[PATCH 2/6] xfs: shadow agfl indexes in the per-ag structures

[Dave Chinner <david@xxxxxxxxxxxxx>]

From: Dave Chinner <dchinner@xxxxxxxxxx>

To verify that the AGFL contents is sane, we need to have access to
the indexes that tell us what part of the AGFL is active. We cannot
access the AGF buffer from the AGFL verifier, so we need to shadow
these values in the struct xfs_perag so we check them when required.

Signed-off-by: Dave Chinner <dchinner@xxxxxxxxxx>
---
 fs/xfs/libxfs/xfs_alloc.c | 4 ++++
 fs/xfs/xfs_mount.h        | 2 ++
 2 files changed, 6 insertions(+)

diff --git a/fs/xfs/libxfs/xfs_alloc.c b/fs/xfs/libxfs/xfs_alloc.c
index 23559b9..1aef556 100644
--- a/fs/xfs/libxfs/xfs_alloc.c
+++ b/fs/xfs/libxfs/xfs_alloc.c
@@ -2255,6 +2255,7 @@ xfs_alloc_get_freelist(
        be32_add_cpu(&agf->agf_flcount, -1);
        xfs_trans_agflist_delta(tp, -1);
        pag->pagf_flcount--;
+       pag->pagf_flfirst = be32_to_cpu(agf->agf_flfirst);
        xfs_perag_put(pag);
 
        logflags = XFS_AGF_FLFIRST | XFS_AGF_FLCOUNT;
@@ -2363,6 +2364,7 @@ xfs_alloc_put_freelist(
        be32_add_cpu(&agf->agf_flcount, 1);
        xfs_trans_agflist_delta(tp, 1);
        pag->pagf_flcount++;
+       pag->pagf_fllast = be32_to_cpu(agf->agf_fllast);
 
        logflags = XFS_AGF_FLLAST | XFS_AGF_FLCOUNT;
        if (btreeblk) {
@@ -2547,6 +2549,8 @@ xfs_alloc_read_agf(
                pag->pagf_freeblks = be32_to_cpu(agf->agf_freeblks);
                pag->pagf_btreeblks = be32_to_cpu(agf->agf_btreeblks);
                pag->pagf_flcount = be32_to_cpu(agf->agf_flcount);
+               pag->pagf_flfirst = be32_to_cpu(agf->agf_flfirst);
+               pag->pagf_fllast = be32_to_cpu(agf->agf_fllast);
                pag->pagf_longest = be32_to_cpu(agf->agf_longest);
                pag->pagf_levels[XFS_BTNUM_BNOi] =
                        be32_to_cpu(agf->agf_levels[XFS_BTNUM_BNOi]);
diff --git a/fs/xfs/xfs_mount.h b/fs/xfs/xfs_mount.h
index b36676c..3eb1b20 100644
--- a/fs/xfs/xfs_mount.h
+++ b/fs/xfs/xfs_mount.h
@@ -340,6 +340,8 @@ typedef struct xfs_perag {
        __uint8_t       pagf_levels[XFS_BTNUM_AGF];
                                        /* # of levels in bno & cnt btree */
        __uint32_t      pagf_flcount;   /* count of blocks in freelist */
+       __uint32_t      pagf_flfirst;   /* first freelist block's index */
+       __uint32_t      pagf_fllast;    /* last freelist block's index */
        xfs_extlen_t    pagf_freeblks;  /* total free blocks */
        xfs_extlen_t    pagf_longest;   /* longest free space */
        __uint32_t      pagf_btreeblks; /* # of blocks held in AGF btrees */
-- 
2.8.0.rc3