xfs: introduce rmap btree definitions

Originally-From: Dave Chinner <dchinner@redhat.com>

Add new per-ag rmap btree definitions to the per-ag structures. The
rmap btree will sit in the empty slots on disk after the free space
btrees, and hence form a part of the array of space management
btrees. This requires the definition of the btree to be contiguous
with the free space btrees.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

5 files changed, 30 insertions, 9 deletions

diff --git a/fs/xfs/libxfs/xfs_alloc.c b/fs/xfs/libxfs/xfs_alloc.c
index 22ac3f136f21..c02d8e8419ce 100644
--- a/fs/xfs/libxfs/xfs_alloc.c
+++ b/fs/xfs/libxfs/xfs_alloc.c
@@ -2272,6 +2272,10 @@ xfs_agf_verify(
             be32_to_cpu(agf->agf_levels[XFS_BTNUM_CNT]) > XFS_BTREE_MAXLEVELS)
                 return false;
 
+        if (xfs_sb_version_hasrmapbt(&mp->m_sb) &&
+            be32_to_cpu(agf->agf_levels[XFS_BTNUM_RMAP]) > XFS_BTREE_MAXLEVELS)
+                return false;
+
         /*
          * during growfs operations, the perag is not fully initialised,
          * so we can't use it for any useful checking. growfs ensures we can't
@@ -2403,6 +2407,8 @@ xfs_alloc_read_agf(
                         be32_to_cpu(agf->agf_levels[XFS_BTNUM_BNOi]);
                 pag->pagf_levels[XFS_BTNUM_CNTi] =
                         be32_to_cpu(agf->agf_levels[XFS_BTNUM_CNTi]);
+                pag->pagf_levels[XFS_BTNUM_RMAPi] =
+                        be32_to_cpu(agf->agf_levels[XFS_BTNUM_RMAPi]);
                 spin_lock_init(&pag->pagb_lock);
                 pag->pagb_count = 0;
                 pag->pagb_tree = RB_ROOT;
diff --git a/fs/xfs/libxfs/xfs_btree.c b/fs/xfs/libxfs/xfs_btree.c
index 4fc46529753d..4066b01a1807 100644
--- a/fs/xfs/libxfs/xfs_btree.c
+++ b/fs/xfs/libxfs/xfs_btree.c
@@ -44,9 +44,9 @@ kmem_zone_t	*xfs_btree_cur_zone;
  * Btree magic numbers.
  */
 static const __uint32_t xfs_magics[2][XFS_BTNUM_MAX] = {
-        { XFS_ABTB_MAGIC, XFS_ABTC_MAGIC, XFS_BMAP_MAGIC, XFS_IBT_MAGIC,
+        { XFS_ABTB_MAGIC, XFS_ABTC_MAGIC, 0, XFS_BMAP_MAGIC, XFS_IBT_MAGIC,
           XFS_FIBT_MAGIC },
-        { XFS_ABTB_CRC_MAGIC, XFS_ABTC_CRC_MAGIC,
+        { XFS_ABTB_CRC_MAGIC, XFS_ABTC_CRC_MAGIC, XFS_RMAP_CRC_MAGIC,
           XFS_BMAP_CRC_MAGIC, XFS_IBT_CRC_MAGIC, XFS_FIBT_CRC_MAGIC }
 };
 #define xfs_btree_magic(cur) \
diff --git a/fs/xfs/libxfs/xfs_btree.h b/fs/xfs/libxfs/xfs_btree.h
index ac5cd6ef6859..25f1b69e7515 100644
--- a/fs/xfs/libxfs/xfs_btree.h
+++ b/fs/xfs/libxfs/xfs_btree.h
@@ -77,6 +77,7 @@ union xfs_btree_rec {
 #define XFS_BTNUM_BMAP  ((xfs_btnum_t)XFS_BTNUM_BMAPi)
 #define XFS_BTNUM_INO   ((xfs_btnum_t)XFS_BTNUM_INOi)
 #define XFS_BTNUM_FINO  ((xfs_btnum_t)XFS_BTNUM_FINOi)
+#define XFS_BTNUM_RMAP  ((xfs_btnum_t)XFS_BTNUM_RMAPi)
 
 /*
  * For logging record fields.
@@ -109,6 +110,7 @@ do {    \
         case XFS_BTNUM_BMAP: __XFS_BTREE_STATS_INC(__mp, bmbt, stat); break; \
         case XFS_BTNUM_INO: __XFS_BTREE_STATS_INC(__mp, ibt, stat); break; \
         case XFS_BTNUM_FINO: __XFS_BTREE_STATS_INC(__mp, fibt, stat); break; \
+        case XFS_BTNUM_RMAP: break;     \
         case XFS_BTNUM_MAX: ASSERT(0); /* fucking gcc */ ; break;       \
         }       \
 } while (0)
@@ -129,6 +131,7 @@ do {    \
                 __XFS_BTREE_STATS_ADD(__mp, ibt, stat, val); break; \
         case XFS_BTNUM_FINO:    \
                 __XFS_BTREE_STATS_ADD(__mp, fibt, stat, val); break; \
+        case XFS_BTNUM_RMAP: break; \
         case XFS_BTNUM_MAX: ASSERT(0); /* fucking gcc */ ; break; \
         }       \
 } while (0)
diff --git a/fs/xfs/libxfs/xfs_format.h b/fs/xfs/libxfs/xfs_format.h
index adb204d40f22..74f4d3da598c 100644
--- a/fs/xfs/libxfs/xfs_format.h
+++ b/fs/xfs/libxfs/xfs_format.h
@@ -455,6 +455,7 @@ xfs_sb_has_compat_feature(
 }
 
