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authorIngo Molnar <mingo@kernel.org>2018-02-26 08:39:26 +0100
committerIngo Molnar <mingo@kernel.org>2018-02-26 08:41:15 +0100
commit3f7df3efeb415610d27aecc282ff96d4a22f0168 (patch)
tree0f66382746a1311043a25320243ff5f4b10c282e /fs/btrfs/backref.c
parentx86/mm: Optimize boot-time paging mode switching cost (diff)
parentLinux 4.16-rc3 (diff)
downloadlinux-3f7df3efeb415610d27aecc282ff96d4a22f0168.tar.gz
linux-3f7df3efeb415610d27aecc282ff96d4a22f0168.zip
Merge tag 'v4.16-rc3' into x86/mm, to pick up fixes
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'fs/btrfs/backref.c')
-rw-r--r--fs/btrfs/backref.c11
1 files changed, 10 insertions, 1 deletions
diff --git a/fs/btrfs/backref.c b/fs/btrfs/backref.c
index e4054e533f6d..f94b2d8c744a 100644
--- a/fs/btrfs/backref.c
+++ b/fs/btrfs/backref.c
@@ -1264,7 +1264,16 @@ again:
while (node) {
ref = rb_entry(node, struct prelim_ref, rbnode);
node = rb_next(&ref->rbnode);
- WARN_ON(ref->count < 0);
+ /*
+ * ref->count < 0 can happen here if there are delayed
+ * refs with a node->action of BTRFS_DROP_DELAYED_REF.
+ * prelim_ref_insert() relies on this when merging
+ * identical refs to keep the overall count correct.
+ * prelim_ref_insert() will merge only those refs
+ * which compare identically. Any refs having
+ * e.g. different offsets would not be merged,
+ * and would retain their original ref->count < 0.
+ */
if (roots && ref->count && ref->root_id && ref->parent == 0) {
if (sc && sc->root_objectid &&
ref->root_id != sc->root_objectid) {