[PATCH 49/51] xfs_repair: rebuild the refcount btree

Darrick J. Wong
2015-10-07T05:10:39Z

Rebuild the refcount btree with the reference count data we assembled
during phase 4.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
---
repair/phase5.c | 309 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 307 insertions(+), 2 deletions(-)

diff --git a/repair/phase5.c b/repair/phase5.c
index 734291a..8a4ec43 100644
--- a/repair/phase5.c
+++ b/repair/phase5.c
@@ -1624,6 +1624,290 @@ _("Insufficient memory to construct reverse-map cursor."));
free_slab_cursor(&rmap_cur);
}

+/* rebuild the refcount tree */
+
+#define XR_REFCOUNTBT_BLOCK_MAXRECS(mp, level) \
+ ((mp)->m_refc_mxr[(level) != 0])
+
+/*
+ * we don't have to worry here about how chewing up free extents
+ * may perturb things because reflink tree building happens before
+ * freespace tree building.
+ */
+static void
+init_refc_cursor(xfs_mount_t *mp, xfs_agnumber_t agno, bt_status_t *btree_curs)
+{
+ size_t num_recs;
+ int level;
+ bt_stat_level_t *lptr;
+ bt_stat_level_t *p_lptr;
+ xfs_extlen_t blocks_allocated;
+
+ if (!xfs_sb_version_hasreflink(&mp->m_sb)) {
+ memset(btree_curs, 0, sizeof(bt_status_t));
+ return;
+ }
+
+ lptr = &btree_curs->level[0];
+ btree_curs->init = 1;
+ btree_curs->owner = XFS_RMAP_OWN_REFC;
+
+ /*
+ * build up statistics
+ */
+ num_recs = refcount_record_count(mp, agno);
+ if (num_recs == 0) {
+ /*
+ * easy corner-case -- no refcount records
+ */
+ lptr->num_blocks = 1;
+ lptr->modulo = 0;
+ lptr->num_recs_pb = 0;
+ lptr->num_recs_tot = 0;
+
+ btree_curs->num_levels = 1;
+ btree_curs->num_tot_blocks = btree_curs->num_free_blocks = 1;
+
+ setup_cursor(mp, agno, btree_curs);
+
+ return;
+ }
+
+ blocks_allocated = lptr->num_blocks = howmany(num_recs,
+ XR_REFCOUNTBT_BLOCK_MAXRECS(mp, 0));
+
+ lptr->modulo = num_recs % lptr->num_blocks;
+ lptr->num_recs_pb = num_recs / lptr->num_blocks;
+ lptr->num_recs_tot = num_recs;
+ level = 1;
+
+ if (lptr->num_blocks > 1) {
+ for (; btree_curs->level[level-1].num_blocks > 1
+ && level < XFS_BTREE_MAXLEVELS;
+ level++) {
+ lptr = &btree_curs->level[level];
+ p_lptr = &btree_curs->level[level - 1];
+ lptr->num_blocks = howmany(p_lptr->num_blocks,
+ XR_REFCOUNTBT_BLOCK_MAXRECS(mp, level));
+ lptr->modulo = p_lptr->num_blocks % lptr->num_blocks;
+ lptr->num_recs_pb = p_lptr->num_blocks
+ / lptr->num_blocks;
+ lptr->num_recs_tot = p_lptr->num_blocks;
+
+ blocks_allocated += lptr->num_blocks;
+ }
+ }
+ ASSERT(lptr->num_blocks == 1);
+ btree_curs->num_levels = level;
+
+ btree_curs->num_tot_blocks = btree_curs->num_free_blocks
+ = blocks_allocated;
+
+ setup_cursor(mp, agno, btree_curs);
+}
+
+static void
+prop_refc_cursor(xfs_mount_t *mp, xfs_agnumber_t agno, bt_status_t *btree_curs,
+ xfs_agblock_t startbno, int level)
+{
+ struct xfs_btree_block *bt_hdr;
+ struct xfs_refcount_key *bt_key;
+ xfs_refcount_ptr_t *bt_ptr;
+ xfs_agblock_t agbno;
+ bt_stat_level_t *lptr;
+
+ level++;
+
