will end up in the rmap btree that tracks
allocated extents. While we technically don't need the owner
information when freeing extents, passing it allows us to validate
that the extent we are removing from the rmap btree actually
belonged to the owner we expected it to belong to.

We also define a special set of owner values for internal metadata
that would otherwise have no owner. This allows us to tell the
difference between metadata owned by different per-ag btrees, as
well as static fs metadata (e.g. AG headers) and internal journal
blocks.

There are also a couple of special cases we need to take care of -
during EFI recovery, we don't actually know who the original owner
was, so we need to pass a wildcard to indicate that we aren't
checking the owner for validity. We also need special handling in
growfs, as we "free" the space in the last AG when extending it, but
because it's new space it has no actual owner...

While touching the xfs_bmap_add_free() function, re-order the
parameters to put the struct xfs_mount first.

Extend the owner field to include both the owner type and some sort
of index within the owner.  The index field will be used to support
reverse mappings when reflink is enabled.

When we're freeing extents from an EFI, we don't have the owner
information available (rmap updates have their own redo items).
xfs_free_extent therefore doesn't need to do an rmap update. Make
sure that the log replay code signals this correctly.

This is based upon a patch originally from Dave Chinner. It has been
extended to add more owner information with the intent of helping
recovery operations when things go wrong (e.g. offset of user data
block in a file).

[dchinner: de-shout the xfs_rmap_*_owner helpers]
[darrick: minor style fixes suggested by Christoph Hellwig]

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

1 files changed, 16 insertions, 10 deletions

diff --git a/fs/xfs/libxfs/xfs_alloc.c b/fs/xfs/libxfs/xfs_alloc.c
index 43c7e53a6a8e..6335b8b85349 100644
--- a/fs/xfs/libxfs/xfs_alloc.c
+++ b/fs/xfs/libxfs/xfs_alloc.c
@@ -36,6 +36,7 @@
 #include "xfs_trans.h"
 #include "xfs_buf_item.h"
 #include "xfs_log.h"
+#include "xfs_rmap.h"
 
 struct workqueue_struct *xfs_alloc_wq;
 
@@ -1589,14 +1590,15 @@ error0:
 /*
  * Free the extent starting at agno/bno for length.
  */
-STATIC int			/* error */
+STATIC int
 xfs_free_ag_extent(
-	xfs_trans_t	*tp,	/* transaction pointer */
-	xfs_buf_t	*agbp,	/* buffer for a.g. freelist header */
-	xfs_agnumber_t	agno,	/* allocation group number */
-	xfs_agblock_t	bno,	/* starting block number */
-	xfs_extlen_t	len,	/* length of extent */
-	int		isfl)	/* set if is freelist blocks - no sb acctg */
+	xfs_trans_t		*tp,
+	xfs_buf_t		*agbp,
+	xfs_agnumber_t		agno,
+	xfs_agblock_t		bno,
+	xfs_extlen_t		len,
+	struct xfs_owner_info	*oinfo,
+	int			isfl)
 {
 	xfs_btree_cur_t	*bno_cur;	/* cursor for by-block btree */
 	xfs_btree_cur_t	*cnt_cur;	/* cursor for by-size btree */
@@ -2005,13 +2007,15 @@ xfs_alloc_fix_freelist(
 	 * back on the free list? Maybe we should only do this when space is
 	 * getting low or the AGFL is more than half full?
 	 */
+	xfs_rmap_ag_owner(&targs.oinfo, XFS_RMAP_OWN_AG);
 	while (pag->pagf_flcount > need) {
 		struct xfs_buf	*bp;
 
 		error = xfs_alloc_get_freelist(tp, agbp, &bno, 0);
 		if (error)
 			goto out_agbp_relse;
-		error = xfs_free_ag_extent(tp, agbp, args->agno, bno, 1, 1);
+		error = xfs_free_ag_extent(tp, agbp, args->agno, bno, 1,
+					   &targs.oinfo, 1);
 		if (error)
 			goto out_agbp_relse;
 		bp = xfs_btree_get_bufs(mp, tp, args->agno, bno, 0);
@@ -2021,6 +2025,7 @@ xfs_alloc_fix_freelist(
 	memset(&targs, 0, sizeof(targs));
 	targs.tp = tp;
 	targs.mp = mp;
+	xfs_rmap_ag_owner(&targs.oinfo, XFS_RMAP_OWN_AG);
 	targs.agbp = agbp;
 	targs.agno = args->agno;
 	targs.alignment = targs.minlen = targs.prod = targs.isfl = 1;
@@ -2709,7 +2714,8 @@ int				/* error */
 xfs_free_extent(
 	struct xfs_trans	*tp,	/* transaction pointer */
 	xfs_fsblock_t		bno,	/* starting block number of extent */
-	xfs_extlen_t		len)	/* length of extent */
+	xfs_extlen_t		len,	/* length of extent */
+	struct xfs_owner_info	*oinfo)	/* extent owner */
 {
 	struct xfs_mount	*mp = tp->t_mountp;
 	struct xfs_buf		*agbp;
@@ -2737,7 +2743,7 @@ xfs_free_extent(
 		agbno + len <= be32_to_cpu(XFS_BUF_TO_AGF(agbp)->agf_length),
 				err);
 
-	error = xfs_free_ag_extent(tp, agbp, agno, agbno, len, 0);
+	error = xfs_free_ag_extent(tp, agbp, agno, agbno, len, oinfo, 0);
 	if (error)
 		goto err;