[RFC PATCH 09/11] xfs: use and update the finobt on inode allocation

Brian Foster
2013-09-03T18:25:48Z

Replace xfs_dialloc_ag() with an implementation that looks for a
record in the finobt. The finobt only tracks records with at least
one free inode. This eliminates the need for the intra-ag scan in
the original algorithm. Once the inode is allocated, update the
finobt appropriately (possibly removing the record) as well as the
inobt.

Move the original xfs_dialloc_ag() algorithm to
xfs_dialloc_ag_slow() and fall back as such if finobt support is
not enabled.

Signed-off-by: Brian Foster <bfoster@redhat.com>
---
fs/xfs/xfs_ialloc.c | 136 +++++++++++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 135 insertions(+), 1 deletion(-)

diff --git a/fs/xfs/xfs_ialloc.c b/fs/xfs/xfs_ialloc.c
index e64a728..516f4af 100644
--- a/fs/xfs/xfs_ialloc.c
+++ b/fs/xfs/xfs_ialloc.c
@@ -708,7 +708,7 @@ xfs_ialloc_get_rec(
* available.
*/
STATIC int
-xfs_dialloc_ag(
+xfs_dialloc_ag_slow(
struct xfs_trans *tp,
struct xfs_buf *agbp,
xfs_ino_t parent,
@@ -966,6 +966,140 @@ error0:
return error;
}

+STATIC int
+xfs_dialloc_ag(
+ struct xfs_trans *tp,
+ struct xfs_buf *agbp,
+ xfs_ino_t parent,
+ xfs_ino_t *inop)
+{
+ struct xfs_mount *mp = tp->t_mountp;
+ struct xfs_agi *agi = XFS_BUF_TO_AGI(agbp);
+ xfs_agnumber_t agno = be32_to_cpu(agi->agi_seqno);
+ xfs_agino_t pagino = XFS_INO_TO_AGINO(mp, parent);
+ struct xfs_perag *pag;
+ struct xfs_btree_cur *fcur;
+ struct xfs_btree_cur *icur;
+ struct xfs_inobt_rec_incore frec;
+ struct xfs_inobt_rec_incore irec;
+ xfs_ino_t ino;
+ int error;
+ int offset;
+ int i;
+
+ if (!xfs_sb_version_hasfinobt(&mp->m_sb))
+ return xfs_dialloc_ag_slow(tp, agbp, parent, inop);
+
+ pag = xfs_perag_get(mp, agno);
+
+ /*
+ * If pagino is 0 (this is the root inode allocation) use newino.
+ * This must work because we've just allocated some.
+ */
+ if (!pagino)
+ pagino = be32_to_cpu(agi->agi_newino);
+
+ fcur = xfs_inobt_init_cursor(mp, tp, agbp, agno, XFS_BTNUM_FINO);
+ icur = xfs_inobt_init_cursor(mp, tp, agbp, agno, XFS_BTNUM_INO);
+
+ error = xfs_check_agi_freecount(fcur, agi);
+ if (error)
+ goto error;
+ error = xfs_check_agi_freecount(icur, agi);
+ if (error)
+ goto error;
+
+ /*
+ * Search the finobt.
+ */
+ error = xfs_inobt_lookup(fcur, pagino, XFS_LOOKUP_LE, &i);
+ if (error)
+ goto error;
+ if (i == 0) {
+ error = xfs_inobt_lookup(fcur, pagino, XFS_LOOKUP_GE, &i);
+ if (error)
+ goto error;
+ XFS_WANT_CORRUPTED_GOTO(i == 1, error);
+ }
+
+ error = xfs_inobt_get_rec(fcur, &frec, &i);
+ if (error)
+ goto error;
+ XFS_WANT_CORRUPTED_GOTO(i == 1, error);
+
+ offset = xfs_lowbit64(frec.ir_free);
+ ASSERT(offset >= 0);
+ ASSERT(offset < XFS_INODES_PER_CHUNK);
+ ASSERT((XFS_AGINO_TO_OFFSET(mp, frec.ir_startino) %
+ XFS_INODES_PER_CHUNK) == 0);
+ ino = XFS_AGINO_TO_INO(mp, agno, frec.ir_startino + offset);
+
+ /*
+ * Modify or remove the finobt record.
+ */
+ frec.ir_free &= ~XFS_INOBT_MASK(offset);
+ frec.ir_freecount--;
+ if (frec.ir_freecount)
+ error = xfs_inobt_update(fcur, &frec);
+ else
+ error = xfs_btree_delete(fcur, &i);
+ if (error)
+ goto error;
+
+ /*
+ * Lookup and modify the equivalent record in the inobt.
+ */
+ error = xfs_inobt_lookup(icur, frec.ir_startino, XFS_LOOKUP_EQ, &i);
+ if (error)
+ goto error;
+ XFS_WANT_CORRUPTED_GOTO(i == 1, error);
+
+ error = xfs_inobt_get_rec(icur, &irec, &i);
+ if (error)
+ goto error;
+ XFS_WANT_CORRUPTED_GOTO(i == 1, error);
+ ASSERT((XFS_AGINO_TO_OFFSET(mp, irec.ir_startino) %
+ XFS_INODES_PER_CHUNK) == 0);
+
+ irec.ir_free &= ~XFS_INOBT_MASK(offset);
+ irec.ir_freecount--;
+
+ XFS_WANT_CORRUPTED_GOTO((frec.ir_free == irec.ir_free) &&
+ (frec.ir_freecount == irec.ir_freecount),
+ error);
+
+ error = xfs_inobt_update(icur, &irec);
+ if (error)
+ goto error;
+
+ /*
+ * Update the perag and superblock.
+ */
+ be32_add_cpu(&agi->agi_freecount, -1);
+ xfs_ialloc_log_agi(tp, agbp, XFS_AGI_FREECOUNT);
+ pag->pagi_freecount--;
+
+ xfs_trans_mod_sb(tp, XFS_TRANS_SB_IFREE, -1);
+ xfs_perag_put(pag);
+
+ error = xfs_check_agi_freecount(fcur, agi);
+ if (error)
+ goto error;
+ error = xfs_check_agi_freecount(icur, agi);
+ if (error)
+ goto error;
+
+ xfs_btree_del_cursor(icur, XFS_BTREE_NOERROR);
+ xfs_btree_del_cursor(fcur, XFS_BTREE_ERROR);
+ *inop = ino;
+ return 0;
+error:
+ xfs_perag_put(pag);
+ xfs_btree_del_cursor(icur, XFS_BTREE_ERROR);
+ xfs_btree_del_cursor(fcur, XFS_BTREE_ERROR);
+ return error;
+}
+
/*
* Allocate an inode on disk.
*
--
1.8.1.4