+ if (level >= btree_curs->num_levels)
+ return;
+
+ lptr = &btree_curs->level[level];
+ bt_hdr = XFS_BUF_TO_BLOCK(lptr->buf_p);
+
+ if (be16_to_cpu(bt_hdr->bb_numrecs) == 0) {
+ /*
+ * this only happens once to initialize the
+ * first path up the left side of the tree
+ * where the agbno's are already set up
+ */
+ prop_refc_cursor(mp, agno, btree_curs, startbno, level);
+ }
+
+ if (be16_to_cpu(bt_hdr->bb_numrecs) ==
+ lptr->num_recs_pb + (lptr->modulo > 0)) {
+ /*
+ * write out current prev block, grab us a new block,
+ * and set the rightsib pointer of current block
+ */
+#ifdef XR_BLD_INO_TRACE
+ fprintf(stderr, " ino prop agbno %d ", lptr->prev_agbno);
+#endif
+ if (lptr->prev_agbno != NULLAGBLOCK) {
+ ASSERT(lptr->prev_buf_p != NULL);
+ libxfs_writebuf(lptr->prev_buf_p, 0);
+ }
+ lptr->prev_agbno = lptr->agbno;
+ lptr->prev_buf_p = lptr->buf_p;
+ agbno = get_next_blockaddr(agno, level, btree_curs);
+
+ bt_hdr->bb_u.s.bb_rightsib = cpu_to_be32(agbno);
+
+ lptr->buf_p = libxfs_getbuf(mp->m_dev,
+ XFS_AGB_TO_DADDR(mp, agno, agbno),
+ XFS_FSB_TO_BB(mp, 1));
+ lptr->agbno = agbno;
+
+ if (lptr->modulo)
+ lptr->modulo--;
+
+ /*
+ * initialize block header
+ */
+ lptr->buf_p->b_ops = &xfs_refcountbt_buf_ops;
+ bt_hdr = XFS_BUF_TO_BLOCK(lptr->buf_p);
+ memset(bt_hdr, 0, mp->m_sb.sb_blocksize);
+ xfs_btree_init_block(mp, lptr->buf_p, XFS_REFC_CRC_MAGIC,
+ level, 0, agno,
+ XFS_BTREE_CRC_BLOCKS);
+
+ bt_hdr->bb_u.s.bb_leftsib = cpu_to_be32(lptr->prev_agbno);
+
+ /*
+ * propagate extent record for first extent in new block up
+ */
+ prop_refc_cursor(mp, agno, btree_curs, startbno, level);
+ }
+ /*
+ * add inode info to current block
+ */
+ be16_add_cpu(&bt_hdr->bb_numrecs, 1);
+
+ bt_key = XFS_REFCOUNT_KEY_ADDR(bt_hdr,
+ be16_to_cpu(bt_hdr->bb_numrecs));
+ bt_ptr = XFS_REFCOUNT_PTR_ADDR(bt_hdr,
+ be16_to_cpu(bt_hdr->bb_numrecs),
+ mp->m_refc_mxr[1]);
+
+ bt_key->rc_startblock = cpu_to_be32(startbno);
+ *bt_ptr = cpu_to_be32(btree_curs->level[level-1].agbno);
+}
+
+/*
+ * rebuilds a refcount btree given a cursor.
+ */
+static void
+build_refcount_tree(xfs_mount_t *mp, xfs_agnumber_t agno, bt_status_t *btree_curs)
+{
+ xfs_agnumber_t i;
+ xfs_agblock_t j;
+ xfs_agblock_t agbno;
+ struct xfs_btree_block *bt_hdr;
+ struct xfs_refcount_irec *refc_rec;
+ struct xfs_slab_cursor *refc_cur;
+ struct xfs_refcount_rec *bt_rec;
+ struct bt_stat_level *lptr;
+ int level = btree_curs->num_levels;
+ int error;
+
+ for (i = 0; i < level; i++) {
+ lptr = &btree_curs->level[i];
+
+ agbno = get_next_blockaddr(agno, i, btree_curs);
+ lptr->buf_p = libxfs_getbuf(mp->m_dev,
+ XFS_AGB_TO_DADDR(mp, agno, agbno),
+ XFS_FSB_TO_BB(mp, 1));
+
+ if (i == btree_curs->num_levels - 1)
+ btree_curs->root = agbno;
+
+ lptr->agbno = agbno;
+ lptr->prev_agbno = NULLAGBLOCK;
+ lptr->prev_buf_p = NULL;
+ /*
+ * initialize block header
+ */
+
+ lptr->buf_p->b_ops = &xfs_refcountbt_buf_ops;
+ bt_hdr = XFS_BUF_TO_BLOCK(lptr->buf_p);
+ memset(bt_hdr, 0, mp->m_sb.sb_blocksize);
