diff options
| author | Chunwei Chen <[email protected]> | 2023-12-11 14:42:06 -0800 |
|---|---|---|
| committer | GitHub <[email protected]> | 2023-12-11 14:42:06 -0800 |
| commit | a9b937e066644c767e43aeeb46783e3139378b47 (patch) | |
| tree | 95cb398b65c5dde6b9ffd8e9cf7448fcacfa6585 | |
| parent | b1748eaee0dd9331c3ab1c7e9d548203a4d70176 (diff) | |
For db_marker inherit the db pointer for AVL comparision.
While evicting dbufs of a dnode, a marker node is added to the AVL.
The marker node should be inserted in AVL tree ahead of the dbuf its
trying to delete. The blkid and level is used to ensure this. However,
this could go wrong there's another dbufs with the same blkid and level
in DB_EVICTING state but not yet removed from AVL tree. dbuf_compare()
could fail to give the right location or could cause confusion and
trigger ASSERTs.
To ensure that the marker is inserted before the deleting dbuf, use
the pointer value of the original dbuf for comparision.
Reviewed-by: Brian Behlendorf <[email protected]>
Co-authored-by: Sanjeev Bagewadi <[email protected]>
Signed-off-by: Chunwei Chen <[email protected]>
Closes #12482
Closes #15643
| -rw-r--r-- | include/sys/dbuf.h | 1 | ||||
| -rw-r--r-- | module/zfs/dnode.c | 8 | ||||
| -rw-r--r-- | module/zfs/dnode_sync.c | 9 |
3 files changed, 17 insertions, 1 deletions
diff --git a/include/sys/dbuf.h b/include/sys/dbuf.h index 1800a7e31..2ff0bc72b 100644 --- a/include/sys/dbuf.h +++ b/include/sys/dbuf.h @@ -79,6 +79,7 @@ extern "C" { * dbuf_states_t (see comment on dn_dbufs in dnode.h). */ typedef enum dbuf_states { + DB_MARKER = -2, DB_SEARCH = -1, DB_UNCACHED, DB_FILL, diff --git a/module/zfs/dnode.c b/module/zfs/dnode.c index 7ae74ad13..ba28aa06a 100644 --- a/module/zfs/dnode.c +++ b/module/zfs/dnode.c @@ -99,6 +99,14 @@ dbuf_compare(const void *x1, const void *x2) if (likely(cmp)) return (cmp); + if (d1->db_state == DB_MARKER) { + ASSERT3S(d2->db_state, !=, DB_MARKER); + return (TREE_PCMP(d1->db_parent, d2)); + } else if (d2->db_state == DB_MARKER) { + ASSERT3S(d1->db_state, !=, DB_MARKER); + return (TREE_PCMP(d1, d2->db_parent)); + } + if (d1->db_state == DB_SEARCH) { ASSERT3S(d2->db_state, !=, DB_SEARCH); return (-1); diff --git a/module/zfs/dnode_sync.c b/module/zfs/dnode_sync.c index 8cffbdb9d..f67dad002 100644 --- a/module/zfs/dnode_sync.c +++ b/module/zfs/dnode_sync.c @@ -482,7 +482,14 @@ dnode_evict_dbufs(dnode_t *dn) zfs_refcount_is_zero(&db->db_holds)) { db_marker->db_level = db->db_level; db_marker->db_blkid = db->db_blkid; - db_marker->db_state = DB_SEARCH; + /* + * Insert a MARKER node with the same level and blkid. + * And to resolve any ties in dbuf_compare() use the + * pointer of the dbuf that we are evicting. Pass the + * address in db_parent. + */ + db_marker->db_state = DB_MARKER; + db_marker->db_parent = (void *)((uintptr_t)db - 1); avl_insert_here(&dn->dn_dbufs, db_marker, db, AVL_BEFORE); |