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_inobt() and fall back as such if finobt support is
not enabled.
Signed-off-by: Brian Foster <bfoster@xxxxxxxxxx>
---
fs/xfs/xfs_ialloc.c | 295 +++++++++++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 290 insertions(+), 5 deletions(-)
diff --git a/fs/xfs/xfs_ialloc.c b/fs/xfs/xfs_ialloc.c
index 3fdb9fb..74131ab 100644
--- a/fs/xfs/xfs_ialloc.c
+++ b/fs/xfs/xfs_ialloc.c
@@ -710,13 +710,10 @@ xfs_ialloc_get_rec(
}
/*
- * Allocate an inode.
- *
- * The caller selected an AG for us, and made sure that free inodes are
- * available.
+ * Allocate an inode using the inobt-only algorithm.
*/
STATIC int
-xfs_dialloc_ag(
+xfs_dialloc_ag_inobt(
struct xfs_trans *tp,
struct xfs_buf *agbp,
xfs_ino_t parent,
@@ -975,6 +972,294 @@ error0:
}
/*
+ * Use the free inode btree to allocate an inode based on distance from the
+ * parent. Note that the provided cursor may be deleted and replaced.
+ */
+STATIC int
+xfs_dialloc_ag_finobt_near(
+ xfs_agino_t pagino,
+ struct xfs_btree_cur **ocur,
+ struct xfs_inobt_rec_incore *rec)
+{
+ struct xfs_btree_cur *lcur = *ocur; /* left search cursor */
+ struct xfs_btree_cur *rcur; /* right search cursor */
+ struct xfs_inobt_rec_incore rrec;
+ int error;
+ int i, j;
+
+ error = xfs_inobt_lookup(lcur, pagino, XFS_LOOKUP_LE, &i);
+ if (error)
+ return error;
+
+ if (i == 1) {
+ error = xfs_inobt_get_rec(lcur, rec, &i);
+ if (error)
+ return error;
+ XFS_WANT_CORRUPTED_RETURN(i == 1);
+
+ /*
+ * See if we've landed in the parent inode record. The finobt
+ * only tracks chunks with at least one free inode, so record
+ * existence is enough.
+ */
+ if (pagino >= rec->ir_startino &&
+ pagino < (rec->ir_startino + XFS_INODES_PER_CHUNK))
+ return 0;
+ }
+
+ error = xfs_btree_dup_cursor(lcur, &rcur);
+ if (error)
+ return error;
+
+ error = xfs_inobt_lookup(rcur, pagino, XFS_LOOKUP_GE, &j);
+ if (error)
+ goto error_rcur;
+ if (j == 1) {
+ error = xfs_inobt_get_rec(rcur, &rrec, &j);
+ if (error)
+ goto error_rcur;
+ XFS_WANT_CORRUPTED_GOTO(j == 1, error_rcur);
+ }
+
+ XFS_WANT_CORRUPTED_GOTO(i == 1 || j == 1, error_rcur);
+ if (i == 1 && j == 1) {
+ /*
+ * Both the left and right records are valid. Choose the closer
+ * inode chunk to the target.
+ */
+ if ((pagino - rec->ir_startino + XFS_INODES_PER_CHUNK - 1) >
+ (rrec.ir_startino - pagino)) {
+ *rec = rrec;
+ xfs_btree_del_cursor(lcur, XFS_BTREE_NOERROR);
+ *ocur = rcur;
+ } else {
+ xfs_btree_del_cursor(rcur, XFS_BTREE_NOERROR);
+ }
+ } else if (j == 1) {
+ /* only the right record is valid */
+ *rec = rrec;
+ xfs_btree_del_cursor(lcur, XFS_BTREE_NOERROR);
+ *ocur = rcur;
+ } else if (i == 1) {
+ /* only the left record is valid */
+ xfs_btree_del_cursor(rcur, XFS_BTREE_NOERROR);
+ }
+
+ return 0;
+
+error_rcur:
+ xfs_btree_del_cursor(rcur, XFS_BTREE_ERROR);
+ return error;
+}
+
+/*
+ * Use the free inode btree to find a free inode based on a newino hint. If
+ * the hint is NULL, find the first free inode in the AG.
+ */
+STATIC int
+xfs_dialloc_ag_finobt_newino(
+ struct xfs_agi *agi,
+ struct xfs_btree_cur *cur,
+ struct xfs_inobt_rec_incore *rec)
+{
+ int error;
+ int i;
+
+ if (agi->agi_newino != cpu_to_be32(NULLAGINO)) {
+ error = xfs_inobt_lookup(cur, agi->agi_newino, XFS_LOOKUP_EQ,
+ &i);
+ if (error)
+ return error;
+ if (i == 1) {
+ error = xfs_inobt_get_rec(cur, rec, &i);
+ if (error)
+ return error;
+ XFS_WANT_CORRUPTED_RETURN(i == 1);
+
+ return 0;
+ }
+ }
+
+ /*
+ * Find the first inode available in the AG.
+ */
+ error = xfs_inobt_lookup(cur, 0, XFS_LOOKUP_GE, &i);
+ if (error)
+ return error;
+ XFS_WANT_CORRUPTED_RETURN(i == 1);
+
+ error = xfs_inobt_get_rec(cur, rec, &i);
+ if (error)
+ return error;
+ XFS_WANT_CORRUPTED_RETURN(i == 1);
+
+ return 0;
+}
+
+/*
+ * Update the inobt based on a modification made to the finobt. Also ensure that
+ * the records from both trees are equivalent post-modification.