+ xfs_btree_init_block(mp, lptr->buf_p, XFS_REFC_CRC_MAGIC,
+ i, 0, agno,
+ XFS_BTREE_CRC_BLOCKS);
+ }
+
+ /*
+ * run along leaf, setting up records. as we have to switch
+ * blocks, call the prop_refc_cursor routine to set up the new
+ * pointers for the parent. that can recurse up to the root
+ * if required. set the sibling pointers for leaf level here.
+ */
+ error = init_refcount_cursor(agno, &refc_cur);
+ if (error)
+ do_error(
+_("Insufficient memory to construct refcount cursor."));
+ refc_rec = pop_slab_cursor(refc_cur);
+ lptr = &btree_curs->level[0];
+
+ for (i = 0; i < lptr->num_blocks; i++) {
+ /*
+ * block initialization, lay in block header
+ */
+ lptr->buf_p->b_ops = &xfs_refcountbt_buf_ops;
+ bt_hdr = XFS_BUF_TO_BLOCK(lptr->buf_p);
+ memset(bt_hdr, 0, mp->m_sb.sb_blocksize);
+ xfs_btree_init_block(mp, lptr->buf_p, XFS_REFC_CRC_MAGIC,
+ 0, 0, agno,
+ XFS_BTREE_CRC_BLOCKS);
+
+ bt_hdr->bb_u.s.bb_leftsib = cpu_to_be32(lptr->prev_agbno);
+ bt_hdr->bb_numrecs = cpu_to_be16(lptr->num_recs_pb +
+ (lptr->modulo > 0));
+
+ if (lptr->modulo > 0)
+ lptr->modulo--;
+
+ if (lptr->num_recs_pb > 0)
+ prop_refc_cursor(mp, agno, btree_curs,
+ refc_rec->rc_startblock, 0);
+
+ bt_rec = (struct xfs_refcount_rec *)
+ ((char *)bt_hdr + XFS_REFCOUNT_BLOCK_LEN);
+ for (j = 0; j < be16_to_cpu(bt_hdr->bb_numrecs); j++) {
+ ASSERT(refc_rec != NULL);
+ bt_rec[j].rc_startblock =
+ cpu_to_be32(refc_rec->rc_startblock);
+ bt_rec[j].rc_blockcount =
+ cpu_to_be32(refc_rec->rc_blockcount);
+ bt_rec[j].rc_refcount = cpu_to_be32(refc_rec->rc_refcount);
+
+ refc_rec = pop_slab_cursor(refc_cur);
+ }
+
+ if (refc_rec != NULL) {
+ /*
+ * get next leaf level block
+ */
+ if (lptr->prev_buf_p != NULL) {
+#ifdef XR_BLD_RL_TRACE
+ fprintf(stderr, "writing refcntbt agbno %u\n",
+ lptr->prev_agbno);
+#endif
+ ASSERT(lptr->prev_agbno != NULLAGBLOCK);
+ libxfs_writebuf(lptr->prev_buf_p, 0);
+ }
+ lptr->prev_buf_p = lptr->buf_p;
+ lptr->prev_agbno = lptr->agbno;
+ lptr->agbno = get_next_blockaddr(agno, 0, btree_curs);
+ bt_hdr->bb_u.s.bb_rightsib = cpu_to_be32(lptr->agbno);
+
+ lptr->buf_p = libxfs_getbuf(mp->m_dev,
+ XFS_AGB_TO_DADDR(mp, agno, lptr->agbno),
+ XFS_FSB_TO_BB(mp, 1));
+ }
+ }
+ free_slab_cursor(&refc_cur);
+}
+
/*
* build both the agf and the agfl for an agno given both
* btree cursors.
@@ -1637,7 +1921,8 @@ build_agf_agfl(xfs_mount_t *mp,
bt_status_t *bcnt_bt,
xfs_extlen_t freeblks, /* # free blocks in tree */
int lostblocks, /* # blocks that will be lost */
- bt_status_t *rmap_bt)
+ bt_status_t *rmap_bt,
+ bt_status_t *refcnt_bt)
{
extent_tree_node_t *ext_ptr;
xfs_buf_t *agf_buf, *agfl_buf;
@@ -1679,6 +1964,8 @@ build_agf_agfl(xfs_mount_t *mp,
agf->agf_roots[XFS_BTNUM_RMAP] = cpu_to_be32(rmap_bt->root);
agf->agf_levels[XFS_BTNUM_RMAP] = cpu_to_be32(rmap_bt->num_levels);
agf->agf_freeblks = cpu_to_be32(freeblks);
+ agf->agf_refcount_root = cpu_to_be32(refcnt_bt->root);
+ agf->agf_refcount_level = cpu_to_be32(refcnt_bt->num_levels);