 #define XFS_SB_FEAT_RO_COMPAT_FINOBT   (1 << 0)         /* free inode btree */
+#define XFS_SB_FEAT_RO_COMPAT_RMAPBT   (1 << 1)         /* reverse map btree */
 #define XFS_SB_FEAT_RO_COMPAT_ALL \
                 (XFS_SB_FEAT_RO_COMPAT_FINOBT)
 #define XFS_SB_FEAT_RO_COMPAT_UNKNOWN   ~XFS_SB_FEAT_RO_COMPAT_ALL
@@ -538,6 +539,12 @@ static inline bool xfs_sb_version_hasmetauuid(struct xfs_sb *sbp)
                 (sbp->sb_features_incompat & XFS_SB_FEAT_INCOMPAT_META_UUID);
 }
 
+static inline bool xfs_sb_version_hasrmapbt(struct xfs_sb *sbp)
+{
+        return (XFS_SB_VERSION_NUM(sbp) == XFS_SB_VERSION_5) &&
+                (sbp->sb_features_ro_compat & XFS_SB_FEAT_RO_COMPAT_RMAPBT);
+}
+
 /*
  * end of superblock version macros
  */
@@ -598,10 +605,10 @@ xfs_is_quota_inode(struct xfs_sb *sbp, xfs_ino_t ino)
 #define XFS_AGI_GOOD_VERSION(v) ((v) == XFS_AGI_VERSION)
 
 /*
- * Btree number 0 is bno, 1 is cnt.  This value gives the size of the
+ * Btree number 0 is bno, 1 is cnt, 2 is rmap. This value gives the size of the
  * arrays below.
  */
-#define XFS_BTNUM_AGF   ((int)XFS_BTNUM_CNTi + 1)
+#define XFS_BTNUM_AGF   ((int)XFS_BTNUM_RMAPi + 1)
 
 /*
  * The second word of agf_levels in the first a.g. overlaps the EFS
@@ -618,12 +625,10 @@ typedef struct xfs_agf {
         __be32          agf_seqno;      /* sequence # starting from 0 */
         __be32          agf_length;     /* size in blocks of a.g. */
         /*
-         * Freespace information
+         * Freespace and rmap information
          */
         __be32          agf_roots[XFS_BTNUM_AGF];       /* root blocks */
-        __be32          agf_spare0;     /* spare field */
         __be32          agf_levels[XFS_BTNUM_AGF];      /* btree levels */
-        __be32          agf_spare1;     /* spare field */
 
         __be32          agf_flfirst;    /* first freelist block's index */
         __be32          agf_fllast;     /* last freelist block's index */
@@ -1308,6 +1313,13 @@ typedef __be32 xfs_inobt_ptr_t;
 #define XFS_FIBT_BLOCK(mp)              ((xfs_agblock_t)(XFS_IBT_BLOCK(mp) + 1))
 
 /*
+ * Reverse mapping btree format definitions
+ *
+ * There is a btree for the reverse map per allocation group
+ */
+#define XFS_RMAP_CRC_MAGIC      0x524d4233      /* 'RMB3' */
+
+/*
  * The first data block of an AG depends on whether the filesystem was formatted
  * with the finobt feature. If so, account for the finobt reserved root btree
  * block.
diff --git a/fs/xfs/libxfs/xfs_types.h b/fs/xfs/libxfs/xfs_types.h
index b79dc66b2ecd..3d503647f26b 100644
--- a/fs/xfs/libxfs/xfs_types.h
+++ b/fs/xfs/libxfs/xfs_types.h
@@ -108,8 +108,8 @@ typedef enum {
 } xfs_lookup_t;
 
 typedef enum {
-        XFS_BTNUM_BNOi, XFS_BTNUM_CNTi, XFS_BTNUM_BMAPi, XFS_BTNUM_INOi,
-        XFS_BTNUM_FINOi, XFS_BTNUM_MAX
+        XFS_BTNUM_BNOi, XFS_BTNUM_CNTi, XFS_BTNUM_RMAPi, XFS_BTNUM_BMAPi,
+        XFS_BTNUM_INOi, XFS_BTNUM_FINOi, XFS_BTNUM_MAX
 } xfs_btnum_t;
 
 struct xfs_name {