+ */
+STATIC int
+xfs_dialloc_ag_update_inobt(
+ struct xfs_btree_cur *cur, /* inobt cursor */
+ struct xfs_inobt_rec_incore *frec, /* finobt record */
+ int offset) /* inode offset */
+{
+ struct xfs_inobt_rec_incore rec;
+ int error;
+ int i;
+
+ error = xfs_inobt_lookup(cur, frec->ir_startino, XFS_LOOKUP_EQ, &i);
+ if (error)
+ return error;
+ XFS_WANT_CORRUPTED_RETURN(i == 1);
+
+ error = xfs_inobt_get_rec(cur, &rec, &i);
+ if (error)
+ return error;
+ XFS_WANT_CORRUPTED_RETURN(i == 1);
+ ASSERT((XFS_AGINO_TO_OFFSET(cur->bc_mp, rec.ir_startino) %
+ XFS_INODES_PER_CHUNK) == 0);
+
+ rec.ir_free &= ~XFS_INOBT_MASK(offset);
+ rec.ir_freecount--;
+
+ XFS_WANT_CORRUPTED_RETURN((rec.ir_free == frec->ir_free) &&
+ (rec.ir_freecount == frec->ir_freecount));
+
+ error = xfs_inobt_update(cur, &rec);
+ if (error)
+ return error;
+
+ return 0;
+}
+
+/*
+ * Allocate an inode using the free inode btree, if available. Otherwise, fall
+ * back to the inobt search algorithm.
+ *
+ * The caller selected an AG for us, and made sure that free inodes are
+ * available.
+ */
+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_agnumber_t pagno = XFS_INO_TO_AGNO(mp, parent);
+ xfs_agino_t pagino = XFS_INO_TO_AGINO(mp, parent);
+ struct xfs_perag *pag;
+ struct xfs_btree_cur *cur; /* finobt cursor */
+ struct xfs_btree_cur *icur; /* inobt cursor */
+ struct xfs_inobt_rec_incore rec;
+ xfs_ino_t ino;
+ int error;
+ int offset;
+ int i;
+
+ if (!xfs_sb_version_hasfinobt(&mp->m_sb))
+ return xfs_dialloc_ag_inobt(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);
+
+ cur = xfs_inobt_init_cursor(mp, tp, agbp, agno, XFS_BTNUM_FINO);
+
+ error = xfs_check_agi_freecount(cur, agi);
+ if (error)
+ goto error_cur;
+
+ /*
+ * The search algorithm depends on whether we're in the same AG as the
+ * parent. If so, find the closest available inode to the parent. If
+ * not, consider the agi hint or find the first free inode in the AG.
+ */
+ if (agno == pagno)
+ error = xfs_dialloc_ag_finobt_near(pagino, &cur, &rec);
+ else
+ error = xfs_dialloc_ag_finobt_newino(agi, cur, &rec);
+ if (error)
+ goto error_cur;
+
+ offset = xfs_lowbit64(rec.ir_free);
+ ASSERT(offset >= 0);
+ ASSERT(offset < XFS_INODES_PER_CHUNK);
+ ASSERT((XFS_AGINO_TO_OFFSET(mp, rec.ir_startino) %
+ XFS_INODES_PER_CHUNK) == 0);
+ ino = XFS_AGINO_TO_INO(mp, agno, rec.ir_startino + offset);
+
+ /*
+ * Modify or remove the finobt record.
+ */
+ rec.ir_free &= ~XFS_INOBT_MASK(offset);
+ rec.ir_freecount--;
+ if (rec.ir_freecount)
+ error = xfs_inobt_update(cur, &rec);
+ else
+ error = xfs_btree_delete(cur, &i);
+ if (error)
+ goto error_cur;
+
+ /*
+ * The finobt has now been updated appropriately. We haven't updated the
+ * agi and superblock yet, so we can create an inobt cursor and validate
+ * the original freecount. If all is well, make the equivalent update to
+ * the inobt using the finobt record and offset information.
+ */
+ icur = xfs_inobt_init_cursor(mp, tp, agbp, agno, XFS_BTNUM_INO);
+
+ error = xfs_check_agi_freecount(icur, agi);
+ if (error)
+ goto error_icur;
+
+ error = xfs_dialloc_ag_update_inobt(icur, &rec, offset);
+ if (error)
+ goto error_icur;
+
+ /*
+ * Both trees have now been updated. We must update the perag and
+ * superblock before we can check the freecount for each btree.
+ */
+ 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);
+
+ error = xfs_check_agi_freecount(icur, agi);
+ if (error)
+ goto error_icur;
+ error = xfs_check_agi_freecount(cur, agi);
+ if (error)
+ goto error_icur;
+
+ xfs_btree_del_cursor(icur, XFS_BTREE_NOERROR);
+ xfs_btree_del_cursor(cur, XFS_BTREE_NOERROR);
+ xfs_perag_put(pag);
+ *inop = ino;
+ return 0;
+
+error_icur:
+ xfs_btree_del_cursor(icur, XFS_BTREE_ERROR);
+error_cur:
+ xfs_btree_del_cursor(cur, XFS_BTREE_ERROR);
+ xfs_perag_put(pag);
+ return error;
+}
+
+/*
* Allocate an inode on disk.
*
* Mode is used to tell whether the new inode will need space, and whether it
--
1.8.3.1
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