/*
* Count and record the number of btree blocks consumed if required.
@@ -1796,6 +2083,10 @@ build_agf_agfl(xfs_mount_t *mp,

ASSERT(be32_to_cpu(agf->agf_roots[XFS_BTNUM_BNOi]) !=
be32_to_cpu(agf->agf_roots[XFS_BTNUM_CNTi]));
+ ASSERT(be32_to_cpu(agf->agf_refcount_root) !=
+ be32_to_cpu(agf->agf_roots[XFS_BTNUM_BNOi]));
+ ASSERT(be32_to_cpu(agf->agf_refcount_root) !=
+ be32_to_cpu(agf->agf_roots[XFS_BTNUM_CNTi]));

libxfs_writebuf(agf_buf, 0);

@@ -1865,6 +2156,7 @@ phase5_func(
bt_status_t ino_btree_curs;
bt_status_t fino_btree_curs;
bt_status_t rmap_btree_curs;
+ bt_status_t refcnt_btree_curs;
int extra_blocks = 0;
uint num_freeblocks;
xfs_extlen_t freeblks1;
@@ -1927,6 +2219,12 @@ phase5_func(
*/
init_rmapbt_cursor(mp, agno, &rmap_btree_curs);

+ /*
+ * Set up the btree cursors for the on-disk refcount btrees,
+ * which includes pre-allocating all required blocks.
+ */
+ init_refc_cursor(mp, agno, &refcnt_btree_curs);
+
num_extents = count_bno_extents_blocks(agno, &num_freeblocks);
/*
* lose two blocks per AG -- the space tree roots
@@ -2020,12 +2318,17 @@ phase5_func(
rmap_btree_curs.num_free_blocks) - 1;
}

+ if (xfs_sb_version_hasreflink(&mp->m_sb)) {
+ build_refcount_tree(mp, agno, &refcnt_btree_curs);
+ write_cursor(&refcnt_btree_curs);
+ }
+
/*
* set up agf and agfl
*/
build_agf_agfl(mp, agno, &bno_btree_curs,
&bcnt_btree_curs, freeblks1, extra_blocks,
- &rmap_btree_curs);
+ &rmap_btree_curs, &refcnt_btree_curs);
/*
* build inode allocation tree.
*/
@@ -2056,6 +2359,8 @@ phase5_func(
finish_cursor(&ino_btree_curs);
if (xfs_sb_version_hasrmapbt(&mp->m_sb))
finish_cursor(&rmap_btree_curs);
+ if (xfs_sb_version_hasreflink(&mp->m_sb))
+ finish_cursor(&refcnt_btree_curs);
if (xfs_sb_version_hasfinobt(&mp->m_sb))
finish_cursor(&fino_btree_curs);
finish_cursor(&bcnt_btree_curs);